The film preparation method is as follows:
Polyamide acid solution flow forming film, stretching, high temperature imide. Thin film is yellow transparent, relative density 1.39-1.45, has outstanding high temperature resistance, radiation resistance, chemical corrosion resistance and electrical insulation properties, can be used in 250-280℃ air for a long time. The vitrification temperatures are 280℃ (Upilex R), 385℃ (Kapton) and above 500℃ (Upilex S), respectively. The tensile strength is 200MPa at 20℃ and greater than 100MPa at 200℃. It is especially suitable for flexible printed circuit board base material and insulation material of various high temperature resistant electric motor.
Thermosetting polyimides have excellent thermal stability, chemical resistance and mechanical properties and are usually orange in color. Graphite or glass fiber reinforced polyimide bending strength up to 345 MPa, bending modulus up to 20GPa. Thermosetting polyimide has little creep and high tensile strength. The use of polyimide temperature range covers a wide range from minus 100 degrees to two or three hundred degrees.
Polyimide is chemically stable. Polyimides do not require the addition of flame retardants to prevent combustion. Polyimides in general are resistant to chemical solvents such as hydrocarbons, esters, ethers, alcohols, and chlorofluorocarbons. They are also resistant to weak acids but are not recommended for use in strong alkali and inorganic acid environments. Some polyimides such as CP1 and CORIN XLS are soluble solvents, which helps to develop their applications in spraying and low temperature crosslinking.