Standard Bench Viscometry Methods for Aqueous Paper Coating Emulsions
Bench viscometry of paper coating emulsions requires standardized temperature control, verified spindle geometry, and multi-shear profiling to ensure runnability.
Coater Runnability
Operational Efficiency Metric
A process performance indicator quantifies the ability of a coating station to apply a functional layer to a web without causing breaks or defects. High levels of coater runnability ensure that a paper mill maintains high speed while achieving the desired surface finish. The property results from the interaction between the base paper strength and the fluid properties of the coating.
Blade Dynamics
Stable pressure at the nip prevents the formation of streaks that disrupt production. When the blade angle fluctuates, coater runnability decreases and leads to downtime for cleaning. Modern systems use automated controls to adjust these variables.
Web Break Mitigation
Structural integrity in the raw paper determines whether it can withstand the hydraulic force of the coating application. Slitter cracks and edge defects in the parent reel directly compromise coater runnability during the converting process. Strengthening the fiber bond in the base sheet provides the necessary resistance to moisture-induced weakening.
Mill operators monitor the frequency of stops per hundred reels to benchmark the efficiency of different fiber blends. Any increase in breakage often prompts a review of the refining energy or the starch application at the size press. High performance in this area reduces waste and ensures that the finished product meets the delivery schedule for the print customer.