Displaying items by tag: vtt

VTT Technical Research Centre of Finland is piloting a new transparent cellulose film that reduces microplastic.  

Food packages fulfil their most important tasks when they protect food and minimise waste. Thin plastic films are nevertheless difficult to recycle, and they often end up in the wrong places after use. 

VTT has developed a solution to the problem of plastic packaging. Regenerated or recrystallised cellulose can replace plastic films. 

Technology Manager Heli KangasTechnology Manager Heli Kangas

“We can produce transparent and flexible cellulose film. The consumer cannot distinguish between the crystal-clear material and traditional oil-based plastic. Cellulose film can resist dampness, but in nature it disappears as completely as a sheet of paper does. The product is biobased and biodegradable”, says VTT Research Professor Ali Harlin

In addition to their protective properties, plastics are important because consumers want packages that allow them to see the product itself. However, once they have been used, many packages are sources of problems. If a package has both paper and plastic, the consumer may wonder if it can be recycled with cardboard, or if the plastic needs to be torn off first. Some of the materials have alternating layers of fibre and plastic. Many packages are placed among mixed waste by people who cannot think of a better way of disposing of it. Plastic that ends up in a cardboard recycling bin can be removed, but the plastic usually ends up incinerated. 

“The cellulose film developed by VTT can replace plastic as a more climate-friendly solution. It also makes recycling easy, as it can be placed in cardboard recycling along with other packages”, says Atte Virtanen, Vice President, for Biomaterial processing and products at VTT. 

Cellulose film pilot line in VTT BioruukkiCellulose film pilot line in VTT Bioruukki

Finland remains far from the goals set by the EU for reducing the environmental harm caused by plastics. At present, about 20 percent of plastics are collected, and even less end up recycled. Under the EU target, 55 percent of plastics should be recycled by 2025. 

Plastic film market is worth 110 billion dollars 

Finland is currently more of a packaging material country than a printing paper country. Last year the value of sales of cardboard exceeded that of paper for the first time. The forest industry is looking for new products with a big market, which brings value-added. Flexible, transparent cellulose film is one such product. The world market for plastic films was about 110 billion dollars last year. 

VTT's unique expertise has been used in cellulose film as a replacement for plastic. 
“VTT has researched cellulose films for more than ten years, and for more than six years on regenerated cellulose in transparent films”, Virtanen says. 

The production of packaging material is in the pilot phase, and it could be in extensive industrial use in 5–7 years. 

VTT is a visionary research, development and innovation partner. We drive sustainable growth and tackle the biggest global challenges of our time, and turn them into growth opportunities. We go beyond the obvious to help society and companies to grow through technological innovations. We have 80 years of experience in top-level research and science-based results. VTT is at the sweet spot where innovation and business come together.

VTT – beyond the obvious

Published in Bio packaging
Tagged under

VTT is testing Thermocell plastic film made of cellulose and fatty acids in the production of food packaging in cooperation with Arla Foods, Paulig, and Wipak. Thermocell plastic material, which is made from renewable components, is to be used in the same way as fossil-based plastic. Thanks to the development work, many features of the film already meet the requirements of the food industry, and cooperation has advanced to the testing of industrial production.

Renewable origin and recyclability of packaging materials are of increasing interest to both consumers and packers. Bio-based options are being sought for oil-based, or fossil-based plastics, which could be worked, used, and recycled like traditional plastics. One emerging solution is cellulose, the structural ingredient in plants which, just like plastics, is composed of large polymer molecules. When cellulose is extracted from wood, it does not compete with food production, as many other biomaterials do. In addition, efficient production methods have already been established in the production of cellulose. However, cellulose as such has lacked one important feature of packaging plastic: thermoplasticity.

VTT developed the thermoplastic features for the needs of the food industry

2021 02 17 090404A method developed by VTT enables the production of Thermocell plastic, a thermoplastic substance, out of cellulose and bio-based fatty acids, which are suitable for applications such as injection molding, coating of paper and paperboard, and 3D printing. The current focus of development work in the manufacture of films is in extrusion technology.

“We have moved from the laboratory to bigger machinery while at the same time improving the quality of the film. Our goal is to show that Thermocell film can be produced on an industrial scale using the same equipment that is used for traditional plastic films, with features that meet the needs of the food industry. For this reason, Arla Foods, Paulig, and Wipak are also taking part in the research”, says Jarmo Ropponen, the research team leader at VTT.

“The focus in our development of packaging in the coming years is on recyclability. The development of renewable, bio-based materials supports our long-term goals. The development of Thermocell still requires work to ensure that it can be used with machinery, and that it has long shelf life, among other features. We wanted to support material development so that the requirements of our products will be considered already in the early stages of development”, says Kati Randell of Paulig.

A thin, durable, protective, and safe film is required

Food packaging favours films that are as thin and durable as possible, but yet protect foods safely. Thermocell has already been shown to provide good protection against water vapour, and none of its components migrate into the food. Thermocell film can also be heat sealed using the manufacturers’ standard equipment.

A significant achievement in the development of Thermocell is the smaller thickness of the film. With advances in production machinery, the film has become more even, and its thickness is already down to 100 micrometres. If the material is to compete against thin plastic films, the thickness needs to be reduced further. The aim is also to orient the film and thereby improve its strength and its protective qualities.

Feedback from partner companies has also allowed us to see other features that are important on the market. The friction characteristics of the film are one example of this, so that it could be more easily used on industrial packaging lines”, Ropponen says. 

The recyclability of Thermocell has proven to be nearly equal to that of the most common thermoplastics. It can be melted down and extruded again at least five times with no significant deterioration of its features. Recycling still requires that it should be sorted separately. 

Thermoplastic bio-based plastic without additives

The first cellulose-based plastics were developed already before anyone even thought of using oil as a raw material. Cellulose acetates, which are still extensively used, date back to that time but their thermoplastic properties require large amounts of additives. Thermocell, which is produced from cellulose and fatty acids, shows thermoplastic behaviour with no additional substances at all.

In the method developed by VTT, cellulose polymers are split into shorter chains before adding fatty acids, improving the reactivity of the cellulose, making the resulting material more thermoplastic. At the same time, it gives better protection against water and it can be more easily heat sealed.

“In our most recent test runs we have utilised small amounts of traditional plastic additives because they make it easier to manufacture film, and improve its features”, Ropponen says. 

Once the research group has completed the fine-tuning of the traditional plastic film applications to suit the needs of packers, the focus of development work can be shifted to practical recycling concepts. The aim is to adapt the film to collection and recycling systems that are used on the main markets in the world.

Published in Bio packaging
Tagged under

By clicking “Accept All Cookies”, you agree to the storing of cookies on your device to enhance site navigation, analyze site usage. Site Terms and conditions