Low migration inks are specifically designed to not end up inside the food packaging or food. Plus, these inks support numerous other industries, including pharmaceuticals, cosmetics and more. By protecting the product, brands are protecting the consumer.
“Low migration inks should be used for labels and packaging where there is the potential for inks and coating to taint the product being labeled or packaged,” says Tom Hammer, head of technical marketing at Siegwerk. “This is especially true for food and pharmaceuticals, where the consumer does not want odor, taste or appearance to be altered by the package. Since low migration inks are formulated with higher molecular weight raw materials and chemistries that don’t bleed or migrate, the end product to the consumer will be unaffected.”
“With low migration inks, a lot of extra measures have been taken, especially with special raw materials, to minimize the migration of un-reacted species that risk ending up in the food and altering the taste and characteristics of the food stuff,” explains Henrik Bernquist, Flint Group’s product manager, EMEA and APAC, Narrow Web.
As ink technology continues to improve, demand has surged for these products – especially in Europe. “Today, low migration, UV curable inks are used widely across central Europe, and we feel the pull for these products expanding into all of Europe, the US, LATAM and Asia,” says Niklas Olsson, global brand manager at Flint Group. “This technology has grown exponentially and growth will continue. The demand comes from global brand owners as they extend their requirements in other regions, but it is also being gradually supported by local regulations.”
Bernquist adds that product knowledge and consumption of low migration ink systems continue to grow, with Europe being a driving force. Flint Group has seen a steady increase in low migration ink consumption, with significant growth each year.
According to Ed Dedman, flexo technical support manager at Zeller+Gmelin, “Our company manufactures UV flexo inks and coatings using the ‘FCM’ (food contact materials) designation, which will commonly be used as a reference for products intended for low migration applications outside of the Americas.”
The popularity of low migration inks, while growing, varies by region globally. “In North America, the primary ink chemistry used is water-based, although UV and LED systems are showing more interest,” says Hammer. “The demand for these UV LED inks are increasing but still not significant when compared to water-based or non-low migration UV LED usage. In recent years, EMEA UV and LED low migration systems are about 30% of sales, which is quite significant.”
Education abounds, too. No longer are ink suppliers and converters the only ones to get involved with the manufacture of safer products. Many brands are now requiring the use of low migration ink systems to further protect the consumer.
“Up until recently, most printers supplying labels and packaging used regular non-low migration inks and coatings, as the consumer product companies (CPC), for the most part, didn’t require low migration products,” explains Dedman. “In the last few years, more of those CPCs are asking for low migration products. I believe that’s a decision that helps them minimize any potential risk from even a remote possibility of migration in their packaging.”
While there are no pitfalls associated with using water-based or solvent low migration inks – when compared to non-migration products – there are several challenges worth noting. According to Hammer, UV LED systems come with the added challenges of cost, strength, adhesion and cure.
“Radiation curable chemistries that are required for low migration have polymeric photoinitiators that are significantly more expensive and somewhat less reactive than non-low migration chemistries,” explains Hammer. “In addition, these high molecular weight materials tend to be higher in viscosity as well, thus limiting how strong you can formulate an equivalent ink with printable flexo viscosities. When compared to standard UV LED inks, these low migration UV LED inks will not adhere as well to the packaging films used for foods due to the raw material limitations. Therefore, treated or topcoated films or primers might need to be used.”
Passing the test
Due to the inherent risks associated with inks migrating into the product, the ink systems must pass a wide array of guidelines and ordinances. In North America, inks must pass regulations instituted by the Food & Drug Administration (FDA), while global tests include Nestlé, Swiss Ordinance and more.
“These regulations provide positive and negative lists for raw materials that can be used, as well as migration limits for each,” states Siegwerk’s Hammer. “The ability to achieve low migration is not just the chemistry or formulation, but also manufacturing process. Ink manufacturers need to make sure manufacturing is done so there is no chance for contamination with non-low migration raw materials.”
Zeller+Gmelin’s Dedman notes that the testing requirements are quite stringent. “Low migration products are typically tested in an independent lab setting, and the specific requirements and/or regulations vary by market and intended use,” he says. “There are also a few major CPCs who have developed their own guidelines and require that all of their packaging meets those specifications. Most notable are companies like Nestlé, Hershey, Keurig, and many others.”
There is also an onus on the label converter to ensure that their products are as safe as possible. Printers must exhaust all avenues to ensure their presses are thoroughly cleaned before introducing low migration inks into an environment that traditionally utilize conventional chemistries. Both the inks and packaging are at risks of being contaminated upon first delivery, all the way through shipment of the final printed product.
“During the migration testing, as it is extremely sensitive for contamination, we strongly recommend to print products with low migration inks on a dedicated press,” states Flint Group’s Bernquist. “They should keep the inks, substrates and also the prints separated from other non-low migration products and prints.”
Printers must take a wide range of precautions, including logging the ink, ink batch, speed, humidity, printing and converting sequence and anilox type for each job.
“Printers also need to place more emphasis on proper drying and curing of inks versus press speeds when they need to achieve migration levels at parts per billion,” adds Hammer. “Careful attention for formulation, manufacturing and printing processes are all key to success.”
Zeller+Gmelin’s Dedman adds that the printer needs to follow Good Manufacturing Practices (GMP) within the pressroom and surrounding environments in order to minimize the danger of contamination with migratable components that can be found in cleaning materials, lubricants, fumes, dust and the like.
According to Hammer, Siegwerk has gone to great lengths to ensure its inks go far beyond the legal requirements, providing the ultimate in safety. “Our commitment is to be compliant beyond what is expected in North America, thus following European regulations as close as possible,” says Hammer. “Siegwerk also makes sure that our suppliers of raw material go through a strict testing and approval processes to ensure global compliance for the best possible control. All these processes guarantee the safety of our printing inks and enable the customer to manufacture a finished product that meets the legal requirements.”
Now more than ever, label printers have a wide selection of products from which to choose. Many suppliers have also joined forces to provide the best quality low migration solutions to the market. For example, Cyngient works through Sun Chemical for low migration ink products, having just launched a virtually odorless matte coating for beverage shrink sleeves.
Flint Group has engineered a wide range of low migration ink series, UV flexo inks, UV LED flexo inks, UV offset inks, UV screen whites and UV LED screen whites. All have been formulated for applications with low migration requirements. In addition to inks, Flint Group provides different varnishes, primers, adhesives and additives for these applications.
“Since the launch of our first low migration UV flexo ink series, Flexocure Ancora in 2012, we have upgraded it with the latest raw materials,” states Flint Group’s Bernquist. “Plus, we have developed a UV LED version and expanded the portfolio with additional low migration inks in UV offset and UV screen, and our latest UV flexo Flexocure Ancora 50 B3.”
In addition to its Flexocure Ancora line, Flint Group also offers EkoCure Ancora, a low migration UV LED flexo range of inks, and Lithocure Ancora, a low migration rotary offset range of inks for food label and packaging applications.
“Flint Group is continuously investing in technology and operations to support the market growth,” says Olsson. “To support the low migration trend, we increased our production capacity and are fully GMP accredited at both our Swedish and US manufacturing facilities. We have also invested in people to support the growth of our business around the world.”
Siegwerk offers a range of low migration flexographic inks, offset inks and overprint varnishes, including Sicura Flex 39-10 and Sicura Nutriflex LEDtec for flexographic applications, as well as Sicura Plast LM and Sicura NutriPlast LED for offset.
“Siegwerk has a full portfolio of water-based, UV, LED and solvent-based inks, coatings and adhesives that are low migration,” notes Siegwerk’s Hammer. “However, in the narrow web segment, it’s rare solvent chemistry is used. In North America, water-based inks are used primarily on narrow web presses, but there has been a growth in UV and LED curable technology for food packaging, especially. In EMEA, low migration inks are primarily UV or LED in the narrow web label market.”
Siegwerk continues to develop new chemistries to close the gaps between conventional chemistries. “Much attention has been placed on LED curing systems, and most recently we have introduced new products for flexo and offset, and we will continue to further research and develop products to further evolve,” says Hammer. “There is more emphasis in the market for UV and LED technology for many reasons, and Siegwerk will continue our focus here as well.”
In the North and South American markets, Zeller+Gmelin offers a UV flexo product line, the 30 Series, which contains a full range of commonly used colors (process, mixing bases and opaque whites), along with multiple coatings and adhesives.
For the European and Asia-Pacific markets, the company’s main manufacturing site in Germany – the Zeller+Gmelin headquarters – manufactures UV flexo inks and coatings utilizing the FCM designation.
“As a formulator of inks and coatings, in recent years, our available pool of raw materials for low migration products has increased dramatically,” states Zeller+Gmelin’s Dedman. “This has allowed us to formulate better products with even lower migratable content, and as many of the regulatory guidelines for low migration packaging have changed from year to year, these raw material options have allowed us to continue to meet those requirements. Ultimately, this assures our ability today to manufacture the safest possible inks and coatings for the consumer packaging market.”