KHS and Husky Technologies hail benchmark PET bottle using 30% less material
By creating one of the lightest PET bottles for still beverages, KHS is claiming to set a new standard in bottle making.
A container that utilises only 5.89 grammes of material to carry 591 millimetres of product has been created under the working title of Factor 101 in close collaboration with Husky Technologies, the Canadian manufacturer of injection moulding technology equipment and services. This is comparable to the typical 20-ounce size found in the US.
At drinktec 2017 KHS presented its Factor 100 concept as a feasibility study that featured a PET bottle weighing approximately five grams with a capacity of 500 milliliters. A number of optimisations have now been made to the further development, as KHS packaging designer Fabian Osterhold in Hamburg explains: “With such extreme lightweighting, what’s known as the top load is especially important. This value tells us how sturdy the bottle is from a vertical perspective. It determines whether the container can be stacked or not and survive transportation undamaged.”
To increase stability, the shoulder design of Factor 101 has been modified and the bottle body reinforced with functional webbing. Osterhold and his colleagues have developed a base with a pop-in effect. Here, the base pops inwards to a certain degree when a top load is applied, increasing the internal pressure and therefore the stability of the bottle.
Two hundred newtons is a common top load threshold in the industry; at 220 newtons, the Factor 101 exceeds this. In order to achieve this high value for a PET bottle used for still beverages, adapting just the container shape wasn’t enough.
“The preform design also needed to be developed further,” emphasises Osterhold. This is why KHS joined forces with the specialists at Husky. The company has a wealth of expertise as the world’s leading equipment supplier of PET preform injection moulding systems and services and has been in cooperation with KHS for many years.
Technically speaking, the stretching factors from blank to bottle and the resulting preform dimensions were especially important. The relation of length to wall thickness is particularly relevant to injection moulding. KHS addressed the specifications and feasibilities of the stretch blow moulder and bottle design, while Husky made the necessary modifications to the preform.
“The focus here was on the exact profiling of the preform made possible by KHS technology,” Osterhold ascertains. “Focus lamps in the heater on our InnoPET Blomax Series V, for example, make for extremely precise temperature profiling directly under the bottle neck ring. This ensures that no material stays unstretched. In turn, this considerably reduces the amount of plastic used.”
Compared to the standard lightweight PET container holding 500 milliliters of still water that usually weighs seven grams on the US market, the joint KHS/Husky product requires 30% less material. It can also be manufactured entirely from rPET. However, bottle geometry is just one factor.
“Line compatibility in the high capacity range of up to 90,000 bottles per hour was a key challenge,” says Osterhold. “The main issues here were conveying, labelling and the secondary packaging. In the shrink tunnel, for instance, special attention had to be paid to the bottle shoulder – and the bottle of course shouldn’t fall over during conveying.”
“Not only the weight but also the time in which the project was implemented are possibly record-breaking,” Osterhold states. Thanks to the great teamwork between Husky and the many KHS departments involved in the development process, the project was successfully concluded in just four months.
