GB624361A - Improvements in or relating to organo-silicon compounds - Google Patents

Abstract

An allyl silicon resin is prepared by hydrolysing an organo silicon compound of the general formula <FORM:0624361/IV (a)/1> wherein x is a number from 1 to 2, z is from 0 to 2, the sum of x and z not exceeding 3, R represents a hydrocarbon group which will not undergo a vinyl type of polymerization, and Y represents chlorine or an ethoxyl radical, and dehydrating and condensing the resulting silicol to form a silicone. Polymerization through the p unsaturated allyl group may also take place. The dehydration is preferably carried out in the presence of a dehydrating agent, e.g. boric acid esters such as methyl borate, metal halides, the oxides and halides of phosphorus or sulphuric or hydrochloric acid. The methallyl silicones may be added to alkyl or aryl silicones. Interpolymers are obtained by carrying out the above hydrolysis, dehydration and condensation in the presence of one or more saturated organic silicon compounds of the general formula RxSiY4-x, where R is a non-polymerizing hydrocarbon group such as an alkyl, phenyl or alkyphenyl group, and Y is a halide or ethoxy group, or by dehydrating and condensing a mixture of the corresponding silicols or by mixing the corresponding silicones or solutions thereof when they are liquids due to a low degree of polymerization and heating. The condensation may be continued only until a solvent soluble polymer is obtained which may then be dissolved in a volatile liquid carrier such as a hydrocarbon, or may be dispersed in a volatile liquid carrier such as water with the aid of ammonia or a dispersing agent such as a sodium alkyl sulphonate ester, or a hydrolysed polyvinyl ester and a simple alcohol such as ethyl alcohol. Finely-divided inorganic materials may be added to the silicone polymers of interpolymers, e.g. silica flour, bentonite, glass powders, calcium fluoride, ceramic powders, graphite, anthracite, coal, or petroleum coke. In an example, a mixture of methallyl silicon triethoxide, methyl silicon triethoxide and dimethyl silicon diethoxide is hydrolysed with sulphuric acid in the presence of toluene to yield a silicone dissolved in toluene. The Specification mentions that methallyl silicon chlorides and methallyl silicon ethoxides may be polymerized directly to form resinous bodies by heating in the presence of a catalyst, e.g. methallyl silicon triethoxide may be polymerized by heating in the presence of a catalyst such as tertiary butyl perbenzoate. Allyl esters such as allyl phthalate or allyl carbonate may be polymerized in the presence of methallyl silicon ethoxides. Specifications 596,668, 624,363 and 624,364 are referred to.ALSO:Organo silicon compounds of the general formula <FORM:0624361/IV (b)/1> wherein x represents 1 or 2, R represents a saturated hydrocarbon group, z represents 0, 1 or 2, the sum of x and z not exceeding 3 and Y represents chlorine or an ethoxyl radical, are prepared by treating ethyl orthosilicate or silicon tetrachloride with a Grignard reagent to substitute the desired methallyl and saturated hydrocarbon groups for the chlorine or ethoxy groups. The products may be hydrolysed to the corresponding silicols which may then be dehydrated and condensed to form a silicone. The products may also be mixed with organosilicon compounds of the general formula R1nSiY4-n, wherein R1 represents a saturated hydrocarbon group, Y is a halide or ethoxyl radical and n is a number from 1 to 3, hydrolysing the mixture and dehydrating and condensing the resulting silicol. By saturated hydrocarbon group is meant a hydrocarbon group which will not undergo a vinyl type of polymerization, e.g. alkyl or phenyl radicals. In an example, dimethallyl silicon diethoxide and methallyl silicon triethoxide are prepared by means of a Grignard reaction and then by reaction with a further Grignard reagent methyl, phenyl, chlorophenyl, fluorophenyl and other alkylphenyl radicals may be introduced for one or two ethoxyl groups on the silicon atom. Specifications 596,668, 624,363 and 624,364 are referred to.ALSO:Plastic compositions comprise mica flakes or inorganic fibrous materials such as asbestos, cloth or glass fibres bound together with a methallyl silicone as obtained by hydrolising, condensing and dehydrating an organic silicon compound of the general formula <FORM:0624361/V/1> wherein x is a number from 1 to 2, R represents a hydrocarbon group which will not undergo a vinyl type of polymerisation, Z is from 0 to 2. The sum of X and Z not exceeding 3, and Y represents chlorine or an ethoxyl radical, or with a methallyl silicone interpolymer as obtained by carrying out the above hydrolysis, dehydration and condensation in the presence of one or more organic silicon compounds of the general formula R1n-Si-Y (4-n), wherein R is a non-polymerising hydrocarbon radical, N is from 1 to 3 and Y is a holide or an ethoxyl radical. Specifications 596,668, [Group IV], 624,363 and 624,364 are referred to.