Patent ID: 7169849

Claim:
A process for producing a thermoplastic elastomer composition, comprising, in a single-stage step, melting and kneading a mixture under heating to be dynamically crosslinked, wherein said mixture contains: (i) a hydrogenated block copolymer (a 1 ) with a number average molecular weight of 200,000 or above which is obtained by hydrogenating a block copolymer that has at least one polymer block A 1 comprising mainly a vinyl aromatic compound and at least one polymer block B 1 comprising mainly a conjugate diene compound, and a non-hydrogenated block copolymer (a 2 ) which has at least one polymer block A 2 comprising mainly a vinyl aromatic compound and at least one polymer block B 2 comprising mainly a conjugate diene compound, at a mass ratio of the hydrogenated block copolymer (a 1 ):the non-hydrogenated block copolymer (a 2 )=85:15 to 100:0; (ii) a non-aromatic rubber softening agent (b) at a ratio of 50 to 250 mass parts per 100 mass parts of the total of the hydrogenated block copolymer (a 1 ) and the non-hydrogenated block copolymer (a 2 ); (iii) a peroxide-crosslinkable olefin resin (c) with a density of 0.94 g/cm 3 or above at a ratio of 2.5 to 50 mass parts per 100 mass parts of the total of the hydrogenated block copolymer (a 1 ) and non-hydrogenated block copolymer (a 2 ); (iv) a peroxide-decomposable olefin resin (d) at the rate of 0.5 to 10 times by mass the mixture amount of the peroxide-crosslinkable olefin resin (c); and (v) an organic peroxide (e) and a crosslinking aid (f), wherein an injection-molded sheet obtained from said thermoplastic elastomer composition has a compression set when compressed for 22 hours at a compression rate of 25% according to JIS K-6262 at 100° C. of 43 or less, and at 120° C. of 50 or less.