KHS, in collaboration with Husky, has set an impressive new benchmark by engineering what it is calling “one of the world’s lightest PET bottles for still beverages to date”.
Under the working title of Factor 101, the new benchmark was achieved in close cooperation with Canadian-based injection moulding technology equipment and services provider, Husky Technologies.
Through the partnership, a container had been produced that uses just 5.89 grams of material to hold 591 millilitres of product, which is equivalent to the 20-ounce size common 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 millilitres.
A number of optimisations have now been made to further the development to the current benchmark.
“With such extreme lightweighting, what’s known as the top load is especially important,” said Fabian Osterhold, packaging designer at KHS.
“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.”
Extremely robust lightweight
To increase stability, the shoulder design of Factor 101 had been modified and the bottle body reinforced with functional webbing. Moreover, Osterhold and his colleagues 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, as Osterhold explained.
“The preform design also needed to be developed further. This is why KHS joined forces with the specialists at Husky,” he said.
“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.
Challenging coordination
Technically speaking, the stretching factors from blank to bottle and the resulting preform dimensions were especially important here. The relation of length to wall thickness is particularly relevant to injection moulding.
In this context, 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 added.
“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.”
30 per cent less material
Compared to the standard lightweight PET container holding 500 millilitres of still water that usually weighs seven grams on the US market, the joint KHS and Husky product requires 30 per cent less material, and 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,” said 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.”
High-speed development
“Not only the weight but also the time in which the project was implemented are possibly record-breaking,” Osterhold stated.
“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.”
Factor 101 was first presented live by Husky at the NPE 2024 plastics trade show in Orlando, Florida, in May 2024. The extreme lightweight was met with great interest in the industry.
