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Films | Flexibles | Bags

Films | Flexibles | Bags Green films in all colours Fig. 1: Variety of Huhtamaki‘s coloured PLA films Huhtamaki Films is an internationally recognised manufacturer of special films of the highest quality - individually developed according to customer requirements. Within the last two decades the company completed its range of innovative products by developing films from materials with a sustainable background, which means that they are biodegradable, compostable or derived from renewable resources. Having been a pioneer in bio-films Huhtamaki is one of today‘s most experienced producers in this sector with an outstandingly broad know-how covering production and converting processes, that was gathered throughout the years, in part in cooperation with a multiplicity of customers. Recently, besides biodegradability, the origin of the materials used for creating sustainable packaging hasbeen gaining in importance. Therefore, the focus is more and more on renewable materials as a source for deriving biopolymers. With Huhtamaki, the development of new films based on these renewable materials such as, polylactic acid (PLA), thermoplastic starch (TPS), green polyethylene (PE) and polyethylene furanoate (PEF) is an ongoing process. A broad range of inventive films also offers the possibility to integrate new functionalities by combining bio-based materials with conventional ones. These films, which may additionally be biodegradable, consist mainly of polymers derived from renewable raw materials and are able to meet the multiple requirements of the very diverse customers within the bio-packaging market. Bio-films Huhtamaki‘s bio-films, with a thickness in the range of 20 to 100 µm, are all produced using blown film extrusion lines with up to 5 different layers. PLA Films Films made from PLA are highly transparent and glossy, enabling an uninterrupted view of the goods packed inside. Using special masterbatches, it is possible to homogeneously tint them in a variety of different colours with the option of preserving their original transparency (cf. fig. 1). As pure PLA is very rigid, Huhtamaki‘s PLA films are all flexibilised with a biodegradable modifier to enhance their mechanical properties. Because of the flexibilisation, especially the reduction of Young‘s modulus, these films are less noisy during processing and application. All PLA films are approved for food contact. They do not contain migrating substances, are grease resistant and exhibit a good barrier for aroma and alcohol. As PLA films possess an excellent deadfold and twisting behaviour, they are suitable for all kinds of wrapping applications such as candies, cheese or bread. Due to the relatively high transmission rates for oxygen and water vapour normally no additional anti-fog coating of the film is required when packing fresh food. If there is a need for a perforated packaging, the films can easily be die-cut. All PLA films can be sealed at temperatures lower than film made from conventional polyolefins, thus, saving energy while 18 bioplastics MAGAZINE [06/12] Vol. 7

Films | Flexibles | Bags by Larissa Zirkel R&D Manager Technical Markets & Speciality Packaging Huhtamaki Films Germany Forchheim / Germany Fig. 3: Fully biodegradable, embossed, metallised and hot stamped Huhtamaki PLA films on cardboard boxes being processed. If necessary, the films can be equipped with excellent antistatic properties. Customers in general prefer packaging that offers them the utmost convenience while handling. One option to generate such a packaging is to incorporate an easy-to-open function. Due to the coextrusion process for producing Huhtamaki‘s PLA films, one of the outer layers can be equipped with a peel function. By varying the amount of peeling agent, the resulting sealing strength of the films can be adjusted to exactly meet the customer’s specific requirements. Therefore, the perfect opening force can be achieved by adapting the peel layer composition to the geometry of the seal and sealing device. The continuous reduction of sealing strength with increasing amount of peeling agent is shown in figure 2. Another added value is the individualization of the packaging. Besides colour, a print design can help attract the customer‘s attention. Due to their high surface tension, PLA films can easily be printed. For decoration purposes, Huhtamaki also offers various embossing designs, metallised and silk matt films (cf. fig. 3). All these films are based on more than 80% renewable resources.They are fully industrially compostable in accordance with DIN EN 13432 and therefore physiologically harmless. Due to the co-extrusion process, the combination of PLA with conventional polymers offers the possibility of integrating new functions such as barrier properties. In contrast to a barrier coating, the benefit of the co-extruded structure is the protection of the barrier layer in the middle of the film by the PLA outer layers. Protection against scratching, peel-off or splintering, which would cause a leakage in the barrier layer, is a key feature. Moreover, due to the co-extrusion technique the films remain sealable on both sides. With this technology, transparent barrier films can be produced with transmission rates of < 3 cm³/m²*d for oxygen and < 25 g/m²*d for water vapour. However, these films are no longer biodegradable but are mainly based on renewable resources, and can be certified according to the star system of Vinçotte (based on renewable carbon content 14 C/ 12 C as per ASTM D6866) with up to three stars for a content of 60-80% of bio-based materials. Sealing Strength in N/15mm 30 25 20 15 10 5 0 Amount of Peeling Agent Fig. 2: Variation of sealing strength of Huhtamaki PLA films with increasing amount of peeling agent bioplastics MAGAZINE [06/12] Vol. 7 19

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