Partnerships are long and cooperation is close.

The companies chosen to provide Bioska’s raw materials engage in sustainable production. Our partnerships are long and cooperation is close, starting right at the very beginning with material development. Close cooperation ensures that our products are as well suited to their purpose as possible.

The raw materials for our products arrive at our Ylöjärvi plant as granulates. These granulates are then blended to form a variety of raw material mixtures. The mixtures used for home composting are softer, stretchier and more degradable than those intended for industrial composting. For example, you can see how a lot of the stretch has been eliminated from a shopping bag in comparison to a biowaste bag.

Both single-layer and multilayer products available

The mixtures are melted, and the films are formed using blown film extrusion. We make both single- and multilayer films.

For example, Bioska and BioskaPlus use single-layer films. Multilayer films are used in shopping bags and in most of the compostable Walki®Bioska protective and packaging films.

Multilayer films can be made symmetrically, so they will stay straight when placed on a table – just like a piece of paper. Asymmetric films will be rolled, as the surface tensions of the innermost and outermost layers are different. Making the innermost and outermost layers from different materials results in easy-to-use packaging materials. The innermost material clings together even at low temperatures, but the outermost layer doesn’t, so a closed package won’t stick to the production line.

By adding different raw materials to different layers, even fine films can achieve good tensile strength and bursting strength.

Biowaste sorting stations need new materials

R&D cooperation with our partners is ongoing in a number of areas. For example, Bioska specialists are currently working with the City of Oslo to find out how a biogas plant that uses an optical reader in its biowaste sorting process can switch from traditional plastic bags to compostable bags.

Regular biowaste bags can’t withstand the vibrations and pressure blasting of this process. However, plastic residue from traditional bags is not acceptable to farmers, who use the products they receive from the biogas plant as nutrients for their fields. The solution now being tested is triple-layer, black-and-white Walki®Bioska 903 packaging film.