Patent US2720440A successfully refreshed from Google Patents.
US2720440A
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US
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Bleaching polyacrylonitrile fibers
Assignee: EIDP Inc
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Filing: 1952-12-26
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Granted: 1955-10-11
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Expires: 1972-12-26
Abstract
No abstract record available.
Inventors
- 👤 John G Wallace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:18
CPC Classifications
D; D06; D06L; D06L4/00; D06L4/10; D06L4/15; D06L4/12; D06L4/17; Y; Y10; Y10S; Y10S8/00; Y10S8/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
44 words
THE METHOD OF BLEACHING POLYACRYLONITRILE FIBER COMPRISING SUBJECTING THE FIBER TO THE ACTION OF A BLEACH SOLUTION COMPRISING AN AGENT FROM THE GROUP CONSISTING OF PERFORMIC ACID, HYDROGEN PEROXIDE AND MIXTURES THEREOF, DISSOLVED IN A SOLVENT CONTAINING AT LEAST 75% FORMIC ACID BY WEIGHT.
Claim 2
Independent Claim
44 words
THE METHOD OF BLEACHING POLYACRYLONITRILE FIBER COMPRISING SUBJECTING THE FIBER TO THE ACTION OF A BLEACH SOLUTION COMPRISING AN AGENT FROM THE GROUP CONSISTING OF PERFORMIC ACID, HYDROGEN PEROXIDE AND MIXTURES THEREOF, DISSOLVED IN A SOLVENT CONTAINING AT LEAST 75% FORMIC ACID BY WEIGHT.
References Cited (Backward Citations)
US1075663A
Cited
US2077103A
Cited
US2347434A
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GB581046A
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US2432447A
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US2432448A
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FR918532A
Cited
US2526839A
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US2512640A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1958-10-10 | 1959-04-11 | 1959-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1962-10-10 | 1963-04-11 | 1963-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1966-10-10 | 1967-04-11 | 1967-10-11 | $7700.00 | Window Closed / Lapsed |