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New Cyclic Olefins Are Clearly Worth a Look.

* There is a growing family of polyolefins that are nothing like the polyethylenes and polypropylenes familiar to most processors. Cyclic olefin homopolymers and copolymers are engineering thermoplastics derived from the ring-shaped norbornene molecule, which is made from dicyclopentadiene (DCPD) and ethylene. These resins boast glass-like transparency, low dielectric loss, low moisture absorption, excellent dimensional stability, high heat resistance (212-374 F Tg), and high melt-flow rates that permit very precise molding. Cyclic olefins are also being investigated as a blending ingredient to stiffen polyolefin films.

Cyclic olefins are commercially available from a handful of pilot-scale plants around the world. Current world production of these resins is only about 20 million Ib/yr from four suppliers. Three are in Japan (Nippon Zeon, Mitsui Chemical, and JSR Corp., formerly Japan Synthetic Rubber) and one is in Germany (Ticona). As applications multiply, several producers are increasing capacity. At mid-year, Ticona will start up the world's first large-scale cyclic-olefin plant in Germany--66 million lb/yr.

Meanwhile, Bayer AG in Germany has applied for an international patent (No. W098/33830, Jan. 1998) together with Teijin Ltd. of Japan for a new cyclo-olefin copolymer and the process to make it. This product has not been commercialized yet. Both Bayer and Teijin are also large producers of polycarbonate, which is expected to compete with cyclo-olefins in next-generation, higher-capacity DVDs.

Another producer of norhornenebased cyclic olefins is BFGoodrich Performance Materials in Charlotte, N.C. However, its resins are highpriced specialties (up to $3000/Ib) that are non-melting and must be processed from solution. They can have very high heat resistance (Tg up to 700 F) and are aimed at microelectronic applications.

High moisture barrier

Although cyclic olefins are unfamiliar to U.S. processors, the ones they have heard the most about are the Topas family of amorphous copolymers developed by Ticona, whose U.S. office is in Summit, N.J. Until the commercial plant starts up, Topas is made in a 450,000-lb/yr pilot reactor in Germany, and larger quantities are being made by a toll supplier. Topas is already commercial on a small scale in a half-dozen grades used for medical films and bottles, injection molded medical devices, and lenses. Current truckload developmental pricing is $2.65/Ib, which will drop somewhat when the new plant is fully on stream.

The first major commercial application is a five-layer laminated film, thermoformed into blister packs for Bayer Aspirin in Indonesia. The 12mil film has a core of Topas 8007 with a thin skin of PP on either side. Topas is used as a moisture barrier to protect the aspirin from high humidity. Ticona in the U.S. is also developing five-layer coextruded films for extreme moisture barrier. One consists of 15 microns of PP on either side of 240 microns ofTopas 8007, with tie layers in between. It's said to be cost competitive with PVDC-coated PVC.

Topas is also used commercially in a number of optical and medical applications in Europe. Schott Pharmaceutical Packaging in Mainz, Germany (with U.S. offices in Cleona, Pa.), has developed a robotic cleanroom process to injection mold and assemble Topas syringes. [Circle 21]

In pharmaceutical bottles, Topas's high moisture barrier could extend drug shelf life longer than plastics currently being used, Ticona says.

"We also think blends will be a major application for Topas," says Donal McNally, Ticona's U.S. marketing manager for the resin. Adding 10-20% Topas to a 3-mil polyethylene heat-seal layer in a packaging film makes it a great deal stiffer, he notes. "This is under evaluation now by a number of people in the food business for stand-up pouches." At NPE in June, Macro Engineering of Mississauga, Ont., will run blown film of a Topas blend.
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Comment:New Cyclic Olefins Are Clearly Worth a Look.
Publication:Plastics Technology
Article Type:Brief Article
Geographic Code:00WOR
Date:Mar 1, 2000
Words:618
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