• New plastic for electrical and electronic applications
  • High mechanical strength and thermal stability

Cologne - Specialty chemicals company LANXESS has developed a new halogen-free flame-retardant polyamide 6 for electrical switches such as circuit breakers under the proprietary name Durethan BKV 25 FN27. Compared to the mineral-filled halogen-free polyamide 6 grades often used in the manufacture of circuit breakers for low-voltage applications, the glass-reinforced material impresses through its high mechanical strength and thermal stability. Components made from this effectively withstand the enormous mechanical stresses and high temperature peaks that occur during a short circuit. 'With this property profile our material also meets the requirements placed on a circuit breaker for higher performance classes (rated currents). This results in potential savings for the producers of these safety parts,' says Alexander Radeck, an expert in flame-retardant thermoplastics at LANXESS High Performance Materials business unit. The material already is demonstrating its advantages in circuit breakers manufactured by the Legrand group.

The savings result from the fact that Durethan BKV 25 FN27 can be used for circuit breakers of several performance classes. 'For the manufacture of various parts therefore only one material is required. Producers benefit from lower costs, for example for storage and logistic processes, but also in the quality control,' Radeck explains.

Excellent glow-wire resistance

Furthermore the chlorine- and bromine-free flame retardance package gives the polyamide good fire resistance, evidence of which is provided in tests according to the strict U.S. Underwriters Laboratories UL 94 V standard. The material is listed with the classification of V-2 for test pieces up to 0.75 millimeters thick. The result of the glow wire test on the finished component is particularly worthy of mention. In the test to IEC 60695-2-11, the material achieved the best possible GWFI (Glow Wire Flammability Index) value for plastics at 960 °C for specimen thicknesses of less than one millimeter. The high heat resistance is demonstrated in tests to ISO 75-1,-2. The HDT A value (Heat Distortion Temperature) is 155 °C.

High weld strength

A further benefit of the polyamide 6 is its lower density compared with mineral-filled equivalents, which also makes itself felt in the cost. It also shrinks isotropically and can be colored as required. Radeck: 'Its good weldability by ultrasound pays dividends in the processing steps that follow. High weld strengths can thereby be achieved.'

LANXESS is a leading specialty chemicals company with sales of EUR 8.0 billion in 2014 and about 16,300 employees in 29 countries. The company is currently represented at 52 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.

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