| 摘要 |
1534108 Silicone rubber compositions containing fibrous slag dust DOW CORNING CORP 22 Feb 1977 [19 May 1976] 07338/77 Heading C3T A silicone rubber composition comprises (A) 100 p.b.w. of a hydroxy- or triorganosiloxane-terminated polydiorganosiloxane gum in which at least 50% of the organic radicals are Me, at most 2% are Vi, and any others are Ph, Et or CF 3 CH 2 CH 2 -; (B) 25-75 p.b.w. of a reinforcing silica filler, (C) 5-20 p.b.w. of an organosilicon compound having two organic radicals per Si atom, of which radicals 10-50% are Ph, 2-20% are Vi and the rest are Me, and two Si-bound OH groups per molecule forming at least 3 wt. per cent of the compound, and (D) 20-80 p.b.w. of blast furnace slag fibres of 0À1-0À5 mm. length and 10-100 microns diameter. There may also be present (E) 0-10 p.b.w. of a silicon compound containing at least 25 wt. per cent of MeO, EtO and/or PrO groups any other organic radicals being Me, Et and/or Vi, (F) 0-10 p.b.w. of MgO and (G) 0-50 p.b.w. of an extending filler. In the Examples (A) 100 p.b.w. of a vinyl-terminated polydimethylsiloxane gum having 0À21-0À33% MeViSiO units is mixed with (B) 45 p.b.w. of fume silica, (C) 7-10 p.b.w. of a polydimethylsiloxane diol optionally having MeViSiO units and 1 p.b.w. of a further methyl vinyl siloxane diol and 0 to 4 p.b.w. of diphenylsilane diol, with 0 to 2.3 p.b.w. of fume TiO 2 and 0-0À5 p.b.w. ammonium carbonate; the mixture is then heated for 1 hour at 120‹ C. or 3 hours at 170‹ C.; (D) 50 p.b.w. of slag fibre dust, (E) 4-7À5 p.b.w. of MeSi(OMe) 3 or ethyl silicate and (F) 3 or 6À5 p.b.w. of MgO are added each either before or after the heating; finally 2,5-bis (tertbutyl peroxy)-2,5-dimethylhexane and Fe 2 O 3 and optionally zinc borate are added, and the composition is cured. |
