PROCESS FOR THE MANUFACTURE OF PAPER AND PAPERBOARD

• Main Authors: JEHN-RENDU, CHRISTIAN, SANCHEZ CERRO, LUIS MIGUEL, MEIXNER, HUBERT, MÜHLENBERND, THOMAS, MOORMANN-SCHMITZ, ANTONIUS, GRAY, CHRISTOPHER ALAN
• Format: Patent
• Language: English; Polish
• Published: 31.07.2019
• Subjects: IMPREGNATING OR COATING OF PAPER; PAPER NOT OTHERWISE PROVIDED FOR; PAPER-MAKING; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; PRODUCTION OF CELLULOSE; PULP COMPOSITIONS; TEXTILES; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G

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.