Surface Functionalized Fillers for Highest Filler Levels

摘要

Traditionally, inorganic minerals are used as fillers in the papermaking process for cost saving reasons, to improve the optical properties, such as brightness and opacity, to improve the smoothness of the paper sheet surface, to give a less porous base paper for coating (improved "hold-out"), to improve the sheet formation by filling voids inside the fiber matrix, to enhance printability in various printing processes due to more uniform paper surface and better surface appearance as well as better ink receptivity (reduced ink penetration and strike-through), and to improve the dimensional stability. In addition, a range of specialty functional mineral fillers are used in order to achieve specific paper properties. Fillers can, however, also have undesirable effects on the final paper product, mainly related to the loss of bonding between fibers. This will lead to phenomena such as dusting and linting, and general weakness of the sheet during handling, further coating, calendering etc. Therefore, the use of fillers in a paper sheet has been practically limited (Fig. 1).