New DuPont Nylons Boost Under-the-Hood Performance

DuPont today unveiled a new class of nylons that arepositioned between standard nylons and many typical high-performancethermoplastics such as polyphthalamide (PPA) and polyphenylene sulfide (PPS).

"Performance demands in automotive continue to increase," says PatrickFerronato, global marketing director for DuPont Automotive PerformancePolymers. "Zytel(R) PLUS nylon meets thesedemands with better durability while maintaining the design and processing easefamiliar with nylon to invite even more opportunities to replace metal for costand weight savings."

Tests show the new nylons display improved property retention whenexposed to calcium chloride or to 3,000 or 4,000 hours of hot air, hot oil,water and long-life coolant.

"In many cases, Zytel(R) PLUS nylon will be able to double the life ofthermoplastic components exposed to hot, chemically aggressive and humidenvironments," says Rob Palmer, research and development senior researchassociate at DuPont Performance Polymers.

DuPont declined to provide specific pricing data, but ZytelPlusapparently will fall between standard nylon 6/6 ($1.75/lb) and PPS ($4.50/lb).Prices are ballpark estimates for standard grades in medium-volume quantitiesbased on industry estimates. Exact price points undoubtedly will depend on howaggressively DuPont wants to pursue specific applications that have long beenthe domain of metals or high-cost polymers.

Some examples of under-the-hood targets were provided by GianluigiMolteni, global powertrain lead for DuPont Automotive Performance Polymers inan interview with Design News yesterday:

Molteni says engineers will benefit most from developing newdesigns using ZytelPlus rather than using it as a drop-in replacement for existingmaterials. Typical automotive design cycles are two to three years, and DuPontwill be targeting advanced development teams set up by automotive OEMs.

In some cases, however, ZytelPlus could improve the economics ofexisting nylon under-the-hood applications. For example, the thickness ofintake manifold walls could be reduced with the new material.

New engines will require higher performing materials because of areduction in the amount of air passing through the engine compartment. That'sdue to the increasingly limited available space and the encasing of engines andthe end-to-end cladding of the undercarriage. DuPont says temperaturesunder-the-hood are rising from 150 to 180C and more, with peaks of 230Cpossible in some cases.

DuPont says Zytel(R) PLUS 95G35 nylon, one of four new grades, provides exceptionallygood long-term performance at temperatures up to 210C or even 230C for shorterperiods. Grade 95G50 adds better stiffness and creep properties at hightemperatures.

Zytel(R) PLUS 93G35 nylon provides good long-term performance despiteexposure to heat plus improved weld lines and good performance in burst tests. Zytel(R)PLUS 90G30 provides exceptional resistance to hot engine coolant plus excellentproperties in contact with water.

Levels of glass reinforcement range from 30 to 50 percent. Molteni says DuPont may introduce unreinforced and flame-retarded grades at a laterdate. Interestingly, the new materialsfeature a superior surface appearance to standard nylons, possibly opening upapplications in electronics or other non-automotive applications.

The new plastic is based on a new, proprietary technology from DuPontcalled "SHIELD." It includes a new polymer backbone, polymer modificationsand special additives. "We are investigating other polymers whose performancealso could be greatly enhanced with DuPont^TM SHIELD technologies," says BobLawton, global technology manager for Zytel(R).

New DuPont Nylons Boost Under-the-Hood Performance A