Patent ID: 8071217

Claim:
A heat-curing epoxy resin composition comprising: (A) at least one epoxy resin having an average of more than one epoxide group per molecule; (B) at least one hardener for epoxy resins which is activated by elevated temperature; at least one end-capped polyurethane prepolymer of formula (I) where the at least one end-capped polyurethane prepolymer of formula (I) is the reaction product of: a linear or branched polyurethane prepolymer PU1 terminated with p isocyanate groups and one or more isocyanate-reactive compounds R 2 H; R 1 is the structural portion of the polyurethane prepolymer PU1, excluding the isocyanate groups; p is a value from 2 to 8; each R 2 is independently selected from the group consisting of and â€”Oâ€”R 18 ; where each R 5 , R 6 , R 7 and R 8 is independently selected from the group consisting of an alkyl group, a cycloalkyl group, an aralkyl group, and an arylalkyl group; and alternatively, R 5 together with R 6 or R 7 together with R 8 form a portion of a 4- to 7-membered ring which is optionally substituted; each R 9 , R 9 â€², and R 10 is independently selected from the group consisting of an alkyl group, an aralkyl group, an arylalkyl group, an alkoxy group, an aryloxy group, and an aralkyloxy group; R 11 is an alkyl group; each R 13 and R 14 is independently selected from the group consisting of an alkylene group having from 2 to 5 carbon atoms and optional double bonds or substitution, a phenylene group, and a hydrogenated phenylene group; each R 15 , R 16 , and R 17 is independently selected from the group consisting of a hydrogen atom, an alkyl group, an aryl group, and an aralkyl group; and R 18 is selected from the group consisting of an aralkyl group, a substituted aromatic group, and an unsubstituted aromatic group, wherein the aromatic groups optionally feature hydroxy groups; and at least one polyurethane prepolymer terminated by epoxide groups of formula (II) where the at least one polyurethane prepolymer terminated by epoxide groups of formula (II) is the reaction product of: a linear or branched polyurethane prepolymer PU1â€² terminated with n isocyanate groups and a monohydroxyl epoxide compound having m epoxy groups and a single primary or secondary hydroxyl group; m is 1, 2 or 3; n is a value from 2 to 8; R 3 is the structural portion of the polyurethane prepolymer PU1â€², excluding the isocyanate groups; and R 4 is the structural portion of the monohydroxyl epoxy compound, excluding the epoxy groups and the primary or secondary hydroxyl group, wherein R 4 is structurally aliphatic, cycloaliphatic, aromatic or araliphatic.