Patent ID: 7638259

Claim:
A polyimide resin, characterized in that the polyimide resin comprises three kinds of repeating units represented by the formula (1), and has a weight average molecular weight, reduced to polystyrene, of from 5,000 to 500,000, an acryl equivalent of from 400 to 3,000 g/eq, and a carboxylic acid equivalent of from 300 to 2500 g/eq wherein X is a tetravalent organic group, Y is represented by the following formula (3) wherein A may be the same with or different from each other and is a divalent organic group selected from the following groups B and C may be the same with or different from each other and are C 1-4 alkyl groups, alkoxy groups or hydrogen atoms, a and b each are 0 and 1, and c is an integer of from 0 to 10, R 1 may be the same with or different from each other and is selected from the following groups at least one of R 1 is selected from the following group, wherein R 3 is represented by the following formula —R 4 (OR 3 ) 2 wherein R 4 is a C 3-6 trivalent hydrocarbon group, and R 3 may be different from each other and is selected from the group consisting of a hydrogen atom, a residue of C 6-14 (meth)acryloyloxy isocyanate induced through a reaction of an isocyanate group of the C 6-14 (meth)acryloyloxy isocyanate with an alcoholic hydroxyl group of —R 4 OH, and a residue of a C 4-14 acid anhydride induced through a reaction of an anhydride group of the C 4-14 acid anhydride with an alcoholic hydroxyl group of —R 4 OH, Z is a divalent organic group which does not have any of (meth)acryl, carboxyl, and hydroxyl groups, W is a divalent organic group having a polyorganosiloxane structure, and X, Y, Z and W each may be a mixture of two or more groups, k is a number of from 0.2 to 1.0, m is a number of from 0 to 0.8, and n is a number of from 0 to 0.8, with k+m+n being 1.