Process of patch coating of catalyst layers using mask

Abstract

Methods of selective area coating (patch coating) of a catalyst layer which matches the cell active area to improve utilization of the precious metal catalysts for CCM manufacturing are described. An adhesive or non-adhesive polymer film may be cut into the desired patch shape and size to create the mask. The mask is then assembled onto the membrane surface using the adhesive of the adhesive polymer film or hot pressing the non-adhesive polymer film. The catalyst coating layer is applied to the membrane/mask assembly and dried. The mask is removed, leaving the patch coated CCM. The process can be repeated to coat the other side of the membrane, if desired.

What is claimed is: 
     
         1 . A method of making a catalyst coated membrane comprising a patch coated catalyst layer comprising:
 applying a first film mask having a first open area to a first side of a membrane;   applying a first catalyst coating layer to a surface of the mask and the open area on the first side of the membrane;   drying the first catalyst coating layer; and   removing the mask forming the catalyst coated membrane comprising a first patch coated catalyst layer on the first side of the membrane.   
     
     
         2 . The method of  claim 1  further comprising:
 applying a second film mask having a second open area to a second side of the membrane; 
 applying a second catalyst coating layer to a surface of the second film mask and the second open area on the second side of the membrane; 
 drying the second catalyst coating layer; 
 removing the second mask forming the catalyst coated membrane comprising the first patch coated catalyst layer on the first side of the membrane and a second patch coated catalyst layer on the second side of the membrane; and 
 wherein the first patch coated catalyst layer and the second patch coated catalyst layer are coextensive. 
 
     
     
         3 . The method of  claim 1  further comprising:
 applying a backing layer to a second side of the membrane before applying the first mask, wherein the backing layer comprises a polymeric film comprising nylon, polyimide, polyetherimide, polyethylene, polypropylene, polyethylene-co-polypropylene, polyamide, poly(vinyl chloride), poly(vinyl alcohol), polycarbonate, polyimide, polylactic acid, polyethylene terephthalate, poly(ether ether ketone), poly(methyl methacrylate), polyphenylene sulfone, polysulfone, polyethersulfone, polystyrene, poly(vinyl acetate), polychlorotrifluoroethylene, polytetrafluoroethylene, acrylonitrile butadiene styrene, poly(vinylidene fluoride), or combinations thereof. 
 
     
     
         4 . The method of  claim 3  further comprising:
 removing the backing layer from the second side of the membrane before applying a second film mask having a second open area to a second side of the membrane. 
 
     
     
         5 . The method of  claim 4  further comprising:
 applying a second backing layer to the first side of the membrane after applying the second film mask and before applying a second catalyst coating layer to a surface of the second film mask and the second open area on the second side of the membrane. 
 
     
     
         6 . The method of  claim 1  further comprising:
 applying a second film mask having a second open area to a second side of the membrane after drying the first catalyst coating layer; 
 applying a second catalyst coating layer to a surface of the second mask and the second open area on the second side of the membrane; and 
 drying the second catalyst coating layer. 
 
     
     
         7 . The method of  claim 6  further comprising:
 removing the second mask forming the catalyst coated membrane comprising the first patch coated catalyst layer on the first side of the membrane and a second patch coated catalyst layer on the second side of the membrane; and 
 wherein the first patch coated catalyst layer and the second patch coated catalyst layer are coextensive. 
 
     
     
         8 . The method of  claim 1  wherein the first mask comprises a polymeric film layer with an adhesive layer on one surface of the film, and wherein the adhesive layer comprises an acrylic adhesive or a silicone adhesive. 
     
     
         9 . The method of  claim 1  wherein the first mask comprises a non-adhesive polymeric film having a glass transition temperature lower than a glass transition temperature of the membrane. 
     
     
         10 . The method of  claim 9  wherein the non-adhesive polymeric film has a glass transition temperature in a range of 30-150° . 
     
     
         11 . The method of  claim 9  wherein the non-adhesive polymeric film comprises nylon, polyamide, poly(vinyl chloride), poly(vinyl alcohol), polycarbonate, polyimide, polylactic acid, polyethylene terephthalate, poly(ether ether ketone), poly(methyl methacrylate), polyphenylene sulfone, polysulfone, polyethersulfone, polystyrene, poly(vinyl acetate), polychlorotrifluoroethylene, polytetrafluoroethylene, acrylonitrile butadiene styrene, poly(vinylidene fluoride), or combinations thereof. 
     
     
         12 . The method of  claim 1  wherein applying the mask comprises applying heat or pressure or both to the mask. 
     
     
         13 . The method of  claim 1  further comprising:
 recovering the catalyst from the catalyst-coated mask after the mask is removed; and 
 recycling the recovered catalyst. 
 
     
     
         14 . The method of  claim 1  wherein the mask has a plurality of open areas. 
     
     
         15 . The method of  claim 1  wherein the open area of the mask has a shape of a circle, a square, a square with rounded corners, a triangle, a triangle with rounded corners, a rectangle, or a rectangle with rounded corners. 
     
     
         16 . The method of  claim 1  wherein the mask surface is hydrophilic. 
     
     
         17 . The method of  claim 1  further comprising:
 applying a second catalyst coating to a second side of the catalyst coated membrane before applying the first catalyst coating layer or after applying the first catalyst coating layer. 
 
     
     
         18 . The method of  claim 1  wherein the catalyst coating is applied using Mayer rod coating, screen printing, blade coating, spray coating, dip coating, gravure coating, slot die coating, comma coating, or combinations thereof. 
     
     
         19 . The method of  claim 1  wherein the membrane is a proton exchange membrane, an anion exchange membrane, or a bipolar membrane, and wherein the membrane comprises a fluoropolymer, a non-fluoropolymer, or a combination thereof. 
     
     
         20 . A method of making a catalyst coated membrane comprising a patch coated catalyst layer comprising:
 applying a backing layer to a second side of a membrane;   applying a first film mask having a first open area to a first side of the membrane;   applying a first catalyst coating layer to a surface of the mask and the open area on the first side of the membrane;   drying the first catalyst coating layer;   removing the backing layer from the second side of the membrane;   applying a second film mask having a second open area to the second side of the membrane;   applying a second catalyst coating layer to a surface of the second film mask and the second open area on the second side of the membrane;   drying the second catalyst coating layer;   removing the first and the second masks forming the catalyst coated membrane comprising the first patch coated catalyst layer on the first side of the membrane and a second patch coated catalyst layer on the second side of the membrane; and   wherein the first patch coated catalyst layer and the second patch coated catalyst layer are coextensive.