▎ 摘　　要

NOVELTY - Polyurethane resin comprises 1-10 pts. wt. graphene, 200-220 pts. wt. macromolecular diol, 30-40 pts. wt. dimethylolpropionic acid, 50-80 pts. wt. N-methylpyrrolidone, 80-100 pts. wt. diisocyanate, 550-750 pts. wt. deionized water, 30-40 pts. wt. acetone, 0.5-1 pt. wt. catalyst and 1-2 pts. wt. crosslinking agent. USE - As polyurethane resin. ADVANTAGE - The polyurethane resin has high stability. The method increases the tensile strength of polymer emulsion film. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the polyurethane resin, involving (i) mixing graphene, macromolecular diol, N-methylpyrrolidone and deionized water, adding to a reaction kettle, stirring and heating at 70-100 degrees C to obtain a mixture, (ii) slowly dripping the mixture onto diisocyanate, heating at 90-95 degrees C, and maintaining the temperature for 3-4 hours, (iii) cooling the reaction product to 40-45 degrees C, adding dimethylolpropionic acid, reacting for 60-80 minutes, adding acetone, rapidly cooling to 10-15 degrees C, and carrying out high-speed stirring reaction for 4-5 hours to obtain aqueous polyurethane dispersion, (iv) adding catalyst to the aqueous polyurethane dispersion, stirring and heating at 70-80 degrees C, reacting for 100-150 minutes, cooling to 10-20 degrees C, and stirring for 30 minutes to obtain a prepolymer, (v) transferring the prepolymer to emulsifier, adding crosslinking agent, rapidly stirring the mixture for 40 minutes, adding catalyst, and continuously stirring at high speed for 5 minutes to obtain a prepolymer emulsion, and (vi) heating the prepolymer emulsion at 40-50 degrees C and removing acetone in the emulsion under the condition of -0.09 MPa to obtain the product.