Processing Frank
Processing Frank Haesendonckx, Product Manager at SIG Corpoplast answers a few questions about high speed stretch blowmoulding of PLA-bottles. bioplastics MAGAZINE (bM): Can PLA be blowmoulded on standard equipment? Frank Haesendonckx: Even though the processing of PLA preforms and bottles can be implemented on “standard“ machines, several aspects have to be taken into account to produce bottles which meet the economical and industrial requirements. bM: For example? Interview: PLA blow moulding The first PLA-bottle in the USA, introduced by Biota from Ouray, Colorado and the first one in Europe from Belu, London, UK are stretch blowmoulded on BLOMAX machines from SIG Corpoplast, Hamburg, Germany. www.sigcorpoplast.com Frank Haesendonckx: For example the preform geometry: The behaviour of PLA is different from PET when stretching on a stretch blow moulding machine. It is therefore essential to adjust the preform geometry accordingly. We offer our Bottles&Shapes TM - expertise to help customers design the optimal preform. bM: What else has to be considered? Frank Haesendonckx: For optimal preheating in the infrared oven, the absorption behaviour of PLA requires additional “Carbon- Black“ additives which are also used in PET. The industry already provides biodegradable additives for this purpose. The transparency of the bottle is not or only inconspicuously influenced. Low heating temperatures are sufficient for PLA preheating. The heating profile in the oven must be adjusted to the preform geometry and the material properties. bM: And what about the actual blowing process? Frank Haesendonckx: The preblow-pressure for PLA stretch blowing corresponds to the pressure required for PET. The starting point for pre-blowing as well as the stretching rate must be adjusted for PLA. bM: We often hear about limited mechanical and thermal properties of PLA bottles? Frank Haesendonckx: The mechanical properties of PLA, which still do not meet those of PET, can be compensated for via skilful bottle design. For example, the stackability can be improved by an optimized bottle geometry. The thermal properties of PLA can still not be compared to PET. The bottle shrinkage which already starts at 45°C can partially be improved by deploying a so-called “relax“ process. bM: How do you see the future of PLA as a bottle material? Frank Haesendonckx: PLA will be an increasingly interesting material for stretch blow moulding due to the rising oil price in the medium and long term. However, further improvements with regard to raw material as well as thermal and mechanical properties are essential. The main areas of application are still waters, products with short shelf life and products which are not hot filled. Further applications are provided if the barrier properties can be enhanced. A complete separation between material and product is guaranteed via use of SIG’s PLASMAX inner coating technology which enables packaging of sensitive beverages or food in PLA and ensures product quality. bM: Thank you very much 22 bioplastics MAGAZINE [02/07] Vol. 2
Week 1 Week 2 Week 3 Week 4 BIODEGRADATION PROCESS EcoWorks ® www.EcoFilm.com info@CortecVCI.com 1-800-4-CORTEC St. Paul, MN 55110 USA © Cortec Corporation 2006 70® 100% Biodegradable EcoWorks Replacement for Plastic and Polyethylene Up to 70% Bio-based With Annually Renewable Resources From thick rigid plastic cards to fl exible protective wrap, EcoWorks ® 70 by Cortec ® Research Chemists offers universal, biodegradable replacement to traditional plastic and polyethylene films. This patent pending breakthrough meets ASTM D6400 and DIN V 54 900. EcoWorks ® 70 does not contain polyethylene or starch but relies heavily on renewable, bio-based polyester from corn. 100% biodegradable, it turns into water and carbon dioxide in commercial composting. ioPlastic.indd 1 8/2/06 8:44:40 AM
