Patent GB-861965-A (GB)
Title: Improvements relating to synthetic lubricants
IPC: C10M169/00
Filed: 1957-08-16
Abstract: A lubricating composition comprises a blend of a liquid aliphatic diester of a saturated aliphatic dicarboxylic acid, and a polyester, soluble in the diester and having the general formula HO(R2OOCR1COO)nR2OH . . . . I where n is an integer, R1 is a C4-14 alkylene group; and R2 has the formula <FORM:0861965/IV (a)/1> where x is 0 or an integer; y is an integer; x+y does not exceed 5, R6 is methyl or ethyl and R7 is a C1-4 alkyl group, the relative proportions of diester and polyester being such that the blend has a viscosity of 3-30 cs./210 DEG  F.  The preferred diesters have the formula R4OOCR5COOR4 where R5 is a C4-14 alkylene group and the R4's are C4-18 alkyl groups, preferably branched-chain, examples being di-(2-ethylhexyl) sebacate; di-(3 : 5 : 5-trimethylhexyl) sebacate; 2-ethylhexyl (3 : 5 : 5-trimethylhexyl) sebacate; and mixtures of all three.  The polyesters may be prepared by the process described in Specification 861,963 from the diols described in Specification 861,961.  Optional ingredients are phenothiazine and polymerized alkyl esters of acrylic or methacrylic acid.  Specification 763,077 also is referred to.ALSO:A lubricating composition comprises a blend of a liquid aliphatic diester of a saturated aliphatic dicarboxylic acid, and a polyester, soluble in the diester and having the general formula HO(R2OOCR1COO)nR2OH . . . . . I where n is an integer; R is a C4-18 alkyl group (each separate R may be the same or different); R1 is a C4-14 alkylene group; and R2 has the formula <FORM:0861965/III/1> where x is O or an integer; y is an integer; the average value of x+y does not exceed 5, R6 is methyl or ethyl and R7 is a C1-4 alkyl group. the relative proportions of diester and polyester being such that the blend has a viscosity of 3-30 cs./210 DEG  F.  The preferred diesters have the formula R4OOCR5COOR4, where R5 is a C4-14 alkylene group and the R4s are C4-18 alkyl groups, preferably branched-chain, examples being di-(2-ethylhexyl) sebacate; di-(3 : 5 : 5 - trimethylhexyl) sebacate; 2 - ethylhexyl (3 : 5 : 5-trimethylhexyl) sebacate; and mixtures of all three.  Preferred polyesters have a viscosity of 50-20,000 cs./210 DEG  F.; C7-C8 R1 groups, especially octamethylene, 1 : 1 : 3 - trimethyltetramethylene, or 1 : 3 : 3-trimethyltetramethylene; and an average value of x+y in formula II between 1 and 2.  The polyesters (which are described in Specification 861,963) may be prepared by reacting, in one or more stages, 1 molar proportion of one or more acids HOOCR1COOH with at least one, but preferably not more than 2 molar proportions of one or more diols HO(CH2CH2O)xCH2C(R6)(R7) CH2(OCH2CH2)yOH, which may themselves be prepared (as described in Specification 861,961) by reacting not more than 5 moles. of ethylene oxide with one mole. of a diol HOCH2C(R6)(R7)CH2OH.  Suitable acids are adipic, pimelic, suberic, azelaic, brasseylic, sebacic and an equimolar mixture of 2 : 2 : 4- and 2 : 4 : 4-trimethyl adipic acids and sebacic acid.  A suitable diol can be obtained by reacting 4 moles. of neopentyl glycol with 7 moles. of ethylene oxide.  In examples, polyesters are prepared from the above diol and sebacic acid or a trimethyl adipic/sebacic acid mixture and blended with a diester obtained by reacting equimolar amounts of sebacic acid, 2-ethylhexanol, and 3 : 5 : 5-trimethylhexanol plus 1% wt. of phenothiazine.  The blends may also contain a polymerized alkyl ester of an acrylic or methacrylic acid. Specification 763,077 also is referred to.