Eucalyptus Pulp Fibers with In-Situ Precipitated Calcium Carbonate – A 12-Inch Laboratory Paper Machine Study

Paper manufacturing on a global scale is a highly competitive market which requires to constantly improve the manufacturing process to be competitive. To decrease production cost paper manufactures, add filler material prior to sheet forming to replace costly wood fiber based raw material.

This research project investigates the use of in-situ precipitated calcium carbonate produced in the presence of eucalyptus fiber material at a 41.0% filler level prior to beating. The in-situ filler containing eucalyptus fiber suspension was used on a 12’ (304mm) wide Laboratory Fourdrinier Paper Machine together with non-filler containing eucalyptus fiber material, and a commercial precipitated calcium carbonate filler material.

The manufactured in-situ fiber suspension resulted in a higher ash retention compared to the addition of the powdered commercial PCC filler material. In addition to commercial filler material retention is improved at higher filler addition above 30%.

The increased ash retention is linked to the increased micro fibrillation fiber material of the in-situ filler-fiber suspension forming neckless like particles on the fibers microfibrils.

Mechanical paper properties showed an improvement for in-situ precipitated filler material compared to commercial filler material addition.

Optical properties could be improved in comparison to the eucalyptus fiber without filler addition for in-situ precipitated filler material and a combination of in-situ and commercial filler material.