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. "ZytelŪ 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, ZytelŪ 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,
turbo charger end
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 ZytelŪ 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
ZytelŪ PLUS 93G35 nylon provides good long-term performance despite
exposure to heat plus improved weld lines and good performance in burst tests. ZytelŪ
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 ZytelŪ.