Aqueous polyurethane dispersion subjected to post-chain extension through click chemistry and preparation method thereof

The invention relates to an aqueous polyurethane dispersion subjected to post-chain extension through click chemistry and a preparation method thereof. The preparation method comprises the following steps: adding 25-35wt% of polytetrahydrofuran ether diol to a reactor, carrying out vacuum dehydration at 110-120 DEG C for 1-2.5 hours and reducing the temperature to 60-90 DEG C; adding 10-20wt% of aliphatic diisocyanate and reacting for 1-3 hours; adding 1-5wt% of chain extender containing carboxyl and reacting for 2-4 hours; adding 1-5wt% of acetone, reducing the temperature to 20-35 DEG C and adding 2-6wt% of triethylamine, thus obtaining a polyurethane prepolymer; cooling the polyurethane prepolymer to the room temperature, adding 1-5wt% of dithiol post-chain extender and reacting for 5-15 minutes; and then adding 40-50wt% of distilled water at a speed of 3000rpm and stirring the materials for 1-3 hours, thus obtaining the aqueous polyurethane dispersion subjected to post-chain extension through click chemistry. The preparation process is simple and is short in reaction time and low in energy consumption. The prepared product has good stability, high solid content, good low toxicity, environment friendliness and adhesive property and a broad application prospect.