Process producing a polymer comprising an unsaturated carboxylic acid or a derivative thereof

A process for producing a polymer comprising a monomer selected from the group consisting of an unsaturated carboxylic acid, an anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, a salt of an unsaturated carboxylic acid, an amide of an unsaturated carboxylic acid, a nitrile of an unsaturated carboxylic acid, an allyl glycidyl ether and a methallyl glycidyl ether, the process comprising subjecting a starting mixture containing (a) said monomer and (b) a mixture of a water-soluble organic solvent and water to polymerization in the presence of a polymerization catalyst,

• wherein the starting mixture contains said monomer at a concentration of 50 to 700 g per liter of the total volume of (a) said monomer and (b) the mixture of the water-soluble organic solvent and water,
• wherein the volume ratio of the water-soluble organic solvent (A) to water (B) is (A):(B)=1:9 to 9:1, and
• wherein the polymerization catalyst is at least one member selected from the group consisting of
• (1) a metal compound represented by the formula (1)
• L.sub.p.M.X.sub.q ( 1)
• wherein M is a member selected from the group consisting of Ti, Zr, Hf and V;
• L is at least one member selected from the group consisting of a cyclopentadienyl group, an indenyl group, a fluorenyl group, methylcyclopentadienyl, 1,2-dimethylcyclopentadienyl, 1,3-dimethylcyclopentadienyl, pentamethylcyclopentadienyl, n-butylcyclopentadienyl, tertbutylcyclopentadienyl, trimethylsilylcyclopentadienyl, 3-methylindenyl, 4-methylindenyl, 5-methylindenyl, 5-ethylindenyl and 4,7-dimethylindenyl;
• X is at least one member selected from the group consisting of a halogen atom, a hydrogen atom, a lower alkyl group, a lower alkoxy group, an aryloxy group, a phenyl group and a benzyl group;
• p represents an integer of at least 1, q represents an integer including 0 and the sum of p and q equals the valence of M, and
• (2) a metal compound represented by the formula (2)
• R.M.Y.sub.r ( 2)
• wherein M is a member selected from the group consisting of Ti, Zr, Hf and V;
• R is a group formed by bonding two identical or different groups selected from the group consisting of a cyclopentadienyl group, an indenyl group, a fluorenyl group, methylcyclopentadienyl, 1,2-dimethylcyclopentadienyl, 1,3-dimethyl-cyclopentadienyl, pentamethylcyclopentadienyl, n-butylcyclopenta-dienyl, tert-butylcyclopentadienyl, trimethylsilylcyclopentadienyl, 3-methylindenyl, 4-methylindenyl, 5-methylindenyl, 5-ethylindenyl and 4,7-dimethylindenyl, the two groups being bonded to each other via a lower alkylene or di(lower alkyl)silylene group;
• Y is at least one member selected from the group consisting of a halogen atom, a hydrogen atom, a lower alkyl group, a lower alkoxyl group, an aryloxy group, a phenyl group and a benzyl group;
• r is equal to (n-2) wherein n is the valence of M.