METHOD FOR MANUFACTURING THERMOPLASTIC RESIN COMPOSITION

Provided is a method for manufacturing a thermoplastic resin composition that enables easy control of the weight average molecular weight of a thermoplastic resin and that is used as a material of a soluble material for three-dimensional modeling to be a support material, the support material having sufficient strength even when used in manufacture of a three-dimensional object by an FDM system 3D printer, being less colored to have excellent appearance quality, and having a high dissolution speed in neutral water to be quickly removable from a precursor of the three-dimensional object without use of a strong alkaline aqueous solution. The method for manufacturing a thermoplastic resin composition containing a thermoplastic resin that has dicarboxylic acid monomer units derived from a dicarboxylic acid component and that has a proportion of an aromatic dicarboxylic acid monomer unit derived from a sulfonic acid group and/or sulfonate group-containing aromatic dicarboxylic acid component in the dicarboxylic acid monomer units of 10 mol% or more, the method including mixing an organic salt compound represented by a following general formula (I). (R1-SO3-)nXn+(I)