| abstract |
(57) [Abstract] [Purpose] Forming a polyimide coating film used as an insulating film / protective film for electric / electronic devices or a liquid crystal alignment film by coating a solution of polyimide and / or polyimide precursor on a substrate. A polyimide varnish for use in forming a smooth polyimide coating film, and a method of using the varnish. [Structure] Polyimide and / or polyimide precursor is dissolved in an organic solvent, the solution is applied on a supporting substrate, and heat treatment is performed to form a polyimide coating film on the supporting substrate. In the varnish, 5-60% by weight of the organic solvent is of the general formula [I] (In the formula, n is 1 or 2, and R represents hydrogen, an alkyl group having 1 to 4 carbon atoms, an alkenyl group, and an alkanoyl group.) A propylene glycol derivative represented by the formula: varnish. |