WCA November 2023

Technology News

Delta Tecnic designs masterbatches with the aim of reducing faults detected by the spark tester

Efficient insulation and accurate spark test results

and the resulting large unwanted particles can cause holes in the insulation. If properly mixed, the masterbatch is fully compounded and melted into the polymeric base. However, in some cases customers may face difficulties in diluting masterbatches, as the cable industry is increasingly working with faster and shorter extruders that make this process more complex. The challenge for the masterbatch manufacturer is to achieve the best dilution possible, which requires an appropriate temperature and mixing process. “At Delta Tecnic we strive to provide solutions that drive the advancement of the cable industry and improve the quality of cables used in various sectors,” said Manuel Miret, area manager and new product developer. “Our focus on the optimal dispersion of pigments and the formulation of our masterbatches to achieve a perfect dilution is essential to guarantee the excellence of manufactured cables and optimal results in the spark test during manufacturing.” Delta Tecnic https://deltatecnic.com

Holes may be caused by poor dispersion of the products used in the insulation mixture. Plastic insulation is made up of two materials: generally, 98 per cent is a polymeric compound either manufactured by the same cable manufacturer or supplied by companies specialised in compound manufacturing, while the remaining two per cent is the colourant provided. Both of these raw materials may contain particles that are poorly dispersed/incorporated into the polymeric mass, resulting in the formation of holes that will cause a failed spark test. A poorly manufactured masterbatch can be one of the causes of these holes, due to the presence of excessively large particles in the polymer. A masterbatch used in the cable industry should achieve the best possible pigment dispersion, which involves breaking the crystalline units that make up the pigments through a mechanical process using extruders, preventing them from remaining inside the masterbatch. Another possible fault relates to dilu- tion. During cable manufacturing, the masterbatch might not be properly diluted in the customer’s compound,

For the power cable industry, and especially in automotive cables, it is necessary to achieve total insulation of the electrical conductor (copper or aluminium, in most cases). The spark test aims to detect holes in the plastic layer covering the cable conductor. Even small holes can cause unwanted effects such as energy leaks and loss of electricity, creating serious problems in an electrical circuit. In the case of Delta Tecnic, 25 per cent of colour masterbatch sales are in the automotive industry – the sector that presents the most difficulty in obtaining satisfactory spark test results due to the use of shorter high-speed dilution machines. Industry requirements have led the company to design and control its masterbatches with the aim of reducing the faults detected by the spark tester. As the conductor cable, with its respective insulation, passes through the spark tester it is subjected to a high-voltage electric field to detect any leaks. If an electrical reaction occurs, the device emits a warning signal. It is crucial to avoid the presence of large unwanted particles in the cable insulation.

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November 2023