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Europe: Agr manages crystallinity of PET bottles


Agr International, a company in the field of PET bottle material distribution management, said it is commercializing the technology for PET bottle crystallinity management.

The company says it will market it under the trade name CrystalView.

CrystalView will be incorporated into Agr’s Process Pilot automated blowmolder management system and when released, will provide the means to produce polyethylene terephthalate (PET) bottles with consistent crystalline structure while maintaining desired thickness distribution, says CTO Georg Wolfe.

“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,” he said of manufacturing carbonate soft drink bottles using the cold-mold process at an industry conference.

“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,” he said.

The CrystalView process provides stronger, better performing containers and enables the bottle producers to further light-weight with minimal risk.

Data from the experiments or 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 pointed out that adjusting crystallinity is only part of the equation.

The process objective to adjust crystallinity while maintaining proper material distribution is almost impossible without the assistance of technology.

“Agr’s Process Pilot blowmolder management system precisely controls and maintains material distribution at a specified thickness to within ~0.0025mm.” he said.

“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 significant, especially with the push to take light weighting to the limits.

The benefits are considerable.

“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.

Agr’s Process Pilot automated blowmolder control system manages the blowmolder based on direct bottle measurements, on every bottle produced.

By controlling the blowmolder based on direct feedback from bottle measurements rather than just blowmolder performance indicators, the Agr system can ensure that the final product has the desired quality and performance attributes in spite of environmental, blowmolder or material variations that occur during the production process.