Paper packaging is increasingly popular, largely because of its natural appearance. Many consumers are opposed to plastics and are therefore eager to shift to paper packaging. However, they don’t know that paper packaging too often contains plastics and synthetic chemistries. Most of them are made to be compatible with the recycling process. Acrylates, for example, are used to “glue” the paper pulp together to form a strong paper, but they readily dissolve when added to water, allowing an easy recycling process.
However, this is not the case for barrier coatings, which are often used to limit the migration of fats and liquids through the paper packaging. Polyethylene coated paper is frequently used in cups and food packaging. This ultra-thin polyethylene coating adds superior properties to the packaging, making it not only impermeable to sauces, gravy, and fats, but also to better conserve the food content. Unfortunately, polyethylene coated paper is very difficult to recycle. Moreover, consumers don’t recognize this type of paper, so it is readily collected, together with the general wastepaper.
As a result, it is hard for recycling plants to separate all polyethylene from the collected wastepaper.
Within the Horizon2020 “Preserve” project, Centexbel is committed to develop the next generation bio-based barrier coatings for paper. These barrier coatings will be made from natural components including waxes, polylactic acid (PLA) and polyhydroxyalkanoates (PHA).
The coatings will be developed to have a good barrier against moist, water and/or fat, while being recyclable and biodegradable.
It is a typical R&D story in which many different emulsions, dispersions and formulations are generated and tested. We often return to the drawing board to consider new inputs of project partners, alternative curing solutions and more. Each generated sample is tested for its barrier properties. One of the most important ones is the COBB test that measures water absorption of the paper board (see right hand picture).
It goes without saying that a R&D project is the work of a larger cooperation between the project partners. The Preserve project is coordinated by IRIS in Spain. Centexbel and Aimplas develop the paper coatings in close collaboration with paper producer Graphic Packaging International (GPI) and some major end-users like Danone and Ferrero.
Because it is important to generate a broad integrated research, where many aspects including the end-of-life or biodegradability are investigated, many other partners are also involved.
Preserve has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 952983.
Credits:
Created with images by JernejaR - "banana bread bread baking" • Evilowl - "yellow cups paper cups eco-friendly cups"