The pulp grinding is one of the preparatory technical processes in paper manufacture . The mechanical modification of the cellulose fibers is understood as “grinding” the pulp . The fibers are shortened and / or roughened on their surface by loosening fibrils . These processes used to take place in the ramming mill of the paper mill , then in Dutch . Today the fibers are ground in refiners .
The interaction of the pulp with grinding sets of different geometries is intended to specifically influence the properties of the fibers and thus ultimately the properties of the paper. A distinction is made between different degrees of freeness, which have a decisive influence on the properties of the paper. The degree of grinding moves between two poles:
- crisp grinding: the fibers are shortened, but not changed in their other dimensions. The paper made from it becomes very absorbent, since a lot of water can be stored in the hollow fiber, but it does not stretch as much when moistened (e.g. hygiene paper).
- greasy grind: the fibers are squeezed and fibrillated. This allows more hydrogen bonds to form between the cellulose macromolecules . The paper works more strongly with fluctuations in humidity (e.g. greaseproof paper, baking paper) and requires greater internal tension during drying processes.
- Günter Krickler: The materials of the bookbinder . Schlueter, Hanover 1982.
- Meike Mentjes: Investigation of the drying behavior of paper when using drying techniques from paper restoration, construction and application of the Karibari drying panel. Siegl, Munich 2006.