Metered Size Press Coated Mechanical Papers-A Comparison of Different Concepts, 2000 Metered Size Press Forum

Based on the experience that film coating misting is depending largely on coat weight it is proposed to split the coatweight for LWC into two portions. In the first part of the study different proportions of pre-and topcoat are compared both with a 10g/m2 single film coating and a 10 g/m2 blade coating at 5100 ft/min. Since the gloss and printed gloss development of the double-coated papers was insufficient in the second part the influence of an intermediate calendering after precoating was investigated. Intermediate calendering results in largely enhanced gloss and printed gloss without losses in brightness, opacity and strength. In the third part opacifying pigments were introduced into hte precoating formulation which further optimized the precoating. By this a paper could be produced that is superior with respect to opacity, brightness and gloss to the single coated cenchmarks. The misting tendency is greatly reduced compared to the single film press coating. The new technique thus gives enhanced freedom both with respect to base paper quality as to coating formulations to produce FCO at high machine speeds.