Coating processes – Electrical product produced – Fuel cell part
Reexamination Certificate
2001-12-19
2004-03-09
Talbot, Brian K. (Department: 1762)
Coating processes
Electrical product produced
Fuel cell part
C427S180000, C427S372200, C427S205000
Reexamination Certificate
active
06703068
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an aqueous coating composition useful for making a gas diffusion layer for an electrochemical cell such as a fuel cell, which layer is advantageously free of surfactant residue. The coating composition comprises carbon particles, one or more highly fluorinated polymers, and one or more amine oxide surfactants.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 6,127,059 describes the use of Triton™ X100, an alcohol alkoxylate, as a surfactant when coating a gas diffusion layer for use in an electrochemical cell with a fluororesin containing carbon black.
SUMMARY OF THE INVENTION
Briefly, the present invention provides an aqueous coating composition comprising carbon particles, one or more highly fluorinated polymers and one or more amine oxide surfactants, typically an amine oxide surfactant according to formula I:
where n is 9 to 19.
In another aspect, the present invention provides a method of making a gas diffusion layer for an electrochemical cell comprising the steps of: a) coating a electrically conductive porous substrate with the aqueous coating composition according to the present invention, and b) heating the electrically conductive porous substrate to a temperature sufficient to decompose the amine oxide surfactants.
In another aspect, the present invention provides a gas diffusion layer for an electrochemical cell made according to the method of the present invention which typically contains no surfactant.
What has not been described in the art, and is provided by the present invention, is a coating composition and method of using same which contains a decomposing amine oxide surfactant and can therefore provide a surfactant-free gas diffusion layer.
In this application:
“vehicle” means a fluid which carries the particulate in a dispersion, which typically includes water or an alcohol;
“highly fluorinated” means containing fluorine in an amount of 40 wt % or more, but typically 50 wt % or more, and more typically 60 wt % or more; and
“substituted” means, for a chemical species, substituted by conventional substituents which do not interfere with the desired product or process, e.g., substituents can be alkyl, alkoxy, aryl, phenyl, halo (F, Cl, Br, I), cyano, nitro, etc.
It is an advantage of the present invention to provide a coating composition and method of using same which contains an effective surfactant which is ephemeral in use, and therefore capable of providing a surfactant-free gas diffusion layer.
REFERENCES:
patent: 4670363 (1987-06-01), Whitney et al.
patent: 6127059 (2000-10-01), Kato
patent: 6280871 (2001-08-01), Tosco et al.
patent: 6465041 (2002-10-01), Frisk et al.
patent: 6524736 (2003-02-01), Sompalli et al.
patent: 44985 (1994-02-01), None
Birkhorst Dieter
Boand Wayne Meredith
Frisk Joseph William
Hintzer Klaus
Larson James Michael
3M Innovative Properties Company
Dahl Philip Y.
Talbot Brian K.
LandOfFree
Amine oxide coating compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Amine oxide coating compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Amine oxide coating compositions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3238819