| 摘要 |
929,302. Tyre treads. DUNLOP RUBBER CO. Ltd. Aug. 12, 1960 [Aug. 13, 1959], No. 27683/59. Class 144 (2). A vehicle-type tread comprises a vulcanized copolymer of at least 30% by weight of a conjugated diene, such as butadiene or isoprene, with a mono-ene, which vulcanized copolymer has a second order transition temperature of above - 35‹ C., and is not blended with another polymer, or copolymer having a second order transition temperature differing from its own by more than 15‹ C. The monoene component is preferably styrene but may also be methyl, ethyl, isopropyl, t-butyl, cyano, haloalkyl, 2-chloromethyl, methylα- chloro or 2-cyanoethyl acrylate, acrylonitrile, methacrylonitrile, a lower N-alkyl or N,N- dialkyl acrylamide or methacrylamide, vinyl pyridine cr methyl vinyl pyridine, an alkyl isopropenyl ketone or an alkyl vinyl ketone. For a butadiene-styrene copolymer the styrene content is in the range 35 to 60% by weight, and for a butadiene-methyl isopropenyl ketone the ketone is used in the proportion 35 to 50% by weight. The copolymers are compounded with the usual extender oils, vulcanizing agents, antioxidants and fillers and are said to provide better road grip at normal working temperatures compared with natural or GR-S rubbers as shown in Fig. 4. |
