On May 27, 2016 the Association of the European Adhesive & Sealant Industry (FEICA) published a guidance on migration testing of adhesives in non-plastic food contact materials (FCMs), providing specific guidelines for conformity testing of adhesives as components of FCMs. This guidance is part of a series on migration testing of non-plastic FCMs being developed by the packaging industry. In 2013, FEICA produced a guidance for a food contact status declaration for adhesives that discussed the selection of adhesives suitable for FCM applications (FPF reported).
Typically, less than 5% of the packaging is made of adhesives. While direct food contact is usually not intended, unintentional contact may occur at seams and edges, or via migration of volatiles through the packaging. Hence, “specific migration of individual compounds is of greater interest than overall migration, as the latter is only a measure if inertness and has no toxicological meaning,” the guidance argues.
The adhesives should not be tested as individual compounds, unless this is done for screening purposes; usually, testing of a finished FCM under real use conditions is preferred. Tests on the pure adhesive without substrate or the construction material may lead to an overestimation of migration into foodstuff, due to a lack of consideration given to several contributing factors. These include “curing times and conditions, interaction of adhesive with other FCM layers, barrier properties of other FCM layers, distribution of constituents within the FCM.”
Due to the complex chemistries and the breadth of potential FCM applications, the migration testing conditions need to be adapted for each group of adhesives in question. The FEICA guidance provides a description of the main types of adhesive systems used in FCMs, discusses material-specific properties relevant for defining specific testing conditions for each group, and provides remarks on the selection of test procedures and evaluation of test results. The covered groups of adhesives include reactive polyurethane (PU) adhesives, adhesives based on natural polymers, dispersions/emulsions (including adhesives based on vinyl acetate polymers (PVAc) or ethylene vinyl acetate (EVA) copolymers, and adhesives based on acrylic polymers and copolymers, including styrene acrylate terpolymers and reactive systems), cold seals, hot seals, and hotmelt adhesives.
Keller and Heckman LLP (June 21, 2016). “European guidance on migration testing of adhesives in non-plastic food-contact materials published.” The National Law Review
FEICA (May 27, 2016). “Migration testing of adhesives intended for food contact materials.” (pdf)