Effect of CMC and Soy Polymer Binder Systems on High Speed Blade Runnability, 1993 Coating Conference Proceedings

Blade runnability at high coater speeds has become one of the most critical issues in today’s LWC technology environment. This paper deals with the effect of coating formulation, in particular with the impact of CMC and chemically modified Soy Polymers as traditional co-binders, on the high-speed blade runnability of typical LWC offset coating formulation. A study performed on a pilot coater at speeds up to 1,700 m/min, has demonstrated significant differences in blade runnability between CMC / SB latex and Soy Polymer / SB latex systems. Under the conditions of this study, the CMC formulation experiences more severe blade bleeding even at the lower speed range (1,100 m/min). Photos of coating build-up on blade tip at increasing speeds, pertaining rheology and blade pressure data are discussed. Explanations are based on the theoretical concept of volume solids and VIMS (viscosity immobilization solids) and also on the fundamental differences between CMC and Soy Polymers with respect to their unlike chemical nature and especially to their different reaction mechanisms in a coating formulation.