| 摘要 |
<p>1326647 Vulcanizing rubber STAUFFER CHEMICAL CO 28 Sept 1971 [28 Sept 1970] 45103/71 Heading C3E [Also in Division C1] The dispersibility in rubber of insoluble sulphur is improved by mixing the sulphur with 0À3 to 5% by weight based on the total weight of sulphur of a dispersing aid of formula wherein R 1 is an alkyl group containing from 4 to 20 carbon atoms, R 2 is a hydrogen atom, or an alkyl group of from 4-20 carbon atoms and n is an integer from 4-100. Insoluble sulphur is defined as a sulphur containing at least 30% by weight of a sulphur which is a metastable linear polymer having more than 8 sulphur atoms/ polymer chain or such a sulphur which has been treated with an oil to prevent dusting during rubber processing. The mixture may be formed by merely agitating the two ingredients at or near room termperature, or by adding the sulphur to a solution of the dispersing aid in a solvent which does not affect the stability of the sulphur e.g. CS 2 and then evaporating the solvent. The above modified sulphur is used to vulcanize rubber wherever sulphur or insoluble sulphur can be used. The rubber used is defined as an unsaturated hydrocarbon elastomer requiring a sulphur cure and natural rubber, SBR, butadiene, acrylonitrile and EPDM are mentioned, natural rubber being exemplified. Other ingredients found in rubber blends viz antioxidants, processing aids, buffers, fillers, pigments and accelerators may be present.</p> |
