Resin composition and use for same

A method of producing a resin composition, comprising:

• a step 1 of obtaining an aqueous latex containing fine polymer particles (A) and an emulsifying agent (C);
• a step 2 of obtaining, with use of the aqueous latex, slurry containing a coagulate of the fine polymer particles (A);
• a step 3 of taking out the coagulate from the slurry and adjusting a water content of the coagulate to not less than 10% with respect to a weight of the coagulate;
• and
• a step 4 of mixing the coagulate and a thermosetting resin (B),
• the fine polymer particles (A) containing a rubber-containing graft copolymer having an elastic body and a graft part grafted to the elastic body,
• the graft part being a polymer containing at least one type of structural unit derived from at least one type of monomer selected from the group consisting of aromatic vinyl monomers, vinyl cyanide monomers, and (meth)acrylate monomers,
• the step 2 further including a step of adding a resin (E) to the aqueous latex,
• the resin (E) being a liquid having a viscosity of 100 mPa·s to 1,000,000 mPa·s at 25° C., a semisolid, or a solid, and
• the step 4 further including:
• a step 4a of mixing the coagulate and the thermosetting resin (B) to obtain a mixture;
• a step 4b of stirring the mixture obtained in the step 4a to remove water from the coagulate;
• and
• a step 4c of further adding the thermosetting resin (B) to the mixture obtained in the step 4b and mixing the mixture obtained in the step 4b with the thermosetting resin (B).