| 摘要 |
PROBLEM TO BE SOLVED: To obtain a composition having excellent heat resistance and low hygroscopicity by selecting a composition prepared by mixing a plurality of polyimide resins prepared by cyclizing the products of an acid component with a diamine component in different molar ratios and having a specified glass transition temperature or blow and being soluble in an organic solvent. SOLUTION: This composition is one obtained by mixing a high-molecular- weight polyimide resin (A) with a low-molecular-weight polyimide resin (B) in a weight ratio in the range: 0.5<=A/(A+B)<=0.975, having a glass transition temperature of 350 deg.C or below and being soluble in an organic solvent. An acid component (e.g. 3,3',4,4'-biphenyltetracarboxylic dianhydride) is reacted with a diamine component (e.g.α,ω-bis(3-aminopropyl)polydimethylsiloxane in a ratio in the range: 0.95<=r1 <=1.05 to obtain a polyimide resin A and in a ratio in the range: 0.80<=r2 <=0.95 to obtain a polyimide resin B, r1 and r2 are each a ratio of the acid component to the diamine component by mole. The molecular weight is controlled by an end capping agent such as an acid dianhydride or an aromatic or aliphatic anine.
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