Process for the manufacture of paper and paperboard

US9631319B2 · kind B2 · utility

Assignee

• BASF SE

Inventor

• Christopher Alan Gray · Schifferstadt, DE

Key dates

• Filing date: Feb 25, 2013
• Grant date: Apr 25, 2017
• Expiry date: Jun 17, 2033

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D21H23/18
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

The present invention concerns a process of making paper, board or paperboard in which a cellulosic thin stock is provided and subjected to one or more shear stages and then drained on a moving screen to form a sheet which is dried, wherein the process employs a treatment system which is applied to the thin stock, said treatment system comprising as components, a) a cationic organic polymer of charge density of at least 3.0 meq/g with a molar mass Mw of up to 3 million Daltons or poly aluminum chloride (PAC), b) a cationic polymer having an average molar mass Mw of at least 500,000 Daltons and a charge density not exceeding 4.0 meq/g; c) a microparticulate material; in which components (b) and (c) are added to the cellulosic thin stock after the last shear stage before the head box and component (a) is added to the cellulosic thin stock before the said last shear stage.