Basics References:
Basics References: Degradable plastics This is the most general term. It includes both, plastics that degrade by physical or biological factors (sunlight or heat, or microbial action). So-called oxodegradable (i.e.: degradation accelerated by catalysts or additives at elevated temperatures) or photo-degradable starch-polyethylene plastics can cause environmental problems. This kind of degradation results in small fragments that pollute compost, landfill or marine environment. In addition these materials do not degrade as fast as compostable plastics and may leave small fragments in soil. These degraded hydrophobic fragments with high surface areas can migrate into the water table and soil where they can attract and hold hydrophobic highly toxic elements like PCB and DDT up to one million times background levels – effectively functioning as a toxic chemicals transport system in the environment. Therefore one must ensure that the product is completely biodegradable in a very short time as determined by the disposal infrastructure [2, 3, 4, 5, 6]. Biodegradable Plastics Biodegradable Plastics are plastics that are completely assimilated (utilized) by the microorganisms present in the disposal system as food for their energy (enter into microbial food chain). This complete microbial assimilation/utilization is measured by the complete conversion of the carbon of the test plastic to CO 2 during the microbial process taking place inside the cell. Compostable Plastics In addition to being biodegradable by microorganisms, to call a plastic “compostable”, a time factor has to be obeyed. Regulated for example by the standards ASTM 6400 (Specification for Compostable Plastics), ASTM D6868 (Biodegradable Papercoatings 1 ) or EN 13432 (Compostable Packaging), these materials will biodegrade in an industrial composting environment in less than 180 days. Industrial compost environment means a defined temperature of about 60°C, a defined humidity and microorganisms must be present. Compostable plastics as per this definition do not leave fragments, which persist longer than approx. 12 weeks in the residue, they do not contain heavy metals or toxins and will support plant life. [1] Ramani Narayan, Michigan State University, Biobased & Biodegradable Polymer Materials: Rationale, Drivers, and Technology Exemplars, Presented at the National American Chemical Society, Division of Polymer Chemistry meeting, San Diego (2005); ACS Symposium Ser (An American Chemical Society Publication) 939 June 2006 [2] Joseph Greene, California State University, Biodegradation of Compostable Plastics in Green Yard-Waste Compost Environment, Presented at the International Degradable Plastics Symposium, BioEnvironmental Polymer Society (BEPS), June 17, 2006, Chicago, USA [3] Joeran Reske, Beauty of bioplastics, Waste Management World, 02/03/05, www.earthscan.co.uk [4] From Algalita Marine Research Foundation – www.algalita.org/pelagic_plastic.html [5] Y. Mato, T. Isobe, H. Takada, H. Kahnehiro, C. Ohtake, and T. Kaminuma, Environ. Sci. Technol. 2001, 35, 318-324 [6] Ramani Narayan, Biobased and Biodegradable Polymer Materials: Principles, Concepts, and Technology Exemplars; World Polymer Congress, Acknowledgements: bioplastics MAGAZINE is grateful to Professor Ramani Narayan, Department of Chemical Engineering and Material Science, Michigan State University, Professor Joseph Greene, Department of Mechanical Engineering Mechatronic, Engineering and Manufacturing Technology, California State University, Chico, California, and Joeran Reske, BioPlastics and Compostable Packaging, ISD INTERSEROH Dienstleistungs GmbH, Cologne, Germany for their support. Comments or opinions are welcome, please send them to editor@bioplasticsmagazine.com. 1 Exact title: Specification for Biodegradable Plastics Used as Coatings on Paper and Other Compostable Substrates bioplastics [06/02] Vol. 1 35
Basics A certain number of products made of bioplastics are already available in the market. Almost all of them are labelled with some kind of a logo that tells the consumer about the special character of the plastics material used. These logos and their background are introduced by bioplastics magazine in this series. Here questions such as: What is the origin and history of a logo? What does it mean? Which rules are involved with it? will be adressed. Logos Part 2: The “Compostable” logo of BPI: Latest Developments in North America for Compostable Materials Over the past 24 months, interest in biodegradable and compostable materials has mushroomed, along with products certified by the Biodegradable Products Institute (BPI). Today, the array of BPI approved products includes hot and cold drink cups, trays, plates, and bowls made from palm husks, recycled paper fiber, and cutlery derived from corn. North American manufacturers are looking for ways to maximize the use of renewable materials, in order to lessen the environmental impact of these new products, take advantage of new buying regulations by the US Government and to reduce impacts from higher oil and energy prices. Growth of BPI and Certified Products The BPI started in 2000 with Cereplast, NatureWorks and Novamont as founding members, who were joined shortly thereafter by BASF. The organization was formed to address two issues: • Lack of understanding as to the role of compostable products in today’s society; • Easy identification of products that meet ASTM D6400 (Compostable Plastics) or ASTM D6868 (Compostable Packaging). Norms comparable to EN 13432. The BPI and its members worked with the US Composting Council to create an independent certification effort for compostable products. Moreover, the BPI developed cooperative agreements with DIN Certco and European Bioplastics (formerly IBAW) in Europe and the Biodegradable Plastics Society (BPS) in Japan to harmonize certification procedures and laboratories. This made it possible for manufacturers to save money by testing their materials just once in any of a number of laboratories around the world and then take these results to certification organizations around the world. Additionally as part of the cooperative agreements, the organizations agreed to help create global standards through ISO. The initial applications carrying the BPI’s “Compostable Logo” were primarily bags for the collection of yard trimmings and food scraps. The list continues to expand as manufacturers realize the value of compostable foodservice items. The list of manufacturers continues to grow rapidly, with the approval of two hot drink cup manufacturers in August, 2006. The BPI symbol is licensed to products that demonstrate that they meet ASTM D6400 or ASTM D6868, based on testing in approved, independent labs. Manufacturers of products or resins seeking to certify a product should contact the BPI’s Executive Director to discuss the certification process and costs. This can be done via www.bpiworld.org or by contacting scichair@bpiworld.org. The information needed for the certification process are a product description, formulation information and samples, approved laboratory test results. The compliance to ASTM D6400 or ASTM D6868 including, mineralization data, disintegration data, eco-toxicity data and a heavy metal analysis is also needed. Additionally, if the product has already been certified in Europe or Japan, that information will be helpful. 36 bioplastics [06/02] Vol. 1
