Part 1: Overview for Food and Consumer Goods
Introduction
Paper-based packaging is often considered an environmentally friendly alternative to pure plastic. In recent years, a trend towards more fibre-based packaging for food and everyday items has been observed in the EU. But appearances can be deceptive: many of these paper and cardboard packaging materials contain plastic components, for example in the form of thin coatings or films, to fulfill certain functions. In fact, plastics are used in most food-related paper packaging, which means that nominally “plastic-free” or “compostable” packaging often does contain plastic. This introductory article highlights typical reasons for such plastic layers, common plastic types and their functions, initial regulatory aspects in the EU context, as well as environmental aspects (recycling, microplastics, compostability). It forms the beginning of a series of blog posts and is intended to provide a fundamental overview.
Reasons for Plastic Components in Paper Packaging
Paper alone does not provide all the properties required for the protection and shelf life of packaged goods. Without a chemical or plastic-based coating, paper/cardboard cannot fulfill many packaging functions – especially in direct food contact. For this reason, paper is often provided with a thin plastic layer that serves as a functional barrier. Typical reasons for using plastic components are:
- Moisture and liquid protection: Paper is naturally permeable to water and water vapor. A plastic coating, however, makes the packaging resistant to water, moisture and liquids, so that, for example, no water or water vapor can penetrate. This prevents the paper from softening or becoming soaked – for example with frozen food packaging or cups for hot beverages.
- Grease and oil barrier: Foods with high fat content (fast food, baked goods, snacks) require a grease-resistant inner coating. Plastic layers prevent grease from penetrating the packaging. Without this barrier, oils and fats would penetrate the paper and make it soggy or unsightly.
- Gas and aroma protection: Many foods must be protected from oxygen, carbon dioxide or other gases to ensure a long shelf life. Paper is gas-permeable; therefore, a plastic with very low permeability is often incorporated. For example, special polymers provide an almost tight oxygen and aroma barrier, so that the aroma of coffee is preserved in paper-based coffee packaging and no air penetrates from outside.
- Hygiene and product safety: A continuous plastic layer on the inside can serve as a safe contact surface for food. It prevents fibers or particles from the paper from getting into the food and can thus ensure sensory neutrality (no foreign odor or taste). In addition, such layers can act as a functional barrier that reduces the migration of undesirable substances (e.g. printing inks from the paper) into the food.
- Sealability: Many packaging materials – pouches, coated paper films, to-go cup lids, etc. – must be heat-sealed to close tightly. Pure paper cannot be easily welded. The plastic component, however, is heat-sealable, meaning it melts when heated and thus enables stable seal seams. Without a plastic component, for example, coffee cups could not be tightly sealed with lids or paper pouches could not be automatically sealed.
- Mechanical stability: In some cases, the plastic component also contributes to the tear resistance and stabilization of the composite material. The plastic layer can reinforce the paper and make it less susceptible to tears, punctures or mechanical stress – important, for example, with heavy or sharp packaged goods.
In summary, thin plastic layers make it possible to give paper-based packaging similar protective properties to pure plastic packaging without losing the external appearance as “cardboard/paper”. Moisture, grease, gases and germs are kept out and the packaging remains stable and sealable, which is crucial for securing product quality and shelf life. Studies typically quantify the plastic content of such functionalized paper packaging at up to about 10-20 percent by weight of the total packaging – a seemingly small proportion that, however, has a large impact on the packaging’s performance.
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Author: Dr. Daniel Wachtendorf, Innoform GmbH August 2025
