Claims
- 1. A lubricating composition comprising a base mineral oil and a viscosity index improving amount of a viscosity index improver comprising a block copolymer having two or three block segments, having a molecular weight ranging from about 12,000 to 500,000 and having an Mw/Mn ratio less than 2, which comprises (a) from about 5 to 50 wt.% in blocks of styrene or alpha-methylstyrene, and (b) from about 50 to 95 wt.% in blocks of 3,4-dimethyl-alpha-methylstyrene.
- 2. the lubricating composition of claim 1 wherein the block copolymer has a molecular weight ranging from about 100,000 to 300,000.
- 3. The lubricating composition of claim 1 wherein the block copolymer contains from about 10 to 30 wt. % in blocks of styrene or alpha-methylstyrene.
- 4. The lubricating composition of claim 1 wherein the block copolymer has a Mw/Mn ratio less than 1.5.
- 5. The lubricating composition of claim 1 wherein the effective amount of viscosity index improver ranges from about 0.5 to 5 wt. %.
- 6. The lubricating composition of claim 5 wherein the viscosity index improver commprises a block copolymer having three block segments having a molecular weight ranging from about 100,000 to 300,000 and having a Mw/Mn ratio less than 1.5, which comprises from about 10 to 30 wt. % in outer blocks of styrene and (b) from about 70 to 90 wt. % in an inner block of 3,4-dimethyl-alpha-methylstyrene.
- 7. The lubricating composition of claim 6 wherein the block copolymer has a molecular weight of about 200,000 and which contains about 12 wt. % styrene.
- 8. A method for improving the viscosity index of a lubricating composition comprising a base mineral oil, comprising adding to the composition an effective amount ranging from about 0.1 to 10 wt.% of a block copolymer having two or three block segments, having a molecular weight ranging from about 10,000 to 500,000 and having an Mw/Mn ratio less than 2, which comprises (a) from about 5 to 50 wt.% in blocks of styrene or alpha-methylstyrene, and (b) from about 50 to 95 wt.% in blocks of 3,4-dimethyl-alpha-methylstyrene, such that the viscosity index of the composition is improved.
- 9. The method of claim 8 wherein the viscosity index improver comprises a block copolymer having three block segments having a molecular weight ranging from about 100,000 to 300,000 and having a Mw/Mn ratio less than 1.5, which contains from about 10 to 30 wt. % in styrene or alpha-methylstyrene.
- 10. The method of claim 9 wherein the block copolymer contains outer blocks of styrene and an inner block of 3,4-dimethyl-alpha-methylstyrene.
- 11. A block copolymer having a molecular weight ranging from about 10,000 to 500,000 and having a Mw/Mn ratio less than 2.0, which comprises (a) from about 5 to 50 wt. % in blocks of styrene or alpha-methylstyrene and (b) from about 50 to 95% in blocks of 3,4-dimethyl-alpha-methylstyrene.
- 12. The block copolymer of claim 11 having three block segments which contains outer blocks of styrene and an inner block of 3,4-dimethyl-alpha-methylstyrene.
- 13. A lubricating composition comprising a base mineral oil and a viscosity index improving amount of a viscosity index improver comprising a block copolymer having two or three block segments having a molecular weight ranging from about 10,000 to 500,000 and having an Mw/Mn ratio less than 2, which comprises (a) from about 5 to 50 wt.% in blocks of styrene or alpha-methylstyrene and (b) from about 50 to 95 wt.% in blocks of lauryl methacrylate.
- 14. The lubricating composition of claim 13 wherein the viscosity index improver comprises a block copolymer having a molecular weight ranging from about 10,000 to 300,000 and having an Mw/Mn ratio less than 1.5, which comprises (a) from about 10 to 30 wt.% in an inner block block of styrene and (b) from about 70 to 90 wt.% in outer blocks of lauryl methacrylate.
- 15. The lubricating composition of claim 13 wherein the block copolymer has a molecular weight of about 200,000.
- 16. A method for improving the viscosity index of a lubricating composition comprising a base mineral oil comprising adding to the composition an effective amount ranging from about 0.1 to 10 wt. % of a block copolymer having two or three block segments, having a molecular weight ranging from about 10,000 to 500,000 and having an Mw/Mn ratio less than 2, which comprises (a) from about 5 to 50 wt.% in blocks of styrene or alpha-methylstyrene, and (b) from about 50 to 95 wt.% in blocks of lauryl methacrylate, such that the viscosity index of the composition is improved.
- 17. The method of claim 16 wherein the block copolymer contains an inner block of styrene and outer blocks of lauryl methacrylate.
- 18. A block copolymer having two or three block segments, having a molecular weight ranging from about 10,000 to 500,000 and having an Mw/Mn ratio less than 2.0, which comprises (a) from about 5 to 50 wt.% in blocks of styrene or alpha-methylstyrene and (b) from about 50 to 95 wt. % in blocks of lauryl methacrylate.
- 19. The block copolymer of claim 18 having three block segments which contain an inner block of styrene and outer blocks of lauryl methacrylate.
Parent Case Info
This is a continuation of application Ser. No. 615,606, filed Sept. 22, 1975, now abandoned.
US Referenced Citations (9)
Continuations (1)
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Number |
Date |
Country |
Parent |
615606 |
Sep 1975 |
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