| 摘要 |
PURPOSE:To provide a polyimide of outstanding moisture and heat resistance, high elastic modulus and low linear expansion coefficient, suitable for base film for floppy disc and VTR tape, consisting mainly of two recurring units of each specific structural formula. CONSTITUTION:The objective polyimide consisting mainly of two recurring units of formulae I and II (molar ratio I/II is 70/30-30/70), respectively. These recurring units are constituted by using (A) diamino compound from (i) 30-70mol% of 2.2-bis[4-(4-aminophenoxy)phenyl]-propane of formula III and (ii) 70-30mol% of 3.3'-dimethyl-4,4'-diaminobiphyhenyl of formula IV and (B) biphenyl tetracarboxylic dianhydride (derivative) of formula V.
|
