Primer layer for plating process, laminate for circuit board and production method for same, and multilayer circuit board and production method for same

A primer layer for plating process formed of a resin composition for primer layer comprising (A) a polyfunctional epoxy resin, (B) an epoxy resin curing agent, and (C) a phenolic hydroxyl group-containing polybutadiene-modified polyamide resin having structural units represented by the following formulae (i), (ii) and (iii), wherein a blending proportion of the phenolic hydroxyl group-containing polybutadiene-modified polyamide resin (C) in the resin composition for primer layer is 5 parts by mass or more and less than 25 parts by mass based on 100 parts by mass of a total sum of the polyfunctional epoxy resin (A) and the epoxy resin curing agent (B):

• wherein
• each of a, b, c, x, y, and z represents an average degree of polymerization;
• a represents an integer of from 2 to 10;
• b represents an integer of from 0 to 3;
• c represents an integer of from 3 to 30;
• when x is 1, then (y+z) represents an integer of from 2 to 300;
• when y is 1, then z is 20 or more;
• each of R, R′, and R″ independently represents a divalent group derived from an aromatic diamine or an aliphatic diamine;
• and each R′″ independently represents a divalent group derived from an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, or an oligomer having a carboxyl group at both ends thereof.