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US4327237A
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Process for preparing viscosity index improvers for lubricating oils by cracking synthetic rubbers in the liquid phase
Assignee: Agip Petroli SpA
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Filing: 1980-06-04
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Granted: 1982-04-27
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Expires: 2000-06-04
Abstract
Abstract A process for preparing viscosity index improvers for lubricating oils consisting of thermally cracking a solution of an olefin copolymer in mineral oil at a temperature of between 250° C. and 350° C. in an inert atmosphere said solution containing free radical scavengers.
Inventors
- 👤 Luigi Imparato
- 👤 Giampaolo Gerbaz
- 👤 Enrico Betta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:21
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/50; C08F2800/00; C08F2800/20; C10; C10M; C10M2203/00; C10M2203/10; C10M2205/00; C10N; C10N2020/00; C10N2020/01
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
64 words
A process for the preparation of viscosity index improvers for lubricating oils, which process comprises thermally cracking, at a temperature of between 250° C. and 350° C., in an inert atmosphere, under vigorous stirring, a solution of a mono-olefin copolymer in mineral oil, said solution containing of from 0.01 to 0.5 weight percent, based on the weight of the solution, of free radical scavengers.
Claim 2
Dependent Claim
64 words
A process for the preparation of viscosity index improvers for lubricating oils, which process comprises thermally cracking, at a temperature of between 250° C. and 350° C., in an inert atmosphere, under vigorous stirring, a solution of a mono-olefin copolymer in mineral oil, said solution containing of from 0.01 to 0.5 weight percent, based on the weight of the solution, of free radical scavengers.
Claim 3
Dependent Claim
21 words
A process as claimed in claim 1, wherein the copolymer has a numerical average molecular weight of between 40,000 and 200,000.
Claim 4
Dependent Claim
23 words
A process as claimed in claim 1, wherein the thermal cracking is carried out for a time of between 15 and 45 minutes.
Claim 5
Dependent Claim
25 words
A process as claimed in claim 1, wherein the free radical scavengers are chosen from the group consisting of aromatic quinone, phenol and amine compounds.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-04-26 | 1985-10-26 | 1986-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-04-26 | 1989-10-26 | 1990-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-04-26 | 1993-10-26 | 1994-04-27 | $7700.00 | Window Closed / Lapsed |