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The ability to recycle polyethylene naphthalate couldn't have come at a better time, because commerical applications for PEN are beginning to pop up in the packaging marketplace.

Houston-based Shell Chemical Co.'s Hipertuf polyester resin focuses on PEN's attractive packaging properties, such as a better barrier and hot-fill temperatures. Because of its cost, Hipertuf is expected to serve medical and specialty food and beverage markets.

``In the near term, niche markets like medical packaging and retort applications will use [the homopolymer],'' said Bob Minney, manager of recycled programs for the polyester business at Shell Chemical. ``In the longer term, the niche homopolymer will see more widespread use in consumer packaging.''

Israel's Gan Shmuel Foods Ltd. is using Hipertuf in its 1-liter bottles. The hot-fill juice bottles are marketed in Europe and use less than 10 percent naphthalate.

Other products are being tested or can be found on grocery shelves. A field test in Uruguay is of a returnable/refillable 1.5-liter PEN water bottle introduced by Montevideo Refrescos SA, a bottler for Coca-Cola Co.

Dimethyl-2, 6-naphthalene dicarboxylate (NDC) is used in 1.5-liter bottles of Lemon Squash marketed by Fujiya, and 1.5-liter bottles of a grape drink marketed by Asahi, in Japan. Low levels of PEN are used to screen out ultraviolet light, to extend the shelf life and protect the juices.

Hot-filled PET/PEN half-liter bottles of Sports+Fit beverages are marketed by Migros, a huge retailer in Switzerland. The bottles, 8-10 percent naphthalate, are blown using a PET/PEN copolymer by Hoechst Trevira GmbH & Co.

However, one application of PEN that many are watching closely is beer packaging. Toronto-based Pet-Pak introduced a beer bottle made from PEN at Bev-Pak '97, held April 14-15 in Fort Lauderdale, Fla. The material, called Kalidar, is made by ICI Polyester of Wilmington, Del. The bottles are filled with Rockford Red Ale, brewed by Rockford Brewing Co. in Wilmington.

``PEN's superior vapor barrier, resistance to oxygen transmission, chemical resistance and thermal properties make it well suited for applications in small carbonated soft drink, beer, fruit juice or refillable water bottling,'' said John Zucaro, ICI's application development manager for PEN polyesters.

Kalidar is used for films, fiber, extrusion-based processes, engineering polymers, medical packaging and color concentrates as well. ICI invested more than $4 million and converted a production line in its Fayetteville, N.C., plant to manufacture Kalidar. It can produce more than 10 million pounds per year of the material.

``This is a robust polymer,'' said John Carson, market manager for PEN at ICI Polyester.``In Europe's returnable, refillable market, PEN really shines.''

Carson said that PEN bottles can be washed more vigorously and with hotter water. And where PET can have flavor carry-over, PEN does not.

In addition, Kalidex film, a biaxially oriented PEN film made by ICI, is used for a metalized film application. These films are used for shielding and static control and have dimensional stability at elevated temperatures. ICI Polyester is a unit of ICI Americas Inc.