CA1194637A

CA1194637A - Uv and thermally curable, thermoplastic-containing compositions

Info

Publication number: CA1194637A
Application number: CA000418875A
Authority: CA
Inventors: Charles R. Morgan
Original assignee: WR Grace and Co
Current assignee: WR Grace and Co
Priority date: 1982-04-26
Filing date: 1983-01-04
Publication date: 1985-10-01
Also published as: DE3314896A1; FR2525611A1; GB2119810A; GB8310282D0; IT8320776A0; IT8320776A1; IT1161235B

Abstract

UV AND THERMALLY CURABLE, THERMOPLASTIC-CONTAINING_ COMPOSITIONS
Abstract of the Disclosure A UV and thermally curable composition comprising (1) a member of the group consisting of (a) a liquid, ethylenically unsaturated monomer, oligomer or prepolymer of the formula:

wherein R is M or CH3, R1 is an organic moiety and n is at least 2, (b) an epoxy resin containing at least 2 groups, and (c) a mixture of (a) and (b);
(2) a thermal initiator, (3) a photoinitiator, (41 a thermoplastic material, and (5) a non-polymerizable plasticizer for (4).
The exposure of the composition to W radiation and heat in seriatim results in a cured solid product which can be utilized as adhesives, coatings, gaskets, sealants, resists and the like.

Description

-~ his invention is directed to radiation and heat activated compositions. More particularly~ this invention relates to radiation and heat activated compositions comprising a thermoplastic polymer in combination with a plasticizer for the thermoplastic polymer, a photo~
initiator and a thermal initiator~
BACKGROUND OF THE INVENTION
It is known from U. S. Patent 4~20,233 to form cured polythioethers by admixing the composition comprising an ethylenically unsaturated compound containing at least two unsaturated carbon-to-carbon bonds per molecule, a polythiol containing at least two thiol groups per molecule, a photoinitiator and a catalytic amount of a pinacol and, thereafter, subjecting the admixture to UV
radiation and heat. It is also known from U. S. 3,652,733 to form cured polythioether products from a composition comprising a polymerizable plasticizer having an average of 2 5 carbon-to-carbon unsaturated groups per molecule, a thermoplastic polymer selected from the group consisting of polyvinyl chloride and copolymers of vinyl chloride with vinyl acetate, a polythiol, and a photoinitiator by exposing said composition to W radiation after fluxing the thermoplastic polymer at temperatures between 100 and 200~C. The polythiol is a necessary ingredient to assure that the plasticizer is completely cured and thus does not exude from the product. It is further known from U. S~ 4,309,331 to form photosensitive dispersions of acrylic resins in combination with a non-volatile ethylenically unsaturated compound and a photoinitiator.
It is also known from U. S. 4,288,527 to W and heat cure in seriatim compositions of unsaturated acrylic or methacrylic monomers or prepolymers in combination with a photoinitiator and a substituted or unsubstituted pinacol. Fur~her, it is known from British Patent ~',;

,,7 Application 2,046,269A to photopolymerize a composi~ion of an epoxidic prepolymer and a vinyl chloride dispersion polymer in the pre~ence of specific photoinitiators which decompose on exposure to electromagnetic radiation.
One object of the instant invention is to produce a composition which can be dual ~ and heat cured. ~nother object of this invention is to produce cured products by exposing the composition to UV radiation followed by the application of heat. Still another object is to produce a composition which, when applied to an irregular surface containing shadow areas inaccessible to W radiation, will cure in these areas during the heat cure. Yet another object of the invention is to produce a composition which on exposure to W radiation will skin-cure sufficiently to maintain the composition in situ, e. g~, without any runoff or sag so that the composition is properly positioned for the heat cure which follows. Other objects will become apparent from a reading hereinafter.
OUTLINE OF THE PRESENT INVENTION
The present invention is directed to a UV and thermally curable composition comprising ~1) a member of the group consisting of (a) a liquid, ethylenically unsaturated monomer, oligomer or prepolymer of the formula:
O
(CH2=C~~~o~)n Rl R

wherein R is H or CH3, Rl is an organic moiety and n is at least 2, (b) an epoxy resin containing at least 2 ~O~ groups, and (c) a mixture of (a) and (b), ~ ,73

(2) a thermal initiator,

(3) a photoinitiator, and (4~ a thermoplastic material.
In the above composition, the thermplastic material can be added separately or as a plastisol, e. g., a disperson of a vinyl resin in a liquid plasticizer. The exposure of the composi-tion to UV radiation and heat in seriatim results in a cured solid product which can be utilized as adhesives, coatings, gaskets, sealants, encapsulants, resists and the like.
Thus, an ~V and thermally curable composition is provided which comprises:
(1) a liquid, ethylenically unsaturated monomer, oligomer or prepolymer of the formula o (CH2=C-c-o)n Rl wherein ~ is H or CH3, Rl is an organic moiety and n is at least 2, (2) a therma] initiator for (1) selected from the group consisting of substituted or unsubstituted pinacols, azo compounds, thiurams, organic peroxides and mixtures thereof, (3) a photoinitiator for (1) selected from the group consisting of a].dehyde and ketone carbonyl compounds having at least one aromatic nucleus attached directly to the group, benzoin alkyl ethers, diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone,

(4) a thermoplastic material, and

(5) a non-polymerizable plasticizer for (4).

, ,, "

/3 f Vinyl chloride homopolymers and copolymers containing same have excellent resistance ~o chemiçal attack and to abrasion and have good adhesion p~operties. They are therefore well suited for use as protective coatings or adhesives. It is sometimes desirable to apply these vinyl resins in the form of a composition containing a plasticizer, e. g., as a plastisol. While it has been proposed to use polymerizable plasticizers, e. g., diallylphthalate, together with a free radical initiator such as t-butyl perbenzoate which reacts on heating~ the curing of such plasticizers is difficult to control. Furthermore, in c~rrent practice, many heat curable adhesives or sealants are applied at room temperature and then passed through high pressure water cleaning hoses, as in the automotive industry, and then heated to cause the curing reaction. However, during the passage through the wash-off, some or all of the adhesive or sealant is removed causing gaps in the adhesive or sealant resulting in less adhesion or in inadequate sealing. By use of the composition of the instant invention the composition in the form of an adhesive or sealant can be applied at room temperature, exposed for a short time to UV radiation to set the surface to improve wash-off resistance and eliminate sagging and then can be -4a~

finally ~hrough-cured by heatingO Furthermore, in certain systems in which W ligh~ cannot p~netrate because of geometrical constraints causing shadow areas or in systems rendered partially W opaque due to fillers, it is desirable to have a system whic:h is dual UV/heat cured.
By use of a dual cure, the composition exposed to the W
light can be radiation cured and the part of the composition in the shadow areas can be heat cured.
DETAILED DESCRIPTION OF THE INVENTION
It has now been found that cured products can be obtained from a composition comprising ~1) a member of the group consisting of (a~ a liquid, e~hylenically unsaturated monomer~
oligomer or prepolymer of the formula:
O
(CH2=C-c-O )n Rl R

wherein R is ~ or CH3, Rl is an organic moiety and n is at least 2, ~b) an epoxy resin containing at least 2 ~C~ ~ groupS, and (c) a mixture of (a) and (b);
(2) a thermal initiator, (3) a photoinitiator~ and (4) a thermoplastic material.
by exposing said composition to UV radiation and then heat in seriatim.
Although the aforesaid compositions, per sel are operable herein to form useful products, they may also be used in combination with conventional copolymerizable monomeric compounds or reactive diluents. The admixture of the composition of the instant invention with other monomers is employed usually to control viscosity and other application variables such as rate of cure as well as final film properties such as hardness and flexibility. Reactive diluents include, but are not limited to, monofunctional acrylic esters, monofunctional methacrylic esters, styrene, vinyl-toluene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, butadiene, isoprene, chloroprene, divinyl benzene, di(vinyl-phenyl) carbonate, diallyl phthalate/ diallyl carbonate, di-(allylphenyl) carbonate, diallyl furmarate, triallyl isocyanurate, triallyl cyanurate, diallyl chlorendate, diallyl maleate, butyl glycidyl ether, cresyl glycidyl ether, phenyl glycidyl ether and styrene oxide and unsaturated polyesters and mixtures thereof. By the term unsaturated polyesters herein is meant the usual polycondensation products which consist of ester-like linked residues of polyvalent, especially divalent, alcohols, as well as possibly also residues of monovalent alcohols and/or of monovalent carboxylic acids, selected so that residues must contain at least some unsaturated groups. Examples of acids include maleic acid, fumaric acid, itaconic acid, mesaconic acid, citraconic acid, succinic acid, glutaric acid, adipic acid, phthalic acid, tetrachlorophthalic acid, hexachloroendomethylenetetra-hydrophthalic acid, trimellitic acid, benzoic acid,linseed oil fatty acid and ricinoleic fatty acid and mixtures thereof~ Examples of alcohols include ethylene glycol, diethylene glycol, propane, butane and hexane diols, trimethylolpropane, pentaerythritol, butanol and tetrahydrofurfuryl alcohol.
The reactive diluents can be added to the system in amounts ranging up to 90% by weight of the ethylenically unsaturated or epoxy compound or combination thereof, preferably 20 to 50% by weight on the same basis.

The thermoplastic material operable herein is any conventional thermoplastic, preferably a vinyl resin. The vinyl resins include both homopolymer and copolymers of vinyl resins from monomers containing the vinyl radical (CH2=CH-) or vinylidene radical (CH2=C~). The term "copolymers~ includes terpolymers, tetrapolymers, etc.
Vinyl resins from monomers containing the vinyl radical (CH2=CH-) or vinylidene radical (CH2=C~) operable herein as the thermoplastic material include polyvinyl chloride, polyvinylidene chloride, styrene, pslyvinyl acetate, polyvinyl alcohol, polyvinyl formal, polyvinyl fluoride, acrylic and methacrylic acid and their esters~
Operable copolymers of vinyl monomers include copolymers of vinyl chloride and vinyl acetate or a copolymer of vinyl acetate with another vinyl monomer. Copolymers of vinyl monomers and alpha-olefin include ethylene-vinyl acetate copolymerst ethylene-acrylic acid, ethylene-ethylacrylate, ethylene-methyl acrylate, vinyl chloride-propylene and ethylene-vinyl alcohol. Recent additions to the PVC group operable herein include graft copolymers in which ethylene-vinyl acetate and ethylene-propylene diene monomer have been incorporated~
Mixtures of the above can also be used.
The vinyl resins may be added to the composition per se or in the form of a vinyl plastisol. As used herein, the term "vinyl plastisol" refers to a dispersion of the vinyl resin in a liquid plasticizer.
The liquid plasticizer may be an acrylic or methacrylic monomer, oligomer or prepolymer which not only acts as a plasticizer for the vinyl resin thermoplastic material but also is cured on exposure to UV radiation and heat in the presence of a photo- and thermal initiator.
For example, polyvinyl chloride can be admixed with 3~
trimethylolpropane triacrylate plasticizer, a photo-initiator and thermal initiator and subjected to UV
radiation and heat resulting in a cured homogeneous mass.
Epoxodized soya and linseed oils can also be used a5 reactive plasticizers.
The composition may also contain various conventional non-polymerizable plasticizers for the thermoplastic polymer including, but not limited to, dimetbyl adipate, di~n-propyl adipate, dii~obutyl adipate, dibutoxyethyl adipate, bis(2-ethylhexyl~ adipate, diisodecyl adipate, bi (2-ethylhexyl) azelate, diethylene glycol di-benzoate, dipropylene glycol di-benzoate, octylene glycol di-benzoate, tributyl citrate ~acetyl), trist2-ethylhexyl) citrate (acetyl), ~riethylene glycol di-2-ethylhexoate, lS polyethylene glycol di 2-ethylhexoate, butyl phthalyl butyl glycolate, bis(2-ethylhexyl) hexahydroisophthalate, bis~2-ethylhexyl) hexahydrophthalate, hydrogenated terphenyls, bis(2-ethylhexyl) isophthalate, diisodecyl isophthalate, triethyl phosphate, tricresyl phosphate, cre~yl diphenyl phosphate, isooctyl diphenyl phosphate, tributyl phosphate, 2-ethylhexyl diphenyl phosphate, isodecyl diphenyl phosphate, tri-n-hexyl phospAate, bis(2-ethylhexyl)phenyl phosphate, tris(2-ethylhexyl) phosphate, diethyl phthalate, dimethyl phthalate, butyl benzyl phthalate, butyl cyclohexyl phthalate, dibutyl phthalate, di-n-hexyl phthalate, butyl octyl phthalate, butyl decyl phthalate, diisooctyl phthalate7 bis(2-ethylhexyl~ phthalate, di-n octyl phthalate, dicapryl phthalate, diisodecyl phthalate, di-n-nonyl phthalate, di-n-decyl phthalate, ditridecyl phthalate, bis(2-ethylhexyl) sebacate, butyl stearate and bis(2-ethylhexyl) terephthalate~ Additionally, polyesters having various tradenames including Plastolein 9720, commercially available from Emery Industries, Inc~, * Trademark 3~

Santiciæer 462 and 409, co~mercially available from Monsanto Co., Paraplex*G-30, commercially available from Rohm and Haas Co., Harflex 300, commercially available from ~archem DiV., Wallace ~ Tiernan, Inc., NP-10, commercially available from Eastman Chemical Products, Inc., Paraplex G-54, commercially available from Rohm and Haas Co., and Morflex P-50, commercially available from Pfizer ~ Co., Inc , are also operable herein as unpolymerizable plasticizers.
The plastisol formulations typically comprise 100 parts of the vinyl resin with 60 - 100 parts of the plasticizer. The plastisol may include one or more heat stabilizers for the vinyl resin. ~he amount to be employed is determined by consideration of the temperatures to which the composition must be heated for application and the temperatures which will be encountered in use. Generally about 0.5 - 5% by weight of heat stabilizer, based on the vinyl resin, will be e~ployed.
Conventional heat stabilizers used herein include, but are not limited to, basic lead carbonate, lead acetate, lead stereate, lead oleate, calcium stereate, dibutyl tin dilaurate and barium-cadmium tin complexes.
The relative amounts of the thermoplastic material and the curable group member, i. e., the ethylenically unsaturated compound, epoxy resin or mixture thereof, can vary between wide limits depending on the end use. Thus, weight ratios of the curable group member to the thermo plastic material in the range 20~1 to 1:20, preferably in the range 20:1 to 1:5 are operable herein.
The thermal initiators used herein for curing the ethylenically unsaturated compound of the composition are free radical initiators including~ but not limited to, substituted or unsubstituted pinacols, azo compounds, thiurams, organic peroxides, BF3 adducts and mixtures thereofO
~ Trad~mark i3~

The organic peroxides operable are of the general formula:
R t 1 )n wherein n = 0 or 1, ~ is independently selected from hydrogen, aryl, alkyl, aryl carbonyl, alkaryl carbonyl, aralkyl carbonyl and alkyl carbonyl and Rl is alkyl or aryl~ said alkyl groups containing 1 to 20 carbon atoms.
~xamples 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-(eumyl~eroxyisopropyl)benzene, 2,4-dichlorobenzoyl peroxide, caprylyl peroxide, lauroyl peroxide, t-butyl peroxyisobutyrate, benzoyl peroxide, p-chlorobenzoyl peroxide, hydroxyheptyl peroxide, di-t-butyl diper-phthalate, t-butyl peracetate, t-butyl perbenzoate, dicumyl peroxide, 1,1-di(t-butylperoxy)-3,3,5-trimethyl-cyclohexane, di-t-butyl peroxide and t-butyl hydroperoxide.
The organic peroxide is added to the composition in an amount ranging from 0.01 - 10%, preferably 0.1 - 5%, by weight based on the weight of the ethylenically unsaturated compound.
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 l,l'-azobis-(cyclohexanecarbonitrile~.
The azo compound is added to the composition in an amount ranging from 0.001 - 5%, preferably OoOl - 2% by weight based on the weight of the ethylenically unsaturated compound.

-- 1~ --The thiurams operable as thermal initiators herein are of the formula:
S S
Rl ~ N-C-S-S-C-N ~ 3 Rl, R2t R3 and R4 taken singly can bP
hydrogen, linear or branched alkyl having from 1 to about 12 carbon atomsj linear or branched alkenyl having from 2 to about 12 carbon atoms, cycloalkyl having from 3 to about lO ring carbon atoms, cycloalkenyl having from 3 to ahout lO ring carbon atoms, aryl having from 6 to about 12 ring carbon atoms~ arkaryl having from 6 to about 12 ring carbon a~oms, aralkyl having from 6 to about 12 ring carbon atoms and, when taken together, Rl and R2 and R3 and R~ can each be a divalent alkylene group ( C H2n-) having from 2 to about 12 carbon atoms, a divalent alkenylene group (-Cn~2n 2-j having from 3 to about lO carbon atoms, a divalent alkadienylene group (-C H2n 4-) having from 5 to about lO carbon atoms, a divalent alkatrienyl~ne group (-CnH2n 6-~
having from 5 to about lO carbon atoms, a divalent alkylene oxyalkylene group (-CxH2xOcxH2x-) having a total of from 4 to about 12 carbon atoms or a divalent alkyleneaminoalkylene group I-CxH2xNCxH2x~) 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 disulf.ide, diphenyldimethylthiuram disulfide, diphenyl-diethylthiuram disulfide and diethyleneoxythiuram disulfide and the like.

The thiuram is added to the composition in an amount ranging from 0.005-5Oo% by weight of the ethylenically unsaturated compoundO
The substituted or unsubstituted pinacols operable herein as a thermal initiator have the general formula:
~1 R3 X y wherein Rl and R3 are the same or different substituted or unsubstituted aromatic radicals, R2 and R4 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 R1, R2, R3 and R4 are aromatic xadicals, 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, 4j4'-diiodobenzopinacol, 4~4~5 4", 4"'-tetrachlorobenzopinacol, 2,4-2',4'-tetrachloro-benzopinacol, 4,4'-dimethylbenzopinacol, 3,3l-dimethyl-benzo~inacol, 2,2'-dimethylbenzopinacol, 3,4-3'/4'-tetra-methylbenzopinacol, 4,4'-dimethoxybenzopinacol r 4 ~ 4 ~ ~ 4 n ~ 4"'-tetramethoxybenzopinacol, 4,4'-diphenyl-benzopinacol, 4,4'-dichloro-4",4n 1 -dimethylbenzopinacol, 4,4'~dimethyl-4'l,4l"diphenylbenzopinacol, xanthonpinacol, fluorenonepinacol, acetophenonepinacol, 4,4~-dimethylaceto-phenone-pinacol, 4,4'-dichloroacetophenonepinacol, 1,1,2-triphenylpropane-1,2-diol~ 1,2,3,4-tetraphenyl-butane-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-diolO

As further compounds according to the present invention, there may be mentioned: ben7.0pinacol-morlo-methylether, benzopinacol-mono phenylether, benzopinacol and monoisopropyl ether, benzopinacol monoisobutyl ether, 5 benzopinacol mono(diethoxy methyl)ether and the like.
The pinacol is added to the composition in amounts ranging from 0.01 - ln ~, preferably 0.1 - 5%, by weight based on the weight of the ethylenically unsaturated compound.
The BF3 adducts used herein as thermal initiators can be used as thermal initiators for both the ethylenically unsatura~ed compound and the epoxy resin and include, but are not limited to, C6H5NH2-BF3, 2,6-Et2C6H3NH2~BF3' E N 2 3 Sec-gu2NH~BF3~ Et2NH-BF3' (C6H5)3P~BF3 C6H5NMe2-BF3, Pyridine BF3, Et3N~BF3, Et2'~F3 and (HOCH2CH2)3N-BF3- The BF3 adduct is added to the composition in an amount ranging from 0.5 to 10% by weight of either the ethylenically unsaturated compound, the epoxy resin or the combination thereof, whichever is employed.
To photocure the epoxy resins, it is necessary to use an onium salt. U. S. Patents 4,069,055 and 4,058,401 show radiation induced polymerization of epoxides by the use of certain radiation sensitive onium salts of Group Va, VIa and VIIa elements, in particular various aromatic sulfonium salts. Among the most effective compounds for this purpose are salts of the triarylsulfonium cation containing anions that release Lewis Acid when the salts are photodecomposed. Examples of such salts are:

( ~ )-2S+ ~ -S ~ X and (Ph)3S X where X- - BF4~, PF~-, AsF6~, SbF6~, SnC16~, SbC16 , FeC14 , BiC15 AlF ~~~ GaCl ~ I nF ~ T iF - - Z r F -- etc Sulfonium salts of this kind are well known in the literature and have been prepared by a variety of means.
(See Pitt, U. S. Patent NoO 2,807,64~; Knapczyk and McEwen, J. Am. Chem. Soc., 91, 145 (1969); Goethals and Radzitzky, Bull. Soc. Chim. Belg. 73 546 (1964). The complex sulfonium salts can be pr pared from the corresponding simple salts, such as the halide salts, by metathesis with a metal or ammonium salt of the complex anion desired ~s shown in an example hereinafter. These photosensitive onium salts are incorporated herein by reference. The onium salts employed as photoinitiators for the epoxy resin are added in an amount ranging from 0.005 to 25% by weight of the epoxy resin.
Thus; when an ethylenically unsaturated group member and an epoxy resin are added in combination to form a thermoset product, in some instances it is necessary to add as a thermal initiator both the aforementioned free radlcal type and the ionic type in the amounts specified in order to obtain a cocured product.
The thermal and photoinitiators can be added to the system in various ways. That is, the initiators, per se, can be admixed with the ethylenically unsaturated or epoxy group member. Additionally, the initiators can be dissolved or suspended in a minor amount of well known commercially available solvents such as ketones, e.g./ acetone and methyl ethyl ketone or chlorinated hydrocarbons such as methylene chloride, and then added to the systemO
In practicing the instant invention, the components of the composition can be present in widely varying amounts depending on the end use of the composition. That is, the ethylenically unsaturated or epoxy gro~p member or both together can be present in an amount ranging from 5 to 95%
by weiyht with the balance to 100% being made up by the thermoplastic material with or without non-reactive plasticizers, fillers, diluents and other conventional additives. The peroentages of thermal and photoinitiators used have previously been set out herein and are based on the weight percent of the e~hylenically unsaturated or epoxy group member present.
The compositions of the present invention may, if desired, include such additives as antioxidants, dyes, inhibitors, fillers~ pigments, antistatic agents, flame-retardant ayents, thickeners, thixotropic agents, surface-active agents, viscosity modifiers, extending oils, tackifiers and th~ like within the scope of this inventionO Such additives are usually preblended with the ethylenically unsaturated compound or epoxy resin prior to or during the compounding step. Operable fillers include natural and synthetic resins, glass .ibers, wood flour, clay, silica, alumina, carbonates, oxides, hydroxides, silicates, glass flakes, borates, phosphates, diatomaceous earth, talc, kaolin, barium sulfate, calcium sulfate, antimony oxide and ~he like. The aforesaid additives may be present in quantities up to 500 parts or more per 100 parts of the ethylenically unsaturated compound, epoxy resin or combination thereof by weight and preferably about 0.005 to about 300 parts on the same basis.
Additionally, scavengers and antioxidants such as hydroquinone, pyrogallol, phosphorous acid, tert-butyl hydroquinone, tert-butyl catechol, p-benzoquinone, 2,5-diphenylbenzoquinone, 2,6-di-tert-butyl-p-cresol, etc., are added to the system in conventional amounts ranging from 0.001 to 2.0% by weight of the ethylenically unsaturated member.

Epoxy resin stabilizers such as phosphites, e. g., triphenyl phosphite, diphlenyl phosphite and trisnonylphenyl phosphite are added to the system in conventional amounts ranging from 0.001 to 2.0% by weight of the epoxy resin.
In practicing the instant invention the composition is preferably subjected to UV radiation followed by heat activation. It is preferable to add photoinitiators in order to initiate the UV reaction. Preferred photo-initiators are the aldehyde and ketone c~rbonyl compoundshaving at least one aromatic nucleous attached directly to the --C--group. Various pho~oinitiators include, but are not limited to, benzophenone, acetophenone, o-methoxy-benzophenone, acenapthene-quinone, methyl ethyl ketone, valerophenone, hexanophenone, alpha-phenylbutyrophenone, p-morpholinopropionphenone, dibenzosuberone t 4-morpholino-benzophenone, 4'-morpholinodeoxybenzoin, p-diacetyl-benzene, 4-aminobenzophenone, 4'-methoxyacetophenone, benzaldehyde, alpha-tetralone, 9-acetylphenanthrene, 2-acetylphenanthrenel 10-thioxanthenone, 3-acetyl-phenanthrene, 3-acetylindone, 9-fluorenone, l-indanone, 1,3,5-triacetylbenzene, thioxanthen-9-one, xanthrene-9-one, 7-H-benz[de]anthracen~7-one, l-naphthaldehyde, 4,4'-bis(dimethylamino) benzophenone, fluorene-9-one, l'-acetonaphthone, 2' acetonaphthone, 2/3-butanedione, acetonaphthonet 2,3-butanedione, benz[a]anthracene 7.12 dione, 2-hydroxy-2-methyl-1-phenylpropan-1-sne, 1-(4-isopropylphenyl) 2-hydroxy-~-methylpropan-1-one, etc. Another class of photoinitiators is the benzoin ethers, such as benzoin methyl ether, benzoin ethyl ether benzoin isopropyl ether, benzoin isobutyl ether, benzoin tetrahydropyranyl ether and 2,2-dimethoxy-2-phenylaceto-phenone. A third class of photoinitiators is exemplified by diethoxyacetophenone and 2,2-dimethoxy-2-phenylaceto-phenone. The photoinitiator or mixtures thereof areusually added in an amount ranging from 0.0005 to 30% by weight of the ethylenically unsaturated compound.
A class of actinic light useful herein for curing is ultraviolet light and other forms of actinic radiat on which are normally found in radiation emitted from the sun or from artificial sources such as Type RS Sunlamps, carbon arc lamps 9 xenon arc lamps, mercury vapor lamps, tungsten halide lamps and the like. Curing periods may be adjusted to be very short and hence commercially economical by proper choice of ultraviolet source, pho~oinitiator and concentration thereof, temperature and molecular weight and reactive group functionality of the ethylenically unsaturated compound. W curing periods of about l to 5 seconds duration are possible; for example, in coatings, adhesives and encapsulants.
When W radiation is used, an intensity of 0.0004 to 60.0 watts/cm in the 200-400 nanometer region is usually employed.
The heating step requires heating the reactants to at ~5 least 80C, preferably in the range 80-200C, for periods ranging from lO seconds to 30 minutes, in order to form the fully cured product.
In practicing the instant invention the dual UV/heat curable composition is admixed in any order and applied to the substrate by various conventional means~ Following application the compasi~ion is exposed to UV radiation for a short period of time, e. g., about l second to l minute, andt thereafter, exposed to heat by, e. g~, passage through a conventional heating oven for a time sufficient 5 to fully cure the composition to a solid product.

The following examples will aid to explain, butspecifically not limit7 the instant inven~ion. unless otherwise noted, all parts and percentages are by weightO
Strength properties of adhesion in shear by tension loading were measured in accord with the procedure set o~t in ASTM D-1002 72.
Exam~e 1 The following master batche~ were prepared:

Master Batch (11-Components Parts Trimethylolpropane trimethacrylate 4 nparaplex" G-54 8 * ~
"Lupersol" 231' 0.2 ~Darocur n 117 3 0 . 2 1) Adipate polyester plasticizer, mol wt 3,000, sp.
gravity 1.08, acid number (mg KO~/g) 1.1, saponification (mg KOH/g) 535, commercially available from Rohm & Haas;
2) A low fusing vinyl acetate-vinyl chloride copolymer dispersion resin, sp. gravity 1.37, sp~
viscosity 1~45 in 1~ eyclohexanone at 30C and K
value of 70, commercially available from Diamond Shamrock;
253) l,l-bis(t-butyl peroxy)-3,3,5-trimethylcyclo~
hexane, commercially available from Pennwalt.
4) 2-hydroxy-2-methyl-1-phenyl-propan-1-one, commercially available from Merck.

Master Batch (2L:
Components Parts Trimethyolpropa~e trimethacrylate 4 nparaplex" G-54 8 P~-7401 8 "Lupersol" 231 0O02 "Darocur n 1173 0 . 02 * Trademark - 18 -Master Batch (3) Components Parts Trimethylolpropane trimethacrylate 4 "Paraplex" G-54 B

"Darocur" 1173 Benzopinacol 0.2 Master Batch (4):
_ m~onents Parts Trimethylolpropane trimethacrylate 4 "Paraplex" G 54 8 "Darocur" 1173 0.2 15 Azobisisobutyronitrile 0.2 Master Batch (5 ?:
Components Parts Trimethylolpropane trimethacrylate 4 20 "Paraplex" G-54 8 PVC-7~01 8 "Darocur" 1173 0.2 Tetramethylthiuram di~ulfide5 0.02 5) Recrystallized from boiling chloroform.
Master Batch (6):
C ponents Parts Trimethylolpropane trimethacrylate 4 30 "Paraplex~ G-54 8 "Pliovic'l WO-26 8 ~Darocur Dl 1173 0.2 "Lupersola 231 0.2

6) A vinyl chloride dispersion resin, commercially available from Goodyear Chemical.

3~

Master Batch (7~:
Components Part_ Trimethylolpropane trimethacrylate ~Paraplex" G-54 nLupersol" 231 002 YIrgacure" 6517 Q.2

7) 2,2-dimethoxy-2 phenyl acetoph none~ commercially available from Ciba-Geigy.
Master Batch (8):
. .
Components Par t s 1,6-Hexanediol diacrylate 4 "Paraplex~ G-54 8 "Lupersol" 231 0.2 "Darocur~ 1173 0.2 Master Batch (9):
Components Parts Trimethylolpropane trimethacrylate 2 ~iisononylphthalate 3 "Plex"-4858 F 0-7 Benzoyl peroxide 0.1 "Darocur n 1173 0 .1

8) Terpolymer of 86 parts polymethyl methacrylate, 12 parts polybutyl methacrylate and 2 p~rts vinyl imidazole, commercially available from Rohm, Darmstadt~ West Germany.

* Trademark Master Batch (10):
Components Parts Trimethylolpropane trimethacrylate 3 1,4-butanediol diglycidyl ether 3 PVCo74~1 4 "Darocur" 1173 0~1 nLeepoxy" B-550 0.1

9) An amine BF3 adduct, commercially available from Leepoxy Plastics.
Master Batch (11):
Components Parts Trimethylolpropane trimethacrylate 4 "Lupersol~-231 0.12 nDarOcur n 1173 0.12 Master Batch (12~:
Compone~ts Parts 20 1,4-butanediol diglycidyl ether 4 Diphenyl-4-thiophenoxyphenylsulfonium hexa-fluorophosphate 0.12 ~Leepoxy" B-550 0.112 "Plexn-4858 ~ 3 The master batches were each made up by combining all the ingredients and stirring until a smooth homogeneous mixture was obtained. The mixture was then deaerated by vacuum .
The following examples will show the ability of the above formulations to provide a skin cure to prevent sagging by use of W radiation alone.

* Trademark Exam~le 2 Master batch ~1) was drawn down on glass substrates to thicknesses of 5, 10 and 30 mils~ The coatings wer~
then exposed to W radiation from an ~ddalux medium pressure Hg lamp for 1 second. In each instance a skin cure sufficient to hold the coating in place was obtained. The coated substrates were then heated at 140C
in an oven for 25 minutes. ~ solid, cured coating was obtained in all thicknesses.
Example 3 Example 2 was repeated except that master batch (2~
from Example 1 wa~ employed and the radiation exposure was 4 seconds. At all thicknesses after heatingl a cured, solid coating was obtained.
Exa~
A 1/8" thick line of master batch ~1) from Example 1 was placed on the overlap of 2 pieces of metal. 2 sampl~s were made up~ One of the samples was subjected to W
radiation from an Addalux medium pressure mercury lamp for a 6-second exposure. The 2 samples were then placed under a forceful stream of water to see if any wash-off ~ecurred. The test sample which had not been subjected to W radiation had a complete wash-off of the line of master batch (1) in less than 1 secondO The test samples with the 6-second W exposure had no wash-off after 6 seconds under the water stream. Wash-off resistance was due to the skin cure covering the lineO The UV exposed sample was then heated at 120C in an oven for 30 minutes. This resulted in a solid adhesive line holding the metal pieces together for each sample.
Example 5 A 1.5" X 2.125" circuit board containing electronic components was completely coated on all sides with an 80 mil thick encapsulating coating of master batch (1) from Example 1 by dipping. The thus coat~d circuit board was exposed for 6 seconds to UV radiation on all sides from an Addalux medium pressure Hg lamp to sbtain a tack-free, thick skin cure. The board was then heated in an oven at 120C at 30 minutes. The coating was a hard, tack-free solid after heating, and the board and components on the board were completely encapsulated.
Example 6 Master batches (3), ~4), (5) and (6~ from Example 1 were each applied to glass substrates in a thickness of 30 mils. The thus coated substrates were then exposed for 4 seconds to an Addalux medium pressure Hg lamp to give a coating with a skin cure. All the substrates were heated ~ C in an oven for 20 minutes. All the resultant 1:; coatings were tack-free solids after heating.
Example 7 Master batch (7) from Example 1 was coated on a glass substrate at a thickness of 30 mils. The coating was then exposed to W radiation for 2 seconds from an Addalux medium pressure Hg lamp. The thus irradiated coating had a skin cure. Heated in the skin cured coating in an oven at 140C for 20 minutes resulted in a completely cured solid.
Example 8 Master batch (8) from Example 1 was coated on glass substrates to a thickness of 30 mils. The coating was then exposed to W radiation for 2 seconds from an Addalux medium pressure Hg lamp. The thus exposed coating was cured on the surface. The thus irradiated coating was then heated in an oven at 140C for 20 minutes resulting in a completely cured, tack-free solid.
Example 9 Example 5 was repeated except that Master Batch (2) from Example 1 was used. The coating was a hard, tack-free solid after UV radiation and heating at 120C
for 30 minutes~ The components on the board were completely coated after heatingO
Example 10 Master Batch ~10) from Example 1 was drawn down on glass substrates at a thickness of 30 mils. The composition was then exposed at a distance of 24" to UV
radiation from an Addalux medium pressure Hg lamp for 2 seconds. The coating had a skin cure sufficient to hold the coating in place. The coated substrates were then heated at 140C in an oven for 30 minutes. A solid, cured, transparent coating was obtained.
Example 11 Master Batch (9) from Example 1 was drawn down on glass substrates at a thickness of 30 mils. The composition was then exposed to UV radiation from an ~ddalux lamp, 24" away, for 5 seconds, to give a skin curer The coated substrate was then heated in an oven at 80C for 30 minutes resulting in a tack-free, solid coating.
Example 12 Master Batch (11) from Example 1 was drawn down on glass substrates at thicknesses of 10 and 30 milsO The compositions were then exposed at a distance of 24" to W
radiation from an ~ddalux medium pressure Hg lamp for 2 seconds resulting in a a skin cure. The coated substrates were then heated at 140C in an oven for 20 minutes resulting in so]id~ tack-free coatings in both thicknesses.
Example 13 Master Batch (2) from Example 1 was applied as 1/2", 20 mil-thick lap on as received cold-roll steel and a fiberglass and polyester composite (SMC)~ commerci~lly available from Budd Co. The thus coated substrates were exposed to UV radiation from an Addalux medium pressure Hg lamp for 3 seconds to form a skin cure. The thus coated substrate was then clamped together with an uncoated substrate of the same material and heated at 140C in an oven for 20 minu~es. The samples were then measured for impact strength and lap shear strength of the adhesiveO
The adhesive between the steel substrates failed in the adhesive with an impact strength of 1~ in~-lb./0.5 in.2 and an average lap shear strength of 906 psi. over an average of 5 samples~ The adhesive on the SMC ~ubstrate failed in the substrate with an average impact strength of 29 in.-lb./0.5 inO2 and an average lap shear strength of 848 psi. over an average of 5 samples.
Example 14 Preparation of Di~henyl-4-thiophenoxyphenylsulfonium Hexafluorophosphate 3~15 g of commercially available potassium hexafluorophosphate was added to 150 ml of water. To another container 10 9 of a 50~ aqueous solution of ~i~henyl-4-thiophenoxyphenylsulfonium chloride was added to 40 ml of water. This second solution was poured into the first solution with stirring. The resulting white solid product was collected, washed with water and then ether, followed by vacuum drying at 60C overnight.
6.1 9 of this material was dissolved in a mixture of 1 liter of 95% ethanol and 200 ml acetone by boiling. The liquid was reduced to half i s volume by bubbling nitrogen through while heating. The remaining liquid containing crystalline product was refrigerated and, thereafter, the pale, yellow-white crystals were collected and washed with ethanol. On drying 3.7 9 of solid diphenyl-4-thiophenoxy-phenylsulfonium hexafluorophosphate was obtainedO

~ 2~ -;3~

Example 15 Master batch ~12) was drawn down on glass substrates to thicknesses of 5~ 10 and 30 mils. The coatings were then exposed to W radiation from an Addalux medium pressure Hg lamp for 20 seconds. In each instance a skin cure sufficient to hold the coating in place was obtained. The coated substrates were then heated at 140C
in an oven for 25 minutes. An elastic solid, tough, cured coating was obtained in all thicknesses.
~xample 16 A 1/4" thick line of master batch ~1) from ~xample 1 was placed as a sealant on the line of intersection of 2 pieces of metal perpendicular to e~ch other. The sealant line was exposed to W radiation from an Addalux ~e~ium pressure Hg lamp for 3 seconds. A skin cure sufficient to hold the sealant in place and the metal pie~es perpendicular to each other resulted. The assembly was then heated at 140C in an oven for 25 minutes. A
solid, cured sealant line resulted.

Claims

I CLAIM:

1. A UV and thermally curable composition comprising (1) a liquid, ethylenically unsaturated monomer, oligomer or prepolymer of the formula:

wherein R is H or CH3, R1 is an organic moiety and n is at least 2, (2) a thermal initiator for (1) selected from the group consisting of substituted or unsubstituted pinacols, azo compounds, thiurams, organic peroxides and mixtures thereof, (3) a photoinitiator for (1) selected from the group consisting of aldehyde and ketone carbonyl compounds having at least one aromatic nucleus attached directly to the group, benzoin alkyl ethers, diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone, (4) a thermoplastic material, and (5) a non-polymerizable plasticizer for (4).

2. The composition of Claim 1 wherein (2) is an organic peroxide, (3) is 2-hydroxy-2-methyl-1-phenyl-propan-1-one, (4) is polyvinyl chloride and (5) is an adipate polyester plasticizer.

3. The composition of Claim 1 wherein (2) is an organic peroxide, (3) is 2-hydroxy-2-methyl-1-phenyl-propan-1-one, (4) is a vinyl acetate-vinyl chloride copolymer and (5) is an adipate polyester plasticizer.

4. The composition of Claim 1 wherein (2) is an organic peroxide, (3) is 2-hydroxy-2-methyl-1-phenyl-propan-1-one, (4) is a methyl methacrylate, butyl methacrylate and vinyl imidazole terpolymer and (5) is diisononylphthalate.

5. The process of forming a cured product which comprises admixing a UV and thermally curable composition comprising (1) a liquid, ethylenically unsaturated monomer, oligomer or prepolymer of the formula:

wherein R is H or CH3, R1 is an organic moiety and n is at least 2, (2) a thermal initiator for (1) selected from the group consisting of substituted or unsubstituted pinacols, azo compounds, thiurams, organic peroxides and mixtures thereof, (3) a photoinitiator for (1) selected from the group consisting of aldehyde and ketone carbonyl compounds having at least one aromatic nucleus attached directly to the group, benzoin alkyl ethers, diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone, (4) a thermoplastic material, and (5) a non-polymerizable plasticizer for (4), exposing said composition under atmospheric conditions to UV radiation having an intensity in the range 0.0004 to 60.0 watts/cm in the 200-400 nanometer region and, thereafter, heating the composition to a temperature in the range 80-200°C for a time sufficient to obtain a fully cured solid, tack-free product.

6. The product obtained by the process of Claim 5.

7. The process of forming a cured coating on a substrate which comprises applying to a substrate a W and thermally curable composition comprising (1) a liquid, ethylenically unsaturated monomer, oligomer or prepolymer of the formula:
wherein R is H or CH3, R1 is an organic moiety and n is at least 2, (2) a thermal initiator for (1) selected from the group consisting of substituted or unsubstituted pinacols, azo compounds, thiurams, organic peroxides and mixtures thereof, (3) a photoinitiator for (1) selected from the group consisting of aldehyde and ketone carbonyl compounds having at least one aromatic nucleus attached directly to the group, benzoin alkyl ethers diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone, (4) a thermoplastic material, and (5) a non-polymerizable plasticizer for (4), exposing said composition under atmospheric conditions to UV radiation having an intensity in the range 0.0004 to 60.0 watts/cm in the 200-400 nanometer region and, thereafter, heating the composition to a temperature in the range 80-200°C for a time sufficient to obtain a cured solid, tack-free product.

8. A process for adhering two substrates which comprises applying to at least one of said substrates an adhesive composition comprising (1) a liquid, ethylenically unsaturated monomer, oligomer or prepolymer of the formula:
wherein R is H or CH3, R1 is an organic moiety and n is at least 2, (2) a thermal initiator for (1) selected from the group consisting of substituted or unsubstituted pinacols, azo compounds, thiurams, organic peroxides and mixtures thereof, (3) a photoinitiator for (1) selected from the group consisting of aldehyde and ketone carbonyl compounds having at least one aromatic nucleus attached directly to the group, benzoin alkyl ethers, diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone, (4) a thermoplastic material, and (5) a non-polymerizable plasticizer for (4), exposing said composition under atmospheric conditions to UV radiation having an intensity in the range 0.0004 to 60.0 watts/cm2 in the 200-400 nanometer region for a time sufficient to partially cure the adhesive in situ, contacting the substrates with the partially cured adhesive therebetween and, thereafter, heating the composition to a temperature in the range 80-200°C for a time sufficient to obtain a fully cured solid adhesive.

9. A process for sealing two substrates which comprises contacting said substrates, applying to the substrates at a line of contact a sealant composition comprising (1) a liquid, ethylenically unsaturated monomer, oligomer or prepolymer of the formula:

wherein R is H or CH3, R1 is an organic moiety and n is at least 2, (2) a thermal initiator for (1) selected from the group consisting of substituted or unsubstituted pinacols, azo compounds, thiurams, organic peroxides and mixtures thereof, (3) a photoinitiator for (1) selected from the group consisting of aldehyde and ketone carbonyl compounds having at least one aromatic nucleus attached directly to the group, benzoin alkyl ethers, diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone, (4) a thermoplastic material, and (5) a non-polymerizable plasticizer for (4), exposing said composition under atmospheric conditions to UV radiation having an intensity in the range 0.0004 to 60.0 watts/cm2 in the 200-400 nanometer region to obtain a tack-free skin cure of the sealant composition and, thereafter, heating the composition to a temperature in the range 80-200°C for a time sufficient to obtain a fully cured solid sealant.

10. A process for encapsulating an article which comprises coating said article with a UV and thermally curable composition comprising (1) a liquid, ethylenically unsaturated monomer, oligomer or prepolymer of the formula:
wherein R is H or CH3, R1 is an organic moiety and n is at least 2, (2) a thermal initiator for (1) selected from the group consisting of substituted or unsubstituted pinacols, azo compounds, thiurams, organic peroxides and mixtures thereof, (3) a photoinitiator for (1) selected from the group consisting of aldehyde and ketone carbonyl compounds having at least one aromatic nucleus attached directly to the group, benzoin alkyl ethers, diethoxyacetophenone and 2,2-dimethoxy-2-phenylacetophenone, (4) a thermoplastic material, and (5) a non polymerizable plasticizer for (4), exposing said composition under atmospheric conditions to UV radiation having an intensity in the range 0.0004 to 60.0 watts/cm in the 200-400 nanometer region to obtain a tack-free partial cure of said coating sufficient to hold it in situ and, thereafter, heating the composition to a temperature in the range 80-200°C for a time sufficient to obtain a fully cured, tack-free solid encapsulating coating.

~ '