Epoxy resin/phenolic OH-aramid/ban block copolymer product with CTBN

An epoxy resin composition comprising:

• (A) an epoxy resin modified material obtained by reacting an epoxy resin and a phenolic hydroxyl group-containing aramid/polybutadiene-acrylonitrile block copolymer represented by formula (I):
• ##STR7## wherein Ar.sup.1 and Ar.sup.2 each represent a divalent aromatic group;
• Ar.sup.2 represents a phenolic hydroxyl group-containing divalent aromatic group;
• x represents an integer of from 3 to 7;
• y represents an integer of from 1 to 4;
• y/(x+y) is from 0.1 to 0.3;
• z represents an integer of from 5 to 15;
• m represents an integer of from 1 to 400;
• n represents an integer of from 1 to 400;
• n/(m+n) is from 0.01 to 0.50;
• and l represents an integer of from 1 to 50,
• (B) an epoxy resin,
• (C) a hardener other than the polybutadiene-acrylonitrile copolymer having a carboxyl group at both terminals thereof and
• (D) a polybutadiene-acrylonitrile copolymer having a carboxyl group at both terminals thereof.