The invention provides an expansive fire retardant coating with high heat flux resistance and a preparation method thereof in a bid to solve the above technical problems. The invention provides for some technical schemes and one of which provides for an expensive fire retardant coating with high heat flux resistance, which comprises a primer coating and a top coating;
according to the parts by mass, the components of the top coating include 50-80 parts of epoxy resin, 20-40 parts of epoxy resin modifier, 10-25 parts of flame retardant, 25-45 parts of carbonizing agent, 20-40 parts of foaming agent, 10-30 parts of refractory fiber, 10-40 parts of inorganic filler, 5-15 parts of curing agent, 5-10 parts of defoaming agent and 5-10 parts of flame retardant. The invention while compared with the prior art, has some advantageous effects which includes that in the resin structure modified by silicone, the C-O bond is replaced by the Si-O bond, which improves the crosslinking density of the system. In the heating process, the Si-O bond with greater bond energy and polarity can shield the surrounding groups, prolong the time of thermal blocking effect when the material is heated, and reduce the heat transfer inside the material. Also, the flame retardant in the raw materials used in the invention will be thermally degraded before the epoxy resin after being heated, and a large amount of heat will be absorbed in the process of thermal degradation etc.
