In the digital printing area, UV curable inkjet inks are a perfect fit for printing on thick polymeric substrates as well as printing directly onto pre-shaped objects such as bottles, tubes, or cups. Especially in the label printing market, UV inkjet is quickly catching up with UV flexography printing in terms of market share and today’s piezo drop-on-demand technology can deliver print quality and output at eye level with UV flexography. The decision of which technology to pick depends on various factors like the average print run lengths, the operating speed, the type of substrate, and the level of personalisation, to name a few.

When it comes to personalisation/individualisation of prints, flexographic printing has the advantage that special optical effects such as metallics or matt varnishes are easily possible, which are still difficult to achieve in inkjet due to the sensitive printhead technology. Particularly matt varnishes are an important application as compared to most other types of printing technologies, UV curable inks offer an outstanding glossy appearance. A lot of applications benefit from this appearance but often also a more matt appearance is requested by brand owners. Therefore, in the UV flexographic market it is already a standard procedure to apply optical matt effect varnishes to reduce the glossiness of the inks if a less glossy application is required.

Hence, for Siegwerk there was an obvious market pull to create an industrial inkjet matt effect varnish which didn’t exist in the past and which would advance the inkjet technology further in the competition with the flexography technology. Siegwerk worked closely together with their raw material suppliers to search for new raw materials being able to create such an effect and which can be applied with today’s inkjet piezo printheads. Matt varnishes use ingredients with bigger particles to create an uneven surface leading to a diffuse reflection of light, which we perceive as a matt effect.

The particle sizes of common matt effect raw materials are too big to be used in standard inkjet inks as they would quickly lead to nozzle clogging of the printheads. Therefore, Siegwerk searched for raw materials with very fine particles which can still create an impressive matt effect. The intensive research and development phase was carried out in the Center of Excellence in Annemasse, France where Siegwerk manages inkjet production and innovation.

With the combination of big nozzle diameters and recirculation up to the nozzle plate, Seiko’s RC1536-L technology offers a perfect fit for printing this new matt effect varnish. The Matt Varnish worked immediately with the printheads of Seiko without any nozzle clogging or material compatibility issues.

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Today, Siegwerk offers a unique variety of high-quality UV inkjet solutions for all application areas in label and packaging printing, including standard and sensitive applications as well as primers and OPVs suitable for various scopes. With Sicura NutriJet the company for example provides an inkjet ink series for sensitive food and pharma packaging that works with different inkjet printing head technologies. Siegwerk’s portfolio covers both UV inkjet solutions for a wide range of applications including self-adhesive labels, wet-glue labels for beverages, direct printing on 3D-packaging objects or blister and aluminium lids for pharma and food products as well as customised water-based inkjet ink solutions for tissue printing and digital printing on flexible packaging. “As one of the leading providers of printing inks for labels and packaging applications for all kind of printing technologies, we don’t believe in ‘one fits all’ solutions as every application requires different ink characteristics”, adds Carni.

From standard CMYK inks for labels, through specialty inks for coding applications or custom-made spot colors to migration optimized inks for sensitive food and pharma packaging, Siegwerk always offers a suitable solution concretely adjusted to the final application and not only for a given printing equipment. For Siegwerk, customisation goes beyond classical colour matching, it also involves optimisation of adhesion, mechanical and chemical resistance properties as well as assessment of migration risks.

Siegwerk strongly believes that digital printing offers tremendous possibilities for growth in packaging. UV inkjet for example enables direct printing on 3D objects which not only opens new approaches for brand differentiation but also helps packaging producers to save labeling materials, reduce waste, and achieve overall leaner processes. By providing a combination of best-in-class ink performance, high product safety and continuous support and guidance, Siegwerk is always supporting its customers to address upcoming trends by meeting their individual needs with cutting-edge ink solutions.

Are you interested in learning more about Siegwerk's digital printing products? Or would you like to talk to a specialist about your application? Then please contact Siegwerk via Dr. Ralf Müller, Head of Sales UV Inkjet EMEA. E-mail: ralf.mueller2@siegwerk.com | www.siegwerk.com