Patent ID: 6902757

Claim:
A process for producing a membrane-electrode assembly for solid polymer electrolyte fuel cells comprising a polymer electrolyte membrane, and a cathode and an anode facing each other with the polymer electrolyte membrane interposed therebetween, each having a catalyst layer adjacent to the polymer electrolyte membrane, which comprises forming at least one of the catalyst layers of the cathode and the anode by using coating liquids containing a catalyst and an ion exchange resin, wherein a die equipped with an inlet to introduce the coating liquids and a linear exit from which the coating liquids are discharged, the die as a guide partition wall to compartmentalize the inlet into a plurality of compartments extending toward the linear exit, a plurality of coating liquids having different compositions is introduced from the inlet so that they are not mixed with each other and pass through the plurality of the compartments separately, and the compartmentalizing direction of the guide partition wall is slanted relative to the direction in which a substrate for coating which faces the linear exit moves relatively to the die, and at least one of the die and the substrate for coating is moved so that the substrate for coating relatively moves at substantially right angles to the longitudinal direction of the linear exit to coat the substrate for coating with the coating liquids to form the catalyst layer, thereby continuously changing the composition of the catalyst layer in at least some part in the longitudinal direction of the linear exit of the die.