While the blow molded PET bottle is very much part and parcel of the beveragesector today, for some time it has also been growing in significance in the foodindustry, too. The challenge here is that food is usually packaged in wide-neckcontainers which have to be manufactured on special equipment provided by thesystems supplier. For converter Gateway Plastics, Inc., from Wisconsin (USA) KHShas now made it possible to process preform necks of up to 70 mm in diameter onits rotary Blomax 10 SW. This is the first machine of its kind.
Wide-neck PET containers are suitable for packagingmayonnaise and peanut butter, tomato sauce or gratedParmesan cheese. On the one hand they have all the classicadvantages of PET, such as non-breakability and a lowweight, yet they are also slightly more expensive to producethan normal PET beverage bottles due to their larger andheavier neck. It is thus all the more important to reduce thesecosts. Converter Gateway Plastics, Inc., from Mequon in thesoutheast of the US state of Wisconsin has now taken a largestep towards doing so. The company was founded in 1970 andsoon specialized in the plastic injection molding of customizedplastic packaging. As a converter Gateway Plastics designsand produces packaging at facilities covering over 26,000m2, also managing the logistics to the bottler. Its products arecurrently used in the food, pet food, dietary supplement andchemicals sectors. The company also makes its own preformsfor the stretch blow molded PET bottles.When looking for ways to improve its operations, GatewayPlastics also contacted KHS to talk about using the stretchblow molders established in the beverage industry in theproduction of wide-neck containers. Until just recentlytwo linear machines from a KHS competitor stood in theproduction shops; they are now no longer there. Kyle Kopp,engineering manager at Gateway Plastics, explains to KHS:“The machine we needed simply didn’t exist. KHS rose to thechallenge, however, and supplied us with a quality machine.”In August 2016 the first rotary stretch blow molding machinefor wide-neck PET bottles was installed at the factory and hasbeen running without unplanned stops ever since. Its capacityof up to 15,000 containers per hour is one of the highestoutputs for this type of machine worldwide. The manufactureof the machine itself proved something of a challenge for thesystems manufacturer from Dortmund, Germany, however.
DEVELOPED ON THE BASIS OFESTABLISHED TECHNOLOGY
The larger neck diameters are theoretically not a problemfor a classic stretch blow molder as the stretch blow moldingprocess functions as for normal PET bottles. At second glance,however, there are a number of special characteristics to betaken into account. First of all there are the preforms. Dueto their larger necks these require adapted sorting and neckhandling so that they can be safely and reliably conveyedthrough the entire process. Once this has been achieved,engineers must then ask themselves how the preform can beheated in the heater box without the neck also becoming toohot and deforming. To this end KHS designed a special heater.With this the manufacturer is not only able to process a certaintype of wide-neck preform but also a whole variety of the sameon site without the need for mechanical changeovers. Thisparticular construction, in which special reflectors beneaththe neck ring protect the neck, is registered as patent pending.It is this specific system which enables the wide-neck preformsto be blow molded on the rotary machine at such a high speedas yet not achieved by any other manufacturer. This version ofthe InnoPET Blomax Series IV is not a one-off. The Blomax 10SW may be the first of its kind but it’s by no means the last. Intheory we can offer every customer an output of around 1,650bottles per station and hour. With ten stations, as at GatewayPlastics, a rate of up to 16,500 bottles per hour would thuseven be possible – thus beating the new record just set.
EFFICIENCY FOR A GROWING MARKET
The technical tricks in themselves are of course not necessarilya mark of value for the customer. “What’s important for us isthat we can supply parts of a high quality and at the same timeboost our performance and efficiency,” says Kopp. The newlines work more efficiently and thus consume a lot less energyper container than Gateway Plastics previously had to invest.The distribution of materials during the stretch blow moldingprocess has also improved. The top load – the maximumvertical force which can be applied to a PET container beforeit deforms – could also be increased.The convincing result is also the outcome of closecoordination between KHS and Gateway Plastics. KHS wasable to implement all of the requirements made by theconverter, including machine development, inside of a year.Just around 11 months after the order being placed in July2015 the new machine left the KHS Corpoplast productionshop in Hamburg in Germany. Since commissioning in Augustthe machinery has run without stopping – well worthwhile forGateway Plastics as the market for wide-neck PET containersis growing worldwide. In North America in particular more andmore food in the medium to high price segment is movingfrom glass to the PET bottle. Consumer acceptance is high.In the future the potential customer base could even beextended; in combination with FreshSafe PET® coatingtechnology from KHS Plasmax especially sensitive foods arealso no longer a problem for plastic containers. A protectivelayer prevents oxygen from getting into the PET container andstops valuable ingredients from getting out. The use of coatingtechnology and possible blocking of the two machines is ofcourse also feasible for wide-neck PET. After the adaptationsmade to the high-performance rotary machines in this sector,this would be a comparatively minor challenge.