Lubricant compositions

• US 10,066,183 B2
• Filed: 09/08/2016
• Issued: 09/04/2018
• Est. Priority Date: 09/09/2015
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Aswath, Pranesh B., Bagi, Sujay, Shah, Ami, Shah, Kush, Mordaunt, Kane
• Primary Examiner(s): VASISTH, VISHAL V
• Application Number:
  US15/259,608
• Publication Number:
  US 20170066990A1
• Time in Patent Office: 726 Days
• Field of Search: 508197
• CPC Class Codes: C10M 125/22 Compounds containing sulfur, selenium or tellurium
• CPC Class Codes: C10M 139/06 having a metal-to-carbon bond metal complexes of unknown constitution C10M159/18
• CPC Class Codes: C10M 147/02 Monomer containing carbon, hydrogen and halogen only
• CPC Class Codes: C10M 2201/065 Sulfides; Selenides; Tellurides
• CPC Class Codes: C10M 2201/066 Molybdenum sulfide
• CPC Class Codes: C10M 2205/0285 used as base material
• CPC Class Codes: C10M 2207/1285 used as thickening agents
• CPC Class Codes: C10M 2207/129 having hydrocarbon chains of thirty or more carbon atoms
• CPC Class Codes: C10M 2207/289 containing free hydroxy groups
• CPC Class Codes: C10M 2213/062 Polytetrafluoroethylene [PTFE]
• CPC Class Codes: C10M 2219/06 Thio-acids; Thiocyanates; Derivatives thereof
• CPC Class Codes: C10M 2219/068 Thiocarbamate metal salts
• CPC Class Codes: C10M 2223/045 Metal containing thio derivatives
• CPC Class Codes: C10N 2010/02 Groups 1 or 11
• CPC Class Codes: C10N 2010/04 Groups 2 or 12
• CPC Class Codes: C10N 2010/12 Groups 6 or 16
• CPC Class Codes: C10N 2020/02 Viscosity; Viscosity index
• CPC Class Codes: C10N 2020/06 Particles of special shape or size
• CPC Class Codes: C10N 2030/06 Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C10N 2050/10 Semi-solids; greasy
• CPC Class Codes: C10N 2070/00 : Specific manufacturing methods for lubricant compositions

Abstract

In one aspect, lubricant compositions are described herein. In some embodiments, a lubricant composition described herein comprises a grease and milled metal sulfide particles dispersed in the grease. In other cases, a lubricant composition described herein comprises a grease, polytetrafluroethylene particles, zinc dithiophosphate, and molybdenum dialkyldithiocarbamate, wherein the polytetrafluroethylene particles, zinc dithiophosphate, and molybdenum dialkyldithiocarbamate are dispersed in the grease.

Claims

1. A lubricant composition comprising:

a grease; and

milled metal sulfide particles dispersed in the grease,

wherein the milled metal sulfide particles have rounded or dulled or softened edges and an average particle size of 5 to 20 μ

m;

wherein the milled metal sulfide particles are formed from WS₂ or MoS₂; and

wherein the milled metal sulfide particles are present in the lubricant composition in an amount of 1 to 5 weight percent, based on the total weight of the lubricant composition.

2. The lubricant composition of claim 1, wherein the grease is a lithium grease.

3. The lubricant composition of claim 1, wherein the milled metal sulfide particles are formed from WS₂.

4. The lubricant composition of claim 1, wherein the milled metal sulfide particles are formed from MoS₂.

5. The lubricant composition of claim 1, wherein the milled metal sulfide particles form a percolation network within the grease.

6. The lubricant composition of claim 1, wherein the milled metal sulfide particles have rounded edges.

7. The lubricant composition of claim 1, wherein the milled metal sulfide particles have reduced surface energy or reduced asperities compared to non-milled metal sulfide particles.

8. The lubricant composition of claim 1, wherein the lubricant composition provides a reduced average wear scar diameter on lubricated metals compared to a lubricant composition comprising non-milled metal sulfide particles.

9. The lubricant composition of claim 1, wherein the lubricant composition provides a reduced average coefficient of friction on lubricated metals compared to a lubricant composition comprising non-milled metal sulfide particles.

10. The lubricant composition of claim 1 further comprising a dispersant.

11. The lubricant composition of claim 10, wherein the dispersant comprises one or more of a non-ionic surfactant, an anionic surfactant, and a zwitterionic surfactant.

12. The lubricant composition of claim 10, wherein the dispersant comprises sorbitan monooleate or polyisobutylene succinic acid.

13. The lubricant composition of claim 1, wherein the milled metal sulfide particles are surface-functionalized with a polythiol.

14. The lubricant composition of claim 13, wherein the polythiol is present in the lubricant composition in an amount of 1 to 5 weight percent, based on the total weight of the lubricant composition.

15. The lubricant composition of claim 1, wherein:

the grease is a lithium grease; and

the milled metal sulfide particles are surface-functionalized with a polythiol.

18. The lubricant composition of claim 8, wherein the average wear scar diameter on lubricated metals of the lubricant composition is reduced by 5-30% compared to a lubricant composition comprising non-milled metal sulfide particles.

19. The lubricant composition of claim 9, wherein the average coefficient of friction on lubricated metals of the lubricant composition is reduced by 5-35% compared to a lubricant composition comprising non-milled metal sulfide particles.

16. A lubricant composition consisting essentially of milled metal sulfide particles having rounded edges, the milled metal sulfide particles having an average particle size of 5 to 20 μ

m.

17. A method of making a lubricant composition, comprising:

providing metal sulfide particles having an average particle size of 5 to 20 μ

m;

subsequently milling the metal sulfide particles to round the edges of the metal sulfide particles; and

subsequently, after milling, dispersing the milled metal sulfide particles in a grease, wherein the milled metal sulfide particles are formed from WS₂ or MoS₂; and

wherein the milled metal sulfide particles are present in the lubricant composition in an amount of 1 to 5 weight percent, based on the total weight of the lubricant composition.