Method during paper manufacturing of using a cationic starch composition comprised of cationic starch and carboxymethylcellulose or polyacrylic as well as the liquid for this.

摘要

The invention refers to a method of increasing retention and binding of pigment during paper manufacturing. The new method is characterized by that one introduces, into pigment slurry with or without fibres, a colloidal solution of an amphoteric starch composition also containing cationic amine groups such as anionic acid groups, whereby the named starch composition is layered onto the pigment surfaces like an amphoteric gel coat with limited strength. Thereafter setting up a non-organic polycationic or polyanionic union for agglomeration and development of a considerably stronger membrane gel outside of the gel coated pigment particles. The thus treated pigment suspension is used in the usual manner for paper manufacturing. For the invention, usual pigments such as kaolin, chalk, talc, titanium dioxide as well as fibre-shaped minerals such as asbestos and wollastonite can be used. Suitable amphoteric starch compounds are products of reactions between cationic starches and compounds such as carboxymethylcellulose or polyacrylic acid. Among the non-organic polyionic compounds, which are suitable for the development of solid gel membrane these include polyaluminum salts and silicic acid preferably in oligomers or polymer form.IMAGE