Envalior has developed a new halogen-free, flame-retardant polybutylene terephthalate, marketed as Pocan BFN4232ZHR S1, for demanding high-voltage plastic components. The compound combines typical PBT strengths, including high dimensional stability, low propensity for electro corrosion and reliable electrical insulation at elevated temperatures, with property levels comparable to polyamide 6 and 66 in terms of hydrolysis resistance, creep resistance and elongation at break. According to the company, the grade is being evaluated for applications that have traditionally relied on polyamide, notably connectors in ultrafast charging infrastructure for electric vehicles with charging voltages of 800 V and above, 800 V power supply systems for AI data centers and secondary 48 V board supply in hybrid vehicles. Additional potential uses include housings and electrical components in smart grid devices. Envalior plans to expand the offering with variants featuring different glass fiber contents optimized for specific property profiles. The material can be laser-marked in all colors, including data matrix codes, and is also available with renewable raw materials via bio-based butanediol.
"We see great application potential above all in connectors used in ultrafast-charging stations for electric cars with charging voltages of 800 volts and above, in 800-volt power supply systems for AI data centers, and also in secondary 48-volt board supply, for example for hybrid vehicles. Other potential applications include housings and electrical components in the rapidly growing market for smart grid devices," said Dr. Jochen Endtner, Head of Product Development for Pocan at Envalior.
High-voltage connectors are a potential application for the new Pocan PBT. It offers greater design freedom and reliable performance, even under extreme conditions
Mechanical and electrical performance
A key characteristic of the new grade is its elongation at break of over 2.5 percent according to ISO 527-1,-2, which is comparable to flame-retardant polyamide compounds. Components can absorb more energy under load, helping to reduce brittle failure and stress cracking, which broadens design freedom and application scope. The elongation at break is maintained even after numerous extreme temperature cycles due to the material’s high resistance to hydrolysis and heat aging.
In specimen testing, the compound shows strong hydrolysis resistance. Mechanical properties such as elongation at break remain well above 70 percent after 1,000 hours at 85°C and 85 percent relative humidity. In long-term testing based on SAE/USCAR 2 Rev.7, the material achieves USCAR Class 3. Tracking resistance reaches the maximum rating of 600 in the CTI A test per IEC 60112, fulfilling the highest insulation class under IEC 60664-1. This CTI performance is retained in orange and black colorations, which Envalior highlights as unique for a PBT compound reinforced with 25 percent glass fibers.
Fire performance in the UL 94 test by Underwriters Laboratories Inc. is rated V-0 at 0.75 mm in all colors, which supports color coding of connectors in wiring harnesses. "The compound's high flame resistance and tracking resistance make it easier for designers to create very thin-walled and compact components without compromising electrical safety. This results in low material consumption and ideal use of the installation space," added Endtner. Long-term heat aging in air was also examined. The material’s tensile strength remains at a high level after 3,000 hours of hot air storage at 150°C.
Property profile of Pocan BFN4232ZHR S1. The PBT shows excellent mechanical stability, processing, and hydrolysis resistance, making it a strong alternative to traditional polyamides (e@b = elongation at break)
Processing and regulatory aspects
Pocan BFN4232ZHR S1 is formulated without halogenated ingredients and contains no polyfluorinated alkyl substances. During injection molding, the additive package does not release decomposition products known to be harmful to occupational health, such as isocyanates or phosphine. "We are thus offering a design material that does not require a high level of occupational safety measures and meets all current and expected regulatory requirements in the near future. Our customers can therefore rely on being able to use the compound safely and long-term," said Endtner.
Broader portfolio and trade show presence
Envalior’s portfolio for high-voltage connectors includes halogen-free flame-retardant compounds from multiple material classes that combine CTI 600, UL 94 V-0 and robust mechanical performance. These include dimensionally stable, mechanically and thermally resilient polyphthalamide compounds under the ForTii brand and various polyamide 66 grades under the Akulon brand. Selected PA 66 materials are designed to minimize corrosion of silicone seals in connectors, supporting durable sealing performance.
The new PBT will be showcased at K 2025, Hall 6, Stand B11, October 8 to 15, 2025, Messe Düsseldorf, Germany, and at The Battery Show North America 2025, Booth 408, October 6 to 9, 2025, Detroit, MI, U.S.
