GB1477371A - Compositions for use in processing rubber - Google Patents

Abstract

1477371 Processing aid for use in rubber compounding TECHNICAL PROCESSING Inc 31 Oct 1974 [1 Nov 1973 4 Dec 1973 3 Jan 1974] 47138/74 Heading C3Q A composition (of use as a processing aid in the compounding of rubber, whether natural, synthetic or reclaimed) comprises (a) at least one alkali metal or amine salt of an aromatic sulphonic acid having the formula wherein n is 0 or an integer of from 1 to 5 and any X is a straight chain or branched chain alkyl group containing from 4 to 14 carbon atoms, (b) at least one fatty acid containing not more than 22 carbon atoms in the chain, present in an amount by weight at least equal to the amount by weight of component (a) and (c) a thioether, preferably present in an amount of from 5 to 10 weight per cent based on the weight of component (a) and/or of from 1 to 3 weight per cent based on the combined weight of component (a) plug component (b). The thioether, which preferably has a boiling point above 130‹ C., may be a compound having the formula R 2 Y wherein each R is an alkyl, aryl, aralkyl or alkaryl group containing not more than 12 carbon atoms, which group may be interrupted by and/or substituted with at least one ethereal oxygen atom and/or at least one group selected from keto, carboxyl, ester, cyano, primary amine, secondary amine, tertiary amine and amide groups, and Y is a sulphur atom or a group having the formula wherein x is an integer of from 1 to 5. Preferred thioethers are thiodicarboxylic acids and alkyl esters thereof having the formula wherein a is 0 or 1, z is 1 or 2, Q is a hydrogen atom or an alkyl group containing from 1 to 3 carbon atoms and Y is as aforementioned. Specified thioethers are dibenzyl sulphide, thiodiglycolic acid, thiodipropionic acid, dimethyl thiodipropionate, thiodipropionitrile, thiodisuccinic acid and methylene bis-(thioacetic acid). The composition also may contain at least one additional compound selected from aromatic esters and ethers; compounds having alcoholic and/or glycolic hydroxyl groups; sodium and potassium soaps of fats and fatty acids; magnesium, calcium, barium and zinc soaps; and paraffin hydrocarbons, for example selected from mineral oil, mineral waxes, petrolatum and mixtures thereof. Numerous examples of suitable additional compounds are listed in the Specification. The composition may be solid or liquid; if the composition is liquid, metal soap is absent and the aromatic sulphonic acid salt is an amine salt which may be preformed or prepared in situ from an aromatic sulphonic acid and an amine having either the formula T 3 N wherein each T is a hydrogen atom or an alkyl or hydroxyalkyl group, with the proviso that at least one T is not a hydrogen atom, or the formula H-(-NHCH 2 CH 2 -)- m NH 2 wherein m is an integer of from 2 to 5. Specified compositions contain, as such additional compounds, diphenylphthalate, tetraethyleneglycol mono-nonylphenyl ether, tripropylene glycol, cetyl alcohol, potassium stearate, zinc oleate and petrolatum in respect of a composition wherein the aromatic sulphonic acid salt is an alkali metal salt and dipropylene glycol dibenzoate, tetraethylene glycol mono-nonylphenyl ether, tripropylene glycol and mineral oil in respect of a liquid composition wherein the aromatic sulphonic acid salt is an amine salt. The composition may be used in an amount of from 0À5 to 2 weight per cent based on the weight of rubber to be compounded. To the resulting mixture of rubber and composition may be added material selected from pigments, fillers and vulcanizing agents. Exemplified compositions contain the additional compounds specified supra in respect of the composition wherein the aromatic sulphonic acid salt is an alkali metal salt together with mixed isomers of potassium n-dodecylbenzene sulphonate, stearic acid and either no thioether (comparison Composition A) or thiodiglycolic acid (Composition B) or thiodipropionic acid (Composition C). Exemplified rubber compositions are prepared from crude natural rubber, finely-divided silica, carbon black, mineral oil, polytetrafluoroethylene plasticizer, microcrystalline wax, zinc oxide, stearic acid, benzothiazyl disulphide, sulphur accelerators and either comparison Composition A or Composition B or Composition C (Example 1) and from crude natural rubber, activated zinc salt of pentachlorothiophenol, mercaptobenzothiazole, benzothiazyl disulphide, tetraethylthiuram disulphide, zinc dimethyldithiocarbamate, zinc oxide, stearic acid, petrolatum, whiting, sulphur and Composition B (Example 2) and from pale crepe, stearic acid, zinc oxide, fine clay, alpha-pinese resin, sulphur, dibenzthiazyl disulphide and Composition C (Example 3).