| 摘要 |
PURPOSE:To produce the titled particles having excellent moldability in a mold, by foaming a base resin composed of an ethylene-propylene random copolymer and an alpha-olefin-propylene random copolymer having a heat of crystallization within a specific range. CONSTITUTION:The particles of a base resin composed of (A) 10-95wt% alpha- olefin-propylene random copolymer having a heat of crystallization of <=10cal/g by differential scanning calorimetry and (B) 90-5wt% ethylene-propylene random copolymer, are compounded with water, a volatile foaming agent and an dispersing agent. The mixture is heated in a closed vessel at Tm-25 deg.C-Tm-5 deg.C(Tm is the melt-completion temperature of the resin particle), and one end of the vessel is opened to release the resin particles and water to a low-pressure atmosphere to effect the foaming of the particles. The prefoamed particle produced by this process has a crystalline structure exhibiting a high-temperature peak at the temperature higher than the intrinsic peak of the base resin in a DSC curve (obtained by heating 1-3mg of the foamed particle to 220 deg.C at a rate of 10 deg.C/min by a differential scanning calorimeter), and the peak temperature difference between the intrinsic peak and the high-temperature peak of >=5 deg.C.
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