Flip-cap lids from bioplastics

Dosing caps for bottles and tubes for food, cosmetics and pharmaceutical applications

Film hinges are flexible and thin-walled hinges made of the same material as the two fixed components it connects. As an integrated feature, they allow easy opening and closing. However, compared to other lids, film hinges allow the production of complete parts in one injection molding process.

They are used in particular for fliptop lids and reusable packaging for food, cosmetics and care products. Plastics for film hinges have to meet high mechanical requirements, as the design of the hinge is normally based on several hundred openings and closings over the entire product life cycle.

Bioplastics for flexible, thin and stable hinges

The selection of the right material depends on various factors. In addition to the mechanical properties, both the type and duration of the load and the surface properties of the required plastic must be analyzed in detail.

Film hinges and fliptop lids require a material that has the necessary softness and ductility to withstand the mechanical stress of repeated opening and closing of the lid. This high so-called flexural fatigue strength is what makes film hinges so durable. Polypropylene (PP) is commonly used for this application. An adequate bio-based 1-to-1 substitute for PP does not yet exist. With our Terralene® compound, we are closing this gap and have developed a bio-based plastic with the desired properties.

Terralene® for high endurance film hinges with high flexural strength

Terralene® is a product family of customized polyethylene compounds based on renewable raw materials. They can be processed on existing production lines without any adjustments. After use, products made from Terralene® can be integrated into existing polyethylene recycling streams; it is 100% recyclable.

Our injection-molded grades for fliptop lids are characterized by a balanced ratio of stiffness and stretchability as well as good flexural fatigue strength. Due to the resistance of Terralene®, this bio-based plastic is ideally suited for film hinges, as in addition to a good barrier, outstanding chemical resistance is also provided. In addition to packaging cosmetics or detergents, Terralene® can also be used for food contact products.