IN Brief:
- Domino has expanded its MEK-free low-VOC ink portfolio for Ax-Series continuous inkjet coders.
- The company identifies formulations 1BK112, 7BK107 and 7CL103 for differing adhesion, resistance and packaging requirements.
- Food packaging suitability depends on material compatibility and final migration testing; solvent consumption claims are conditional.
Domino Printing Sciences has expanded its range of methyl ethyl ketone-free inks for Ax-Series continuous inkjet printers, targeting manufacturers that need durable product coding with reduced reliance on conventional solvent formulations. The range includes products suitable for different food packaging substrates and operating environments, with claimed drying performance close to traditional MEK-based inks. The new formulations extend the available consumables for existing Ax-Series technology, including the recently introduced Ax560i printer.
Continuous inkjet systems direct charged droplets to form codes on packs moving along a production line. The ink must remain stable inside the printer but dry rapidly after deposition, making the interaction of solvents, colourants and resins critical to both reliability and adhesion. MEK has commonly been used to achieve fast drying; replacing it can change the behaviour of a printed mark on films, glass or metal. Codes deposited onto a fast-moving pack may be exposed almost immediately to conveyor contact, condensation or cold storage. Inadequate drying or adhesion can make an otherwise correctly printed batch or date code illegible before dispatch.
Domino’s expanded portfolio includes 1BK112, a general purpose black ink for metal, glass and certain plastics; 7CL103, a clear fluorescent formulation designed for resistance to retort processing and alcohol; and 7BK107, a black ink developed for more demanding applications involving oils, alcohol and food packaging surfaces. Each formulation addresses a different combination of substrate and resistance requirements. Domino supplied MEK-free consumables before this expansion, but the additional products widen the choice available for individual coding conditions.
Domino says the newer inks use alternative pentanone-based solvents to approach the drying times associated with MEK. It reports field trials in manufacturing applications, including 1BK112 on freezer-grade flow-wrap packaging. Results obtained on freezer-grade flow wrap do not establish performance on untreated films or wet containers. Substrate treatment, condensation, print distance and conveyor speed can change adhesion and drying, while handling after printing may abrade the deposited mark. Qualification therefore requires the actual packaging substrate and the conditions that will apply after printing, not simply a comparison of laboratory drying times.
Food packaging requires another distinction between a legible code and a compliant printed pack. Domino describes formulations intended for direct and indirect food packaging applications, including products designed with the German Printing Ink Ordinance in mind. Their suitability depends on the final printed structure and intended use. Migration testing considers whether substances could move into food under relevant contact conditions, taking account of ink coverage, substrate, barrier properties and process history. Migration testing must therefore assess the completed pack under its intended food contact conditions; a code printed on the outside of a barrier material cannot be assessed in the same way as ink with potential direct food contact.
Reducing MEK usage is also relevant to solvent handling, replenishment and local environmental reporting obligations. Domino says its MEK-free solutions can cut make-up consumption by up to 35% compared with conventional alternatives, with reductions reaching 50% when certain Ax-Series printers are fitted with the Green Pack solvent recovery add-on. The figures come from the supplier and depend on operating conditions and compatible equipment. The 35% and 50% figures represent separate equipment configurations, not cumulative savings.
The Green Pack arrangement recovers condensed solvent for reuse, and Domino says additional recovery functions are available on the Ax560i. Its CleanAssist system also automates parts of printhead cleaning using recycled make-up fluid. Solvent consumption therefore needs to be assessed across printing, cleaning, evaporation and maintenance rather than attributed entirely to the ink deposited on each pack. At a factory, fewer solvent additions would need to be weighed against line uptime, code quality and the cost of qualified replacement consumables.
Changes to packaging films or line speed can alter code legibility even when a previously qualified ink remains in use. A packaging trial should therefore cover the intended printhead setup, coding distance, handling sequence and cleaning or restart conditions. The accepted code must remain readable throughout the product’s planned distribution and storage cycle, including freezing or wet handling where relevant.
Food producers increasingly print variable traceability information onto a wider assortment of films, bottles and coated packs. The expanded ink range gives plants more options, but a formulation that adheres to one material cannot be assumed to perform after freezing, wet handling or heat treatment on another. Domino has not supplied an independent performance comparison across every substrate or measured emissions reductions at a named food plant. Its stated savings can be tested against each factory’s baseline consumption while adhesion, legibility and packaging migration requirements are checked on the actual production materials.
