LUBRICANT ADDITIVE COMPOSITIONS HAVING IMPROVED VISCOSITY INDEX INCREASE PROPERTIES

• US 20100035774A1
• Filed: 08/06/2009
• Published: 02/11/2010
• Est. Priority Date: 08/08/2008
• Status: Active Grant

• Current Assignee: Afton Chemical Corporation
• Original Assignee: Afton Chemical Corporation
• Inventors: GROWCOTT, Peter
• Granted Patent: US 8,778,857 B2
• Time in Patent Office: Days
• US Class Current: 508/100
• CPC Class Codes: C10M 157/00 Lubricating compositions characterised by the additive being a mixture of two or more macromolecular compounds covered by more than one of the main groups C10M143/00 - C10M155/00, each of these compounds being essential
• CPC Class Codes: C10M 2205/022 Ethene
• CPC Class Codes: C10M 2205/024 Propene
• CPC Class Codes: C10M 2205/026 Butene
• CPC Class Codes: C10M 2205/04 containing aromatic monomers, e.g. styrene
• CPC Class Codes: C10M 2205/06 containing conjugated dienes
• CPC Class Codes: C10M 2205/08 containing non-conjugated dienes
• CPC Class Codes: C10M 2209/084 Acrylate; Methacrylate
• CPC Class Codes: C10N 2020/019 Shear stability
• CPC Class Codes: C10N 2020/04 Molecular weight; Molecular weight distribution
• CPC Class Codes: C10N 2030/02 Pour-point; Viscosity index
• CPC Class Codes: C10N 2030/68 Shear stability
• CPC Class Codes: C10N 2030/74 Noack Volatility
• CPC Class Codes: C10N 2040/25 Internal-combustion engines
• CPC Class Codes: C10N 2070/02 Concentrating of additives

Abstract

A lubricant composition, additive concentrate, and method for lubricating an engine. The crankcase lubricant has less than 30 weight percent of a relatively low Noack volatility base oil and a viscosity additive. The viscosity additive has a minor effective amount of sacrificial polymeric viscosity index improver having a shear stability index (SSI) of greater than about 45 and a major amount of a viscosity index improver having an SSI of less than about 26. The minor amount of sacrificial viscosity index improver additive is effective to provide a lubricant composition having a ratio of absolute viscosity increase at 40° C. to an absolute viscosity increase at 40° C. of an RL 216 reference oil of less than about 0.8.

Claims

1. A lubricant composition comprising less than about 30 weight percent of a relatively low Noack volatility base oil and a viscosity additive comprising a minor effective amount of sacrificial polymeric viscosity index improver having a shear stability index (SSI) of greater than about 45 and a major amount of a viscosity index improver having an SSI of less than about 26, wherein the minor amount of sacrificial viscosity index improver additive is effective to provide a lubricant composition having a ratio of absolute viscosity increase at 40°

C. to an absolute viscosity increase at 40°

C. of an RL 216 reference oil of less than about 0.8.

2. The lubricant composition of claim 1, wherein the lubricant composition further comprises at least one component selected from the group consisting of overbased detergents, antioxidants, dispersants, extreme pressure agents, wear reduction agents, antifoaming agents, friction modifying agents, pour-point depressants, and combinations thereof.

3. The lubricant composition of claim 1, wherein the viscosity index improver having an SSI of less than about 26 comprises an olefin copolymer viscosity index improver derived from ethylene and an olefin having from about 3 to about 23 carbon atoms.

4. The lubricant composition of claim 3, wherein the viscosity additive comprises from about 0.5 to about 3.0 percent by weight of the sacrificial viscosity index improver and from about 5 to about 15 percent by weight of the olefin copolymer viscosity index improver, based on a total weight of the lubricant composition.

5. The lubricant composition of claim 1, wherein the base oil has a Noack volatility ranging from about 7.0 to about 15 wt. %, and wherein the base oil comprises less than 30 wt. % of a base oil selected from the group consisting of a Group III base oil, a Group IV base oil, and a mixture thereof.

6. The lubricant composition of claim 1, wherein the sacrificial viscosity index improver comprises a shear stable, dispersant polyalkyl(meth)acrylate viscosity index improver derived from butylmethacrylate;

lauryl methacrylate;

cetyl methacrylate, and dimethylaminopropyl methacrylamide.

7. The lubricant composition of claim 6 wherein the polymethacrylate viscosity index improver has a number average molecular weight ranging from about 250,000 to about 400,000 daltons.

8. An engine crankcase comprising the lubricant composition of claim 1, wherein the lubricant composition provides an absolute viscosity increase at 40°

C. of less than about 90 mm²/sec.

22. The lubricant composition of claim 1, wherein an amount of the sacrificial polymeric viscosity index improver ranges from about 0.5 to about 3.0 percent by weight based on a total weight of the lubricant composition.

9. A viscosity additive concentrate for a lubricant, comprising a minor amount of a sacrificial polymeric viscosity index improver having a shear stability index (SSI) of greater than about 45 and a major amount of a viscosity index improver having an SSI of less than about 26, wherein a fully formulated lubricant containing the viscosity additive concentrate includes a major amount of base oil having a Noack volatility ranging from about 7.0 to about 15 wt. % and the additive concentrate is effective to provide a lubricant composition having a ratio of absolute viscosity increase at 40°

C. to an absolute viscosity increase at 40°

C. of an RL 216 reference oil of less than about 0.8.

10. A lubricant additive comprising the additive concentrate of claim 9 and further comprising at least one component selected from the group consisting of overbased detergents, antioxidants, detergents, extreme pressure agents, wear reduction agents, antifoaming agents, friction modifying agents, pour-point depressants, and combinations thereof.

11. The additive concentrate of claim 9, wherein the viscosity index improver having an SSI of less than about 26 comprises an olefin copolymer viscosity index improver derived from ethylene and an olefin having from about 3 to about 23 carbon atoms.

12. The additive concentrate of claim 11, comprising from about 2.5 to about 15 percent by weight sacrificial viscosity index improver and from about 25 to about 75 percent by weight olefin copolymer viscosity index improver, based on a total weight of the additive concentrate.

13. The additive concentrate of claim 9, wherein the sacrificial viscosity index improver comprises a shear stable, dispersant polyalkyl(meth)acrylate viscosity index improver derived from butylmethacrylate;

lauryl methacrylate;

cetyl methacrylate, and dimethylaminopropyl methacrylamide.

14. The additive concentrate of claim 13 wherein the polymethacrylate viscosity index improver has a number average molecular weight ranging from about 250,000 to about 400,000 daltons.

23. The additive concentrate of claim 9, comprising from about 2.5 to about wt. % of the sacrificial polymeric viscosity index improver based on a total weight of the additive concentrate.

15. A method for lubricating an engine, comprising providing a lubricant composition of comprising less than about 30 weight percent of a relatively low Noack volatility base oil and a viscosity additive comprising a minor effective amount of sacrificial polymeric viscosity index improver having a shear stability index (SSI) of greater than about 45 and a major amount of a viscosity index improver having an SSI of less than about 26 wherein the minor amount of sacrificial polymeric viscosity index improver additive is effective to provide a lubricant composition having a ratio of absolute viscosity increase at 40°

C. to an absolute viscosity increase at 40°

C. of an RL 216 reference oil of less than about 0.8 to an engine crankcase and operating the engine.

16. The method of claim 15, wherein the viscosity additive comprises from about 0.5 to about 3.0 percent by weight of the sacrificial polymeric viscosity index improver and from about 5 to about 15 percent by weight of the olefin copolymer viscosity index improver, based on a total weight of the lubricant composition.

17. The method of claim 16, wherein the olefin copolymer viscosity index improver comprises a copolymer derived from ethylene and an olefin having from about 3 to about 23 carbon atoms.

18. The method of claim 15, wherein the lubricant composition further comprises at least one component selected from the group consisting of overbased detergents, antioxidants, dispersants, extreme pressure agents, wear reduction agents, antifoaming agents, friction modifying agents, pour-point depressants, and combinations thereof.

19. The method of claim 16, wherein the sacrificial polymeric viscosity index improver comprises a shear stable, dispersant polyalkyl(meth)acrylate viscosity index improver derived from butylmethacrylate;

lauryl methacrylate;

cetyl methacrylate, and dimethylaminopropyl methacrylamide.

20. The method of claim 19, wherein the polymethacrylate viscosity index improver has a number average molecular weight ranging from about 250,000 to about 400,000 daltons.

21. The method of claim 15, wherein the lubricant composition provides an absolute viscosity increase at 400 C. of less than about 90 mm²/sec.