Polyimide precursor solution process for the production thereof coating or film obtained therefrom and process for producing the film

A process for the production of a polyimide precursor solution, which comprises reacting 1 mole of a diamine represented by the following general formula (3)

• H.sub.2 N--R'--NH.sub.2 ( 3)
• (wherein R' represents a divalent aromatic residue containing at least one 6-membered carbon ring) to react with 0.3 to 0.9 mole of a tetracarboxylic acid dianhydride represented by the following general formula (4) ##STR63## (wherein R represents a tetravalent aromatic residue containing at least one 6-membered carbon ring, wherein the four carbonyl groups are directly connected to different carbon atoms of R and each of two pairs of the four carbonyl groups is connected to adjacent carbon atoms in the 6-membered carbon ring) in a solvent to give a diamine represented by the general formula (1), ##STR64## (wherein R represents a tetravalent aromatic residue containing at least one 6-membered carbon ring, wherein the four carbonyl groups are directly connected to different carbon atoms of R and each of two pairs of the four carbonyl groups is connected to adjacent carbon atoms in the 6-membered carbon ring, and R' represents a divalent aromatic residue containing at least one 6-membered carbon ring), and
• adding 0.95 to 1.05 moles of the tetracarboxylic acid, tetracarboxylic ester, or a mixture thereof, represented by the general formula (2) ##STR65## (wherein R" represents a tetravalent aromatic residue containing at least one 6-membered carbon ring, wherein the four carbonyl groups are directly connected to different carbon atoms in the residue and each of the two pairs of the four carbonyl groups is connected to adjacent carbon atoms in the 6-membered carbon ring, and R'" represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms) to 1 mole of the thus obtained diamine.