Patent GB-824249-A (GB)
Title: Improvements relating to synthetic lubricants
IPC: C07C69/34
Filed: 1955-03-04
Abstract: A lubricating composition, suitable for use in aero gas turbines, comprises (1) a liquid aliphatic diester of a saturated aliphatic dicarboxylic acid, and (2) a polyester of formula ROOCR1COO(R2OOCR1COO)nR wherein R is the residue of an aliphatic monohydric alcohol ROH, R1 is the residue of an aliphatic or aromatic dicarboxylic acid HOOC R1COOH, R2 is the residue of a glycol or polyglycol HOR2OH and n is an integer greater than one.  Ingredient (1) may be dioctyl or dinonyl sebacate, or a mixture of these, or octyl nonyl sebacate.  Ingredient (2) is a polyester prepared by reacting in one or more stages, and in the absence of an esterification catalyst, (a) an aliphatic dicarboxylic acid or the anhydride thereof and/or an aromatic dicarboxylic acid or the anhydride thereof, (b) a glycol or polyglycol and (c) an aliphatic monohydric alcohol, the molecular proportion of (c) being less than the molecular proportion of (a), and the molecular proportion of (b) being greater than half the molecular proportion of (a).  In preparing ingredient (2), 2-ethyl hexyl alcohol may be employed as the monohydric alcohol, phthalic acid (which may be used in the form of phthalic anhydride) and/or sebacic acid may be employed as the dicarboxylic acid, and propylene glycol may be employed as the glycol.  The composition may also contain a polymerized ester of acrylic or methacrylic acid and an antioxidant.  Examples of suitable lubricating compositions are given.ALSO:A polyester which is employed as an ingredient of a lubricating composition (see Group III) has the formula ROOCR1COO(R2OOCR1COO)nR, wherein R is the residue of an aliphatic monohydric alcohol ROH, R1 is the residue of an aliphatic or aromatic dicarboxylic acid HOOCR1COOH, R2 is the residue of a glycol or polyglycol HOR2OH and n is an integer greater than one. The polyester is prepared by reacting in one or more stages, and in the absence of an esterification catalyst, (a) an aliphatic dicarboxylic acid or the anhydride thereof and/or an aromatic dicarboxylic acid or the anhydride thereof, (b) a glycol or polyglycol, and (c) an aliphatic monohydric alcohol, the molecular proportion of (c) being less than the molecular proportion of (a), and the molecular proportion of (b) being greater than half the molecular proportion of (a).  In examples: (1) sebacic acid (2.4 mols.), phthalic anhydride (0.6 mol.), 2-ethylhexyl alcohol (0.9 mol.), and propylene glycol (2.85 mols.), are reacted together; and (2) the same materials in the molar proportions 2.4:0.6:2.1:2.25 are reacted together.ALSO:A lubricating composition, suitable for use in aero gas turbines, comprises (1) a liquid aliphatic diester of a saturated aliphatic dicarboxylic acid, and (2) a polyester of formula ROOCR1COO(R2OOCR1COO)nR wherein R is the residue of an aliphatic monohydric alcohol ROH, R1 is the residue of an aliphatic or aromatic dicarboxylic acid HOOCR1 COOH, R2 is the residue of a glycol or polyglycol HOR2OH and n is an integer greater than one.  Ingredient (1) may be dioctyl or dinonyl sebacate, or a mixture of these, or octyl nonyl sebacate.  Ingredient (2) is a polyester prepared by reacting in one or more stages, and in the absence of an esterification catalyst, (a) an aliphatic dicarboxylic acid or the anhydride thereof and/or an aromatic dicarboxylic acid or the anhydride thereof, (b) a glycol or polyglycol, and (c) an aliphatic monohydric alcohol, the molecular proportion of (c) being less than the molecular proportion of (a), and the molecular proportion of (b) being greater than half the molecular proportion of (a).  In preparing ingredient (2), 2-ethyl hexyl alcohol may be employed as the monohydric alcohol, phthalic acid (which may be used in the form of phthalic anhydride) and/or sebacic acid may be employed as the dicarboxylic acid, and propylene glycol may be employed as the glycol.  The composition may also contain a polymerized ester of acrylic or methacrylic acid and an antioxidant.  Examples of suitable lubricating compositions are given.