According to an embodiment of the present invention, there is provided a method of preparing a rubber composition, which includes (a) synthesizing a living polymer by solution polymerization of a monomer mixture including a conjugated diene-based monomer in the presence of a first catalyst; (b) reacting some ends of the living polymer with a coupling agent; (c) reacting the remaining ends of the living polymer with an organotin halide compound to prepare an end-modified conjugated diene-based polymer solution; and (d) adding a second catalyst and a conjugated diene-based monomer to the end-modified conjugated diene-based polymer solution to induce solution polymerization.

The present invention relates to a method of preparing a modified conjugated diene-based polymer, and more particularly, to a method of preparing a modified conjugated diene-based polymer, including: (S1) preparing an active polymer with an organic metal bonded thereto by polymerizing a conjugated diene-based monomer in a hydrocarbon solvent in the presence of an organometallic compound; and (S2) mixing the active polymer prepared according to process S1 with a modifier, wherein the mixing of process S2 is performed at a Reynolds number of 20 or less for 1 minute or more, the Reynolds number being maintained within a range of 5 of a Reynolds number when the modifier is added (wherein the range is between greater than 0 to 20 or less).

The present invention relates to a method of preparing a modified conjugated diene-based polymer, and more particularly, to a method of preparing a modified conjugated diene-based polymer, including: (S1) preparing an active polymer with an organic metal bonded thereto by polymerizing a conjugated diene-based monomer in a hydrocarbon solvent in the presence of an organometallic compound; and (S2) mixing the active polymer prepared according to process S1 with a modifier, wherein the mixing of process S2 is performed at a Reynolds number of 20 or less for 1 minute or more, the Reynolds number being maintained within a range of 5 of a Reynolds number when the modifier is added (wherein the range is between greater than 0 to 20 or less).

The invention relates to a method for producing a modified conjugated diene-based polymer, comprising a step of reacting an organometallic compound with a unit based on a modifying agent, in a conjugated diene-based polymer that has a unit based on a conjugated diene compound-containing monomer and a unit based on a modifying agent having a silicon atom, tin atom, germanium atom or phosphorus atom.

The invention relates to a method for producing a modified conjugated diene-based polymer, comprising a step of reacting an organometallic compound with a unit based on a modifying agent, in a conjugated diene-based polymer that has a unit based on a conjugated diene compound-containing monomer and a unit based on a modifying agent having a silicon atom, tin atom, germanium atom or phosphorus atom.

The present invention relates to a method for the preparation of a synthetic rubber blend, wherein the blend comprises a high molecular weight diene polymer (A) having a number average molecular weight (Mn) of from 50.000 to 1.000.000 g/mol with a high trans content as well as a low molecular weight diene polymer (B) having a number average molecular weight (Mn) of from 250 to 10.000 g/mol. The present invention further relates to synthetic rubber blends that are obtainable according to the method described herein; as well as to rubber compositions comprising the blend and articles such as tires.

The diimide hydrogenation of unsaturated elastomers in latex utilizing hydrazine and hydrogen peroxide or oxygen, is a metal-catalyzed process. Copper ion has been found to be the most superior catalyst for this reaction, requiring an extremely low concentration for optimal results. Generated diimide efficiently hydrogenates the polymer olefinic unsaturation while generating water and nitrogen as byproducts. With a falling hydrazine concentration during the hydrogenation process however, a competing copper-catalyzed process capable of generating hydroxyl, superoxide and/or copper-oxyl radicals becomes increasingly competitive. The ability of these radical species to abstract hydrogen from the polymer backbone to generate polymeric radicals, ultimately results in crosslinking that occurs concurrently with hydrogenation. The concept of an OH radical inactivating ligand (OIL) complexed with copper is demonstrated to ameliorate the crosslinking reaction.

The diimide hydrogenation of unsaturated elastomers in latex utilizing hydrazine and hydrogen peroxide or oxygen, is a metal-catalyzed process. Copper ion has been found to be the most superior catalyst for this reaction, requiring an extremely low concentration for optimal results. Generated diimide efficiently hydrogenates the polymer olefinic unsaturation while generating water and nitrogen as byproducts. With a falling hydrazine concentration during the hydrogenation process however, a competing copper-catalyzed process capable of generating hydroxyl, superoxide and/or copper-oxyl radicals becomes increasingly competitive. The ability of these radical species to abstract hydrogen from the polymer backbone to generate polymeric radicals, ultimately results in crosslinking that occurs concurrently with hydrogenation. The concept of an OH radical inactivating ligand (OIL) complexed with copper is demonstrated to ameliorate the crosslinking reaction.

A method for producing a hydrogenated polymer composition including a hydrogenated conjugated diene modified polymer that has a boron-containing functional group, the method including: (1) anionically polymerizing a monomer including a conjugated diene in the presence of a reactive metal or reactive metal compound capable of causing anionic polymerization to produce a reactive terminal polymer (Z); (2) reacting the reactive terminal polymer (Z) obtained in (1) with a boric acid compound that has at least two partial structures represented by BOR (I), and in which at least one R bonded to an oxygen atom in the partial structure (I) has a Taft's steric parameter Es value of ?0.30 or less to obtain an unhydrogenated conjugated diene modified polymer having a boron-containing functional group; and (3) hydrogenating at least some of carbon-carbon double bonds contained in conjugated diene units included in the unhydrogenated conjugated diene modified polymer obtained in (2).

A method for producing a hydrogenated polymer composition including a hydrogenated conjugated diene modified polymer that has a boron-containing functional group, the method including: (1) anionically polymerizing a monomer including a conjugated diene in the presence of a reactive metal or reactive metal compound capable of causing anionic polymerization to produce a reactive terminal polymer (Z); (2) reacting the reactive terminal polymer (Z) obtained in (1) with a boric acid compound that has at least two partial structures represented by BOR (I), and in which at least one R bonded to an oxygen atom in the partial structure (I) has a Taft's steric parameter Es value of ?0.30 or less to obtain an unhydrogenated conjugated diene modified polymer having a boron-containing functional group; and (3) hydrogenating at least some of carbon-carbon double bonds contained in conjugated diene units included in the unhydrogenated conjugated diene modified polymer obtained in (2).