| 摘要 |
PURPOSE:To orient a surfactant to the surface of a coating liquid to a saturation value and enable stable and sufficient display of the function of the surfactant with a small addition quantity, by a method wherein the period of time required for passage from a coating part to a drying part is set to be not shorter than the period of time required for the surfactant to be oriented to the surface of the coating liquid in a coating environment ranging from the coating part to the drying part. CONSTITUTION:The period of time required for passage from a coating part to a drying part is set to be not shorter than the period of time required for a surfactant to migrate from a liquid to a gas-liquid surface and reach a equilibrium state. During the passage from the coating part to the drying part, the surfactant is oriented to the surface of the coating liquid to a saturation value, and it is fixed by drying in the oriented state, whereby the function thereof is sufficiently displayed. The period of time required for the function of the surfactant to be stably developed is made to be orientation time. Most of commercial silicone or fluoro surfactants have a high mol.wt., and particularly when the surfactant has a higher mol.wt. or a greater molecular size, the migration of the surfactant in the coating liquid is slower, and the orientation time is longer, resulting in that the desired effect is displayed in the case of practical coating by use of a coater. |
