Kaneka Corporation

Shinobu Ochikoshi

Naruhiko Akamatsu

Toru Yoshida

Kyoichi Nakamura

Yutaka Yanagihara

Hisatoshi Fukui

Kyosuke Murakami

Hideya Mizuike

A bulk-density measuring device includes a first vessel in which contracted pre-expanded particles are swollen and recovered from contraction in a pressure-reduced state where a vessel internal pressure is lower than atmospheric pressure; a second vessel filled with the pre-expanded particles after being swollen in the first vessel in the pressure-reduced state where a vessel internal pressure is lower than the atmospheric pressure, and into which the pre-expanded particles of a constant volume are collected fractionally; a pressure-reducing unit that adjusts the vessel internal pressures of the first vessel and the second vessel to be lower than the atmospheric pressure; and a scale that measures a weight of the pre-expanded particles filled in the second vessel.

Bulk-density measuring device for pre-expanded particles and method for manufacturing pre-expanded particles

Pre-expanded particles of polyolefin resin having less fluctuation in expansion ratio, uniform particle size and low expansion ratio are provided without using any volatile foaming agent. The low expansion ratio means 2 to 10 times, preferably 3 to 8 times. Resin particles to be released are uniformly contacted with saturated vapor at the time of pre-expanding polyolefin resin particles by dispersing the resin particles into an aqueous dispersion medium in a closed vessel, heating the resin particles to temperature of at least the softening point of the polyolefin resin and releasing the particles from the closed vessel into an atmosphere of lower pressure than the inner pressure of the closed vessel.

Process for preparing polyolefin pre-expanded particles

Method for post-treatment of polyolefin resin pre-expanded particles

Growing community of inventors

Osaka, Japan

Shinobu Ochikoshi