High-stability self-extinction waterborne polyurethane dispersion and preparation method thereof

The invention discloses a high-stability self-extinction waterborne polyurethane dispersion and a preparation method thereof. The preparation method comprises the following steps: uniformly mixing polyalcohol, a polycarboxylic acid hydrophilic chain extender, a small molecule chain extender, more than two sulfonate hydrophilic chain extenders and a catalyst; one of the two or more sulfonate hydrophilic chain extenders is sodium sulfamate; adding diisocyanate to react until the NCO content of the system reaches a preset value of 4-7%; adding a neutralizing agent for reaction to obtain a waterborne polyurethane prepolymer, and then adding a silane coupling agent for reaction; cooling to room temperature, adding an organic solvent to reduce viscosity, adding water, and stirring for emulsification; adding an amine micromolecule chain extender to carry out post chain extension; and carrying out reduced pressure distillation to remove the solvent to obtain the high-stability self-extinction waterborne polyurethane