South Plastic Industry, a leading Asian manufacturer of thermoformed plastic food packaging, has been striving to develop a clear, anti-fogging polypropylene (PP) lid for its microwaveable food packaging. The aim has been to replace oriented polystyrene (OPS) in this key application, but it wasn’t easy to find a way to get the highly recyclable PP to meet all the necessary performance requirements while also retaining the clarity and non-yellowing aesthetics that are vital to appealing to consumers on the grocery store shelves.
Based in New Taipei City, Taiwan, South Plastic Industry (or SPI) has leveraged its close, five-year working relationship with additives supplier Milliken & Company to achieve its goals finally.
Using Milliken’s Millad NX 8000 clarifier, the two parties have produced an UltraClear PP resin that delivers on all the performance promises for ready-meal packaging while also offering additional processing benefits. SPI also recently began using Milliken’s Hyperform HPN performance additives in its PP formulations.
“By using Milliken’s additives, we are able to thermoform our products at a lower processing temperature, which allows us to reduce our energy use,” said Tosho Wang, President of SPI. “At the same time,” he said, “These additives allow SPI to produce a thinner PP lid without affecting rigidity, which in turn helps to reduce plastic usage while increasing output.”
Milliken’s additives to reduce yellowing and oxidation reaction of packaged products
Saving energy during processing is a major plus for SPI, which runs dozens of thermoforming machines in its Taiwan plant. “Milliken’s additives produce an UltraClear APP that prevents yellowing, reduces oxidation reaction, and extends the shelf life of packaged products,” added Kua Cheng Huat, Milliken sales manager for Taiwan. But its crystal clarity is one of the most important features.
Many suppliers use oriented PS resin for their ready-meal packaging lids, but those can only withstand 85°C temperatures and are unsuitable for microwaveable products. With UltraClear PP, such packaged foods can go straight from the refrigerator to the microwave while retaining the necessary clarity and aesthetics.
SPI, which now uses Milliken clarifiers in all its UltraClear PP packaging products, says it plans in the future also to explore using the material to expand the use of PP in more food applications, including some that currently use PET. When it comes to thermoformed polypropylene food packaging for South Plastic Industry, the way forward is clear and involves further close collaboration with Milliken.