Coating process for mfr. of CB-coated papers

摘要

In a process for the mfr. of paper having a CB coating on one side, the raw paper is passed through the gap between a coating roll (2) and an opposing roll (1). The CB coating material, which contains an encapsulated colour-forming substance, is continuously applied to the coating roll - at a thickness determined by a metering roll (14) and is applied by the coating roll to the paper. The coating and opposing rolls (2, 1) are pressed against one another in such a way that an average pressure of up to 2 N/mm<2> and a linear force of a max. of 80 N/m is exerted between them. Also claimed is a coating machine for the process in which the coating and opposing rolls are provided with a means of generating a linear force between them in the region of up to 80 kN/m. Pref. a max. press. of 1 N/mm<2> is exerted in the nip, and the linear force in the nip, which takes into account the hardness, the elasticity, the diameter, and the nature of the material of the roll covering, is selected to ensure a nip length in the direction of web travel of at least 5 mm, and more pref. 10-20 mm. The roll diameter and the properties of the covering meet the above requirements. One side of the press may be formed by a shoe press and belt. The pres is generated between the rolls by a variable force generator working against a counter-mechanism such as a spring or pressure cylinder.