vor 2 Jahren

Issue 01/2017

  • Text
  • Bioplastics
  • Biobased
  • Materials
  • Biodegradable
  • Packaging
  • Plastics
  • Products
  • Foam
  • Renewable
  • Sustainable

Foam Starch based

Foam Starch based particle foam for biodegradable packaging Thanks to a new processing technique, foamable particles that are based on renewable resources can be processed into individual molded parts, e. g. for utilization as packaging material. Subsequent to use, the foam parts are compostable. Due to their product properties – light-weight, insulating, form-fitting – particle foams can be utilized, among other areas, in the automotive, logistics, and packaging sectors. Conventional foams, made of – for example – EPS (expanded polystyrene) or EPP (expanded polypropylene), are based on fossil source materials and are manufactured in molding machines with the help of steam and the effects of temperature and pressure. Jointly with the project partners Loick Biowertstoff and Storopack Deutschland as well as the Institute for Food and Environmental Research (ILU), Fraunhofer UMSICHT has developed an alternative that consists primarily of vegetable starch and water. Additional additives can supplement the formulation. “Our task was to manufacture starch particles that are as sustainable and biodegradable as possible that correspond to conventional, petro-chemically based particles in their properties’ profile,” explained Stephan Kabasci, Head of the Department Biobased Plastics at Fraunhofer UMSICHT. With an eye on the existing packaging market, the pricing also had to be taken into consideration in the selection of the components of the formulation. Temperature-controlled slab press In multiple series of tests with the novel starch particles, different foaming processes were tested. In direct comparison, a temperature-controlled slab press provided for the best results. For this, the starch particles are filled into a forming tool and fixated between two slabs for a specified time under pressure. So-called injection compression molds and/or die tools that feature a punch protruding into the negative mold are being utilized. This allows for a direct build-up of pressure in the direction of the particles located in the mold. For the expansion effect of the material, the pressure is a decisive factor in addition to the correct temperature-control that effects the formation of steam. Then the distance between the two slabs is being increased and the cooling off of the die tool is being initiated. This cooling-down process is carried out under counter-pressure so that the starch particles can expand, however not beyond the desired geometry of the molded part. “This way, we can manufacture compact molded parts with a closed and flat surface,” said Kabasci. Through water pressure and contact pressure, multiple molded parts can be glued to one another and additional geometries can be realized through cutting. Areas of use are, for example, edge protection for the transport of goods that are sensitive to shock, productprotecting spacers in packaging, or the replacement of polystyrene-based floral arrangement foams. Molded foam parts glued together with water. Bisected molded foam part made of starch particles. fill conclude press expand remove (Photos and graph by Fraunhofer UMSICHT 32 bioplastics MAGAZINE [01/17] Vol. 12

Foam The biodegradable foam market in China By: John Leung Consultant, Biosolutions Hongkong (source:Fotolia) Although biodegradable plastics first appeared on the market over 15 years ago, these plastics still only have a share of less than 1 % of the total plastics market. The reality is that the cost of some biodegradable plastics is more than double that of conventional plastics, while their general performance is 20 % lower than comparable plastics. Despite strong governmental support in some countries, the major market for biodegradable plastics is limited to bio-waste collection bags for food waste and garden waste. At the end of life, these bags can be industrially composted or processed via anaerobic digestion, to produce biogas and organic fertilizer. Biodegradable plastics are also used for nursery pots used to transplant seedlings, as clearing non-degradable plastic containers from the soil after harvest is very expensive and the complete removal of these containers is impossible. From the above, it can be concluded that, if biodegradable plastics are to break through, applications should be found which are cost competitive with existing products and can provide better performance. One such application is a biodegradable foam cup to replace existing LDPE-coated paper cups. The market price of a 13 oz. (385 ml) paper cup with LDPE lamination is RMB 0.2 (EUR 0.027) a piece. Made from biodegradable foam, the weight of this same 13 oz. cup can be reduced to 5 g, and the cost to RMB 0.16 (EUR 0,02) a piece - but with the following comparative advantages. Plastic foam is an excellent insulation material; cups containing hot liquids made from plastic foam are therefore far more comfortable for customers to hold. In addition, hot beverages can be kept hot – and ice cream for example can be kept cold - for a much longer time. The PLA-based foam referred to in the above application is biodegradable according to the European standard EN13432 and has a biobased content that is higher than 80 %. In the past, the Chinese government has supported biodegradable mulch film projects in the provinces of Yunnan and Xinguang. The provinces of Hainan and Jinlin have special legislation in place for the application of biodegradable shopping bags. A rubbish classification system has been initiated in every city in China and at least five cities have already launched trial scale anaerobic digestion lines. Those five cities are Beijing, Shanghai, Shenzhen, Guangzhou and Wuhan. Although China today accounts for less than 1 % of the global consumption of biodegradable products, its strong economic growth, huge population and clear government ambition make it the biggest potential market for biodegradable products. China’s Legal and Reforms Committee have watched the biodegradable market for more than 10 years. They are highly interested in the biodegradable foam technology presented and expect to replace PS foam trays in supermarkets and single use serviceware. Guizhou Province will be enacting laws that make the use of biodegradable foam for serviceware compulsory in tourist regions. Since Guizhou Province is one of the poorest areas in China, the China Poverty Relief Fund will fund 100 % of cost of a model factory in Guizhou. lt will provide over 150 permanent job positions. Due to the different political system, legislation processes can be very fast in China. Biodegradable foam products are expected to enter the market in the course of 2017. bioplastics MAGAZINE [01/17] Vol. 12 33

bioplastics MAGAZINE ePaper