# US 10,501,325 B2 · Fabrication of a graphite film based on a polyimide film

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- Number: US 10,501,325 B2
- Document ID: US10501325B2
- Status: Granted
- Kind: B2
- Application number: 15/372,026
- Filed: 2016-12-07
- Published: 2018-05-10
- Granted: 2019-12-10
- Earliest claimed: 2016-11-10
- Assignees: Taimide Technology Incorporation
- Applicants: Taimide Technology Incorporation
- Inventors: Jia-Hao Wu; Yu-Chen Lai
- Web page: https://patentgrep.com/patent/US10501325B2

## CPC

- C01B 32/205: Preparation
- C08J 9/0066: {Use of inorganic compounding ingredients}
- C08J 9/26: by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out
- C08J 2201/044: Elimination of an inorganic solid phase
- C08J 2379/08: Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- 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)

## Abstract

A polyimide film suitable for use in the fabrication of a graphite layer includes a polyimide derived from reaction of diamine monomers with dianhydride monomers, and a foaming agent incorporated in the polyimide. Moreover, a process of fabricating a graphite film includes providing a polyamic acid solution formed by reaction of diamine monomers with dianhydride monomers, incorporating a foaming agent into the polyamic acid solution, forming a polyimide film from the polyamic acid solution, applying a first thermal treatment so that the polyimide film is carbonized to form a carbon film, and applying a second thermal treatment so that the carbon film is converted to a graphite film.

## Claims

### Claim 1

A process of fabricating a graphite film, comprising:
providing a polyamic acid solution formed by reaction of diamine monomers with dianhydride monomers;
incorporating a foaming agent into the polyamic acid solution, wherein the foaming agent includes boron nitride and is incorporated in a quantity between 0.02 wt % and 0.4 wt % based on a total weight of the polyimide film;
forming a polyimide film from the polyamic acid solution containing the foaming agent;
applying a first thermal treatment so that the polyimide film is carbonized to form a carbon film; and
applying a second thermal treatment so that the carbon film is converted to a graphite film.

### Claim 2 (depends on 1)

The process of claim 1, wherein the diamine monomers are selected from the group consisting of 4,4′-oxydianiline (4,4′-ODA), phenylenediamine (p-PDA), 2,2′-bis(trifluoromethyl)benzidine (TFMB), 1,3-bis(4-aminophenoxy)benzene (TPER), 1,4-bis(4-aminophenoxy)benzene (TPEQ), 2,2′-dimethyl[1,1′-biphenyl]-4,4′-diamine (m-TB-HG), 1,3′-bis(3-aminophenoxy) benzene (APBN), 3,5-diamino benzotrifluoride (DABTF), 2,2′-bis[4-(4-aminophenoxy) phenyl]propane (BAPP), 6-amino-2-(4-aminophenyl) benzoxazole (6PBOA) and 5-amino-2-(4-aminophenyl) benzoxazole (5PBOA), and the dianhydride monomers are selected from the group consisting of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), 2,2-bis [4-(3,4dicarboxyphenoxy) phenyl] propane dianhydride (BPADA), pyromellitic dianhydride (PMDA), 2,2′-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), 4,4-oxydiphthalic anhydride (ODPA), and benzophenonetetracarboxylic dianhydride (BTDA), 3,3′,4,4′-dicyclohexyltetracarboxylic acid dianhydride (HBPDA).

### Claim 3 (depends on 1)

The process of claim 1, wherein the first thermal treatment is performed at a temperature between about 800° C. and about 1500° C.

### Claim 4 (depends on 1)

The process of claim 1, wherein the second thermal treatment is performed at a temperature between about 2300° C. and about 3000° C.