| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyimide excellent in power of adhesion to metal and having a low ionic impurities concentration and a method which can produce the same directly without the necessity for passing through a polyamic acid. SOLUTION: At least one first acid dianhydride is reacted with at least one first diamine, then, at least one second acid dianhydride and at least one second diamine are added to the reaction system so that the number of kinds of all the reactants is at least 4 and the numbers of kinds of all the acid anhydrides and those of all the diamines are at least 2, respectively, and the reaction is caused to proceed. The reaction is carried out in a heated polar solvent in the presence of a lactone polymerization catalyst, thus enabling the imidization to be realized directly without passing through a polyamic acid. The resultant polyimide has a wt. average mol.wt. of 20,000-100,000, an ionic impurities concentration of 0.1 ppm or lower, and an adhesive power (in thermal adhesion to 42 alloy) of 500μm/cm or higher.
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