CATALYST COMPOSITION FOR PRODUCTION OF SYNDIOTACTIC POLYSTYRENE, ARYLETHYLENE POLYMER OR THEIR COPOLYMER

PROBLEM TO BE SOLVED: To obtain a catalyst composition for production of syndiotactic polystyrene or the like exhibiting more excellent catalyst activity and lower in cost than the conventional titanium metal catalyst including cyclopentadienyl ligands by directly utilizing a specific titanium complex, and bonding a specific cyclopentadienyl complex with a cocatalyst. SOLUTION: This catalyst composition is used for production of a poly (1 to 12C substituted) styrene or (poly)halogenated syndiotactic polystyrene or other arylethylene polymer, and the composition includes (A) 0.1 to 10 mole of a complex of the formula: TiR1'R2'R3' [R1' to R3' are each an alkyl (Y) or the like] or the formula: TiR1'R2'R3'R4' (R4' is R1'), (B) 0.1 to 10 mole of a complex of the formula: LnXRm [L is a group of the formula (R1 to R5 are each a substituent Y or the like) or the like; X is an element of group IIA(Z1), group IIIA(Z2); R is group Y or the like; n is 1 to 3 when X is the element Z2, X is the element Z1 then 1 to 2, m is 3-n when X is Z2, 2-n when X is Z1], and a cocatalyst for activated transition metal such as (C) 10 to 100,000 mole of methylalumoxane or the like.