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POLYFEA – a strong partner in compostable plastics

The company POLYFEA Polymer- und Produktentwicklung, based in the southern Black Forest (Germany), offers consulting for and contract development of polymer-based materials and products. Using the biodegradable material system CAPROWAX P, the company has successfully developed an innovative product.

Albrecht Dinkelaker has become a specialist in the development of polymers thanks to his long experience in polymer syntheses and application development in the chemical industry. Dinkelaker founded POLYFEA Polymer- und Produktentwicklung in 1994, making use of his profound knowledge in the chemical and compost recycling of plastics: the new material he had in mind to develop was waterproof and consisted mainly of renewable materials. Compostable plastics made of starch rarely have sufficient stability for everyday use because they tend to absorb moisture heavily. The material system CAPROWAX P developed by POLYFEA addresses this problem and has the properties required to make plastic materials fit for everyday use: it is waterproof, compostable and stable to use. Nowadays, CAPROWAX P is used in agriculture, horticulture, tree nurseries and viticulture as well as in floristry and forestry. In addition, the material is a compostable material as certified by DIN EN 13432 (registered with CERTCO 7W0069).

CAPROWAX P is easy to process

Albrecht Dinkelaker presenting the CAPROWAX P product range at the NAROTECH tradeshow in Erfurt. © POLYFEA

POLYFEA specialises in consultation and formula development in the field of technical polymers and additives for polymer mixtures using extrusion and coating machines. A major focus of the company is the commercialisation of the compostable material CAPROWAX P, a bioplastic that has the fundamental advantage that it can be processed in the same way as normal plastics, despite the fact that it consists of a high proportion of renewable materials. The material, which contains between 30 and 50 per cent modified plant oils, does not need to be pre-dried and can be processed at temperatures of between 80 - 150 °C.

"CAPROWAX P can be used to produce thin-walled containers and thin films, similar to polypropylene," said Dinkelaker, "and is considerably lighter than starch-containing bioplastics."

Besides modified plant triglycerides, the CAPROWAX P compounds consist of a mixture of aliphatic polyesters. "Compared to other compostable polymer blends, the cost/performance ratio of the CAPROWAX P compounds is quite good," explains Albrecht Dinkelaker highlighting the preferential use of renewable materials, which do not contain any food or feed and are free of aromatic compounds and nitrogen compounds. The bioplastic can be used for monofilaments and their textile systems, thermoforming, injection-moulded and blow-moulded products.

The photo shows a stack of CAPROWAX P master batches. The containers contain differently coloured granulates.
CAPROWAX P master batches © POLYFEA
The photo shows blue and yellow injection-moulded cups CAPROWAX P arranged in a pyramide.
Injection-moulded cups made of CAPROWAX P © POLYFEA

Major application in horticulture and agriculture

The CAPROWAX P granulate materials are manufactured by certified contract manufacturers. In addition, there are master batches for the colour of the granulate material, which have already been tested on the technical level. “Some more development work needs to be done, but this can be adapted to the specific requirements of the client,” said Dinkelaker. Using the biodegradable master batches, the product can be easily composted even after dyes have been added. Compost testing with plant pots with a wall thickness of 500 µm showed that an average biological degradation of 94 per cent can be achieved after twelve weeks. “At first, the material degrades very slowly, but subsequently speeds up. Starch-containing plastics react in completely the opposite way,” explained Dinkelaker.

Thermoforming film made of CAPROWAX P © POLYFEA

Dinkelaker envisages that the CAPROWAX P material will be used mainly in horticulture and agriculture. Due to the material's water and mildew resistance, the plastic has stable product properties within one to two plant cultivation periods. Due to its flexibility at low temperatures, the material can be used outdoors all year round and this means that it is suitable for the manufacture of products that are used outdoors over long periods of time - for example plant pots, netting to protect plants from birds as well as geotextiles used to protect soil from erosion.

To test for plant compatibility, plants grown in CAPROWAX P  pots and standard polypropylene (PP) plant pots were compared. The growth behaviour of plants grown in CAPROWAX P pots was no different from that of plants grown in standard PP pots. In addition, the plastic can also be used as hot melt adhesive, as composites with natural short fibres and as a carrier material for biotechnical systems.

Website address: https://www.biooekonomie-bw.de/en/articles/news/polyfea-a-strong-partner-in-compostable-plastics