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Siegwerk has launched an ink range for gravure printing based on a polyurethane binder system and containing no polyvinyl chloride (PVC), matching the market trend towards reducing PVC use, ink complexity and set-up times, as well as allowing for quicker changeovers between print jobs.
Dr Hanns Martin Kaiser, head of technology, flexible packaging, EMEA at Siegwerk, explained: ‘Lately brand owners have expressed an increasing interest in PVC-free printing inks to realize complex packaging structures. Our new PUR-based ink system fulfills these requirements, while also incorporating other benefits.’
Initially available to the European market, the new ink technology is optimized to meet high performance requirements, such as high bond strength values in lamination. It allows for use in harsh retort conditions and can also be applied on modern barrier film substrates. Further, the PUR ink system is solely based on ethyl acetate as a solvent to allow utilization in monosolvent set-ups in combination with solvent recovery systems. Printers can also use common co-solvents like methyl ethyl ketone (MEK) or ethanol.
The key polyurethane binders are manufactured in Siegwerk’s own PUR production facilities in Annemasse, France and Bhiwadi, India.
Under industrial trial conditions the new PUR inks exhibited very good printability even at high printing speeds above 500 m/min. At the same time, it has been proved that the solvent retention level of the inks is very low.
‘After two years of development, the new ink range performed very successful in first extended industrial trials,’ said Kaiser. ‘It showed excellent printability with solid full tone and outstanding half tone reproduction. We optimized it for best dispersion results in order to produce high color strengths.’
Siegwerk’s PUR ink solution can also be used for medium performance applications, since it can be supplied in two different versions, either as a master base system in the form of readymade inks or as a master batch system, where the full PUR concentrates are combined with various master compounds (technical varnishes) out of one dispenser.
Combing a polyurethane binder with the masterbatch system creates a universal platform in terms of print performance, efficient handling in the ink room and cost-effectiveness, stated Siegwerk. The inks are tailored to the specific requirements of each customer to match their individual needs, keeping the portfolio simple and avoiding overdesign. This helps simplify ink room complexity and reduce ink stocks, which at the end improves cost-in-use for customers.
The new ink technology was developed in accordance with the relevant product safety standards. All ingredients are compliant with the stringent Swiss Ordinance and will also comply with the upcoming new German Ordinance.