PRODUCTION OF FOAMING THERMOPLASTIC POLYMER GRAIN

摘要

PURPOSE:To obtain the title polymer grain having uniform grain size in good yield by polymerizing a polymerizable monomer with thermoplastic polymer grains and then impregnating a foaming agent into the polymerized product. CONSTITUTION:(A) An aqueous dispersing medium containing (i) 0.1-1.0 pts. slightly water-soluble inorganic salt, (ii) 60-180ppm anionic surfactant and (iii) 20-200ppm nonionic surfactant and/or 20-150ppm polyvinyl alcohol in 100 pts.wt. water is used and (C) a polymerizable monomer is continuously or continually added to (B) a thermoplastic polymer grains suspended in the above-mentioned aqueous dispersing medium and having uniform grain size and the mixture is polymerized and then (D) readily volatile foaming agent is impregnated into the polymerized product to provide the aimed polymer grains.