DuPont: New Teflon® fluoropolymers with improved processability for high performance cabling

DuPont is demonstrating the company’s comprehensive portfolio of materials for the cable and wire industry during
Wire 2006 in Düsseldorf, Germany, 24-28 April 2006 (Stand G58, Hall 11). Part of the DuPont Advanced Fibres’ display at the show will include Kevlar® brand fibre for the protection of communication and data transmission cables. Meanwhile, DuPont Performance Coatings will provide an overview of its range of wire enamels and isolating coatings. Finally, DuPont Fluoropolymer Solutions is using Wire 2006 to introduce new developments in fluoropolymer technology for the manufacture of electrical insulation for cables and wires. These include Teflon® FEP CJ 99, which combines high levels of stress cracking resistance with speed of processing,
and Teflon® 640 XT, which has been modified to enable the particularly efficient manufacture of high-performance cables. Teflon® FEP CJ 99 is an all-purpose melt-processable copolymer grade of tetrafluoroethylene and hexafluoropropylene. Its high melt flow rate (MFR = 9 g/10 min) enables high productivity during the manufacture of wire and cable insulation. Comparative analysis of thin films of resin, using standard ASTM D 2176 to measure the MIT Flex Life , show high performance in terms of stress cracking resistance of Teflon® FEP CJ 99. Those FEP grades with similar levels of stress crack resistance have a lower melt flow rate and are thus lower in productivity. The advantageous combination of high stress crack resistance and high productivity means that this particular grade is
highly suitable for cables requiring compliance with specific winding tests at temperatures between 220 and 230 °C. Further applications include the primary insulation of large diameter automotive cables, electrical floor heating cables and the jacket insulation of LAN and coaxial cables.

Teflon® 640 XT, a PTFE fine powder resin for paste extrusion, enables a broad range of reduction ratios during cable manufacture, ranging from 250:1 up to 5000:1. Even at both extremes, a lubricant content of only 16 percent of the overall weight is needed, with the consequence that just one single PTFE-lubricant mixture can permit a multitude of reduction ratios. The required extrusion pressure is very low. Teflon® 640 XT facilitates the manufacture of particularly high-quality, thin-walled insulation with low
diameter fluctuations and virtually no surface defects. The low lubricant content allows for increased extrusion speed and lower lubricant usage. Typical applications include wires and cables for automotive engine compartments, antennas or medical equipment.

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