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According to figures from the Federal Environment Agency, Germany alone produces around 6.28 million tons of plastic waste each year. Worldwide, the figure is around 400 million tons. If you then consider that a plastic bottle takes around 500 to 1,000 years to decompose, it quickly becomes clear how critical the situation has now become. Discussions in society and politics have therefore also led to the need to consider new goals in plastics development. The key word here is sustainability. More and more companies are making it a priority to avoid critical products and are increasingly aiming to produce recyclable, biodegradable products.

In the context of this increasing environmental awareness, the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT is conducting research as part of the “Bio2Bottle” project together with four other partners. The researchers are working on bio-based plastics and bottles that meet high standards and are also biodegradable and recyclable. Currently available plastics made from renewable raw materials such as polylactic acid (PLA) are too permeable for storing cleaning agents or agricultural soil additives and do not meet all requirements. PLA is a lactic acid and bio-based polyester with superior mechanical strength – similar to polyethylene terephthalate (PET).

Strict requirements for biodegradable bottles

To meet the requirements – i.e., bio-based and suitable for transport and storage of detergents and agricultural soil additives – the material must have a high water vapor barrier, stability and melt viscosity, the researchers point out. In contrast, the water vapor barrier of PLA is too low for the intended applications, they say. CO2 and oxygen permeability as well as gamma sterilization are also being taken into account in the development of new types of plastics.

In addition to these conditions, the materials must meet another criterion: They must be recyclable and biodegradable, independent of industrial composting facilities. “In this joint project, bio-based polymers are selected and their properties are modified by compounding with additional components to meet these strict requirements,” explains Inna Bretz, Department of Circular and Bio-based Plastics at Fraunhofer UMSICHT. “The goal of the project is to combine bio-based materials and recyclability.”

Extensive experience

“Bio2Bottle” is not the first project for Fraunhofer UMSICHT that deals with the development of marketable plastics based on renewable raw materials. The researchers have been developing circular and bio-based plastics for a variety of applications in films, fibers, filaments, injection molded parts and the like for many years. With “Bio2Bottle,” they now want to show, among other things, that “bottle material can be reprocessed in a technically efficient – and therefore more competitive – recycling process.” In the long term, this should result in a reduction in plastic waste and in the use of petroleum-based raw materials to produce short-lived products. The researchers also want to investigate and further develop the biodegradability of bio-based bottles.

In addition to the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Oberhausen, the project partners are cleaneroo GmbH, Berlin; UnaveraChemLab GmbH (Unavera), Mittenwald; FKuR Kunststoff GmbH (FKuR), Willich; and Fritzmeier Umwelttechnik GmbH & Co. KG (FMU), Großhelfendorf; all of whom are participating in “Bio2Bottle” project.

Cover photo: Plastic pellets for further processing in injection molding or extruders. © Fraunhofer UMSICHT