| 摘要 |
Moulding compositions are made by dissolving 1 to 20 parts of a solid copolymer of 95 to 99 per cent of isobutylene and 5 to 1 per cent of isoprene in 100 parts of styrene, and then polymerizing the styrene. The polymerization may be effected in the presence of 0.01 to 0.1 parts of a catalyst, such as benzoyl peroxide, lauroyl peroxide, di-tertiary butyl peroxide, di-tertiary butyl perphthalate, tertiary butyl percaprylate or tertiary butyl perbenzoate in bulk or in aqueous suspension in the presence of a suspending agent, e.g. tricalcium phosphate, calcium carbonate or aluminium hydroxide, at temperatures from 50 DEG to 200 DEG C. Plasticizers, stabilizers, destaticizing agents, pigments, dyes and fillers may be added. In the example, a copolymer of 98 per cent of isobutylene and 2 per cent of isoprene, stearic acid and di-tertiary butyl peroxide is dissolved in styrene and the solution heated for 20 hours at 95 DEG C. and 24 hours at 120 DEG C. The product is comminuted and injection moulded to form articles having a pearlescent surface.
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