As in previous years, RUCO Druckfarben will be showing its colors at the glasstec trade fair in Düsseldorf, Germany, held Oct. 21-24, 2014 (Stand A30, Hall 12). Set to go on display for the first time is RUCO’s new ink series 935UV-LED, which the company has added to its proven range of products for the decoration of hollow and flat glass. 935UV-LED inks are suitable for LED curing and they can also be used with hybrid systems. This provides maximum flexibility for users.
 
In times of surging energy costs, it comes as no surprise that the glass decoration industry too is taking more and more interest in energy-efficient manufacturing techniques. The use of LED technology with screen printing inks is a promising option in this context. Based on its 935UV “flagship” series of screenprinting inks for glass decoration, RUCO is now also offering an LED UV-curing version.
 
In addition to being a potential cost-saving factor, these 935UV-LED inks also enable shorter production cycles and improved process security to be achieved, while offering the same benefits with regard to resistance characteristics, opacity and brilliance of colors. However, in contrast to conventional inks, which require subsequent post-curing of at least 24 hours, cross hatch testing can be carried out immediately after printing. Moreover, 935UV-LED inks offer advantages with regard to environmental and safety aspects.
 
Benefits of LED Technology Compared to Conventional UV-curing Systems
 
Conventional UV bulbs like those in mercury vapor lamps cure UV inks within the UV-C and UV-B spectrums, comprising wavelengths of 100–280 nanometers and 280–320 nanometers, respectively. By contrast, LED lamps have a narrow spectral output, most commonly at 365 or 395 nm with +/-20 nm at peak wavelength. LED-modified UV inks contain additional photoinitiators that have been tailored to react at these specific wavelengths. Thanks to this primarily chemical reaction in the long wavelength spectrum, LED systems can achieve excellent depth of cure, which results in better adhesion on the glass surface directly after the printing and curing process.
 
When using conventional UV-based systems, the glass will require a post-curing process, which means that users have to wait between 24 and 36 hours before they can check the adhesion of the ink film on the glass surface. With LED inks, this can be done immediately after curing.
 
Due to their good depth of cure, LED inks allow for greater layer thicknesses, which results in higher opacity. This is beneficial both for difficult substrates and for the application of difficult colors. When compared to ceramic inks, which must be exposed to high temperatures during the curing process before the final color can be seen, users can check the color accuracy of UV LED-based inks directly after curing.
 
Ink curing by means of LED is a new forward-looking technology. The use of light-emitting diodes offers a number of advantages compared with conventional systems, with lower energy consumption being one major factor. Moreover, LEDs do not create ozone, so that the need for expensive exhaust systems is eliminated, plus they have an extremely long service life.
 
The use and application of LED printing inks cannot and is not designed to completely replace the use of conventional UV printing inks and ceramic inks. However, in many cases, LED curable inks can provide a suitable alternative, bringing with them environmental benefits as well as new and unique decorating opportunities.
 
Meanwhile RUCO’s standard UV-curing 935UV inks are extremely popular among users and have proven their worth a million times over in many different fields. These two-component inks are suitable for multi-color inline printing and feature high resistance to chemical, alcoholic and cosmetic fill products as well as good dishwasher resistance. Curing under standard UV bulbs, these inks eliminate the need for thermal post-treatment in the form of time-consuming and expensive oven drying. This allows for more streamlined and cost-effective decoration processes.
 
From a visual point of view, inks of series 935UV open up an impressive variety of innovative design opportunities. In addition to the basic inks, which offer high opacity and brilliance of colors, there is also a wide range of special-effect inks available for achieving matt and frosted finishes as well as metallic and glitter effects, to name just a few. These inks are used, for instance, for decorating flat glass for gaming machines, furniture or shower doors, and also when it comes to hollow glassware for the cosmetic and other industries. Unlike ceramic printing inks, these UV inks can also be used for realizing special fancy embellishments using fluorescent and transparent colors as well as 4-color images – such opportunities are attractive especially for highly image-conscious segments such as advertising.
 
Moreover, series 935UV inks also offer a number of decisive advantages regarding user and environmental friendliness. Compared to ceramic and solvent-based inks, consumers are able to enjoy lead-free formulations as well as high chemical resistance. 935UV inks are free from heavy metals and comply with the limits specified by European standard EN 71, part 3. In addition, they meet the requirements laid down in the California Proposition 65, the most stringent environmental laws worldwide.
 
In addition to screen printing inks, RUCO will also be presenting its versatile T28 pad printing ink series at the glasstec trade fair. These glossy, physically drying and chemically reactive two-component inks are suitable for printing onto glass and metal and satisfy the demand for excellent mechanical and chemical resistance, as well as for high flexibility.