| 摘要 |
1,142,298. Flame-retarded foamable polystyrene. MONSANTO CHEMICAL Ltd. 16 May, 1967 [15 June, 1966; 27 July, 1966], Nos. 26750/66 and 33790/66. Headings C3C and C3P. Particles of a foamable polystyrene have incorporated therein a volatile blowing agent and 0À1-1À5% by weight of the particles of pentabromophenyl allyl ether as flame retardant agent. They may be produced by polymerizing styrene in the presence of the volatile blowing agent and the flame retardant agent such that the product contains 0À1-1À5% by weight of the latter. Suitable blowing agents are a pentane or petroleum ether. Suspension polymerization may be used, a suitable catalyst being benzoyl peroxide. Suspending agents may be present, e.g. sodium pyrophosphate, sodium bicarbonate and polyvinylpyrrolidione. The resultant foamable polystyrene particles are foamed by application of heat to obtain a shaped, flame-retardant foamed product. The heating may be by steam, hot water, hot air or by use of an infra-red heater. |
