When should aluminum foil be used as a functional barrier in a construction project what are the conditions that must be met from sdfbcx's blog

According to my understanding, the Food and Drug Administration (FDA) considers the addition of an aluminium foil containers layer to laminate materials to be a functional barrier. What is your opinion on whether or not the aluminium foil supplier layer should have a specific minimum thickness in order to be considered a functional barrier to printing ink? Alternatively, does the thickness of the  layer make a difference if the aluminum foil layer is laminated with PET layers on both sides of the  layer?

Despite the fact that a number of FDA's food additive regulations in Title 21 of the Code of Federal Regulations, such as 21 CFR 175.105 (Adhesives) and 21 CFR 177.1390 (Laminate structure for use at temperatures of 250 degrees Fahrenheit and above), do not define the term functional barrier, the FDA does not provide a definition for the term either. In accordance with Section 177.1390 of the Food and Drug Administration's regulations, aluminum foil is considered to be an effective barrier to the migration of materials used on the foil's non-food-contact side. However, the regulation does not specify a minimum thickness for the layer of aluminium foil manufacturer used.

Please understand that metallization (i. e., a very thin layer of vapor-deposited aluminum oxide on a film) is not the same as an aluminium foil layer in the traditional definition. Metallic plastic must perform as a self-contained functional barrier in order to be effective.

It is permissible to use the recycled layer as a dual-ovenable container for cooking food at 150 degrees Celsius for 30 minutes if the recycled layer has a thickness of less than 25 microns (0.001 inch) at room temperature or lower, and a thickness of less than 50 microns (0.002 inch) at higher temperatures, provided that only food containers are used in the feedstock to manufacture the recycled layer

Even though this guidance is provided in the context of recycled plastics, it suggests that the FDA believes that PET layers specifically meeting the thickness criteria above will serve as a functional barrier to prevent migration of substances from the nonfood-contact side when used under the conditions described above. Before considering whether a layer made of a different polymer than PET can be considered a functional barrier in the application of interest, it is necessary to evaluate each layer on an individual basis, either through testing or mathematical modeling, before determining whether it can be considered a functional barrier in the application of interest.