Films | Flexibles | Bags
Films | Flexibles | Bags High barrier PLA films by Peter Ettridge Product Development Manager Technical Specialties Amcor Flexibles Europe & Americas Over recent years, Amcor Flexibles has carried out extensive research into SiOx coating of renewable films. PLA (polylactic acid) has proved to be a suitable base film and Amcor Flexibles has developed a thin film coating technology to SiOx coat this special film. The result is an innovative, renewable and compostable (certified) Ceramis ® -PLA barrier film. The thin SiOx coating offers excellent barrier properties against oxygen and water vapour and thus provides the necessary barrier for using PLA films in shelf-stable food packaging. Ceramis-PLA fulfils the requirements of the DIN EN 13432:2000-12 standard and is certified by DIN CERTCO. Unlike other barrier coatings, the SiOx material is an inert inorganic material, and as such it does not affect the compostability or recyclability of the PLA film. As Ceramis- PLA is halogen free, it also avoids any potential environmental hazards associated with halogenated barrier materials. Fig. 1 shows the barrier performance of Ceramis-PLA. When used as part of a laminate structure, Ceramis-PLA gives barrier levels suitable for cheese, cured meat and sensitive dry food. Fig. 1: Barrier performance of Ceramis-PLA OTR [cm 3 / (m 2 24h bar)] at 23°C, 50% RH 10000 1000 100 10 1 0,1 0,1 1 10 100 1000 WVTR [g / (m 2 24h)] at 23°C, 85% RH Retort food Dry bread, cereals, snack food Cheese, cured, meat, dry food Fresh products (MAP), confectionary Fig 2: Coating process Ceramis ® -PLA/PLA (laminate) Ceramis ® -PLA 20 µm PLA 20 µm, plain Manufacturing Process The Ceramis coating mainly consists of silicon dioxide. Silicon dioxide, known in its crystalline form as quartz, is the most common mineral in the earth’s crust. It is also the most common base material for glass manufacturing. When quartz sand is melted it transforms from a crystalline to an amorphous state. In the amorphous state it turns clear and transparent. When cooled down fast enough, the silicon oxide remains in the amorphous state and stays clear, like quartz glass. Ceramis films are manufactured in a high vacuum process. As the coating material, silicon dioxide, is heated by electron beams, it evaporates (Fig 2). It then condenses on the PLA film and forms a very thin glass layer that is conveyed on a cooling roll. The silicon oxide, however, has been modified in such a way that the ‘glass layer’ is flexible and can withstand typical movements of the film. No solvents or other chemicals, which could result in harmful emissions to the environment, are used during the production process; just sand and electricity. 26 bioplastics MAGAZINE [06/12] Vol. 7
Films | Flexibles | Bags Consumers should not take the word ‘glass’ too literally, because the layer is approximately 1,000 times thinner than a human hair and thus cannot be seen by the human eye (Fig 3). Furthermore it can be easily flexed without cracking. Since the layer is so thin, it is necessary to protect it with another plastic film in a laminate structure. Fig 3: Thickness of Ceramis Layer Pinhead 2-3 mm 10 -2 m 10 -3 m 1 millimeter More and more, consumers appreciate the ability to see the product inside the packaging before they buy it, especially in the food market. Ceramis films offer highest clarity, with special grades that provide built-in UV protection. Ceramis-PLA films are finding increasing applications in the market, offering outstanding clarity, excellent product shelf life, in combination with renewability and usability for compostable packaging. Dust mite 200 micron 10 -4 m 10 -5 m 10 -6 m 1 µm (micron) www.amcor.com/ceramis Human hair 60 micron 10 -7 m Ceramis ® layer thickness range 10 -8 m 10 -9 m 1 nanometer 10 -10 m New ‘basics‘ book on bioplastics This new book, created and published by Polymedia Publisher, maker of bioplastics MAGAZINE is now available in English and German language. The book is intended to offer a rapid and uncomplicated introduction into the subject of bioplastics, and is aimed at all interested readers, in particular those who have not yet had the opportunity to dig deeply into the subject, such as students, those just joining this industry, and lay readers. It gives an introduction to plastics and bioplastics, explains which renewable resources can be used to produce bioplastics, what types of bioplastic exist, and which ones are already on the market. Further aspects, such as market development, the agricultural land required, and waste disposal, are also examined. An extensive index allows the reader to find specific aspects quickly, and is complemented by a comprehensive literature list and a guide to sources of additional information on the Internet. The author Michael Thielen is editor and publisher bioplastics MAGAZINE. He is a qualified machinery design engineer with a degree in plastics technology from the RWTH University in Aachen. He has written several books on the subject of blowmoulding technology and disseminated his knowledge of plastics in numerous presentations, seminars, guest lectures and teaching assignments. 110 pages full color, paperback ISBN 978-3-9814981-1-0: Bioplastics ISBN 978-3-9814981-0-3: Biokunststoffe Order now for € 18.65 or US-$ 25.00 (+ VAT where applicable, plus shipping and handling, ask for details) order at www.bioplasticsmagazine.de/books, by phone +49 2161 6884463 or by e-mail books@bioplasticsmagazine.com bioplastics MAGAZINE [06/12] Vol. 7 27
