Method of making coated or impregnated paper or paperboard

摘要

A method for making a surface coated or impregnated paper or paperboard by applying an aqueous additive dispersion to the wet web between the press and drying sections of a conventional paper or paperboard making machine. The aqueous additive dispersion is pre-metered onto a transfer roll and is applied to the wet web at a pressure nip between the transfer roll and a back-up roll. High solids content dispersions can be applied at high web speeds without tearing the web. The use of a high solids content aqueous dispersion having a solids content substantially equal to the solids content of the wet web at the point of application permits the method to be performed without increasing the drying load and therefore at an unreduced speed. The method contemplates the use of a hydrophillic transfer roll running in a direction opposite to the web, permitting a saturant to be impregnated into the web, and has particular application to the production of containerboard treated with a lignosulfonate saturant to improve strength and surface character./!