The invention provides a method for preparing a
polyurethane adhesive used for building. The method comprises the following steps: 1) adding radix astragali
powder in water, boiling the material, insulating the material, adding absolute ethyl
alcohol, stirring the materials, cooling the materials, performing ultrasonic extraction to obtain a primary filtrate, adding filter residue in an
ethanol solution, performing ultrasonic extraction to obtain a secondary filtrate, merging the filtrates, performing rotary
evaporation concentration to obtain a radix astragali extract product; 2) performing
ultrasonic dispersion on porous
zinc phosphate and the radix astragali extract product,
drying the material to obtain an antibacterial filling material; 3) preparing an antibacterial solution, adding a
stearic acid solution, stirring the materials, performing pumping
filtration, washing and
drying the product to obtain the modified antibacterial filling material; 4) blending
polyol, a chain
extender, a stabilizing agent, an antifoaming agent and the modified antibacterial filling material under vacuum, adding a catalyst and stirring a mixture under vacuum to obtain a component A; 5) stirring diisocyanate and an activator under vacuum to obtain a component B; and 6) uniformly mixing the component A and the component B to obtain the
polyurethane adhesive used for building. The prepared
adhesive has good
antibacterial property.