US Patent 8697811 Curable resin composition and cured resin

A curable resin composition, which contains, with respect to 100 parts of an epoxy resin, 1 to 70 parts of an epoxy resin curing agent and 1 to 50 parts of an acrylic block copolymer, and the acrylic block copolymer contains (α) at least one polymer block A composed of a structural unit derived from an alkyl methacrylate and at least one polymer block B composed of a structural unit derived from an alkyl acrylate, has a weight average molecular weight (Mw) of 30,000 to 300,000 and a molecular weight distribution (Mw/Mn) of 1.5 or less, and contains 3 to 60 percent by mass of the polymer block A. In addition, a cured resin is formed from the above curable resin composition.