DuPont today unveiled a new class of nylons that are
positioned between standard nylons and many typical high-performance
thermoplastics such as polyphthalamide (PPA) and polyphenylene sulfide (PPS).
"Performance demands in automotive continue to increase," says Patrick Ferronato, global marketing director for DuPont Automotive Performance Polymers. "Zytel(R) PLUS nylon meets these demands with better durability while maintaining the design and processing ease familiar with nylon to invite even more opportunities to replace metal for cost and weight savings."
Tests show the new nylons display improved property retention when exposed 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 of thermoplastic components exposed to hot, chemically aggressive and humid environments," says Rob Palmer, research and development senior research associate at DuPont Performance Polymers.
DuPont declined to provide specific pricing data, but ZytelPlus apparently 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 quantities based on industry estimates. Exact price points undoubtedly will depend on how aggressively DuPont wants to pursue specific applications that have long been the domain of metals or high-cost polymers.
Some examples of under-the-hood targets were provided by Gianluigi Molteni, global powertrain lead for DuPont Automotive Performance Polymers in an interview with Design News yesterday:
- radiator end caps,
- engine covers,
- oil pans,
- resonators and
- turbo charger end caps.
Molteni says engineers will benefit most from developing new designs using ZytelPlus rather than using it as a drop-in replacement for existing materials. Typical automotive design cycles are two to three years, and DuPont will be targeting advanced development teams set up by automotive OEMs.
In some cases, however, ZytelPlus could improve the economics of existing nylon under-the-hood applications. For example, the thickness of intake manifold walls could be reduced with the new material.
New engines will require higher performing materials because of a reduction in the amount of air passing through the engine compartment. That's due to the increasingly limited available space and the encasing of engines and the end-to-end cladding of the undercarriage. DuPont says temperatures under-the-hood are rising from 150 to 180C and more, with peaks of 230C possible in some cases.
DuPont says Zytel(R) PLUS 95G35 nylon, one of four new grades, provides exceptionally good long-term performance at temperatures up to 210C or even 230C for shorter periods. Grade 95G50 adds better stiffness and creep properties at high temperatures.
Zytel(R) PLUS 93G35 nylon provides good long-term performance despite exposure to heat plus improved weld lines and good performance in burst tests. Zytel(R) PLUS 90G30 provides exceptional resistance to hot engine coolant plus excellent properties 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 later date. Interestingly, the new materials feature a superior surface appearance to standard nylons, possibly opening up applications in electronics or other non-automotive applications.
The new plastic is based on a new, proprietary technology from DuPont called "SHIELD." It includes a new polymer backbone, polymer modifications and special additives. "We are investigating other polymers whose performance also could be greatly enhanced with DuPontTM SHIELD technologies," says Bob Lawton, global technology manager for Zytel(R).