METHOD OF IN-MOLD FOAM MOLDING FOR POLYOLEFIN BASED RESIN FOAMED ARTICLE

摘要

A method of in-mold foam molding for a polyolefin-based resin foamed article wherein a molding space is filled with pre-foamed particles being composed of a base resin of a polyolefin based resin and having a bulk density of 30 to 100 kg/m<3> and a DSC ratio of 5 to 35 % while being pressured with an inorganic gas, and the pre-foamed particles are heated and fused with steam, characterized in that the pre-foamed particles are subjected to a pressuring treatment under a pressure of 0.3 to 1.0 MPa with an inorganic gas before the above filling. The method allows the molding of pre-foamed particles having a high bulk density, which have been conventionally able to be molded only by the inner pressure imparting method having a disadvantage of high equipment cost, by the use of the compression filling molding method, which is advantageous over the former method in productivity and equipment cost, and further allows the production of a foamed article having a improved filling ratio and improved appearance.