Patent ID: 8093322

Claim:
A curable composition comprising: an oligomer; at least one monomer; and an amount of a substantially non-reactive oligomeric additive that is effective to yield a cured product having a fracture toughness value that is higher than the fracture toughness value of a cured product of an otherwise identical composition lacking the non-reactive oligomeric additive, wherein the substantially non-reactive oligomeric additive has a structure or average structure according to formulae (I), (II), or (III) CAP 1 —RT′—OOC—NH—R 1 —NH—COO—RT′—CAP 1 (I) R M —[OOC—NH—R A —NH—COO—RT′—CAP 1 ] n (II) CAP 1 —RT′—OOC—NH—R 1 —NH—[COO—R 2 —OOC—NH—R 1 —NH] w —COO—RT′—CAP 1 (III) wherein RT′—CAP 1 is the reaction product of a moiety (RT) having a reactive terminus and a capping moiety comprising a functional group that reacts with the reactive terminus, wherein RT′—CAP 1 has a non-reactive terminus, R 1 is a polyisocyanate core moiety substantially free of urethane bonds, R A is R 1 or —R 1 —(NH—COO—R C —OOC—NH—R 1 ) t — where R C is a polyol-containing core moiety and t has an average value in the range of 0 to about 4, R M is a core moiety having an average functionality of n, where n is greater than 2.2, R 2 includes either at least one crystallizable polyol-derived moiety or at least one cyclic rigid moiety, and w is greater than zero.