Polypropylene resin pre-expanded particles having a weight of 0.3 to 1.8 mg per particle and a mean cell diameter of at most 250 µm and exhibiting two fusion peaks on a DSC curve thereof one of which appearing on a higher temperature side has a specific heat of fusion QH, which can be molded in a mold in a shortened molding time to give cellular molded articles having a low density of 25 g/liter or less after being provided with an inorganic gas pressure of at least 1.5 atms when the heat of fusion QH is 2.8 to 6.0 cal/g, or after being provided with an inorganic gas pressure of 1.18 to 1.5 atms when the heat of fusion QH is from 0.3 to less than 2.8 cal/g.
聚
丙烯树脂预膨化颗粒,每粒重量为 0.3 至 1.8 毫克,平均胞直径至多为 250 微米,在
DSC 曲线上显示两个熔融峰,其中一个熔融峰出现在温度较高的一侧,具有熔融比热 QH,在无机气体压力至少为 1.8 至 6.0 卡/克时,熔融比热 QH 为 2.8 至 6.0 卡/克;或在无机气体压力为 1.18 至 1.5 阿特姆时,熔融比热 QH 为 1.18 至 1.5 阿特姆。当熔融热 QH 为 2.8 至 6.0 卡/克时,在提供 1.18 至 1.5 阿特姆的无机气体压力后,或当熔融热 QH 为 0.3 至低于 2.8 卡/克时,在提供 1.18 至 1.5 阿特姆的无机气体压力后,可得到密度为 25 克/升或更低的蜂窝状模塑物。