# US 2020/0399789 A1 · Carbon fiber bundle and production method therefor

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- Number: US 2020/0399789 A1
- Document ID: US20200399789A1
- Status: Published application
- Kind: A1
- Application number: 16/975,159
- Filed: 2019-03-05
- Published: 2020-12-24
- Earliest claimed: 2018-03-06
- Assignees: Toray Industries, Inc.
- Applicants: Toray Industries, Inc.
- Inventors: Haruki Okuda; Jun Watanabe; Fumihiko Tanaka
- Web page: https://patentgrep.com/patent/US20200399789A1

## CPC

- D01F 9/22: from polyacrylonitriles
- D01F 9/225: {from stabilised polyacrylonitriles}
- D01F 6/18: from polymers of unsaturated nitriles, e.g. polyacrylonitrile, polyvinylidene cyanide
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS

## Abstract

A carbon fiber bundle that satisfies retaining a twist count of 2 turns/m or more when suspended with one end fixed and the other end free; having a single fiber diameter of 6.1 μm or more and a heat loss rate at 450° C. of 0.15% or less, and formula (1) wherein Lc is crystallite size and π002 is an orientation parameter of crystallites determined from bulk measurement of the entire fiber bundle: π002>4.0×Lc+73.2 (1); and a carbon fiber bundle that satisfies: retaining a surface layer twist angle of 0.2° or more when suspended with one end fixed and the other end free; having a single fiber diameter of 6.1 μm or more and a heat loss rate at 450° C. of 0.15% or less, and formula (1).

## Claims

### Claim at position 1

1-10. (canceled)

### Claim 11

A carbon fiber bundle that satisfies: retaining a twist count of 2 turns/m or more when suspended with one end fixed and the other end free; having a single fiber diameter of 6.1 μm or more and a heat loss rate at 450° C. of 0.15% or less, and formula (1) wherein Lc is crystallite size and π002 is an orientation parameter of crystallites determined from bulk measurement of the entire fiber bundle:
π002>4.0×Lc+73.2 (1).

### Claim 12 (depends on 11)

The carbon fiber bundle as set forth in claim 11, wherein the remaining twist count is 16 turns/m or more.

### Claim 13

A carbon fiber bundle that satisfies: retaining a surface layer twist angle of 0.2° or more when suspended with one end fixed and the other end free; having a single fiber diameter of 6.1 μm or more and a heat loss rate at 450° C. of 0.15% or less, and formula (1) wherein Lc is crystallite size and π002 is an orientation parameter of crystallites determined from bulk measurement of the entire fiber bundle:
π002>4.0×Lc+73.2 (1).

### Claim 14 (depends on 13)

The carbon fiber bundle as set forth in claim 13, wherein the remaining fiber bundle surface layer twist angle is 2.0° or more.

### Claim 15 (depends on 11)

A carbon fiber bundle as set forth in claim 11, wherein the strand elastic modulus is 200 GPa or more.

### Claim 16 (depends on 11)

The carbon fiber bundle as set forth in claim 11, wherein the strand elastic modulus is 240 GPa or more.

### Claim 17 (depends on 11)

The carbon fiber bundle as set forth in claim 11, wherein the filament number is 10,000 or more.

### Claim 18

A method of producing a carbon fiber bundle having a single fiber diameter of 6.1 μm or more and a heat loss rate at a temperature of 450° C. of 0.15% or less, comprising:
performing stabilization of a precursor fiber bundle for polyacrylonitrile based carbon fiber, pre-carbonization thereof, and
carbonization thereof performed in this order, a twist count and tension of the fiber bundle being 2 turns/m or more and 1.5 mN/dtex or more, respectively, in the carbonization step.

### Claim 19

A method of producing a carbon fiber bundle retaining a surface layer twist angle of 0.2° or more when suspended with one end fixed and the other end free and having a single fiber diameter of 6.1 μm or more and a heat loss rate at a temperature of 450° C. of 0.15% or less, comprising:
performing stabilization of a precursor fiber bundle for polyacrylonitrile based carbon fiber, pre-carbonization thereof, and
carbonization thereof performed in this order, tension of the fiber bundle being 1.5 mN/dtex or more in the carbonization step.

### Claim 20 (depends on 18)

The method as set forth in claim 18, wherein the filament number of the carbon fiber bundle is 10,000 or more in the carbonization step.

### Claim 21 (depends on 19)

The method as set forth in claim 19, wherein the filament number of the carbon fiber bundle is 10,000 or more in the carbonization step.

### Claim 22 (depends on 12)

A carbon fiber bundle as set forth in claim 12, wherein the strand elastic modulus is 200 GPa or more.

### Claim 23 (depends on 12)

The carbon fiber bundle as set forth in claim 12, wherein the strand elastic modulus is 240 GPa or more.

### Claim 24 (depends on 12)

The carbon fiber bundle as set forth in claim 12, wherein the filament number is 10,000 or more.