Rigid polyvinyl chloride resin compositions having increased resistance to heat deterioration

Claim 1

A RIGID POLYVINYL CHLORIDE RESIN COMPOSITION CONTAINING LESS THAN ABOUT 10% BY WEIGHT OF A PLASTICIZER, AND HAVING INCREASED RESISTANCE TO DETERIORATION WHEN HEATED AT 375*F. CONSISTING ESSENTIALLY OF (A) A RIGID POLYVINYL CHLORIDE POLYMER RESIN, (B) AN AMOUNT WITHIN THE RANGE FROM ABOUT 0.2 TO ABOUT 10 PARTS BY WEIGHT PER 100 PARTS OF POLYVINYL CHLORIDE RESIN OF AN ORGANOTIN COMPOUND IN WHICH TIN IS IN A TETRAVALENT STATE HAVING ORGANIC RADICALS LINKED TO TIN ONLY THROUGH CARBON AND OXYGEN, AT LEAST TWO ORGANIC RADICALS BEING LINKED THROUGH CARBON, AND AT LEAST ONE ORGANIC RADICAL BEING LINKED THROUGH OXYGEN TO A CARBOXYL GROUP OF AN UNSATURATED ALIPHATIC DICARBOXYLIC ACID ESTER OF AN ALCOHOL HAVING FROM ONE TO TWO HYDROXYL GROUPS, AND (C) AN AMOUNT WITHIN THE RANGE FROM ABOUT 0.01 TO ABOUT 2 PARTS BY WEIGHT PER 100 PARTS OF POLYVINYL CHLORIDE RESIN OF A HINDERED PHENOL HAVING AN INERT SUBSTITUENT IN EACH POSITION ORTHO TO EACH PHENOLIC HYDROXYL GROUP, TO ENHANCE THE STABILIZING EFFECT TO THE ORGANOTIN COMPOUND.