摘要 |
Expandable styrene polymer particles having reduced flammability are made by incorporating from 0.1 to 15 weight percent of non-polymeric organic halogen compounds into the polymer during impregnation of the polymer particles with a blowing agent in aqueous suspension. The addition of 0.001 to 0.5 weight percent of dialkyl tin maleates or fumarates during the impregnation step produces expandable styrene polymer particles with greatly improved molding characteristics such as reduced pruning tendency, increased mold fusion, and greater dimensional stability. Addition of a synergistic amount of 0.001 to 0.4 weight percent of a hindered phenolic antioxidant with the tin compounds gives improved molding characteristics with retention of polymer molecular weight. |