Currently, the main insulation materials for building exterior walls in our country are polystyrene (PS) foam and polyurethane (PU) foam. Since PS and PU are flammable materials that produce a large amount of toxic smoke when burned, fires caused by them frequently occur, posing a significant threat to people's lives and property safety. In some developed industrial countries, their use has been restricted. Phenol-formaldehyde (PF) resin has excellent heat resistance, superior flame retardancy, high mechanical strength, good electrical insulation properties, and excellent high-temperature creep resistance. It is widely used in fields such as electronics, electrical engineering, aviation, and aerospace. Phenol foam, which is obtained by foaming phenol resin, also has advantages such as higher heat resistance temperature, better flame retardancy, and lower smoke and toxicity during combustion compared to PS and PU foams. It is a potential substitute for PU and PS foams. China's building energy-saving industry has now formed a market for exterior wall insulation systems with an annual output of 200 billion yuan, mainly using polystyrene foam. Among them, there are 2 billion square meters of newly completed buildings each year, and there are about 40 billion square meters of existing buildings with an annual renovation of about 2 billion square meters. If phenol-formaldehyde foam gradually replaces polystyrene foam and polyurethane foam, the market prospects are broad. A production line for producing 100,000 cubic meters of phenol-formaldehyde board per year requires an investment of about 5 million yuan.