Patent GB-372623-A (GB)
Title: Improvements in or relating to the manufacture of vulcanised rubber
IPC: C08K5/00
Filed: 1931-07-14
Abstract: Substances useful as rubber vulcanization accelerators are produced by interaction of mercaptobenzthiazoles, dithiocarbamates, and alkylxanthic acids having more than three carbon atoms per molecule, and their respective homologues and simple substitution derivatives, with a monohalogen acetic acid and treatment of the products with metallic salts of Group IIb of the Periodic system, particularly zinc salts.  The monohalogen acetic acid is preferably reacted in the form of an alkali metal salt; alternatively instead of the acid or salt may be used an ester of a halogen substituted derivative of formic or acetic acid, and the ester radicle removed by saponification during or after the initial condensation.  In a modification such substances may be prepared by interaction of the mercaptobenzthiazoles, dithiocarbamates, and alkylxanthic acids with the salts formed by the monohalogen acetic acids and the metals of Group IIb of the Periodic system, such as zinc chloracetate.  In examples (1) monochloracetic acid is reacted with 2-mercaptobenthiazole and the product treated with zinc chloride to give benzthiazyl-2-zinc thioacetate and (2) ethyl chloroformate is reacted with 2-mercaptobenzthiazole, the product saponified and treated with zinc chloride to give benzthiazole-2-zinc thiocarboxylate.ALSO:Substances useful as rubber vulcanization accelerators are produced by interaction of mercaptobenzthiazoles, dithiocarbamates, and alkylxanthic acids having more than three carbon atoms per molecule, and their respective homologues and simple substitution derivatives, with a monohalogen acetic acid and treatment of the products with magnesium salts.  The monohalogen acetic acid is preferably reacted in the form of an alkali metal salt; alternatively instead of the acid or salt may be used an ester of a halogen substituted derivative of formic or acetic acid, and the ester radicle removed by saponification during or after the initial condensation.  Such substances may also be prepared by reacting the mercaptobenzthiazoles, dithiocarbamates, and alkylxanthic acids with the magnesium salt of a monohalogen acetic acid.ALSO:Rubber compositions containing a vulcanizing agent such as sulphur are vulcanized by incorporating an accelerator produced by the interaction of mercaptobenzthiazoles, dithiocarbamates, and alkylxanthic acids having more than three carbon atoms per molecule, and their respective homologues and simple substituted derivatives, with a monohalogen acetic acid and treatment of the products with metallic salts of Group IIb of the Periodic system, particularly zinc salts.  The mono-halogen acetic acid is preferably reacted in the form of an alkali metal salt; alternatively there may be used instead of the acid or the salt, an ester of a halogen substituted derivative formic or acetic acid, and the ester radicle removed by saponification during or after the initial condensation.  In a modification the accelerators to be incorporated into the rubber compositions are produced by interaction of the mercaptobenzthiazoles, dithiocarbamates, and alkylxanthic acids with the salts formed by the monohalogen acetic acids and the metals of Group IIb of the Periodic system, such as zinc chloracetate.  In examples rubber mixes are described in which are incorporated (1) zinc 2-benzthiazyl-thioacetate prepared by reacting monochloracetic acid with 2-mercaptobenzthiazole and precipitating the zinc salt by means of zinc chloride, and (2) benzthiazole-2-zinc thiocarboxylate prepared by reacting mercaptobenzthiazole with ethyl chloroformate, saponifying and adding zinc chloride. Specification 353,871 is referred to.