Studies on the Water-Soluble Polymers VII

Abstract

The application of polyethyleneimine to paper making was studied in succession to the previous work.Polyethyleneimine was found to be combined with anionic water-soluble polymer such as sodium alginate, carboxymethyl cellulose and starch derivatives in aqueous solution to give a high molecular complex compound. The complex compound indicated the properties of cationic polyelectrolyte as a whole in many cases, because the cationic properties of polyethyleneimine are stronger than the anionic properties of above-mentioned polymers. The cationic complex polyelectrolyte was readily adsorbed at pulp fibers, for the fibers are slightly acidic in water. The adsorption was sufficiently effective in not only acidic but neutral and alkaline media.In paper making, the complex compound was found to be useful for fixing of strengthening agents of paper on pulp fibers in the presence or absence of aluminium sulfate, and gave a excellent dry and wet strength to the paper.Polyethyleneimine was also found to be useful for fixing of sizing agent on pulp fibers. It is especially effective interesting that it was effective to the sizing of paper of chemical fibers.Polyethyleneimine was able to be applied to the complete fixing of all kinds of sizing agent on paper.Sizing agent made of petroleum resin had been known to have a defect in comparatively easy blurring of ink in spite of its good Stockigt's sizing effect on paper. The defect was removed by using the fixing action of polyethyleneimine.