Additives in PVC Wire & Cable
In PVC wire and cable formulations, beyond stabilizers, plasticizers, lubricants, and flame retardants, a range of complementary additives is employed to enhance durability, safety, and overall product performance. Antioxidants are among the most essential of these; combinations of primary phenolics such as AO-1010 with secondary phosphites like AO-168 form the most common stabilizing systems, protecting cables against oxidative degradation both during processing and throughout service life. For outdoor and UV-exposed applications, light stabilizers such as benzotriazoles and HALS are indispensable, significantly extending cable lifetime under harsh weather conditions
Smoke suppressants such as molybdates and zinc borates are also incorporated in fire-safe formulations to reduce smoke generation and promote the formation of protective char layers. Pigments and masterbatches play a crucial role in color coding and UV protection; carbon black, the most widely used pigment in black cables, not only provides color but also boosts UV resistance. Metallic stearates such as calcium and zinc stearate are often included as efficient lubricants that also synergize with stabilizers, ensuring smoother extrusion and process stability
In specific applications, biocides and fungicides are added to prevent microbial growth and surface degradation in buried or moisture-prone cables. To address plasticizer migration and blooming in long-life cables, high molecular weight polyesters or epoxy-based additives are used. Finally, advanced fillers such as nanoclays or silica are incorporated in engineered formulations to improve mechanical strength and dielectric properties
Flame Retardants in PVC Wire & Cable
Flame retardant additives are essential for ensuring the safety and compliance of PVC wires and cables. Antimony trioxide (Sb₂O₃) combined with the inherent chlorine in PVC and chlorinated paraffin (CP) as a secondary plasticizer forms the most common flame retardant system in standard cable formulations. For higher safety requirements, aluminum trihydroxide (ATH) and magnesium hydroxide (Mg(OH)₂) are widely used; both release water and form protective layers that reduce flame spread and smoke generation, with Mg(OH)₂ preferred in low-smoke, low-halogen (LSF/LSOH) cables due to its higher decomposition temperature. In advanced formulations, phosphorus–nitrogen (P–N) systems and smoke suppressants such as molybdates and zinc borates are added to maximize thermal stability and fire resistance