States Malcolm Rae, Managing Director of GEW “Specific silicon release chemistries for self-adhesive label stock require a very low oxygen environment to achieve critical levels of adhesive cross linking. Traditionally, nitrogen inerted UV curing system were massive and consumed great amounts of costly nitrogen gas. Our challenge was to provide a compact and efficient inert curing system capable of processing heat sensitive, thin gauge films at a reasonable cost.”
Space restrictions had to be overcome on the converting line supplied by Polytype in order to integrate the UV unit. Using its state-of-the-art 3D CAD design system, GEW was able to engineer and manufacture a bespoke inert UV curing module with web transport features specifically for Anglian Flexible Packaging. Because the line was intended to coat unsupported films with a thickness as low as eight microns, the maximum in heat management was required. The inclusion of an integral watercooled chill roll was needed for both heat management and increased oxygen sealing. The NUVA Modified Atmosphere Curing System incorporates a UV curing lamp 51” (1300 mm) in length, rated to operate up to 400w/in (160 w/cm) and with a fully retractable lamp head allowing total access to all working parts for ease of maintenance and cleaning. The system is capable of lowering the oxygen level down to 6 ppm but typically operates in the range of 20 ppm at line speeds up to 500ff/min. (150 m/min). The nitrogen atmosphere operational functions are controlled through the GEW colour touch screen linked to an in-line oxygen analyser.
Comments Paul Field, Managing Director of Anglian Flexible Packaging, “The converting system containing the GEW UV system is truly multi-functional. It is capable of coating all unsupported filmic substrates along with metalized film, foils and paper. In addition to a silicon release coating, we can also apply pressure sensitive adhesives, hot melt coatings and apply laminates. GEW personnel worked closely with our people to ensure high quality production. The compact size of the GEW inerted system and low nitrogen consumption has resulted in significant cost savings.”
Concludes Mr. Rae, “In addition to offering the capability to UV cure free radical silicone coatings, the NUVA Modified Atmosphere Curing System also gives the converter the potential to print and cure inks and coating with substantially less photoinitiator levels. This is important in terms of ink and coating cost plus providing substantially lower odour levels and risk of coating migration. We are proud of our ability to meet the needs of Anglian Flexible Coatings and everyone here is committed to support the company in every way possible.”