Provided is a method of producing a polyimide resin or a polyimide coating, which is capable of producing a polyimide resin or a polyimide coating, each having excellent heat resistance and mechanical properties and having low hygroscopicity, while suppressing foaming. Provided is also a method of producing a polyamic acid solution, in which not only foaming at the time of polyimide resin production can be suppressed, but also a polyimide resin that is excellent in heat resistance and mechanical properties and low in hygroscopicity is given. Provided is further a polyimide coating and a polyamic acid solution obtained from these methods, respectively. A polyamic acid obtained from a reaction between a tetracarboxylic acid dianhydride component and a diamine component is heated in a mixed solvent composed of N,N,N',N'-tetramethylurea and at least one solvent selected from specified aprotic polar organic solvents and specified glycol ethers, to yield a polyimide resin.
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