GEW has launched its EXC Excimer UV lamp system. EXC uses dielectric barrier discharge (DBD) lamps to produce quasi-monochromatic vacuum ultraviolet radiation, typically at 172nm.
This radiation is commonly used for mattification of surface coatings where the elimination of matting agents can significantly improve stain resistance and durability of the final product. Gloss levels down to 2 GU can easily be achieved and the high efficiency lamps only require 5W/cm input power. Instant on/off switching enables customers to switch between high gloss (80 GU or higher) and matt finish products in seconds.
Other applications include modification of surface tension for improved adhesion, or surface cleaning for semiconductor and medical industries.
Robert Rae, managing director of sales at GEW, said: ‘GEW Excimer lamps can be produced in widths from 12cm up to 230cm and at up to 30mW/sq cm peak irradiance, the GEW system is one of the most powerful systems available worldwide. 222nm and 308nm variants are available and lamps can be custom-integrated to the customer’s specific application, including provision for all required nitrogen inerting and control. They can also be seamlessly integrated into the wider GEW UV systems which may be required for pre-gelling and post-cure, so that GEW can provide a turnkey curing or cleaning solution for any process.
‘Excimer technology for mattification eliminates the need for coatings to have additive mattifying agents. These agents, often mixed on site, can introduce significant variability and time to the coating process, which is completely eliminated with Excimer. In addition, the finished product is susceptible to “polishing” during further processing and often has poor physical and chemical durability. Again, Excimer coatings, with their 100 percent solid content, increase hardness, stain resistance and give preferable haptics (soft touch).
‘Further, pre-gelling the coatings with a UV LED lamp prior to excimer exposure allows for some control over the granularity and gloss level of the result, which gives additional process consistency and flexibility.’
It is imperative to use nitrogen inerting with mattifying Excimer systems to ensure homogenous irradiance and prevent the generation of excess ozone, according to the company. GEW has a long history of producing inert gas curing chambers for a wide variety of large-scale industrial applications, and its latest generation of inerting systems – controlled and monitored through GEW’s touchscreen control – have been developed to allow ‘easy access’ for webbing up and maintenance.