Blends of polystyrene and a graft copolymer of a styrene-methyl methacrylate type mixture on a rubbery polymer of a conjugated 1, 3-diene

Claim 1

AN INTIMATE PHYSICAL ADMIXTURE OF POLYMERIC COMPONENTS CONSISTING OF (A) POLYSTYRENE AND (B) A GRAFT COPOLYMER PREPARED BY POLYMERIZING ABOUT 25-100 PARTS BY WEIGHT OF A MONOMER MIXTURE CONSISTING ESSENTIALLY OF 20-80% BY WEIGHT OF STYRENE AND, CORRESPONDINGLY, 80-20% BY WEIGHT OF METHYL METHACRYLATE IN AN AQUEOUS DISPERSION OF 100 PARTS BY WEIGHT OF RUBBER POLYMER HAVING A SECOND ORDER TRANSITION TEMPERATURE NOT HIGHER THAN ABOUT 0* CENTIGRADE, AS DETERMINED BY ASTM TEST D746-52T, SELECTED FROM THE GROUP CONSISTING OF POLYBUTADIENE, POLYISOPRENE, INTERPOLYMERS OF 50-95 WEIGHT PERCENT OF BUTADIENE AND 50-5 WEIGHT PERCENT OF STYRENE AND INTERPOLYMERS OF 50-95 WEIGHT PERCENT OF ISOPRENE AND 50-5 WEIGHT PERCENT OF STYRENE; SAID POLYSTYRENE AND GRAFT COPOLYMER BEING COMBINED IN SUCH PROPORTIONS THAT THE GRAFT COPOLYMER SUBSTRATE CONSTITUTES 5-40% BY WEIGHT OF THE ADMIXTURE.