US4398995A
Expired / Lapsed
US
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Papery product
Assignee: Teijin Ltd
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Filing: 1981-05-20
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Granted: 1983-08-16
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Expires: 2001-05-20
Abstract
Abstract A papery product consisting essentially of a fibrous web, at least part of said web being made of a wholly aromatic polyamide fiber having a readily soluble skin layer and a sparingly soluble or insoluble core layer, and pressure and heat being applied to said web. Said product is excellent in its mechanical and heat-resisting properties.
Inventors
- 👤 Hideharu Sasaki
- 👤 Tsutomu Nakamura
- 👤 Keizo Shimada
- 👤 Yuzo Aito
- 👤 Yutaka Tabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:40
CPC Classifications
D; D21; D21H; D21H13/00; D21H13/10; D21H13/20; D21H13/26; D04; D04H; D04H1/00; D04H1/40; D04H1/54
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
82 words
A papery product consisting essentially of a fibrous web, at least part of said web being made of a wholly aromatic polyamide fiber having a core comprising an aromatic polyamide material extending along the longitudinal axis of said fiber and a sheath, surrounding said core, comprising the same aromatic polyamide material as said core, said core being substantially insoluble and said sheath being substantially soluble in N-methyl-2-pyrrolidone at a temperature of 35° C., pressure and heat having been applied to said web.
Claim 2
Dependent Claim
82 words
A papery product consisting essentially of a fibrous web, at least part of said web being made of a wholly aromatic polyamide fiber having a core comprising an aromatic polyamide material extending along the longitudinal axis of said fiber and a sheath, surrounding said core, comprising the same aromatic polyamide material as said core, said core being substantially insoluble and said sheath being substantially soluble in N-methyl-2-pyrrolidone at a temperature of 35° C., pressure and heat having been applied to said web.
Claim 3
Dependent Claim
18 words
A papery product of claim 1, containing at least 5% by weight of said wholly aromatic polyamide fiber.
Claim 4
Dependent Claim
26 words
A papery product according to claim 1, wherein a pressure of higher than 50 kg/cm 2 and a temperature of 200° to 350° C. are applied.
Claim 5
Dependent Claim
109 words
A papery product of claim 1, wherein said wholly aromatic polyamide comprises: at least one aromatic polyamide containing repeating units of the formula selected from the group consisting of ##STR17## wherein Ar 1 , Ar 2 and Ar 3 are independent, an unsubstituted divalent aromatic radial, a substituted divalent aromatic radical which comprises a single aromatic ring, two or more condensed aromatic rings, two or more aromatic rings linked together, by a single bond, by a bridging atom or radical, and which are oriented either meta or para, and R 1 , R 2 and R 3 respectively are independently hydrogen or alkyl having 1 to 3 carbon atoms.
Claim 6
Dependent Claim
109 words
A papery product as claimed in claim 4, wherein Ar 1 , Ar 2 and Ar 3 in formula (I) and (II) are independently selected from the group consisting of moieties of the formula: ##STR18## wherein R is a member selected from the group consisting of lower alkyl having 1 to 6 carbon atoms, lower alkoxy having 1 to 6 carbon atoms, halogen and nitro, n is zero or an integer of from 1 to 4 and X' is a member selected from the group consisting of ##STR19## wherein Y is a member selected from the group consisting of hydrogen and lower alkyl having 1 to 6 carbon atoms.
Claim 7
Dependent Claim
62 words
A papery product as claimed in claim 4, wherein said Ar 1 , Ar 2 and Ar 3 in the formula (I) and (II) respectively are independently a member selected from p-phenylene, m-phenylene, biphenylene and radicals of the formula: ##STR20## wherein X 2 represents a member selected from ##STR21## wherein Y 2 is hydrogen or alkyl having 1 to 3 carbon atoms.
Claim 8
Dependent Claim
33 words
A papery product as claimed in claim 4, wherein said wholly aromatic polyamide contains repeating units of the formula (II) in which said Ar 2 and Ar 3 are independently m-phenylene or p-phenylene.
Claim 9
Dependent Claim
16 words
A papery product as claimed in claim 7, wherein Ar 2 and Ar 3 are m-phenylene.
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) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |