Method of producing cellular resin bodies

Claim 1

A PROCESS OF PRODUCING A CLOSED-CELL CELLULAR THERMOPLASTIC RESIN ARTICLE HAVING WINKLED CELL WALLS, COMPRISING THE STEPS OF FORMING A GAS-EXPANDED CELLULAR THERMOPLASTIC RESIN BODY HAVING CLOSED GAS-PERMEABLE CELLS CONTAINING GAS AT A PRESSURE AT LEAST EQUAL TO ATMOSPHERIC PRESSURE; SUBJECTING SAID CELLULAR THERMOPLASTIC RESIN BODY AT AT LEAST ATMOSPHERIC PRESSURE AT A RAISED TEMPERATURE BELOW THE TEMPERATURE AT WHICH SAID THEMOPLASTIC RESIN BODY STARTS TO FLOW TO AN ATMOSPHERE CONSISTING AT LEAST PARTLY OF VAPOR WHICH IS LIQUID AT ROOM TEMPERATURE AND VAPOR AT SAID RAISED TEMPERATURE SO AS TO CAUSE SAID VAPOR AND THE GAS IN SAID CELLS TO DIFFUSE THROUGH THE GASPERMEABLE CELL WALLS SO THAT SAID VPOR AT LEAST PARTIALLY REPLACES THE GAS IN SAID CLOSED CELLS WITHOUT EXPANSION OF SAID CELLS, THEREBY FORMING A CLOSED-CELL CELLULAR THERMOPLASTIC RESIN BODY CONTAINING IN SAID CLOSED CELLS SAID VAPOR AND HAVING A GAS PRESSURE INCLUDING THE PRESSURE DUE TO SAID VAPOR AT LEAST EQUAL TO ATMOSPHERIC PRESSURE; AND COOLING THE THUS FORMED CELLULAR THERMOPLASTIC RESIN BODY CONTAINING VAPOR IN THE CLOSED CELLS THEREOF SO AS TO CAUSE SAID VAPOR TO CONDENSE, THEREBY REDUCING THE PRESSURE IN SAID CLOSED CELLS CAUSING SAID CLOSED CELLS TO PARTIALLY COLLAPSE AND THE CELL WALLS TO BECOME WRINKLED.