GB640067A - Improvements in and relating to synthetic elastic and elastomeric products - Google Patents

Abstract

An elastic product, which may be cured to give an elastomer, comprises a polysiloxane containing both the structural unit -(CH3)2.SiO-and the structural unit -CH3.H.Si.O-, which has been treated with ferric chloride, an alkali metal hydroxide, sulphuric acid or phenyl phosphoryl chloride, as elasticizing agent. The initial polysiloxane may be prepared by the cohydrolysis of a mixture of the corresponding hydrolysable silanes containing from 50 or 70 to 97 mol. per cent of a dimethylsilane using water or by admixing the separate hydrolysis products. The initial polysiloxane is contacted with 0.5 to 5 per cent by weight of the elasticizing agent, and allowed to stand at room temperature or heated to give an elastic product. This may be compounded with vulcanizing agents and fillers, e.g. titanium dioxide, ferric oxide, antimony oxide, asbestos, comminuted glass fibres, whiting, lithopone, tale, zinc oxide, powdered silica, and cured to an elastomeric composition. In examples, dimethyldichlorosilane and methydichlorosilane as mixtures in varying proportions were hydrolysed and treated with phenyl phosphoryl chloride to give an elastic gum which was compounded with titanium dioxide and, optionally, with benzoyl peroxide to give various elastomeric compositions. Specifications 575,667, 594,481, 594,506, 618,452 and 629,642 also are referred to.