Patent ID: 8404785

Claim:
A method for producing a modified conjugated diene polymer, comprising: (A) carrying out a primary modification reaction that reacts a component (a) with a conjugated diene polymer having a vinyl content of below 10% and a cis-1,4-bond content of 75% or more and possessing an active end to which component (a) is introduced to obtain a primary-modified conjugated diene polymer, and (B) carrying out a secondary modification reaction that reacts a component (b) with the primary-modified conjugated diene polymer to introduce component (b) into a functional group of the primary-modified conjugated diene polymer derived from the component (a) to obtain a secondary-modified conjugated diene polymer, wherein the component (a) is a heterocumulene compound that includes two or more functional groups shown by the general formula (1): X═C═Y in which X represents a carbon atom or a nitrogen atom, and Y represents an oxygen atom, a nitrogen atom, or a sulfur atom in the molecular structure, and the component (b) is an active hydrogen-containing compound that includes one or more functional groups selected from the group consisting of an amino group, an imino group, and a mercapto group, wherein the secondary modification reaction (B) utilizes a catalyst that promotes a reaction between the component (b) and the functional group of the primary-modified conjugated diene polymer derived from the component (a).