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Amcor PET Packaging Finds Success With New 2.5 ounce Hot Fill Bottle

Amcor PET Packaging has created an industry first with the introduction of a new and unique 2.5 ounce hot fill PET container. Natural energy drink industry leader Steaz successfully launched the Steaz Energy Shot earlier this year and the response nationwide has been nothing short of sensational.

Amcor ingenuity and engineering was required to create this one-of-its-kind mini bottle that is available in 12 count cases. Steaz Energy Shot is a convenient and healthy way to build stamina and sustained energy with 150 mg of plant-based caffeine. The all-natural ingredients include organic, Fair Trade Certified™ green tea, Sambazon’s acai juice, Guayaki’s yerba mate, organic berry flavor and organic guarana from the rainforest. The bottle is produced at Amcor’s state-of-the-art facility in Nicholasville, Kentucky.

Amcor has long been the leader in hot fill engineering and the foundation for development of this project was based on proprietary technology that Amcor has developed over the years. The entire package is 100 percent recyclable and although the 2.5 ounce bottle is a relatively simple cylindrical shape, adapting technology used in larger containers was not a straightforward reduction process. Every size container and each design nuance impacts PET performance and presents new challenges.

“As far as we know, there was no heat set container this small on the market before,” said Amcor Principal Engineer - Innovation Kirk Maki. “Perhaps the most difficult part was getting heat set properties into a bottle this size. Vacuum control in hot filling and cooling is the other critical issue, which also required considerable manipulation.”

Controlling the process in process control

From the start, Maki knew the standard process would require a change so many hours of upfront testing and engineering was devoted to the design. “We had to take a step back and determine how to get the process control we needed on a much smaller container. In theory, 2 over 1 equates to 10 over 5, but in practice it is very different.

“First, we had to modify our equipment and add specialty machine controls. We had to downsize and modify the tooling to create a scaled down version of how we would normally process the container in order to drive heat set properties to a level high enough to prevent deformation under the heat. We accomplished what we set out to do. The heat set testing has come back at levels equal to or better than some of our other larger heat set containers,” Maki said.

Maki acknowledged there were challenges with the overall bottle design relating to vacuum control. Testing and calculations based on container diameter were run upfront to ensure that specialty paneling wouldn’t be needed. The paneling was fine when initial hot filling and cooling trials were run, but “the panel rib design had issues. Nothing critical, but we felt it just wasn’t quite right,” Maki said.

So the team continued the quest for perfection by modifying the rib portion of the design. In the process, they developed a superbly smooth area of labeling. “If you make a container that looks good with a wrap label, it will look great in a shrink label,” Maki said.

The mini bottle’s finish area added to the complexity. Whereas the standard finish recalls an earlier PET era, it is not the kind of heat set finish one typically finds on a store shelf today. A wide mouth, 28 mm finish is considered a natural sized opening to drink from, compared to the 20 mm finish on energy drink bottles that have drawn criticism.

“When you have a relatively large 28 mm opening on a 2.5 ounce container, compared to a 43 mm opening on top of 500 ml bottle, you can’t simply transfer technology,” revealed Maki. “Although not as light in weight as some newer designs, it has a versatile finish. What allowed us to use it here is the fact that the bottle is small, so there is relatively little heat capacity.”

The closure itself is a standard design, borrowed from pharmaceutical packaging for this beverage application. It also takes custom equipment to fill these small bottles. Not many fillers are currently set up to do it because there hasn’t been a demand for hot fill in bottles this size until now.

“We know it’s a little difficult to maintain the heat when filling small containers while also maintaining throughput,” said Chris Curtis, Amcor PET account manager, North East. “Most of the hot fill in the industry has been with much larger containers.”

New healthcare beverage targets nutrition issues

The 2.5 Steaz Energy Shot is fortified with B vitamins and is rich in antioxidants like Vitamin C. Like all Steaz products, it is Fair Trade Certified™, USDA Organic, and Vegan certified and contains no artificial preservatives or sweeteners. “People are on the go like never before and they need a healthy, natural fuel for their busy lifestyles,” said Eric Schnell, co-founder of Steaz. “We are excited that Steaz Energy Shot provides a convenient and healthier way to immediately increase energy, stamina and focus without a bunch of artificial ingredients and synthetic caffeine.”