German special chemical company LANXESS has expanded the company’s flame-retardant thermoplastic products with the environmentally friendly product of halogen-free flame retardant PBT (polybutylene terephthalate), Pocan BFN glass fiber reinforced compound.
“They show better electrical properties, thermal stability and UV stability. Their mechanical properties are only slightly inferior to halogen-based flame retardants and pass through glass fibers,” said Alexander Radeck, LANXESS flame retardant PBT materials expert. Strengthen, they can reach the latter level. “
High flame retardant effect up to UL 94
The glass fiber content of this new compound is between 13% and 25%. As a follow-on development product of Pocan DP BFN 4230, they have achieved great success in the market and are used to manufacture connectors for electrical equipment and housings of AC tube drives, as well as various other applications. With innovative halogen-free flame retardant additives, they passed UL’s standard UL 94 flame test at the American Underwriters Laboratories Laboratories, and samples as thin as 0.4 mm were awarded the best grade V-0 certification. “Real-world testing has also confirmed the material’s extremely low metal contact corrosion,” Radeck said of another advantage of the material.
Excellent application opportunities in solar photovoltaic field
PBT made of halogen-based flame retardants has higher electrical tracking resistance, which allows CTI (Relative Tracking Index, UL746A) to achieve the best performance level grade PLC 0, while IPT (slope tracking, UL 746A ) Not less than 60 minutes at 1.5kV. “With higher tracking resistance, designers have greater freedom in designing components. Because they can arrange electrical components more compactly without worrying about short circuits and equipment failure caused by leakage,” Radeck said. The dielectric strength used to measure the high voltage resistance of insulating materials is also up to 30 kV / mm (ISO 60243-1) and is not affected by humidity levels. “In addition to being used in traditional electrical equipment, the electrical properties of the new PBT compound also make it have great application potential in the field of solar photovoltaics,” Radeck said.
Hardly yellowing under thermal stress
Another advantage of the new PBT is its resistance to thermal aging at high temperatures. According to UL 746B, it can reach a relative thermal index (RTI) of 150 ° C (0.4 mm). “After UV irradiation and thermal aging, the material’s better long-term heat resistance in the air can also achieve higher color stability, which is comparable to halogen-based flame retardant products,” Radeck said. “This material is therefore ideal for applications such as LED housing manufacturing.”
Stable manufacturing process, low density
The new PBT material is specially designed to ensure that it has a wider processing range and stable processing flow during injection molding. The shrinkage properties of the product are similar to those of PBT made of halogen compounds, so they can be processed in the same mold. “Product density can be reduced by up to 8%, thereby increasing the price-performance ratio of the product by reducing the use of materials,” Radeck said. A major element in identifying parts is the use of new materials that can be laser-marked for high contrast and precision marking.