| 摘要 |
1401367 Coated elastomeric particles GOODYEAR TIRE & RUBBER CO 9 March 1973 [7 April 1972] 11503/73 Heading B2E Elastomeric particulate material of the powder, crumb or pellet type is coated to obtain a dry, non-conglomerating product by mixing and coagulating a slurry of the particulate material, a coagulant and a resin latex, the latex having a concentration of 0.1-8% by weight of resin, the coagulant being 0.01-10% by weight aqueous solution and the coating being carried out at a temperature between 5‹C under the agglomeration temperture and the lower of the melting or decomposition temperatures of such resin. The elastomers may be styrene-butadiene, acrylonitrile-butadiene, polybutadiene or polyisoprene rubber. The particulate material may include oil, carbon black, silica, clay and may comprise primarily such materials bonded together with the elestomer. The coating resin may be styrene-butadiene copolymer, styrene-butadienedivinyl benzene terpolymer, acrylonitrile-styrene-butadiene terpolymer, polyvinyl chloride, polystyrene and polymethyl methacrylate. Examples of suitable coagulants are aluminium sulphate, magnesium sulphate, calcium chloride, calcium oxide and barium hydroxide. The resin latex may be added to the aqueous solution of the coagulant in which the particles are slurried. Alternatively the particles may be slurried in the latex, and the coagulant solution added slowly. In a typical example a slurry of elastomeric crumbs is prepared by slowly pouring styrene-butadiene rubber latex (23% solids) into an agitated solution containing 24 grams alum and 2000 grams water at 90‹C and heating the resultant slurry. Polyvinyl chloride latex at 70‹C was then allowed to flow slowly into the agitated slurry from a pressurised bomb, the temperature of the slurry being maintained always above 155‹C to produce a polyvinyl chloride coating on the surface of the slurried elastomer crumbs. |
