Patent ID: 7138447

Claim:
A thermoplastic polymer composition comprising a block copolymer (a) having a polymer block (I) of a block copolymer, which may be hydrogenated, of an aromatic vinyl compound polymer block and a conjugated diene polymer block, and a polymer block (II) of a polyurethane formed of a high polymer polyol, a chain extender and an organic diisocyanate; at least one compound (b) selected from organic tin compounds, organic titanium compounds and tertiary amines; and at least one compound (c) of a phosphorus compound and a phenolic compound and satisfying the following conditions (A) to (E): (A): the high polymer polyol has a number average molecular weight of 500 to 10,000; (B): the content of nitrogen derived from the organic diisocyanate in the polymer block (II) is within the range of 1 to 6.5% by weight based on the total weight of the high polymer polyol, the chain extender and the organic diisocyanate; (C): the content of the compound (b) is from 0.1 ppm to 0.2% by weight based on the block copolymer (a); (D): the content of the compound (c) is from 1 ppm to 2% by weight based on the block copolymer (a); and (E): the melt viscosity of the thermoplastic polymer composition meets the following equation (I): 0.9 ≦ηa 2 /ηa 1 ≦1.4 (I) wherein ηa 1 means a melt viscosity of the thermoplastic polymer composition when the urethane bond contained therein reaches to dissociation equilibrium at 200° C. under the load of 490.3 N [50 kgf], and ηa 2 means a melt viscosity of the thermoplastic polymer composition when kept at 200° C. under the load of 490.3 N [50 kgf] for 60 minutes.