Can PP sub for PET?

Krones claims it has successfully demonstrated that injection-molded polypropylene performs can be stretch blow molded into bottles at 1귔 bottles/hr.

That's just 100 bottles/hr slower than maximum production speed for PET performs on the same Krones Contiform 10-cavity rotary stretch blow molding machine. Dr. Christian Detrois, head of Krones PET Technology Center in Germany, will describe Krones' findings at Nova-Pack Europe 2004, scheduled October 18-19 in Dusseldorf, Germany, and presented by Schotland Business Research.

Historically, the three major obstacles for PP compared to PET have been a narrower processing window, marginally lower clarity, and slower processing speeds. The narrower processing window and clarity issues have been addressed with improved PP resins and/or the use of clarifying agents.

Now, for the first time, the speed issue has been addressed as well. Moreover, the OPP bottles produced by Krones are said to have properties, including clarity, that rival bottles made of PET. In addition, Krones contends that with minor equipment modifications, OPP bottles could indeed be produced on two-stage PET stretch blow molding machines with throughputs that match those for PET.

For more information on attending Nova-Pack Europe 2004, the 17th International Congress on PET Containers for Food & Beverages, visit

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