US4521483A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vinylidene fluoride resin filament and production thereof
Assignee: Kureha Corp
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Filing: 1984-01-25
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Granted: 1985-06-04
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Expires: 2004-01-25
Abstract
Abstract A composite fiber comprises at least a two layer structure of a sheath and a core, each layer comprising a vinylidene fluoride resin, the core portion having an inherent viscosity of 1.10 dl/g and the sheath portion having an apparent viscosity lower than that of the core portion, said composite fiber having a birefringence of at least 36.0×10 -3 . This composite fiber, which has excellent knot strength (as high as 91 kg/mm 2 ), high tensile strength (as high as 103 kg/mm 2 ), excellent luster, and high processability and productivity, is produced by preparing a composite comprising a core portion of a vinylidene fluoride resin having an inherent viscosity of at least 1.10 dl/g and at least one layer of a sheath portion covering over said core portion, which has an apparent viscosity lower than that of the vinylidene fluoride resin of the core, while at least one of the core portion and the sheath portion is in molten state, and then subjecting the composite to at least one-step stretching to a stretching degree of 5.0-fold or more at a temperature which is lower by 5° C. or more but not lower by 30° C. or more than the melting point of the resin of the core.
Inventors
- 👤 Tohru Sasaki
- 👤 Hiroyuki Endoh
- 👤 Seiichi Ohira
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:09
CPC Classifications
D; D01; D01F; D01F8/00; D01F8/04; D01F8/10; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2929; Y10T428/2933; Y10T428/2964; Y10T428/31504; Y10T428/3154
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
62 words
A composite fiber comprising at least a two layer structure of a sheath and a core, each layer comprising a vinylidene fluoride resin, the core portion having an inherent viscosity of at least 1.10 dl/g and the sheath portion having an apparent viscosity lower than that of the core portion, said composite fiber having an birefringence of at least 36.0×10 -3 .
Claim 2
Dependent Claim
62 words
A composite fiber comprising at least a two layer structure of a sheath and a core, each layer comprising a vinylidene fluoride resin, the core portion having an inherent viscosity of at least 1.10 dl/g and the sheath portion having an apparent viscosity lower than that of the core portion, said composite fiber having an birefringence of at least 36.0×10 -3 .
Claim 3
Dependent Claim
36 words
A composite fiber according to claim 1, wherein the difference in apparent viscosity between the sheath portion and the core portion is at least 4,000 poise measured at 260° C. and a shearing rate of 100/sec.
Claim 4
Dependent Claim
36 words
A composite fiber according to claim 1, wherein the difference in apparent viscosity between the sheath portion and the core portion is at least 6,000 poise measured at 260° C. and a shearing rate of 100/sec.
Claim 5
Dependent Claim
60 words
A composite fiber according to claim 1, wherein the vinylidene fluoride resin is a member selected from the group consisting of vinylidene fluoride homopolymers, copolymers each containing at least 70 mole % of vinylidene fluoride units, and compositions each containing any of these as the main component with a content of vinylidene fluoride units of at least 70 mole %.
Claim 6
Dependent Claim
60 words
A composite fiber according to claim 4, wherein the vinylidene fluoride resin is a member selected from the group consisting of vinylidene fluoride homopolymers, copolymers each containing at least 90 mole % of vinylidene fluoride units, and compositions each containing any of these as the main component with a content of vinylidene fluoride units of at least 90 mole %.
Claim 7
Dependent Claim
38 words
A composite fiber according to claim 4, wherein the vinylidene fluoride resin is a member selected from the group consisting of vinylidene fluoride homopolymers, and compositions each containing at least 95 mole % of a vinylidene fluoride homopolymer.
Claim 8
Dependent Claim
45 words
A composite fiber according to claim 1, wherein the apparent viscosity of the sheath portion is lower than that of the core portion due to an inherent viscosity of the resin of the sheath portion lower than that of the resin of the core portion.
Claim 9
Dependent Claim
41 words
A composite fiber according to claim 1, wherein the apparent viscosity of the sheath portion is lower than that of the core portion due to the presence of a softening agent incorporated only or in greater amount in the sheath portion.
Claim 10
Dependent Claim
14 words
A composite fiber according to claim 8, wherein the softening agent is a plasticizer.
Claim 11
Dependent Claim
15 words
A composite fiber according to claim 8, wherein the softening agent is a softening material.
Claim 12
Dependent Claim
35 words
A composite fiber according to claim 8, wherein the softening agent is a resin which is compatible with the vinylidene fluoride resin employed and has a lower glass transition temperature than said vinylidene fluoride resin.
Claim 13
Dependent Claim
20 words
A composite fiber according to claim 1, wherein the core portion has an inherent viscosity of at least 1.20 dl/g.
Claim 14
Dependent Claim
16 words
A composite fiber according to claim 1, having a birefringence of at least 37×10 -3 .
Claim 15
Dependent Claim
16 words
A composite fiber according to claim 13, having a birefringence of at least 38×10 -3 .
Claim 16
Dependent Claim
20 words
A composite fiber according to claim 1, having a refractive index on the surface thereof of 1.415 as a maximum.
Claim 17
Dependent Claim
20 words
A composite fiber according to claim 15, having a refractive index on the surface thereof of 1.410 as a maximum.
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) | 1988-06-03 | 1988-12-03 | 1989-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-03 | 1992-12-03 | 1993-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-03 | 1996-12-03 | 1997-06-04 | $7700.00 | Window Closed / Lapsed |