Resin composition, method for producing resin composition, and insulated electrical wire

A method for producing a resin composition containing a polyamic acid and a solvent, the polyamic acid having a repeating unit represented by the following general formula (1) in a molecular chain, the molecular chain having a structure represented by the following general formula (2) at one end or both ends, the method comprising:

• polymerizing an acid dianhydride represented by the following general formula (3) and a diamine compound represented by the following general formula (4) in the presence of an aprotic polar solvent and a reaction control agent,
• wherein the content of the reaction control agent relative to 100 mole of the acid dianhydride is 0.1 mol or more and 300 mol or less in the polymerization:
• wherein, in general formula (1), R1 is a tetravalent organic group;
• and R2 is a divalent organic group;
• wherein, in general formula (2), R1 is as defined for R1 in general formula (1);
• R1 in general formula (2) may be the same as or different from R1 in general formula (1);
• R3 is an organic group having 15 or less carbon atoms;
• in the case where both ends of the molecular chain has a structure of general formula (2), the two R1 may be the same as or different from each other and the two R3 may be the same as or different from each other;
• and * represents a binding site to a portion different from the structure represented by general formula (2) in the molecular chain;
• wherein, in general formula (3), R1 is as defined for R1 in general formula (1);
• H2N—R2—NH2 (4)
• wherein, in general formula (4), R2 is as defined for R2 in general formula (1), and
• wherein a weight average molecular weight of the polyamic acid is from 15,000 or more to 100,000 or less, a number average molecular weight of the polyamic acid is from 8,000 or more to 50,000 or less, and a ratio of the weight average molecular weight to the number average molecular weight of the polyamic acid is 2.3 or less, and
• wherein a viscosity of the resin composition at 30° C. measured by a B-type viscometer is from 10,000 cps or more to 100,000 cps or less.