Company claims UV technology eliminates ink migration
odours and ink migration in food packaging, its manufacturer
claims.
Italy-based Gidue said its UV Time! label printer technology is based on the principle of polymerisation under nitrogen inert atmosphere. Gidue claims the flexo technology differs from similar solutions that pump the oxygen out of the web printer by substituting it with nitrogen. UV Time! is designed to create a nitrogen 'blade' to break the boundary layer of air transported by the web, reating a very thin bed of inert atmosphere on the substrate to be printed. The inert atmosphere prevents the UV-radiated photo-initiators, which are responsible for ink polymerisation, from creating unwanted radical combinations with the oxygen particles carried by the web, the company claimed. The device allows the target oxygen presence that allows the elimination of odours and ink migration - between 50 parts per million (ppm) and 30ppm - to be reached with a minimal consumption of nitrogen. Food packagers can also use UV inks with a lower quantity of expensive photo-initiators in their formulation to improve the curing process accuracy and speed. "This reduction counterbalances the cost of nitrogen consumption and makes the UV Time! system, the first really cost-efficient UV curing process," the company claimed. Ink migration can be controlled and volatile organic compound (VOC) elimination increased due to the reduced layer of air transported by the substrate, the company claimed. "Thanks to a 'deeper' and faster curing, heavier layers of ink can be laid on the substrate increasing the opacity effects, ink chemical and scratch resistance, and reducing the thermal stress on the printed material," Gidue stated. Less powerful lamps are needed for the process, reducing the amount of energy used in UV label printing, the company claimed. The company has designed UV Time ! to fit in Gidue's flexo machines range with some retrofitting. The company is also offering UV Time coupled to its Athena flexo press in widths from 530mm to 730mm. The UV curing system is made up of two gas chambers placed to the right and left of the UV lamp. The nitrogen flows into the UV reaction zone under the lamp from an injection pipe directly connected to an outdoor gas disposal system from Air Liquide. The nitrogen flow is controled by an operating panel near the printing machine. UV processes for curing ink on packing has caused food safety problems in the past. In 2005 Italy's food safety regulators detected the curing chemical ITX in some batches of the Nestlé milk products, sparking a massive recall. The curing agent was found to have migrated through the packaging and into the milk. The packaging was produced by Sweden-based Tetra Pak. Tetra Pak then stopped using ITX in the packing for the affected Nestlé products after being informed of the problem and switch to inks that did not require UV curing.
