POLYMER FILM, SOLUTION CASTING METHOD AND APPARATUS

摘要

Air is flown above a casting film. Further, plural guide boards are provided between an aeration duct and an emission duct in order to control the direction of air flow. The air passes through the direction at which the casting film moves. If the thickness data of the obtained film are continuously measured along the direction (except 90°) intersecting a longitudinal direction, the thickness unevenness is at most ±2 mum when a thickness average is considered as a standard value zero and the value V is at most 300x10^-5. V is calculated on the formula V=Sigma{(dYn)/(dXn²/n, when the thicknesses at each point is defined as Yn, the each distance is defined as Xn between the said starting measuring point PS 1 and each selected point. These points are selected on the line of the thickness data.