JP2016050257A - Method for producing deformed solution -polymerized diene rubber for silica blending and rubber composition thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a terminal deformed solution-polymerized diene rubber for silica blending having storage stability and having physical properties such as impact resilience, and a rubber composition.SOLUTION: Provide is a method for producing a deformed solution-polymerized diene rubber stable in productivity and also excellent in storage stability where, at first, small quantities of monomers high in vulcanization velocity are suitably polymerized in the coexistence of an organic lithium compound or a secondary amine compound, successively, the other conjugated diene compound and aromatic vinyl compound are polymerized in hydrocarbon, after the completion of the polymerization, a specified tin compound and a specified silane compound are successively added, coupling efficiencies are controlled respectively at specified ratios, thereafter, a metal halide compound is further added under no presence of active diene rubber under specified conditions, next, the coupling efficiencies are increased by stream solidification.SELECTED DRAWING: None

Description

  The present invention relates to a method and a rubber composition for producing a terminal-modified solution-polymerized diene rubber for compounding silica having physical properties such as storage stability and excellent impact resilience. The terminal-modified solution-polymerized diene rubber obtained by this production method has high strength and impact resilience, and when used for a tire rubber, it is optimal for an automobile tire having good processability and excellent fuel efficiency.

Silica-containing rubber compositions are effective for low fuel consumption tires. A solution-polymerized diene rubber modified with an alkoxysilane compound that efficiently disperses silica is effective in improving the resilience or viscoelasticity test tan δ, which is a laboratory indicator of low fuel consumption. However, the Si-OR group contained in this modified solution polymerized diene rubber is hydrolyzed with moisture such as in the air, and further causes a condensation reaction, so that the molecular weight increases during storage, and silica essential for improving physical properties There has been a problem in that the reactivity of the is lowered.
On the other hand, in order to improve the resilience and the like, it is necessary to introduce a functional group that reacts with silica such as an alkoxysilyl group at one end in terms of the molecular design of the rubber. So far, the other end, that is, the terminal end modified diene rubber, which has a structure that easily reacts with silica, is considered to be combined with silica to suppress molecular motion and improve fuel efficiency. . However, as a matter of fact, it has been found that when functional groups having high reactivity with silica such as alkoxysilyl groups are introduced at both ends, the agglomerated silica cannot be efficiently dispersed when kneaded with silica.
Therefore, the functional group at one end that does not contain an alkoxysilyl group has a relatively low interaction between silica and rubber when kneaded, and is considered to have an excellent structure that is easily crosslinked with silica or other molecules during the vulcanization reaction. However, many problems still remain in the process of producing a silica-modified modified solution-polymerized diene rubber with stable quality and good industrial productivity.

  As shown in Patent Document 1 and Patent Document 2, the inventors made a reaction by reacting an alkoxysilane compound having a large steric hindrance that hardly causes hydrolysis after polymerization of styrene and butadiene using alkyllithium as a polymerization initiator. For the first time, a method for producing a modified solution polymerized diene rubber for blending silica having an alkoxysilyl group was disclosed, and industrial production was started. However, it was later found that alkoxysilane compounds do not have polar groups containing N atoms and the like, and diene rubbers modified with this compound have a slightly low reactivity with silica.

  Patent Document 3 discloses a modified SBR produced by reacting an aminoalkoxysilane compound after polymerizing styrene and butadiene using alkyllithium as a polymerization initiator, and discloses the evaluation result of blending with carbon black alone. .

  Patent Document 4 discloses SBR for silica blending with good storage stability by reacting an aminoalkoxysilane compound similar to Patent Document 3 at a specific ratio after polymerization of styrene and butadiene using alkyllithium as a polymerization initiator. Is disclosed.

  Patent Document 5 discloses a property evaluation result only by blending carbon black by synthesizing coupling SBR by adding tin tetrachloride after polymerizing styrene and butadiene using lithium morpholinide as a polymerization initiator. ing.

  In Patent Document 6, the inventors do not mix with silica, but alkyllithium containing an amino group or the like is used as a polymerization initiator, and after block copolymerization of styrene and butadiene, an aminoalkoxysilane compound is reacted, and a butadiene moiety A process for producing a hydrogenated polymer is disclosed.

  In Patent Document 7 and Patent Document 8, physical property evaluation results of a silica compound of a polymer obtained by reacting an aminoalkoxysilane compound after polymerization of styrene and butadiene as a post-reaction initiator by adding a small amount of monomer to aminoalkyl lithium Is disclosed. However, the polymerization initiator has a special structure, and the synthesis is industrially complicated and difficult to produce stably.

In Patent Document 9, after polymerization of styrene and butadiene using alkyllithium as a polymerization initiator and before reaction with an aminoalkoxysilane compound, coupling was performed with an equivalent tin halide compound equivalent to half of the alkyllithium used. SBR for blending carbon black is disclosed.
However, in recent years, there has been an increasing demand for improvement in fuel efficiency of automobiles due to prevention of global warming and energy problems. Silica-blended tires have improved fuel efficiency compared to carbon black-blown tires, but alkoxysilane-modified solution polymerized diene rubbers suitable for silica blends have a problem of changing Mooney viscosity (MV) during storage, In addition, there is an increasing demand for further improvement in fuel efficiency.

Japanese Patent Publication No. 6-51746 Japanese Examined Patent Publication No. 7-68307 Japanese Patent Publication No. 6-53768 JP 2013-53293 A Japanese Examined Patent Publication No.59-38209 Japanese Patent No. 3988495 Japanese Patent No. 4289111 Japanese Patent No. 4655706 Japanese Patent No. 2625876

  In such a situation, the problem to be solved by the present invention is an end-modified solution polymerized diene rubber having excellent rebound resilience, good steam removal, excellent storage stability and processability during compounding, and It is to provide the rubber composition.

  As a result of intensive studies on a method for producing a conjugated diene rubber having high rebound resilience and excellent storage stability, the inventors of the present invention have a fast initial vulcanization rate in the presence of an organic lithium compound or a secondary amine compound as appropriate. After polymerizing the monomer in a small amount, the other conjugated diene compound and aromatic vinyl compound are subsequently polymerized in hydrocarbon, and after completion of the polymerization, a specific tin compound and a specific silane compound are added in order to determine the coupling efficiency. After controlling at a ratio, by adding a metal halide compound under specific conditions in the absence of active diene rubber, and then increasing the coupling efficiency by steam coagulation, the productivity is stable and the storage stability is improved. In addition, the present inventors have developed a method for producing a modified solution polymerization diene rubber excellent in the present invention and completed the present invention.

That is, the first invention of the present invention is: i) polymerization of a conjugated diene compound and an aromatic vinyl compound in a hydrocarbon in the presence of an organic lithium compound or a secondary amine compound,
ii) After completion of the polymerization, a tin compound represented by the formula (1) is added, and the diene rubber is treated so that the components of 3 or more branches are 5 to 30%,
iii) Subsequently, a silane compound represented by the formula (2) is added and treated so that the bi-branched component of the diene rubber is 30% or less,
iv) The obtained polymer composition is steam-coagulated and dried to increase the content of two or more branches by 10 to 50% with respect to the state before steam coagulation, and the Mooney viscosity (a ) Is further heat-stabilized to such an extent that the Mooney viscosity (b) fluctuates by not more than 10 when heat-treated for 20 minutes in a subsequent roll mill at 130 ° C., a method for producing a modified solution-polymerized diene rubber.
Here, R ¹ is an alkyl group having 1 to 12 carbon atoms, an aromatic group, or an allyl group, X is a halogen compound of iodine, bromine, or chlorine, n is an integer, 0 or 1 It is.
Here, R ² is an alkyl group having 1 to 12 carbon atoms, an aromatic group, an allyl group, or an alkyl group, an aromatic group or an allyl group containing a nitrogen atom in these functional groups, and R ³ is carbon. An alkyl group or an aromatic group having 1 to 12 atoms, an allyl group, or an alkyl group or an aromatic group or an allyl group containing an oxygen atom and / or a nitrogen atom in these functional groups, m is an integer, 4.

The second invention of the present invention relates to several more optimal methods for producing the modified solution polymerized diene rubber.
After the above iii) step, before the iv) step, the metal halide compound represented by the formula (3) in an amount satisfying the formula (4) is added, and then the iv) the steam coagulation / drying in the step A method for producing a solution-polymerized diene rubber.
Here, M is a tin atom or a silicon atom, R ⁴ is an alkyl group having 1 to 12 carbon atoms, an aromatic group, an allyl group, or a carboxyl group, and X is any one of iodine, bromine, and chlorine Halogen compound, p is an integer and is 0 or 1.
Here, L is the number of moles of the organolithium compound added at the start of polymerization, A is the number of moles of the tin compound of the formula (1) added, and B is the metal halide compound shown by the added formula (3) N and p are integers represented by formula (1) and formula (3), respectively.

  The third invention of the present invention relates to a rubber composition for silica compounding containing the above modified solution polymerized diene rubber in a total rubber component of 20 phr or more.

  The present invention relates to a process for producing a modified solution polymerized diene rubber for compounding silica having excellent solvent removal, excellent storage stability, good workability, and excellent physical properties such as strength and impact resilience, and its rubber composition. It is about.

Examples of the conjugated diene compound used in the present invention include 1,3-butadiene, isoprene, 1,3-pentadiene (piperine), 2,3-dimethyl-1,3-butadiene, 1,3-hexadiene, and the like. Can do. Among these, 1,3-butadiene and isoprene are preferable from the viewpoint of easy availability and physical properties of the resulting modified solution polymerization diene rubber. 1,3-butadiene is particularly preferable.
The amount of the conjugated diene compound used is usually 40 to 100% by weight, preferably 50 to 95% by weight, based on all monomers. If it is less than 40% by weight, the hysteresis loss increases.

Examples of the aromatic vinyl compound used in the present invention include styrene, α-methylstyrene, vinyl toluene, vinyl naphthalene, divinyl benzene, trivinyl benzene, and divinyl naphthalene. Among these, styrene is preferable from the viewpoint of availability and physical properties of the resulting modified solution polymerization diene rubber.
The amount of the aromatic vinyl compound used is usually 60% by weight or less, preferably 50 to 5% by weight, based on all monomers.

  The organic lithium compound used in the present invention is a lithium compound having 2 to 20 carbon atoms. For example, ethyl lithium, n-propyl lithium, iso-propyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, tert-octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, 2- Butyl-phenyl lithium, 4-phenyl-butyl lithium, cyclohexyl lithium, 4-cyclopentyl lithium, 1,4-dilithio-butene-2, and the like. Preferably, n-butyllithium, sec-butyllithium and tert-butyllithium are preferable from the viewpoint of industrial availability and stability, and n-butyllithium and sec-butyllithium are particularly preferable.

The secondary amine compound used in the present invention is a compound represented by formula (4) or formula (5).
Here, R ⁵ and R ⁶ are an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group or an aralkyl group, R ⁵ and R ⁶ may be the same or different, and R ⁷ is 3 to 3 It is a divalent alkylene, bicycloalkane, oxy- or amino-alkylene group having 12 methylene groups.

Examples of R ⁵ and R ⁶ in the formula (5) include methyl, ethyl, butyl, hexyl, octyl, cyclohexyl, 3-phenyl-1-propyl, isobutyl and the like. Specific examples include methylethylamine, diethylamine, dibutylamine, ethylbutylamine, dihexylamine, dioctylamine, butyloctylamine, octylcyclohexylamine, diisobutylamine, and butyl (3-phenyl-1-propyl) amine. Preferred are dioctylamine and dihexylamine, which have good industrial availability and solubility in hydrocarbon solvents.

R ⁷ groups of formula (6) include, for example, trimethylene, tetramethylene, hexamethylene, oxydiethylene, N-alkylazadiethylene, and the like. Specific examples include pyrrolidine, piperidine, hexamethyleneimine or heptamethyleneimine. Moreover, bicyclic bodies such as decahydroisoquinoline and perhydroindole may be used. Particularly preferred are pyrrolidine, piperidine, hexamethyleneimine or heptamethyleneimine.

  Examples of the compound that is prepolymerized in the coexistence of the organic lithium compound and the secondary amine compound include compounds having a vulcanization rate faster than that of butadiene. Specifically, isoprene, 1,3-pentadiene (piperine), 2,3- Dimethyl-1,3-butadiene. Isoprene is preferred from the standpoint of industrial availability and vulcanization speed.

Specific examples of the tin compound represented by the formula (1) include the following compounds.
For example, tin tetrachloride, ethyl tin trichloride, propyl tin chloride, butyl tin chloride, octyl tin trichloride, cyclohexyl tin trichloride, tin tetrabromide, ethyl tribromide, propyl tribromide, butyl trichloride Tin bromide, octyl tin tribromide, cyclohexyl tin bromide, tin tetraiodide, tin triiodide iodide, tin propyl triiodide, tin butyl triiodide, tin octyl triiodide, tin cyclohexyl triiodide Can be mentioned. Among these, tin tetrachloride, octyl tin trichloride, and tin tetrabromide are preferable. Particularly preferred is tin tetrachloride.

Specific examples of the silane compound represented by the formula (2) include the following compounds.
For example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, tetraphenoxysilane, tetratoluoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, methyltriphenoxysilane , Ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltributoxysilane, ethyltriphenoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldipropoxysilane, dimethyldibutoxysilane, dimethyldiphenoxysilane, Diethyldimethoxysilane, diethyldiethoxysilane, diethyldipropoxysilane, diethyldibutoxysilane, diethyldiph Noxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltributoxysilane, vinyltriphenoxysilane, vinyltri (2-methoxyethoxy) silane, vinyltri (methylethylketoxime) silane, methyltri (methylethylketoxime) silane, Methyltris (diethylketoxime) silane, ethyltri (methylethylketoxime) silane, ethyltris (dimethylketoxime) silane, allyltriphenoxysilane, octenyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltripropoxysilane, phenyl Tributoxysilane, phenyltriphenoxysilane, 2- (3,4-epoxycyclohexyl) ethylto Methoxysilane, vinyltri (methoxypropoxy) silane, methyltris [2- (dimethylamino) ethoxy] silane, methyltris [2- (diethylamino) ethoxy] silane, methyltris [2- (dibutylamino) ethoxy] silane, ethyltris [2- ( Dimethylamino) ethoxy] silane, ethyltris [2- (diethylamino) ethoxy] silane, ethyltris [2- (dibutylamino) ethoxy] silane, tetrakis [2- (dimethylamino) ethoxy] silane, tetrakis [2- (diethylamino) ethoxy And silane and tetrakis [2- (dibutylamino) ethoxy] silane. Among these, preferred are ketoxime silanes and trimethoxylanes, triethoxysilanes, tripropoxysilanes, or modified solution polymerized diene rubbers which are relatively easily hydrolyzed while increasing the storage stability. These are aminoethoxysilanes that are presumed to promote reactivity with silica.

  Specific examples of the aminoalkoxysilane compound are shown below. Dimethylaminomethyltrimethoxysilane, 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 4-dimethylaminobutyltrimethoxysilane, dimethylaminomethyldimethoxymethylsilane, 2-dimethylaminoethyldimethoxymethylsilane, 3-dimethylaminopropyldimethoxymethylsilane, 4-dimethylaminobutyldimethoxymethylsilane, dimethylaminomethyltriethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 3-diethylaminopropyltrimethoxysilane 4-dimethylaminobutyltriethoxysilane, dimethylaminomethyldiethoxymethylsilane, 2-dimethylaminoethyldiethoxymethyl Silane, 3-dimethylaminopropyldiethoxymethylsilane, 4-dimethylaminobutyldiethoxymethylsilane, N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole, N-allyl-aza-2,2- Examples thereof include dimethoxysila-cyclopentane, and 3-dimethylaminopropyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, and 3-diethylaminopropyltrimethoxysilane are particularly preferable.

  Examples of alkoxysilane compounds having a protecting group that becomes a primary amino group after hydrolysis include N, N-bis (trimethylsilyl) -3-aminopropyltrimethoxysilane, N, N-bis (trimethylsilyl) -3-aminopropyltri Ethoxysilane, N, N-bis (trimethylsilyl) -3-aminopropyltripropoxysilane, N, N-bis (trimethylsilyl) -2-aminoethyltrimethoxysilane, N, N-bis (trimethylsilyl) -2-aminoethyl Methyldimethoxysilane and N, N-bis (trimethylsilyl) aminoethylmethyldiethoxysilane, 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane, N, N-diethyl-3-aminopropyltri Methoxysilane, N, N-diethyl-3 -Aminopropyltriethoxysilane, 2- (triethoxysilylethyl) pyridine, γ-isocyanatopropyltriethoxysilane and the like can be mentioned.

Specific examples of the metal halide compound represented by the formula (3) include the following compounds.
For example, tin tetrachloride, ethyl tin trichloride, propyl tin trichloride, butyl tin chloride, octyl tin chloride, cyclohexyl tin chloride, tin tetrabromide, ethyl triodor, which are tin compounds represented by the formula (1) Tin iodide, propyl tin tribromide, butyl tin bromide, octyl tin tribromide, cyclohexyl tin tribromide, tin tetraiodide, tin triiodide iodide, tin propyl triiodide, tin butyl triiodide, Mention may be made of octyl tin triiodide and cyclohexyl triiodide.
Silicon compounds such as silicon tetrachloride, methyl silicon trichloride, ethyl silicon trichloride, propyl silicon trichloride, butyl silicon trichloride, octyl silicon trichloride, cyclohexyl silicon trichloride, silicon tetrabromide, methyl silicon tribromide, ethyl Silicon tribromide, propyl silicon tribromide, butyl silicon tribromide, octyl silicon tribromide, cyclohexyl silicon tribromide, silicon tetraiodide, silicon silicon triiodide, propyl silicon triiodide, butyl triiodide Examples include silicon, octyl silicon triiodide, and cyclohexyl silicon triiodide.
Of these, preferred are silicon tetrachloride, methyl silicon trichloride, ethyl silicon trichloride, tin tetrachloride, and octyl tin trichloride. Particularly preferred are silicon tetrachloride and methyl silicon trichloride.

  The usage conditions such as the amount of raw materials used to produce the solution-polymerized diene rubber, the reaction temperature and the reaction time are as follows.

The solution polymerization reaction of the diene rubber is performed by a commonly used method. The conjugated diene compound or the aromatic vinyl compound is heated at 10 to 120 ° C. in the presence of an organic lithium compound and a polar compound such as an ether compound or an amine compound. Polymerization is carried out at a temperature of several tens of minutes to several hours.
The amount of the organic lithium compound used is usually in the range of 0.1 to 10 mmol per 100 g of diene rubber. If the molecular weight is less than 0.1 mmol, the molecular weight becomes too high and the solution viscosity increases and the MV viscosity becomes high, which causes problems in rubber production processes and tire manufacturing processes. On the other hand, if it exceeds 10 mmol, the molecular weight of the diene rubber becomes too low, and the vulcanized physical properties are greatly lowered.

For the polymerization, as ether compounds for adjusting the microstructure of the diene monomer portion of the diene rubber, particularly vinyl content, diethyl ether, di-n-butyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, propylene Glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether, tetrahydrofuran (THF), 2,2-di (2-tetrahydrofuryl) propane (DTHP), bistetrahydrofurfuryl formal, methyl ether of tetrahydrofurfuryl alcohol, tetrahydrofur Ethyl ether of furyl alcohol, butyl ether of tetrahydrofurfuryl alcohol, α-methoxy Rahidorofuran, dimethoxybenzene, and dimethoxyethane are used.
As an amine compound, triethylamine, pyridine, N, N, N ′, N′-tetramethylethylenediamine, dipiperidinoethane, methyl ether of N, N-diethylethanolamine, ethyl ether of N, N-diethylethanolamine, A tertiary amine compound such as butyl ether of N, N-diethylethanolamine is used.
Preferred compounds include tetrahydrofuran (THF) and 2,2-di (2-tetrahydrofuryl) propane (DTHP) in view of polymerization rate and modification efficiency.
The addition amount of these compounds is usually 0.01 to 10 mol, preferably 0.2 to 5 mol with respect to 1 mol of the organic lithium compound when a plurality of N atoms, O atoms and the like are included. It is preferable to add 0.05 to 10% of a compound having one O atom in the molecule such as tetrahydrofuran with respect to the solvent.

  The polymerization reaction is performed in a hydrocarbon solvent. Suitable hydrocarbon solvents are selected from aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, especially propane, n-butane, iso-butane, n-pentane having 3 to 12 carbon atoms, iso-pentane, n-hexane, cyclohexane, n-heptane, propene, 1-butene, iso-butene, trans-2-butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2- Hexene, benzene, toluene, xylene, ethylbenzene and the like. Preferred are n-pentane, iso-pentane, n-hexane, cyclohexane and n-heptane. These solvents can be used as a mixture of two or more.

  In the present invention, a conjugated diene compound or a conjugated diene compound and an aromatic vinyl compound are anionically polymerized, the active diene rubber is coupled with a tin compound, and then a silane compound is reacted. These modification reactions are usually 0 to 120 ° C., preferably 50 to 100 ° C., and the reaction time is 1 to 30 minutes, preferably 5 to 20 minutes.

  The polymerization mode used in the present invention can be a batch polymerization method or a continuous polymerization method. The batch polymerization method is suitable for the modified solution polymerized diene rubber characterized by rebound resilience, and the continuous polymerization method is suitable for the modified solution polymerized diene rubber characterized by wear resistance and processability.

In step ii), the tin compound represented by the formula (1) is added to the active diene rubber before modification to first produce a diene rubber coupled with a tri- or higher functional tin compound. The proportion of three or more branches of this diene rubber is preferably 5 to 30%. If it is less than 5%, the reactivity with carbon black usually used in combination with silica is lowered, and crumbs (a mass of undried rubber of several millimeters to several centimeters) are fused to each other in the steam demelting and drying process. It becomes difficult to dry. If it exceeds 30%, the component that reacts with silica decreases, and the rubber vulcanized physical properties of silica compound are lowered. Therefore, the more preferable proportion of the three-branched component of the diene rubber is 10 to 25%.
Specifically, in the case of tin tetrachloride, it is 0.0125 to 0.075 mol equivalent to the active diene rubber. More preferably, it is 0.0125-0.05 mol equivalent.
The ratio of these branched structures can be measured by GPC.

In step iii), a silane compound represented by the formula (2) is added to produce a diene rubber so that the bifurcated structure is 30% or less. The addition amount of the silane compound is preferably an amount corresponding to 0.8 to 2 times the number of molecules per active diene rubber remaining in the step ii), more preferably 1.0 to 1. 5 times. When it is less than 0.8, the number of alkoxysilyl groups introduced into the active diene rubber is reduced and the reactivity with silica is lowered. If it is twice or more, the storage stability is deteriorated.
However, the modified solution polymerized diene rubber having a structure in which one molecule of silane compound is bonded to the diene rubber is very unstable and causes a problem that the Mooney viscosity increases during storage. Therefore, in order to convert into a structure that is stable during storage and reacts with silica when blended with rubber, drying is performed so that the components of two or more branches after steam coagulation increase by 10 to 50%.

According to the present invention, the branched structure after steam coagulation / drying is the following two-branched structure-A, which is stable when storing rubber and is highly reactive with silica when compounded with silica. ing. In addition, it is presumed that the bifurcated structure-A is formed by condensation of (Rubber) -Si-OH in which (Rubber) -Si-OR modified with the silane compound of formula (2) is hydrolyzed. . In the conventional bifurcated structure-B, the reactivity with silica is low. Therefore, it is preferable to increase the proportion of the bifurcated structure-A, and this proportion is preferably 10 to 50%. If it is less than 10%, the Mooney viscosity stability during storage is poor, and a production method exceeding 50% is not economical because the production conditions are narrow and the productivity is poor. A more desirable ratio is 20% to 40%.
Bifurcated structure A (structure of the present invention): (Rubber) -Si-O-Si- (Rubber)
Bifurcated structure B (conventional structure): (Rubber) -Si- (Rubber)
The proportion of these branched structures is determined by GPC in the manufacturing process.

In the present invention, in order to further improve the drying process and the storage stability, first, after coupling the active diene rubber with the tin compound represented by the formula (1) in the step ii), the formula (2) is followed by the step iii). The silane compound shown is reacted with the active diene rubber under the conditions where the number of components of the bifurcated structure is as small as possible. Furthermore, before the steam coagulation / drying in the step iv), the metal halide compound shown by the formula (3) is added You may do it. This metal halide compound is added under conditions satisfying the formula (4), and is deactivated by impurities contained in the solvent or monomer, or neutralizes the lithium compound by-produced by the reaction between the active diene rubber and the silane compound. Because.
The addition amount of the metal halide compound is preferably L- (4-n) A ≦ (4-p) B ≦ 2L. More preferably, L− (4-n) A ≦ (4-p) B ≦ 1.5L.
In the case of L- (4-n) A> (4-p) B, neutralization is insufficient and the workability and the storage stability of the modified solution polymerized diene rubber during steam coagulation are deteriorated. When (4-p) B> 2L, the acidity of the rubber becomes too strong and the storage stability deteriorates, causing problems such as metal corrosion.

The weight average molecular weight of the modified solution polymerization diene rubber obtained in the present invention is 100,000 to 1,000,000, preferably 150,000 to 700,000 in terms of polystyrene. If it is less than 100,000, the strength, abrasion resistance, impact resilience, etc. of the resulting rubber composition are not sufficient, while if it exceeds 1,000,000, the processability is inferior, and the filler dispersibility during kneading deteriorates, Strength, abrasion resistance, impact resilience, etc. deteriorate.
The Mooney viscosity (abbreviated as MV, ML _{1 +} 4/100 _{° C.} when expressing measurement conditions) of the modified solution polymerized diene rubber obtained in the present invention is preferably in the range of 20 to 150, 20 If it is less than 150, the strength, wear resistance, and impact resilience are deteriorated.

  The vinyl content of the diene portion of the modified solution polymerized diene rubber in the present invention is generally changed in the range of 20 to 80%. Considering the vulcanized physical properties of the diene rubber, it is preferable to change it by 30 to 70%. If the wear resistance is important, the vinyl content should be low, and if the brake performance on wet roads is important, the vinyl content should be high.

Extending oil can be added to the polymerization reaction solution containing the modified solution polymerization diene rubber of the present invention. As the extending oil, those usually used in the rubber industry can be used, and examples thereof include paraffinic extending oil, aromatic extending oil, and naphthenic extending oil.
The pour point of the extending oil is preferably -20 to 50 ° C, more preferably -10 to 30 ° C. If it is this range, it will be easy to extend and the rubber composition excellent in the balance of a tensile characteristic and low exothermic property will be obtained. The suitable aroma carbon content (CA%, Kurz analysis method) of the extender oil is preferably 20% or more, more preferably 25% or more, and the suitable paraffin carbon content (CP%) of the extender oil is , Preferably 55% or less, more preferably 45%. If CA% is too small or CP% is too large, tensile properties will be insufficient. The content of the polycyclic aromatic compound in the extending oil is preferably less than 3%. This content is measured by the IP346 method (the testing method of The Institute Petroleum, UK).
The content of the extending oil is preferably 1 to 50 parts by weight, more preferably 5 to 30 parts by weight with respect to 100 parts by weight of the rubber composition. When the content of the extending oil is within this range, the viscosity of the rubber composition containing silica becomes appropriate, and the balance between tensile properties and low exothermic properties is excellent.

  When the modified solution polymerized diene rubber of the present invention is used as a rubber composition for tires, natural rubber, isoprene rubber, butadiene rubber, emulsion-polymerized styrene butadiene rubber, etc., as long as the effects of the present invention are not essentially impaired. After blending, kneading with a reinforcing agent such as silica and / or carbon black and various compounding agents with a roll mill or Banbury mixer, sulfur, vulcanization accelerator, etc. are added, and tires such as treads, sidewalls, carcass, etc. Rubber can be used. These compositions can also be used in belts, anti-vibration rubber and other industrial products.

  As a reinforcing material to be filled when the modified solution-polymerized diene rubber of the present invention is used for a tire, particularly a tire tread, a filler having a hydroxyl group on the surface, such as silica, is optimal. Further, carbon black can be used in combination. The filling amount of the filler is preferably 20 to 150 phr, more preferably 30 to 100 phr with respect to 100 phr of all rubber components.

Examples of silica include dry silica, wet silica, colloidal silica, and precipitated silica. Among these, wet silica containing hydrous silicic acid as a main component is particularly preferable. These silicas can be used alone or in combination of two or more.
The particle size of primary particles of silica is not particularly limited, but is 1 to 200 nm, more preferably 3 to 100 nm, and particularly preferably 5 to 60 nm. When the particle size of the primary particles of silica is within this range, the balance between tensile properties and low heat build-up is excellent. The particle size of the primary particles can be measured with an electron microscope, a specific surface area, or the like.

In the rubber composition of the present invention, a silane coupling agent is preferably compounded at the time of rubber compounding for the purpose of further improving the tensile properties and low heat build-up. Examples of the silane coupling agent include β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, and bis (3-triethoxysilylpropyl). Tetrasulfide, bis (3-tri-iso-propoxysilylpropyl) tetrasulfide, bis (3-tributoxysilylpropyl) tetrasulfide, γ-trimethoxysilylpropyldimethylthiocarbamyl tetrasulfide, γ-trimethoxysilylpropylbenzo Tetrasulfides such as thiazyl tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-tri-iso-propoxysilylpropyl) disulfide, bis (3-tributoxysilylpropyl) disulfide, γ-trimethoxysilylpropyldimethylthiocarbamyl disulfide, γ-trimethoxysilylpropylbenzothiazyl disulfide and the like can be mentioned.
Since a scorch at the time of kneading can be avoided, the silane coupling agent preferably has 4 or less sulfur contained in one molecule. More preferably, those having 2 or less sulfur are preferred. These silane coupling agents can be used alone or in combination of two or more.
The amount of the silane coupling agent is preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight, and particularly preferably 2 to 10 parts by weight with respect to 100 parts by weight of silica.

Examples of carbon black include grades such as N110, N220, N330, N440, and N550. These carbon blacks can be used alone or in combination of two or more.
The specific surface area of carbon black is not particularly limited, but is preferably a nitrogen adsorption specific surface area (N ₂ SA), preferably 5 to 200 m ² / g, more preferably 50 to 150 m ² / g, and particularly preferably 80 to 130 m ^2. / G. When the nitrogen adsorption specific surface area is within this range, the tensile properties are more excellent. The DBP adsorption amount of carbon black is not particularly limited, but is preferably 5 to 300 ml / 100 g, more preferably 50 to 200 ml / 100 g, and particularly preferably 80 to 160 ml / 100 g. When the DBP adsorption amount is within this range, a rubber composition having more excellent tensile properties can be obtained. Further, as carbon black, the adsorption (CTAB) specific surface area of cetyltrimethylammonium bromide disclosed in JP-A-5-230290 is 110 to 170 m ² / g, and compression is repeated four times at a pressure of 24,000 psi. Wear resistance can be improved by using high structure carbon black whose DBP (24M4DBP) oil absorption after addition is 110-130 ml / 100g.
The compounding quantity of carbon black is 1-50 weight part with respect to 100 weight part of rubber components, Preferably it is 2-30 weight part, Most preferably, it is 3-20 weight part.

In the rubber composition of the present invention, a vulcanizing agent can be used preferably in the range of 0.5 to 10 phr, more preferably 1 to 6 phr with respect to 100 phr of all rubber components.
Typical examples of the vulcanizing agent include sulfur, and other examples include sulfur-containing compounds and peroxides.

  Further, in combination with a vulcanizing agent, a vulcanization accelerator such as a sulfenamide-based, guanidine-based, or thiuram-based one may be used as needed. Further, zinc white, vulcanization aid, anti-aging agent, processing aid, and the like may be used as required.

  Furthermore, various compounding agents for the rubber composition obtained using the modified solution-polymerized diene rubber of the present invention are not particularly limited, but include improved workability during kneading, wet skid characteristics, impact resilience, and abrasion resistance. Vulcanizing agent, vulcanization accelerator, zinc white, anti-aging agent, anti-scorching agent, tackifier, other fillers, etc. blended with other extender oils and ordinary rubber compositions for the purpose of further improving the balance of In addition to the various compounding agents described above, compatibilizers such as epoxy group-containing compounds, carboxylic acid compounds, carboxylic acid ester compounds, ketone compounds, ether compounds, aldehyde compounds, hydroxyl group-containing compounds and amino group-containing compounds are selected. Or a silicone compound selected from alkoxysilane compounds, siloxane compounds and aminosilane compounds It can also be added at the time of kneading.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples. The physical properties of the polymer were measured according to the following method.

The weight average molecular weight (Mw) of the polymer was measured by gel permeation chromatography “GPC: HLC-8020 manufactured by Tosoh Corporation, column: GMHXL manufactured by Tosoh Corporation (two in series)”, and the differential refractive index (R1) was used. The measurement was performed in terms of polystyrene using dispersed polystyrene as a standard.
The coupling efficiencies (Cp) shown in Tables 1 and 2 were calculated as follows.
The “four-branched structure by Sn compound (Cp ¹ )” is a diene rubber coupled with a molecular weight peak area of an uncoupled diene rubber on the GPC chart and a nearly four times molecular weight when tin tetrachloride is used. It was calculated | required from the ratio of the peak area corresponding to. Even when this structure was steam-solidified, the coupling efficiency was not substantially changed.
Samples of “bi-branched structure or more (Cp ² ) with Si compound (Cp ² )” were taken out from a polymerization solution immediately after silane compound modification in a sufficiently nitrogen-substituted container, and analyzed after dilution. It was determined from the ratio of the peak area having a molecular weight approximately twice that of the GPC chart before coupling to the total peak area. Under the conditions of the present invention, the peak area corresponding to the three-branched structure could be substantially ignored in the GPC chart after modification with the silane compound.
“Steam-coagulated bi-branched structure or higher (Cp ³ )”, when diene rubber modified with a silane compound was also co-solidified with steam, the ratio of tri- or higher-branched structures increased and overlapped with the peak coupled with the tin compound . Therefore, it calculated | required from the ratio of the peak area 2 times or more of the molecular weight before coupling.
“Increase in coupling efficiency after steam coagulation (ΔCp = Cp ³ −Cp ¹ −Cp ² )” is a difference in coupling efficiency before and after steam coagulation. In general, the storage stability increases as the value increases.

The “steam coagulation test” shown in Tables 1 and 2 was performed as follows, and the determination was made according to the following criteria. For steam coagulation, a normal dispersant is placed in a 50 L vessel with a stirrer, heated to 90 ° C. with steam, and 1 L of the polymerization solution is poured from 35 vessels with 3 mm diameter holes while maintaining at 90 ° C. or higher. It was dropped over 5 minutes and stirred for 60 minutes. The crumb shape to be generated was quantified by 1-5. The larger the value, the better the steam coagulation test.
5: The crumbs have the same size, and the crumbs do not stick together even if stirring is continued.
(It is estimated that no major problems will occur in industrial production.)
3: The crumb sizes are slightly uneven, and the amount of adhesion between crumbs increases when stirring is continued. (Problems occur in industrial production, and some measures are estimated to be necessary.)
1: The crumbs are uneven, and the crumbs start to adhere immediately after falling.
(A big problem occurs in industrial production, and it is impossible to produce, or some big technical measures are essential.)
4,2: is the middle of each.

The styrene unit content in the polymer was calculated from the integral ratio of ¹ H-NMR spectrum. The glass transition point (Tg) of the polymer was measured using a differential scanning calorimeter (DSC) 7 type apparatus manufactured by PerkinElmer Co., Ltd., under the condition of raising the temperature at 10 ° C./min after cooling to −100 ° C.

  The kneading characteristics and physical properties of the vulcanized rubber were measured by the following methods, and the Mooney viscosity of the rubber composition was measured as follows.

The kneading for preparing the vulcanizate of the rubber composition was in accordance with JIS K6299: 2001 “Rubber—Method for Preparing Test Sample”.
The kneading conditions (A kneading) of the rubber composition not containing the vulcanizing agent were using a Laboplast Mill Banbury mixer manufactured by Toyo Seiki Seisakusho Co., Ltd., with a filling rate of about 65% (volume ratio), and a rotor rotational speed of 50 rpm. The kneading start temperature was 90 ° C.
A kneading condition (B kneading) for blending the vulcanizing agent in the rubber composition after kneading was blended with a vulcanizing agent at room temperature using an 8-inch roll manufactured by Daihan Co., Ltd.

The temperature dispersion of the viscoelasticity test is in accordance with JIS K7244-7: 2007 "Plastics-Test method for dynamic mechanical properties-Part 7: Torsional vibration-Non-resonant method" using "TA INSTRUMENTS viscoelasticity measuring device RSA3" The measurement frequency is 10 Hz, the measurement temperature is −50 to 80 ° C., the dynamic strain is 0.1%, the heating rate is 4 ° C./min, and the test piece shape is “width 5 mm × length 40 mm × thickness 1 mm”. Measured with samples.
The smaller tan δ (60 ° C.), the lower the heat generation.

(2) Tensile properties were measured according to JIS K6251: 2004 for strength at break (T _B ), modulus, elongation at break, and the like.

  Abrasion resistance is determined according to JIS K6264-2: 2005 “Vulcanized rubber and thermoplastic rubber – Determination of wear resistance – Part 2: Test method”. The amount was measured. The abrasion resistance of the control sample was taken as 100, and the index was displayed as an abrasion resistance index. A larger index is better.

The Mooney viscosity was measured according to JIS K6300-2001 at a temperature of 100 ° C. [Money viscosity [ML _{1 +} 4/100 _{° C.} ]].
The Mooney viscosities shown in Tables 1 and 2 were calculated as follows.
“MV (a) after steam coagulation / drying” measured the Mooney viscosity after drying the steam-coagulated crumb at a roll temperature of 110 ° C. for 30 minutes.
In “MV (b) after 130 ° C. roll mill”, the drying temperature of the rubber was further raised to 130 ° C. and passed through the roll mill for 20 minutes, and then the Mooney viscosity was measured.
“ΔMV” is the difference in MV measured above, and the amount of increase in MV indicated by (b−a). The smaller this value, the better the storage stability.

[Example 1] and [Comparative Example 1]
An autoclave having an internal volume of 10 L was sufficiently substituted with dry nitrogen, charged with 5500 g of cyclohexane, 556 mg (3.02 mmol) of 2,2-di (2-tetrahydrofuryl) propane (DTHFP), 200 g (1.92 mol) ) Styrene, 760 g (14.05 mol) of 1,3-butadiene was placed in an autoclave. After adjusting the temperature in the autoclave to 25 ° C., a reaction product of 10 g of isoprene and 428 mg (5.03 mmol) of piperidine and 322 mg (5.03 mmol) of n-butyllithium was added to the autoclave in a separate container of cyclohexane. The polymerization was started. The polymerization increased adiabatically and the maximum temperature reached 88 ° C. At this point, 30 g of 1,3-butadiene was added and polymerization was carried out for an additional 5 minutes. Thereafter, 52.4 mg (0.201 mmol) of tin tetrachloride was added and reacted for 5 minutes. Here, 20 mL of the polymerization solution was extracted from the autoclave into a container sufficiently purged with nitrogen for analysis, later diluted and subjected to GPC analysis, and the rest was steam-coagulated. Subsequently, 1.29 g (4.20 mmol) of methyltris [2- (dimethylamino) ethoxy] silane was added to the autoclave and reacted for 15 minutes. According to GPC analysis, the molar ratio of the active diene rubber and the silane compound was 1.3. Further, 213 mg (1.26 mmol) of silicon tetrachloride was added and reacted for 5 minutes. Finally, 2,6-di-tert-butyl-p-cresol was added to the polymerization solution. 3000 g of the polymerization solution was dried by a direct removal method. This rubber was designated as (Comparative Example 1). The remaining solution was dissolved by a steam coagulation method and dried with a roll at 110 ° C. This rubber was referred to as (Example 1). Table 1 summarizes the results of analysis such as GPC analysis, styrene content and vinyl content in diene rubber. Although the difference between Example 1 and Comparative Example 1 is the drying method, the direct dehydration method of Comparative Example 1 has a large difference in storage stability, which is a big problem for industrial production.

[Comparative Example 2]
A modified solution-polymerized diene rubber was produced in the same manner as in Example 1 except that 163 mg of tin tetrachloride corresponding to half the equivalent of n-butyllithium used as the polymerization initiator in Example 1 was added. The analysis results are summarized in Table 1. Compared with Example 1, the 4-branch structure by Sn compound is increasing about 3 times.

[Example 2]
A modified solution polymerized diene rubber was produced in the same manner as in Example 1 except that the isoprene used in the prepolymerization was eliminated in Example 1. The analysis results are summarized in Table 1. There is no significant difference in manufacturing.

[Comparative Example 3]
In Example 1, a modified solution polymerized diene rubber was produced in the same manner as in Example 1 except that the coupling with tin tetrachloride was eliminated. The analysis results are summarized in Table 1. In the steam coagulation test, crumbs adhere to each other, which is a big problem for industrial production.

[Example 3]
A modified solution-polymerized diene rubber was produced in the same manner as in Example 1 except that the isoprene used for the prepolymerization in Example 1 and the addition of silicon tetrachloride were eliminated. The analysis results are summarized in Table 1. Regarding production, the steam coagulation test was slightly worse, but no other significant difference was seen.

[Example 4]
The autoclave with an internal volume of 10 L was sufficiently substituted with dry nitrogen, charged with 5500 g of cyclohexane, 154 g of tetrahydrofuran (THF), 200 g (1.92 mol) of styrene, 760 g (14.05 mol) of 1,3-butadiene. Placed in autoclave. After adjusting the temperature in the autoclave to 25 ° C., 428 mg (5.03 mmol) of piperidine and 322 mg (5.03) mmol) of n-butyllithium were sequentially added directly to the autoclave to initiate polymerization. The polymerization increased adiabatically and the maximum temperature reached 91 ° C. At this point, 40 g of 1,3-butadiene was added and polymerization was carried out for an additional 5 minutes. Thereafter, 52.4 mg (0.201 mmol) of tin tetrachloride was added and reacted for 5 minutes. Here, 20 mL of the polymerization solution was extracted from the autoclave into a container sufficiently purged with nitrogen for analysis, later diluted and subjected to GPC analysis, and the rest was steam-coagulated. Subsequently, 0.861 g (4.83 mmol) of methyltriethoxysilane was added to the autoclave and reacted for 15 minutes. According to GPC analysis, the molar ratio of the active diene rubber to the silane compound was 1.5. Further, 213 mg (1.26 mmol) of silicon tetrachloride was added and reacted for 5 minutes. Finally, 2,6-di-tert-butyl-p-cresol was added to the polymerization solution. This solution was dissolved by a steam coagulation method and dried with a roll at 110 ° C. This rubber was referred to as (Example 4). The analysis results are summarized in Table 2.

[Example 5]
In Example 4, a modified solution polymerized diene rubber was produced in the same manner as in Example 4 except that the amount of styrene was increased to 250 g, the initial 1,3-butadiene was reduced by 710 g, and piperidine was not used. The analysis results are summarized in Table 2. There is no significant difference in manufacturing.

[Example 6]
A modified solution polymerized diene rubber was produced in the same manner as in Example 4 except that equimolar (N, N-dimethyl-3-aminopropyl) triethoxysilane was used in place of methyltriethoxysilane. The analysis results are summarized in Table 2. There is no significant difference in manufacturing.

[Example 7]
In Example 6, a modified solution-polymerized diene rubber was produced in the same manner as in Example 6 except that silicon tetrachloride was not used after addition of the silane compound. The analysis results are summarized in Table 2. The steam coagulation test is a bit worse, but there is no significant difference for other productions.

[Comparative Example 4]
In Example 6, a modified solution-polymerized diene rubber was produced in the same manner as in Example 6 except that piperidine as a polymerization initiator component, tin tetrachloride after polymerization, and silicon tetrachloride after addition of the silane compound were not used. The analysis results are summarized in Table 2. The steam coagulation test deteriorated, and the storage stability deteriorated greatly.

[Examples 8 to 14 and Comparative Examples 5 to 7]
The modified solution-polymerized diene rubbers produced as prototypes in Examples 1 to 7 and Comparative Examples 2 to 4 were blended according to the vulcanized physical composition recipes shown in Table 3, and the vulcanized physical properties were evaluated. The evaluation results are shown in Table 4. In Comparative Example 1, the storage stability was very poor and the evaluation of physical properties was omitted because the industrial possibility was low.
Table 4 shows the formulation MV, tensile strength, elongation at break, modulus ratio of M ₃₀₀ / M ₁₀₀ , acron wear resistance, and dynamic viscoelasticity test results. The physical property values shown in the index are represented by Comparative Example 5 as 100, and the larger the numerical value of any item, the better the physical properties.
A larger value of the modulus ratio, which is a measure of reinforcement, and a lower value of the blending MV are better. Comparative Example 5 is a low blending MV, but the modulus ratio is small and the reinforcing property with silica is considered low, and the vulcanized physical properties are not good.
The higher the reinforcing strength with silica, the higher the tensile strength, and the higher the correlation with Akron abrasion resistance.
The tan δ (0 ° C.) was mainly governed by the styrene content and vinyl structure of the diene rubber, and there was no significant difference in any of the diene rubbers prototyped in the present invention.
Tan δ (60 ° C.) is influenced by the reinforcing property with silica and the dispersibility of silica, and the higher the reinforcing property and the better the dispersibility, the larger the value.
From these physical property evaluation results and the like, the modified solution polymerized diene rubber of the present invention has good productivity, high storage stability, and good vulcanized physical properties.

Claims (9)

i) Initiating polymerization of a conjugated diene compound and an aromatic vinyl compound in a hydrocarbon in the presence of an organolithium compound or a secondary amine compound,
ii) After completion of the polymerization, a tin compound represented by the formula (1) is added, and the diene rubber is treated so that the components of 3 or more branches are 5 to 30%,
iii) Subsequently, a silane compound represented by the formula (2) is added and treated so that the bi-branched component of the diene rubber is 30% or less,
iv) The obtained polymer composition is steam-coagulated and dried to increase the content of two or more branches by 10 to 50% with respect to the state before steam coagulation, and the Mooney viscosity (a ) Is further heat-stabilized to such an extent that the Mooney viscosity (b) fluctuates by not more than 10 when heat-treated for 20 minutes in a subsequent roll mill at 130 ° C., a method for producing a modified solution-polymerized diene rubber.
Here, R ¹ is an alkyl group having 1 to 12 carbon atoms, an aromatic group, or an allyl group, X is a halogen compound of iodine, bromine, or chlorine, n is an integer, 0 or 1 It is.
Here, R ² is an alkyl group having 1 to 12 carbon atoms, an aromatic group, an allyl group, or an alkyl group, an aromatic group or an allyl group containing a nitrogen atom in these functional groups, and R ³ is carbon. An alkyl group or an aromatic group having 1 to 12 atoms, an allyl group, or an alkyl group or an aromatic group or an allyl group containing an oxygen atom and / or a nitrogen atom in these functional groups, m is an integer, 4.   The method for producing a modified solution-polymerized diene rubber according to claim 1, wherein the polymerization is initiated in the presence of an organic lithium compound and a secondary amine compound.   The method for producing a modified solution-polymerized diene rubber according to claim 1 or 2, wherein after the prepolymerization of isoprene with an organolithium compound, another conjugated diene compound and an aromatic vinyl compound are polymerized.   The method for producing a modified solution-polymerized diene rubber according to any one of claims 1 to 3, wherein after the prepolymerization in the presence of an organic lithium compound, a secondary amine compound, and isoprene, another conjugated diene compound and an aromatic vinyl compound are polymerized. .   The modified solution polymerization according to any one of claims 1 to 4, wherein the steam coagulation / drying in the step iv) is performed such that components of two or more branches are increased by 20 to 40% with respect to the state before the steam coagulation / drying. Method for producing diene rubber.   The modified solution-polymerized diene system according to any one of claims 1, 3, and 5, wherein after the prepolymerization of 10% by weight or less of isoprene with an organolithium compound, another conjugated diene compound and an aromatic vinyl compound are polymerized. Rubber production method. Claim iii) After the step iv), before the step iv), the metal halide compound represented by the formula (3) in an amount satisfying the formula (4) is added, and then iv) the steam coagulation / drying in the step is performed. The manufacturing method of the modified | denatured solution polymerization diene rubber of Claims 1-6.
Here, M is a tin atom or a silicon atom, R ⁴ is an alkyl group having 1 to 12 carbon atoms, an aromatic group, an allyl group, or a carboxyl group, and X is any one of iodine, bromine, and chlorine Halogen compound, p is an integer and is 0 or 1.
Here, L is the number of moles of the organolithium compound added at the start of polymerization, A is the number of moles of the tin compound of the formula (1) added, and B is the metal halide compound shown by the added formula (3) N and p are integers represented by formula (1) and formula (3), respectively.   A rubber composition containing at least 20 to 150 phr of silica with respect to 100 phr of all rubber components containing at least 20 phr or more of the modified solution polymerized diene rubber according to claim 1.   A rubber composition containing at least 20 to 150 phr of silica and 5 to 30 phr of carbon black with respect to 100 phr of all rubber components containing at least 20 phr or more of the modified solution-polymerized diene rubber according to claim 1.