Method and apparatus for coating a substrate

摘要

A coating method and apparatus in which a coating composition is uniformly coated onto a continuously moving web without accumulation of thickened composition in the coating head. Auxiliary supply pipes open into the cavity of the coating head at both ends of the cavity. Liquid is either supplied through the auxiliary supply pipes to the coating head, or a portion of the coating composition contained in the coating head is discharged through the auxiliary supply pipes. Preferably, the supply or discharge of the liquid through the auxiliary supply pipes is at a rate such that a ratio of a velocity component of the liquid flowing through the auxiliary supply pipes to that of the coating composition onto the moving web is in a range of 0.01 to 10.