Prefabricated building polyurethane sealant, and preparation method thereof

The invention relates to a prefabricated building polyurethane sealant, and a preparation method thereof. The prefabricated building polyurethane sealant comprises an anti-sagging agent; the anti-sagging agent is a hyperbranched polyurea formed via reaction of hyperbranched polyethylenimine with a single isocyanate terminated prepolymer, the hyperbranched polyethylenimine contains 10 to 30 nitrogen atoms, the single isocyanate terminated prepolymer is obtained via reaction of a diisocyanate monomer with a monohydric alcohol containing 3 to 12 carbon atoms. The prefabricated building polyurethane sealant possesses high adhesive force on cement and metal substrates, is high in flexibility, elongation percentage, and elastic resilience, is excellent in weather resistance, hydrolysis resistance, fatigue resistance, and thixotropic property, and is low in modulus; construction is convenient; and production technology is simple. 本发明涉及种装配式建筑聚氨酯密封胶及其制备方法，密封胶包含抗流挂剂，该抗流挂剂为超支化聚乙烯亚胺与单异氰酸酯封端预聚体反应形成的超支化聚脲，其中超支化聚乙烯亚胺的分子结构中含