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US4182851A
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Process for reducing the residual monomer content in the polymerization of vinyl-lactams and vinyl esters
Assignee: BASF SE
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Filing: 1978-06-27
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Granted: 1980-01-08
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Expires: 1998-06-27
Abstract
Abstract A process for reducing the residual monomer content of a copolymer prepared by copolymerizing vinyl esters and N-vinyl-lactams in a solvent in the presence of a free radical polymerization initiator. Following the main polymerization, from 0.05 to 0.5% by weight, based on the monomers employed, of di-tert.-butyl peroxide, di-tert.-amyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis-(tert.-butylperoxy)-hexane, 2,2-bis-(tert.-butylperoxy)-butane, 1,1-bis-(tert.-butylperoxy)-3,3,5-trimethylcyclohexane, 4,4-di-(tert.-butylperoxy)-butyl valerate, or a mixture of these, is added to the reaction mixture and the after-polymerization is carried out at a higher temperature than the main polymerization.
Inventors
- 👤 Ferdinand Straub
- 👤 Herbert Spoor
- 👤 Hans-Uwe Schenck
- 👤 Wolfgang Schwarz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:34
CPC Classifications
C; C08; C08F; C08F263/00; C08F263/02; C08F271/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
141 words
A process for reducing the residual monomer content in a polymer solution obtained from the copolymerization of vinyl ester and N-vinyl-lactams in a solvent, the copolymer produced containing from 10 to 90% by weight of N-vinyl-lactam and from 90 to 10% by weight of vinyl ester, based on the monomers, which comprises: (a) polymerizing the vinyl esters and N-vinyl-lactams to completion of the polymerization reaction at temperatures of from 45° to 100° C.; (b) adding from 0.05 to 0.5% by weight, based on the monomers employed, of at least one peroxide selected from the group consisting of di-tert.-butyl peroxide, di-tert.-amyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis-(tert.-butylperoxy)-hexane, 2,2-bis-(tert.-butyl peroxy)-butane, 1,1-bis-(tert.-butylperoxy)-3,3,5-trimethylcyclohexane or 4,4-di-(tert.-butylperoxy)-butyl valerate, and then (c) after-polymerizing the mixture obtained from step (b) at temperatures of from 110° to 160° C. to reduce the residual monomer content to a value less than about 0.1%.
Claim 2
Dependent Claim
141 words
A process for reducing the residual monomer content in a polymer solution obtained from the copolymerization of vinyl ester and N-vinyl-lactams in a solvent, the copolymer produced containing from 10 to 90% by weight of N-vinyl-lactam and from 90 to 10% by weight of vinyl ester, based on the monomers, which comprises: (a) polymerizing the vinyl esters and N-vinyl-lactams to completion of the polymerization reaction at temperatures of from 45° to 100° C.; (b) adding from 0.05 to 0.5% by weight, based on the monomers employed, of at least one peroxide selected from the group consisting of di-tert.-butyl peroxide, di-tert.-amyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis-(tert.-butylperoxy)-hexane, 2,2-bis-(tert.-butyl peroxy)-butane, 1,1-bis-(tert.-butylperoxy)-3,3,5-trimethylcyclohexane or 4,4-di-(tert.-butylperoxy)-butyl valerate, and then (c) after-polymerizing the mixture obtained from step (b) at temperatures of from 110° to 160° C. to reduce the residual monomer content to a value less than about 0.1%.
Claim 3
Dependent Claim
35 words
A process as set forth in claim 1, wherein the polymerization of step (a) is carried out under atmospheric pressure and the after-polymerization is carried out under a pressure of from 1 to 50 bars.
Claim 4
Dependent Claim
15 words
A process as set forth in claim 1, wherein N-vinylpyrrolidone is employed as the vinyl-lactam.
Claim 5
Dependent Claim
20 words
A process as set forth in claim 1, wherein the after-polymerization is carried out for from 0.5 to 5 hours.
Claim 6
Dependent Claim
16 words
A process as set forth in claim 3, wherein the vinyl ester employed is vinyl acetate.
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) | 1983-01-07 | 1983-07-09 | 1984-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-07 | 1987-07-09 | 1988-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-07 | 1991-07-09 | 1992-01-08 | $7700.00 | Window Closed / Lapsed |