UV/EB Materials
Since March 2008, Ultraviolet (UV) and Electron Beam (EB) ink, coating and adhesive formulations have been used in direct contact with food products. The change came about due to the efforts of the RadTech Food Packaging Alliance which was able to obtain FDA clearance for a number of UV/EB raw materials. This important FDA position allowed printers and converters to print, coat, and use adhesives on substrates where there is anticipated to be direct contact with some foods.
UV/EB materials in the form of printing inks, coatings, and adhesives have a relatively long successful history of applications in non-contact food packaging. The active word here is non-contact. It means that the UV/EB material being applied to food packaging must never have the prospect of migrating into the food product being packaged.
Functional Barriers
FDA regulations formerly required that an effective functional barrier to migration separate food products from UV/EB materials. Packaging materials such as paperboard, aluminum foil, and certain plastics baring migration of the applied UV/EB material has allowed applications on the outside of food packaging. Examples of successful permissible applications are found in external decoration on beer & beverage bottle/can packaging, on folding type cartons for a myriad of products including cereals, juices and frozen foods, pouches for dry and wet food products, and plastic containers for dairy products, etc.
While there is a history of growth in the application of UV and EB formulated inks, coatings and adhesives for food packaging, it has long been felt that growth would accelerate if direct food contact applications could be accomplished. In order for this to happen the FDA would have to offer clearance specific to UV/EB technology.
A History of UV/EB Coatings Entry
In 2005, RadTech, a trade organization dedicated to advancing UV/EB technology, took the initiative to assemble a group of interested members to form the RadTech Food Packaging Alliance. This group would work toward obtaining FDA clearance of UV/EB cured inks, coatings and adhesives formulated from acrylate raw material chemistry. The alliance consists of raw material suppliers, converters, packaging & equipment manufacturers, and formulators.
In March, 2008 the RadTech Food Packaging Alliance, after great effort, was able to announce the issuance of FDA Food Contact Notification (FCN) 772. This FDA clearance covers several formulating raw materials, “workhorse” acrylate monomers, an epoxy oligomer and a photoinitiator cured by UV or EB processes. Included is any mixture of one or more of the following:
- TPGDA – tripropylene glycol diacrylate
- TMPTA – trimethylolpropane triacrylate
- TMPEOTA – trimethylolpropane ethoxylate triacrylate
- Bisphenol A diglycidyl ether diacrylate
- Esacure One photoinitiator
Furthermore, the formulated products may be enhanced by the inclusion of other reactants, additives, pigments, polymers, etc., permitted by 21 CFR. Specifically the Food and Drug Administration (FDA) has approved Food Contact Notification (FCN 772) allowing the use of UV or EB energy cured formulations as coatings, or components of coatings, with both including inks for a variety of substrates, paper and paperboard, polymeric and metal, or as a component of adhesives.
Additionally, the migration level for each of the cleared monomers and photoinitiator in the cured coating, ink or adhesive is permitted to range up to 1 ppm. Further defined, the total level of nonvolatile extractables from the cured coating cannot be in excess of 1 ppm after correction for the migration level for each monomer and photoinitiator when used. Importantly, the resulting energy cured inks, coatings and adhesives can be used in direct contact with all Food Types under descriptions in 21 CFR of Conditions of Use A through H.
Formulators can combine FCN 772 raw materials with other already FDA cleared materials to provide a broader line-up of FDA compliant UV/EB inks, coatings and adhesives for food packaging without the need to obtain additional clearance from the FDA.
Higher Speeds with UV & EB Coatings
It’s well known that UV & EB energy curing technologies are attractive because they allow faster printing speeds as a result of instant cure (drying), coupled with an ability to provide adherence to a wide variety of substrates, including paper, plastics, glass, metals, etc. Additionally, UV & EB energy curing products feature attractive properties in terms of high gloss, excellent durability, chemical resistance, flexibility and light-fastness.
Now with this breakthrough allowing direct food contact applications to be exploited, food packaging end users are more aggressive pursuing the many significant pluses attributable to UV and EB cured inks, coatings and adhesives.
Included are the things that printers generally are looking for such as, inline capability, improved productivity, short run and high output capabilities, fast throughput, etc.
SAFE is a relative thing because we’ve often said UV/EB materials are all around the consumers of the world and they are being used without causing harm to us, but they go unnoticed as coatings on the flooring that we walk and play on, the spectacles’ and decorated “Tee’s” and “sweat” shirts that we wear, and the many different forms of packaging that we handle.
