Patent ID: 6800227
Filing Date: 2004-10-05
Classification: B29C

Abstract:
A method for die-expanded molded foaming of synthetic resin comprising the steps of:filling material beads in a cavity enclosed within a pair of dies with chambers disposed on the rear sides respectively; heating, expanding and fusing the material beads to be a molded foam body; and cooling, releasing and taking out the molded foam body from the dies, wherein the following processes are included: a) a die closing process where the dies are closed to form said cavity air tightly isolated from said chambers, and to form utility passages independent from the chambers and directly connected to the cavity; b) a filling process where the material beads are supplied and filled into the cavity from a material tank while maintaining the pressure in the cavity at a predetermined pressure lower than the pressure in said material tank, at the same time heating steam is supplied to said chambers so as to heat the entire dies around the chambers to a temperature where the material beads do not expand; c) an internal heating process where heating steam having a temperature less than the fusing temperature of the material beads is supplied to said cavity through said utility passages so as to heat the filled material beads, and at the same time, form condensed water on the faces of the dies enclosing the cavity; and d) a fusion heating process where heating steam having a temperature at the fusion temperature of the material beads or higher is supplied to said chamber, so as to evaporate the condensed water in said cavity and to progress expansion and fusion of the material beads.