Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
1 Vinyl resins have been used to coat or cover
a wise variety of materials. Most materials such as
acrylonitrile-,butadiene-styrene (hereinafter referred
to as ABS) may be coated with a vinyl resin without the
use of the adhesive materials simply by dipping or spraying
the material being coated with the resin coating. How-
ever, vinyl resin coverings particularly on materials
like ABS are likely to be nonpermanent, in that a good
bond between the materials is not formed. Within a short
time after coating, peeling and cracking, etc., of
the polymeric surface results. Further, if the coating or
covering is to be used on surfaces which are subject to
frictional contact, e.g., rubbing, etc., the covering
or coating slips.
Several attempts have been made to securely
bond vinyl resin coverings to various materials. Systems
involving preheating of the material being coated, baking
of the covering, etc., have all been used with!~nly
limited success. Presently, vinyl resins which are
utilized in coverings are available as dispersions or
suspensions. The vinyl resin is usually in the form of
a paste dispersion or elastomers in a plasticizer
~plastisol) and paste dispersions of such elastomers
in a plasticizer and a volatile liquid (organisols).
These materials have been particularly difficult to
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1 permanently adhere to surfaces, e.g., polymeric surfaces.
In the use of such systems, it has been necessary to
apply the vinyl resin dispersions only after the
surface to which they are being applied has been treated
with a primer. Various primers, e.g., vinyl butyral
wash primer, have been utilized to aid in bonding of
the vinyl resin dispersion. Among several disadvan-
tages of known primers for vinyl resin include:
insufficient adherence to permit forming andstamping
operations subsequent to coating; the requirement of
critical preheating of surfaces and curing of primer
and/or coatings; a decreased adherency with aging; and
cracking and breaking of the polymeric substrate. It
is theorized that the cracking of the polymeric substrate
is caused to great extent by migration of the plasticizer
from the cured resin dispersions through the primer
into the substrate.
The prior art has attempted to alleviate
these problems by use of primers comprising various
mixtures of acrylic resins. One such mixture comprises
acrylic and epoxy resins. Such mixtures have been
useful particularly where the surface to which the vinyl
dispersion is being bonded is metallic. However, such
mixtures do not adequately bond vinyl resin d;spersions
to polymeric materials, e.g., ABS~ Further, they do
not eliminate cracking and breaking of polymeric substrate
by plasticizer, if the vinyl resin comprises plasticizer.
SUM~ RY OF THE INVENTION
In accordance with the present invention, it has
been found that strong and permanent adhesives useful for
bonding vinyl resin coverings to surfaces, can be made
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1 by employing mixtures of phenoliic resins and metha-
crylate resins having a ~w greater than about 100,000,
preferably about 400,000. Also~ preferably, the
methacrylate resin is a lower a]Lkyl methacrylate, most
preferably, a methyl methacrylate.
If the adhesive is used with vinyl resin coverings,
contains plasticizer, and the plasticizer is no more than
limited in compatibility with the resins, such superior
bonding results, particularly on polymeric suraces, as to
show a synergistic combination.
The adhesive preferably comprises from about
1 per cent to about 95 per cent ~all per cent are by
weight resin solids) phenolic resin and rom about 5
per cent to about 99 per cent methacrylate resin, more
preferably from about 50 per cent to about 80 per cent
phenolic resin and from abou~ 20 per cent to about
50 per cent methacrylate resin, and most preferably from
about 60 per cent to about 70 per cent phenolic resin
and rom about 30 per cent to about 40 per cent metha-
crylate resin.
When the covering comprises plasticizer~
preferably the plasticizer is no more than limited in
compatibility with the resin, i.e., pllthalate plasticizers
It ls theorized that the polymeric mixtures
of this invention act as efficient permanent adhesives
for plasticizer-containing coverings because they resist
migration of the vinyl coating plasticizer.
DESCRIPTION OF THE PREFERRFD EMBODIME~T
The noncracking adhesives of this invention
for bonding vinyl coverings to polymeric surfaces com-
prise mixtures of phenolic resin and methacrylate resins.
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1 Phenolic resins usefu:L with this invention
must be thermosetting and are obtained by the conden-
sation of phenol or substituted phenols with aldehyde such
as formaldehyde, actaledehyde, and urfural. Among
phenolic resins which are particularly useful with this
invention are: phenol-formald0hyde resins such as
DS-9-2816 sold by Jamestown Finishes, Inc., Jamestown,
New York.
The methacrylate resins of this invention
have a Mw greater than 100,000, more preferably, about
400,000. Preferably, the methacrylate resin is a Cl to C4
lower alkyl, most pre~erably a methyl methacrylate resin.
Weight average molecular weight, ~w is defined
as:
~w = ~
where Mi is the molecular weight of particles of chain
length i, and Ni is the number of particles of chain
length i. Since highly polymeric resins are composed
of mixtures o macramolecules, the higher the ~w,
the greater the number of longer chained macramolecules
in the resin.
Examples of methacrylate resins whlch are
useful with this invent~on include those taught by
U. S. 3,150,118 which are Cl to C4 lower alkyl metha-
crylate/l~weT alkyl acrylate copolymers. An example
of a particularly useul methacrylate resin having ~w
about 400,000 is a copolymer of methyl methacrylate and
normal or isobutyl acrylate wherein the methyl methacrylake
comprises from about 40 to 75 wt. per cent of the copolymer
and the normal or isobutyl acrylate comprises rom about
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1 20 to about 50 wt. per cent of the copolymer. A com-
mercially available version of this resin is AcryloidTM
55D~2 sold by Rohm and Haas Company, Philadelphia,
Pennsylvania.
If plasticizers are used in the vinyl coverings
used in conjunction with this invention, they may be
either highly compatible (primary) or limited in com-
patibility (secondary) with the phenolic and methacrylate
resin adhesive mixture. However, if the plasticizer
utilized in the vinyl coating is no more than limited in
compatibility with the resins, the adhesive mixture shows
such superior bonding, i.e., craze or cracking resistance
particularly on polymeric surfaces, characteristics as
to show a synergistic combination. Useful plasticizers
include adipate and sebacate esters, polyols, e.g.,
ethylene glycol and its derivatives, and caster oil.
Most preferred plasticizers having no more than limited
compatibility with the resins include phthalate esters,
i.e., diisodecyl phthalate and/or epoxy tallate, and
those comprising metallic solids, i.e., liquid cadmium
barium zinc stabilizer, sold by Argus Chemical Corp.,
Brooklyn, New York. Least preferred plasticizers having
high compatibility with the resins include phosphates,
i.e., tricresyl phosphate.
It is theorized that the phenolic resin either
macrascopically or molecularly sufficiently reacts witnin
the methacrylate resin matrix actually surrounding the
long chained methacrylate resin molecules, as to provide a
barrier which is virtually inpenetratable by the poly-
vinyl resin plasticizers. This barrier effect is particularly
noted where the plasticizer is no more than limited in
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1 compatibility with the resins.
The resins are commercially available as
solutions which contain -from about 1 to about 20
weight per cent solids in various solvents. When
applying the adhesive to the surface being covered with
the vinyl resin ~spersion, it is preferred that the
commercially available resins after being formed into the
adhesive mixture be mixed with an organic solvent. The
amount of solvent utilized depends on among other
things, the atmospheric temperature, pressure, and
humidity. However, it is preferred that the solvent-
to-adhesive mixture be between about 10:1 and 1:10
by volume, preferably the ratio is about 1:1 by volume.
Though many solvents are suitable, the organic
solvent used preferably comprises blends or mixtures of
alkyl and aryl ketones, aromatic hydrocarbons, and
alcohols. Useful alkyl ketones include methylethyl,
methylisobutyl and diisobutyl ketones and diacetone
alcohol. Among aromatic hydrocarbons useful with this
invention are toluol and high flash naphtha. Alcohols
include 2-methoxy ethynol, alkyl CellusolveTM, etc.
The adhesive mixture of this invention
preferably comprises from about 1 per cent to about
95 per cent phenolic resin, and from about 5 per cent
to about 99 per cent methacrylate resin, more preferably,
the mixture comprises from about 50 per cent to about
80 per cent phenolic resin, and from about 20 per cent
to about 50 per cent methacrylate resin and most prefera-
bly the mixture comprises from about 60 per cent to
about 70 per cent phenolic resin, and from about 30
per cent to about 40 per cent methacrylate resin ~all
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l per cent by weight resin solids).
Various agents may be added by those skilled
in the art to control adhesion kinetics, e.g., curing
agents. Curing agents useful with this adhesive in-
clude polyfunctional amines and acid anhydrides. Examples
o-f poly-functional amines include diethylene triamine,
trethylene tetramine, tetraethlene petamine, and
phenylenediamine-meta. Examples of acid anhydrides
include maleic, dichloromaleic and phthalic anhydrides.
Any of the commercially available vinyl resins
are useful with this invention. Suitable vinyl covering
polymers include copolymers of vinyl chloride and
vinyl acetate. Examples of suitable vinyl materials
include Vinylite~ YHH and QYNL sold by Union Carbide
and Carbon Corporation. However, as above discussed,
the nature of the plasticizer contained in the resin
is of great importance.
Example I
Adhesives are formulated by intermixing varying
amounts of a commercially available phenolic resin solu-
tion, DS-9-2816 (15% solids), sold by Jamestown Finishes,
Inc., Jamestown, New York, and a methacrylate resin, having
a Mw of about 400,000 AcryloidTM, 55D42 (8% solids), sold
by Rohm and Haas Company, Philadelphia, Pennsylvania.
The adhesive is spray or dip coated on an ABS molded
surface which is subsequently covered by injection
molding the following material over the ABS substrate:
Parts
Polyvinyl chloride resin (QYNL) . . . . . . 100
Diisodecyl phthalate . . . . . . . . . . . . 91
Epoxy Phthalate. . . . . . . . . . . . . . . 8
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1 (continued) Parts
CaCO3 . . . . . . . . . . . . . . . . . . . . 20
Stearic Acid. . . . . . . . . . . . . . . . . 1/4
BaCdZn Chelator Stabilizer . . . . . . . . . 2-1/2
The composite is then tested as to the adherence
of the vinyl coating to the ABS before and after aging.
The adhesive strength of the resulting bond is given in
pounds per inch width. The PVC covering has a Durometer
rating of 70 and thus itself tears at around 50 pounds
per inch of width. The following table summarizes the
results of these tests:
adhesive strength*
Parts Parts in lbs./inch of width
55D42 DS-9-2816
methacrylate phenolic
resin resin
solution solution
(8% solids) (15% solids)
1 47-52
7 1 51-53
4 1 51-57
1 1 50-53
1 4 49-57
1 7 47-52
1 10 46-50
*In all cases, the vinyl coating tore before adhesive
failed.
Example 2
ABS Cycolac TTM tensile bars coated with only
methacrylate resin (55D42) and coated with a 1:2, metha-
crylate (55D42) to phenolic resin (DS-9-2816), adhesive
mixture were strained to 0.8 per cent over a 15-1/2 inch
diameter wooden drum. Various plasticizers contained in
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1 vinyl coverings are painted onto the adhesive-covered
surface of the ABS until the surface crazed. The ~ollowing
table sets forth the results of these tests:
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1 As seen in this example, the phosphate
plasticizer 9 which is highly compatible with the adhesive
resin mixture acts to penetrate the resin and attack the
ABS substrate rapidly as compared to the other limited
incompatibility plasticizers showing the synergistic
combination of resins and preferred plasticizers. ..
As various changes could be made in the above
methods and products without denarting from the scope
of the invention, it is in~ended that all matter
contained in the above description shall be interpreted ~.
illustrative and not in a limiting sense.
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