Preparation method of high-storage-stability polyester-type polyurethane prepolymer

The invention relates to a preparation method of a high-storage-stability polyester-type polyurethane prepolymer, which comprises the following steps: adding a nitrogen-containing metallic ion complexing agent into a hydroxyl-terminated low-polymer polyester polyol; dewatering at 95-130 DEG C under the vacuum degree of 0.08-0.09 MPa for 2 hours; cooling to 30-55 DEG C, mixing with 2,4-toluene diisocyanate, and reacting at controlled temperature of 30-65 DEG C for 0.5 hour; heating to 70-95 DEG C, and keeping the reaction for 2 hours; adding a polymerization inhibitor, and deaerating at controlled temperature of 70-95 DEG C under the pressure of 0.08-0.09 MPa for 0.5 hour to obtain the high-storage-stability polyester-type polyurethane prepolymer; and after measuring that the percentage ofNCO (isocyanate-group) in the prepolymer is equivalent to a set value, cooling, charging nitrogen, and storing in a closed environment. The change rate of the percentage of NCO in the obtained polyester-type polyurethane prep