Ever since foods have been processed and packaged for future consumption, packaging professionals have wrestled with the need to protect these products from oxygen. Oxygen, the stuff of life for us, has a negative effect on such things as product flavor, color and vitamin content.

Over the past 30 years, PET has experienced tremendous growth as many food product categories converted from glass. But, that rate of conversion has been limited by the less-than-perfect oxygen barrier characteristics of ordinary PET.  

There has been a significant push to develop technology to address this challenge, and some of the most interesting work is being done in the area of active barrier materials. These materials, classified as “scavengers”, minimize the permeation of oxygen through the container sidewall by chemically binding oxygen molecules.

Philadelphia-based Constar International has dedicated a significant portion of its R&D efforts to developing solutions in this marketplace, including Oxbar®, a multi-layer oxygen scavenger with reportedly excellent performance. The challenge is that such multi-layer materials require a significant investment in multilayer injection equipment and can suffer from delamination or “bag in a bottle” syndrome, which results when the layers of plastic separate.

Constar has also developed a monolayer scavenger called MonOxbar®, which offers comparable performance to Oxbar but additional cost savings because of its single-layer structure. However, this material exhibits a slight pearlescence and haze, which has pushed Constar to engineer a perfectly clear solution with all the same performance characteristics.

Enter DiamondClear™, a monolayer PET structure that combines superior oxygen scavenging performance with brilliant glass-like clarity.

“With DiamondClear, we have a container that looks as bright and clear as glass—exactly the way a brand owner moving from glass to plastic would want their package to look,” says Doug Robinson, vice president of marketing at Constar. “And we’re able to do that at excellent performance levels and at the same lower relative costs of a monolayer structure.”

According to Robinson, this new technology will be available in 2006.

Oxygen scavenging PET technology. At Constar International Inc., contact Doug Robinson at 215.552.3700 or drobinson@constar.net.