Method for producing modified conjugated diene based (co)polymer, modified conjugated diene based (co)polymer, and rubber composition

1. A method for producing a modified conjugated diene based (co)polymer, comprising

reacting a conjugated diene based (co)polymer with a metal halide compound to obtain a modified conjugated diene based (co)polymer,

wherein the conjugated diene based (co)polymer has a weight-average molecular weight of 150,000 to 2,000,000, and is obtained by a process comprising bonding, to a polymer having at least a conjugated diene unit, an alkoxysilyl group and an optionally protected primary amino group,

wherein the metal halide compound is hydrolyzed to obtain a hydrogen halide prior to reacting with the conjugated diene based (co)polymer.

2. The method for producing a modified conjugated diene based (co)polymer, set forth in claim 1 , wherein the polymer having at least a conjugated diene unit is a homopolymer of a conjugated diene, or a copolymer of a conjugated diene and an aromatic vinyl compound.

3. The method for producing a modified conjugated diene based (co)polymer, set forth in claim 1 , wherein the metal halide compound is a compound which generates hydrogen halide upon hydrolysis.

4. The method for producing a modified conjugated diene based (co)polymer, set forth in claim 1 , wherein the metal halide compound is a compound which comprises at least one kind of metal atom selected from the group consisting of silicon (Si), tin (Sn), aluminum (Al), zinc (Zn), titanium (Ti) and zirconium (Zr).

5. The method for producing a modified conjugated diene based (co)polymer, set forth in claim 1 , wherein the metal halide compound is at least one kind of compound selected from the group consisting of trimethylsilyl chloride, dimethyldichlorosilane, methyltrichlorosilane, silicon tetrachloride, methyldichlorosilane, tin tetrachloride, diethyl aluminum chloride, ethyl aluminum sesquichloride, ethyl aluminum dichloride, zinc chloride, titanium tetrachloride, titanocene dichloride, zirconium tetrachloride and zirconocene dichloride.

6. The method for producing a modified conjugated diene based (co)polymer, set forth in claim 1 , wherein the conjugated diene based (co)polymer is a polymer obtained by the following reaction (I):

adding an initiator containing at least either of an organic alkali metal and an organic alkaline earth metal to a hydrocarbon solvent containing a conjugated diene or a conjugated diene and an aromatic vinyl compound; subjecting the mixture to anionic polymerization to obtain a polymer; and reacting the polymerization active terminal of the polymer obtained with at least one kind of compound selected from a compound represented by the following general formula (1) and a compound represented by the following general formula (2):

wherein in formula (1), R 1 is an alkylene group having 1 to 12 carbon atoms; R 2 and R 3 are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group; R 4 , R 5 and R 6 are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group, or two of them may bond to each other to form a ring containing a Si atom to which they bond; g is an integer of 1 to 2; and f is an integer of 1 to 10, and

wherein in formula (2), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 have the same definitions as given above; and e is an integer of 1 to 2.

7. The method for producing a modified conjugated diene based (co)polymer, set forth in claim 1 , wherein the conjugated diene based (co)polymer is reacted with the metal halide compound of such an amount that the total mols of the halogen atom becomes 1 to 10 times the total mols of the optionally protected primary amino group possessed by the conjugated diene based (co)polymer, to obtain the modified conjugated diene based (co)polymer.

8. The method for producing a modified conjugated diene based (co)polymer, set forth in claim 1 , wherein the reaction is conducted by adding water.

9. A modified conjugated diene based (co)polymer obtained by the method for producing a modified conjugated diene based (co)polymer, set forth in claim 1 .

10. A rubber composition comprising, as the rubber component, the modified conjugated diene based (co)polymer set forth in claim 9 .

11. The rubber composition set forth in claim 10 , further comprising at least either of silica and carbon black.

12. The rubber composition set forth in claim 11 , which comprises a rubber component containing 20 mass % or more of the modified conjugated diene based (co)polymer and at least either of silica and carbon black wherein the at least either of silica and carbon black is contained in an amount of 20 to 120 parts by mass relative to 100 parts by mass of the rubber component.

13. The rubber composition set forth in claim 10 , wherein the rubber component comprises the modified conjugated diene based (co)polymer and another rubber component, wherein the content of the modified conjugated diene based (co)polymer is 20 to 100 mass % and the content of the other rubber component is 0 to 80 mass % provided the modified conjugated diene based (co)polymer+the other rubber component=100 mass %, and the other rubber component is at least one kind of rubber component selected from the group consisting of natural rubber, synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-α-olefin copolymer rubber, ethylene-α-olefin-diene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber and halogenated butyl rubber.