# US 4,398,995 A · Papery product

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- Number: US 4,398,995 A
- Document ID: US4398995A
- Status: Granted
- Kind: A
- Application number: 06/265,583
- Filed: 1981-05-20
- Granted: 1983-08-16
- Earliest claimed: 1980-05-26
- Assignees: Teijin Limited
- Inventors: Hideharu Sasaki; Tsutomu Nakamura; Keizo Shimada; Yuzo Aito; Yutaka Tabe
- Web page: https://patentgrep.com/patent/US4398995A

## CPC

- D21H 13/26: Polyamides; Polyimides
- D04H 1/54: by welding together the fibres, e.g. by partially melting or dissolving (in combination with needling D04H1/485)
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D04H: MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL (weaving D03; knitting D04B; braiding D04C; net-making D04G; sewing D05B; tufting D05C; finishing non-woven fabrics D06); FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING {; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION}(non-woven fabrics having an intermediate or external layer of a different kind, e.g. of woven fabric, B32B)

## 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.

## Claims

### Claim 1

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.degree. C., pressure and heat having been applied to said web.

### Claim 2 (depends on 1)

A papery product of claim 1, containing at least 5% by weight of said wholly aromatic polyamide fiber.

### Claim 3 (depends on 1)

A papery product according to claim 1, wherein a pressure of higher than 50 kg/cm.sup.2 and a temperature of 200.degree. to 350.degree. C. are applied.

### Claim 4 (depends on 1)

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.sub.1, Ar.sub.2 and Ar.sub.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.sub.1, R.sub.2 and R.sub.3 respectively are independently hydrogen or alkyl having 1 to 3 carbon atoms.

### Claim 5 (depends on 4)

A papery product as claimed in claim 4, wherein Ar.sub.1, Ar.sub.2 and Ar.sub.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 6 (depends on 4)

A papery product as claimed in claim 4, wherein said Ar.sub.1, Ar.sub.2 and Ar.sub.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.sup.2 represents a member selected from ##STR21## wherein Y.sup.2 is hydrogen or alkyl having 1 to 3 carbon atoms.

### Claim 7 (depends on 4)

A papery product as claimed in claim 4, wherein said wholly aromatic polyamide contains repeating units of the formula (II) in which said Ar.sub.2 and Ar.sub.3 are independently m-phenylene or p-phenylene.

### Claim 8 (depends on 7)

A papery product as claimed in claim 7, wherein Ar.sub.2 and Ar.sub.3 are m-phenylene.