In-mold labeling has become widely adopted in consumer plastic packaging applications. In June 2023 however, a toolmaker and automation specialist met at the Technology Days open house at injection molding machinery producer Arburg GmbH + Co. KG and started thinking about which type of advanced and innovative molding technology they could develop together.
They went for in-mold labeling of polypropylene pharmaceutical analysis tubes, resulting in a line running on the Arburg booth at Fakuma 2023, developed in close cooperation between five companies.
Arburg senior application manager medical Sven Kitzlinger told Plastics News while the line was running based on an electric drive Allrounder 520 A Ultimate machine with 150 tonnes clamping force, the IML tubes are produced within 10 seconds cycle time, including "print-to-cut" label alignment to tolerance of 0.2 mm by first robotic laying down on transfer plates, with the associated label adjustment head representing an important part of the automation equipment installed within the production cell developed by Oberengstringen, Switzerland-based Beck Automation AG.
This precise label application is essential, since the label has to show the exact amount of substances placed in the 15 milliliter tubes. A version with thermographic ink printed on the label can show if the temperature drops below 7° C by changing color. The demonstration line doesn't have a clean room environment in the mold area, as it is intended for existing ISO Class 7 clean rooms.
Kim Blondeel, business development manager at Maldegem, Belgium-based IML label producer MCC Label, stressed precise label alignment of the 57 µm thick labels as much tighter than the 1.0 to 1.5 mm tolerance applied with packaging applications. She also pointed to various advantages of applying PP IML labels to PP tubes: a single-stage process, alcohol and scratch resistance and easy recycling of the PP mono-material solution.
Johannes Strassner, managing director and chief sales officer at Neuhausen am Rheinfall, Switzerland-based mold maker Kebo AG, which has been active in IML applications since 1984, in paper at the time, added "the PP label stabilizes the tube wall, so some material can be saved by designing a thinner wall for a given required stiffness."
Strassner says the line on the Arburg booth, equipped with an 8-cavity Kebo mold, is "a proof of concept to get people thinking of having a new experience — and to gain from the high flexibility, functionality with track-and-trace coding, logistical and cost advantages provided by the single-stage process." Systems can also be built to include screw cap application and bag packaging, all within one line, Strassner added.
Ralf Ziemer, sales manager medical at Beck Automation, said Beck has also been active in IML since the mid 1980s, claiming it was Beck's owner who made IML ready for series production, as first shown on a pail molded at a K fair. Beck claims meanwhile to have become one of the top three IML automation specialists in the world.
"We are now standing today with the medical industry where we were earlier in packaging," Ziemer said. "We want to give the industry a big impulse, to show the technical possibilities. It has great potential in the pharma industry."
Among other things, he says, such tubes are really easy to recycle, not only as they are in a PP mono material, but as there is no need to deal with separating labels and adhesive, with associated manual handling costs. "You have to look at the total costs of ownership," he adds.