| 摘要 |
PROBLEM TO BE SOLVED: To obtain a polyimide having high heat resistance, low dielectric- constant, low refractive index, and low birefringence by using a specific aromatic diamine compound. SOLUTION: This aromatic diamine compound is represented by formula I, wherein m and n are each an integer of 1-4; R1 and R2 are each H, F, CF3, 1-20C alkyl or 6-20C aryl; R3 and R4 are each H, F, CF3, 1-20C alkyl, 5-20C cyclic alkyl or the like; and R5 and R6 are each H, F, CF3, 1-20C alkyl, 5-20C cyclic alkyl, 6-20C aryl or the like. Preferably, at least either R3 or R4 in formula I is represented by formula II, wherein k is an integer of 4-19; l is an integer of 1-5; and Rf is H, F, CF3. Since this diamine compound has bulky groups as side chains and amino groups via ether groups in the main chain, the mol.wt. of a diamine structural unit is high and the density of imide group, which increases the dielectric constant is low.
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