U.S. patent application number 15/591928 was filed with the patent office on 2017-10-19 for method of making a self-adhesive laminate.
The applicant listed for this patent is Wilsonart LLC. Invention is credited to Wen-Feng LIU, Lutz H. REITZEL, Donald P. SCHAEFER, James W. Stone.
Application Number | 20170298255 15/591928 |
Document ID | / |
Family ID | 36570306 |
Filed Date | 2017-10-19 |
United States Patent
Application |
20170298255 |
Kind Code |
A1 |
LIU; Wen-Feng ; et
al. |
October 19, 2017 |
METHOD OF MAKING A SELF-ADHESIVE LAMINATE
Abstract
A decorative laminate includes a laminate substrate coated with
an adhesive layer. The adhesive layer is a layer of a physically
setting, solvent-free adhesive material including an acrylic
polymer. The adhesive layer is self-adhesive at room temperature.
The adhesive-coated laminate substrate has a peeling-off force of
at least 0.2 N/mm.sup.2, after application on a carrier. A method
for the production of the adhesive-coated laminate substrate, its
use as a coating material, and a composite of the adhesive-coated
laminate substrate and a carrier material are also provided.
Inventors: |
LIU; Wen-Feng; (Naperville,
IL) ; Stone; James W.; (Northbrook, IL) ;
SCHAEFER; Donald P.; (Ansbach, DE) ; REITZEL; Lutz
H.; (Gross-Zimmern, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Wilsonart LLC |
Temple |
TX |
US |
|
|
Family ID: |
36570306 |
Appl. No.: |
15/591928 |
Filed: |
May 10, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13690152 |
Nov 30, 2012 |
9650545 |
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15591928 |
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11272991 |
Nov 14, 2005 |
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13690152 |
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60652257 |
Feb 11, 2005 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 37/1284 20130101;
B32B 21/04 20130101; B44C 5/0469 20130101; Y10T 428/1438 20150115;
Y10T 428/1452 20150115; B44C 1/105 20130101; C09J 7/29 20180101;
C09J 7/20 20180101; Y10T 428/14 20150115; C09J 7/22 20180101; C09J
7/35 20180101; C09J 2301/208 20200801; C09J 7/38 20180101; C09J
2433/00 20130101; C09J 7/385 20180101; B32B 7/12 20130101 |
International
Class: |
C09J 7/02 20060101
C09J007/02; B32B 7/12 20060101 B32B007/12; B32B 21/04 20060101
B32B021/04; C09J 7/02 20060101 C09J007/02; B44C 1/10 20060101
B44C001/10; C09J 7/02 20060101 C09J007/02; C09J 7/02 20060101
C09J007/02; C09J 7/02 20060101 C09J007/02; B44C 5/04 20060101
B44C005/04; B32B 37/12 20060101 B32B037/12 |
Claims
1. A method of making a high pressure decorative laminate,
comprising the steps of: providing a hardened high pressure
decorative laminate substrate formed of a homogeneously closed
material having a density not less than about 1.35 grams per cubic
centimeter; positioning an adhesive layer adjacent to the hardened
high pressure decorative laminate substrate, the adhesive layer
including a physically setting, solvent-free terpolymer of vinyl
acetate-ethylene and acrylic; and positioning a release layer
adjacent to the adhesive layer.
2. The method of claim 1, wherein the step of providing the
hardened high pressure decorative laminate substrate comprises:
impregnating fibrous strips with a curable resin to form
impregnated fibrous strips; and pressing the impregnated strips in
the presence of heat, causing the curable resin to flow and
subsequently harden.
3. The method of claim 2, wherein the pressing step is performed at
a temperature of about 120.degree. C. to about 150.degree. C. and a
pressure of at least about 7 mPa.
4. The method of claim 3, further comprising the step of applying a
decorative layer to the fibrous steps.
5. The method of claim 2, wherein the curable resin comprises a
melamine resin.
6. The method of claim 2, wherein the pressing step is performed at
a temperature of about 140.degree. C. to about 200.degree. C.
7. The method of claim 1, wherein the hardened high pressure
decorative laminate substrate has a thickness of about 0.3 mm to
about 15 mm.
8. The method of claim 1, wherein the adhesive layer is free of
water and organic liquids.
9. A method of making a high pressure decorative laminate,
comprising the steps of: impregnating fibrous strips with a curable
resin to form impregnated fibrous strips; pressing the impregnated
fibrous strips in the presence of heat to form a hardened high
pressure decorative laminate substrate; positioning a self-adhesive
layer adjacent to the hardened high pressure decorative laminate
substrate, the self-adhesive layer being free of water and organic
liquids; and positioning a release layer adjacent to the
self-adhesive layer.
10. The method of claim 9, wherein the hardened high pressure
decorative laminate substrate has a density of not less than about
1.35 grams per cubic centimeter.
11. The method of claim 9, wherein the self-adhesive layer
comprises a solvent-free terpolymer of vinyl acetate-ethylene and
acrylic.
12. The method of claim 9, wherein the self-adhesive layer
comprises an elastomer, a plasticizer, and a hydrocarbon resin.
13. The method of claim 12, wherein the elastomer constitutes about
10% to about 70% by weight of the self-adhesive layer.
14. The method of claim 13, wherein the elastomer comprises a
solvent-free terpolymer of vinyl acetate-ethylene and acrylic.
15. The method of claim 12, wherein the plasticizer comprises a low
molecular weight polyisobutylene having a molecular weight of about
800 to about 5000 grams/mol.
16. The method of claim 9, further comprising the steps of:
applying the self-adhesive layer to the release layer to form an
adhesive-coated release layer; and overlaying the adhesive-coated
release layer on the hardened high pressure decorative laminate
substrate with the self-adhesive layer facing the hardened high
pressure decorative laminate substrate.
17. A method of claim 16, further comprising the steps of applying
about 3-70 N/cm.sup.2 pressure to the adhesive-coated release layer
to press the self-adhesive layer onto the high pressure decorative
laminate substrate.
18. The method of claim 17, further comprising the step of heating
at least one of the self-adhesive layer and the high pressure
decorative laminate substrate.
19. A method of making a high pressure decorative laminate,
comprising the steps of: impregnating fibrous strips with a curable
resin to form impregnated fibrous strips; pressing the impregnated
fibrous strips in the presence of heat to form a hardened
high-pressure decorative laminate substrate; positioning a
non-pressure sensitive adhesive layer adjacent to the laminate
substrate; positioning a self-adhesive layer adjacent to the
non-pressure sensitive adhesive layer, the self-adhesive layer
being free of water and organic liquids; and positioning a release
layer adjacent to the self-adhesive layer.
20. The method of claim 19, wherein the self-adhesive layer
comprises a physically setting, solvent-free terpolymer of vinyl
acetate-ethylene and acrylic.
21. The method of claim 19, wherein the impregnated fibrous strips
are pressed under a pressure of at least about 5 mPa.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/690,152, filed on 30 Nov. 2012, which in
turn is a continuation of U.S. patent application Ser. No.
11/272,991, filed on 14 Nov. 2005, which in turn claims priority
under 35 U.S.C. .sctn.119(e) to Provisional Patent Application
60/652,257, filed on 11 Feb. 2005. The disclosure of these related
patent applications are hereby incorporated by reference herein in
their entirety and made a part hereof, including but not limited to
those portions that specifically appear hereinafter.
FIELD OF THE INVENTION
[0002] This invention relates to a decorative laminate substrate
that is coated with a self-adhesive layer of an adhesive material
including an acrylic polymer. Furthermore, the invention concerns a
method for the production of such a laminate.
BACKGROUND OF THE INVENTION
[0003] Laminated sheets (otherwise referred to as "laminate
substrates") are generally used for decorative purposes in many
areas of daily life. They are used, for example, in interior
construction for the covering or lining of windows, stairs, and
floors, and in the coating of furniture, both in the private as
well as in the commercial sectors.
[0004] Laminated sheets often are made of cellulose sheets
impregnated with curable synthetic resins and pressed with heat
under high pressure. One or more sheets on one or two sheet sides
exhibit decorative colors or decorations. Such laminated sheets
(known as high pressure laminates or HPL) are sold, for example, by
Resopal GmbH (a Wilsonart International company), under the
tradename RESOPAL.RTM..
[0005] The application of the laminated sheets on a carrier
substrate such as chipboard, fireboard, or plywood used for wall,
floor or ceiling finishes or other objects, can be done with an
aqueous adhesive. Depending on the type of the adhesive, various
conditions must be precisely maintained, so as to obtain a coating
of good quality and stability. According to known application
methods, the laminated sheets and the carrier are typically joined
together after the application of the adhesive, immediately or
after a short waiting time. The joining together is done according
to the previous methods under a pressing pressure of 2 to 5 bar and
at a temperature of up to 120.degree. C.
[0006] Furthermore, the adhesive application is typically uniformly
distributed over the laminated sheet and/or carrier surface, so as
to avoid warp phenomena. This is particularly true for
water-containing adhesive systems, in which the application
quantity is to be kept as low as possible.
[0007] With a nonuniform adhesive application and an inexact
maintenance of the pressing pressure, pressing temperature, and/or
pressing time, unsatisfactory results can be obtained during the
cementing. Thus, for example, excessively high temperatures can
lead to warping and material damage. Low temperatures or pressures
often result, on the other hand, in an insufficient adhesion.
Depending on the adhesive system, the pressing pressure and the
pressing temperature typically must be maintained between a few
minutes and up to several hours. If necessary, one must wait
overnight to obtain a final curing.
[0008] Working with solvent-containing contact adhesives generally
requires adherence to work protection and accident prevention
regulations. Furthermore, the use of solvent-containing adhesives
is generally classified as problematic from a health and
environmental policy viewpoint. The use of dispersion adhesives on
a water basis, such as casein glue, frequently leads to the partial
swelling of the carrier surface, which is frequently the case, for
example, when using particleboard as the carrier material. As a
result, a slightly corrugated or nonuniformly plane surface is
obtained. Furthermore, the drying of water- or solvent-containing
adhesives may require several hours.
[0009] Reaction adhesive, such as epoxide, polyesters, or
polyurethane adhesives, are also of concern with respect to health
and require a precise knowledge and maintenance of the processing
conditions.
[0010] The previous adhesives and adhesive methods typically
require a high equipment outlay, such as, for example, for the use
of uniform and high pressing pressures and for the maintenance of
the temperature. Depending on the adhesive, the curing, e.g., until
a sufficient adhesive is attained, can require several hours.
[0011] The circumstances mentioned above often make the use and the
successful processing of laminated sheets relatively difficult,
particularly for the private sector or in the craftsman's sector.
There is a need for an improved, efficient, safe, and less
expensive decorative laminate panel.
SUMMARY OF THE INVENTION
[0012] A general object of this invention is to provide an improved
adhesive-coated laminate substrate, particularly for use as a
decorative or protective laminate covering for a material, such as
wood, metal or mineral boards.
[0013] A more specific objective of this invention is to overcome
one or more of the problems described above. In addition to the
needs of the commercial sector, the needs of the private user with
regard to a simple processing or application are considered and
met.
[0014] Another object of this invention is to provide a decorative
adhesive-coated laminate substrate, which adheres rapidly and
firmly on a carrier substrate surface, without having to accept the
long waiting times.
[0015] The rapid and firm adhesion of the laminate on the carrier
can be achieved without the use and precise maintenance of high
pressures or high temperatures during the application.
[0016] Another object of this invention is simplifying or
eliminating the handling and application of the adhesive on the
carrier. In particular, the difficulty of obtaining a uniform
application of the adhesive on the carrier is avoided by instead
uniformly applying the adhesive to the laminate substrate.
[0017] Furthermore, it is an object of this invention to provide a
decorative laminate substrate that can be cemented without the use
of water or solvents, and is as unobjectionable as possible from a
health viewpoint and with regard to safety aspects.
[0018] Finally, it is an object of this invention to provide a
decorative laminate substrate, which, after application on a
carrier, provides a uniform planar surface.
[0019] The general object of the invention can be attained, at
least in part, through an improved decorative laminate substrate
coated with an adhesive layer. The adhesive layer may include a
layer of a physically setting, solvent-free adhesive material
including an acrylic polymer. The adhesive layer is self-adhesive
at room temperature.
[0020] The invention further comprehends a laminate including a
laminate substrate, a non-pressure sensitive adhesive layer applied
to the laminate substrate, and a self-adhesive layer applied to the
non-pressure sensitive adhesive layer. The non-pressure sensitive
adhesive layer serves as a barrier layer (e.g. "primer") to prevent
penetration of the self-adhesive layer into the laminate substrate,
and to provide the laminate substrate with a primed surface. The
self-adhesive layer includes a layer of a physically setting,
solvent-free adhesive material comprising an acrylic polymer. The
self-adhesive layer is self-adhesive at room temperature, meaning
it does not require heat for activation, and may be manually
activated upon contact with a carrier with or without pressure, or
with light manual pressure.
[0021] The present invention also includes a method for the
production of the laminate of this invention.
[0022] Furthermore, a composite material of a carrier and the
adhesive-coated laminate substrate and the use of the
adhesive-coated laminate substrate for the coating of carriers are
provided.
[0023] A decorative laminate with an adhesive layer is made
available, which is characterized in that the adhesive layer is a
layer of a physically setting, solvent-free adhesive, which is
self-adhesive at room temperature, wherein the laminated sheet has
a peeling-off force of at least 0.2 N/mm.sup.2 after the
application on a carrier at room temperature. It is possible, in a
manner which was not readily predictable, to make available a
laminate, which quickly and firmly adheres on a carrier, without
having to accept long waiting times.
[0024] Furthermore, the following advantages are attained by this
invention. The application of the adhesive-coated laminate
substrate on the carrier can be done without the use of high
pressures and increased temperatures. A simple short pressing
pressure, for example, manually, on the adhesive-coated laminate
substrate is generally sufficient for immediate adhesion to the
carrier. In addition, the adhesive-coated laminate substrate
adheres stably on a carrier. Thus, one obtains, for example, a very
high peeling-off force of the adhesive-coated laminate substrate
from the carrier. Furthermore, a high peel resistance and a high
static shearing strength are attained. Also with a temperature load
of the composite of the adhesive-coated laminate substrate and
carrier over a longer time, the adhesion remains stable and no
peeling of the decorative adhesive-coated laminate substrate from
the carrier appears. The adhesion characteristics, such as the
peeling force, the shearing strength, and the peel resistance also
are essentially retained with a temperature load. The previously
mentioned characteristics are already attained with a small
application quantity or layer thickness of the adhesive so that it
can be used in a manner which saves material. Another advantage is
to be found in that the adhesive application need not be undertaken
by the end user himself. The reverse of the laminate substrate is
already provided with the adhesive and can be immediately
processed--that is, be applied on the carrier, without processing
conditions of the adhesive, a uniform application, etc., having to
be observed. The laminate substrate already provided with adhesive,
in accordance with the invention, can be stored over a relatively
long time. It is not necessary to apply the laminate substrate to
the carrier immediately after application of the adhesive, as is
typically the case with previous adhesive systems. The
adhesive-coated laminate substrate of this invention provides a
particularly uniform and planar surface after application on a
carrier. In addition, the use of solvents and dispersants during
the cementing of the plate, in accordance with the invention, can
be dispensed with, which is particularly advantageous with regard
to environmental and health aspects. Finally, the adhesive used, in
accordance with the invention, contains only not very volatile
plasticizers with a relatively low evaporation.
[0025] The previously mentioned advantages provide a relatively
simple and easy to install adhesive-coated laminate substrate for
the private user and the craftsman without mechanical equipment.
The processing can be undertaken directly on site, without machines
or special apparatuses having to be used for the processing. By the
simple and rapid possibility of the application, the
adhesive-coated laminate substrate in accordance with the invention
is suitable, in particular, also, for the home user, to upgrade and
cover furniture, door surfaces, walls, etc.
[0026] Other objects and advantages will be apparent to those
skilled in the art from the following detailed description taken in
conjunction with the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 schematically illustrates a process for preparing an
adhesive-coated laminate substrate of the invention.
[0028] FIG. 2 schematically illustrates an alternative process for
preparing an adhesive-coated substrate laminate of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The present invention provides a decorative laminate
substrate having a self-adhesive layer applied, either directly or
indirectly, to one side of the laminate substrate. In one
embodiment of this invention, the self-adhesive layer, at room
temperature, includes a physically applied, solvent-free adhesive
material including an acrylic polymer. The adhesive-coated laminate
substrate of this invention provides improved bond strength or
adhesion, temperature and humidity resistance, and adequate shear
or creep resistance when bonded to a carrier. The adhesive-coated
laminate substrate is relatively easily applied by the end user, as
compared to typical known adhesive systems.
[0030] In accordance with the invention, "laminate substrate"
includes materials such as, for example, glass fiber fabrics,
paper, wood, textiles, plastic films, paper base laminates,
laminated fabrics, laminated wood, which are produced by a buildup
(the so-called laminating) of paper or fabric strips or glass fiber
mats, soaked or coated with synthetic resins, such as epoxy,
melamine resins, thermoplastics, phenoplastics, urea-formaldehyde
resins, and by using pressure and heat. They are designated, in the
state of the art, as "laminates" also, and are used in diverse
embodiments, such as plates, round rods, tubes, long and
construction molded articles, for many different uses, such as
printed circuits, for aircraft, motor vehicle, boat construction,
weather-resistant covers, sports gear (for example, skiers) and
decorative purposes.
[0031] In one embodiment of this invention, the use of a
high-pressure laminate ("HPL") as the laminate substrate has proved
to be very particularly advantageous. The HPLs have layers of
fibrous strips, preferably, paper, impregnated with curable resins,
and optionally, one or more decorative layers, wherein the
decorative layers are provided with decorative colors and/or
patterns and preferably, are impregnated with resins on a melamine
basis. The strips are bonded together under heat and high pressure
of about 5 mPa or greater. In accordance with the invention, a
continuously produced laminate (CPL) can also be used as the
laminate substrate.
[0032] As will be appreciated by one skilled in the art following
the teachings herein provided, various and alternative types,
shapes, configurations of laminate substrates are available for use
in the laminate of this invention. Such alternatives and details
regarding the above materials can be found, for example, in the
current technical literature, for example, "Ullmann's Encyclopedia
of Industrial Chemistry," 4th Edition, Vol. 15, p. 326, and the
norms DIN EN 438, Part 1 to Part 6, ISO 4586-1 and ISO 4586-2, each
herein incorporated by reference in its entirety.
[0033] In one embodiment of this invention, the laminate substrate
is a decorative high-pressure laminate preferably produced by a
method in which fibrous strips are impregnated with at least a
curable resin and then are pressed by the simultaneous use of heat,
advantageously at a temperature in the range of about 120.degree.
C. to about 150.degree. C., and at a pressure of at least 7 mPa, so
that the resins initially flow and subsequently harden. A
homogeneously closed material with an increased density,
advantageously about 1.35 g/cm.sup.3, and the desired surface
characteristics is desirably obtained. Within the scope of this
method, discontinuous multi-stage presses are used.
[0034] In another embodiment of this invention, a laminate
substrate in which the fibrous strips are impregnated with
heat-curable resins and then are continuously pressed on
double-band presses at a high temperature, preferably, in the range
of about 140 to about 200.degree. C., has proved particularly
advantageous. Such a method is particularly useful in producing
continuously produced laminates (CPLs).
[0035] In another embodiment of this invention, a plastic laminate,
in particular, polyester laminates made of paper strips, which are
impregnated with at least one polyester resin, is used as a
laminate substrate. One or both laminate sides thereby
advantageously have a decorative paper, impregnated with polyester
resin. The production of these polyester laminates advantageously
takes place continuously.
[0036] The thickness of the laminate substrate of this invention
can be selected freely, in principle, according to the field of
application; it is generally in the range of 0.2 mm to 20 mm or 0.3
to 15 mm. More desirably, the thickness can also be in the range of
0.5 mm to 3.0 mm or in the range of 0.6 to 2.5 mm. In one
embodiment, the thickness 0.6 to 1.6 mm is particularly desirable
and 0.6 to 1.2 mm is even more desirable.
[0037] In one particularly preferred embodiment of this invention,
a physically setting, solvent-free adhesive material is used to
form a self-adhesive layer on at least one side of the laminate
substrate. As used herein, "solvent-free" refers to an applied
adhesive layer that contains no water and no organic liquids, which
act as solvents or dispersants. In one embodiment, the
self-adhesive layer is formed at least in part of an adhesive
material including an acrylic polymer or copolymer.
[0038] In one particularly preferred embodiment of this invention,
the adhesive includes a terpolymer of vinyl acetate-ethylene and
acrylic. An example of such a terpolymer is available from Air
Products and Chemicals, Inc., Allentown, Pa., and sold under the
tradename FLEXBOND 153. Other FLEXBOND adhesives, such as, for
example, FLEXBOND AF75 and FLEXBOND EAF60 are useful in forming
laminates of this invention.
[0039] In one embodiment of this invention, the self-adhesive layer
includes at least one elastomer, at least one not very volatile
plasticizer, and at least one hydrocarbon resin. Additional
component(s) of the adhesive layer can be a elastomeric components
selected from the natural rubbers, polyisobutylene rubber,
ethylene-propylene rubber (EPR), styrene-butadiene rubber,
ethylene-propylene-diene-terpolymer rubber (EPDM), butyl rubber,
ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid
copolymer, ethylene-(meth)acrylate copolymer,
ethylene-(meth)acrylic acid-(methy)acrylate terpolymer, and
acrylate rubbers. The elastomer can also be a block copolymer as
described below. The elastomeric component(s) can be combined with
the acrylic polymer, i.e. a polymer which includes an acrylic
and/or acrylate group, e.g. the vinyl acetate-ethylene-acrylic
terpolymer described above. Other elastomers may be combined with
the acrylic polymer.
[0040] In one preferred embodiment of this invention, an additional
elastomer is a high molecular weight polyisobutylene rubber with a
number-average molecular weight of about 300,000-3,500,000 g/mol,
desirably about 400,000-1,500,000 g/mol, and more desirably about
800,000 g/mol (according to GPC). The polyisobutylene rubber can be
copolymerized with one or more comonomers, which are selected from
styrene, ring-substituted styrenes, divinylbenzene, isoprene,
indene, 1,3-butadiene, cyclopentadiene. The fraction of isobutene
in the polyisobutylene rubber is desirably about 90%.
[0041] In one embodiment of this invention, the total weight
fraction of the elastomer is about 10 to about 70 wt %, relative to
the dry weight of the adhesive, and preferably about 30 to about 60
wt %. Of this amount, the acrylic polymer (e.g. the vinyl
acetate-ethylene-acrylic terpolymer) should constitute at least
about 10% by weight of the adhesive composition, and may constitute
up to about 70% by weight depending on whether or not other
elastomers are also present. The balance of the adhesive
composition includes about 15-40% by weight of the plasticizer,
about 15-30% by weight of the hydrocarbon resin, and about 0.01-2%
by weight antioxidant.
[0042] The plasticizer can be a low-molecular weight
polyisobutylene with a molecular weight of about 800 to about 5000
g/mol. The weight fraction of the low-molecular weight
polyisobutylene can be about 18 to about 25 wt %, relative to the
total weight of the adhesive.
[0043] In accordance with one embodiment of this invention,
isobutylene polymers which can be used in the adhesive can be
obtained from Bayer AG, under the tradenames BAYER BUTYL (a
copolymer of isobutylene and isoprene) and POLYSAR BUTYL XL (a
copolymer of isobutylene, isoprene, and divinylbenzene).
[0044] In accordance with one embodiment of this invention, block
copolymers can be used as the elastomer which have at least two end
blocks of a vinyl-aromatic monomer (block A) and at least one
middle block (block B), which contains either a conjugated diene or
is formed from an ethylene-butylene copolymer or an
ethylene-propylene copolymer. The configuration can be linear,
grafted, or star-shaped, depending on the method of production.
[0045] Typical block copolymers with the simplest conformation have
the structure polystyrene-polybutadiene-polystyrene (SBS) or
polystyrene-polyisoprene-polystyrene (SIS), or
polystyrene-polyethylene/polybutylene-polystyrene. A typical radial
or star polymer comprises one in which the B-block has three or
four branches (radial) or more branches (star).
[0046] The end blocks A of the copolymer are formed from one or
more vinyl-aromatic monomers, which are advantageously selected
from styrene, ring-alkylated styrenes, such as alpha-methylstyrene
and vinyltoluene, and polycyclic vinyl-aromatic compounds, such as
vinylnaphthalene. Styrene and alpha-methylstyrene are preferred.
Styrene is especially preferred. A block which is built as the end
block A, can also be present, once or several times, in the middle
of the polymer chain, in addition to being at the ends.
[0047] If the middle block B of the block copolymer contains a
conjugated diene, it can be a homopolymer of a conjugated diene, a
copolymer from several conjugated dienes, or a copolymer from a
conjugated diene and a vinyl-aromatic compound, such as styrene or
alpha-methylstyrene, as long as the conjugated diene predominates.
The conjugated diene is preferably selected from a compound with
4-8 carbon atoms, such as butadiene, isoprene,
2,3-dimethyl-1,3-butadiene and piperylene, wherein butadiene and
isoprene are preferred.
[0048] If block B contains a conjugated diene, it can be partially
or completely hydrogenated. In addition, the A-blocks can also be
partially or completely hydrogenated.
[0049] The average molecular weight of an A-block is about
5000-125,000 g/mol, and preferably about 6000-60,000 g/mol (weight
average according to GPC). The average molecular weight of a
B-block is about 10,000-300,000 g/mol and preferably about
30,000-150,000 g/mol (weight average according to GPC). The total
weight of the block copolymer is desirably about 25,000 to about
350,000 g/mol, more desirably about 35,000-300,000 g/mol (weight
average according to GPC). Advantageously, the fraction of the
A-block is about 5-65 wt %, and more desirably about 35-50 wt %,
relative to the block copolymer. Another advantageous range is
about 5-30 wt %.
[0050] Details of the production of the aforementioned block
copolymer can be found, for example, in the documents EP 0 537 115
A1 and U.S. Pat. Nos. 3,239,478; 3,427,269; 3,700,633; 3,753,936;
and 3,932,327, the disclosure of each being herein incorporated by
reference in its entirety.
[0051] The aforementioned polymers can be used individually or in
combination with one another.
[0052] When used as an additional thermoplastic elastomer, the
weight fraction of the block copolymer is desirably about 5-50 wt
%, and more desirably about 10-40 wt %, relative to the total
weight of the adhesive. A more desirable range of the weight
fraction of the block copolymer is about 12-25 wt %, and more
desirably about 15-20 wt %. Another advantageous range for some
applications is about 30-40 wt %.
[0053] Exemplary block copolymers which can be used within the
scope of one embodiment of this invention, without limitation, can
be obtained, under the tradenames KRATON G1650, G1651, G1652,
G1657, G4309 (linear styrene-ethylene/butylene-ethylene block
copolymers of different block lengths), KRATON RP-6906, KRATON
DX1122, AND KRATON D1118X. These polymers are available from Kraton
Polymers, LLC.
[0054] To build up the pronounced long-term tackiness, the
adhesive, in one advantageous embodiment, contains synthetic
plasticizers with a low volatility (evaporation loss or migration)
at high temperatures (greater than about 120.degree. C.).
[0055] The plasticizers contained in the adhesive are desirably
synthetic plasticizers with a high boiling point and vapor
pressure, which are not very volatile and exhibit an only slight
evaporation from the adhesive.
[0056] Plasticizers are advantageously selected from mineral oils,
paraffin oils, olefin oligomers, and polymers with lower molecular
weights. As oligomers, one can use, for example, polypropylenes,
polybutenes (e.g. the low molecular weight polyisobutylene
described above), hydrogenated polyisoprenes, hydrogenated
butadienes, etc., wherein the molecular weight is advantageously
about 350 to about 10,000 g/mol.
[0057] The weight fraction of plasticizers is desirably about 0-40
wt %, and more desirably about 15-40 wt %, or about 15-30 wt %,
relative to the total weight of the adhesive.
[0058] Furthermore, hydrocarbon resins can optionally be added to
the adhesive, in order to attain a pronounced surface tackiness.
The surface tackiness (tack) makes possible a pronounced tackiness
in connection with low pressing forces during the assembly.
[0059] A group of the hydrocarbon resins (tackifiers), contained in
the adhesive, desirably include natural and modified resins, such
as, for example, gum resin, wood resin, tallow oil resin,
distillate resin, and rosin, hydrogenated resin, dimerized resin,
and polymerized resin.
[0060] Likewise, glycerol and pentaerythritol esters of natural and
modified resins, such as the aforementioned, can be used.
[0061] Other resins which can be used in the adhesive as tackifiers
are polyterpene resins, hydrogenated polyterpene resins, copolymers
and terpolymers of natural terpenes, such as styrene/terpene,
alpha-methylstyrene/terpene, and vinyltoluene/terpene. Also usable
are phenol-modified terpene resins, which can be obtained, for
example, by the condensation of a terpene and a phenol. Finally,
aliphatic, cycloaliphatic, aromatic and aliphatic/aromatic resins
based on petroleum can also be used as the hydrocarbon resin. Other
resins which can be used in accordance with the invention and are
known to the specialist are mentioned in the document EP 0 537 15
A1, the disclosure of which is herein incorporated by reference in
its entirety.
[0062] The weight fraction of the hydrocarbon resin can be about
0-80 wt %, relative to the total weight of the adhesive, more
desirably about 10-50 wt %, and even more desirably about 15-30 wt
%.
[0063] In one embodiment of this invention, the self-adhesive layer
and/or adhesive material can, optionally, contain common
stabilizers, antioxidants, and other auxiliaries, fillers, and/or
additives, known and available to those skilled in the art.
Antioxidants can advantageously be selected from the hindered
phenols and multifunctional phenols, such as sulfur- and
phosphorous-containing phenols. An overview of such stabilizers and
additives is given in the documents U.S. Pat. No. 6,143,818, and EP
0 537 115 A1, the disclosures of which are each incorporated by
reference herein in their entirety. The weight fraction of
stabilizers is desirably about 0.1-2 wt %, relative to the total
weight of the adhesive, and preferably about 0.1-1 wt %.
[0064] The self-adhesive laminate of this invention desirably has a
high tackiness, a strong immediate adhesion (tack), and also a high
cohesion and good shear or creep resistance. As a result of the
latter characteristics, the applied adhesive layer or the applied
laminate can be loaded mechanically. Advantageously, in one
embodiment of this invention, the applied adhesives are also
resistant to water, weak acids, and alkalis. Using adhesive
materials that are free of water or other solvents or dispersants
means that with a carrier substrate having an absorbing capacity,
they do not produce any swelling of the material due to the liquid.
In one embodiment of this invention, the adhesives used are
swell-free.
[0065] In one embodiment of this invention, those previously
described adhesives are used, which have a solids content of about
100%, a density of about 1 g/cm.sup.3 (at 20.degree. C.), a
viscosity at 160.degree. C. of about 15,000-65,000 mPas, a
processing temperature of 150-190.degree. C., a softening point of
about 90-135.degree. C. (DIN 52011), a static shearing resistance
at room temperature of about 5-15 kg (based on DIN EN 1943), a
peeling-off resistance of about 35-65 N/25 mm (based on DIN EN
1939), and a shearing strength loss temperature (measurement
method, see examples below), of about 60.degree. C. to about
105.degree. C., and more desirably about 65.degree. C. to about
97.degree. C.
[0066] In a particularly preferred embodiment of this invention,
the adhesive layer applied on the laminated sheet is covered, for
protection, with a release layer, which preferably is made, for
example, of a siliconized paper or film. In this state, the sheet
can be stored for a long time, desirably up to 12 months, without
losing its adhesive characteristics or undergoing some appreciable
decline.
[0067] The application quantity, or add-on level, of the previously
described adhesive on the laminate substrate is generally about 80
to about 300 g/m.sup.2, desirably about 140 to about 240 g/m.sup.2,
and more desirably about 150 to about 200 g/m.sup.2. In one
embodiment of the invention, the add-on level of the adhesive layer
is from about 75 to about 150 g/m.sup.2.
[0068] The layer thickness of the self-adhesive layer on the
laminate substrate is generally about 0.05 to about 0.50 mm, or
about 0.08 to about 0.30 mm, more desirably about 0.14 to about
0.24 mm, and particularly about 0.15 to about 0.20 mm. In one
embodiment of the invention, the self-adhesive layer is about 0.175
mm thick. If both a self-adhesive layer and a non-pressure
sensitive adhesive layer are used, each layer may have a thickness
of about 0.125 mm. The adhesive layers can be applied using a
roller coater or other suitable coating device. Each adhesive layer
is desirably applied to the release layer or laminate substrate as
a water-based emulsion; however, the adhesive layer can be applied
using organic solvent-based emulsions or hot-melts. The adhesive
layer is desirably applied to the release paper first, and then
dried, although the adhesive layer can also be applied to the
laminate substrate first. Upon application of the adhesive
emulsion, the adhesive is dried, such as at 100.degree. C. for 5
minutes, to form the applied solvent-free adhesive layer.
[0069] The pressing time upon application of the adhesive-coated
laminate substrate is, in accordance with the invention, less than
5 seconds. Advantageously, a pressing time of 1 to 3 seconds is
sufficient for bringing about an adhesion to the carrier with the
mechanical characteristics mentioned in the following.
[0070] The necessary pressing pressure in the application of the
adhesive-coated laminate substrate on the carrier surface is, in
accordance with one embodiment of this invention, at most 2 bar.
Desirably the needed pressing pressure is from about 0.2-1 bar and
more desirably about 0.3-0.6 bar. In general, a light pressure,
manually, is sufficient, in order to attain a complete adhesion.
With larger surfaces, a uniform pressure using a roller is
advantageous.
[0071] The application of the adhesive-coated laminate substrate of
one embodiment of this invention is preferably carried out in the
temperature range of about 5.degree. C. to about 35.degree. C.
Advantageously, the adhesive-coated laminate substrate can be
applied on a carrier at room temperature.
[0072] In one embodiment of this invention, the peeling-off force,
which is needed to peel off the adhesive-coated laminate substrate
applied on a carrier from the carrier, is at least about 0.2
N/mm.sup.2. Desirably the peeling-off force is about 0.2 to about 2
N/mm.sup.3, and more desirably about 0.5 to about 1.5 N/mm.sup.2,
and even more desirably about 0.8 to about 1.2 N/mm.sup.2. These
values of the peeling-off force are desirably attained when the
adhesive-coated laminate substrate is applied at room temperature
with the aforementioned pressing pressures, or by means of a light
pressure, manually or with a roller. The peeling-off force is
determined according to the method described in the European norm
EN 311, herein incorporated by reference in its entirety.
[0073] Alternately, the peeling-off force can be increased in that
the pressing pressure is increased above the aforementioned value
ranges. This is, however, not necessary for the invention and can
be optionally carried out, if desired.
[0074] Likewise, the peeling-off force of the adhesive-coated
laminate substrate from the carrier can be increased in that the
laminate substrate and the adhesive layer are heated shortly before
or during the cementing on the carrier. This measure is not
necessary and merely optional. Furthermore, the peeling-off force
can be affected if the surface of the laminate substrate on which
the adhesive is applied is roughened with the usual grinding agents
before the application of the adhesive.
[0075] Finally, it can be advantageous but not necessary to
pretreat the surface of the laminated substrate on which the
adhesive is applied with the usual adhesion priming agents for
adhesives, namely adhesion-imparting, preliminary paints or
primers. Common adhesion priming agents include, for example,
ethylene-acrylamide copolymers, polymeric isocyanates, and reactive
silicon-organic compounds.
[0076] The adhesive-coated laminate substrate of one embodiment of
this invention is characterized in that up to a temperature load of
80.degree. C. over at least 2 hours, a peeling of the laminate
substrate from a carrier material, in particular, from a particle
board, does not appear. In particular, a peeling is not observed
with a composite of the laminate, in accordance with the invention,
and a carrier after at least a two-hour temperature load of about
50.degree. C. to about 70.degree. C. The adhesive-coated laminate
substrate has been tested by introducing a sample laminate
substrate applied on a carrier into a furnace at room temperature,
which is filled with ambient air. This means that the air in the
interior of the furnace has the same temperature and moisture
content as the ambient air. Exemplary conditions are a temperature
of about 20-23.degree. C. and a relative humidity of 60-65% at the
beginning of the test. Subsequently, the furnace is closed and
heated to 80.degree. C., and is maintained at this temperature for
at least 2 hours.
[0077] The adhesive-coated laminate substrate of this invention can
be applied on different types of carriers, wherein the type of
carrier is not particularly limited. Preferred carrier materials
are melamine-coated particle boards, carrier plates coated with
laminate, chip board, medium-density fibrous plates, hard fibrous
plates, plywood boards, veneer sheets, solid wood, honeycombs,
foams, metal plates, sheet metal, mineral carriers, natural and
synthetic rock, tiles, and gypsum plaster board.
[0078] This invention further contemplates and includes a composite
material, which comprises one of the previously mentioned carriers
and an adhesive-coated laminate substrate which adheres to the
carrier. The laminate substrate can advantageously be applied both
on liquid-absorbing (absorbent) carriers, such as uncoated particle
boards and uncoated wood, as well as on non-liquid-absorbing
(nonabsorbent) carriers, such as metals, ceramic, glass, coated
woods, coated particle boards etc.
[0079] The composite of one embodiment of this invention is
characterized by a uniform and planar surface on the sides of the
applied laminate substrate. Thus, the maximum height difference on
the sides of the decorative layer is about 0.05-0.5 mm, and more
desirably about 0.05-0.2 mm. The uniformity can easily be
determined, in actual practice, by visual inspection, such as by
the undistorted reflection of a light source (for example, neon
tube) on the surface of the laminate substrate applied on the
carrier.
[0080] The adhesive-coated laminate substrate applied, in
accordance with one embodiment of this invention, on a carrier
generally has a more uniform and more planar surface, as compared
to laminate substrates applied using conventional methods/adhesives
on carriers.
[0081] Particularly advantageous, this characteristic manifests
itself, if the adhesive-coated laminate substrate is applied on an
absorbent or liquid-absorbing carrier. In this case, the laminate
substrate forms a more uniform and more planar surface than a sheet
that was applied with a solvent- or dispersant-containing
adhesive.
[0082] In another aspect, the invention under consideration
concerns the use of the previously described adhesive-coated
laminate substrate for the coating of a carrier material which is
preferably selected from the previously mentioned carrier
materials. The used carrier can be both liquid-absorbing
(absorbent) and also non-liquid-absorbing.
[0083] Likewise, the invention concerns the use of the composite of
the carrier material and the adhesive-coated laminate substrate in
interior and outside construction, such as for the covering of
walls, ceilings, and doors, and for the production and covering of
furniture and pieces of furniture.
[0084] Due to the previously described adhesion characteristics of
the adhesive-coated laminate substrate on the carrier material,
especially on particle boards, and the peeling-off resistance with
a temperature load, the composite is also suitable for the
production of pieces of furniture which are temporarily exposed to
high temperatures, such as kitchen work plates.
[0085] The invention also provides a production method for a
decorative laminate substrate with a self-adhesive layer. The
method of one embodiment of this invention is characterized in that
an adhesive material is applied on a laminate substrate at a
temperature of 150-190.degree. C., advantageously on the reverse
side opposite from the decorative side or layer, and is
subsequently allowed to cool.
[0086] Advantageously, the adhesive is desirably applied on a
continuously advanced laminate with a stationary roller or nozzle.
The adhesive application rate on the laminate is desirably about 1
to 30 m/min.
[0087] The adhesive is preferably applied in a quantity of about 80
to about 300 g/m.sup.2 desirably about 140 to about 240 g/m.sup.2,
and more desirably about 150 to about 200 g/m.sup.2, on the
laminate substrate.
[0088] The applied adhesive is advantageously covered with a
release layer, which advantageously is made of a siliconized paper
or a siliconized film.
[0089] In another embodiment of this invention, the laminate
substrate has two different adhesive layers applied thereon. A
non-pressure sensitive adhesive layer is first applied to one side
of the laminate substrate and a self-adhesive layer is applied to
the non-pressure sensitive adhesive layer, and thereby indirectly
applied to the laminate substrate. The self-adhesive layer includes
a layer of a physically setting, solvent-free adhesive material
comprising an acrylic polymer. The self-adhesive layer is desirably
self-adhesive at room temperature. A release layer, such as a
release paper or film, is desirably applied over the self-adhesive
layer to maintain the adhesive properties or tackiness until
use.
[0090] The self-adhesive layer desirably includes a terpolymer of
vinyl acetate-ethylene and acrylic. The non-pressure sensitive
adhesive layer comprises an adhesive material having a glass
transition temperature of about 20.degree. C. or greater. The
non-pressure sensitive layer desirably functions as a barrier layer
or primer separating the self-adhesive layer from the laminate
substrate. The barrier provided by the non-pressure sensitive
adhesive desirably reduces or eliminates penetration of the
self-adhesive into the laminate substrate. In one embodiment of his
invention, the non-pressure sensitive adhesive is, for example,
polyvinyl acetate. The non-pressure sensitive adhesive layer may
also be an acrylic primer as described below.
[0091] In one embodiment of this invention, the non-pressure
sensitive adhesive layer has an add-on level of about 10 to about
30 g/m.sup.2, and the self-adhesive layer has an add-on level of
about 75 to about 100 g/m.sup.2. The non-pressure sensitive
adhesive is desirably applied to the laminate substrate and
subsequently at least partially cured or dried before the
self-adhesive layer is applied over the applied non-pressure
sensitive adhesive. The layer of non-pressure sensitive adhesive
desirably provides improved temperature resistance and extends the
shelf life of the laminate before the final use or application to
the carrier. Both the self-adhesive layer and the non-pressure
sensitive adhesive layer can be applied as, for example, a
water-based emulsion, a solvent-based emulsion, or a hot melt.
[0092] The adhesive-coated laminate substrate may be prepared by
the following method. First, a release layer is coated with a layer
of physically setting, solvent-free adhesive which includes an
acrylic polymer. This may be accomplished by initially coating the
release layer with an aqueous or other solvent-based acrylic
adhesive, suitably containing about 35-75% by weight, or about
45-65% by weight adhesive solids. The water or other solvent is
then removed by evaporation at about 30-150.degree. C., suitably
about 75-120.degree. C. for a time of 1-15 minutes, or about 3-8
minutes, sufficient to cause drying. The adhesive layer may have a
dry thickness of about 50-500 microns, or about 80-300 microns, and
a wet thickness perhaps twice as large.
[0093] A suitable release layer is a silicone-coated paper, Type
402-6010, available from Wausau Paper Co. of Rhinelander, Wis.
Various other plastic-coated papers and plastic films can also be
employed as release layers. The adhesive layer may be thermoplastic
or thermosetting, and is suitably thermoplastic. Suitable adhesive
polymers include without limitation acrylic polymers, copolymers
and terpolymers as described above.
[0094] Second, the adhesive can be applied to a surface of the
laminate substrate by overlaying the adhesive-coated release layer
on the laminate substrate with the adhesive side facing the
laminate substrate. If the laminate substrate is a cellulose-based
high pressure laminate, or another laminate having a relatively
smooth surface, it may be desirable not to sand the surface or
otherwise increase its roughness prior to applying the adhesive.
The solvent-free adhesive is relatively viscous or solid and will
not easily penetrate into the valleys and crevices which are
present in a rough surface. When the laminate substrate surface is
relatively smooth, the adhesive may establish contact over the
entire surface, resulting in better adhesion.
[0095] Alternatively, the surface of the laminate substrate may be
both sanded and primed before applying the adhesive. The sanding
creates a rough surface having valleys and crevices which are
filled by coating with a suitable primer. Suitable primers include
easy drying, solvent-based primers having polymer components which
are compatible with the adhesive to be applied. For instance, an
acrylic-based primer dries to form an acrylic-based smooth surface
which has excellent affinity to an acrylic-based adhesive layer.
One suitable polyolefin-based primer contains about 50% by weight
solids and is sold by Lord Chemlok under the trade name 459X. The
primer coating may have a dry thickness of about 10-50 microns, or
about 15-40 microns, and a wet thickness perhaps twice as large.
Once the primer is dried, the adhesive is applied to the primed
surface of the laminate substrate.
[0096] Third, pressure is applied to the release layer to press the
adhesive onto the surface of the laminate substrate. A suitable
pressure is between about 3-70 N/cm.sup.2, suitably about 10-50
N/cm.sup.2. Once the adhesive has been pressed onto the laminate
substrate, the release layer is manually peelable to expose the
adhesive. For instance, the release layer can be manually peeled
away and the adhesive layer can be used to bond the laminate
substrate to a wall, floor, counter top, or other surface.
[0097] FIG. 1 schematically illustrates an exemplary process 10
useful for coating the adhesive layer onto the laminate substrate.
An adhesive layer 12, combined with a release layer 14, are unwound
from a roll 16. The foregoing layers are brought together with
laminate substrate 18 in a nip defined by nip rolls 20 and 22, with
the adhesive layer 12 facing the surface 17 of laminate substrate
18. Typically, laminate substrate 18 is positioned so that the
surface 17 is its back surface, i.e. the surface used to bond
adhesive-coated laminate substrate 28 to a wall, floor or
object.
[0098] FIG. 2 schematically illustrates an alternative process 11
which is similar to process 10 except for the presence of heaters.
The adhesive layer 12 may be heated using an external infrared
heater 24 and/or an internal heater (not shown) inside roll 20,
before the adhesive layer 12 is applied to and pressed onto the
surface 17 of laminate substrate 18. Alternatively, or
additionally, the laminate substrate 18 may be heated using
infrared heater 26 before the adhesive layer 12 is applied. In
either case, the heating may result in a temperature of about
30-120.degree. C., suitably 50-80.degree. C., which is high enough
to soften the adhesive layer 12 and impart a better adhesive bond
to the laminate substrate 18. The release layer 14 can still be
peelably removed to allow bonding of adhesive-coated laminate
substrate 28 to an object.
[0099] Examples of embodiments of this invention are described
below, which, in no way, represent a limitation of the inventive
idea.
1. Production of an Adhesive-Coated Laminate Substrate
[0100] All data refer to the weight.
[0101] From a supply container heated to 180.degree. C., an
adhesive based on 25% SIS, 15% SBS, and 60% hydrocarbon resin (with
a content of 10% polybutene), was conducted onto a roller with a
width of 60 cm and heated to 180.degree. C. The thermoplastically
liquified adhesive was conveyed via the roller and applied onto an
HPL sheet, which was advanced with the roller at 15 m/min, wherein
the gap between the roller and the HPL sheet was 3 mm, and the
adhesive was applied in a quantity of 180 g/m.sup.2. A siliconized
paper was applied for protection to the adhesive layer that was
still warm. Subsequently, the HPL sheet coated with the adhesive
was allowed to cool.
2. Application of the Adhesive-Coated Laminate Substrate on a
Carrier Material
[0102] The above adhesive-coated laminate substrate was applied, at
room temperature, on a carrier. The laminate, whose adhesive layer
was covered with a siliconized release paper, is first aligned on
the carrier. Subsequently, the release paper was pulled away,
partially at an edge, preferably on the narrow edge, and the
adhesive-coated laminate substrate was pressed on the carrier at
the edge with the exposed adhesive layer. Then, the release paper
was drawn out, step by step, under the adhesive-coated laminate
substrate and the laminate substrate is pressed, manually, on the
carrier. Advantageously, the adhesive-coated laminate substrate can
be pressed uniformly on the carrier substrate with a hard rubber
roller. A subsequent processing of the edges can be done with the
usual doctors, files, cutters, and grinders.
3. Mechanical Characteristics of the Composite Material Peeling-Off
Resistance
[0103] Measurement values for the peeling-off resistance of a
self-adhesive HPL, in accordance with the invention, on various
substrates, are shown below.
[0104] The determination of the peeling-off resistance is made
according to EN 311. The pressing of the adhesive-coated laminate
substrate on the carrier is carried out by light pressing manually
or with a roller.
TABLE-US-00001 Peeling-off resistance Carrier material (N/mm.sup.2)
Melamine-faced chipboard 0.7-1.5 Wood materials (particle board,
0.7-1.5 plywood, multiplex, MDF), precoated with laminated sheets
(HPL + CPL) Uncoated wood materials (particle 0.5-1.0 board,
plywood, multiplex, MDF) Polystyrene foam 0.2-0.5 Gypsum particle
board 0.2-0.5 Expanded mica plates 0.2-0.5 Aluminum, aluminum
honeycombs 0.2-0.5
[0105] All measurement values given above are based on roughened
HPL sheets. A smooth HPL surface may result in somewhat higher peel
resistance than a roughened surface if the adhesive is applied to
the HPL surface in a dry state from a release layer, or somewhat
lower peel resistance if the adhesive is applied to the HPL surface
in a wet state.
Measurement of the Sheet Strength Loss Tempering
[0106] A laminate substrate with an adhesive layer according to one
embodiment of this invention was cut to a size of 25 mm in width
and 70 mm in length. The test piece was applied on a carrier in
such a way that there was an overlapping of the adhesive area in
the longitudinal direction of 25 mm. On the free, lower end of the
test piece, a weight of 500 g was affixed. Subsequently, the test
setup was introduced into a furnace that was preheated to
40.degree. C. and left there at 40.degree. C. for 30 min. Then, the
furnace was heated at a heating rate of 0.37.degree. C. per minute
until the test piece detached from the carrier.
[0107] Shear resistance loss temperatures between 60.degree. C. and
105.degree. C. were measured with adhesive-coated laminated sheets,
in accordance with the invention.
[0108] Further laminate samples (12.7 cm.times.20.3 cm) were
prepared using: 1) FLEXBOND 153 to form a self-adhesive layer; and
2) FLEXBOND 153 to form a self-adhesive layer and polyvinyl acetate
to form a non-pressure sensitive adhesive layer. The laminate
samples were applied to a chip board and/or melamine carrier and
subjected to testing. The adhesive layers were applied at about 5
mils (127 microns) and dried at 100.degree. C. for 5 minutes.
[0109] The samples demonstrated temperature resistance upon
application to a carrier by maintaining adhesion and laminate
integrity to beyond 80.degree. C. The samples were placed in an
oven at 60.degree. C. and the temperature was raised ten degrees
every two hours until delamination was observed.
[0110] The samples each further demonstrated a desirable long-term
shelf life by maintaining laminate integrity at 75.degree. C.
beyond 1.5 months.
[0111] The samples demonstrated humidity resistance by maintaining
laminate integrity for over 14 days at 65.degree. C. and a 95%
humidity level.
[0112] The samples further demonstrated desirable shear strength by
having a peeling-off force of over 0.2 N/mm.sup.2 (e.g., about 0.26
and 0.35 N/mm.sup.2, respectively). The determination of the
peeling-off resistance was accomplished according to EN 311. The
pressing on the substrate is carried out by light pressing manually
or with a roller.
[0113] The invention illustratively disclosed herein suitably may
be practiced in the absence of any element, part, step, component,
or ingredient which is not specifically disclosed herein.
[0114] While in the foregoing detailed description this invention
has been described in relation to certain preferred embodiments
thereof, and many details have been set forth for purposes of
illustration, it will be apparent to those skilled in the art that
the invention is susceptible to additional embodiments and that
certain of the details described herein can be varied considerably
without departing from the basic principles of the invention.
* * * * *