Viscosity index improver and composition containing same
US4877836A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 24, 1988 |
| Grant date | Oct 31, 1989 |
| Priority date | — |
| Expiry date | May 24, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC10N2070/02
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A polymeric blend particularly useful as a VI improver, which polymeric blend comprises a selectively hydrogenated asymmetric radial polymer comprising a plurality of polymeric arms containing hydrogenated conjugated diolefin monomer units and at least one block copolymer arm comprising a single polymeric block containing predominantly monoalkenyl aromatic hydrocarbon monomer units and a single polymeric block containing predominantly hydrogenated conjugated diolefin monomer units and a selectively hydrogenated linear diblock copolymer containing a single polymeric block containing principally monoalkenyl aromatic hydrocarbon monomer units and a single polymeric block containing predominantly hydrogenated conjugated diolefin monomer units. Both polymers in the blend will be selectively hydrogenated so as to convert (saturate) at least 95% of the ethylenic unsaturation initially contained therein. When used as a VI improver, the polymeric blend unexpectedly improves the thickening efficiency over and above the thickening efficiency that would be expected from a consideration of the individual contribution made by each of the polymers separately. The monoalkenyl aromatic hydrocarbon …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.