Patent ID: 6214896
Filing Date: 2001-04-10
Classification: C08J,C08L

Abstract:
A pre-expanded particle of a polypropylene resin prepared by pre-expanding a water-containing polypropylene resin composition comprising (A) 100 parts by weight of a polypropylene resin having melt flow rate (230.degree. C., 2.16 kg load) of 10 to 70 g/10min and tensile elongation at break of at least 300%, (B) 0.05 to 10 parts by weight of a hydrophilic polymer, and (C) 0 to 3 parts by weight of a filler and having a water content of 1 to 20% by weight under a water vapor pressure at the melting point of the polypropylene resin,said particle having an apparent expansion ratio of 25 to 70 times, a closed cell content of at least 85% and an average cell diameter of 50 to 500 .mu.m.