PAPERMAKING ADDITIVE

摘要

A new class of polymeric additives for papermaking is disclosed as well as a process for their manufacture, a method for their use and a paper sheet containing the addition.. The additives can be used in paper manufacture as agents for improving retention, paper machine operation and the strength properties of the product. The additives are manufactured from the biomass that is a by-product of microbiological production of citric acid by a fermentation process using Aspergillus Niger, suitable by-product from other microbiological process, or from a biomass specifically produced for this purpose. The biomass that contains acetyl amino groups or other amides is chemically modified by hydrolysis of the amides to form primary amino groups . Under neutral or acidic conditions these primary amines become cationic, whi ch assures a good absorption of the additive onto fibres and fines of pulp that is generally of anionic nature. Furthermore, primary amino groups can form chemical bonds with carbonyl groups, and ionic interactions with carboxyl groups. Both these groups are abundant in the fibres and fines of pulps, especially in mechanical pulps. The additive prepared in this manner might contain glucosamine polymers that might be chemically bound to a carbohydrat e polymer or oligomer. Novel papermaking additives produced in this manner are particularly suitable for the production of paper from fibrous pulp suspensions produced at least partially from mechanical pulps, the high negative charge of which tends to overwhelm a majority of conventional cationic polymers.