Citation
(2007), "Advantages of slot die coating over roll coating are now more accessible", Pigment & Resin Technology, Vol. 36 No. 4. https://doi.org/10.1108/prt.2007.12936dab.025
Publisher
:Emerald Group Publishing Limited
Copyright © 2007, Emerald Group Publishing Limited
Advantages of slot die coating over roll coating are now more accessible
Advantages of slot die coating over roll coating are now more accessible
Slot die systems are used for applying fluids or polymers such as adhesives, inks, electrolytes, and magnetic slurries onto continuous-web substrates used in packaging, electronic displays, window glazing, automotive windshields, flexible batteries, medical patches and liners, label stock, and many other products.
In roll coating, the amount of material deposited on the substrate is controlled indirectly by means of wiping blades or pre-set gaps between rollers; any excess coating material is scraped away and returned to the coating bath; and the bath itself is open to the workplace environment. Slot dies, on the other hand, are closed systems, and the amount of coating material is pre- metered by means of a precision pump. As a result, slot die coating provides these advantages:
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more consistent coat weight and cross-web distribution;
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higher line speeds; and
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minimization of volatile emissions, coating contamination, raw material waste, and workplace messiness.
“While Liberty Coating Equipment did market internationally, EDI will expand global access to Liberty technology through its extensive worldwide sales and service network,” Curtin said. “We also will draw on our ongoing research to extend the applicability of slot die systems and make them even more predictable. Current slot-die innovations at EDI include computer simulation of coating application, technologies that make it easier to vary width and thickness, and development of `drop-in' modular coating systems.”
A Liberty coating system typically includes a slot die, positioning support, and fluid-delivery pump. While the lips of the die are integral with the die bodies and thus fixed, operators can vary product thickness and width by means of shims that change the dimensions of the slot gap. Also available are “cascade” dies with multiple slots that make possible multilayer coatings. Liberty's WetWare system combines die, positioner, pump, and ancillary components into a module that can be shipped to a customer or prospect for on-site slot-die coating trials on actual production lines.