Patent US677895A successfully refreshed from Google Patents.
Patent US4013825A successfully refreshed from Google Patents.
US4013825A
Expired / Lapsed
US
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Manufacture of insoluble and only slightly water-swellable polymers of n-vinyl lactams of improved adsorptivity
Assignee: BASF SE
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Filing: 1975-07-03
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Granted: 1977-03-22
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Expires: 1995-07-03
Abstract
Abstract Manufacture of insoluble polyvinyl lactams in the absence of oxygen and in the presence of α- or β-ketocarboxylic acids or esters thereof.
Inventors
- 👤 Walter Denzinger
- 👤 Ernst Hofmann
- 👤 Karl Herrle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 14:33
CPC Classifications
C; C08; C08F; C08F26/00; C08F26/06; A; A23; A23L; A23L2/00; A23L2/70; A23L2/80; B; B01; B01J; B01J20/00; B01J20/22; C12; C12H; C12H1/00; C12H1/02; C12H1/04; C12H1/0416; C12H1/0424
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
137 words
A process for the manufacture of insoluble and only slightly swellable homopolymers of a vinyl lactam or copolymers of two or more vinyl lactams, said vinyl lactam being selected from the group consisting of N-vinyl pyrrolidone, N-vinyl-caprolactam and N-vinyl piperidone in dilute aqueous solution, in which the vinyl lactam or a mixture of the vinyl lactams is polymerized at a pH of at least 6 and at most 10 and with the exclusion of oxygen, wherein the polymerization or copolymerization is initiated by 0.5 to 10% by weight of said monomers of divinyl ethylene urea, and wherein from 0.05 to 2% by weight, based on vinyl lactam of at least one α- or β-ketocarboxylic acid selected from the group consisting of ascorbic acid, ethyl aceto-acetate and pyruvic acid and mixtures thereof is present in the reaction mixture.
Claim 2
Dependent Claim
137 words
A process for the manufacture of insoluble and only slightly swellable homopolymers of a vinyl lactam or copolymers of two or more vinyl lactams, said vinyl lactam being selected from the group consisting of N-vinyl pyrrolidone, N-vinyl-caprolactam and N-vinyl piperidone in dilute aqueous solution, in which the vinyl lactam or a mixture of the vinyl lactams is polymerized at a pH of at least 6 and at most 10 and with the exclusion of oxygen, wherein the polymerization or copolymerization is initiated by 0.5 to 10% by weight of said monomers of divinyl ethylene urea, and wherein from 0.05 to 2% by weight, based on vinyl lactam of at least one α- or β-ketocarboxylic acid selected from the group consisting of ascorbic acid, ethyl aceto-acetate and pyruvic acid and mixtures thereof is present in the reaction mixture.
Claim 3
Dependent Claim
16 words
A process as set forth in claim 1, wherein the vinyl lactam polymerized is vinyl pyrrolidone.
Claim 4
Dependent Claim
19 words
A process as set forth in claim 1, wherein polymerization is carried out at from 50° to 100° C.
References Cited (Backward Citations)
US2544638A
Cited
US2982762A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-21 | 1980-09-20 | 1981-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-21 | 1984-09-20 | 1985-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-21 | 1988-09-20 | 1989-03-22 | $7700.00 | Window Closed / Lapsed |