Functional fluids comprising low-viscosity, low-volatility polyalpha-olefin base stock

Patent metadata

Field	Value
Publication number	US-11180709-B2
Application number	US-201916968750-A
Country	US
Kind code	B2
Filing date	Jan 14, 2019
Priority date	Feb 19, 2018
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

Disclosed are functional fluids such as automotive engine transmission fluids, clutch fluids, gearbox fluids, electric motor fluids, and/or battery packing cooling fluids comprising a low-viscosity, low-volatility Polyalpha-olefin base stock, and processes for lubricating and/or cooling an engine transmission, an electric motor, and/or a battery packing using such functional fluids.

First claim

What is claimed is:

1. A functional fluid for a clutch, a gear box, a transmission and/or an electric motor and/or a battery pack comprising a saturated polyalpha-olefin (“PAO”) first base stock at a concentration thereof in the range from 3 wt % to 98 wt %, based on the total weight of the functional fluid, the first base stock having:
a kinematic viscosity at 100° C. determined pursuant to ASTM D445 (“KV100”) in the range from 3.0 to 3.6 cSt;
a Noack volatility determined pursuant to ASTM D5800 (“NV”) not higher than 12.5%; and
a high-temperature high-shear viscosity determined pursuant to ASTM (“HTHSV”) at 150° C. of no greater than 1.4 centipoise.

2. The functional fluid of claim 1 comprising the first base stock at a concentration thereof in the range from 50 wt % to 98 wt %, based on the total weight of the functional fluid.

3. The functional fluid of claim 1 , wherein the first base stock comprises C28-C32 polyalpha-olefin oligomers at a concentration of no less than 95 wt %, based on the total weight of the first base stock.

4. The functional fluid of claim 3 , wherein the first base stock comprises C30 polyalpha-olefin oligomers at a concentration of no less than 95 wt %, based on the total weight of the first base stock.

5. The functional fluid of claim 1 , wherein the first base stock comprises polyalpha-olefin oligomers having the following formula at a total concentration thereof, based on the total weight of the first base stock. of no less than 80 wt %:

wherein each R is independently an n-butyl, n-hexyl, n-octyl, n-decyl, or n-dodecyl.

6. The functional fluid of claim 1 , wherein the first base stock has a cold-crank-simulator viscosity at −35° C. determined pursuant to ASTM D4683 (“CCSV”) of no higher than 1,000 centipoise.

7. The functional fluid claim 1 , wherein the PAO has a thermal conductivity at 40° C. in the range from 0.11 to 0.16 watt·meter −1 ·K −1 .

8. The functional fluid of claim 1 , further comprising a Group I, II, III, IV, or V second base stock at a concentration in the range from 0 to 97 wt %, based on the total weight of the functional fluid, and one or more additives at a total concentration thereof in the range from 0 to 20 wt %, based on the total weight of the functional fluid.

9. The functional fluid of claim 1 , having a KV 100 in the range from 3.5 to 4.2 cSt, and a Noack Volatility in the range from 10 to 13 wt %.

10. The functional fluid of claim 1 , which is a hybrid vehicle transmission fluid and/or an electric motor cooling fluid and/or a battery pack cooling fluid.

11. The functional fluid of claim 1 , wherein at least a portion of the first base stock is produced by a process selected from:
(i) a first process comprising oligomerizing one or more C6 to C14 alpha-olefin in the presence of a catalyst system comprising a metallocene compound to obtain a first oligomer mixture, separating a first unhydrogenated precursor to the first base stock from the oligomer mixture, followed by hydrogenating the first unhydrogenated precursor; and
(ii) a second process comprising producing a second oligomer of one or more C6 to C14 alpha-olefin in the presence of a catalyst system comprising a metallocene compound, reacting the second oligomer with one or more C6 to C14 alpha-olefin in the presence of a Lewis acid catalyst to obtain a third oligomer mixture, separating a second
unhydrogenated precursor to the first base stock from the third oligomer mixture, followed by hydrogenating the second unhydrogenated precursor.

12. The functional fluid of claim 11 , wherein in process (ii), the second oligomer consists essentially of a dimer of the one or more of the alpha-olefin.

13. The functional fluid of claim 12 , wherein the first base stock is produced from a process (ii) in which the dimer comprises at least 40 wt % of tri-substituted olefin(s), based on the total weight of the dimer.

14. The functional fluid of claim 11 , wherein the first base stock is produced from a monomer consisting essentially of 1-decene.

15. The functional fluid of claim 12 , wherein the first base stock is produced from a process (ii) in which the second unhydrogenated precursor comprises at least 50 wt % of either tetra-substituted olefin(s) or tri-substituted olefins, based on the total weight of the separated precursor.

16. The functional fluid of claim 1 , wherein the PAO has a rotating pressure vessel oxidation test (RPVOT) break time, determined pursuant to ASTM-D-2272, of at least about 70 minutes.

17. The functional fluid of claim 1 , wherein the PAO has a RPVOT break time, determined pursuant to ASTM-D-2272, of at least about 80 minutes.

18. The functional fluid of claim 1 , wherein the first base stock has a pour point determined pursuant to ASTM D5950 of no higher than −69° C.

19. A process for lubricating and/or cooling an engine transmission, a gearbox, a clutch, an electric motor, and/or a battery pack, comprising:
(I) providing a functional fluid comprising a saturated polyalpha-olefin (“PAO”) first base stock at a concentration thereof in the range from 3 wt % to 98 wt %, based on the total weight of the functional fluid, the PAO base stock having:
a kinematic viscosity at 100° C. determined pursuant to ASTM D445 (“KV100”) in the range from 3.0 to 3.6 cSt;
a high-temperature high-shear viscosity determined pursuant to ASTM (“HTHSV”) at 150° C. of no greater than 1.4 centipoise;
a Noack volatility determined pursuant to ASTM D5800 (“NV”) not higher than 12.5%; and
(II) contacting the functional fluid with the engine transmission, the electric motor, and/or the battery pack.

20. The process of claim 19 , wherein step (II) comprises contacting the functional fluid with both the engine transmission and the electric motor in a hybrid vehicle.

21. The process of claim 19 wherein step (I) comprises one or both of the following processes:
(i) oligomerizing one or more C6 to C14 alpha-olefin in the presence of a catalyst system comprising a metallocene compound to obtain a first oligomer mixture, separating a first unhydrogenated precursor to the first base stock from the oligomer mixture, followed by hydrogenating the first unhydrogenated precursor; and
(ii) producing a second oligomer of one or more C6 to C14 alpha-olefin in the presence of a catalyst system comprising a metallocene compound, reacting the second oligomer with one or more C6 to C14 alpha-olefin in the presence of a Lewis acid catalyst to obtain a third oligomer mixture, separating a second unhydrogenated precursor to the first base stock from the third oligomer mixture, followed by hydrogenating the second unhydrogenated precursor.

22. The process of claim 21 , wherein the one or more C6 to C14 alpha-olefin consists essentially of 1-decene.

23. The process of claim 19 , wherein the first base stock comprises C28-C32 polyalpha-olefin oligomers at a concentration of no less than 95 wt %, based on the total weight of the first base stock.

24. The process of claim 19 , wherein the first base stock comprises polyalpha-olefin oligomers having the following formula at a total concentration thereof, based on the total weight of the first base stock, of no less than 80 wt %:

wherein each R is independently an n-hexyl, n-octyl, or n-decyl

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Emett Craig J
• Lotfizadehdehkordi Babak
• Kuzhiyil Najeeb M
• Han Wenning W
• Braun Heinrich R

Classifications

• C10N2040/40

  Generators or electric motors in oil or gas winning field · CPC title

• C10N2040/04

  Oil-bath; Gear-boxes; Automatic transmissions; Traction drives · CPC title

• C10N2040/08

  Hydraulic fluids, e.g. brake-fluids · CPC title

• C10M2205/0285

  used as base material · CPC title

• C10N2030/74

  Noack Volatility · CPC title