PETpla.net Insider 06 / 2017

PREFORM PRODUCTION PET planet Insider Vol. 18 No. 06/17 www.petpla.net 14 On the one hand a PET bottle must stay stable so that customers can continue to use it comfortably and it remains unbreakable. On the other a carbonated medium in the bottle requires a certain wall thickness in order that only the stipulated amount of CO 2 is diffused and the bottle can withstand the internal pressure. The preform must also safely survive the production process both in the stretch blow moulder and then as a bottle on the filling system. There are thus many reasons why the material and consequently the weight of the PET bottle cannot be reduced any further. With more efficient bottle shapes and ever thinner wall thicknesses KHS has nevertheless been able to make considerable savings in weight in the past. “We’re increasingly noticing that current containers are now reaching their limits when it comes to wall thick- ness. We’re thus turning our attention to other parts of the bottle,” says Arne Wiese, product manager for Bottles & Shapes at KHS. He and his team still see potential in the bottle thread area in particular, yet here, too, there is a lot to be taken into consideration. The best-known and most widely used thread is what is known as the PCO 1881. This is a voluntary stand- ard with a thread diameter of 28mm which is chiefly used by beverage pro- ducers for carbonated beverages. The diameter is measured at the widest point of the thread. Directly below this is the neck ring which is usually the widest point of the bottle neck. The thread diameter thus does not always allow conclusions to be drawn regarding the size of the bottle open- ing. On a PCO 1881 this is 21.74mm, for example. Looking at the Interna- tional Society of Beverage Technolo- gists (ISBT) website, a scientific and technical society for the beverage industry, one can find countless vol- untary standards these can greatly differ when dealing with still bever- ages compared to hot fill variants, for example. There is also a range of non-standardised models produced by various suppliers. One good exam- ple of how confusing this develop- ment can be is the persistent use of the PCO 1810 which preceded the PCO 1881. There are also reduced and light versions of this type of bottle neck. All of these types of closure have one thing in common, however: they should close the bottle securely and easily, thus the newer standards are using less and less material and growing lighter and lighter. Savings potential According to KHS, in numbers this means that users can reckon on a standard PCI 1881 thread, including the cap, weighing approximately 5.8g. Without the cap this is about 3.7g. Precise figures cannot be given, as Material savings focusing on the bottle neck, thread and cap Lighter preform, lighter bottle The KHS Group keeps finding new ways of optimising containers for carbonated or non-car- bonated beverages, with developers currently focusing on the bottle neck, thread and cap. A number of adjustments enable further savings to be made in this area - without the bottle body sacrificing any of its convenience for the consumer. PREFORM special Neck, thread and cap often offer potential for material savings. Arne Wiese, product manager Bottles & Shapes at KHS