Biodegradable high-performance polymer

A new generation of biodegradable polymers consisting of cellulose blends, polylactic acid (PLA) or polyhydroxybutyrate (PHB) are surpassing plastic bags, disposable knives and forks, and packaging for their excellent processability and performance. This is a traditional application area. In addition to their continued use in general packaging and disposables, they can also be used in medical, diagnostic devices and barrier packaging.

Biodegradable polymers that can be processed using conventional methods

FKuR Kunststoffe GmbH (hereinafter referred to as FKuR) and the Fraunhofer Umsicht Research Institute in Oberhausen, Germany, have developed a PLA/polyester blend that can be used in the same process as LDPE blown film. Processing. Experiments conducted by FKuR have shown that this new Bio-Flex 219F material can be processed on a conventional blown film line without any modification of the screw, die head and traction device.

According to the company, Bio-Flex 219F is made of 10% PLA (available from NatureWorks LLC, Minnetonka, Minn., formerly Cargill Dow) and a biodegradable copolyester and compatibilizer. Special additive composition. Due to the effect of the compatibilizer, the PLA and the copolyester undergo a coupling reaction, resulting in a blend with a homogenous structure. Therefore, the processing performance of this material is very good, and the thickness of the blown film can even be controlled to 8 mm. . According to experiments, films made of this material with a thickness of less than 110 mm will degrade by 90% after 12 weeks under natural conditions.

Packaging products made from FKuR's Bio-Flex PLA/polyester blends and injection grade Biograde cellulose blends


Bio-Flex 219F material is mainly used for the production of shopping bags, film and laminates. In addition, FKuR has also developed more rigid Bio-Flex grade materials. Among them, 466F (containing 20% ​​of PLA) and 467F (containing 30% of PLA) are used to process shopping bags, and 482F (including 70% of PLA) is used to process cast films.

Another "natural compound" series material developed by FKuR is modified cellulose. This series has similar processing characteristics and mechanical properties as polystyrene. Among them, Biograde 300A is an injection-grade material that uses natural fillers and special vegetable oils. It can be used in disposable knives and forks and other products. Its color is white. The material has good thermal stability and can be molded on a standard injection molding machine with a universal screw. Due to the low shrinkage of the material, the appearance of the product is not warped. In addition, FKuR also expects to introduce Biograde 500A before the end of this year. This material is mainly used for the injection molding of hot water cups.

Biodegradable polymers that can be processed in a variety of ways

FKuR also recently introduced Biograde 200C, a cellulose-free mixture of fillers and starch that can be recycled 100%. Cast film and injection molded articles made from it have high rigidity and transparency, as well as barrier properties similar to PLA. According to Patrick Zimmermann, marketing manager at FKuR, Biograde 200C has injection molding properties similar to those of polystyrene. It can be used to blow bottles and thermoform cups and trays.

Founded in 1992 as a plastics recycler, FKuR entered the field of biodegradable polymers in 2000 and is now able to produce more than £6 million of biodegradable polymers annually, and its sales network spans the globe. The company's price for this product ranges from 2.85 to 70/kg. According to Zimmermann, FKuR's performance in 2005 will increase by 25% as it continues to enter new market segments such as plastic film materials.

FKuR's Biograde cellulose blends have processing and mechanical properties similar to polystyrene

Unprecedented application prospects in the fields of medicine and food

Biomer, another German company that produces biodegradable polymers, is currently exploring new markets for PHB and PLA polyesters. The company used a microorganism it developed to ferment sugars or starch syrups and then took the extracted PHB or PLA polyesters with low and high molecular weight plasticizers, nucleating agents and other processing aids in three different proportions. Blended into injection grade material. The processing of these three materials is similar to that of liquid crystal polymers. Due to their extremely low melt viscosity (MFR higher than 20 g/10 min), high mold clamping force is not required when injection molding products with complex structures.

Biomer's biodegradable PHB polymer is entering the medical field, such as this injection molded "immune strip" diagnostic tool


According to Biomer, 1.2mm thick samples molded from these materials can be degraded within 6 weeks in the natural environment.

Among these three materials, P226 has mechanical properties similar to PP, and is easy to mold and has a short manufacturing cycle; the mechanical properties of P209 are similar to those of HDPE in general, but because of its crystalline structure, its elongation at break is lower than that of PPE. HDPE is much lower; P240 is toughened on the basis of P209 to make it have higher impact strength. The above three kinds of materials can be injection molded into medical "immune strip" diagnostic tools, pyrotechnic packaging and military exercise barrels and other products. In addition, the company is also able to provide a small number of PLAs designed for injection molding transparent medical diagnostic tapes, as well as PHBs for extruded multifilament surgical fabrics. According to Urmer Hangiggi, president of Biomer, they are developing PHB products with higher melt strength for blow molding of thin films.

Biomer’s product sales are currently growing rapidly, especially in the US market. Its production capacity has reached several tons/month. Hanggi firmly believes that PHB, which is currently priced at 5~10$/pound, will be used as a production material for food packaging such as yogurt cups and beverage bottles in the future, despite its biodegradable characteristics, although it is now licensed for food grade materials. The cost is extremely expensive.