US4332765A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for spinning hydrophilic acrylic fibres of low density
Assignee: Bayer AG
•
Filing: 1979-10-09
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Granted: 1982-06-01
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Expires: 1999-10-09
Abstract
Abstract The invention relates to dry-spun hydrophilic core-jacket filaments or fibres of a hydrophobic filament forming synthetic polymer. The filaments or fibres having a porosity of at least 50%, a water-retention capacity of at least 100% and a mercury density of at most 0.7 g/cm 3 . The invention also relates to a process for the production of these fibres and filaments.
Inventors
- 👤 Ulrich Reinehr
- 👤 Toni Herbertz
- 👤 Hermann-Josef Jungverdorben
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:55
CPC Classifications
D; D01; D01D; D01D5/00; D01D5/24; D01D5/247; D01F; D01F6/00; D01F6/44; D01F6/54; D01F8/00; D01F8/04; D01F8/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
147 words
A process for the production of hydrophilic core-jacket low-density filaments or fibres of polyacrylonitrile having a porousity of at least 50%, water retention capacity of at least 100%, and a mercury density of at most 0.7 g/cm 3 of a hydrophilic, filament-forming synthetic polyacrylonitrile which comprises dry spinning the polymer, there being added to the spinning solvent a substance which: (a) has a higher boiling point than the spinning solvent used, (b) is readily miscible with the spinning solvent and with water, and (c) is a non-solvent for the polymer to be spun, the ratio by weight of polymer solids to non-solvent amounts to at most 2:1; and, immediately after the filaments leave the spinning jet or at the latest at a time at which they have still not completely hardened, bringing the filaments into contact at a duct temperature of at most 140° C. with steam.
Claim 2
Dependent Claim
147 words
A process for the production of hydrophilic core-jacket low-density filaments or fibres of polyacrylonitrile having a porousity of at least 50%, water retention capacity of at least 100%, and a mercury density of at most 0.7 g/cm 3 of a hydrophilic, filament-forming synthetic polyacrylonitrile which comprises dry spinning the polymer, there being added to the spinning solvent a substance which: (a) has a higher boiling point than the spinning solvent used, (b) is readily miscible with the spinning solvent and with water, and (c) is a non-solvent for the polymer to be spun, the ratio by weight of polymer solids to non-solvent amounts to at most 2:1; and, immediately after the filaments leave the spinning jet or at the latest at a time at which they have still not completely hardened, bringing the filaments into contact at a duct temperature of at most 140° C. with steam.
Claim 3
Dependent Claim
22 words
The process of claim 1, wherein the steam is blown into the spinning duct in the spinning direction above the spinning jet.
Claim 4
Dependent Claim
15 words
A process according to claim 1, wherein the duct temperature is 105° to 125° C.
References Cited (Backward Citations)
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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) | 1985-05-31 | 1985-11-30 | 1986-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-31 | 1989-11-30 | 1990-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-31 | 1993-11-30 | 1994-06-01 | $7700.00 | Window Closed / Lapsed |