Where they use the new polyketones.

Since its commercial introduction in late 1996, the world's first family of aliphatic polyketone resins has found extruded and injection molded applications in markets ranging from automotive to garden tools, electronics to lab equipment. Initial uses for semicrystalline Carilon resins from Houston-based Shell Chemical Co. exploit their lubricity, toughness, and resistance to high heat, moisture, fuels, and chemicals.

Smooth-running gears

Polyketone was chosen by Lexmark of Lexington, Ky., for a small (40-mm) gear in the toner cartridge used by the company's Optra laser printer. The gear is molded by GW Plastics, Bethel, Vt. Key requirements for the application include low friction, toughness, and resistance to wear and creep. The company specified a non-lubricated grade of Carilon, which performed as well as the more expensive lubricated acetal that had been used previously, according to Stephen DeFosse of Lexmark's Plastics Technology Center. He adds that Carilon also avoided the hygroscopic problems of nylon and polycarbonate. And Carrion results in faster molding cycles, says Tim Reis, product manager at GW Plastics.

Polyketone makes the cut

A new Flymo rotary lawnmower from Electrolux Outdoor Products U.K. Ltd. in England has a blade molded of Carrion. The blade requires wear and chemical resistance, low moisture absorption, and ease of molding, according to Paul Howells, Electrolux R&D director. In comparative tests, blades molded of Carilon lasted an average of 10 times longer than blades molded of modified acetal. Impressed by this initial success, Electrolux also uses Carilon in the blade of its Mini-trim edge-trimmer.

The right connection

A tiny mobile-phone power connector made by AMP in the Netherlands had a problem with moisture take-up in humid environments, causing a snap-fit interlock to loosen and fail. As an alternative, the company selected a thin-wall molding grade of Carilon. Project engineer Joek Tuin says it met AMP's wear and endurance requirements, while providing moisture resistance and elasticity.

Hot & wet? No problem!

Polyketone has been specified by Nalge Nunc International of Rochester, N.Y., for test-tube racks. It replaces acetal, which emitted formaldehyde fumes during high-heat sterilization. Nalge says Carilon passed requirements for dimensional stability, colorability, impact toughness, and resistance to autoclaving, and showed sufficient stiffness to overcome potential knit-line problems. Unlike the acetal it replaced, polyketone was receptive to lower-cost general-purpose colorants, and it molded in faster cycles.

High tolerance for fuels

Polyketone's fuel resistance is enabling it to challenge acetal and nylons 11 and 12 in a number of current and developing automotive applications. For example, Carilon has replaced nylon as the extruded inner liner for multilayer hose used in an underground fuel-delivery system. Replacing the nylon liner with Carilon corrugated tubing reduced permeation by corrosive oxygenated fuels to one-tenth the maximum allowable limit, according to Total Containment of Oaks, Pa. Cleveland Tubing of Cleveland, Tenn., extrudes the polyketone tube, which bonds to the hose's TPU outer layer.

Shell is also supplying Carilon to GT Products, Ann Arbor, Mich., for molding components of ORVR (on-board refueling vapor-recovery) valves, which are required by EPA for the first time on 1998 car models. Carilon replaced TP polyester because of its combination of strength and fuel resistance, says Ken Zander, GT Products sales manager.

Other automotive applications include extruded low-permeability fuel lines for Veritas in Germany and a BMW fuel reservoir that sits inside a fuel tank. BMW in Germany is also evaluating air-intake manifolds injection molded of Carilon by a lost-core process.

Numerous other auto parts are in development:

* Fuel tanks - Carilon, which can be directly exposed to gasoline, has the potential to eliminate the EVOH barrier layer and tie layer in coextrusion blow molded fuel tanks, reducing the number of layers from the present six to four, says Shell automotive end-use manager Paul Sykes. He expects such tanks to be available by early next year for trials in the U.S. In Europe, where new legislation may spell trouble for fluorinated-PE tanks, Shell is developing an injection molded monolayer fuel tank of Carilon. A prototype could be available for trials by the end of this year.

* Connectors - A transmission connector is being developed to withstand exposure to transmission fluid at high temperatures; it will replace nylon 46. A connector for the fuel tank is also being developed that will withstand immersion in E-85 fuel.

* Gears - In development are gears for actuator motors in a power-door assembly, whose components are now made of nylon and acetal.

* Under the hood - Potential uses of polyketones include fuel pumps, fuel rails, valve covers, and radiator tanks.