US4554312A
Expired / Lapsed
US
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Method of preparing aqueous solutions of polyvinyl-pyrrolidone homopolymer of various molecular weights using a single initiator system consisting essentially of t-Butylperoxypivalate
Assignee: ISP Investments LLC
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Filing: 1985-02-11
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Granted: 1985-11-19
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Expires: 2005-02-11
Abstract
Abstract Vinylpyrrolidone is polymerized using free radical initiator consisting essentially of t-Butylperoxypivalate and preferably in solvent consisting essentially of water, isopropyl alcohol, sec. butyl alcohol or mixtures thereof.
Inventors
- 👤 Eugene S. Barabas
- 👤 James R. Cho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 07:08
CPC Classifications
C; C08; C08F; C08F26/00; C08F26/06; C08F26/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
75 words
Process for making an aqueous solution of polyvinylpyrrolidone homopolymer which comprises: (a) polymerizing N-vinylpyrrolidone monomer in a reaction zone in the presence of free radical initiator consisting essentially of t-Butylperoxypivalate and solvent consisting essentially of water or a mixture of water with isopropyl alcohol or sec. butyl alcohol or both, and (b) removing product from the reaction zone in the form of an aqueous solution containing between about 20 and about 60 wt. % polyvinylpyrrolidone.
Claim 2
Dependent Claim
75 words
Process for making an aqueous solution of polyvinylpyrrolidone homopolymer which comprises: (a) polymerizing N-vinylpyrrolidone monomer in a reaction zone in the presence of free radical initiator consisting essentially of t-Butylperoxypivalate and solvent consisting essentially of water or a mixture of water with isopropyl alcohol or sec. butyl alcohol or both, and (b) removing product from the reaction zone in the form of an aqueous solution containing between about 20 and about 60 wt. % polyvinylpyrrolidone.
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) | 1988-11-18 | 1989-05-20 | 1989-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-11-18 | 1993-05-20 | 1993-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-11-18 | 1997-05-20 | 1997-11-19 | $7700.00 | Window Closed / Lapsed |