How to Produce Different Surface Structures for LWC Matt Paper Grade for CSWO Printing with Existing On-line Equipment

摘要

LWC matt paper grades for coldset web offset offer the biggest quality achievement potential since the introduction of 4-colour printing in CSWO printing industry. In order to fully benefit the business potential of Matt LWC paper grades, lot of work is required in various areas; optimization of production lines of these paper grades, optimization of quality of the sheet for CSWO printing, optimization of printing process to print coated grades and optimization of the end-use concept. This presentation deals with the first two areas: optimization of production technology and optimization of the quality of the product. Commercial base papers, produced with different production technology and raw materials, are coated in pilot conditions and then further printed in commercial conditions. The Confocal Raman technology is used for identifying the binder concentration in both lateral and z-direction of the coated paper samples. Confocal Raman microscopy is further used for the identification of the ink pigment compounds in the paper surface. With the analyses performed it can be shown that base paper structure has influence on the composition of the coating structure, when using metering size press coating application. This study shows as well, that latex coverage of the paper surface has influence on the build-up tendency of LWC matt papers in satellite type CSWO printing press. This study shows as well evidence, that ink pigments used in CSWO printing do penetrate through the whole coating layer all the way to the base sheet surface.