Polymer Additive Technologies at NPE2015 Push Packaging Limits

At the NPE2015 plastics expo this week in Orlando, Milliken & Co., a company that specializes in property-enhancing additives for polymers, showing two products that are expected to have a major impact on respective markets. One is a new version of a polypropylene (PP) clarifier that improves the transparency of an innovative injection molded food can; the other is a polyethylene (PE) nucleator that allows a 30 percent downgauging of bottles for over-the-counter (OTC) aspirin and other pharmaceuticals.

As reported previously, the clarifier, Millad NX 8000, a nonitol-based material, achieves high transparency in a PP food packaging can developed by injection molding machine maker Milacron. Milacron is exhibiting Klear Can, a co-injected PP structure with a core barrier layer of ethylene-vinyl alcohol, at NPE.

"This is the first time we have seen this kind of clarity in a PP can," said Cristina Acevedo, global product line manager for Milliken's plastics additives business.

The key to high transparency is doubling the clarifier loading in PP to 4,000 ppm. Milliken says this produces "optical clarity comparable to glass-like polymers such as polycarbonate, crystal polystyrene and acrylics." The Millad NX 8000 clarifier dissolves in PP prior to injection molding. The clarifier has good solubility, which allows a high matrix loading and improved dispersion in the resin. The high loading also reduces the size of the crystals in PP, improving clarity.

Acevedo says Millad NX 8000 is the only commercial clarifier with such high solubility in PP.

The company is promoting the clarifier for other PP applications like sports-drink bottles, thermoformed cups and clamshell food packages, detergent bottles, closures, and storage containers.

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Meanwhile, the company's PE nucleator, Hyperform HPN-20E is not a new material, but it's said to be effective in a new application: injection blow molded PE bottles. Reed Walker, Milliken's business development and marketing manager for the plastics additives business, says the nucleator permits significant downgauging of bottles by improving barrier properties. "Oxygen and moisture transport decline by 50%, and as a result bottles achieve the required shelf life -- one to two years for OTC pharmaceuticals -- with a thinner gauge," he said.

The initiative to use the nucleator to downgauge bottles came from an undisclosed drug company customer that saw it as a way to promote sustainability.

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HPN-20E is an organic salt used in PE at a conventional loading of 1,000 ppm. The primary market for the additive prior to OTC pharma was closures for water and soft-drink bottles. The nucleator was added to pigments for its ability to achieve color consistency.

Walker says the nucleator can also be used in barrier films to improve shelf-life properties and downgauge structures.

Pat Toensmeier has more than 30 years of experience writing for business-to-business publications. His main areas of coverage have been defense, design, manufacturing, technology and chemicals, especially plastics and composites. He has reported extensively on developments in these areas from the U.S. and Europe, and covered industry events as well in Brazil and Asia. Toensmeier has held various positions at major publishers such as the McGraw-Hill Companies and Hearst Corporation. A graduate of the University of Missouri, he is a contributing editor for several print and online publications. Toensmeier is based in suburban New Haven, Conn.