Halogen-free flame-retardant functional polyurethane sealant and preparation process thereof

The invention relates to the technical field of sealants, and discloses a halogen-free flame-retardant functional polyurethane sealant and a preparation process thereof.The polyurethane sealant is prepared by taking a polyurethane prepolymer, a flame-retardant modifier, an inorganic filler, a chain extender ethylene glycol, an ultraviolet absorbent and a plasticizer as raw materials through high-temperature mixing, wherein the polyurethane prepolymer is prepared by taking a polyethylene glycol derivative containing a rigid heterocyclic ring in the structure as a soft segment polymer and taking an isocyanate monomer as a hard segment, the flame retardant modifier is a POSS derivative grafted with a phosphorus-containing flame retardant in the structure, and the rigid heterocyclic ring and the POSS derivative are introduced into the polyurethane structure, so that the flame retardant property of the polyurethane is improved, and the flame retardant property of the polyurethane is improved. The prepared polyuret