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bioplasticsMAGAZINE_1101

Foam Fig 1: Moulded

Foam Fig 1: Moulded E-PLA body torso. Industrial Trials of E-PLA Foams Fig 2: Moulded E-PLA Underfloor Insulation Block – showing some distortion when moulding parameters are not well optimised Fig 3: Moulded E-PLA Helmet Fig 4: Moulded E-PLA Fish Box Fig 5: Moulded E-PLA Protective Packaging (for an Electrical (Whiteware) Appliance) The Biopolymer Network E-PLA technology uses commercially available polylactic acid (PLA) grades and carbon dioxide as blowing agent to make expanded PLA beads via a proprietary process which has won several awards for innovation. Recently this technology has moved into more widespread production trials using existing polystyrene (EPS) plants. These trials, together with performance tests, have demonstrated that the potential of expanded PLA is more than just an alternative to EPS. While the basic mechanical and thermal insulation properties of E-PLA are similar to those of EPS there are other attributes for E-PLA which allow a potentially wider range of applications other than commodity packaging. For example, E- PLA foam products, as well as being renewably resourced, are likely to be readily composted according to international standards if so desired. Large scale trials Industrial scale trials were performed at several EPS molding manufacturers located in New Zealand and in Europe and USA. The figures show examples of moulded products which have included wig stands, body torsos, helmets, underfloor insulation blocks, appliance protective mouldings, fishboxes, automotive parts and laminated sandwich composite structures. When moulding thicker wall structures control of temperature and pressure is important. When parameters are set up ‘as for EPS moulding’, they can be potentially relatively harsh for an unmodified E-PLA moulding, since the glass transition temperature (T g ) of PLA (about 55ºC) is much lower than for PS (about 95ºC). This can result in difficulty to mould thick articles in particular. The challenge is to make the centre fuse without having the outside shrinking. A torso moulding (shown) was more readily moulded as it was relatively thin (~2 cm). The torsos exhibited very good fusing with a good surface finish. In another trial, for underfloor insulation blocks (thicker parts), as with others, pre-expansion of impregnated Fig 6: Moulded E-PLA car seat part 40 bioplastics MAGAZINE [01/11] Vol. 6

Article contributed by Jean-Philippe Garancher Kate Parker Samir Shah Stephanie Weal Alan Fernyhough All Biopolymer Network/Scion, Rotorua New Zealand commercial PLA beads using commercial equipment, was straightforward. Expansion and moulding parameters were adjusted to attain the desired density and indeed very low bulk densities were easily achieved. As observed in previous trials control of temperature and times throughout was important to achieve good mouldings. If not optimised some distortions can occur (see Figure 2). However, again, this trial produced articles successfully molded using existing commercial EPS equipment. These industrial scale trials are clearly very promising and other trials have produced other parts. See figures 3-6 for other examples of E-PLA mouldings produced at various sites. They show the potential of using the E- PLA technology developed by the Biopolymer Network on existing EPS machinery with minor some adaptations. Many of the initial issues encountered such as nonuniform fusing of thick articles, cooling/de-moulding, can be overcome through either material modifications and/ or optimisation of the various overall integrated process parameters, based on an understanding of the effects of process and material variables on quality and performance. These results indicate that the Biopolymer Network E-PLA technology is a serious alternative to EPS, can be moulded on the same processing equipment without necessitating major modifications, and indeed that ‘E-PLAs‘ will have applications beyond EPS - and beyond packaging. MEET THE BIOPLASTICS INDUSTRY IN HALL 9 COME TO THE EUROPEAN BIOLPLASTICS STAND 9E02 AND SEE OUR PRESENTATIONS ON THE NEWEST DEVELOPMENTS IN BIOPLASTICS PACKAGING! JOIN US FOR A DRINK AND MEET NEW BUSINESS CONTACTS AT DAILY SOCIAL EVENTS SPONSORED BY OUR PARTNERS. Acknowledgements The authors wish to acknowledge: • The Biopolymer Network Ltd., collaboration between AgResearch, Plant and Food Research and Scion, for their support. • NZFRST for funding (BPLY 0801 contract). • Various foam moulders who have contributed to this work AND OUR STRONG PARTNERS IN BIOPLASTICS www.bio-based.eu www.biopolymernetwork.com bioplastics MAGAZINE [01/11] Vol. 6 41

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