Note: Descriptions are shown in the official language in which they were submitted.
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IMPROVED FIBERGLASS REINFORCED COMPOSITES
[0001] The present application claims priority to U.S. provisional application
nos.
61/679,196, filed on August 3, 2012 and 61/727,453, filed on November 16,
2012, which are
hereby incorporated by reference in their entireties.
BACKGROUND
[0002] Conventional asphalt roofing shingles are made by applying an asphalt
coating to a
fiberglass web, embedding sand or other roofing granules in the asphalt
coating while still
soft, and then subdividing the web so formed into individual shingles once the
asphalt has
hardened. The fiberglass web is normally made from glass fibers bound together
by a suitable
resinous binder. In addition, a finely ground inorganic particulate filler is
normally included
in the asphalt coating to reduce cost, improve the heat distortion resistance
of the shingle, and
reduce asphalt UV degradation.
[0003] Commonly assigned U.S. Patent No. 7,951,240, the entire disclosure of
which is
incorporated herein by reference, indicates that the tear strength of roofing
shingles made in
this way can be affected by the type of particulate filler contained in the
asphalt coating. In
particular, this patent indicates that the tear strength of such roofing
shingles may be
compromised if hard fillers such as dolomite, silica, slate dust, high
magnesium carbonate
and the like are used.
[0004] It has been found that the physical properties of many types of
fiberglass reinforced
polymer composites may be improved by including core-shell rubber
nanoparticles in a
resinous binder that is applied to glass fibers before they are combined with
the polymer
foiming the matrix or body of a composite, such as a fiberglass mat for use in
making
shingles.
[0005] Moreover, it has also been found that glass fibers carrying these core-
shell rubber
nanoparticles can be easily made by including them in the size that is applied
to the fibers as
they are made rather than including them is a separate polymer binder
subsequently applied
to the fibers in a later manufacturing process, in which the previously-sized
glass fibers are
used to make useful products.
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SUMMARY
[0006] In some exemplary embodiments of the present invention, it has been
found that the
physical properties of a fiberglass reinforced composite may be improved by
incorporating
core-shell rubber nanoparticles within the resinous binder of the composite.
[0007] In various exemplary embodiments of the present invention, the
fiberglass reinforced
composite comprises an improved roofing mat for use in making asphalt roofing
shingles.
Some exemplary aspects of the improved roofing mat comprise a fiberglass mat
composed of
multiple glass fibers and a resinous binder holding the individual glass
fibers together,
wherein the resinous binder includes rubber core-shell nanoparticles.
[0008] Moreover, in accordance with further exemplary aspects of this
invention, it has been
found that glass fibers carrying these core-shell rubber nanoparticles may be
made by
including core-shell rubber nanoparticles in the size that is applied to the
fibers as they are
made rather than, or in addition to, including the nanoparticles in a separate
polymer binder
subsequently applied to the fibers in a later manufacturing process.
[0009] Thus, exemplary aspects of this invention provide a fiberglass
reinforced polymer
composite is provided comprising a matrix polymer and glass fibers dispersed
in the matrix
polymer, wherein the surfaces of the glass fibers carry a coating of core-
shell rubber
nanoparticles.
[00010] In accordance with other exemplary aspects of the present invention,
glass filaments
and fiber for use in making a fiberglass reinforced polymer composite is
provided. The glass
filaments and fibers comprise a glass filament or fiber substrate carrying a
coating of an
aqueous size composition, the aqueous size composition comprising a film-
forming polymer,
an organosilane coupling agent and core-shell rubber nanoparticles.
[00011] Further exemplary aspects of the present invention also provide a
continuous
process for making glass fibers comprising charging molten glass through
multiple orifices in
a bushing to produce molten streams of glass, allowing the molten streams of
glass to solidify
to foini individual filaments. The individual filaments may be coated with an
incipient size
composition containing a lubricant, a film forming resin and an organosilane
coupling agent,
and combined together to form the fiber. The process may further comprise
applying a
coating of core-shell rubber nanoparticles to the fiber.
[00012] Some exemplary embodiments provide fiberglass reinforced polymer
composite
comprising a plurality of individual glass fibers fiberglass and a resinous
binder, wherein
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core-shell rubber nanoparticles are incorporated within the resinous binder of
the composite,
The individual glass fibers may form a fiberglass mat held together by the
resinous binder.
The resinous binder may include 0.1 to 20 wt.% rubber core-shell
nanoparticles, or 0.5 to 10
wt.% wt.% rubber core-shell nanoparticles, based on the total amount of resin
in the binder.
The average particle size of the rubber core-shell nanoparticles may be 250 nm
or less. The
resinous binder may be formed from a urea formaldehyde resin, an acrylic resin
or a mixture
thereof.
[00013] In some exemplary embodiments, the core of the rubber core-shell
nanoparticles is
made from a synthetic polymer rubber selected from the group consisting of
styrene/butadiene, polybutadiene, silicone rubber (siloxanes), acrylic rubbers
and mixtures
thereof.
[00014] In other exemplary embodiments, the composite is an asphalt roofing
shingle.
[00015] In various exemplary embodiments, an improved roofing mat for use in
making
asphalt roofing shingles is provided. The improved roofing mat may comprise a
fiberglass
mat composed of multiple glass fibers and a resinous binder holding the
individual glass
fibers together. The resinous binder may include rubber core-shell
nanoparticles. The
resinous binder may include 0.1 to 20 wt.% rubber core-shell nanoparticles,
based on the total
amount of resin in the binder. The average particle size of the rubber core-
shell nanoparticles
may be 250 nm or less. The resinous binder may be formed from a urea
formaldehyde resin,
an acrylic resin or a mixture thereof. The core of the rubber core-shell
nanoparticles may be
made from a synthetic polymer rubber selected from the group consisting of
styrene/butadiene, polybutadiene, silicone rubber (siloxanes), acrylic rubbers
and mixtures
thereof.
[00016] In yet other exemplary embodiments, an improved asphalt roofing
shingle is
provided comprising a fiberglass roofing mat composed of multiple glass fibers
and a
resinous binder holding the individual glass fibers together and an asphalt
coating covering
the fiberglass roofing mat. The asphalt coating may include an inorganic
particulate filler.
The asphalt coating may further contain roofing granules embedded therein. In
some
exemplary embodiments, the resinous binder of the fiberglass roofing mat
includes rubber
core-shell nanoparticles. The resinous binder may include 0.1 to 20 wt.%
rubber core-shell
nanoparticles, or from 0.5 to 10 wt.% rubber core-shell nanoparticles, based
on the total
amount of resin in the binder, The average particle size of the rubber core-
shell nanoparticles
may be 250 nm or less. The resinous binder may be formed from a urea
formaldehyde resin,
an acrylic resin or a mixture thereof. The core of the rubber core-shell
nanoparticles may be
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made from a synthetic polymer rubber selected from the group consisting of
styrene/butadiene, polybutadiene, silicone rubber (siloxanes), acrylic rubbers
and mixtures
thereof. The asphalt coating may include 30 to 80 wt.%, based on the entire
weight of the
filled asphalt, of an inorganic particular filler selected from the group
consisting of dolomite,
silica, slate dust and high magnesium carbonate.
[00017] In various exemplary embodiments, a fiberglass reinforced polymer
composite is
provided comprising a matrix polymer and glass fibers dispersed in the matrix
polymer. The
surfaces of the glass fibers may carry a coating of core-shell rubber
nanoparticles. In other
exemplary embodiments, the surfaces of the glass fibers carry a coating
comprising a mixture
of core-shell rubber nanoparticles and a film-forming polymer. In other
exemplary
embodiments, the surfaces of the glass fibers carry a first coating of an
incipient size
composition applied to the fibers during fiber manufacture, the incipient size
composition
comprising core-shell rubber nanoparticles, a film-forming polymer and an
organosilane
coupling agent. The incipient size composition may contain a hydrocarbon wax.
[00018] In some exemplary embodiments, the glass fibers are made by combining
multiple
attenuated glass filaments together to form individual fibers and the
incipient size
composition is applied to the individual glass filaments before they are
combined.
[00019] In some exemplary embodiments, a second coating of a secondary
incipient size
composition applied to the fibers during fiber manufacture after the
individual glass filaments
are combined, the secondary incipient size composition comprising additional
core-shell
rubber nanoparticles and a film-fointing polymer.
[00020] The glass fibers may be made by combining multiple attenuated glass
filaments
together to form individual fibers, wherein the surfaces of the glass fibers
carry a first coating
of an incipient size composition applied to the individual glass filaments
before they are
combined, the incipient size composition comprising a film-forming polymer and
an
organosilane coupling agent, and further wherein the surfaces of the glass
fibers carry a
second coating of a secondary incipient size composition applied to the fibers
during fiber
manufacture after the individual glass filaments are combined, the secondary
incipient size
composition comprising core-shell rubber nanoparticles and a film-forming
polymer.
[00021] The average particle size of the core-shell rubber nanoparticles may
be 250 run or
less. The core of the rubber core-shell nanoparticles may be made from a
synthetic polymer
rubber selected from the group consisting of styrene/butadiene, polybutadiene,
silicone
rubber (siloxanes), acrylic rubbers and mixtures thereof.
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[00022] In some exemplary embodiments, the core-shell rubber nanoparticles are
applied to
the reinforcing glass fibers in the form of a mixture of the core-shell rubber
nanoparticles and
a film forming resin, and further wherein the mixture includes 0.1 to 20 wt.%
rubber core-
shell nanoparticles, 0.5 to 10 wt.% wt.% rubber core-shell nanoparticles,
based on the total
amount of film forming resin in the mixture.
[00023] In some exemplary embodiments, the fiberglass reinforced polymer
composite is
roofing shingle.
[00024] In some exemplary embodiments, a glass filament for use in making a
fiberglass
reinforced polymer composite is provided. The glass filament may include a
glass filament
substrate carrying a coating of an incipient size composition, the incipient
size composition
comprising a film-forming polymer, an organosilane coupling agent and core-
shell rubber
nanoparticles.
[00025] In other exemplary embodiments, a glass fiber for use in making a
fiberglass
reinforced polymer composite is provided. The glass fiber may comprise a glass
fiber
substrate carrying a coating comprising a film forming polymer and core-shell
rubber
nanoparticles.
[00026] The glass fiber may be composed of multiple glass filaments combined
together, the
surfaces of the glass filaments carrying a first coating of an incipient size
composition applied
to the filaments before being combined, the incipient size composition
comprising a film-
forming polymer, an organosilane coupling agent and core-shell rubber
nanoparticles.
[00027] The surfaces of the glass fiber carry a second coating of a secondary
incipient size
composition applied to the fiber after the filaments forming the fiber are
combined, the
secondary incipient size composition comprising additional core-shell rubber
nanoparticles
and a film-forming polymer.
[00028] In other exemplary embodiments, a glass fiber is made by combining
multiple
attenuated glass filaments together to form the fiber, wherein the surfaces of
the glass fiber
carry a first coating of an incipient size composition applied to the
individual glass filaments
before they are combined, the incipient size composition comprising a film-foi
tiling polymer
and an organosilane coupling agent. The surfaces of the glass fiber may
additionally carry a
second coating of a secondary incipient size composition that is applied to
the fiber after the
individual glass filaments are combined, the secondary incipient size
composition comprising
a film-forming polymer and core-shell rubber nanoparticles.
[00029] The average particle size of the core-shell rubber nanoparticles may
be 250 nm or
less. Additionally, the core of the rubber core-shell nanoparticles may be
made from a
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synthetic polymer rubber selected from the group consisting of
styrene/butadiene,
polybutadiene, silicone rubber (siloxanes), acrylic rubbers and mixtures
thereof.
[00030] The core-shell rubber nanoparticles may be applied to the glass
filaments or fiber in
the form of a mixture of the core-shell rubber nanoparticles and a film
forming resin, and
further wherein the mixture includes 0.1 to 20 wt.% core-shell rubber
nanoparticles, based on
the total amount of film forming resin in the mixture.
[00031] In yet further exemplary embodiments, a continuous process for making
glass fiber
is provided that includes charging molten glass through multiple orifices in a
bushing to
produce molten streams of glass, allowing the molten streams of glass to
solidify to form
individual filaments, coating the individual filaments with an incipient size
composition
containing a lubricant, a film forming resin and an organosilane coupling
agent, and
combining the individual filaments together to form the fiber. The process may
further
comprises applying a coating of core-shell rubber nanoparticles to the fiber.
[00032] The core-shell rubber particles may be applied to the glass fiber by
including the
core-shell rubber particles in the incipient size composition.
[00033] In some exemplary embodiments, the core-shell rubber particles are
applied to the
glass fiber by coating the glass fiber after it is formed with a secondary
incipient size
composition comprising core-shell rubber nanoparticles and a film-forming
polymer. The
incipient size may also contains core-shell rubber nanoparticles.
[00034] The average particle size of the core-shell rubber nanoparticles may
be 250 nm or
less and the core of the rubber core-shell nanoparticles may be made from a
synthetic
polymer rubber selected from the group consisting of styrene/butadiene,
polybutadiene,
silicone rubber (siloxanes), acrylic rubbers and mixtures thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[00035] This invention may be better understood by reference to the following
drawings
wherein:
[00036] Fig. 1 is a box plot of data illustrating the tensile strengths of two
certain fiberglass
mats;
[00037] Fig. 2 is a box plot of data illustrating the tear strengths of two
certain fiberglass
mats;
[00038] Fig. 3 is a box plot of data illustrating the tensile strengths of two
certain asphalt
roofing shingles;
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[00039] Fig. 4 is a bar chart showing the effect the core-shell rubber
nanoparticles of this
invention have on the burst strengths of glass fiber wound high pressure
composite pipes
made in accordance with this invention;
[00040] Fig. 5 is a graph showing the effect these core-shell rubber
nanoparticles have on
the interlaminar shear strength of the glass fiber wound high pressure
composite pipes of Fig.
1; and
[00041] Fig. 6 is a graph showing the effect these core-shell rubber
nanoparticles have on
the tension exerted on the glass fibers used to form the glass fiber wound
high pressure
composite pipes of Fig. 4 during their manufacture.
DETAILED DESCRIPTION
Rubber Core-Shell Particles
[00042] Rubber core-shell particles are known articles of commerce described
in several
patents. For example, they are described in EP 2 053 083 Al, EP 5 830 086 B2,
U.S.
5,002,982, U.S. 2005/0214534, JP 11207848, U.S. 4,666,777, U.S. 7,919,549 and
U.S.
2010/0273382, the disclosures of each being incorporated herein by reference
in their
entireties. Generally speaking, they are composed of nanoparticles having a
thelluoplastic or
thermosetting polymer shell and a core made from a synthetic polymer rubber
such as
styrene/butadiene, polybutadiene, silicone rubber (siloxanes) or acrylic
rubbers. Generally,
they have average particle sizes of about 250 urn or less, more commonly about
200 nm or
less, about 150 nrn or less or even about 100 nm or less and a fairly narrow
particles size
distribution. They are commercially available from a number different sources
including
Kenaka Corporation of Pasadena, Texas.
Fiberglass Manufacture
[00043] Glass fibers are typically made by a continuous manufacturing process
in which
molten glass is forced through the holes of a "bushing," the streams of molten
glass thereby
formed are solidified into filaments, and the filaments are combined together
to form a fiber
or "roving" or "strand." Glass fiber manufacturing processes of this type are
known and
described in numerous patents. Examples include U.S. 3,951,631, U.S.
4,015,559, U.S.
4,309,202, U.S. 4,222,344, U.S. 4,448,911, U.S. 5,954,853, U.S. 5,840,370 and
U.S.
5,955,518, the disclosures of each being incorporated herein by reference in
their entireties.
The rate at which glass fibers are typically produced by such processes is on
the order of
4,000 to 15,000 feet per minute (about 1,220 to 4,572 meters per minute). It
will therefore be
appreciated that the time over which such glass manufacturing processes occur,
that is to say
the period between the time when the molten glass leaves the bushing and the
time when the
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filly sized and formed glass fibers or strands are packaged, stored and/or
used is very short,
on the order of a fraction of a second.
[00044] The glass fibers can be made from any type of glass. Examples include
A-type
glass fibers, C-type glass fibers, E-type glass fibers, S-type glass fibers,
ECR-type glass
fibers (e.g., Advantex glass fibers commercially available from Owens
Corning), Hiper-
texTAI, wool glass fibers, and combinations thereof. In addition, synthetic
resin fibers such as
those made from polyester, polyamide, aramid, and mixtures thereof can be also
be included
in the fiberglass mats of this invention. Similarly, fibers made from one or
more naturally
occurring materials such cotton, jute, bamboo, ramie, bagasse, hemp, coir,
linen, kenaf, sisal,
flax, henequen, and combinations thereof can also be included, as can carbon
fibers.
[00045] Normally, an aqueous coating or "size" is applied to glass filaments
after they have
solidified but before they are contacted with the rotating spindle for
attenuation. Such sizes
typically contain a lubricant to protect the fibers from damage by abrasion, a
film-forming
resin to help bond the fibers to the polymer folining the body or matrix of
the composite in
which the fibers will be used, and an organosilane coupling agent to improve
the adhesion of
the film-forming resin and matrix polymer to the surfaces of the glass fibers.
Although such
sizes can be applied by spraying, they are typically applied by passing the
filaments over a
pad or roller containing the size on its surfaces.
[00046] Sized glass fibers made in this way are used in the manufacture of a
variety of
different fiberglass reinforced polymer composites. In the majority of these
manufacturing
processes, the sized glass fibers are combined with the matrix polymer
fainting the body or
matrix of the composite before the glass fibers are arranged in final foini in
the product to be
made. In another approach, the sized glass fibers are first assembled into a
"perform, which
is then impregnated with the matrix resin forming the body of the composite.
This is the
approach used in the manufacture of roofing shingles, in which the glass
fibers are formed
into a self-supporting web (perform) and the web so made coated with asphalt,
which then
solidifies to form the final asphalt shingle product.
[00047] The fiberglass performs used in this approach are normally self-
supporting or at
least coherent in the sense that the individual sized glass fibers will not
separate from one
another when exposed to the stresses and forces occurring when the prefoint is
manipulated
and/or impregnated with the matrix resin. For this purpose, the sized glass
fibers are
normally coated with an additional film forming resin to bond the fibers
together. For
convenience, coating compositions used for this purpose are referred to in
this document as
"binder sizes." These binder sizes will be understood to be different from
the size
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compositions applied to the glass filaments and fibers as part of their
manufacturing process,
which are referred to in this document as "incipient sizes" or "incipient size
compositions."
[00048] From the above, it should be clear that processes for making glass
fibers and
processes for using glass fibers are regarded in industry as separate and
distinct from one
another. For this reason, process steps or operations which occur during
manufacture of glass
fibers are typically referred to as "in-line" steps or operations. In
contrast, process steps or
operations which occur during the use of previously-made glass fibers, such as
in the
manufacture of fiberglass reinforced polymer composites, are typically
referred to as "off-
line" steps or operations. This terminology is used, for example, in the above-
mentioned
U.S. 5,840,370, as well as U.S. 8,163,664, U.S. 7,279,059, U.S. 7,169,463,
U.S. 6,896,963
and especially U.S. 6,846,855. The disclosures of each of these patents being
incorporated
herein by reference in their entireties. This terminology is also used in this
disclosure.
Fiberglass Reinforced Polymer Composites
[00049] Various aspects of this invention also relate to making any type
fiberglass
reinforced polymer composite. Such products are well known in industry, and
are often
referred to as "fiberglass reinforced plastics." They are composed of glass
reinforcing fibers
and a polymer resin forming the body or "matrix" of the composite. For
convenience, these
polymers are sometimes referred to in this document as "matrix polymers."
Also, in the
context of this case, "polymer resin" and "polymer" are used in their broadest
sense as
including both manmade synthetic resins as well as naturally occurring
resinous materials
such as asphalt and the like.
[00050] The fiberglass reinforced polymer composites of this invention can be
made from
any type of glass fiber. Examples include A-type glass fibers, C-type glass
fibers, E-type
glass fibers, S-type glass fibers, ECR-type glass fibers (e.g., Advantex(11)
glass fibers
commercially available from Owens Corning), Hiper-texTM, and combinations
thereof.
[00051] The inventive fiberglass reinforced polymer composites can also
include fibers
made from materials other than glass, examples of which include synthetic
resin fibers such
as those made from polyester, polyamide, aramid, and mixtures thereof.
Similarly, fibers
made from one or more naturally occurring materials such cotton, jute, bamboo,
ramie,
bagasse, hemp, coir, linen, kenaf, sisal, flax, henequen, and combinations
thereof can also be
included, as can carbon fibers. Similarly, inventive fiberglass reinforced
polymer composites
can also include non-fibrous fillers, examples of which include calcium
carbonate, silica sand
and wollastonite.. Preferably, the fiberglass reinforced polymer composites of
this invention
contain a combined total of no more than about 5 wt.% of non-glass fibers and
fillers, based
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on the weight of all the fibers and fillers in the composite. More preferably,
all or essentially
all of the fibers in the fiberglass composites of this invention are glass
fibers.
[00052] Similarly, the fiberglass reinforced polymer composites of this
invention can be
made from any resinous binder which has previously been used or may be used in
the future
as the matrix polymer for making the body or matrix of fiberglass reinforced
plastic
composites.
Examples include polyolefins, polyesters, polyamides, polyacrylamides,
polyimides, polyethers, polyvinylethers, polystyrenes, polyoxides,
polycarbonates,
polysiloxanes, polysulfones, polyanhydrides, polyimines, epoxies, acrylics,
polyvinylesters,
polyurethane, maleic resins, urea resins, melamine resins, phenol resins,
furan resins,
polymer blends, alloys and mixtures thereof. Epoxy resins are especially
preferred.
[00053] The amount of resinous binder that should be included in the
fiberglass reinforced
polymer composites of this invention can vary widely and any conventional
amount can be
used. In
some exemplary embodiments, in the case of fiberglass mats, the amount of
resinous binder will be about 10 to 30 wt.%, more typically about 14 to 25
wt.% or even
about 16 to 22 wt.%, based on the weight of the fiberglass mat as a whole.
[00054] Fiberglass reinforced polymer composites can be made by a variety of
different
manufacturing techniques including simple coating and laminating processes,
but are most
commonly made by molding. Two different types of molding processes are
commonly used,
wet molding processes and composite molding processes. In wet molding
processes, the
glass reinforcing fibers and the matrix polymer are combined in the mold
immediately prior
to molding. For instance, fiberglass mats produced in accordance with this
invention may be
made by a wet laid molding process in which wet chopped glass fibers, after
being deposited
onto a moving screen from an aqueous slurry, are coated with an aqueous
dispersion of a
resin binder which is then dried and cured. The formed non-woven web is an
assembly of
randomly dispersed, individual glass filaments bound together at their
interstices by the
resinous binder.
[00055] As stated above, the fiberglass mats of this invention include a
resinous binder for
holding the fibers together. For this purpose, any resinous binder which has
previously been
used or may be used in the future for making fiberglass mats used in the
manufacture of
asphalt roofing shingles can be used as the resinous binder of this invention.
Examples
include urea formaldehyde resins, acrylic resins, polyurethane resins, epoxy
resins, polyester
resins and so forth. Urea formaldehyde resins and acrylic resins are
preferred, while mixtures
of urea folinaldehyde resins and acrylic resins are even more preferred. In
such mixtures, the
amount of acrylic resin is desirably about 2 to 30 wt.%, more desirably about
5 to 25 wt.% or
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even about 10 to 20 wt.% of the combined amounts of urea formaldehyde resin
and acrylic
resin in the binder, on a dry solids basis.
[00056] The amount of resinous binder that should be included in the
fiberglass mats of this
invention can vary widely and any conventional amount can be used. Natmally,
the amount
of resinous binder will be about 10 to 30 wt.%, more typically about 14 to 25
wt.% or even
about 16 to 22 wt.%, based on the weight of the fiberglass mat as a whole.
[00057] The physical structure of the fiberglass mat of this invention is not
critical and any
physical structure which has previously been used, or may be used in the
future for making
fiberglass mats for asphalt roofing shingles, can be used for making the
fiberglass mat of this
invention. For example, nonwoven webs of glass fibers as well as woven and
nonwoven
fiberglass fabrics or scrim can be used for making the fiberglass mats of this
invention.
[00058] Most commonly, however, the fiberglass mat of this invention will be
made by a
wet laid process in which wet chopped glass fibers, after being deposited onto
a moving
screen from an aqueous slurry, are coated with an aqueous dispersion of a
resin binder which
is then dried and cured. The formed non-woven web is an assembly of randomly
dispersed,
individual glass filaments bound together at their interstices by the resinous
binder.
Roofing Shingle
[00059] In some exemplary embodiments, an inventive asphalt roofing shingle is
made from
the inventive fiberglass web, as described above, using conventional
production methods, i.e.,
by applying a molten asphalt coating composition to the inventive fiberglass
web, embedding
sand or other roofing granules in this asphalt coating while still soft, and
then subdividing the
web so formed into individual roofing shingles once the coating asphalt has
hardened. Any
production method may be used that has been used, or used in the future, may
be suitable in
producing the inventive fiberglass mat and shingles. Any fiberglass mat that
has previously
been used, or may be used in the future, for making asphalt roofing shingles
can be suitable
for use in making the inventive fiberglass mats and shingles.
[00060] For this purpose, any asphalt coating composition which has previously
been used
or may be used in the future for making asphalt roofing shingles may be
suitable for use as
the asphalt coating in this invention. As described in the above-noted U.S.
7,951,240, such
asphalt coating compositions include a substantial amount of inorganic
particulate filler. In
addition, they can be made from a variety of different types and grades of
asphalt and can
also include various different optional ingredients such as polymeric
modifiers, waxes and
the like. Any of the different grades of asphalt described there, as well as
any of the different
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inorganic particulate fillers and optional ingredients described there, may be
suitable for
making the roofing shingles of this invention.
[00061] In addition to these ingredients, the asphalt coating composition used
in this
invention also includes an inorganic particulate filler. For this purpose, any
inorganic
particulate filler which is or becomes known for use in making asphalt roofing
shingles can
be used. For example, calcite (crushed limestone), dolomite, silica, slate
dust, high
magnesium carbonate, rock dust other than crushed limestone, and the like can
be used.
Concentrations on the order of 30 to 80 wt.%, based on the entire weight of
the asphalt
coating, can be used although concentrations of about 40 to 70 wt.% or even of
about 50 to
70 wt.% are more typical.
[00062] As indicated above, some of these inorganic particulate fillers are
known to
adversely affect the tear strength of asphalt roofing shingles made with these
materials. In
particular, inorganic fillers which exhibit a high degree of hardness (i.e., a
hardness greater
than about 3 Moh) such as dolomite, silica, slate dust, high magnesium
carbonate, etc., are
known to produce asphalt shingles having lower tear strengths than otherwise
identical
shingles made from softer inorganic filler such as calcite (crushed limestone)
and the like.
Therefore, it is common practice in this industry to use calcite or other soft
inorganic
particulate as the asphalt filler, as least when asphalt shingles of superior
tear strengths are
desired. Tear strength is an important property because it reflects the
ability of an installed
shingle to resist being destroyed or otherwise torn off a roof substrate by a
strong wind. The
same cannot be said for tensile strength, as tear strength and tensile
strength do not normally
correlate with one another, at least in asphalt roofing shingles and the
fiberglass mats from
which they are made. Indeed, tear strength and tensile strength can even be
inversely
proportional in some of these products.
Core-Shell Fiberglass Mats
[00063] In accordance with various aspects of this invention, it has been
found that the poor
tear strength problem of traditional asphalt roofing shingles can be overcome
or otherwise
obviated by incorporating core-shell rubber particles into the resin binder
used to make the
fiberglass mat from which the inventive asphalt roofing shingle is made.
Therefore, in
accordance with various aspects of this invention, asphalt roofing shingles
exhibiting superior
tear strengths can be produced even though hard inorganic fillers such as
dolomite, silica,
slate dust, high magnesium carbonate, and the like are included in their
asphalt coating
compositions.
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[00064] Once the asphalt coating composition of this invention is applied to
the inventive
fiberglass mat, a conventional roofing granule such as sand or the like is
applied to and
embedded in this asphalt coating while still soft, such as in a conventional
manner. The
asphalt coating is then allowed to harden, and the hardened web so formed is
then subdivided
into individual roofing shingles.
[00065] It has already been proposed to use latexes of these rubber core-shell
nanoparticles
as binders for fiberglass mats. See, for example, the above-noted EP 2 053 083
Al, EP 5 830
086 B2 and U.S. 2005/0214534. In such use, however, the fiberglass binder is
composed
entirely of these rubber core-shell nanoparticles. In contrast, in some
exemplary aspects of
this invention, these rubber core-shell nanoparticles may be incorporated in
small but suitable
amounts as additives for improving the properties of a polymer resin which
forms the body of
the resin binder. According to some aspects of the present invention, the
amount of these
rubber core-shell nanoparticles included in the resin binder of the fiberglass
mat is about 0.1
to 20 wt.%, more typically about 0.5 to 10 wt.% or even about 1 to 4 wt.%,
based on the total
amount of the other polymer resins in the binder, i.e., excluding the weight
of the rubber
core-shell nanoparticles themselves.
[00066] It is also already known that the tensile strength of a solid polymer
mass (as
reflected by its fracture toughness, peel strength and lap shear strength) can
be enhanced by
including these rubber core-shell nanoparticles in the mass as fillers.
However, as indicated
above, tear strength and tensile strength do not correlate with one another in
the field of
asphalt roofing shingles. This is shown in Figs. 1 and 2, which are box plots
showing the
tensile strengths and tear strengths of fiberglass mats made with different
conventional
binders. See, also, Fig. 3, which is a similar box plot showing the tear
strength of asphalt
roofing shingles made with these different fiberglass mats. As shown in Fig.
1, the tensile
strength of the mat made with binder A was better than the tensile strength of
the mat made
with binder B. In contrast, both the tear strength of the mat made with binder
A (Fig. 2) and
the tear strength of the asphalt roofing shingle made with binder A (Fig. 3),
were worse than
the tear strengths of the mat and shingle made with binder B. This shows that
there is no
direct correlation between tear strength and tensile strength in asphalt
roofing shingles and
their associated fiberglass mats. This, in turn, demonstrates that the
improved tear strengths
of the inventive mats and shingles is a different phenomenon from the improved
tensile
strengths shown in the prior art.
[00067] The shell of the rubber core-shell nanoparticles used in this
invention can be formed
from essentially any thermoplastic or thermosetting polymer so long as it is
compatible with
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the polymer used to form the resinous binder of the fiberglass mat used in
this invention.
And by "compatible" is meant that the polymer forming the shell does not
adversely react
with the resinous binder, either by adversely affecting its physical or
chemical stability or
generating obnoxious or unwanted by product.
Additional Fiberglass Reinforced Composites
[00068] In accordance with other exemplary embodiments, fiberglass reinforced
composites
are formed by composite molding, wherein the glass reinforcing fibers and the
matrix
polymer are combined into a "prepreg" before being charged into the mold. Such
prepregs
can take the form of self-supporting objects in which the glass fibers are
randomly oriented,
such as the fiberglass sheets or "veils" used to form asphalt shingles. In
addition, they can
also take the foul' of self-supporting objects in which the glass fibers are
oriented in
predetermined directions, such as the three dimensional "skeletons" used to
foum load
bearing products of complex shape such as rocker arms for automobile
suspensions. Such
prepregs can also take the form of pellets, pastilles or agglomerates composed
of the matrix
polymer containing randomly distributed chopped glass fiber.
[00069] Specific examples of molding processes that can be used to make the
fiberglass
reinforced polymer composites of this invention include injection molding,
bladder molding,
compression molding, vacuum bag molding, mandrel wrapping, wet layup, chopper
gun
application, filament winding, extrusion molding, pultrusion, resin transfer
molding and
vacuum assisted resin transfer molding.
[00070] In accordance with some exemplary embodiments, the fiberglass
reinforced
polymer composite includes pressure-bearing vessels such as pipes (tubes) and
tanks formed
by filament winding or mandrel wrapping, especially products of this type in
which the
matrix polymer is an epoxy resin. Such products are well-known and described,
for example,
in U.S. 5,840,370 and U.S. 7,169,463, mentioned above. As described in these
patents, such
pressure bearing vessels are normally made by winding a continuous glass fiber
which has
been impregnated with some or all of the matrix polymer needed to form the
vessel around a
rotating steel mandrel in specific orientations. Any additional matrix polymer
is then added,
and the matrix polymer is then cured and the mandrel withdrawn, thereby
producing the
product vessel. Alternatively, such products can be made by wrapping a
preformed sheet or
veil of glass fibers, preimpregnated with some or all of the matrix polymer
needed to form
the vessel, around a stationary steel mandrel followed by adding additional
matrix polymer if
needed, curing the matrix polymer and withdrawing the mandrel. As further
described in
these patents, the glass fibers used to form such products are normally sized
during fiber
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manufacture with a binder size containing a lubricant, a film forming resin,
and a coupling
agent which is normally an organosilane.
[00071] In accordance with some exemplary aspects of this invention, core-
shell rubber
nanoparticles may be incorporated into the incipient size that is applied to
the glass fibers as
they are made. It has been discovered that incorporating these nanoparticles
onto the fibers in
this way is not only very convenient from a manufacturing standpoint but also
effective in
producing glass fibers with improved reinforcing properties when used in a
variety of
different fiberglass reinforced polymer composite applications.
[00072] Generally speaking, it is desirable in accordance with this invention
for the average
particle size of the core-shell rubber particles used in this invention to be
100 times smaller
(i.e., less than 1%) of the average diameter of the glass reinforcing fibers
to which they are
applied. Average particle sizes of 150 times smaller (i.e., less than 0.67%)
or even 200 times
smaller (i.e., less than 0.5%) of the glass reinforcing fibers are interesting
as well.
[00073] As explained above, it is known that the tensile strength of a solid
polymer mass (as
reflected by its fracture toughness, peel strength and lap shear strength) can
be enhanced by
including these core-shell rubber nanoparticles in the mass as fillers. See,
"Structure-
Property Relationship In Core-Shell Rubber Toughened Epoxy Nanocomposites," A
Dissertation by Ki Tak Gam Submitted to the Office of Graduate Studies of
Texas A&M
University in partial fulfillment of the requirements for the degree of Doctor
Of Philosophy
December 2003. However, as detailed above, the tear strength of an asphalt
roofing shingle
and its tensile strength do not correlate with one another. This demonstrates
that the
improved tear strengths of the asphalt roofing shingles made in accordance
with this
invention is a different phenomenon from the improved tensile strengths shown
in the prior
art.
[00074] In this regard, it should be appreciated that the tensile strength of
a solid polymer
mass is understood to be a function of its cohesive strength, i.e., the
ability of the mass to
hold itself together when under a tensile load. In contrast, the tear strength
of an asphalt
roofing shingle is understood to be a function of an entirely different
phenomenon, i.eõ the
ability of the binder size composition coating the glass fiber veil of the
shingle to promote
adhesion between the veil and the subsequently applied asphalt coating (matrix
polymer).
Furthermore, when core-shell rubber particles are used to improve the tensile
strength of a
solid polymer mass, enough of these nanoparticles are used to fill the entire
polymer mass. In
contrast, a much smaller amount of core-shell rubber nanoparticles is used in
this invention,
since these nanoparticles are present only on the surfaces of the glass fibers
themselves and
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are not distributed in the mass of matrix polymer forming the body of the
inventive fiberglass
reinforced polymer composites.
[00075] In accordance with this invention, the core-shell rubber nanoparticles
of this
invention can be applied to the glass reinforcing fibers anytime prior to the
application of the
matrix polymer forming the body of the inventive fiberglass reinforced polymer
composites.
So, for example, the core-shell rubber nanoparticles can be applied to the
glass reinforcing
fibers in a binder size after they are made and stored, in a separate
application step as part of
the manufacturing process for producing the fiberglass reinforced polymer
composites of this
invention.
[00076] Alternatively, they can be applied to the glass fibers "in-line"
during fiberglass
manufacture as part of the glass fiber manufacturing process itself. Normally,
this will be
done by including these core-shell rubber nanoparticles in the incipient size
composition
applied to the individual glass filaments used to form the glass fiber, before
these filaments
are combined together to form the fiber. Alternatively, these core-shell
rubber nanoparticles
can be applied to the glass fibers after they are formed in a separate aqueous
size
composition. For convenience, these separate size compositions are referred to
in this
document as "secondary incipient sizes." In a third approach, both of these
procedures can
be used, some the core-shell rubber particles being applied to the individual
filaments in the
incipient size before the glass fibers are formed and the remainder being
applied in a
secondary incipient size after the fibers are formed.
[00077] Regardless of which of these approaches is used, in-line application
enables these
core-shell rubber particles to be conveniently applied during glass fiber
manufacture, which
in turn eliminates the need for a separate "off-line" process step during
subsequent
manufacture of the inventive fiberglass reinforced polymer composites. In
addition, in-line
application of the core-shell rubber nanoparticles can reduce the amount of
film-forming
polymer that is ultimately applied to the glass fibers, at least when the
nanoparticles are
included in the incipient size composition used during fiber manufacture. This
is because, to
promote adhesion of the core-shell rubber nanoparticles to the glass fibers,
the nanoparticles
should be applied together with a film-forming polymer. Therefore, combining
these
nanoparticles with the incipient glass size eliminates the need for a second,
subsequent film-
forming resin coating.
[00078] As indicated above, the core-shell rubber nanoparticles of this
invention may be
applied to glass fiber or filament substrates together with a suitable film
forming resin. For
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this purpose, any film forming resin which has previously been used or may be
used in the
future as a film forming resin in a glass fiber and/or filament size may be
suitable for use.
[00079] As appreciated in the art, it is conventional practice when selecting
the film fowling
resin to be used in an incipient size or a binder size to select a resin which
is compatible with
the matrix resin that will be used to make the fiberglass composite ultimately
being produced.
For example, if a particular fiberglass composite is to be made with an epoxy
resin matrix,
then a compatible epoxy resin will normally be selected as the film farming
resin for the glass
fiber size. This same customary practice is followed in accordance with this
invention, i.e.,
the film forming resin used in the size containing the core-shell rubber
nanoparticles of this
invention is desirably selected to be compatible with the matrix resin of the
fiberglass
reinforced polymer composite being produced
[00080] As further indicated above, this invention finds particular use in
making fiberglass
reinforced polymer composites from epoxy resins, because of the superior
physical properties
(e.g., ensile strength) and chemical resistance of these polymers. For this
purpose, in some
exemplary embodiments, it is desirable to select as the film forming resin in
the size
containing the core-shell rubber particles, a linear bisphenol A type epoxy
resin of moderate
molecular weight. In this context, "moderate molecular weight" means a weight
average
molecular weight of about 10,000 to 250,000. Weight average molecular weights
of 15,000
to 100,000 or even 20,000 to 50,000 are preferred. Linear bisphenol A type
epoxies are
desirable because many fiberglass reinforced polymer composites, and
especially those
requiring high strength and good chemical resistance, are made from linear
bisphenol A type
epoxy matrix resins. These molecular weights are desirable, because the epoxy
resin will not
effectively form a film if its molecular weight is too high and will undergo
unwanted
crystallization in the coating equipment if its molecular weight is too low.
[00081] In addition to linear bisphenol A type epoxies, modified epoxy resins
can also be
used. For example, epoxy novolacs can also be used.
[00082] Specific examples of commercially available epoxy resins which are
useful as the
film forming resin to be used together with the core-shell rubber
nanoparticles of this
invention are AD-502 epoxy aqueous emulsion from AOC, Neoxil 962/D aqueous
emulsion
from DSM, EpiRez 5003 from Momentive, EpiRez 3511 epoxy emulsion from
Momentive.
Blends also are effective, especially AD-502 + EpiRez 5003 in a 95:5 ratio.
[00083] The amount of film forming resin that can be present in the aqueous
size containing
the core-shell rubber nanoparticles of this invention can vary widely, and
essentially any
amount can be used that will provide an effective coating composition.
Typically, the
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amount of film forming resin will be about 60 to 90 wt.% of the aqueous size
on a dry solids
basis (i.e., excluding water). Concentrations on the order of about 65 to 85
wt.%, or even 73
to 77 wt.%, on a dry weight basis are preferred.
Sizes with Combination Particles
[00084] As indicated above, the aqueous size containing the core-shell rubber
nanoparticles
of this invention may also contain a film forming resin. While each of these
ingredients can
be separately supplied to and contained in this aqueous size composition, in a
particularly
interesting embodiment of this invention these ingredients are combined
together in the
emulsified particles contained in this aqueous size composition.
[00085] Core-shell rubber nanoparticles are commercially available in a
variety of different
fomis. One such form is an organic emulsion of the rubber nanoparticles
dispersed in neat
(i.e., solvent free) liquid epoxy resin. Examples of these products include
the Kane AceTM
MX line of CSR Liquid Epoxy Emulsions available from Kaneka Belgium NV. These
liquid
epoxy/rubber nanoparticle emulsions comprise stable dispersions of about 25 to
40 wt.%
CSR (core shell rubber nanoparticles) in various different kinds of liquid
epoxy resin system
including bisphenol-A type liquid epoxy resins, bisphenol-F type liquid epoxy
resins,
epoxidized phenol novolac type liquid epoxy resins, triglycidyl p-aminophenol
type liquid
epoxy resins, tetraglycidyl methylene dianiline type liquid epoxy resins, and
cycloaliphatic
type liquid epoxy resins. They are well known articles of commerce which have
been
previously used for toughening epoxy and other matrix resins, including matrix
resins used
for forming fiberglass reinforced polymer composites such as filament wound
pipes and the
like.
[00086] In this regard, it should be remembered that a significant difference
between this
invention and prior technology for making fiberglass reinforced composites
containing core
shell rubber nanoparticles is that, in this invention, the core shell rubber
nanoparticles are
coated onto the glass reinforcing fibers of the composite before these fibers
are combined
with the matrix resin fanning the body of the composite. This is completely
different from
earlier technology in which the core shell rubber nanoparticles are dispersed
throughout the
entire mass of matrix resin. Thus, a difference between this invention and
prior technology in
connection with using these commercially available liquid epoxy core shell
rubber
nanoparticle emulsions is that, in this invention, these emulsions are used to
form the
incipient size that is coated onto the glass fibers before these fibers are
combined with the
matrix resin. In contrast, in earlier technology, these emulsions are used to
fouli the matrix
resin itself.
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[00087] These commercially available liquid epoxy/rubber nanoparticle
emulsions represent
a convenient source of the core-shell rubber nanoparticles of this invention,
because they
already contain two major ingredients of the incipient sizes of this
invention, i.e., the core
shell rubber particles and the epoxy resin film former.
[00088] According to some exemplary embodiments, before these commercially
available
liquid epoxy/rubber nanoparticle emulsion can be used to make the incipient
sizes of this
invention, they are converted into aqueous emulsions. This can easily be done
by using
conventional high shear emulsification techniques. For example, a rubber
nanoparticle
aqueous size composition in which the weight ratio of rubber nanoparticles to
epoxy resin is
25/75 can be made by emulsifying an organic emulsion containing 25 wt.% rubber
nanoparticles and 75 wt.% liquid epoxy resin using conventional high shear
mixing
techniques and conventional epoxy-suitable surfactants such as ethylene
oxide/propylene
oxide block copolymers.
[00089] The amount of core-shell rubber particles that will be applied to a
glass fiber or
filament substrate in accordance with this invention will typically represent
about 0.01 to 25
wt.% of the solids content of the aqueous size compositions in which they are
contained.
More commonly, the amount of core-shell rubber particles will be about 0.1 to
5 wt.%, about
0.3 to 2 wt.%, about 0.5 to 1.5 wt.%, or even about 0.7 to 1.3 wt.% of these
solids.
Accordingly, the rubber nanoparticle aqueous size compositions of this
invention will
typically be made by combining at least two different aqueous resin
dispersions, one whose
emulsified resin particles contain a combination of film forming resin and
core-shell rubber
nanoparticles, the other whose emulsified resin particles contain only the
film forming resin.
Additional Ingredients
[00090] In addition to the film forming resin, the aqueous size composition
containing the
core-shell rubber nanoparticles of this invention can also contain various
additional optional
ingredients.
[00091] For example, these aqueous size compositions may contains about 5 to
30 wt.%,
more commonly about 8 to 20 wt.% or even about 10 to 15 wt.% of an
organosilane coupling
agent based on the solids content. For this purpose, any organosilane coupling
agent that has
previously been used or may be used in the future for enhancing the bonding
strength of a
film forming binder resin to a glass fiber substrate can be used in this
invention. In addition,
as in the case of the binder resin, the organosilane coupling agent should be
selected to be
compatible with the particular film forming binder resin being used.
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[00092] Specific examples of useful organosilane coupling agents are Silquest
A-1524
ureidosilane, Silquest A-1100 aminosilane, Silquest A-1387 silylated
polyazimide in
methanol, Y-19139 silylated polyazimide in ethanol from Momentive, Silquest A-
174
methacryloxysilane, Silquest A-187 epoxy silane, Silquest A-1170 trimethoxy
bis-silane,
Silquest A-11699 triethoxy bis-silane, all from Momentive and Silquest A1120.
Silquest A-
1524 as well as blends of Silquest A-1387 and Silquest A-1100 are preferred
for use with
epoxy resin film forming resins.
[00093] Another ingredient that can be included in the rubber nanoparticle-
containing
aqueous size compositions used in this invention is a lubricant. Examples of
commercially
available lubricants that are suitable for this purpose include Katex 6760
(also known as
Emery 6760) cationic lubricant, PEG400 monooleate (PEG400 MO, Emerest 2646),
PEG-
200 monolaurate (Emerest 2620), PEG400 monostearate (Emerest 2640), PEG600
monostearate (Emerest 2662). Cationic lubricants such as Katex 6760 are
typically used in
amounts from 0.001 to 2 wt,%, more typically 0.2 to 1 wt.%, or even about 0.5
wt.%, of size
solids. Meanwhile, PEG lubricants are typically used in amounts of 0.1 to 22
wt.%, more
typically about 1 to 10 wt.%, or even about 7 wt.% of solids content.
[00094] Yet another conventional lubricant that can be included in the rubber
nanoparticle-
containing aqueous size compositions used in this invention is a wax. Any wax
which has
been or may be used as a lubricant wax in a glass fiber aqueous sizing
composition can be
used as the wax in the rubber nanoparticle aqueous size compositions of this
invention.
Michelman Michemlube 280 wax is a good example. Concentrations on the order of
about
0.1 to 10 wt% of size solids are useable, while concentrations of about 2 to 6
wt% or even 4
to 5 wt% are preferred.
[00095] Still other conventional ingredients that can be included in the
rubber nanoparticle-
containing aqueous size compositions of this invention include acetic, citric
or other organic
acid in an amount sufficient to efficiently hydrolyze the silanes that are
present, which
typically requires a pH of about 4-6 in the case of Silquest A-1100. Final
size pH will
typically be in the 5 ¨ 6.5 range.
[00096] Other additives such as Coatosil MP 200 multifunctional epoxy
oligomer, aqueous
urethane polymers such as Michelman U6-01 or Baybond PU-403 from Bayer, Witco
W-296
or W-298 from Chemtura or and the like can also be included in the rubber
nanoparticle-
containing aqueous size compositions of this invention for their known
functions in
conventional amounts.
Water Content and Loadings
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[00097] The rubber nanoparticle-containing aqueous size compositions of this
invention are
applied to their glass fiber and/or filament substrates in a conventional way
using
conventional coating equipment. Therefore, they are formulated with sufficient
amounts of
water so that their rheological properties are essentially the same or at
least comparable to
that of conventional aqueous sizes. Accordingly, these aqueous size
compositions will
typically contain a total solids content of about 2 to 10 wt.%, more commonly
4 to 8 wt.% or
even 5 to 7 wt.%, based on the total weight of the aqueous size composition.
[00098] In addition, these nanoparticle-containing aqueous size compositions
are also
applied to their glass fiber and/or filament substrates in conventional
amounts. For example,
these size compositions will normally be applied in amounts such that the LOT
(loss on
ignition) of the sized glass fibers and filaments obtained is about 0.2 to 1.5
%, more typically
0.4 to 1.0 % or even 0.5 to 0.8%. Inasmuch as the concentration of core-shell
rubber
nanoparticles in these sizes will typically be on the order of about 0.3 to 2
wt.%, about 0.5 to
1.5 wt.%, or even about 0.7 to 1.3 wt.% on a dry solids basis, this means that
the amount of
these core-shell rubber nanoparticles that will be applied to their glass
fiber and/or filament
substrates in terms of LOT will normally be about 0.001 to 0.015%, more
typically about
0.002 to 0.010% or even about 0,0025 to 0.0080%.
WORKING EXAMPLES
[00099] In order to more thoroughly describe this invention, the following
working
examples are provided.
Example 1 and Comparative Example A
[000100]Two fiberglass mats were made by a conventional wet laid coating
process in which
wet chopped glass fibers, after being deposited onto a moving screen from an
aqueous slurry,
were coated with an aqueous dispersion of a resin binder and then dried and
cured. The resin
binders applied to both webs were each prepared using a commercially-available
acrylic latex
(Rhoplex GL 720 available from Dow Chemical) and a commercially-available urea
formaldehyde resin latex (FG 654A available form Momentive). The amounts
resins applied
were selected so that the weight ratio of acrylic resin to urea formaldehyde
resin in both
binders was the same on a dry solids basis (15/85) and further so that the
total amount of
binder applied to each web was essentially the same. The resin binder of
Example 1 also
included 1.7 wt.%, based on the combined weights of urea formaldehyde and
acrylic resins
in the binder, of a commercially-available rubber core-shell nanoparticles, in
particular Kane
Ace MX-113 rubber core-shell nanoparticles available from Kenaka Corporation
of
Pasadena, Texas.
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[000101]The fiberglass mats so obtained were then tested for tensile strength
and tear
strength in the cross or transverse direction. Because fiberglass mats and
their associated
asphalt roofing shingles are generally weaker in their transverse direction
than in their
machine direction, tensile and tear strengths in the transverse direction give
a better
indication of the overall strength of the product.
[000102]In addition to these tests, the tear strengths of these fiberglass
mats in the transverse
direction was also determined by a rock dusted mat perfolidance test. In this
test, each mat
was first dusted with the same amount of a powdered rock and then measured for
tear
strength in the transverse direction. This test was used, because it provides
a good simulation
of the adverse effect on fiberglass mat properties that can be caused by the
inorganic
particulate fillers contained in a subsequently applied asphalt coating. This
rock dust mat
perfon __ lance test was carried out three times for each sample, with the
average values
obtained for each test being reported below.
[000103] The results obtained are set forth in the following Table 1:
TABLE 1
Tensile and Tear Strengths of Fiberglass Mats of Example 1 and Comparative
Example A
Transverse Transverse
Transverse Tear (no Tear (rock Tear Retention(%):
BW LOI Tensile rock dust) dusted) (RD tear/tear no
RD)
Comp Ex A 1,82 19.1 73 466 306 66
Ex 1 1.81 18.8 71 633 , 488 77
[000104]In the above table, "BW" refers to basis weight, which is the weight
of cured mat
(fiberglass plus cured binder) pounds per 100 square feet. Meanwhile, "LOI"
refers to loss
on ignition, which is a standard measure in this industry indicating the
portion of the aqueous
binder originally applied to the web, in percent, which remains on the web
after the binder
has dried and cured. The total amount of binder applied to the web after
drying and curing,
i.e., on a dry solids basis, can be determined by multiplying BW by LOT.
[000105]As can be seen from Table 1, the presence of rubber core-shell
nanoparticles in the
binder of Example 1 caused essentially no effect on the tensile strength of
the fiberglass mat
made from this binder (the difference in Table 1 is within the experiment
error), but the tear
strength of this mat to increase, in the transverse direction relative to the
control fiberglass
mat of Comparative Example A. In addition, Table 1 also shows that, while rock
dusting
caused a significant decrease in the tear strength of both mats, this decrease
was more
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pronounced in the case of Comparative Example A. Specifically, Table 1 shows
that the
presence of these rubber core-shell nanoparticles enabled the mat of Example 1
to retain 77%
of its original tear strength, whereas the mat of Comparative Example A
retained only 66% of
its original tear strength, when both mats were rock dusted.
[000106] This data shows that the addition of these rubber core-shell
nanoparticles improves
the tear strength of fiberglass mats in the transverse direction, not only in
an "as-made"
(uncoated) condition but also in a simulated use condition.
Example 2 and Comparative Example B
[000107] Eight additional mats were prepared, four representing this invention
and four being
controls in which no rubber core-shell nanoparticles were used. These mats
were made using
the same procedures and ingredients as used in Example 1, except that the
amount rubber
core-shell nanoparticles included in the binders representing this invention
was 1.85 wt.%.
[000108]Each fiberglass mat obtained was then formed into an asphalt roofing
shingle by
coating the mat with an asphalt coating composition made from of a coating
asphalt, the
asphalt coating composition also containing 65 wt.% based on the asphalt
coating
composition as a whole of a calcite inorganic particulate filler.
[000109] The tensile strength of each roofing shingle in the machine direction
was measured,
as was the tear strength of each roofing shingle in both the machine and
transverse directions.
In addition, the total tear strength of each roofing shingle was determined by
adding the
machine and transverse tear strengths together. Finally, these measured tear
and tensile
strengths were nounalized by shingle weight.
[000110] The results obtained are set forth in the following Table 2.
TABLE 2
Tensile and Tear Strengths of Roofing Shingles of Example 2 and Comparative
Example B
Machine MD Transverse
Tensile Tear Total Tear
Comp Ex B 192 1870 3317
Ex 2 185 2037 3615
% of Change -3.65 8.93 8.98
[000111]Table 2 shows that adding rubber core-shell nanoparticles to the
binder of a
fiberglass mat used to make an asphalt roofing shingle imparts essentially the
same effect on
the shingle as it imparts on the mat. In particular Table 2 shows that, like
the fiberglass mats
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of Example 1, asphalt shingles made with these nanoparticles exhibit
significantly greater
tear strengths in the transverse direction than control shingles made without
these
nanoparticles. In addition, Table 2 further shows that these nanoparticles
also cause a slight
decrease in the tensile strength of these shingles, in this case in the
machine direction rather
than in the transverse direction as reported in Example 1 above.
Example 3
[000112]In the following examples, filament wound high pressure composite
pipes were
made by winding around a mandrel glass fibers having previously been
impregnated with a
commercially available aqueous epoxy matrix resin dispersion. The winding so
formed was
then heated to cure the epoxy matrix resin and the mandrel then withdrawn to
produce the
final product pipe.
[000113] The glass fibers used to make each composite were made by a
conventional glass
fiber manufacturing process as described above in which the attenuated glass
filaments, prior
to being combined into fiber, were coated with an incipient size. Three
different experiments
were done. In the first experiment representing the prior art, the incipient
size contained no
core-shell rubber nanoparticles. In the remaining two experiments, the
incipient size
contained 0.5 wt.% core-shell rubber nanoparticles and 1 wt.% core-shell
rubber
nanoparticles, respectively.
[000114]The amount of incipient size applied to each glass fiber is set forth
in the following
Table 3, while the specific composition of each incipient size is set forth in
the following
Table 4.
TABLE 3
Size Loadings
Example % Rubber LOI, % Yardage, T Tex,
Particles in Size Yards/pound ------------------------------- g/kg
Control 0 0.55 243.98 2033.20
4 0.5 0.57 251.74 1970.51
1.0 0.63 251.69 1970.94
TABLE 4
Chemical Composition of Incipient Sizes
Ingredient Concentration, wt .% solids
Identity Function Control Example 1
Example 2
Citric Acid pH control i
0.53 0.53 tO.53J
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Uredosilane Coupling 13.02 13.031 13.04
agent
Aqueous Epoxy 77.46 76.42 73.42
Resin Emulsion
Aqueous 10 2.01 4.00
Nanoparticle
Emulsion*
1- PEG 400 Lubricant 3.89 3.92 3.92
Wax Lubricant r 4.69 4.70 4.70
_11
Cationic Lubricant Lubricant 0.39 0.39 0.39
* Aqueous emulsion of Kaneka's Kane AceTM MX-125 epoxy emulsion containing 75
wt.% epoxy resin and 25 wt.% core shell rubber nanoparticles
[000115] The filament wound composite pipes so obtained were subjected to two
different
analytical tests. In the first, the burst strength of the product pipes
obtained was determined.
In the second, the interlaminar shear strength (ILSS) of the product pipes
when exposed to
boiling water for 500 hours was determined in accordance with the NOL Ring
Test Method,
Accession No. AD0449719, Naval Ordinance Laboratory, White Oak, Maryland. In
addition
to these analytical tests, during manufacture of each pipe, the tension
generated on the glass
fibers used to make the pipes during the winding operation was deteiniined and
recorded.
The results obtained are set forth in Figs. 3-6.
[000116] As shown in Fig. 3, the burst strengths of the inventive product
pipes were about 8-
11% greater than the burst strength of the control pipe. This shows that the
core-shell rubber
nanoparticles of this invention provide a substantial improvement in the
mechanical
properties of glass fiber reinforced polymer composites made in accordance
with this
invention.
[000117]Meanwhile, Fig. 4 shows that the core-shell rubber nanoparticles of
this invention
imparted essentially no adverse effect on the interlaminar strength of the
inventive product
pipes after 500 hours of exposure to boiling water. This suggests that the
core-shell rubber
nanoparticles of this invention do not adversely affect the chemical
resistance of the inventive
glass fiber reinforced polymer composites in any significant way.
[000118]Finally, Fig. 5 shows that tension generated on the glass fibers
during the winding
operation used to form the inventive filament wound composite pipes was
essentially
unaffected by the core-shell rubber nanoparticles of this invention. This
shows that the core-
shell rubber nanoparticles of this invention do not adversely affect the
manufacturing process
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used to produce the inventive glass fiber reinforced polymer composites in any
significant
way.
1000119)Although only a few embodiments of this invention have been described
above, it
should be appreciated that many modifications can be made without departing
from the spirit
and scope of this invention. For example, it is possible and even desirable in
some instances
to combine the core-shell rubber nanoparticle technology of this invention
with other
technologies for making fiberglass reinforced polymer composites.
[000120]For example, the above-mentioned commonly assigned U.S. 5,840,370
describes a
process for making a glass/polymer prepreg in which application of some or all
of the matrix
polymer forming the ultimate fiberglass reinforced polymer composite is
applied "in-line" as
part of the glass manufacturing process.
That technology can be combined with the
technology of this invention by applying the core-shell rubber nanoparticles
of this invention
first, followed by impregnating the coated glass fibers so formed with the
matrix polymer of
the polymer composite second.
[000121]All such modifications are intended to be included within the scope of
this invention
and the related general inventive concepts, which are to be limited only by
the following
claims.
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