| 摘要 |
PROBLEM TO BE SOLVED: To provide a crosslinked polyolefinic resin foam having high heat resistance and flexibility, and to provide a manufacturing method therefor. SOLUTION: Crosslinked polyolefinic resin foam is obtained by crosslinking and foaming a polyolefinic resin containing 30 wt.% or more of a PP type resin and characterized in that a thickness is not more than 1 mm, the total crosslinking degree is not less than 65%, and the crosslinking degree of each of surface layer parts up to a depth of 500μm from both surfaces is higher than the crosslinking degree of an intermediate layer excepting the surface layer of both surfaces by 3% or more. This crosslinked polyolefinic resin foam, a polyolefinic resin containing 30 wt.% or more of the PP type resin, a thermally decomposable foaming agent and a crosslinking aid are melted and kneaded to be molded into a sheet. Both surfaces of this sheet is irradiated with ionizing radiation with an accelerated volt of 60-1,200 kV at a dose of 0.1-30 Mrad and, at the time of irradiations, both surfaces of the sheet is further irradiated with ionizing radiation with an accelerated voltage of 100-300 kV in a dose of 1-500 Mrad. This irradiated sheet is subsequently heated and foamed to produce the crosslinked polyolefinic resin foam. COPYRIGHT: (C)2004,JPO |
