A wide variety of adhesives can be used to manufacture multilayer food packaging materials. Since these materials are usually in direct contact with the packed food, compounds from the adhesive may migrate into it. Therefore it is important to determine the composition of the adhesives used. The main aims of this work were to determine the compounds present in the adhesives used in the food packaging, to study their migration to food simulants and finally to use these data to test a mathematical tool designed for predicting migration to food from laminates containing adhesives. For this purpose a total of 45 market samples of multilayer materials (laminates and other glued materials) produced with 29 different adhesives were studied. A total of 55 different compounds were detected in these adhesives, 57% of these compounds migrated into a dry food simulant (Tenax®) through the food contact layer. These data were also used to compare it with the theoretically estimated migration of the adhesive compounds using “upper-bound reference” values for the diffusion and partition coefficients implied in a multilayer migration model. In 93% of the cases the estimated migration results met or exceeded the experimental ones. This is an important requirement for testing the applicability of these theoretical migration estimations for compliance decisions which aim to protect the consumer's health.

Partition and diffusion coefficients of volatile compounds in polymers have been broadly studied in the literature in order to provide the tools necessary to predict migration from the packaging materials to the food using the appropriate mathematical models. But often, food packaging materials are multilayer materials where several substrates are joint by adhesive layers. Little is known about the partition coefficients between adhesives and substrates used in these materials and about the diffusion coefficients in some of the materials commonly used such as paper or cardboard. All of these parameters will have a direct effect on the final migration of the compound. The objective of this work was to study the behaviour of the compounds found on the acrylic adhesives in 4 different real laminates. Partition coefficients between several types of acrylic adhesives and substrate materials (polyethylene, polypropylene, couche paper and kraft paper) were experimentally calculated. Moreover, diffusion coefficients of the compounds in these four materials were derived from experimental data. Finally, a migration test with Tenax was carried out. A wide variation of results for partition coefficients was found due to the difference on the chemical properties of the compounds studied. In fact, a relation between the coefficients and their Hildebrand solubility parameters was found. Moreover, the most relevant result found in the diffusion coefficient values was that the coefficients in paper were lower than in PE but higher than in PP. Migration results showed that only 4 out of 11 compounds were found in Tenax. Only 2,4,7,9-tetramethyldec-5-yne-4,7-diol belong to a high toxic class according to Cramer rules.