Polyester resin composition, molded article, and composite molded article

A composite molded article obtained by laser welding a molded article composed of a polyester resin composition having a crystallinity of 15% or more as calculated with fast scanning calorimetry by a calculation method, wherein the calculation method comprises using fast scanning calorimetry, said polyester resin composition is heated from 30° C. to 260° C. at 10000° C./second, then maintained at 260° C. for 0.1 second, then cooled to 80° C. at 5000° C./second, maintained at 80° C. for 0.1 second, then cooled to −70° C. at 5000° C./second, and then heated to 260° C. at 1000° C./second, after which the curve obtained is used to calculate said crystallinity,

• wherein said polyester resin composition comprises a polyester resin (A) as a main component and contains a metal component and glass fiber (C) in an amount of more than 0 part by mass and 100 parts by mass or less, with respect to 100 parts by mass of said polyester resin (A), wherein, with respect to a carboxyl end group amount of said polyester resin (A) and a metal component amount contained in said resin composition, a ratio expressed by said metal component amount/said carboxyl end group amount is 0.86 or more, and
• wherein an amount of inward warpage of the molded article is 0.45 mm or less, the inward warpage being measured by forming the polyester resin composition into a box-like test piece having a bottom square having a side length L2 of 30 mm, a height H2 of 30 mm and a thickness D2 of 1.5 mm, molding under conditions including a cylinder temperature of 260° C. and a mold temperature of 80° C. where a sprue and runner were cut off at a pin gate, and a remaining portion was used as the test piece, and exposing the molded article to an environment at 23% and 50% RH for 24 hours, and measuring the amount of inward collapse of the side the farthest from the side having the pin gate of the molded article.