Amcor PET Packaging has created an industry first with the introduction of a new and unique 2.5 ounce hot fill PET container. Amcor ingenuity and engineering was required to create this one-of-its-kind mini package that is dwarfed by its 20 ounce big brother. The bottle, which is produced at Amcor’s state-of-the-art facility in Nicholasville, Kentucky, is being used to launch Hormel Health Labs new “healthy shot™" high protein healthcare beverage.
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. 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 project engineer 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 up-front testing and engineering was devoted to the design. “We had to take a step back and determine how we were going 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 up-front 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.
Breaking the mold, literally
Maki said the mini bottle’s finish area added to the complexity of this project. 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.
“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 it is 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’s 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
Hormel Health Labs focuses primarily on specialty products for hospitals, nursing homes and rehabilitation centers. One of the primary concerns in nursing homes is weight loss among aging patients who do not consume enough protein. Many patients usually drink only half or less of an 8 ounce milkshake type product that contains 9 grams of protein. With the new Amcor PET bottle, Hormel can pack as much protein as possible into a very concentrated package that is sized right for patient consumption.
Dubbed “healthy shot”, the high powered fruit flavored drink being introduced soon packs a full 12 grams of protein into those 2.5 ounces, and no less than 24 grams into its double protein 2.5 formulation.
Amcor PET Packaging is the leading manufacturer of PET (polyethylene terephthalate) plastic packaging for the global beverage, food and non-food industries with 60 facilities in 12 countries. Its parent company, Amcor Limited, offers a broad range of packaging solutions and ranks as one of the top three packaging companies in the world. Amcor’s extensive operations include 217 plants in 34 countries. It is headquartered in Melbourne, Australia and, for the fiscal year ending June 30, 2008, reported sales revenues of $8.3 billion (U.S.).