Patent ID: 7517934

Claim:
An oligomer-modified anionically polymerized polymer comprising the reaction product of: (a) a free-radically polymerized oligomer consisting of the reaction product of one or more monomers selected from the group consisting of vinyl aromatic monomers and ester functional monomers and one or more monomers selected from the group consisting of epoxy functional monomers, anhydride functional monomers, ester functional monomers and carboxylic acid functional monomers, the oligomer having a number average molecular weight of about 1000 to about 5000 g/mol and a weight average molecular weight of about 1500 to about 18,000 g/mol; a number average number of functional groups from about 4 to about 12; and a polydispersity index of about 1.5 to about 4.5 and (b) an anionically polymerized polymer; wherein the number average number of functional groups is calculated based upon functional groups selected from the group consisting of epoxy functional groups, anhydride functional groups, and carboxylic acid functional groups.