Patent ID: 7255896

Claim:
A method of producing a die coater structured with at least two bars so as to form a pocket section to extend a coating liquid in a coating width direction, a coating liquid supply port to supply a coating liquid to the pocket section, and a slit section to discharge a coating liquid from the pocket section to a material to be coated, wherein at least a part of a surface of the two bars coming in contact with a coating liquid is covered with a fluorine-based resin, the method comprising steps, sequentially in the following order, of: a first preheating step of conducting a preheating process for a bar with a first preheating temperature same as or higher than a baking temperature of 400° C. to 450° C. in a baking process in a covering process with the fluorine-based resin so as to remove residual machining stress in the bar; a grinding step of grinding the bar subjected to the first preheating step so as to remove deformation on the bar caused by the first preheating step; a covering process of covering the part of the surface of the bar with the fluorine-based resin so as to form a covered section, wherein the covering process comprises sequentially a second preheating step of cleaning the bar; wherein the second preheating temperature in the second preheating step is equal to or less than the baking temperature in the baking process; a coating process of coating the fluorine-based resin on the part to form the covered section and the baking process of baking the covered section, and a finishing step of finishing the covered section so as to have a straightness of 0.1 to 10 μm in a direction along the coating width, wherein the straightness is defined by JIS B0182.