Quality of High Deinked Pulp Content Magazine Paper Produced with Various Coating Methods, 1997 Coating Conference Proceedings

Base papers containing 0%, 20%, 40% and 60% deinked pulp (DIP) were coated at high speed with different coating heads in order to determine which type would provide the best coating quality. The coating systems used were a conventional short dwell, a sealing blade system, a nozzle applicator system with blade premetering and a film transfer system. The color used for coating was conventional offset and rotogravure formulations. Good quality coated magazine papers with a high content of deinked pulp can be produced with the right coating equipment. The film transfer unit is a good choice for offset papers. Evenness of the offset printed image appeared to be the best with the film coated paper. Also printed gloss and roughness values were almost as good as those obtained with blade coating methods. In all the studied coating systems, it was advantageous to have very high amounts of deinked pulp in the rotogravure papers in order to minimize the number of missing dots. Blade coaters gave better rotogravure printability than the film transfer coater. The best quality was achieved with the nozzle applicator with blade premetering. The disadvantage of the blade coating methods with deinked pulp containing papers were scratches caused by the impurities of base paper. The amount of scratches was increasing with higher DIP content and longer application dwell time. Cleaner DIP and tailored coating colors for different coating methods can reduce the scratch amount.