Copolymerizable molding compositions based on unsaturated polyurethanes

Claim 1

A molding composition comprising: (a) 5 to 77% by weight of a polyurethane of the formula ##STR3## wherein R 1 is alkylene with 2 to 8 carbon atoms, cycloalkylene or arylene with 5 to 12 carbon atoms, a mixed aliphatic/cycloaliphatic or a mixed aliphatic/aromatic divalent group with 7 to 24 carbon atoms, each of these groups may also contain 1 to 3 oxygen atoms, or a divalent radical of a polyester which contains no α,β-ethylenic unsaturations, R 2 is alkylene with 2 to 8 carbon atoms, cycloalkylene or arylene with 6 to 12 carbon atoms or a mixed aliphatic/cycloaliphatic or a mixed aliphatic/aromatic divalent group with 7 to 24 carbon atoms, R 3 is ##STR4## X is H, CH 3 , COOH or COO--"alkylene"--OH, Y is hydrogen or methyl, "alkylene" is alkylene with 2 to 6 carbon atoms, and n is zero or a number from 1 to 15; (b) 20 to 80% by weight of a vinyl or vinylidene compound copolymerizable with (a); and (c) 3 to 25% by weight of a rubbery-elastic polymer; wherein the composition percentages are based on the sum of the weights of components (a), (b) and (c); and wherein said composition, upon curing, yields a two-phase system comprising a rubbery phase containing said rubbery-elastic polymer and having a glass transition temperature of between -90° and 10° C. and a resin phase having a glass transition temperature of between 50° and 250° C., the discontinuous phase having an average particle diameter of 0.1 to 100 μm; and wherein the specific fracture surface energy of the resulting copolymer phase of (a) and (b), without (c), being formed during hardening will be greater than 0.6×10 5 ergs per square centimeter.