| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing high-purity 2,3,3',4'-biphenyltetracarboxylic acid dianhydride (a-BPDA) suitable for production of a polyimide. SOLUTION: The method for producing the 2,3,3',4'-biphenyltetracarboxylic acid dianhydride in a powder shape involves heating 2,3,3',4'-biphenyltetracarboxylic acid in an inert gas atmosphere at 180-195°C for a time sufficient for finishing the conversion to anhydride to convert the acid to the anhydride. COPYRIGHT: (C)2007,JPO&INPIT
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