Process for producing paper and cardboard

US6132558A · kind A · utility

Assignee

• BASF SE

Inventors

• Rainer Dyllick-Brenzinger · Speyer, DE
• Hubert Meixner · Ludwigshafen, DE
• Friedrich Linhart · Heidelberg, DE
• Dietmar Monch · Weinheim, DE
• Klaus-Dieter Gerber · Ludwigshafen, DE
• Bernd Dirks · Heßheim, DE
• Peter G. Baumann · Stuttgart, DE

Key dates

• Filing date: Jan 8, 1999
• Grant date: Oct 17, 2000
• Expiry date: Jan 8, 2019

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D21H17/68
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

Paper and cardboard are produced by draining pulps, with sheet formation and drying of the sheets, by a process in which first PA0 (a) polyethyleneimines having a molar mass M.sub.w of more than 500,000 or polymers containing vinylamine units and having a molar mass of from 5000 to 3 million and then PA0 (b) cationic polyacrylamides or polymers containing vinylamine units, the molar masses M.sub.w of the polymers each being at least 4 million, are added to the pulps, and the pulp is then subjected to at least one shearing stage and is flocculated by adding bentonite, colloidal silica or clay.