MATERIALS / RECYCLING PETplanet Insider Vol. 23 No. 10/22 www.petpla.net 16 Clay-based additive triples gas barrier properties and boosts strength & UV resistance Improved characteristics US-based startup Berkm reports encouraging test results with no impact on recyclability or transparency and seeks additional funding for scale-up. Berkm Inc, which is based in the Boston, Massachusetts, area of the USA, is an advanced materials startup company that is working on commercialising a new type of clay-based additive for the PET plastic industry. It has secured exclusive licensing for technology developed from 25 years of research at Professor Tsung Yen Tsai’s laboratory at Chung Yuan Christian University, Taiwan. Berkm says that the additive offers a number of potential advantages for PET packaging manufacturers, especially in the food and beverage sectors. It is claimed to enable the practical and commercial production of small (100-200ml) CSD bottles, while reducing the amount of plastic per PET container, leading to savings in raw materials costs. The company further maintains that costs can also be saved in pretreatment for hot-fill applications; reduction or elimination of UV blockers; and that the qualities of recycled PET can also be improved. The particular characteristics of PET that have been shown to be improved during testing are: strength (increased by 66%); distortion caused by heat (37%); gas barrier properties (increased by a factor of 29); and UV resistance (up by a factor of 52). These improvements are claimed to be achieved while maintaining current levels of transparency. The latest round of testing, undertaken by third-party agencies, demonstrated that CSD bottles made with Berkm’s clay-based additive showed a tripling of gas barrier properties, compared with conventional PET, at a loading of 0.3%. Barrier properties can be further increased without compromising transparency, up to 1.2% loading. Berkm claims, in addition, that the improved characteristics are achieved not only without harming recyclability but can actually help bottle-to-bottle recycling when added during in-situ PET polymerisation. It can also be added during mechanical recycling and still improve gas barrier performance and strength, by 37% and 25%, respectively. Industrial scale-up trials were completed in May 2022. The platform technology can be applied to improve the CO2 barrier and O2 barrier properties and does not need different chemistries for different gases. Clay particles in the additive create a tortuous path for gas to travel. In December 2021, Berkm filed a new patent that extended its technology to polyethylene (PE) and polypropylene (PP). Several paid pilot projects are currently being undertaken with a range of brand owners and packaging companies. Berkm is now engaged in fundraising to expand production capacity and engage partners for scale-up. www.berkm.co PET bottles (hazy ones) made via conventional clay technologies and bottles made via Berkm’s technology (transparent one on the right). TEM image of clay layers in PET polymer matrix. The image shows a high degree of exfoliation of clay layers. Clear PET bottles made via Berkm’s clay technology MATERIALS
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