Pressure sensitive copying paper - coated on both sides with aq. wax compsn. and contg. colourant in front coating

摘要

A pressure sensitive copying paper has both front and back sides coated with a wax-based aqs. compsn., the front coating also contg. a colourant which imparts the desired shade to the front side of the paper, Pref. the front coating comprises 49.5-99% wax, 0-49.5% shear stabiliser for the wax, is not >1% colourant and opt. a small amt. of antifoaming agent. The back coating pref. comprises 1-3.5% wax, >=90% inorganic fillers, 3-6% colourant transferable under pressure and =0.5% thickening agent. The copying papers may be used both for 'autonomous' and 'contact' transfer. A large number of copies may be obtd. even when the base paper support is thin and porous and is prepd. from low grade fibrous compsns. partic. from old papers. The coatings may be applied on conventional paper-making machines using e.g. 'champion' bars.