Process for producing a styrene polymer having high degree of syndiotactic configuration

Claim 1

A process for producing a styrene polymer having a syndiotacticity in which the proportion of racemic diad is at least 75%, which comprises: polymerizing a styrenic monomer in the presence of a catalyst comprising as primary ingredients (A) a transition metal compound Formula (I): M 1 R 1 R 2 R 3 R 4 , wherein M 1 is titanium; R 1 ; R 2 , R 3 and R 4 are each a cyclopentadienyl group, a substituted cyclopentadienyl group, alkoxy or halogen; (B) a coordination complex compound of the formula: ([L.sup.2 ]) .sup.g+).sub.h ([M.sup.3 X.sup.1 X.sup.2 ------X.sup.n ].sup.(n-m-)-).sub.i, wherein L 2 is m 4 , which is a metal selected from Groups VIII to XII of the Periodic Table, R 5 R 6 M 5 or R 7 3 C, wherein M 5 is a metal selected from Groups VIII to X of the Periodic Table, R 5 and R 6 are each a cyclopentadienyl group, a substituted cyclopentadienyl group, indenyl or fluorenyl and R 7 is alkyl; M 3 is boron; X 1 to X n are each a member selected from the group consisting of phenyl, p-tolyl, benzyl, 4-tert-butylphenyl, 2,6-di-methylphenyl, 3,5-dimethylphenyl, 2,4-dimethylphenyl, 1,2-dimethylphenyl, pentafluoropheynyl, and 3,5-di(trifluoromethyl) phenyl; m is the valency of M 3 and is an integer of 1 to 7; n is an integer of 2 to 8; g is the ion valency of [L 2 ], wherein the integer of the valency state ranges from 1 to 7; h is an integer of 1 or more and i=hxg/(n-m); and (C) a compound selected from the group consisting of R 8 3 Al, R 8 2 Mg and R 8 2 Zn, wherein R 8 is an alkyl group of 1 to 8 carbon atoms.