Polyester resin composition, light-reflector component containing same, light reflector, and method for producing polyester resin composition

A method for producing a polyester resin composition containing a polyester resin A, a metal organic acid salt B, and a polyfunctional glycidyl group-containing styrene-based polymer C, the method comprising the step of:

• adding a master pellet containing the metal organic acid salt B,
• wherein
• the polyester resin A contains 70 to 100% by mass of a polybutylene terephthalate resin and 0 to 30% by mass of a polyethylene terephthalate resin,
• the metal organic acid salt B is either one or both of an alkali metal organic acid salt and an alkaline earth metal organic acid salt,
• the master pellet contains either one or both of alkali metal atoms and alkaline earth metal atoms in an amount of 200 to 15000 mg/kg,
• the polyester resin composition contains either one or both of alkali metal atoms and alkaline earth metal atoms in an amount of 0.0005 to 0.05 parts by mass based on 100 parts by mass of the polyester resin A and contains the polyfunctional glycidyl group-containing styrene-based polymer C in an amount of 0.05 to 3 parts by mass based on 100 parts by mass of the polyester resin A, and
• the polyester resin composition may contain an inorganic filler in an amount of less than 1 part by mass based on 100 parts by mass of the polyester resin A.