PURPOSE: A composition reusing a used thermoplastic polyester resin, capable of preparing easily a thick-walled molded article having scaly pattern, obtained by blending thermoplastic polyester having adjusted water content with polypropylene resin in a specific ratio.

CONSTITUTION: A mixed resin of 20W70wt% thermoplastic polyester resin having an adjusted water content of 0.01W0.4wt%, consisting of ethylene terephthalate as a main repeating unit, having an intrinsic viscosity of ≥0.55, and 80W30wt% polypropylene resin is used as a synthetic resin component. A thick-walled molded article having scaly pattern produced resulting from the non-compatibility of both the resin in a molten state can be obtained by injection molding the mixed resin at a temperature between the melting points of the two resins, concretely, at 240W280°C.