# US 2019/0245218 A1 · Resin composition for dense fuel cell separators

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- Number: US 2019/0245218 A1
- Document ID: US20190245218A1
- Status: Published application
- Kind: A1
- Application number: 16/340,479
- Filed: 2017-09-21
- Published: 2019-08-08
- Earliest claimed: 2016-10-14
- Assignees: Nisshinbo Chemical Inc.
- Applicants: Nisshinbo Chemical Inc.
- Inventors: Fumio Tanno; Yasuhito Nakagawa
- Web page: https://patentgrep.com/patent/US20190245218A1

## CPC

- H01M 8/0226: in the form of mixtures
- C08K 3/04: Carbon
- C08K 5/3445: Five-membered rings
- C08L 61/06: of aldehydes with phenols
- C08L 63/04: Epoxynovolacs
- H01M 8/0213: Gas-impermeable carbon-containing materials
- H01M 8/0221: Organic resins; Organic polymers
- C08K 2201/005: Additives being defined by their particle size in general
- C08L 2203/20: use in electrical or conductive gadgets
- H01M 8/10: Fuel cells with solid electrolytes
- Y02E 60/50: Fuel cells
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The present invention is a resin composition for dense fuel cell separators, which contains a graphite powder and an epoxy resin component that contains a base material, a curing agent and a curing accelerator, and wherein: the graphite powder has a spring back of 20-70% and an average particle diameter d50 of 30-100 μm; and the curing accelerator is an imidazole compound that has an aryl group in the 2-position. This resin composition for dense fuel cell separators enables the achievement of a dense separator for fuel cells, which satisfies a predetermined performance even in cases where the separator is compression molded in a short time that is less than 10 seconds.

## Claims

### Claim 1

A resin composition for a dense fuel cell separator, comprising graphite powder and an epoxy resin component that includes a base resin, a curing agent and a curing accelerator,
wherein the graphite powder has a springback of between 20 and 70% and an average particle size d50 of from 30 to 100 μm, and
the curing accelerator is an imidazole compound having an aryl group at the 2 position.

### Claim 2 (depends on 1)

The resin composition for dense fuel cell separators of claim 1, wherein the springback is between 20 and 65%.

### Claim 3 (depends on 1)

The resin composition for dense fuel cell separators of claim 1, wherein the base resin is at least one resin selected from the group consisting of cresol-novolak epoxy resins and biphenyl epoxy resins.

### Claim 4 (depends on 1)

The resin composition for dense fuel cell separators of claim 1, wherein the curing agent is a novolak phenolic resin.

### Claim 5 (depends on 1)

The resin composition for dense fuel cell separators of claim 1, wherein the curing accelerator is an imidazole compound having a phenyl group at the 2 position.

### Claim 6 (depends on 1)

A dense fuel cell separator which is obtained by molding the resin composition for dense fuel cell separators of claim 1.

### Claim 7 (depends on 6)

The dense fuel cell separator of claim 6 which has a resistivity of not more than 15 mΩ·cm, a glass transition temperature of at least 135° C. and a flexural strength of at least 50 MPa.

### Claim 8 (depends on 6)

The dense fuel cell separators of claim 6 which has a total organic carbon (TOC) value of 7 ppm or less.

### Claim 9 (depends on 1)

A method for producing a dense fuel cell separator, comprising the step of compression molding the resin composition for dense fuel cell separators of claim 1.

### Claim 10 (depends on 9)

The method for producing a dense fuel cell separator of claim 9, wherein compression molding is carried out for a period of less than 10 seconds.