Abstract: In general, rigid polyurethane foam with an isocyanate index of 105-115 is used in the production of refrigerator doors in order to ensure the thermal insulation, strength and aesthetics required for the quality of refrigerator doors. Rigid polyurethane foam with a high isocyanate index of 120~130 was used for refrigerator doors, which is partly used in isocyanate technology, which is commonly used in building material panels, and related experiments proved that the deformation could be reduced by 33% without affecting the thermal insulation performance of the foam, and it is proved that the generation and attachment of an isocyanurate group inside the rigid polyurethane foam can improve the mechanical strength of the foam and suppress the deformation of the door. Finally, verified the experimental results of the method for determining the physical strength of the mechanism.

Key words: Polyurethane foam, Isocyanurate foam, Flexural strength, Flexural modulus