Note: Descriptions are shown in the official language in which they were submitted.
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GLASS-MICROSPHERE COATED ARTICLE HAVING A SMOOTH SURFACE AND METH00 FOR
ITS PREPARATION
FIELD OF THE INVENTION
This invention relates to glass microsphere (bead) coated articles having an
upper surface comprising a layer oflow refractive index transparent glass
microspheres such as those made from recycled ordinary glass. The articles
ofthe
invention have an extremely smooth tactile feel and a low friction surface
even
though they can be prepared from glass microspheres intermixed with abrasive
irregularly shaped glass particles.
More specifically, the invention relates to sheets, fabrics or decorated
articles, which have a surface layer of small diameter glass microspheres
having
exposed hydrophilic surfaces. The articles ofthe invention can be prepared by
the
method of the invention which minimizes the abrasive effects of the optionally
broad
size range distribution ofthe glass microspheres plus the irregularly-shaped
non-
spherical particles which are intermixed therewith.
The surface ofthe bead coated articles ofthe invention can possess a
combination of desirable properties, such as low gloss, accurate color
transmission,
good abrasion resistance, optional wide observation angle retroreflectivity,
and a
slippery feeling surface that does not stick to the skin when moistened by
rain,
perspiration, or the like.
The invention also relates to the method making the bead coated articles of
the invention and transfer articles that can be used to make the bead coated
articles
of the invention.
BACKGROUND OF THE INVENTION
It is well known to coat the surface of sheets with transparent glass
~ microspheres to provide retroreflection, decoration and improved resistance
to
abrasion, weather and water. For example, Gebhard et al. in U. S. Patent No.
2,326,634, teaches that maximum brilliancy in reflex-reflection is achieved in
exposed lens transparent glass bead structures through use of expensive high
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refractive index glass beads in the range of 1.7-1.9, which lies far above the
refractive index range of 1.5-1.55 of ordinary glass. No reference was made to
any
irregularly shaped glass particles intermixed with the beads. A reflecting
binder layer
was disposed under the half exposed glass beads to achieve reflex-reflection.
To
make the reflex-reflecting sheet the beads were coated over a soft, tacky
under
cured binder which was subsequently cured, during which the beads became
embedded to roughly one-half of their diameters. The beads varied in size,
with the
larger beads projecting out ofthe binder surface more than the smaller beads.
Lovell teaches in U.S. Patent No. 3,764,455 a retroreflective surface of
exposed glass beads for coating the sides of elastomeric articles such as
tires by
sprinkling glass beads of 50-300 micrometers on the surface of an elastomeric,
pigment containing adhesive while it is still in an adhesive state. No
reference was
made to the refractive index of said glass beads. No reference was made to any
irregularly shaped glass particles intermixed with the beads. Examples were
provided using smaller beads which were lower in retroreflection because they
tended to become encapsulated by the resin into which they were sprinkled.
Berg teaches in U.S. Patent No. 3,172,942 a reflex-reflecting transfer film
whicli is provided with a dry strippable carrier on its reflex-reflecting face
for
bonding a mono-layer ofhigh refractive index glass beads to fabrics, followed
by
removal of the Garner to expose the surface of the embedded glass spheres.
Examples were provided where the structure was made in reverse fashion upon a
removable carrier, wherein the Garner had a meltable plastic coating in which
the
glass beads could be embedded temporarily to roughly one-half their diameters
and
subsequently coated with an elastomeric binder. The refractive index of the
glass
beads was specified to the 1.7-1.9 criteria. No reference was made to any
irregularly shaped glass particles intermixed with the glass beads.
Bingham, in U.S. Patent No. 3,758,192, taught a retroreflective sheet
structure using a particular transfer method which also provided diffuse and
retroreflected color by disposing a dispersion of a reflective nacreous
pigment in a
substantially transparent binder which contained colored pigment on the buried
side
ofthe glass beads. Bingham's examples again were focused on high refractive
index
glass beads of 1.9. No reference was made to any irregularly shaped glass
particles
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3
intermixed with the beads. Bingham further taught in U. S. Patent No.
3,700,305 a
sheet material which used a transparent, substantially color-free vapor
deposited
mufti-layer dielectric mirror coating on the buried side ofthe glass beads
which
would allow good color transmission ofpigmented layers buried below the
reflector
coat. Typically, this dielectric mirror would retroreflect the color of the
incident
light. However, this reflector coat was also capable ofretroreflective color
when
the dielectric layers were properly chosen and spaced to act as a visible
light pass
band filter.
In both Bingham and Berg, graphic images were disposed on a separate
substrate by die-cutting an image from the described sheet material and
separately
bonding the same to a substrate. Harper, in U.S. Patent No. 4,102,562,
describes a
more convenient retroreflective imaged transfer sheet wherein the beads were
transferred image-wise, after printing a portion of the bead-coated transfer
sheet
with an ink that was also an adhesive. A transparent dielectric reflecting
layer was
deposited on the surface ofthe glass beads before printing the ink/adhesive
image,
so the color of the ink was visible under daytime viewing. However, this
method
results in no transmission ofprinted ink/adhesive color under retroreffective
conditions. Harper's examples again used expensive high refractive index
glass.
Harper makes no reference to glass beads intermixed with irregularly shaped
glass
particles.
Olsen, in U.S. Patent No. 5,344,705, overcame a limitation ofHarper by
providing a transfer image structure which would retrorefiect more than one
color
by printing a second ink containing nacreous reflecting particles on a first
transparent colored layer, followed by printing an adhesive transfer layer.
Again,
his specification and examples focused on expensive high refractive index
glass
beads. Again, Olsen makes no reference to glass beads intermixed with
irregularly
shaped glass particles
Ueda, et al. discloses, in U.S. Patent No. 4,849,265, a decorative, protective
beaded sheeting with exposed glass beads, formed by disposing the beads on a
flexible substrate having an adhesive thereon in a tacky state, pressing the
beads into
the adhesive to flatten the outer surface, and subsequently curing the same.
Ueda
makes no reference to glass beads intermixed with irregularly shaped glass
particles.
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The claimed construction provides a thin~flexible over-coating which maintains
the
spherical shape of the surface. This surface coating over the beads is present
to
reduce noise and increase resistance to sliding of hard objects placed and
moved
thereon. This surface coating, however, covers the natural hydrophilic
character of
the glass surface. Thus, Ueda et al. utilizes glass beads for decoration and
protection. The method of Ueda et al., however, does not lead to articles
comprising low refractive index glass beads and irregularly shaped glass
particles
having a low friction surface of smooth tactility.
SUMMARY OlH' THE INVENTION
We have discovered a unique bead coated article which can be prepared
from low refractive index transparent glass beads, especially the economical
glass
beads available from the recycling of ordinary glass which are intermixed with
a
number of irregularly shaped glass particles.
In addition to their potential decorative and protective properties the bead
coated articles of the invention surprisingly have a low fiaction surface with
a
smooth tactility against skin, which feels like silk.
Furthermore, the glass bead coated surface of the article of the invention has
a hydrophilic surface even when using an adhesion promoter. This surface has
been
found to retain a large portion ofits slipperiness against skin when it is wet
with
water or dampened by perspiration which broadens its utility to include use in
seating materials, clothing linings, orthopedic devices, and the like.
The glass bead coated surface of the bead coated article of the invention
may or may not exhibit retroreflectivity, depending on whether a suitable
material
such as pigments) are present in the article beneath the glass beads and the
type of
materials) selected. Optionally some areas of the surface of the article of
the
invention may exhibit a retroreflective character, while other areas do not.
In the bead coated articles ofthe present invention the low refractive index
glass beads are exposed such that the apex of each bead is at or about the
same
level, even when a fairly broad distribution of bead diameter is used in the
bead
layer population.
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s
Glass beads prepared from recycled low refractive index (i.e., about 1.5 to
about 1.6 refractive index) glass typically contain an amount of irregularly
shaped
glass particles. These irregularly shaped and abrasive glass particles present
in the
population of glass beads are partially embedded in the glass bead adhesive
layer of
the bead coated article ofthe invention such that the irregularly shaped
particles do
not extend to a substantial extent, (preferably not at all) above the apex
ofthe beads
such that the bead coated article surface has the requisite smoothness (as
measured
by the coefficient of friction). The specular surfaces of these irregularly
shaped
particles further enhance the appearance of the bead coated articles of the
invention.
The low refractive index of the glass beads and irregularly shaped glass
particles intermixed therewith used according to the invention would be closer
to
the refractive index ofthe available bead adhesive materials used to hold the
beads
in place (as opposed to high refractive index glass beads which differ more in
refractive index from the bead adhesive in which they are typically embedded)
thus
providing superior color transmission of any buried graphic layers.
If the bead coated article of the invention is additionally designed to
exhibit
at least some retroreflection by virtue ofhaving a reflecting layer in a
cupped
configuration behind (i.e. over the unexposed surfaces ofthe glass beads), the
resulting retroreflection has a lower level but broader observation angle than
if the
bead coated articles of the invention used high refractive index beads rather
than
low refractive index beads. By "a cupped configuration" it is meant that the
reflecting layer conforms to the unexposed glass bead surfaces. Ifthe
reflecting
layer behind (i.e. over the unexposed surfaces of) the low refractive index
glass
beads is an ink layer containing nascent particles and transparent pigment,
the
retroreflected color is closer to the actual color of the ink layer than if
the article of
the invention used high refractive index beads rather than low refractive
index
beads. Both of these properties are important in accurately preserving the
graphic
intent of bead coated articles of this invention intended for decoration.
Further, the bead coated article ofthe invention may have both
retroreflective images) and non-retroreflective image(s), the article ofthe
invention
still having its ultra-smooth surface tactility.
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The present invention thus provides a bead coated article comprising:
(a) a first adhesive layer;
(b) a layer of a mixture of transparent glass beads intermixed with
irregularly
shaped glass particles, said m'vcture optionally treated with an adhesion
promoter,
wherein the layer of glass beads and irregularly shaped glass particles are
partially
embedded in the first adhesive layer such that about 20% to about 70% ofthe
average diameter ofthe glass beads is exposed, wherein the first adhesive
layer is
capable of adhering to the mixture ofthe glass beads and the irregularly
shaped
glass particles;
wherein the average cross-sectional diameter of the mixture of the glass
beads and the irregularly shaped glass particles, for at least 95 percent by
weight of
the mixture ranges from about 20 microns to about 180 microns;
wherein at least 95% by weight ofthe total number of glass beads and
irregularly shaped glass particles fall within a threefold range such that the
smallest
and largest cross-sectional diameters differ by a factor of about 3 or less;
wherein the bead coated article comprises at least about 3% irregularly
shaped glass particles by average count per unit area ofthe glass bead coated
article
based on the average total count per unit area of the glass bead coated
article of the
glass beads plus the irregularly shaped glass particles, wherein the aforesaid
average
count of irregularly shaped glass particles is based on irregularly shaped
glass
particles having a cross-sectional diameter equal to or greater than the
smallest
cross-sectional diameter in the threefold range;
wherein the glass beads and irregularly shaped glass particles have refractive
indices
ofbetween about 1.5 and about 1.6;
wherein the glass beads and irregularly shaped glass particles are positioned
such that the coefficient of friction of a planer surface of the first
adhesive having a
continuous layer ofthe glass beads and irregularly shaped glass particles
embedded
therein is less than about 0.3.
The invention further provides a bead coated article ofthe invention wherein
the bead adhesive layer is transparent and sufficiently thin such that it
conforms to
the spherical shape of the glass beads embedded therein.
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The invention further provides a bead coated article of the invention wherein
the bead adhesive layer is either a continuous layer or a discontinuous layer
(in the
form of an image) and the adhesive layer is bonded to a substrate (which may
be
rigid or flexible, for example) by virtue of a substrate adhesive (which may
be
continuous or discontinuous) between the substrate and the surface of the
adhesive
layer opposite the layer of embedded glass beads. Optionally, however, a
substrate
adhesive layer can be used to bond the colored polymeric layer to the
substrate.
The invention further provides an article wherein one or more colored
polymeric layers such as ink layers is(are) disposed in the form of an images)
between the transparent bead adhesive layer (which is optionally a conforming
layer) and the substrate. Within this embodiment is envisioned the option
wherein a
colored polymeric layers) can function as a substrate adhesive.
The invention further provides an article of the invention wherein the bead
adhesive layer is optionally pigmented.
The bead coated article ofwhich comprise about 3% to about 15% or about
5% to about 15% or about 6% to about 12% irregularly shaped glass particles by
average count per unit area ofthe glass bead coated article based on the
average
total count per unit area of the glass bead coated article of the glass beads
plus the
irregularly shaped glass particles is also provided.
The bead coated article wherein the layer of glass beads intermixed with
irregularly shaped particles is in the form of an image is also provided.
The bead coated article wherein the first adhesive layer is also a substrate
adhesive and is bonded to a substrate on a side opposite the layer of embedded
glass
beads and irregularly shaped glass particles is also provided.
The present invention also provides a transfer article, wherein the transfer
article of the invention can be used to make the bead coated article of the
invention.
The transfer article of the invention comprises:
(a) a transfer carrier, the transfer carrier comprising:
(i) a support layer; and
(ii) a thermoplastic glass bead release layer bonded to the support
layer;
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(b) a layer of a mixture of transparent glass beads and irregularly shaped
glass particles, the mixture optionally treated with an adhesion promoter,
formed on
a side of the thermoplastic glass bead release layer opposite the support
layer, such
that the glass beads are embedded to between about 20% and about 70% of their
average diameter in the thermoplastic glass bead release layer and at least
some of
the irregularly shaped glass particles are partially embedded in the
thermoplastic
glass bead release layer and some of the irregularly shaped glass particles
are
optionally, completely embedded in the thermoplastic glass bead release layer;
wherein at least 95% by weight ofthe total number ofglass beads and
irregularly shaped glass particles fall within a threefold range such that the
smallest
and largest cross-sectional diameters differ by a factor of about 3 or less;
wherein the average cross-sectional diameter ofthe mixture ofthe glass
beads and the irregularly shaped glass particles, for at least 95 percent by
weight of
the mixture ranges from about 20 microns to about 180 microns;
wherein the glass beads and irregularly shaped glass particles have refractive
indices of about 1.5 to about 1.6;
(c) a layer of a first adhesive, capable of adhering to the layer of the
mixture
ofthe glass beads and the irregularly shaped glass particles, the mixture
optionally
treated with an adhesion promoter; wherein the first adhesive layer is
formed on the surfaces of the glass beads and irregularly shaped glass
particles not
embedded in the thermoplastic glass bead release layer such that the glass
beads are
embedded to between about 30% to about 80% oftheir average diameter in the
first
adhesive layer,
wherein the adhesion of the first adhesive to the glass beads is stronger than
the adhesion of the thermoplastic release layer to the glass beads, wherein
the
aforesaid average count ofirregularly shaped glass particles is based on
irregularly
shaped glass particles having a cross-sectional diameter equal to or greater
than the
smallest cross-sectional diameter in the threefold range;
wherein the transfer articles comprise at least about 3% irregularly shaped
glass particles by average count per unit area ofthe transfer article based
upon the
total count ofthe glass beads plus the irregularly shaped glass particles per
unit area
ofthe transfer article;
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wherein the glass beads and irregularly shaped particles are positioned such
that upon removal ofthe transfer Garner from the transfer article the
coe~cient of
friction of a planer surface of the first adhesive layer having a continuous
layer of
glass beads and irregularly shaped glass particles partially embedded therein
is less
than about 0.3.
The invention further provides the above-described transfer article wherein
the first adhesive layer is transparent and is sufficiently thin to conform to
the
spherical surfaces of the glass beads.
The invention further provides the previously described transfer article
wherein, the optional graphic images) disposed thereon also function as the
optional substrate adhesive.
The transfer article which comprises about 3% to about 15% or about 5%
to about 15% or about 6% to about 12% irregularly shaped glass particles by
average count per unit area ofthe transfer article based on the average total
count
per unit area of the transfer article of the glass beads plus the irregularly
shaped
glass particles is also provided.
The transfer article wherein the first adhesive layer is discontinuous and
wherein the first adhesive layer is capable ofbonding to a substrate layer is
also
provided.
The invention further provides a method of making the transfer article of the
invention, the method comprising the steps of
(a) providing a transfer Garner, the transfer Garner comprising a
thermoplastic glass bead release layer bonded to a support layer;
(b) partially embedding a layer of a mixture of transparent glass beads and
irregularly shaped glass particles, the mixture optionally treated with an
adhesion
promoter such that the glass beads are embedded to between about 20% and about
70% of their average diameter in the thermoplastic glass bead release layer
and at
least some ofthe irregularly shaped glass particles are partially embedded in
the
release layer and some of the irregularly shaped glass particles are
optionally,
completely embedded in the release layer;
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/D
wherein the average cross-sectional diameter of the mixture of the glass
beads and the irregularly shaped glass particles, for at least 95% by weight
ofthe
mixture ranges from about 20 microns to about 180 microns;
wherein at least 95 % by weight of the total number of glass beads and
irregularly shaped glass particles fall within a threefold range such that the
smallest
and largest cross-sectional diameters di$'er by a factor of about 3 or less;
wherein the transfer article comprises at least about 3% irregularly shaped
glass particles by average count per unit area of the transfer article based
on the
average total count per unit area ofthe transfer article ofthe glass beads
plus the
irregularly shaped glass particles, wherein the aforesaid average count of
irregularly
shaped glass particles is based on irregularly shaped glass particles having a
cross-
sectional diameter equal to or greater than the smallest cross-sectional
diameter in
the threefold range;
wherein the glass beads and irregularly shaped glass particles have refractive
indexes of about 1.5 to about 1.6;
(c) bonding a layer of a first adhesive layer over the surfaces of the glass
beads and irregularly shaped glass particles not embedded in the thermoplastic
release layer;
wherein the adhesion of the first adhesive layer to the glass beads is
stronger
than the adhesion of the thermoplastic release layer to the glass beads;
wherein the glass beads and irregularly shaped particles are positioned such
that upon removal of the transfer carrier of the transfer article the
coefficient of
friction of a planer surface of the first adhesive layer having a continuous
layer of
the mixture of the glass beads and irregularly shaped glass particles
partially
embedded therein is less than about 0.3.
The method wherein the transfer article comprises at least about 3% to
about 15% or about 5% to about 15% or about 6% to about 12% irregularly
shaped glass particles by average count per unit area ofthe transfer article
based on
the average total count per unit area ofthe transfer article ofthe glass beads
plus
the irregularly shaped glass particles is also provided.
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The method which further comprises a step ofbonding a substrate to the
surface of the adhesive layer opposite the layer of embedded glass beads via a
substrate adhesive is also provided.
The method wherein the first adhesive layer is discontinuous and wherein
the first adhesive layer is bonded to a substrate on a side opposite the layer
of
embedded glass beads and irregularly shaped glass particles is also provided.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-section of a prior art glass bead coated sheeting wherein a
layer of high refractive index beads of equal diameter are depicted.
FIG. 2 is a cross-section of a comparative glass bead coated sheeting
wherein an abrasive layer of high refractive index beads of differing
diameters
intermixed with non-spherical irregularly shaped glass particles is provided.
FIG. 3 is a cross-section of one embodiment of a bead coated article of the
invention.
FIG. 3A is a cross-section of another embodiment of a bead coated article
of the invention having an optional reinforcing layer and an optional
substrate
adhesive layer bonded to a substrate.
FIG. 4 is a cross-section of another embodiment of the bead coated article
of the invention wherein optional continuous and discontinuous colored
polymeric
layers are illustrated.
FIG. 5 is a cross-section of another embodiment ofthe bead coated article
of the invention which has been embossed to provide a textured surface.
FIG. 6 is a cross-section of a transfer article of the invention.
FIG. 7 is a cross-section of another embodiment of the bead coated article
of the invention wherein the substrate layer is a fabric.
FIG. 7A is a cross-section of another embodiment ofthe bead coated article
of the invention wherein the substrate is a fabric and which also comprises a
substrate adhesive layer.
FIG. 8 is a cross-section of another embodiment of a transfer article of the
invention wherein an ink layer in the form of an image has been formed on the
glass
bead layer embedded in the temporary carrier and subsequently coated while the
ink
was wet with a substrate adhesive in the form of a powder.
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1~1.
FIG. 9 is a cross-section of another transfer article of the invention wherein
an optionally colored substrate adhesive in the form of an image has been
formed on
the glass beads embedded in the temporary Garner.
FIG. 10 is a cross-section of another embodiment of a transfer article of the
invention wherein a transparent colorless bead adhesive layer has been formed
on
the glass beads embedded in the temporary Garner.
FIG. 11 is a cross-section of another embodiment of a transfer article of the
invention wherein the transfer article of FIG. I O has been printed with an
ink layer
in the form of an image, followed by the formation of an adhesive layer over
the inli
layer.
FIG. 12 is a cross-section of another embodiment of a transfer article of the
invention wherein four ink layers have been printed on the transfer article of
FTG. 10 such that each ink layer has a different image.
FIG. 13 is another embodiment of the bead coated article of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Transfer Carrier an Process
The transfer coating method of the invention can be used to form the
transfer article ofthe invention from which can be formed the bead coated
article of
the invention. This novel method provides a bead coated article having a
unifoam
surprisingly smooth, exposed glass bead surface. The novel method surprisingly
positions irregularly shaped glass particles which are intermixed with the
glass beads
used according to the invention such that the irregularly shaped glass
particles do
not project to a substantial extent (preferably not at all) above the exposed
glass
bead surface where they would introduce abrasion ifthey were present in
substantial
numbers.
The transfer coating method of the invention employs a transfer carrier
which in its simplest form comprises a support layer and a thermoplastic
release
layer bonded thereto. The thermoplastic release layer ofthe transfer carrier
temporarily partially embeds a layer oflow refractive index glass beads. The
transfer carrier has low adhesion to the glass beads and to the adhesive layer
in
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which the opposite sides ofthe beads are partially embedded, so that the
transfer
Garner can be removed to expose the surface of the glass beads.
Support Layers
The support layer should be "dimensionally stable". In other words it
should not shrink, expand, phase change, etc. during the preparation of the
transfer
article. Useful support layers may be thermoplastic, non-thermoplastic or
thermosetting, for example. One skilled in the art would be able to select a
useful
support Iayer for the transfer article of the invention. If the support layer
is a
thermoplastic layer it should preferably have a melting point above that of
the
thermoplastic release layer ofthe transfer Garner. Useful support layers for
forming
the transfer carrier include but are not limited to those selected from the
group
consisting of paper and polymeric films such as biaxially oriented
polyethylene
terephthalate (PET), polypropylene, polymethylpentene and the like which
exhibit
good temperature stability and tensile so they can undergo processing
operations
such as bead coating, adhesive coating, drying, printing, and the like. Paper
and
PET are preferred support layers.
Thermoplastic Release Layers
Usefizl thermoplastic release layers for forming the transfer Garner include
but are not limited to those selected from the group consisting ofpolyolefins
such
as polyethylene, polypropylene, organic waxes, blends thereof, and the like.
Low to
medium density (about 0.910 to 0.940 g/cc density) polyethylene is preferred
because it has a melting point high enough to accommodate subsequent coating
and
drying operations which may be involved in preparing the transfer article, and
also
because it releases from a range of adhesive materials which may be used as
the
glass bead adhesive, in addition to the beads.
The thickness of the thermoplastic release layer is chosen according to the
bead diameter distribution to be coated. According to the transfer coating
method
ofthe invention the bead adhesive embedment becomes approximately the mirror
image of the transfer Garner embedment. For example, a glass bead which is
embedded to about 30% ofits diameter in the release layer ofthe transfer
carrier is
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typically embedded to about 70 % ofits diameter in the bead adhesive layer. To
maximize slipperiness and packing density of the bead layer it is desirable to
control
the embedment process so that the upper surface ofthe smaller beads and the
larger
beads in a given population end up at about the same level after the transfer
carrier
is removed.
In order to partially embed the glass beads and irregularly shaped glass
particles in the release layer, the release layer should preferably be in a
tacky state
(either inherently tacky and/or by heating).The glass beads and irregularly
shaped
glass particles may be partially embedded, for example, by coating a layer of
transparent glass beads having intermixed therewith irregularly shaped glass
particles on the thermoplastic release layer ofthe transfer earner followed by
one of
( 1 )-(3 ):( 1 ) heating the glass bead coated transfer carrier, (2) applying
pressure to
the glass bead coated transfer carrier (with, for example, a roller) or (3)
heating and
applying pressure to the glass bead coated transfer carrier.
For a given thermoplastic release layer, the bead embedment process is
controlled primarily by temperature, time ofheating and thickness ofthe
thermoplastic release layer. As the thermoplastic release layer is melted, the
smaller
beads in any given population will embed at a faster rate and to a greater
extent
than the larger beads because of surface wetting forces. The interface of the
thermoplastic release layer with the support Layer becomes an embedment
bounding
surface since the beads will sink until they are stopped by the dimensionally
stable
support layer. For this reason it is preferable that this interface be
relatively flat.
Irregularly shaped glass particles mixed with the glass beads will also become
at
least partially embedded in the thermoplastic release layer. Most will become
only
partially embedded. Small irregularly shaped glass particles may become
completely
embedded in the thermoplastic release Layer.
The thickness of the thermoplastic release layer should be chosen to prevent
encapsulation ofmost ofthe smaller diameter glass beads so that they will not
be
pulled away from the bead adhesive layer when the transfer carrier is removed.
On
the other hand, the thermoplastic release layer must be thick enough so that
the
larger beads in the bead Iayer are su~ciently embedded to prevent their loss
during
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rs
subsequent processing operations (such as coating with the bead adhesive
layer, for
example).
Preferably, the thiclmess of the thermoplastic release layer is selected to be
no less than about 70% of the diameter of the smallest bead falling within the
20 to
180 micron range nor more than about one fourth times the diameter of the
largest
bead falling within the 20 to 180 micron range to result in a corresponding
bead
adhesive embedment of about 30 to about 75 percent.
Low Refractive Iudex Glass Beads and Irre~ularl~ped Glass Particles
The glass beads useful in the present invention are typically manufactured
from economical low refractive index ordinary glass having a typical
refractive
index of about 1.50 to about 1.55. The glass beads are largely spherically
shaped.
The glass beads are typically made by grinding ordinary soda-lime glass or
boro-
silicate glass, typically from recycled sources such as from glazing and/or
glassware.
The grinding process yields a wide distribution of glass particle sizes. The
glass
particles are spheroidized by treating in a heated column to melt the glass
into
spherical droplets, which are subsequently cooled. Not all the beads are
perfect
spheres. Some are oblate, some are melted together and some contain small
bubbles.
The process of spheroidizing low refractive index glass results in retention
of some percentage, typically at least about 3% by average count, more
typically
about 3 to about 15 % by average count, even more typically about 5 to 15 % by
average count, and most typically about 6 to 12 % by average particle count of
irregularly shaped particles mixed with the beads based upon the total number
of
beads plus irregularly shaped particles of a defined minimum size using a
microscopic counting method described hereinafter. The retention of
irregularly
shaped glass particles is believed to be due to incomplete or non-uniform
flame
treatment or as a result of cross contamination from handling the input
materials in
the same approximate location. The terms "irregularly shaped glass particles "
and
"irregular glass particles" are used interchangeably herein. The term
'articles"
when discussing the present invention only, is meant to include both the
irregularly
shaped particles and the glass beads. The irregularly shaped glass particles
are
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i
typically randomly intermixed with the gl ~ beads. Typically the articles
ofthe
invention are prepared from the glass bead/ irregularly shaped glass particle
mixture
such that the irregularly shaped glass particles and beads are randomly
distributed
within the layers in which they are present. Typically the ratio ofirregularly
shaped
S glass particles in a give uncoated sample of beads remains approximately the
same
as the ratio in a transfer article or a bead-coated article prepared
therefrom.
Particle Sizing
The low refractive index glass beads and irregularly shaped glass particles
are typically sized via screen sieves to provide a useful distribution
ofparticle sizes.
Sieving through screens does not separate the irregularly shaped particles
from the
beads. Sieving is also used to characterized the size of the irregular
particles and
the beads. With sieving, a series of screens with controlled sized openings is
used
and the particles passing through the openings are assumed to be equal to or
smaller
than that opening size. For beads, this is true because the cross-sectional
diameter
of the sphere is almost always the same no matter how it is oriented to a
screen
opening. For irregularly shaped particles, which can vary in cross-sectional
diameter
depending on particle orientation, the sieve screen opening does not always
correspond to the maximum dimension of the particles. For purposes of defining
the size of the irregular particles I use the term "average cross-sectional
diameter".
"Average cross-sectional diameter" is defined as the average sieve opening
through
which the distribution of irregularly shaped particles will pass. Thus the
average
cross-sectional diameter ofthe irregularly shaped glass particles corresponds
to the
size of the glass beads and the same size range applies. It is desirable to
use as
broad a bead size range as possible to control economics and maximize the
packing
ofthe beads on the bead adhesive surface. However, some applications may
require
limiting the bead size range to provide a more uniform bead coated surface. A
useful range ofbead diameters is about 20 microns to about 180 microns
(typically
about 35 to about 140 microns, preferably about 35 to 90 microns, and most
preferably about 38 to about 75 microns). A small number (0 to 5 % by weight
based on the total number of beads plus irregularly shaped particles) of
smaller and
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larger beads and irregularly shaped glass particles falling outside the 20 to
180
micron range can be tolerated.
To calculate the "average cross-sectional diameter" of a mixture of glass
beads and irregularly shaped glass particles one would sieve a given weight of
particles such as, for example, a 100 gram sample through a stack of standard
sieves. The uppermost sieve would have the largest rated opening and the
lowest
sieve would have the smallest rated opening. For our purposed the average
cross-
sectional diameter can be effectively measure by using the following stack of
sieves.
U.S. Sieve Designation No. Nominal Opening (microns).
80 180
100 150
120 125
140 106
170 90
200 75
230 63
270 53
325 45
400 38
500 25
635 20
For calculation purposes the defined cross-sectional diameter for a fraction
of glass beads and irregularly shaped glass particles passing through a given
sieve
and being retained by the next smallest sieve is the average ofthe nominal
openings.
The two sieves are defined as a sieve pair. Thus, for example, if 20% of the
weight
of a given sample ofbeads and irregularly shaped particles passed through a 90
micron nominal opening, but did not pass through a 75 micron nominal opening,
the
cross-sectional diameter ofthe 20% fraction ofthat sieve pair would be
(90 + 75)/2 = 82.5 microns. The weighted cross-sectional diameter for that
fraction
would then be 82.5 x 0.20 = 16.5 microns. The average cross-sectional diameter
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1
for the whole distribution of glass beads a ~d irregular particles then
becomes the
sum of the weighted cross-sectional diameters of sieve pairs.
For a given mixture ofbeads and irregularly shaped glass particles having an
average cross-sectional diameter falling within the range of about 20 to about
180
microns, 95% ofthe beads and irregularly shaped particles have a range ofno
more
than about three times the smallest bead diameter, so that embedment in the
transfer
carrier's thermoplastic release layer can be managed to result in a
corresponding
embedment in the bead adhesive layer that is maximized to prevent loss of
beads
due to abrasion. It is preferred that the range ofbead and irregular particles
differ
by no more than a factor of about 2.8, preferably not greater than about 2.4.
(For
example, a 25 micron thermoplastic release layer can embed a 35 micron bead
about
70 percent which results in a 30 percent embedment in the bead adhesive layer.
A
98 micron bead (2.8 times 35) can have about 25% embedment in the release
layer,
which results in about 75% embedment in the bead adhesive layer.
Irregularly Shaped Particle Counting
To characterize how many irregularly shaped glass particles exist within a
given sample of uncoated glass beads and irregularly shaped glass particles
one
immerses several strips oftransparent pressure sensitive tape (for example, a
25 by
50 mm rectangular strip) in the bead sample to coat each with a mono-layer of
particles on the tape. Also, standard microscope slides coated with about 25
microns of a transparent pressure sensitive adhesive are useful alternatives
for
coating glass beads and irregularly shaped glass particles for
characterization
purposes. ~ne must first shake the glass bead sample in a container to make
sure
the beads and irregularly shaped particles are well mixed. The coated sample
is then
placed under an optical microscope and a magnification and field ofview chosen
so
that at least about 40 particles are visible. The particles are more visible
when
illuminated from below (in transmission). Partially visible particles on the
edge of
the field ofview are excluded from the count. All glass beads are not
completely
spherical, but have seen sufficient heat in the process to eliminate all
angular edges
and therefore their abrasiveness. These particles having all rounded surfaces
are
counted as spheres. If a particle has at least one edge, it is counted as an
irregularly
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shaped particle unless it is smaller in its largest dimension than the
smallest bead
diameter in the aforesaid threefold diameter range, in which case it is not
included in
the count. Irregular particles smaller in their largest dimension than the
smallest
bead in the threefold range are not considered abrasive since they would be
surrounded by larger spheres when coated on the bead coated articles of the
invention. In other words, to be counted as an irregularly shaped particle,
the
particle must have at least one dimension equal to or larger than the smallest
bead
diameter in the threefold range.
Based on the about 20 to about 180 micron size range of usefi~l particles in
the present invention the optimal field ofview range is about 100X-250X. A
picture is taken and the beads and the irregularly shaped particles are
counted. The
average count of irregularly shaped particles is expressed as a percentage and
is
defined as the average number ofirregular particles in at least five
representative
samples divided by the average total number of particles (glass beads plus
irregularly shaped particles) in those samples multiplied by 100.
To determine the irregular particle count on an article ofthe invention it is
best to put it in a form where the light source can be placed below the
sample. For
a transfer article, if one uses a thin paper or a transparent or translucent
film as the
support carrier, one can readily characterize how a given thermoplastic glass
bead
release layer will coat a given population of glass beads containing irregular
glass
particles. To characterize an article where the transfer Garner is removed,
the count
of irregular particles in the exposed surface can be characterized by
transferring it to
an intermediate substrate that is transparent or translucent to make the glass
particles easier to count.
The irregularly shaped glass particles and glass beads are positioned in the
bead coated article of the invention such that the coefficient of friction
limitation
discussed elsewhere herein is met. The irregularly shaped glass particles are
positioned in the bead adhesive layer such that the irregularly shaped
particles are
partially embedded in the bead adhesive layer and project up between the
beads. It
is preferred that any irregularly shaped particles that project up between the
beads
do not project above the upper surfaces of any beads or at least the
immediately
adjacent beads. However, some irregularly shaped particles may project above
the
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o~
upper surfaces ofthe beads as long as the coefficient offriction requirements
are
met. It is theorized that very minor amounts ofirregularly shaped particles
could
become completely embedded in the first adhesive layer due to their becoming
dislodged from the release layer during formation of the adhesive layer. This
is
acceptable because such an irregular particle would not be positioned to be
abrasive.
Adhesion Promoter
Typically, the glass beads, including the irregularly-shaped glass particles
intermixed therewith, are treated with an adhesion promoter such as those
selected
from the group consisting of silane coupling agent, titanate, organo-chromium
complex, and the Like, to maximize their adhesion to the bead adhesive Iayer,
especially with regard to moisture resistance. Preferably, the adhesion
promoter is a
silane such as aminosilane, glyoxide silane, or acrylsilane, so that the
resulting
treated glass surface still exhibits a hydrophilic character.
The treatment level for such adhesion promoters is on the order of 50 to
500 parts by weight adhesion promoter per million parts by weight beads plus
irregularly shaped particles. Beads having smaller diameters would typically
be
treated at higher levels because of their higher surface area. Treatment is
typically
accomplished by spray drying or wet mixing a dilute solution such as an
alcohol
solution (such as ethyl or isopropyl alcohol, for example) ofthe adhesion
promoter
with the beads and irregularly-shaped particles, followed by drying in a
tumbler or
auger-fed dryer to prevent the beads from sticking together. One skilled in
the art
would be able to determine how to best treat the glass beads and irregularly
shaped
glass particles with an adhesion promoter.
Bead Adhesive Layer
The bead adhesive layer (also referred to as the "first adhesive layer" or a
"bead bonding layer") is typically an organic polymeric material. It should
exhibit
good adhesion to the glass beads and irregularly shaped glass particles
themselves
or to the treated glass beads and treated irregularly shaped glass particles.
It is also
possible that an adhesion promoter for the glass beads could be added directly
to
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a1
the bead adhesive itself as long as it is compatible within the process window
for
disposing the bead adhesive on the bead surfaces. It is important that the
bead
adhesive has su~cient release from the thermoplastic release layer of the
transfer
carrier to allow removal of the transfer carrier from the beads which are
embedded
on one side in the thermoplastic release layer and on the other side in the
bead
adhesive layer.
Useful bead adhesives include, but are not limited to those selected from the
group consisting of polyurethanes, polyesters, acrylic and methacrylic acid
ester
polymers and copolymers, epoxies, polyvinyl chloride polymers and copolymers,
polyvinyl acetate polymers and copolymers, polyamide polymers and copolymers,
fluorine containing polymers and copolymers, silicone containing copolymers,
elastomers, such as neoprene, acrylonitrile butadiene copolymers, and
compatible
blends thereof.
The bead adhesive layer can be formed, for example, out of solution,
aqueous dispersion, or 100% solids coating such as via hot melt or extrusion.
Preferred bead adhesives are the aliphatic polyurethane aqueous dispersions
and
blends thereof with aqueous acrylic polymers and copolymers, thermoplastic
polyamides and copolymers and vinyl plastisols and organosols. Most preferred
bead adhesives are the aqueous aliphatic polyurethane dispersions because
oftheir
excellent solvent resistance, resistance to weathering, and the ease with
which they
may be cleaned.
The bead adhesive layer may be transparent, translucent, or opaque. It may
be colored or colorless. The bead adhesive layer may, for example, be clear
and
colorless or pigmented with opaque, transparent, or translucent dyes and/or
pigments.
If retroreflective performance is desired in at least a portion of the surface
layer of the bead coated article of the invention, such that a reflecting
layer (such as
a thin metallic layer such as an aluminum flake ink layer, for example) is
coated on
the buried (non-exposed) side ofthe glass beads, it is preferred that the bead
adhesive layer be transparent and thin such that it maintains the contours
ofthe
glass beads, so that it can also function as a spacing layer to focus the
incident light
on the reflecting layer placed below it.
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aar
The bead adhesive layer is typically formed on the transfer carrier after the
beads and irregularly shaped particles have been partially embedded in the
release
layer of the transfer Garner. The bead adhesive is typically coated over the
partially
embedded glass beads and irregularly shaped glass particles by a direct
coating
process but could also be provided over the beads via thermal lamination
either
from a separate carrier or by first forming the bead adhesive layer on a
separate
substrate from which it is subsequently transferred to cover the beads and the
irregularly shaped glass particles.
Substrate Layers __,
The bead coated articles and transfer articles ofthe invention can optionally
comprise one or more substrate layer(s). Examples of suitable substrate layers
include but are not limited to those selected from the group consisting of
fabrics
(including synthetics, non-synthetics, woven and non-woven such as nylon,
polyester, etc.), polymer coated fabrics such as vinyl coated fabrics,
polyurethane
coated fabrics, etc.; leather; metal; paint coated metal; paper; polymeric
films or
sheets such as polyethylene terephthalate, acrylics, polycarbonate,
polyurethane,
elastomers such as natural and synthetic rubber, and the like.
The substrates may, for example, be in the foam of a clothing article;
automobile, marine, or other vehicle seat coverings; automobile, marine, or
other
vehicle bodies; orthopedic devices; etc.
In the transfer and bead coated articles of the invention, the glass
bead/irregular particle layer is typically continuous although it may be
discontinuous. Tlie bead adhesive layer is typically continuous although it
may be
discontinuous. The substrate adhesive, when present, may be continuous or
discontinuous. Typically, the substrate Layer, when present, is continuous,
although
it may be discontinuous. In the bead coated articles of the invention all
layers can
optionally be continuous or discontinuous.
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Graphic Layer dons
According to the present invention the glass bead adhesive can optionally
also perform the function of acting as the adhesive for a desired substrate
and/or
further comprise pigments) such that it also has a graphic function.
The adhesive layer, when selected to function also as a substrate adhesive,
may be, for example, pigmented and provided in the form of an image, such as,
for
example, by screen printing the adhesive in the form of a graphic for transfer
to a
separate substrate. However, the bead adhesive layer, in some instances, is
preferably colorless and transparent so that it can allow transmission of
color from
either a substrate, separate graphic layers (discontinuous colored polymeric
layers)
placed below it, or from a separate substrate adhesive that is optionally
colored and
optionally printed in the form of a graphic image (a discontinuous layer).
Typically, if a graphic image is desired it is provided separately on the
surface of the transparent bead adhesive opposite the glass bead surface by at
least
one colored polymeric layer.
The optional colored polymeric layer may, for example, comprise an ink.
Examples of suitable inks for use in the present invention include but are not
limited
to those selected form the group consisting of pigmented vinyl polymers and
vinyl
copolymers, acrylic and methacrylic copolymers, urethane polymers and
copolymers, copolymers of ethylene with acrylic acid, methacrylic acid and
their
metallic salts, and blends thereof. The colored polymeric layer which can be
an ink
can be printed via a range of methods including, but not limited to screen
printing,
flexographic printing, offset printing, lithography, transfer
electrophotography,
transfer foil, and direct or transfer xerography. The colored polymeric layer
may be
transparent, opaque, or translucent.
If retroreflective performance is desired, the colored polymeric layer or
multiple colored polymeric layers should be thin enough to maintain the
contour of
the beaded surface. The last underlying layer should be a reflecting layer
such as a
polymeric layer containing nascent reflecting particles such as aluminum flake
or a
metallic layer such as vapor deposited aluminum. The resultant graphic image
could be a combination of individual retroreflective and non-retroreflective
images
when opaque colored polymeric layers are printed in some areas and reflecting
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ay
colored polymeric layers are printed in other areas. The graphic could
encompass a
broad range of color, especially if a 4-color graphic process is employed.
A colored polymeric layers) may be included in the articles of the invention
by a number of procedures. For example, a transfer carrier can have a layer of
glass
beads and particles embedded in the release Layer thereof; following which the
bead
embedded surface ofthe release layer is coated with a transparent layer ofbead
adhesive. This bead and adhesive coated transfer Garner can function as a
casting
Liner by coating, for example, a continuous colored plasticized vinyl layer
over the
bead adhesive layer and wet laminating a woven or non-woven fabric thereover.
Another method involves providing graphic layers (discontinuous colored
polymeric layers, for example) on the bead adhesive layer prior to casting a
continuous colored plasticized vinyl layer to approximate the image of
leather, for
example.
Optional Adhesiv L~er~)
The bead coated article and transfer article of the invention may each
optionally further comprise one or more adhesive layers in addition to the
bead
adhesive layer. A substrate adhesive layer, for example, may optionally be
included
in the article in order to provide a means for bonding the bead adhesive layer
or the
layers) of material optionally bonded to the bead adhesive layers to a
substrate.
These optional adhesive layers) may be optionally present when, for example,
the
bead adhesive layer cannot function also as an adhesive for a desired
substrate. A
substrate adhesive layer (as well as any other optional adhesive layers) may
comprise the same general types ofpolymeric materials used for the bead
adhesive
layer and may be applied following the same general procedures. However, each
adhesive layer used must be selected such that it will adhere the desired
layers
together. For example, a substrate adhesive layer must be selected such that
it can
adhere to an intended substrate as well as to the other layer to which it is
bonded.
ReinfQr~ing Layers)
Optional Layers may be included in the bead coated article and transfer
article of the invention to, for example, enhance the ability to separate the
transfer
carrier from the glass bead layer. Such an optional layer which in such an
article can
CA 02234652 2005-04-27
60557-5793
function as a reinforcing layer would typically be positioned in between the
glass
bead adhesive layer and a substrate adhesive layer. Examples of useful
reinforcing
layers would include additional substrate layer(s), for example.
A glass bead coated and adhesive coated ~ansfer carrier could be coated
5 with a fabric adhesive such as a polyester, or a polyamide, followed by
lamination to
a wovm fabric or to a moisture transmiidng membrane, to function as a slippery
liner for clothing, for example.
Embossinn
10 The articles of the invention may optionally be embossed. The embossing
procedure would typically involve subjecting the article, bonded to an
embossable
substrate, and with the transfer carrier removed, to heat and pressure such as
by a
heated patterned roller assembly or a patterned heated platen press. For
embossed
articles it is preferable that the first adhesive layer not be melted during
the
15 embossing operation, to preserve the bead embedment level, while at the
same time
flexible enough to be deformed without cracking. Another method of embossing
would be to thermally laminate the transfer article to an irregular substrate
such as,
for example a coarse fabric such that a$~ the transfer carrier is removed,
that the
surface. is conformed to the imeguiar layer below 'rt.
20 The present invention wt~l be better understood by referring to Figures 1-
13.
FIG. 1 is an illustration of a cross-section of a prior art bead coated
article
20 wherein a single layer of presumably monod>spesse glass, hard plastic or
sod
plastic beads 21 have bem coated via a direct coating method on a dexi'ble
substrate
23 ~ to that of Ueda et al., U.S. Patent No. 4,849,265. The beads are not
25 intermixed with irregularly shaped particles. Article 20 includes a layer
of glass
beads 21 which have bem electrostatically sprayed on the surface of an
adhesive
layer 22 while it was in a tacky state. The adhesive layer 22 is disposed on a
flexible substrate layer 23. A pressure-sensitive adhesive layer 24 is
disposed on a
side of the flexible substrate layer 23 opposite the side which is bonded to
adhesive
layer 22. The pressure-sensitive adhesive layer 24 is protected by a removable
release liner 25. The article 20 is suitable for lamination to another
substrate (not
shown).
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FIG. 2 is an illustration ofa comps ative bead coated article 30 produced by
a process similar to that disclosed in Ueda et al., U. S. Patent No. 4, 849,
265 except
that low refractive index glass beads intermixed with irregularly shaped
particles are
substituted for the beads of Ueda et al. A layer of a non-monodisperse glass
bead
31 distribution containing irregularly-shaped glass particles 36 such as those
obtained from spheroidized ordinary glass has been provided via spraying on an
adhesive layer 32 while in a tacky state. Adhesive layer 32 is disposed on
flexible
substrate 33 having a pressure-sensitive adhesive layer 34 formed on a side of
the
flexible substrate 33 opposite adhesive layer 32. The pressure-sensitive
adhesive
layer 34 is protected by a release liner 35. The comparative article 30 has an
abrasive surface due to the uneven surface provided by the broad distribution
of
glass beads 31 and the abrasive irregularly-shaped glass particles 36, a
substantial
number ofwhich project above the plane ofthe glass bead 31 surface.
FIG. 3 is an illustration of embodiment of the bead coated article 5 of the
invention having a layer of glass beads 1 of low refractive index and broad
size
range embedded in roughly a one-half state in bead adhesive layer 3. The bead
adhesive layer 3 is disposed on a substrate 4. The irregularly shaped glass
particles 2
are partially embedded in adhesive layer 3. The irregularly-shaped glass
particles 2
that project up between glass beads 1 do not project suffciently above the
upper
surface of the glass beads 1 that they introduce tactile abrasiveness. The
upper
surface of article 5 is free of exposed irregularly-shaped glass particles 2,
and each
bead 1 upper surface is at about the same level such that the surface does not
feel
abrasive.
FIG. 3A is an illustration of a cross-section of another embodiment of a
bead coated article 5a of the invention which is identical to the article 5 of
FIG. 3
except that an optional reinforcing layer 6 (such as a thermoplastic film
layer) is
disposed on adhesive layer 3 on a side opposite the layer ofglass beads 1. In
addition, an optional substrate adhesive layer 7 is disposed on a side of
reinforcing
layer 6 opposite bead adhesive layer 3. Optional substrate adhesive layer 7 is
bonded on a side opposite reinforcing layer 6 to substrate 4.
FIG. 4 is an illustration of a cross-section of another embodiment of a bead-
coated article 10 of the invention wherein a layer of low refractive index
glass beads
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11 of a broad size distribution is embedded in roughly a one-half state in a
transparent bead adhesive layer 13 which conforms to the rounded shapes ofthe
glass beads 11. Irregularly-shaped glass particles 12 are partially embedded
in
transparent adhesive layer 13 and do not project above the upper plane ofthe
bead
11 surfaces. The upper surfaces of all the glass beads 11 are at about the
same level
regardless of size. In this particular embodiment the bead adhesive layer 13
is
transparent so it can transmit buried graphic images. An ink image
(discontinuous
colored polymeric layer) 14 is attached to adhesive layer 13 on a side of
adhesive
layer 13 opposite that which has the glass beads 11 embedded therein. An
optional
continuous colored polymeric layer 15 has been disposed on the entire surface
over
the ink image 14 and the portions of the adhesive layer 13 not covered by the
ink
image 14. The optional colored layer 15 is adhered to substrate 17 via
substrate
adhesive layer 16.
FIG. 5 is an illustration of a cross-section of another embodiment of a bead
coated article 40 of the invention wherein low refractive index glass beads 41
are
embedded in roughly a one-half state in adhesive layer 43. Irregularly-shaped
glass
particles 42 are partially embedded in adhesive layer 43 and do not project
above
the upper surface ofthe beads 41. Substrate adhesive layer 44 is bonded to
adhesive layer 43 on a side of adhesive layer 43 opposite that in which the
glass
beads 41 are embedded. Flexible and embossable substrate 45 is bonded to
substrate adhesive layer 44 on a side of substrate adhesive layer 44 opposite
that
which is bonded to adhesive layer 43. The surface of the article 40 having the
exposed beads 41 is textured due to post embossing ofthe composite structure.
Even though the surface is textured via embossing, the upper exposed surfaces
of
adjacent glass beads 41 are at about the same level.
FIG. 6 is an illustration of a cross-section of an embodiment of a transfer
article 50 ofthe invention, comprising a transfer Garner comprising temporary
support layer 55 bonded to thermoplastic release layer 56. A layer oflow
refractive
index glass beads 51 are temporarily embedded in roughly a one-half state in
. 30 thermoplastic release layer 56. Adhesive layer 53 is disposed on
thermoplastic
release layer 56 and over glass bead layer 51 on the side of the beads 51 not
embedded in thermoplastic release layer 56. Irregularly-shaped glass particles
52
CA 02234652 2005-04-27
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28
are distnbmed is random fashion such that some particles 52 are partially
embedded
in thermoplastic release layer 56 and adhesive layer 53. The irregularlyshaped
particles 52 which are partially embedded is both thermoplastic release layer
56 and
adhesive layer 53 are embedded such that any of such partially embedded
particles
remaining in adhesive layer 53 a$er removal of the transfer carrier do not
extend
above the upper exposed surfaces ofthe beads 51 partially embedded nn adhesive
layer 53 to cause an abrasive surface. Release liner 54 is positioned against
adhesive layer 53. The transfer article 50 may be used by removing release
liner 54
to expose adhesive layer 53. Adhesive layer 53 can then be attached to a
substrate
(not shown). Support layer 55 and the thermoplastic release layer 56 to which
it is
bonded can be removed to expose the upper surface of low refractive index
glass
beads 51. The irregularly-shaped glass particles 52 which are more deeply
embedded in thermoplastic release layer 56 than is adhesive layer 53 can be
removed from a surface position upon removal ofthe support layer 55 .and the
I S thermoplastic release layer, 56 .
FIG. 7 is an action of cross-section of a bead coated article 60 of the
invention camrprisiag a layer of low refractive index glass beads 61 embedded
in
roughly s one-half state in bead adhesive layer 63. The upper surface of
adjacent
glass beads 61 are at about the same level regardless ofbead 61 size. Bead
adhesive layer 63 functions also as a substrate adhesive in adhering the beads
61 to
fabric substrate 64. Irregularly shaped glass particles 62 are embedded in
adhesive
layer 63 such that they do not project sufficiently above the upper surface of
glass
beads 61 to cause tactile abrasiveness. Article 60 could have been foamed, for
example, by thermal lamination of the article 9 of FIG. 6 to fabric substrate
64 after
removal of release liner 54, foDowed by the,removal of layers 55 and 56.
FIG. 7A is a cross-section of a bead coated article 70 of the invention
comprising a layer of low refractive index glass beads 71 embedded in roughly
a
one-half state in adhesive layer 73 which conforms to the rounded surfaces of
the
glass beads 71. The upper surface of adjacent glass beads 71 are at about the
same
level regardless ofbead 71 size. Substrate adhesive layer 74 is bonded to the
side
of bead adhesive layer 73 opposite that ie which the glass beads 71 are
embedded.
Fabric substrate 75 is bonded to substrate adhesive layer 74. htegtilarly
shaped
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glass particles 72 are embedded in adhesiv~layer 73 such that they do not
project
sufficiently above the upper surface of glass beads 71 to cause tactile
abrasiveness.
Article 70 could have been formed, for example, by forming a substrate
adhesive 74
on article 100 of Fig. 10 on the side of the transparent adhesive layer 103
away
from the glass beads 101, followed by laminating to substrate 74, followed by
removal of layers 104 and 105.
FIG. 8 is an illustration of a cross-section of a transfer article 80 of the
invention comprising temporary support layer 85 bonded to thermoplastic
release
layer 86. A layer of low refractive index glass beads 81 are embedded in
roughly a
one-half state in thermoplastic release layer 86. An ink layer 83 has been
formed in
the shape of an image on portions of glass bead layer 81. Powdered substrate
adhesive layer 84 is adhered to ink layer 83 but not on sections of the bead
81 layer
not covered by discontinuous ink layer 83. Powdered substrate adhesive layer
84
could, for example, have been disposed on ink layer 83 while the ink was in a
wet
tacky state such that it adhered to ink layer 83, but did not adhere to
portions of the
glass bead layer 81 not covered by ink layer 83.
The transfer article 80 is useful for forming images on a portion of a
substrate surface (not shown) resulting in an image containing the low
refractive
index glass bead 81 surface of the invention. This can be done by applying the
transfer article 80 via heat and pressure su~cient to melt powdered substrate
adhesive layer 84 to a substrate (not shown), followed by removal of temporary
support layer 85 and thermoplastic release layer 86.
FIG. 9 is an illustration of a cross-section of a transfer article 90 of the
invention comprising a temporary support Garner 94 bonded to thermoplastic
release layer 95. A layer of low refractive index glass beads 91 are embedded
in
roughly a one-half state in thermoplastic release layer 95. Adhesive layer 93,
optionally colored, is disposed in the form of an image (in a discontinuous
layer) on
portions of the glass bead 91 surface not embedded in the thermoplastic
release
layer 95. Irregularly-shaped glass particles 92 are randomly distributed such
that
most particles are partially embedded in both the thermoplastic layer 95 and
in the
adhesive layer 93. The transfer article 90 is useful for forming images on a
portion
of a substrate surface (not shown) by adhering the article 90 to a substrate
(not
CA 02234652 1998-04-14
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3
shown) via adhesive Iayer 93, which also ff actions as a substrate adhesive,
followed
by removal oftemporary support earner 94 and thermoplastic release layer 95.
FIG. 10 is an illustration of a cross-section of a transfer article 100 of the
invention, comprising a temporary carrier support layer 104 bonded to a
thermoplastic release layer 105. A layer of low refractive index glass beads
101 are
embedded in roughly a one-half state in the thermoplastic release layer 105. A
thin,
transparent bead adhesive layer 103 is disposed on the surface ofthe glass
beads
101 not embedded in thermoplastic release layer 105, such that it conforms to
the
contours ofthe bead 101 surfaces. hregularly-shaped glass particles 106 are
randomly distributed, such that most are partially embedded both in
thermoplastic
release layer 105 and in transparent adhesive layer 103, and some are
partially
embedded in both layers 105 and 103. Transfer article 100 is potentially
useful as a
casting liner on which a substrate (not shown) is formed over and bonded to
bead
adhesive layer 103. Images could be optionally printed on article 100 over
adhesive
layer 103 prior to forming a substrate layer (not shown) thereover. For
example, an
ink image may be printed on bead adhesive layer 103, prior to providing a
substrate
layer (not shown) thereover. Thermoplastic release layer 105 and temporary
carrier
support layer 104 would be removed after forming ofthe substrate over the
adhesive layer 103 to expose the low refractive index glass bead 101 surface
ofthe
article 100 of the invention.
FIG. 11 is an illustration of a cross-section of a transfer article 110 of the
invention which comprises a temporary support layer 115 bonded to a
thermoplastic
release layer 116. A layer of low refractive index glass beads 111 is embedded
to
roughly a one-half state in thermoplastic release layer 116. A thin,
transparent
adhesive layer 112 is bonded to the surface of the glass beads 111 not
embedded in
the thermoplastic release layer 116, such that it conforms to the contours of
the
glass bead 111 surfaces. Optional ink layer 113 is disposed in the form of an
image
on a portion of adhesive layer 112. Substrate adhesive layer 114 is bonded to
a
surface of optional ink layer 113 opposite that which is bonded to adhesive
layer
112. Irregularly-shaped glass particles I 17 are randomly distributed in the
article
110 such that most are partially embedded in both the thermoplastic release
layer
116 and in the adhesive layer 112. Transfer article 110 can be used by
adhering
CA 02234652 2005-04-27
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31
substrate adhesive layer 114 to a substrate (not shown), followed by removal
of
temporary carrier support layer 115 and release layer 116. Ifthe optional ink
layer
113 contains, for example, nascent reflecting particles, a wide observation
angle
retroreflective image would be visrble to a viewer.
FIG.12 is an r'llustration of a cross-section of a transfer article 120 of the
invention which comprises temporary support layer 127 bonded to thermoplastic
release layer 128. A layer of low refractive index glass beads 121 are
embedded to
roughly a one-half state in thermoplastic release layer 128. A thin,
transparent bead
adhesive layer 122 is bonded to a surface of glass bead layer 121 not embedded
in
thermoplastic release layer 128, such that it conforms to the contour of the
glass
bead 121 surface. Irregularly-shaped glass particles I I7 are randomly
distnbuted
such that most are partially embedded in both the thermoplastic release layer
128
and in the adhesive layer 122. Ink layer 123 is bonded in the form of an image
on a
portion of adhesive layer 122. Ink layer 124 is bonded, in the form of an
image on a
different portion of adhesive layer 122. Ink layer 125 is bonded in the form
of an
image on a different portion of adhesive layer 122. Ink layer 126 is bonded in
the
form of an image such that it covers portions of ink layer 125, adhesive layer
122 ,
and ink layer 124. Substrate adhesive layer 129 is bonded on the em've surface
of
the combined ink layers.
Transfer article 120 would typically be attached to a substrate via adhesive
layer 129 followed by removal of the temporary ,support layer 127 and
thermoplastic release layer 128. I~ for example, the substrate adhesive layer
129
contained ahmmaum flake reflecting particles, and ink layer 123 was an opaque
black ink, ink layer 124 was a transparent magenta ink, ink layer 125 was a
transparent cyan ink, and ink layer 126 was a transparent yellow ink printed
via 4-
color pmcess, then the area of overlapped images of ink layers 126 and 124
would
additionally provide an orange color and the area of overlapped images of ink
layer
126 and ink layer 125 would provide a green color. Additionally, all the
colors
except the black would exh:'b'rt a wide observation angle retroreflectivity.
FIG.13 is an illustration of a cross-section of a bead coated article 130 of
the invention comprising an imaged (discontinuous) layer of low refractive
index
glass beads 13I embedded in a roughly one-half state in imaged (discontinuous)
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adhesive layer 133. A substrate adhesiv~er 134 is bonded to adhesive layer 133
on a side of adhesive layer 133 opposite that in which the glass beads 131 are
embedded to substrate layer 135. Irregularly-shaped glass particles 132 are
randomly embedded in imaged adhesive Iayer I33 such that they do not project
above the upper surface of glass bead image layer I3 I. Article 130 could be
made,
for example, by forming a discontinuous image of a substrate adhesive on
transfer
article 100 shown in Fig. 10, (not shown), followed by adhering the substrate
adhesive to a separate substrate, followed by removal oflayers 104 and 105.
Coefficient of Friction Measurement
"Coei~cient offriction" is defined as the ratio ofthe resisting force that
arises when a planer surface of one substance slides over an adjoining surface
of
another substance when acted upon by a perpendicular force.
To measure the coefficient of friction one must choose a reference surface.
I choose low density polyethylene as a reference surface because it has a non-
polar
surface with Iow glass adhesion and is also somewhat deformable, like the
skin.
Specifically, about a 125 micron thick film of 0.923 density polyethylene,
having a melt index of about 10, extruded at about 240 Deg. C, using resin
from
Quantum chemical, Designated NA 219-000 was used as a reference surface.
The "Standard Test Method for Static and Kinetic Coe$icients of Friction of
Plastic Film and Sheeting" which is described in the American Society of
Testing
Materials (ASTM) D-1894, was chosen as the method because it is an accepted
practice for distinguishing surface fiiction differences. To conduct the test
each
surface must be continuous and flat. Additionally, if the article of the
invention was
intended to be embossed, the coefficient of friction data that applies would
be taken
on the non-embossed planer sample.
The stated reference surface of low density polyethylene was heated at
about 150 Deg. C. in a forced air oven for about 30 seconds to melt the
surface and
provide a uniform high gloss. The film was then conditioned (at about 23 Deg.
C
and 50% relative humidity for 40 hours) and then attached via a 50 micron
layer of
pressure sensitive adhesive to a square, flat steel sled about 6 mm thick,
with sides
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33
of 63.5 mm, on which was previously bonded a 3.2 mm thick elastomeric foam of
about 0.25 g/cu. cm. density. The reference film was cut Smm longer in the
direction of slide pull to allow wrapping of the leading edge of the foam
covered
sled.
The sled was placed on a clean rectangular sample of at least 70 mm by 195
mm ofthe conditioned test surface (having the exposed beads) which was in turn
bonded to a level rectangular supporting base fitted in a universal tensile
testing
machine so that the sled could be pulled across the surface with a low
friction
parallel pulley/nylon filament system attached to a cafbrated force
transducer.
Weight was added, centered on the sled, to result in about 300g. total sled
weight.
(The referenced test method suggests a 200g sled, but a 300g sled was found to
provide more consistent data).
The sled was pulled at a rate of about 30 mm/min. across the test surface for
at least about 130 mmi. At least three points were collected while the sled
was
moving such that the first point was beyond the first maximum force measured
and
the remaining points were greater than about 25 mm apart on the beaded sample.
For example the first data point could be collected after the sled had moved
25 mm
followed by a second data point 25 mm beyond the first data point and a third
data
point 50 mm beyond the second data point. The recorded fictional force for
each
run was the average of the three data points. If the reference film of
polyethylene
on the sled was scratched during a run it was replaced with a glossy reference
surface sample. Five sample runs are collected for each beaded surface sample
and
the reported value of coe~cient of fiction was the grand average of the
fictional
force recorded for the five runs divided by the 300 g sled weight. The
standard
deviation is also typically reported and it is preferable that the standard
deviation be
less than 10% of the coefficient of fiction value (most preferable 5%). The
referenced test method provides for measurement and calculation of static and
dynamic (kinetic) coeficient of friction. I have chosen dynamic coeficient of
fiction to approximate the tactile feel of the surface, since the precision
was higher.
The examples herein, which provide an average coeficient of fiction value,
used
this method.
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:3~1
In order to determine the coefficient of friction for an article of the
invention
smaller than the above described 70 mm by 195 mm sample size one would
proportionately reduce the size and weight of the sled. For example, if the
largest
available test surface was 20 mm by 40 mm, one would choose a sled smaller
than
20 mm, i.e., a square sled, for example, of about 18 mm on a side weighted to
18/63.5 x 300g=85g. The data collection points could be compressed
proportionately so that on each sample three representative force measurements
could be made on a 40 mm length. The first data point could be collected, for
example after the sled had moved 40mm/195 mm x 25= about 5mm, followed by
the second data point 5mm later, followed by the third data point 10 mm later.
EXAMPLES
The invention will be further explained by the following illustrative examples
which are intended to be non-limiting. Unless otherwise indicated, all parts,
percentages, ratios etc., are by weight in the Examples and elsewhere herein.
EXAMPLE 1
A transfer carrier liner was made by extruding about a 25 micron thick
thermoplastic release layer of low density polyethylene resin from Quantum
Chemical, designated NA 219-000 and having a melt index of about 10, at about
240 Deg. C on a 96 micron biaxially oriented support layer ofheat stabilized
polyethylene terephthalate (PET) film and treated with an ultraviolet corona
while
the polyethylene was molten, to adhere the polyethylene to the polyester.
Ordinary
soda-lime glass beads primarily from recycled glazing obtained from Flex-O-
lite Inc.
from their Muscatine, lA plant were treated via spray drying with about 300
parts
per million A-I 100 amino functional triethoxy silane from OSi Specialties
lnc. The
silane was dispersed at about 10% solids in 95%/5% ethanol/water. The beads
were dried at about 90 degrees C for 30 minutes. The following size
distribution of
the treated beads and irregularly shaped glass particles as approximately
measured
by sieving were cascade coated on the above transfer carrier at about 105 Deg.
C
and subsequently heated at about 120 Deg. C for about 1.5 minutes to partially
embed the beads:
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60557-5793
Sieve Pair Nominal~tg** Wei %*
Ope
150-180 0.3
(some agglomerates of beads)
125-150 1.2
106-125 3.7
190-106 7.9
75-90 10.3
53-75 12.6
53-63 14.1
45-53 24.1
38-45 24.7
25-38 1.1
*Weight°~ of total bids and irregular particles
**in Miaons
The calculated average cxoss-secr~nal diameter of this population was about 58
microns. (The irregularly shaped glass particles were approximatelsr eQually
5 distributed throughout the bead sire population with an average coum of
about
10% based upon the total count of the beads and the irregularly shaped
particles.
95% by weight of the beads and irregulars fell within a threefold cross-
sectional
diameter range of about 38 miaons to about 115 microhs. The average coemt of
irregular particles was based on particles having at least one dimension equal
to or
10 greater than 38 microns. The larger beads and the agglomerated beads were
only
loosely held by the liner, such that mild surface abrasion could dislodge
thear. The
beads having diameters below about 100 microns were held su$iaeatly, so that a
subsequent processing operation resulted in less bead loss.
A bead adhesive was made according to the following formula:
15 16.6% Bayhydrol 121 Aqueous polycarbonate polyurethane dispersion from
Miles
Inc.
13.8% NeoTac''"'' R 9314 Aqueous polyester polyurethane dispersion from Zeneca
Resins
19.3% Distilled Water
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0.05% BYKTM 025 defoamer, believed to b a polyoxyethylene modified
polydimethyl siloxane, from BYK Chemie
0.05% TritonTM GR-7M di-2-ethylhexyl sodium sulfosuccinate surfactant from
Rohm and Haas
2.0% Stabilizer solution having:
3 parts of UvinolTM N-3039, a substituted acrylonitrile UV absorber from
BASF and
1 part TinuvinTM 123, a hindered amine light stabilizer from Ciba Geigy @
13.8% solids in diethylene glycol monobutyl ether.
5.2% solvent, diethylene glycol monobutyl ether
43.0% isopropyl alcohol
(The above percentages are based on the total weight ofthe bead adhesive.)
The above solution was made up in the given order of addition under mild
mixing with a low shear air mixer. Immediately prior to coating, 0.25 parts
per 100
parts solution of CX-100TM, a polyaziridine crosslinker from Zeneca Resins was
mixed in with an air mixer. The solution was coated onto the bead side ofthe
transfer carrier with a 12.7 cm diameter 60 Shore A durometer rubber squeeze
roll
against a 80 durometer back-up roller at a nip pressure of about 1.5 Kg/sq.
cm. and
having a contact width of 0.35 meters, with a line speed of about 4.5
meters/sec.
The coated transfer Garner was dried at 65 Deg. C for about one minute
followed
by 108 Deg. C for about 2 minutes. This resulted in an adhesive coated casting
liner of the invention as approximated in Fig. 10, wherein a thin layer of
adhesive is
conformed over the surface of the beads. The transfer article had an average
count
per unit area of about 9.9% of irregular particles equal to or larger in at
least one
dimension than 38 microns based on the total count ofthe beads plus the
irregular
shaped particles per unit area.
EXAMPLE 2
The resulting casting liner of Example 1 was coated in a knife coater at a
wet thickness of about 125 microns with the following substrate adhesive:
79.1% NeoRezTM R-9630, an aqueous carboxylated polyurethane dispersion from
Zeneca resins
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3~
20.6% diethylene glycol monobutyl ether
0.15% BYKTM 025 defoamer from BYK Chemie
0.15% TritonT"s GR 7M surfactant from Rohm and Haas
Immediately prior to coating, 0.50 parts (per 100 parts adhesive solution) of
CX-100TM, a polyaziridine crosslinker from Zeneca Resins was added in with an
air
mixer.
After coating, the adhesive was dried for 5 minutes at about 108 Deg. C.
The adhesive coated web was hot laminated to a smooth marine grade vinyl
fabric
seating material at about 130 Deg. C and cooled to room temperature, followed
by
removal of the transfer carrier. This resulted in a cross-section similar to
that
shown in Fig. 3. The resulting composite sheet had a low gloss surface and a
slippery skin tactility. The average dynamic coefficient of friction was found
to be
about 0.248 with a standard deviation of about 0.004 as measured by the
previously
defined method. Note that the polyethylene surfaced sled showed very slight
scratching after 3 runs and was replaced for the 4th and 5th runs. The
resulting
sheet, when wet with water, also exhibited low skin friction compared with the
uncoated vinyl fabric.
EXAMPLE 3
The resulting primed casting liner of Example 1 was screen printed with a
156 HD mesh polyester screen with an image ofthe following ink which also
functions as an adhesive for a vinyl substrate:
150 parts NeoRezTM R-9630, an aqueous carboxylated polyester polyurethane
dispersion from Zeneca resins
12 parts stabilizer solution consisting of
0.9 parts of TinuvinT"~ 1130, a benzotrialzole ultraviolet absorber from Ciba-
Geigy; 0.5 parts TinuvinTM123, a hindered amine light stabilizer;
0.2 parts Troysan PolyphaseTMAF-1, 3-iodo,2-propyl butyl carbonate
fungicide from Troy Chemical; and
10.4 parts diethylene glycol monobutyl ether.
1.5 parts SurfynolTM-104PA, 2,4,7,9, tetramethyl 5 decyn-4,7-diol a surfactant
from
Air Product & Chemical
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_3 g
0.3 parts SilwetTM L-7210, a modified polydimethylsiloxane copolymer flow
modifier from OSi specialties
2.3 parts BYKTM-025, a defoamer from BYK Chemie
40 parts AqualourTM 36B 14, a phthalocyanine blue pigment dispersion in
octylphenoxypolyethoxyethanol and tetramethyldecynediol and water from
Penn Color
30 parts Stapa HydroxalTM W. 16 N.L. aluminum pigment from Obron Atlantic
3.5 parts AerosilTM-200, a fumed silica flow modifier from Degussa.
The printed sheet was dried at about 105 Deg. C for 5 minutes. The
resulting screen printed image on the transfer Garner would approximately
correspond to the cross-section illustrated in Fig. 1 I with the exception
that layers
113 and 114 were combined into one layer.
The above imaged web was hot laminated for about 15 seconds in a 110
Deg. C platen press at a force of about 1.5 kg/sq. cm. onto a vinyl coated
automotive seating fabric, followed by cooling to room temperature and removal
of
the transfer Garner. Only the printed area transferred to the vinyl. The image
was
then reheated in the platen press for about 8 more seconds to emboss the beads
to
the same level as the vinyl surface. The resulting low gloss blue image, which
had a
cross-section which would correspond approximately to that exhibited by Fig.
13,
exhibited a low level of retroreflectivity when a light source was behind the
viewer,
which provided a decorative e$'ect.
EXAMPLE 4
The transfer Garner liner of Example 1 was bead coated in the manner of
Example 1 with a smaller and narrower fraction of low refractive index glass
bead
and irregularly shaped glass particle distribution with about 95% falling
within a 25-
75 micron cross-sectional diameter range with an average cross-sectional
diameter
of about 5 I microns. The average count of irregularly shaped particles was
about
7% per unit area by average total count per unit area ofbeads plus irregular
particles based on irregular particles larger in at least one dimension than
25
microns. In this case the beads were not pre-treated with a silane coupling
agent.
The resulting bead coated sheet was knife coated with about a 50 micron
orifice, as
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3g
measured above the top surface of the partially embedded beads, with the
following
adhesive:
100 parts Sx864B polyamide modified vinyl plastisol obtained from Plast-O-
Meric
SP Inc. of Sussex, WI.
4 parts ofA-1100 amino fimctional triethoxysilane from OSi Specialties Inc.
In this case, the silane was added to the plastisol by mixing it in with a low
shear air mixer immediately prior to coating. The adhesive coated bead coat
was
placed in a forced air oven set at about 125 Deg. C for about 20 seconds to
gel the
plastisol. At this point the sheet material corresponds approximately to Fig.
6,
except that the release liner is not present. The sheet material was then
thermally
laminated in a platen press to a smooth, light cotton muslin fabric, Roo-
lonTM#4.04
permanent press muslin from Pastad Mills Div. of Rockland Industries at about
170
Deg. C and about 3 Kg./sq. cm pressure for about 22 seconds to fuse the
plastisol
and bond it to the fabric. After cooling to room temperature, the transfer
Garner
was removed to reveal the bead coated surface. The adhesion of the beads to
the
modified fused plastisol adhesive, which was initially poor, continued to
build up
over 48 hours as the silane coupling agent reacted. The resulting non-
retroreflective bead coated fabric, which corresponds approximately to Fig. 7
had a
silky skin tactility and could function as an abrasion resistant lining for
clothing.
The same plastisol coated bead coat was thermally laminated to a coarse
woven polyester automotive fabric using the same conditions. After cooling and
removal of the transfer Garner, the surface of the bead coat was textured and
was
conformed to the woven irregular surface of the coarse fabric, which
corresponds
approximately to Fig. 5.
EXAMPLE 5
A bead coated and primed transfer carrier was made according to Example
1 using the glass bead and irregularly shaped glass particle distribution of
Example
4, except treated with the silane adhesion promoter described in Example 1. A
50
micron reinforcing film of SurlynTM 1705 Ionomer, a 5.5 melt flow index
thermoplastic copolymer of ethylene and methacrylic acid containing a zinc
ionic
crosslinking agent, from Dupont, was extruded at about 210 Deg. C. onto a 90
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-7 0
micron thick, biaxially oriented and heat stabilized polyester terephthalate
(PET)
carrier. It was subsequently air corona treated at 0.5 Joules/sq. cm, hot
laminated
on the SurlynTM film side to the bead coated and primed transfer carrier at
about
140 Deg. C and cooled to room temperature, followed by removal first, of the
90
micron PET and second, the transfer carrier, to result in an exposed glass
bead
surface on the SurlynTM reinforcing film. This construction corresponds
approximately to Fig. 3, wherein the SurlynTM film is the substrate.
A free radical solution polymerized acrylic terpolymer pressure sensitive
adhesive comprising by weight 70% isooctyl acrylate, 22.5% methyl acrylate and
7.5% acrylic acid, and having an intrinsic viscosity of about 0.6, and at
about 42%
solids in ethyl acetate solution, to which had been added by solids weight,
1.5%
azo-bis-isobutyronitrile, was knife coated onto a silicone release liner and
dried in a
forced air oven at about 90 Deg. C for 5 minutes, to result in about a 25
micron
thickness. The SurlynTM side of the above bead coated reinforcing film was air
corona treated at about 0.5 Joules/sq. cm and laminated to the pressure
sensitive
adhesive coated release liner. This embodiment corresponds approximately to
the
Fig. 3A cross-section wherein the release liner is the substrate. It contained
about
7.6 % by average count per unit area irregular particles based on the total
average
count per unit area of the beads plus the irregular particles having at least
one
dimension equal to or greater than 25 microns. Subsequently, the release liner
was
removed and the film laminated to a painted auto panel to function as a low
gloss
protective film for the painted surface. This would again correspond
approximately
to Fig. 3A, wherein the painted auto panel is the substrate. The coef$cient of
friction ofthis surface was measured as in Example 2 and found to be about
0.207
with a standard deviation of about 0.004. The polyethylene surfaced sled
showed
no sign of scratching after five runs.
COMPARATIVE EXAMPLE 6
The 50 micron SurlynTM film on PET carrier of Example 5 was direct
cascade coated with the same glass bead and irregular particle distribution of
Example 5 at about 135 Deg. C and then placed on a flat surface in a
convection
oven set at about 160 Deg. C and embossed at about 4 kg force with a 152 mm
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~1
wide steel roller. After cooling, the PET carrier was removed and the SurlynTM
side
corona treated and laminated to the pressure sensitive adhesive as in Example
5.
The resulting sheet corresponds approximately to Fig. 2 and had about 6.7 % by
average count per unit area irregular glass particles (equal to or greater
than 25
microns in at least one dimension) based on the average total count per unit
area of
beads plus irregular particles on the surface. The sheet exhibited an abrasive
tactility, similar to a fine emery cloth. This surface, when applied to a flat
automotive painted panel as in Example 5 had a coe~cient offriction as
measured
according to the described method of about 0.360, with a standard deviation of
about 0.014. Additionally, the polyethylene surfaced sled exhibited visible
surface
scratches after each run, requiring replacement before each measurement.
EXAMPLE 7
The transfer carrier of Example 1 was bead coated with the glass bead and
irregularly shaped glass particle distribution ofExample 5 and primed with the
bead
adhesive of Example 1, using the processes of Example 1. The resulting sheet
which contained about 7% by average count per unit area of irregular particles
(equal to or greater than 25 microns in at least one dimension) based on the
total
average count per unit area of the beads plus irregular particles, was then
knife
coated with the following substrate adhesive at about 100 microns wet
thickness
and gelled at 125 Deg. C for 20 seconds:
100 parts SX864B polyamide modified vinyl plastisol from Plast-O-Meric.
1.5 parts of BASF UvinolTM N-3039 a substituted acrylonitrile ultraviolet
light
absorber
0.5 parts of Ciba-Geigy TinuvinTM 123 a hindered amine light stabilizer.
The resulting bead and adhesive coated transfer Garner, was thermally
laminated at about 170 Deg. C to a printed, smooth marine grade vinyl fabric,
followed by cooling and removal of the transfer carrier. The resulting bead
coated
sheet, which corresponds approximately to the cross-section ofFig. 3, had a
coefficient of friction, using the described method, of about 0.213 with a
standard
deviation of about 0.009, without visible evidence of scratching of the
polyethylene
surfaced sled during all five runs.
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°~'Z
g:XA.MPLE 8
The bead coated and primed transfer Garner of Example 5 was screen
printed with a 230 mesh polyester screen using the ink of Example 3, except
that
the Obron aluminum pigment was left out. While the ink was still wet the sheet
was
dusted with a nylon/caprolactam copolymer powdered adhesive from Elf Atochem,
M-548-OSON. The sheet was subsequently dried at 80 Deg. C for 10 minutes and
the excess powder was blown offwith a compressed air nozzle. The powder only
adhered where the ink image was printed. The resulting transfer graphic
corresponds approximately to the cross-section ofFig. 8. The transfer graphic
was
positioned on a piece ofvelvet automotive grade polyester seating fabric in a
platen
press set at about 120 Deg. C and pressurized for about 15 seconds at about
1.5
Kg/sq. cm. It was then cooled to room temperature, whereupon the transfer
carrier
was removed, and heating repeated in the platen press for about 8 more
seconds.
The resulting low gloss blue image, which was embossed into the velvet fabric
did
not exhibit any retroreflective character, but exhibited a silky smooth
tactility and
had the appearance of being part of the fabric.
EXAMPLE 9
The bead coated and adhesive coated transfer carrier of Example 1 was
direct printed on the adhesive side opposite the embedded glass beads side in
a
Xeikon digital laser print engine with a multi-colored image, using the Xeikon
4
color polyester toner/developer process. The resulting imaged sheet was screen
printed with the plastisol adhesive described in Example 7, using a 230 mesh
polyester screen such that the screen printed image corresponded to the
outside
boundaries ofthe Xeikon printed ink image. The plastisol adhesive image was
gelled as in Example 7. The resulting imaged transfer graphic sheet
corresponds
approximately to the cross-section of Fig. 12. The image was applied to a
light tan
polyester fabric by heating in a platen press at about 3 Kg/sq. cm. pressure
and at
165 Deg. C for about 22 seconds. After cooling to room temperature the
transfer
carrier was removed and the transferred image was heated for an additional 8
CA 02234652 1998-04-14
WO 97/16754 PC'1'/fJS96/17336
''!3
seconds in the platen press. The resulting low gloss image did not exhibit any
retroreflection.
EXAMPLE 10
Example 9 was repeated except that the screen printed substrate adhesive
was modified with about 2.5 parts per hundred parts ofplastisol adhesive with
a
pearl mica pigment, AillairTM Silver Grey N WR II from EM Industries. In this
case
the resulting transferred image exhibited a low level retroreflectivity when a
light
source was behind the viewer, which enhanced the decorative nature ofthe
image.
The following detailed description and examples have been given for clarity
and understanding only. No unnecessary limitations are to be understood
therefrom. The invention is not limited to the exact details shown and
descn'bed,
for variations obvious to one skilled in the art will be included within the
invention
defined by the claims.
