Patent GB-1433288-A (GB)
Title: Thermally curable compositions and process for curing said compositions
IPC: C07F7/08
Filed: 1974-04-30
Abstract: 1433288 Isocyanurate containing organo silicon polymers HITACHI Ltd 30 April 1974 [2 May 1973 (2)] 18950/74 Headings C3T C3S and C3P A thermally curable composition consists essentially of (a) at least one silane or siloxane having at least 2 silicon-bonded hydrogen atoms and (b) at least one trialkenyl isocyanurate or dialkenyl isocyanurate and optionally an addition polymerization catalyst alone or together with a radical polymerization catalyst. Suitable trialkenyl isocyanurates are presented by the formula where R 3  is a direct bond or organic group and R 4 -R 6  are each hydrogen, halogen or an alkyl group. Suitable dialkenyl isocyanurates are obtained by replacing one of the alkenyl substituents in the above formula by an alkyl, silylalkyl or aryl group. Suitable components (b) are trivinyl-, triallyl-, tricrotyl-, trimethacryltrichloropropenyl- or tributadienyl - isocyanurate. Suitable components (a) are silanes such as SiH 4 , H 2 SiCl 2 , C 6 H 5 SiH 3 , C 5 H 11 SiH 3  and various dimethylsiloxanes dimethyldiphenylsiloxanes and methylhydrogen siloxanes each containing at least 2 Si-H groups. Preferably 0À2-1À2 equivalents of (a) are blended with 1 equivalent of (b). The compositions can be cured either by heating to 200-100 C. in the absence of a catalyst, or by heating to 50-250 C. in the presence of 10<SP>-6</SP>-10<SP>-4</SP> mole per equivalent of Si-H groups in (a) of an addition polymerization catalyst and optionally further heating in the presence of 0À2-5% wt. of a radical polymerization catalyst at a temperature above the thermal decomposition temperature of the catalyst up to 400 C., or by effecting the addition and polymerization reactions simultaneously. Suitable addition polymerization catalysts are Lewis acids, organic bases, palladium-alumina, Raney nickel, Pt, peroxides, U.V. or gamma rays. Suitable radical polymerization catalysts are organo peroxides and azo compounds. The composition may comprise a filler such as silica, alumina, glass, talc, zircon and quartz glass and an organic solvent. In Example 1 0À5 mole triallyl isocyanurate (a) is reacted with 0À25 mole tetramethyldisoloxane (b) in the presence of chloroplatinic acid to yield a product of the formula which was then either cured by heating in the presence of dicumyl peroxide or by reaction with pentamethylcyclopentasiloxane in the presence of chloroplatinic acid (Example 5); in Example 2 0À6 mole triallyl isocyanurate is reacted with 0À4 mole tetramethyldisiloxane as in Example (1) to yield a product containing unreacted alkenyl groups; in Example 3 0À1 mole tetramethyldisiloxane is reacted with 0À34 mole of triallylisocyanurate in the presence of a Pt/alumina catalyst to yield a product of the formula which was either reacted with triallyl isocyanurate (Example 6) or with the product of Example 2 (Example 7) in the presence of chloroplatinic acid. In Examples 4 and 8 triallyl isocyanurate (1, e.g.) is reacted with either pentamethylcyclopentasiloxane or tetramethylcyclotetrasiloxane in the presence of chloroplatinic acid. In Example 10, 1À1 moles of triallylisocyanurate were reacted with 1 mole of tetramethyldisiloxane as in Example 1 to yield a product of the formula where n = 9 which was then reacted with triallyl  isocyanurate in the presence of dicumyl peroxide.