US2872433A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stabilization of polymeric n-vinyl pyrrolidones with sulfurous acid or alkali metal salts thereof
Assignee: GAF Chemicals Corp
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Filing: 1955-12-27
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Granted: 1959-02-03
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Expires: 1975-12-27
Abstract
No abstract record available.
Inventors
- 👤 Samuel A Glickman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:04
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/30
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
67 words
A PROCESS OF STABILIZING A SOLID POLYMERIC N-VINYL PYRROLIDONE AGAINST DISCOLORATION WHICH COMPRISES UNIFORMLY DISPERSING INTO A SOLUTION OF THE SAID PYRROLIDONE, IN A SOLVENT IN WHICH THE SAID PYRROLIDONE IS SOLUBLE, FROM 0.2 TO 1% BY WEIGHT OF A REAGENT SELECTED FROM THE GROUP CONSISTING OF SULPHUR DIOXIDE, SULFUROUS ACID AND ALKALI METAL SALTS OF SULFUROUS ACID, AND RECOVERING THE STABILIZED SOLID POLYMER FROM SAID SOLVENT.
Claim 2
Dependent Claim
67 words
A PROCESS OF STABILIZING A SOLID POLYMERIC N-VINYL PYRROLIDONE AGAINST DISCOLORATION WHICH COMPRISES UNIFORMLY DISPERSING INTO A SOLUTION OF THE SAID PYRROLIDONE, IN A SOLVENT IN WHICH THE SAID PYRROLIDONE IS SOLUBLE, FROM 0.2 TO 1% BY WEIGHT OF A REAGENT SELECTED FROM THE GROUP CONSISTING OF SULPHUR DIOXIDE, SULFUROUS ACID AND ALKALI METAL SALTS OF SULFUROUS ACID, AND RECOVERING THE STABILIZED SOLID POLYMER FROM SAID SOLVENT.
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) | 1962-02-02 | 1962-08-04 | 1963-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1966-02-02 | 1966-08-04 | 1967-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1970-02-02 | 1970-08-04 | 1971-02-03 | $7700.00 | Window Closed / Lapsed |