Claims
- 1. A method for operating and lubricating hydraulic systems at pressure of about 4000 psi by employing as a hydraulic fluid a phosphate ester functional fluid comprising a major amount of fire resistant phosphate ester base stock and a minor effective amount of additives comprising one or more anti erosion agent(s), one or more acid scavenger(s) and one or more viscosity index improver(s).
- 2. The method of claim 1 wherein the hydraulic system is operating at a pressure of about 5000 psi or higher.
- 3. The method of claim 1 or 2 wherein the phosphate ester hydraulic fluid base oil comprises a mixture of tri alkyl phosphate, di alkyl aryl phosphate, alkyl diaryl phosphate, and triaryl phosphate.
- 4. The method of claim 3 wherein the dialkyl aryl phosphate and alkyl diaryl phosphate are selected from dibutyl phenyl phosphate, butyl diphenyl phosphate, diisobutyl phenyl phosphate, isobutyl diphenyl phosphate.
- 5. The method of claim 1 or 2 wherein the phosphate ester hydraulic fluid base oil comprises tri alkyl phosphate and tri aryl phosphate.
- 6. The method of claim 5 wherein the tri alkyl phosphate is a mixture of tri iso butyl phosphate and tri-n-butyl phosphate.
- 7. The method of claim 6 wherein the tri iso butyl phosphate constitutes about 30 to 80 wt % of the base stock, the tri n-butyl phosphate constitutes about 20 to 60 wt % of the base stock and the tri aryl phosphate constitutes about 3 to 15 wt %/o of the base stock.
- 8. The method of claim 5 wherein the trialkyl phosphate is tri isobutyl phosphate.
- 9. The method of claim 5 wherein the trialkyl phosphate is tri n-butyl phosphate.
- 10. The method of claim 5 wherein the triaryl phosphate is tri (isopropyl phenyl) phosphate, tri (tert-butyl phenyl) phosphate, or a mixture of the two.
- 11. The method of claim 1 or 2 wherein the fluid further contains one or more of an effective amount of a rust inhibitor or mixture of rust inhibitors and an effective amount of an antioxidant or a mixture of antioxidants.
- 12. The method of claim 8 wherein the fluid comprises a major amount of a fire resistant phosphate ester base stock and a mixture of additives comprising
from 2 to 10 wt % active ingredient, based on the total fluid, of a viscosity index improver, from 4 to 10 wt %, based on the total fluid, of an acid control additive, from 0.01 to 0.15 wt %, based on the total fluid, of an erosion inhibitor, from 0 to 1.0 wt %, based on the total fluid, of one or more rust inhibitors, from 0 to 3 wt %, based on the total fluid, of one or more antioxidants.
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional application No. 60/223,221 filed Aug. 4, 2000.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60223221 |
Aug 2000 |
US |
Continuations (1)
|
Number |
Date |
Country |
Parent |
09922088 |
Aug 2001 |
US |
Child |
10634695 |
Aug 2003 |
US |