▎ 摘　　要

NOVELTY - Low smoke flame retardant base film comprises 60-80 wt.% thermoplastic polyurethane particles, 12-35 wt.% phosphorus nitrogen halogen-free flame retardant composition, 2-10 wt.% loaded flame retardant, 2-7 wt.% synergistic flame retardant, 0.2-1 wt.% other filler additives; the thermoplastic polyurethane particles are polyether thermoplastic polyurethane particles; the supported flame retardant includes graphene modified metal double hydroxide; the synergistic flame retardant includes ammonium polyphosphate compounded maleic anhydride-C9 copolymerized microsphere flame retardant, and the other filler additives includes lubricants, pigments, hindered phenolic antioxidants, hindered amine light stabilizers, and/or hydrolysis-resistant agents. USE - The low smoke flame retardant base film is used for environment-friendly floor leather layer and railway vehicle floor composite material, floor and indoor commercial floor. ADVANTAGE - The low smoke flame retardant base film is wear-resistant and scratch-resistant good, and excellent mechanical performance, flame-retardant UL-94 test reaches V0 level, ISO 5659-2single smoke box light density test Ds maximum value can reach 115, and satisfy highest level HL3 of the railway vehicle floor the flame retardant R10 requirement of the railway vehicle. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing low smoke flame retardant base film, comprising (i) taking the thermoplastic polyurethane particles, phosphorus nitrogen halogen-free flame retardant composition, loaded flame retardant, synergistic flame retardant, and other filler additives, and adding to the double -screw extruder for blending, extruding, cooling, and pelletizing to obtain thermoplastic polyurethane flame-retardant particles, (ii) fully drying the thermoplastic polyurethane flame-retardant particles on the dehumidifying and drying device, and (iii) using the thermoplastic polyurethane elastomer special casting forming device to cast the thermoplastic polyurethane flame retardant particles into film, where the temperature of each section temperature area of the double-screw extruder is 170-185°C, dehumidifying and drying device temperature at 80-90°C for 3-5 hours, where the thermoplastic polyurethane elastomer special casting forming device a section of cooling roller temperature at 30 ~ 40 degrees centigrade, second section cooling roller temperature is 8-12°C, each section of the screw temperature is 160-200°C, die head temperature is 185-19°C, and the thickness of the casting film is 300-850 m.