▎ 摘　　要

NOVELTY - Preparing environmentally friendly air filtering non-woven fabric comprises (i) mixing polypropylene, electret masterbatch and polymer electret to obtain mixture, where weight ratio of polypropylene, electret masterbatch and polymer electret is 100:4-8:0.1-1, (ii) feeding mixture into screw extruder, melting and extruding it to form a melt through the screw extruder, (iii) placing melt at constant temperature in pipeline, measuring by the metering pump, spraying out through spinneret to form fibers, drawing fibers by hot air at constant temperature and pressure to form melt-blown cloth on the mesh curtain, and (iv) sequentially subjecting melt blown cloth to constant temperature infrared radiation heat treatment, 50,000-60,000 volts high-voltage electret treatment and cooling treatment and wounding to obtain air filtering non-woven fabric. The electret masterbatch is composed of polypropylene, few-layer graphene nanosheets, antioxidants, compatibilizers, and nucleating agents. USE - The fabric is useful as air filter material in personal care, medical protection, industrial gas filtration, engine gas filtration, clean room air filtration, air purifiers, and indoor fresh air systems (claimed). ADVANTAGE - The electret masterbatch improves electret degree of fiber, and improves storage stability of the charge and filtration performance. DETAILED DESCRIPTION - Preparing environmentally friendly air filtering non-woven fabric comprises (i) mixing polypropylene, electret masterbatch and polymer electret uniformly to obtain mixture, where weight ratio of polypropylene, electret masterbatch and polymer electret is 100:4-8:0.1-1, (ii) feeding mixture into screw extruder, melting and extruding it to form a melt through the screw extruder, (iii) placing melt at a constant temperature in the pipeline, measuring by the metering pump, spraying out through the spinneret to form fibers, drawing fibers by hot air at constant temperature and pressure to form melt-blown cloth on the mesh curtain, and (iv) sequentially subjecting melt blown cloth to constant temperature infrared radiation heat treatment, 50,000-60,000 volts high-voltage electret treatment and cooling treatment and wounding to obtain air filtering non-woven fabric. The electret masterbatch is composed of polypropylene, few-layer graphene nanosheets, antioxidants, compatibilizers, and nucleating agents; and preparation method of electret masterbatch comprises (a1) weighing 5 g magnesium oxide microcrystalline powder and placing it in alumina ceramic boat, placing ceramic boat containing the magnesia microcrystalline powder in the middle of the tube furnace, and closing the tube furnace, replacing air in the tube with argon, adjusting the flow of argon to a constant 100-120 ml/minute, gradually heating tube furnace to 920-1000 degrees C, and the heating rate is 8-10 degrees C/minute, raising temperature to target temperature, maintaining temperature for 10-30 minutes, switching atmosphere to mixed gas of methane and hydrogen, and flow rate of the mixed gas is constant at 60-72 ml/minutes, depositing few layers of graphene on surface of magnesium oxide crystallites, where deposition time is 90-100 minutes, switching atmosphere to argon, and naturally cooling tube furnace to room temperature to obtain dark gray powdery product, transferring dark gray powdery product into hydrochloric acid solution, stirring slowly for more than 12 hours to filter out the insoluble matter, washing with deionized water until no metal ions are detected in washing liquid to obtain black powder, ultrasonically dispersing black powder in a polyethylene glycol aqueous solution having mass fraction of 15%, filtering again to obtain the few-layer graphene nanosheets, where purity of the magnesium oxide microcrystalline powder is not less than 99.9%; volume ratio of methane and hydrogen in the mixed gas is 1:5, ultrasonic dispersion power is 200 W, and the ultrasonic time is 10-30 minutes, (a2) weighing components of the electret masterbatch according to the set ratio, adding into high-speed mixer and mixing for 1-3 minutes, and the mixing speed is 1000-2000 revolutions/minute to obtain a premix, melting premix and extruding by twin-screw extruder, where temperature of each zone of the screw is 190-230 degrees C, and the electret masterbatch is prepared by vacuum granulation. An INDEPENDENT CLAIM is also included for environmentally friendly air filtering non-woven fabric obtained by above method.