DuPont Engineering Design Electronic Magazine
High-performance extrusion solutions
for wire and cable
By Ramòn Brugada and John B. Marshall
Wire and Cable Application Leaders at DuPont Engineering Polymers.
| Ramòn Brugada | John B. Marshall |
The wire and cable industry is currently facing several important challenges such as halogen-free flame retardancy, low smoke emissions, RoHS compliance, recyclability, phthalates-elimination and thin-wall structures for added space saving. Simultaneously, customers within the industry continue to seek new solutions that will maintain or improve on the properties of the thermoplastic or thermoset materials used today. These are the findings of research conducted by DuPont in the US, verified globally and taking into accounts standards such as UL (Underwriters Laboratories), SAE (Society of Automotive Engineers), and ISO (International Organization for Standardization). They have been used by DuPont as the basis for its ongoing development of a range of polymer-based material solutions for the wire and cable industry.
DuPont’s engineering thermoplastics offer customers the properties and benefits required to give their products that extra competitive edge: high-performance, lightweight cables and reduced processing costs for lower-cost final products and greater customer satisfaction. For example, wire insulation or jacketing made with DuPont polymers may require less material due to their thinner walls. As a consequence, the cables may become less expensive per length of wire, while delivering superior physical properties, such as improved flexibility at low temperatures, easier routing through tight spaces, improved flex fatigue performance, and good abrasion resistance. Moreover, specific DuPont polymers are plasticizer-, lead-, and halogen-free, making them RoHS compliant (the RoHS Directive stands for "the restriction of the use of certain hazardous substances in electrical and electronic equipment"). The thermoplastic products offered by DuPont Engineering Polymers are also reprocessable.
The range of materials provided by DuPont include a number of extrudable, speciality materials for the wire and cable industry, including DuPont™ Zytel® nylon resins, DuPont™ Crastin® PBT thermoplastic polyester resins, DuPont™ Hytrel® thermoplastic polyester elastomer resins and DuPont™ ETPV engineering thermoplastic vulcanizate. Further material-based solutions are provided by our colleagues in DuPont Flouropolymers, DuPont Packaging & Industrial Polymers and DuPont Performance Elastomers (see this page of this issue). End-use industries include automotive, transportation, robotics, appliance, shipyard, oil and alternative energies, to name a few. This broad product portfolio can be tailored to meet an ever-expanding range of application needs, and is based on the company’s global manufacturing and supply strength.
One principal function of the cover is the extraction of oil from the blow-by and the return of the blow-by-gases to the engine. To do this, the vacuum from the intake is used to suck the aerosol mixture, present in the crankcase, through the cyclone separator. A splash guard plate prevents the suction of splash oil from the camshaft. The larger oil droplets are obstructed by a perforated baffle and flow back to the crankcase. As a result, only the pre-purified blow-by mixture gets as far as the cyclone separator, where a rotating airstream is used to extract and collect the finest of oil-mist droplets, which are then drained away. The gas, which is now virtually free of oil, goes through the diaphragm valve, used to keep the vacuum in the crankcase within limits, to the engine air intake for reheating.
Companies such as Northwire in the US (see this issue) or LEONI elocab in Germany (see ED 2008-1) are leading the way in delivering the benefits of DuPont engineering polymers for insulation and jacketing applications, as well as for straight or coiled cables with enhanced elastic memory recovery over a wide temperature range. The excellent mechanical strength and dielectric strength of Hytrel®, for example, allows production of cables with extended flex life by providing effective insulation in thinner layers than many alternative materials (see "Bridging the divide"). Further key advantages of Hytrel® in cables that flex include a hard, abrasion-resistant surface, excellent flex fatigue resistance and chemical resistance – all over a wide temperature range. The material’s adoption for jacketing in the shipyard industry is attributable to its low smoke emission.
DuPont firmly believes, however, that today’s customers need more from their suppliers than just materials. They need a resource that is willing and able to assist the customer at the earliest stages of the product development process. One that can help a customer carry a project from concept through design, processing support, material selection, quality control, and even commercialization assistance. They need a fully engaged supply partner – and DuPont can be that partner. Should customers decide to work with DuPont from the initial design concept, and on through every stage to full production, DuPont can share its experience and knowledge to allow them to choose the optimum engineering polymer for their needs. The result? A very competitive, new and successful product.
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