| 摘要 |
PURPOSE:To obtain a film which can be suitably used as a base of flexible circuit board of high heat resistance and high precision and wiring density, because it has excellent mechanical properties and low thermal expansion coefficient by using a polyimide prepared from a specific stiff diaminobenzanilide as an amine component. CONSTITUTION:The subject polyimide film is obtained from a tetracarboxylic dianhydride and a diamine mixture containing 50 to 90mole% of 4,4'- diaminobenzanilide of the formula so that the shrinkage of the polyimide becomes -20 to +7.5% based on the polyamic acid film as a precursor. The thermal expansion coefficient a is -1X10<-5=alpha<=1X10<-5> at 30 to 100 deg.C The diamine used in combination with 4,4'-diaminobenzanilide is 4,4'-diaminodiphenyl, giving the film well balanced performance. |
