Polymerizable esters

Claim 1

An ester as a composition of matter, which is soluble in an aqueous solution of a base before exposure to actinic radiation, but which polymerizes on exposure to actinic radiation and becomes insoluble in said aqueous solution, which comprises the condensation product of (A) the reaction product of (1) a phenol of the formula ##STR17## each R represents a halogen atom, an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkoxy, alkenoxy, carbalkoxy, carbalkenoxy, carbocycloalkoxy, or carbocycloalkenoxy group of 1 to 9 carbon atoms or a nitro group, each a represents zero or an integer of 1 to 4, R 2 and R 3 individually are each a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, or a phenyl group, or conjointly denote a polymethylene chain of 2 to 4 methylene groups, d and e are each zero, 1, or 2, with the proviso that they are not both zero, and (2) a compound containing a 1,2-epoxy group selected from the group consisting of ethylene oxide, propylene oxide and epichlorohydrin, said phenol (1) and 1,2-epoxy compound (2) being reacted at a temperature of 80° to 150° C. in the presence of an inert solvent, a free-radical polymerization inhibitor and a ring opening catalyst selected from the group consisting of a tertiary amine and a quaternary ammonium compound, and in a ratio of from 0.75 to 1.25 phenolic hydroxyl equivalents per each 1,2-epoxide group in the epoxy coreactant, with (B) a dianhydride selected from the group consisting of benzophenone-3,3',4,4'-tetracarboxylic acid dianhydride and pyromellitic acid dianhydride, said reaction product (A) and the dianhydride (B) being reacted at a temperature of 80°-150° C. in an inert solvent and with a tertiary amine esterification catalyst, and in a ratio of 0.7 to 1.2 carboxylic acid anhydride equivalents of the anhydride for each hydroxyl group of product (A).