Utkarsh Thakre, Manager, OEM Marketing and Technical Services, Evonik

Evonik Industries is a technology leader with almost 60 years of experience in creating high performance polymers, foams and membranes that elevate products. The company’s innovative materials and processes provide solutions for better cost efficiency, environment-fri­endly systems, and increased resistance to chemical and mechanical strains. With cus­tomised high performance materials, Evonik improves the quality of life for today and tomorrow.

One of the industries that Evonik serv­es is the cable and wire industry. The company manufactures a range of polyamide, po­lybutylene terephthalate and polyether ether ketone (PEEK) extrusion grades for cable and wire coatings, jacketing, fibre op­ti­cal jacketing, loose tubes, as well as ca­ble protection tubing and profiles. The­se ma­terials have been protecting cables, as ei­ther sheathing or protection tubing, for ma­ny years. Further, continuous im­pro­ve­m­ents have made these materials the first ch­oice for the electronics and cable industry.

Evonik’s VESTAMID® L polyamide 12 (PA 12) is ideal for cable and wire coatings/jacketing, and cable protection tubes. It has low water absorption, very high chemical resistance, high hydrolysis resistance, excellent cold impact performance, high hardness and abrasion resistance, high dynamic load behaviour, and excellent properties in flame retardancy. The VESTAMID® E polyamide 12 elastomer is perfect for highly flexible cable coatings and jacketing. The VESTODUR® polybutylene terephthalate is suitable for fibre optical jacketing and loose tubes. The VESTAKEEP® PEEK polyether ether ketone is ideal for cable and wire coatings in high-end applications.

Fibre optic cables are designed to meet various operational specifications for different applications. Among the many existing designs, each has its own ideal application. Tight and semi-tight jacketing is mainly used for indoor cables, patch cord cables and connector pigtails. In this case, an optical fibre in the core is protected by a multilayer cable construction. The loose tube design is another common cable design in the market. In the loose tube design, each fibre or multi-fibre bundle is held loosely inside a polymer tube. The tube is typically filled with a moisture repellent jelly compound. The jelly-filled tube gives the fibres excellent protection against various external forces acting on the cable. None of these forces are transferred directly to the fibres. In addition, the tubes are stranded around the central strength member (helically or through the SZ method). This design creates a strain relief effect and this is the most important advantage of the loose tube design. The cable core is protected by various wrappings, polymer jackets and additional reinforcements in the form of strength member layers or armoring.

Evonik’s VESTAMID® L1940 and VESTAMID® L2140 are recommended grades for providing mechanical protection to loose fibre bundle cables. VESTODUR® 3013 and VESTODUR® X7396 are also suitable for this application. These materials have high line speeds of up to 400 metres per minute, high stability during extrusion with less scrap, fast crystallisation for better fibre excess length control, high chemical resistance (filling compound, inhibits H2O penetration), and high hydrolysis resistance in compliance with the Belcore test under 85 °C and 85 per cent relative humidity.

Telecom operators in certain countries in the southern hemisphere, such as Austra­lia, Brazil and India, have specified PA 12 compounds as a protective jacketing for underground cables. In addition to its particularly high weathering resistance, rigid VESTAMID® compounds have a high deg­ree of ant and termite resistance. The out­standing toughness also protects telecommunication cables against attacks by rode­nts. While standard polyethylene (PE) jacketing is destroyed by rats in a short time, rodents stop gnawing cables protected with polyamide 12 grades VESTAMID® L1940, L2140, or L2170, because they fail to make any progress. The same happens with ant and termite attacks. Not only do termites gnaw the cable sheathing, but they also secrete aggressive formic acid that can corrupt the cable sheathing. PA 12 has ex­cell­ent resistance to formic acid; it does not swell and prevents gnawing attacks.

In conclusion, the company’s materials are ideal for the cable and wire industry, and they have been protecting cables, in the form of sheathing or protection tubing, for many years.