# US 10,501,594 B2 · Graphite film and method for producing graphite film

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- Number: US 10,501,594 B2
- Document ID: US10501594B2
- Status: Granted
- Kind: B2
- Application number: 15/346,264
- Filed: 2016-11-08
- Published: 2017-02-23
- Granted: 2019-12-10
- Earliest claimed: 2011-08-24
- Assignees: Kaneka Corporation
- Applicants: Kaneka Corporation
- Inventors: Yusuke Ohta; Takashi Inada; Makoto Kutsumizu; Yasushi Nishikawa; Satoshi Katayama
- Web page: https://patentgrep.com/patent/US10501594B2

## CPC

- C08J 5/18: Manufacture of films or sheets
- C01B 32/20: Graphite
- C01B 32/205: Preparation
- C08G 73/105: {with oxygen only in the diamino moiety}
- C08G 73/1071: {Wholly aromatic polyimides containing oxygen in the form of ether bonds in the main chain}
- C08J 2379/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

It is possible to obtain a graphite film with its shape controlled, by performing a sag controlling step of controlling temperatures of a polymer film at both widthwise ends and a temperature of the polymer film in a widthwise middle portion within a temperature range from a starting temperature of thermal decomposition of the polymer film to a sag controlling temperature of the polymer film.

## Claims

### Claim 1

A method for producing a graphite film, comprising:
a sag controlling step of controlling (i) temperatures of a polymer film at both widthwise ends and (ii) a temperature of the polymer film in a widthwise middle portion within a temperature range from a starting temperature of thermal decomposition of the polymer film to a sag controlling temperature of the polymer film; and
a step of treating the film obtained in the sag controlling step with heat at a temperature of 2000° C. or higher after the sag controlling step,
wherein the sag controlling step comprises treating the polymer film with heat so that the temperatures (i) are higher than the temperature (ii) within the temperature range from the starting temperature of thermal decomposition of the polymer film to the sag controlling temperature of the polymer film and so that a temperature gradient over an area extending from the both widthwise ends of the polymer film toward the widthwise middle portion of the polymer film is not less than 2.5° C./m, and
the film obtained in the sag controlling step is treated with heat at a temperature of 2000° C. or higher after the sag controlling step, and
wherein the sag controlling step treats the polymer film with heat under a condition that the temperature gradient over an area extending from the both widthwise ends of the polymer film toward the widthwise middle portion of the polymer film is not less than 2.5° C./m and not more than 100° C./m.

### Claim 2 (depends on 1)

The method according to claim 1, wherein
in the sag controlling step, the polymer film is treated with heat while being moved through a heat treatment apparatus.

### Claim 3 (depends on 1)

The method according to claim 1, wherein
a temperature gradient over an area extending from one of the both widthwise ends of the polymer film toward the widthwise middle portion of the polymer film is identical to a temperature gradient over an area extending from the other of the both widthwise ends of the polymer film toward the widthwise middle portion of the polymer film.

### Claim 4 (depends on 1)

The method according to claim 1, wherein
a temperature gradient over an area extending from one of the both widthwise ends of the polymer film toward the widthwise middle portion of the polymer film is different from a temperature gradient over an area extending from the other of the both widthwise ends of the polymer film toward the widthwise middle portion of the polymer film.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the sag controlling step treats the polymer film with heat under a condition that the temperature gradient over the area extending from the both widthwise ends of the polymer film toward the widthwise middle portion of the polymer film is not less than 10° C./m and not more than 50° C./m.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the polymer film has a width in the range from 50 to 300 mm.