Abstract: A method for producing a hydrogenated polymer composition including a hydrogenated conjugated diene modified polymer that has a boron-containing functional group, the method including: (1) anionically polymerizing a monomer including a conjugated diene in the presence of a reactive metal or reactive metal compound capable of causing anionic polymerization to produce a reactive terminal polymer (Z); (2) reacting the reactive terminal polymer (Z) obtained in (1) with a boric acid compound that has at least two partial structures represented by B—O—R (I), and in which at least one R bonded to an oxygen atom in the partial structure (I) has a Taft's steric parameter Es value of ?0.30 or less to obtain an unhydrogenated conjugated diene modified polymer having a boron-containing functional group; and (3) hydrogenating at least some of carbon-carbon double bonds contained in conjugated diene units included in the unhydrogenated conjugated diene modified polymer obtained in (2).

Abstract: A method for producing a polymer composition including modified polymers having a boron-containing functional group includes anionically polymerizing at least one monomer selected from the group consisting of conjugated dienes and aromatic vinyl compounds in the presence of an active metal or an active metal compound capable of catalyzing anionic polymerization to produce a terminal-active polymer (Z), and reacting the terminal-active polymer (Z) obtained with a boric acid compound having at least two or more partial structures represented by the formula B-O-R (B is boron, O is oxygen, and R is an organic group) and having a Taft’s steric parameter Es of -0.30 or less with respect to at least one of Rs bonded to the oxygen atom in the partial structures.