ELK GROVE VILLAGE, ILL. — Aoki Technical Laboratory Inc. has patented technology for a PET bottle molded from a preform with an integrated, hinged handle.
Two handles fan out horizontally from the neck area of the preform. Once the bottle has been blow molded and filled with a product, the handles bend into an upright position for easy carrying.
Aoki officials introduced the technology, used on a 10-liter bottle, during a news conference June 25 at Aoki's U.S. headquarters in Elk Grove Village. The handle can go on any size of container, but the real advantage comes on bigger packages that are hard to carry, they said.
What is packaged in PET bottles of 10 liters — about 21/2 gallons? Strong early markets include cooking oil and bottled water, said Teruo Sakai, managing sales director. In some countries, such as Spain, Italy, Greece and Portugal, consumers buy large quantities of oil.
Aoki officials think other markets should open up as word spreads about the bottle. For example, one company has started packaging liquid laundry detergent in a 10-liter bottle.
Competitors of Aoki already offer a system of handles for PET bottles, but they typically are injection molded from another resin, Sakai said. That adds cost for extra equipment to attach the handle and it makes the bottles harder to recycle, he said.
``The point is, this time, the handle and bottle are integrated in one structure. That's a very important point,'' Sakai said.
Aoki's U.S. patent on the technology for the handled PET bottle — No. 5,862,929 — was issued Jan. 26.
Setsuyuki Takeuchi, one of the inventors, said molecular orientation of the PET resin gives the handle impressive strength, allowing it to hold the filled bottle even as the handles are flexed upright at a 90-degree angle. As the material is forced through a narrow living hinge, molecules become highly oriented, said Takeuchi, Aoki's managing director for technical development.
At the news conference, Aoki officials said the bottle is well-suited to their company's one-stage process, which injection molds preforms, then shuttles over to a blow molding station, all within the same machine. An Aoki machine can turn out 10-liter handled bottles at a rate of 140 an hour, or 760 5-liter bottles an hour, Sakai said. Aoki has built a special, large machine to turn out 10-liter bottles.
Sakai said the large, handled bottle would be very difficult to manufacture using the two-stage process, which molds large numbers of preforms.
Aoki also revealed another new PET bottle design, with a snap-fit, injection molded polypropylene handle. The handle fits onto the side of a bottle, similar to extrusion blow molded bottles of PP, polyethylene and PVC that sport molded-in handles.
Takeuchi said other companies are making PET bottles with side handles by inserting the injection molded handle into the blow mold. But that can cause leaks in the finished container, he said.
With Aoki's process, a robot snap-fits the handle onto a completed bottle, which is designed to fit precisely with the handle. Aoki makes a mechanism inside the mold that forms notches in the molded bottle.
Sakai said Aoki has sold one of the side-handle machines to a Taiwanese customer that switched from PVC to PET. A consumer easily can twist and remove the handle to recycle the bottle.
One huge market — soda bottles — is likely to remain untapped by the Aoki technology, company officials said. Soft drink manufacturers say they want 2-liter PET bottles with a handle. But Sakai said they demand huge output better suited to the two-stage process instead of Aoki's single-stage machines. He also cited a technical challenge caused by pressure inside the bottle from carbonated beverages. The pressure causes the bottle to flex, so the handle may not fit right, he said.
Nagano, Japan-based Aoki opened the U.S. headquarters in Elk Grove Village last year.