PTI Develops First Lightweight Foamed PET Bottle/Jar

HOLLAND, Oh. - Plastic Technologies, Inc. (PTI) has developed the first lightweight foamed polyethylene terephthalate (PET) bottle/jar blow molding process.  Marketed under the oPTISM (pronounced “opti”) brand name, the process is based on MuCell® technology licensed from Trexel, Inc.

The capability will now provide food and beverage brand owners with a broader range of PET container aesthetics and performance capabilities than previously possible.  For example, the process enables white or silvery colored bottles to be made without additives that can limit package recycling.  Containers also have a unique surface feel and provide tactile “traction”, which minimizes slipping.  This process also blow molds details more prominently, which enables decorations, such as embossed logos, to stand out better.

The oPTISM bottle technology provides desirable features for those brand owners looking for a distinctive new visual presence, while at the same time retaining the recycling benefits that inclusion in the clear PET waste stream offers. 

“White oPTISM bottles provide an environmentally-friendly option to conventional bottles, which use additives to achieve a similar tint.  Instead of being a contaminant to the clear recycling stream, white foamed bottles will mold into a transparent bottle after remelting and subsequent processing,” explains Frank Semersky, vice president, PTI. 

In addition to white or silver, blue and green hues also can be used since those color streams already exist in traditional PET recycling.  The technology is also capable of producing bottles in a variety of pastel colors (amber, yellow, pink, etc.). However, these cannot be recycled as part of the clear PET stream.  Containers can be made from slightly translucent to opaque, depending on the desired aesthetics and performance characteristics.

Because the foam process adds stiffness, lightweighting of up to 5 percent is also feasible without significant loss of performance. Further, the technology can produce bottles with significant light barrier characteristics—up to 95 percent reduction in transmitted light. 

PTI’s oPTISM bottle capability is based on using the MuCell® microcellular foam injection molding technology to mold preforms, which can then be blow molded on conventional equipment. The bottles are made in four basic steps:

• Nitrogen is injected into the melt through the barrel on a modified perform molding machine to form a single-phase solution of polymer and gas.
• Foam produced as cavity-fill pressure is dropped below nucleation pressure during the injection cycle.
• Foam cells expand as gas is diffused into bubbles.  Processing conditions are used to control cell growth in the finished preform.
• The preforms are blow molded on conventional, unmodified blow molding machines to produce the foam bottles.

For more info visit www.plastictechnologies.com.