Method for producing modified conjugated diene polymer, modified conjugated diene polymer, modified conjugated diene polymer composition, rubber composition and tire

1. A method of producing a modified conjugated diene polymer comprising

a polymerization step of obtaining a conjugated diene polymer containing a nitrogen atom in a polymer chain and having an active end by copolymerizing a conjugated diene compound and a nitrogen atom-containing vinyl compound or a conjugated diene compound, an aromatic vinyl compound and a nitrogen atom-containing vinyl compound by use of an alkali metal compound and/or an alkaline earth metal compound as a polymerization initiator, and

a modification step of reacting a modifier, which is a compound represented by the following formula (1), with the active end of the conjugated diene polymer:

wherein R 1 to R 4 each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms; R 5 represents an alkylene group having 3 to 10 carbon atoms; R 6 represents an alkylene group having 1 to 20 carbon atoms; m is an integer of 1 or 2; and n is an integer of 2 or 3.

2. The method of producing the modified conjugated diene polymer according to claim 1 , wherein an amount of the nitrogen atom-containing vinyl compound to be added is 0.5 to 100 moles based on 1 mole of the polymerization initiator.

3. The method of producing the modified conjugated diene polymer according to claim 1 , wherein the nitrogen atom-containing vinyl compound is a compound represented by the following formula (2) or (3):

wherein R 7 to R 9 each independently represent hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms; R 10 represents a single bond or a divalent hydrocarbon group having 1 to 6 carbon atoms, which may be interrupted by any of NR 13 , 0 and S in the middle of the chain; and

R 11 to R 13 each independently represent any selected from the group consisting of an alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms and a tri-substituted silyl group having an alkyl group having 1 to 30 carbon atoms and/or an aryl group having 6 to 30 carbon atoms on silicon;

wherein R 7 to R 10 are the same as defined in the formula (2); X represents a divalent hydrocarbon group having 3 to 10 carbon atoms, which may be interrupted by any of NR 14 , O and S in the middle of the chain and being a saturated ring forming portion in which all carbon-carbon bonds are single bonds or an unsaturated ring forming portion in which at least one of the carbon-carbon bonds is a double bond; and R 14 represents an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 30 carbon atoms.

4. A modified conjugated diene copolymer obtained by the method of producing the modified conjugated diene polymer according to claim 1 , wherein the modified conjugated diene polymer is modified from a conjugated diene polymer polymerized by copolymerizing a conjugated diene compound and a nitrogen atom-containing vinyl compound or a conjugated diene compound, an aromatic vinyl compound and a nitrogen atom-containing vinyl compound with a modifier, which is a compound represented by the following formula (1), with the active end of the conjugated diene polymer:

wherein R 1 to R 4 each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms; R 5 represents an alkylene group having 3 to 10 carbon atoms; R 6 represents an alkylene group having 1 to 20 carbon atoms; m is an integer of 1 or 2; and n is an integer of 2 or 3.

5. A method of producing a modified conjugated diene polymer comprising

a polymerization step of obtaining a conjugated diene polymer having an active end by polymerizing a conjugated diene or copolymerizing a conjugated diene with a copolymerizable monomer by use of an alkali metal compound or an alkaline earth metal compound as a polymerization initiator,

a modification step of modifying the active end by reacting a compound represented by the following formula (I) with the active end of the conjugated diene copolymer, and

a step of modifying a vinyl group of a main chain of the conjugated diene polymer with a silicon modification group having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxy group by a hydrosilylation reaction:

where R 21 to R 24 each independently represent an alkyl group or aryl group having 1 to 20 carbon atoms; R 25 represents an alkylene group having 1 to 10 carbon atoms; R 26 represents an alkylene group having 1 to 20 carbon atoms; p is an integer of 1 or 2; and q is an integer of 2 or 3.

6. The method of producing the modified conjugated diene polymer according to claim 5 , wherein the step of modifying a vinyl group of the main chain is a step of reacting a hydrosilane compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxy group with the conjugated diene polymer in the presence of a catalyst, after the active end is modified.

7. A modified conjugated diene polymer obtained by the production method according to claim 5 , wherein a polystyrene-equivalent number average molecular weight (Mn) determined by gel permeation chromatographic (GPC) measurement is 20,000 to 2,000,000, and

the modified conjugated diene polymer is modified from a conjugated diene polymer polymerized by polymerizing a conjugated diene or copolymerizing a conjugated diene with a copolymerizable monomer by modifying (i) an active end of the conjugated diene polymer by reacting a compound represented by the following formula (I) with the active end of the conjugated diene copolymer,

wherein R 21 to R 24 each independently represent an alkyl group or aryl group having 1 to 20 carbon atoms; R 25 represents an alkylene group having 1 to 10 carbon atoms; R 26 represents an alkylene group having 1 to 20 carbon atoms; p is an integer of 1 or 2; and q is an integer of 2 or 3, and (ii) a vinyl group of a main chain of the conjugated diene polymer with a silicon modification group having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxy group by a hydrosilylation reaction.

8. A modified conjugated diene polymer having a nitrogen atom-containing functional group in a main chain of the polymer, and a functional group having at least one secondary amino group, at least one alkoxysilyl group, and 3 to 6 branches on at least one of ends, wherein

the modified conjugated diene polymer is modified from a conjugated diene polymer polymerized by copolymerizing a conjugated diene compound and a nitrogen atom-containing vinyl compound or a conjugated diene compound, an aromatic vinyl compound and a nitrogen atom-containing vinyl compound with a modifier, which is a compound represented by the following formula (1), with the active end of the conjugated diene polymer:

wherein R 1 to R 4 each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms; R 5 represents an alkylene group having 3 to 10 carbon atoms; R 6 represents an alkylene group having 1 to 20 carbon atoms; m is an integer of 1 or 2; and n is an integer of 2 or 3.

9. A modified conjugated diene polymer composition comprising

0.5 to 300 parts by mass of a silica inorganic filler based on 100 parts by mass of a rubber component having 20 parts by mass or more of the modified conjugated diene polymer according to claim 4 .

10. The modified conjugated diene polymer composition according to claim 9 , comprising 5 to 200 parts by mass of the silica inorganic filler.

11. A modified conjugated diene polymer composition comprising

5 to 200 parts by mass of a filler, which is silica and/or carbon black, based on 100 parts by mass of a rubber component having 20 parts by mass or more of the modified conjugated diene polymer according to claim 4 .

12. A rubber composition obtained by subjecting the modified conjugated diene polymer composition according to claim 9 to crosslinking.

13. A tire comprising the rubber composition according to claim 12 .

14. A rubber composition obtained by subjecting the modified conjugated diene polymer composition according to claim 11 to crosslinking.

15. A tire comprising the rubber composition according to claim 14 .

16. A modified conjugated diene polymer composition comprising

0.5 to 300 parts by mass of a silica inorganic filler based on 100 parts by mass of a rubber component having 20 parts by mass or more of the modified conjugated diene polymer according to claim 7 .

17. A modified conjugated diene polymer composition comprising

0.5 to 300 parts by mass of a silica inorganic filler based on 100 parts by mass of a rubber component having 20 parts by mass or more of the modified conjugated diene polymer according to claim 8 .

18. A modified conjugated diene polymer composition comprising

5 to 200 parts by mass of a filler, which is silica and/or carbon black, based on 100 parts by mass of a rubber component having 20 parts by mass or more of the modified conjugated diene polymer according to claim 7 .

19. A modified conjugated diene polymer composition comprising

5 to 200 parts by mass of a filler, which is silica and/or carbon black, based on 100 parts by mass of a rubber component having 20 parts by mass or more of the modified conjugated diene polymer according to claim 8 .

20. A modified conjugated diene polymer having a nitrogen atom-containing functional group in a main chain of the polymer, and a functional group having at least one secondary amino group, at least one alkoxysilyl group, and 3 to 6 branches on at least one of ends, wherein

the modified conjugated diene polymer is modified from a conjugated diene polymer polymerized by polymerizing a conjugated diene or copolymerizing a conjugated diene with a copolymerizable monomer by modifying (i) an active end of the conjugated diene polymer by reacting a compound represented by the following formula (I) with the active end of the conjugated diene copolymer,

wherein R 21 to R 24 each independently represent an alkyl group or aryl group having 1 to 20 carbon atoms; R 25 represents an alkylene group having 1 to 10 carbon atoms; R 26 represents an alkylene group having 1 to 20 carbon atoms; p is an integer of 1 or 2; and q is an integer of 2 or 3, and (ii) a vinyl group of a main chain of the conjugated diene polymer with a silicon modification group having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxy group by a hydrosilylation reaction.