Migration Prevention
Protective coating or film applied to paperboard packaging prevents the migration of unwanted chemicals from the recycled board into the packaged foodstuff. This functional barrier layer must block volatile substances, such as mineral oil saturated hydrocarbons, from passing through to the product. It ensures that recycled paperboard can be used safely for dry food packaging.
This barrier remains effective over the entire shelf life of the food.
Material Composition
Thickness and chemical composition of the barrier determine its effectiveness against different classes of migrating molecules. Common barrier materials include thin layers of aluminum, specialized polymers like ethylene vinyl alcohol, or water-based barrier coatings. These materials create a tight molecular mesh that blocks the passage of volatile organic compounds.
Laboratory tests measure this resistance by exposing the barrier to specific chemical surrogates.
Safety Verification
Deployment of these protective layers is subject to strict regulatory scrutiny, as they must maintain their integrity under various storage conditions. If the barrier is brittle, it may crack during the creasing and folding of the carton, which creates channels for chemical migration. Designers must therefore balance the stiffness of the coating with its flexibility to ensure that the barrier remains intact at the corners of the box.
Migration testing on the final folded package confirms that the barrier performs under real-world conditions. This validation is necessary to comply with international food contact regulations.
