Special Compostable
Special Compostable Films and Trays The revolution in the food packaging sector. Article contributed by Stefano Facco, New Business Development Manager Novamont S.p.A., Novara, Italy The development of compostable polymers in the trays and films sector has enjoyed a dramatic boost in recent years. We may describe it mainly based on two aspects. The first aspect is the technical improvement in terms of performance and processing: lately we have seen more and more “high tech” biopolymers with properties similar to or, in some very specific cases, even better than standard polymers. The second aspect is the change in attitude of retailers and consumers, and the approach to waste management issues. Compostable and biobased polymers have, in the last 4 to 5 years, demonstrated a really outstanding development, which has enabled them to be used almost as standard polymers in specific packaging applications. Major producers are based in Europe (such as Wentus, Amcor, Innovia, Treophan etc), as well as in the USA. In the food sector in particular new packaging for different products has been shown to have reached performances as high as some standard products. Starting from thermoformed punnets and trays, the market today offers products which may be as tough as the equivalent conventional ones. Also, in terms of processing, standard extrusion lines such as used for PP may be used for bioploymers. Another important aspect is given by the capability of recycling these new materials. This is a very important aspect when considering extrusion and thermoforming, as some 30% of scrap may result from a standard thermoforming process. And not only toughness, but also puncture resistance and rigidity have reached very high levels. In terms of transparency, a variety of companies do offer either very transparent or white opalescent products. Linear shrinkage values are comparable to standard polymers and may vary as from PP to PS. The Tg values, which may be a reason to choose 18 bioplastics MAGAZINE [03/07] Vol. 2
Special a particular polymer (depending whether a punnet is used under deep frozen or ambient conditions), range from below 0°C to above 40°C. If the development of rigid trays has already reached a very high industrial level, the expanded tray sector is very close to reaching similar standards. Some different products are starting to show up in first applications and there are a number of products which have been shown to perform quite well. The first one, very close to being introduced in the UK (produced by Sirap Gema), which is a new and very light product, has been demonstrated to be, in the case of packaging delicate produce, even better compared to a standard EPS in terms of its cushioning properties. It has a very soft touch, white colour and has been tested by a major packaging company which has carried out a comparable test amongst major producers of trays (rigid and expanded). The results were really astonishing, as this new material shows incredible performance profiles in terms of handling and cushioning. In addition some products are starting to slowly move into the market, although we still may not consider them as expanded, as they belong more to the sheets category, but which are lighter compared to a standard sheet / tray, showing an expanded core and a still-rigid skin. Most of these products described above do have, due to their morphology, a white or opaque colour. A very new technology is soon to be launched on the market, namely laminated paper / cardboard trays. In this case we do have different technologies available, either based on coatings from a solution, or laminated with a compostable film. A third technology is based on extrusion coating (Mondi Packaging). Specifically in this latter technology, the possibility to use such extrusion coated trays may open up applications such as for microwavable food, as it seems that the weakening and melting points do satisfy the needs of such “cooking technology”. For standard coated paper/board (for frozen and room temperature applications) different polymers are already available on the market. But, as a filled punnet should not loose its content, there is a need for specific films or nets, in order to complete the packaging unit. Compostable and biobased films started their development many years ago and the results are very well visible on the market, if we consider the very high percentage of biopolymers used. According to different studies some two thirds of the given applications in the biopolymers sector is covered by films. Newly introduced wicketed bags, films for VFFS and flow pack have demonstrated the very high level achieved. The 9th Annual Bioplastics Conference Performance through innovation Featuring presentations from ■ NEC ■ Metabolix ■ FKuR ■ NNZ ■ Utrecht University ■ Braskem ■ PA Consulting ■ Natureworks ■ Tianan Biologic ■ PSM ■ Eosta / The Organic Salad Company Plus – includes the second annual Bioplastics Awards 5 – 6 December 2007 - Hyatt Regency, Cologne, Germany To register - Tel: +44 (0)20 7554 5811 (International) 0845 056 5069 (UK Only) Email: EPNconferences@emap.com Online: www.bpevent.com Organised by: 2007 Conference & Awards
