May 14, 2025 14:00

It weighs just 5.89 grams in the U.S. 20-ounce format (591 ml): the Factor 101 PET bottle for still beverages, developed by KHS, the German supplier of blow molding and filling machinery for the beverage industry, in collaboration with injection molding systems specialist Husky Technologies.

Compared to lightweight bottles for still water—which typically weigh around 7 grams on the U.S. market—Factor 101 uses 30% less material. Even more, it can be produced entirely from rPET.

This innovation builds on Factor 100, a feasibility study showcased by KHS at Drinktec 2017: a 500 ml bottle weighing just 5 grams. Since then, KHS has made a series of enhancements, as Fabian Osterhold, packaging designer at KHS, 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 improve the stability of the Factor 101 bottle, the shoulder design was reengineered and functional webbing added to the body. Osterhold and his team also created a “pop-in” base, which flexes inward under vertical load, increasing internal pressure and structural resistance.

This design pushes the top load value to 220 newtons, exceeding the industry benchmark of 200 newtons. “To get there, we also had to redesign the preform,” Osterhold notes. The stretching factor and preform dimensions were re-evaluated, since the length-to-wall-thickness ratio is key during injection molding.

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 molding. In this context, KHS addressed the specifications and feasibilities of the stretch blow molder and bottle design, while Husky made the necessary modifications to the preform.

Beyond bottle geometry, another critical challenge was compatibility with high-speed filling lines, which can process up to 90,000 bottles per hour.

“The main issues here were conveying, labeling and the secondary packaging,” says Osterhold. “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 concludes. “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.”

Photo: Jörg Schwalfenberg

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