Patent GB-719437-A (GB)
Title: Organopolysiloxane compositions
IPC: B01D19/04
Filed: 1952-11-13
Abstract: A composition which burns with difficulty and is suitable as a lubricant or hydraulic fluid comprises a compatible mixture of (1) 30-60 per cent. by weight of a halogenated aliphatic hydrocarbon having a boiling point of at least 150 DEG C. at atmospheric pressure and an empirical formula CaHbXcFd, where a is 4 or 5, b is 0 or 1, c is an integer from 4 to 7 inclusive, d is an integer from 2 to 6 inclusive, the sum of b+c+d having a minimum value of 8 and a maximum value of 2a + 2, and X is chlorine or bromine, (2) 0-15 per cent. of di (2-ethyl-hexyl) sebacate and (3) 25-70 per cent. of a liquid organopolysiloxane containing repeating units of the general formula RR1SiO where R and R1 are the same or different and are each a methyl, chlorophenyl, dichlorophenyl or phenyl radicle, at least 80 per cent. of the organic radicles in the polymer being methyl, and the siloxane having an average degree of substitution of from 1.9 to 2.3 organic radicles attached to silicon per silicon atom.  The composition may also contain oxidation inhibitors, viscosity stabilizers, rust inhibitors and lubricity improvers.  The composition may also be thickened with soaps, such as lithium stearate, or carbon black or silica, in order to obtain greases.  In the examples compositions are described which consist of (a) trimethylsiloxy end-blocked dimethylpolysiloxane (siloxane A), trimethylsiloxy end-blocked copolymer of dimethyl-and phenyl-methyl-siloxane (siloxane B) and a mixture of isomers of empirical formula C5 Cl5 F2 or C5 Cl5 F3, (b) siloxane A, di(2-ethyl-hexyl) sebacate and C4Cl5F4 or a mixture of isomers of empirical formula C5HCl5F4 or C4Br4F5 or C4Cl4F4Br2, (c) siloxane B, di(2-ethyl-hexyl) sebacate and a mixture of isomers of empirical formula C5Cl5F3 or C4Cl4F4Br2, (d) siloxane B and a mixture of isomers of emfirical formula C5Cl5F3 and (e) a copolymer obtained by co-hydrolyzing Me3SiCl, Me2SiCl2, ClC6H4MeSiCl2 and Cl2C6H3SiCl3, and a mixture of isomers of empirical formula C5Cl5F3.ALSO:A composition which burns with difficulty and is suitable as a lubricant comprises a compatible mixture of (1) 30-60 per cent. by weight of a halogenated aliphatic hydrocarbon having a boiling point of at least 150 DEG C. at atmospheric pressure and an empirical formula Ca Hb Xc Fd, where a is 4 or 5, b is 0 or 1, c is an integer from 4 to 7 inclusive, d is an integer from 2 to 6 inclusive, the sum of b+c+d having a minimum value of 8 and a maximum value of 2a+2, and X is chlorine or bromine, (2) 0-15 per cent. of di(2-ethyl-hexyl) sebacate and (3) 25-70 per cent. of a liquid organopolysiloxane containing repeating units of the general formula RR1SiO where R and R1 are the same or different and are each a methyl, chlorophenyl, dichlorophenyl or phenyl radicle, at least 80 per cent. of the organic radicles in the polymer being methyl, and the siloxane having an average degree of substitution of from 1.9 to 2.3 organic radicles attached to silicon per silicon atom.  The composition may also contain oxidation inhibitors, viscosity stabilizers, rust inhibitors and lubricity improvers.  The composition may also be thickened with soaps, such as lithium stearate, or carbon black or silica, in order to obtain greases.  In the examples, compositions are described which consist of (a) trimethylsiloxy end-blocked dimethylpolysiloxane (siloxane A), trimethylsiloxy end-blocked copolymer of dimethyl- and phenylmethylsiloxane (siloxane B) and a mixture of isomers of empirical formula C5Cl6F2 or C5Cl5F4,(b) siloxane A, di(2-ethyl-hexyl) sebacate and C4Cl6F4 or a mixture of isomers of empirical formula C5HCl5F4 or C4BR4F6 or C4Cl4F4Br2, (c) siloxane B, di(2-ethyl-hexyl) sebacate and a mixture of isomers of empirical formula C5Cl5F3 or C4Cl4F4Br2, (d) siloxane B and a mixture of isomers of empirical formula C5Cl5F3 and (e) a copolymer obtained by cohydrolysing Me3SiCl, Me2SiCl2, ClC6H4\t MeSiCl2 and Cl2C6H3SiCl3, and a mixture of isomers of empirical formula C5Cl5F2.