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US4774285A
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Preparation of water-soluble copolymers containing vinylamine units, and their use as wet strength agents and dry strength agents for paper
Assignee: BASF SE
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Filing: 1986-09-15
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Granted: 1988-09-27
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Expires: 2006-09-15
Abstract
Abstract Water-soluble copolymers containing copolymerized vinylamine units are prepared by copolymerizing (a) from 95 to 10 mol % of N-vinylformamide and (b) from 5 to 90 mol % of an ethylenically unsaturated monomer from the group consisting of vinyl acetate, vinyl propionate, C 1 -C 4 -alkyl vinyl ethers, the esters, nitriles and amides of acrylic acid and methacrylic acid and N-vinylpyrrolidone, and then eliminating from 30 to 100 mol % of the formyl groups from the copolymer. Preferred copolymers are copolymers of N-vinylformamide and vinyl acetate, in which from 30 to 100 mol % of the monomer units are hydrolyzed. The copolymers are used in papermaking to increase the dry strength and wet strength of the paper.
Inventors
- 👤 Sigberg Pfohl
- 👤 Michael Kroener
- 👤 Heinrich Hartmann
- 👤 Walter Denzinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:45
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/20; D21H17/33; D21H17/34; D21H17/41; D21H17/44; D21H17/45; C; C08; C08F; C08F226/00; C08F226/02; C08F8/00; C08F8/44; D21H17/36; D21H17/37; C08F2810/00; C08F2810/50; D21H21/00; D21H21/14; D21H21/18
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
102 words
A water-soluble copolymer formed by copolymerizing (a) from 95 to 10 mol% of N-vinylformamide and (b) from 5 to 90 mol% of vinyl acetate and/or vinyl propionate, and then hydrolyzing from 30 to 100 mol% of the formyl groups from the copolymerized units (a) to form amino groups and from 30 to 100 mol% of the acetyl or propionyl groups from the copolymerized units (b) to form hydroxyl groups, and which has a K value of from 50 to 250 (determined by the Fikentscher method in 5% strength by weight aqueous sodium chloride solution at a polymer concentration of 0.5% by weight).
Claim 2
Dependent Claim
102 words
A water-soluble copolymer formed by copolymerizing (a) from 95 to 10 mol% of N-vinylformamide and (b) from 5 to 90 mol% of vinyl acetate and/or vinyl propionate, and then hydrolyzing from 30 to 100 mol% of the formyl groups from the copolymerized units (a) to form amino groups and from 30 to 100 mol% of the acetyl or propionyl groups from the copolymerized units (b) to form hydroxyl groups, and which has a K value of from 50 to 250 (determined by the Fikentscher method in 5% strength by weight aqueous sodium chloride solution at a polymer concentration of 0.5% by weight).
Claim 3
Dependent Claim
32 words
A water-soluble copolymer as claimed in claim 1, wherein from 70 to 95 mol% of the hydrolyzable groups are hydrolyzed from each of the monomer units (a) and (b) of the copolymer.
Claim 4
Dependent Claim
41 words
The water-soluble copolymer of claim 1, wherein said copolymerization is initiated by a free radical polymerization initiator which is at least one member selected from the group consisting of peroxides, redox catalysts, and azo compounds which decompose to give free radicals.
Claim 5
Dependent Claim
14 words
The water-soluble copolymer of claim 3, wherein said free radical polymerization initiator is 2,2-azobis-(2,4-dimethylvaleronitrile).
Claim 6
Dependent Claim
14 words
The water-soluble copolymer of claim 3, wherein said free radical polymerization initiator is 2,2-azobisisobutyronitrile.
Claim 7
Dependent Claim
15 words
The water-soluble copolymer of claim 1, wherein said copolymerization is carried out under atmospheric pressure.
Claim 8
Dependent Claim
15 words
The water-soluble copolymer of claim 1, wherein said copolymerization is carried out under reduced pressure.
Claim 9
Dependent Claim
15 words
The water-soluble copolymer of claim 1, wherein said copolymerization is carried out under superatmospheric pressure.
Claim 10
Dependent Claim
17 words
The water-soluble copolymer of claim 1, wherein said copolymerization is carried out in a solvent or diluent.
Claim 11
Dependent Claim
14 words
The water-soluble copolymer of claim 1, wherein said copolymerization is carried out in water.
Claim 12
Dependent Claim
19 words
The water-soluble copolymer of claim 1, wherein said hydrolysis is carried out by contacting said copolymer with an acid.
Claim 13
Dependent Claim
12 words
The water-soluble copolymer of claim 11, wherein said acid is hydrochloric acid.
Claim 14
Dependent Claim
19 words
The water-soluble copolymer of claim 1, wherein said hydrolysis is carried out by contacting said copolymer with a base.
Claim 15
Dependent Claim
12 words
The water-soluble copolymer of claim 13, wherein said base is sodium hydroxide.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-09-27 | 1992-03-28 | 1992-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-09-27 | 1996-03-28 | 1996-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-09-27 | 2000-03-28 | 2000-09-27 | $7700.00 | Window Closed / Lapsed |