Note: Descriptions are shown in the official language in which they were submitted.
CA 02434182 2003-07-07
WO 02/057379 PCT/USO1/13757
WATER DISPERSED PRIMERS
FIELD OF THE INVENTION
The present invention relates to primer compositions that may be mixed with
water
and water-based adhesives to provide a range of primers and priming adhesive
compositions
for bond improvement between polymers of similar or dissimilar types.
Compositions
according to the present invention optionally include olefinically unsaturated
monomers or
oligomers for added bond strength after exposure to ultraviolet radiation.
More particularly
the present invention relates primarily to water-based dispersions of surface
modifying
components for enhancing bond formation between substrates, such as
polyolefms, which
are known for low interfacial bond strength. Priming adhesives of the present
invention
improve adhesive bonding between materials without the application of surface
pre-
treatments:
BACKGROUND OF THE INVENTION
Adhesives provide a relatively rapid and convenient way for attaching one type
of
material to another. Over the years, development of adhesive systems has
addressed ways to
modify the strength of the adhesive bond between selected materials. Depending
on the
application, the adhesive of choice may include a pressure sensitive adhesive,
a structural
adhesive, a hot-melt adhesive or a repositionable adhesive. Regardless of the
wide range of
available adhesives, the surfaces of some commonly occurnng polymer substrates
still lack
suitable adhesive affinity to form strong bonds with other materials, whether
similar or
dissimilar. Lack of bonding to surfaces with low adhesive affinity also
affects the bonding
and retention of surface coatings or printing inks that may be used for
surface marking or
decoration.
One solution to poor bond formation and poor retention of coatings and inks
lies in
the use of special treatments to change the condition of a surface by
increasing its surface
energy. Surface treatments for increased surface energy include oxidizing
pretreatments or
the use of adhesion promoters. Oxidizing pre-treatments include the use of
flame,
ultraviolet radiation, corona discharge, and chemical oxidizing agents and the
lilce.
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Adhesion promoters include chemical compositions containing e.g. solutions of
styrene-
ethylene/butylene-styrene block copolymers or acrylate polymers in an orgazuc
solvent.
These compositions improve the bonding of pressure sensitive adhesives and
structural
adhesives to polymer substrates.
Unfortunately, these methods for raising surface energy are not without
problem.
For example, chemical oxidizing agents are typically hazardous materials
requiring special
handling. Surface treatment using flame, corona discharge, etc. usually
requires special
equipment of a design more suited to sheet or film or web processing than to
surface
treatment of shaped articles.
Both oxidizing and adhesion promoter pre-treatments provide improvement in
bond
formation associated with low surface energy polymers such as polyethylene
(PE),
polypropylene (PP), ethylene-propylene-dime terpolymer (EPDM) and ethylene-
alpha
olefin copolymers. Substrates of this type may also include ethylene-vinyl
acetate
copolymers as representative of polymers that are substantially free from
ethylenic
unsaturation.
Polymeric substrates that have some degree of ethylenic unsaturation also
benefit
from the use of surface pre-treatments. It is known, for example, that rubbers
comprising
styrene/butadiene copolymers (SBR) require treatment with chlorinating agents
including
solutions of halogen donors such as trichloroisocyanuric acid, and N,N-
dichlorobenzenesulfonamide, for improved bonding with adhesive bonding agents.
Such
halogen donors may be incorporated into primers or adhesives separately. The
effectiveness
of treatment by chlorination appears somewhat limited to substrates having a
high level of
ethylenic unsaturation such as polybutadiene, polyisoprene, natural rubber,
styrene-
butadiene copolymers, polychloroprene and the like. Also the addition of
halogen donors
reduces the stability of some adhesives, including polyurethane adhesives.
Further improvement in bonding to numerous types of substrates may be possible
by
abrading the surface of a substrate even before applying any pre-treatment.
Mechanical
means for surface roughening then represents a preliminary step to surface pre-
treatments.
Regardless of their effectiveness, pre-treatments represent an additional step
in the process
of manufacturing a product. Additional process steps incur additional time and
expense and
thereby add undesirable cost to a final product.
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The development of primer pre-treatments, primarily in solvent, has yielded
some
improvement in adhesive bonding to low energy surfaces. United States Patent
No. U.5.
6,008,286, for example, provides compositions comprising mixtures of
hydrocarbon
polymers, halogen-substituted hydrocarbon polymers and substituted aliphatic
isocyanates
which, coated from solvent, improve the bond between low energy substrates and
adhesives,
coatings, printing inks and the like. Unfortunately the benefits of solvent-
based primers are
diminished by the need to limit volatile organic compounds (VOC) to a level
that avoids
health hazards and prevents environmental contamination.
Ultraviolet irradiation of solvent-based primers, including chlorinated
polymers,
may lead to modification of polyolefin surfaces. United States Patent No. U.5.
4,303,697
describes the use of a primer containing chlorinated polypropylene applied to
the surface
of a thermoplastic polyolefin. Subsequent exposure to ultraviolet radiation of
the surface
improves the adhesion of paint coatings. United States Patent No. U.5.
4,859,540
compares the benefits of repeated exposure to low intensity ultraviolet
radiation versus a
single exposure to high intensity ultraviolet as a means for improving
adhesion of solvent-
based primers to both adhesives and substrates. Multiple exposures to low
intensity .
ultraviolet radiation is time consuming and probably adds to processing costs.
The description of solvent-based primer solutions and water-based priming
dispersions of chlorinated polymers provided by WO 98/05704 suggests that
coating of
such primers on a polyolefin surface, followed by exposure to ultraviolet
radiation,
improves adhesion to the polyolefin surface. Stabilizers for the water-based
chlorinated
polymer dispersions of WO 98105704 include surfactants, emulsifiers,
thickening agents
and sodium hydroxide. These materials are moisture sensitive and require
careful control
in order to attain a strong and hydrolytically stable bond of the primer to
either a low-
energy substrate or an adhesive.
United States Patent No. U.5. 5,446,083 describes a coating formulation
comprising an aqueous dispersion including an olefinic unsaturated monomer and
a
solution of a chlorinated polyolefin in orgasuc solvent. Stabilization of the
dispersed
phase, of the aqueous dispersion, requires the use of a surfactant.
Unsaturated monomer in
the dispersed phase becomes polymerized upon exposure to heat, ultraviolet
radiation or
electron beam radiation. This reference indicates lack of compatibility
between
chlorinated polyolefm compositions and film forming polymers including
polyurethanes
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WO 02/057379 PCT/USO1/13757
and acrylic polymers. To add further confusion, United States Patent U.S.
5,446,083
teaches successful use of coatings containing chlorinated polyolefins in the
presence of
polymerizable acrylate monomers, suspension polymerized polyacrylates or
mixtures
thereof.
Solvent based or aqueous based thermosettable primers may be used, for bond
improvement, without a flame or corona preliminary treatment. United States
Patent No.
U.5. 6,001,469 describes primers and topcoats of this type used with e.g.
thermoplastic
polyolefins (TPO) and reaction injection molded polyurethane (RIM). These
materials may
be suitably cured on the substrate at temperatures in the region of
130°C for 30 minutes.
Similarly WIPO publication WO 94128077 describes aqueous-based compositions
requiring
heat treatment at 130°C for 40 minutes. It is l~nown (see e.g. R. Ryntz
in "Waterborne, High
Solids Powder Coatings Symposium," Uuv. of Southern Mississippi 1995), that
high
temperature treatment may also affect the surface morphology of thermoplastic
polyolefin
polymers. Such changes may be beneficial in some cases, but in others the
relatively high
temperature for curing may be sufficiently close to the material melting point
to produce
substrate dimensional changes and associated problems.
Attempts to include primer compositions and/or adhesion promoter compositions
with adhesive or coating compositions, have met with limited success.
According to an
article in the Journal of Coating Technology, 65, No. 827 p. 21 (1993), it is
l~nown that
chlorinated polyolefin primer compositions do not provide the same level of
priming when
included as an adhesive additive. The chlorine content of a chlorinated
polyolefin affects
its use as a primer or coating additive. A chlorinated polyolefin having a
chlorine content
below 30 wt% on a 15,000 number average molecular weight polymer will be
incompatible with most coating resins. It is l~nown that effective priming
compositions
typically have a chlorine content less than 30 wt.%. However, high chlorine
content could
also lead to poor priming performance because of solubility of such primers in
solvent-
based topcoat compositions.
Similar limitation of use applies to water based adhesive compositions and
primers
for polyolefins, described in United States Patent No. U.5. 5,298,552. These
compositions
appear primarily useful for applications requiring bonding of polyolefin
sheets to porous
fibrous substrates such as water-absorbent paper board and similar paper pulp
or wood fiber
products. Also, in this case, the composition of the adhesive component of the
formulations
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WO 02/057379 PCT/USO1/13757
appears to have more impact on the bonding force developed between a
polyolefin and
absorbent substrate than the chlorinated polyolefm. It appears that common
solvents, such
as toluene, xylene etc. area unsuitable for use with compositions described in
United States
Patent No. U.S. 5,298,552. Instead, the preferred solvent is relatively
uncommon dodecyl
benzene.
I~zown water based primer compositions derive their stability from the use of
conventional surfactant materials to keep active components dispersed in the
aqueous
phase. The amount of surfactant requires careful control. Insufficient
surfactant leads to
instability and precipitation of the dispersed phase. Addition of too much
surfactant
produces a primer having poor adhesion to substrates that require priming.
Good adhesion
is essential to effective performance of priming compositions.
Tn view of the above described deficiencies associated with the use of known
adhesive bonding agents, particularly the use of multiple treatments at
substrate surfaces, the
present invention has been developed to alleviate these drawbacks and provide
further
improvement and cost reduction. These enhancements and benefits are described
in greater
detail hereinbelow with respect to several alternative embodiments of the
present invention.
SUMMARY OF THE INVENTION
The present invention in its several disclosed embodiments alleviates the
drawbacks
described above with respect to water-dispersed primers and priming adhesive
compositions
and incorporates several additionally beneficial features. Of particular
interest is the
provision of primer solutions suitable for mixing with water and aqueous based
adhesive
dispersions to provide water dispersed primers and priming adhesive
compositions.
Depending upon the application, the variation of dispersed primer relative to
dispersed
adhesive produces a range of compositions from those functioning essentially
as primers to
2 5 others that contribute properties of priming and placement of an adhesive
on a treated
surface. Water dispersed primers and priming adhesives, according to the
present invention,
allow substantial reduction i11 the use of solvents. Solvent removal provides
the benefit of
substantial elimination of volatile orgazuc compound (VOC) emission during
improved
processing and bond formation between polymer substrates. Improved processing
refers to
the elimination of pre-treatments, such as flame and corona treatments, and
the beneficial
use of ultraviolet radiation for improved adhesive bonding using primers and
priming
adhesives according to the present invention.
5°
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More specifically the present invention provides a water dispersed primer
composition comprising a solution of a halogenated hydrocarbon polymer in
organic solvent
and a dispersing agent added to the solution to form a fluid primer to be
dispersed in water
to provide the water dispersed primer composition. Organic solvents may be
selected from
cyclohexane, heptane, hexane, xylene, toluene, chlorotoluene, mixed
hydrocarbon solvents
and mixtures thereof.
The present invention further includes a water based priming adhesive
composition
comprising an adhesive dispersion of an adhesive polymer dispersed in water,
and a
primer mixed with the adhesive dispersion to form the priming adhesive. The
primer
comprises a solution of a halogenated hydrocarbon polymer in organic solvent
selected from
the group consisting of cyclohexane, heptane, hexane, xylene, toluene,
chlorotoluene, mixed
hydrocarbon solvents and mixtures thereof A primer composition may optionally
contain a
particulate dispersing agent.
A photoreactive, fluid primer composition, according to the present invention
comprises a solution having a halogenated hydrocarbon polymer dissolved in an
organic
solvent selected from the group consisting of cyclohexane, heptane, hexane,
xylene, toluene,
chlorotoluene, mixed hydrocarbon solvents, and mixtures thereof, and further
including a
dispersing agent.
Optionally, fluid primer compositions may include organic solvent soluble
halogenated hydrocarbon polymers, photoreactive components and combinations
thereof.
A photoreactive water dispersed primer composition comprises water and a fluid
primer composition as described previously.
Definitions
The following definitions clarify the meaning of terms used herein:
The term, "water-based" may be used interchangeably with the term "water
dispersed" to indicate a composition having a fluid primer as a dispersed
phase in water.
The term, "fluid primer" refers to a solution of polymers and optionally
monomers
and, oligomers in organic solvents that also contain a dispersing agent.
The term "photoreactive component" refers to monomeric or oligomeric species
that
react to form polymers or crosslinl~ed polymers under the influence of actinic
radiation.
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WO 02/057379 PCT/USO1/13757
The beneficial effects described above apply generally to water dispersed
primers,
priming adhesives and related compositions. Specific compositions providing
these benefits
will be described in detail hereinbelow.
DETAILED DESCRIPTION OF THE INVENTION
As required, detailed embodiments of the present invention are disclosed
herein,
however, it is to be understood that the disclosed embodiments are merely
exemplary of the
various and alternative forms of the invention. Therefore, specific structural
and fiuxtional
details disclosed herein are not to be interpreted as limiting, but merely as
a basis for the
claims and as a representative basis for teaching one spilled in the art to
variously employ
the present invention.
Water dispersed primers and primilig adhesives, according to the present
invention,
may be produced by adding a solution of a primer, in organic solvent, to
water, or to a water
dispersed adhesive composition or to a solvent based adhesive. The resulting
compositions
improve adhesive bonding to surfaces known to have low affinity for adhesive
bond
formation. Adhesive bonding improves even in the absence of oxidizing pre-
treatments and
conventional adhesion promoters.
Commonly owned United States Patent No. U.S. 6,008,286 provides solutions of
surface priming compositions dissolved in organic solvents. These priming
compositions
improve bonding of e.g. adhesives, inks and other coatings to substrates
including organic
high polymers that can be synthetic or natural and typically include
elastomeric materials.
The benefits of the previously discussed solutions of primers in organic
solvent may
be realized, according to the present invention, using primer compositions
dispersed in water
or aqueous adhesive dispersions. Combinations of differing quantities of
primer solutions
with water and water dispersed adhesives provide a range of compositions that
either behave
simply as surface primers or priming adhesives. Surfaces primed with these
water-based
dispersions participate in strong adhesive bond formation with similar and
dissimilar
substrates. Surface primers and priming adhesives may be applied by spraying,
or brushing,
or wiping, or any other conventional coating method, followed by drying, by
evaporation, to
produce a pruned surface. The use of water dispersed primers and priming
adhesives has
been shown to eliminate the need for pre-treatment of substrate surfaces.
Substrates suitable for use with primers and priming adhesives according to
the
present invention include uniform polymeric sections, filled materials and
foamed materials.
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WO 02/057379 PCT/USO1/13757
They fall mainly into the two classes of ethylenically unsaturated materials
and those
containing little or no ethylenic unsaturation, as follows:
Substrates with ethylenic unsaturation include: polybutadiene, polyisoprene,
styrene-
butadiene copolymer, styrene-butadiene-styrene block copolymer.
Substrates with essentially no ethylenic unsaturation include ethylene-
propylene-
diene terpolymer (EPDM~, styrene-ethylene-butylene-styrene block copolymer,
ethylene-
propylene rubber, butyl rubber, bromo-butyl rubber, ethylene-alpha olefin
copolymer,
polypropylene, polyethylene, polyethylene vinyl acetate, and synthetic leather
and blends
and mixtures thereof.
Water dispersed primer compositions contain active materials based upon
halogenated hydrocarbon polymers dissolved in an organic solvent. A priming
composition
may also include non-halogenated hydrocarbon polymers as a blend with
halogenated
hydrocarbon polymers. Halogenated hydrocarbon polymers may also include
functional
groups such as sulfonate groups, carboxylic acid anhydride groups, hydroxyl
groups,
epoxide groups, carboxylic acid ester groups, carboxylic acid amide groups,
carboxylic acid
groups and the like. Suitable halogenated hydrocarbon polymers include
chlorinated
polyethylene, chlorinated polypropylene, chlorosulfonated polyethylene,
malefic anhydride
modified chlorinated polyethylene and blends and reaction products thereof.
Preferred
halogenated hydrocarbon polymers are chlorinated polypropylenes modified with
malefic
anhydride and available commercially as CP 343-1, available from Eastman
Chemical
Company, Kingsport TN, HARDLEN CY-9122P, available from Toyo I~asei Kogyo,
Ltd.,
Osaka, Japan, and HYPALON CP-826, available from DuPont Dow Elastomers L.L.C.,
Wilmington DE.
Non-halogenated hydrocarbon polymers, suitable for blend formation with
halogenated polymers, may also include functional groups such as: carboxylic
acid
anhydride groups; hydroxyl groups; epoxide groups; carboxylic acid ester
groups;
carboxylic acid amide groups; carboxylic acid groups and the like. Suitable
polymers
include styrene-ethylene/butylene-styrene triblock copolymers (e.g. I~RATON G-
1657
available from Shell Chemical Co., Houston TX), malefic anhydride modified
styrene-
ethylene/butylene-styrene triblock copolymers, malefic anhydride modified
ethylene-
propylene copolymers, malefic anhydride modified polypropylene, malefic
anhydride
modified ethylene vinyl acetate copolymers and ethylene/butylene copolymers
having
CA 02434182 2003-07-07
WO 02/057379 PCT/USO1/13757
terminal hydroxy functionality. Preferred non-halogenated hydrocarbon,
commercially
available polymers include: I~RATON FG-1901X; and HPVM 2203, both available
from
Shell Chemical Co., Houston TX; FUSABOND MC-190D, available from DuPont Canada
Inc., Mississauga, Ontario, Canada; and an ethylene vinyl acetate copolymer
containing
72% ethylene, available from Polysciences Inc., Warrington PA.
Preferred primers and priming adhesives require addition of solutions of
halogenated
hydrocarbon polymers, and optionally their blends with non-halogenated
hydrocarbon
polymers, in organic solvent, to water, water-dispersed adhesives and solution
adhesives.
Other optional components of primer compositions according to the present
invention
include unsaturated photoreactive components preferably ultraviolet radiation
sensitive
monomers and oligomers.
Solvents used in the preparation of surface primer solutions include aliphatic
hydrocarbons, aromatic hydrocarbons and halogenated derivatives thereof.
Suitable
solvents include cyclohexane, heptane, hexane, xylene, toluene, chlorotoluene
and mixed
hydrocarbon solvents, available from Shell Chemical Co., Houston TX, as SHELL
CYCLO
SOL (R) 100 and SHELL CYCLO SOL (R) 150. Preferably, the organic solvent, for
priming compositions, is a mixture including a weight ratio of from 95:5 to
5:95, more
preferably from 80:20 to 20:80, and most preferably from 60:40 to 40:60 of
either
cyclohexane or heptane combined with xylene or SHELL CYCLO SOL (R) 100 or
SHELL
CYCLO SOL (R) 150. Alcohols, aliphatic ketones, and esters of carboxylic acids
may also
be used as solvents or for dispersion stabilization.
Solutions of halogenated hydrocarbon polymers, or their blends with non-
halogenated hydrocarbon polymers in the solvent mixtures, have solids contents
from 0.5
wt.% to 30 wt.%, preferably 2.0 wt.% to 15 wt.%. Solutions of this type may be
added to
water, water dispersed adhesives, aqueous solutions of olefinically
unsaturated species and
solution adhesives to provide primers and priming adhesives according to the
present
invention. Preferably the solutions are dispersed in the dispersion medium
using from 0.1
wt.% to 5.0 wt.% of a dispersing aid such as finned silica. The ratio of a
solution ofprimer
to dispersion phase formulation may be from 90:10 to 10:90, preferably 50:50
to 15:85 and
more preferably 25:75 based on the weights of each material.
Optional inclusion of olefnucally unsaturated species, such as olefinic
monomers
and oligomers, according to the present invention, provides photosensitive
priming
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WO 02/057379 PCT/USO1/13757
compositions that preferably react upon exposure to ultraviolet radiation.
Preferred
olefinic monomers and oligomers include acrylate and substituted acrylate
functionality
having one or more reactive substituents. The term (meth)acrylate, used
herein, refers to a
molecule having either acrylate or methacrylate functionality in its
structure. Suitable
examples of olefinic unsaturated monofunctional monomers include all~yl
(meth)acrylates,
acrylamides, N-allcylacrylamides, vinyl halides and heterocyclic vinyl
compounds.
Multifunctional monomers and oligomers include those having a plurality of
reactive
substituents including di(meth)acrylate, tri(meth)acrylate and tetra-
(meth)acrylate. In
addition, the olefinically unsaturated monomer, oligomer or blend may contain
one or
more functional groups such as carboxylic acid, glycidyl, amino, halogen and
hydroxyl.
Suitable examples include (meth)acrylic, glycidyl (meth)acrylate, 2-hydroxyl
ethyl
(meth)acrylate, 2-hydroxypropyl (meth)acrylate, the reaction products of
hydroxy
functional (meth)acrylates with alkyl or aromatic, saturated or ethylenically
unsaturated
monobasic or dibasic acid anhydrides, 2-dimethylaminoethyl (meth)acrylate, 2-
chloroethyl
(meth)acrylate and the lilce. Others may include malefic anhydride, malefic
acid,
maleimide, bismaleimides, mono and dialkyl malefic acid esters, fumaric acid
and mono
and dialkyl fumaric acid esters.
Acrylate or methacrylate terminated oligomers or polymers may also be used
alone
or in blends suitable examples include water-dispersed polyurethane acrylates
such as NR
440 and NR-3709 available from Neo Resins, Wilmington, MA,
polybutadienediacrylate,
polyurethane acrylates and epoxy acrylates, available from Sartomer Company,
Exton,
PA. They may be present in the water dispersed primer or primer adhesive
compositions
from 0.1 wt.% to 10 wt.%, more preferably from 0.1 wt.% to 5 wt.%. The
olefinic
unsaturated monomers or oligomers or blends thereof may be present only in the
solvent
phase, only in the aqueous phase or both depending upon solubility of the
monomer or
oligomer or blend.
Most commercial sources of ultraviolet radiation can be used to irradiate the
dried,
primed substrate. As used herein, the term "ultraviolet radiation" is intended
to mean all
radiation emitted by an ultraviolet source witlun the wavelength range of 200-
400 nm. It
is important to control the amount of radiation used. Too little radiation
will not
adequately bond the primer to the substrate, while excessive ultraviolet
radiation will
cause degradation of the exposed surface. In the process of this invention, it
is preferred
CA 02434182 2003-07-07
WO 02/057379 PCT/USO1/13757
to adjust the radiation exposure time so that the radiation energy received by
the primed
surface is 0.10-6.0 J/cm2. The optimum radiation energy range is 0.20-3.5
J/cm2.
An ultraviolet arc lamp system commercially available from RPC Industries,
Hayward, CA, uses commercially available 47 cm, high intensity, medium
pressure
mercury vapor lamps (Tradename - FUSION H) operating at approximately 80 W/cm2
to
provide ultraviolet radiation suitable for primer compositions according to
the present
invention.
Primer compositioins according to the present invention may include from 0.5
wt.% to 15 wt.% and preferably 1.0 wt.% to 5.0 wt.% of a photosensitizer or a
photoinitiator . Photosensitizers or photoinitiators may further promote the
reactivity of
the olefinically unsaturated species. Suitable photosensitizers include
benzophenone,
fluorine, anthrone, p-chlorobenzophenone, and mixtures thereof. Representative
photoinitiators include 2-hydroxy-2-methyl-1-phenylpropan-1-one, available as
DAROCUR-1173, 1-hydroxy-cyclohexyl-phenyl ketone, available as IRGACURE-184, 2-
benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, available as
IRGACURE-
369, 2,2 dimethoxy-1,2 Biphenyl ethan-1-one, available as IRGACURE-651, 1-[4-
(2-
hydroxyethoxy)-phenyl]-2-hydroxy-2-methyll-1-propane-1-one, available as
IRGACURE-
2959, and mixtures thereof, all available from CIBA Specialty Chemicals,
Tarrytown, NY.
Dispersing agents provide stability to water based dispersions according to
the
present invention. Suitable dispersing agents include particulate materials
and polymeric
materials. Fumed silica is a preferred particulate dispersing agent. Examples
of suitable
fumed silica include AEROSIL 200, AEROSIL 300, AEROSIL 380, AEROSIL R-812 and
AEROSIL R-972, all available from Degussa Corp., Ridgefield NJ. Polymeric
dispersing
agents include polyurethane polymers and acrylat~ polymers. A preferred
polyurethane
polymer dispersant is DISPERCOLL U-54, available from Bayer Corp., Pittsburgh
PA. An
example of preferred polyacrylate dispersions is HYCAR 2671, available from
B.F. Goodrich
Performance Materials, Cleveland OH.
Optional additives for solutions containing primer, as described above,
include:
silane coupling agents; biocides; fungicides; optical brighteners;
antioxidants; silica;
pigments; dyes and acid scavengers, such as epoxy resins. Such additives, used
alone or in
combination, preferably represent less than 10 wt.% of the water dispersed
formulations.
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Fluid priming compositions, comprising chlorinated hydrocarbon polymers in
organic solvent or solvent mixture and a dispersing agent, when added with
stirring to
water, produce water dispersed primers according to the present invention.
Optional
ingredients for the fluid priming compositions include non-halogenated
hydrocarbon
polymers and reactive components preferably ultraviolet radiation sensitive
monomers and
oligomers having olefinic unsaturation. Similar priming compositions when
added with
stirring to water dispersed adhesives provide adhesive primers according to
the present
invention. A comparable non-aqueous priming adhesive also forms upon addition
of these
priming compositions to solvent-based adhesives.
Adhesives used for the preparation of priming adhesives include water
dispersed
adhesives and solvent-based or solution adhesives. Useful water dispersed
adhesives
include polyurethane lances and acrylate polymer latices and blends thereof.
Suitable
polyurethane latex adhesives comprise from 35% to 60% of polymer solids
dispersed in
water, including DISPERCOLL U-53, DISPERCOLL U-54 and BAYHYDROL DLN, all
of which are available from Bayer Corp., Pittsburgh PA. Acrylate latex
adhesives, having
from 50% to 65% of polymer solids in water, include HYCAR 2671, available from
B.F.
Goodrich Performance Materials, Cleveland OH, and RHOPLEX A-920, available
from
Rohm and Haas Chemical Company, Philadelphia PA.
Solution adhesives, useful for the present invention, may be selected from a
range of
polyurethane adhesives containing from 15 wt.% to 30 wt.% solids dissolved in
a solvent
such as methyl ethyl ketone (MEK). Suitable commercially available
polyurethane
adhesives include DESMOCOLL 306, DESMOCOLL 530, DESMOCOLL KA8741,
DESMOCOLL 620, DESMODUR CB-55N, and DESMODUR CB-72N, all available from
Bayer Corp., Pittsburgh PA; PEARLSTICK 45-60/18, and PEARLSTICK 45-60/25,
available from Aries Technologies Inc., Dervy NH, and MORTHANE CA-100 series
adhesives available from Rohm and Haas Inc., Pluladelphia PA.
For added hydrolytic stability and adhesive strength, polyurethane adhesives
used
herein may employ from 3.0 wt.% to 5.0 wt %, of the total composition, of a
polyfunctional
isocyanate crosslinker. Suitable materials for use in solution adhesives
include:
DESMODUR RFE, available from Bayer Coxp., Pittsburgh PA; andlor IRODUR E-321
available from Rohm and Haas Ine., Philadelphia PA. Crosslinkers used with
aqueous-based
latex adhesives include: DESMODUR DA; and DESMODUR DN, available from Bayer
12
CA 02434182 2003-07-07
WO 02/057379 PCT/USO1/13757
Corp., Pittsburgh PA. Catalysts such as diallcyl tin carboxylates, metal
acetyl acetonates,
metal carboxylates, mixtures of metal acetyl acetonates with tertiary amines
and the lilce
may be used to accelerate reaction between crosslinlcers a~ld adhesive
polymers.
The water dispersed primers and primer adhesives of the present invention are
very
versatile. They may be applied to the cleaned substrate by any suitable means,
dried and
adhesively bonded to give useful bond strengths. The primed substrate may
instead be
irradiated with ultraviolet light and adhesively bonded to give significantly
improved bond
strengths. The primer may be modified by the addition of olefinically
unsaturated
monomers and optionally photosensitizers or photoinitiators, applied to the
substrate, dried
and irradiated with ultraviolet light and adhesively bonded to give further
improved
bonding.
EXPERIMENTAL
Primer Solution Pre arp ation
Example 1
A solvent mixture of 3.0 parts of cyclohexane to 2.0 parts of xylene was
thoroughly
dried over type 4A Grade molecular sieve (available from W.R. Grace and
Company,
Davison Chemical Div., Baltimore, MD).
An amount of 2.0g of malefic anhydride modified chlorinated polypropylene
(HARDLEN CY-9122P, available from Toyo I~asei Kogyo Co. Ltd.) was dissolved in
31.5
g of the dried solvent mixture to provide a 6% solution of the polymer. Fumed
silica (0.3 g
of AERQSIL R-972, available from Degussa Corp., Ridgefield Park, NJ) was added
to the
solution.
Example 2
As for Example 1 except HARDLEN CY-9122P was replaced by a malefic
anhydride modified chlorinated polypropylene designated CP-343-1 available
from
Eastman Chemical Company, Kingsport, TN.
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Example 3
As for Example 1 except in this case the malefic anhych-ide modified
chlorinated
polypropylene was HYPALON CP-826 available from DuPont Elastomers, Wilmington,
DE.
Example 4
A primer composition containing a blend of halogenated hydrocarbon polymers
was prepared by mixing together equal amounts of Example 1 and Example 3.
Example 5
As for Example 1 except HARDLEN CY-9122P was replaced by a mixture of
HARDLEN CY-9122P (1.6 g) with KRATON 1901X (0.4 g maleated styrene-
ethylene/butylene-styrene block copolymer available from Shell Chemical Co.
Houston
TX).
Example 6
As for Example 5 except for the replacement of KRATON 1901X with an
ethylene/butylene copolymer diol HPVM 2203 also available from Shell Chemical
Co.
Example 7
As for Example 5 except for the replacement of KRATON 1901X with an ethylene
vinyl acetate containing 72% ethylene, available from Polysciences W c.,
Warrington, PA.
Example 8
As for Example 5 except for the replacement of KRATON 1901X with a maleated
polyethylene vinyl acetate, available as FUSABOND MC-190 from DuPont Canada
Inc.,
Mississauga, Ontario, Canada.
Example 9
As for Example 5 except for the replacement of I~RATON 1901X with a styrene-
ethylene/butylene-styrene bloclc copolymer, available as KR_ATON G-1657 from
Shell
Chemical Co.
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Example 10
This example,was prepared by mixing 50 parts of the primer composition of
Example 5 with 50 parts of the primer composition of Example 9.
Exam lpell
Equal amounts of the primer compositions of Example 4 and Example 10 were
mixed to provide a blend containing halogenated hydrocarbon polymers with non-
halogenated hydrocarbon polymers.
Exam 1p a 12
As for example 5 except dried CYCLO SOL(R) 100 replaced xylene in the solvent
mixture.
Exam 1p a 13
As for Example 12 without AEROSIL R-972 fumed silica.
Preparation of Primer Compositions Dispersed in Water
Each of the primer compositions of Examples 1-12 was converted into a water
based
primer dispersion by the addition, with stirring, of 3.0 g of a selected
composition to 7.0 g
distilled water. In all cases, the resulting dispersion remained stable for at
least eight hours.
Observation of some separation after twelve hours was easily corrected by
stirring or
shaping to re-establish a stable dispersion.
Preparation of Primer Compositions Containing Adhesive Polymer Dispersed in
Water
Example 14
A 2% solids aqueous dispersion of a polyurethane adhesive was prepared by
diluting 0.5 g of a 50% polyurethane latex adhesive (DISPERCOLL U-54,
available from
Bayer Corp., Pittsburgh PA) with 12 g distilled water. Addition of 3.0 g of
Example 12 to
7.0 g of the diluted adhesive provided a stable primer composition that
combined primer
and adhesive dispersions. The dispersion was uniform and stable for at least
twelve hours.
Example 15
As for the water dispersed primer of Example 14 except for replacement of the
diluted latex adhesive with a 2% solids aqueous dispersion made from 0.25 g of
CA 02434182 2003-07-07
WO 02/057379 PCT/USO1/13757
DISPERCOLL U-54 mixed with 0.25 g of a polyacrylate dispersion in water (HYCAR
2671 available from B.F. Goodrich Performance Materials, Cleveland OH). As
before the
mixed adhesive dispersion was diluted with 12 g of distilled water and 7.0 g
of the product
was used to disperse 3.0 g of the primer composition described in Example 12.
A stable
dispersion was obtained by stirring the primer composition into the diluted
adhesive.
Example 16
Prepared as for Example 14 using in place of Example 12 the composition of
Example 13 which contained no fumed silica. The resulting dispersion was
uniform and
stable for twelve hours.
Example 17
A 2% solids aqueous dispersion of a polyacrylate was prepared by diluting 0.5
g of
a 50% polyacrylate dispersion (HYCAR 2671) with 12 g of distilled water.
Addition of
3.0 g of Example 13 to 7.0 g of the diluted polyacrylate dispersion provided a
stable
primer composition. Shaping or stirring corrected any phase separation that
may have
occurred in approximately twelve hours.
Example 18
Prepared as for Example 15 using the primer composition of Example 13 in place
of that of Example 12.
Preparation of Priming Adhesives Containing Polyurethane Adhesives Dispersed
in Water
Examples 19-27 were prepared by adding 3.0 g of the primer compositions of
Examples 1-3 and 5-10, with stirring, to 7.0 g of DISPERCOLL U-54 (50% solids
dispersion in water) to produce a stable dispersion of a priming adhesive in
water.
Preparation of Priming Adhesiyes Containin~~Acrylate Adhesives Dispersed in
Water
Example 28
A stable uniform dispersion was made by dissolving HARDLEN 9122P (1.8 g) and
KR.ATON 1901X (0.2 g) in a 31.5 g of a dried solvent mixture of 3 parts of
cyclohexane
to 2 parts of CYCLO SOL(R) 100. AEROSIL R-972 fumed silica (0.3 g) was added
to the
solution and the resulting dispersion (3.0 g) was added to 7.0 g of an
acrylate latex
designated as RHOPLEX A-920, available from Rohm & Haas Inc., Philadelphia PA.
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WO 02/057379 PCT/USO1/13757
Example 29
As for Example 29 except for the replacement of RHOPLEX A-920 with an
acrylate latex designated HYCAR 2671 available from B.F. Goodrich Performance
Materials, Cleveland, OH.
Example 30
As for Example 29 except for the replacement of RHOPLEX A-920 with a 50:50
blend of RHOPLEX A-920 with DISPERCOLL U-54.
Examine 31
As for Example 30 except for the replacement of HYCAR 2671 with a 50:50 blend
of HYCAR 2671 with DISPERCOLL U-54.
Example 32
A mixture of CY-9122P (1.6 g) with KRATON 1901X (0.4 g maleated styrene-
ethylene/butylene-styrene block copolymer - Shell Chemical Co. Houston TX) in
dried
mixed solvent as described in Example 1, was added to a polyurethane latex
(7.0 g)
designated BAYHYDROL DLN available from Bayer Corp., Pittsburgh, PA, mixed
with
0.35 g of a polyisocyanate designated DESMODUR KA8703, also known as
DESMODUR DN, both being available from Bayer Corp. to provide a stable
dispersion.
This example provides a non-adhesive priming coating composition which bonds
well to
low surface energy substrates after drying at 60°C for ten (10)
minutes. Such coatings
provide substrate coverage and protection for a variety of applications such
as automotive
applications.
Example 33
A solution (3 g) containing HARDLEN CY-9122P in mixed, dried solvent as in
Example 1 was added to DESMOCOLL 306 (7.0 g), a 20% solution of a polyurethane
adhesive in methyl ethyl ketone containing 1.0 wt.% AEROSIL R-972 dispersed in
the
solution.
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Preparation of Primer Compositions Containing Unsaturated Photoreactive
Components
Example 34
A solvent mixture of 3.0 parts of cyclohexane, 1.5 parts of CYPAR-9 (Shell
Chemical Co., Houston, TX) and 0.5 parts of AROMATIC D-150 (Exxon Chemical
Co.,
Houston, TX) was thoroughly dried over type 4A Grade molecular sieve
(available from
W.R. Grace and Company, Davison Chemical Div., Baltimore, MD).
Material comprising 1.6 g of CY-9122P and 0.2 g of KR.ATON 1901X was
dissolved in 27.7 g of the dried solvent mixture to provide a 6.5% solution of
the polymer.
Fumed silica (0.6 g of AEROSIL R-972, available from Degussa Corp., Ridgefield
Park,
NJ' was added to the solution.
Example 35
A solvent mixture of 3.0 parts of cyclohexane, 2.0 parts of AROMATIC D-150
(Exxon Chemical Co., Houston, TX) was thoroughly dried over type 4A Grade
molecular
sieve (available from W.R. Grace and Company, Davison Chemical Div.,
Baltimore, MD).
Material comprising 2.42 g of CY-9122P, 0.95 g of a 1:1 mixture of IRGACURE
184 and DAROCURE 11730 and 1.45 g of AEROSIL R-972 was added to 76.7 g of the
dried solvent mixture and agitated until soluble material dissolved.
Example 36
As for Example 35 with the addition of 1.2 g of isobornyl methacrylate SR-
423A,
available from Sartomer Company, West Chester, PA.
Exam 1p a 37
As for Example 36, except that 1.2 g of ethyl methacrylate was used in place
of
isobornyl methacrylate.
Exam 1p a 3 8
As for Example 36, except that 1.2 g of malefic acid was used in place of
isobornyl
methacrylate.
Preparation of Photoreactive Primer Compositions Dispersed in Water
Each of the primer compositions of Examples 34, and 36-38 was converted into a
water based primer dispersion by the addition of 3.0 g of a selected
composition to 7.0 g of a
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WO 02/057379 PCT/USO1/13757
mixture of 4.5% DISPERCOLL U-54 in distilled water and stirnng with a
dispersator for
one hour to provide a smooth dispersion which was stable for at least eight
hours. Stirring
or shalung to re-establish a stable dispersion easily corrected any separation
occurring after
twelve hours. The water based dispersion of Example 35, containing 2.6 g of
primer
composition in 7.0 g of diluted DISPERCOLL U-54, was prepared in similar
fashion. In all
cases, the resulting dispersion remained stable for at least eight hours.
Example 39
As for Example 38, except that the amount of DISPECOLL U-54 was increased to
9.0% in deionized water.
Test Results
Sample Preparation:
Canvas specimen preparation: - Canvas specimens were prepared from greige
cotton (49 x
30 threads per inch) No. 10 duck ribbon, available from West Point Pepperell
Inc., Palatine,
IL by cutting the fabric into specimens 38 mm x 100 mm x 1 mm. Approximately
75 mm of
the length of each specimen was coated by brush coating each specimen twice
with an
adhesive (DISPERCOLL U-54) thickened with 0.2% of BORCHIGEL L75N, a thickener
available from Bayer Corp., Pittsburgh, PA with drying at 60°C for
fifteen (15) minutes.
The samples after cooling were conditioned at room temperature for at least
twenty four (24)
hours.
Foam specimen preparation: - Test specimens were made from injection molded
polyethylene vinyl acetate (IMEVA) foam (ECLIPSE 2050), available from Eclipse
Polymers Co. Ltd., Kyeong Nam, Korea. The test specimens measured 25.4 mm x
127 mm
x 15 mm. A solvent mixture of 3 parts of cyclohexane to 2 parts of xylene was
applied to
clean the surface of each test specimen using a solvent-saturated, lintless
tissue (I~IMWIPE
available from Kimberly Clark Corp., Roswell, GA).
The cleaned foam specimens were dried at 60°C for 10 minutes and
coated, wlule
still warm and between 35°C and 45°C with the water dispersed
primers and priming
adhesives previously described in Examples 1-12 and 14-27.
A stronger, more dense injection molded polyethylene vinyl acetate (IMEVA)
foam (ECLIPSE 2000), available from Eclipse Polymers Co. Ltd., Kyeong Nam,
Korea,
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WO 02/057379 PCT/USO1/13757
replaced ECLIPSE 2050 as the foam substrate for coating with the primer
dispersions
prepared using Examples 34-39. Substrate samples of ECLIPSE 2000 were dried
for 5
minutes at 60°C after solvent cleaning and coated while still warm a~ld
between 35°C and
45°C with primer dispersion. The coated samples were dried for 5
minutes at 60°C
followed by exposure to approximately 0.5 J/cm2 of ultraviolet radiation.
Test Sample Preparation: Canvas specimens, prepared as above, and foam
specimens
coated with water dispersed primers of Examples 1-12 and 14-18 were
overcoated, at
approximately the same time, with a brush coating of the adhesive of
DISPERCOLL U-54
to which 4% by weight of a water dispersible polyisocyanate (designated as
DESMODUR
I~AA8703 or DESMODUR DID had been added with stirring. The coated materials
were
then dried at 60°C for five (5) minutes. The adhesive coated sides of
the canvas and foam
specimens were bonded together under a pressure of approximately 10 KPascals
before
conditioning the bonded, laminated samples for approximately three (3) days
under ambient
conditions.
Examples 19-27, previously coated with priming adhesives as described above,
were
similarly bonded to adhesive coated canvas.
Examples 34-38, previously coated with adhesive, were dried and immediately
bonded together under a pressure of 10 I~pa. The resulting samples were
conditioned for
twenty four hours prior to testing.
Alternative Test Sample Preparation: Test samples of Examples 16 - 18 and 39
were also
prepared by bonding a foam specimen coated with priming composition, i.e. no
additional
adhesive, to a canvas specimen, overcoated with adhesive, (DISPERCOLL U-54 to
which
4% by weight of a water dispersable polyisocyanate (DESMODUR I~A8703 or
DESMODUR DI~ had been added with stirring).
Peel Adhesions: Each of the laminated samples was subjected to 180°
peel testing using a
peel tester available from Instron Corp., Canton MA. The peel tester operated
at a jaw
separation speed of 12.7 cm per minute and at least three samples of each of
Examples 1-12
and 14-27 were submitted to testing.
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WO 02/057379 PCT/USO1/13757
Results: Examples 1-12 and 14-27 exhibited adhesions of at least 354 N/100 mm
with
internal failure of the substrate and not the adhesive bond. This indicates
strong bond
formation between dissimilar materials without pre-treating the surfaces as by
plasma.
Acrylate Series adhesives: Specimens of Examples 28-31 were prepared in
similar to
fashion to Examples 1-12 and 14-27.
Results: Examples 28 and 29 gave peel values of 63 N/100 mm, and 58 N/100 mm
thereby
demonstrating effective priming of the IMEVA foam substrate and adhesion of
the canvas
thereto. Examples 30 and 31 recorded values of at least 354 N/100mm with
internal failure
of the substrate polymer.
Photoreactive Primer Compositions: Specimens of Examples 34-39, were prepared
as
indicated previously. In some cases, test samples of this series of priming
dispersions were
prepared without exposure to ultraviolet radiation.
Results: Example 34 recorded a value of 560 N/100mm with exposure to
ultraviolet
radiation. Without exposure to radiation, adhesion values decreased to
approximately 325
N/100mm. This shows the improvement in bond strength due to the presence of
photoreactive components in priming compositions accordilzg to the present
invention.
Examples 35-38 gave test values, with exposure to ultraviolet radiation, of
598
N/100mm, 645 N/100mm, 600 N/100mm and 670 N/100nun respectively.
Using alternative test sample preparation, with immediate bonding of canvas
and
foam test specimens after drying, Example 39 exhibited average peel values of
approximately 500 N/100mm. This indicates the benefits provided by ultraviolet
exposure
in the absence of adhesive overcoating of the primed foam surface.
Alternative Test Surfaces
An ethylene/1-octene polymer elastomer (POE) available as ENGAGE 8003 from
DuPont Dow Elastomers L.L.C., Wilmington, DE was converted into test specimens
100
mm x 25 mm x 6 mm (110 mm x 20 mm x 6 mm for Examples 34-39). A thermoplastic
polyolefin polymer (TPO) available as ETA 3163 from Himont USA Inc., Lansing,
MI was
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WO 02/057379 PCT/USO1/13757
converted into test specimens 110 mm x 25.4 mm x 3.5 mm (110 mm x 20 mm x 3.5
mm
for Examples 34-39). A vulcanized ethylene propylene dime terpolymer (EPDM)
available
as SHORE A-6 from Shin Ho llzc., Pusan, Korea, was converted into test
specimens 127
irnn x 25.4 rmn x 2.5 mm (110 mm x 20 mm x 2.5 mm for Examples 34-39).
All test specimens were cleaned, dried at 60°C for 10 minutes as
previously
described and coated, while still warm, with the latex bonding agent of
Example 22. Canvas
specimens, as previously described, were laminated, with adhesive to adhesive
bonding, to
the specimens coated with Example 22. After conditioning the laminated samples
were
subjected to 180° peel testing.
Results: POE - 447 N/100mm
TPO - 252 N/100mm
EPDM - 271 N/100mm
Test specimens for exposure to ultraviolet radiation were prepared as
described
above before coating, while still warm, with the bonding agent of Example 38.
Dried
coatings were exposed to 0.5 J/cm2 ultraviolet radiation. Canvas specimens, as
previously
described, were laminated, with adhesive to adhesive bonding, to the specimens
coated with
Example 38. After conditioning the laminated samples were subjected to
180° peel testing.
Results: POE - 350 N/100mm
TPO - 290 N/100mm
EPDM - 290 N/100mm
Composition of Styrene-Butadiene Rubber (SBR)
SBR 1502 65 parts
SBR 1904 35 parts
100 parts
Silica 20 phr
Carbon blacl~ 25 phr
Sulfur 1.8 phr
Coumarone-Indene Resin 3.0 phr
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WO 02/057379 PCT/USO1/13757
Zinc Oxide 3.8 phr
Stearic Acid 1.8 phr
N-cyclohexyl-2-benzothiazolsulfonamide 1.1 phr
Phenolic antioxidant 0.8 phr
A rubber having the composition indicated above was compounded and converted
into plaques by Rubber Industries Inc., Shalcopee, MN. Specimens 127 mm x 25.4
mm x
3.1 mm were prepared for testing. Each specimen of SBR rubber was primed with
a
solution of 2% trichloroisocyanuric acid in dry ethyl acetate. The primed
samples were
conditioned at ambient conditions for 30 minutes before applying adhesives as
described for
the preparation of canvas specimens. Specimens of POE and IMEVA foam were
coated
with the latex bonding agent of Example 22 before drying, along with the
adhesive coated
SBR specimens, at 60°C for five (5) minutes. After adhesive to adhesive
lamination, bond
strength was tested using 180° peel.
Results: POE/SBR - 307 N/100rnin
IMEVA/SBR - 360 N/100mm
IMEVA/POE - 406 N/100mm
Comparative Examples C1-C4
Example C 1
This example reflects the teachings of U.S. 4,303,697.
A 1.0% solution of malefic anhydride modified chlorinated polyolefin (CP 343-1
available from Eastman Chemicals Co., Kingsport, TIC was prepared by
dissolving 1.52 g
of CP 343-1 in 148.5 g of xylene.
Exam 1p a CZ
This example reflects the teaclungs of WO 98/105704.
An amount of 3.69 g of CP 343-1 was added to a mixture of 109.8 g toluene and
34.36 g acetone. A photoreactive composition comprising 1.74 g methyl
methacrylate and
0.74 g benzophenone was added to the resulting solution to prepare a solvent-
based primer
solution.
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WO 02/057379 PCT/USO1/13757
Example C3
This example is based on the teachings of WO 98/105704.
An amount of 3.86 g of a polychloroprene dispersion, (DISPERCOLL C-74
available from Bayer Corp.) and 0.59 g CARBOPOL EZ-1, (available from B.F.
Goodrich
Specialty & Chemicals Division, Cleveland OHM was added with stirring to 151.6
g of
deionized water containing 0.97 g NaOH,
Example C4
This example was formulated using a commercially available, water reducible
chlorinated polyolefin (CP-310W, available from Eastman Chemicals Co.,
Kingsport,
TN).
A 2.66 wt.% solution of a water reducible chlorinated polyolefin was prepared
by
adding 10.05 g of CP-310W to 80.25 g of deionized water.
Specimens on solvent cleaned ECLIPSE 2000 (IMEVA) foam were primed using
Examples C1-C4, followed by exposure to 0.5 J/cmz of ultraviolet radiation.
All
specimens were bonded to canvas coated with DISPERCOLL U-54 adhesive, as
described
previously. Values of 180° peel were obtained for samples that were
allowed to condition
at room temperature for twenty four hours prior to testing. The following
table shows an
average of three peel values for each specimen.
180° Peel Adhesions for Comparative Examples C1-C4
Comparative Example Peel Value N/100mm
C1 410
C2 430
C3 90
C4 255
These results show that prior art solvent solutions (i.e. C1) of chlorinated
polyolefins and solvent solutions of chlorinated polyolefins containing an
olefinically
unsaturated monomer, methyl methacrylate (i.e. C2) give acceptable peel
values.
However, water-based dispersions of chlorinated polyolefins (i.e C3 and C4)
give
signiEcantly lower peel values than primer compositions containing
photoreactive
components according to the present invention.
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Priming Coating Compositions
The priming effect of priming compositions, according to the present
invention, may
also be imparted to coating compositions. A water dispersed priming coating
composition,
as in Example 32 was coated on thermoplastic polyolefm polymer (TPO) available
as ETA
3163 from Himont USA Inc., Lansing, MI in the form of test specimens 110 rnrn
x 25.4 mm
x 3.5 mm that had been previously cleaned and heated to evaporate the cleaner.
The coating
was applied while the specimens were still warm, followed by drying at
60°C for ten (10)
minutes. Control samples, omitting tlhe primer solution, were prepared using
the same
procedure. All specimens were conditioned at room temperature for twenty four
(24) hours.
A new razor blade was used for producing intersecting horizontal and vertical
score
marks having a separation of approximately 1.0 mm. A length of adhesive tape
(ScotchTM
Brand 810 MagicTM Tape available from 3M Company, St. Paul MN) was placed in
fun
adhesive contact with the coating before removal by rapid peeling with a
single continuous
pulling action. Four fresh samples of tape were removed in this way from the
bonded
coatings.
Results: Two of three samples coated with the priming coating of Example 32
showed no
coating removal. The third sample lost only three of the tiny squares,
produced by the
scoring procedure. In contrast, the control samples could not be tested
because they released
from the TPO surface without showing any evidence of bonding.
panic Solvent-Based Priming Adhesives
Canvas specimen pre aration: Canvas specimens were prepared from greige cotton
(49 x 30
threads per inch) No. 10 duck ribbon, available from West Point Pepperell W
c., Palatine, IL
by cutting the fabric into specimens 38 mm x 100 mm x 1 mm. Approximately 75
mm of
the length of each specimen was coated by brush coating each specimen twice
with an
adhesive (DESMOCOLL 306) thickened with 1.0% of AEROSIL 972 fumed silica, and
3%
by weight of a polyisocyanate available as IRODUR E-321, from Rohm and Haas
Inc.,
Philadelphia PA. with drying at 60°C for fifteen (15) minutes. The
samples after cooling
were conditioned at room temperature for at least twenty four (24) hours.
Foam specimen preparation: Test specimens were made from injection molded
polyethylene vinyl acetate (IMEVA) foam (ECLIPSE 2050), available from Eclipse
CA 02434182 2003-07-07
WO 02/057379 PCT/USO1/13757
Polymers Co. Ltd., Kyeong Nam, Korea. The test specimens measured 25.4 mm x
127 mm
x 15 mm. A solvent mixture of 3 parts of cyclohexane to 2 parts of xylene was
applied to
clean the surface of each test specimen usiilg a solvent-saturated, lintless
tissue (KIMWIPE
available from Kimberly Clarlc Corp., Roswell, GA).
The cleaned foam specimens were dried at 60°C for 10 minutes and
coated, while
still warm and between 35°C and 45°C with the solvent based
adhesive of Example 33.
Test Sample Preparation: Canvas specimens and foam specimens coated with
solvent-based
adhesives, were prepared at approximately the same time and then dried at
60°C for seven
(7) minutes. The adhesive coated sides of the canvas and foam specimens were
bonded
together under a pressure of approximately 10 KPascals before conditioning the
bonded,
laminated samples for approximately three (3) days under ambient conditions.
Results: All test specimens exhibited 180° peel adhesions of at least
360 N/100mm
indicating substrate failure with the adhesive bond still intact. This
provides examples of
adhesive formulations suitable for applyiilg directly to organic polymer
substrates without
oxidizing or similar pre-treatment.
Primer compositions according to the present invention may be used for bonding
polymeric substrates together or bonding polymeric substrates to other types
of substrate
such as those comprising metal, glass, ceramic, wood, and woven and non-woven
fabrics,
and the life. The bonding of polymer substrates to fabrics finds use in the
manufacture of a
wide variety of articles of clothing including footwear, particularly athletic
footwear where
secure bonding of fabric to elastomeric shoe components is important to the
production of a
lightweight high performance shoe. Common materials used for athletic shoe
manufacture
include fabrics, polymer mid-soles and durable outer soles. Suitable fabrics
include natural
or synthetic leather, nylon, cotton and the like. Foamed mid-soles include
polymers,
copolymers, and blends a~ld mixtures thereof, based on monomers including
ethylene vinyl
acetate, ethylene/1-octene, propylene and suitable dime monomers. Preferred
polymers and
copolymers include polyethylene vinyl acetate (EVA) and ethylene-propylene-
diene
(EPDM) elastomers. Materials suitable as durable outer soles include the
thermosetting
polymers of vulcanized rubbers such as styrene-butadiene rubbers (SBR),
styrene-butadiene
styrene (SBS) blocl~ copolymer rubbers and ethylene-propylene-dime (EPDM)
rubbers.
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WO 02/057379 PCT/USO1/13757
As indicated above, primers and priming adhesives according to the present
invention contribute to strong adhesive bonding of durable rubber outer sole
materials to
foamed mid-sole materials to produce a composite sole or stoclc that bonds
strongly to
material used for shoe upper after primer or priming adhesive treatment. fit
addition, the
water dispersed primers and priming adhesives provide low hazard, low VOC
containing
products for safe use by workers who apply such products, usually by brushing
or open
spray techniques, during labor intensive manufacturing operations.
Water dispersed primers and priming adhesives and related solvent based
systems
have been described herein. These and other variations, wluch will be
appreciated by those
skilled in the art, are within the intended scope of this invention as claimed
below. As
previously stated, detailed embodiments of the present invention are disclosed
herein;
however, it is to be understood that the disclosed embodiments are merely
exemplary of the
invention that may be embodied in various forms.
27
