The invention belongs to the technical field of macromolecular waterborne
polyurethane, the method comprises the following steps: 1, mixing micromolecular
siloxane, deionized water, absolute ethyl
alcohol and acid, and reacting under the protection of
nitrogen to obtain a product I, namely hyperbranched organic
silicon with amino; 2, enabling diisocyanate, dihydric
alcohol and a catalyst to react under
inert atmosphere protection; then, adding a hydrophilic chain
extender, a cross-linking agent, a neutralizer and an
organic solvent for
continuous reaction to obtain primary waterborne
polyurethane; putting the primary waterborne
polyurethane and an amine chain
extender into water, uniformly mixing, and emulsifying to obtain a primary waterborne polyurethane
prepolymer emulsion; and 3, mixing the product I with the primary waterborne polyurethane
prepolymer emulsion for reaction, and removing the
organic solvent to obtain the hyperbranched organic amino
silicon modified waterborne polyurethane
emulsion. The prepared modified waterborne polyurethane emulsion has excellent mechanical properties, good
water resistance, low water absorption, good temperature change resistance, salt
fog resistance and the like.