New inert gas atmosphere UV curing system from GEW

The new hCP N2 inert atmosphere UV lamp head from Surrey-based GEW Ltd is optimized for inert atmosphere curing of silicon release coatings for food, cosmetic and pharmaceutical packaging applications, as well as self-adhesive label production.

The company said in a statement: ‘Conventional UV ink and coating chemistry can result in unacceptably high levels of odor and potential migration through incomplete cross-linking at the surface of the coating due to the presence of oxygen that inhibits cure. Migration from low molecular weight coating components is also a particularly significant problem as it may cause contamination and taint of the packaged product. 

‘Primarily recognized as being caused by non-reactive photoinitiators in the coating, odor and taint can be substantially reduced by the ability to reduce the photoinitiator concentration via inert atmosphere curing.  A side benefit in the up to 10 times reduction in photoinitiator concentration is a significant reduction in coating costs since this is an expensive component.  The hCP N2 offers a simple and effective solution to oxygen removal within the curing chamber.  Nitrogen gas is introduced into the lamp-head above the UV emitting lamp that, after having cooled the lamp, passes onto the substrate and out of the dryer assembly purging oxygen through small apertures.

‘A further benefit is a reduction in cooling air volume usage (especially important in air conditioned facilities) and the elimination of the requirement to vent and remove ozone due to the absence of oxygen in the curing environment.’

The web is supported on a water-cooled cylinder, maintaining an accurate web position (critical for inlet/outlet apertures) as well as controlling web temperature.  Each curing chamber has an oxygen concentration measurement module for precise control for minimal nitrogen consumption, both essential for product critical packaging.  A central PLC continuously monitors and records oxygen levels for quality auditing purposes and customer product validation.

The GEW hCP N2 system is available up to a maximum arc length of 100 cm (255 inches), lamp power up to 200 W/cm (500 W/in), average nitrogen consumption of 0.075 m3/hr/cm (1.06 ft3/hr/inch) and a minimum oxygen level of 200 ppm.