Thermoformable, chemical resistant polymer blends

A thermoformable polymer blend that is resistant to the solvent effects of halogenated hydrocarbons comprising:

• A) from 50.1 to 59.9 parts by weight impact modified monovinylidene aromatic polymer, comprising from 1 to 25 weight percent of a rubber and 75 to 99 weight percent of a monovinylidene aromatic polymer matrix having weight average molecular weight (Mw) from 50,000 to 400,000, said weight percents being based on the total weight of said impact modified, monovinylidene aromatic polymer;
• B) from 30.1 to 39.9 parts by weight of an olefin polymer, selected from the group consisting of homopolymers of ethylene and copolymers of ethylene with one or more C4- 8 .alpha.-olefins;
• and
• C) from 5 to 25 parts by weight of a compatibilizing polymer, adapted to increase interfacial adhesion between components A) and B), components A) and B) existing in said blend as co-continuous phases, and the sum of A), B) and C) being 100 parts;
• said compatibilizing polymer being an elastomeric styrene/butadiene/styrene or styrene/isoprene/styrene triblock copolymer having weight average (Mw) and number average (Mn) molecular weights of from 10,000 to 150,000 and containing from 25 to 45 weight percent styrene.