GB793548A - Improved vulcanisation process for rubber - Google Patents

Abstract

In a process for vulcanizing synthetic rubber there is prepared a vulcanizable mix comprising the rubber, a reinforcing type furnace black, sulphur as essential vulcanizing agent, an accelerator, and an N : N1-thio-bis-morpholine, preferably N : N - monothio - bis - morpholine or N : N-dithio-bis-morpholine in an amount of 0.5 per cent by weight of the synthetic rubber. The amount of sulphur is preferably between 2 and 3 per cent, and that of accelerator up to 1.5 per cent, by weight of the synthetic rubber, which may be selected from polymers of butadiene-1,3, 2-methybutadiene-1,3, isobutene and copolymers of these compounds with acrylonitrile, styrene, methyl methacrylate, and other compounds copolymerizable therewith. The accelerator is preferably of the delayed action type, e.g. a thiazole sulphenamide such as N-tert.-butyl, N-tert.-octyl or N-cyclohexyl benzthiazyl sulphenamide, or benzthiazyl sulphenmorpholide or sulphenpiperide, or a substituted mercaptobenzthiazole such as 2 : 4-dinitrophenyl-2-benzthiazyl monosulphide, ethylbenzthiazyl disulphide, or 2 : 21-dibenzthiazyl disulphide. The N : N1-thio-bis-morpholine and the accelerator may be incorporated into the synthetic rubber mix as a previously blended mixture. Examples are described. Specification 711,236 is referred to.ALSO:In a process for vulcanizing natural or synthetic rubber there is preferred a vulcanizable mix comprising the rubber, a reinforcing type furnace black, sulphur as essential vulcanizing agent, an accelerator, and an N; N1-thiobis-morpholine, preferably N; N1-monothio-bis-morpholine or N; N1-dithio-bis-morpholine in an amount of 0,5 per cent by weight of the rubber. The amount of sulphur is preferably between 2 and 3 per cent and that of accelerator up to 1,5 per cent, by weight of the rubber. As examples of synthetic rubbers are specified polymers of butadiene 1, 3, 2-methylbutadiene 1, 3, isobutene and copolymers of these compounds with acrylonitrile, styrene, methylmethacrylate, and other compounds copolymerizable therewith. The accelerator is preferably of the delayed action type, e.g., a thiazole sulphenamide such as N-tert. butyl, N-tert-octyl or N-cyclohexyl benzthiazyl sulphenamide, or benzthiazyl sulphenmorpholide or sulphenpiperide, or a substituted mercaptobenzthiazole such as 2 : 4-dinitrophenyl-2-benzthiazyl monosulphide, ethylbenzthiazyl disulphide, or 2; 21-dibenzthiazyl disulphide. The N; N1 thio-bis-morpholine and the accelerator may be incorporated into the rubber mix as a previously blended mixture. Several examples are described. Specification 711,236 is referred to.