| 摘要 |
PURPOSE:To obtain a foamed molded article capable of omitting expansion process in molding in a mold and gradual cooling process, having improved heat-resistant creep, mechanical properties, surface gloss, and high quality, by using foamable particles having a specific particle structure. CONSTITUTION:A high-quality foamed molded article is obtained by using globular foamable particles having the surface with a smoothness degrees <=1.05, a magnification of expansion D about 20-40min times, a damping factor T of air pressure introduced in the particles by pressure in a range shown by the formula (1/1500-1/ 2500)D, namely expansion ability >=1.3 times, and improved gloss by molding in a mold without troublesome process control and condition control. Previously expanded particles are obtained by impregnating crosslinkable polyethylene resin particles with a blowing agent and putting the particles in such an atmosphere that the blowing agent existing in the surface layer of the particles vaporizes away and raising the temperature gradually in such a way that excess stress is not produced on the surface layer parts of the particles when the expanded particles with low magnificiation of expansion are processed into foamed particles with high magnification of expansion. |
