Foam from a vinyl chloride polymer, butadiene-acrylonitrile rubber and a plasticizer

Claim 1

A COMPOSITION OF MATTER HAVING UNUSUAL SHOCK ABSORBING CHARACTERISTICS COMPRISING A VULCANIZED UNICELLULAR MIXTURE OF A VINYL RESIN SELECTED FROM THE GROUP CONSISTING OF POLYVINYL CHLORIDE AND COPOLYMERS OF A MAJOR PROPORTION OF VINYL CHLORIDE AND A MINOR PROPORTION OF A COPOLYMERIZABLE MONOMER SELECTED FROM THE GROUP CONSISTING OF VINYL ACETATE, DIETHYL MALEATE, DIETHYL FUMARATE AND VINYLIDENE CHLORIDE, A BUTADIENE-ACRYLONITRILE RUBBERY COPOLYMER CONTAINING FROM 15 TO 40% OF COMBINED ACRYLONITRILE, AND A HIGH-BOILING ORGANIC LIQUID PLASTICIZER FOR SAID RESIN, SAID PLASTICIZER BEING COMPATIBLE WITH SAID RUBBERY COPOLYMER AND BEING SELECTED FROM THE GROUP CONSISTING OF ESTERS, ETHERS AND KETONES, THE AFOREMENTIONED COMPONENTS BEING EMPLOYED IN RELATIVE PROPORTIONS OF FROM 42 TO 66% OF SAID RESIN, FROM 20 TO 38% OF SAID RUBBERY COPOLYMER, AND FROM 14% TO A VALUE SUBSTANTIALLY BELOW 20% OF SAID PLASTICIZER, SAID PERCENTAGES BEING BASED ON THE SUM OF SAID CONSTITUENTS AND TOTALLING 100% SAID MIXTURE HAVING A DENSITY OF NOT OVER 10 POUNDS PER CUBIC FOOT AND A COMPRESSIVE RESISTANCE AT 25% COMPRESSION OF FROM 4 TO 10 POUNDS PER SQUARE INCH.