Extrusion Coating Technology Reduces Edge Bead, Keeps Coat Weight Uniform
Nordson Extrusion Dies Industries has developed enhancements to extrusion coating dies and internal deckles that make it possible for converters to reduce edge bead with low melt strength polymers while maintaining coat weight uniformity. While standard internal deckles with edge profile control do a good job of reducing edge bead with the high melt strength resin LDPE, they have been less effective with linear polymers such as LLDPE and PP and with more expensive special-function copolymers such as ethylene-vinyl acetate (EVA), ethylene-acrylic acid (EAA), and ethylene-methyl acrylate (EMA). Trimming the larger beaded edges developed with these materials is a costly waste of material, since the combination of substrate and polymer coating cannot be reused. Research by Nordson Extrusion Dies Industries has led to development of a technology package that resolves the issue raised by low melt strength polymers. Components of the technology include: dies with lip lands that are substantially shorter than the industry standard; suite of secondary internal deckle blades, sized for various polymers; and smallest-diameter deckle rod in the industry. The “micro-rod” designed by Nordson Extrusion Dies Industries – half the standard diameter – permits less lateral movement of the melt and thus less edge bead formation. The suite of exchangeable secondary deckle blades with varying radii is available from the company on a custom-designed basis.
(440) 892-1580; www.nordson.com