Patent GB-885731-A (GB)
Title: Improvements relating to synthetic lubricants
IPC: C22C13/02
Filed: 1958-05-01
Abstract: A lubricating composition, particularly suitable for use in aero gas turbines, comprises a blend of (1) a liquid aliphatic diester of a saturated aliphatic dicarboxylic acid and (2) a polyester, soluble in the diester, and having the formula HO(R2OOCR1COO)nR2OH wherein n is an integer, R1 is a C4-C14 alkylene group and R2 is the residue of a glycol HOR2OH which is a tricyclodecane dimethylol, the relative proportions of components (1) and (2) in the blend being such that the viscosity of the blend at 210 DEG F. is 4-30 centistokes. Component (1) may have the formula R4OOCR5COOR4 wherein R5 is a C4-C14 alkylene group and R4 is a C4-C18 alkyl group.  The composition may also contain an antioxidant (e.g. phenothiazine) or a crystallization suppressant (e.g. a polymerized alkyl ester of acrylic or methacrylic acid).  In an example, a composition is described consisting of (1) a blend of octyl nonyl sebacate, dioctyl sebacate and divonyl sebacate (prepared from equimolecular amounts of sebacic acid, 2-ethyl hexanol and 3,5,5-trimethyl hexanol, (2) a polyester prepared from sebacic acid, 2,2,4-trimethyl adipic acid, 2,4,4-trimethyl adipic acid and a commercial mixture of tricyclodecane dimethylol isomers and (3) phenothiazine.  For comparison purposes, a similar composition is described wherein component (2) is poly (propylene sebacate).  Specification 763,077 is referred to.ALSO:A lubricating composition (see Group III) comprises a blend of (1) a liquid aliphatic diester of a saturated aliphatic dicarboxylic acid and (2) a polyester, soluble in the diester, and having the formula HO(R2OOCR1COO)nR2OH wherein n is an integer, R1 is a C4-C14 alkylene group and R2 is the residue of a glycol HOR2OH which is a tricyclodecane dimethylol, the relative proportions of components (1) and (2) in the blend being such that the viscosity of the blend at 210 DEG F. is 4-30 centistokes.  The composition may also contain an antioxidant (e.g. phenothiazine) or a crystallization suppressant (e.g. a polymerized alkyl ester of acrylic or methacrylic acid).  In an example, a composition is described consisting of (1) a blend of octyl nonyl sebacate, dioctyl sebacate and dinonyl sebacate, (2) a polyester prepared from sebacic acid, 2,2,4-trimethyl-adipic acid, 2,4,4-trimethyl-adipic acid and a commercial mixture of tricyclodecane dimethylol isomers and (3) phenothiazine. Specification 763,077 is referred to.ALSO:Polyesters of the formula HO(R2OOCR1COO)nR2OH wherein n is an integer, R1 is a C1-C4 alkylene group and R2 is the residue of a glycol HOR2OH which is a tricyclodecane dimethylol, are employed in lubricating compositions (see Group III).  The acid, HOOCR1COOH, from which the polyester is derived may be adipic, pimelic, suberic, azelaic, sebacic or brassylic acid; but an equimolecular mixture of 2,2,4-trimethyladipic acid, 2,4,4-trimethyl-adipic acid and sebacic acid is particularly satisfactory.  In an example, a polyester is prepared from 2,2,4-trimethyl-adipic acid, 2,4,4-trimethyl-adipic acid, sebacic acid and commercial tricyclodecanedimethylol (which is believed to be a mixture of three isomers).  Specification 763,077 is referred to.