Patent ID: 6171658
Filing Date: 2001-01-09
Classification: B05C,B05D,G03C

Abstract:
A method for coating a liquid composition to a web substrate at a coating application point while moving in contact with and around a coating roller to form a coating on a surface of the web substrate, comprising the steps of:a) setting a characteristic electrical length (.lambda.) to be less than about 400 .mu.m by varying one or more of the parameters of the surface resistance (.rho..sub.S) on the surface of the web substrate to be coated, the web capacitance per unit area (C) of the web substrate in contact with the coating roller, and the coating speed (U) for said web substrate wherein .lambda. is determined by the equation .lambda.=(.rho..sub.S CU).sup.-1 ;b) controlling the voltage on the surface of the web (V.sub.S) by controlling the voltage applied to the coating roller (V.sub.R) using the equation V.sub.S =V.sub.R (1-e.sup.x/.lambda.) wherein e is a constant and x is a distance before the coating application point on the web substrate and is in the range of from about 50 .mu.m to about 100 .mu.m; andc) delivering said liquid composition from a coating die to said web substrate at said coating application point traveling at said speed U to form a coated web substrate.