Mar 31 2004
DuPont is expanding its materials and technology offering for automotive fuel systems with new DuPont™ Zytel® CDV conductive nylons and with a new DuPont™ Delrin® acetal resin that stands up in hot diesel fuel. The new materials are making their debut at the SAE World Congress here this week.
"Armed with new DuPont conductive materials, know-how and experience in fuel systems, we can give design engineers powerful tools for meeting both functional and static dissipation requirements," said Brian Fish, marketing manager for DuPont™ Zytel® CDV. "Here at DuPont, we draw on a variety of nylon base polymers, modification technologies, reinforcements, fillers and other ingredients to meet customer needs."
DuPont™ Zytel® CDV nylons can make a wide variety of static-dissipating functional parts for automotive fuel systems and other uses. Potential fuel applications include the tank cap, filler neck components, check valve, filter housing, tube bundle clips, fuel line connectors and the fuel rail. Other automotive applications include parts for electrical and electronically controlled devices subject to static buildup – power steering, for example.
Powder-coated parts for automotive and other industrial products are another potential application for Zytel® CDV. In this case, the inherently conductive resin can save the substantial cost of applying a conductive primer to molded parts.
Zytel® CDV can also play a valuable role in the dissipation of static charges in business machines, computer peripherals, electronic devices, industrial machinery, medical equipment and other products.
The initial Zytel® CDV offering consists of four grades using PA66 in both standard and modified form or PA612 as base polymers. Parts made from these grades can meet resistivity recommendations (106 ohm cm, maximum) of the latest SAE J1645 standard. Additional resins are in advanced stages of evaluation and development, including high performance polyamide materials, according to Fish.
New Delrin® 560HD has what it takes to withstand diesel fuel at the 90°C-or-higher temperature of pressurized fuel burned in the emerging generation of low-emission diesel engines.
"Acetal polymers like Delrin® have become the preferred material for many conventional fuel system applications," said Mike Day, development programs manager at DuPont Engineering Polymers. "Now with new hot-diesel-resistant Delrin®, fuel system suppliers and OEM's have the ability to continue the use of acetal polymer even for feeding hot diesel fuel as seen in engines using direct unit injection and common rail technology. Delrin® 560HD is an economical but sufficiently durable alternative to metal and higher-priced polymers for components of such systems," he added. Potential applications include fuel pump reservoirs, connectors, the tank flange and related parts, according to Day.
In tests conducted with a very aggressive diesel fuel at 100°C, test specimens made of the new resin outperformed both a standard acetal and several other acetal resins promising improved hot diesel resistance. After 336 hours, for example, Delrin® 560HD retained 98 percent of its original mass while only 20 percent of a standard acetal specimen remained.
For more information on polyamide 66, click here.