CA1136340A - Hydroxyl-containing compositions and their polymerisation - Google Patents

Abstract

Abstract of the Disclosure Polymerisable compositions comprise a) a compound containing in the same molecule both at least one phenolic hydroxyl group and at least two groups chosen from allyl, methallyl, and 1-propenyl groups, e.g., 2,2-bis(3-allyl-4-hydroxy-phenyl)propane of bis(3-(1-propenyl)-4-hydroxyphenyl)methane, b) a compound containing at least two mercaptan groups per molecule, e.g., pentaerythritol tetrathioglycollate, and c) a heat-activated crosslinking agent for phenol-aldehyde novolac resins.
The compositions are caused to polymerise by the action of irradiation or free-radical catalysts. The polymers so obtained, containing more than one phenolic hydroxyl group, can be subsequently crosslinked in situ by heating. The compositions are useful in various two-stage operations, such as the production of multilayer printed circuits.

Description

~L11 3634(3 T~IS INVE~TION relates to compositions containing a polymercaptan and a compound which has both at least two allyl, methallyl, or l-propenyl groups and at least one phenolic hydroxyl group. It also relates to the polymerisation of such compositions by means of actinic radiation or free-radical catalysts, to the further crosslinking, on heating, of polymerised products, alone or with a heat-curing agent, and to the use of such products as surface coatings, in printing plates, printed circuits, and reinforced compos;tes, and as adhesives.
For a number of reasons it has hecome desirahle to induce polymer-isation of synthetic resin composîtions by means of actinîc radiation. E~ploying photopolymerisation procedures may, for example, avoid the use of organic solvents wî~h their attendant risks of toxicity, flammability, and pollution, and the cost o recovering the solvent. Photopolymerisation enables insolu~ilisation of the resin composition to be restricted to defined areas, i.e., t~ose which have been irradiated, and so permits the production of pr;nted circuits and printing plates or allows the hondîng of substrates to be confined to required zones. Further, in production processes, irradiation procetures are often more rapid than those involvîng heating and a consequential cooling process.
We have now found that valuable products can be made by photo-polymerisation of compositions containing a polymercaptan and a compound which contains both at least one phenolic ~ydroxyl group and at least two allyl, and/or methallyl, andlor l-propenyl groups.
We have found, too, that such compositions may also be polymerised by means of free-radical catalysts. The composition, comprisîng polymerised material containing residual phenolic hydroxyl groups, - , ~

3L~L3~3~a~

may be further crosslinked, i.e., converted into the insolubleJ infusible, C-stage, on heating by means of a heat-activated cross-linking agent for phenol-aldehyde novolac resins containecl therein. Hence, a stepwise cure is possible.
One aspect of this invention accordingly provides polymerisable compositions comprising a~ a compound containing in the same molecule both at least one phenolic hydroxyl group and at least two groups chosen from allyl, methallyl, and l-propenyl groups, b) a compound containing at least two mercaptan groups per molecule, such that a) provides a total of from 0.4 to 2.4 equivalents selected from allyl, methallyl, and l-propenyl group equivalents per mercaptan group equi-valent in b), and c) a heat-activated crosslinking agent for phenol-aldehyde novolac resins.
Another aspect of this invention is a process for the polymerisation of such compositions, comprising exposing them to actinic radiation or to the effect of a free-radical catalyst.
We have further found that mixtures of a compound having at least two phenolic hydroxyl groups and at least two allyl, methallyl, or l-propenyl groups with a compound having a mercaptan functionality greater than two can be cured on irradiation or on heating in the presence of a free-radical catalyst to form crosslinked polymeric coatings having excellent adhesion to polar substrates such as metals and glass.
Hence there are also provided polymerisable compositions comprising d) a compound containing in the same molecule both at least two phenolic hydroxyl groups and at least two groups chosen from allyl, methallyl, and l-propenyl groups, and r~

:~ . ~ . : , -'~-, - : ':

' ~ ~ ': ~ " , ' "'.. ' ' ', 1~3~i34~) e) a compound having at least three ~ercaptan groups per molecule, and a process for the polymerisation of such compositions, comprising exposing them to actinic radiation or heating them in the presence of a free-radical catalyst.
It is known that compounds containing allyl groups undergo an addition reaction with polymercaptans, which reaction may be initiated by actinic radiation or by free-radical catalysts t see, e.g., British Patent Specifications No. 1 215 591, 1 251 232, 1 292 722, 1 445 814, and United States Patent Specifications Nos. 3 787 303, 3 877 971, 3 900 594, and 3 908 039). There has been described, for example, such a reaction between compounds containin~ two, three, or more mercaptan groups and diallyl adipate, 2,2-bis(4-allyloxyphenyl)-propane, 2,4,6-tris(allyloxy)-s-triazine, 2,2-bi~(4-(3-diallylamino-

2-hydroxypropoxy)phenyl)propane, and di-adducts of allyl alcohol, diallyl malate, or trimethylolpropane diallyl ether with toluylene-2, 4- or -2,6-di-i~ocyanate, 3,3~~dimethyl-4,4'-di-isocyanatodiphenyl, ; 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, or 4,4'-methylenebis(cyclohe~yl-isocyanate). When the sum of the number of allyl groups per average mole~ule of the allyl component and of the number of mercaptan groups per average molecule of the polymercaptan is more tha~ 4, crosslinked structures may be formed. Further, Marvel and co-workers (J.Polymer Sci., 1951, 6, 127-143 and ibid, 711-716) have described the reaction of hexane-1,6-dithiol with 2,6-diallylphenol under the influence of ultra-violet light or a 25 free radical catalyst. The resultant polymer, of low intrinsic viscosity, was converted into a crosslinked rubber by mixing it with hexamethylenetetramine and then ~, . . : . .
,,,. . :. ....

~3~;3~L() heating. However, the addition of polymercaptans across the double bonds of allyl, methallyl, or l-propenyl groups in cQmpounds containing at least one phenolic hydroxyl group in the presence of a heat-activated crosslin~in~ agent for phenol-aldehyde novolac resins to form products which can be subsequently crosslinked in s~tu by heating, has not, it is believed, hitherto been described. Neither, it i5 believed, has the crosslinking of at least dihydric phenols containing two or more allyl, matballyl,or l-propenyl groups by means of tri- and higher mercaptans been described.
Preferably the component a) or d) contai~s one or more benzene nuclei or one or more naphthalene nuclei as the sole aromatic constituents, and preferably it has a molecular weight of at most 1000.
Preferably each allyl, methallyl, or l-propenyl group is directly attached to an oxygen, nitrogen, or carbon a~om, particularly either to a carbon ato~ which forms part o an aromatic nucleus or to an oxygen atom which in turn is directly attached to a carbon atom which forms part of an aromatic nucleus. Especially preferred as components a) or d) are polynydric phenols, the phenolic hydroxyl groups of ~hich are partially etherified with allyl, methallyl, or l-propehyl groups,~or phenols substituted in the aromatic nucleus or nuclei by allyl, methallyl, or } propenyl groups, especially by an allyl, methallyl, or l-propenyl group ortho to each phenolic hydroxyl group.
The following formulae are those of examples of preferred compounds:

Rl ~ ~ I I

:. ,, :; ;,:

. .

~L~3~

OH

Rl ~3 Rl II

0~

Rl '~ Rl IIr 0~

Rl``~ ~ Rl rv 2 i ~ CR2 t~R V

oR4oR4 oR4 ~} ~52 ~ 23~ vr e~ R -~O~ VIr Rl 1 1~3~i3~V

and, as a component a~, OH
Rl ~ Rl VIII

~ 3 where R denotes a carbon-carbon hond, an alkylene group of 1 to 5 carbon atoms, an ether oxygen ato~, a sulp~ur atom, or a group of Eormula -CO^, -SS-, -SO , or -S02-, l denotes an allyl, methallyl, or l-propenyl group, a is an integer of at least 1 in the case of component a2 and a~
least 2 in the case of a component d~, 10 each R denotes an allyl or methallyl group, each R3 denotes a hydrogen, chlorine, or bromine atom, or an alkyl group of 1 to 4 carbon atoms, and each R4 denotes an allyl or methallyl group or a hydrogen atom, such that at least t~o R4 each denote an allyl or methallyl group and in the case of a componen~ a) at leas~ one R4 de~otes a hydrogen atom and in the case of a component d), at least two R4 each denote a hydrogen atom, with the proviso that, in formulae V and VI, the -CH2- groups shown are ortho-_ or æara- to the indicated groups -OH, -oR2, and -oR4.
Particularly preferred are 2,2-bis(3-allyl-4~hydroxyphenyl)propane, bis(3-allyl-4-hydroxyphenyl)methane, and their 3-(1-propenyl) analogues.
Compounds oE formulae I to V are obtainable by conversion of the corresponding unsubstitu~ed phenols, i.e., those of formula IX

' .

, : . , , : : . ~ ~ :

, . ~ : , :. i:
' ~

i3~

HO ~ R ~ oa I~ -hydroquinone, 1,5- or 1,8-dihydro~y~laphthalene, and a novolac of ormula X
' .
; OH - OH - 0 ~ 2 ~ ~2 S where R, R3, and a have the meanings previously assigned, and the -CH
groups shown are ortho- or para- to the indicated -OH groups, into their at least diallyl and dimethallyl ethers, e.g., by means of allyl or methallyl chloride, Claisen rearrangement to the ortho-allylphenol or ortho-methallylphenol, and,optionally, isomerisation of the ortho-allylphenol into the ortho-l-propenylphenol by heating in the presence of a strong alkali.
Compounds of formula VI are obtainable by par~ial etherification using, e.g., allyl chloride or methallyl chloride, of residual phenolic hydroxyl groups in novolacs of formula X. Compounds containing two allyl, methallyl, or l-propenyl groups in the sa~e phenolic nuc~leus, such as those of formula VII and VIII, are ofitainable fiy etherification with, e.g., allyl chlorîde or ~ethallyl chloride9 of the ortho-allyl or ortho -methallyl phenol, followed by a second Claisen rearrangement and, optionally, isomerisation of allyl groups to l-propenyl groups through the act:ion of alkali.
There may also be used as co~ponent a2 or d~ a product obtained ,: .
j, ~13Si3~

by advancement of a stoichiometric deficit of a diepoxide with a dihydric phenol substituted in the aromatic nucleus or nuclei by at least one allyl, methallyl~ or l-propenyl group, e.g., a phenol of formula I or II. Suitable diepoxides include diglycidyl ethers of dihydric alcohols, di~lycidyl esters of dicarboxylic acids, di-(N-glycidyl)hydantoins, such as 1,3-diglycidylhydantoin and 3,3'-diglycidyl-l,l'-methylenebis(hydantoin), and diglycidyl ethers of dihydric phenols, e.g., of a dihydric phenol of formula IX. Alter-natively~ there may be used as component a3 or d) a product obtained by advancement with a dihydric phenol, a dihydric alcohol, a dicarboxylic acid, or a hydantoin containing t~o N~ groups, of a diepoxide containing at least one allyl, me~lyl, or l-propenyl group, such as the diglycidyl ether of a phenol of formula I.
The ad~ancement of diepoxides is a generally known reaction (see, 15 e.g., H. Batzer and S.A~ Zahir, J. Appl. Polymer Sci., 1975, 19, 585-600 and H. Lid~ri~ ~unststoff Rundschau, 1959, 4, 6-10) and can be used to prepare allyl-, methallyl-, and l-propenyl-containing phenols of the type used in this invPntion.
; A wide range of polymercap~ans is suitable for use as component b) or e) in the composi~ions of this invention. Preferably the mercaptans are free from any allyl, methallyl, l-propenyl, or phenolic hydroxyl group, and preferably they have a molecular weight of not more than 3,000. The polymercaptans employed generally contain not more than six mercaptan groups per molecule.
One class comprises esters of monomercaptancarboxylic acids with polyhydric alcohols or of monomercaptanmonohydric alcohols with ; polycarboxylic acids.
'.: ,:, ~3~

Further preferred such esters are of the for~ula , OH ~
c(e) R5 ~ (CO)dO(CO)e:R6SH ~ XI
\ b - c(d) where R5 represents an aliphatic or araliphatic hydrocarbon radical of from 2 to60 carbon atoms, which may contai7l not more than one ether oxygen atom, R6 represents a hydrocarbon radical, which may contain not more than one carbonyloxy group, and is preferably of from l to 4 carbon : atoms, b is an integer of from 2 to 6 in the case of a component b) or of from 3 to 6 in the case of a compo~ent e), c is zero or a positive i7nteger of at most 3, such that (b + c) is at most 6 ( terms such as c(d) being construed algebraically), and d and e each represent zero or l, but are 7ao~ t7ne same.
Yet further preferred esters are polymercaptans of formula XI
:~ which are also of the formula . R7~oC~R8S~)b XII
;; where D has the meaning previously assigned, R7 is an aliphatic hydrocarbon radical of from 2 to lO carbon atoms, and .~ , . . - .

, :. - ~ .~ '' " ~

1~3~;3~

R denotes -C~2)2-9 -(CH2)2, or -CH~C~3)-.
Also preferred are mercaptan-containing esters, including esters of monomercaptandicarboxylic acids, of formula XIII

Rll ~ ()d ~ C()e - - R9(0)e - C()d ~ R OSH ]
where d and e have the meaning previously assigned, f is an integer of from 1 to 6 in the case of a component b) or of from 2 to 6 in the case of a component e), R9 represents a divalent organic radical, linked through a carbon atom or carbon atoms thereof to the indicated -0- or -C0- units, R10 represents a divalent organic radical, linked through a carbon atom or carbon atoms thereof to the indicated -SH group and -0- or -C0- unit, and Rll represents an organic radical, which ~ust contain at least one 15 -SH group either in ~he case of a component b) when f is 1, : or in the case of a component c) when f is 2, linked through a carbon atom or carbon atoms thereof to the indicated adjacent -0-or -C0- unit or units.
Preferably, R9 denotes, when d is zero, a saturated aliphatic unbranched hydrocarbon chain of 2 to 20 carbon atoms, which may be substi~uted by one or more methyl groups and by one or more mercaptan groups and which may be interrupted by one or more ether oxygen atoms and by one or more carbonyloxy groups; when d is 1, R9 preferably denotes (i) a saturated aliphatic hydrocarbon group of 2 to 10 carbon atoms, which may bear a mercaptan group, ~ - ~ ;: "

3L13~3~C~

(ii) a cycloaliphatic-aliphatic hydrocarbon group of 5 to 34 carbon atoms, which may contain one or more ethylenically-unsaturated double bonds 9 or (iii) a mononuclear arylene hydrocarbon group of 6 to 12 carbon atoms.
R10 preferably denotes, when d is zero, a saturated aliphatic hydrocarbon group of 1 to 3 carbon atoms, which may bear a carboxyl group, and, when d is 1, it preferably denotes a saturated aliphatic hydrocarbon group of 2 to 4 carbon atoms, which may be substituted by a hydroxyl group or by a chlorine atom.
Rll preferably denotes ~ iv) an aliphatic or cycloaliphatic-aliphatic hydrocarbon group of 2 to 51 carbon atoms, which may bear at least one mercaptan group, or (v) a mononuclear or dinuclear arylene hydrocarbon group of 6 to 15 carbon atoms, or (vi) a chain o 4 to 20 carbon atoms, interrupted by at least one ether oxygen atom and optionally substituted by at least one mercaptan group, or (vii) a chain of 6 to 50 carbon atoms, interrupted by at least one ; carbonyloxy group, optionally interrupted by at least one ether oxygen atom, and optionally substituted by at least one mercaptan group.
Also suitable are esters and ethers ~hich are of the general formula r R12 ~ (o R13) OH ~

g )h k .~ - , . . ~

~L3634~

where R12 represents a r~dical of a polyhydric alcohol after remo~al of (i ~ k) alcoholic hydroxyl groups, especially an aliphatic hydrocarbon radical of fr~m 2 to 10 carbon atoms, each R13 denotes an alkylene group containing a chain of at least 2 and at most 6 carbon atoms between consecutive oxygen atoms, 8 is a positive integer, preferably such that the averags molecular weight of the polymercaptan is not more than 2,000, h is zero or 1, -i is zero or a positive integer such that (i + k) is at most 6, k is an integer of from 2 to 6 in the case of a component b) and an integer of from 3 to 6 in the case of component e), and Rl4 represents an aliphatic radical of 1 to 6 carbon atoms containing at least one mercaptan group.
The groups R13 in individual poly(oxyalkylene) chains may be the same or different and they may be substituted by, e.g., phenyl or chloromethyl groups. Preferably they are -C2H4- or C3H6- groups.
Preferred amongst the compounds of ormu1a ~IV are the esters of formula _ _ R7 ~ (O R13) OH i ~ (O-R )gOCOCmH2mSH
and ethers of formula --E ( R13) o~l (O-R )gOCa2CHCH2SH ~ XVI
0~1 :

.

~3~i3~

where R7, R13, ~ i, and k have the meanings previously assigned and m is 1 or 2.
Yet other polymercaptans, suitable as component b), are mercaptan-terminated sulphides of the general formula f P~ R ~ R rSS ~ R (O)p ~ CH0 ~ R15 SH

where each R15 denotes an alkylene hydrocarbon group containing from 2 to 4 carbon atoms, R16 denotes -H, -~3, os -C2H5~
n is an integer which has an average value of at least 1, and is preferably such that the average molecular weight of the sulphide is at most 1000, and either ~ is zero, in which case q and r are each also zero, or p is 1, in which case q is zero or 1 and r is 1.
The preferred sulphides of formula XVII are those where R16 denotes hydrogen and ~ and q are each 1, n being such that the molecular weight of the sulphide is from 500 to 800.
Another class of polymercaptans suitable as compo~ent b) comprises mercaptan-terminated poly(butadienes) of the formula : ' .

{ ~ C~2 C = b c~ _ ~ cl 2 ~ 5~

' ' . . ' ' ' .

~IL3~3~

where each R17 represents -H or CH3, -~
Rl~ represents -CN, -COOH, -CON~2, -COORl9, -C6H" or -oCoR19, where Rl9 is an alkyl group of one to eight carbon atoms, t is an integer of at least one, u is zero or a positive integer, and s is an integer of more than one, preferably such that the average number molecular weight of the polymercaptan is not more than 1000.
Preferably the polymercaptans of formula ~VIII are also of the formula H~ C~ - C~C~2 ~ ~ C~ca ~ ~ ~ XI~

where v is either zero, in which case w is 1, or it is 1, in which case w is an integer of from 2 to 5, and s has the meaning previously assigned.
Yet another suitable class of polymercaptan for use as component b) co~prises the mercaptan-terminated oxyalkylene compounds of the general formula HS--- CEIC}~20 ---- CHC~2S~
where each R17 has the meaning previously assigned and x is an integer of from 1 to 4.

...

.

.

~3~3~

A still further class comprises poly(thioglycollates) and poly(mercap~opropionates) of tris(2.-hydroxyethyl) isocyanurate-and tris(2-hydroxypropyl) isocyanurate~ i.e., the compounds of formula /\
CO CO
R200CHC~2N NCH2OEIOCOR8SH
117 \ C0 ~ 117 where each R8 and R17 have the meanings previously assigned and R20 denotes a group -COR8S~- or, in the case of a component b), may alternatively represent a hydrogen atom.
Particularly preferred polymercaptans are poly(thioglycollates) and poly(2- or 3-mercaptopropionates) of aliphatic polyhydric alcohols of 2 to 6 carbon atom~.
The proportion of component a) to component b) in the present compositions may vary within wide limits but preferably is such that a) provides a total of from 0.4 to 2.4, and especially 0.8 to 1.2, equivalents selected from allyl,methallyI, and l-propenyl groups equivalents per mercapta~ group equivalent in b). The proportions of component d) to component e) may likewise vary within wide limits but is preferably such that d) provides a to~al of from 0.4 to 2.49 especially 0.8 to 1.2, allyl and/or methaIlyl and/or l-propen71 group equivalents per marcaptan group equivalent in component e).
In photopolymerising the compositions of this invention, actinic radiation of wavelength 200-600 ~ is preferably used. Suitable , ~3f~340 sources of actinic radiation include carbon arcs, mercury vapour arcs, fluorescent lamps with phosphors emitting ultravi~let light, argon and xenon glow lamps, tungs~en lamps, and photographic flood lamps. Of these, mercury vapour arcs, particularly sun lamps, fluorescent sun lamps, and metal halide lamps are most suitable. The time required for the exposure of the photopolymerisable composition will depend upon a variety of factors which include, for example, the individual compounds used, the type of light source, and its distance from the irradiated composition~ Suitable times may be readily deter~
m~ned by those ~amiliar with photopolymerisation techniques, but when it is required that the products after photopolymerisation remain further crosslinkable by heating9 i.e., when a composition containing components a), b), and c) is.employed, polymerisation is carried out at a temperature below that at which thermal crosslinking through the phenolic hydroxyl groups becomes substantial.
; Preferably, for photopolymerisation, the composition contains a photoinitiator, i.e., a catalyst which, on irradiation, gives an excited state that leads to formation of free radicals which then initiate polymerisation of the composition. Examples of suitable - 20 photoinitiators are organic peroxides and hydroperoxides, ~ -halogen ; substituted acetophenones such as trichloromethyl 4'-tert.butylphenyl ketone, benzoin and its alkyl ethers ( e.g., the n-butyl ether), a~methylbenzoin, benzophenones such as benzophenone itself and 4,4'-bis(dimethylamino)benzophenone~ 0- alkoxycarbonyl derivatives of an oxime of benzil or of 1-phenylpropane-1,2-dione, such as benzil (0-ethoxycarbonyl)-~-monoxime and 1-phenylpropane-1,2-dione-2-C--ethoxYcarbonyl)oxime~ benzil acetals, e.g., its dimethyl acetal, ~ `.. --' ' , ,, , . : . .
., , . ;

~13~3~(3 - 18 ~
substituted thioxanthones, e.g., 2-chlorothioxanthone, anthraquinones, and photoredox systems comprising a mixture of a phenothiazine dye (e.g., methylene blue) or a quinoxaline ( e.g., a metal salt of 2-(m-or p-methoxyphenyl)quinoxaline-6'- or 7'-sulphonic acid) with an electron donor such as benzenesulphinic acid, or other sulphinic acid or a salt thereof such as the sodium salt, or an arsine, a phosphine, or thiourea.
Suitable photoinitiators are readily found by routine experiment-.ation. It is preferred that they do not give rise to a substantial degree of photoinduced polymerisation through consumption of phenolic hydroxyl groups, neither should any other substance present; it is further preferred that when a composition containing components a), b), and c) is employed, they do not cause crosslinking o~ the photo-polymerisable composition such that it does not remain substantially thermosettable.
Generally, 0.05 to 10%, and preferably 0.5 to 5%, by weight,of the photoinitiator is incorporated, based on the combined weights of the components a) and b) or d) and e).
The term "free-radical catalyst" is used herein to refer to substances and does not include actinic radiation. Suitable free-;~ radical catalysts for the polymerisation of the compositions of this invention include 2,2'-azobis(2-methylpropionitrile) and organic or inorganic peroxides, e g.; peracids and their salts and esters, such as peracetic acid, perbenzoic acid, perphthalic acid, di-;sopropyl peroxydicarbonate, ammonium or an alkali metal perborate, ammonium or an alkali me~al persulphatP9 acyl peroxides such as benzoyl peroxide, and also, e.g., cumyl peroxide9 cumene hydroperoxide, hydrogen peroxide, cyclohexanone peroxide, and ethyl methyl ketone ' ' ' ,, , peroxide. A tertiary amine, e.g., dimethylaniline, or a cobalt siccative, e.g., cobalt naphthenate, may be used as an accelerator with the peroxides.
The amount of free-radical catalyst, together with any accelerator therefor, is usually from 0.05 to 5%, and preferably 0.1 to 1%, by weight, calculated on the total of the weights of the components a) and b), or d) and e).
Standard methods of free radical catalyst-induced polymerisation can be employed; generally, it is necessary to apply heat, although if complete curing is not required, i.e., all the phenolic hydroxyl groups are not to be consumed, or all reactive sites are not to be occupied, because some further operation is intended, the maximum temperature to which the composition is subjected is limited accordingly.
As alxeady indicated, after the composition comprising components a), b), and c) has been polymerised, it may be further crosslinked by vir~ue of the phenolic hydroxyl groups present.
Another aspect of this invention thererore comprises a process for curing a polymerised composition comprising compone~ts a), b), and c) of this invention which comprises heating it.
Preferred heat-activated crosslinking agents c) include epoxide resins, the epoxide groups of which react with the phenolic hydroxyl groups.
In the usual methods of manufacturing epoxide resins, mix~ures of compounds of differing molecular weight are obtained, these mixtures ordinarily containing a proportion of compounds whose epoxide groups have undergone partial hydroylsis. The average number of l,~-epoxide , ~ . .
groups per molecule of the resin need not be an inte8er of at least : . : : ,.,.,: : . :: ::
:: .: , ~, ,:

i3~;~

2; it is generally a fractional number but must in any case be greater than 1Ø --Examples of resins which may be used are polyglycidyl andpoly(~-methylglycidyl) esters obtai~able by reaction of a substance containing two or more carboxylic acid ~roups with epichlorohydrin, glycerol dichlorohydri~, or 3-methylepichlorohydrin in the presence I of an alkali. Such esters may be derived from aliphatic carboxylic acids, e.g., oxalic acid, succinic acid, adipic acid, sebacic acid, ; and dimerised and trimerised linoleic acid, from cycloaliphatic carboxylic acids ~uch as hexahydrophthalic acid, 4-methylhexahydro-phthalic acid, tetrahydrophthalic acid, and 4-methyltetrahydro-; phthalic acid, and from aromatic carboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid.
- Other epoxide resins which may be used include polyglycidyl a~d ; poly(~-~ethylglycidyl) ethers, such as those obtainable by react~on of a substance containing at least two alcoholic hydroxyl groups or at least two phenolic hydro~yl groups with the appropriate epichlorohydrin or glycerol dichlorohydrin und~r alkaline conditions or, alternatively9 in the presence of an acidic catalyst with subsequent treat æ nt with alkali. Such ethers may be derived from aliphatic alcohols, for example, ethylene glycol, diethylene glycol, triethylene glycol, 2nd higher poly(oxyethylene) glycols, propylene glycol and poly(oxypropylene) glycols, propane-1,3-diol, butane-l,4-diol, pentsne-1,5-diol, hexane-1,6-diol, hexane-1,2,6-~riol, glycerol, l,l,l-trimethylolpropane, and pe~taerythritol; from cycloaliphatic alcohols such as quinitol, 1,1-bis(hydroxymethyl)cyclohex-3-ene, , ` ' ' ': ::
'' :' :

~3634~

bis(4-hydro~ycyclohexyl)methane, and 2,2-bis(4-hydroxycyclohexyl)-propane; and from alcohols containing aromatic nuclei, such as N,N-bis(2-hydroxyethyl)aniline and 4,4-bis(2-hytroxyethylamino)-diphenylmethane. Preferably the et:hers are poly~lycidyl ethers of an at least dihydric phenol, for e~ample, resorcinol, catechol, hydroquinoue, bis(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxy-; phenyl)ethane, 4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl) sulphone, and phenol-~ormaldehyde, alkylphenol-formaldehyde, a~d chlorophenol-formaldehyde novolak resins, 2,2-bis(4-hydroxyphenyl)propane (otherwise know~l as bisphenol A), a~d 2,2-bis(3,5-dibromo-4-, hydroxyphe~yl)propane.
- There may further be employed poly(N-glycidyl) and poly(N-~-methylglycidyl compounds, for example, those obtai~ed by dehydro-chlori~ation of the reaction products of epichlorohydrin and amines containing at least two hydrogen atoms directly attached to nitrogeu, such as aniline, n-butylamine, bis(4-aminophe~yl)methane, - bis(4-aminopheuyl) sulphone, and bis(4-methylaminophenyl)methane.
Other poly(N-glycidyl) compounds that may be used include triglycidyl isocyanura~e, N,N'-diglycidyl deriva~ives of cyclic alkylene ureas such as ethyleneurea and 1,3-propyleneurea, and N,N'-diglycidyl derivatives of hydantoins such as 5,5-dimethylhydantoin.
Other polyepoxides which may be used include bis(2,3-epoxycyclo-pentyl) ether, 2,3-epoxycyclopentyl glycidyl ether, and 1,2-bis(2',3'-epoxycyclopentyloxy)ethane.
Especially suitable epoxide resins are polyglycidyl ethers o~

;341~9 2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane, or of a novolac from phenol (which may be substituted in the ring by chlorine or a hydrocarbon alkyl group of from 1 to 4 carbon atoms) and formaldehyde, having an epoxide content of at least 1.0 epoxide equivalent per kilogram.
Also suitable as component c) are sources of formaltehyde; by means of these, crosslinking i9 induced by the formation of methylene or methylene ether bridges, at vacant sites ortho or para to a phenolic hydroxyl group, in between the aromatic nuclei of the addition products formed from tbe unsaturated phenol a) and the polymercaptan b). Typical such sources of formaldehyde are hexa-methylenetetramine and paraform.
The compositions of this invention comprising components a), b), and c) mayjbP used as surface coatings. They ~ay be applied to a substrate such as steel, aluminium, copper, cadmium, zinc, tin, glass, ceramic, paper, or wood, prefarably as a liquid, and polymerised, and they are then heated to cure them. By polymerising through irradiation part of the coating, as thro~gh a mask, those sections which have not been exposed may be washsd with a solvent to remove the unpolymerised portions while leaving the photopolym~rised, insoluble sections n place. Thus the compositions of this invention may be used in the production of printing plates and printed circuits.
.~ethods of producing printing plates and printed circuits from photopolymerisable compositions are well known (see, e.g., our British Patent specification No. 1 495 746).

. .

., ~

~3~;34~

The photopoly~erised products obtai.ned from compositions containing components a), b), and c) are particularly useful in the production of multilayer printed circuits.
Conve~tionally, a multilayer printed circuit is prepared from a number of double-sided printed circuit boards of copper, stacked one on top o~ another and separated from each other by insulating sheets, usually of glass fibre impregnated with a phenol-formaldehyde resin or an epoxlde resin in the B-stage. The stack i9 heated and compressed to bond the layers together. Photopolymerisable materials commonly available hitherto, however, do not form strong bonds either with copper or with resin-impregnated glass fibre sheets. A
stack which is bonded with the photopolymer still covering the copper i3 there~ore inherently weak a~d in use can become delaminated. It is therefore normal practice to remove the residual ~- 15 photopolymer after the etching stage, either by mez~s of powerful solvents or by a mechanical method, e.g., by mea~s of brushes. Such a strippi~g process can damage the copper of the printed circuits or the surface of the laminate on which the circuit rests, and so there is a need for a method which would avoid the necessity of removing the photopolymerised material prior to bonding the boards together. The presence of phenolic hydroxyl groups in the polymerised com~ositions of this invention means that crosslin~ing can occur when the boards are bonded, resulting in good adhesion to the copper and to the resin-imæregnated glass fibre substate, so avoiding the necessity just referred to; also, products with a higher glass : - . - : : . ~ :

~- . , ~. .: :
:- , , ~ .

~L~3~3~3 transition temperature are obtained.
The compositions comprising conponents a), b), and c~ may also be used as adhesives. Employing irradiation to intuce polymerisation, a layer of the composition may be sandwiched between two ~urfaces of objects, at least one of which is transparent to the zctinic radiation, e.g., of glass, then the assembly is heated. Or a layer of the composition in liquid form may be irradiated until it solidifies, producing a film adhesive which is then placed between, and in contact with, the ~wo surfaces which are to be bonded, and is heated to complete crosslinking of the composition. The film may be provided with a strippable backing sheet, e.g., of a polyolefin or a polyester, or of cellulosic paper having a coating of a silicone release agent on one face. Mbnipulation of the assembly is often easier if the film has a tacky surface. This may be produced by coating the film with a substance which is tacky at room temperature but which is crosslinked to a hard, insoluble, infusible rPsin under the conditions of heat employed to effect crosslinking of the compositions by means of the phenolic hydroxyl groups. However, an adequate degree of tackiness ofte~ exists without additional treatment, especially if polymerisation of the composition has not proceeded too far. Suitable adherends include metals such as iron, zinc, copper, nickel, and aluminium, ceramics, glass, and rubbers. When free-radical catalysts are used to ini~iate polymerisation, a layer of the composition contai~ing such a catalyst may be placed between, and in contact with, two surfaces to be joined, and the assembly is , :

.~ .,. : ~ . :
: .. :
~, , .
~ ;.' : .
, : , . :~ ~.' '.:, ,': ' . :
. .

~3~3~

heated. Alterrlatively, a film adhesive may be made, but th2 amount of heat applied must, of course, be carefully controlled so that the ; film adhesive is still thermally curable when it is subsequently employed to bond surfaces together.
The compositions containing components a), b), and c) are alio useful in the production of fibre-reinforced composites, including sheet moulding compounds. They may be applied directly, in liquid form, to reinforcing fibres (including strands, filam~nts, and whiskers), which may be in the form of woven or nonwoven cloth, unidirectional lengths, or chopped strands, especially glass, boron, stainless steel, tu~gsten, alumina, silicon carbide, asbestos, potassium titanate whiskers, an aromatic polyamide such as poly(m-phenylene isophthalamide~ ~ poly(~phenylene terephthalamide) or poly(~-benzamide), polyethylene, or carbon.
It is not necessary to convert imnediately a polymerised composition, made from components a), b), and c), distributed o~
the fibres into the fully crosslinked, insoluble, and infusible C-stage; often it ca~ be changed into the still fusible B-stage, or remaiu in the A-stage, and, when desired, e.g., after stacking to form a multilayer laDinat~, and/or after the impregnated material ; has been fo D d into some desi~ed configuration, fully crosslinked by heating (or further heating). For example, if a hollow shaped article is required, i~ is convenient to impregnate a continuous tow of fibrous reinforcement and wind the tow around a former while9 at the same time, e.~osing the winding to actinic radiation. Such .. ..
.: -~ " ~ " ' .. , ' ~ ;

~.~3~3~(~

windings still have a certain degree of flexibility, permitting the former to be removed re easily than when a rigid winding i9 formed in one step. When required, the so--called filament windin~ i5 heated to crosslink the compositio~ a~d complete the cure.
Alteruatively, the composition comprising components a), b), and c) may be made into a fil~ adhesive as above, this ~ilm i9 applied to a layer of reinforcing fibres, and then the components of the film are caused to flow about the fibrous material by the application of heat and/or pressure.
This latter procedure is particularly convenient when unidirectional fibrous reinforcement is to be used, especially if the fibres are short and/or light, because there is less tendency for the fibres to become displaced a~d the reinforcing e~fect thereby become irregularly tistributed.
For applying heat and pressure, heated platens or pairs of rollers may be used for example, and in the latter case, when unidirectio~al fibres are used, a rolling pressure may be applied in the direction in which the fibres are aligned. In place of pairs or rollers, the assembly may be passed under tension around the periph~ry of a single roller.
; The fibre-reinforced composite may be made by a batch process, the fibrous reinforcing material being laid on the film of the polymerised composition, which is advantageously under slight tension, when a second such film way, if de~ired, be laid on top, ~nd then the assembly is pressed while being heated. It may also be made ~, , : ~. . - .

~L3634(;~

continuously, such as by contacting the fibrous reinforcing material with the film of the polymerised co~osition, then, if desired, placing a second such film on the reverse face of the fibrous reinforcing material and applying heat and pressure. More 5 conveniently, two such films, preferably supported on the reverse - side belts or strippable sheets, are applied simultaneou~ly to the fibrous reinforcing material so as to contact each exposed face.
When t~o such films are applied, they may be the same or different.
Multilayer composites may be made by heating under pressure interleaved films and layers of one or more fibrous reinorcing ~` materials. When unidirectional fibres are used as the reinforcement material, successive layers of them may be oriented to form cross-ply structures.
With the fibrous reinforcing material there may be used additional types of reinforcement such as a foil of a metal (e.g., aluminium, steel, or titanium) or a sheet of a plastics ma~erial (e.g., an aromatic or aliphatic polyamide, a polyimide, a poly-sulphone, or a polycarbonate) or of a rubber (e.g., a neoprene or acrylonitrile rubber).
In the production of sheet moulding conpounds, a com~osition of this inve~tion comprising components a)~ b), and c), and, if used, the photoiuitiator, together with the chopped strand reinforcing material and a~y other compo~ents, are e~posed to irradiation in layers through supporting sheets. Alter~atively, a free-radical catalyst may be employed, avoiding ~he use of a degree ~. , , : :

,, . , : . . .

~3~3~3 - 2~ -of heat that would cause thermal crosslinkin~ until required.
The polymerisable composition and, if uset, the photoinitiator or the free-radical catalyst, are preferably applied 90 that the composite contains a total of from 20 to 80~ by weight oP the ~aid components and, correspo~dingly, 80 to 20% by weight of the reinforcement. Mare preferably, a total of 30 to 50% by weight of these component~ and 70 to S0% by weight of the reinforcement are employed~
The compositions of this invention comprisin~ component a), b), and c) are also useful in the production of putties ant fillers, and as dip-coating compositions, an article to be coated being . dipped in a liquid composition of this invention a~Ld withdrawn, irradiated so that the adhering coating solidifies, and then is heated to complete the cure. Alternatively, the composition may be caused to solidify by activating a free-radical catalyst.
Compositions containing co~ponenes d) and e) are, as already irLdicated, useful for forming crosslinked coatings which usually hava e~cellerLt adhesion to polar substrcLtes such as metals, gla~s, and ceramics.
The three component compositions may be supplied as two packs, one containing the u~saturated phenol a) and the other the polymercap~a~ b), the crosslirLking agent c~ being contained i~
either or both packs. Of course, ~hey may also be in the form of three compo~e~t packs, ~Le containing the phPnol a), a second the polymercaptan b), and the third the crosslinking agent c). ~hen .

, , . ~ .. . , ,, . : ~ .

~' ; " .
: . : ..

11363~(J

the two component compositious, i.e., those containing an at least dihydric phenol d) and an at least trimercaptan e), are required, the~e may likewise be marketed in two component packs, one containing co~po~ent d) aud one containi~g co~ponent e).
Otherwise, the compositions may be stored as mixtures until required, pro~ected from actinic radiation and sources of ~ree radicals.
The followin~ Examples illustrate the inven~ion. Parts are ~y weight and temperatures are in degrees Celsius.
Flexural stre~gths are the mean of three results and were determined according to British Standard No. 2782, Method 304B.
Lap shear strengths are also the mean of three results~ and were detennined according to the British Ministry of Aviation, Aircraft Specification DTD 5577, of November 1965.
2,2-Bis(3-allyl-4-hydroxyphenyl)propane, used in the Examples, was prepared in the following manner.
2,2-Bis(4-hydrosyphe~yl)propa~e (22~ g), sodium hydroxide (82.5 g), and n propanol (1 litre) were heated under reflux, and when all was in solution, allyl chloride (200 ml) was added slowly~
After 3 hours the mixture was practically neutral. It was stirred unter reflux for a further 3 hours, the precipitated sodium chloride was filtered off~ a~d ~he n-propanol was removed by tistillation.
The crude 212-bis(4-allyloxyphenyl)propane was taken up in methylene chloride, washed with water and, after separation of the aqueous phase, the methylene chloride was distilled off and the pure diallyl ,, , " . ~ ............ ... .. . . .. .

' ~3L3~34~

~ 30 -ether remaining was dried over sodiu~ sulphate.
To convert the diallyl ether into the desired diallylbisphenol it was heated, as an approximately 50% solution in diethylene glycol monoethyl ether, at 200-205 . The product was purified by heating it in a rotary evaporator and then by vacuum distillation (b.p.
190/0.5 mm) ! Microanalysis, gas chromatography, gel permea~ion chromatography, and NMR and IR-spectroscopy were used to confirm the structure of the intermediary diallyl ether and the r~arranged product.
Bist3-allyl-4-hydroxyphenyl)methane and 3,3'-diallyl-4,4'-dihydroxydiphenyl can be prepared in the same way, from bis(4-hydroxyphenyl)methane and 4,4'-dihydroxydiphenyl, respectively.
2,2-Bis~3-(1-propenyl)-4-hydroxyphen~l)propane was prepared as ~ollows:
2,2-Bist3-allyl-4-hydroxyphenyl)propane (1 mole) was mixed with potassium hydroxide pellets (2.2 moles) and the mixture was stirred and heated at 110 for 30 minutes. The mixture was cooled9 neutralised with dilute hydrochloric acid, and the product was ~xtracted to give methylene chloride. The solution was dried and evaporated to give substantially pure 2,2-bis(3-(1-prope~yl)-4-hydroxyphenyl)propane.
Proton N~R and IR-spectroscopy were used to confirm the assigned structure. More detailed studies using 13C NMR, however, sho~ed the preseuce of minor amounts of isomeric material such as 2-(3-(l-isopropenyl)-4-hydroxyphenyl)-2-(3-(1-isopropenyl)-2-hydroxy-phenyl)propane, believed to be formed by thermal scission and ' ~ ' . . ' ' :

3L~;3634~

recombinatiou of the product.
2,2-Bis(3,5-diallyl-4-hydroxyphenyl)propane was prepared by conversio~ of 2,2-bis(3-allyl-4-hydroxyphenyl)propane iuto it~
diallyl ether and subjecting this to a Claisen rearrangeme~t as described above. Its allyl double bond conteut waq 10.3 equiv./kg.
Rearrangemeut of 1,3-diallyloxybenzene a~orded a mixture of the two isome~ic phenol~ 1,3-diallyl~2,4-dihydro~ybenzene and 1,5-diallyl-2,4-dihydroxybe~zene. The mixture had an allylic double bond content of 10.53 equiv~/kg.
Bis(3-allyl-4-hydroxyphenyl) sulphone wa~ prepared by rearrangement of bis(4-allyloxyphenyl) sulphone; its allylic double bond content wa3 6.71 equiv./kg.
The polymercaptans employed were comm2rcially-available materials, having the following thiol content3:

Pol~mercaptan Ethylene glycol dithioglycollate 9,05 Trimethylolpropane trithioglycollate 8.0 Pentaerythritol tetrathioglycollate 8.8 Tris(3-mercapto-2-hydroxypropyl ether) o~ 3.6 a poly(oxypropyIene)triol of average molecular weight 800 Dipentae~ythritol hexakis(3-~ercaptopropionate) 7.3 A polysulphide of fornula XXII, below 2.0 ~3~34~

_32_ Hexamine ( 5 parts) was d;ssolved in a mixture, warmed to 40, of ethylene glycol dithioglycollate ( 68 parts), 2,2-bis(3-allyl-4-hydroxyphenyl)propane ~ 100 parts~ i.e., 1 allyl group equivalent per mercaptan group), andbenzil dimethyl acetal ( 4 parts). Glasscloth (plain weave, weighing 200 g/m2, with an epoxysilane finish) was impregnated at room temperat~re with this composi~ion and then it was exposed on both sides for 1 minute, at a distance of 18 cm, to a 400 w high pressure metal halide-quartz arc lamp radiating predominantly in the 365 mm waveband. A tack-free prepreg was obtained.
Six 10-cm square pieces of the prepreg were stacked and heated at 180 for 1 hour under an applied pressure of 0.69 MN/m2, allowing a dwell time of 3 minutes before applying maximum pressure. The laminate was further heated at 180 for 1 hour without applied pressure~ It had a flexural strength of 265 M~/m2, and was composed of 57.2% of glass.

A liquid composition was prepared by stirring 2,2-bis(3-allyl-4-hydroxyphenyl)propane (100 parts)S trimethylolpropane trithioglycollate 20 (81 parts, i.e., 1 allyl group equivalent per mercaptan group), be~zil dimethyl acetal ( 4 parts), a polyglycidyl ether of a phanol formaldehyde novolac, having an epoxide content of 5.6 equiv./kg, the molar ratio of phenol to formaldehyde in the novolac being 1:0.72 (115 parts), and 2-phenylimida7O1e (2 parts). This composition ~as 25 coated onto a polyamide carrier film at room temperature and converted into a tack-frele film by irradiation on both sides for 30 seconds with a 400 w high pressure metal halide-quartz lamp at a distance of 18 cm.

, . . ..... .. . .. ., , .. . ._ .. _ . . ......... .. .

,: , : .. .. . .

, :.:-"............ ,, - ' ~3~i3~0

-3~

The film adhesive so obtained was cut to size and sandwiched between two sheets of "Alclad 3L 73" aluminium alloy that had been degreased in trichloroethylene and pickled in chromic acld solution ("Alclad" is a registered Trade Mark). Gverlap joints of 1.27 cm were S prepared by pressing the assembly under a pressure of 0.34 MW/m2 for 1 hour at 180. The lap shear strength of the joints was 6.4 MN/m2.
E~AMPLE 3 The procedure of Example 2 was repeated except that there was used 115 parts of trimethylolpropane trithioglycollate, i.e., 0.7 allyl group equivalent per mercaptan group. The lap shear strength of the joints was 5 M~tm2.
E2~MPLE 4 A surface coating was prepared by applying a mixture comprising 100 parts of 2,2-bis(3-allyl-4-hydroxyphenyl~propane, 74 parts of pentaerythritol tetrathioglycollate, i.e., l allyl group equivalent per mercaptan group, 5 parts of bexamethylenetetramine, and 4 parts of 232'-azobis(2-methylpropionitrile2 as a layer 4 ~m thick on degreased and pickled aluminium sheets and heatiig for 1 hour at 80 and then for one hour at 180. The coating was non-tacky, and was not affectet by 20 rubs with an acetone-soaked cotton wool swab.

A mixture was prepared as in Example 4 but containing 140 parts of pentaerythritol tetrathioglycollate, i.e., 0.5 allyl group equivalent per mercaptan group, and 0.25 par~ of hexamethylenetetramin~; it was applied sil~ilarly, and then cured by heating for 1 hour at 80 and then 1 hour at 180. The coating, which was not tac~y, was unaffected by 20 rubs with an acetone-soaked swab.

~ ~ ... , "

~3~i3~L~

~ 34-A liquid composition wa~ prepared by stirring 2,2-bis(3-(1-propenyl)-4-hydro3yphenyl)propane (100 parts), trimethylolpropane trithioglycollate (115 parts, i.e., 0.7 propenyl group equivale~t per mercaptan group), benzophenone (4 parts), a polyglycidyl ether of a phenol-formaldehyde novolac as described in Example 2 (115 parts), and 2-phenylimidazole (2 parts).
Glasscloth (plain weave, weighing 200 g/m2, with an epoxysilane finish) was impregnated at 40 with this composition ant then it was exposed on both sides for 30 seconds, at a distance of 15 cm, to a 400w high pr2ssure metal halide arc lamp radiating predominantly in the 365 nm waveband. A tack-free prepreg was obtained.
Four 10-cm square pieces of the prepreg were stacked and . 15 heated at 170 for 1 hour under an applied pressure of 0.69 ~N/~2, allowing a dwell time of 3 minutes before applyi~g maximum pressure. The laminate produced had a flexural s~rength of 226 MN/m2 a~d contained 31.3% of glass.
~7~U~nL~ 7 A liquid composition was prepared by stirring 2,2-bis(3~
prope~yl-4-hydroxyphenyl)propane (100 parts)g trimethylolpropane trithioglycolla~e ~81 par~sJ i.e., 1 propenyl group equivalent per mercaptan group), benzil dimethyl ace~al (4 parts), a polyglycidyl ethler of a phenol- ormaldehyde novolac as described in Example 2 (115 parts), a~d 2-phenylimidazole (2 parts). This - :: : . . . . .. . ..

~3~;~4~

composition was coated at room temperature onto a polyamide carrier film, supported on siliconised paper, and converted into a tack-free film by irradiation under a 400 w metal halide quartz arc lamp at a distance of 15 cm ~or 30 seconds.
Overlap joints were made from the film adhesive 50 obtained as described in Example 2: their lap shear stren8th was 5.3 ~N/m .

A surface coating was prepared by applying a mixture comprising 100 parts of 2,2-bis(3-(1-prope~yl)-4-hydroxyphenyl)-propane/ 74 parts of pentaerythritol tetrathioglycollate, i.e., 1 propenyl group equivalent per mercaptan group, 5 parts of hexamethylena~etramine, and 4 parts of 2,2'-azobis(2-methyl-propionitrile) as a layer 6 ~m thick on degreased and pickled aluminium sheets a~d heating for 1 hour at 80 followet by 1 hour at 180 . The coating was tack-free and resisted re than 20 rubs with an acetone-soaked swab.
E~AMPLE 9 A mixture of 10 parts of 2,2-bis(3,5-diallyl-4-hydroxyphenyl)-propane, 28.7 parts of a tris(3-mercapto-2-hydroxypropyl) ether of a poly(oxypropylene) triol of average molecular weight 800 (i.e., 1 allyl group equivalent per mercaptan group), benzil di~ethyl acetal (1 part), ant hexam1ne ~0.5 part) was applied as`a coating 6 ~m thîck o~to ti~plateO The coating was irradiated with 500 watt medium pressure mercury la~p at a tistance of 20 cm, and it was tack-free on 45 seconds' exposure. The coating was resistant ... . . , .. .. , ,, . . .. , .. _: _ .. . ...... .

.

~gL3f~3~(~

to 11 rubs with an acetone-soaked cotton wool swab; on being heated for 1 hour at 180 it was resistant to more than 20 ~uch rubs.
EXAMoeLE 10 A coating 6 ~m thick was applied to tinplate, co~sisting of a mi~ture of 1,3- and 1,5-diallyl-2,4-dihydroxybenzene (10 parts~, 52.6 parts of a mercaptan polysulphide of average ~ormula Hs-~c2~4-o-c~2-o-c2H4-s-s~6c2H~-o-cH2-o-c2H4-sH XXII

i.e., 1 allyl ~roup equivalent per mercaptan group equivalent, 1 part of benzil dimethyl acetal, and 0.5 part of hexa~ne. The coating was irradiated with a 1200 w medium pressure mercury lamp at a dist~nce of 22 cm; it became tack-free in 25 seconds, and resistant to 8 rubs with an aceto~e-soaked cotton wool swab.
After being heated for 1 hour at 180 the coating withstoot more than 20 such rubs.

_ ..
The procedure of Example 10 was repeated, using 10 parts of bis(3-allyl-4-hydroxyphenyl) sulphide in place of the mixed diallylphenols and 33-5 parts of the poly5ulphide of formula XXII, i.e., 1 allyl group equivale~t per mercaptan gro~p. Similar results were achieved, irradiation for 35 seconds, however, being required before the coating was tack-free; it was resistant to 8 rubs with an acetone-soaked co-to~ wool swab. After being heated at 180 for 1 hour the coating withs~ood more than 20 such rubs.

.. .... . ... .. .. .... .. . . .... ... . .. . . . . . . . ..

: - ~ . : ,:

, .. ;:

:~ : . ~. .

~13~3~

._ ~
Benæophenone (10 parts) was dissolved in a mixture of 2,2-bis(3-allyl-4-hydro~yphenyl)propane (100 parts) and pentaerythritol tetrathioglycollate (74 parts, i.e., 1 allyl group S equivalent per mercaptan group). Tha liquid composition was applied as a coating 4 ~m thick onto tinplate at room temperature and irradiated under a 500 w medium pressure mercury lamp at a distance of 20 cm. After 75 seconds the coating had become tack-free, and after 3~ minutes' irradiation it had become alst completely cured, being resistant to 12 rubs with a cotton wool swab soaked in acetone.
EX~MPLE 13 Benzil dim~thyl acetal (10 parts) was dissolved in a mixture of 2,2-bis(3-allyl-4-hydroxgphenyl)propa~e (100 parts) and 179 part9 of the tris(3-mercapto-2-hydroxypropyl) e~her used in Example 9, i.e.~ 1 allyl group equivalent per me~captan group. A
coating was prepared as in E~ample 12 and irradiated with a 1200 w medium pressure mercury lamp at a distance of 22 cm. ~fter 10 seconds' irradiatio~ the coating was tack-free, and after 25 seconds' ir~adiation it was resista~t to 20 rubs with a cotton wool swab soaked in acetone.
E~ PLE 14 A surface coating was prepared by applying a m'xture comprising 100 parts of 2,2-bis(3-allyl-4-hydroæyphenyl)propane, 74 parts of pentaerythritol tetrathioglycollate, i.e., 1 allyl group equivalent per mercaptan group, and 4 parts of 2,2'-- : , . . ,,. ,. - :,:: -: ~. :

~13~34(:~

azobis(2-methylpropionitrile) as a layer 4 um thick on degreased and pickled aluminium sheets and heating for 1 hour at 80. The coating was non-tacky, and withstood 4 rubs with an acetone-soaked swab.

Benzophenone (10 parts) was dissolved in a mixture of 2,2-bis(3-allyl-4-hydroxyphenyl)propa~e ~100 parts) and dipentaerythritol hexakis(3-mercaptopropionate) ~8.5 parts, i.e., 1 alIyl group equivalent per mercaptan ~roup). The liquid composition was applied as a coating 4 ~m thick onto tinplate and irradiated under a 1200 w medium pressure mercury lamp at a distance of 22 cm.
After lO seconds the coating was tack-free and after 35 seconds it was resistant to 20 rubs with an acetone-soaked swab.

. _ _ Benzophenone (10 parts) was dissolved in a mixture of 2,2-bis(3-(1-propenyl)-4-hydroxyphenyl)propane (100 parts) and pentaerythritol tetrathioglycollate (74 parts, i.e., l propenyl group equivalent per mercaptan group?. The liquid compo~ition was applied as a coating and irradiated a in Example 15. After 5 seconds the coating had become tack-free, and a~er 25 seconds' irradiation it was resistant to 16 rubs with a cotton wool swab soaked in acetone.
E~AMPLE 17 A mixture was prepared as in Example 13, using, however lO0 parts of 2,2-bis(3-(1-propenyl)-4-hydroxyphenyl)propane, i.e , 1 propenyl group equivalent per mercaptan group. A coating was : :
:: , J : ': :, . ' '' ' ' '' , , ,:
~. ' -: " '`'' ' ' ' : ' ~L3~3~0 prepared as i~ Exam~le 12, applied at 40, and irradiated as in Example 12. After 1 ~inute's irratlation, a flexible, tack-~ree coating was obtained. ~fter 3~ minutes' irradiation the coating was resistant to 20 rubs with an acetone-soaked swab.
E~AXPLE 18 A surface coating was prepared by applying a mixture comprising 100 parts of 2,2-bis(3-(1-propenyl)-4-hydroxyphenyl)propan~, 74 parts of pen~aerythritol tetrathioglycollate, i.e., 1 propenyl group equivalent per mercaptan group, and 4 parts of 2,2'-azobis~2-methylpropionitrile) as a layer 6 ~m thick on degreased ant pickled aluminium sheets and heating for 1 hour at 80. The coating was tack-free and resisted 10 rubs wi~h an acetone-soaked swab.

Benzophenone (10 parts) was dissolved in a mixture of 2,2-bis(3-allyl-4-hydroxyphe~yl)propane (100 parts) and pentaerythritol tetrathioglycollate (140 parts, i.e., 0.5 allyl group equivale~t per mercaptan group). The liquid composition was applied as a coating 6 ~m thick onto tin foil at room tem~srature and irradiated as in Example 12~ After 90 seconds the coating had become tack-free a~d after 5 mi~utes' irradiation it had become almost co~pletely cured, being resistan~ to 18 rubs with a cotton wool swab soaked in acetone.

A composition was made as in Example 13 except tha~ 107 parts of the mercapt~n was used, i.e., 1.7 allyl group equivalents per ~3~3~C~

~ 40 -mercaptan group. A coating was prepared as in Example 14, and after 3~ minutes' irradiation a flex:ible, tack-free coating had been obtained.

____ The procedure of E~ample 14 was repeated, uging, however, 140 parts of pentaerythritol tetrathioglycollate, i.e., 0.4 allyl ~roup equivalent per mercaptan group. The coating was tacky, but withstood more than 20 rubs with an acetone-soaked swab.

A mixture of 2,2-bis(3,5 diallyl-4-hydroxyphe~yl)propane (10 parts), trimethylolpropane trithioglycollate (12.9 parts, i.e., 1.0 allyl grcup equivalent per mercaptan group), and benzil dimethyl acetal (0.1 part) was applied as a layer 6~m thick onto tin foil a~d irradiated under a 500 w medium pressure 15 mercury lamp at a distance of 20 cm for 40 seconds, to give a tack-free coating.

: :. , . . . :
- , . - ;-:

: , , ~. .: .
: . . . . .. .

':~ ' ' " , ~
, ::: ,: . :

Claims (10)

WHAT IS CLAIMED IS:

1. Polymerisable compositions comprising a) a compound containing in the same molecule both at least one phenolic hydroxyl group and at least two groups chosen from allyl, methallyl, and 1-propenyl groups, b) a compound containing at least two mercaptan groups per molecule, such that a) provides a total of from 0.4 to 2.4 equivalents selected from allyl, methallyl, and 1-propenyl group equivalents per mercaptan group equivalent in b), and c) a heat-activated crosslinking agent for phenol-aldehyde novolac resins.

2. The compositions of claim 1, in which each group chosen from allyl, methallyl, and 1-propenyl groups in the compound a) is attached either to a carbon atom which forms part of an aromatic nucleus or to an oxygen atom which in turn is directly attached to a carbon atom which forms part of an aromatic nucleus.

3. The compositions of claim 2, in which the compound a) is a polyhydric phenol, partially etherified with at least two groups chosen from allyl, methallyl, and 1-propenyl groups, or is a phenol substituted in the aromatic nucleus or nuclei by at least two groups chosen from allyl, methallyl, and 1-propenyl groups.

4. The compositions of claims 1,2 or 3,wherein the compound b) is an ester of a monomercaptancarboxylic acid with a polyhydric alcohol or of a monomercaptanmonohydric alcohol with a polycarboxylic acid, especially a poly(thioglycollate) or a poly(2- or 3-mercaptopropionate) of an aliphatic polyhydric alcohol of 2 to 6 carbon atoms.

5. The compositions of any of claims 1 to 3, wherein the compound b) is of one of the formulae XIII, XIV, XVII, XVIII, XX, and XXI

XIII

where d and e each represent zero or 1 but are not the same, f is an integer of from 1 to 6, R9 represents a divalent radical, linked through a carbon atom or carbon atoms thereof to the indicated -O- or -CO- units, R10 represents a divalent organic radical, linked through a carbon atom or carbon atoms thereof to the indicated -SH group and -O- or -CO- unit, and R11 represents an organic radical, which must contain at least one -SH group when f is 1, linked through a carbon atom or carbon atoms thereof to the indicated -O- or -CO- unit;
XIV

where R12 represents the radical of a polyhydric alcohol after removal of (j + k) alcoholic hydroxyl groups, each R13 denotes an alkylene group containing a chain of at least 2 and at most 6 carbon atoms between consecutive oxygen atoms, R14 represents an aliphatic radical of 1 to 6 carbon atoms, containing at least one mercaptan group, g is a positive integer, h is zero or 1, j is zero or a positive integer such that (j + k) is at most 6, and k is an integer of from 2 to 6;

XVII

where each R15 denotes an alkylene hydrocarbon group containing from 2 to 4 carbon atoms, R16 denotes -H, -CH3, or -C2H5, n is an integer which has an average value of at least 1, and either p is zero, in which case q and r are each also zero, or p is 1, in which case q is zero or 1 and r is 1;

XVIII

where each R17 represents -H or -CH3, R18 represents -CN, -COOH, -CONH2, -COOR19, -C6H5, or -OCOR19, where R19 is an alkyl group of one to eight carbon atoms, t is an integer of at least one, u is zero or a positive integer, and s is an integer of more than one;

XX

where each R17 represents -H or -CH3 and x is an integer of from 1 to 4;
or XXI
where each R8 denotes -CH2-, -(CH2)2-, or -CH(CH3)-, each R17 denotes -H or -CH3, and R20 denotes -H or a group -COR8SH.

6. Compositions according to claims 1,2 or 3, which also contain a photoinitiator.

7. Compositions according to any of claims 1 to 3, which also contain a free-radical catalyst.

8. Polymerisable compositions comprising d) a compound having in the same molecule both at least two phenolic hydroxyl groups and at least two groups chosen from allyl, methallyl, and 1-propenyl groups, and e) a compound containing more than two mercaptan groups per molecule, such that d) provides a total of from 0.4 to 2.4 equivalents selected from allyl, methallyl, and 1-propenyl group equivalents per mercaptan group equivalent in e).

9. Compositions according to claim 8, which also contain a photoinitiator.

10. Compositions according to claim 8, which also contain a free-radical catalyst.