Note: Descriptions are shown in the official language in which they were submitted.
DELAMINATION RESISTANT, WELDABLE AND
FORMABLE LIGHT WEIGHT COMPOSITES
FIELD OF THE INVENTION
[001] The present invention relates generally to fiber-filled polymeric
materials, and
to composite materials that Include a layer of the fiber-filled polymeric
material, and
more particularly to sandwich composites that include a layer of the fiber-
filled
polymeric material and a metallic layer.
BACKGROUND
= [002] Light weight composites which have a good balance of high
stiffness, high
toughness, and low weight are used in many .applications which require low
flexibility
and can benefit by reduced part weight.
[003] Transportation is one industry which has a need for such materials, for
example, as a
component of a vehicle or for an object (such as a container) which is being
transported.
[004] The ever present need to lighten the weight of transportation vehicles,
as well
as objects that are being transported, as well as the need for other lighter
weight
materials, and substitutes for conventional steel materials, has caused
industry to
investigate new composite materials, and particularly sandwich composite
materials.
Earlier applications filed by the present inventors have described such
efforts In
detail.
[005] Unfortunately, the performance requirements imposed for many commercial
applications generally create competing design tensions. A material meeting
one
need (e.g., stampability) may not necessarily meet another need, such as
weldability.
As such, until the work of the present inventors, materials able to meet the
various
needs in a commercially viable, manner have yet to be employed. Efforts- to
employ
sandwich composites similarly have been unsuccessful, with complications often
arising from the inability to realize high integrity bonding among layers, as
well as
long term corrosion resistance. Of course, when adding in the need for
stampability
and weldability, many such materials have been ruled out as viable candidates.
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Accordingly, notwithstanding the many efforts in the art to date, until the
work of
present inventors, there has remained a need for an improved composite
material,
such as a sandwich composite material, which can be substituted for
conventional
steel materials without the need for significant investment in capital for
those
incorporating the materials into their finished products. There also has
remained a
need for a material that can be stamped. There also has remained a need for a
material that can be welded, and especially welded using conventional welding
techniques and/or equipment.. There also has remained a need for a material
that
exhibits long term durability characteristics such as one of both of
resistance to
corrosion or resistance to delamination (e.g., resistance to delamination in
ordinary
service conditions, such as ordinary service conditions of automotive vehicle
and can
endure such conditions without delamination for extended period of time (e.g.,
3, 5.
10, years or longer) of the layers of the composite. Further there remains a
need for
a polymeric-based composite mass that can be used alone or in combination with
other materials, such as layered materials, which exhibits good
processability,
durability, electrical characteristics (e.g., charge dissipation
characterisitics), or any
combination thereof.
[006] Also, there continues to exist a need for a weldable light weight
composite
having a polymeric layer having improved weldability (i.e., having a larger
processing
window for obtaining acceptable welds). We!debility may be measured by the
weld
current range (i.e., the difference between the maximum current that produces
an
acceptable weld and the minimum current that produces an acceptable weld, with
other conditions such as weld pressure and weld time being kept constant,
preferably
at values that produce. the best welds). We[debility may be measured by the
weld
time range (i.e., the difference between the maximum weld time that produces
an
acceptable weld and the minimum current that produces an acceptable weld, with
the
other conditions such as weld pressure and weld current kept constant,
preferably at
Values that results in the best welds).
SUMMARY OF THE INVENTION
[007) The present invention in various aspects meets some or all of the above
needs and is predicated upon the unexpected and surprising recognition that
certain
unique materials combinations actually are capable of providing a composite
material, such as a sandwich composite material, that has excellent drawing
capabilities, is weldable (and may even be welded using conventional
techniques
and/or equipment), and resists delamination in the face of conditions
ordinarily
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conducive to delamination. So effective are the materials and other teachings
herein
at realizing a substitute for steel in numerous conventional steel
applications that it
effectively can be used as a drop-in material in place of steel. Thus, it is
expected
that manufacturers can employ the present materials in their manufacturing
operations without the need for acquiring new equipment or other capital
investments. Substantial weight savings are possible as well for resulting
articles.
[008) A variety of aspects are disclosed herein and the teachings for one
aspect
may be employed in combination with the teachings of other aspects as will be
appreciated upon review of the following description.
[009] In a general sense, the present teachings contemplates a composite
material,
comprising: a polymeric-based matrix that includes a mixture of: at least one
first
thermoplastic polymer; and at least one second thermoplastic polymer that is
different from the first thermoplastic polymer; and a mass of metallic fibers
distributed
throughout the matrix to form a composite mass with the polymeric-based
matrix, the
mass of metallic fibers: including a plurality of metallic fibers optionally
having at least
one generally flat surface, and being present in concentration greater than
about 3%
by volume, based on the total volume of the composite mass.
100101 The teachings also contemplate one or any combination of the following
features in this summary of the invention, as well as those features -
described
throughout the following detailed description. By way of illustration, at
least one first
thermoplastic polymer may include at least one polyolefinic polymer (e.g., a
linear
low density polyethylene); the at least one second polymer includes an
elastomer,
such as an ethylene-octene copolymer. The polymeric-based matrix may include a
polymer that is capable of cross-linking. For example, the polymeric-based
matrix
include a polymer that is capable of cross-linking by application of an
external
stimulus selected from radiation (e.g., Ultraviolet radiation and/or, infrared
radiation),
moisture, heat, or any combination thereof. The relative weight and/or
proportions of
the first thermoplastic polymer to the second thermoplastic polymer may range
from
about 1:1 to about 10:1. More preferably about 2:1 to about 5:1.
[0011] The composite mass may be attached to a substrate, such as a metal
sheet
(e.g., it is sandwiched between opposing metal sheets); the substrate or metal
sheet
prior to or after being attached to the composite mass may be coated on
opposing
major surfaces of the sheet with a coating one or more coatings (e.g., one
that
include zinc, phosphate, or both) for resisting corrosion; the metal of the
substrate or
any sheet may be aluminum, a steel (which may be a high strength steel (e.g.,
a
steel having mechanical strength characteristics consistent with a grade such
as
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having a yield strength of about 240 MPa or greater, about 300 MPa or greater,
about 400 MPa or greater, about 450 MPa or greater, about 500 MPa or greater,
or
about 550 or greater; an ultimate tensile strength of about 340 MPa or
greater, about
450 MPa or greater, about 500 MPa or greater, about 500 MPa or greater, about
600
MPa greater, or about 650 or greater; or both) or a steel that otherwise
includes an
alloying ingredient selected from nickel, manganese, copper, niobium,
vanadium,
chromium, molybdenum, titanium, calcium, one or more rare earth elements,
zirconium, nitrogen or any combination).
[0012] The mass of metallic fibers may include a plurality of fibers that are
coated
with a composition for resisting corrosion: for instance a plurality of fibers
may be
coated with a composition for defining a sacrificial anode so that resistance
to
corrosion is provided for a metal to which the composite mass is attached due
to the
fibers having a standard electrochemical reduction potential less than the
standard
electrochemical reduction potential of the metal to which the composite mass
is
attached. The mass of metallic fibers may include aluminum fibers, zinc
fibers,
magnesium fibers, or any combination thereof; and/or the fibers may be at
least
partially coated with aluminum, zinc, magnesium, or any combination thereof.
The
mass of metallic fibers includes a plurality of fibers that are in the form of
a ribbon.
For example, the metallic fibers may have two or more surfaces that are
generally
flat; the metallic fibers may have a cross-section transverse to the long
direction of
the fibers that includes a generally straight side; the cross-section of the
metallic fiber
may be generally polygonal (e.g, generally rectangular); the metallic fibers
may have
a cross-section including a width and a thickness, wherein the ratio of the
width and
the thickness is from about 20:1 to about 1:1.
[0013] The resulting composite material may exhibit excellent properties
rendering it
suitable as a substitute for steel in many applications. For example. The
composite
mass may be bonded sufficiently to any metal layer so that upon being
subjected to
peel testing under. DIN 11339, the composite exhibits a substantial amount of
cohesive failure (e.g., more than about 25%, such as at least about 40%, 50%,
60%
or higher cohesive failure). The composite mass is bonded sufficiently to any
metal
layer so that upon being subjected to lap shear testing under DIN 11465, the
composite exhibits a substantial amount of cohesive failure (e.g., more than
about
25%, such as at least about 40%, 50%, 60% or higher cohesive failure).
[0014] It can be seen from the.above that one of the unique and unexpected
features
of the present invention is that excellent bond strength is attained, and such
good
resistance to delamination may be achievable in the absence of the use in the
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composite mass of a major amount, or even in the absence of substantial
amounts of
(e.g.. potentially up to 30%, 20%, 10%, 5% or even 1% by weight) any Polar
polymer.
Additionally, it is unexpected and surprising that such bond strength between
the
polymeric matrix composite mass is not compromised, and in fact may be
enhanced,
by the presence of the fibers within the polymeric matrix composite mass, by
the use
of a phosphatized and/or galvanized steel sheets, or both. For example, it is
believed
possible that as compared with a sandwich composite that includes polymer
without
fibers sandwiched between plain carbon, uncoated steel, a composite as
described
herein that includes the fibers and which may also include a galvanized and/or
phosphatized steel layers as the sandwiching layers, the latter could
surprisingly
achieve a 2x or even 3x increase in peel strength, such as when tested
according to
DIN 11339.
[0015] . The yield strength of a sandwich composite formed using the composite
material may be about 100 MPa or more. The tensile strength of a sandwich
composite formed using the composite material of the teachings may be about
160
MPa or more. The composite may be in the form of a sandwich composite that has
a
thickness of about 0.4 mm or more, and be such that the composite mass has a
thickness that is at least about 30% of the total thickness of the sandwich
composite.
[0016] Welded articles using the teachings herein are also possible. For
example,
the shape, size. concentration, and type of the metallic fibers is selected so
that a
weld stack consisting of the composite material of the teachings herein, and a
sheet
of galvannealed steel having approximately the same thickness as the light
weight
composite, may exhibits a static contact resistance of 0.0020 0 or less, as
measured
using a compressive force of about 500 lbs applied by two axially aligned,
electrodes
each having a face diameter of about 4.8 mm electrodes: By way of further
example,
the shape, size, concentration, and type of the metallic fibers may be
selected so that
the light weight composite has a static contact resistance ratio of about 0.01
or more.
wherein the static contact resistance ratio is the ratio of: (i) the static
contact
resistance of a first weld stack consisting of the composite material of any
of claims 1
through 23 and a sheet of steel having approximately the same thickness as the
light
weight composite, to (ii) the static contact resistance of a second weld slack
consisting of two sheets of the same steel as in the first weld stack, wherein
the static
contact resistance is measured using a compressive force of about 500 lbs
(about
2224 Nt) applied by two axially aligned electrodes each having a face diameter
of
about 4.8 mm electrodes.
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[0017] The teachings herein also envision methods of making articles, which
may
include plastically deforming the composite material of the teachings to a
draw ratio
of at least about 1.5 (e.g., by way of a stamping operation). welding the
composite
material (e.g., using the same welding conditions as are conventionally
employed for
welding two bodies of conventional hot dipped galvanized steel without the
need for
employing special welding parameters), or both. The teachings also contemplate
articles employing the composite materials of the teachings and/or made from
the
methods of the teachings. Use of the materials and articles in or as part of
an
automotive vehicle component is contemplated as well.
[0018] Other attributes of the composite materials of the teachings may
include one
or more of the following. The flexural modulus of the composite material may
be at
least about 200 GPa as measured according to ASTM 0790. The concentration of
the filled polymeric layer is sufficiently, high so that the density of the
composite
material is about 0.8 d or less, where dm is the weighted average density of
any
metal sheet employed in combination with the composite mass. A surface of any
of
the metal layers may be treated on one or more surfaces (prior to formation of
the
composite) for resisting corrosion by galvanizing, such as by an electro-
galvanizing
technique; phosphatizing so as to include a phosphate containing layer;
electrostatically coating; or any combination.
[0019] The metallic fibers may be formed from scrap and/or or starting
material
derived from either or both of the first or second metal layer (e.g., shredded
strips of
scrap or shredded strips of starting material, which may or may not have .a
coating on
it); or the metallic fibers may include steel fibers and fibers of another
metal having a
melting temperature lower than the melting temperature of the steel fibers.
[0020] When two or more polymers are employed, one of the polymers may have a
tensile modulus, as measured according to ASTM 0638, that is about 25% or more
different from the tensile modulus of another polymer. One polymer may have a
rate
of water absorption, as measured by ASTM D570 that is about 25% or more
different
from the rate of water absorption of another polymer. One polymer may have a
heat
deflection temperature as measured according to ASTM D648 that is about 5 "C
or
more different from the heat distortion temperature of another polymer. One or
more
polymer may be substantially free of oxygen and nitrogen atoms. One or more
polymer may include a total concentration of oxygen and nitrogen atoms, based
on
the total weight percent of the polymer that is less than the total
concentration of
oxygen and nitrogen atoms in the other polymer.
[0021] At least one of the polymers employed may be a polyamide. At least one
of
the polymers employed may be an ionomer. At least one of the polymers may be a
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co-polymer. The ratio of tensile modulus as between two of the polymers may be
1.25:1 or higher. The weight or volume ratio of one polymer to the other may
range
from about 10:90 to about 90:10. One of the polymers may include a grafted
polyolefin, e.g., a polyolef in grafted with maleic anhydride.
[0022] The teaching herein further contemplate that composites may be further
characterized by one or any combination of the following features: the light
weight
composite may have a static contact resistance of 0,0017 Cl.or less; the light
weight
composite may have a static contact resistance of about 0.0015 0 or less; the
light
weight composite may have a static contact resistance greater than the static
contact
resistance of galvanized steel of the same thickness; the light weight
composite may
have a static contact resistance that is at least 100% greater than the static
contact
resistance of galvanized steel having the same thickness; the light weight
composite
may have a static contact resistance that is at least 200% greater than the
static
contact resistance of galvanized steel having the same thickness; the light
weight
composite may have a static contact resistance that is at least 400% greater
than the
static contact resistance of galvanized steel having the same thickness. the
light
weight composite may have a static contact resistance of about 0.0001 0 or
more;
the light weight composite may have a current range of about 1.5 kA or more;
the
light weight composite have a current range of about 2.1 kA or more; the light
weight
composite has a current range of about 2.1 kA or more; the light weight
composite
may have a current range of about 2.5 kA or more; fight weight composite may
have
a current range greater than the current range of steel of the same thickness;
the
light weight composite may have a current range at least about 0.5 kA greater
than
the current range of steel of the same thickness; the light weight composite
may have
a current range at least about 1.0 kA greater than the current range of steel
of the
same thickness.
[0023] The concentration of the metallic fibers may be from about 10 volume
percent
to about 25 volume percent, based on the total volume of the filled polymeric
material: the concentration of the metallic fibers may be from about 12 volume
percent to about 23 volume percent, based on the total volume of the filled
polymeric
material; the metallic fibers may have an average cross-sectional area of
about
0.0009 mm2 or more, wherein the cross-sectional area is measured in the
direction
perpendicular to the length of the fibers; the metallic fibers may have an
average
cross-sectional area of about 0.0025 mm a or more, wherein the cross-sectional
area
is measured in the direction perpendicular to the length of the fibers; the
metallic
fibers may have a generally rectangular cross-section in the direction
perpendicular
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to the length of the fibers; or the rectangular cross-section is characterized
by a
thickness and a width that at least as long as the thickness, wherein the
ratio of the
width to the thickness is about 20 or less.
[00241 It yet another aspect the teachings contemplate a process comprising
the
steps of: I) applying pressure to a weld stack; ii) applying an initial weld
current to the
weld stack while the pressure is applied, wherein the initial weld current is
about 0.8
kA or less; iii) incrementally increasing or continuously ramping the welding
current "
for an upslope time until the weld current reaches a second weld current;
wherein the
second weld current is at least about 0.5 kA higher than the first weld
current, and
the upslope time is about 0.01 seconds or more; wherein the weld stack
includes a
component that includes a composite material, and one or more additional
components each including at least one metal layer; wherein the composite
material
includes two Metal layers; and .one or more polymeric layers at least
partially
interposed between the two Metal layers, the polymeric layer includes one or
more
polymers, the polymeric layer includes one or more metallic fibers, and the
total
volume of the one or more polymeric layer is about 30% or more of the total
volume
of the composite material. Preferably, the process includes a step of holding
the weld
current at the second weld current for at least 0.06 seconds.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1A illustrates ,a composite material having a polymeric layer arid
a
metallic layer.
[00261 FIG. 1B illustrates a composite material having a polymeric core layer
interposed between two metallic layers.
[0027] FIG. 2 is a diagram of an illustrative process for monitoring a
polymeric
material or a composite material.
[0028] FIG. 3 is a micrograph of illustrative metallic fibers that may be
employed in
the core layer.
[0029] FIG 4. is a micrograph of an illustrative core layer including metallic
fibers and
a polymer.
[0030] FIG. 5 is a micrograph of an illustrative light weight composite
including two
metal layers, metallic fibers, and a polymer.
[0031] FIG. 6 is a curve showing the relationship between the weld button size
(in
units of mm) and the weld current (in units of kA) for a light weight
composite material
welded to galvannealed metal having a weld current range of more than 2.0 kA
(e.g.,
about 3.0 kA).
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[0032] FIG. 7 is a graph showing the relationship between the weld button size
(in
units of mm) and the weld current (in units of kA) for a light weight
compoSite
rnaterial welded to uncoated deep drawing quality steel having a weld current
range of about 2.0 kA, or more (e.g., about 2.8 kA).
[0033] FIG: 8 is a graph showing the relationship between the weld button size
(in
units of mm) and the weld current (in units of kA) for a light weight
composite material
welded to galvannealed metal having a weld current range of about 1.5 kA, or
more
(e.g., about 1.7 kA).
[0034] FIG. 9 is a graph showing the relationship between the weld button size
(in
units of mm) and the weld current (in units of kA) for a light weight
composite material
welded to hot dipped galvanized coated metal having a weld current range of
about
1.5 kA, of more (e.g., about 2.0 kA).
DETAILED DESCRIPTION
[0035] In general, the materials herein employ a tilled polymeric material, as
will be
described, and particularly one that includes a metal fiber phase distributed'
in a
polymeric matrix. In general, the composite materials herein employ at least
two
layers, one of which is the above filled (e.g., fiber-filled) polymeric
material (e.g,, in a
fiber-filled polymeric layer). More particularly, the materials herein are
composites
that include a sandwich structure, pursuant to which a fiber-filled polymeric
layer is
sandwiched between two or more other layers. The materials herein also
contemplate sandwich structure pre-cursors, e.g., a first layer upon which a
filled
polymeric layer is attached so that the filled polymeric layer has an exposed
outer
surface. A second layer may subsequently be attached to the filled polymeric
layer.
The invention also contemplates feedstock compositions (e.g., in the form of a
pellet,
a sheet, or otherwise) that include a fiber-filled polymeric material in
accordance with
the present teachings. As will be illustrated, the materials herein exhibit a
unique,
= surprising, and attractive combination of properties, which render the
materials
suitable for deforming operations (e.g., relatively high strain rate forming
operations,
such as stamping), welding operations, or both. For instance, as will be seen
from
the teachings, the filled polymeric layer is designed in a manner such that is
multiphasic. At least one phase (e.g., the filler) provides a conductive flow
path, and
is such that it is plastically deformable, and may even strain harden when
subjected
to a stress that induces plastic deformation. In addition, the polymeric phase
is such
that it bonds sufficiently to another material (e.g., a metal layer such as a
steel sheet)
that processing of the composite materials for welding and/or deforming (e.g.,
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forming, such as by stamping), will be free of delamination of the composite.
The
polymeric phase may also be such that it withstands degradation when subjected
to
coating Operations (e.g., when subjected to chemical, baths such as -
electrostatic
coating baths, or other baths for imparting corrosion resistance, common in
sheet
metal coating operations).
[0036j Composite materials of the present invention, despite including a
polymer
having generally poor electrical conductivity, may have surprisingly good
weldability
using electrical resistance weldability. For example the process window for
obtaining
an acceptable weld may be generally wide. As used herein, an acceptable weld
may
be a weld that has a button size diameter that is about 95% or more of the
diameter
of the electrode use to make the weld. As described herein, the composite
material
may even have a broader processing window for welding than steel (e.g.,
galvannealed steel) of the same thickness.
[0037J The present invention in its various aspects makes use of unique
combinations of materials to derive an attractive composite, and particularly
a
laminate composite. The laminate may be drawn (e.g., deep drawn), welded, or
both,
in a manner similar to conventional art-disclosed sheet materials, such as
sheet
metal (e.g.. stainless and/or low carbon steel) In general, the invention
makes use of
a multi-phase composite material in which the materials are selected and
employed
so that, as a whole, they impart drawability, weldability, or both.
Additionally, the
materials are such that the resulting laminates can be processed in a manner
similar
to conventional art-disclosed thin walled structures particularly as it
relates to
processes for imparting a decorative or functional surface treatment (e.g., a
coating,
a plating, or otherwise).
[00381 For example, a particular preferred combination of materials herein may
include two layers that flank a core material, the latter of which is
preferably a filled
polymeric material. The filled polymeric material preferably includes at least
one
polymer, which polymer may include, cOnsist essentially of, or consist
entirely of a
thermoplastic polymer, or otherwise has characteristics that render it
generally
processable as a thermoplastic polymer. The filled polymeric material
preferably also
includes a filler phase. and preferably a phase having a filler that includes,
consists
essentially of, or consists entirely of a fiber phase, and particularly an
elongated fiber
phase, such as an elongated metal fiber phase. .Such phase may be sufficiently
positioned and/or distributed (e.g., wrapped, braided, aligned, entangled, or
any
combination thereof), and used in sufficient volume that an electrically
conductive
network across at least portions of the filled polymeric material is realized
even lithe
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polymer itself generally is not conductive. A particularly preferred elongated
fibrous
phase may also itself exhibit elongation (either or both individual fibers or
the mass
as a whole) and possibly strain hardening.
[0039] It should be appreciated that references to "layers" herein do r not
necessarily
require discrete and separate pieces of material. For example, a layered
composite
may still be within the teachings herein if it includes a single sheet of a
material that
has been folded over upon itself to define two layers of the material, albeit
sharing a
common edge, between which is located the filled.polymeric material.
[0040] Turning now with more particularity to the teachings herein, it is seen
that in a
first aspect there is contemplated a composite material, that is made from
layers of
adjoining dissimilar materials, which includes at least one layer (e.g., a
metal layer
such as a metal face layer) and at least one polymeric layer, the composite
being
formable (e.g., stampable by application of a stress to cause plastic strain
(e.g., at a
relatively rapid rate) of the material or otherwise capable of being cold-
formed on a
press machine) into a formed panel. The composite material may be a composite
laminate containing one metallic layer and one polymeric layer, or it may
include one
or more other layers. For example, it may be a laminate including one metallic
layer
interposed between two polymeric layers, or a laminate including a polymeric
layer =
sandwiched between at least two opposing metallic layers. As indicated, a
particularly preferred approach envisions this latter structure, the former
structures
possibly serving as precursors for the later structure. In such instance the
method of
forming a sandwich structure may include a step of applying a layer to a
precursor to
form a sandwich structure, a step of applying a first precursor to a second
precursor
to form a sandwich structure, or both.
[0041] An example of a composite laminate 10 having one metallic layer 14 and
one
polymeric layer 16 is illustrated in FIG. 1A. A sandwich 12 may contain a
first metallic
layer 14, a second metallic layer 14' and a polymeric layer 16 (e.g., a
polymeric core
layer) interposed between the first and second metallic layers, as illustrated
in FIG.
16. Referring to FIGs 1A and 18, the polymeric layer 16 includes at least one
polymer (e.g., a thermoplastic polymer) 18 and a fiber 20. The polymeric layer
16 and
the first metallic layer 14 may have a common surface 22. As illustrated in
FIGs. 1A
and 1B some or all of the fibers may have a length and orientation such that
they
extend from one surface of the polymeric layer to the opposing surface of the
polymeric layer. However, it will be appreciated that other fiber lengths and
orientations are within the scope of the inventions. For example, the fraction
of the
fibers (e.g., metallic fibers) that extend between the two opposing faces of
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polymeric layer may be less than 20%, less than 10%, less than 5%, or less
than 1%.
The fibers illustrated in FIGs. 1A and 18 are generally straight fibers. It
will be
appreciated from the teachings herein that preferred fibers are generally not
straight.
Preferred fibers have one or More bends along a length of the fiber, have a
generally
curved profile, or both.
[0042] As mentioned, in addition to the composite, multi-layered structures,
another
aspect of the invention contemplates a precursor polymeric layer sheet
material (i.e.,
a single layer of the polymeric layer) including the thermoplastic polymer and
the
fiber (e.g., metallic fiber), that can be later sandwiched between two
metallic layers.
[0043] Yet another aspect of the invention contemplates. a precursor polymeric
feedstock material containing the polymer and the fibers. Such a polymeric
feedstock
material may be formed (e.g., molded or extruded) into the polymeriCilayer
(e.g., into
a sheet) either as a single material or by diluting with one or more
additional
materials (e.g, one or more additional polymers) As such, the precursor
polymeric
feedstock material may include some or all of the components in the polymeric
layer
of the composite material. Preferably, the precursor polymeric feedstock
material
includes substantially all of the fiber for the polymeric layer.
[0044] In use, the composites may be deformed (e.g., formed, such as by
stamping),
attached to another structure (e.g., to steel or td another composite
material), or both.
A preferred approach is to employ a step of welding the composite of the
invention to
the other structure. The formed panel may be joined to other parts, when
necessary,
by techniques other than welding, such as by using adhesives, a brazing
process, or
the like. In both cases, the composite material (e.g., the laminate or
sandwich sheet)
is formable by low-cost stamping methods and yet is surprisingly free of the
limitations that have been faced previously in the art. The unique features of
the
composite material render it an extremely attractive candidate for
applications which
traditionally utilize a regular monolithic metal sheet, such as in the body
panels
currently employed in the transportation (e.g., automotive) industry,
[0045] One unique feature of the invention is that it includes specific
selection of the
polymer (e.g., thermoplastic polymer) and the metal fibers, and incorporation
of metal
fibers and optional particles, as well as other optional fillers, into the
polymeric matrix
to produce a novel formable composite material (e.g. sandwich or laminate
structure)
for low-cost stamping operation. Another novelty is that the stampable
sandwiches
can be joined by conventional welding techniques such as resistance welding
(e.g.,
spot welding, seam welding, flash welding, projection welding, or upset
welding),
energy beam welding (e.g., laser beam, electron beam, or laser hybrid
welding), gas
=
welding (e.g., oxyfuel welding, using a gas such as oxyacetylene), arc welding
(e.g.,
gas metal arc welding, metal inert gas welding, or shielded metal arc
welding).
Preferred joining techniques include high speed welding techniques such as
resistance spot welding and laser welding.
[0046] Various features of forrnable/stampable materials such test methods,
test
criteria, descriptions of defects, and descriptions of forming processes are
described
in the following publications:
M. Weiss, M. E. Dingle, B. F. Rolfe, and P. D. Hodgson, "The Influence of
Temperature on the Forming Behavior of Metal/Polymer 'Laminates in Sheet Metal
Forming", Journal of Engineering Materials and Technology, October 2007,
Volume
129, Issue 4, pp. 530-537.
D. Mohr and G. Straza, -Development of Formable All-Metal Sandwich Sheets for
Automotive Applications", Advanced Engineering Materials, Volume 7 No. 4,
2005.
pp. 243-246,
J. K. Kim and T. X. Yu, 'Forming And Failure Behaviour Of Coated, Laminated
And
Sandwiched Sheet Metals: A Review", Journal of Materials Processing
Technology,
Volume 63, No1-3, 1997, pp. 33-42.
K.J. Kim, D. Kim, S.H. Choi, K. Chung, K.S. Shin, F. Barlat, K.H. Oh, J.R.
Youn,
"Formability of AA5182/polypropylene/AA5182 Sandwich Sheet, Journal of
Materials
Processing Technology, Volume 139, Number 1,20 August 2003 'pp. 1-7.
Trevor William Clyne and Athina Markaki U.S. Patent Number 6,764,772 (filed
Oct
31, 2001. issued Jul 20,2004).
Frank Gissinger and Thierry Gheysens, U.S. Patent Number 5,347,099, Filed Mar
4,
1993, Issued Sep 13, 1994, "Method And Device For The Electric VVelding Of
Sheets
Of Multilayer Structure".
Straza George C P, International Patent Application Publication (PCT):
W02007062061, 'Formed Metal Core Sandwich Structure And Method And System
For Making Same", Publication date: May 31, 2007.
Haward R. N., Strain Hardening of Thermoplastics, Macromolecules 1993,26, 5860-
5869.
International Patent Application Publication No. W02010/021899 published on
February 25, 2010 by Mizrahi,
U.S. Patent Application No. 61/290,354 (filed on December 28, 2009 by
Mizrahi).
U.S. Patent Application No. 61/089,704 (filed on August 18, 2008 by Mizrahl).
U.S. Patent Application No. 61/181,511 (filed on May 27, 2009 by Mizrahi).
U.S. Patent Application Publication No. US2010/0040902A1, published on
February
13
CA 2842609 2019-01-11
18, 2010, by Mizrahi.
MATERIALS
100471 By way of example, the use of a fibrous filler in the polymeric layer
is believed
to facilitate composite manufacturing and surprisingly low levels may be
employed to
achieve the beneficial .results herein, Surprisingly, the selection and
combination of
materials taught herein affords the ability to employ less meter per unit
volume than
conventional metal structures of like form (e.g., sheet metal) while still
exhibiting
comparable properties and characteristics. The problem that the skilled
artisan might
envision in such a combination of materials unexpectedly are avoided. In this
regard,
some of the behavioral characteristics of the materials that might be
predicted are
surprisingly avoided, are employed advantageously in the resulting composite,
or
both. The resulting laminates thus render themselves as attractive candidates
to be a
drop-in substitute for existing materials, for example, they can be employed
instead
of sheet steel, without the need for significant investment in resources to re-
tool or
significantly alter processing conditions.
POLYMERIC LAYER
[00481 The polymeric layer generally may include or even consist essentially
of a
filled polymer, (e.g., a thermoplastic polymer filled with a reinforcing
fiber, such as a
metallic fiber). As such it is generally a filled polymeric material composite
mass,
which has a polymeric matrix and a mass of fiber distributed throughout the
matrix,
100491 The filled polymeric material for use in the polymeric layer preferably
is one
that generally would be characterized as being relatively rigid, relatively
strong, have
a relatively high elongation at break, have high strain hardening properties,
is light
weight, or any combination thereof, such as described in International Patent
Application Publication No. W02010/021899 published on February 25, 2010 by
Mizrahi
[0050] Preferably, at least .Sorne of the polymer in the filled polymeric
material is a
thermoplastic, but it may be or include a thermoset polymer, particularly a
thermoset
polymer that is processable as a thermosplastic, but cured. Preferably, at
least 50%
(more preferably at least 60%, 70%, 80%, 90% or even 95%, if not 100%) by
weight
of the polymer used in the filled polymeric material is a thermoplastic
polymer
(00511 The filled polymeric material may have electrical conductivity
properties (e.g.,
the filled polymeric material may be an electrical conductor) such that a
conductive
path is provided through the filled polymer and the composite material may be
14
CA 2 842 60 9 2 01 9-01 ¨11
welded to another structure such as a sheet metal The electrical conductivity
properties of the polymeric core material may be achieved by employing
metallic
fibers and optionally metallic or carbon black particles that are dispersed in
the
polymer in a quantity to have at least a percolation concentration, such as
described
in International Patent Application Publication No. W02010/021899 published on
February 25, 2010 by Mizrahi. The filled polymeric material and the composite
materials of the present teachings may be weldable using art-disclosed weld
schedules or with other weld schedules as described International Patent
Application
Publication No. W02010/021899 published on February 25, 2010 by Mizrahi. For
example, the materials may allow for more economical weld schedules that are
faster, require less energy, or both.
[00521 The filled polymeric material (e.g., the polymer of the filled
polymeric material)
may additionally include one or more additives known to the polymer
compounding
art, such as described in International Patent Application Publication No.
W02010/021899 published on February 25, 2010 by Mizrahi. For example, the
filled
polymeric material may Include halogenated flame retardant compounds disclosed
in
U.S. Pat. Nos: 3,784,509 (Dotson at. al., January 8, 1974, see for example the
substituted imides described in column 1, line 59 through column 4, line 64),
3,868,368 (Dotson et al. February 25, 1975, see for example the halogenated
bisimides described. in column 1, line 23 through column 3, line 39);
3,903,109
(Dotson et al. September 2, 1975, see for example the substituted imides
described
in column 1, line 46 through column 4, line 50); 3,915,930 (Dotson et al.
October 28,
1975, see for example halogenated bisirnides described in column 1, line 27
through
column 3, line 40); and 3,953,397 (Dotson et al. April 27, 1976, see for
example the
reaction products of a brominated imide and a benzoyl chloride described in
column
1', line 4 through column 2, line 28)
(0053] The filled polymeric material may be free of a plasticizer or other
relatively low
molecular weight materials which may become volatilized (e.g., during a
resistance
welding process). If employed, the concentration of plasticizer or other
relatively low
molecular weight materials preferably is less than about 3 wt. %, more
preferably
less than about 0.5 wt. %, and most preferably less than about 0.1 wt. % based
on
the total weight of the filled polymeric material (e.g., such that the filled
polymeric
material does not delaminate from a metallic layer).
[0054] It is also possible the teachings herein contemplate a step of
selecting
materials, processing conditions, or both, so that during processing,
delamination of
Is
CA 2842609 2019-01-11
the filled polymeric material from the metallic layer is substantially, or
entirely avoided
(e.g., delaminalion caused by vapor pressure buildup at an Interface between
the
filled polymeric material and the metallic layer sufficient for causing
delamination).
=
POLYMERS
[0055] With more attention now to particular examples of polymers for use
herein,
the polymers used for the filled polymeric material preferably include
thermoplastic
polymers that either have a peak melting temperature (as measured according to
ASTM D3418-08) or a glass transition temperature (as measured according to
ASTM
034.18-08) greater than about 50 C (preferably greater than about 80 C, even
more
preferably greater than about 100 C, even more preferably greater than about
120 C, more preferably greater than about 160 C, evert more preferably greater
than
180 C, and most preferably greater than about 205 C). The thermoplastic
polymer
may have a peak melting temperature, a glass transition temperature, or both
that is
less than about 300 C, less than about 250 C, less than about 150 C, or even
less
than about 100 C. They may be at least partially crystalline at room
temperature or
substantially entirely glassy at room temperature. Suitable polymers- (e.g.,
suitable
thermoplastic polymers) may be characterized by one or any combination of the
following tensile properties (measured according to ASTM D638-08 at a nominal
strain rate of 0.1 s''); a tensile modulus (e.g., Young's Modulus) greater
than about
30 MPa, (e.g., greater than about 750 MPa, or greater than about 950 MPa): an
engineering tensile strength (i.e., a,,), a true tensile strength (i.e., crõ
where a, =
(14-e0)o. where r., is the engineering strain), or both, greater than about 8
MPa (e.g.,
greater than about 25 MPa, greater than about 50 MPa, or even greater than
about
80 MPa); or a plastic extension at break or elongation at failure of at least
about 20%
(e.g., at least about 50%, at least about 90%, or even at least about 300%).
Unless
otherwise specified, the term tensile strength refers to engineering tensile
strength.
(0056) The polymer may preferably have ,strain hardening properties (e.g., a
relatively high strain hardening modulus, a relatively low extrapolated yield
stress, or
both), such as described in International Patent Application Publication No.
W02010/021899 published on February 25, 2010 by Mizrahi. As such, the strain
hardening properties may be measured using the method of Haward R. N., Strain
Hardening of Thermoplastics, Macromolecules 1993, 26, 5860-5869.
[0057] Examples of thermoplastic polymers which may be used for the polymeric.
layer include polyolefins (e.g. polyethylene (such as linear low density
polyethylene)
16
CA 2842609 2019-01-11
and polypropylene), acetal copolymers, polyamides, polyamide copolymers,
polyim ides, polyesters (e.g., 'polyethylene terephthalates and polybutylene
terephthalate), polycarbonates, thermoplastic polyurethanes, thermoplastic
polyether-ester copolymers (such as a thermoplastic elastomer ether-ester
material
described in ASTM D 6835-08, acrylonitrile
butadiene styrene copolymers, polystyrenes, copolymers including at least 60
wt. %
of an o-olefin and at least one additional monomer (such as an ethylene
copolymers
including at least 80 wt. % ethylene), copolymers including any of these
polymers,
ionomers including any of these polymers, blends of any of these polymers, or
any
combination thereof. As can he appreciated from the above description, one or
more
polymers may be an elastomer, such as a thermoplastic elastomer.
10058] The filled polymeric material preferably includes, or consists
essentially of one
or more polymers having sufficient adhesion to metal so that the polymer
adheres to
the metallic fibers, a metal layer, or both. For example, the filled polymeric
material
may include, or consist essentially of one or more polymers having a
sufficient.
concentration of polar groups so that the polymer adheres to the metallic
fibers, the
metal layer, or both.
100591 Of course, as the teachings elsewhere support, it is also surprisingly
possible
that a generally non-polar group containing polymer may be employed as a
predominant polymeric component and satisfactory adhesion results obtained, In
particular, it is possible that good resistance to delamination may be
achievable in
the absence of the use in the composite mass of a major amount, or even in the
absence of substantial amounts of (e.g., potentially up to 30%, 20%, 10%. 5%
or
even 1% by weight) any polar polymer.
[00601 Additionally, it is unexpected and surprising that such bond strength
between
the polymeric matrix composite mass is not compromised, and in fact may be
enhanced, by the presence of the fibers within the polymeric matrix composite
mass,
by the use of a phosphatized and/or galvanized steel sheets, or both. For
example, it
is believed possible that as compared with a sandwich composite that includes
polymer without fibers sandwiched between plain carbon, uncoated steel, a
composite as described herein that includes the fibers and which may also
include a
galvanized and/or phosphatized steel layers as the sandwiching layers, the
latter
could surprisingly achieve a 2x or even 3x increase in peel strength, such as
when
tested according to DIN 11339, Such results may be possible by employing a
polymer having polar groups, a polymer that does not include polar groups or
both.
= One approach is to employ a mixture of a thermoplastic polymer (e.g., a
polyolefin,
17
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such as a linear low density polyethylene) and an elastomer (e.g., a
thermoplastic
elastorner, such as an ethylene-containing co-polymer), an ionorner, or both.
[00611 The filled polymeric material may include, consist of or consist
essentially of
one or more generally ductile polymers (e.g., an elastomer, such as a
thermoplastic
elastomer). that are ductile when impacted at low temperatures (e.g., at a
temperature of about -30 C, at a temperature of about -40 C, or both) so
that
composite material can be stamped in a high speed stamping operation, so that
the
composite material does not fracture when impacted at -30 C or -40 C, or
both. By
way of example, the generally ductile polymers include polymers having a glass
transition temperature of about -25 C or less, about -30 'C or less, about -
35 C or
less, about -40 C or less, or about -45 C or less. Without limitation, the
glass
temperature of the generally ductile polymer may be about -100 C or more. The
ductile polymer may be a semi-crystalline polymer having a crystallinity of
about 90
wt. % or less, about 80 wt. % or less, about 70 wt. % or less, about 60 wt. %
or less,
about 50 wt. % or less, or about 40 wt. % or less. Such polymers may be
characterized as having a high tensile elongation, preferably about 50% or
more,
more preferably about 80% or more, and most preferably about 110% or more, as
measured by ASTM D638.
(0062] As discussed herein, in various aspects of the invention, the composite
material is subjected to one or more electrical resistance welding operations.
It will be
appreciated that such welding operations may produce high temperatures near
the
weld that may degrade polymer into low molecular weight compounds (i.e..
compounds that volatilize at a temperature of about 200 C, or at about 300
C),
cause low molecular weight compounds to volatize (possibly exerting an
internal
pressure in the composite that may result in delamination), or both. As such,
the
polymer may be selected so that it does significantly degrade during a welding
operation to produce low molecular weight compounds. The polymer may be
selected so that the concentration of low molecular weight compounds, if any,
is
sufficiently low so that the filled polymeric material does not delaminate
from a metal
layer during a resistance welding operation. Furthermore, the composite
material
preferably is substantially free of, or even entirely free of polymers or
other
compounds that when heated in a welding operation produce compounds that can
degrade metal, such as the metal of the metal layer.
[0063] Preferred polymers reduce or prevent corrosion of the metallic fibers,
the
metal layers or both, particularly in environments that are humid (e.g., about
90%
relative humidity, about 95% relative humidity, or more), hot (e.g., about 25
C, about
18
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40 'C, or about 60 C), corrosive (e.g., a mist of salt water containing about
5 wt. J.
sodium chloride), or any combination thereof. For example, the polymer may
adhere
to the metal and prevent water from contacting the surface of the metal. As
such, the
filled polymeric composition may include, or consist essentially of one or
more
polymer having an equilibrium water concentration (e.g., measured at about 25
C, at
a relative humidity of about 90 %) of about 8 wt. % or less, preferably about
3 wt. %
or less, more preferably about 1 wt. % or less, even more preferably about 0.2
wt. %
or less, and most preferably about 0.05 wt. % or less. The filled polymeric
material
may be substantially free of, or even entirely free of polymer that corrodes
metal. la
polymer that corrodes metal is employed, the polymer is preferably compounded
with
one, or more additives, one or more additional polymers, or both, so that
metal
corrosion is reduced or substantially prevented.
[0064] A single thermoplastic polymer may provide one or more desirable
characteristics for the filled thermoplastic composition or the light weight
composite
material, such as those characteristics described herein. As such, the
thermoplastic
polymer may consist essentially of a single thermoplastic polymer. However, it
may
be desirable to use a blend or mixture of thermoplastic polymers, or even to
employ a
plurality of layers containing one or more different thermoplastic polymers
for
achieving one or more of the characteristics, for reducing the cost, or both.
The filled
thermoplastic composition may include at least i) a first thermoplastic
polymer and ii)
a second thermoplastic polymer that is different from the first thermoplastic
polymer.
For example, the filled thermoplastic composition may include a first
thermoplastic
polymer and a second thermoplastic polymer having one or any combination of
the
following characteristics: the first thermoplastic polymers may have one or
more
oxygen atoms, one or more nitrogen atoms, or both; the second thermoplastic
polymer may be substantially free of oxygen and nitrogen atoms; the second
thermoplastic polymer may include a total concentration of oxygen and nitrogen
atoms, based on the total weight percent of the polymer that is less than the
total
concentration of oxygen and nitrogen atoms in the first thermoplastic polymer
(preferably the difference between total concentration of oxygen and nitrogen
atoms
in the first thermoplastic polymer and the second thermoplastic polymer is
about 2 wt
% or more, more preferably about 4 wt. % or more, even more preferably about
10
wt. % or more, and most preferably about 20 wt. A3 or more). The second
thermoplastic polymer may have a tensile modulus, as measured according to
ASTM
D638, that is about 15% or more different (preferably about 25% or more
different,
more preferably about 50% or more different, and most preferably about 70% or
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more different) from the tensile modulus of the first thermoplastic polymer.
The
second thermoplastic polymer may have a rate of water absorption, as measured
by
ASTM D570 that is about 15% or more different (preferably about 25% or more
different, more preferably about 50% or more different, and most preferably
about
70% or more different) from the rate of water absorption of the first
thermoplastic
polymer. The second thermoplastic may a softening point such as a heat
deflection
temperature as measured according to ASTM D648 that is about 5 C or more
different (preferably about 15 C or more different, more preferably about 25
C or
more different, even more preferably about 35 C or more different, and most
preferably about 50 C or more different) from the heat distortion temperature
of the
first thermoplastic polymer. Surprisingly, such mixtures including a first
thermoplastic
polymer and a second thermoplastic polymer may result in materials having
properties that are not found in a single thermoplastic polymer.
[00651 Preferable polyolefins for use in any of the embodiments herein include
polypropylene homopolymers (e.g., isotactic polypropylene homopolymer),
polypropylene copolymers (e.g., random polypropylene copolymers, impact
polypropylene copolymer, or other polypropylene copolymer containing isotactic
polypropylene), polyethylene homopolymer (e.g., high density polyethylene, or
other
polyethylene having a density greater than about 0.94 g/orn5; linear low
density
polyethylene (e.g., having a density below that of a high density
polyethylene, such
as below about 0.93 g/cm3) or otherwise), polyethylene copolymers (e.g.,
preferably
including at least about 60% ethylene, more preferably at least 80 wt. %
ethylene), a
blend of any of these polymers, or any combination thereof. Polypropylene
homopolymers and polypropylene copolymers may be substantially tree of atactic
polypropylene. If present, the concentration of atactic polypropylene in the
polypropylene preferably is less than about 10 wt. %. Suitable polypropylene
copolymers and polyethylene copolymers include copolymers that consist
essentially
of (e.g., at least 98% by weight), or consist entirely of one or more a-
olefins. Other
polypropylene copolymers and polyethylene copolymers that may be used include
copolymers containing one or more comonorners selected from the group
consisting
acrylates. vinyl acetate, acrylic acids, or any combination thereof. The
concentration
of the comonomer may be less than about 40 wt. %, preferably less than about
25
%, more preferably less than about 20 wt. %, and most preferably less than
about
15 wt. % based on the total weight of the copolymer. Exemplary polyethylene
copolymers that may be used include ethylene-co-vinyl acetate (i.e., "EVA",
for
example containing less than about 20 wt. % vinyl acetate), ethylene-co-methyl
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acrylate (i.e., EMA), ethylene co-methacrylic acid, or any combination
thereof.
[0066] Polyamides generally are polymers having one or more repeating units
that
includes an amide groups along the backbone of the polymer chain. For example,
polyamides may be a reaction products of a diamine and a diacid, Other
examples of
polyamides include monadic polyamides. Generally, monadic polyamides are
formed
by a ring opening reaction. Exemplary polyamides which are formed from a
diamine
and a diacid may include polyamides (e.g., polyamides) containing reaction
products
of either adipic acid or terephthalic acid with a diamine. Exemplary monadic
polyamides include polyamide 6, and poly(p-benzamide). The polyamide may be a
homopolymer, a copolymer. or a mixture thereof. Preferred polyamide
homopolyrners
which may be used in the present invention include polyamide 3, polyamide 4,
polyamide 5, polyamide 6, polyamide 6T, polyamide 66, polyamide 610, polyamide
612, polyamide 69, polyamide 7, polyamide 77, polyamide 8, polyamide 9,
polyamide
10, polyamide 11, polyarnide 12, and polyamide 91. Copolymers containing any
of
the above mentioned polyamides may also be used. Polyamide copolymers may be
random copolyrners, block copolymers, a combination thereof, Examples of
polyamide copolymers include polymers having a plurality of different amides
(i.e., a
polyamide-polyamide copolymers). polyesteramide copolymers,
polyetheresteramide
copolymers, polycarbonate-ester amides, or any combination thereof,
[00671 A polyamide-polyamide copolymer may include two or more of the
polyamides described herein for a polyamide homopolymer. Preferred polyamide-
poiyamide copolymers include, polyamide 6 and polyamide 66, polyamide 610, or
any combination thereof. For example, a polyamide-polyamide copolymer may
consist essentially of two or more pelyamides selected from the group
consisting of
polyamide 6, polyamide 66, polyamide 69, polyamide 610, polyamide 612, and
polyamide 12. More preferably the polyamide-polyamide copolymer consists
essentially of two or more polyamildes selected from the group consisting of
polyamide 6, polyamide 66. polyamide 69, and polyamide 610. Examples of such
copolymers include polyamide 6/66, polyamide 6/69, and polyamide 6/66/610. A
particularly preferred polyamide-polyarnide copolymer is a polyamide 6/66
copolymer. The concentration of polyamide 66 in the polyamide 6/66 copolymer
may
be about 90 weight percent or less, preferably about 70 weight percent or
less, more
preferably about 60 weight percent or less, and most preferably about 50
weight
percent or less, based on the total weight of the copolymer. The concentration
of
polyamide 6 in the polyamide 6/66 copolymer may be about 10 weight percent or
more, preferably about 30 weight percent or more, more preferably about 40
weight
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percent or more, and most preferably about 50 weight percent or more, based on
the
'total weight of the copolymer. Another particularly preferred polyamide-
polyamide
copolymer is a random or block copolymer of a polyamide 6 and polyamide 69.
Polyamide copolymers (i.e., a copolymer including one or more amide monomers)
may include a polyether, such as an aliphatic ether or an aromatic ether.
[0068] If employed, a polyamide copolymer may be used alone or as a mixture
with
one or more additional thermoplastics. The polyamide copolymer may be a block
copolymer, a random copolymer, an alternating copolymer, a graft copolymer, or
any
combination thereof. Without limitation, the polyamide copolymer may, include
polyamide 6, polyamide 6,9, or both. For example the polyamide copolymer may
be a
copolymer include polyamide 6 at a concentration of about 1 wt. % or more,
preferably about 5 wt. % or more, more preferably about 10 wt. "A or more and
most
preferably about 20 wt. % or more. If employed, the concentration of the
polyamide 6
in the copolymer may be about 99 wt. % or less, preferably about 95 wt. % or
less,
even more preferably about 90 wt. % or less and most preferably about 80 wt. %
or
less. The polyamide copolymer may be a copolymer include polyamide 6,9 at a
concentration of about 1 wt. % or more, preferably about 5 wt. % or more, more
preferably about 10 wt. % or more and most preferably about 20 wt % or more.
If
employed, the concentration of the polyamide 6,9 in the copolymer may be about
99
wt. % or less, preferably about 95 wt. % or less, even more preferably about
90 wt. %
or less and most preferably about 80 wt. % or less. A particularly preferred
polyamide
copolymer includes or consists essentially of polyamide 6 and polyamide 6,9.
The
polyamide copolymer may be blended with one or more polyamide homopolymers.
Without limitation, polyamide homopolymers that may be employed include or
consist
essentially of polyamide 6, polyamide 6,6, polyamide 6,9, or any combination
thereof.
Such a blend may have a sufficient amount of polyamide copolymer so that the
filled
polymeric layer has good toughness, good formability, or both. Such a blend
may
have a sufficient amount of polyamide homopolymer so that the filled polymeric
material has a high heat deflection temperature, a generally low cost, or
bOth. The
weight ratio of the polyamide homopolymer to the polyamide copolymer may be
about 1:99 or more, about 5:95 or more, about 10:90 or more, about 30:70 or
more,
or about 50:50 or more. The weight ratio of the polyamide homopolymer to the
polyamide copolymer may be about 99:1 or less, about 95:1 or less, about 90:10
or
less, about 80:20 or less, or about 70:30 or less. A particularly preferred
blend of
polyamide homopolymer and polyamide copolymer is a blend of polyamide 6 and
polyamide 6/6,9 copolymer (e.g., at a ratio of about 30:70 to about 70:30).
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[00691 Polyethers which may be used in a polyamide copolymer may be formed by
the polymerization of a diet, such as a glycol (e.g., with one or more
additional
monomers). Exemplary glycols which may be used include propylene glycol,
ethylene glycol, tetramethylene glycol, butylene glycol, or any combination
thereof.
Any of the above copolymers may be a block copolymer including a relatively
soft
block and a relatively hard block. The ratio of the elastic modulus of the
relatively
hard block to the relatively hard block may be greater than about. 1.1,
preferably
greater than about 2, and more preferably greater than about 10. The
relatively hard
block may include or consist essentially of one or more aromatic amides, one
or
more semi-aromatic amides, or one or more aliphatic amides. The relatively
soft
block may include a polyester, such as a polyester described above (e.g., an
aliphatic polyester), a polycarbonate (e.g., an 'aliphatic polycarbonate), a
polyether
(e.g., an aliphatic polyether), or any combination thereof. Amide copolymers
may
include a first monomer (e.g., a first amide monomer) and a second monomer,
each
both independently having a concentration greater than about 5 wt. %,
preferably
greater than about 20 wt. %, more preferably greater than about 30 wt. % and
most
preferably greater than about 40 wt. %, based on the total weight of the
copolymer.
The concentration of the first monomer. the second monomer, or both
independently
may be less than about 95 wt. %, preferably less than about 80 wt. %, more
preferably less than about 70 wt. %, and most preferably less than about 60
wt. %
based on the total weight of the copolymer. The combined concentration of the
first
monomer and the second monomer may be greater than about 50 wt. %. preferably
greater than about 75 wt. %, more preferably greater than 90 wt. %, and most
preferably greater than about 95 wt. % based on the total weight of the
copolymer.
[0070] The polyamide copolymer may be characterized as a thermoplastic
elastomer, having a relatively low melting temperature, a relatively low
elastic
modulus, or both. For example, the copolymer may have a relatively low melting
temperature compared to the highest melting temperature of any of the
homopolymer
consisting essentially of one of the monomers of the copolymer. For example,
the
copolymer may have a relatively tow elastic modulus compared to the highest
elastic
modulus of any of homopolymer consisting essentially of one of the monomers of
the
copolymer. Preferred polyamide copolymers or other polymeric materials for use
herein may be characterized by a melting point less than about 220 C
(preferably
less than about 190 C, more preferably less than about 170 C, and most
preferably
less than about 150 C) as measured according to ASTM D3418-08; a melting point
greater than about 60 C (preferably greater than about 80 C, more preferably
greater
23
than about 100 C, and most preferably less than about 110 C) as measured
according to ASTM 03416-06; .an elastic modulus less than about 2.5 GPa
(preferably less than about 1.2 GPa, more preferably less than about 800 MPa,
and
most preferably less than about 500 MPa), as measured according to ASTM D638-
08; an elastic modulus greater than about 50 MPa (preferably greater than
about 100
MPa, and more preferably greater than about 200 MPa), as measured according to
ASTM D638-08, a strain at break greater than about 50% (preferably greater
than
about 90%, more preferably greater than about 300%), as measured according to
ASTM 0638-08; or any combination thereof.
[0071) The teachings herein may employ a combination of two or more polymers,
at
least one of which may be a polyolef in, such as a linear low-density
polyethylene.
The polymer may be capable of exhibiting an ultimate tensile strength of at
least
about 50 MPa, more preferably at least about 60 MPa (per ASTM 0882-10), and
.ultimate elongation (per ASTM .D882-10) of at least about 500%, and more
preferably
at least about 600%. Examples of commercially available polyoletins may
include
FliFORto LI74104, from Westlake Chemical; DowlexTm 2553, 2045G, 2517, from The
Dow Chemical Company; Equistar PetrotheneT" Select GS710060; MarFlex 7109
from Chevron Phillips; or SABICTm LLDPE 726 Series, from SABIC.
[0072) Suitable ionomers mixtures of an ionic compound and a copolymer
including
a polar monomer and a nonpolar monomer. Suitable non-polar monomers that may
be used in the copolymer of an ionomer include a-olefins, such as a-olefins
having
from 2 to about 20 carbon atoms (e.g., from about 2 to about 8 carbon atoms).
Exemplary nonpolar monomers that may be employed in a copolymer (with or
without an ionorner) herein include ethylene, propylene, 1-butene, 1-hexene,
and 1-
octane, or any combination thereof. Suitable polar monomers include monomers
which upon polymerization have an ionic group. Without limitation, examples of
polar
monomers that may be employed in a copolymer (with or without an ionomer)
herein
include acids, such as acids having from about 2 to about 20 carbon atoms
(e.g..
methacrylic acid, ethacrylic acid. The concentration of the polar monomer in
any
copolymer herein (with or without an ionomer) may be less than about 40 wt. %,
preferably less than about 25 wt. 9/0, and more preferably less than about 20
wt. %,
based on the total weight of the ionomer. The concentration of the polar
monomer in
the ionomer may be about 1 wt. % or more, about 2 wt. % or more, about 3 wt. %
or
more, about 5 wt. % or more, about 7 M. 9/. or more, or about 10 wt. % or
more.
Suitable ionic compounds for any ionomer herein may include compounds
containing
one or more alkali earth metals, one or more alkaline earth metals, or both.
Without
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limitation, the ionic compound may include sodium, potassium, lithium,
calcium,
magnesium, or any combination thereof. Particularly preferred ionic compounds
include sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium
hydroxide. By way of example, commercially available ionorners include SURLYNO
poly(ethylene-co-methacrylic acid) ionomer and NAFIONO perfluorosulfonate
ionomers. An example of a generally non-polar polymer that may be employed
herein
(e.g., alone or as part of a mixture of polymers) is an ethylene-octene
copolymer. A
suitable non-polar polymer may have an ultimate tensile strength (MPa), per
ASTM
D638-08 of at least about about 7.5 and more preferably at least about 9.0, an
ultimate tensile elongation (%) per ASTM D638-08 of at least about 700, and
more
Preferably at least about 800, a flexural modulus .(MPa) per ASTM 0790-_10 (1%
secant) of at least about 13, and more preferably at least about 15 and (2%
secant)
of at least about 12 and more preferably at least about 14. Example of
possible
commercially available polymers may include Tafmer A-0550S from Mitsui
Chemicals, Exact TM 9071 from ExxonMobil, EngageTM 8150 from The Dow Chemical
Company, or Infuse T" 9007 from The Dow Chemical Company.
[0073] It employed, an ionomer or non-polar polymer as described above may be
used alone or as a mixture with one or more additional polymers, such as one
or
more additional thermoplastics. For example, the ionomer may be used in a
mixture
including one or more polyolef ins.
100741 Exemplary polyolefins that may be employed in any of the embodiments
herein or that optionally may be mixed with an ionomer include homopolymers
and
copolymers including about 50 wt. % or more of an a-olefin having about 2 to
about
carbons. Preferred polyolefins for mixing with an ionomer include those having
about 50 wt. "Yo or more of ethylene, propylene, butane, or hexane. More
preferred
polyolefins for mixing with an ionomer include those having about 50 wt. % or
more
of ethylene, or propylene. The concentration of the a-olefin (e.g., the
concentration of
the ethylene or propylene) in the polyolefin preferably is about 60 wt. % or
more,
more preferably about 70 wt. % or more, even more preferably 'about 80 wt. %
or
more, and most preferably about 90 wt. % or more, based on the total weight of
the
polyolefin. Preferred polyolefins include polyolefins consisting essentially
of one or
more a-olefins. For example, the concentration of the one or more a-olefins
may be
about 90 wt. c'/0 or more, about 95 wt. % or more, about 98 wt. % or more,
about 99
wt. % or more, or about 99.9 wt. % or more, based on the total weight of the
polyolef in. Without limitation,, the polyolef in used in a blend with an
ionomer may
include or consist essentially of high density polyethylene (e.g., having a
density of
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about 0.945 to about 0.990 Wan), low density polyethylene, linear low density
polyethylene (e.g., a copolymer having a density of about 0.915 to about 0.930
g/cm3), medium density polyethylene (e.g., a copolymer having a density of
about
0.930 to about 0.945 g/cm3), very low density polyethylene (e.g., having a
density of
about 0.900 to about 0.915 gtcm3), polyethylene plastomers (e.g., a copolymer
having a density of about 0.860 to about 0.900 g/cm3, preferably from about
0.870 to
about 0.895 Wee), isotactic polypropylene homopolyrner, isotactic
polypropylene
copolymers having a crystallinity of about 5 wt. % or more, impact
polypropylene,
polypropylene block copolymers including one or more blocks of isotactic
polypropylene, mixtures thereof, or any combination thereof. =
[0075] Examples of other polyolefins suitable for use herein, such as for
optional
blending or other mixing with another polymer (e.g., with an elastomer, an
ionomer,
or otherwise) are copolymers including or consisting essentially of ft about
60 wt. %
or more of an ceolefin; and, ii) one or more monomers selected from the group
consisting of vinyl acetate, 'methyl acrylate, butyl acrylate, acrylic acid,
methyl
methacrylate, methacrylic acid, and any combination thereof. The mixture of an
ionomer and a polyolefin may include a sufficient amount of the ionomer so
that the
polymer adheres to the metal layers, to the metallic fiber, or both. The
weight ratio of
the ionomer to the polyolef in may be about 1:99 or more, about 3:97 or more,
about
5:95 or more, about 10:90 or more, or about 20:80 or more. The weight ratio of
the
ionomer to the polyolefin may be about 99:1 or less, about 90:10 or less,
about 70:30
or less, about 50:50 or less, or about 40:60 or less.
[0076) Suitable polyurethanes include thermoplastics formed from polymerizing
one
or more diisocyanates and one or more diols. Preferred polyurethanes include
thermoplastic formed from polymerizing one or more diisocyanates and two or
more
diols. The polyurethane may be a thermoplastic polyurethane elastomer, such as
one
including a first polymer block containing a first diol and a second polymer
block than
includes a second diol, where the first block is a relatively hard block
(e.g., having a
relatively high modulus) and the second block is a relatively soft block
(e.g., having a
modulus lower than the relatively hard block). The concentrations of the
relatively
hard block and the relatively soft block may each independently be greater
than
about 5 wt. ,,e, preferably greater than about 10 wt. "Ye, and more
preferably greater
than about 20 wt. % based on the total weight of the copolymer. The
concentrations
of the relatively hard block and the relatively soft block may each
independently be
less than about 95 wt. %, preferably less than about 90 wt. %, and more
preferably
less than about 20 wt. % based on the total weight of the copolymer. The total
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concentration of the relatively hard block and the relatively soft block may
be greater
than about 60 wt. %, preferably greater than about 80 wt. %, more preferably
greater
than about 95 wt. 5/0, and most preferably greater than about 98 wt. % based
on the
total weight of the polymer, Commercially available thermoplastic
polyurethanes
(TPU) that may be employed include ESTANE brand TPU available from Lubrizol
Corporation, ELASTOLAN brand TPU available form BASF and DESMOPANO
brand TPU available from Bayer. =
10077] Tho thermoplastic polymers are preferably relatively long chain
polymers,
such that they may have a number average molecular weight greater than about
20,000, preferably greater than about 60,000, and most preferably greater than
about
140,000. They may be unplasticized, plasticized, elastomer modified, or free
of
elastomer. Semi-crystalline polymers may have a degree of crystallinity
greater than
about 10 wt%, more preferably greater than about 20 wt%, more preferably
greater
than about 35 wt%, more preferably greater than about 45 wt%, and most
preferably
greater than about 55 wt%. Semi-crystalline polymers may have a degree of
crystallinity less than about 90 wt%, preferably less than about ,85 wt%, more
preferably less than about 80 wt%, and Most preferably less than about 68 wt%.
Crystallinity of the thermoplastic polymer may be measured using differential
scanning calorirnetry by measuring the heat of fusion and comparing it to art
known
heat of fusion for the specific polymer.
[0078] The polymer of the filled polymeric material may also contain up to
about 10
wt% of a grafted polymer (e.g., a grafted polyolefin such as isotactic
polypropylene
hornopolyrrier or copolymer, or a polyethylene homopolymer or copolymer) which
is
grafted with a polar molecule, such as maleic anhydride. The concentraton of
the
grafted compound may be about 0.01 wt. % or more based on the total weight of
the
grafted polymer. Particularly preferred grafted polymers include from about
0.1 wt. %
to about 3 vvt. % maleic anhydride.
[0079] The thermoplastic polymer may include a substantially amorphous polymer
(e.g., a polymer having a crystallinity less than about 10 wt. %, preferably
less than
about 5 wt: %, and most preferably less than about 1 wt. %, as measured by
differential scanning calorimetry at a rate of about 10 C/mm). For example,
the
thermoplastic polymer may include a substantially amorphous polymer having a
glass transition temperature greater than 50 C, preferably greater than 120 C,
more
preferably greater than about 160 C, even more preferably greater than about
180 C, and most preferably greater than about 205 C, as measured by dynamic
mechanical analysis at a rate of about 1 Hz. Exemplary amorphous polymers
include
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polystyrene containing polymers, polycarbonate containing polymers,
acrylonitrile
containing polymers, and combinations thereof:
[0080] Without limitation, examples of styrene containing copolymers that may
be
employed in the filled polymeric material are described in International
Patent
Application Publication No. W02010/021899 published on February 25, 2010 by
Mizrahi.
[0081] As appreciated from the teachings herein, in lieu of or in addition to
any
thermoplastic polymer, the polymeric layer may employ an elastomer having one
or
both of the following properties: a relatively low tensile modulus at 100%
elongation
(e.g.. less than about 3 MPa, preferably less than about 2 MPa), a relatively
high
tensile elongation at break (e.g., greater than about 110%, preferably greater
than
about 150%) both measured according to ASTM D638-08 at a nominal strain fate
of
about 0.1 s-1. Examples of elastomers that may be employed, are described in
- International Patent Application Publication No. W02010/021899 published on
February 25, 2010 by Mizrahi.
[0082] It is possible that one or more polymers may be employed in any of the
embodiments of the teachings herein that are crosslinkable or crosslinked.
They may
be be thermoset materials or monomers, or other precursors of thermoset
materials.
They may be epoxy based, rubbers, urethane, or some other suitable material.
One
or more other agents may be employed for allowing crosslinking (and
crosslinking
may be employed) in response to a stimulus, such as heat, radiation (e.g.,
ultraviolet
and/or infrared radiation), moisture or any combination thereof.
[0083] Though it is possible that some amounts of epoxy may be used, the
polymer
of the filled polymeric material preferably is substantially free or entirely
free of epoxy,
or other brittle polymers (e.g., polymers having an elongation at failure of
less than
about 20% as measured according to ASTM D638-08 at a nominal strain rate of
about 0.1 s''), or both. If present, the concentration of epoxy, other brittle
polymers,
or both is preferably less than about 20%, more preferably less than about
10%,
more preferably less than about 5%, and most preferably less than about 2% by
volume, based on the total volume of the filled polymeric material.
[0084] In one particularly preferred aspect of the invention the filled
polymeric
material includes a one or more polyamide copolymers, one or more
thermoplastic
polyurethanes, one or more thermoplastic polyether-ester copolymers, one or
more
ionomers, or any combination thereof. The polyamide copolymer may be any of
the
polyamide copolymers described above herein. Preferred polyamide copolymers
include polyamide-polyamide copolymers, polyesteramide copolymers,
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polyetheresteramides, polycarbonate-esteramide copolymers, or any combination
thereof. Any of the thermoplastics may be a random copolymer or a block
copolymer.
Any of the thermoplastics may be a thermoplastic elastomer. By way of example,
the
filled polymeric material may include a polyester amide thermoplastic
elastomer, a
polyetheresteramide thermoplastic elastomer, a polycarbonate-esteramide
thermoplastic elastomer, a polyether-ester thermoplastic elastomer. a amide
block
copolymer thermoplastic elastomer, or any combination thereof. The filled
polymeric
material may optionally include one or more polymers that is not a copolymer.
For
example filled polymeric material may include one or more polyamide
homopolymer.
Particularly preferred polyamide homopolymers include polyamide 6 and
polyamide
6,6. If employed the concentration of the one or more polyamide homopolymers
preferably is relatively low (e.g., compared with the concentration of the one
or more
copolymers. It present, the concentration of the one or more polyamide
homopolymers preferably is about 50 weight percent or less, more preferably
about
40 weight percent or less, even more preferably about 30 weight percent or
less, and
most preferably about 25 weight percent or less, based on the total weight of
the
polymer in the filled polymeric material.
[0085] Filled polymeric materials that include a generally polar polymer may
have
sufficient attraction between the polar polymer and the metallic fibers so
that there is
no need for a functionalized polymer to improve the adhesion between the
thermoplastic and the metallic fibers. As such, the filled polymeric material
may be
substantially free of. or even entirely free of polymers having maleic
anhydride,
acrylic acid, an acrylate, an acetate, or any combination thereof. For
example. the
filled polymeric may be substantially free, or entirely free of maleic grafted
polymers.
If employed, the concentration of polymers having maleic anhydride, acrylic
acid, an
acrylate, an acetate, or any combination in the filled polymeric material
preferably is
about 20 weight percent or less, more preferably about 10 weight percent or
less,
even more preferably about 5 weight percent or less, even more preferably
about 1
weight percent or less, and most preferably about 0.1 weight percent or less,
based
on the total weight of the polymer in the filled polymeric material. By way of
example,
generally polar polymers include acetal homopolymers or copolymers, polyamide
homopolymers or copolymers, polyimide homopolymers or copolymers, polyester
homopolymers or copolymers, polycarbonate homopolymers or copolymers, and any
combination thereof. Filled polymeric materials that include a generally polar
polymer
may be substantially free of, or entirely free of polyolefin homopolymers and
copolymers including about 50 weight percent of one or more olefins. If
employed,
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the total concentration of any polyolef in homopolymers and any copolymers
including
about 50 weight percent of one or more olefins may be about 30 weight percent
or
less, preferably about 20 weight percent or less,. more preferably about 10
weigh
percent or less, even more preferably about 5 weight percent or lesS, and most
preferably about 1 weight percent or less, based on the total weight of the
polymers
in the filled polymeric material.
[0086] The life cycle use of the composite material may include a step of
heating the
composite material to a temperature sufficiently high so that the metal can be
reclaimed. As such, the polymer may be heated to a temperature at which it
burns or
otherwise thermally degrades. Preferred polymers for use in the composite
material
include polymers that do not form toxic compounds (e.g., toxic gases and/or
carcinogenic compounds) during combustion or thermal decomposition (e.g., at a
temperature of about 600 C or more).
FILLERS
[00871 The filled polymeric material (e.g., the filled thermoplastic polymeric
layer)
contains one or more fillers. The tillers may be a reinforcing filler, such as
fibers, and
more particularly metallic fibers. Metallic fillers (e.g., metallic fibers)
that may be
employed are described in International Patent Application Publication No.
W02010/021899 published on February 25, 2010 by Mizrahi. For example, metallic
fibers which may be used in the invention include fibers formed from metals
such as
steel (e.g., low carbon steel, stainless steel, and the like), aluminum,
magnesium,
titanium, copper, alloys containing at least 40 wt% copper, other alloys
containing at
least 40 wt% iron, other alloys containing at least 40 wt% aluminum, other
alloys
containing at least 40 wt% titanium, and any combination thereof. The metallic
fibers
may include or consist essentially of carbon steel, such as a steel that has
about 10
wt, c'to or less chromium, about 7 wt. % or less chromium, or about 3 wt. % or
less
chromium.
[0088] The metallic fibers may have a melting or liguidus-temperature
sufficiently low
so that during a step of welding (such as electrical resistance spot welding),
some or
all of the metallic fibers in the region between the weld tips at least
partially melt
(e.gõ entirely melt) before one or both of the metallic layers melt. The
electrical
resistivity of the filled polymeric material may be higher (e.g., about 10
times higher,
or even about 100 times higher) than the electrical resistivity of the metal
layer, so
that the metallic fibers begin to melt before the metal layer begins to melt.
The
welding process may employ a step of sufficiently cooling the weld tips so
that the
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metallic fibers melts before the metal layer begins to melt. As such, the
metallic fibers
may include or consist essentially of a metal (e.g., a steel) having a melting
temperature or liquidus temperature less than, the same as, or even greater
than the
steel in the first metallic layer, the second metallic layer, or both.
[0089] The filled polymeric material may contain non-metallic conductive
fibers, such
as those described in International Patent Application Publication No.
W02010/021899 published on February 25, 2010 by Mizrahi.
[0090] The metallic fibers or other fillers employed in the filled polymeric
material
preferably are capable of reducing or eliminating the corrosion of the
metallic layers.
In one approach, one or more of the metallic fibers or other fillers in the
filled
polymeric material may have a relatively high galvanic activity. For example,
the
metallic fibers or other fillers in the filled polymeric material may have a
higher
galvanic activity than the metal employed for the surface of one or preferably
both of
the metallic layers (of the composite material) in contact with or facing the
filled
polymeric material. As such, it may be desirable for the filled polymeric
material to be
substantially, or even entirely free of fillers having a low galvanic
activity. By way of
example, this approach to reducing the corrosion of a composite material may
use a
filled polymeric material that is substantially or entirety free of carbon
black. The one
or more fillers having a relatively high galvanic activity preferably have an
anodic
index that is greater than the metallic layer by about 0.05 V or more, more
preferably
by about 0.1 V or more, even more preferably by about 0.20 V or more, and most
preferably by about 0.25 V or more. The one or more fillers having a
relatively high
galvanic activity may be any art known material having a higher galvanic
activity than
the metallic layer. By way of example, such fillers may includes one or more
zinc
containing materials, one or more magnesium containing materials, one or more
aluminum containing materials, or any combination thereof. The one or more
fillers
may include a first filler and a second filler having a higher galvanic
activity than the
first filler, where the second filler is a sacrificial filler. If the filled
polymeric materials
includes a first filler and a sacrificial filler, the first filler preferably
is a metallic fiber.
The sacrificial filler may have a relatively high total surface area (i.e., of
all of the
sacrificial filler particles) compared to the surface are of the metallic
layer, the total
surface area of the first filler, or preferably both. For example, the ratio
of the total
surface are of the sacrificial filler to the surface area of the metallic
layer may be
about 1.5 or more, preferably about 3 or more, more preferably about 10 or
more,
and most preferably about 50 or more. If the filled polymeric materials
includes a first
filler and a sacrificial filler, the first filler may have a surface having a
galvanic activity
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that is less than, equal to, or greater than the galvanic activity of the
surface of the
metallic layer. If the first filler has a surface having a galvanic activity
greater than the
galvanic activity of the surface of the metallic layer, the first filler may
function as a
sacrificial filler. As such, a second sacrificial filler may not be needed and
the filled
polymeric may be substantially or entirely free of a second sacrificial
filler.
[00911 Some or all of the metallic fibers may provide cathodic protection to
one or
more metallic layer of the composite material. For example, the metallic
fibers may
include fibers formed of a material or coated with a material having a
standard
electrochemical reduction potential less than the standard electrochemical
reduction
potential of the first metallic layer, the second metallic layer, or both.
Metals having a
generally low standard electrochemical reduction potential include metals
having a
standard electrochemical reduction potential less than steel (e.g., SAE carbon
steel
1015). Metals having generally low standard electrochemical reduction
potentials
include aluminum, zinc, and magnesium. As such, some or all of the metallic
fibers
may include or consist essentially of aluminum, zinc, magnesium, an alloy
thereof, or
any combination thereof. Particularly preferred fibers for cathodic protection
are zinc
fibers. Some or all of metallic fibers may include metal (e.g., steel) that
has been
coated and/or plated, such as by a process that includes one or more steps of
electrocoating, electroplating, or both. For example, the metal may be coated
by a
step of galvanizing. A metallic fiber may be coated on one or more, or even
all of its
sides. Without limitation, a fiber may be coated by spraying, by dipping
(e.g., by hot
dipping). By way of example, a metallic fiber may be prepared from a sheet or
foil
that is coated (e.g, by spraying or dipping) on one or two surfaces and then
cut into
narrow strips or ribbons. As such, the metallic fiber may have one or two
coated
surface. As another example, the fibers may be coated after being formed into
fibers
= so that all sides of the fibers are coated. As yet another exa.rnple, a
continuous
filament may be coated and then cut into fibers so that all of the sides of
the fiber are
coated except the ends. The coating preferably includes a metal selected from
aluminum, zinc, magnesium, an alloy thereof, or any combination thereof. As
such
the metallic fibers may include one or more coating layers of a metal that
includes
aluminum, zinc, magnesium, an alloy thereof, or any combination thereof, and
one or
more substrate layers that are free of aluminum, zinc, magnesium, an alloy
thereof,
or any combination thereof. Particularly preferred coated metallic fibers
include a
coating layer having a standard electrochemical reduction potential less than
the
standard electrochemical reduction potential of the metallic layers of the
composite
material (e.g., the 'first metal layer, the second metal' layer or both).
Particularly
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preferred coated fibers are fibers that are coated with a !aye': including
zinc or a zinc
alloy.
[0092] If employed, the fibers providing cathodic protection may be provided
at a
sufficient quantity, size, surface area, or any combination thereof so that
corrosion of
the surface of the metallic layer (e.g., the surface facing the polymeric
layer) during
prolonged exposure to a corrosive environment (e.g., at about 40 C, with a
mist
spray of salt water (e.g., containing about 5 wt. % sodium chloride), for
about 200 or
more (e.g.,) hours is reduced or essentially eliminated.
[0093] The metallic fibers preferably have dimensions and distribution of
dimensions
as described in International Patent Application Publication No. W02010/021899
published on February 25, 2010. Without limitation, the metallic fibers may
have a
weight average length, L.õ0, greater than about 1 mm, more preferably greater
than
about 2 mm, and most preferably greater than about 4 mm. Suitable fibers may
have
an 1....vg of less than about 200 mm, preferably less than about 55 mm, more
preferably less than about 30 mm, and most preferably less than about 25 mm.
The
weight average diameter of the fibers may be greater than about 0.1 gm, more
preferably greater than about 1.0 gm, and most preferably greater than about 4
gm.
The weight average diameter of the fiber may be less than about 300 pm,
preferably
less than about 50 gm, even more preferably less than about 40 gm, and most
preferably less than about 30gm.
[0094] The metallic fibers may have any shape. Preferably, the metallic fibers
are
curvilinear. For example, generally linear metallic fibers may be used. More
preferably the metallic fibers are not straight fibers along the length of the
fiber. By
way of example, metallic fibers that are not straight, may have one or more
bends,
may have a generally arcuate profile, may have a generally helical shape, or
any
combination thereof. Metallic fibers that are initially straight, preferably
become fibers
that are not straight (such as described above) when combined with the
thermoplastic polymer.
[0095] The cross-section of the metallic fibers, perpendicular to the length
of the
fiber, may have any geometry. For example, the cross-section may have one or
more
sides that are generally arcuate, one or more sides that are generally
straight, or any
combination thereof. By way of example, the metallic fibers may have a cross-
section
that is elliptical, circular, polygonal, star-shaped, semi-circular, or the
like.
[00961 In one embodiment of the invention the metallic fibers preferably have
one or
more generally flat surfaces, such as a generally flat surface in the
longitudinal
direction of the fiber. Without being bound by theory, it is believed that a
metallic fiber
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having 'a generally flat surface may increase the electrical conductivity of
the filled
polymeric material and/or the light weight composite compared with a material
in
which the metallic fibers have a generally cylindrical shape. The cross-
section of a
metallic fiber, in the transverse direction of the fiber (i.e., perpendicular
to the length
of the fiber), may have one or more generally straight sides. For example, the
cross-
section of a metallic fiber in the transverse direction may have four or more
generally
straight sides, two or more parallel sides, or both. Without limitation, the
metallic fiber
may have a cross-section that is generally rectangular, generally a
parallelogram,
generally a polygonal having four or more 'sides, or generally a square. It
will be
appreciated that the metallic fiber may have a cross-section that is generally-
elliptical,
such as an ellipse having an aspect ratio of about 3 or more, preferably about
5 or
more, and more preferably about 7 or more. The cross-section of the metallic
fiber in
the transverse direction may be characterized by a width (i.e., the longest
dimension)
and a thickness (e.g., the thinnest dimension and/or the direction
perpendicular to the
width). The ratio of the width to the thickness of the fibers may be about 1
or more,
about 2 or more, or about 3 or more. The ratio of the width to the thickness
of the
fibers may be about 30 or less, about 20 or less, or about 15 or less.
Exemplary
fibers are fibers prepared by cutting a metallic foil (e.g., having a
thickness that is
about the thickness of the fibers) into narrow ribbons (e.g., the spacing
between cuts
may be the width of the fibers). It will be appreciated from the teachings
herein that
the metallic fiber t may be prepared from a monolithic metallic foil, or from
a metallic
foil having one or more coatings (e.g, a coating on both large surfaces), such
as a
coating that offers galvanic protection.
[0097] The metallic fibers have a length that is greater than the width and
the
thickness. The weight average length of the metallic fibers preferably is
about 200
pm or more, more preferably about 500 gm or more, even more preferably
about .800 um or more, and most preferably about 1 mm or more. It will be
appreciated that the metallic fibers may have a weight average length of about
1,0
rim 'or more, or even be generally continuous. For applications that require
spot
welding, the metallic fibers preferably have a weight average length that is
less than
the diameter of a weld tip typically used for spot welding, so that the
metallic fibers
may more easily flow away from the weld zone during a welding process. For
example, the metallic fibers may have a weight average length of about 20 mm
or
less, about 10 mm or less, about 7 mm or less, about 5 mm or less, about 4 mm
or
less, orabout 3 mm or less. The aspect of a fibers may be estimated by
dividing the
length of the fiber by (4A1IT1')'12, where AT is the cross-sectional area of
the fiber in the
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transverse direction. The aspect ratio of the fiber may be about 5 or more,
about 10
or more, about 20 or more, or about 50 or more. The aspect ratio of the fibers
may be
about 10,000 or less, about 1,000 or less, or about 200 or less. 11 will be
appreciated
from the teachings herein that metallic fibers having an aspect ratio greater
than
10,000 may employed.
[00981 When used in the polymeric layer between two metallic layers, the
metallic
fibers preferably are present as a mass of fibers. The mass of metallic fibers
may be
interconnected. The mass of metallic fibers may be entangled. The mass of
fibers
may form mechanical interlocks (i.e., two or more fibers may be mechanically
interlocked). The mass of metallic fibers preferably spans with thickness of
polymeric
layer so that the mass of fibers (e.g., the network of metallic fibers)
electrically
connects the two metallic layers. Although a single metallic fiber may span
the
thickness of the polymeric layer, preferably none of the metallic fibers span
the
thickness of the polymeric layer. If metallic fibers span the thickness of the
polymeric
layer, the fraction of the fibers that span the thickness preferably is about
0,4 or less,
more preferably about 0,20 or less, even more preferably about 0,10 or less,
even
more preferably about 0.04 or less, and most preferably about 0.01 or less.
The
fibers in the mass of fibers preferably are arranged in a non-ordered
arrangement.
For example, the maximum number of neighboring metallic fibers that are
arranged
in a generally aligned arrangement may be less than about 100, preferably less
than
about 50, more preferably less than about 20, even more preferably less than
about
10, and most preferably less than about 5. More preferably the mass of fibers
are
arranged in a generally random arrangement. Individual metallic fibers that
contact a
surface of one of the metallic layers preferably are free of a planar contact.
As such,
the composite material may be characterized as being essentially free, or even
entirely free of planar contacts between a metallic fiber and a metallic
layer. Fibers
that contact a metallic surface, preferably have a line contact, a point
contact, or a
combination, thereof. Some of the metallic fibers may contact one of the
metallic
layers, however few, if any of the metallic fiber will contact a metallic
layer over a
large portion of the length of the metallic fiber. As such, a large fraction
of the
metallic fibers do not contact a metallic layer or at least have a significant
portion that
is not in contact with the metallic layer. The fraction of the metallic fibers
that contact
a metallic layer along at least half of the length of the fiber is preferably
about 0.3 or
less, more preferably about 0.2 or less, even more preferably about 0.1 or
less, even
more preferably about 0.04 or less, and most preferably about 0.01 or less.
[00991 The metallic fibers are preferably sufficiently thin and present in a
sufficient
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concentration so that many fibers are arranged between the surfaces of the
layer.
For example, the average number of fibers that intersect a line parallel to
the
thickness direction of the polymeric layer and going through the polymeric
layer
preferably is about 3 or more, more preferably about 5 or more, more
preferably
about 10 or more, and most preferably about 20 or more. Without being bound by
theory, it is believed that a large number of metallic fibers advantageously
allows for
more homogeneous deformation of the material, such as during a stamping
process.
[00100] The concentration of the metallic fibers is preferably greater
than
about 1 volume%, more preferably greater than about 3 volume%, even more
preferably greater than about 5 volume%, even more preferably greater than
about 7
volume%, even more preferably greater than about 10 volume/0, and most
preferably
greater than about 12 volume% based on the total volume of the filled
polymeric
material. The metallic fibers may be present in the filled polymeric material
at a
concentration less than about 60 volume%, preferably less than about 50
volume%,
more preferably less than about 35 volume %, still more preferably less than
about
33 volume%, and most preferably less than about 30 volume% (e.g., less than
about
25 volume%, or even less than about 20, 10, or 5 volume%). For example the
amount of fiber may be about 1%, 2%, 3%, z1%, 5%, 6%. 7%, 8%, 0%, or 10%, by
volume based on the total volume of the filled polymeric material, or within a
range
bounded by those values (such as from about 1% to about 6%). It is possible
that
composites herein may employ a concentration of metallic fibers that
surprisingly is
substantially lower than the amount of a particle filler necessary to achieve
similar
welding characteristics, Moreover, it is also possible that the fibers and
materials are
selected so that better welding performance surprisingly may be realized at a
relatively low concentration of metallic fibers as compared with an identical
composite material having a higher concentration of metallic fibers. For
example, it is
surprisingly seen that using a filled polymeric material having about 10
volume %
metallic fiber results in composite materials having superior welding
characteristics
compared with those made with filled polymeric materials having higher
concentrations of metallic fiber.
1001011 The thermoplastic polymer material may be present in the filled
polymeric material at a concentration greater than about 40 volume%,
preferably
greater than about 65 volume %, more preferably greater than about 67 volume%,
still more preferably greater than about 70 volume%, and most preferably
greater
than about 75 volume% (e.g., at least about 80 volume%, at least about 90
volume
%, or even at least about 95 volume%).
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[00102] The volume ratio
of the polymer (e.g., the thermoplastic polymer) to
the fibers (e.g., the metallic fibers) is preferably greater than about 2.2:1,
more
preferably greater than about 2.5:1, and most preferably greater than about
3:1. The
volume ratio of the polymer* (e.g., the thermoplastic polymer) to the fibers
(e.g., the
metallic fibers) is preferably less than about 99:1, more preferably less than
about
33:1, even more preferably less than about 19:1, and most preferably less than
about
9:1, (e.g., less than about 7:1).
[00103] The material of
any core in the sandwich composites herein may
contain pores or voids, or may be substantially free of pores and voids.
Preferably,
the concentration of pores and voids in the filled polymeric material is less
than about
25 volume%, more preferably less than about 10 volume%, still more preferably
less
than about 5 volume%, and most preferably less than about 2 volume% (e.g.,
less
than about '1% by volume), based on the total volume of the filled polymeric
material.
[00104] The fiber (e.g.,
the conductive fiber, such as the metallic fiber)
preferably is present at a concentration greater than about 40 volume %, more
preferably greater than about 70 volume %, and most preferably greater than
about
80% (e.g., greater than about 90 volume %, or even greater than about 95
volume
%) based on the total volume of the filler in the filled polymeric material,
[00105] The combined
volume of the polymer (e.g., thermoplastic polymer)
and the metallic fibers is preferably at least about 90% by volume, more
preferably at
least about 95% by volume and most preferably at least about 98% by volume
based
on the total volume of the filled polymeric material.
[00106] The metallic
fibers provide one or any combination of electric
conductivity for welding, a reinforcement for strengthening, or strain
hardening the
polymeric structure by utilizing fibers that as metals are capable of
extending and
imparting better strain hardening properties to the polymeric core. As such,
the
tensile elongation (at failure) of the metal fibers is preferably greater than
about 5%,
more preferably greater than about 30%, and most preferably greater than about
60% as measured according to ASTM A370-03a.
[00107] It is possible
that the materials herein may employ in combination with
fibers, a metallic particle. Metallic particles may be spherical, elongated,
or of any
shape other than a fiber shape. Metallic particles which may be employed
include
those described in International Patent Application-Publication No.
W02010/021899
published on February 25, 2010.
[00108] The fibers (e.g.,
the metallic fibers) or the combination of the fibers
and the metallic particles preferably are dispersed (e.g., randomly dispersed)
in the
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polymeric matrix at a volumetric concentration of less than about 30% (more
preferably less than about 25 c'4, and most preferably less than about 20%) by
volume of the total polymeric layer). If metallic particles are employed, the
ratio of the
volume of the fibers (e.g., the metallic fibers) to the volume of the metallic
particles in
the filled polymeric material layer may be greater than about 1:30, preferably
greater
than about 1:1; and most preferably greater than about 2:1.
[00109) In one aspect of the invention, metallic particles, metallic
fibers, or
both may be obtained by a step of grinding offal and/or scrap such as
described in
International Patent Application Publication No. W02010/021899 published on
February 25, 2010 by Mizrahi. The offal and/or scrap may be derived from the
metal
sheet that is employed to make sandwich composites herein. Thus, to the extent
that
the sheet metal has been coated or otherwise treated to resist corrosion, the
offal
and/or scrap may also include such coating or treatment. The fibers thus may
be in
the form of comminuted or otherwise shredded phosphatized and/or galvanized
steel,
which may be high strength steel.
[001101 A particularly preferred metallic fiber that may be used,
optionally with
one or more other fibers, is a carbon steel having a generally rectangular
cross-
section in direction transverse to the length, a weighted average thickness of
about
to about 70 i.tm, a weighted average width of about 40 to about 200 pm, and a
weighted average length of about 0.8 to about 5 mm. Surprisingly this metallic
fiber
can be used in a composite material having an electrical conductivity in the
through-
thickness direction that is larger (e.g., by about. 50% or more, or even by
about 100%
or more) relative to an identical composite material except the fibers are
replaced by
the same weight of a stainless steel fiber having a generally cylindrical
cross-section
and a diameter of about 10 pm or less.
1001111 With reference to FIG. 3. the metallic fibers 20" may have a
cross-
section in the direction transverse to the long direction that includes one,
two or more
generally straight sides (such as a generally rectangular cross-section). The
length of
the metallic fibers may have regions that are generally straight, regions that
are
generally arcuate, or both. The metallic fibers may be sufficiently long, have
sufficient
curvature (e.g., along the length of the fibers), be present in sufficient
quantity orany
combination thereof, so that an entangled mass of fibers is formed.
[00112] FIG, 4 is an illustrative micrograph of a section of a core
layer 16
including metallic fibers 20 and a polymer 18. As illustrated in FIG. 4,
fibers may
sufficiently overlap so that an electrical current can be transferred through
the core
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layer. For example, the electrical conductivity of the core layer may be
sufficient so
that the composite material can be welded using electrical resistance welding.
[00113] FIG. 5 illustrates an edge of an illustrative composite
material
including metallic fibers 20' having a generally rectangular cross-section in
the
direction transverse to the long direction of the fibers. The core layer
includes an
entangled mass of metallic fibers 20' and a polymer 18' sandwiched between two
metallic layers 14".
[00114] As will be seen, the metallic fibers preferably are selected so
that the
composite material has generally god weld characteristics. For example, the
concentration of the metallic fibers, the size of the metallic fibers, the
amount of
contact between the metallic fibers, the shape of the metallic fibers, the
amount of
contact between a metallic fiber and the metal layers, or any combination
thereof of
may be selected so that the composite material has a generally good weld
processing window, a generally high electrical conductivity, a generally high
static
contact resistance, or any combination thereof. A generally good weld
processing
window may be characterized for example by a high weld current range, a high
weld
time range, or both.
[00115] In addition to the above fillers, one or more art-disclosed
conventional
fillers may also be employed herein in their art-disclosed proportions,
examples of
which may include talc, mica, wollastonite, nanoclays, calcium carbonate,
silicates, or
the like.
The test method for weld current range measurement
[001161 The current range for a test material can be measured by
welding a
stack consisting of a sheet of the test material and a sheet of a control
monolithic
steel (such as a sheet of galvanized steel) having the same thickness as the
sheet of
the test material. The weld may be performed using two electrodes. The
electrode
against the test material has a face diameter, d. The electrode against the
sheet of
the control steel may be equal to or greater than d. The weld time and the
weld
pressure are fixed and may be predetermined, such as from a standard weld
schedule for a material. The weld button size may be measured by separating
the
two sheets. The measurement is started by selecting a current that produces a
weld
button greater than 0.95 d. The weld current is then decreased incrementally
until the
weld button is less than d. The weld current is then increased until a poor
weld is
obtained. The minimum current that produces an acceptable weld (e.g., a weld
having a weld button size of at least 0.95 d) is the minimum weld current. At
high
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weld currents, a poor weld may be indicated by metal expulsion, sticking of a
sheet to
an electrode, a loud weld popping noise, or otherwise, or any combination
thereof.
The highest current that produces an acceptable weld is the maximum weld
current.
The weld current range is the difference between the maximum weld current and
the
initial weld current. By way of example, the weld current range may be
performed
using a composite material having a thickness of about 0.8 mm, and
galvannealed
steel sheet having a thickness of about 0.8 mm. The electrode on the composite
material may have a diameter of about 3.8 mm and the electrode on the
galvannealed steel may have a thickness of about 4.8 mm. An compressive force
of
about 610 psi may be applied. The weld conditions may include a mid frequency
DC
weld current having a frequency of about 1,000 Hz, an upslope time of about 50
miliseconds, and a weld time of about 200 miliseconds. The materials
preferably
have a width of about 25 mm and a thickness of 25 mm or 75 mm.
[00117] The weld current range for the composite material, lc, when
welded to
a sheet of monolithic steel having the same thickness as the composite
material is
preferably greater than the current range for two monolithic sheets of steel,
lm.
having the same thickness as the composite materiel. The ratio of lc to Im is
preferably about 1.1 or more, more preferably about 1.2 or more, even more
preferably about 1.3 or more, even more preferably about 1.4 or more, and most
preferably about 1.5 or more. The current range of the composite material, lc,
preferably is about 1.5 kA or more, more preferably about 1.7 kA or more, even
more
preferably about 1.9 kA or more, even more preferably about 2.1 kA or more,
even
more preferably about 2.3 kA or more, and most preferably about 2.5 kA or
more.
FIG. 6 illustrates the weld current range for a composite material having a
surprisingly high weld current range.
[00118) Test method for measuring static contact resistance ,
[00119) The static contact resistance may be measured by placing a stack
consisting of the composite sheet and a sheet of cold rolled steel having a
thickness
of about 0.8 mm between two class I - RWNA electrodes (preferably having a
face
diameter of about 4.8 mm), applying a force of about 500 psi for about 45
seconds or =
more without welding the two sheets, and measuring the average resistance of
the
weld stack for the 5 seconds following the time at which the resistance is
stable. A
stable resistance may be determined by a resistance change of less than 2% per
second, less than 1% per second, or less than 0.5% per second. Preferably, the
static contact resistance may be measured using sheets having a thickness of
about
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0.8 mm, a width of about 25 mm and a length of about 25 mm or about 75 mm.
However, sheets having other thicknesses, lengths, and widths may be employed.
[00120] The static contact resistance of the composite material
preferably is
about 0.0020 0 or less, more preferably about 0.0017 0 or less, even more
preferably about 0,0015 0 or less, even more preferably about 0.0012 Q or
less, and
most preferably about 0.0008 0 or less.
1001211 Without being bound by theory, = it is believed that having a
static
contact resistance greater than monolithic steel is useful for increasing
achieving a
high weld current range. As such, the ratio of the static contact resistance
of the
composite material to the static contact resistance of steel (e.g., cold
rolled steel,
galvanized steel, galvannealed steel, or any combination thereof) preferably
is about
1 or more, more preferably about 1.2 or more, even more preferably about 1.5
or
more, even more preferably about 2 or more, even more preferably about 3 or
more,
even more preferably about 4 or more, even more preferably about 5 or more and
most preferably about 10 or more. It will be appreciated that lithe static
contact
resistance is too high, the composite may have difficulty in passing a current
and
thus not be easily welded. As such, the ratio of the static contact resistance
of the
composite material to the static contact resistance of steel (e.g., cold
rolled steel,
galvanized steel, galvannealed steel, or any combination thereof) preferably
is about
1000 or less, more preferably about 300 or less, even more preferably about
100 or
less, even more preferably about 75 or less, and most preferably about 40 or
less.
METAL LAYERS
[00122] As discussed, it is envisioned that composites herein may employ
a
sandwich structure by which a mass of a polymeric core is flanked on opposing
sides
by spaced apart layers. For example, a structure herein may include two sheets
(e.g.,
metal sheets) that have a metal fiber reinforced polymeric core material
disposed
between the sheets and preferably in contact with the sheets. The metal layers
(e.g.,
the first metallic layer and the second metal layer) of the sandwich
construction may
be made of a suitable material (e.g., metal) in the form of foils or sheets or
other
layers having equal or unequal thickness (e.g., average thickness) across the
layer.
Each metallic layer may have a generally constant thickness or may have a
thickness
that varies. The face metal on each side may be made of materials having the
same
or different properties and be made of the same or different metals. If the
metal faces
are made of metal sheets of unequal thickness, materials having different
properties,
or materials having different metal. The composite material may have a marking
or
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other means of identifying and distinguishing the different metal faces. The
layers_
may be the same or different in composition, size (e.g., thickness, width,
volume, or
otherwise), shape, or other features, relative to each other layer. The metal
layer may
have a surface treatment for helping to resist corrosion (e.g. a coating with
zinc,
phosphorus, or both). Thus, prior to or after making a composite with the
tilled
polymeric layer, one or more metal layer may be galvanized, phosphatized or
both.
[001231 Examples of metal layers that may be employed are described in
described in International Patent Application Publication No. W02010/021899
published on February 25, 2010 by Mizrahi.
[00124] The ability to down gauge sheets of steel using high strength
steel in
panel applications, such as automotive panel applications, is generally not
limited by '
the strength of the steel, but rather by the flexural modulus of the steel.
Surprisingly,
the filled polymeric layer provides sufficient stiffness with respect to the
flexural
modulus of the composite material so that further down gauging is possible. As
such,
a particularly preferred steel for use in one or more metal layers (e.g., the
first metal
layer, the second metal layer, or both) of the composite material is a high
strength
steel. Without limitation the high strength steel may have a yield strength of
about
280 MPa or more, preferably about 280 MPa or more, more preferably about 320
MPa or more, and most preferably about 340 MPa or more. The high strength
steel
may have a yield strength of about 600 MPa or less. Without limitation the
high
strength steel may have a tensile strength of about 340 MPa or more,
preferably
about 370 MPa or more, more preferably about 400 MPa or more, even more
preferably about 430 MPa, and most preferably about 450 MPa or more. The high
strength steel may have a tensile strength of about 800 MPa or less.
[00125] The first metal layer, the second metal layer, or both may include a
sufficient amount of high strength steel so that the flexural modulus of the
composite
material is at least about 200 GPa, as measured according to ASTM D790,
wherein
the concentration of the filled polymeric layer is at sufficiently high so
that the density
of the composit material is about 0.8 dm or less, where dm is the weighted
average
density of the first metal layer and the second metal layer. Surprisingly such
composite materials may have one or both of the following characteristics a
high
yield strength of about 100 MPa or more (preferably about 120 MPa or more,
more
preferably about 140 MPa or more, even more preferably about 170 MPa or more,
even more preferably about 200 MPa or more, and most preferably about 240 MPa
or more); or a high tensile strength of about 160 MPa or more (preferably
about 200
MPa or more, more preferably about 220 MPa or more, even more preferably about
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250 MPa or more, even more preferably about 270 MPa or more, even more
Preferably about 290 MPa or more, and most preferably about 310 MPa or more).
[00126] Preferred metal layers have a generally uniform thickness so that the
properties of the composite material do not vary, such as in a periodic
pattern. For
example, the difference between the highest thickness and the lowest
thickness,
divided by the average thickness, in a 100 mm x 100 mm section of a metal
layer
may be about 20% or less, about 10% or less, or about 5% or less.
[00127] One or both of the metal faces preferably may be relatively thick,
such that
the metal face does not wrinkle, tear, or form other defects when preparing
and/or
processing the composite material. Preferably, the thickness of one or both of
the
metal faces is at least about 0.05 mm, more preferably at least about 0.10 mm,
even
more preferably at least about 0.15 mm, and most preferably at least about
0.18 mm,
The sheets may have a thickness less than about 3 mm, preferably less than
about
1.5 mm, and more preferably less than about 1 mm, and most preferably less
than
about 0.5 mm. For example, the composite material may be used in an automotive
panel requiring at least one class A or class B surface, preferably at least
one class A
surface (e.g., after a stamping step, a welding step, an electrocoating step,
a painting
step, or any combination thereof). Such a composite material may have a first
surface which is a class A surface and a second surface which is not a class A
surface. The class A surface may be the surface of a first, metal face having
a
relatively high thickness and the surface that optionally is not a class A
surface may
be the surface of a second metal face having a relatively low thickness (e.g.,
at least
about 20% or even at least about 40% less than the thickness of the first
metal face).
In general, the ratio of the thickness (e.g., average thickness) of the first
metal layer
to the thickness of the second metal layer may be from about 0.2 to about 5,
preferably from about 0.5 to about 2.0, more preferably from about 0.75 to
about 1.33
and most preferably from about 0.91 to about 1.1.
COMPOSITE MATERIAL
[00128] The composite material may be in the form of a multi-layered sheet,
e.g., a
sandwich structure including sheets of a material such as a metal that
sandwich a
core of the filled polymeric material. The sheets may have a total average
thickness
less than about 30 mm, preferably less than about 10 mm, more preferably less
than
about 4 mm and most preferably less than about 2 mm; and preferably greater
than
about 0.1 mm, more preferably greater than about 0.3 mm, and most preferably
greater than about 0,7 mm). The composite material may have a generally
uniform
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thickness or the composite material may have a thickness that varies (e.g, a
random
or periodic variation in one or more directions). For example, the variation
in the
thickness may be such that the standard deviation of the thickness is less
than about
10% of the average thickness. The standard deviation of the thickness is
preferably
less than about 5% of the average thickness, more preferably less than about
2% of
the average thickness, and most preferably less than about 1% of the average
thickness.
[001291 The thickness of the filled polymeric layer may be greater than about
10%,
20% 30%, 40%, or more of the total thickness of the composite material. The
volume
of the filled polymeric layer may be greater than about 10%, 20%, 30%, 40%, or
more of the total volume of the composite material. Preferably, greater than
50% of
the volume of the composite material will be the filled polymeric material.
The
concentration of the filled polymeric material is more preferably greater than
about 60
volume% and more preferably greater than about 70 volume% based on the total
volume of the composite material. The concentration of the filled polymeric
material is
typically less than 92 volume% based on the total volume of the composite
material;
however, higher concentrations may be used, particularly in relatively thick
composites (e.g., having a thickness greater than about 1,5 mm),
[00130] The total thickness of outer layers of a sandwich composite structure
herein
(e.g., metallic layers) may be less than about 70% of the total thickness of
the
composite material. The total thickness of metallic* layers preferably is less
than
about 50%, more preferably less than about 40% and most preferably less than
about 30% of the total thickness of the composite material. The total
thickness of the
outer layers (e.g., the metallic layers) may be greater than about 5%,
preferably
greater than about 10%, and more preferably greater than about 20% of the
total
thickness of thickness of the composite material.
[00131] The polymeric core layer preferably is in contact (direct or indirect,
such as
via a primer and/or adhesive layer) with at least a portion of the surface of
the
adjoining layers (e.g., one or more metallic layer) facing the core layer.
Preferably,
the area of contact is at least about 30%, more preferably at least about 50%,
most
preferably at least about 70% of the total area of the surface of the
adjoining layer
facing the polymeric core layer. If a primer or adhesive layer is employed,
the
thickness preferably is sufficiently low so that it does not affect the
electrical
characteristics of the composite material. If employed, the ratio of the
thickness of the
primer and/or adhesive layer to the thickness of the Polymeric core layer
preferably is
about 0.30 or less, more preferably about 0.20 or less, even more preferably
about
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0.10 or less, even more preferably about 0.05 or less, and most preferably
about
0.02 or less. Two adjacent metallic layers preferably are substantially not in
contact
with each other. If a surface of a first metallic layer contacts a second
metallic layer,
the ratio of the area of contact to the area of the surface of the first
metallic layer is
preferably about 0.3 or less, more preferably about 0.1 or less, even more
preferably
about 0.05 or less, even more preferably about 0.02 or less,' and most
preferably
about 0.01 or less.
[00132] The composite material may include a plurality of polymeric core
layers. For
example, the composite material may include one or more core layers which
includes
an adhesive such that it adheres to a metallic layer, a different core layer,
or both.
[00133] The composite material may have a relatively high stiffness to density
ratio,
such as described in described in International Patent Application Publication
No.
W02010/021899 published on February 25, 2010 by Mizrahi.
PROCESS FOR PREPARING THE FILLED
POLYMERIC LAYER AND THE COMPOSITE
[00134] The process for preparing the filled polymeric material and the
composite
material may employ a process described in International Patent Application
Publication No. W02010/021899 published on February 25, 2010 by Mizrahi.
[00135] The composite material may be prepared using a process that results in
the
filled polymeric material (e.g., core layer) being bonded to at least one
adjoining layer
(e.g., a metallic sheet) and preferably being interposed between two layers
(e.g., two
metallic layers) and bonded to one or both layers. The process may include one
or
any combination of steps of heating, cooling, deforming (e.g., forming, such
as by
stamping), or bonding, in order to arrive at a final desired article. It is
envisioned that
at least one, or even all of the adjoining layers (e.g., metallic layers) may
be provided
in the form of a rolled sheet, a forging, a casting, a formed structure, an
extruded
layer, a sintered layer, or any combination thereof.
[00136] The sheets may be heated to a temperature greater than about 90 C
(e.g.
greater than about 130 C, or greater than about 180 C). Preferably, the sheets
are
heated to a temperature greater than about Trnim where Tme is the highest
glass
transition temperature (Tg) and melting temperature (Tm) of the thermoplastic
of the
filled polymeric material. The metallic sheets, the filled polymeric material,
or both
may be heated to a maximum temperature above which the polymer (e.g., the
thermoplastic polymer) may undergo significant degradation. The thermoplastic
polymer may be heated to a temperature preferably less than about 350 C, more
preferably less than about 300 C. The heated polymer may be mixed with the
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metallic fiber, and with any additional fillers. The heated polymer (e.g.,
thermoplastic
polymer) may be extruded as a sheet layer. The sheet layer may be extruded
directly
between the metal faces, or placed between the metal faces later in the
process or in
a separate step. The process may include one or more steps of drying the
polymer
so that the concentration of water in the polymer is below a predetermined
maximum
moisture concentration. A step of drying the polymer may occur before, during,
or
after a step of heating the polymer. The process may include one or more steps
of
storing a polymer, a polymeric core layer, or a composite material in low
humidity
environment so that the concentration of water in the polymer is maintained
below a
predetermined maximum moisture concentration.
[00137] The polymeric core layer may be a homogeneous layer or may comprise a
plurality of sublayers. For example, the filled polymeric material may contain
an
adhesive layer such as described in International Patent Application
Publication No.
W02010/021899 published on February 25, 2010 by Mizrahi.
[00138] The process for fabricating the composite material may also include
one or
more steps of heating one or more metal layers, applying pressure to the
layers,
calendaring a polymer (e.g., a thermoplastic polymer or the thermoplastic
polymer
compounded with the metallic fiber and the optional fillers), and annealing
the
composite sheet (e.g., at a temperature greater than the melting temperature
of any
thermoplastic polymer in the material).
[001391 The process for preparing the filled polymeric material (e.g., a core
layer for
the sandwich composites herein) may include a step of contacting the fiber and
at
least a portion of the polymer (e.g., thermoplastic polymer), blending the
fiber and at
least a portion of the polymer, or both. The process of forming the polymeric
layer
may be a continuous process or a batch process. Preferably, the process is a
continuous process. The blending or contacting step may include heating the
polymer to a maximum temperature greater than about 90 C, greater than about
140 C, greater than about 170 C, or greater than about 190 C. The blending or
contacting step may include heating the polymer to a maximum temperature less
than about 350 C, less than about 300 C, less than about 280 C, less than
about
270 C, or less than about 250 C.
100140] Suitable process may employ one or more steps of applying pressure
when
at least some of the polymer of the filled polymeric material is at a
temperature
greater than about 80 C, preferably greater than about 120 C, more preferably
greater than about 180 C, even more preferably greater than about 210 C, and
most
preferably greater than about 230 C. The step of applying pressure may employ
a
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maximum pressure greater than about 0.01 MPa, preferably greater than about
0.1
MPa, more preferably greater than about 0.5 MPa, even more preferably greater
than
about 1 MPa, and most preferably greater than about 2 MPa. The maximum
pressure
during the step of applying pressure may be less than about 200 MPa,
preferably
less than about 100 MPa, more preferably less than about 40 MPa, and most
preferably less than about 25 MPa. The process may also include a step of
cooling
the composite material (e.g. to a temperature below Taa, preferably below the
melting temperature of polymer of the filled polymeric Material, and more
preferably
below about 50 C).
[00141] The composite material may be or include a laminate, such as described
in
International Patent Application Publication No, W02010/021899 published on
February 28. 2010 by Mizrahi.
[00142] It may desirable to prevent water (liquid, gas, or solid) from
contacting the
polymeric material so that the moisture level in the polymeric material is
low, so that
the filler in the polymeric material does not corrode, or both. As such, the
process for
preparing the composite material may include one or more steps of
substantially
protecting an edge of the composite material from contact with a liquid or
gas. For
example, a coating or protective layer may be placed over one or more (or
preferably
all) of the edges of a polymeric layer (core layer), one or more (or
preferably all) of
the edges of the composite material may be sealed, or any combination thereof.
If
employed, a coating or protective layer placed over an edge of a polymeric
layer
preferably includes one or more materials that have a relatively low
permeability to
moisture compared to the polymer of the filled polymeric material. Any
material
having relatively low permeability to moisture may be used. Without
limitation, a low
permeability material may include a layer of polyethylene vinyl alcohol or a
copolymer
thereof, a layer of a polyolefin homopolyrner, or a copolymer consisting
substantially
of one or more olefins, or any combination thereof. A coating or protective
layer may
be permanently attached to the polymeric layer, to the metallic layer or both.
Alternatively, a coating or protective layer may be used temporarily. For
example, a
coating or protective layer may be removed prior to one or more forming steps,
prior
to one or more welding steps, prior to one or more electrocoating steps, or
prior to
one or more painting steps. Any edges of the composite material may be sealed
using any art known mean that forms one or more sealed spaces between the
metallic layers. By way of example, the metallic layers may be welded together
near
an edge. The metallic layers may be welded together along the entire periphery
of
the composite material.
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[00143) One or more steps of monitoring the quality of the parts may be
employed
during or after assembly of components of the polymeric layer or the composite
material. The monitoring may be for the purpose of assuring bond integrity
between
two or more layers, assuring proper dispersion of fibers, detecting surface
abnormalities (such as cracks, blemishes, creases, roughness, and the like),
detecting voids, determining the thickness distribution (e.g., average
thickness, mean
thickness, thickness variation, minimum thickness, maximum thickness, or any
combination thereof) of one or any combination of layers of the composite, or
any
combination thereof.
[00144] One approach may include a step of monitoring the part (e.g., the
polymeric
material or the composite material) with one or more probes. The monitoring
may be
done optically (such as to detect surface defects, to determine a thickness or
thickness distribution, a temperature such as by infrared measurement, or any
combination thereof). It may be done by measuring a response of the part to
one or
more external stimulus. For example, electrical conductivity, electrical
resistivity,
impedance, or some other electrical characteristic may be measured in response
to
or more applied electrical stimulus. For example a probe may be used to
measure
the electrical characteristic at one or more location on the part
(consecutively and/or
essentially simultaneously in response to the electrical stimulus. A magnetic
characteristic may be monitored in similar manner. The stimulus may be a
magnetic
field and the response may be a mechanical response, an electrical response, a
magnetic response, or any combination thereof. The monitoring may be done
acoustically (e.g., using a probe or other source of sound waves such as
ultrasound
waves). Acoustical measurements may be employed for detecting voids, cracks,
compositional distributions, and the like.
[00145] A suitable assembly for monitoring may include a source of electricity
one
or more probes (e.g. a plurality of probes on a common carrier (possible even
an
array of probes) that essentially spans the part for assessing quality or that
is
translated over the part to obtain measurements), and at least one processor
for
receiving signals from the probes. The processor may perform an operation such
as
comparing the. signals with a predicted value range for the measured part, and
signaling when the measured value is outside of a predicted range, or
otherwise falls
within a certain predetermined range. FIG. 2_illustrates an example of such a
system.
[00146] A layered workpiece 12 of the present teachings (e.g. a laminate of
metallic
layers 14, 14' sandwiching a polymeric layer 16 containing metallic fibers) is
48
assembled. After the layers are joined a stimulus is applied (e.g., an
electrical
stimulus applied by an electrical source 102) to one or more of the metal
layers 14,
14, the polymeric layer 16, or any combination thereof. The electrical
stimulus may
be transmitted to the one or more metal layers using one or more wires 110 or
other
means of electrical communication.
[00147] One or more probes 104 may be carried by a carrier 106, and will
measure
a response of the vvorkpiece to the stimulus. The probes may be on one or both
sides
of the workpiece. The measured response may be signally transmitted to a
processor
108, which may also be in controlling or other signaling communication with
the
stimulation source. (e.g. electrical source 102).
[00148] It will be
appreciated that the monitoring process described herein
may also be used for monitoring a polymeric material (e.g., a pellet, a sheet,
or other
sample of the polymeric material).
FORMING PROCESS
[00149j The composite material of the present invention may be subjected to a
suitable forming process, such as a process that plastically deforms a
material and
may include a step of stamping, roll forming, bending, forging, punching,
stretching,
coiling, some other metalworking, or any combination thereof. A preferred
forming
process is a process that includes a step of stamping the composite material.
The
stamping process may occur at or near ambient temperatures. For example, the
temperature of the composite material during stamping may be less than about
65 C.
preferably less than about 45 C, and more preferably less than about 38 C. The
forming process may involve drawing regions of the composite material to
various
draw ratios. In one aspect of the invention, the composite material is
subjected to a
step of drawing to a relatively high draw ratio without breaking, wrinkling,
or buckling.
For example, it is subjected to a step of drawing so that at least a portion
of the
composite Is drawn to a draw ratio greater than 1.2. Desirably, the composite
material may be capable of being drawn and is drawn to a maximum draw ratio
greater than about 1.5, preferably greater than about 1.7, more preferably
greater
than about 2.1, and most preferably greater than about 2.5..The cracking limit
of the
draw ratio may be determined using the circular cup drawing test as described
by
Weiss et al. (M. Weiss, M. E. Dingle, B. F. Rolfe. and P. D. Hodgson, "The
Influence
of Temperature on the Forming Behavior of Metal/Polymer Laminates in Sheet
Metal
Forming", Journal of Engineering Materials and Technology, October 2007,
Volume
129, Issue 4, pp. 534-535) . The forming
process
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may include a step applying a pressure to a die (e.g., a die having a
hardness, as
measured according to Mehra hardness scale, greater than the hardness of the
metallic fibers) in contact with the composite material.
[00150] Suitable forming processes that may be employed Include those
described
in International Patent Application Publication No. VV02010/021899 published
on
February 25, 2010 by Mizrahi.
[00151] After forming a composite material, the process may include one or
more
steps of protecting an edge of the composite material to reduce the
penetration of
moisture into the filled polymeric material. Any of the aforementioned steps
for
protecting an edge of the composite material may be used.
CHARACTERISTICS OF COMPOSITES
[00152] The polymeric layer, the composite material, or both, may have a low
springback angle, a relatively low electrical resistivity, good weldability
(e.g., using
resistance welding), relatively low thermal conductivity, relatively low sound
transmission, or any combination thereof, such as described in International
Patent
Application Publication No. W02010/021899 published on February 25, 2010 by
Mizrahi.
[00153] Preferably, the filled thermoplastic material, the composite
material, or
both is weldable (e.g., weldable using a resistance welding technique such as
spot
welding, seam welding, flash welding, projection welding, or upset welding)
and has
a relatively low electrical resistance The teachings herein thus also
contemplate one
or more steps of welding the composite materials taught herein. The electrical
resistance of the composite material in the through-direction may be described
by the
sum of the electrical resistance of the metallic layers and the core layer.
Typically,
the electrical resistance of the metallic layers is much less than the
electrical
resistance of the core layer, such that the electrical resistance of the
composite
material may be estimated by the electrical resistance of the core layer. The
resistivity (e.g., the resistivity measured in the through-thickness
direction, normal to
the plane of a sheet) may be measured using AC modulation and determined from
the voltage drop, V, and the current, I:
Resistivity = (V/I) (Alt)
where A is the area of the sheet, and t is the thickness of the sheet. The
resistivity (in
the through-thickness direction) of the composite material, the core layer, or
both,
may be relatively low (e.g., the composite material, the core layer (e.g., the
filled
thermoplastic material), or both, may be characterized by a resistivity less
than about
100,000 a cm, preferably less than about 10,000 acm, more preferably less than
about 3,000 a cm, and most preferably less than about 1,000 acm).
1001541 The composite material may have an electrical resistivity sufficiently
low so
that the composite material is capable of being welded to a monolithic sheet
of steel
by a resistance welding technique that uses a welding schedule that is
generally the
same as the welding schedule for welding two monolithic sheets of steel of the
same
thicknesses. For example, the electrical resistivity in the through thickness
direction,
may be about 100 acm or less, preferably about 10 0.CM Or less, more
preferably
about 1 acm, even more preferably about 0.15 D=cm or less, even more
preferably
about 0.1 a cm or less, and most preferably about 0.075 aorn or less.
[001551 The composite materials may be welded using any welding process known
to one of ordinary skilled in the art of welding metals. The welding process
may
include one or more of the steps, devices, or processes described in
International
Patent Application Publication No. W02010/021899 published on February 25,
2010
by Mizrahi, U.S. Patent Application No. 611290,384 (filed on December 28, 2009
by
Mizrahl) .
100156] Preferred composite materials have a relatively good corrosion
resistance.
The composite material preferably is characterized by a rate of corrosion of a
surface
of a metallic layer facing a core layer, the core layer including a polymer
and a
metallic filler, that is lower than (more preferably at least 50% lower than)
the rate of
corrosion of a surface of a metallic layer facing a core layer of an identical
composite
material except the metallic filler in the core layer is replaced with the
polymer of the
core layer. For example, the composite material may have a rate of corrosion
of a
surface of a metallic layer facing a core layer, the core layer including a
sacrificial
filler, that is lower than the rate of corrosion of a surface of a metallic
layer facing a
core layer of an identical composite material except the sacrificial filler is
replaced
with the polymer of the core layer. The rate of corrosion In water may be
determined
= by placing samples of a composite material having predetermined
dimensions, in a
water bath at a predetermined corrosion test temperature for a predetermined
Corrosion test time, and Measuring the amount of corrosion on a surface. The
rate of
corrosion in salt water may be determined by placing samples of a composite
material having predetermined dimensions, in a salt water bath having a
predetermined salt concentration, at a predetermined corrosion test
temperature for a
predetermined corrosion test time, and measuring the amount of corrosion on a
surface. Without limitation the, corrosion test temperature may be about 40 C,
and
the corrosion test time may be about 168 hours.
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[00157] It is possible that weld joints made using various composites taught
herein
may exhibit a variation of microstructures across the composite such as
described in
International Patent Application Publication No. W02010/021899 published on
February 25, 2010 by Mizrahi.
WELDING OF COMPOSITE MATERIAL
[00158] When welding (e.g., spot welding) the composite material to one
or
more monolithic metal material (e.g., a steel material such as a steel sheet),
the
process may employ a first electrode that contacts the composite material and
a
second electrode that contacts a monolithic metal. The first electrode and the
second
electrode may be the same or different. Preferably the first electrode and the
second
electrode are different. Surprisingly, when the first electrode has a diameter
that is
less than the diameter of the second electrode, both metallic layers of the
composite
material are more easily welded to the monolithic metal material. Without
being
bound by theory, it is believed that the use of a smaller diameter electrode
to contact
the composite material results in a more balanced heat distribution, more
effectively
removes polymer from the weld zone, or both. Most preferably, the first
electrode has
a diameter that is sufficiently less than the diameter of the second
electrode, so that
the first metallic layer and the second metallic layer are both welded during
a spot
welding process. The ratio of the diameter of the second electrode to the
diameter of
the first electrode preferably is about 1.02 or more, more preferably about
1.06 or
more, even more preferably about 1.12 or more, and most preferably about 1.2
or
more. The ratio of the diameter of the second electrode to the diameter of the
first
electrode preferably is about 5 or less, more preferably about 3 or less, and
most
preferably about 2 or less.
[001591 The composite materials of the present invention preferably can
be
welded to one or more monolithic metal materials. For example, the shape,
size,
concentration, and type of the metallic fibers may selected so that the
composite
material is capable of being welded (e.g., spot welded) to steel materials
selected
from the group consisting of uncoated steel, hot dipped galvanized steel,
galvannealed steel, or any combination thereof. In particularly preferred
embodiments of the invention, the composite material has a generally high weld
current range (e.g., as described hereinbefore) for two or more different
monolithic
steel materials (e.g., two or more of uncoated steel, hot dipped galvanized
steel, or
galvannealed steel), for two or more monolithic steel materials having
different
thickness (e.g., one material having about the same thickness as the composite
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material and a second material having a thickness about 1.5 times the
thickness of
the composite material or more), or both, without the need to change the weld
time,
the electrode force, the weld time, or the weld tip size-. As such, the
composite
material may be welded to a surprisingly wide variety of materials, having a
surprisingly wide range of thicknesses without needed to change the welding
conditions. Although some changes to welding conditions may be required, the
large
weld current range allows for these changes to be greatly reduced relative to
other
materials.
[00160] By way of example, FIGs 7, 8, and 9 illustrate the measurement
of the
weld current range for a composite material of the present invention welded to
uncoated steel, galvannealed steel, and hot dipped galvanized steel
respectively.
FIG. 7, 8 and 9 are graphs showing the weld button size as a function of the
weld
current. Acceptable or good welds may be those welds which have i) a weld
button
size greater than about 95% of the weld electrode diameter ii) no expulsion of
metal;
or both. For example, when an electrode diameter of about 3.8 mm is used to
contact
the composite material, a good weld may have a weld button size of about 3.6
mm or
more. Figs. 7, 8, and 9 illustrates a composite material having a weld current
range of
about 1.5 or more (e.g., about 1.7 or more). FIG. 7 illustrates that good
welds can be
obtained with a weld current from about 6.4 kA to about 9.2 kA when welding
the
composite material to a first steel (e.g., uncoated steel). FIG. 8 illustrates
that good
welds can be obtained with a weld current from about 7.75 kA and about 9.45 kA
when welding the composite material to a .different steel (e.g., galvannealed
steel).
FIG. 9 illustrates' that good welds can be obtained with a weld current from
about
7.35 kA and about 9.35 kA when welding the composite material to another steel
(e.g., hot dipped galvanized steel). First, all three materials give generally
high weld
current ranges. Second, the overlap of, the currentsthat result in good welds
(i.e., the
overlapping weld current range) is generally high. For example, the composite
material produces good welds with these three materials from about 7.8 kA to
about
9.2 kA, and the overlapping weld current range is about 1,4 kA or more.
(001611 The composite materials of the present invention may be used in
any
number of applications requiring one or any combination of the properties
described
herein, including but not limited to relatively low density, relatively low
thermal
conductivity, relatively high stiffness to density ratio, or relatively low
acoustical
transmission. Exemplary applications which may employ the composite materials
of
the present invention may include automotive and other transportation related
applications, building construction related applications, and appliance
related
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applications. The composite materials may be used in applications such as an
automotive panel, a truck panel, a bus panel, a container (e.g., a container
used for
shipping), a panel on a train car, a panel on a jet, a tube (e.g., a bicycle -
tube), a
motorcycle panel (e.g a cowling or fairing), a trailer panel, a panel on a
recreational
vehicle, a panel on a snowmobile, an automotive bumper fascia, a spoiler, a
wheel
well liner, an aerodynamic ground effect, an air dam, a container, a bed
liner, a
divider wall, an appliance housing, a vehicle fuel filler door, a vehicle
bumper, a
decorative insert, a duct, a grab bar, a storage compartment door, a housing
for an
electronic device (such as a cellular phone, a computer, a camera, a tablet
computer,
a music or video storage device, or a music or video player), a console, an
air inlet
part, a battery housing, a grille, a wheel well, or a seat pan. The composite
materials
may be used as a building construction material, such as an exterior trim
element,
flashing, gutters, shingles, walls, flooring. countertops, cabinet facing,
window
frames, door frames, paneling, vents, ducts, planking, framing studies,
shelving,
plumbing fixtures, sinks, shower pans, tubs, and enclosures. An exemplary
application is an vehicle body panel (e.g., a body outer skin of a vehicle
such as an
automobile). Automobile panels which may use the composite materials described
herein include front quarter panels, rear quarter panels, door panels, hood
panels,
roof panels, or otherwise. The automotive panel may have a class A, class B,
or
class C surface, preferably a class A or class B surface, and more preferably
a class
A surface. The composite materials herein may also include one or more
decorative
outer surfaces or veneers, such as a metal veneer, a wood veneer, a polymeric
veneer, or otherwise. The outer surface may have a different texture, color
or. other
appearance as an opposing layer. For example, a ferrous outer layer may be
colored
so that it simulates a copper color, a bronze color, a brass color, a gold
color, or
some other color.
[00162] The composite materials of the present invention may be used in a
process that includes a step of coating the composite material, such as an
electrocoating process, a paint process, a powder coat process, any
combination
thereof, or the like, If employed, the coating process may include one or more
steps
of cleaning or otherwise preparing the surface, one or more steps of heating
or .
baking the coating (e.g., at a temperature greater than about 1 00 C,
preferably
greater than about .120 C), or any combination thereof. The coating may be
applied
by any conventional means, such as by a dipping process, a spraying process,
or
with a process employing an applicator such as a roller or a brush. As such,
the
composite material preferably is free of ingredients (e.g., low molecular
weight
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ingredients) that leach out and contaminate a bath of a coating process, such
as a
bath of an electrocoat process. Likewise, methods herein include one or more
coating steps that are free of bath contamination due to an ingredient of the
composite.
[00163] The composite material (e.g., a stamped part formed of the
composite
material) may be used in an assembly which requires joining the composite
material
to one or more other materials or parts. For example the composite material
may be
mechanically joined to another part using a fastener, or chemically joined to
another
part using an adhesive, an adhesion promoter (e.g., a primer), or both. Other
means
of joining include welding, brazing, and soldering. One or any combination of
these
joining methods may be employed.
[00164] As discussed previously, high integrity laminates that are
resistant to
delamination in service are possible in accordance with the teachings herein.
The
resulting composite material may exhibit excellent properties rendering it
suitable as
a substitute for steel in many applications. For example, the composite mass
may be
bonded sufficiently to any metal layer so that upon being subjected to peel
testing
under DIN 11339, the composite exhibits a substantial amount of cohesive
failure
(e.g., more than about 25%, such as at least about 40%, 50%, 60% or higher
cohesive failure). The composite mass is bonded sufficiently to any metal
layer so
that upon being subjected to lap shear testing under DIN 11465, the composite
exhibits a substantial amount of cohesive failure (e.g., more than about 25%,
such as
at least about 40%, 50%, 60% or higher cohesive failure). As will be
appreciated
reference to cohesive failure refers generally to failure that would result
within the
polymeric matrix of in contrast with adhesive failure that would occur as
between the
polymeric matrix and adjoining metal layers. Thus, a high amount of cohesive
failure
is reflective of a bond strength between the polymer matrix and one or both of
the
metal layers of a sandwich composite that exceeds the internal strength of the
polymeric matrix material.
[00165] Preferably, the composite material does not delaminate (e.g.,
the
metallic layer does not delaminate from the core layer) during the processing
of the
composite material to form a part or an assembly, or during the use of the
part. As
such, the composite material preferably does not delaminate during a stamping
operation, during a joining operation (e.g., during a welding operation), or
both.
[00166] Another aspect of the invention contemplates a method for post-
consumer reclamation, recycling, or both of parts made using the present
invention.
One approach envisions providing a part having the composite structure taught
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herein, and subjecting it to a step of separating hydrocarbon compounds (e.g.,
by an
elevated temperature heating step) from the metallic materials. Either or both
of the
hydrocarbon compounds or the metallic materials can be recovered and re-used.
Another approach envisions recycling by grinding the composite material or
otherwise forming particles from the composite materials, and optionally
providing the
particles as an ingredient for the core material of a composite (such as a
composite
material described herein).
Examples
[00167] It should be appreciated that the compositions of the following
examples maybe varied by about 20% and give similar results (e.g., within
about
,20%). Further, other materials taught herein may be substituted for those
stated and
similar results are contemplated.
Example 1.
[00168] The core material for the light weight composite is prepared by melt
blending about 45 g polyamido 6 and about 72 g stainless steel fibers having
an
average diameter of about 3-10um and an average length of about 2-4 mm in a
Brabender Plastograph mixer at 260"C, with a speed of about 20 rpm. The
polyamide
6 has a density of about 1.142 g/cm3 and the steel has a density of about 7.9
9/cm3.
After mixing for about 60 minutes, the admixture is removed from the Brabender
mixer. It will be appreciated to one skilled in the art that longer or
preferably shorter
mixing times (e.g., less than about 30 minutes, less than about 20 minutes,
less than
about 10 minutes, or even less than about 5 minutes) may be used. Moreover,
such
mixing times may be employed for the other polymers of the present teaching.
Thus
prepared, example 1 contains about 18.8 volume% steel fibers and about 81.2
volume% polyamide 6 and has .a density of about 2.411 g/cm3.
Example 2.
[00169] A core material is prepared using the same method as for Example 1,
except the weight of the stainless steel fiber is about 102 g and the weight
of the
polyamide 6 is about 40g. Thus prepared, the admixture contains about 26.9
volume% steel fibers and about 73.1 volume% polyamide 6 and has a density of
about 2.962 g/cm3.
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Example 3.
[00170] A core material is prepared using the same method as for Example 1,
except the weight of the stainless steel fiber is about 35.4 g and the weight
of the
polyamide 6 is about 50.6g. Thus prepared, the admixture contains about 10
volume% steel fibers and about 90 volume% polyamide 12 and has a density of
about 1.816 g/cm'l.
Comparative Example 4.
[00171] A core material is prepared using the same method as for Example 1,
except no stainless steel fiber is used and about 53 g of the polyamide 6 is
mixed in
the Brabender Plastograph mixer. Comparative Example 5 has a density of about
1.142 g/cm3.
Comparative Examples 5-6.
[00172] Composite materials are prepared by compression molding a sandwich
panel containing two steel plates, each having a thickness of about 0.20 mm a
length
of about 74.2 mm and a width of about 124.2 mm, and Polyamide 12, without
metallic
fibers, is placed between the metal plates. The steel plates are made of No 5
temper
Aluminum killed) low carbon steel that meets AISA 1008 and ASTM A109
standards.
The thickness of the core material for comparative examples 5 and 6 is about
0.30
mm, and about 0.44 mm, respectively, as shown in Table 1. Comparative Example
5
and 6 are compression molded using a positive mold at a temperature of about
250 C and a load of about 12000 kg. The overall density of the composite
panels is
about 32-46 wl. % lower than the density of the steel used in the steel
plates. The
through-thickness electrical resistivity of comparative examples 5 and 6 is
greater
than 1x101 0-cm, indicating that these panels have insulating
characteristics.
Though stampable, attempts to weld Comparative Examples 5 and 6 to a
monolithic
steel panel results in structure that do not weld together. These samples fail
the weld
test in that the weld is weaker than the panels being welded together.
57
TABLE 1
Comparative Comparative
Example 5 Example 6
Metal Plate 1
Material Steel Steel
Thickness, mm 0.20 0.20
Metal Plate 2
Material Steel Steel
Thickness, mm 0.20 0.20
Core Material
Thickness, mm 0.30 0.44
Thickness, vol % of total 43% 57%
Metal Fiber, volume% of core 0% 0%
Polyamide 12, volume% of core 100% 100%
Total Density, g/cm2 1 5.37 4.27
Weight Saving, % 32% 46%
Core Layer Resistivity, Clem >1012 _ >1012
Weld Properties Fail Fail
Examples 7-8
[001731 Examples 7 and 8 are composite materials prepared by compression
molding a sandwich panel using the method described for Comparative Examples 7
and 8, except a core material including about 26.9 volume% of steel fibers and
about
73.1 volume% polyamide 12 is used. The steel fibers In the core material have
an
average diameter of about 3-101.tm and an average length of about .2-4 mm and
are
mixed with the polyamide 12 in a Brabenderrm Plastograph mixer at about 260 C.
The
thickness of the core material is about 0.40 mm and about 0.57 rem for
Examples 7
and 8, respectively. These samples are illustrated in Table 2. The overall
density of
the composite panels is about 29-36 wt. % lower than the density of the steel.
These
composite panels are welded .to steel sheet having a thickness of about 0.8 mm
using AC resistance welding (spot welding). Good welds (i.e., welds that are
stronger
than the panels being welded, such that a weld button is obtained when the
welded
panels are separated by force) are obtained using a welding current of about
9.7 kA
and 8 weld cycles, with a pressure of about 600 psi. These conditions are
lower than
those required for welding two monolithic sheets of 0.8 mm thick steel (12.9
KA, 15
weld cycles, 600 psi pressure). Each weld cycle is about 1/60 second and the
welding parameters include a slope of about 1 cycle (i.e., about 1/60 second),
a hold
time of about 10 cycles (i.e., about 1/6 second) and a squeeze time of about 1
second.
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TABLE 2
Example 7 Example 8 I Example 9 Example 10
Metal Plate 1
Material Steel Steel Steel Steel
Thickness, mm 0.20 0,20 0.20 0.20
Metal Plate 2
Material Steel Steel Steel Steel
Thickness, mm 0.20 0.20 0,20 0.20
Core Material
Thickness, mm 0.40 0.57 0.37 0.55
Thickness, vol 50% 59% 48% 58%
% of total
Metal Fiber, 26.9% 26.9% 20.2% 20.2%
volume% of
core
Polyamide 12, 73.1% 73.1% 79.8% 79.8%
vol % of core
Total Density, 5.61 5.04 5.43 4.70
gtcm3
Weight Saving, 29% 36% 31% 41%
=
Core Layer 910 480 740 500
Resistivity, CI=cm
Weld Properties Good Good Good Good
Examples 9-10
1001741 Examples 12 and 13 are composite materials prepared by compression
molding a sandwich panel using the method described for Comparative Examples 5-
6, except a core material including about 20.2 volume% of steel fibers and
about 79.8
volume% polyamide 12 is used. The steel fibers in the core material have an
average
diameter of about 3-101m and an average length of about 2-4 mm and are mixed '
with the polyamide 12 in a BrabenderTM Plastograph mixer at about 260 C. The
thickness of the core material is about 0.37 and about 0.55 mm, for Examples 9
and
respectively. These samples are illustrated in Table 2. The overall density of
the
composite panels is about 31-41 wt. % lower than the density of the steel.
These
composite panels are welded to steel sheet having a thickness of about 0.8 mm
using AC resistance welding (spot welding). Good welds are obtained using a
welding current of about 9.7 kA and 8 weld cycles, with a pressure of about
600 psi.
(001751 The stiffness and density of Example 9 and a monolithic sheet
of the
same steel material used in the metallic layers of Example 9, both having a
thickness
of about 0.87 mm are measured in the through-thickness direction. Example 9 is
expected to have a higher stiffness to density ratio than the monolithic sheet
of steel.
59
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Example 11
[00176] Example 11 composite material sample is prepared by compression
molding a sandwich panel using the method described for Comparative Examples
5.
except Example 3 is used for the core material. This composite panel sample is
welded to steel sheet having a thickness of about 0.8 mm using AC resistance
welding (spot welding). Good welds are obtained using a welding current of
about 9.7
kA and 8 weld cycles, with a pressure of about 600 psi.
Example 12-14
[00177] Examples 12 through 14 are neat polymers and mixtures of polymers with
stainless steel fibers prepared using the method Example 1. Examples 12
through 14
are prepared using polyamide 6 with about 0 wt%, about 3 wt. %, and about 10
wt. %
stainless steel fiber, respectively for Examples 12. 1.3, and 14. The tensile
modulus of
the core material of Example 12 is about 3.3 GPa. When the steel fiber is
added at a
concentration of about 3 wt. % (Example 13), the tensile modulus increases by
more
than 17% to about 3.9 GPa. When the steel fiber is added at a concentration of
about
wt. % (Example 14), the tensile modulus increases by more than 100% to about
7.3 GPa. The polyamide is replaced with a copolyamide and the concentration of
the
stainless steel fiber is about 0% wt. %, about 3 M. % and about 10 wt. % for
Examples 15, 16, and 17, respectively. The tensile modulus of the core
material of
Example 15 is about 700 MPa. When the steel fiber is added at a concentration
of
about 3 wt. % (Example 16), the tensile modulus increases by more than 50% to
about 1160 MPa. When the steel fiber is added at a concentration of about 10
wt. %
(Example 17). the tensile modulus increases by more than 200% to about 2280
MPa.
As such, in general this and other embodiments of the invention taught herein
may
be characterized by a tensile modulus of the filled polymeric material (e.g.,
the
material of the core layer) including metallic fibers that is greater than the
tensile
modulus of the filled polymeric material (e.g., the material of the core
layer) having
the same composition but without metallic fibers preferably by at least 15%,
more
preferably by at least 50%, even more preferably by at least about 100%, and
most
preferably by at least about 200%.
=
Examples 15-20 (Electrical Resistivity) =
[00178] Examples 15 through 20 are prepared by mixing steel fibers and a
thermoplastic in a BrabenderTM mixer, using the polymer and steel fiber
concentration
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shown in TABLE 3. The composite materials are then prepared by molding
sandwiches having 0.4 mm of the fiber filled thermoplastic layer between two
0.2 mm
thick steel sheets. The through-thickness electrical resistivity of the
composite
materials, as measured using AC Modulation, is shown in TABLE 3. All of the
composite materials filled thermoplastics have relatively low electrical
resistivity and
all of the unfilled thermoplastics have relatively high electrical
resistivity.
TABLE 3
Thermoplastic Steel Fibers (Volume %) Electrical Resistivity O=cm
Example 15 Polyam ide 0 >10"
Example 16 Polyam ide 26.9 250
Example 17 Polyam ide 10 300
= Example 18 EVA 0 >10"
Example 19 EVA 3 400
Example 20 Copolyamide 3 600
EVA= Ethylene Vinyl Acetate Copolymer
Example 21
[00179] A filled thermoplastic material is prepared by mixing about 15 volume%
low
carbon steel fibers having a diameter from about 4 to about 40 pm, and a
length from
about 1 to about 10 mm and about 85 volume % of a copolyamide of about 50 wt.
%
polyamide 6 and about 50 wt. % polyamide 6,9 (the copolymer characterized by
an
elastic modulus of about 300 MPa measured according to ISO 527-2, a melting
point
of about 130 C as measured according to ISO 11357, and an elongation at break
of
about 900 % measured according to ISO 527-3). The filled thermoplastic
material is
mixed at a temperature from about 190 C to about 250 C. The filled
thermoplastic
material is then placed between two sheets of low carbon steel, each having a
thickness of about 0.2 mm. The materials are then pressed at a temperature
from
about 200 C to about 230 C with a pressure of about 1 to about 22 MPa. The
composite material has a core thickness of the filled thermoplastic material
of about
0.4 mm. The composite material is stamped in a high speed stamping operation
with
a draw ratio greater than about 3, and no cracks or other surface defects are
observed. After stamping, the surface of the composite material is relatively
smooth
compared to the surface of a monolithic low carbon steel sample having the
same
total thickness and stamped under the same conditions. The composite material
is
then submitted to a typical e-coat process and painted with a primer and black
paint.
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The painted surface has a smooth finish with no pitting, no orange peeling.
and no
other visible surface defects. The painted surface is characterized as a class
A finish.
The surface of the painted composite material is smoother than the surface of
a
similarly processed monolithic sample of low carbon steel having a thickness
of
about 0.8 mm.
Example 22
[00180] A composite material is prepared using the same materials,
composition,
and method as Example 21, except the fibers are replaced with low carbon
fibers
having a generally rectangular cross-section in the direction transverse to
the length
of the fibers. The fibers have an average length of about 2.3 mm. The average
cross-
sectional area of the fibers is about 0.0045 mm2. The ratio of the width to
the
thickness of the fibers is about 2 to 8. The composite material has a
thickness of
about 0,8 mm. The composite material is stacked with a sample of cold rolled
steel
having a thickness of about 0.8 mm. The stack is placed in a spot welding
machine
between a pair of weld tips having a diameter of about 13 mm. A force of about
2.2
kNt is applied to the weld tips. The resistivity of the composite material in
the
through-thickness direction is determined while under force of 2.2 kNt. Thus
determined, the electrical resistivity of Example 22 composite material is
about 0.1
fl.cm or less. When welded using weld schedules typical for two sheets of cold
rolled
steel having a thickness of about 0.8 mm, the composite material welds to the
cold
rolled steel, producing a weld button having a diameter greater than the
diameter of
the weld tips. No extra heating, no extra weld cycles,, and no extra current
are
required to produce a good weld with Example 22.
Example 22B
[00181] Example 22B is identical as Example 22, except the concentration of
the
metallic fiber in the filled polymeric material is increased to about 20
volume percent
and the concentration of the polymer is reduced to about 80 volume percent.
The
composite material of Example 228 is welded to a sheet of galvannealed steel
having a thickness of about 0.8 mm. An electrode having a face diameter of
about
3.8 mm is used on the side of the weld stack having the composite material and
an
electrode having a face diameter of about 4.8 mm is used on the side having
the
galvannealeci steel. A force of about 610 lbs is applied to the weld stack by
the -
electrodes. The materials are welded using mid frequency DC welding, having a
frequency of about 1,000 Hertz. Each weld is done on samples having 4a width
of
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about 25 mm and a length of about 75 mm. The weld time is constant at about
200
miliseconds..Welds are made using weld currents ranging from about 8.8 ka to
over
13 kA. The size of the weld button on the composite sheet is measured after
the
welding is completed. The weld button size and the weld current of each weld
sample
46 is shown in a graph 30 in FIG. 6. At low weld currents given by the region
44, the
weld button size is less than the 95% of the diameter of the electrode 36 that
is used
on the face of the composite material during the welding step. At intermediate
weld
currents illustrated by the region 40, the button size is greater than 95% of
the
diameter of the electrode ,36. At high weld currents illustrated by region 42,
the there
is expulsion of metal and/or a loud popping noise during the welding and the
resulting
welds are unacceptable. The minimum weld current 34 for obtaining acceptable
welds is about 10 kA for Example 22B. The maximum weld current 32 for
obtaining
acceptable welds is about 13 kA. The difference between the maximum weld
current
32 and the minimum weld current 34 is the current range 38. Thus measured, the
weld current range of Example 226 is about 3.0 kA. For comparison, the weld
current
range is for a weld stack consisting of two monolithic sheets of the
galvannealed
steel each having a thickness of about 0.8 mm similarly measured and is
determined
to be less than about 1.3 kA. Surprisingly, the composite material of Example
22B is
easier to weld (i.e., has a broader processing window for welding) than the
galvannealed steel, as determined by its higher weld current range.
Example 22C
[001821 The weld current range is measured for a weld stack consisting of
two
monolithic sheets of the galvannealed steel each having a thickness of about
0.8 mm
similarly measured and is determined to be less than about 1.3 kA. The weld
current
range is measured using the same method as for Example 228. Surprisingly, the
composite material of Example 228 is easier to weld (i.B., has a broader
processing
window for welding) than the galvannealed steel, as determined by its higher
weld
current range (e.g. , compared to Example 22C).
Example 22D
[00183) Example 22D is a composite material having the same composition,
filled thermoplastic polymer, and structure as Example 228. The weld current
range
of Example 220 is measured using the same conditions as In Example 228, except
the load on the weld tips is about 2.76 kN (about 600 lb), the upslope time is
about
50 ms,the weld time is about 300 ms, and the initial weld current is about 8-9
kA. The
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weld current range is first measured for a weld stock consisting of the
Example 220
composite material and a sheet of uncoated deep drawing quality steel (Le.,
000)
having a thickness of about 1.2 mm. The weld button size is measured at
different
weld currents as shown in FIG. 7. Good welds characterized by i) a button size
of
about 3.6 mm or more in diameter and ii) no metal expulsion are obtained when
the
weld current is from about 6.4 kA to about 9.2 kA. The weld current range is
determined to be about 2.8 kA for welding the Example 220 to 1.2 mm thick
uncoated DDO.
[00184] Next, weld stacks consisting of the composite material and 0.8
mm
thick galvannealed steel are prepared and welded using the same conditions as
for
the uncoated DOC steel. Surprisingly, good welds are obtained without changing
the
upslope time, the weld time, the initial weld current, or the load on the weld
tips. The
weld button is measured at different weld currents as shown in FIG. 8. Good
welds
characterized by I) a button size of about 3.6 mm or more in diameter and ii)
no metal
expulsion are obtained when the weld current is from about 7.75 kA to about
9.45 kA.
The weld current range is determined to be about 1.7 kA for welding the
Example
220 composite material to 0.8 mm thick galvannealed steel.
[00185] The composite material of Example 22D is also welded to hot dip
galvanized steel (Le., HOG) having a thickness of about 1.5 mm. Weld stacks
consisting of the composite material and the 1.5 mm thick HOG are prepared and
welded using the same conditions as for the uncoated DO steel. Surprisingly,
good
welds are obtained without changing the upslope time, the weld time, the
initial weld
current, or the load on the weld tips. The weld button is measured at
different weld
currents as shown in FIG. 9. Good welds characterized by i) a button size of
about
3.6 mm or more in diameter and ii) no metal expulsion are obtained when the
weld
current is from about 7.35 kA to about 9.35 kA. The weld current range is
determined
to be about 2.0 kA for welding the Example 220 composite material to 1.5 mm
thick
HOG.
[00186] Surprisingly, the same welding conditions can be used for
welding the
composite material to different types of steel (e.g., 000. HOG, or
galvannealed steel).
Additionally, it is surprising that the composite material is capable of being
welded to
steel having thickness varying by.about 87% (Le. , from 0.8 mm to 0.8 mm x
187% =
1.5 mm) without changing the welding conditions. It is also surprising that
for the
different types of steels, and the different thickness of the steel, the
welding to the
composite material is characterized by generally large weld current ranges.
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Example 23
[001871 A composite material is prepared using the same materials,
composition,
and method as Example 21, except the metal sheets are replaced by 0.2 mm thick
sheets of a high strength steel having a yield strength of about 350 MPa, a
tensile
strength of about 460 MPa, and an elongation of about 22%. The composite
material
is expected to have a yield strength of about 193 MPa, a tensile strength of
about
253 MPa, and an elongation of about 22%. The density of the composite material
is
expected to be about 34 % less than a monolithic sheet of the low carbon steel
having the same thickness (about 0.8 mm). The composite material is expected
to
have a yield strength that is about 50 MPa or more higher than the yield
strength of
the monolithic sheet of low carbon steel having the same thickness. The
composite
material is expected to have a tensile strength that is at least about 90% of
the
tensile strength of the monolithic sheet of low carbon steel having the same
thickness. The composite material is expected to have a flexural modulus that
is at
least about 85% of the flexural modulus of the monolithic sheet of low carbon
steel
having the same thickness.
[00188] As used herein, unless otherwise stated, the teachings envision that
any
member of a genus (list) may be excluded from the genus; and/or any member of
a
Markush grouping may be excluded from the grouping.
[00189] Unless otherwise stated, any numerical values recited herein include
all
Values from the lower value to the upper value in increments of one unit
provided that
there is a separation of at least 2 units between any lower value and any
higher
value. As an example, if it is stated that the amount of a component, a
property, or a
value of a process variable such as, for example, temperature, pressure, time
and
the like is, for example, from 1 to 90, preferably from 20 to 80, more
preferably from
30 to 70, it is intended that intermediate range values such as (for example,
15 to 85,
22 to 68, 43 to 51, 30 to 32 etc.) are within the teachings of this
specification.
Likewise, individual intermediate values are also within the present
teachings. For
values which are less than one, one unit is considered to be 0.0001, 0.001,
0.01 or
0.1 as appropriate. These are only examples of what is specifically intended
and all
possible combinations of numerical values between the lowest value and the
highest
value enumerated are to be considered to be expressly stated in this
application in a
= similar manner. As can be seen, the leaching of amounts expressed as
"parts by
weight" herein also contemplates the same ranges expressed in terms of percent
by
weight. Thus, an expression in the Detailed Description of the Invention of a
range in
terms of at -x' parts by weight of the resulting polymeric blend composition"
also
contemplates a teaching of ranges of same recited amount of "x" in percent by
weight
- of the resulting polymeric blend composition."
[00190] Unless otherwise stated. all ranges include both endpoints and all
numbers
between the endpoints. The use of "about" or "approximately" in connection
with a
range applies to both ends of the range. Thus, "about 20 to 30" is intended to
cover
"about 20 to about 30", inclusive of at least the specified endpoints.
[00191] The term "consisting essentially of' to describe a combination shall
include the
elements, ingredients, components or steps identified, and such other elements
ingredients, components or steps that do not materially affect the basic and
novel
characteristics of the combination. The use of the terms "comprising" or
"including" to
describe combinations of elements, ingredients, components or steps herein
also
contemplates embodiments that consist or even consist essentially of the
elements,
ingredients, components or steps.
[00192] Plural elements, ingredients, components or steps can be provided by a
single
integrated element, ingredient, component or step. Alternatively, a single
integrated
element, ingredient, component or step might be divided into separate plural
elements,
ingredients, components or steps. The disclosure of "a" or "one" to describe
an element,
ingredient, component or step is not intended to foreclose additional
elements,
ingredients, components or steps. All references herein to elements or metals
belonging
to a certain Group refer to the Periodic Table of the Elements published and
copyrighted
by CRC Press, Inc., 1989. Any reference to the Group or Groups shall be to the
Group
or Groups as reflected in this Periodic Table of the Elements using the IUPAC
system
for numbering groups.
[00193] As used herein the terms "polymer" and "polymerization" are generic,
and can
include either or both of the more specific cases of "homo-" and copolymer"
and
"homo- and copolymerization", respectively.
[00194] It is understood that the above description is intended to be
illustrative and not
restrictive. Many embodiments as well as many applications besides the
examples
provided will be apparent to those of skill in the art upon reading the above
description
and the claims as originally filed.
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CA 2842609 2019-10-18
[00 195] The
omission in the following claims of any aspect of subject matter that
is disclosed herein is not a disclaimer of such subject matter. nor should it
be regarded
that the inventors did not consider such subject matter to be part of the
disclosed
inventive subject matter.
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CA 2842609 2019-10-18
