Mineral oil migration from cardboard packaging into foodstuffs is recognized as a serious problem for the consumers. Within this study, a fast automated method for the determination of mineral oil permeation through barrier films was developed. The method is using 15 defined standard substances representing mineral oil chemistry instead of complex mineral oil mixtures. The developed method can be used for the evaluation of the barrier properties for polymer films regarding mineral oil components from paper and cardboard packaging materials. For all investigated permeants and polymer films, the logarithm of the permeation rates and the logarithm of the vapour pressure result in a linear correlation. The correlation can be used to compare the permeation properties of different barrier films. From the results of this study, it can be concluded that 12 mm oriented polyethylene terephthalate or 15 mm oriented polyamide are effective barriers towards mineral oil components. The barrier effect of pure polyolefin films is negligibly poor because the permeation is too fast and the lag time is in the range of a few hours at 40 C. As a consequence, the migration of mineral oil components from cardboard can be significantly reduced if inner layers of good barrier materials such as polyethylene terephthalate or polyamide are used.

Polymeric materials can be used as functional barriers to prevent contamination of food from the environment or from other packaging components, e.g. mineral oil hydrocarbons from printing inks. Polyethylene terephthalate (PET) is such a promising barrier material. From permeation studies found in the scientific literature lag times, diffusion coefficients or permeation rates towards organic chemicals could not derived because of the slow diffusion process of the permeants in PET. Knowledge about lag times or diffusion coefficients for different permeants, however, is essential for the evaluation of the barrier properties of PET films towards organic contaminants, e.g. mineral oil hydrocarbons.The aim of the study was to develop automated permeation testing method in order to determine the lag times of high-barrier films. From the lag times, the diffusion coefficients as well as the partition coefficients of the alkanes were calculated. In addition, the permeated amounts were simulated by use of diffusion models. Therefore, the lag times can be predicted under different experimental conditions as used in the current study. The results of this study show that the investigated 12 μm PET film is an effective barrier towards mineral oil hydrocarbons. For example, the predicted lag time for n-octane or n-dodecane at 40°C is 8.8 and 210 years respectively.

Polyethylene naphthalate (PEN) is a polyester polymer with well-known good barrier properties. PEN had been used in the food packaging area till 2012 especially as refillable bottles for soft drinks, juices, and beer. Now, PEN is mainly used in technical applications, e.g., for data storage tapes and organic light-emitting diode (OLED) applications. The aim of the study was the determination of the diffusion coefficients of organic molecules (n-alkanes, 1-alcohols) in PEN. Diffusion and partition coefficients were determined from the lag times of the permeation process of the permeants through a commercial 12 μm biaxial-oriented PEN film. In addition, activation energies of diffusion EA were calculated according to the Arrhenius approach. The activation energy of diffusion EA follows a correlation with the molecular volume V of the investigated permeants. In addition, the preexponential factor D0 follows a correlation with the activation energy of diffusion EA. The results of this study for PEN (e.g., EA, DP) were compared to literature data on PET.

Poly(ethylene terephthalate) (PET) is a highly inert packaging material that exhibits low interaction with foodstuff and consequently a limited diffusion of migrants. Migration modeling can therefore be used as an alternative to experimental migration tests in order to confirm compliance of PET packaging materials with food laws. The most important factor for predicting migration using mathematical models is the diffusion coefficient of the migrant in PET. However, current models that predict this parameter are typically based on worst-case scenarios and thereby significantly over-estimate the degree of migration. The key parameter for developing more realistic migration models is the activation energy of diffusion of potential migrants in PET, but experimental data on this are scarcely available in the scientific literature. The aim of the present study was therefore to develop a fast and precise method for determining diffusion coefficients and activation energies of diffusion of organic compounds in PET. Activation energies of diffusion for 13 organic compounds in PET were determined via their diffusion coefficient temperature dependencies. The molecular weight and activation energy of diffusion for the compounds investigated in this study were correlated, offering a basis for a new approach in predicting diffusion coefficients for use in migration modeling. The proposed method is a suitable tool to establish the datasets needed to refine the current migration model.

Poly(ethylene terephthalate) (PET) is a highly inert packaging material that exhibits low interaction with foodstuff and consequently a limited diffusion of migrants. Migration modeling can therefore be used as an alternative to experimental migration tests in order to confirm compliance of PET packaging materials with food laws. The most important factor for predicting migration using mathematical models is the diffusion coefficient of the migrant in PET. However, current models that predict this parameter are typically based on worst-case scenarios and thereby significantly over-estimate the degree of migration. The key parameter for developing more realistic migration models is the activation energy of diffusion of potential migrants in PET, but experimental data on this are scarcely available in the scientific literature. The aim of the present study was therefore to develop a fast and precise method for determining diffusion coefficients and activation energies of diffusion of organic compounds in PET. Activation energies of diffusion for 13 organic compounds in PET were determined via their diffusion coefficient temperature dependencies. The molecular weight and activation energy of diffusion for the compounds investigated in this study were correlated, offering a basis for a new approach in predicting diffusion coefficients for use in migration modeling. The proposed method is a suitable tool to establish the datasets needed to refine the current migration model