# US 5,352,524 A · Carbon film and process for preparing the same

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- Number: US 5,352,524 A
- Document ID: US5352524A
- Status: Granted
- Kind: A
- Application number: 07/890,155
- Filed: 1992-05-29
- Granted: 1994-10-04
- Earliest claimed: 1991-05-31
- Assignees: Toho Rayon Co., Ltd.
- Inventors: Yasuhisa Nagata
- Web page: https://patentgrep.com/patent/US5352524A

## CPC

- C04B 35/524: obtained from polymer precursors, e.g. glass-like carbon material
- Y10T 428/30: Self-sustaining carbon mass or layer with impregnant or other layer
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

(1) A carbon film derived from a polyimide film, which has a tensile strength of at least 15 Kgf/mm.sup.2, a tensile modulus of elasticity of at least 5000 Kgf/mm.sup.2 and an electric conductivity of at least 200 S/cm. (2) A process for preparing a carbon film which comprises the following steps: 1) reacting a monomer combination selected from the group consisting of a combination comprising a tetracarboxylic acid dianhydride and an aromatic diamine and a combination comprising a tetracarboxylic acid dianhydride, an aromatic diamine, and a polyamino compound having at least three amino groups to form a polyamic acid; 2) forming a film of polyamic acid; 3) imidizing the polyamic acid film to form a polyimide film having a tensile strength of at least 10 Kgf/mm.sup.2 and a tensile modulus of elasticity of at least 500 Kgf/mm.sup.2 ; and 4) carbonizing the polyimide film in an inert gas or in a vacuum until a carbon film having a tensile strength of at least 15 Kgf/mm.sup.2, a tensile modulus of elasticity of at least 5000 Kgf/mm.sup.2 and an electric conductivity of at least 200 S/cm is formed.

## Claims

### Claim 1

A carbon film derived from a polyimide film, which has a tensile strength of at least 15 Kgf/mm.sup.2, a tensile modulus of elasticity of at least 5000 Kgf/mm.sup.2 and an electric conductivity of at least 200 S/cm.

### Claim 2 (depends on 1)

The carbon film as claimed in claim 1, wherein the tensile strength is at most 100 Kgf/mm.sup.2, the tensile modulus of elasticity is at most 20,000 Kgf/mm.sup.2, and the electric conductivity is at most 2,000 S/cm.

### Claim 3 (depends on 1)

The carbon film as claimed in claim 1, wherein said polyimide is obtained by imidizing a polyamic acid selected from the group consisting of: (1) a polycondensation product of a tetracarboxylic acid dianhydride and an aromatic diamine; and, (2) a polycondensation product of a tetracarboxylic acid dianhydride, an aromatic diamine and a polyamino compound having at least three amino groups.

### Claim 4 (depends on 1)

The carbon film as claimed in claim 1, which has a density of at least 1.7 g/cm.sup.3, a carbon amount of at least 85 wt %, and an amount of each of hydrogen, oxygen and nitrogen of 10 wt % or less.

### Claim 5 (depends on 1)

The carbon film as claimed in claim 1, which has a nitrogen amount of at least 0.5 wt %.

### Claim 6 (depends on 1)

The carbon film as claimed in claim 1, which has an electric conductivity of at most 800 S/cm.