Urethane-modified polyimide resin solution

The present invention addresses the problem of providing a novel urethane-modified polyimide resin solution that uses absolutely no high boiling-point, highly hygroscopic polar solvent. A urethane-modified polyimide resin solution containing: a urethane-modified polyimide resin (A) containing 30-90 mol% of amide-imide units (i) constructed from a trimellitic acid derivative and an aromatic diisocyanate component and 10-70 mol% of urethane units (ii) constructed from a compound of a specific structure and an aromatic diisocyanate component, taking the total structural components of the urethane-modified polyimide resin (A) as 100 mol%; and one or more organic solvents (B) selected from the group consisting of cyclohexanone and cyclopentanone. 本发明的课题为提供种完全不使用高沸点且高吸湿性的极性溶剂的新颖的氨基甲酸酯改性聚酰亚胺系树脂溶液。种氨基甲酸酯改性聚酰亚胺系树脂溶液，含有氨基甲酸酯改性聚酰亚胺系树脂(A)以及有机溶剂(B)，将氨基甲酸酯改性聚酰亚胺系树脂(A)的全部构成成分设定为100摩尔％时，所述树脂(A)含有由偏苯三甲酸衍生物与芳香族二异氰酸酯成分构成的酰胺酰亚胺单元(i)30～90摩尔％、由特定结构的化合物与芳香族二异氰酸酯成分构成的氨基甲酸酯单元(ii)10～70摩尔％；有机溶剂(B)是选自于由环己酮及环戊酮构成的群组中的1种以上。