High-viscosity metallocene polyalpha-olefins with high electrohydrodynamic performance

Patent metadata

Field	Value
Publication number	US-10059898-B2
Application number	US-201615166615-A
Country	US
Kind code	B2
Filing date	May 27, 2016
Priority date	Aug 21, 2015
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

A PAO lubricant base stock having a KV100 of at least 200 cSt and comprising multiple PAO molecules comprising at least 200 carbon atoms per molecule, wherein each of the PAO molecules comprises multiple pendant groups; and the average pendant group length of all the pendant groups excluding one methyl on each of the PAO molecules among at least 90 mol % of all of the PAO molecules, if one or more methyl is present, is at least 6.0. The PAO base stock exhibits high EHL thicknesses at 40° C., 80° C., and 120° C., rendering it particularly useful in lubricant compositions experiencing high-stress events such as gear oils, automotive transmission oils, and the like.

First claim

The invention claimed is:

1. A PAO base stock having a kinematic viscosity at 100° C. (“KV100”) of at least 190 cSt and comprising multiple PAO molecules comprising at least 200 carbon atoms per molecule, wherein:
each of the PAO molecules comprising at least 200 carbon molecules per molecule comprises multiple pendant groups;
the average pendant group length of all the pendant groups on each PAO molecule among at least 90 mol % of all of the PAO molecules is at least 6.0, and
the PAO base stock is produced by using a metallocene catalyst from a feed comprising one or more C6-C20 alpha olefins.

2. The PAO base stock of claim 1 having a KV100 of at most 600 cSt.

3. The PAO base stock of claim 1 , wherein at least 90 mol % of all of the PAO molecules contained therein comprise at least 300 carbon atoms per molecule.

4. The PAO base stock of claim 1 , wherein at least 90 mol % of all of the PAO molecules comprise at most 1000 carbon atoms per molecule.

5. The PAO base stock of claim 1 , wherein:
in at least 90 mol % of all of the PAO molecules, at most 5 mol % of the pendant groups are bonded to adjacent carbon atoms on the main carbon chain of the respective PAO molecule.

6. The PAO base stock of claim 1 , wherein:
in at least 90 mol % of all of the PAO molecules, at least 90 mol % of the pendant groups are bonded to carbon atoms on the main carbon chain of the PAO molecule that is separated by only one intermediate carbon atom from the next carbon atom to which a pendant group is attached.

7. The PAO base stock of claim 1 , wherein:
in at least 90 mol % of all of the PAO molecules, there is only one methyl group among all pendant groups in each molecule.

8. The PAO base stock of claim 1 , wherein:
the average pendant group length of all the pendant groups on each of the PAO molecule among at least 90 mol % of all of the PAO molecules is at least 7.0.

9. The PAO base stock of claim 1 , wherein:
in at least 90 mol % of all of the PAO molecules, the mole percentage of mesotriads is at least 90%.

10. The PAO base stock of claim 1 , wherein:
in at least 90 mol % of all of the PAO molecules, at least 50 mol % of the pendant groups attached to an individual PAO molecule have the same length.

11. The PAO base stock of claim 1 , wherein:
in at least 90 mol % of all of the PAO molecules, at least 90 mol % of the pending groups have the same length.

12. The PAO base stock of claim 1 , having a polydispersity of from 1.20 to 2.00.

13. The PAO base stock of claim 1 , having a KV100 in the range from 190 to 400.

14. The PAO base stock of claim 1 , wherein:
the longest 5%, 10%, 20%, 40%, 50%, and 100%, by mole, of the pendant groups of all of the molecules of the PAO base stock have an average pendant group length of Lpg(5%), Lpg(10%), Lpg(20%), Lpg(40%), Lpg(50%), and Lpg(100%), respectively; and at least one of the following conditions is met:
(i) 7.0≤Lpg(5%)≤14.0;
(ii) 7.0≤Lpg(10%)≤14.0;
(iii) 6.5≤Lpg(20%)≤12.0;
(iv) 6.0≤Lpg(40%)≤12.0;
(v) 5.5≤Lpg(50%)≤10.0; and
(vi) 5.0≤Lpg(100%)≤10.0.

15. The PAO base stock of claim 1 , wherein:
at least 90 mol % of all of the PAO molecules comprises from 30 to 70 pendant groups.

16. The PAO base stock of claim 1 , having an EHL film thickness of at least 900 nm at 40° C. at 0.2 m/s.

17. The PAO base stock of claim 1 , having an EHL film thickness of at least 360 nm at 80° C. at 0.2 m/s.

18. The PAO base stock of claim 1 , having an EHL film thickness of at 160 nm at 120° C. at 0.2 m/s.

19. The PAO base stock of claim 1 having a Lpg(M) of at least 6.0, wherein Lpg(M) is the average length of the pendant groups excluding one methyl in at least 90 mol % of the PAO molecules, if one of more methyl is present on the PAO molecule.

20. The PAO base stock of claim 1 having a KV100 of at least 190 cSt and comprising multiple PAO molecules comprising at least 200 carbon atoms per molecule, wherein the PAO molecules comprise structural units derived from C8-C20 alpha olefin monomers and are produced by using a metallocene catalyst.

21. The PAO base stock of claim 20 , wherein each of the multiple PAO molecules has a percentage of (mm)-triads of at least 60 mol % as determined by C 13 -NMR.

22. A lubricant composition comprising a PAO base stock of claim 1 .

23. A lubricant composition of claim 22 , which is a gear box lubricant.

24. A lubricant composition of claim 22 , which is an automobile transmission lubricant.

25. The PAO base stock of claim 1 having a KV100 of at least 200 cSt.

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Han Wenning W

Classifications

• C10N2040/042

  for automatic transmissions · CPC title

• C10N2020/071

  Branched chain compounds · CPC title

• C10M105/04 Primary

  aliphatic · CPC title

• C10N2020/02

  Viscosity; Viscosity index · CPC title

• C10N2030/58

  Elastohydrodynamic lubrication, e.g. for high compressibility layers · CPC title