Expandable graphite is a kind of graphite intercalation compound obtained by chemical or electrochemical treatment of natural graphite flakes as raw materials. Expandable graphite expands rapidly (up to 300 times) in volume under heating, which suffocates the flame, and at the same time generates expansions to isolate the flame, delay or interrupt the spread of the flame, and is non-combustible, flexible, and high in surface energy. , The strength of the carbonized layer is good. However, the volume and dosage of the expansion body should be selected appropriately. Tests show that 150um particles, 30% expansion ratio, and 5% dosage are the most suitable.