Abstract: Multilayer, positive working, thermally imageable, bakeable imageable elements have a substrate, an underlayer, and a top layer. The underlayer comprises a polymeric material that comprises, in polymerized form from about 5 mol % to about 30 mol % of recurring units derived from an ethylenically unsaturated polymerizable monomer having a carboxy group; from about 20 mol % to about 75 mol % of recurring units derived from N-phenylmaleimide, N-cyclohexylmaleimide, N-benzylmaleimide, or a mixture thereof; and from about 3 mol % to about 50 mol % of recurring units derived from a compound represented by the formula: CH2?C(R2)—C(O)—NH—CH2—OR1, in which R1 is C1 to C12 alkyl, phenyl, C1 to C12 substituted phenyl, C1 to C12 aralkyl, or Si(CH3)3; and R2 is hydrogen or methyl. Other materials, such as a resin or resins having activated methylol and/or activated alkylated methylol groups, such as a resole resin, may be present in the underlayer.

Abstract: Photocurable compositions with, as photoinitiator, sulfonium salts of the formula: ##STR1## wherein Ar is a fused aromatic radical; R.sub.1 is a divalent organic bridge; each R.sub.2 and R.sub.3 individually is an alkyl, aryl, alkaryl, aralkyl or substituted aryl, provided that not more than one of R.sub.2 and R.sub.3 is alkyl; and A is a non-nucleophilic anion; use thereof and preparation thereof.

Abstract: Sulfonium salts of the formula: ##STR1## wherein Ar is a fused aromatic radical; R.sub.1 is a divalent organic bridge; each R.sub.2 and R.sub.3 individually is an alkyl, aryl, alkaryl, aralkyl or substituted aryl, provided thatn not more than one of R.sub.2 and R.sub.3 is alkyl; and A is a non-nucleophilic anion; use thereof and preparation thereof.