Polysulphide rubbers
AssigneeLondon Hospital Medical College
InventorMichael Braden
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Abstract
A catalyst composition, suitable for the ambient temperature curing of polysulphide rubbers, comprises zinc carbonate, an organic sulphur-containing accelerator containing a disulphide linkage (e.g. a thiazole, thiuram or dithiocarbamate), and a sulphur/amine complex. The composition contains from 15 to 90% by weight, based on the weight of zinc carbonate, of the organic accelerator and the sulphur/amine complex is preferably a sulphur/dialkylamine complex, the weight ratio of sulphur to amine in the sulphur/amine complex preferably being from 20 : 1 to 5 : 1 and the sulphur/amine complex being present in the composition in an amount of from 0.2 to 8% by weight, based on the weight of zinc carbonate.
Claims19
A catalyst composition, suitable for the ambient temperature curing of polysulphide rubbers, comprising zinc carbonate, from 15 to 90% by weight, based on the weight of zinc carbonate, of an organic sulphur-containing accelerator containing two sulphur linkages and from 0.2 to 8% by weight, based on the weight of zinc carbonate, of a sulphur/amine complex.
An ambient temperature curable composition comprising a polysulphide rubber together with a curing composition therefor comprising from 15 to 75% by weight of zinc carbonate, based on the weight of polysulphide rubber, from 15 to 90% by weight, based on the weight of zinc carbonate, of an organic sulphur-containing accelerator containing two sulphur linkages, and from 0.1 to 5% by weight, based on the weight of polysulphide rubber, of a sulphur/amine complex.
A method of producing a cured polysulphide rubber composition which comprises mixing the rubber with from 50 to 120% by weight, based on the weight of the rubber of a curing composition comprising zinc carbonate, from 15 to 90% by weight, based on the weight of zinc carbonate, of an organic accelerator containing two sulphur linkages and from 0.2 to 8% by weight, based on the weight of zinc carbonate, of a sulphur/amine complex and subsequently allowing the mixture to cure at ambient temperature.
Dependencies are inferred from the claim text.