PURPOSE: To obtain a radio wave absorber having good heat resistance and flame retardance by using a polyimide film containing a specific quantity of carbon black.
CONSTITUTION: A radio wave absorber comprises a polyimide film containing 25 to 45wt.% carbon black. Also, the radio wave absorber is obtained by putting the carbon black of 25 to 45wt.% to the obtained polyimide in a polyimide acid solution and forming the polyimide acid solution in a film shape and then softening it in the polyimide. Therefore, since the carbon black has excellent radio wave absorption characteristics and the polyimide has good heat resistance and flame retardance, an electromagnetic wave leaked out of electronic equipment can be absorbed to attenuate it. Further, an external shape of the radio absorber is not deformed even in a high-temperature environment and the radio wave absorber is not burned easily even if exposed to flames.
Eiichiro Kuribayashi
Hirosaku Nagano
