# US 5,702,993 A · Triaxial fabric composed of carbon fiber strands and method for production thereof

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- Number: US 5,702,993 A
- Document ID: US5702993A
- Status: Granted
- Kind: A
- Application number: 08/669,498
- Filed: 1996-07-03
- Granted: 1997-12-30
- Earliest claimed: 1994-11-04
- Assignees: Nippon Steel Corporation; Sakase Adteck Co.
- Inventors: Kenji Kubomura; Hiromi Kimura; Hirotaka Shibata
- Web page: https://patentgrep.com/patent/US5702993A

## CPC

- B29C 70/22: oriented in at least two directions forming a two-dimensional [2D] structure
- D03D 13/002: {With diagonal warps or wefts}
- D03D 15/52: thermal insulating, e.g. heating or cooling
- Y10S 428/902: High modulus filament or fiber
- Y10T 428/30: Self-sustaining carbon mass or layer with impregnant or other layer
- Y10T 442/3187: Triaxially woven fabric
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- D03D: WOVEN FABRICS; METHODS OF WEAVING; LOOMS
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A triaxial fabric composed of carbon fiber strands is provided, which has a crimp releasing ratio (L'-L)/L satisfying ›(L.sub.0 -L)/L.sub.0 !.times.0.7.gtoreq.(L'-L)/L.gtoreq.0. Since the crimps of the fiber strands composing the fabric are preliminarily fixed, fiber breakage due to abrasion in the intersecting portions of the fabric is prevented, whereby a high quality triaxial fabric is obtained. A method for the production of such a fabric is also provided.

## Claims

### Claim 1

A triaxial fabric wherein two sets of warp yarns (bias yarns) of carbon fiber strands are interwoven with one set of weft yarns (0.degree. directional yarns) of carbon fiber strands having the same cross-sectional area as the bias yarn and arranged in the widthwise direction of the fabric, characterized in that the fabric has a crimp releasing ratio (L'-L)/L, after being subjected to a heat treatment at 1800.degree. C. in an inert gas atmosphere, satisfying the following equation:
(L.sub.0 -L)/L.sub.0 .times.0.07.gtoreq.(L'-L)/L.gtoreq.0
wherein L is a apparent length of the weft yarn composing the triaxial fabric; L.sub.0 is a length of the weft yarn along the crimp; and L' is an apparent length of the weft yarn when removed from the fabric.

### Claim 2 (depends on 1)

A triaxial fabric as defined by claim 1, characterized in that the triaxial fabric is composed solely of carbon fiber strands originated from a mesophase pitch.

### Claim 3 (depends on 1)

A triaxial fabric as defined by claim 1, characterized in that the triaxial fabric is of a basic structure.

### Claim 4 (depends on 1, 2, 3)

A triaxial fabric as defined by any one of claims 1 through 3, characterized in that the areal weight (fabric weight per unit area) of the triaxial fabric is in a range between 45 g/m.sup.2 and 300 g/m.sup.2 and the tensile elastic modulus of a triaxial fabric composite prepared by impregnating the fabric with a resin is 3 tf/mm.sup.2 or more.

### Claim 5 (depends on 1, 2, 3, 4)

Single-layered and multi-layered composites such as a honeycomb sandwich structure for an artificial satellite or the like formed of the triaxial fabric as defined by any one of claims 1 through 4.

### Claim 6

A method for producing a triaxial fabric characterized in that carbon fiber strands having a tensile strength of 300 kgf/mm.sup.2 or more, a tensile strain at break of 0.6% or more and a tensile modulus of 15 tf/mm.sup.2 or more are woven into a triaxial fabric, which then is subjected to a heat treatment in an inert gas atmosphere at a temperature of 1800.degree. C. or more.

### Claim 7 (depends on 6)

A method for producing a triaxial fabric as defined by claim 6, characterized in that carbon fibers originated from a mesophase pitch are used as a starting material.

### Claim 8 (depends on 7)

A method for producing a triaxial fabric as defined by claim 7, characterized in that the linear density (fiber weight in a unit length) of the fiber strand composing the triaxial fabric is in a range between 40 g/km and 300 g/km.