Food-safe packaging print remains a prime concern for product manufacturers and retailers, as well as for packaging suppliers and converters. It is a complex topic, involving, as it does, a broad regulatory base; a diverse array of packaging substrates; the many available choices of printing/imaging technologies; and the inks and varnishes that they employ in delivering on-pack branding and labeling. Their integrity must be retained at every level of the production and packaging chain—to ensure that the consumer can safely enjoy the product. 

RadTech Europe, the association promoting the advancement of radiation curing by UV, EB, and laser, has for several years been active in the food-safe packaging print arena. The association recently brought together a major tranche of the relevant value chain for an in-depth seminar—the ninth that RadTech Europe has organized—on the current and future use of UV and EB ink curing in this key packaging print market.  Over 70 participants including brand owners and representatives of the entire packaging supply chain came together in Frankfurt in October for this very focused event. 

RadTech Europe’s Secretary-General Mark Macaré welcomed participants for a day of presentations and networking, asking “What’s the trigger for today?” in terms of food packaging print. First to take the stand was Charles Bourrouse of Sartomer, part of Arkema Group, global suppliers of specialty acrylates and methacrylates.

He presented a broad overview of the applied chemistries inherent in printing and packaging materials, highlighting trends for new developments in low-migration inks. Today’s state-of-the-art radiation curing systems, he said, still represent a very small percentage of the total market, though lamp price reductions are encouraging uptake in both analog flexo and offset print. However, Mr. Bourrouse noted that a number of practical challenges still remain at every level of ink chemistry to ensure total elimination of set-off and migration, and he mapped out next steps and development opportunities.

Food packaging market data

Dominic Cakebread, packaging consultant for market researchers Smithers Pira, expanded on the topic of food packaging market usage of radiation curing. He said that food and beverage packaging together make up two-thirds of the consumer packaging market and continue to show robust growth globally.

He identified the current megatrends that are driving the packaging world.  Top of the list was lightweighting, which affects nearly all packaging materials.   Next came format substitution—particularly in relation to flexible pouches—and, of course, sustainability concerns. A 2016 Smithers Pira research survey indicates, he said, that 96% of brand owners consider sustainability to be important for their business. 

Delving into the profile of radiation curing by print process, he said its overall market share is forecast to grow at a healthy CAGR of 4.1% to 2019, with cartons and labels the largest markets. He highlighted the relevant key advantages of UV/EB curing: instant ink cure with minimal dot gain; a high-gloss, vibrant finish for the printed image; the ability to tailor cured ink to special requirements such as  chemical or abrasion resistance; and the environmental benefits—no VOCs or solvents, for example—along with the possibility of low-migration inks.

Nestlé: a leading brand owner’s perspective

With an overall brief to manage a multidisciplinary approach to food packaging safety within Nestlé’s extensive product portfolio, Dr. Amaury Patin of the company’s Swiss research center enlightened seminar participants on Nestlé’s perspective. With a €7 billion annual spend on packaging and 64,000 individual packaging specifications, the need for in-depth analysis and control of quality is, he said, paramount.

Dr. Patin and his team are currently researching a completely new approach to these testing procedures.  He explained the complex recipe ingredients that constitute packaging per se, He went on to show how migration can occur, both directly through the substrate to the contents, and via ink or varnish set-off from the printed packaging surface to the unprinted (food contact) side during pre-fill storage.

Nestlé is known for its dedication to consumer well-being, and in relation to printing inks maintains the standards of the Swiss Ordinance—currently the most comprehensive legislation—and the company’s own highly-regarded Guidance Note on Packaging Print, of which a new update has recently been published. Dr. Patin’s overarching message was that it is in the interests of all partners in the packaging value chain to have a full knowledge of the products they deliver.  He also urged suppliers to “think like a food company.”

Legal and compliance requirements

Rachida Semail, a Partner in Keller & Heckman, legal practitioners specializing in food law, summarized the scope and practical data requirements in the German and Swiss Ordinances, highlighted the differences between them in relation to printing inks, and explained the implications and ongoing complexities of implementation and compliance. She also examined other potentially relevant legal initiatives such as the draft EU BPA Regulation, providing a remarkable overview of an evolving legislative base complicated by supply-chain sectors that are unsurprisingly active in lobbying for their own special interests. 

This was a topic with implications for all seminar participants, and moderator Paul Kelly brought together Perrine Cahen of Allnex, Nick Ivory of Sun Chemical and EuPIA, Rachida Semail of Keller & Heckman, and Amaury Patin of Nestlé to debate the issues along with the audience. It was evident that the packaging print supply chain members are, indeed, very aware of the need to be proactive in meeting their respective responsibilities. Printing inks legislation, all agreed, can be useful, particularly in protecting the consumer. But, today’s legislative base is a maze, and there is currently little likelihood of establishing one complete, overarching international standard.  

Inks and varnishes 

EuPIA, the European Printing Inks Association, is a longtime promoter of good manufacturing practice (GMP) with inks, and is an active participant in guidance on their use on food contact materials. Nick Ivory, EuPIA chairman and technical director of Sun Chemical, provided a helpful update on the association’s positive contribution to the debate and to managing its outcome.  

EuPIA’s latest, highly-detailed GMP guidance document, published in March specifically for the ink industry, aims to assist in controlling food-safety hazards in the design and manufacture of inks, varnishes, and coatings to be used on food contact materials, both on the food-contact surfaces and non-food contact surfaces of such materials.

The stand-alone document is, said Ivory, “a road map for the process of continuous improvement” and makes provision for regular audits by brand owners and packaging converters, delivering a high level of transparency at all levels. All EuPIA members are expected to adopt it, and may additionally wish to comply with the more generic International Food Standard-accredited standards such as BRC IOP or ISO22002-4.

Low-migration inkjet inks

Dr. Marc Graindourze, business development manager for industrial inkjet inks at Agfa Graphics, expanded on the role of low-migration inkjet ink technology in indirect print applications on food packaging.  Here, he said, a safe imaging process involves “the combination and control of all parts of the print solution”: substrate, low-migration UV-curable inkjet ink, the printing and processing environments, and food storage and processing conditions.

He emphasized that “each application has its own very specific risks,” for example, print on aluminum blister packs, self-adhesive labels, sleeve labels, and direct-to-container print.  Dr. Graindourze explored the chemistry of creating low-migration UV-cured inks at low viscosity. Particularly with inkjet and flexo print, he said, this is a key element for success, and Agfa Graphics is currently working on a conceptual low-migration, low-viscosity inkjet ink design solution.

Carton makers’ agenda 

Pieter Geers of the Technical Committee of the European Carton Makers Association (ECMA) said that the Group’s Good Manufacturing Practice Guide underlines the plurality of the central carton packaging concept. As he reminded the audience, “If you are a printer, you are not making a generic product. Every print job is different.”

Outlining the wide array of “hard” and “soft” legislation that pertains to packaging, he went on to examine the many different practical elements in an item of packaging including afterlife uses and the combination of boards, adhesives, inks, and coatings that make up a finished carton.  He also showed how, in industry tests to the EN1186-13 standard, the ink migration factor differs by carton substrate type—even between virgin and recycled pulp content.    

He said that in the production environment it is essential to control all physical hazards such as the ingress of drawing pins, glass shards, insects, etc., as well as the chemical hazards of inks and such factors as machine operators’ perfumes.

Optimizing the print process

Optimizing the safe usage of UV-cured inks on food packaging, with particular reference to UV flexo was the topic addressed by Werner Veit from the R&D department of Constantia Teich. He examined the benefits and limitations of UV flexo as a print process and identified the variety of packaging substrates that employ it, from lacquered aluminum for dairy, pharmaceutical, and pet food applications to PET and PET/paper/PET lidding laminates, paper/aluminum/PET for soup pouches, and plain paper banderoles.

Veit went on to detail the optimization of the UV flexo process to achieve the desired results. His exploration included a “worst case” investigation as well as a pressroom testing and maintenance routine to ensure process reliability and compliance in food packaging conversion. 

The RadTech Europe Conference and Exhibition 2017 in Prague next October 17-19 will address the full agenda of radiation curing and its diverse markets.