Economical alternative to high-melting specialty polyamides
LANXESS has developed Pocan TP 555-001, a new polyester material grade based on polyethylene terephthalate (PET), which is excellently suited to manufacturing housings, sockets and other components for light-emitting diodes (LED). What makes the product unique is its excellent light reflection, which hardly declines at all over time, and its high heat stability. “This high-tech material represents a new, growing material family that is our response to the global trend in LED light sources. It is designed as an economical alternative to specialty polyamides, materials frequently used to make components such as LED housings thanks to their high melting point,” explains Dr. Matthias Bienmüller, head of Pocan Product Development at LANXESS.
Next to no yellowing when exposed to light and heat
The new material grade is reinforced with glass fibers and contains special additives. Its light reflection is unusually high: over 90 percent at 450 nanometers. Used to make the housing, it therefore reflects the light of the LEDs almost completely, keeping brightness losses to a minimum. Another one of its strengths is its high resistance to aging by yellowing from exposure to light and heat. Even after 500 hours of aging at 140 °C, the light reflection still reaches values in the region of 90 percent. “Virtually no yellowing occurs under the normal operating conditions of an LED. In contrast, the light reflection of high-melting polyamides declines noticeably under these conditions, because they yellow,” says Dr. Timo Immel, LED applications specialist in Pocan Product Development.
Suitable for vapor phase soldering
Pocan TP 555-001 displays outstanding heat stability for a polyester in its material class. With its high melting point of roughly 260 °C, the material can withstand the temperatures prevailing during vapor phase soldering with lead-free solder. This is one of the methods used in LED manufacturing to solder electronic components.
Advantages also result when processing the new material. The high flowability of its melt makes it possible to produce thin-walled, intricately designed components. Compared to high-melting specialty polyamides, it can be injection molded at 50 to 60 °C lower temperatures. “This lowers the processor's energy consumption, which adds to the high cost efficiency of our innovative material,” Immel says.
LED growth market
LEDs are the light source of the future. Their energy consumption is significantly lower than that of incandescent and discharge lamps, and their service life longer. Growing potential for their use exists, for instance, in electronic display backlighting, building lighting and streetlamps. They likewise will continue to become established in automotive lighting. “Our high-tech polyamides and polyesters have major opportunities in LED lighting technology thanks to their set of properties. For example, we are at a very advanced stage in developing a polyester-based material grade that can withstand the even higher temperatures of reflow soldering than vapor phase soldering, and still displays outstanding LED light reflection,” Bienmüller says.
LANXESS (lanxess.com) is a leading specialty chemicals company with sales of EUR 9.1 billion in 2012 and roughly 17,400 employees in 31 countries. The company is currently represented at 50 production sites worldwide. The core business of LANXESS is the development, manufacturing and marketing of plastics, rubber, intermediates and specialty chemicals. LANXESS is a member of the leading sustainability indices Dow Jones Sustainability Index (DJSI) World and FTSE4Good as well as the Carbon Disclosure Leadership Index (CDLI).