PROCESS FOR PRODUCING PAPER AND CARDBOARD

摘要

The invention relates to a process for producing paper and cardboard by dehydration of pulps, forming sheets and drying said sheets. Polyethylene imines of a molar mass Mw of greater than 500 000 or polymers containing vinyl amine units and having a molar mass of 5000 to 3 million are added to the pulps and subsequently, polymers containing cationic polyacrylic amides or vinyl amine units are added to said pulps, the molar masses Mw of the polymers being at least 4 million in each case. The pulp is then subjected to at least one shearing stage and flocculates by addition of bentonite, colloidal silicic acid or clay.