MICROPARTICLE TECHNOLOGY IN CLAYFILLED GROUNDWOOD SPECIALITY PRINTINGGRADES PRODUCED UNDER NEUTRAL OR ALKALINE CONDITIONS

The application of microparticle systems on groundwood paper grades ha s so far been limited due to insufficient performance of the added che micals. Laboratory experiments have shown that the reduced efficiency is caused by dissolved and colloidal compounds in the white water rath er than the pulping process. A microparticle system based on a new typ e of highly cationized starch (CS) and an anionic colloidal silica (AC S) has been developed. This system is less sensitive to various wet-en d contaminents present in the white water.