Method for producing modified conjugated diene-based polymer, modified conjugated diene-based polymer, polymer composition, crosslinked body, tire and compound

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

reacting a conjugated diene-based polymer having an active chain end, obtained by polymerizing a monomer comprising a conjugated diene compound in the presence of an initiator that comprises at least either of an alkali metal compound or an alkaline earth metal compound, with a compound [M] having at least two groups selected from the group consisting of a group “—C(R 1 )═N-A 1 ” and a group “—N═C(R 1 )-A 1 ”, where R 1 is a hydrogen atom or a hydrocarbyl group and A 1 is a monovalent group having an alkoxysilyl group.

2. The method according to claim 1 , wherein the compound [M] is a compound of formula (1):

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

R 4 is an alkanediyl group having 1 to 20 carbon atoms, and

A 2 is a group “*—C(R 1 )═N—” or a group “*—N═C(R 1 )—”, where R 1 is a hydrogen atom or a hydrocarbyl group and “*” represent a bond to R 5 ;

R 5 is an m-valent hydrocarbyl group having 1 to 20 carbon atoms or an m-valent group having 1 to 20 carbon atoms, which has at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom and does not have an active hydrogen;

n is an integer of 1 to 3 and

m is an integer of 2 to 10; and

a plurality of R 2 , R 3 , R 4 , A 2 , and n are optionally the same or different.

3. The method according to claim 1 , wherein, on a gel permeation chromatography (GPC) curve obtained from measurement by GPC after the reacting, an area of peak portion(s) showing 2.5 times or more peak top molecular weight than a peak top molecular weight at a peak having a smallest molecular weight is 40% or more of a total peak area of the GPC curve.

4. The method according to claim 1 , wherein a peak top molecular weight at a peak having a smallest molecular weight measured by gel permeation chromatography (GPC) after the reacting is from 5.0×10 4 to 1.0×10 6 .

5. The method according to claim 1 , wherein the monomer further comprises an aromatic vinyl compound.

6. The method according to claim 1 , wherein the monomer is polymerized with a mixture of at least either of an alkali metal compound or an alkaline earth metal compound and a compound having a functional group that interacts with silica, as the initiator.

7. A modified conjugated diene-based polymer, comprising: a conjugated diene-based polymer having an active chain end and a compound [M] having at least two groups selected from the group consisting of a group “—C(R 1 )═N-A 1 ” and a group “—N═C(R 1 )-A”, where R 1 is a hydrogen atom or a hydrocarbyl group and A 1 is a monovalent group having an alkoxysilyl group,

wherein the modified conjugated diene-based polymer is a reaction product between the conjugated diene-based polymer and the compound [M].

8. A modified conjugated diene-based polymer of formula (3):

wherein R 2 is a hydrocarbyl group having 1 to 20 carbon atoms, R 6 is a hydrocarbyloxy group having 1 to 20 carbon atoms or a modified or unmodified conjugated diene-based polymer chain, R 4 is an alkanediyl group having 1 to 20 carbon atoms, and Z is a group represented by the following formula (4) or (5), R 5 is an m-valent hydrocarbyl group having 1 to 20 carbon atoms or an m-valent group having 1 to 20 carbon atoms, which has at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom and does not have an active hydrogen; n is an integer of 1 to 3 and m is an integer of 2 to 10, and a plurality of R 2 , R 4 , R 6 , Z, and n are optionally the same or different:

wherein R 1 is a hydrogen atom or a hydrocarbyl group and Poly is a modified or unmodified conjugated diene-based polymer chain; and “*” represents a bond to R 5 .

9. A polymer composition, comprising:

a modified conjugated diene-based polymer obtained by the method according to claim 1 ,

silica, and

a crosslinking agent.

10. A crosslinked body, comprising:

the polymer composition according to claim 9 ,

wherein the crosslinked body is obtained by crosslinking the polymer composition.

11. A tire, comprising:

the polymer composition according to claim 9 ,

wherein at least a tread of the tire or a sidewall of the tire is formed with the polymer composition.

12. A polymer composition, comprising:

the modified conjugated diene-based polymer according to claim 7 , silica, and

a crosslinking agent.

13. A crosslinked body, comprising:

the polymer composition according to claim 12 ,

wherein the crosslinked body is obtained by crosslinking the polymer composition.

14. A tire, comprising:

the polymer composition according to claim 12 ,

wherein at least a tread of the tire or a sidewall of the tire is formed with the polymer composition.

15. A polymer composition, comprising:

the modified conjugated diene-based polymer according to claim 8 , silica, and

a crosslinking agent.

16. A crosslinked body, comprising:

the polymer composition according to claim 15 ,

wherein the crosslinked body is obtained by crosslinking the polymer composition.

17. A tire, comprising:

the polymer composition according to claim 15 ,

wherein at least a tread of the tire or a sidewall of the tire is formed with the polymer composition.