| 摘要 |
PURPOSE:To produce the subject product giving a good foamed molding when once stored as a non-foamed sheet and subsequently thermally foamed, by allowing a resin to contain a specific gas as a foaming agent and subsequently extruding the resin into a sheet-like product. CONSTITUTION:A polyamide, thermoplastic polyester or polycarbonate resin is fed into a tandem extruder comprising plural extruders connected to each other in series. In the first extruder the resin is melt-kneaded with a pressure of <=200kg/cm<2>, and a gas having a gas permeation degree of <=10CC.mm/ cm<2>.sec.cmHgX10<10> at 25 deg.C and in a relative humidity of 50% is simultaneously press-charged into the resin in an amount of 0.01-3 pts.wt. per 100 pts.wt. of the resin. The mixture is extruded from the first extruder into a sheet-like product with a pressure higher than the inner pressure of the first extruder and lower than 100kg/cm<2>. The extruded sheet is quenched in <=50 deg.C water to provide the objective non-foamed product having a thickness of 0.02-3mm and retaining the non-foamed state. |
