Patent ID: 6680084
Filing Date: 2004-01-20
Classification: B05D,D21H

Abstract:
A method of forming an oriented multilayer polymeric film on a substrate, comprising the steps of:a) conveying a substrate along a predetermined path at a predetermined travelling speed and in a predetermined travelling direction; b) coating the substrate with a polymer dispersion containing polymer particles and a liquid dispersing medium to form on said substrate a first coating of said dispersion; c) contacting said first coating with a first particle orienting roller driven for rotation about a first longitudinal axis thereof independently of said substrate so as to have a first tangential speed at a surface of the coated substrate, said first particle orienting roller having a first particle orienting pattern arranged at a first angle relative to the travelling direction of said substrate to cause orientation of the polymer particles of said first coating along a first predetermined direction; d) drying said first coating to cause evaporation of said liquid dispersing medium and formation of a first layer of oriented polymer particles on said substrate; and e) successively forming on said first layer at least one further layer of oriented polymer particles, each further layer being formed by: i) coating a previously formed underlying layer of oriented polymer particles with said polymer dispersion to form on said underlying layer a further coating of said dispersion; ii) contacting said further coating with a further particle orienting roller driven for rotation about a further longitudinal axis thereof independently of said substrate so as to have a further tangential speed at the surface of the coated substrate, said further particle orienting roller having a further particle orienting pattern arranged at a further angle relative to the travelling direction of said substrate to cause orientation of the polymer particles of said further coating along a further predetermined direction; and iii) drying said further coating to cause evaporation of said liquid dispersing medium and formation of said further layer of oriented polymer particles on said underlying layer; wherein at least one said further angle is different from said first angle or at least one said further tangential speed is different from said first tangential speed, thereby forming on said substrate an oriented multilayer polymeric film having at least two layers of polymer particles oriented along two different directions with respect to one another.