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US4519932A
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Low temperature hydraulic fluids based on two centistoke synthetic hydrocarbons
Assignee: Cognis Corp
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Filing: 1983-09-16
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Granted: 1985-05-28
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Expires: 2003-09-16
Abstract
Abstract Useful hydraulic fluids having low temperature properties comparable to MIL-H-5606 fluids but exhibiting markedly superior fire resistance due to their higher flash points are obtained by blending a two centistoke synthetic hydrocarbon oil obtained from the oligomerization of alpha-olefins with a mono- or diester and polymethacrylate viscosity index improver. The fluids of this invention typically have -65 DEG F. viscosities less than 3000 centistokes, 210 DEG F. viscosities of 3.45 or above, and flash points above 320 DEG F. and are readily formulated with conventional additives.
Inventors
- 👤 Nicholas E. Schnur
- 👤 Bruce J. Beimesch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:24
CPC Classifications
C; C10; C10M; C10M169/00; C10M169/04; C10M169/041; C10M105/00; C10M105/08; C10M105/32; C10M105/34; C10M105/36; C10M107/00; C10M107/02; C10M107/10; C10M145/00; C10M145/02; C10M145/10; C10M145/12; C10M145/14; C10M2205/00; C10M2205/02; C10M2205/028; C10M2205/0285; C10M2207/00; C10M2207/02; C10M2207/023; C10M2207/024; C10M2207/28; C10M2207/281; C10M2207/2815; C10M2207/282; C10M2207/2825; C10M2207/283; C10M2207/284; C10M2207/2845; C10M2207/285; C10M2207/2855; C10M2207/286; C10M2207/34; C10M2209/00; C10M2209/02; C10M2209/08; C10M2209/084; C10M2215/00; C10M2215/02; C10M2215/06; C10M2215/062; C10M2215/064; C10M2215/065; C10M2219/00; C10M2219/06; C10M2219/062; C10M2219/066; C10M2219/068; C10M2219/08; C10M2219/082; C10M2219/084; C10M2219/10; C10M2219/104; C10M2219/108; C10M2223/00; C10M2223/02; C10M2223/04; C10M2223/041
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
169 words
An improved low temperature, fire resistant hydraulic fluid having a 210° F. viscosity ≧3.45 centistokes, -65° F. viscosity <3000 and flashpoint ≧320° F. comprising (a) 30 to 90 percent by weight of a synthetic hydrocarbon obtained by the oligomerization of a C 6-12 alpha-olefin or alpha-olefin mixture and having a 210° F. viscosity of 1.6 to 2.2 centistokes; (b) 5 to 50 percent by weight of a monoester or diester containing from 13 to 30 carbon atoms and having a 210° F. viscosity of ≧3.5 centistokes and -65° F. viscosity of <8000 centistokes, said monoester derived from a C 6-17 aliphatic monocarboxylic acid and aliphatic branched-chain alcohol having from 8 to 12 carbon atoms and said diester derived from a C 6-9 aliphatic dicarboxylic acid and aliphatic branched-chain alcohol having from 6 to 10 carbon atoms; and (c) 5 to 20 percent by weight of a polymethacrylate viscosity index improver having a weight average molecular weight in the range 40,000 to 65,000 and intrinsic viscosity of 0.040 to 0.065.
Claim 2
Dependent Claim
169 words
An improved low temperature, fire resistant hydraulic fluid having a 210° F. viscosity ≧3.45 centistokes, -65° F. viscosity <3000 and flashpoint ≧320° F. comprising (a) 30 to 90 percent by weight of a synthetic hydrocarbon obtained by the oligomerization of a C 6-12 alpha-olefin or alpha-olefin mixture and having a 210° F. viscosity of 1.6 to 2.2 centistokes; (b) 5 to 50 percent by weight of a monoester or diester containing from 13 to 30 carbon atoms and having a 210° F. viscosity of ≧3.5 centistokes and -65° F. viscosity of <8000 centistokes, said monoester derived from a C 6-17 aliphatic monocarboxylic acid and aliphatic branched-chain alcohol having from 8 to 12 carbon atoms and said diester derived from a C 6-9 aliphatic dicarboxylic acid and aliphatic branched-chain alcohol having from 6 to 10 carbon atoms; and (c) 5 to 20 percent by weight of a polymethacrylate viscosity index improver having a weight average molecular weight in the range 40,000 to 65,000 and intrinsic viscosity of 0.040 to 0.065.
Claim 3
Dependent Claim
33 words
The hydraulic fluid of claim 1 wherein the synthetic hydrocarbon is derived from an alpha-olefin containing at least 75 percent by weight 1-decene and contains less than 10 percent trimer and higher oligomers.
Claim 4
Dependent Claim
37 words
The hydraulic fluid of claim 2 wherein the synthetic hydrocarbon is present in an amount from 40 to 75 percent by weight and the viscosity index improver is present from about 6 to 12 percent by weight.
Claim 5
Dependent Claim
26 words
The hydraulic fluid of claim 3 wherein the ester is di-2-ethylhexyl adipate or di-2-ethylhexyl azelate present in an amount from 20 to 30 percent by weight.
Claim 6
Dependent Claim
26 words
The hydraulic fluid of claim 3 wherein the ester is 2-ethylhexyl pelargonate or isodecyl pelargonate present in an amount from 40 to 50 percent by weight.
Claim 7
Dependent Claim
29 words
The hydraulic fluid of claim 3 wherein the polymethacrylate viscosity index improver has a weight average molecular weight of 45,000 to 60,000 and intrinsic viscosity of 0.045 to 0.060.
Claim 8
Dependent Claim
25 words
The hydraulic fluid of claim 3 which additionally contains 0.5 to 2 weight percent phenolic antioxidant and 0.5 to 2 weight percent organophosphorous antiwear/EP agent.
Claim 9
Dependent Claim
22 words
The hydraulic fluid of claim 7 wherein the phenolic antioxidant is 4,4'-methylenebis(2,6-di-t-butylphenol) or thiodiethylenebis(3,5-di-t-butyl-4-hydroxy)hydrocinnamate and the organophosphorous antiwear/EP agent is tricresyl phosphate.
Claim 10
Dependent Claim
16 words
The hydraulic fluid of claim 8 which additionally contains up to several parts per million dye.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-27 | 1988-11-26 | 1989-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-27 | 1992-11-26 | 1993-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-27 | 1996-11-26 | 1997-05-28 | $7700.00 | Window Closed / Lapsed |