GB827375A - Improvements in preparation of polysulfide polymers - Google Patents

Abstract

Polysulphide polymers are prepared by (i) reacting one or more organic polyhalides comprising an aliphatic hydrocarbon or oxahydrocarbon radical having a maximum of four halide groups, with an aqueous inorganic thiosulphate solution; and then (ii) treating the resultant organic polythiosulphate solution with a mixture of water-soluble hydrosulphide and sulphide to produce the desired polymer, said mixture containing 0.002-2 mols. of hydrosulphide per mol. of monosulphide, and the molar ratio of the total sulphide equivalent of the mixture of water-soluble hydrosulphide and sulphide to the thiosulphate equivalent of the polythiosulphate being within the range of 0.4-0.65 : 1. In a preferred embodiment the polythiosulphates of (ii) are derived from the polyhalides of (i) in a proportion of 90-99 mol. per cent dihalides to 1-10 mol. per cent of tri- and/or tetra-halides, to provide polymers with the desired degree of cross-linking. Lists of haloethers, haloformals and halohydrocarbons are given, the following being particularly preferred: bis (b -chloroethyl) ether, bis (b -chloroethyl) formal, bis (d -chlorobutyl) formal, 1,2,3-trichloropropane and tetrachloropropylformal. The only sulphur compounds specified are all sodium salts, but the sulphides may be of higher rank than the monosulphide, e.g. Na2S1-2. The polymers may be cured with a mixture of TiO2, p-quinone dioxime, diphenyl guanidine, with or without sulphur; or with lead peroxide. Reference has been directed by the Comptroller to Specification 763,530.