Flame-retardant rigid polyurethane foam and preparation method thereof

The invention belongs to the technical field of flame-retardant polyurethane foam, and particularly relates to flame-retardant rigid polyurethane foam and a preparation method thereof. The flame-retardant rigid polyurethane foam is prepared from a black material and a white material, the white material comprises the following raw materials: polyether polyol, a phosphate flame retardant, an inorganic powder filler, a foam stabilizer, a foaming agent, a catalyst and a wetting dispersant, and the black material is isocyanate; the inorganic powder filler is composed of flame-retardant inorganic powder and an accelerant; the flame-retardant inorganic powder is calcium phosphate and silicon carbide, and the accelerant is aluminum oxide. The inorganic powder filler reacts at high temperature to generate a flame-retardant film, the flame-retardant film and the phosphate flame retardant play a promoting role, compared with traditional phosphorus-containing and halogen-containing flame retardance, the flame retardance,