Folien

Folien, or films, are thin, flexible sheets widely used across packaging, electronics, agriculture and construction. They typically range from a few micrometers to several hundred micrometers in thickness. Materials include polymers such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC) and polylactic acid (PLA); metal foils, notably aluminum; and cellulose-based materials such as cellophane. Many films are multilayer structures that combine different materials to achieve barrier, strength and optical properties.

Production methods: The majority of films are produced by extrusion, in particular cast film extrusion and blown film extrusion. Cast film yields smooth, uniform sheets, while blown film creates highly flexible tubes that are subsequently collapsed. Multilayer laminates are formed by adhesion or co-extrusion, and films can be coated or metallized to modify surface properties and barrier performance.

Properties and applications: Key properties include thickness, transparency, gloss, mechanical strength, elongation, barrier to moisture and oxygen, and heat resistance. Common applications include food and pharmaceutical packaging, protective covers, labeling, electronic insulation, greenhouse and agricultural films, and solar module encapsulation.

Environmental aspects: Recyclability depends on materials and structure. Mono-material films are typically easier to recycle than multilayer composites. Biobased or compostable films (e.g., PLA) are increasingly used in sustainable packaging, though regional recycling infrastructure varies.