GB748972A - Improvements in rubber treatment - Google Patents

Abstract

A vulcanized rubber is obtained by mixing a synthetic rubbery polymer of an aliphatic conjugated diene with a relatively large amount of rubber reinforcing carbon black and a relatively small amount of hexachlorocyclopentadiene, heating the mixture at a temperature above 275 DEG F., thereafter incorporating vulcanizing and other ingredients, shaping the mass, and vulcanizing it. The black is preferably used in an amount of 40 to 100 parts per 100 parts of rubber and the hexachlocyclopentadiene from 0.5 to 3.0 parts. The synthetic rubber may be a polymer of isoprene or butadiene, or a copolymer of one of these monomers with styrene, acrylonitrile, monovinylpyridine, methyl acrylate, or methyl methacrylate; or butyl rubber. In example (2) 100 parts of butyl rubber, 50 parts of carbon black and 0.5-1.5 parts of hexachlorocyclopentadiene are mixed and heated to 325-375 DEG F. for 15 minutes. Then 3 parts of stearic acid, 3 parts of zinc oxide, 1 part of tetramethylthiuram disulphide, 0.5 parts of 2-mercaptobenzthiazole and 2 parts of sulphur were added and the whole vulcanized for 60 minutes at 293 DEG F. In example (4), a similar mix is used in which the synthetic rubber is a butadiene-styrene copolymer and the mix contains diphenylguanidine. Reference has been directed by the Comptroller to Specification 725,634.ALSO:A vulcanized rubber is obtained by mixing natural rubber with a relatively large amount of rubber reinforcing carbon black and a relatively small amount of hexachlorocyclopentadiene, heating the mixture at a temperature above 275 DEG F., thereafter incorporating vulcanizing and other ingredients, shaping the mass, and vulcanizing it. The black is preferably used in an amount of 40 to 100 parts per 100 parts of rubber and the hexachlocyclopentadiene from 0.5 to 3.0 parts. In Example 1, 100 parts of rubber, 50 parts of carbon black and 5 parts of stearic acid are mixed, and 0.5 to 2.7 parts of hexachloropentadiene added and the mix heated to 300 DEG F. and masticated for 10 minutes. After cooling to 200 DEG F. 2 parts of pine tar, 2 parts of zinc oxide, 1 part of antioxidant, 1 part of accelerator and 3 parts of sulphur are added and the whole vulcanized at 287 DEG F. for 45 minutes. Reference has been directed by the Comptroller to Specification 725,634.