Patent ID: 8658723

Claim:
A heat-curable epoxy resin composition, comprising: a) a glycidyl epoxy resin; and b) an impact modifier that is selected from the group consisting of: a polyesteramide, a copolymer formed from a polyester and polyamide, a polyurethane, or a polyurethane formed from a polyester; wherein: i) the ester-containing portion of the impact modifier consists of: 1) a residue from a dimer fatty diol; or at least one acid residue selected from the group consisting of: a dimer fatty acid and a non-dimeric fatty acid; and 2) at least one diol residue selected from the group consisting of: a polyol having molecular weight of between 50 and 200 and a dimer fatty diol; provided that the ester-containing portion of the impact modifier contains a residue from at least one of the following: the dimer fatty acid, the dimer fatty diol, or both; ii) the composition phase separates upon curing to form phase-separated domains and/or particles comprising the impact modifier; and iii) the weight ratio of epoxy resin:impact modifier is in the range from 1.5 to 20:1.