Insulating boards are a general term for organic high polymers containing two or more epoxy groups. Their relative molecular masses are not high except for a few. The molecular structure of epoxy resins is characterized by the presence of active epoxy groups within the molecular chains, which can be located at the end, middle, or in a ring-shaped structure. Due to the presence of active epoxy groups in their molecular structure, they can undergo cross-linking reactions with various hardeners, forming insoluble, non-melting high polymers with a three-dimensional network structure.