Improvements in or relating to the compounding of rubber compositions

摘要

A non-dusting solid composition for use in compounding synthetic rubber comprises a solid vulcanization accelerator and/or a solid rubber antioxidant in admixture with polybutene or hydrogenated polybutene, each of which has a molecular weight of between 500 and 5000. The polybutene preferably is used in an amount of 0.5 to 20.0 per cent based on the weight of the accelerator or antioxidant. The polybutene may be added in the solid state or as an emulsion made with the aid of a dispersing agent such as triethanolamine oleate. Agglomeration may be effected by extrusion, fin drum flaking or low pressure moulding. Accelerators specified are dithiocarbamates, thiuram sulphides, guanidines, thiazoles and thiazolines, aldehyde-amine condensation products and imidazolines, phenyl-naphthylamines, N,N1-dinapthyl - p - phenylenediamine, sym. diphenyl-p-phenylenediamine, bis-(2-hydroxy)-3-tert-butyl-5-methyl phenylmethane or the reaction product of acetone and diphenylamine or p-aminobiphenyl. In examples, the composition is added to a master batch consisting of GR-S, zinc oxide, softener and sulphur. Calcium carbonate, titanium dioxide, and whiting may also be included.ALSO:A non-dusting solid composition for use in compounding natural and synthetic rubber comprises a solid vulcanization accelerator and/or a solid rubber antioxidant in admixture with polybutene or hydrogenated polybutene each of which has a molecular weight of between 500 and 5000. The polybutene preferably is used in an amount of 0.5 to 20.0 per cent based on the weight of the accelerator or antioxidant. The polybutene may be used as such or may be emulsified with the aid of a dispensing agent such as triethanolamine oleate and then added to the accelerator or antioxidant in the solid state or in emulsion. Agglomeration may be effected by extrusion, fin drum flaking or low pressure moulding. A large number of accelerators are specified, these may be grouped as dithiocarbamates, thiuram sulphides, guanidines, thiazoles and thiazolines, aldehydeamine condensation products and imidazolines; and phenyl-naphthylamines, N, N1-di-naphthyl-p-phenylenediamine, sym diphenyl-p-phenylenediamine, bis-(2 hydroxy)-3-tert-butyl-5-methyl phenylmethane or the reaction product of acetone and diphenylamine or p-aminobiphenyl. In examples a mix prepared according to the invention was added to a master batch consisting of smoked sheet rubber, peptising agent, antioxidant, stearic acid, light process oil, zinc oxide, ground whiting, clay and carbon black or to a master batch consisting of GR-S, zinc oxide, softener and sulphur. Calcium carbonate, titanium dioxide, and whiting may also be added.