POLYOLEFIN FORMING BEAD AND USE THEREOF

PROBLEM TO BE SOLVED: To obtain polyolefin foaming beads which can be processed in a wide processing range without being damaged by specifying the areal ratio between the low-temp. peak and the high-temp. peak in the initial heating and the heat of fusion of a secondary crystal. SOLUTION: A dispersion comprising plastic granules (which comprise a polyolefin consisting of homopolymers and copolymers of ethene, propene, and butene-1 and having a melt flow index (DIN ISO 1133, 230 deg.C) of 1-30 g/10 min, pref. 5-25 g/10 min, and a solid blowing agent) and a liq. dispersant, is charged together with a blowing agent into a pressure-resistant reactor, then subjected to heat treatment, and gushed out into a low-pressure chamber to be expanded. Thus, the expanded polyolefin beads of which the areal ratio of the low-temp. peak and the high-temp. peak of the DSC curve in the initial heating is at most 3 and the heat of fusion of the secondary crystal is 10 J/g or higher, are obtained.