US4433112A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of a polyvinylpyrrolidone by heat treatment of an aqueous solution of a conventional polyvinylpyrrolidone
Assignee: BASF SE
•
Filing: 1982-03-15
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Granted: 1984-02-21
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Expires: 2002-03-15
Abstract
Abstract A process for the preparation of high-viscosity polyvinylpyrrolidone, wherein an aqueous polyvinylpyrrolidone solution is subjected to a heat treatment in the presence of a water-insoluble peroxide and in the absence of oxygen, and thickeners containing the polyvinylpyrrolidone thus prepared.
Inventors
- 👤 Ferdinand Straub
- 👤 Heinrich Hartmann
- 👤 Paul Naegele
- 👤 Karl Seib
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:12
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/02; C08J3/03; C08J3/05; C08F; C08F8/00; C08J2339/00; C08J2339/04; C08J2339/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
87 words
Polyvinylpyrrolidone which is characterized by a viscosity of from 1,000 to 2,000 mPa.S at room temperature when admixed in water at a concentration of 2 percent by weight; said polyvinylpyrrolidone obtained by a process comprising: admixing an aqueous solution of polyvinylpyrrolidone of between 5 and 30% by weight obtained by free-radical polymerization, with a water-insoluble organic peroxide of between 0.5 and 5% by weight of polyvinylpyrrolidone; and heating said mixture in the absence of oxygen at between 20° to 250° C. for a sufficient period of time.
Claim 2
Dependent Claim
87 words
Polyvinylpyrrolidone which is characterized by a viscosity of from 1,000 to 2,000 mPa.S at room temperature when admixed in water at a concentration of 2 percent by weight; said polyvinylpyrrolidone obtained by a process comprising: admixing an aqueous solution of polyvinylpyrrolidone of between 5 and 30% by weight obtained by free-radical polymerization, with a water-insoluble organic peroxide of between 0.5 and 5% by weight of polyvinylpyrrolidone; and heating said mixture in the absence of oxygen at between 20° to 250° C. for a sufficient period of time.
Claim 3
Dependent Claim
86 words
Polyvinylpyrrolidone which is characterized by a viscosity of greater than 2,000 mPa.S at room temperature when admixed in water at a concentration of 2 percent by weight; said polyvinylpyrrolidone obtained by a process comprising: admixing an aqueous solution of polyvinylpyrrolidone of between 5 and 30% by weight obtained by free-radical polymerization, with a water-insoluble organic peroxide of between 0.5 and 5% by weight of polyvinylpyrrolidone; and heating said mixture in the absence of oxygen at between 20° to 250° C. for a sufficient period of time.
Claim 4
Dependent Claim
86 words
Polyvinylpyrrolidone which is characterized by a viscosity of greater than 2,000 mPa.S at room temperature when admixed in water at a concentration of 2 percent by weight; said polyvinylpyrrolidone obtained by a process comprising: admixing an aqueous solution of polyvinylpyrrolidone of between 5 and 30% by weight obtained by free-radical polymerization, with a water-insoluble organic peroxide of between 0.5 and 5% by weight of polyvinylpyrrolidone; and heating said mixture in the absence of oxygen at between 20° to 250° C. for a sufficient period of time.
Claim 5
Dependent Claim
13 words
The polyvinylpyrrolidone of claim 2, wherein the viscosity is less than 3,000 mPa.S.
References Cited (Backward Citations)
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US3862915A
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US4053696A
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US4058655A
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US4190718A
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US4254239A
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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) | 1987-02-20 | 1987-08-22 | 1988-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-20 | 1991-08-22 | 1992-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-20 | 1995-08-22 | 1996-02-21 | $7700.00 | Window Closed / Lapsed |