Extrusion Coating

Extrusionsbeschichtung von Papier mit PHBV – eine Alternative zu Polyolefinen?

Sven Sängerlaub, Marleen Brüggemann, Norbert Rodler, Dieter Bauer, Fraunhofer IVV Freising

The biopolymer poly-(hydroxybutyrate-co-hydroxyvalerate) (PHBV) remains in the focus of research because it can be obtained from residues and by-products of food production. A major advantage of PHBV is its very good biodegradability, also in soil and marine environments. PHBV is formed by bacteria and it is extracted from them. In order to be widely used in the industry, its technical and economic usefulness must be demonstrated for various applications. The subject of this study was the use of PHBV for the extrusion coating of paper. These papers are to be used as service papers, e.g. as wrapping papers, for bakery products and for «to go snacks». These «to go packagings» are repeatedly released into the environment by consumers through their naivety and their carelessness. Since these packagings are often coated with plastic, e.g. polyolefins, these plastics and the resulting microplastics accumulate in the environment. A fully biodegradable packaging with a PHBV layer would avoid this undesirable effect. PHBV is a copolymer of hydroxybutyrates and hydroxyvalerates. The mechanical and thermal properties depend on the valerate content (3HV). With increasing 3HV content, the crystallinity decreases in comparison to the homopolymer PHB. The melt temperatures reduce also. This indicates a change in the crystal structure. As the crystallinity decreases, the material properties change.

Fraunhofer-Institut für Verfahrenstechnik und Verpackung, IVV D-85354 Freising, Germany, www.ivv.fraunhofer.de