THERMOPLASTIC POLYESTER ELASTOMER, RESIN COMPOSITION CONTAINING SAID ELASTOMER, AND MOLDED ARTICLES OBTAINED FROM THESE

The present invention aims to provide a thermoplastic polyester elastomer having particularly excellent extrusion moldability and extrusion molding stability, from which a hollow and long molded article can be stably produced with a uniform thickness for a long time. A polyester elastomer comprising a hard segment made of a polyester constituted of an aromatic dicarboxylic acid and an aliphatic or alicyclic diol and a soft segment made of an aliphatic polycarbonate, wherein the hard segment and the soft segment are bonded to each other, wherein the polyester elastomer is at least partially end-capped with a reactive compound, wherein the reactive compound comprises a polycarbodiimide, wherein the polyester elastomer has an acid value of 15 eq/ton or less, and wherein, under a condition of 230°C, the polyester elastomer satisfies (i) the melt viscosity at a shear rate of 10/sec after a preheating time of 5 minutes is 1, 800 Pa·s or more, and the melt viscosity at a shear rate of 1,000/sec after a preheating time of 5 minutes is 800 Pa·s or less; and (ii) a ratio of the melt viscosity measured at a shear rate of 10/sec after a preheating time of 5 minutes to the melt viscosity measured at a shear rate of 10/sec after a preheating time of 25 minutes is 0.7 to 1.3.