| abstract |
1286979 Methyl higher alkyl polysiloxanes and greases GENERAL ELECTRIC CO 15 Sept 1969 [16 Sept 1968] 45359/69 Headings C3T and C3S [Also in Division C5] A silicone grease comprises, by weight, (1) 61-98% of a liquid polysiloxane of average unit formula wherein the sum n + m + p + q is 2À002-3À0, n is 0À5-1À95, m is 0À5-1À0, p is 0-0À5, q is 0 to (m+n+p+q), R is a C 6-12 alkyl radical, R<SP>1</SP> is a t-butyl-substituted hindered hydroxyaryl radical, R<SP>11</SP> is a C 1-5 alkyl radical, C 5-7 cycloalkyl radical, a mono- or bi-nuclear aryl radical, a mononuclear aryl C 1-5 alkyl radical or a halo derivative of one of these, (2) 2-35% of a thickener, (3) optionally 0À01-5% of a polyether, (4) optionally sufficient base to give an alkaline grease. The polysiloxane (1) is preferably of 10-100,000 cS./25 C. viscosity. Many suitable thickeners are listed, including metal soaps of C 8 + carboxylic acids and other acids, finely divided oxides of Si, Al, Fe, Ti or Zn, glass fibres and clays, acylureas, phenylenediamides, phthalocyanines, carbon black, graphite and polyethylene. In Examples 1-3 the compound with decease-1 or dodecene-1 is added, in the presence of a Pt catalyst, to a polysiloxane Me 3 SiO(MeHSiO) 6 SiMe 3 [Example 1] or Me 3 SiO(MeHSiO) 60 SiMe 3 [Example 2] or Me 3 SiO(MeHSiO) 5 (MePhSiO)SiMe 3 [Example 3]. The product siloxanes are mixed with Li myristate, an adduct of propylene oxide (32 mols.) and ethylene oxide (96 mols.) to pentacrythritol, N-phenyl-alpha-naphthylamine and LiOH. The product siloxane of Example 1 is also mixed with the same polyether, fume silica, pentacrythritol and trimethoxyboroxine [Example 4], or the same polyether and carbon black and LiPH [Example 5] or with powdered graphite [Example 6]. |