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06 | 2010

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Films | Flexibles | Bags

Films | Flexibles | Bags Next Generation PLA Films Article contributed by Dr. Kurt Stark Segment Manager R&D Technical Markets & Specialty Packaging Huhtamaki Forchheim, Germany Figure 1: Comparison of the Young’s modulus of Huhtamaki’s Bio films (coloured) to orientated PLA films and common blown PLA films on the market (left side), and also to common oil based PE and PP films (right side). 1: md direction, 2: td direction, 50 µm Huhtamaki Films, manufacturer and converter of films from Forchheim, Germany, recently presented new developments and the next generation of Bio films based on Polylactic acid (PLA) at the Fachpack in Nuremberg and at the Bioplastics Business Breakfast during K’2010 in Düsseldorf. Huhtamaki Films has already worked on Bio films for almost twenty years. After Bio films based on thermoplastic starch (TPS), Huhtamaki Films began, about six years ago, intensive research on films based on Polylactic acid (PLA). Huhtamaki Films thereby succeeded in producing new proprietary blown and also cast PLA films based on Ingeo by NatureWorks. Tailor-made Bio Films These highly transparent and glossy films exhibit an excellent wide range of properties. The mechanical behaviour, especially the flexibility, can be altered and adjusted to customers‘ requirements. Furthermore, for blown PLA films, the elongation at break is increased to more than 150 % in both directions of the film. The tear resistance has also been enhanced by a factor of 3 to 4 compared with conventional PLA films. A major benefit is the improvement of impact resistance, which is very important for processing these films on common (packaging) machines. Huhtamaki’s biodegradable PLA films have run, up to now, on every common thermoforming or packaging machine. About 25 successful tests have been made on different machines. The brittleness has been overcome by incorporating biodegradable additives. Huhtamaki’s flexible PLA films can be cut very easily, without splintering off. 5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0 1 2 PLA Oriented Film - commercial 4021 5026 PLA Blown Film - commercial 3360 3223 Huhtamaki Quality 75402 2307 2299 Huhtamaki Quality 75404 1873 1813 Huhtamaki Quality 75406 1421 1523 Huhtamaki Quality 75480 1700 1755 Huhtamaki Quality 75496 1653 1705 Huhtamaki Quality 33800 228 175 Huhtamaki Quality 66020 581 375 (Homo) PP-Film 2000 1900 (Random) PP-Film 1101 1102 LDPE-Film 255 303 Figure 1 shows the comparison of the Young’s modulus of Huhtamaki’s Bio films (coloured) to oriented PLA films and common blown PLA films on the market (left side), and also to common oil based PE and PP films (right side). The Young’s modulus in N/mm² (=MPa) is a measure for the stiffness of a film, the higher the value, the stiffer (and more noisy and less flexible) the film. As can be seen from the plot, the Young’s modulus of Huhtamaki’s BioWare PLA films is similar to the values of a PP film, whereas Huhtamaki’s BioWare TPS films (e.g. Quality 33800) have a Young’s modulus being comparable to a PE film. So, having a Young’s modulus starting from about 1400 N/mm 2 and ending at about 3200 N/mm 2 , the new BioWare PLA films can be designed in a wide range from 20 bioplastics MAGAZINE [06/10] Vol. 5

soft to very stiff and therefore modified to customers requirements. This opens the door for further applications and markets where Huhtamaki’s PLA based Bio films can be used to advantage, because the modifcations lead to much better properties for the films. Next generation Bio Films In addition to this, Huhtamaki’s BioWare PLA films can be equipped with further functions. When used as packaging films for food or non-food articles an excellent sealing behaviour and tight sealing for a closed package is required. This is offered by BioWare PLA films, even at lower sealing temperatures between 100-120°C. In many cases, consumers want packages to be easy to open when pulling off a lidding film. To meet this demand, Huhtamaki Films has developed BioWare PLA films that have excellent peel properties. The PLA films are especially suitable for food packaging because of their minimized migration. The blown PLA films have excellent deadfold/twist properties for applications where the film is wrapped around a product that is being packed. BioWare films can also be printed, without any problems, on common printing machines. Huhtamaki Films has machines to print up to 8 colours. The colours used are non-toxic, harmless and according to DIN EN 13432. Pretreatment of the film is recommended, but not always necessary for PLA films because of the high surface tension above 40 mN/m. PLA films are also very suitable for lamination, e.g. film against film or film against paper. Without any modification, Huhtamaki’s PLA films have a high transmission rate to both water vapour and oxygen. With Q. 75446 Huhtamaki Films introduced a PLA film with distinctive antistatic properties. Biodegradable, highly transparent PLA blown films from Huhtamaki Forchheim are available in thicknesses from 20-120 µm in widths up to 1500 mm. Most films are How do we know tHat you will be successful in May 2011? From experience. solutions ahead! düsseldorf, Germany 12 – 18 May 2011 Figure 2: Embossed BioWare PLA film Messe Düsseldorf GmbH Postfach 1010 06 40001 Düsseldorf Germany Tel. +49(0)211/45 60-01 Fax +49(0)211/45 60-6 68 bioplastics MAGAZINE [06/10] Vol. 5 21

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