Patent ID: 7053143

Claim:
A polyester-based resin composition which shows a lightness of 42 or more when made into pellets, the polyester-based resin composition being prepared by melt-blending: a polyamide resin (A) containing a phosphorus compound, which is produced by the polycondensation of a diamine component comprising 70 mol % or more of m-xylylenediamine and a dicarboxylic acid component comprising 70 mol % or more of adipic acid; a polyester resin (B) containing 50 to 400 ppm of an antimony compound on the basis of antimony atom; and at least one compound (C) selected from the group consisting of inorganic acid salts and hydroxides of group-1 or -2 metals of the periodic table and transition metals; and satisfying the following expressions (1) and (2): P 1×(M1/100)×B1×(M2/100)≧450 (1) C 2/P2≧1 (2) wherein: M1 is a concentration of the polyamide resin (A) based on a total of the polyamide resin (A) and the polyester resin (B), ranging from 3 to 40% by mass; M2 is a concentration of the polyester resin (B) based on the total of the polyamide resin (A) and the polyester resin (B), ranging from 60 to 97% by mass; P1 is a phosphorus atom concentration (ppm) in the polyamide resin (A); B1 is an antimony atom concentration (ppm) in the polyester resin (B); P2 is a molar amount (mol) of the phosphorus compound in the polyamide resin (A); and C2 is a molar amount (mol) of the compound (C).