METHOD FOR ESTIMATING DRYING STATE OF COATING FILM

PROBLEM TO BE SOLVED: To provide a method for optimally estimating a drying state of a coating film after the thickness of the coating film reaches the same thickness of a porous body (coating film after completely dried) by evaporation of (part of) a solvent.SOLUTION: In the method, a paste obtained by mixing particles and a solvent is deposited on a surface of a base material, so as to form a coating film made of the paste on the surface of the base material, and thereafter, a drying state of the coating film during a period of formation of a porous body having the particles is estimated through drying the coating film. In the method, after the thickness of the coating film reaches the same thickness as the porous body by evaporation of part of the solvent, in an equation (1) being an equation of a vapor-liquid two phase flow within the porous body, solvent density C is converted into a mathematical expression expressed by an equation (2), and effective diffusion coefficient Dof a vapor phase of the solvent is converted into a mathematical expression expressed by an equation (3), and a saturation degree s is calculated from the converted equation.