US4264676A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing superfine ion-exchange fibers
Assignee: Nitivy Co Ltd
•
Filing: 1979-08-16
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Granted: 1981-04-28
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Expires: 1999-08-16
Abstract
Abstract Superfine fibers of polyvinyl alcohol type having a single fiber diameter of 0.1-1.0μ and a fineness of 0.8-80×10 -4 d/f are baked in the presence of a dehydration catalyst so that the weight loss ratio of fibers falls under the range of about 5 to 40%. When ion-exchange radicals are introduced into the partially dehydrated fiber, superfine fibers with a high ion-exchange rate are obtained.
Inventors
- 👤 Mitsutaka Uzumaki
- 👤 Masahiko Takashio
- 👤 Akihisa Shirasaka
- 👤 Tadayoshi Utsumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:27
CPC Classifications
B; B01; B01J; B01J47/00; B01J47/12; B01J47/127; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/298
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
70 words
A process for preparing superfine fibers with ion-exchange capacity which comprises baking superfine fibers of a polyvinyl alcohol type having a single fiber diameter of 0.1-1.0μ and a fineness of 0.8-80×10 -4 d/f in the presence of a dehydration catalyst at temperatures of about 80°-350° C. so that a weight loss ratio of fibers falls within the range of about 5-40% and introducing an ion-exchange radical into the baked fibers.
Claim 2
Dependent Claim
70 words
A process for preparing superfine fibers with ion-exchange capacity which comprises baking superfine fibers of a polyvinyl alcohol type having a single fiber diameter of 0.1-1.0μ and a fineness of 0.8-80×10 -4 d/f in the presence of a dehydration catalyst at temperatures of about 80°-350° C. so that a weight loss ratio of fibers falls within the range of about 5-40% and introducing an ion-exchange radical into the baked fibers.
Claim 3
Dependent Claim
20 words
The process of claim 1 wherein the dehydration catalyst is ammonium polyphosphate, phosphoric acid, ammonium phosphate salts and hydrogen chloride.
Claim 4
Dependent Claim
34 words
The process of claim 1 wherein said baking is effected in air, in an atmosphere of an inert gas or in a vacuum under the condition of having the dehydration catalyst involved in fibers.
Claim 5
Dependent Claim
28 words
The process of claim 1 wherein said baking is effected in an atmosphere of a gaseous hydrogen chloride or gaseous mixture of hydrogen chloride with an inert gas.
Claim 6
Dependent Claim
38 words
The process of claim 1 wherein said weight loss ratio of fibers falls within the range of about 5-25% and sulfuric ester radicals are introduced by a sulfation reaction with hydroxyl groups of the remaining vinyl alcohol units.
Claim 7
Dependent Claim
25 words
The process of claim 1 wherein said weight loss ratio of fibers falls within the range of about 20-40% and sulfonic acid radicals are introduced.
Claim 8
Dependent Claim
29 words
Superfine fibers of a polyvinyl alcohol type having a single fiber diameter of 0.1-1.0μ and a fineness of 0.8-80×10 -4 d/f, prepared according to the process of claim 1.
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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) | 1984-04-27 | 1984-10-27 | 1985-04-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-04-27 | 1988-10-27 | 1989-04-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-04-27 | 1992-10-27 | 1993-04-28 | $7700.00 | Window Closed / Lapsed |