Patent GB-807503-A (GB)
Title: Organopolysiloxane compositions
IPC: C10M169/00
Filed: 1956-06-06
Abstract: A composition which is relatively non-flammable and is useful as a lubricant comprises (1) 25 to 70 per cent by weight of a liquid polysiloxane containing the repeating units (R R1 Si O), where R and R1 are monovalent hydrocarbon or halogenated hydrocarbon radicals of 1 to 7 carbon atoms and free of acetylenic linkages, at least 80 molar per cent of the organic radicals in the polymer being methyl, and the polymer having 1.9 to 2.3 organic radicals per silicon atom; (2) 30 to 60 per cent of an aliphatic halofluorocarbon of empirical formula CaHbXcFd, where a is 4 or 5, b is 0 or 1, c is 4, 5, 6 or 7, d is 2, 3, 4, 5 or 6, b+c+d has a value between 8 and 2a+2 inclusive, and X is Cl or Br, the fluorocarbon having a boiling-point of at least 150 DEG  C.; (3) 0 to 15 per cent of an alkyl diester of an aliphatic dicarboxylic acid having 4 to 10 carbon atoms exclusive of the carboxylic groups, each alkyl group having 2 to 10 carbon atoms; (4) 0.043 to 0.86 per cent of an anhydride of alkyl- or alkenyl-succinic or -glutaric acid, the alkyl and alkenyl groups containing 8 to 23 carbon atoms; (5) 0.043 to 0.86 per cent of an alkyl diester of the acid anhydride of (4) in which the alcohol residue contains 1 to 4 carbon atoms; and (6) 0.014 to 0.28 per cent of benzotriazole.  The siloxanes may be homo- or co-polymers or mixtures, and the organic radicals therein may be alkyl, cycloalkyl, aryl or alkenyl or their halogenated derivatives.  The preferred polymer is a trimethylsiloxy end-blocked dimethyl polysiloxane.  The halofluorocarbons are the chlorofluoro-, bromofluoro-, and chlorobromofluoro-substituted butanes, butenes, pentanes, pentenes and pentadienes.  The preferred compounds are isomers having the empirical formul  C5HCl5F4, C5Cl5F3, C5Cl6F2, C4F6Br4, C4Cl4F4Br2, and C4Cl6F4.  The optional esters of category (3) include diethyl adipate, dioctyl adipate, dibutyl pimelate, dihexyl suberate, didecyl azelate, di-(2-ethylhexyl) sebacate and the diethyl ester of dodecanedioic acid.  In the anhydrides of category (4), the alkyl or alkenyl groups may be substituted on any position in the molecule and include octyl, octenyl, 2-ethylhexyl, dodecenyl, octadecyl, octadecenyl and tricosanyl radicals.  Examples of the esters (5) are diethyl dodecenyl-, dibutyl 2-ethylhexyl-, diisopropyl octadecenyl-, di-tert.-butyl tricosanyl- and diethyl dodecyl-succinates, and the comparable glutarates.  The compositions may also contain oxidation and rust inhibitors, stabilizers and lubricity improvers.  They may also be thickened to form greases by adding soaps, e.g. lithium stearate, or carbon black or silica.  Specific examples are given of compositions which are compatible for long periods at low temperature, and have good lubricating power, hydrolytic and thermal stability and low viscosity - temperature slope. Specifications 719,437, 746,510 and 807,235, [both in Group IV (a)], are referred to.ALSO:A composition which is relatively nonflammable and is useful as an hydraulic fluid or lubricant comprises (1) 25 to 70 per cent by weight of a liquid polysiloxane containing the repeating units (RR1SiO), where R and R1 are monovalent hydrocarbon or halogenated hydrocarbon radicals of 1 to 7 carbon atoms and free of acetylenic linkages, at least 80 molar per cent of the organic radicals in the polymer being methyl, and the polymer having 1.9 to 2.3 organic radicals per silicon atom; (2) 30 to 60 per cent of an aliphatic halofluorocarbon of empirical formula CaHbXcFd, where a is 4 or 5, b is 0 or 1, c is 4, 5, 6 or 7, d is 2, 3, 4, 5 or 6, b+c+d has a value between 8 and 2a+2 inclusive, and X is Cl or Br, the fluorocarbon having a boiling-point of at least 150 DEG  C.; (3) 0 to 15 per cent of an alkyl diester of an aliphatic dicarboxylic acid having 4 to 10 carbon atoms exclusive of the carboxylic groups, each alkyl group having 2 to 10 carbon atoms; (4) 0.043 to 0.86 per cent of an anhydride of alkylor alkenyl-succinic or glutaric acids, the alkyl and alkenyl groups containing 8 to 23 carbon atoms; (5) 0.043 to 0.86 per cent of an alkyl diester of the acid anhydride of (4) in which the alcohol residue contains 1 to 4 carbon atoms; and (6) 0.014 to 0.28 per cent of benzotriazole.  The siloxanes may be homo- or co-polymers or mixtures, and the organic groups may be alkyl, cycloalkyl, aryl and alkenyl and their halogenated derivatives.  The preferred polymer is a trimethylsiloxy end-blocked dimethylpolysiloxane.  The halofluorocarbons are the chlorofluoro-, bromofluoro-, and chlorobromofluoro substituted butanes, butenes, pentanes, pentenes and pentadienes.  The preferred compounds are isomers having the empirical formul  C5HCl5F4, C5Cl5F3, C5Cl6F2, C4F6Br4, C4Cl4F4Br2, and C4Cl6F4. The optional esters of category (3) include diethyl adipate, dioctyl adipate, dibutyl pimelate, dihexyl suberate, didecyl azelate, di-(2-ethylhexyl) sebacate and the diethyl ester of dodecanedioc acid.  In the anhydrides of category (4), the alkyl or alkenyl groups may be substituted on any position in the molecule and include octyl, octenyl, 2-ethylhexyl, dodecenyl, octadecyl, octadecenyl and tricosanyl radicals.  Examples of the esters (5) are diethyl dodecenyl-, dibutyl 2-ethylhexyl-, diisopropyl octadecenyl-, di-tert.-butyl tricosanyl- and diethyl dodecyl succinates, and the comparable glutarates.  The compositions may also contain oxidation and rust inhibitors, stabilizers and lubricating improvers.  They may also be thickened to form greases by adding soaps, e.g. lithium stearate, or carbon black or silica.  Specific examples are given of compositions which are compatible for long periods at low temperatures, and have good lubricating power, hydrolytic and thermal stability and low viscosity-temperature slope. Specifications 719,437, 746,510 and 807,235 are referred to.