Electrode backing layer and method of preparing
AssigneeDiamond Shamrock Corporation
InventorsLawrence J. Gestaut, Frank Solomon
Life of this patent
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Abstract
This disclosure is directed to the preparation of cohesive, self-sustaining electrode backing layers by a method comprising mixing from about 20 to about 50 weight parts of polytetrafluoroethylene (PTFE) having a particle size ranging from 0.05 to 0.5 micron with from about 50 to about 80 weight parts of a partially fluorinated carbon black of the formula CF.sub.x, where x is from about 0.1 to about 0.18 and having particles of a size ranging from about 50 to about 3000 angstroms to produce an electrode backing layer having a combination of enhanced electrical conductivity and hydrophobicity.
Claims9
A method for preparing an electrically conductive, hydrophobic, cohesive, self-sustaining electrode wetproofing sheet for use with an oxygen cathode comprising the steps of:
- intimately mixing from about 50 to about 80 wt. percent partially fluorinated carbon black particles of the formula CF.sub.x, where x is from 0.1 to 0.18, with from about 20 to about 50 wt. percent of liquid dispersed polytetrafluoroethylenated particles, to form a polytetrafluoroethylenated carbon black mix that can include a wetting agent;
- drying the polytetrafluoroethylenated carbon black mix,
- removing any wetting agent associated with forming the polytetrafluoroethylenated carbon black mix;
- chopping the polytetrafluoroethylenated carbon mix to form a granular mix, and then
- forming the granular mix into a sheet by one of passing said granular mix through rollers heated to between about 65.degree. C. and 90.degree. C. and by dispersing said granular mix in a liquid dispersion medium capable of wetting said granular mix then filtering said granular mix from said dispersion on a salt bed-filter medium.
Dependencies are inferred from the claim text.