Effect of white water composition on strength and runnability of wet paper

Dissolved and colloidal substances in mill waters are known to have effect on retention and drainage in the wet end of a paper machine and on the properties of dry paper. The effects of these substances on wet paper in laboratory scale were studied in this paper. The pulp studied was bleached softwood kraft pulp. The properties of the wet paper were measured using standard and high speed strain rate. The tension holding capacity has been found to be a good indicator for runnability of wet paper. The results show that the surface tension of white water varied according to the chemicals used. The surface tension of the deionized water dropped considerably during the recirculation due to the colloidal and dissolved materials released from the chemical pulp