lanxess EE
At LANXESS, a halogen-free flame-retardant PBT compound is currently under development that shows outstanding results in glow-wire testing to IEC 60695-2-10. Photo: LANXESS AG
LANXESS is expanding its portfolio of halogen-free, flame-retardant compounds based on polybutylene terephthalate (PBT) and polyamide (PA 6, PA 66).
The company says in terms of properties and processing, the new materials are “on par with, or even superior to”, their counterparts containing halogen-based flame retardance packages.
“We believe that sales of these products will benefit in the future from global trends, such as Industry 4.0, electromobility and digitally networked building systems, household devices and consumer electronics,” explained Alexander Radeck, Applications Developer in the Lanxess High Performance Materials (HPM) business unit.
New additions to the Pocan BFN PBT product line, which previously encompassed materials with 13, 25 and 30 percent glass fibre reinforcement, include Pocan BFN2502, BFN4221 and BFN6410. Pocan BFN2502 is a non-reinforced material that displays a high elongation at break of over seven percent despite its halogen-free flame retardance package. It passes the UL 94 standard fire tests, achieving the best classification of V-0 (0.4 millimeters).
Next, new Pocan BFN4221 has a glass fibre content of 20 percent. Like its ‘sister products’, this compound is said to display not only high flame retardance attributable to a low tendency toward corrosion in contact with metals, but also good thermal aging resistance and colour stability at elevated temperatures, a wide processing window and good suitability for high-contrast laser marking.
Thirdly, Pocan BFN6410 targets applications in lighting and LED technology. “Its light reflection of more than 94 percent at 450 nanometers is unusually high, meaning that when used as a housing material, it reflects LED light almost entirely,” said Radeck. It also offers high blue light resistance and high lightproofness even at thin wall thicknesses. The material further displays good mechanical behaviour and a low tendency to warp. It achieves the best classification in UL 94 fire testing of V-0 (0.75 millimeters).
Furthermore, Lanxess says a PBT compound is currently under development that shows “outstanding results” in glow-wire testing to IEC 60695-2-10. These tests assess the ignition properties and afterburn behavior of plastics that come into contact with overheated or incandescent metal parts.
“Our material proves that not only halogen-based, but also halogen-free flame retardance packages can support good glow-wire resistance levels in PBT compounds,” added Radeck. The new material also achieves very good results in the glow-wire testing of end products (GWEPT, Glow-Wire Flammability Test Method for End Products, IEC 60695-2-11).
“This test is very demanding because end products, which can have complex geometries and metal inserts, frequently display less favourable behavior than simple test specimens,” Radeck continued. The new material under development also has the potential to pass the stricter glow-wire tests required under IEC 60335-1 for unattended household appliances (“no flame”).
A new product among the halogen-free flame-retardant polyamide 66 grades is Durethan AKV30FN04LT. This is optimised for laser transmission welding, a process increasingly used for joining electrical and electronic assemblies because it is associated with only limited thermal loading and is dust-free. The compound contains the XTS3 heat stabilisation system and therefore can be used at higher continuous service temperatures. It passes UL 94 standard fire testing with the best classification of V-0 (0.4 millimeters) and achieves high tracking resistance of 600 volts in tests to IEC 60112. One of its potential applications is safety switches.