Environment-friendly low-density polyurethane sandwich panel

The invention discloses an environment-friendly low-density polyurethane sandwich panel. The environment-friendly low-density polyurethane sandwich panel is a polyurethane color steel plate produced through a continuous production process of the polyurethane sandwich panel, the polyurethane color steel plate comprises a surface plate, a sandwich layer and a bottom plate, and the sandwich layer isprepared through the reaction of combined polyether and isocyanate, wherein the combined polyether is prepared from 20-35 parts of polyether polyol A, 30-45 parts of polyether polyol B, 5-20 parts ofpolyether polyol C, 5-15 parts of polyether polyol D, 5-10 parts of polyether polyol E, 1.5-3.0 parts of foam stabilizer, 0.8-1.5 parts of catalyst a, 1.3-2.0 parts of catalyst b, 1.0-1.6 parts of catalyst c, 11-20 parts of foaming agent and 1.8-2.2 parts of water. The environment-friendly low-density polyurethane sandwich panel adopts a foaming system mainly composed of cyclopentane, the energy is saved, the environment i