PCT challenges polyamides in LED lighting
A new option is available to designers of LED lighting systems for vehicles with the introduction of a series of polycyclohexylene-dimethylene terephthalates (PCT) compounds that reportedly deliver outstanding initial reflectance and reflectance stability, which are attributes required in light-emitting diode (LED) packages found in display backlight and general lighting.
Developed and marketed by Ticona (Sulzbach, Germany), “These super-white Thermx PCT LED grades provide customers with much better color and reflectance stability than commonly used PA9T and PA6T nylons at high temperature,” according to Ruth Castillo, Thermx PCT and Vectra LCP global business director – Ticona.
Thermx LED 0201 and Thermx LED 0201S are fiber-filled, super-white PCT compounds. They reportedly withstand the demanding LED requirements for reflector resins with regard to heat and light stability —high initial reflectance; high reflectance stability under heat and light; excellent silicone adhesion; excellent processability; excellent mechanical strength and flexibility versus high temperature polyamides; surface mount technology reflow capability; and low moisture absorption. “This LED product family meets the optical and mechanical properties as well as the process requirements for specific applications,” continues Castillo.
“In addition to possessing the desirable chemical resistance, processability, and dimensional stability of engineering polyesters, such as polyethylene terephthalates (PET) and polybutylene terephthalates (PBT), Thermx PCT provides added heat resistance, making it particularly well suited for demanding automotive and electrical/electronics applications,” adds Castillo.
The polyester materials are lead-free solderable, with short-term heat resistance up to 260ºC (500ºF). High CTI and arc resistance, high dielectric strength, and low dielectric constant are also claimed, while shrinkage is the same as PBT. Chemical resistance to automotive fluids is also a bonus for automakers, while excellent surface appearance and colorability also come into the equation.