MechChem Africa November-December 2022

Packaging, a sustainable society and temperature controllers To solve the social issue of marine plastic waste, OMRON has embarked on the challenging task of developing innovative temperature controllers that will significantly reduce defects when using eco-friendly packaging materials. M assive amounts of marine plastic waste have become a serious problem all over the world. Over eight million tons

of plastic waste enter the ocean every year. If no action is taken, some sources estimate that by 2025, the cumulative volume of plas tics dumped in oceans will be approximately one billion tons, outweighing all the fish in the sea. Plastic waste in oceans not only harms and destroys marine organisms but it also pollutes the seas and eventually threatens human health and lives. To address these concerns, efforts are underway across the globe to reduce the use of plastics. For container and packag ing materials in the industrial sector, many companies are trying to switch from plastic materials to paper and to thinner and/or biodegradable plastics that dissolve in the natural environment. Yet the switch to eco-friendly packag ing materials is not easy because of the difference in thermal reactivity between new packaging materials and conventional plastic. Traditionally, heat is applied to the packaging plastic or adhesive to seal the seams. The problemhere is that paper pack aging materials do not conduct heat well, and thin-walled plastics and biodegradable plastics have very low thermal tolerance. If using conventional packaging ma chines, eco-friendly materials shrink and the heat causes wrinkling, scorching, or melting, resulting in unacceptable defect levels. This has deterred many companies from changing to more environmentally friendly packaging materials. The problem came to the attention of Miho Nishide, who was developing tem perature controllers for OMRON at the Product Business Division HQ. Based on a sincere wish to address the social issues caused bymarine plastic waste, and leverag ing OMRON's technology leadership in this area, Nishide and her team launched into developing new temperature measurement and control techniques. With conventional automatic plastic packaging machines, once the package is filled with product, it is sealed at the mouth using sealing bars heated to a high tem perature. What is important here is to keep the correct temperature on the surfaces

Miho Nishide, temperature controller developer with the Product Planning Team at OMRON Product Business Division HQ.

of sealing bars. If the temperature is even marginally lower or higher, the packaging will be defective. “Our goal was to reduce temperature fluctuation on the sealing surfaces during the packaging process to one-tenth that on conventional machines,” explains Nishide. She soon realised that it was an unexpected ly daunting challenge, even with OMRON's 50-plus years of experience and cutting edge temperature control technology. “Given the sheer variety of materials, thicknesses and number of layers, there are tens of thousands of types of packag ing materials, and it's simply impossible to support all of them. But we didn't start this project because we wanted to enhance the performance or specs of temperature con trollers. Rather, we had an overriding goal of solving the social issue caused by marine plastic waste as a way of contributing to the global community,” she says. “We knew no one else could offer solu tions to this universal issue, and that helped us overcome the emotional conflicts we encountered," she adds. "Before we knew it, we had a circle of

supporters from other departments. Not only that, but customers who had purchased temperature control lers for packaging machines from us were generous enough to educate us on the mechanism of packag ing machines and identifying under which conditions sealing defects occurred on their lines. There were 82 of these selfless customers,” she says. In arriving at a solution, team members read a total of 1 437 pages of academic papers and other reference literature. To advance their knowledge of packaging machines, they installed a flow wrapper machine within the development area to create a complete packaging line, and here they conducted sealing experiments again and again, using over 10 km of packaging material. Finally, they identified the cause of seal ing defects: When sealing bars hold packag ing materials, heat on the sealing surfaces is lost, lowering the temperature. To solve this problem, it was necessary to accurately measure the temperature on the surfaces of the sealing bars. Yet, it was not easy to sense fast-moving bars and simultaneously moni

28 ¦ MechChem Africa • November-December 2022