Paper and cardboard prodn. using filler - coated with quat. cationic starch-ether, giving improved pulp filler retention

摘要

In the prodn. of paper and cardboard, an inorganic filler is used which is coated with a polymer comprising a quat. cationic starch ether (I). Amt. of (I) is pref. 5- wt.% based on filler. The filler and (I) can be mixed dry and the mixt. then dispersed in water or the filler can be dispersed cold in a 5 wt.% soln. (wrt filler) of (I), the dispersion contg. 40-50% solids. For neutral or alkaline sizing, the soln. is pref. preflocculated by adding 0.2-1 wt.% Al sulphate wrt coated filler. The pulp has improved filler retention during filtration and filler content can also be increased, resulting in a prod. with improved mechanical strength and impermeability.