▎ 摘　　要

NOVELTY - Coating comprises 100 pts. wt. polytetramethylene ether glycol, 25-45 pts. wt. isophorone diisocyanate, 30-50 pts. wt. hydroxy polylactic acid, 7-15 pts. wt. nano graphene oxide, 0.15-0.3 pts. wt. dibenzoyl peroxide, 4-8 pts. wt. tetrahydrofuran, 2-6 pts. wt. chain extender, 16-20 pts. wt. acetone, 4-10 pts. wt. triethylamine, 0.02-0.5 pts. wt. catalyst, 2-4 pts. wt. defoaming agent, 1-3 pts. wt. leveling agent, 9-15 pts. wt. deionized water and 40-60 pts. wt. inorganic filler. USE - Used as coating. ADVANTAGE - The coating is environmentally friendly, waterproof, non-toxic and is harmless; introduces active groups i.e. ester bond and carboxy group; and improves the biodegradability and compatibility. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing coating, comprising (i) dissolving the terminal hydroxy polylactic acid in tetrahydrofuran, and then heating to 100-140 degrees C, introducing nano graphene oxide and dibenzoyl peroxide, stirring under inert gas for 30-60 hours to obtain graphene grafted polylactic acid; (ii) drying polytetramethylene ether glycol in a vacuum environment of 100-120 degrees C until the water content drops to 60%, adding isophorone diisocyanate and catalyst at 65-75 degrees C, under an inert gas atmosphere of 0.1 MPa and performing a nucleophilic addition reaction to obtain polyurethane prepolymer; (iii) blending polyurethane prepolymer, graphene grafted polylactic acid and chain extender, stirring at 70 degrees C for 1-3 hours, during the reaction, continuously adding acetone, reducing the viscosity, reacting to -NCO at the content of less than 3% and dispersing in deionized water to obtain a polylactic acid-embedded polyurethane composition emulsion; and (iv) adding triethylamine to polylactic acid-embedded polyurethane composition emulsion at 40 degrees C, performing a neutralization reaction, adding defoaming agent, leveling agent and inorganic filler, stirring at 3000-5000 revolutions/minute for 1 hour and simultaneously performing ultrasound-assisted dispersion.