Friedrichshafen, Germany — Swiss injection molding machine builder Netstal Group and its partners have designed a package with reduced plastic content for keeping food like yogurt, cheese, ice cream and salads.
The collaboration between eight companies resulted in a round pail with a paper chassis for German packaging manufacturer Spies Kunststoffe GmbH.
Produced with a Netstal Elion 2200-1000 injection molding machine, the pails consist of a polypropylene rim and skeleton with a wall thickness of 0.92 millimeters bonded to a PP-coated cardboard band.
"The cardboard band serves not only as an outer cover but also takes over the protective function of the contents through the coating," Michael Birchler, head of marketing and communications, said in an email.
During production, a pre-printed band of the coated cardboard is inserted into the two cavities of the mold using in-mold-labeling (IML) robotics.
PP is then injected via channels to fill the rim of the bucket and firmly bond it to the cardboard band.
The material also fills the skeleton, which has a wall thickness of 0.92 millimeters in the area of the flow bars and is made in the same injection molding process as the rim with a cycle time of five seconds.
PP is used for the cardboard coating, too, to ensure durability of the contents and tightness. The package also has plastic seams.
With this application, Netstal and its partners created a novel 1.2-liter pail with minimal weight and maximum content of renewable raw materials, Birchler said. The amount of plastic used is reduced and replaced with coated cardboard, he added.
When asked about the recyclability of coated cardboard, Birchler said, "After consultation with the German Recycling Paper + Cardboard Association, even if the product is sent to the carton collection, it is sorted out for thermal recycling. If there is an existing recycling stream for Tetra Paks in a country, the plastic can be separated from the cellulose by remaining in a water bath for a longer period of time."
Tetra Pak, part of Swiss-based Tetra Laval Group, is a food processing, packaging and distribution company for dairy products, beverages, ice cream, cheese, vegetables and pet food. The business is focused on reducing the use of all raw materials and energy during manufacturing and distribution.
In addition to Spies, Netstal partnered with Muller Technology Conthey, Motan Colortronic, EF Cooling, Sabic, Stora Enso and Engelhardt Etikett.
Some of the partners helped automate the process. After a camera check for quality, robots remove the finished pails and stack them on a conveyor belt. The stacks of pails are then packed into boxes by a collaborative boxing robot.
Birchler summed up the automation like this: "There will be the main linear robot for the IML and takeout process followed by a six-axis robot who will process the vision inspection (reject of bad parts if necessary) and stacking of the pails. A cobot will be occupied with boxing of the stacks into provided trollies."
The partners are producing the pails with a Elion 2200 press to reliably reproduce the fine structures of the skeleton with shot weight consistency and controlled injection performance.
The machine has a hybrid injection unit and double valve technology.
The flow path and wall thickness ratio of the pail application is 1:305, which requires very high injection dynamics.
Also, plasticizing was designed to ensure optimum color homogeneity.
Looking ahead, in January 2022, Netstal will offer ISO 17025 accredited calibration of injection molding machines, which is needed regularly by medical molders. Trained calibration personnel will guarantee measurement accuracy of the relevant sensor signals within a defined range.
Netstal has fulfilled the certification criteria as an accredited laboratory, according to ISO 17025. The certificate is expected to be issued by the Swiss Accreditation Service by the end of the year.
"Netstal will then be considered an accredited laboratory and will be able to offer ISO 17025 accredited calibrations to its customers," Birchler said, adding the service is subject to a fee.
Netstal also is promoting its free e-service document repository for customers, which is offered as part of its so-called Life Cycle concept.
The company has been offering its own online service portal since 2018.
The repository it includes eliminates the need to search for specific machine documents. The platform provides access to electrical diagrams, technical data and setting instructions.
Quick identification and ordering of spare parts is possible, too, by an integrated 3D spare parts catalog with graphic visualization of the individual machine components.
Also, service support can be requested through a simple ticketing system.
Netstal builds injection molding machines with clamping forces between 80 and 1,000 tons for the packaging, medical and beverage markets, including PET-Line-brand preform systems for up to 144 cavities.
Based in Näfels, Switzerland, since 1961, Netstal employs more than 500 people worldwide. The company, which is certified for ISO 9001, has been part of the KraussMaffei Group since 1992.
Do you have an opinion about this story? Do you have some thoughts you'd like to share with our readers? Plastics News would love to hear from you. Email your letter to Editor at [email protected]
Please enter a valid email address.
Please enter your email address.
Please select at least one newsletter to subscribe.
Staying current is easy with Plastics News delivered straight to your inbox, free of charge.
Plastics News covers the business of the global plastics industry. We report news, gather data and deliver timely information that provides our readers with a competitive advantage.
1155 Gratiot Avenue Detroit MI 48207-2997