METHOD FOR PRODUCING MODIFIED CONJUGATED DIENE-BASED POLYMER, POLYMER COMPOSITION, CROSS-LINKED PRODUCT, AND TIRE

1 . A method for producing a modified conjugated diene-based polymer, the method comprising:

polymerizing a monomer comprising a conjugated diene compound in the presence of an alkali metal compound or an alkali earth metal compound, to obtain a polymer having an active terminal;

reacting the polymer having an active terminal with a compound [M] having a plurality of hydrocarbyloxysilyl groups, to obtain a modified polymer; and

mixing the modified polymer with at least one compound [C]selected from the group consisting of a compound [N] having one hydrocarbyloxysilyl group and an alcohol having 6 to 20 carbon atoms.

2 . The method of claim 1 , wherein the mixing comprises mixing the modified polymer and the compound [C] without adding a condensation catalyst.

3 . The method of claim 1 , wherein the compound [M] is at least one selected from the group consisting of

a compound of formula (1) and a compound of formula (2):

wherein

R 1 is a hydrocarbylene group having 1 to 20 carbon atoms,

R 2 and R 3 each are independently a hydrocarbyl group having 1 to 20 carbon atoms,

A 1 is a group “*—C(R 5 )═N—” or a group “*—N═C(R 5 )—”, wherein R 5 is a hydrogen atom or a hydrocarbyl group, and “*” represents a bond for bonding to R 4 ,

R 4 is an m-valent hydrocarbon group having 1 to 20 carbon atoms or an m-valent group having at least one atom selected from the group consisting of nitrogen, oxygen and sulfur, and no active hydrogen, and having 1 to 20 carbon atoms,

n is an integer of 1 to 3, and

m is an integer of 2 to 10; and

and a compound of formula (2)

wherein

R 5 , R 12 and R 13 each are independently a hydrocarbylene group having 1 to 12 carbon atoms, and

R 6 , R 7 , R 8 , R 9 , R 10 and R 11 each are independently a hydrocarbyl group having 1 to 20 carbon atoms,

a, c and d each are independently an integer of 1 to 3, and

b is an integer of 1 to 10.

4 . The method of claim 1 , wherein the compound [N] has a molecular weight of 800 or less.

5 . The method of claim 1 , wherein the polymerizing comprises polymerizing the monomer in the presence of a compound obtained by mixing an alkali metal compound or an alkali earth metal compound and a compound having a functional group that interacts with silica.

6 . The method of claim 1 , wherein the monomer further comprises an aromatic vinyl compound.

7 . A modified conjugated diene-based polymer obtained by a method comprising:

polymerizing a monomer comprising a conjugated diene compound in the presence of an alkali metal compound or an alkali earth metal compound to obtain a polymer having an active terminal;

reacting the polymer having an active terminal and a compound [M] having a plurality of hydrocarbyloxysilyl groups to obtain a modified polymer; and

mixing the modified polymer and at least one compound [C] selected from the group consisting of a compound [N] having one hydrocarbyloxysilyl group and an alcohol having 6 to 20 carbon atoms.

8 . A polymer composition, comprising:

silica; and

a modified conjugated diene-based polymer obtained by the method of claim 1 .

9 . A cross-linked product obtained by a method comprising cross-linking the polymer composition of claim 8 .

10 . A tire, comprising:

a tread, a sidewall, or both, formed from the polymer composition of claim 8 .