▎ 摘　　要

NOVELTY - The preparation method of aqueous polyurethane emulsion involves: (1) putting macromolecular dihydric alcohol into reaction kettle, stirring and heating, carrying out vacuum dehydration on macromolecular dihydric alcohol, cooling, adding diisocyanate, stirring and heating, carrying out heat preservation reaction, cooling, adding hydrophilic chain extender and solvent, stirring and heating, reacting, cooling, adding micromolecular chain extender and solvent, stirring and heating, reacting, then cooling, adding salt forming agent and solvent, and stirring to obtain prepolymer. USE - The method is useful for preparing aqueous polyurethane emulsion, which is useful for preparing graphene aqueous polyurethane safety sleeve (claimed). ADVANTAGE - The graphene aqueous polyurethane safety sleeve prepared by the method has excellent strength, resilience, chemical resistance and puncture resistance. DETAILED DESCRIPTION - The preparation method of aqueous polyurethane emulsion involves: (1) putting 15-18 wt.% macromolecular dihydric alcohol into reaction kettle, stirring and heating at 100-110 degrees C, carrying out vacuum dehydration on macromolecular dihydric alcohol under pressure of -0.1 MPa to water content of below 0.03%, cooling to 40 degrees C, adding 2.5-4.5 wt.% diisocyanate, stirring and heating at 80-90 degrees C, carrying out heat preservation reaction for 2-3 hours, cooling to 50 degrees C, adding 0.7-0.8 wt.% hydrophilic chain extender and 4-4.5 wt.% solvent, stirring and heating at 80 degrees C, reacting for 3-4 hours, cooling to 50 degrees C, adding 0.2-0.8 wt.% micromolecular chain extender and 6-6.5 wt.% solvent, stirring and heating at 70-75 degrees C, reacting for 2-3 hours, then cooling to 10-20 degrees C, adding 0.6-0.65 wt.% salt forming agent and 10-11 wt.% solvent, and stirring for 30 minutes to obtain prepolymer; (2) introducing the prepolymer into dispersion kettle, then adding 1-3 %mass closed graphene, stirring for 0.5 hour at 400 rpm, adjusting the speed of rotating disc to 1200-1400 rpm, adding 54-56 %mass deionized water to prepolymer at constant speed, continuously stirring for 1 minute at high speed after the prepolymer is opened, and then reducing the rotating speed to 400 rpm and stirring for 3 hours; and (3) heating the emulsion obtained in step (2) at 30-35 degrees C, removing the solvent in emulsion under reduced pressure of -0.09 MPa to obtain product.