PROCESS FOR THE PRODUCTION OF A FOAMED THERMOPLASTIC RESIN SHEET

摘要

Process for continuously producing a foam sheet by heating a continuous sheet of a soft thermoplastic synthetic resin, said sheet prepared by a calendering process, which contains a chemical foaming agent at a temperature lower than the decomposition temperature of said chemical foaming agent eliminating the internal stress of said sheet elongating a corrugation formed on the sheet during said heating in the direction of the width thereof, and then heating at a temperature higher than the decomposition temperature of said chemical foaming agent to foam said sheet.