Abstract: A modified conjugated diene polymer comprises a modifying group based on a low molecular weight compound having two or more tertiary amino groups and one or more alkoxysilyl groups in a molecule which bonds to a conjugated diene polymer obtained by polymerization of a conjugated diene compound or a conjugated diene polymer obtained by copolymerization of a conjugated diene compound and an aromatic vinyl compound. The process for producing the modified conjugated diene polymer comprises the steps of: polymerizing a conjugated diene compound or copolymerizing a conjugated diene compound and an aromatic vinyl compound in a hydrocarbon solvent using an alkali metal initiator and/or an alkaline earth metal initiator; and reacting active terminals of the resulting polymer with a low molecular weight compound having two or more tertiary amino groups and one or more alkoxysilyl groups in the molecule.

Abstract: A process for producing a conjugated diene polymer composition, which comprises of polymerizing a conjugated diene compound or a conjugated diene compound and an aromatic vinyl compound in a hydrocarbon solvent in the presence of at least one compound selected from the group consisting of organoalkali metals and organoalkaline earth metals as an initiator and then reacting the active end of the resulting polymer with a low molecular compound represented by the following formula (1) or the following formula (2): wherein the variables R through R9 are as defined in the Specification.

Abstract: A modified conjugated diene polymer comprises a modifying group based on a low molecular weight compound having two or more tertiary amino groups and one or more alkoxysilyl groups in a molecule which bonds to a conjugated diene polymer obtained by polymerization of a conjugated diene compound or a conjugated diene polymer obtained by copolymerization of a conjugated diene compound and an aromatic vinyl compound. The process for producing the modified conjugated diene polymer comprises the steps of: polymerizing a conjugated diene compound or copolymerizing a conjugated diene compound and an aromatic vinyl compound in a hydrocarbon solvent using an alkali metal initiator and/or an alkaline earth metal initiator; and reacting active terminals of the resulting polymer with a low molecular weight compound having two or more tertiary amino groups and one or more alkoxysilyl groups in the molecule.

Abstract: A process for producing a conjugated diene polymer composition, which comprises of polymerizing a conjugated diene compound or a conjugated diene compound and an aromatic vinyl compound in a hydrocarbon solvent in the presence of at least one compound selected from the group consisting of organoalkali metals and organoalkaline earth metals as an initiator and then reacting the active end of the resulting polymer with a low molecular compound represented by the following formula (1) or the following formula (2): (wherein in the formula (1), R1 represents an organic group containing an N atom not adjacent to the N atom of the aminosilyl group and having a molecular weight not greater than 1000, R2 represents a C1-10 hydrocarbon group or a C1-10 hydrocarbon group having no active hydrogen and substituted with an Si, O, N or S atom, R3 and R4 each independently represents a C1-20 alkyl group or aryl group, R5, R6, and R7 each represents a C1-20 alkyl group or aryl group or a C1-12 alkoxy group and g stands fo