DuPont: Impact resistant, low-emission POM in automotive interiors

With its reduced formaldehyde content and low rate of emission release, DuPont™ Delrin® 300TE acetal resin is the first impact-modified POM from DuPont to meet the automotive industry´s demanding requirements for the use of plastics in vehicle interiors. Its melt flow index (MFI190/2,16) of 6 g/10min bridges the gap between Delrin® 100T (MFI = 2), which combines high viscosity with very high impact resistance, and the medium viscosity, stiffer Delrin® 500T (MFI = 12). This extends the scope of application for Delrin® acetal resins in vehicles to include plastic components in interiors, where high resistance to impact loads is required.

"In the light of rising demands on quality amongst consumers, the automotive industry now sets extremely low limits for the emission of volatile organic compounds (VOC)," explains Hans-Hermann Kirner, material development manager for automotive interiors at DuPont. "Tests of samples of the new impact-modified Delrin® 300TE, conducted by the renowned independent Fresenius Institute in Herten, Germany, revealed formaldehyde emissions of 1.0 mg/m² and lower. Such results are considerably below the limit of 2.0 mg/m² set by leading German OEMs and mean that the new material meets the world´s most stringent requirements with regard to VOC emissions in this sector."

Delrin® 300TE is considerably more impact resistant than Delrin® 300PE, a previously launched low-emission grade that is also suitable for use in automotive interiors. It achieves a notched impact strength at 23 °C of 18 kJ/m² (Delrin® 300PE: 11 kJ/m²).

At -30 °C, the notched impact strength of the new 300TE grade is still as high as 10 kJ/m² (300PE: 8 kJ/m²). As with all members of the acetal resin family from DuPont, new Delrin® 300TE also combines high strength, hardness and stiffness over a broad temperature range with high abrasion resistance and a low coefficient of friction, a high heat deflection temperature, good electrical and dielectric properties and high dimensional stability.

Kirner adds: "Thanks to its high melt flow, thin-walled parts with long flow paths - for instance the struts used in headrests - are amongst the principal areas for developments in Delrin® 300TE. In general all POM grades are suitable for use in low-noise and low-friction control and drive systems. Similarly low-emission grades currently under development - Delrin® 100TE and Delrin® 500TE, which is suitable for particularly delicate, small parts - will provide further opportunities for new applications."