Radiation sensitive sulfonium salts which contain (1) a sulfonium initiator portion, (2) a spacer portion, and (3) a reactive group portion. The spacer portion has the formula "-o-w- x-z-" wherein "w" is a single bond or one of --C(O)--, --C(O)O--, --C(O)S--, --C(O)NH-- --C(O)N(alkyl)--, --C(S)--, --C(S)S--,--S(O)--, --S(O)(O)--, or --S(O)(O)O--; "X" is an unsubstituted or substituted alkylene radical; and "Z" is --O--, --NH--, --N(C,--C.sub.6 -alkyl)--, or --N(phenyl)--. The reactive group portion is --CH.dbd.CH.sub.2 or --C(O)--C(Y).dbd.CH.sub.2 wherein "Y" is H, C.sub.1 -.sub.6 -alkyl, or phenyl. The sulfonium salts find use in curing monomers which can be subjected to cationic polymerization.

The present invention relates to novel radiation-sensitive, ethylenically 
unsaturated sulfonium salts and a process for their preparation. 
Sulfonium salts are used for curing monomers which can be subjected to 
cationic polymerization. Previously, the said monomers, for example 
epoxides, were cured using acidic catalysts, as described in U.S. Pat. No. 
3,842,019. For example, epoxides can be polymerized using boron 
trifluoride and its complexes, while styrene can be polymerized using 
aluminum trifluoride. Furthermore, 1,4-diazabicyclo[2.2.2]octane can be 
polymerized using benzenesulfonic acid. While the curing of such monomers 
with such catalysts gives successful results in many cases, acidic 
catalysts are often undesirable because catalysts of this type severely 
corrode various substrates, for example metals. In addition, many of these 
acidic catalysts do not have satisfactory stability as soon as they are 
mixed with the material to be polymerized. Furthermore, prior art 
catalysts, such as BF.sub.3 . NH.sub.2 C.sub.2 H.sub.5, are sensitive to 
moisture. 
According to U.S. Pat. No. 3,842,019, certain sulfonic acid salts which are 
exclusively thermally activated are used. However, these mixtures require 
curing temperatures of from 150.degree. to 200.degree. C. Such curable 
mixtures are unsuitable for the production of heat-sensitive electronic 
components. In particular cases, cationic curing of various compositions 
can be facilitated if a special photosensitive sulfonic acid salt, for 
example the corresponding silver salt, is used as the catalyst. However, 
the use of such metal sulfonate compositions is limited to special 
applications. 
DE-A-25 18 652 describes curable compositions which contain a polymerizable 
epoxy resin and a radiation-sensitive onium salt, such as triphenyl 
sulfonium hexafluoroantimonate. 
Onium salts are also used, inter alia, in microlithography for 
photochemical solubility differentiation. The special onium salts 
described in DE-A-27 54 853 eliminate, on exposure, a strong, 
nonnucleophilic acid, which serves for solubility differentiation of 
photopolymers (cf. for example Polym. Eng. Sci. 23 (1983), 953), in that 
an acid-labile protective group, for example the tert-butoxycarbonyloxy 
group (cf. Polymer 24 (1983), 995; Macromolecules 16 (1983), 510 and 
Polym. Eng. Sci. 23 (1983), 1022) is eliminated by the acid produced. 
Moreover, DE-A-37 21 740 describes sulfonium salts which contain one or 
more groups which can be eliminated by an acid. 
The onium salts are added to the monomer/polymer mixtures (cf. Chim. Nuov. 
4 (1986), 343). In general, however, such procedures are not entirely 
satisfactory since problems with the compatibility, the solubility, the 
uniformity, the distribution, the volatility, the odor, the toxicity, the 
exudation and the migration of the additive occur after mixing with the 
polymer, the said problems frequently leading to an undesirable, premature 
and nonuniform reaction In the actual exposure process, low reactivity is 
then observed owing to a reduced effective initiator concentration, and a 
number of troublesome side reactions are observed after exposure. 
Sulfonium salts are frequently used as initiators for the production of 
semiconductor photoresists. During application of the oligomer mixtures, 
dissolved in an organic solvent, to a substrate an increase in the 
concentration of the polar sulfonium salt in the lower regions of the 
polymer layer, in which regions the solvent remains longest, is frequently 
observed (cf. Macromolecules 16 (1983), 510) during evaporation of the 
solvent. This results in a photopolymer layer having an initiator 
concentration gradient which leads to poor, nonuniform curing results. 
From the chemistry of other photoinitiator classes, it is known that some 
of the stated problems can be solved if the radiation-sensitive initiator 
is copolymerized with monomers by a conventional process, i.e. is 
incorporated in a polymer chain. The photosensitive photoinitiator is 
attached to the base polymer by an anchor group, i.e. a spacer. The spacer 
also serves to reduce the influence of the base polymer chain on the 
photochemical behavior of the initiator. 
Copolymerizable initiators therefore have in principle the following 
structure: 
##STR1## 
A number of polymer-bound sulfonium salts, for example 
##STR2## 
(cf. Polymer 27 (1986), 1709), 
##STR3## 
(cf. EP-A-246 931) and 
##STR4## 
(cf. EP-A-246 931, Polym. Commun. 26 (1985), 362) where R, R' and R" are 
each alkyl, X is halogen and n is .gtoreq.5, have already been described. 
Sulfonium salts having ethylenically unsaturated, reactive groups are used 
as latent thermal catalysts 
##STR5## 
(cf. Makromol. Chem. Rapid Commun. 6 (1985), 137) or as copolymerizable 
monomers: 
##STR6## 
(cf. J. Polym. Sci., Part C, Polym. Lett. 26 (1988), 77). 
All polymer-bound sulfonium salts known to date are less toxic and form a 
smaller amount of volatile byproducts during photolysis than the 
corresponding monomeric onium salts. 
However, the abovementioned sulfonium salts are photochemically less 
reactive since the spacer is very short and in some cases completely 
absent. The onium group thus has little conformative mobility. 
It is an object of the present invention to provide novel copolymerizable 
sulfonium salts of the types 
##STR7## 
which do not have the abovementioned disadvantages and are particularly 
stable to migration. 
We have found that this object is achieved by radiation-sensitive, 
ethylenically unsaturated, copolymerizable, organic compounds of the 
general formula (I) 
EQU [(R).sub.a (R.sup.1).sub.b (R.sup.2).sub.c S.sup..sym. ]A.sup..crclbar.(I) 
where 
R is an unsubstituted or substituted monovalent aromatic organic radical, 
R.sup.1 is an unsubstituted or substituted monovalent organic aliphatic 
radical from the group consisting of the alkyl, cycloalkyl and substituted 
alkyl radicals, 
R.sup.2 is an unsubstituted or substituted divalent or trivalent aliphatic 
or aromatic organic radical which forms a heterocylic or fused ring 
structure, 
a is an integer from 0 up to and including 3, 
b is an integer from 0 up to and including 2, 
c is the integer 0 or 1, 
the sum a+b+c being 3, 
e is an anion of an acid and 
A.sup..crclbar. is an anion of an acid and 
at least one of the radicals R to R.sup.2 contains one of the radical 
##STR8## 
where W is a single bond or one of the groups 
##STR9## 
where alkyl is, for example, methyl, ethyl, n-propyl, isopropyl or 
n-butyl, and 
X is a divalent, unsubstituted or substituted alkylene radical 
--(CH.sub.2).sub.m --, a radical 
##STR10## 
where m is from 1 to 10 and R' and R" are identical or different and are 
each aryl, e.g. phenyl, C.sub.1 -C.sub.4 -alkyl, H, COOH, COOCH.sub.3 or 
COOC.sub.2 H.sub.5, or X is a perfluorinated alkylene radical 
--(CF.sub.2).sub.m --, where m is from 1 to 10, preferably a 
perfluoroethylene radical, for example a tetrafluoroethylene radical, an 
oxaalkylene radical of the type --(CH.sub.2).sub.n --O--(CH.sub.2).sub.p 
--, where n and p are each from 1 to 5, preferably 2, i.e. --C.sub.2 
H.sub.4 --O--C.sub.2 H.sub.4 --, a perfluorinated oxaalkylene radical of 
the type --(CF.sub.2).sub.n --O--(CF.sub.2).sub.p --, where n and p are 
each from 1 to 5, or a polyoxaalkylene radical which may be perfluorinated 
and has from 2 to 20 oxygen atoms which are bonded to one another by at 
least one --CH.sub.2 --, -- CF.sub.2 -- or --CH.sub.2 --CH(CH.sub.3)-- 
group, or an alkylene radical of the type --(CH.sub.2).sub.m 
--O--CO--O--(CH.sub.2).sub.n --, --(CH.sub.2).sub.n 
--O--CO--NH--(CH.sub.2).sub.m --, --(CH.sub.2).sub.n 
--NH--CO--O--(CH.sub.2).sub.m --, --(CH.sub.2).sub.m 
--CO--O--(CH.sub.2).sub.n --or --(CH.sub.2).sub.m 
--O--CO--(CH.sub.2).sub.n --, where m and n are each from 1 to 10, a 
phenylene radical which is unsubstituted or substituted by alkyl of 1 to 4 
carbon atoms, e.g. methyl, ethyl, n-propyl, isopropyl, OH, OCH.sub.3, 
OC.sub.2 H.sub.3, SH, SCH.sub.3, SC.sub.2 H.sub.5, Cl, F, N(alkyl).sub.2 
or N(CH.sub.3)C.sub.6 H.sub.5 in the o-, m- and/or p-position, or a 
cycloalkylene radical of 5 to 10 carbon atoms, e.g. cyclohexylene or 
cyclooctylene, or a (bis)methylenecycloalkylene radical of 6 to 12 carbon 
atoms, 
Y is H, alkyl of 1 to 6 carbon atoms or phenyl and Z is O or NY. 
Examples of R in the general formula (I) are unsubstituted or substituted 
C.sub.6 -C.sub.13 aromatic hydrocarbon radicals, such as phenyl, tolyl, 
4-(phenylthio)phenyl, naphthyl, anthryl, etc., and such aromatic 
hydrocarbon radicals substituted by 1 to 4 monovalent radicals, where the 
substituents may be C.sub.1 -C.sub.8 -alkoxy, C.sub.1 -C.sub.8 -alkyl, 
nitro, chlorine, hydroxyl, etc.; R may furthermore be arylalkyl, such as 
benzyl, phenacyl or an aromatic heterocyclic radical, such as pyridyl, 
furfuryl, etc. 
R.sup.1 includes C.sub.1 -C.sub.8 -alkyl, such as methyl, ethyl, etc., 
substituted alkyl, such as --C.sub.2 H.sub.4 OCH.sub.3, --CH.sub.2 
COOC.sub.2 H.sub.5, --CH.sub.2 COCH.sub.3, etc. 
The radicals R.sup.2 include structures such as 
##STR11## 
The anions A.sup..crclbar. in formula (I) are, for example, 
BF.sub.4.sup..crclbar., PF.sub.6.sup..crclbar., AsF.sub.6.sup..crclbar., 
SbF.sub.6.sup..crclbar., ClO.sub.4.sup..crclbar., CF.sub.3 
SO.sub.3.sup..crclbar., AlCl.sub.4.sup..crclbar., BCl.sub.4.sup..crclbar., 
Br.sup..crclbar., Cl.sup..crclbar., HSO.sub.4.sup..crclbar., CH.sub.3 
CO.sub.2.sup..crclbar., NO3.sup..crclbar., etc. and 
(MSO.sub.3).sup..crclbar., where M is selected from the group consisting 
of the aromatic C.sub.1 -C.sub.13 -hydrocarbon radicals, C.sub.1 -C.sub.8 
-alkyl radicals, their halogenated derivatives and fluorine. 
Surprisingly, the novel compounds have particularly high photochemical 
reactivity both in the short-wavelength UV range of 250-350 nm and in the 
longer wavelength range of 330-430 .mu.m, depending on their substitution 
pattern. 
It is a further object of the present invention to provide a process for 
the preparation of novel, radiation-sensitive, copolymerizable sulfonium 
salts having at least one acrylate or vinyl ether terminal group. 
We have found that this object is achieved by reacting hydroxyl-containing 
sulfonium salts with isocyanates or chloroformates or their thermally 
stable intermediates in the presence or absence of a catalyst. 
We have found, surprisingly, that the novel sulfonium salts are obtainable 
readily and in very good yield. This is particularly unexpected in view of 
the reactivity and bifunctionality of the (meth)acrylate, vinyl ether and 
isocyanate component, since many different reaction products are possible. 
The present invention furthermore relates to a process for the preparation 
of compounds of the general formula (I), wherein a compound of the formula 
(II), (III) or (IV) 
##STR12## 
where W, X, Y and Z have the abovementioned meanings and 
B is one of the groups tosylate, alkoxy of 1 to 5 carbon atoms, halogen, eg 
Cl or Br, chlorocarbonyl, imidazolyl, pyrazolyl or an ammonium, 
pyridinium, phosphonium or sulfonium cation, preferably, for example, a 
2-(acryloyloxyethyl) or 2-(methacryloyloxyethyl)chlorocarbonate, a 
2-(methacryloyloxyethyl}chloroglyoxylate or a 
(2-(meth)acryloyloxyethyl)methyl carbonate, is reacted with a compound of 
the general formula (V) 
EQU [(R).sub.a (R.sup.1).sub.b (R.sup.2).sub.c S.sup..sym. ]A.sup..crclbar.(V) 
where 
R is an unsubstituted or substituted monovalent aromatic organic radical, 
R.sup.1 is an unsubstituted or substituted monovalent organic aliphatic 
radical from the group consisting of the alkyl, cycloalkyl and substituted 
alkyl radicals, 
R.sup.2 is an unsubstituted or substituted divalent or trivalent aliphatic 
or aromatic organic radical which forms a heterocylic or fused ring 
structure, 
a is an integer from 0 up to and including 3, 
b is an integer from 0 up to and including 2, 
c is the integer 0 or 1, 
the sum a+b+c being 3, and 
A.sup..crclbar. is an anion of an acid and 
at least one of the radicals R to R.sup.2 contains a hydroxyl group, for 
example 
##STR13## 
in an equimolar ratio (if necessary with up to 10-30% excess) or, 
depending on the number of hydroxyl groups in the radicals R to R.sup.2, 
in two or three times the equimolar ratio, in the presence or absence of 
an inert solvent or solvent mixture and of a basic catalyst, at from 
0.degree. to 100.degree. C., preferably from 10.degree. to 60.degree. C. 
Some chloroformates used in the reaction and the isocyanates react readily 
with nucleophiles, including water. It is therefore important to carry out 
the reaction in the absence of moisture by using dry and/or weakly 
nucleophilic or nonnucleophilic solvents, eg. acetonitrile, 
dichloromethane, dichloroethane, tetrahydrofuran, toluene, xylene, 
chlorobenzene, ethyl acetate, chloroform, etc., and if necessary to 
establish an inert gas atmosphere, for example nitrogen, argon or carbon 
dioxide. 
The syntheses of the hydroxysulfonium salts required as starting materials 
are known. The following references may be stated as examples: 
J. Am. Chem. Soc. 80 (1958), 3425; 
J. Polym. Sci. Polym. Chem. Ed. 18 (1980), 1021; 
Polym. Prep. Am. Chem. Soc. Div. Polym. Chem. 25 (1984), 262; 
Polym. J. 17 (1985), 73; U.S. Pat. Nos. 4,336,363, 4,417,061, 4,650,734 and 
4,684,671; European Patent 245,662; Japanese Patent 61,212,555; German 
Laid-Open Application DOS 1,951,803; German Patent 2,541,709, etc., and 
the literature cited herein. 
The .omega.-(meth)acryloyloxyalkyl chloroformates can be prepared 
conveniently and in good yields by processes known in the literature, as 
described in, for example, Eur. Polym. 14 (1978), 205; J. Polym. Sci. 
Polym. Symp. 66 (1979), 41 and Bull. Soc. Chim. Belg. 93 (1984), 159. 
Examples of compounds of this type are: 
##STR14## 
Other methods for the preparation of the chloroformates, which are 
particularly suitable for laboratory syntheses, are arrived at through the 
choice of the phosgenating agents. Examples of alternative phosgenating 
agents are trichloromethyl- chloroformate (diphosgene), J. Prakt. Chem. 
126 (1930), 210, ibid 128 (1930), 233, Chem. Abstr. 95, 81766, J. Org. 
Chem. 50 (1985), 715, J. Org. Chem. 41 (1976), 2070, Angew. Chem. 89 
(1977), 267, crystalline triphosgene, Angew. Chem. 99 (1987), 922, 
N,N'-carbonyldiimidazole or N,N'-carbonyldi-s-triazole (Fieser 1 (1967), 
116). 
For example, the following can be prepared with the aid of these reagents: 
##STR15## 
Merck Kontakte 1981 (1), 1-18 gives information about the use of further 
special alternative processes for phosgenation, for example reaction with 
chlorocarbonates. 
The reaction of p-hydroxyphenylphosphonium salts with activated acyl 
chlorides is described in EP-A-245 662. The following compounds 
##STR16## 
are prepared from the corresponding acid chlorides or chloroformates. The 
sulfonium salts are very reactive; they are used in the form of activated 
esters in peptide synthesis. It is surprising that the chloroformates of 
the hydroxyalkyl (meth)acrylates are stable to nucleophiles and in some 
cases can even be recrystallized from isopropanol. These properties make 
them particularly interesting for use in polymers having nucleophilic 
groups. 
The .omega.-isocyanatoalkyl (meth)acrylates can be synthesized in good 
yield by the processes described in EP-A-083 764 and DE-A-35 23 692. The 
following isocyanates are examples: 
##STR17## 
Other isocyanates are obtained in a conventional manner, for example by the 
process of U.S. Pat. No. 2,718,516, in which an alkanolamine is reacted 
with ethyl chloroformate, the resulting hydroxyalkyl ethyl carbonate is 
acylated with methacryloyl chloride and the resulting urethane is cleaved 
in the presence of a basic catalyst with heating, or by the process of 
U.S. Pat. No. 2,821,544, in which methacryloyl chloride is also reacted 
with an alkanolamine hydrochloride and the resulting .omega.-aminoalkyl 
methacrylate is then reacted with phosgene. Examples of suitable 
alkanolamine hydrochlorides are: 
##STR18## 
The literature contains similar examples for the reaction of the 
hydroxy(aryl)sulfonium salts with the isocyanates to give the 
corresponding aryl carbamates. 
The synthesis of aryl carbamates without copolymerizable terminal groups is 
known C. Ferri, Reaktionen der organischen Synthese, G. Thieme Verlag, 
Stuttgart, 1978, gives an overview. 
The most important preparation process is the reaction of aromatic alcohols 
with isocyanates (cf. Houben-Weyl VIII, page 141; O. S. Petersen, Liebigs 
Ann. Chem. 562 (1947), 205; J. Burkus, J. Org. Chem. 26 (1961), 779; I. T. 
Kay and N. Punja, J. Chem. Soc. [C] 1968, 3011; L. Capuano and R. Zander, 
Chem. Ber. 104 (1971), 2212). The carbamates are formed in good to very 
good yields when an alcohol and an isocyanate are reacted with one another 
in a molar ratio of 1:1 without a solvent or in excess alcohol as the 
solvent Where the alcohol or the phenol is in the form of a solid, an 
aprotic solvent, eg. dichloromethane, dichloroethane, acetonitrile, 
toluene, etc., is used. 
In extrapolating this preparation process to .omega.-isocyanatoalkyl 
(meth)acrylates of the general formula (IV), where X is an alkylene 
radical which may be perfluorinated, an oxaalkylene radical or a 
polyoxaalkylene radical, each of 2 to 12 carbon atoms, and Y is H-- or 
CH.sub.3 --, we have found, surprisingly, that the desired 
carbamoyl-substituted sulfonium salts having (meth)acrylate groups are 
formed in a high, virtually quantitative yield. This is surprising in that 
acrylates and methacrylates can readily undergo many side reactions 
(crosslinking, polymerization). 
The good to excellent yields in the presence of sulfonium groups are also 
surprising. 
Regarding the preparation process, the following may be stated 
specifically: 
As a rule, a solution or suspension of the hydroxy compound in an inert 
solvent, which may also be omitted if the compound is liquid at the 
reaction temperature, is initially taken at from 0.degree. to 100.degree. 
C., preferably from 10.degree. to 60.degree. C., in the presence of a 
basic, weakly nucleophilic or nonnucleophilic amine, preferably 
triethylamine, 4-dimethylaminopyridine, imidazole, 
1,4-diazabicyclo[2.2.2]octane, 1,5-diazabicyclo[4.3.0]non-5-ene, 
1,8-diazabicyclo[5.4.0]undec-7-ene, polyvinylpyridine, 
N,N-dimethylpropyleneurea, N,N'-dimethylethyleneurea, etc. Then, for 
example, the chloroformyl compound, which may be dissolved in an inert 
solvent, eg. dichloromethane, dichloroethane, acetonitrile, toluene, 
chlorobenzene, xylene, etc., is added dropwise with stirring in the 
abovementioned temperature range. This procedure is particularly suitable 
for relatively large batches. 
After stirring has been continued for from 1 to 48, preferably from 1 to 
20, hours at from 10.degree. to 30.degree. C., filtration, washing and 
drying are carried out by standard methods and the product is isolated 
after recrystallization, distillation or extraction. 
The present invention also relates to cationically curable mixtures which 
contain a novel copolymerizable sulfonium salt as the catalyst, can be 
cured by heating or exposure to actinic light and are suitable for the 
production of moldings, coatings, relief images and resist patterns. 
Cationically curable mixtures, such as epoxy resins, are usually cured 
using carboxylic acids or anhydrides thereof or by the addition of other 
Lewis acids. Because of the high reactivity, the two components must be 
handled separately and processed rapidly after mixing. There has been no 
lack of attempts to develop single-component systems which have a longer 
shelf life and can be cured either by heating or by exposure to light of a 
suitable wavelength. Many photoinitiators have been described as catalysts 
for light-induced curing, including in particular the diazonium salts of 
U.S. Pat. Nos. 3,205,157 and 3,708,296 and the onium salts of the elements 
of main groups V (cf. DE-A-2 518 656), VI (cf. DE-A-2 518 652 and DE-A-904 
626) and VII (cf. DE-A-2 518 639) of the Periodic Table of the Elements 
and the sulfoxonium salts stated in EP-A-22 081, EP-A-35 969 and EP-A-44 
274. However, these compounds have unsatisfactory properties On exposure, 
diazonium salts release nitrogen, which may lead to bubble formation in 
the moldings and coatings produced using diazonium salts. The iodonium 
salts of DE-A-2 518 639 are toxic; like the sulfonium salts of DE-A-2 518 
652 and DE-A-2 904 626, they furthermore absorb only weakly in the 
wavelength range of 300-400 nm, so that in general a sensitizer has to be 
added to the photocurable mixture. Furthermore, some of the sulfonium 
salts according to DE-A-2 518 652 and DE-A-2 904 626 release foul-smelling 
low molecular weight sulfur compounds on exposure to actinic light. The 
sulfoxonium salts of EP-A-22 081, EP-A-35 969 and EP-A-44 274 can only be 
obtained by an involved procedure using expensive organometallic reagents, 
which makes them more difficult to produce in industrial amounts. 
DE-A 2 853 886 describes, as a catalyst for heat-curable systems, a 
combination of an iodonium salt and a Cu.sup.I salt, which however can 
only be used with considerable safety measures, owing to the highly toxic 
iodonium salt. Another catalyst combination is the mixture of pyrylium 
salts and metal chelates, described in DE-A 3 135 636; however, the shelf 
life of the mixtures prepared with the aid of this initiator combination 
is unsatisfactory 
It is a further object of the present invention to provide cationically 
curable mixtures which contain a cationic curing catalyst, have a long 
shelf life, are easy to handle, can be processed and are non-toxic and 
which give moldings having a good surface and solvent resistance after 
curing. 
The novel curable compositions contain, for example, 
a) a compound or a mixture of compounds which can be converted into a 
higher molecular weight material under the influence of a cationic 
catalyst and 
b) preferably 0.1-15% by weight, based on the amount of the compounds a), 
of the novel sulfonium salts described above. 
The compounds a) may be, for example, oxetanes, thiiranes or 
tetrahydrofuran. Compound a) is preferably a 1,2-epoxide, an olefinically 
unsaturated compound, an aminoplast or a phenoplast, provided that they 
are cationically curable or polymerizable 
Examples of suitable 1,2-epoxides are epichlorohydrin, propylene oxide and 
glycidyl ethers of a monohydric alcohol or of a phenol, such as n-butyl 
glycidyl ether or phenyl glycidyl ether, and glycidyl esters, such as 
glycidyl acrylate or glycidyl methacrylate. Component a) is preferably an 
epoxy resin, in particular one which contains at least one group of the 
formula (VI) 
##STR19## 
which is bonded directly to an oxygen atom and in which either R.sup.3 and 
R.sup.5 are each hydrogen, in which case R.sup.4 is hydrogen or methyl, or 
R.sup.3 and R.sup.5 together form --CH.sub.2 CH.sub.2 --, in which case 
R.sup.4 is hydrogen. Examples of such resins are polyglycidyl and 
poly(.beta.-methylglycidyl) esters, which can be obtained by reacting a 
compound containing two or more carboxylic acid groups with 
epichlorohydrin, glycerol dichlorohydrin or .beta.-methylepichlorohydrin 
in the presence of an alkali. Such polyglycidyl esters may be derived from 
aliphatic polycarboxylic acids, such as succinic acid, glutaric acid, 
adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid or 
dimerized or trimerized linoleic acids, cycloaliphatic polycarboxylic 
acids, such as tetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 
hexahydrophthalic acid and 4-methylhexahydrophthalic acid, and from 
aromatic polycarboxylic acids, such as phthalic acid, isophthalic acid and 
terephthalic acid. Other suitable polyglycidyl esters are obtainable by 
polymerization of the glycidyl esters of olefinically unsaturated acids, 
in particular of glycidyl acrylate and glycidyl methacrylate. 
Polyglycidyl and poly(.beta.-methylglycidyl) ethers, such as those which 
are obtainable by reacting a compound containing at least two free 
alcoholic and/or phenolic hydroxyl groups in the molecule with the 
corresponding epichlorohydrin under alkaline conditions, or in the 
presence of an acidic catalyst with subsequent treatment with an alkali, 
are also suitable. Examples of alcohols and phenols for such a reaction 
are ethylene glycol, propanediol, diethylene glycol, poly(oxyethylene) 
glycols, poly(oxypropylene) glycols, poly(oxytetramethylene) glycols, 
glycerol, 1,1,1-trimethylolpropane, pentaerythritol, sorbitol, 
bis-(4-hydroxycyclohexyl)-methane, 2,2-bis-(4-hydroxycyclohexyl)-propane, 
N,N-bis-(2-hydroxyethyl)aniline, 
p,p'-bis-(2-hydroxyethylamino)diphenylmethane, 
bis-(4-hydroxyphenyl)propane and novolaks, such as can be prepared by 
reacting aldehydes, such as formaldehyde or acetaldehyde, with phenols. 
Examples of epoxy resins with groups of the formula VI, where R.sup.3 and 
R.sup.5 together form a --CH.sub.2 CH.sub.2 -- group, are 
bis-(2,3-epoxycyclopentyl) ether or 2,3-epoxycyclopentyl glycidyl ether. 
Epoxy resins in which some or all of the epoxide groups are in the middle, 
such as vinylcyclohexene dioxide and dicyclopentadiene dioxide, and 
epoxidized polybutadienes or epoxidized butadiene copolymers with vinyl 
monomers can also be used. It is of course also possible to use epoxy 
resin mixtures. 
Particularly preferably used epoxy resins are the diglycidyl ethers of 
dihydric phenols and of dihydric aliphatic alcohols. 
If desired, the epoxy resin may also be subjected in a known manner to 
cocuring with a polyhydric alcohol, in particular one having a molecular 
weight of more than 1,000. Examples of suitable alcohols for this purpose 
are poly(oxyethylene) glycols, polyvinyl alcohols, hydroxypropylcellulose 
and partial esters of cellulose. 
Olefinically unsaturated monomers a) which can be subjected to cationic 
polymerization with the novel sulfonium salts are, for example, styrene, 
.alpha.-methylstyrene, divinylbenzene, vinylcyclohexane, 
4-vinylcyclohex-1-ene, N-vinylcarbazole, isoprene, butadiene and 
preferably vinyl ethers, such as methyl vinyl ether, isobutyl vinyl ether, 
1,1,1-trimethylolpropane trivinyl ether, glycerol trivinyl ether, the 
vinyl ethers of ethylene glycol and polyethylene glycols and cyclic vinyl 
ethers. 
The aminoplasts as preferred components a) contain, per molecule, at least 
two methylol groups which are bonded to an amide or thioamide nitrogen 
atom or atoms and may also be etherified or esterified. Examples of such 
aminoplasts are the N-hydroxymethyl, N-methoxymethyl, N-butoxymethyl and 
N-acetoxymethyl derivatives of urea, thiourea or cyclic ureas, of 
carbamates and dicarbamates of aliphatic monohydric and dihydric alcohols 
and of melamine, such as partially etherified hexamethylolmelamine, and of 
other polyamino-1,3-triazines. Preferred aminoplasts are the condensates 
of urea, of hydantoin or of melamine with formaldehyde, for example a 
condensate of urea with 1.8 moles of formaldehyde, and partially or 
completely etherified products of such condensates with an aliphatic 
monohydric alcohol of 1 to 4 carbon atoms, such as 
hexamethoxymethylmelamine. 
Preferred phenoplasts are the known resols prepared from a monohydric or 
polyhydric phenol and an aldehyde, such as formaldehyde Suitable 
additives, such as diluents, reinforcing agents, fillers, dyes, pigments, 
processing assistants and other conventional additives, the type and 
amount of which are familiar to the skilled worker, may be added to the 
novel curable mixtures. 
The curable resin compositions prepared with the aid of the novel sulfonium 
salts may furthermore contain, as an additional component, for 
accelerating the curing, an oxidizing agent from the class consisting of 
the quinones and of the organic peroxides. Suitable compounds are, for 
example, ketone peroxides, peroxy acids, aldehyde peroxides, 
hydroperoxides, especially alkyl peroxides, diacyl peroxides and alkyl 
esters of per acids, for example butyl peroxypivalate, benzoyl peroxide, 
di-tertbutyl peroxide, tert-butyl hydroperoxide, methyl ethyl ketone 
peroxide and m-chloroperbenzoic acid. Examples of suitable quinones are 
the benzoquinones which are completely or partially substituted by 
chlorine or cyano, such as chloranil or 
2,3-dichloro-5,6-dicyanobenzoquinone. 
The novel curable mixtures contain in general from 0.1 to 15, preferably 
from 0.5 to 10, % by weight of the novel sulfonium salts and, if required, 
0.01-10, preferably 0.05-2, % by weight of the abovementioned oxidizing 
agent, the percentages in each case being based on the total amount of the 
curable compounds a). 
The novel mixtures can be cured by heating or by exposure to actinic light 
of wavelength 200-600 nm, the optimum curing method depending on the 
components used in the mixtures and on the intended use of the latter. The 
novel compositions preferably also contain a sensitizer. We have found 
that incorporation of suitable sensitizers further increases the curing 
rate, permitting the use of even shorter exposure times and/or less 
powerful radiation sources. Furthermore, the sensitivity to visible light 
is increased. Suitable sensitizers are acetophenone derivatives, such as 
benzil dimethyl ketal or benzoin ethers, benzophenone or its derivatives 
and thioxanthone derivatives, such as 2-methyl- or 
2-isopropylthioxanthone. Other suitable sensitizers are polycyclic 
aromatics, such as anthracene, phenanthrene, rubrene, perylene and pyrene 
0.1-2% by weight, based on the total amount of components a), of 
sensitizers are preferably employed. 
Suitable actinic radiation sources for photocuring at wavelengths of 
200-600 nm are the known ones, such as carbon arc lamps, mercury vapor 
lamps, fluorescent tubes emitting ultraviolet light, argon and xenon glow 
lamps and photographic floodlights. The time required for exposure depends 
on, inter alia, the polymerizable material used and the type of light 
source and its distance from the exposed material and can readily be 
determined by the skilled worker in a preliminary test. 
If the curable compositions is to be heat-cured, it is brought into a 
suitable form, for example cast as a thin film. For curing, the resin is 
heated to 80.degree.-160.degree. C., preferably 100.degree.-150.degree. C. 
The novel compositions can be used, for example, for surface coatings and 
can be cured by exposure or heating after application to a substrate, such 
as steel, aluminum, copper, cadmium, zinc, paper or wood. If exposure is 
effected through a mask, the unexposed parts of the layer can be removed 
by washing out. The novel mixtures are particularly suitable for the 
production of printing plates and printed circuits, and the known methods 
for the production of printing plates and printed circuits from 
photopolymerizable compositions can be used. 
The novel mixtures can also be used as adhesives, for the production of 
fiber-reinforced composite materials, including sheet molding compounds, 
for the production of cements and filling compounds or for dip coating. 
A novel mixture containing, for example, an epoxy resin or phenoplast and 
an amount of the novel sulfonium salt which is effective during exposure 
of the composition to actinic radiation for polymerization of this epoxy 
resin or phenoplast may also contain an effective amount of a latent 
heat-curing agent for the epoxy resin or phenoplast, such as 
polycarboxylic anhydrides, complexes of amines, in particular primary or 
tertiary aliphatic amines, with boron trifluoride or boron trichloride . 
Latent crosslinking agents for resols include hexamethylenetetramine and 
paraformaldehyde. The temperature and heating time required for heat 
curing and the amounts of heat-activatable curing agents can readily be 
determined in a known manner by preliminary tests. 
A particular use of the mixtures according to the invention, containing 
novel copolymerizable sulfonium salts, is in the form of a photosensitive 
recording material for the production of relief images or resist patterns 
with a photosensitive curable layer applied to a dimensionally stable 
substrate. 
We have found that the sulfonium salts used in novel mixtures are very 
suitable as heat-activatable and photochemically activatable catalysts for 
the photochemical elimination of phenolic protective groups and hence for 
solubility differentiation. Regarding further information on this use of 
the novel mixtures for such recording materials, reference may be made to 
DE-A-33 26 036, DE-A-32 31 147 and DE-A-32 31 145. The use of novel 
sulfonium salts of the formula (I) imparts to such recording materials a 
long shelf life coupled with a short post-curing time and in particular a 
uniform distribution of the initiator in the layer. For example, they can 
be stored for several weeks at 50.degree. C. without any deterioration in 
the very good properties of the recording materials and in the high 
quality of the relief images or resist patterns produced therefrom. 
Novel photosensitive recording materials are suitable for the production of 
letterpress, gravure, offset or screen printing plates, photoresists and 
soldering masks. They are also useful for laminating materials in the 
production of circuit boards, printed circuits, integrated circuits, etc. 
The production of relief images or resist patterns by means of the novel 
recording materials containing sulfonium salts can be carried out 
alternatively by the negative-working or positive-working method, as known 
per se and described in, for example, DE-A 23 09 062, DE-A 32 31 144, DE-A 
32 31 145 and DE-A 32 31 147. 
For all the compounds stated in the Examples below, the structure was 
confirmed by correct .sup.1 H-NMR, IR and mass spectra and by conforming 
elemental analyses. 
In the Examples, percentages are by weight.

EXAMPLE 1 
4-(N-(Methacryloylethyl)-carbamoyl)-phenyldimethylsulfonium 
hexafluoroarsenate 
42.5 g of isocyanatoethyl methacrylate were added dropwise to a solution of 
86 g of 4-hydroxyphenyldimethylsulfonium hexafluoroarsenate in 870 g of 
toluene and 443 g of tetrahydrofuran at room temperature. A solution of 3 
g of triethylamine in 89 g of tetrahydrofuran was then added in the course 
of 10 minutes at an internal temperature of from 23.degree. to 26.degree. 
C., and the reaction mixture was stirred overnight at room temperature. 
The precipitated crystals were filtered off under suction, washed with 
toluene and recrystallized from ethanol. Yield: 110 g (88%) of colorless 
crystals of melting point 95.degree.-97.degree. C. 
EXAMPLE 2 
4-(N-(Methacryloylethyl)-carbamoyl)-phenyldimethylsulfonium 
hexafluorophosphate 
A solution of 3 g of triethylamine in 89 g of tetrahydrofuran was added 
dropwise to a mixture of 870 g of toluene, 443 g of tetrahydrofuran, 90 g 
of 4-hydroxyphenyldimethylsulfonium hexafluorophosphate and 51 g of 
isocyanatoethyl methacrylate at from 20 to 25.degree. C. in the course of 
10 minutes, at a rate such that there was no marked temperature increase 
After 12 hours, the product was filtered off under suction, washed with 
toluene and recrystallized from ethanol. Yield: 112 g (82%) of colorless 
crystals of melting point 102.degree.-104.degree. C. 
EXAMPLES 3 to 8 
The following sulfonium salts were prepared by a method similar to those 
stated in Examples 1 and 2: 
__________________________________________________________________________ 
Example No. 
Compound Anion 
Yield [%] 
__________________________________________________________________________ 
##STR20## AsF.sub.6.sup..crclbar. 
89 
4 
##STR21## SbF.sub.6.sup..crclbar. 
62 
5 
##STR22## PF.sub.6.sup..crclbar. 
77 
6 
##STR23## AsF.sub.6.sup..crclbar. 
84 
7 
##STR24## PF.sub.6.sup..crclbar. 
80 
8 
##STR25## PF.sub.6.sup..crclbar. 
73 
__________________________________________________________________________ 
EXAMPLE 9 
4-(1-Methacryloylethylcarbonato)-naphthyl)-tetrahydrothiophenium chloride 
A mixture of 533 g of 4-(1-hydroxynaphthyl)tetrahydrothiophenium chloride 
and 540 g of hexamethyldisilazane was boiled for 8 hours at 100.degree. C. 
in the absence of moisture. The mixture was cooled to room temperature, 
after which excess silazane was distilled off under reduced pressure from 
an oil pump and the residue (680 g) was dissolved in 2,300 g of 
acetonitrile. After the addition of 385 g of 2-chloroformylethyl 
methacrylate, heating was carried out for 5 hours at room temperature and 
for 5 hours under reflux. Chromatographic separation (silica gel/toluene) 
gave 4.8 g (57%) of a yellowish oil, which was pure according to .sup.1 
H-NMR and .sup.13 C-NMR spectroscopy. 
EXAMPLES 10 TO 17 (including Comparative Examples) 
Surface coatings 
The salts below were added as catalysts to 15% strength solutions of 
bisphenol A diglycidyl ether in acetone, in amounts such that the 
proportion of catalyst in each case was 3%, based on the bisphenol A 
diglycidyl ether. 
The photosensitive mixtures prepared without heating were applied to glass 
sheets using an 80 .mu.m knife coater (effective film thickness about 50 
.mu.m), dried in the air for 5 minutes to remove the acetone before 
exposure and conveyed past two lamps of 80 W/cm power in the air at a 
distance of about 10 cm at the belt speed stated in each case. The exposed 
films were evaluated immediately after exposure, after 2 hours and after 1 
day, in accordance with the following quality characteristics: 
______________________________________ 
Gelled: No longer free-flowing, tacky 
Solid: Surface non-tacky but without finger- 
nail hardness 
Completely cured: 
Non-tacky, possesses fingernail hard- 
ness. 
______________________________________ 
TABLE 1 
__________________________________________________________________________ 
Curing of the surface coating 
Curing result 
Example Belt speed 3 m/min 
No. Compound Immediately 
After 2 hours 
After 1 
__________________________________________________________________________ 
day 
10* 
##STR26## Completely cured 
Completely cured 
Completely cured 
11* 
##STR27## Solid Completely cured 
Completely cured 
12 
##STR28## Completely cured 
Completely cured 
Completely cured 
13 
##STR29## Completely cured 
Completely cured 
Completely 
__________________________________________________________________________ 
cured 
*Comparative Examples 
TABLE 2 
__________________________________________________________________________ 
Curing of the surface coating 
Curing result 
Example Belt speed 15 m/min 
No. Compound Immediately 
After 2 hours 
After 1 
__________________________________________________________________________ 
day 
14* 
##STR30## Solid Solid Completely cured 
15* 
##STR31## Gelled Solid Solid 
16 
##STR32## Solid Solid Completely cured 
17 
##STR33## Solid Solid Completely 
__________________________________________________________________________ 
cured 
*Comparative Examples 
As shown by the results stated in Tables 1 and 2, the novel mixtures of 
Examples 12, 13, 16 and 17 are as good as or better than those of the 
Comparative Examples, which, in Examples 10 and 14, contain a toxic 
catalyst salt. 
With the aid of ESCA measurements, it is possible to show that the 
triarylsulfonium hexafluorophosphate (Comparative Examples 11 and 15) has, 
in the film, a concentration gradient which increases toward the substrate 
and is responsible for the poorer curing.