The role of base paper is commonly studied either in laboratory scale or with mill papers in pilot scale in dynamic conditions. The target of the study was to investigate the coating colour and liquid phase penetration into the model structures for metered size press, jet application and blade metering and spray coating in dynamic conditions. The coating of thin non-paper membranes containing different pore sizes showed that the coating colour penetrated totally and evenly through the big pores (3-5 μm) in metered size press coating due to the high pressure in the nip. Coating colour penetration was severe in jet application and blade metering and severe but random in spray coating. In metered size press coating, the liquid phase entered the small pores of the membrane despite the membrane's hydrophobic surface. The transport mechanism of the liquid phase in metered size press coating was mainly pressure penetration in the nip. In the case of jet application and blade metering and spray coating, the colour's liquid phase moved deeper into the hydrophilic than into the hydrophobic membrane for the same pore size. In these cases, the liquid phase was transported mainly by capillary absorption.
|Number of pages||6|
|Journal||Journal of Pulp and Paper Science|
|Publication status||Published - 1 Dec 2009|
|MoE publication type||Not Eligible|