Photo-imaging resist ink and cured product thereof

A photo-imaging resist ink containing (A) an unsaturated group-containing polycarboxylic acid resin which is a reaction product of (c) succinic anhydride with an additive reaction product of (a) an epoxy resin with (b) an unsaturated group-containing monocarboxylic acid, wherein (a) said epoxy resin is represented by the following formula (1):

• ##STR7## wherein M stands for ##STR8## n is at least 1 on the average;
• and m is 1 to n on the average, wherein (A) said unsaturated group containing polycarboxylic acid resin is prepared by reacting (a) said epoxy resin with 0.8 to 1.3 mol, per equivalent of the epoxy groups of said epoxy resin, of (b) said unsaturated group containing monocarboxylic acid to form the said additive reaction product, and subsequently reacting said additive reaction product with 0.1 to 0.9 equivalent, per equivalent of the hydroxyl groups of said additive reaction product, of .COPYRGT. succinic anhydride.