Patent ID: 8258226

Claim:
A manufacturing method of a composition for manufacturing a heat ray-shielding polyvinyl chloride film used for manufacturing a heat ray-shielding polyvinyl chloride film, comprising the steps of: obtaining a dispersion liquid by dispersing tungsten oxide nanoparticles expressed by a general formula WO x (satisfying 2.45≦x ≦2.999) and/or the composite tungsten oxide nanoparticles expressed by a general formula M y WO z (wherein M is one or more kinds of elements selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, Sn, Al, and Cu, satisfying 0.1≦y≦0.5, 2.2≦z≦3.0) and having a hexaboride crystal structure, and a dispersant, into an organic solvent having a boiling point of 120° or less; obtaining a mixture by mixing a plasticizer for manufacturing a polyvinyl chloride, into this dispersion liquid; and obtaining a composition for manufacturing the heat ray-shielding polyvinyl chloride film by using a vacuum distillation method and removing the organic solvent from this mixture until a concentration of the solvent is 5 wt % or less.