Film forming materials on coatings generally include: grease, natural resin, phenolic resin, asphalt, alkyd resin, amino resin, cellulose, perchloroethylene resin, olefin resin, acrylic resin, polyester resin, epoxy resin, polyurethane resin, elemental organic compounds, rubber, other (inorganic polymer, xylene resin, etc.). The film-forming materials are generally divided into two types: the first type in the film-forming process is called non transformed film-forming materials, which are thermoplastic, softened by heat and hardened after cooling. The other type refers to the change of composition and structure in the film-forming process, that is, the film-forming material forms a film with completely different composition and structure from the original film, which is called conversion type film-forming material. This type of film-forming material can polymerize into insoluble network polymer with different composition under the action of heat, oxygen or other substances. The function of film-forming material is to combine the pigment, filler and resin, It is the basis of coating, which determines the adhesion of coating to substrate and the physical, chemical and mechanical properties of coating.