The Influence of the Distribution State of Flame-retardants and Talc on the Flammability of Polypropylene

Flammability of polymer is a phenomenon of oxidation reaction at near surface of products. Distribution of filler and flame-retardant at surface of products is thought to influence the flammability. So model samples that have various distributions of flame-retardant and filler, were made by using high-speed sandwich injection moldings. In this study, two types of flame-retardant, bromine type and phosphorous type, were used. The model sample which had high flame-retardant content in surface layer and high filler content in core layer, had good flammability and mechanical properties. Especially, phosphorous flame-retardant showed superior effect in that small amount of flame-retardant achieved same flammability as flame-retardant PP without filler. Control of distribution of flame-retardant and filler by using high-speed sandwich injection molding is cost-effective method with low flame-retardant addition.