Using Nordic softwood kraft pulp, the team at the VTT Technical Research Center of Finland
thermoformed this sample tray at LUT University with a MiniMould tool using the sliding blank method. This has a draw depth of 35 mm.
Image: Juha Hakulinen, VTT Technical Research Center of Finland

VTT PILOTS CELLULOSE AS ALTERNATIVE TO RIGID POLYPROPYLENE PACKAGING

Finnish researchers have developed highly extensible, formable, cellulose-based webs that they say offer a sustainable alternative to plastic in rigid packaging applications.

Jarmo Kouko, VTT’s research team leader (Photo courtesy of VTT)
Image: Juha Hakulinen, VTT Technical Research Center of Finland

“Polypropylene film is one of the world’s most used polymers. ... Our invention now offers a viable, sustainable alternative on the market,” says Jarmo Kouko, research team leader at the VTT Technical Research Centre of Finland.

The nonprofit VTT did the development work as a part of a research program, via which it cooperated with 54 companies and the Regional Council of Central Finland to create promising, up-scaled alternatives for plastic products. Their pilot-scale efforts yielded unprecedented maximum limits of its highly extensible formable cellulose-based webs.

Typical commercial boards have between 3-6% extensibility (measured via geometrical mean) with the best such boards having 10-18% extensibility. But VTT says that by using foam forming technology, it has now obtained up to 30% extensibility. This enables brand owners to use rigid, cardboard-like packaging to serve consumers looking to buy more sustainable products.

For example, VTT suggests, this could enable food brands making cold cuts to increase cardboard-like package size to 200-250 grams from 75 grams. Users could produce even larger cardboard-like packages by adjusting the tray forming process and tray dimensions.

Kouko said his team is excited about the commercial potential of its rigid, cellulose-based packaging. “In industries that use huge amounts of plastic like the food packaging sector,” he said, “we can find plenty of opportunities to reduce the use of fossil-fuel-based materials and replace them with sustainable ones that take us closer to carbon-neutral societies of the future and allow us to be more frugal with natural resources.”

He sees VTT’s cellulose-based material as a sustainable and affordable alternative to single-use plastic. This is particularly important, he notes, given the ongoing legislative efforts to curb the use of certain polymers.

The top and bottom of another cellulose-based sample tray thermoformed at LUT University with am M6 tool using the sliding blank method.
Image: Juha Hakulinen, VTT Technical Research Center of Finland

Kristian Salminen, VTT’s lead for bio-based products
Image: Juha Hakulinen, VTT Technical Research Center of Finland

He cited the European Commission’s Single-use Plastics Directive and the its proposal for Packaging and Packaging Waste Regulation, under which the European Union banned the use of expanded polystyrene (EPS) food containers and cups in 2021. As a result of these laws, the producers of single-use plastic products are now expected to cover the waste management costs for these products.

Kristian Salminen, VTT’s lead for bio-based products, said that that his team, together with Venice, Italy-based gruppo x di x gruppo srl and Finland’s Lappeenranta-Lahti University of Technology (LUT), was able to incorporate the product into existing product packaging lines with no changes in the process. Doing so makes it “affordable and easy for brands to adopt the product as a sustainable alternative to plastic packages can be a real game-changer.”