PROCESS FOR REDUCING THE WATER VAPOUR PERMEABILITY OF PAPER

摘要

The water vapor permeability of a sheet of paper is reduced by coating the paper sheet with a film of a water-based coating medium consisting of a wood-rosin sizing dispersion containing at least one additive improving the film-forming properties of the coating medium, the additive being selected from the group consisting of surfactants, paraffin waxes and ammonia, and subjecting the coated paper sheet to a thermal treatment at a temperature between 50 and 120.degree.C.