초록 ▼

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 .mu.m 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

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 .mu.m 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.

대표청구항 ▼

1. A pre-expanded particle of a polypropylene resin having a weight of 0.3 to 1.25 mg per particle, an average cell diameter of 250 .mu.m or less and a bulk density of 10 to 20 g/liter, wherein said pre-expanded particle shows two fusion peaks on a differential scanning calorimetry (DSC) curve when

1. A pre-expanded particle of a polypropylene resin having a weight of 0.3 to 1.25 mg per particle, an average cell diameter of 250 .mu.m or less and a bulk density of 10 to 20 g/liter, wherein said pre-expanded particle shows two fusion peaks on a differential scanning calorimetry (DSC) curve when measured by differential scanning calorimetry, and the heat of fusion QH of the peak appearing on a higher temperature side is from 2.8 to 6.0 cal/g.