Preparation of expandable ethylenically unsaturated polymer particles and cellular product therefrom

Claim 1

A PROCESS FOR THE PRODUCTION OF SHAPED CELLULAR POLYMERIC STRUCTURES COMPRISING FORMING AN AQUEOUS SUSPENSION OF PARTICLES OF A POLYMER OBTAINED BY POLYMERIZING AN ETHYLENICALLY UNSATURATED HYDROCARBON MONOMER, SAID SUSPENSION BEING STABILIZED BY AN INORGANIC DIFFICULTLY WATER-SOLUBLE DISPERSING AGENT, ADDING THERETO A NORMALLY LIQUID ALIPHATIC HYDROCARBON HAVING A BOILING POINT BELOW THE INCIPIENT SOFTENING POINT OF SAID POLYMER, MAINTAINING SAID ALIPHATIC HYDROCARBON IN CONTACT WITH SAID SUSPENSION UNTIL SAID HYDROCARBON IS INTEGRATED WITH SAID POLYMER PARTICLES, SEPARATING SAID PARTICLES FROM SAID AQUEOUS SUSPENSION, FILLING A MOLD WITH SAID POLYMER PARTICLES, HEATING SAID POLYMER PARTICLES TO AT LEAST THE INCIPIENT SOFTENING POINT OF THE POLYMER WHEREBY THE DISCRETE POLYMER PARTICLES COALESEE TO PRODUCE AN INTEGRAL CELLULAR POLYMERIC STRUCTURE AND REMOVING SAID STRUCTURE FROM SAID MOLD.