Extrusion coating

Extrusion coating is the coating of a molten web of resin on to a substrate material. It is a versatile coating technique used for economic application of various plastics, notably polyethylene, onto board, paper, aluminium foils, cellulose or plastic films.

The actual process of extrusion coating involves extruding resin from a slot die at temperatures up to 320°C directly onto the moving web which is then passed through a nip consisting of a rubber covered pressure roller and a chrome plated cooling roll. The latter cools the molten film back into the solid state and also imparts the desired finish to the plastic surface. Variations of extrusion coating are "extrusion laminating" (which is the entirely same process, only that the extruded hot molten resin acts as the bonding medium to a second web of material), and co-extrusion (again the same process only with two or more extruders coupled to a single die head in which the individually extruded melts are brought together and finally extruded as a multi-layer film).

The market for extrusion coating includes a variety of end-use applications such as: Liquid Packaging, Photographic, Flexible Packaging, and Commercial Applications (including among others: Mill and Industrial Wrappings, Transport Packaging, Sack Linings, Building, Envelopes, Medical/Hygiene and Release Base).