THERMOFORMING OF FLEXIBLE PLASTIC FOAMY SHELLS

摘要

An improved method and apparatus for rapidly forming plastic foam shells from a flexible foam sheet. The foam sheet (10a) is intermittently passed through a radiaent heating unit and is rapidly heated on both sides to 130-250 DEG F to soften the foam. The heated foam sheet is immediately passed through a forming die unit in which the foam sheet is deformed partly into the die cavity (23) by withdrawal of air from the cavity, and a die plug (25) descends and final forms a shell while rapidly cooling the foam shell to below its plastic deformation temperature. By this forming method and apparatus, ethylene-containing foam shells having a depth 10-25 times the foam sheet initial thickness are rapidly formed at 10-30 cycles/minute.