The present invention is a
thermoplastic elastomer composition which is obtained by dynamically crosslinking an
ethylene / Alpha-olefin / non-
conjugated polyene copolymer (A), a
polyolefin resin (B), 1-200 parts by
mass of a
softening agent (C) per 100 parts by
mass of the total of the
copolymer (A) and the resin (B), and a crosslinking agent (D) with use of a batch mixer under conditions satisfying the following conditions (1)-(4). (1) 50 <=P1 <=300 (In this connection, P1 is defined by formula (i). P1 = Gamma ave. * Log(t1) (i) (In formula (i), t1 represents the
retention time (sec) after the introduction of the crosslinking agent (D), and Gamma ave. represents the average rate (sec-1) of the shear rates Gamma at t1.)) (2) 900 <=P2 <=1450 (In this connection, P2 is defined by formula (ii). P2 = (Tave. + 273) * Log(t1) (ii) (In formula (ii), Tave. represents the average resin temperature (DEG C) after the introduction of the crosslinking agent (D), and t1 represents the
retention time (sec) after the introduction of the crosslinking agent (D).)) (3) -2.5 <=P3 <=1.5 (In this connection, P3 is defined by formula (iii). P3 = Log(t1 / t2) (iii) (In formula (iii), t1 represents the
retention time (sec) after the introduction of the crosslinking agent (D), and t2 represents the time (sec) necessary for the residual amount of the crosslinking agent (D) to be 1 ppm or less of the introduced amount thereof at the average resin temperature Tave. after the introduction of the crosslinking agent (D).)) (4) The crosslinking agent (D) is introduced into a batch mixer after the introduction of the
ethylene / Alpha-olefin / non-
conjugated polyene copolymer (A), the
polyolefin resin (B) and the
softening agent (C). A
thermoplastic elastomer composition according to the present invention is able to produce a molded body that has excellent appearance and excellent mechanical properties such as
rubber elasticity, while being capable of increasing the melt density and the
extrusion amount, thereby improving the productivity.