The world of wires and cables is diverse, offering various cable designs. While there are limitations for foaming in high voltage power land and submarine cables due to the high electrical stresses, the many low voltage cables and data cable types show great potential to reduce material consumption in the range of 15% to 25% for jacketing and insulation, and even 30% to 60% for bedding and filling compounds. This goes hand in hand with increased cable flexibility, weight reduction and an improved carbon footprint.
A further trend towards replacing the environmentally critical Azo compounds used in chemical foaming of coaxial cables by physical foaming technology results in lower long-term costs, higher process and product stability and end-of-life recyclability.
Cables require a super-smooth surface of their sheathing. If required, by applying a very thin skin layer extruded over the foamed jacket, cable manufacturers have additional design options to benefit from the material savings.
All relevant polymeric materials, by means of LDPE, HDPE, PBT, EVA, Polyolefin elastomers, including filled systems, and PVC have been used in combination with the Microcell Foaming Technology. Performance benefits on the electrical side, i.e. improved dielectric constant and reduced external electrical interference, were realized.
On the mechanical side, higher cable flexibility and a very stable foaming process resulting in narrow diameter tolerances are the outcome for the performance characteristics. The high-quality cell structure made with Microcell Foaming Technology permits a wide application range for wires & cables.
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| Photos: Promix Soilutions |
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The picture (left) showcases an example of a sensor data cable as used in automotive, where the bedding is foamed. The picture on the right of an A-B jacket with a thin skin-layer highlights the potential for jacketing applications in data and power cables.
Gas dosing stations for physical foaming function either on a mass-flow or pressure-controlled dosing regulation. Promix offers both types of systems, matching customer needs by applications.
Besides the actual cable, microducts (material savings of 10%-15%, mono and multi-layer) and cable protection tubes (material savings of 10%-25%, multi-layer) serving as cable infrastructure are more examples enabling physical foaming to save material cost and improve their sustainability footprint.
Promix Microcell Technology works for all types of extrusion processes including cables, packaging, films, sheets and boards, pipes and profiles, blown film and extrusion blow molding as well as thermoforming. The technology can be retrofited to existing extrusion lines as well as installed in new lines. Promix is working with a number of machine builders to achieve a perfect match.
