Process for the manufacture of paper and paperboard

US9404223B2 · kind B2 · utility

Assignee

• BASF SE

Inventors

• Christopher Alan Gray · Schifferstadt, DE
• Antonius Moormann-Schmitz · Havelsee, DE
• Hubert Meixner · Ludwigshafen, DE
• Luis Miguel Sanchez Cerro · Heidelberg, DE
• Christian Jehn-Rendu · Orange, FR
• Thomas Muehlenbernd · Heidelberg, DE

Key dates

• Filing date: Jan 31, 2013
• Grant date: Aug 2, 2016
• Expiry date: Jan 31, 2033

Classification

• Technology area (CPC D): Textiles; Paper
• CPC primary: D21H23/26
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

The present invention relates to a process of making paper or paperboard in which a cellulosic thin stock is provided and subjected to one or more shear stages and then drained and a moving screen to form a sheet which is dried, wherein the process employs a retention system which is applied to the thin stock, said retention system comprising as components i) a blend of different cationic polymers and ii) a microparticulate material, in which the blend of cationic polymers comprises, a) a cationic polymer having a charge density of at least 3 mEq per gram and a molar mass of greater than 700,000 Da, b) a cationic polymer having a charge density of below 3 mEq per gram and an intrinsic viscosity of at least 3 dl/g, wherein one of the components of the retention system is dosed into the thin stock after the final shearing stage and the other is dosed into the thin stock before the final shearing stage.