Reprocessed nylon air-cleaner housings are voted most innovative at SPE Automotive Awards

Plastics Engineering, Dec, 1997 by Mark W. Shortt

A Ford Motor Co. program that converts nylon from post-consumer carpets into engine air-cleaner housings won two major awards at the 27th Annual SPE Automotive Awards, held November 12 in Detroit. The Carpet to Car Parts program, which reprocesses 27 million [ft.sup.2] of carpeting that would otherwise be destined for landfills each year, won the Grand Award as the most innovative overall application of automotive plastics. It also took top honors in the Environmental category Ford uses the air-cleaner housings in the engines of its North American-built cars and trucks.

The automotive awards are sponsored by the SPE Automotive Division and Detroit Section. They recognize the most innovative use of plastics in the automotive categories of Environmental, Materials, Powertrain, Body Exterior, Body Interior, Process, and Chassis. A Hall of Fame Award is also given annually for an automotive plastics application that has been in continuous use for 10 or more years.

The Carpet to Car Parts project is a joint undertaking of Ford and DuPont Automotive, which performs all the reprocessing at its plant in Chattanooga, Tennessee. DuPont uses a proprietary technology that melts and mixes post-consumer nylon carpet fibers with virgin nylon. The result is DuPont Minlon PCR FE6202, a mineral-reinforced nylon that Ford Visteon uses to manufacture the air-cleaner housings at its plant in Sandusky, Ohio. The material is reported to meet automaker specifications for components of air induction systems.

All the air-cleaner housings have 25% post-consumer recycled content by weight. They are products of what is said to be the world's largest program for using recycled engineering plastics in automobiles. Their combination of favorable performance, environmental impact, and manufacturing cost parity with equivalent products distinguished them as the top overall application.

Top Material Is an Electrically Dissipative TPO

The first conductively modified TPO (thermoplastic olefin) resin for electrostatically painted parts won top honors in the Materials category Ford Visteon used the Dexflex TPO resin for the electrostatically painted front fascia of the 1997 Ford DN101 Sable, and is also using it for the 1998 model year. According to Ford researchers, the application shows that low levels of conducting carbon fillers can be used to generate cost-effective, dissipating thermoplastic resins without sacrificing mechanical properties. Solvay Engineered Polymers supplies the resin, which is said to significantly reduce paint costs by eliminating need for an adhesion promoter and primer. The resin is also reported to permit more uniform paint coverage and increase first-run capability and resistance to paint surface damage. It has a carbon filler content of 10%, low enough to permit paint transfer efficiencies equivalent to those of steel.

According to Ford, the researchers achieved conductive modification of the resin by incorporating high-structure, conducting carbon blacks at cost-effective levels below 5 wt%. They achieved electrostatic painting performance equivalent to that of steel by ensuring that the internal electrical resistance value remained below [10.sup.9] ohm/cm. Injection molded samples were reported to exhibit a variation in surface-to-core resistivity, associated with the dependence of carbon aggregate structure on thermal quenching at the mold wall and shear history The application is said to refute the paradigm that attributes electrostatic paintability to surface or volume resistivity.

First Air-Filter Housing Produced by Gas-Assist Technology Wins in Powertrain

A thermoplastic flat air-filter housing, an alternative to round metal filter housings and the first of its kind for heavy-duty trucks, was voted the most innovative use of plastics in a powertrain application. Filterwerk Mann and Hummel (Germany) manufactured the filter housing for use on the 1997 Mercedes Benz Actros 500 Series heavy-duty trucks. The frame design answers the packaging constraints of cramped engine compartments by incorporating a large (15 [cm.sup.2]) filter surface area in a flat housing, Measuring 500 x 700 x 350 mm, the filter housing is one of the largest components in the world to be molded of glass-reinforced nylon 66. Zytel 35% glass-reinforced PA 66, supplied by DuPont Engineering Polymers, replaces the metal used in traditional round filter housings.

The challenges of molding such a large part were met with gas-assist injection technology, which improved flow into the mold and helped obtain needed part stiffness and dimensional stability. Gas-assist injection also provides an optimal sealing surface by maintaining flatness and dimensional stability at the seal.

The filter housing is said to extend filter service intervals to 10,000 km (more than 6000 miles). Its integral ribbing and housing contours reduce noise and vibration and counteract engine pulsation by holding the filter in place during operation. To save space under the hood, the filter housing can be mounted horizontally in the engine compartment or vertically behind the driver's cab. At 15.5 lbs (7 kg), the filter housing reduces weight by 50% and cost by 20% to 30% over a similar metal component.