PETpla.net Insider 03 / 2013

PREFORM PRODUCTION 29 PET planet insider Vol. 14 No. 03/13 www.petpla.net products can be found in Asia, for example, where certain types of tea are sold in bottles that are specifically designed for each harvesting season. This of course results in very short life cycles for the container designed. In this context the question of whether the bottle is intended to be returnable or nonreturnable will be answered. Competitors Identification of competitors and the specific products with which the new container will compete will affect the bottle design. It is hardly useful to develop a product only to dis- cover that it is too similar to some- thing already offered by a competitor. Here, a close cooperation with the customer’s marketing department is required. Product Another key issue is the product for which the bottle will be used. Still or carbonated mineral water, CSDs, beer, fruit juice, tea, or dairy products each require different design fea- tures. Filling process Directly related to the contents is the question of the filling method, which also should be discussed in the very early design phases. Will the contents be aseptically filled or hot filled? Will the bottle be pressur- ised? Will a nozzle be used to spray nitrogen over the contents to eliminate oxygen from the headspace? It is also important to know if and how much the contents tend to foam. Will a long- tube filler or spreader be used? In the latter case, it is important that the contents can flow down the inner wall of the bottle without protrusions that may disrupt the flow. Bottle transport How will the bottles be transported during production? Will the bottles coming from the stretch blow mould- ing machine be transported through the subsequent process stages by an air conveyor or a conveyor belt? Which type of conveyor belts will be used? In addition to rubber mat-top conveyors, gravity roller tables, and articulated con- Please order your copy at the PETplanet insider book shop: https://www.petpla.net/books Bottles, Preforms and Closures A Design Guide for PET Packaging Second Edition by Ottmar Brandau 115,00 € 180 pages © Copyright Elsevier 2012 veyor belts, there are also combinations of the above and special designs, which in turn raise the issue of speed differen- tials within the same conveying system. Apart from the conveying medium, e.g., air conveyor or conveyor belt, the speed of transport has an impact that should not be underestimated. Preform Another key question relates to the preform: Will a standard pre- form be used? Has this already been selected or determined, or will a spe- cial-purpose preform be developed? (Read more in Chapter 2). Shape of the base In some cases the base of the bottle must have a specific shape. In general, the following base shapes are possible, but these are merely given as examples because there are numerous variants:  Multiple-foot base: The most well- known multifoot base is the peta- loid base. Footed bases that are resistant to internal pressure are used for carbonated contents, such as mineral waters, beer, and CSDs, when the internal pressure exceeds 1bar. Apart from the petaloid base, there are many special variants.  Still water base: For still products with no internal pressure, a still water base can be used. Bases of this type use an outer, circular rim on which the bottle rests. The centre of the base is more or less dished internally and ribs may be used to mould a thin but strong base.  So-called champagne bases offer a good resistance to internal pres- sures up to 4bar. This type of base design is characterised by a higher wall thickness in the base area. As a result of the required special pre- forms with a step core design (and a lower output during blow mould- ing), this variant is more expensive and is therefore preferably used in the premium sector and beer.  For hot-filled products, special hot-fill bases are used, which are resistant to the vacuum load cre- ated when the contents cool down. Other points that have to be taken into consideration in PET bottle design are more widely discussed in the book. Briefly, they comprise the following topics:  Mouth/neck/cap  Volume  Markets  Labelling  Transport packaging specifications  Approval procedure  Time frame  Design engineering *This article was published in Bot- tles, Preforms and Closures, Ottmar Brandau, Chapter 1.1., Copyright Elsevier 2012