Investigation into the Runnability of Coating Colors at the Blade at High Production Speeds, 1996 Coating Conference Proceedings

The sustained trend of ever rising coating speeds is directed towards further productivity increases of modem coaters with large machine widths. However, the envisaged increased production speeds pose problems of many kinds irrespective of the original speed level to be enhanced. As far as blade coating is concerned, this objective frequently involves several different subtasks. Fortunately, existing restrictions in terms of web run, flying splice or drive control can be largely overcome by mechanical means. On the other hand the problems entailed in application and metering are far more complex in nature. High production speeds are often accompanied by more blade wear, streaking, skip coating and - most frequently -stalagmite formation or bleeding at the blade. This presentation focuses on findings of the working group ,,Stalagmite formation at the blade“ of the ZELLCHEMING Technical Committee for Coated Paper and Paperboard as well as on the results of the PI’S Research Project ,,impact of blade geometry and coating color rheology on bleeding at the blade and stalagmite formation at high coater speeds”. Stalagmite formation in particular is influenced by a multitude of parameters such as coating base, color formulation, solids content, water retention color