Excimer technology for matting, cleaning and sterilization

Excimer technology is used to mat, clean, sterilize and modify surfaces. In a new excimer laboratory facility, customer-specific tests can be carried out to determine optimal parameters.

Short-wavelength excimer technology at 172nm is used in many industrial sectors and applications, for example for matting, bleaching or cleaning and modifying surfaces. Excimer stands for "excited dimer", which means that a dimer is excited to a higher energy state after an alternating voltage is applied. Excimer technology is used in the finishing of wood decorations and materials or in the matting of plastics. Since excimer lamps are cold light sources, heat-sensitive materials such as foils can also be treated.

IST Metz recently presented its new laboratory system with excimer technology at the UV Days. The system is used in the new Technology Campus, where customer-specific tests can be carried out to determine optimal parameters. Visitors can take part in live demonstrations of the excimer technology as well as a guided tour at the subsidiary eta plus, which manufactures the lamps in-house.

Excimer technology is used in many industrial sectors and applications to treat surfaces:

Matting: Irradiation of surface coatings with short-wave excimer emission leads to polymerization in the top layer of the coating. A thin hardened film forms on the surface. Since the polymerization also causes a shrinkage effect, the film near the surface exhibits micro-folds, resulting in a matte surface. Deep curing of the coating takes place downstream using conventional medium-pressure UV lamps. Major applications are PVC flooring, decorative films for the furniture and flooring industry, fiberboard and laminates, as well as wood panels and plastic parts in the automotive sector.

Bleaching & Disinfection: Ozone is formed at wavelengths below 242nm. Due to the 172nm wavelength and the associated high energy radiation, an excimer light source is an effective ozone generator. Ozone is used in the textile and pulp industry as a bleaching agent or, due to its virucidal, bactericidal and fungicidal effect, is also used in the disinfection of water and air. Damage to DNA occurs at wavelengths of up to 280nm, at which point bacteria and viruses can no longer multiply.

Cleaning and modification of surfaces: UV cleaning processes play an important role in the display and semiconductor industries. UV emission with a very short wavelength is used to break the bonds of organic substances. The additional generation of ozone oxidizes these contaminants to carbon dioxide and water. The result is a clean surface. Surface modification is used to improve surface tension for better wettability. Wettability is measured by the contact angle. A significant effect is achieved with wavelengths below 200nm. Typically excimer technology is used in display and touch panel manufacturing as well as wafer production.

At the new UV Technology Campus of IST Metz, customer-specific tests to determine optimum parameters can be carried out at the in-house laboratory facility with excimer technology. The plant, which is over three meters long, has three excimer units. A thin coating layer cures very quickly on the surface above the liquid substrate and contracts without affecting deeper layers of coating. Immediately subsequent final drying with UV or LED allows the finely folded state of the surface to be preserved. The result of matting with excimers is surfaces that have extremely high scratch and abrasion resistance, as well as high chemical resistance.

In addition, an infrared module can be used to preheat and adjust the paint viscosity. The maximum operating speed is 200 m/min. An acceleration section has been specially integrated for this purpose. Samples up to a material thickness of 50 mm can thus be processed reliably. Thanks to the extensive configuration, tests can be carried out for a wide range of industrial applications on a wide variety of substrates. (OM-09/23)