Phosphate ester base stocks and aircraft hydraulic fluids comprising the same
AssigneesExxonMobil Research and Engineering Company, Chevron U.S.A. Inc.
InventorsMark E. Okazaki, Adrian D'Souza, Shlomo Antika
Life of this patent
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Abstract
Disclosed are phosphate ester base fluids and aircraft hydraulic fluids containing a novel combination of phosphate ester components. The disclosed aircraft hydraulic fluids contain from about 30 to about 45 weight percent, based on the total weight of the fluid, of tri-iso-butyl phosphate; from about 30 to about 45 weight percent, based on the total weight of the fluid, of tri-n-butyl phosphate; from about 10 to about 15 weight percent, based on the total weight of the fluid, of one or more triaryl phosphates; and an effective amount of a viscosity index improver, an acid control additive and an erosion inhibitor.
Claims9
An aircraft hydraulic fluid composition comprising a phosphate ester base stock comprising a mixture of tri-iso-butyl phosphate and tri-n-butyl phosphate and a sufficient amount of one or more triaryl phosphates such that the base stock composition produces no more than 25% elastomer seal swell;
- an effective amount of a viscsoity index improver;
- an effective amount of acid control additive;
- and an effective amount of an erosion inhibitor;
- wherein the amount of tri-iso-butyl phosphate ranges from about 30 to about 45 weight percent based on the total weight of the fluid, and the amount of tri-n-butyl phosphate ranging from about 30 to about 45 weight percent based on the total weight of the fluid.
An aircraft hydraulic fluid composition comprising a phosphate ester base stock comprising from about 4 to about 14 weight percent, based on the total weight of the hydraulic fluid, of one or more triaryl phosphates, the remainder of the base stock comprising a mixture of tri-iso-butyl phosphate and tri-n-butyl phosphate;
- an effective amount of a viscosity index improver;
- an effective amount of acid control additive;
- and an effective amount of an erosion inhibitor;
- wherein the amount of tri-iso-butyl phosphate ranges from about 30 to about 45 weight percent, based on the total weight of the fluid, and the amount of tri-n-butyl phosphate ranging from about 30 to about 45 weight percent based on the total weight of the fluid.
An aircraft hydraulic fluid comprising:
- (a) from about 30 to about 45 weight percent, based on the total weight of the fluid, of tri-iso-butyl phosphate;
- (b) from about 30 to about 45 weight percent, based on the total weight of the fluid, of tri-n-butyl phosphate;
- (c) from about 10 to about 15 weight percent, based on the total weight of the fluid, of one or more triaryl phosphates;
- (d) an effective amount of a viscosity index improver;
- (e) an effective amount of acid control additive;
- and
- (f) an effective amount of an erosion inhibitor.
An aircraft hydraulic fluid comprising:
- (a) from about 30 to about 45 weight percent, based on the total weight of the fluid, of tri-iso-butyl phosphate;
- (b) from about 30 to about 45 weight percent, based on the total weight of the fluid, of tri-n-butyl phosphate;
- (c) from about 12 to about 16 weight percent, based on the total weight of the fluid, of one or more triaryl phosphates;
- (d) from about 4 to 6 weight percent, based on the total weight of the fluid, of a viscosity index improver;
- (e) from about 5 to 6.5 weight percent, based on the total weight of the fluid, of an acid control additive;
- (f) from about 0.05 to about 0.1 weight percent, based on the total weight of the fluid, of an erosion inhibitor;
- (g) from about 0.005 to about 0.5 weight percent, based on the total weight of the fluid, of a rust inhibitor or a mixture of rust inhibitors;
- and
- (h) from about 0.5 to about 2.5 weight percent, based on the total weight of the fluid, of an antioxidant or a mixture of antioxidants.
Dependencies are inferred from the claim text.