Post-chlorinated vinyl chloride polymer containing butadiene-acrylonitrile rubber and styrene-acrylonitrile copolymer

Claim 1

A COMPOSITION COMPRISING AN INTIMATE MIXTURE OF (A) 100 PARTS BY WEIGHT OF POST-CHLORINATED POLYVINYL CHLORIDE RESIN CHARACTERIZED BY HAVING A DENSITY OF FROM ABOUT 1.53 TO 1.59 GRAMS PER CC. AT 25*C. AND A CHLORINE CONTENT OF FROM ABOUT 64 TO 68% BY WEIGHT, A HEAT DISTRORTION TEMPERATURE, ACCORDING TO ASTM TEST METHOD D648-65, WITHIN THE RANGE OF 95*C. TO 125*C., AND HIGH HEAT STABILITY SUCH THAT IT IS NOT DEGRADED IF EXPOSED TO AIR AT 375 TO 400*F. FOR AT LEAST 10 MINUTES; AND (B) FROM 1 TO 15 PARTS BY WEIGHT OF A RESINOUS COPOLYMER OF STYRENE AND ACRYLONITRILE CONTAINING FROM 20 TO 35% BY WEIGHT OF POLYMERIZED ACRYLONITRILE UNITS AND HAVING A DILUTE SOLUTION VISCOSITY, MEASURED IN METHYL ETHYL KETONE SOLVENT AT 25*C., OF FROM 0.3 TO 0.7; AND (C) FROM 3 TO 15 PARTS BY WEIGHT OF A CROSS-LINKED RUBBERY COPOLYMER OF BUTADIENE AND ACRYLONITRILE CONTAINING FROM 20 TO 30% BY WEIGHT OF POLYMERIZED ACRYLONITRILE UNITS, CONTAINING AT LEAST 50% BY WEIGHT OF GEL THE MIXTURE CHARACTERIZED IN THAT IT IS EXTRUDABLE INTO PIPE SUITABLE FOR CONVEYING WATER AT A TEMPERATURE WITHIN THE RANGE OF AT LEAST 85* C. TO ABOUT 100*C.