| 摘要 |
PROBLEM TO BE SOLVED: To obtain a crosslinked polyolefin resin foam which can be free of discharge dielectric breakdown holes by crosslinking a polyolefin resin in a resin compsn. comprising the resin, a metal alkenylsulfonate, and a blowing agent with an electron beam and incorporating closed cells into the compsn. SOLUTION: The objective closed-celled foam having a degree of crosslinking of a polyolefin resin of 10-70% is obtd. by irradiating a resin compsn. comprising 100 pts.wt. polyolefin resin, 0.05-3 pts.wt. metal alkenylsulfonate, and a thermally decomposable blowing agent (e.g. azodicarbonamide) with an ionizing radiation. The polyolefin resin is a polyethylene resin having a density of 0.915-0.940 g/cm3 and an MFR of 1-30 g/10 min, a polypropylene resin having an m.p. of 125-155 deg.C and an MFR of 0.5-10 g/10 min, or a mixture thereof. An alkali or alkaline earth metal salt of a 9-13C alkenylsulfonic acid having an m.p. of 170-210 deg.C is used as the metal alkenylsulfonate.
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