| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cross-linked foamed product capable of being easily improved in surface wettability by a corona discharge treatment, capable of being well formed by a vacuum or stumping molding treatments and useful for automotive heat-insulating cushion materials by compounding a resin component comprising a polypropylene-based resin and a specific olefinic resin. SOLUTION: This cross-linked foamed product of polypropylene-based resin contains (Z) a resin component comprising (A) 75-95 wt.% or a polypropylene-based resin (for example, the resin having a melt index of 0.4-8 g/10 min under a load of 2.16 kgf at 230 deg.C) and (B) 5-25 wt.% of a low crystalline polyα-olefinic resin (for example, propylene-ethylene/butene-1 copolymer) having a mol.wt. of 3,000-50,000 and a crystallinity of 5-15%. The foamed product is obtained, for example, by melting and kneading the component Z, (X) a thermal decomposition type foaming agent, a cross- linking accelerator and, if necessary, one or more additives in a kneading machine at a temperature below (Tx) the decomposition temperature of the component X, forming the kneaded product into a foamed resin sheet, irradiating the sheet with ionizing radiations to cross link the sheet, and subsequently heating the cross-linked sheet at the decomposition temperature Tx of the component X or higher to foam the resin foamed sheet.
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