Reactive plastisol dispersion

This invention relates to a thermosetting plastisol dispersion composition comprising PA0 (1) at least one copolymer of acrylonitrile-butadiene-styrene (ABS) in powder form, which is insoluble in the reactive plasticizer at room temperature and plasticizable at a temperature at or above the fluxing temperature; PA0 (2) a liquid reactive plasticizer member of the group consisting of (a) at least one epoxide resin having an average of more than one epoxide group in the molecule, (b) at least one liquid monomer, oligomer or prepolymer characterized by (1) containing at least one ethylenically unsaturated group and (2) capable of solvating the ABS at the fluxing temperature, and (c) a mixture of (a) and (b); and PA0 (3) an effective amount of either a thermal initiator or photoinitiator for plasticizers present in the composition. The plastisol dispersion after fluxing can form a thermoset sealant, coating or adhesive after the crosslinking reaction.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a thermosettable adhesive sealant or coating 
plastisol dispersion composition which, on heating at or above the fluxing 
temperature but below the flow temperature of the ABS, rapidly provides 
handling strength and which can be crosslinked to give a thermoset seal, 
bond or coating on further heating or irradiation. 
The invention also relates to a process for forming a crosslinked bond, 
seal or coating. 
2. Description of Prior Art 
In general, a plastisol is composed of a high molecular weight polymer 
dispersed in a plasticizer which is a material incorporated in a plastic 
to increase its workability. Upon heating, the plastisol turns to a 
pregelled dispersion, to a gelled dispersion and then to a fused 
dispersion. The viscosity of a plastisol decreases with the increase of 
temperature at the beginning. At a certain temperature, suddenly, the 
viscosity increases sharply and the liquid dispersion turns to an opaque 
solid, a gelled dispersion. This temperature is called minimum fluxing 
temperature defined as the temperature at which a plastisol develops 
sufficient physical integrity to permit being lifted from the fusion 
plate. Upon further heating at a higher temperature, the plastisol turns 
to a clear plasticized plastic. 
To prepare a plastisol, two basic ingredients, a high molecular weight 
polymer powder and a liquid plasticizer, are required to form a stable 
dispersion after blending. Physically, the plasticization process of a 
plastisol is the permeation of the plasticizer into the polymer particle 
to solvate the polymer molecules. The permeation rate (P) depends on the 
diffusion speed of the plasticizer (D) and the interaction between the 
plasticizer and the polymer (S): 
EQU P=D.times.S 
Under the assumption that a polymer is compatible with a certain 
plasticizer, two important factors, the molecular weight (size) and the 
structure of polymer and plasticizer, should contribute to the stability 
of a plastisol which is determined by the diffusibility of the plasticizer 
upon aging. A stable dispersion should not allow the diffusion to occur at 
or below storage temperature. To prevent a plasticizer from diffusing, the 
size of the plasticizer molecules has to be larger than that of the 
polymer free volume. Upon heating, the free volume increases with 
temperature and allows the plasticizer molecule to diffuse into a polymer 
particle when the temperature is high enough. 
Besides the kinetic process of plasticization, the capability of 
plasticization also depends on thermodynamic parameters. The 
plasticization should not occur when the free energy of mixing is greater 
than or equal to zero (.DELTA.G.sub.m .gtoreq.0), even if the size of the 
plasticizer is as ideal as described above. 
Poly(vinyl chloride) and its copolymers, because of their low degradation 
temperature, eliminate hydrogen chloride and form a colored product below 
their melting temperature. Therefore, to use a melt process for these 
polymers without adding a plasticizer is difficult. The invention of 
plastisol technology has allowed these polymers to have excellent 
applicability and become the major polymers used in the plastisol 
industry. Unfortunately, the degradation of these polymers in service 
conditions is still an unacceptable problem in some applications due to 
hydrogen chloride elimination which promotes corrosion in metal and a 
reduction of polymer strength. 
To stabilize PVC plastisols in service and to enhance their service life, a 
crosslinkable, secondary plasticizer has been incorporated with a primary 
plasticizer for plastisol preparation. The secondary crosslinkable 
plasticizer includes reactive vinyl compounds such as trimethylolpropane 
trimethacrylate and tetraethylene glycol dimethacrylate [Dainippon, JP80 
52,335 (1980)]; G. F. Cowperthwalte, SPE Journal, 29, 56, 1973], 
unsaturated polyesters [Dainippon, JP80 21,474 (1980)], diallyl compounds 
[Shin-Nippon Rika, JP72 40,853 (1972)], and epoxy resins [Dunlop, JP81 
100,841 (1981)]. 
To further improve the structural properties and eliminate the problem of 
hydrogen chloride release of the PVC plastisol, the plastisol technology 
was extended to acrylic polymers for the preparation of thermally fusible 
acrylic plastisols. See U.S. Pat. No. 4,125,700, which used esters as 
plasticizers and polyol acrylates as reactive diluents to prepare various 
reactive acrylic plastisols which formed a plasticized 
semi-interpenetrating network after crosslinking reactions. 
U.S. Pat. No. 4,020,966 teaches a plastisol composition containing as a 
resin component a copolymer of a normal alpha-olefin and maleic anhydride 
in combination with a plasticizer and a reactive polyepoxide plasticizer. 
The copolymer of acrylonitrile-butadiene-styrene (ABS) is an engineering 
plastic having extremely good impact resistance. The copolymer can be used 
to modify the impact resistance of another polymer such as polyvinyl 
chloride. See U.S. Pat. No. 3,969,469 and U.S. Pat. No. 4,259,460. 
Using an organic solvent, methyl ethyl ketone, to dissolve an ABS and epoxy 
resin, an adhesive having improved chemical resistance, adhesion, 
flexibility and impact resistance was prepared as taught in U.S. Pat. No. 
3,496,250. However, the use of a solvent generated problems and 
inconvenience. The dissolving of polymeric material is a time-consuming 
process, especially when the polymer has a high molecular weight. 
Furthermore, the use of a solvent leads to pollution and requires a long 
drying period. Also, the solvent-based adhesives containing high molecular 
weight polymer normally have a high viscosity which impedes processability 
unless the concentration is low. A blend containing ABS graft polymer and 
epoxy resin without solvent was also briefly described as being formed on 
a rubber mill which turns the composition into films. Unfortunately, the 
high shear mixer turns the mixture to a solid material which is not 
pumpable and can be applied as an adhesive or a coating only after remelt. 
To prepare a pumpable thermosetting material, the instant invention 
discloses the dispersion of ABS powder in a reactive plasticizer such as 
liquid epoxy resin, liquid acrylic resin or the mixture of the two. This 
invention concerns the preparation of an ideal reactive plastisol which is 
a system containing a reactive or non-reactive polymer powder dispersed in 
a thermosetting plasticizer. The ideal reactive plastisol converts to a 
fused plastisol at minimum fluxing temperature, turns to a clear 
plasticized polymer at clear point and changes to a thermoset material 
after the crosslinking reaction. The characteristics of the reactive 
plasticizer thus include: wide compatibility with the polymer; low vapor 
pressure; high plasticization efficiency; excellent aging stability upon 
storage and crosslinkability upon curing. 
This invention particularly concerns a class of reactive plastisols 
prepared from a copolymer of acrylonitrile-butadiene-styrene (ABS) and a 
reactive plasticizer or a combination of reactive plasticizers. 
In reactive plastisol technology, which is a combination of plastisol and 
thermosetting technologies, the dispersion fuses into a plasticized solid 
at a temperature much lower than the melting point. Because the fluxing 
process is extremely quick, the thermosettable material provides a 
handling strength or B-stage strength in a few seconds. The final cure to 
a thermoset material can then be made to occur either by subsequent 
heating to the cure temperature or by irradiation, e.g., UV in the 
presence of a photoinitiator or by high energy ionizing radiation. 
OBJECTS OF THE INVENTION 
One object of the instant invention is to produce a novel process and 
composition. Another object of the instant invention is to produce a 
plastisol composition which is useful as an adhesive coating or sealant. 
Yet another object of the instant invention is to produce a plastisol 
composition which on curing substantially minimizes or precludes exuding 
or extraction of the plasticizer. Still another object of the invention is 
to produce a plastisol composition which on heating to the fluxing 
temperature acquires handling strength and cures to a thermoset at or 
above said fluxing temperature. Yet another object of the invention is to 
produce a plastisol composition which on heating to the fluxing 
temperature acquires handling strength and cures to a thermoset on 
subjection to radiation. A further object of the instant invention is to 
produce a process which comprises heating a reactive plastisol composition 
to at least its fluxing temperature but below the flow temperature of the 
thermoplast to flux the plastisol and develop handling strength and, 
thereafter, obtain a thermoset material by heating above its curing 
temperature or by irradiation. Other objects will become apparent from a 
reading hereinafter. 
DESCRIPTION OF THE INVENTION 
This invention relates to a reactive plastisol dispersion composition 
comprising 
(1) at least one copolymer of acrylonitrile-butadiene-styrene (ABS) in 
powder form, which is insoluble in the plasticizer at room temperature and 
plasticizable at a temperature at or above the fluxing temperature; 
(2) a liquid reactive plasticizer member of the group consisting of (a) at 
least one epoxide resin having an average of more than one epoxide group 
in the molecule, (b) at least one liquid monomer, oligomer or prepolymer 
characterized by (1) containing at least one ethylenically unsaturated 
group and (2) capable of solvating the ABS at the fluxing temperature and 
(c) a mixture of (a) and (b); and 
(3) an effective amount of either a thermal initiator or photoinitiator for 
either or both group member plasticizers present in the composition. 
The plastisol dispersion after fluxing can form a thermoset sealant, 
coating or adhesive after the crosslinking reaction. 
The plastisol of the invention operates in the same method as conventional 
plastisols. That is, herein the term "plastisol" refers to dispersions of 
finely divided plastic resin particles in a liquid non-volatile 
plasticizer in which the resin is insoluble and cannot be swollen by the 
plasticizer at room temperature. However, at elevated temperatures, the 
resin fluxes, i.e., is substantially completely plasticized by the 
plasticizer so that a homogeneous, solid solution is obtained which forms 
a rubbery plastic mass. At this point the plastisol has handling 
mechanical strength. Further heating at or above the fluxing temperature 
or irradiation results in a thermoset material with ultimate structural 
strength. If only the plasticizer is reactive, it will crosslink to a 
thermoset and form a semi-interpenatrating network. If the reactive 
plasticizer reacts with the ABS, a crosslinked material results. In 
addition to the ABS resin and the plasticizer, the formulation may also 
contain latent curing agents such as thermal initiators and 
photoinitiators, electrically conductive particles, fillers, pigments, 
stabilizers and various conventional compound ingredients. 
The plastisol compositions herein are formed by admixture of 100 parts by 
weight of the ABS resin particles with about 5 to 2,000 parts by weight of 
plasticizer per 100 parts of resin and, when necessary, contain 0.01% to 
10% by weight of the plasticizer of either a latent thermal initiator or a 
photoinitiator. Thereafter, the plastisol admixture is heated at a 
temperature at or above the fluxing temperature which is lower than the 
melting point of the ABS resin for a time sufficient to plasticize the 
resin by the plasticizer to obtain a homogeneous, solid solution which is 
a rubbery mass, i.e., a fluxed product. The fluxed product and reactive 
plastisol are both useful as adhesives or sealants. For example, the solid 
fluxed material can be placed between two adherends and heated at or above 
a temperature whereat either the thermal initiator decomposes and 
initiates curing of the plasticizer or the plasticizer, per se, initiates 
polymerization which results in a cured thermoset adhesive. The reactive 
plastisol dispersion can also be placed between two adherends and heated 
at or above the decomposition temperature of the initiator to flux and 
initiate the polymerization at the same time. Additionally, the reactive 
plastisol dispersion can also be placed between two adherends at least one 
of which is transparent, heated to its fluxing temperature to obtain a 
plastic fluxed product and, thereafter, radiated with UV to obtain a 
thermoset adhesive. 
The copolymers of acrylonitrile-butadiene-styrene (ABS) have been well 
known since about 1946. There are many ways of producing these materials, 
the two most important types of which are: 
1. blends of acrylonitrile-styrene copolymers with butadiene-acrylonitrile 
rubber (referred to below as Type 1); 
2. interpolymers of polybutadiene with styrene and acrylonitrile (referred 
to below as Type 2). 
The Type 1 materials may be produced by blending on a two-roll mill or in 
an internal mixer blending the latices followed by coagulation or spray 
drying. In these circumstances the two materials are compatible and there 
is little improvement in the impact strength. If, however, the rubber is 
lightly crosslinked by the use of small quantities of peroxides, the 
resultant reduction in compatibility leads to considerable improvements in 
impact strength. A wide range of polymers may be made according to the 
nature of each copolymer and the proportion of each employed. 
By altering these variables blends may be produced to give products varying 
in processability, toughness, low temperature toughness and heat 
resistance. 
Although the nitrile rubbers employed normally contain about 35% 
acrylonitrile, the inclusion of nitrile rubber with a higher butadiene 
content will increase the toughness at low temperatures. For example, 
whereas the typical blend cited above has an impact strength of only 0-9 
ft. lb/in notch at -0.degree. F., a blend of 70 parts 
styrene-acrylonitrile, 30 parts of nitrile rubber (35% acrylonitrile) and 
10 parts of nitrile rubber (26% acrylonitrile) will have an impact value 
of 4-5 ft. lb/in notch at that temperature. 
To produce the Type 2 polymers, styrene and acrylonitrile are added to 
polybutadiene latex and the mixture warmed to about 50.degree. C. to allow 
absorption of the monomers. A water soluble initiator such as potassium 
persulphate is then added to polymerize the styrene and acrylonitrile. The 
resultant material will be a mixture of polybutadiene, polybutadiene 
grafted with acrylonitrile and styrene and styrene-acrylonitrile 
copolymer. The presence of graft polymer is essential since 
straight-forward mixtures of polybutadiene and styrene-acrylonitrile 
copolymers are weak. Thus, the range of possible ABS-type polymers is very 
large. Not only may the ratios of the three monomers be varied but the way 
in which they can be assembled into the final polymer can also be the 
subject of considerable modifications. [See J. A. Brydson, Plastics 
Materials, p. 270-271 (1970)] The ABS particles used herein have a 
particle size in the range from about 0.01 to about 1,500 microns. 
The epoxy resin to be used in the composition of the invention comprises 
those materials possessing more than one epoxy, i.e., 
##STR1## 
group. These compounds may be saturated or unsaturated, aliphatic, 
cycloaliphatic, aromatic or heterocyclic and may be substituted with 
substituents, such as chlorine, hydroxyl groups, ether radicals and the 
like. 
The term "epoxy resin" when used herein and in the appended claims 
contemplates any of the conventional monomeric, dimeric, oligomeric or 
polymeric epoxy materials containing a plurality, more than one, e.g., 
1.1,, epoxy functional groups. Preferably, they will be members of classes 
described chemically as (a) an epoxidic ester having two epoxycycloalkyl 
groups; (b) an epoxy resin prepolymer consisting predominately of the 
monomeric diglycidyl ether of bisphenol-A; (c) a polyepoxidized phenol 
novolak or cresol novolak; (d) a polyglycidyl ether of a polyhydric 
alcohol; (e) diepoxide of a cycloalkyl or alkylcycloalkyl hydrocarbon or 
ether; or (f) a mixture of any of the foregoing. To save unnecessarily 
detailed description, reference is made to the Encyclopedia of Polymer 
Science and Technology, Vol. 6, 1967, Interscience Publishers, New York, 
pages 209-271, incorporated herein by reference. 
Suitable commercially available epoxidic esters are preferably, 
3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (Union Carbide 
ERL 4221, Ciba Geigy CY-179); as well as 
bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate (Union Carbide ERL 4289); 
and bis(3,4-epoxycyclohexylmethyl)adipate (Union Carbide ERL 4299). 
Suitable commercially available diglycidyl ethers of bisphenol-A are Ciba 
Geigy Araldite 6010, Dow Chemical DER 331, and Shell Chemical Epon 828 and 
826. 
A polyepoxidized phenol formaldehyde novolak prepolymer is available from 
Dow Chemical DEN 431 and 438, and a polyepoxidized cresol formaldehyde 
novolak prepolymer is available from Ciba-Geigy Araldite 538. 
A polyglycidyl ether of a polyhydric alcohol is available from Ciba Geigy, 
based on butane-1,4-diol, Araldite RD-2; and from Shell Chemical Corp., 
based on glycerine, Epon 812. 
A suitable diepoxide of an alkylcycloalkyl hydrocarbon is vinyl cyclohexene 
dioxide, Union Carbide ERL 4206. 
Other examples include the epoxidized esters of the polyethylenically 
unsaturated monocarboxylic acids, such as epoxidized linseed, soybean, 
perilla, oiticica, tung, walnut and dehydrated castor oil, methyl 
linoleate, butyl linoleate, ethyl 9,12-octadecadienoate, butyl 
9,12,15-octadecatrienoate, butyl eleostearate, monoglycerides of tung oil 
fatty acids, monoglycerides of soybean oil, sunflower, rapeseed, hempseed, 
sardine, cottonseed oil and the like. 
In the instance when the reactive plasticizer is (b) a liquid monomer, 
oligomer or prepolymer, for example, an acrylate, i.e., an acrylate 
terminated prepolymer, of the formula: 
##STR2## 
wherein R is H or CH.sub.3, R.sub.1 is an organic moiety and n is 1 or 
more, 
the compound can be made by various reactants and methods. One of these 
acrylate terminated materials is a polyether polyol urethane polyacrylate 
formed by reacting a polyether polyol with a polyisocyanate and 
end-capping the remaining NCO group with a hydroxyalkyl acrylate. Another 
material may be a polyester polyol urethane polyacrylate formed by 
reacting a polyester polyol with a polyisocyanate and end-capping the 
remaining NCO group with a hydroxyalkyl acrylate. Still another material 
in this category is an epoxy acrylate formed by reacting a diepoxide with 
acrylic acid. Acrylate or methacrylate ester of an epoxy resin used herein 
are commercially available materials. One of such materials is Shell Co.'s 
Epocryl Resin-370 having the idealized structure: 
##STR3## 
This material has a viscosity of 9,000 poises at 25.degree. C. and 
contains 0.02 equivalents epoxide/100 g. The material is formed from the 
reaction of one mole of diglycidyl ether of bisphenol A reacted with two 
moles of acrylic acid. 
Aside from substituted and unsubstituted acrylic acid being used to form 
the compound herein, hydroxyalkyl acrylate half esters of oxalic, malonic, 
succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, phthalic, 
terephthalic, isophthalic acid and mixtures thereof are also operable. 
Thus, a generalized reaction for forming substituted or unsubstituted 
acrylate esters of an epoxy resin is as follows: 
##STR4## 
wherein m is 0 or 1; n is 1 to 4; R.sub.2 and R.sub.3 are H or CH.sub.3 ; 
R.sub.4 is --CH.dbd.CH--, 
##STR5## 
or --(CH.sub.2).sub.p ; p is 0 to 6 and R.sub.1 is an organic moiety with 
the valence of n. Examples of acrylate terminated prepolymers operable 
herein include, but are not limited to, 1,3-butylene glycol diacrylate, 
diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol 
diacrylate, polyethylene glycol 200 diacrylate, tetraethylene glycol 
diacrylate, triethylene glycol diacrylate, pentaerythritol tetraacrylate, 
tripropylene glycol diacrylate, ethoxylated bisphenol-A diacrylate, 
trimethylolpropane triacrylate, di-trimethylol propane tetraacrylate, 
triacrylate of tris(hydroxyethyl)isocyanate, dipentaerythritol 
hydroxypentaacrylate, pentaerythritol triacrylate, ethoxylated 
trimethylolpropane triacrylate, triethylene glycol dimethacrylate, 
ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 
polyethylene glycol-200 dimethacrylate, 1,6-hexanediol dimethacrylate, 
neopentyl glycol dimethacrylate, polyethylene glycol-600 dimethyacrylate, 
1,3-butylene glycol dimethacrylate, ethoxylated bisphenol-A 
dimethacrylate, trimethylolpropane trimethacrylate, diethylene glycol 
dimethacrylate, 1,4-butanediol diacrylate, diethylene glycol 
dimethacrylate, pentaerythritol tetramethacrylate, glycerin 
dimethacrylate, trimethylolpropane dimethacrylate, pentaerythritol 
trimethacrylate, pentaerythritol dimethacrylate and pentaerythritol 
diacrylate. Monoacrylates such as n-hexyl methacrylate, cyclohexyl 
methacrylate and tetrahydrofurfuryl methacrylate are also operable as 
reactive plasticizers herein. In the case where the reactive plasticizer 
(b) is an unsaturated polyester, conventional unsaturated polyesters can 
be used, such as those described in Kirk-Othmer, Encylopedia of Chemical 
Technology, 2nd Ed., Vol. 2, pp. 791-839, incorporated herein by 
reference. That is, conventional unsaturated polyesters operable herein 
are a class of soluble, linear, low molecular weight macromolecules which 
contain both carboxylic ester groups and carbon-carbon double bonds as 
recurring units along the main chain. These resins are usually prepared by 
condensation of (a) ethylenically unsaturated dicarboxylic acids or 
anhydrides to impart the unsaturation, (b) saturated dicarboxylic acids to 
modify the resin and (c) diols. They are represented by the structural 
formula: 
##STR6## 
wherein R.sub.2 and R.sub.3 are alkylene or arylene radicals in the diol 
and saturated acid respectively, and x and y are variable numbers which 
depend upon the composition and condensation conditions. Polyester alkyds 
can be diluted to a fluid state with methacrylates or other vinyl 
monomers. These mixtures are capable of very rapid copolymerization to 
produce strong solids. This free-radical-initiated reaction proceeds via 
an addition mechanism involving the double bonds of both materials and 
leads to formation of a highly crosslinked structure. 
The diol can be propylene glycol, dipropylene glycol, diethylene glycol, 
polypropylene glycol, polycaprolactone diol, butandiol polybutylene glycol 
or mixtures of glycols. When maleic anhydride is used, care must be paid 
to ensure isomerization of the maleate to fumarate. Maleate can be 
isomerized to fumarate catalytically or by the application of heat. 
However, use of isomerization catalysts can lead to crosslinking or other 
undesirable effects on the product. Fortunately, the polyesterification 
reaction is normally carried out at 200.degree. C. or slightly higher, and 
at these temperatures isomerization is concurrent with polyesterification. 
Typical polyester cook times range from 6 to 16 hours at temperatures from 
180.degree. C. to as high as 230.degree. C. Reaction temperatures much 
above 220.degree. C. can be detrimental, leading to side reactions and 
poor color of the product. 
Generally, substitution of fumarate for maleate as the unsaturated portion 
leads to higher flexural strength and modulus, higher hardness values, 
higher heat distortion temperatures and better chemical resistance in the 
cured systems. However, faster polymerization rates are also obtained. 
These differences can be equated to a higher crosslink density from the 
fumarate unsaturation. 
Acid catalysts such as sulfuric acid or p-toluene-sulfonic acid increase 
the rate of both esterification and isomerization, but usually cause color 
formation and other detrimental side reactions. For this reason catalysts 
are generally not used in high-temperature reactions. However, metal salts 
or organometallic compounds are used as catalysts for direct 
esterification. Numerous metal salts have been used for catalyst action 
including, but not limited to, tetrabutyl or tetraoctyl titanate or 
zirconate or stannous oxalate in combination with sodium and zinc 
acetates. 
Other liquid ethylenically unsaturated monomers, oligomers and prepolymers 
operable herein as plasticizers include, but are not limited to, allyl 
alcohol derivatives and other polyenes taught in U.S. Pat. No. 3,661,744 
incorporated herein by reference. In said patent the polyene component may 
be represented by the formula: 
EQU [A]--(X).sub.m 
wherein m is an integer of at least 2, wherein X is a member selected from 
the group consisting of: 
##STR7## 
In the groups (a) to (e), f is an integer from 1 to 9; R is a radical 
selected from the group consisting of hydrogen, fluorine, chlorine, furyl, 
thienyl, pyridyl, phenyl and substituted phenyl, benzyl and substituted 
benzyl, alkyl and substituted alkyl, alkoxy and substituted alkoxy, and 
cycloalkyl and substituted cycloalkyl. The substituents on the substituted 
members are selected from the group consisting of nitro, chloro, fluoro, 
acetoxy, acetamide, phenyl, benzyl, alkyl, alkoxy and cycloalkyl. Alkyl 
and alkoxy have from one to nine carbon atoms and cycloalkyl has from 
three to eight carbon atoms. 
The members (a) to (e) are connected to [A] through divalent chemically 
compatible derivative members. The members (a) to (e) may be connected to 
[A] through a divalent chemically compatible derivative member of the 
group consisting of Si(R).sub.2, carbonate, carboxylate, sulfone, 
##STR8## 
alkyl and substituted alkyl, cycloalkyl and substituted cycloalkyl, 
urethane and substituted urethane, urea and substituted urea, amide and 
substituted amide, amine and substituted amine, and aryl and substituted 
aryl. The alkyl members have from one to nine carbon atoms, the aryl 
members are either phenyl or naphthyl, and the cycloalkyl members have 
from three to eight carbon atoms with R and said member substituted being 
defined above. B is a member of the group consisting of --O--, --S-- and 
--NR--. 
The member [A] is polyvalent; free of reactive carbon-to-carbon 
unsaturation; free of highly water-sensitive members; and consisting of 
atoms selected from the group consisting of carbon, oxygen, nitrogen, 
chlorine, bromine, fluorine, phosphorus, silicon and hydrogen. 
The polyene component has a molecular weight in the range from about 64 to 
15,000, preferably about 200 to about 10,000; and a viscosity in the range 
from essentially 0 to 1 million centipoises at 25.degree. C. as measured 
by a Brookfield Viscometer. 
More particularly, the member [A] of the polyene composition may be formed 
primarily of alkyl radicals, phenyl and urethane derivatives, oxygenated 
radicals and nitrogen substituted radicals. The member [A] may also be 
represented by the formula: 
##STR9## 
wherein j and k are integers greater than 1; R.sub.2 is a member of the 
group consisting of hydrogen and alkyl having one to nine carbon atoms; 
R.sub.3 is a member of the group consisting of hydrogen and saturated 
alkyl having one to nine carbon atoms; R.sub.4 is a divalent derivative of 
the group consisting of phenyl, benzyl, alkyl, cycloalkyl, substituted 
phenyl, substituted benzyl, substituted alkyl and substituted cycloalkyl; 
with the terms alkyl, cycloalkyl and members substituted being defined 
above. 
General representative formulas for the polyenes of the present invention 
may be prepared as exemplified below: 
I. Poly(alkylene-ether) Polyol Reacted with Unsaturated Monoisocyanates 
Forming Polyurethane Polyenes and Related Polymers: 
##STR10## 
II. Poly(alkylene-ester)Polyol Reacted with Unsaturated Monoisocyanates 
Forming Polyurethane Polyenes and Related Polymers: 
##STR11## 
III. Poly(alkylene-ether)Polyol Reacted with Polysiocycanate and 
Unsaturated Monoalcohol Forming Polyurethane Polyenes and Related 
Polymers: 
##STR12## 
In the above formulas, the sum of x+y+z in each chain segment is at least 
1; P is an integer of 1 or more; q is at least 2; n is at least 1; R.sub.1 
is selected from the group consisting of hydrogen, phenyl, benzyl, alkyl, 
cycloalkyl and substituted phenyl; and R.sub.7 is a member of the group 
consisting of: 
EQU CH.sub.2 .dbd.CH--(CH.sub.2)--.sub.n, 
hydrogen, phenyl, cycloalkyl and alkyl. 
A general method of forming one type of polyene containing urethane groups 
is to react a polyol of the general formula R.sub.11 --(OH).sub.n wherein 
R.sub.11 is a polyvalent organic moiety free from reactive 
carbon-to-carbon unsaturation and n is at least 2; with a polyisocyanate 
of the general formula R.sub.12 --(NCO).sub.n wherein R.sub.12 is a 
polyvalent organic moiety free from reactive carbon-to-carbon unsaturation 
and n is at least 2 and a member of the group consisting of an ene-ol, 
yne-ol, ene-amine and yne-amine. The reaction is carried out in an inert 
moisture-free atmosphere (nitrogen blanket) at atmospheric pressure at a 
temperature in the range from 0.degree. to about 120.degree. C. for a 
period of about 5 minutes to about 25 hours. In the case where an ene-ol 
or yne-ol is employed, the reaction is preferably a one step reaction 
wherein all the reactants are charged together. In the case where an 
ene-amine or yne-amine is used, the reaction is preferably a two-step 
reaction wherein the polyol and the polyisocyanate are reacted together 
and, thereafter, preferably at room temperature, the ene-amine or 
yne-amine is added to the NCO-terminated polymer formed. The groups 
consisting of ene-ol, yne-ol, ene-amine and yne-amine are usually added to 
the reaction in an amount such that there is one carbon-to-carbon 
unsaturation in the group member per hydroxyl group in the polyol, and 
said polyol and group member are added in combination in a stoichiometric 
amount necessary to react with the isocyanate groups in the 
polyisocyanate. 
A second general method of forming a polyene containing urethane groups (or 
urea groups) is to react a polyol (or polyamine) with an ene-isocyanate or 
an yne-isocyanate to form the corresponding polyene. The general procedure 
and stoichiometry of this synthesis route is similar to that described for 
polyisocyanates in the preceding. In this instance, a polyol reacts with 
an ene-isocyanate to form the corresponding polyene. 
Polyenes containing ester groups may be formed by reacting an acid of the 
formula R.sub.13 --(COOH).sub.n wherein R.sub.13 is a polyvalent organic 
moiety free from reactive carbon-to-carbon unsaturation and n is at least 
2; with either an ene-ol or yne-ol. The reaction is carried out in an 
inert moisture-free atmosphere (nitrogen blanket) at atmospheric pressure 
at a temperature in the range from 0.degree. to about 120.degree. C. for a 
period of 5 minutes to 25 hours. Usually, the reaction is carried out in 
the presence of a catalyst (p-toluene sulfonic acid) and in the presence 
of a solvent, e.g., benzene at refluxing temperature. The water formed is 
azotroped off of the reaction. 
Another method of making an ester containing polyene is to react a polyol 
of the formula R.sub.11 --(OH).sub.n wherein R.sub.11 is a polyvalent 
organic moiety free from reactive carbon-to-carbon unsaturation and n is 
at least 2; with either an ene-acid or an yne-acid. The reaction is 
carried out in the same manner as set out above for the ester-containing 
polyenes. In practicing this latter technique, however, it may be found 
that ene-acids (or yne-acids) in which the ene (or yne) group is adjacent 
to an activating polar moiety such as: 
##STR13## 
and the like are generally not desirable within the scope of this 
invention, These activated ene compounds are very prone to 
self-polymerization reactions to form vinyl polymers. Excessive amounts of 
self-polymerization of the ene groups in an undesirable side reaction in 
the present invention. 
In forming the aforementioned polyene plasticizer of the present invention, 
catalytic amounts of a catalyst may be employed to speed up the reaction. 
This is especially true in the case where an ene-ol is used to form the 
polyene. Such catalysts are well known to those in the art and include 
organometallic compounds such as stannous octoate, stannous oleate, 
dibutyl tin dilaurate, cobalt acetylacetonate, ferric acetylacetonate, 
lead naphthanate and dibutyl tin diacetate. 
Mixtures of plasticizers in plasticizer (b) with each other are operable in 
weight ratios of 1 to 99 to 99 to 1. Additionally, when plasticizer (b) is 
used in combination with plasticizer (a), i.e., the epoxy resin, it is 
used in amounts ranging from 1 to 95, preferably 5 to 50% by weight of the 
total plasticizer. The addition of plasticizer (b) to plasticizer (a), 
i.e., the epoxy resin, yields greatly improved handling strength on 
fluxing as will be shown in examples hereinafter. 
The thermal initiators used herein for curing plasticizer (b), for example, 
the acrylate terminated monomers, oligomers or prepolymers or the 
polyester portion of the reactive plasticizer are free radical initiators 
selected from substituted or unsubstituted pinacols, azo compounds, 
thiurams, organic peroxides and mixtures thereof. These initiators are 
added in amounts ranging from 0.01 to 10% by weight of the plasticizer. 
The organic peroxides operable are of the general formula: 
EQU R--O--O--(R.sub.1 --O--O).sub.n --R 
wherein n=0 or 1, R is independently selected from hydrogen, aryl, alkyl, 
aryl carbonyl, alkaryl carbonyl, aralkyl carbonyl and alkyl carbonyl and 
R.sub.1 is alkyl or aryl, said alkyl groups containing 1 to 20 carbon 
atoms. 
Examples of operable organic peroxides include, but are not limited to, 
2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 
1,3-bis(t-butylperoxyisopropyl)benzene, 
1,3-bis(cumylperoxyisopropyl)benzene, 2,4-dichlorobenzoyl peroxide, 
caprylyl peroxide, lauroyl peroxide, t-butyl peroxyisobutyrate, benzoyl 
peroxide, p-chlorobenzoyl peroxide, hydroxyheptyl peroxide, di-t-butyl 
diperphthalate, t-butyl peracetate, t-butyl perbenzoate, dicumyl peroxide, 
1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane and di-t-butyl peroxide. 
Examples of azo compounds operable herein include, but are not limited to, 
commercially available compounds such as 2-t-butylazo-2-cyanopropane; 
2,2'-azobis-(2,4-dimethyl-4-methoxy-valeronitrile); 
2,2'-azobis-(isobutyronitrile); 2,2'-azobis(2,4-dimethylvaleronitrile) and 
1,1'-azobis(cyclohexanecarbonitrile). 
The thiurams operable as thermal initiators herein are of the formula 
##STR14## 
wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 taken singly can be 
hydrogen, linear or branched alkyl having from 1 to about 12 carbon atoms, 
linear or branched alkenyl having from 2 to about 12 carbon atoms, 
cycloalkyl having from 3 to about 10 ring carbon atoms, cycloalkenyl 
having from 3 to about 10 ring carbon atoms, aryl having from 6 to about 
12 ring carbon atoms, alkaryl having from 6 to about 12 ring carbon atoms, 
aralkyl having from 6 to about 12 ring carbon atoms and, when taken 
together, R.sub.1 and R.sub.2 and R.sub.3 and R.sub.4 can each be a 
divalent alkylene group --C.sub.n H.sub.2n -- having from 2 to about 12 
carbon atoms, a divalent alkenylene group --C.sub.n H.sub.2n-2 -- group 
having from 3 to about b 10 carbon atoms, a divalent alkadienylene group 
--C.sub.n H.sub.2n-4 -- having from 5 to about 10 carbon atoms, a divalent 
alkatrienylene group --C.sub.n H.sub.2n-6 -- having from 5 to about 10 
carbon atoms, a divalent alkyleneoxyalkylene group --C.sub.x H.sub.2x 
OC.sub.x H.sub.2x -- having a total of from 4 to about 12 carbon atoms or 
a divalent alkyleneaminoalkylene group: 
##STR15## 
having a total of from 4 to about 12 carbon atoms. 
Operable thiurams include, but are not limited to, tetramethylthiuram 
disulfide, tetraethylthiuram disulfide, di-N-pentamethylenethiuram 
disulfide, tetrabutylthiuram disulfide, diphenyldimethylthiuram disulfide, 
diphenyldiethylthiuram disulfide and diethyleneoxythiuram disulfide and 
the like. 
The substituted or unsubstituted pinacols operable herein as a thermal 
initiator have the general formula: 
##STR16## 
wherein R.sub.1 and R.sub.3 are the same or different substituted or 
unsubstituted aromatic radicals, R.sub.2 and R.sub.4 are substituted or 
unsubstituted aliphatic or aromatic radicals and X and Y which may be the 
same or different are hydroxyl, alkoxy or aryloxy. 
Preferred pinacols are those wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 
are aromatic radicals, especially phenyl radical and X and Y are hydroxyl. 
Examples of this class of compounds include, but are not limited to, 
benzopinacol, 4,4'-dichlorobenzopinacol, 4,4'-dibromobenzopinacol, 
4,4'-diiodobenzopinacol, 4,4',4",4"'-tetrachlorobenzopinacol, 
2,4-2',4'-tetrachlorobenzopinacol, 4,4'-dimethylbenzopinacol, 
3,3'-dimethylbenzopinacol, 2,2'-dimethylbenzopinacol, 
3,4-3',4'-tetramethylbenzopinacol, 4,4'-dimethoxybenzopinacol, 
4,4',4",4"'-tetramethoxybenzopinacol, 4,4'-diphenylbenzopinacol, 
4,4'-dichloro-4",4"'-dimethylbenzopinacol, 
4,4'-dimethyl-4",4"'-diphenylbenzopinacol, xanthonpinacol, 
fluorenonepinacol, acetophenonepinacol, 4,4'-dimethylacetophenone-pinacol, 
4,4'-dichloroacetophenonepinacol, 1,1,2-triphenyl-propane-1,2-diol, 
1,2,3,4-tetraphenylbutane-2,3-diol, 1,2-diphenylcyclobutane-1,2-diol, 
propiophenone-pinacol, 4,4'-dimethylpropiophenone-pinacol, 
2,2'-ethyl-3,3'-dimethoxypropiophenone-pinacol, 
1,1,1,4,4,4-hexafluoro-2,3-diphenyl-butane-2,3-diol. 
As further compounds according to the present invention, there may be 
mentioned: benzopinacol-mono methylether, benzopinacol-mono-phenylether, 
benzopinacol and monoisopropyl ether, benzopinacol monoisobutyl ether, 
benzopinacol mono(diethoxy methyl)ether and the like. 
The thermal initiators employed for plasticizer (a) the opoxy resin are 
thermal initiators selected from dicyandiamide, malamine, guanamine, 
polycarboxylic acid polyhydrazides, carboxylic acid imides, imidazole 
derivatives and BF.sub.3 adducts. The thermal initiators for the epoxy 
resin plasticizer are added in amounts ranging from 0.01 to 10% by weight 
of the epoxy resin plasticizer. 
The BF.sub.3 adducts used herein as thermal initiators include, but are not 
limited to, C.sub.6 H.sub.5 NH.sub.2.BF.sub.3, 2,6-Et.sub.2 C.sub.6 
H.sub.3 NH.sub.2.BF.sub.3, EtNH.sub.2.BF.sub.3, sec-Bu.sub.2 NH.BF.sub.3, 
Et.sub.2 NH.BF.sub.3, (C.sub.6 H.sub.5).sub.3 P.BF.sub.3, C.sub.6 H.sub.5 
NMe.sub.2.BF.sub.3, Pyridine.BF.sub.3 and Et.sub.3 N.BF.sub.3, Et.sub.2 
O.BF.sub.3, (HOCH.sub.2 CH.sub.2).sub.3 N.BF.sub.3 and the like. 
Acceleators for the epoxy resin thermal initiators such as monuron, 
chlorotoluron and similar substances are also operable and can be added in 
amounts ranging from 0.1 to 10 parts by weight of the epoxy resin 
plasticizer. 
Photoinitiators for the epoxy resin plasticizer include, but are not 
limited to, onium salts such as sulfonium salts and iodonium salts. 
Diaryliodonium salts operable herein as either a photoinitiator or a 
thermal initiator are those set out in U.S. Pat. No. 4,238,587, and it is 
understood that so much of the disclosure therein relative to the 
diaryliodonium salts is incorporated herein by reference. That is, the 
diaryliodonium salts which can be utilized in the practice of the 
invention are shown as follows: 
EQU [(R).sub.a (R.sup.1).sub.b I].sup.+ [Y].sup.-, (1) 
where R is a C.sub.(6-13) aromatic hydrocarbon radical, R.sup.1 is a 
divalent aromatic organic radical, and Y is an anion, a is equal to 0 or 
2, b is equal to 0 or 1 and the sum of a+b is equal to 1 or 2. Preferably, 
Y is an MQ.sub.d anion where M is a metal or metalloid, Q is a halogen 
radical and d is an integer equal to 4-6. 
Radicals included within R of formula (1) can be the same or different 
aromatic carbocyclic radicals having from 6 to 20 carbon atoms, which can 
be substituted with from 1 to 4 monovalent radicals selected from 
C.sub.(1-8) alkoxy, C.sub.(1-8) alkyl, nitro, chloro, etc. R is more 
particularly phenyl, chlorophenyl, nitrophenyl, methoxyphenyl, pyridyl, 
etc. Radicals included by R.sup.1 of formula (1) are divalent radicals 
such as 
##STR17## 
where Z is selected from --O--, --S--, 
##STR18## 
R.sup.2 is C.sub.(1-8) alkyl or C.sub.(6-13) aryl, and n is an integer 
equal to 1-8 inclusive. 
Metals or metalloids included by M of formula (1) are transition metals 
such as Sb, Fe, Sn, Bi, Al, Ga, In, Ti, Zr, Sc, V, Cr, Mn, Cs, rare earth 
elements such as the lanthanides, for example, Cd, Pr, Nd, etc., 
actinides, such as Th, Pa, U, Np, etc., and metalloids such as B, P, As, 
Sb, etc. Complex anions included by MQ.sub.d are, for example, BF.sub.4., 
PF.sub.6., AsF.sub.6., SbF.sub.6., FeCl.sub.4., SnCl.sub.6., SbCl.sub.6., 
BiCl.sub.5., etc. 
Some of the diaryliodonium salts which can be used in the practice of the 
invention are as follows: 
##STR19## 
Another onium salt operable herein are the sulfonium salts having an 
MF.sub.6 anion where M is P, As or Sb as disclosed in U.S. Pat. No. 
4,417,061 incorporated hereby by reference. Examples of such salts 
include, but are not limited to: 
##STR20## 
These onium salts are added as photoinitiators in an amount ranging from 
0.01 to 10% by weight of the epoxy resin. 
Preferred photoinitiators for plasticizer (b) are the aldehyde and ketone 
carbonyl compounds having at least one aromatic nucleous attached directly 
to the 
##STR21## 
group. Various photoinitiators include, but are not limited to, 
benzophenone, acetophenone, o-methoxybenzophenone, acenapthene-quinone, 
methyl ethyl ketone, valerophenone, hexanophenone, 
alpha-phenylbutyrophenone, p-morpholinopropionphenone, dibenzosuberone, 
4-morpholinobenzophenone, 4'-morpholinodeoxybenzoin, p-diacetylbenzene, 
4-aminobenzophenone, 4'-methoxyacetophenone, benzaldehyde, 
alpha-tetralone, 9-acetylphenanthrene, 2-acetylphenanthrene, 
10-thioxanthenone, 3-acetylphenanthrene, 3-acetylindone, 9-fluorenone, 
1-indanone, 1,3,5-triacetylbenzene, thioxanthen-9-one, xanthrene-9-one, 
7-H-benz[de]anthracen-7-one, 1-naphthaldehyde, 
4,4'-bis(dimethylamino)benzophenone, fluorene-9-one, 1'-acetonaphthone, 
2'-acetonaphthone, 2,3-butanedione, triphenylphosphine, 
tri-o-tolylphosphine, acetonaphthone, benz[a]anthracene 7.12 dione, etc. 
Another class of photoinitiators is the benzoin alkyl ethers, such as 
benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and 
benzoin isobutyl ether. Still another class of photoinitiators are the 
dialkoxyacetophenones exemplified by 2,2-dimethoxy-2-phenylacetophenone 
and 2,2-diethoxy-2-phenylacetophenone. Benzil ketals such as benzil 
dimethyl ketals are also operable herein as photoinitiators. The 
photoinitiators or mixtures thereof are usually added in an amount ranging 
from 0.01 to 10% by weight of plasticizer (b). 
Thus, when the plasticizer is a mixture of plasticizer (a) and (b), a 
mixture of photoinitiators or thermal initiators is employed (depending on 
whether radiation or heat is used) to obtain a fully thermoset product. A 
class of actinic light useful herein for curing is ultraviolet light and 
other forms of actinic radiation which are normally found in radiation 
emitted from the sun or from artificial sources such as Type RS sunlamps, 
carbon arc lamps, xenon arc lamps, mercury vapor lamps, tungsten halide 
lamps and the like. Ultraviolet radiation may be used most efficiently if 
the photocurable composition contains a suitable photoinitiator. Curing 
periods may be adjusted to be very short and hence commercially economical 
by proper choice of ultraviolet source, photoinitiator and concentration 
thereof, temperature and molecular weight and reactive group functionality 
of the plasticizer. Curing periods of about 1 second duration are 
possible, especially in thin film applications such as desired, for 
example, in coatings. 
When UV radiation is used, an intensity of 0.0004 to 60.0 watts/cm.sup.2 in 
the 200-400 nanometer region is usually employed. High energy ionizing 
radiation can also be used for the curing step without the use of 
photoinitiators in the instant invention. If high energy ionizing 
irradiation is used, e.g, electron beam, a dose in the range of 0.01-10 
megarads is employed at a dose rate of 1.0.times.10.sup.4 -4,000 
megarads/second. Any radiation having an energy of greater than 3.0 
electron volts is operable to cause the curing reaction of the instant 
invention. 
In practicing the invention, it is sometimes possible to use a thermal 
initiator for curing the plasticizer which decomposes at a temperature 
lower than the fluxing temperature of the plastisol, especially when the 
composition is quickly heated to the fluxing temperature. This is due to 
the fact that the fluxing rate is much faster than the curing rate at the 
fluxing temperature. Thus, one can heat quickly to the fluxing 
temperature, flux the plastisol and cool down below the decomposition 
temperature of the thermal initiator before curing occurs, thereby 
obtaining a thermoplastic plastisol ready to be cured to a thermoset 
adhesive on reheating. 
The heating step to cure the fluxed solid plastisol is usually carried out 
for a period of 10 seconds to 30 minutes at a temperature of 
100.degree.-300.degree. C., preferably 120.degree.-200.degree. C., which 
is sufficient to fully cure the composition to a solid thermoset adhesive, 
coating or sealant product. 
The heating step using a thermal initiator to cure the fluxed plastisol 
resin composition can be accomplished in several ways. In simple systems, 
the adhesive composition can be applied by manual means to an adherend, 
contacted with another adherend and the assembled system heated in a 
forced air oven until a thermoset bond results. 
Additionally and preferably, elecromagnetic heating can be utilized as a 
faster and more efficient means of curing, especially where the substrates 
to be bonded are plastic materials. In addition to the formation of high 
strength bonds, electromagnetic bonding techniques aid in (a) fast bond 
setting times, and (b) automated part handling and assembly. 
In practicing the instant invention, electromagnetic heating can be 
employed with the adhesive composition herein to adhere (1) plastic to 
plastic, (2) plastic to metal and (3) metal to metal. For example, 
dielectric heating can be used to bond (1) and (2) supra if the adhesive 
composition contains sufficient polar groups to heat the composition 
rapidly and allow it bond the adherends. Inductive heating can also be 
used to bond (1), (2) and (3). That is, when at least one of the adherends 
is an electrically conductive or ferromagnetic metal, the heat generated 
therein is conveyed by conductance to the adhesive composition thereby 
initiating the cure to form a thermoset adhesive. In the instance where 
both adherends are plastic, it is necessary to add an energy absorbing 
material, i.e., an electrically conductive or ferromagnetic material, 
preferably in fiber or particle form (10-400 mesh) to the adhesive 
composition. The energy absorbing material is usually added in amounts 
ranging from 0.1 to 2 parts by weight, per 1 part by weight of the 
adhesive plastisol resin composition prior to fluxing. It is also possible 
to impregnate the plastic adherend at the bonding joint with particles of 
the energy absorbing material in order to use inductive heating, but care 
must be exercised that the plastic is not distorted. 
The particulate electromagnetic energy absorbing material used in the 
adhesive composition when induction heating is employed can be one of the 
magnetizable metals including iron, cobalt and nickel or magnetizable 
alloys or oxides of nickel and iron and nickel and chromium and iron 
oxide. These metals and alloys have high Curie points 
(730.degree.-2,040.degree. F.). 
Electrically conductive materials operable herein when inductive heating is 
employed include, but are not limited to, the noble metals, copper, 
aluminum, nickel, zinc as well as carbon black, graphite and inorganic 
oxides. 
There are two forms of high frequency heating operable herein, the choice 
of which is determined by the material to be adhered. The major 
distinction is whether or not the material is a conductor or non-conductor 
of electrical current. If the material is a conductor, such as iron or 
steel, then the inductive method is used. If the material is an insulator, 
such as wood, paper, textiles, synthetic resins, rubber, etc., then 
dielectric heating can also be employed. 
Most naturally occurring and synthetic polymers are non-conductors and, 
therefore, are suitable for dielectric heating. These polymers may contain 
a variety of dipoles and ions which orient in an electric field and rotate 
to maintain their alignment with the field when the field oscillates. The 
polar groups may be incorporated into the polymer backbone or can be 
pendant side groups, additives, extenders, pigments, etc. For example, as 
additives, lossy fillers such as carbon black at a one percent level can 
be used to increase the dielectric response of the plastisol adhesive. 
When the polarity of the electric field is reversed millions of times per 
second, the resulting high frequency of the polar units generates heat 
within the material. 
The uniqueness of dielectric heating is in its uniformity, rapidity, 
specificity and efficiency. Most plastic heating processes such as 
conductive, convective or infrared heating are surface-heating processes 
which need to establish a temperature within the plastic by subsequently 
transfering the heat to the bulk of the plastic by conduction. Hence, 
heating of plastics by these methods is a relatively slow process with a 
non-uniform temperature resulting in overheating of the surfaces. By 
contrast, dielectric heating generates the heat within the material and is 
therefore uniform and rapid, eliminating the need for conductive heat 
transfer. In the dielectric heating system herein the electrical frequency 
of the electromagnetic field is in the range 1-3,000 megahertz, said field 
being generated from a power source of 0.5-1,000 kilowatts. 
Induction heating is similar, but not identical, to dielectric heating. The 
following differences exist: (a) magnetic properties are substituted for 
dielectric properties; (b) a coil is employed to couple the load rather 
than electrodes or plates; and (c) induction heaters couple maximum 
current to the load. The generation of heat by induction operates through 
the rising and falling of a magnetic field around a conductor with each 
reversal of an alternating current source. The practical deployment of 
such field is generally accomplished by proper placement of a conductive 
coil. When another electrically conductive material is exposed to the 
field, induced current can be created. These induced currents can be in 
the form of random or "eddy" currents which result in the generation of 
heat. Materials which are both magnetizable and conductive generate heat 
more readily than materials which are only conductive. The heat generated 
as a result of the magnetic component is the result of hysteresis or work 
done in rotating magnetizable molecules and as a result of eddy current 
flow. Polyolefins and other plastics are neither magnetic nor conductive 
in their natural states. Therefore, they do not, in themselves, create 
heat as a result of induction. 
The use of the electromagnetic induction heating method for adhesive 
bonding of plastic structures has proved feasible by interposing selected 
electromagnetic energy absorbing materials in an independent adhesive 
composition layer or gasket conforming to the surfaces to be bonded, 
electromagnetic energy passing through the adjacent plastic structures 
(free of such energy absorbing materials) is readily concentrated and 
absorbed in the adhesive composition by such energy absorbing materials 
thereby rapidly initiating cure of the adhesive plastisol composition to a 
thermoset adhesive. 
Electromagnetic energy absorbing materials of various types have been used 
in the electromagnetic induction heating technique for some time. For 
instance, inorganic oxides and powdered metals have been incorporated in 
bond layers and subjected to electromagnetic radiation. In each instance, 
the type of energy source influences the selection of energy absorbing 
material. Where the energy absorbing material is composed of finely 
divided particles having ferromagnetic properties and such particles are 
effectively insulated from each other by particle containing nonconducting 
matrix material, the heating effect is substantially confined to that 
resulting from the effects of hysteresis. Consequently, heating is limited 
to the "Curie" temperature of the ferromagnetic material or the 
temperature at which the magnetic properties of such material cease to 
exist. 
The electromagnetic adhesive composition of this invention may take the 
form of an extruded ribbon or tape, a molded gasket or cast sheet. In 
liquid form it may be applied by brush to surfaces to be bonded or may be 
sprayed on or used as a dip coating for such surfaces. 
The foregoing adhesive plastisol composition, when properly utilized as 
described hereinafter, results in a one component, solvent free bonding 
system which permits the joining of metal or plastic items without costly 
surface pretreatment. The electromagnetically induced bonding reaction 
occurs rapidly and is adaptable to automated fabrication techniques and 
equipment. 
To accomplish the establishment of a concentrated and specifically located 
heat zone by induction heating for bonding in accordance with the 
invention, it has been found that the electromagnetic adhesive plastisol 
compositions described above can be activated and a bond created by an 
induction heating system operating with an electrical frequency of the 
electromagnetic field of from about 5 to about 30 megacycles and 
preferably from about 15 to 30 megacycles, said field being generated from 
a power source of from about 1 to about 30 kilowatts, and preferably from 
about 2 to about 5 kilowatts. The electromagnetic field is applied to the 
articles to be bonded for a period of time of less than about 2 minutes. 
As heretofore mentioned, the electromagnetic induction bonding system and 
improved electromagnetic adhesive compositions of the present invention 
are applicable to the bonding of metals, thermoplastic and thermoset 
material, including fiber reinforced thermoset material. 
The following examples will help to explain, but expressly not limit, the 
instant invention. Unless otherwise noted, all parts and percentages are 
by weight. 
The lap shear strengths of the adhesives were measured on an Instron 
Tensile Tester using the method set out in ASTM D-1002.

EXAMPLE 1 
2.5 g of an acrylonitrile-butadiene-styrene copolymer commercially 
available from Borg-Warner under the tradename "Blendex-311" having a 
particle size smaller than 53 microns were dispersed in 7.5 g of an epoxy 
resin commercially available from Ciba-Geigy under the tradename 
"Araldite-6004" along with 0.5 g of dicyandiamide. The dispersion was 
stable at room temperature. The dispersion was heated at 120.degree. C. 
for 2 minutes whereat it fluxed to a tacky material. The fluxed material 
was then cured at 170.degree. C. for 30 minutes resulting in a tough, 
flexible, thermoset solid. 
EXAMPLE 2 
The reactive plastisol dispersion from Example 1 was applied between 2 cold 
roll steel substrates with 1/2 in..sup.2 overlap. The adherends with the 
plastisol adhesive therebetween were then cured at 170.degree. C. for 30 
minutes. The adhesive provided an impact resistance of 15 in-lb and a lap 
shear strength of 2,800 psi. A further curing at 180.degree. C. for 30 
minutes resulted in an improved strength (impact resistance greater than 
60 in-lb and a lap shear strength of 4,200 psi). 
EXAMPLE 3 
To 10 g of the reactive plastisol of Example 1 was added 0.05 g of 
commercially available cumene hydroperoxide as a vulcanization agent for 
the ABS. The material was then applied between 2 cold roll steel 
substrates with 1/2 in..sup.2 overlap. After heating at 170.degree. C. for 
30 minutes the adhesive showed an improved impact resistance of 25 in-lb 
and a lap shear strength of 3,700 psi. 
EXAMPLE 4 
To 7.5 g of acrylonitrile-butadiene-styrene copolymer (Blendex-311) were 
added 2.5 g of dimethacrylate of diglycidyl ether of bisphenyl A 
commercially available from Shell Chemical Co. under the tradename 
"Epocryl-12" and 0.1 g of benzoyl peroxide. After heating at 160.degree. 
C. for 1 minute a rigid, tough, homogeneous, thermoset solid was obtained. 
EXAMPLE 5 
33.3 g of an acrylonitrile-butadiene-styrene copolymer commercially 
available from Borg-Warner under the tradename "Blendex-311" having a 
particle size smaller than 53 microns were dispersed in 100 g of a liquid 
epoxy resin commercially available from Ciba-Geigy under the tradename 
"Araldite-6004" along with 6 g of dicyandiamide. The dispersion was stable 
at room temperature. The dispersion was applied between 2 cold roll steel 
substrates with a 1/2 in..sup.2 overlap. The adherends with the plastisol 
adhesive therebetween were then cured at 180.degree. C. for 30 minutes. 
The adhesive provided an impact resistance of greater than 60 in-lb and a 
lap shear strength of 4,600 psi. 
EXAMPLE 6 
42.9 of an acrylonitrile-butadiene-styrene copolymer commercially available 
from Borg-Warner under the tradename "ADG-21" having a particle size 
smaller than 53 microns were dispersed in 100 g of an epoxy resin 
commercially available from Ciba-Geigy under the tradename "Araldite-6004" 
along with 6 g of dicyandiamide. The dispersion was stable at room 
temperature. The reactive plastisol dispersion was applied between 2 cold 
roll steel substrates with 1/2 in..sup.2 overlap. The adherends with the 
plastisol adhesive therebetween were then cured at 180.degree. C. for 30 
minutes. The adhesive provided an impact resistance of 20 in-lb and a lap 
shear strength of 3,305 psi. 
EXAMPLE 7 
36.2 g of acrylonitrile-butadiene-styrene copolymer commercially available 
from Borg-Warner under the tradename "Blendex-311" having a particle size 
smaller than 53 microns were dispersed in 100 g of an epoxy resin 
commercially available from Ciba-Geigy under the tradename "Araldite-6004" 
along with 6 g of dicyandiamide. The dispersion was stable at room 
temperature. The reactive plastisol dispersion was applied between 2 cold 
roll steel substrates with 1/2 in..sup.2 overlap. The adherends with the 
plastisol adhesives therebetween were then cured at 180.degree. C. for 30 
minutes. The adhesive provided an impact resistance of greater than 60 
in-lb and a lap shear strength of 4,575 psi. 
EXAMPLE 8 
2.5 g of ABS (Blendex-311, Borg Warner) plastic was dispersed in 7.5 g of a 
reactive plasticizer, Epocryl-12 (a dimethacrylate of diglycidyl ether of 
bis-phenol A from Shell) containing 0.4 g of 
2.2-diethoxy-2-phenylacetophenone as a photoinitiator. The dispersion was 
heated at 120.degree. C. for 5 minutes to form a fluxed, rubbery film 
which was cured under UV light for 2 minutes. The photocuring was carried 
out in a chamber having a Sylvania medium pressure mercury lamp power=60 
watt/in. in a parabolic reflector. A thermoset film resulted. 
EXAMPLE 9 
25 g of an acrylonitrile-butadiene-styrene copolymer, commercially 
available from Borg-Warner under the tradename "Blendex-311", having a 
particle size smaller than 53 microns were dispersed in 69 g of a liquid 
epoxy resin, commercially available from Ciba-Geigy under the tradename 
"Araldite-6044", and 6 g of methyacrylic acid. 4 g of dicyandiamide were 
added to the dispersion. The dispersion was stable at room temperature. 
The dispersion was applied to a cold roll substrate by a drawbar to obtain 
a 20 mil thick coating. The thus coated substrate was cured at 180.degree. 
C. for 30 minutes. Due to fluxing, the coating maintained its integrity 
and did not run. A smooth adhesive thermoset coating was obtained on 
curing.