Photosensitive material

Claim 1

A copolymer comprising: at most 75% by mole of a vinyl monomer copolymerizable with monomers (a) and (b), as defined below; at least 20% by mole of a monomer (a) having a perfluoroalkyl group or perfluoroalkenyl group at one end of the monomer and an ethylenically unsaturated group selected from the group consisting of acryloyloxy, methacryloyloxy, acryloylamino, methacryloylamino, vinyl ether and α-methylvinyl, at the other end of the monomer; a bivalent group containing --(CH 2 ) n -- linking the both end groups, monomer (a) is a compound having the following general formula (I): R.sub.f B.sub.m (CH.sub.2).sub.n --X--CR═CH.sub.2 (I) in which R f is a perfluoroalkyl group or perfluoroalkenyl group having 7 to 21 carbon atoms; B is a bivalent group linking the R f group and the --(CH 2 ) n -- group selected from the group consisting of --CO--, --SO 2 --, --O--, --(CH 2 ) 3 --O--, --S--, --(CH 2 ) p --NR 1 --, --CO--NR 1 --, --SO 2 --NR 1 --, ##STR29## wherein R 1 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and p is an integer of 1 to 6; R is hydrogen or methyl group; X is a single bond or a bivalent group selected from the group consisting of --O--, --OCO--, --COO--, --NHCO-- and --CO--; m is 0 or 1; and n is an integer of 1 to 10; and at least 5% by mole of an ethylenically unsaturated monomer (b) having a photosensitive group, wherein the photosensitive group is a member selected from the group consisting of: an azidobenzoyloxy group of the formula (1): ##STR30## in which Y is hydrogen, an alkyl group having 1 to 5 carbon atoms, an alkoxyl group having 1 to 5 carbon atoms, nitro group, chlorine or bromine, a cinnamic acid residue of the formula (2): ##STR31## a benzoylphenyl group of the formula (3): ##STR32## and a group containing an α,β-unsaturated ketone of the formula (4): --COCH═CH--(4) the photosensitive group containing the α,β-unsaturated ketone of formula (4) being selected from the group consisting of cinnamoylphenyl group of the formula: ##STR33## benzoylvinylphenyl group of the formula: ##STR34## ' -methoxy-4'-(1-buten-3-onyl)-phenyl group of the formula: ##STR35## benzoylvinylbenzoyloxy group of the formula: ##STR36## and a cinnamoyl group of the general formula: ##STR37## in which Y is as defined above.