PETpla.net Insider 07+08 / 2010

CAPPING / CLOSURES 28 PET planet insider Vol. 11 No. 07+08/10 www.petpla.net Short, light and eco-friendly Light weighting in PET bottles is a very strong trend. The strongest emphasis may be on lower costs through reduced use of raw materials but the same objectives help environ- mental priorities as well. Reduced weight, maintained performance Corvaglia, which is based in Esch- likon, Switzerland, started to look for cost control through material reduction by researching and developing short necks in 2003. It developed the ‘PCO Corvaglia’ standard, also know as CSN-28, which achieved the objec- tives of using less material for the cap and bottle neck, without compromis- ing performance, whether in still or CSD beverage packages. The design was refined in a joint development programme, undertaken with Nestle Waters Italy. Corvaglia’s PCO neck design is unusual, because it does not alter the distance between the neck ring and the tamper band. This has an advantage, to bottling companies in particular, because existing grippers can be used, without amendment, on many filling lines. A second attraction has been that the PCO Corvaglia cor- responds to the widely-used 26.8mm Alaska design which enables PCO Corvaglia and Alaska specifications to be processed on the same filling lines, without adjustment or time-consuming changeovers. (Fig.2) While the amount of material that can be saved per individual cap looks small, at just fractions of a gram, the gains on neck design also contribute to overall savings. Corvaglia worked with a vertically-integrated North American mineral water company that produces around seven million bottles a day to develop a customised closure system for its 500ml bottle. The cap weight was cut by less than two-thirds of a gram; the neck weight reduced by a little under half, from 3.15 to 1.75g. (Fig.3) All these small gains add up to something very much more signifi- cant. Millions of bottles a day rep- resent significant savings in PET and PE material. Each tonne of PET The drive for reduced material consumption also applies to closure systems, an area in which Swiss company Corvaglia has developed a number of solutions. The immediately obvious way in which PET closure system manufacturers have driven to reduce consumption of the thermo- plastic melts used in caps is to cut their size. While a series of ‘short- neck’ designs have appeared over the past years, in the second part of the decade, the International Society of Beverage Technologists (ISBT), which included beverage companies like Coca-Cola and Pepsi, developed the PCO 1881 standard. The use of the word ‘standard’ may be a bit of a misnomer, as approaching 20 different PCO 1881 specifications have been released since then. While PCO 1881 seems likely to become the globally- adopted standard, progress seems to be taking longer than originally antici- pated.(Fig.1) Fig. 1: PCO 1881, 3.75g left PCO 1810 5.20g right Fig. 2 CSN-28 left compared to Alaska 26.8 right Fig. 3 Customised Neck 1.75g left and 3.15g standard neck right Fig. 5 Special closure design for Y-Water