US4482603A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wholly aromatic polyamide fiber non-woven sheet and processes for producing the same
Assignee: Teijin Ltd
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Filing: 1983-04-18
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Granted: 1984-11-13
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Expires: 2003-04-18
Abstract
Abstract A wholly aromatic polyamide fiber non-woven sheet having satisfactory density, impregnating property, heat resistance, and surface evenness, comprises mutually, randomly entangled fibers consisting essentially of a wholly aromatic polyamide having 85 molar % or more of at least one type of recurring units selected from those of the formulae (I) and (II): ##STR1## The non-woven sheet is characterized in that the wholly aromatic polyamide fibers have portions thereof having a flattened cross-sectional profile; the aromatic polyamide fibers are fuse-bonded to each other at least at portions thereof intersecting each other; and the sheet includes pores connected to each other, and having a size at the peak of pore size distribution, of 13 microns or less determined by means of a mercury porosimeter, and no voids isolated from each other, and has a porosity of from 5% to 40% and an air permeability rate of from 0.1 to 10,000 sec/100 ml.
Inventors
- 👤 Tsugushi Yoshida
- 👤 Hideharu Sasaki
- 👤 Toru Sawaki
- 👤 Keizo Shimada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:56
CPC Classifications
D; D04; D04H; D04H1/00; D04H1/40; D04H1/54; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249978; Y10T428/29; Y10T428/2913; Y10T428/2973; Y10T442/00; Y10T442/60; Y10T442/608; Y10T442/627; Y10T442/635; Y10T442/682; Y10T442/684; Y10T442/688
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
177 words
A wholly aromatic polyamide fiber non-woven sheet consisting essentially of wholly aromatic polyamide fibers randomly entangled with each other and consisting essentially of a wholly aromatic polyamide having 85 molar % or more of at least one type of recurring unit selected from those of the formulae (I) and (II): ##STR8## which non-woven sheet is characterized in that said wholly aromatic polyamide fibers include (A) drawn, heat-treated fibers and (B) at least one type of fibers selected from the group consisting of undrawn, non-heat-treated fibers and partially drawn, non-heat-treated fibers, and have portions thereof having a flattened cross-sectional profile; said aromatic polyamide fibers are fuse-bonded to each other at least at portions thereof intersecting each other; and said sheet includes pores connected to each other and having a size at the peak of pore size distribution, of not larger than 13 microns determined by means of a mercury porosimeter, and no voids isolated from each other, and has a porosity of from 5% to 40% and an air permeability rate of from 0.1 to 10,000 sec/100 ml.
Claim 2
Dependent Claim
177 words
A wholly aromatic polyamide fiber non-woven sheet consisting essentially of wholly aromatic polyamide fibers randomly entangled with each other and consisting essentially of a wholly aromatic polyamide having 85 molar % or more of at least one type of recurring unit selected from those of the formulae (I) and (II): ##STR8## which non-woven sheet is characterized in that said wholly aromatic polyamide fibers include (A) drawn, heat-treated fibers and (B) at least one type of fibers selected from the group consisting of undrawn, non-heat-treated fibers and partially drawn, non-heat-treated fibers, and have portions thereof having a flattened cross-sectional profile; said aromatic polyamide fibers are fuse-bonded to each other at least at portions thereof intersecting each other; and said sheet includes pores connected to each other and having a size at the peak of pore size distribution, of not larger than 13 microns determined by means of a mercury porosimeter, and no voids isolated from each other, and has a porosity of from 5% to 40% and an air permeability rate of from 0.1 to 10,000 sec/100 ml.
Claim 3
Dependent Claim
25 words
The non-woven sheet as claimed in claim 1, wherein said wholly aromatic polyamide has 90 molar % of the recurring units of the formula (I).
Claim 4
Dependent Claim
37 words
The non-woven sheet as claimed in claim 1 wherein said drawn, heat-treated fibers and partially drawn, non-heat-treated fibers have a denier of 5 or less and said undrawn, non-heat-treated fibers have a denier of more than 3.
Claim 5
Dependent Claim
31 words
The non-woven sheet as claimed in claim 1, wherein the content of the sum of said partially drawn, non-heat-treated fibers and said undrawn, non-heat-treated fibers is at least 10% by weight.
Claim 6
Dependent Claim
23 words
The non-woven sheet as claimed in claim 1, wherein said air-permeability rate is in the range of from 1 to 5000 sec/100 ml.
Claim 7
Dependent Claim
23 words
The non-woven sheet as claimed in claim 5, wherein said air-permeability rate is in the range of from 10 to 5000 sec/100 ml.
Claim 8
Dependent Claim
31 words
The non-woven sheet as claimed in claim 1, which sheet allows mercury to penetrate thereinto in an amount of from 0.10 to 0.50 ml/g determined by means of a mercury porosimeter.
Claim 9
Dependent Claim
53 words
The non-woven sheet as claimed in claim 1, which sheet is composed of a core layer consisting essentially of at least one type of fibers selected from the group consisting of said partially drawn, non-heat-treated fibers and said undrawn, non-heat-treated fibers and two surface layers each consisting essentially of said drawn, heat-treated fibers.
Claim 10
Dependent Claim
26 words
The non-woven sheet as claimed in claim 1, which sheet has a surface roughness, in terms of center line average roughness, of 5 microns or less.
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) | 1987-11-13 | 1988-05-14 | 1988-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-13 | 1992-05-14 | 1992-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-13 | 1996-05-14 | 1996-11-13 | $7700.00 | Window Closed / Lapsed |