UV and EB are established core curing technologies – but are they completely safe for use on food packaging print?
The perfect recipe for radiation curing for food packaging has not yet been proposed or defined by the EU legislators. All that exists today are the GMP and Framework Regulation, as well as Swiss Ordinance, respected and now widely adopted across the food packaging supply chain, but still something less than the definitive answer. This situation was the driving force behind the Food Packaging Seminar held in Stuttgart in September by RadTech Europe, the regional association promoting the radiation curing technologies across all markets. The event drew together around 90 participants – all experienced specialists from the various disciplines related to the food packaging value chain (raw materials, printing inks, equipment, materials, and brand owners) -- to discuss and debate the proper use of radiation curing in food-safe printing, with the aim of enabling this technology -- which delivers a broad platform of benefits -- to achieve its well-deserved maximum potential.
Stephen Harrod, author of many specialist market reports for Smithers Pira on aspects of packaging and print, set the scene with an overview of the global packaging market and its current ‘megatrends’. He forecast 2014 growth in the revived global economy at ±3.5%, and annual global growth to 2018 at 4%. Food packaging – a €55 billion market in 2013 – will, he said, show 2.1% real annual growth to 2018, led by the meat, fish and poultry; chilled foods (including ready meals); and fresh food and vegetable sectors. UV curing, in this dynamic environment, has much to offer: good environmental credentials (no VOCs or solvents); fast turnaround; and high performance. Barriers to its use are currently cost – in terms of inks, varnishes, and energy usage; perceived lack of ease of use; heat from standard UV lamps; healthcare ‘scares’ involving migration of print through the packaging substrate; and recycling challenges.
Summarising, Mr Harrod drew attention to the strong growth in inkjet print. UV inkjet is already enjoying a CAGR of 14.8%, and there are considerable and continuing refinements in the technology base – printheads, inks, curing systems, android integrations, and presses. ‘Packaging is a great opportunity’, said Mr Harrod, for this versatile print technology.
The applied chemistries
Francis Bergiers, technical service and development specialist at Allnex, then provided a comprehensive overview of the applied chemistries involved in printing and packaging. The partner UV and EB curing inks must deliver viscosity, pigment wetting, cure speed, adhesion, flexibility, scratch resistance; and resistance to chemicals such as solvents. For food packaging print, additional requirements are low odour, no taste transfer, and low migration. All this must come, he underlined, at an acceptable price. Mr Bergiers highlighted recent innovations with particular relevance for food packaging, such as self-curing acrylates; acrylates that deliver higher purity; acrylates with an improved compromise between high molecular weight and viscosity; and the ability to achieve higher acrylate functionality whilst using lower viscosity systems.
‘Think like a food company!’
With the technology base clearly explained, it was time to hear from the customer: Dr Stephen Klump, Global Head of Packaging Quality and Safety, for Nestlé. His subject was ‘Managing Risk’. He outlined the many risks associated with the many different materials which come into contact with food items. Conveyor belts, plastic moulds, pipes and hoses are among the risks involved in food processing; and packaging materials – paper, board, plastic, metal, glass, coatings, inks, and adhesives -- are risks to finished or semi-finished products, as are a host of auxiliary items, such as straws, ice cream sticks, drinks dispensers.
Dr Klump said that ‘consumers are very aware that there are problems out there with their food’ – highlighting the recent horsemeat scandal, and reminding participants that governmental, NGO, and media coverage means that the consumer focus ‘goes viral’. In such a complex supply chain, involving many specialist suppliers of chemicals and raw materials as well as converters, packers, brand owners, and retailers, a publicly- identified safety problem can have serious consequences for a brand. Nestlé’s outstanding and continuing commitment to mitigating such brand risk through its packaging safety and compliance programme is long-established and proven, and Dr Klump adjured the assembled seminar participants to join him and ‘think like a food company’.
The Nestlé CoC
Suppliers across the value chain do not always deliver what they promise. If there is a problem, he said, it is the supplier’s responsibility to ‘find out before someone else finds out for you’. He listed the problems his company has experienced in the packaging arena since 1991 – a list which, of course, includes mineral oils, BPA and ITX, and odour issues. He detailed an agenda through which suppliers can ensure that they perform to the standards of the Nestlé certificate of compliance, in parallel with EU and FDA regulations and directives. All the CoC’s requirements are clearly and transparently communicated to the supplier base, and all are regularly updated.
Testing and legislation
The next seminar session focussed on the current status of legislation and testing, and the opportunities and threats they represent. Dr Andreas Grabitz, technical and legal expert at Eurofins Consumer Product Testing, presented two scholarly and instructive papers: the first on the principles and specialities of analytical testing of UV inks and coatings in a variety of situations; and the second on the extant diverse legal requirements relating to food packaging from a safety viewpoint, including detail on the Swiss and upcoming German Ordinances.
European Printing Inks Association’s viewpoint
Putting the science into action was the topic addressed, appropriately, by the Chairman of the European Printing Inks Association’s Energy Curing Work Group, Nick Ivory, who is also Technical Director of Sun Chemical. EuPIA is actively supporting the ongoing use of energy curing products in food packaging print. In this regard, he welcomed the work being done by various acrylate and photoinitiator suppliers on Dossiers for submission under the Swiss and German Ordinances, a move that will help establish more lenient migration limits for common photoinitiators and acrylates. This initiative is supported by EuPIA by supplying migration data. After detailing all the practical concerns and issues, he expressed the difficulties the industry has in pinpointing the correct way forward in the imprecise legal framework. ‘In the absence of recognised EU legislation’, he remarked, ‘it’s a bit like global warming!’ He concluded, however, that energy-curing products CAN safely be used in food packaging scenarios as long as their suitability is fully assessed.
Low-migration inkjet inks
Dr Marc Graindourze of Agfa Graphics focussed on low-migration inkjet ink technology for printing food packaging which, he said, is offering a whole new raft of possibilities for today’s brand owners, and is also environmentally friendly. Opportunities include mass customisation, just-in-time printing, promotions, and variable data printing – all using a print technology that is versatile, fast, reliable, and whose setup can be customised for specific applications. Agfa Graphics’ low-migration ink technology is delivering a printed result that is ‘testing positive’ for eliminating migration and set-off in a variety of food and pharmaceutical packaging applications and is a solution for direct print on to a packaging substrate – a coming solution, he said, because adding a label to packaging involves three steps, whereas direct print takes just one. The new Agfa Graphics inks will, Dr Graindourze concluded, constitute an element in an integrated system involving partnership along the supply chain.
The carton industry speaks
BPIF Cartons’ Technical Director, John Wilson, who is also Product and Applications Manager at Sun Chemical, completed the formal programme with a view from the mainstream packaging industry on the safe use of radiation curing. Printers in the food packaging arena choosing to take the radiation-cured low-migration inks route are facing a number of new challenges – and many questions for which they need answers both from their brand owner/retailer and their own suppliers. The BPIF are actively supporting their members with the creation of a low migration questionnaire which they can use with their suppliers as a discussion document, creating a technical focus at meetings, and exploring the new ‘barrier boards’ that the board mills are now introducing to the market. Mr Wilson admitted that BPIF Cartons are also closely following the Nestlé and EuPIA guidelines – proof that, in an industry sector where there is still no legislative clarity, the supply chain is taking the initiative and creating its own consensus.
General Secretary Mark Macaré concluded that the RadTech Europe seminar ‘brought the industry closer to achieving full clearance for UV/EB curing in the food packaging segment.’