Survey “Highlighting LED UV”: Part 1 with BASF
The whole printing industry is talking about LED UV: Where do companies see the greatest potential in this regard? NarrowWebTech asked a range of companies who are active in the label industry what they think about LED UV and its current status quo in the market.
Conducted by Rosina Obermayer
Dr Juergen Baro
Technical Marketing Resins & Additives Europe for Printing & Packaging
1) What is the current market situation for LED UV and how will this further develop during the upcoming years?
Dr Juergen Baro: LED UV is penetrating all major printing technologies, but at a different pace. LED UV is state-of-the-art in inkjet and is also making major inroads into sheetfed offset with a focus on promotional printing in both cases. In label printing using flexo, LED UV is a late comer, where high press speeds in combination with corresponding food contact compliance requirements were difficult to achieve until now. However, significant technology progress in recent times concerning LED UV radiation sources and LED UV ink chemistry will make LED UV flexo a viable process option in label printing, in the future.
2) LED UV curing opens up potential for processing difficult substrates. What are the most promising applications with regard to narrow web production?
Dr Juergen Baro: Promising LED UV applications in the future will be flexo printing on thin plastic films usually sensitive to dimensional changes, where mercury lamps emit a considerable amount of heat often causing register problems resulting in a loss of print quality. LED UV radiation sources emit heat as well, but not in the direction of the substrate, so that they are categorized as “cool” radiation sources. LED UV flexo is considered to be the process of choice in narrow web growth markets like shrink sleeves, where dimensional stability of the substrate during printing is a prerequisite.
3) Ink migration is a hot topic: What are the challenges regarding printing inks and substrates? Compared with other ink systems, what do print shops have to consider if processing LED UV inks?
Dr Juergen Baro: LED UV flexo inks have a different formulation than conventional UV flexo inks mainly reflecting the different emission characteristics of LED UV radiation sources and mercury lamps. Proper surface cure is still a major obstacle for the LED UV process in general; as a consequence, guaranteeing low migration and with that, food contact compliance is still a considerable challenge. The very high reactivity of LED UV flexo inks to overcome these surface cure issues imparts higher daylight sensitivity, so that adequate handling of such LED UV flexo inks on and off press has to be ensured.
4) LED UV is often characterized as being sustainable: What ecological aspects do you identify such as recyclability of the printed and cured substrates?
Dr Juergen Baro: Sustainability is a controversial term missing a generally accepted definition. When looking at LED UV from a radiation source perspective, it has ecological advantages over mercury lamps such as lack of ozone formation during printing, savings in electric energy consumption and absence of environmentally critical mercury. However, when considering LED UV as a process, there will be no difference in recyclability for a radiation cured printed product, no matter if that is accomplished with an UV or an LED UV curing process, because the crosslinking mechanisms are very similar in both cases.