Patent US4917848A successfully refreshed from Google Patents.
US4917848A
Expired / Lapsed
US
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Process for producing polyester fibers
Assignee: Toyobo Co Ltd
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Filing: 1989-01-10
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Granted: 1990-04-17
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Expires: 2009-01-10
Abstract
Abstract Process for producing polyester fibers of high tenacity and high modulus, by melt-spinning a polyester having an intrinsic viscosity of not lower than 0.3, to obtain extruded filaments of low orientation having a birefringence not higher than 10.0×10 -3 , post-polymerizing the filaments in a heating medium, and subjecting the filaments to multi-stage drawing in at least two stages.
Inventors
- 👤 Kazuo Kurita
- 👤 Youichi Watanabe
- 👤 Susumu Tate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:39
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/80; D; D01; D01F; D01F11/00; D01F11/04; D01F11/08; D01F6/00; D01F6/58; D01F6/62
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
146 words
A process for producing polyester fibers of high tenacity and high modulus, which comprises melt-spinning a polyester having an intrinsic viscosity, measured in a mixed solvent of p-chlorophenol/tetrachlorethane=3/1 at 30° C., of not lower than 0.3, to obtain extruded filaments of low orientation having a birefringence not higher than 10.0×10 -3 , post-polymerizing the filaments in a heating medium at a temperature of 100° to 250° C., and subjecting the post-polymerized filaments to multi-stage drawing at a total draw ratio of more than 6 times in at least two stages, wherein the first stage drawing is at a temperature below the melt-down temperature of the filaments in a swollen state by the heating medium and above 0° C., and the second stage drawing is at a temperature above the drawing temperature of the first stage drawing +20° C. and below the melting point of the polyester.
Claim 2
Dependent Claim
146 words
A process for producing polyester fibers of high tenacity and high modulus, which comprises melt-spinning a polyester having an intrinsic viscosity, measured in a mixed solvent of p-chlorophenol/tetrachlorethane=3/1 at 30° C., of not lower than 0.3, to obtain extruded filaments of low orientation having a birefringence not higher than 10.0×10 -3 , post-polymerizing the filaments in a heating medium at a temperature of 100° to 250° C., and subjecting the post-polymerized filaments to multi-stage drawing at a total draw ratio of more than 6 times in at least two stages, wherein the first stage drawing is at a temperature below the melt-down temperature of the filaments in a swollen state by the heating medium and above 0° C., and the second stage drawing is at a temperature above the drawing temperature of the first stage drawing +20° C. and below the melting point of the polyester.
Claim 3
Dependent Claim
29 words
The process as claimed in claim 1, wherein the heating medium is an aromatic hydrocarbon, an aliphatic hydrocarbon, an alicyclic hydrocarbon or a mixture of two or more thereof.
Claim 4
Dependent Claim
111 words
The process as claimed in claim 1 wherein the heating medium is composed of one or more of the compounds represented by the general formulas (I) and (II): ##STR2## wherein A and A l are each a phenyl group or a cycloalkyl group having 5 to 20 carbon atoms, A 2 to A l-1 are each a phenylene group or a cycloalkylene group having 5 to 20 carbon atoms, R 1 and R 2 are each a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, l is an integer of from 2 to 5, and n and m are each an integer of from 0 to 5.
References Cited (Backward Citations)
US2935372A
Cited
US3840632A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-16 | 1993-10-16 | 1994-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-16 | 1997-10-16 | 1998-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-16 | 2001-10-16 | 2002-04-17 | $7700.00 | Window Closed / Lapsed |