A sandwich panel is one structure made of three layers of material: low density core inserted material in between two relatively thin steel skin layers.
Polyurethane Sandwich Panel also called PU Sandwich Panel, the up & down surface of this panel is Galvanized & Pre-painted steel sheets, core material is 5 components Polyurethane glue, it is formed by heating, foaming & laminating. Polyurethane is the best material for temperature keeping and sound insulation.