Hydroxyl-containing compositions and their polymerization

Polymerizable compositions comprise PA1 (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-hydroxyphenyl)propane or bis(3-(1-propenyl)-4-hydroxyphenyl)methane, PA1 (b) a compound containing at least two mercaptan groups per molecule, e.g., pentaerythritol tetrathioglycollate, and PA1 (c) a heat-activated crosslinking agent for phenol-aldehyde novolac resins. The compositions are caused to polymerize by the action of irradiation of 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. Polymerizable compositions may also comprise PA1 (d) a compound as (a) but containing at least two phenolic hydroxyl groups, PA1 (e) a compound containing more than two mercaptan groups per molecule. On irradiation or on heating in the presence of a catalyst, preferably a free-radical catalyst, these compositions crosslink, they are useful as adhesives in forming coatings on polar substrates.

BACKGROUND OF THE INVENTION 
This invention relates to compositions containing a polymercaptan and a 
compound which has both at least two allyl, methallyl, or 1-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 composites, and as adhesives. 
For a number of reasons it has become desirable to induce polymerisation of 
synthetic resin compositions by means of actinic radiation. Employing 
photopolymerisation procedures may, for example, avoid the use of organic 
solvents with their attendant risks of toxicity, flammability, and 
pollution, and the cost of recovering the solvent. Photopolymerisation 
enables insolubilisation of the resin composition to be restricted to 
define areas, i.e., those which have been irradiated, and so permits the 
production of printed circuits and printing plates or allows the bonding 
of substrates to be confined to requires zones. Further, in production 
processes, irradiation procedures are often more rapid than those 
involving heating and a consequential cooling process. 
We have now found that valuable products can be made by photopolymerisation 
of compositions containing a polymercaptan and a compound which contains 
both at least one phenolic hydroxy group and at least two allyl, and/or 
methallyl, and/or 1-propenyl groups. We have found, too, that such 
compositions may also be polymerised by means of free-radical catalysts. 
The composition, comprising polymerised material containing residual 
phenolic hydroxyl groups, may be further crosslinked, i.e., converted into 
the insoluble, infusible, C-stage on heating by means of a heat-activated 
crosslinking agent for phenolaldehyde novolac resins contained therein. 
Hence, a stepwise cure is possible. 
DETAILED DISCLOSURE 
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 
1-propenyl groups. 
(b) a compound containing at least two mercaptan groups per molecule, 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 1-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 crosslinking polymeric coatings having 
excellent adhesion to polar substrates such as metal 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 
1-propenyl groups, and 
(e) a compound having at least three mercaptan groups per molecule, and a 
process for the polymerization 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 catalyst (see, e.g., British Pat. Nos. 
1,215,591, 1,251,232, 1,292,722, 1,445,814, and U.S. Pat. Nos. 3,787,303, 
3,877,971, 3,900,954, and 3,908,039). There has been described, for 
example, such a reaction between compounds containing two, three, or more 
mercaptan groups and diallyl adipate 2,2-bis(4-allyloxyhenyl)-propane, 
2,4,6-tris(allyloxy)-s-triazine, 
2,2-bis(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-isocyanate, 
3,3'-dimethyl-4,4'-di-isocyanatodiphenol, 
3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, or 
4,4'-methylenebis(cyclohexyl isocyanate). When the sum of the number of 
allyl groups per average molecular of the allyl component and of the 
number of mercaptan groups per average molecule of the polymercaptan is 
more than 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 free radical catalyst. The 
resultant polymer, of low intrinsic viscosity, was converted into a 
crosslinked rubber by mixing it with hexamethylenetetramine and then 
heating. However, the addition of polymercaptans across the double bonds 
of allyl, methallyl, or 1-propenyl groups in compounds containing at least 
one phenolic hydroxyl groups in the presence of a heat-activated 
crosslinking agent for phenol-aldehyde novolac resins to form products 
which can be subsequently crosslinked in situ by heating, has not, it is 
believed, hitherto been described. Neither, it is believed, has the 
crosslinking of at least dihydric phenols containing two or more allyl, 
methallyl, or 1-propenyl groups by means of tri- and higher mercaptans 
been described. 
Preferably the component (a) or (d) contains 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 1-propenyl group is directly attached to an oxygen, 
nitrogen, or carbon atom, particularly 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. 
Especially preferred as components (a) or (d) are polyhydric phenols, the 
phenolic hydroxyl groups of which are partially etherified with allyl, 
methallyl, or 1-propenyl groups, or phenols substituted in the aromatic 
nucleus or nuclei by allyl, methallyl, or 1-propenyl groups, especially by 
an allyl, methallyl, or 1-propenyl group ortho to each phenolic hydroxyl 
group. 
The following formulae are those of examples of preferred compounds: 
##STR1## 
where 
R denotes a carbon-carbon bond, an alkylene group of 1 to 5 carbon atoms, 
an ether oxygen atom, a sulphur atom, or a group of formula --CO--, 
--SS--, --SO--, or --SO.sub.2 --, 
R.sup.1 denotes an allyl, methallyl, or 1-propenyl group, 
a is an integer of at least 1 in the case of component (a) and at least 2 
in the case of a component (d), 
each R.sup.2 denotes an allyl or methallyl group, 
each R.sup.3 denotes a hydrogen, chlorine, or bromine atom, or an alkyl 
group of 1 to 4 carbon atoms, and 
each R.sup.4 denotes an allyl or methallyl group or a hydrogen atom, such 
that at least two R.sup.4 each denote an allyl or methallyl group and in 
the case of a component (a) at least one R.sup.4 denotes a hydrogen atom 
and in the case of a component (d), at least two R.sup.4 each denote a 
hydrogen atom, 
with the proviso that, in formulae V and VI, the --CH.sub.2 -- groups shown 
are ortho- or para- to the indicated groups --OH, --OR.sup.2, and 
--OR.sup.4. 
Particularly preferred are 2,2-bis(3-allyl-4-hydroxyphenyl)propane, 
bis(3-allyl-4-hydroxyphenyl)methane, and their 3-(1-propenyl) analogues. 
Compounds of formulae I to V are obtainable by conversion of the 
corresponding unsubstituted phenols, i.e., those of formula IX 
##STR2## 
hydroquinone, 1,5- or 1,8-dihydroxynaphthalene, and a novolac of formula X 
##STR3## 
where R, R.sup.3, and a have the meanings previously assigned, and the 
--CH.sub.2 -- 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 orthoallylphenol into the ortho-1-propenylphenol by heating in the 
presence of a strong alkali. 
Compounds of formula VI are obtainable by partial 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 1-propenyl groups in the same phenolic nucleus, such as 
those of formula VII and VIII, are obtainable by etherification with, 
e.g., allyl chloride or methallyl chloride, of the ortho-allyl or 
ortho-methallyl phenol, followed by a second Claisen rearrangement and, 
optionally, isomerisation of allyl groups to 1-propenyl groups through the 
action of alkali. 
There may also be used as component (a) or (d) a product obtained 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 1-propenyl group, e.g., a phenol of formula I or II. 
Suitable diepoxides include diglycidyl ethers of dihydric alcohols, 
diglycidyl esters of dicarboxylic acids, di(N-glycidyl)hydantoins, such as 
1,3-diglycidylhydantoin and 3,3'-diglycidyl-1,1'-methylenebis(hydantoin), 
and diglycidyl ethers of dihydric phenols, e.g., of a dihydric phenol of 
formula IX. Alternatively, there may be used as component (a) or (d) a 
product obtained by advancement with a dihydric phenol, a dihydric 
alcohol, a dicarboxylic acid, or a hydantoin containing two NH groups, of 
a diepoxide containing at least one allyl, methallyl, or 1-propenyl group, 
such as the diglycidyl ether of a phenol of formula I. 
The advancement of diepoxides is a generally known reaction (see, e.g., H. 
Batzer and S. A. Zahir, J. Appl. Polymer Sci., 1975, 19, 585-600 and H. 
Lidarik, Kunststoff Rundschau, 1959, 4, 6-10) and can be used to prepare 
allyl- methallyl-, and 1-propenyl-containing phenols of the type used in 
this invention. 
A wide range of polymercaptans is suitable for use as component (b) or (e) 
in the compositions of this invention. Preferably the mercaptans are free 
from any allyl, methallyl, 1-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. 
Further preferred such esters are of the formula 
##STR4## 
where 
R.sup.5 represents an aliphatic or araliphatic hydrocarbon radical of from 
2 to 60 carbon atoms, which may contain not more than one ether oxygen 
atom, 
R.sup.6 represents a hydrocarbon radical, which may contain not more than 
one carbonyloxy group, and is preferably of from 1 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 component (e), 
c is zero or a positive integer 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 1, but are not the same. 
Yet further preferred esters are polymercaptans of formula XI which are 
also of the formula 
EQU R.sup.7 (OCOR.sup.8 SH).sub.b XII 
where 
b has the meaning previously assigned, 
R.sup.7 is an aliphatic hydrocarbon radical of from 2 to 10 carbon atoms, 
and 
R.sup.8 denotes --CH.sub.2).sub.2 --, --(CH.sub.2).sub.2, or 
--CH(CH.sub.3)--. 
Also preferred are mercaptan-containing esters, including esters of 
monomercaptandicarboxylic acids, of formula 
##STR5## 
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), 
R.sup.9 represents a divalent organic radical, linked through a carbon atom 
or carbon atoms thereof to the indicated --O-- or --CO-- units, 
R.sup.10 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 
R.sup.11 represents an organic radical, which must contain at least one 
--SH group either in the 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 --O-- or --CO-- unit or 
units. 
Preferably, R.sup.9 denotes, when d is zero, a saturated aliphatic 
unbranched hydrocarbon chain of 2 to 20 carbon atoms, which may be 
substituted by one or more methyl group 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, R.sup.9 preferably denotes 
(i) a saturated aliphatic hydrocarbon group of 2 to 10 carbon atoms, which 
may bear a mercaptan group, 
(ii) a cycloaliphatic-aliphatic hydrocarbon group of 5 to 34 carbon atoms, 
which may contain one or more ethylenically-unsaturated double bonds, or 
(iii) a mononuclear arylene hydrocarbon group of 6 to 12 carbon atoms. 
R.sup.10 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. 
R.sup.11 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 of 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 which are of the general formula 
##STR6## 
where 
R.sup.12 represents a radical of a polyhydric alcohol after removal of 
(j+k) alcoholic hydroxyl groups, especially an aliphatic hydrocarbon 
radical of from 2 to 10 carbon atoms, 
each R.sup.13 denotes an alkylene group containing a chain of at least 2 
and at most 6 carbon atoms between consecutive oxygen atoms, 
g is a positive integer, preferably such that the average molecular weight 
of the polymercaptan is not more than 2,000, 
h is zero or 1, 
j is zero or a positive integer such that (j+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 
R.sup.14 represents an aliphatic radical of 1 to 6 carbon atoms containing 
at least one mercaptan group. 
The groups R.sup.13 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 --C.sub.2 H.sub.4 -- or --C.sub.3 H.sub.6 -- 
groups. 
Preferred amongst the compounds of formula XIV are the esters of formula 
##STR7## 
and ethers of formula 
##STR8## 
where 
R.sup.7, R.sup.13, g, j, 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 
##STR9## 
where 
each R.sup.15 denotes an alkylene hydrocarbon group containing from 2 to 4 
carbon atoms, 
R.sup.16 denotes --H, --CH.sub.3, or --C.sub.2 H.sub.5, 
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 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. 
The preferred sulphides of formula XVII are those where R.sup.16 denotes 
hydrogen and p 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 component (b) comprises 
mercaptan-terminated poly(butadienes) of the formula 
##STR10## 
where 
each R.sup.17 represents --H or --CH.sub.3, 
R.sup.18 represents --CN, --COOH, --CONH.sub.2, --COOR.sup.19, --C.sub.6 
H.sub.5, or --OCOR.sup.19, where R.sup.19 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 XVIII are also of the formula 
##STR11## 
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) 
comprises the mercaptan-terminated oxyalkylene compounds of the general 
formula 
##STR12## 
where 
each R.sup.17 has the meaning previously assigned and 
x is an integer of from 1 to 4. 
A still further class comprises poly(thioglycollates) and 
poly(mercaptopropionates) of tris(2-hydroxyethyl) isocyanurate and 
tris(2-hydroxypropyl) isocyanurate, i.e., the compounds of formula 
##STR13## 
where 
each R.sup.8 and R.sup.17 have the meanings previously assigned and 
R.sup.20 denotes a group --COR.sup.8 SH 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 atoms. 
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, methallyl, and 1-propenyl groups 
equivalents per mercaptan 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 total of from 0.4 to 2.4, especially 
0.8 to 1.2, allyl and/or methallyl and/or 1-propenyl group equivalents per 
mercaptan group equivalent in component (e). 
In photopolymerising the compositions of this invention, actinic radiation 
of wavelength 200-600 nm is preferably used. Suitable sources of actinic 
radiation include carbon arcs, mercury vapour arcs, fluorescent lamps with 
phosphors emitting ultraviolet light, argon and xenon glow lamps, tungsten 
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 determined by those familiar with photopolymerisation 
techniques, but when it is required that the products after 
photopolymerisation remain further crosslinkable by heating, 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 photoinitiators 
are organic peroxides and hydroperoxides, .alpha.-halogen substituted 
acetophenones such as trichloromethyl 4'-tert.butylphenyl ketone, benzoin 
and its alkyl ethers (e.g., the n-butyl ether), .alpha.-methylbenzoin, 
benzophenones such as benzophenone itself and 
4,4'-bis(dimethylamino)benzophenone, O-alkoxycarbonyl derivatives of an 
oxime of benzil or of 1-phenylpropane-1,2-dione, such as benzil 
(O-ethoxycarbonyl)-.alpha.-monoxime and 
1-phenylpropane-1,2-dione-2-(O-ethoxycarbonyl)oxime, benzil acetals, e.g., 
its dimethyl acetal, 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 experimentation. It 
is preferred that they do not give rise to a substantial degree of 
photoinducted 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 of the photopolymerisable 
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-isopropyl peroxydicarbonate, 
ammonium or an alkali metal perborate, ammonium or an alkali metal 
persulphate, acyl peroxides such as benzoyl peroxide, and also, e.g., 
cumyl peroxide, 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 already indicated, after the composition comprising components (a), (b), 
and (c) has been polymerised, it may be further crosslinked by virtue of 
the phenolic hydroxyl groups present. 
Another aspect of this invention therefore comprises a process for curing a 
polymerised composition comprising components (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, mixtures of compounds 
of differing molecular weight are obtained, these mixtures ordinarily 
containing a proportion of compounds whose epoxide groups have undergone 
partial hydrolysis. The average number of 1,2-epoxide groups per molecule 
of the resin need not be an integer of at least 2; it is generally a 
fractional number but must in any case be greater than 1.0. 
Examples of resins which may be used are polyglycidyl and 
poly(.beta.-methyglycidyl) esters obtainable by reaction of a substance 
containing two or more carboxylic acid groups with epichlorohydrin, 
glycerol dichlorohydrin, or .beta.-methylepichlorohydrin in the presence 
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 such as 
hexahydrophthalic acid, 4-methylhexahydrophthalic acid, tetrahydrophthalic 
acid, and 4-methyltetrahydrophthalic acid, and from aromatic carboxylic 
acids such as phthalic acid, isophthalic acid, and terephthalic acid. 
Other epoxide resins which may be used include polyglycidyl and 
poly(.beta.-methylglycidyl) ethers, such as those obtainable by reaction 
of a substance containing at least two alcoholic hydroxyl groups or at 
least two phenolic hydroxyl groups with the appropriate epichlorohydrin or 
glycerol dichlorohydrin under alkaline conditions or, alternatively, in 
the presence of an acidic catalyst with subsequent treatment with alkali. 
Such ethers may be derived from aliphatic alcohols, for example, ethylene 
glycol, diethylene glycol, triethylene glycol, and higher 
poly(oxyethylene) glycols, propylene glycol and poly(oxypropylene) 
glycols, propane-1,3-diol, butane-1,4-diol, pentane-1,5-diol, 
hexane-1,6-diol, hexane-1,2,6-triol, glycerol, 1,1,1-trimethylolpropane, 
and pentaerythritol; from cycloaliphatic alcohols such as quinitol, 
1,1-bis(hydroxymethyl)cyclohex-3-ene, bis(4-hydroxycyclohexyl)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-hydroxyethylamino)diphenylmethane. Preferably the ethers are 
polyglycidyl ethers of an at least dihydric phenol, for example, 
resorcinol, catechol, hydroquinone, bis(4-hydroxyphenyl)methane, 
1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, 4,4'-dihydroxydiphenyl, 
bis(4-hydroxyphenyl) sulphone, and phenol-formaldehyde, 
alkylphenol-formaldehyde, and chlorophenolformaldehyde novolak resins, 
2,2-bis(4-hydroxyphenyl)propane (otherwise known as bisphenol A), and 
2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane. 
There may further be employed poly(N-glycidyl) and 
poly(N-.beta.-methylglycidyl compounds, for example, those obtained by 
dehydrochlorination of the reaction products of epichlorohydrin and amines 
containing at least two hydrogen atoms directly attached to nitrogen, such 
as aniline, n-butylamine, bis(4-aminophenyl)methane, bis(4-aminophenyl) 
sulphone, and bis(4-methylaminophenyl)methane. Other poly(N-glycidyl) 
compounds that may be used include triglycidyl isocyanurate, 
N,N'-diglycidyl derivatives 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-epoxycyclopentyl) 
ether, 2,3-epoxycyclopentyl glycidyl ether, and 
1,2-bis(2',3'-epoxycyclopentyloxy)ethane. 
Especially suitable epoxide resins are polyglycidyl ethers of 
2,2-bis(4-hydroxyphenyl)propane, bis(4-hydroxyphenyl)methane, or of a 
novolac from phenol (which maybe 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 formaldehyde; by means of 
these, crosslinking is 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 the 
unsaturated phenol (a) and the polymercaptan (b). Typical such sources of 
formaldehyde are hexamethylenetetramine and paraform. 
The compositions of this invention comprising components (a), (b), and (c) 
may be used as surface coatings. They may be applied to a substrate such 
as steel, aluminium, copper, cadmium, zinc, tin, glass, ceramic, paper, or 
wood, preferably as a liquid, and polymerised, and they are then heated to 
cure them. By polymerising through irradiation part of the coating, as 
through a mask, those sections which have not been exposed may be washed 
with a solvent to remove the unpolymerised portions while leaving the 
photopolymerised, insoluble sections in place. Thus the compositions of 
this invention may be used in the production of printing plates and 
printed circuits. Methods of producing printing plates and printed 
circuits from photopolymerisable compositions are well known (see, e.g., 
our British patent Specification No. 1 495 746). 
The photopolymerised products obtained from compositions containing 
components (a), (b), and (c) are particularly useful in the production of 
multilayer printed circuits. 
Conventionally, a multilayer printed circuit is prepared from a number of 
double-sided printed circuit boards of copper, stacked one on top of 
another and separated from each other by insulating sheets, usually of 
glass fibre impregnated with a phenol-formaldehyde resin or an epoxide 
resin in the B-stage. The stack is 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 is therefore inherently weak and in 
use can become delaminated. It is therefore normal practice to remove the 
residual photopolymer after the etching stage, either by means of powerful 
solvents or by a mechanical method, e.g., by means of brushes. Such a 
stripping 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 compositions of 
this invention means that crosslinking can occur when the boards are 
bonded, resulting in good adhesion to the copper and to the 
resin-impregnated glass fibre substrate, so avoiding the necessity just 
referred to; also, products with a higher glass transition temperature are 
obtained. 
The compositions comprising components (a), (b), and (c) may also be used 
as adhesives. Employing irradiation to induce polymerisation, a layer of 
the composition may be sandwiched between two surfaces of objects, at 
least one of which is transparent to the actinic 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 two 
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. Manipulation 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 resin 
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 often exists without additional treatment, 
especially if polymerisation of the compositon 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 initiate polymerisation, a layer of the composition containing 
such a catalyst may be placed between, and in contact with, two surfaces 
to be joined, and the assembly is heated. Alternatively, a film adhesive 
may be made, but the 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 also 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, filaments, and whiskers), which may be in the 
form of woven or nonwoven cloth, unidirectional lengths, or chopped 
strands, especially glass, boron, stainless steel, tungsten, alumina, 
silicon carbide, asbestos, potassium titanate whiskers, an aromatic 
polyamide such as poly(m-phenylene isophthalamide), poly(p-phenylene 
terephthalamide) or poly(p-benzamide), polyethylene, or carbon. 
It is not necessary to convert immediately a polymerised composition, made 
from components (a), (b), and (c), distributed on the fibres into the 
fully crosslinked, insoluble, and infusible C-stage; often it can be 
changed into the still fusible B-stage, or remain in the A-stage, and, 
when desired, e.g., after stacking to form a multilayer laminate, and/or 
after the impregnated material has been formed into some desired 
configuration, fully crosslinked by heating (or further heating). For 
example, if a hollow shaped article is required, it is convenient to 
impregnate a continuous tow of fibrous reinforcement and wind the tow 
around a romer while, at the same time, exposing the winding to actinic 
radiation. Such windings still have a certain degree of flexibility, 
permitting the former to be removed more easily than when a rigid winding 
is formed in one step. When required, the so-called filament winding is 
heated to crosslink the composition and complete the cure. 
Alternatively, the composition comprising components (a), (b), and (c) may 
be made into a film adhesive as above, this film is 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 and the reinforcing effect thereby become irregularly 
distributed. 
For applying heat and pressure, heated platens or pairs of rollers may be 
used for example, and in the latter case, when unidirectional fibres are 
used, a rolling pressure may be applied in the direction in which the 
fibres are aligned. In place of pairs of rollers, the assembly may be 
passed under tension around the periphery 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 may, if desired, be laid on top, and then the assembly is 
pressed while being heated. It may also be made continuously, such as by 
containing the fibrous reinforcing material with the film of the 
polymerised composition, then, if desired, placing a second such film on 
the reverse face of the fibrous reinforcing material and applying heat and 
pressure. More conveniently, two such films, preferably supported on the 
reverse side belts or strippable sheets, are applied simultaneously to the 
fibrous reinforcing material so as to contact each exposed face. When two 
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 reinforcing materials. When 
unidirectional fibres are used as the reinforcement material, successive 
layers of them may be oriented to form crossply 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 material (e.g., an aromatic or 
aliphatic polyamide, a polyimide, a polysulphone, or a polycarbonate) or 
of a rubber (e.g., a neoprene or acrylonitrile rubber). 
In the production of sheet moulding compounds, a composition of this 
invention comprising components (a), (b), and (c), and, if used, the 
photoinitiator, together with the chopped strand reinforcing material and 
any other components, are exposed to irradiation in layers through 
supporting sheets. Alternatively, a free-radical catalyst may be employed, 
avoiding the use of a degree of heat that would cause thermal crosslinking 
until required. 
The polymerisable composition and, if used, the photoinitiator or the 
free-radical catalyst, are preferably applied so that the composite 
contains a total of from 20 to 80% by weight of the said components and, 
correspondingly, 80 to 20% by weight of the reinforcement. More 
preferably, a total of 30 to 50% by weight of these components and 70 to 
50% by weight of the reinforcement are employed. 
The compositions of this invention comprising component (a), (b), and (c) 
are also useful in the production of putties and fillers, and as 
dip-coating compositions, an article to be coated being dipped in a liquid 
composition of this invention and 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 components (d) and (e) are, as already indicated, 
useful for forming crosslinked coatings which usually have excellent 
adhesion to polar substrates such as metals, glass, and ceramics. 
The three component compositions may be supplied as two packs, one 
containing the unsaturated phenol (a) and the other the polymercaptan (b), 
the crosslinking agent (c) being contained in either or both packs. Of 
course, they may also be in the form of three component packs, one 
containing the phenol (a), a second the polymercaptan (b), and the third 
the crosslinking agent (c). When the two component compositions, i.e., 
those containing an at least dihydric phenol (d) and an at least 
trimercaptan (e), are required, these may likewise be marketed in two 
component packs, one containing component (d) and one containing component 
(e). Otherwise, the compositions may be stored as mixtures until required, 
protected from actinic radiation and sources of free radicals.

The following Examples illustrate the invention. Parts are by weight and 
temperatures are in degrees Celsius. 
Flexural strengths 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 determined 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-hydroxyphenyl)propane (228 g), sodium hydroxide (82.5 g), and 
n-propanol (1 liter) 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 under reflux for a further 
3 hours, the precipitated sodium chloride was filtered off, and the 
n-propanol was removed by distillation. The crude 
2,2-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 ether remaining 
was dried over sodium 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.degree.-205.degree.. The product was purified by heating it 
in a rotary evaporator and then by vacuum distillation (b.p. 
190.degree./0.5 mm). Microanalysis, gas chromatography, gel permeation 
chromatography, and NMR and IR-spectroscopy were used to confirm the 
structure of the intermediary diallyl ether and the rearranged product. 
Bis(3-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-hydroxyphenyl)propane was prepared as follows: 
2,2-Bis(3-allyl-4-hydroxyphenyl)propane (1 mole) was mixed with potassium 
hydroxide pellets (2.2 moles) and the mixture was stirred and heated at 
110.degree. for 30 minutes. The mixture was cooled, neutralised with 
dilute hydrochloric acid, and the product was extracted to give methylene 
chloride. The solution was dried and evaporated to give substantially pure 
2,2-bis(3-(1-propenyl)-4-hydroxyphenyl)propane. 
Proton NMR and IR-spectroscopy were used to confirm the assigned structure. 
More detailed studies using .sup.13 C NMR, however, showed the presence of 
minor amounts of isomeric material such as 
2-(3-(1-isopropenyl)-4-hydroxyphenyl)-2-(3-(1-isopropenyl)-2-hydroxyphenyl 
)propane, believed to be formed by thermal scission and recombination of 
the product. 
2,2-Bis(3,5-diallyl-4-hydroxyphenyl)propane was prepared by conversion of 
2,2-bis(3-allyl-4-hydroxyphenyl)propane into its diallyl ether and 
subjecting this to a Claisen rearrangement as described above. Its allyl 
double bond content was 10.3 equiv./kg. 
Rearrangement of 1,3-diallyloxybenzene afforded a mixture of the two 
isomeric phenols, 1,3-diallyl-2,4-dihydroxybenzene and 
1,5-diallyl-2,4-dihydroxybenzene. The mixture had an allylic double bond 
content of 10.53 equiv./kg. 
Bis(3-allyl-4-hydroxyphenyl) sulphone was prepared by rearrangement of 
bis(4-allyloxyphenyl) sulphone; its allylic double bond content was 6.71 
equiv./kg. 
The polymercaptans employed were commercially-available materials, having 
the following thiol contents: 
______________________________________ 
Polymercaptan SH-Equiv./kg 
______________________________________ 
Ethylene glycol dithioglycollate 
9.05 
Trimethylolpropane trithioglycollate 
8.0 
Pentaerythritol tetrathioglycollate 
8.8 
Tris(3-mercapto-2-hydroxypropyl ether) of 
a poly(oxypropylene)triol of average molecular 
weight 800 3.6 
Dipentaerythritol hexakis(3-mercaptopropionate) 
7.3 
A polysulphide of formula XXII, below 
2.0 
______________________________________ 
EXAMPLE 1 
Hexamine (5 parts) was dissolved in a mixture, warmed to 40.degree., 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), and benzil dimethyl acetal (4 parts). 
Glasscloth (plain weave, weighing 200 g/m.sup.2, with an epoxysilane 
finish) was impregnated at room temperature with this composition 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 nm waveband. A tack-free prepreg was obtained. 
Six 10-cm square pieces of the prepreg were stacked and heated at 
180.degree. for 1 hour under an applied pressure of 0.69 MN/m.sup.2, 
allowing a dwell time of 3 minutes before applying maximum pressure. The 
laminate was further heated at 180.degree. for 1 hour without applied 
pressure. It had a flexural strength of 265 MN/m.sup.2, and was composed 
of 57.2% of glass. 
EXAMPLE 2 
A liquid composition was prepared by stirring 
2,2-bis(3-allyl-4-hydroxyphenyl)propane (100 parts), trimethylolpropane 
trithioglycollate (81 parts, i.e., 1 allyl group equivalent per mercaptan 
group), benzil dimethyl acetal (4 parts), a polyglycidyl ether of a 
phenolformaldehyde 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-phenylimidazole (2 parts). This composition was coated onto 
a polyamide carrier film at room temperature and converted into a 
tack-free 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. 
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 acid solution ("Alclad" is a 
registered Trade Mark). Overlap joints of 1.27 cm were prepared by 
pressing the assembly under a pressure of 0.34 MN/m.sup.2 for 1 hour at 
180.degree.. The lap shear strength of the joints was 6.4 MN/m.sup.2. 
EXAMPLE 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 
MN/m.sup.2. 
EXAMPLE 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., 1 allyl group equivalent per mercaptan group, 5 
parts of hexamethylenetetramine, and 4 parts of 
2,2'-azobis(2-methylpropionitrile) as a layer 4 .mu.m thick on degreased 
and pickled aluminium sheets and heating for 1 hour at 80.degree. and then 
for one hour at 180.degree.. The coating was non-tacky, and was not 
affected by 20 rubs with an acetone-soaked cotton wool swab. 
EXAMPLE 5 
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 part of hexamethylenetetramine; it was applied 
similarly, and then cured by heating for 1 hour at 80.degree. and then 1 
hour at 180.degree.. The coating, which was not tacky, was unaffected by 
20 rubs with an acetone-soaked swab. 
EXAMPLE 6 
A liquid composition was prepared by stirring 
2,2-bis(3-(1-propenyl)-4-hydroxyphenyl)propane (100 parts), 
trimethylolpropane trithioglycollate (115 parts, i.e., 0.7 propenyl group 
equivalent 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/m.sup.2, with an epoxysilane 
finish) was impregnated at 40.degree. with this composition and then it 
was exposed on both sides for 30 seconds, at a distance of 15 cm, to a 400 
w high pressure 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 heated at 
170.degree. for 1 hour under an applied pressure of 0.69 MN/m.sup.2, 
allowing a dwell time of 3 minutes before applying maximum pressure. The 
laminate produced had a flexural strength of 226 MN/m.sup.2 and contained 
31.3% of glass. 
EXAMPLE 7 
A liquid composition was prepared by stirring 
2,2-bis(3-(1-propenyl-4-hydroxyphenyl)propane (100 parts), 
trimethylolpropane trithioglycollate (81 parts, i.e., 1 propenyl group 
equivalent per mercaptan group), benzil dimethyl acetal (4 parts), a 
polyglycidyl ether of a phenol-formaldehyde novolac as described in 
Example 2 (115 parts), and 2-phenylimidazole (2 parts). This 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 for 30 
seconds. 
Overlap joints were made from the film adhesive so obtained as described in 
Example 2: their lap shear strength was 5.3 MN/m.sup.2. 
EXAMPLE 8 
A surface coating was prepared by applying a mixture comprising 100 parts 
of 2,2-bis(3-(1-propenyl)-4-hydroxyphenyl)propane, 74 parts of 
pentaerythritol tetrathioglycollate, i.e., 1 propenyl group equivalent per 
mercaptan group, 5 parts of hexamethylenetetramine, and 4 parts of 
2,2'-azobis(2-methylpropionitrile) as a layer 6 .mu.m thick on degreased 
and pickled aluminium sheets and heating for 1 hour at 80.degree. followed 
by 1 hour at 180.degree.. The coating was tack-free and resisted more than 
20 rubs with an acetone-soaked swab. 
EXAMPLE 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 dimethyl acetal (1 part), and hexamine (0.5 part) 
was applied as a coating 6 .mu.m thick onto tinplate. The coating was 
irradiated with a 500 watt medium pressure mercury lamp at a distance of 
20 cm, and it was tack-free on 45 seconds' exposure. The coating was 
resistant to 11 rubs with an acetone-soaked cotton wool swab; on being 
heated for 1 hour at 180.degree. it was resistant to more than 20 such 
rubs. 
EXAMPLE 10 
A coating 6 .mu.m thick was applied to tinplate, consisting of a mixture of 
1,3- and 1,5-diallyl-2,4-dihydroxybenzene (10 parts), 52.6 parts of a 
mercaptan polysulphide of average formula 
EQU HS--(C.sub.2 H.sub.4 --O--CH.sub.2 O--C.sub.2 H.sub.4 --S--S--.sub.6 
C.sub.2 H.sub.4 --O--CH.sub.2 --O--C.sub.2 H.sub.4 --SH XXII 
i.e., 1 allyl group equivalent per mercaptan group equivalent, 1 part of 
benzil dimethyl acetal, and 0.5 part of hexamine. The coating was 
irradiated with a 1200 w medium pressure mercury lamp at a distance of 22 
cm; it became tack-free in 25 seconds, and resistant to 8 rubs with an 
acetone-soaked cotton wool swab. After being heated for 1 hour at 
180.degree. the coating withstood more than 20 such rubs. 
EXAMPLE 11 
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 polysulphide of formula XXII, i.e., 1 allyl group 
equivalent per mercaptan group. 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 cotton wool swab. After 
being heated at 180.degree. for 1 hour the coating withstood more than 20 
such rubs. 
EXAMPLE 12 
Benzophenone (10 parts) was dissolved in a mixture of 
2,2-bis(3-allyl-4-hydroxyphenyl)propane (100 parts) and pentaerythritol 
tetrathiolycollate (74 parts, i.e., 1 allyl group equivalent per mercaptan 
group). The liquid composition was applied as a coating 4 .mu.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 31/2 minutes' irradiation it had become almost 
completely cured, being resistant to 12 rubs with a cotton wool swab 
soaked in acetone. 
EXAMPLE 13 
Benzil dimethyl acetal (10 parts) was dissolved in a mixture of 
2,2-bis(3-allyl-4-hydroxyphenyl)propane (100 parts) and 179 parts of the 
tris(3-mercapto-2-hydroxypropyl) ether used in Example 9, i.e., 1 allyl 
group equivalent per mercaptan group. A coating was prepared as in Example 
12 and irradiated with a 1200 w medium pressure mercury lamp at a distance 
of 22 cm. After 10 seconds' irradiation the coating was tack-free, and 
after 25 seconds' irradiation it was resistant to 20 rubs with a cotton 
wool swab soaked in acetone. 
EXAMPLE 14 
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., 1 allyl group equivalent per mercaptan group, 
and 4 parts of 2,2'-azobis(2-methylpropionitrile) as a layer 4 .mu.m thick 
on degreased and pickled aluminium sheets and heating for 1 hour at 
80.degree.. The coating was non-tacky, and withstood 4 rubs with an 
acetone-soaked swab. 
EXAMPLE 15 
Benzophenone (10 parts) was dissolved in a mixture of 
2,2-bis(3-allyl-4-hydroxyphenyl)propane (100 parts) and dipentaerythritol 
hexakis(3-mercaptopropionate) (88.5 parts, i.e., 1 allyl group equivalent 
per mercaptan group). The liquid composition was applied as a coating 4 
.mu.m thick onto tinplate and irradiated under a 1200 w medium pressure 
mercury lamp at a distance of 22 cm. After 10 seconds the coating was 
tack-free and after 35 seconds it was resistant to 20 rubs with an 
acetone-soaked swab. 
EXAMPLE 16 
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., 1 propenyl group 
equivalent per mercaptan group). The liquid composition was applied as a 
coating and irradiated as in Example 15. After 5 seconds the coating had 
become tack-free, and after 25 seconds' irradiation it was resistant to 16 
rubs with a cotton wool swab soaked in acetone. 
EXAMPLE 17 
A mixture was prepared as in Example 13, using, however 100 parts of 
2,2-bis(3-(1-propenyl)-4-hydroxyphenyl)propane, i.e., 1 propenyl group 
equivalent per mercaptan group. A coating was prepared as in Example 12, 
applied at 40.degree., and irradiated as in Example 12. After 1 minute's 
irradiation, a flexible, tack-free coating was obtained. After 31/2 
minutes' irradiation the coating was resistant to 20 rubs with an 
acetone-soaked swab. 
EXAMPLE 18 
A surface coating was prepared by applying a mixture comprising 100 parts 
of 2,2-bis(3-(1-propenyl)-4-hydroxyphenyl)propane, 74 parts of 
pentaerythritol tetrathioglycollate, i.e., 1 propenyl group equivalent per 
mercaptan group, and 4 parts of 2,2'-azobis(2-methylpropionitrile) as a 
layer 6 .mu.m thick on degreased and pickled aluminium sheets and heating 
for 1 hour at 80.degree.. The coating was tack-free and resisted 10 rubs 
with an acetone-soaked swab. 
EXAMPLE 19 
Benzophenone (10 parts) was dissolved in a mixture of 
2,2-bis(3-allyl-4-hydroxyphenyl)propane (100 parts) and pentaerythritol 
tetrathioglycollate (140 parts, i.e., 0.5 allyl group equivalent per 
mercaptan group). The liquid composition was applied as a coating 6 .mu.m 
thick onto tin foil at room temperature and irradiated as in Example 12. 
After 90 seconds the coating had become tack-free and after 5 minutes' 
irradiation it had become almost completely cured, being resistant to 18 
rubs with a cotton wool swab soaked in acetone. 
EXAMPLE 20 
A composition was made as in Example 13 except that 107 parts of the 
mercaptan was used, i.e., 1.7 allyl group equivalents per mercaptan group. 
A coating was prepared as in Example 14, and after 31/2 minutes' 
irradiation a flexible, tack-free coating had been obtained. 
EXAMPLE 21 
The procedure of Example 14 was repeated, using, however, 140 parts of 
pentaerythritol tetrathioglycollate, i.e., 0.4 allyl group equivalent per 
mercaptan group. The coating was tacky, but withstood more than 20 rubs 
with an acetone-soaked swab. 
EXAMPLE 22 
A mixture of 2,2-bis(3,5-diallyl-4-hydroxyphenyl)propane (10 parts), 
trimethylolpropane trithioglycollate (12.9 parts, i.e., 1.0 allyl group 
equivalent per mercaptan group), and benzil dimethyl acetal (0.1 part) was 
applied as a layer 6 .mu.m thick onto tin foil and irradiated under a 500 
w medium pressure mercury lamp at a distance of 20 cm for 40 seconds, to 
give a tack-free coating.