| 摘要 |
PURPOSE:To improve the flame retardancy, impact strength and arc resistance of the title composition by polymerizing a specific mixture of styrene monomers containing a nucleus-substituted monobromostyrene and a rubber, under conditions to obtain the soft component as dispersed particles having specific particle size and swelling index. CONSTITUTION:A composition composed of 80-99wt% of a mixture of styrene monomers containing 10-60wt% of a nucleus-substituted monobromostyrene, and 1-20wt% of a rubber, is molten by heating. The composition is subjected to the bulk polymerization with stirring, until the polymerization rate reaches 10-30%, when the rubber is dispersed as particles by the action of stirring. The composition is then polymerized to a polymerization rate of nearly 100% by the aqueous suspension polymerization in the presence of a suspension agent such as tribasic calcium phosphate, etc. The amount of the rubber and the polymerization conditions are selected to give the dispersed particles of soft component having an average particle size of 1.0-7.0mu, and a swelling index in toluene of 8.0-16.0. |
