Patent GB-218247-A (GB)
Title: Improved process for treating rubber and the like and products obtained thereby
IPC: C08L7/00
Filed: 1924-04-15
Abstract: 218,247. Naugatuck Chemical Co., (Assignees of Cadwell, S. M.). June 25, 1923, [Convention date]. Vulcanizing.-In the vulcanization of rubber &c., prevulcanization is prevented, the rate of vulcanization of various samples of rubber is rendered uniform, a check may be imposed during the process, and over vulcanization prevented by the addition to rubber or a rubber composition, of a substance which reacts with one of the vulcanizing ingredients, vulcanizing ingredient being defined as a component of a compound or mixture capable of effecting vulcanization. The reaction product may remain in the rubber. The invention is particularly applicable, but not limited to the process described in Specifications 200,788, and 200,789 in which vulcanization is effected by the addition of four ingredients viz. : a metal in combination, an amine., sulphur, and carbon disulphide or oxysulphide or their products. Substances may be added to check the action of any of these ingredients, and vulcanization may be resumed by the addition of a further quantity of the ingredient which has been reacted with, or merely by heat. For reacting with the amine, an acid anhydride, as phthalic anhydride, or nitroso bodies, as p-nitrosodimethylaniline, nitroso #-naphthol, p-nitrosodiethylaniline, or quinone, or aldehydes may be employed. Aldehydes can only be employed when the four ingredient process is used, otherwise they act as accelerators in presence of amine. These additions may be made to rubber to lower the basicity of nitrogenous matter, naturally occurring in the rubber, or with which the rubber may casually come into contact, as for example, aniline fumes in the factory, and may be added to raw rubbers to make the rate of vulcanization more uniform. For checking the action of the carbon-disulphidecontaining material an excess of an aliphatic amine, preferably primary, or ammonia, or hydrogen sulphide may be added. For checking the action of the zinc or other metal, hydrogen sulphide or similar substance to form a less active compound is employed, and for limiting the action of the sulphur in above process, an unsaturated body such as palm oil, resin, or pine tar is added. The invention may be applied when vulcanizing by permeation as described in Specification 174,915, and may be applied to rubber in any form, latex, raw rubber, or sprayed rubber as described in Specifications 157,975 and 157,978. The invention is also applicable when using the vulcanizing-ingredients described in Specification 177,493. Numerous examples are given in the Specification of which the following are typical, (a) 100 parts of rubber, 2 parts of zinc oxide, 2 parts of sulphur, 2 parts of oxynormalbutylthiocarbonicacid disulphide, and 0.3 parts of phthalic anhydride are milled together to form a compound which can be stored. Vulcanization is brought about by exposing the mix to amine, as aniline fumes or solution or diethylamine vapour, or by heat alone at 266‹ F. for 1 hour; (b) to latex preserved with 0.25 per cent ammonia sufficient to produce 100 parts of dry rubber, is added 1.5 parts of tetramethylthiuramdisulphide, 2 parts of zinc oxide, 3 parts of sulphur and 4 parts of ammonium sulphide. After coagulation, for example in the production of thread, vulcanization may be resumed by adding 2 parts of zinc oxide and 1.5 parts of tetramethylthiuramdisulphide and heating to 212‹ F. for 60 minutes.