Method for producing resin composition, and resin composition

A method of producing a resin composition, comprising:

• a washing step of washing the resin composition with water,
• the resin composition containing:
• fine polymer particles (A) which have a graft part that is constituted by a polymer containing, as one or more structural units, the one or more structural units derived from at least one type of monomer selected from the group consisting of aromatic vinyl monomers, vinyl cyanide monomers, and (meth)acrylate monomers;
• and
• a resin (B) which is, at 25° C., a liquid having a viscosity of 100 mPa s to 1,000,000 mPa·s, or a semisolid,
• in a case where a total amount of the fine polymer particles (A) and the resin (B) is regarded as 100% by weight, an amount of the fine polymer particles (A) being 1% by weight to 70% by weight and an amount of the resin (B) being 30% by weight to 99% by weight;
• further comprising:
• an agglutinating step of obtaining, from a latex, the resin composition as an agglutinate which contains the fine polymer particles (A) and the resin (B), by at least one type of method selected from the group consisting of flocculation with a flocculant, shearing, and freezing;
• the agglutinating step is carried out before the washing step;
• wherein the agglutinating step includes:
• a first agglutinating step of obtaining, from the latex which contains the fine polymer particles (A), an agglutinate which contains the fine polymer particles (A);
• and
• a second agglutinating step of obtaining the agglutinate which contains the fine polymer particles (A) and the resin (B), by mixing the resin (B) and the agglutinate which has been subjected to an intermediate washing step,
• wherein the method does not include a use of an organic solvent.