New polyphthalamide (PPA) grades offer greater corrosion resistance for molded parts that are in intimate contact with delicate metal components, particularly fine copper magnet wire or sensitive electrical contacts that must operate in the hot, humid, or wet environments sometimes found in automotive and industrial applications. The electrical/electronics friendly (EF) grades of DuPont Zytel HTN PPA resins have enhanced retention of volume resistivity following moisture exposure compared to standard Zytel HTN grades. Tested in DuPont Technical Centers, the company reports that the EF grades passed CTI test under the most severe conditions.
In a car, the material could see use in high-voltage cable connectors for electric and hybrid vehicles, as well as encapsulated sensors for monitoring wheel speed; air or hydraulic pressure; and transmission functions. More broadly, the material would offer benefits for any electrical components where retention of electrical properties with moisture exposure is needed.
Like their Zytel HTN cousins, the new EF grades are based on aromatic copolymers, giving them excellent retention of strength and stiffness at elevated temperatures. They also feature a relatively low coefficient of thermal expansion, which contributes to their overall performance, especially with regard to form/fit, in encapsulated parts such as sensors.
The resin family will launch with three new grades, offering variations in property retention, flow, and impact resistance. Zytel HTN51G35EF will offer the highest retention of properties under long-term exposure to moisture, chemicals, and elevated temperatures. Zytel HTN52G35EF has enhanced flow and targets parts with thin-wall sections, such as connectors. Zytel HTN54G35EF provides improved impact resistance, with DuPont reporting that it excels in thermal cycling performance—a key factor in encapsulation applications. Both HTN52G35EF and HTN54G35EF also allow processors to use water for mold-temperature control. All three resins contain 35% glass-fiber reinforcement. —[email protected]