Claims
- 1. A lubricating oil composition comprising a lubricating oil and 0.2 to 2.0% by weight of an oil-soluble, liquid, mixed zinc and copper dihydrocarbyl dithiophosphate, wherein the hydrocarbyl groups are alkyl of up to six carbon atoms and the mixed dithiophosphate is prepared by a process in which dihydrocarbyl dithiophosphoric acid is reacted with a mixture of a basic zinc compound and a basic copper compound selected from the group consisting of copper oxide and copper hydroxide.
- 2. A lubricating oil composition as claimed in claim 1 wherein the weight ratio of zinc to copper is from 10:1 to 1:1.
- 3. A lubricating oil composition as claimed in claim 2 wherein the dihydrocarbyl dithiophosphoric acid is derived from a phosphorus pentasulfide having 27.9.+-.0.1 weight % of phosphorus.
- 4. A lubricating oil composition as claimed in claim 2 wherein the dihydrocarbyl groups of the mixed zinc and copper dihydrocarbyl dithiophosphate are 2-ethylhexyl groups.
- 5. A lubricating oil composition as claimed in claim 2 wherein the dihydrocarbyl groups of the mixed zinc and copper dihydrocarbyl dithiophosphate comprise an iso-butyl and an iso-amyl group.
- 6. A concentrate comprising a solvent and from 20 to 90% by weight of an oil-soluble, liquid, mixed zinc and copper dihydrocarbyl dithiophosphate, wherein the hydrocarbyl groups are alkyl of up to six carbon atoms and the mixed dithiophosphate is prepared by a process in which dihydrocarbyl dithiophosphoric acid is reacted with a mixture of a basic zinc compound and a basic copper compound selected from the group consisting of copper oxide and copper hydroxide.
- 7. A concentrate as claimed in claim 6 wherein the weight ratio of zinc to copper is from 10:1 to 1:1.
- 8. A concentrate as claimed in claim 7 wherein the dihydrocarbyl dithiophosphoric acid is derived from a phosphorus pentasulfide having 27.9.+-.0.1 weight % of phosphorus.
- 9. A concentrate as claimed in claim 6 wherein the dehydrocarbyl groups of the mixed zinc and copper dehydrocarbyl dithiophosphate are 2-ethylhexyl groups.
- 10. A concentrate as claimed in claim 7 wherein the dihydrocarbyl groups of the mixed zinc and copper dihydrocarbyl dithiophosphate comprise an iso-butyl and an iso-amyl group.
- 11. A process of providing improved antioxidant and copper corrosion inhibition to a lubricating oil composition comprising adding to a lubricating oil from 0.2 to 2.0% by weight of an oil-soluble, liquid, mixed zinc and copper dihydrocarbyl dithiophosphate, wherein the hydrocarbyl groups are alkyl of up to six carbon atoms and the mixed dithiophosphate is prepared by a process in which dihydrocarbyl dithiophosphoric acid is reacted with a mixture of a basic zinc compound and a basic copper compound selected from the group consisting of copper oxide and copper hydroxide.
- 12. A process a claimed in claim 11 wherein the weight ratio of zinc to copper is from 10.1 to 1:1.
- 13. A process as claimed in claim 11 wherein the dihydrocarbyl dithiophosphoric acid is derived from a phosphorus pentasulfide having 27.9.+-.0.1 weight % of phosphorus.
- 14. A process as claimed in claim 12 wherein the dihydrocarbyl groups of the mixed zinc and copper dihydrocarbyl dithiophosphate are 2-ethylhexyl groups.
- 15. A process as claimed in claim 12 wherein the dihydrocarbyl groups of the mixed zinc and copper dehydrocarbyl dithiophosphate comprise an iso-butyl and an iso-amyl group.
Parent Case Info
This is a divisional, of application Ser. No. 07/938,305, filed Aug. 28, 1992, which is a continuation of application Ser. No. 07/274,819 filed Nov. 22, 1988, now abandoned.
US Referenced Citations (25)
Foreign Referenced Citations (3)
Number |
Date |
Country |
0024146 |
Aug 1980 |
EPX |
0131400 |
Jun 1984 |
EPX |
2056482 |
Aug 1979 |
GBX |
Divisions (1)
|
Number |
Date |
Country |
Parent |
938305 |
Aug 1992 |
|
Continuations (1)
|
Number |
Date |
Country |
Parent |
274819 |
Nov 1988 |
|