CAPS & CLOSURES 18 PETplanet Insider Vol. 25 No. 01+02/24 www.petpla.net Boosting sustainability by lightweighting closures while maintaining performance and structural integrity Weight savings combined with high performance Beverage brand owners and/or packaging manufacturers are working to reduce the impacts their businesses have on the environment. The motivations for these efforts can legislative, or to better align with the values of their stakeholders (e.g. ESG compliance). Husky’s beverage closure business is helping to enable the circular economy with its manufacturing technology. While significant focus on lightweighting is placed on the PET bottle, the closure can also make a meaningful contribution to further improve the sustainability of the overall package. Husky has developed a leading portfolio of closures in terms of weight and performance. Weight optimisation is achieved using sophisticated simulation tools backed up with a deep knowledge base. The basic concept of lightweighting is simple. Remove as much resin from specific closure features as possible without impacting performance or the user experience. A lower part weight requires less time to manufacture thereby improving productivity. Reducing the amount of resin used in each closure may involve the modification of feature specific geometry. These geometric modifications are subject to multiple simulations, to ensure performance is at least maintained or improved. An iterative simulation approach is applied until the performance criteria are satisfied. Fig 1: A 29/25 still water closure broken out into its fundamental elements. Simulation tools are used to predict how much material can be removed from each feature without negatively impacting performance/usability. Husky says that it has developed a leading portfolio of ultra-lightweight closures leveraging extensive use of mechanical and melt flow simulation tools. The process involves breaking the closure down into its specific features (Fig. 1), and focusing on material removal without compromising performance or usability. Simulation tools are used to predict performance behaviour. The features are modified accordingly until the target weight is achieved and simulation outcomes are favourable. Fig. 2: Popular neck finish options (CSD) The introduction of new industry standard neck finishes presents an opportunity to develop higher levels of performance at a lighter weight. Fig. 2 identifies the most common neck finishes used for CSD applications. While other CSD neck finishes exist, these tend to have a regional focus and are not as widespread on a global level (e.g. PCO1873). The recently introduced 26/22 CSD family (GME30.37, GME30.40, & GME30.41) of neck finishes offers opportunities for weight savings combined with a high level of performance. PCO1881 (3.81 g) is the most common CSD finish globally. The next generation 26/22 CSD neck finishes range in weight from 2.30-2.70 g. Fig. 3 identifies the critical dimensions of PCO1881 compared with the new 26/22 CSD options. All three 26/22 CSD finishes feature the same inner bore diameter of 21.7418mm (same as PCO1881), thereby preserving the drinking experience. The GME 30.40 and GME 30.41 finishes offer a higher performance rating for gas carbonation at 5.2 vol, compared with 4.5 vol for the PCO1881 finish. GME 30.37 offers an even lower rating at 4.2 vol. but with a slight weight savings benefit. GME 30.40 is compatible with tethered caps; GME 30.41 is designed for non-tethered applications. Fig. 4 identifies the most widely used neck finishes for still water. The 25/22 (GME 30.39) and 26/22 3-Start (GME 30.28) have emerged as viable alternatives to the 29/25 (GME 30.26) standard in recent years. The 25/22 and its variants have expanded beyond North America and have seen brand adoption in other regions including Europe, Middle East, SAARC, and Southeast Asia. The key drivers for this adoption are both enviCAPS & CLOSURES Fig. 3: PCO1881 & 26/22 CSD neck finish variants
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