Exploration of Extrusion Process of Sheath Materials with Class B₁ Flame Retardant

With the acceleration of urbanization and the increasing requirements for safety and environmental protection, material of cable sheaths has gradually shifted from polyvinyl chloride (PVC) to highly flame-retardant materials. To meet Class B₁ (d₀, t₀, a₁) flame retardant standards, focusing on the application of low-smoke halogen-free flame-retardant materials in the extrusion process of cable sheaths, material that could meet Class B₁ flame retardant was identified by comparing the performance of three types of experimental sheath materials. In terms of extrusion process improvement, key factors such as the distributor, distributor cone, extrusion temperature, die selection, and screw selection were optimized, and cable structure was modified by adding flame-retardant tape layers inside and outside the armor layer. After repeated experiments, one of the sheath material was found to fully comply with the combustion requirements of sheath material with Class B₁ flame retardant and could meet environmental standards. Although the extrusion process of materials with Class B₁ flame retardant is challenging, their superior flame-retardant properties make them promising for rapid urban development, offering significant economic and social benefits to both enterprises and society.