Patent GB-715319-A (GB)
Title: Novel organopolysiloxane resin compositions and process for their manufacture
Inventor: PEYROT PIERRE PASCAL
IPC: C08K5/14
Filed: 1951-01-24
Abstract: A moulding composition with a long storage life but capable of being rapidly cured comprises an organo-polysiloxane resin, from 0.20 to 4 per cent. of one or more ethanolamines and from 1 to 6 per cent. benzoyl peroxide, the percentages being by weight of the resin. Mineral pigments, anti-adhesion agents and fillers, e.g. mica powder, titanium dioxide, aluminium oxide, talc, steatite, metallic titanates, glass fibres and asbestos, may be included in the composition.  The compositions may be made by mixing the ethanolamine, benzoyl peroxide and resin in a common solvent or mixture of solvents.  The resulting composition is then heated to bring about partial condensation of the resin to bring it to a suitable state for moulding and to remove the solvent. Alternatively the ingredients may be compounded without a solvent and the resin partially condensed by heating.  This condensation may be effected at about 100 DEG C. for a few minutes to a few hours. The products may be moulded at 160 DEG -170 DEG C. and 50-500 kg./em2 pressure and the moulded products after-heated, e.g. at 250 DEG C.  The addition of a mineral or organic acid such as sulphuric or abietic, e.g. 0.1 to 0.8 mol. per mol. ethanolamine may be advantageous, retarding the bodying of the resin in the preliminary heating.  In examples: (1) A methylpolysiloxane resin of CH3:Si ratio 1.25 in toluene is compounded with 3.8 per cent. of benzoyl peroxide, 2.73 per cent. of triethanolamine, glass fibres and titanium dioxide.  The composition is heated at 100 DEG C. for 45 minutes and moulded at 170 DEG C. for five minutes.  The store life of the composition is at least 40 days. (2) Similar to (1).  (3) Similar to (1) but using titanium dioxide asbestos fibre and calcium stearate in the composition.  (4) Similar to (1) but using a mixture of mono-, di- and tri-ethanolamines with the addition of colophony resin.  (5) A methyl/phenyl polysiloxane resin, derived by hydrolysis of a mixture of 33 per cent. methyltrichlorosilane, 7 per cent. di-methyldichlorosilane and 60 per cent. phenyltrichlorosilane (R:Si ratio 1:1), is compounded in toluene with 2.92 per cent. benzoyl peroxide, 1.25 per cent. of a mixture of di- and triethanolamine, colophony, titanium dioxide and glass fibres.  The composition is heated at 100 DEG C. for 30 minutes.  The store life is at least three months.  (6) Similar to (4) but using triethanolamine only.  (7) Similar to (5) using triethanolamine only.  (8) Similar to (7) with the addition of diatamaceous powdered silica and aluminium stearate.  (9) The resin solution of example (1) is mixed with methanol, titanium dioxide and glass fibres, the solvent evaporated and more resin solution containing benzoyl peroxide are mixed in together with a solution of colophony, di- and tri-ethanolamine.  The composition, after drying at room temperature and then at 100 DEG C., is similar to that of example (1).  (10) The resin solution of example (1) is mixed with benzoyl peroxide, aluminium stearate, sulphuric acid dispersed in methanol and diethanolamine in methanol.  The composition is dried at 100 DEG C. and has properties similar to those of example (1).