Modification of Low-Smoke Halogen-Free Flame Retardant Thermoplastic Polyurethane Elastomer Sheath Material

To investigate thermoplastic polyurethane elastomers (TPU) for low-smoke halogen-free flame retardant cables, TPU was prepared by using aluminium hydroxide (ATH) and diphenyl phosphate (BDP) as flame retardants, zinc borate(ZB) and organically modified montmorillonite(OMMT) as synergists. Vertical burning test, limiting oxygen index (LOI) and NBS smoke density test were used to evaluate the performance of TPU sheath material for low-smoke halogen-free flame retardant cables. Results showed that surface treated ATH had higher mechanical properties than the untreated ATH. Phosphate ester improve flame retardant performance of the material, and also reduce performance damage to TPU in the modification process. ZB and OMMT could improve flame retardant performance of TPU, and reduce smoke density of the material, but improvement effect of OMMT on flame retardant performance and smoke density was better than that of ZB.