SYNTHETIC RESIN COMPOSITION CONTAINING LEAD FLAKE

PURPOSE:To provide the titled compsn. having excellent soundproofing and X-ray-shielding effects, by arranging a large quantity of lead flake having an active metallic surface and little oxide layer thereon uniformly in the form of multi-lamination within a thermoplastic or thermosetting resin. CONSTITUTION:Lead having uniformity in weight is crushed along the slip plane of face-centered cubic structure in the presence of a material serving as a crushing aid as well as antioxidant (e.g., stearic acid or liquid paraffin) by using a pressure rolling machine to produce lead flake having an active metallic surface and no oxide layer thereon. The lead flake and a thermoplastic synthetic resin (e.g., a polyethylene resin) or a thermosetting resin (e.g., an epoxy resin) are repeatedly passed through a kneading roll to thereby mix them, thus obtaining the desired synthetic resin compsn. contg. about 5-65vol% lead flake having no oxide layer thereon in the form of multi-lamination arranged therein.