Agr International Inc. (Butler, PA) has recently announced that it is currently working on commercializing the technology for PET bottle crystallinity management, and will market it under the trade name “CrystalView." According to Georg Wolfe, Agr’s Chief Technical Officer, CrystalView will be integrated into Agr’s Process Pilot automated blowmolder management system and when released, will provide the means to produce PET bottles with consistent crystalline structure while preserving the desired thickness distribution.
During a recent industry conference, Wolfe gave an update on the developments over the past few months. In his presentation, he provided the results from several studies that his team has done on the relationships that affect the crystalline structure of PET bottles as they are produced, using both hot and chilled mold production process.
When asked about the worth of managing crystallinity at a recent event, Wolfe commented that for CSD bottles manufactured using the cold-mold process, “our experiments showed that improved time to stress cracking is a function of the temperature achieved in the stretching process. Time to stress crack improved significantly by maximizing orientation in the cold process.” Additionally, he stated, “By optimizing crystallinity/orientation there was no down side. Our findings showed that bottle performance factors either improved or stayed well within the required performance specifications. The CrystalView process provides stronger, better performing containers and enables the bottle producers to further light-weight with minimal risk.”
“The CrystalView product will take advantage of the extensive knowledge base created over the last two years of our research and development effort,” stated Wolfe. Data from the experiments (DOE) are the foundation for the sophisticated blowmolder control algorithms incorporated into the CrystalView product to actively manage crystallinity within the reheat/stretch-blow process.
Wolfe also added that adjusting crystallinity is just a fraction of the equation. The process objective to adjust crystallinity while maintaining proper material distribution is nearly impossible without the aid of technology.
“Agr’s Process Pilot blowmolder management system precisely controls and maintains material distribution at a specified thickness to within ~0.0025mm. When coupled with CrystalView, we will have the capability to fine tune and control the process to optimize crystallinity and maintain material distribution at optimal levels consistently for every bottle in a complete production run.” This is monumental, especially with the drive to take lightweighting to the limits. The benefits are huge. “If you can actively manage crystallinity and at the same time control thickness, you have much greater control over the bottle attributes that affect performance, especially with very light bottles,” concluded Wolfe.