US4179384A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stabilized hydraulic fluid
Assignee: Gulf Research and Development Co
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Filing: 1978-11-09
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Granted: 1979-12-18
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Expires: 1998-11-09
Abstract
Abstract Mineral oil or synthetic hydrocarbon base hydraulic fluids containing a zinc bis(dialkyldithiophosphate) as an antiwear agent are stabilized against degradation at elevated operating temperatures by the incorporation in the hydraulic fluid of an appropriate Group I or Group II metal phosphonate. For example, a hydraulic fluid containing a zinc bis(dialkyldithiophosphate) is stabilized by the presence of a minor amount of a sodium phosphonate.
Inventors
- 👤 James T. Mann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:46
CPC Classifications
C; C10; C10M; C10M137/00; C10M2205/00; C10M2205/02; C10M2205/026; C10M2205/028; C10M2223/00; C10M2223/02; C10M2223/04; C10M2223/045; C10M2223/06; C10M2223/065; C10N; C10N2010/00; C10N2010/02; C10N2010/04; C10N2040/00; C10N2040/08
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
143 words
A hydraulic fluid stabilized against thermal degradation comprising a base oil having a 100° F. (37.8° C.) viscosity of between about 100 SUS (20.6 cs.) and about 1,000 SUS (215 cs.) and selected from highly refined mineral oils, alpha-olefin oligomers and mixtures thereof; from about 0.1 to about 2.0 volume percent of one or more zinc bis(dialkyldithiophosphate)s in which the alkyl groups have between about four and about twelve carbon atoms; and from about 0.01 to about one volume percent of an alkali metal or alkaline earth metal phosphonate having the general formula ##STR2## in which M is an alkali metal or alkaline earth metal, n is the valence of the metal, R is lower alkyl having one to about four carbon atoms and R' is higher alkyl having from about 10 to about 30 carbon atoms, or a mixture of said phosphonates.
Claim 2
Dependent Claim
143 words
A hydraulic fluid stabilized against thermal degradation comprising a base oil having a 100° F. (37.8° C.) viscosity of between about 100 SUS (20.6 cs.) and about 1,000 SUS (215 cs.) and selected from highly refined mineral oils, alpha-olefin oligomers and mixtures thereof; from about 0.1 to about 2.0 volume percent of one or more zinc bis(dialkyldithiophosphate)s in which the alkyl groups have between about four and about twelve carbon atoms; and from about 0.01 to about one volume percent of an alkali metal or alkaline earth metal phosphonate having the general formula ##STR2## in which M is an alkali metal or alkaline earth metal, n is the valence of the metal, R is lower alkyl having one to about four carbon atoms and R' is higher alkyl having from about 10 to about 30 carbon atoms, or a mixture of said phosphonates.
Claim 3
Dependent Claim
123 words
A hydraulic fluid stabilized against thermal degradation comprising a base oil having a 100° F. (37.8° C.) viscosity of between about 100 SUS (20.6 cs.) and about 1,000 SUS (215 cs.) and selected from highly refined mineral oils, alpha-olefin oligomers and mixtures thereof; from about 0.1 to about 2.0 volume percent of one of more zinc bis(dialkyldithiophosphate)s in which the alkyl groups have between about four and about twelve carbon atoms; and from about 0.01 to about one volume percent of a sodium phosphonate having the general formula ##STR3## in which R is lower alkyl having between one and about four carbon atoms and R' is higher alkyl having between about 10 and about 30 carbon atoms, or a mixture of said phosphonates.
Claim 4
Dependent Claim
123 words
A hydraulic fluid stabilized against thermal degradation comprising a base oil having a 100° F. (37.8° C.) viscosity of between about 100 SUS (20.6 cs.) and about 1,000 SUS (215 cs.) and selected from highly refined mineral oils, alpha-olefin oligomers and mixtures thereof; from about 0.1 to about 2.0 volume percent of one of more zinc bis(dialkyldithiophosphate)s in which the alkyl groups have between about four and about twelve carbon atoms; and from about 0.01 to about one volume percent of a sodium phosphonate having the general formula ##STR3## in which R is lower alkyl having between one and about four carbon atoms and R' is higher alkyl having between about 10 and about 30 carbon atoms, or a mixture of said phosphonates.
Claim 5
Dependent Claim
33 words
A hydraulic fluid stabilized against thermal degradation in accordance with claims 1 or 2 in which the alkyl groups in the zinc bis(dialkyldithiophosphate) compound have between about seven and about nine carbon atoms.
Claim 6
Dependent Claim
33 words
A hydraulic fluid stabilized against thermal degradation in accordance with claims 1 or 2 in which the higher alkyl group in the said phosphonate is between about 16 and about 20 carbon atoms.
Claim 7
Dependent Claim
30 words
A hydraulic fluid stabilized against thermal degradation in accordance with claims 1 or 2 in which there is between about 0.05 and about 0.5 volume percent of the said phosphonate.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-17 | 1983-06-18 | 1983-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-17 | 1987-06-18 | 1987-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-17 | 1991-06-18 | 1991-12-18 | $7700.00 | Window Closed / Lapsed |