1452080 Polybutadiene coated unvulcanised rubber JAPAN SYNTHETIC RUBBER CO Ltd 31 Dec 1973 [30 Dec 1972] 60286/73 Heading B2E Pellets have a core of unvulcanised rubber and a coating of a 1, 2-polybutadiene, the 1, 2-polybutadiene containing at least 70% 1, 2 addition units and having a crystallinity not less than 10% and an intrinsic viscosity (measured in toluene at 30‹C) of not less than 0.7 al/g. The unvulcanised rubber may be natural rubber, a styrene butadiene rubber, an acrylonitrile-butadiene rubber a polybutadiene rubber, a polyisoprene rubber, a polychloroprene rubber, a butyl rubber, or an ethylenepropylene-diene terpolymer rubber, or a blend of two or more thereof. One or more compounding ingredients may be blended with the 1, 2-polybutadiene and/or the unvulcanised rubber and these include reinforcing agents, fillers, extender oils, pigments, vulcanising agents, vulcanisation accelerators, vulcanising activators, antioxidants, perfumes and softeners. A process for the production of these pellets comprises forming pellets of unvulcanised rubber and coating the rubber with 1, 2-polybutadiene whose physical properties are as described above.
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