Modified conjugated diene polymer compositions, manufacturing processes of modified conjugated diene polymer compositions, and vulcanized product

Abstract

Modified conjugated diene polymer composition, comprising a rubber component A comprising a modified conjugated diene polymer obtained by reacting a conjugated diene polymer with a nitrogen-containing compound and having a glass transition temperature of -35°C or higher, a rubber component B obtained by reacting a conjugated diene polymer with a nitrogen-containing compound and having a glass transition temperature of -55°C or lower, and a silicon dioxide-containing filler, wherein the proportion of rubber component A in relation to the total amount of rubber component A and rubber component B is 50% to 95% by mass, The rubber component A has a weight-averaged molecular weight of 20 × 10 4 up to 300 × 10 4 and has a molecular weight distribution Mw / Mn of 1.6 to 4.0, the degree of modification of the rubber component A, determined on the basis of a chromatogram obtained by gel permeation chromatography (GPC), is 50 wt% or higher, and The rubber component B is a modified conjugated diene polymer selected from a statistical copolymer of a conjugated diene compound and a vinylaromatic compound, a hydrogenated product thereof, a block copolymer of a conjugated diene compound and a vinylaromatic compound, and a hydrogenated product thereof.

Description

[Field of invention]

[0001] This invention relates to a modified conjugated diene polymer composition, a production process of the modified conjugated diene polymer composition and a vulcanized product, in particular a tire. [Description of the prior art]

[0002] In recent years, winter tires have been expected to improve not only their mileage on snowy roads (snow performance) but also their mileage on wet roads (wet performance).

[0003] Furthermore, due to the societal expectation to reduce the burden on the global environment, tires are required to extend their service life and to achieve this, there is a strong demand to improve abrasion resistance as one of the tire performances.

[0004] Methods have also been proposed, such as reducing the amount of filler to be added and increasing the amount of oil to be added, in order to improve snow performance, to reduce the elastic modulus at low temperatures and thus to ensure high traceability of the tread rubber on snow-covered roads.

[0005] However, these methods have the disadvantage that wet performance and abrasion resistance can tend to deteriorate.

[0006] On the other hand, in order to improve the wet performance, methods have also been proposed to improve the glass transition temperature of the rubber composition or to increase the energy loss by increasing the amount of fillers to be added.

[0007] However, these methods tend to have the disadvantage that they increase the elastic modulus at low temperatures and may therefore deteriorate snow performance.

[0008] As winter roads become increasingly better prepared, it is becoming increasingly important for winter tires to improve performance not only on snowy roads but also on wet roads.

[0009] Patent Document 1 proposes a rubber composition in which both snow performance and wet performance can be improved by mixing rubber components with different glass transition temperatures. [Documents relating to the prior art][Patent documents]

[0010] [Patent Document 1] JP 2005-154473 A

[0011] WO 2018 / 164053 A1 (EP 3 594 251 A1) discloses a modified conjugated diene polymer having a weight-average molecular weight of 20 × 10 4 up to 300 × 10 4 and a molecular weight distribution Mw / Mn of 1.6 to 4.0, wherein the modification degree is 50%, the modification degree of a low molecular weight component is 1 / 2 or more of the modification degree with respect to the total amount of the conjugated diene-based polymer, and the nitrogen content is 3 to 70 ppm by mass. [Description of the invention][Description of the technical problem underlying the invention]

[0012] However, the rubber composition described in Patent Document 1 still has the problem that the reactivity between the modified group of the end-modified styrene-butadiene rubber and the silica is insufficient, and therefore there is still further potential for improving the snow performance and wet performance.

[0013] The object of the present invention is therefore to provide a modified conjugated diene polymer composition in which the dispersibility of the silica as a filler is excellent, and from which a rubber composition having an excellent balance between snow performance and wet performance as well as excellent friction resistance can be obtained. [Description of the problem solution through the invention]

[0014] As a result of intensive studies to solve the above-described problems of the prior art, the inventors of the present invention have found that in the modified conjugated diene polymer compositions containing the rubber component A and the rubber component B, in which the glass transition temperatures are different, and filler, by setting the content of the rubber component A whose glass transition temperature is higher than that of the above-mentioned rubber component B, the weight-average molecular weight, the molecular weight distribution and the degree of modification, the balance between the snow performance and the wet performance can be improved and at the same time excellent abrasion resistance can be obtained, and thereby the present invention has been completed.

[0015] The invention is set out in the claims. [Statement of the advantages achieved by the invention]

[0016] This invention therefore makes it possible to provide a modified conjugated diene polymer composition from which a rubber composition having an excellent balance between snow performance and wet performance and excellent friction resistance can be obtained. [Embodiments of this invention]

[0017] In the following, the forms for carrying out this invention are explained in more detail (hereinafter referred to as "embodiments according to the invention").

[0018] The following embodiments of the invention are examples for explaining the invention, and the invention is in no way limited to the following contents. [modified conjugated diene polymer composition]

[0019] A modified conjugated diene polymer composition according to this embodiment comprises a rubber component A, which is obtained by reacting a conjugated diene polymer with a nitrogen-containing compound and has a glass transition temperature of -35°C or higher, a rubber component B, defined below, which is obtained by reacting a conjugated diene polymer with a nitrogen-containing compound and has a glass transition temperature of -55°C or lower, and silica-containing filler, wherein the proportion of the above-mentioned rubber component A relative to the total amount of the above-mentioned rubber component A and the above-mentioned rubber component B is 50% by mass to 95% by mass, wherein the above-mentioned rubber component A has a weight-average molecular weight of 20 × 10 4 up to 300 × 10 4and a molecular weight distribution Mw / Mn of 1.6 to 4.0, the degree of modification of the above-mentioned rubber component A is 50 mass% or higher. (modified conjugated diene polymer (rubber component A))

[0020] A modified conjugated diene polymer composition according to this embodiment contains the rubber component A, which is a modified conjugated diene polymer having a glass transition temperature of -35°C or higher.

[0021] The rubber component A has a weight-average molecular weight of 20 × 10 4 up to 300 × 10 4 and a molecular weight distribution Mw / Mn of 1.6 to 4.0, and its modification degree is 50 mass% or higher relative to the total amount of conjugated diene polymer.

[0022] In order to improve the friction resistance, the weight-average molecular weight of the rubber component A should preferably be 50 × 10 4 up to 300 × 10 4 If the weight-average molecular weight is 50 × 10 4 or more, the amount of polymerization initiator to be used can be reduced, thus increasing the influences of growth reaction termination or chain transfer on the modification degree of the component with a molecular weight half the peak molecular weight on the GPC curve. Therefore, unless extremely high purity of the monomers and solvents fed into the polymerization reactor, polymerization at a low temperature, and a monomer conversion rate of less than 99 mass% can be achieved, it becomes difficult to obtain a modified conjugated diene polymer with a desired modification degree.

[0023] The rubber component A constituting the modified conjugated diene polymer composition according to this embodiment is considered to be a suitable embodiment when, as explained later, it determines the degree of modification of the particular low-molecular component, and therefore, the weight-average molecular weight of the above-mentioned rubber component A is preferably 50 × 10 4 or larger.

[0024] The modified conjugated diene polymer composition according to this embodiment contains the above-mentioned rubber component A in 50 mass% or more of the total amount of the above-mentioned rubber component A and the rubber component B. This increases the glass transition temperature of the modified conjugated diene polymer composition according to this embodiment, thus tending to improve wet performance. This value is preferably 55 mass% or more, and more preferably 60 mass% or more.

[0025] Furthermore, the upper limit should be 95% by mass or less, preferably 90% by mass or less, and more preferably 80% by mass or less. When the proportion of rubber component A is 95% by mass or less, the vulcanizate becomes softer at low temperatures, thus tending to improve snow performance. (Production process of modified conjugated diene polymer (rubber component A))

[0026] A modified conjugated diene polymer (rubber component A) is prepared by the polymerization process and modification process mentioned below. < Polymerization process >

[0027] In a polymerization process of a modified conjugated diene polymer (rubber component A), at least the conjugated diene compounds are polymerized using organic lithium compounds as polymerization initiator, thereby obtaining conjugated diene polymer.

[0028] In this polymerization process, the polymerization is preferably carried out by the growth reaction of a living anionic polymerization reaction, thereby a conjugated diene polymer having active ends can be obtained, and therefrom a modified conjugated diene polymer having a high degree of modification can tend to be obtained.

[0029] In the polymerization process, at least the conjugated diene compound is polymerized, and if necessary, the conjugated diene polymer is obtained by copolymerizing a conjugated diene compound with a vinyl aromatic compound.

[0030] As long as it is a polymerizable monomer, there is no limitation on the conjugated diene compound, and it is preferably a conjugated diene compound having 4 to 12 carbon atoms per one molecule, and more preferably a conjugated diene compound having 4 to 8 carbon atoms.

[0031] Examples of such conjugated diene compounds include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, etc.

[0032] Of these examples, 1,3-butadiene and isoprene are preferred for light industrial supply. These can be used individually or in combinations of two or more types.

[0033] An extremely high degree of purity of the monomers and solvents can be achieved by sufficiently purifying all monomers and solvents used for polymerization.

[0034] When purifying butadiene, which is one of the monomers, it is essential to remove the polymerization inhibitor. It is also important to remove dimethylamine, N-methyl-γ-aminobutyric acid, etc., which can adversely affect anionic polymerization. One method for removing the above-mentioned substances is to wash 1,3-butadiene containing the polymerization inhibitor using low-oxygen purification water with an oxygen concentration of less than 2 mg / L, thereby removing the polymerization inhibitor from 1,3-butadiene.

[0035] When purifying styrene, one of the monomers, it is important to eliminate phenylacetylene and the like, which can adversely affect anionic polymerization. One method for eliminating phenylacetylene and the like is a method in which hydrogenation is carried out using a palladium-supporting alumina catalyst.

[0036] When purifying normal hexane, one of the polymerization solutions, it is important to remove moisture, which can adversely affect anionic polymerization. A method for removing moisture can be cited, such as using γ-alumina, synthetic zeolite, etc. Among these examples, the synthetic zeolite method is preferred, and a synthetic zeolite with a large pore diameter is suitable, preferably 0.35 nm or larger, and more preferably 0.42 nm or larger.

[0037] Since ultra-high purification required to adjust the appropriate impurity concentration differs depending on the condition before treatment, it is advantageous to measure the impurity concentration of the monomers and solvents after the ultra-high purification of the monomers and solvents before polymerization.

[0038] If the desired impurity concentration of the monomers and / or solvents was not achieved, at least one of the treatments was likely insufficient. If the amount of primary and secondary amines needs to be further reduced, the butadiene purification was insufficient, so it should preferably be washed again, for example, with low-oxygen water as cleaning water, where the oxygen concentration is less than 2 mg / L. If the acetylene content needs to be further reduced, the styrene purification was insufficient, so hydrogenation should preferably be carried out again, for example, using a palladium-supported alumina catalyst. The treatment should be carried out, for example, by increasing the amount of the palladium-supported alumina catalyst or by extending the contact time with the palladium-supported alumina catalyst.

[0039] As vinyl-substituted aromatic compounds, any monomers can be used without particular restriction as long as they are polymerizable with a conjugated diene compound, with a monovinyl aromatic compound being preferred.

[0040] Examples of monovinyl aromatic compounds include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, diphenylethylene, etc. Of these, styrene is preferred for ease of industrial supply. These can be used individually or in combinations of two or more types.

[0041] A conjugated diene polymer obtained during the polymerization process can be a random copolymer or a block copolymer.

[0042] In order to make a conjugated diene polymer obtained in the polymerization process into a rubbery polymer, it is preferable to use 40 mass% or more, and more preferably 55 mass% or more of the conjugated diene compound based on the total monomer of the conjugated diene polymer.

[0043] As the random copolymers, there can be mentioned, for example, a random copolymer such as butadiene-isoprene random copolymer, etc., which consists of two or more conjugated diene compounds, and random copolymers consisting of a conjugated diene and a vinyl-substituted aromatic compound such as butadiene-styrene random copolymer, isoprene-styrene random copolymer, butadiene-isoprene-styrene random copolymer.

[0044] The composition distribution of each monomer in the copolymer chain is not particularly limited. Examples include a completely random copolymer in which the composition is almost random, and a wedge (gradient) random copolymer in which the composition is distributed in a wedge shape. The compound type of the conjugated diene, such as 1,4-compound, 1,2-compound, etc., in the composition can be homogeneous or have a certain distribution.

[0045] Block copolymers include, but are not limited to, a 2-block copolymer consisting of two blocks (di-block), a 3-block copolymer consisting of three blocks (tri-block), a 4-block copolymer consisting of four blocks (tetra-block), etc. A polymer forming a block may be a polymer consisting of one type of monomer or a copolymer consisting of two or more types of monomers. For example, when a polymer block of 1,3-butadiene is represented as “B”, a copolymer of 1,3-butadiene and isoprene is represented as “B / I”, a copolymer of 1,3-butadiene and styrene as “B / S”, a polymer block of styrene is represented as “S”, they can be referred to as a BB / I2 type block copolymer, BB / S2 type block copolymer, S-B2 type block copolymer, BB / S-S3 type block copolymer, SB-S3 type block copolymer, SBS-B4 type block copolymer, etc.

[0046] In the above formula, the boundaries do not necessarily have to be clearly distinguished. Furthermore, if a polymer block is a copolymer consisting of two types of monomers, A and B, it is possible that A and B may be distributed homogeneously or wedge-shaped within the block. [Polymerization initiator]

[0047] As already mentioned, at least one organic lithium compound is used as a polymerization initiator in the polymerization process.

[0048] Organic lithium compounds may include, but are not limited to, low molecular weight compounds, solubilized oligomers of the organic lithium compound, etc.

[0049] Furthermore, the organic lithium compounds, sorted by their bond type between the organic group and the lithium compound, include a compound with a carbon-lithium bond, a compound with a nitrogen-lithium bond and a compound with a tin-lithium bond.

[0050] The amount of polymerization initiator to be used should preferably be determined depending on the molecular weight of the desired conjugated diene polymer or modified conjugated diene polymer. The amount of conjugated diene compound, etc., to be used relative to the amount of polymerization initiator used influences the degree of polymerization. That is, it tends to influence the number-average molecular weight and / or the weight-average molecular weight. Therefore, to increase the molecular weight, the amount of polymerization initiator should be reduced, and to decrease the molecular weight, an increased amount of polymerization initiator should be used.

[0051] The organic lithium compound used as a polymerization initiator should be an alkyllithium compound due to its industrial availability and ease of control of the polymerization reaction. In this case, a conjugated diene polymer with an alkyl group at the polymerization initiation end is obtained.

[0052] As the above-mentioned alkyllithium compounds serving as polymerization initiators, there may be mentioned, for example, but not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium and stilbenelithium.

[0053] n-Butyllithium and sec-butyllithium are suitable as alkyllithium compounds due to their industrial availability and easy control of the polymerization reaction.

[0054] A method using compounds having a nitrogen-lithium bond (hereinafter also referred to as lithium amide compound) as a polymerization initiator is used as one of the methods for introducing nitrogen into the conjugated diene polymer. Examples of such a lithium amide compound include an alkyllithium compound having a substituted amino group or a dialkylaminolithium compound. In this case, a conjugated diene polymer and a modified conjugated diene polymer having a nitrogen atom of the amino group, which has a functional group represented by, for example, the following formula (1) at the polymerization initiation terminal, are obtained.

[0055] By introducing the nitrogen atom into the conjugated diene polymer, the hysteresis loss and wet skid resistance can be improved.

[0056] In the above general formula (1), R 1 and R 2 each represents a functional group selected from the group consisting of alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 14 carbon atoms, and aryl groups having 6 to 20 carbon atoms, and they may be identical or different. Here, R 1 and R 2 and form a ring structure with the neighboring nitrogen atom, and in this case the sum of the carbon atoms of R 1 and R 2 4 to 12. R 1 and R 2 may have an unsaturated compound or a branched structure.

[0057] As the above-mentioned alkyllithium compounds or dialkylaminolithium compounds having a substituted amino group, for example, compounds which can be represented by the following general formula (2) can be mentioned.

[0058] In the above general formula (2), R 1 and R 2 each represents a functional group selected from the group consisting of alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 14 carbon atoms, and aryl groups having 6 to 20 carbon atoms, and they may be identical or different. Here, R 1 and R 2 and form a ring structure with the neighboring nitrogen atom, and in this case the sum of the carbon atoms of R 1 and R 2 4 to 12. R 1 and R 2 may have an unsaturated compound or a branched structure.

[0059] As compounds that can be expressed by the above-mentioned formula (2), there can be mentioned, for example, but are not limited to, 1-lithiopyrrolidine, 1-lithiopiperidine, 1-lithioazacycloheptane, 1-lithioazacyclooctane, 1-lithioazacycloundecane, lithium diethylamide, lithium dibutylamide, lithium dihexylamide, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, lithium ethylbutylamide, lithium ethylhexylamide, lithium butylhexylamide, lithium methylphenylamide, lithium benzylmethylamide, 1-lithio-1,2,3,4-tetrahydropyridine, etc. The compounds that can be expressed by the above-mentioned formula (2) are not limited thereto, and similar compounds can be included as long as they satisfy the above-mentioned conditions.

[0060] With regard to reducing the hysteresis loss of the modified conjugated diene polymer composition according to this embodiment, suitable compounds represented by the above-mentioned formula (2) include 1-lithiopyrrolidine, 1-lithiopiperidine, 1-lithioazacycloheptane, lithium dibutylamide, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, 1-lithio-1,2,3,4-tetrahydropyridine, etc.

[0061] Even more preferably, 1-lithiopyrrolidine, 1-lithiopiperidine and 1-lithioazacycloheptane are suitable for this purpose, further preferably 1-lithiopiperidine and 1-lithioazacycloheptane.

[0062] The lithium amide compound as a polymerization initiator mentioned above can be synthesized by a previously known method.

[0063] For example, it can be obtained by reacting secondary amine and organic lithium compound in a hydrocarbon solvent.

[0064] As hydrocarbon solvents, there may be mentioned, but are not limited to, hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons, etc. Specifically, there may be mentioned aliphatic hydrocarbons such as butane, pentane, hexane, heptane, etc.; cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, etc.; aromatic hydrocarbons such as benzene, toluene, xylene, etc.; and mixed hydrocarbons thereof, etc.

[0065] Examples of secondary amines that can be mentioned include, but are not limited to, the compounds represented by the following formula (3).

[0066] In the above general formula (3), R 1 and R 2each a functional group selected from the group consisting of alkyl groups having 1 to 12 carbon atoms, cycloalkyl groups having 3 to 14 carbon atoms, and aryl groups having 6 to 20 carbon atoms, and they may be identical or different. R 1 and R 2 can be connected and form a ring structure with the neighboring nitrogen atom, and in this case the sum of the carbon atoms of R 1 and R 2 4 to 12. R 1 and R 2 may have an unsaturated compound or a branched structure.

[0067] Examples of compounds that can be expressed by the above-mentioned formula (3) include pyrrolidine, piperidine, azacycloheptane, azacyclooctane, azacycloundecane, diethylamine, dibutylamine, dihexylamine, 1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, ethylbutylamine, ethylhexylamine, butylhexylamine, methylphenylamine, benzylmethylamine, 1,2,3,4-tetrahydropyridine, etc. The compounds that can be expressed by the above-mentioned formula (3) are not limited thereto, and similar compounds can be included as long as they satisfy the above-mentioned conditions.

[0068] With regard to reducing the hysteresis loss of the modified conjugated diene polymer composition according to this embodiment, suitable compounds represented by the above-mentioned formula (3) include pyrrolidine, piperidine, azacycloheptane, dibutylamine, 1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, 1,2,3,4-tetrahydropyridine, etc. Pyrrolidine, piperidine, and azacycloheptane are even more preferred. Piperidine and azacycloheptane are even more preferred.

[0069] The lithium amide compound can also be used as an organic monolithium compound of polymerizable monomers, for example, oligomers made soluble by a reaction of a few monomers such as 1,3-butadiene, isoprene, styrene, etc.

[0070] The above-mentioned organic monolithium compounds as polymerization initiator can be used individually, but also in combination of two or more types together.

[0071] Furthermore, these can be used together with (another) organic metal compound(s). Examples of such organic metal compounds include alkaline earth metal compounds, other alkali metal compounds, and other organic metal compounds.

[0072] Examples of alkaline earth metal compounds include, but are not limited to, organic magnesium compounds, organic calcium compounds, and organic strontium compounds.

[0073] Furthermore, compounds with alkoxide, sulfonate, carbonate and amide etc. of alkaline earth metals can be mentioned.

[0074] Examples of organic magnesium compounds include dibutylmagnesium, ethylbutylmagnesium, etc.

[0075] Other organic metal compounds include, for example, organic aluminum compounds.

[0076] A continuous polymerization process is suitable as a type of polymerization reaction in the polymerization process.

[0077] In a continuous process, one or two or more connected reactors can be used for polymerization.

[0078] A tank with a stirring device, tubes, etc. can be used as a reactor for a continuous process.

[0079] In a continuous process, the monomer(s), the inert solvent(s) and the polymerization initiator are preferably continuously fed to the reactor, a polymer solution containing polymer is obtained in this reactor, and then the polymer solution is continuously discharged. [Polymerization solvent]

[0080] In the polymerization process, an inert solvent should be used as the polymerization solvent, and the polymerization should preferably be carried out in this inert solvent.

[0081] Examples of inert solvents include, but are not limited to, hydrocarbon solvents such as saturated hydrocarbons, aromatic hydrocarbons, etc. Examples of hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; and mixed hydrocarbons thereof.

[0082] By treating allenes and acetylenes, which are impurities, with an organic metal compound before using them in the polymerization reaction, a conjugated diene polymer having a high concentration of active end groups can be obtained and a modified conjugated diene polymer having a high modification rate can be obtained, so this is preferred. [Polar connection]

[0083] During the polymerization process, a polar compound(s) can be added. By adding a polar compound, the aromatic vinylaromatic compound and the conjugated diene compound can be polymerized randomly, and this compound also tends to be used as a vinylating agent to regulate the microstructure of the conjugated diene moiety. Furthermore, this also tends to accelerate the polymerization reaction, among other things.

[0084] Examples of polar compounds that can be mentioned, but are not limited to, are ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, 2,2-bis(2-oxolanyl)propane, etc.; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, quinuclidine, etc.; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butylate, sodium tert-butylate, sodium amylate, etc.; and phosphine compounds such as triphenylphosphine.

[0085] These polar compounds can be used individually or in combination of two or more types together.

[0086] The amount of polar compounds to be used is not particularly limited and can be selected depending on the application, preferably 0.01 mol or more but 100 mol or less compared to 1 mol of the above-mentioned polymerization initiator. Such a polar compound (vinylating agent) can be used as a microstructure regulating agent of the conjugated diene portion of the polymer in an appropriate amount depending on the amount of the desired vinyl compound.

[0087] Many polar compounds also exhibit a randomization effect, which is useful in the copolymerization between conjugated diene compounds and aromatic vinyl compounds, and tend to be useful as control agents for controlling the distribution of aromatic vinyl compounds and for controlling the number of styrene blocks. As a method for randomizing conjugated diene compounds and aromatic vinyl compounds, for example, a method described in JP A S59-140211 can be used, in which the copolymerization reaction is initiated with the entire amount of styrene and a portion of 1,3-butadiene, and the remaining 1,3-butadiene is added discontinuously during the copolymerization. < Physical properties of modified conjugated diene polymers >

[0088] In the modified conjugated diene polymer composition (rubber component A) constituting the modified conjugated diene polymer composition according to this embodiment, the degree of modification of the component having a molecular weight equal to half of the molecular weight at the peak top of the GPC curve (the low molecular weight component) or, when multiple peaks are present, at the smallest peak top, should preferably be half of the degree of modification of the total amount of the conjugated diene polymer or more.

[0089] Furthermore, when the rubber component B mentioned later is to be a modified conjugated diene polymer, also in this rubber component B, the degree of modification of the component having a molecular weight corresponding to half the molecular weight at the peak top of the GPC curve, or, if there are multiple peaks, at the smallest peak top, should preferably be half the degree of modification of the total amount of the conjugated diene polymer or more.

[0090] This can be explained by the fact that the low molecular weight component in the entire polymer contributes to the processability of the polymer, since the processability to the vulcanizate tends to be excellent if the above-mentioned range is maintained.

[0091] In order to obtain the above-mentioned modified conjugated diene polymers with a certain degree of modification (rubber component A, rubber component B), it is effective to apply a polymerization method for obtaining the conjugated diene polymer in which polymerization with extremely rare termination of the growth reaction or chain transfer is carried out in the polymerization process.

[0092] To achieve this, the purity of the monomers and solvent introduced into the polymerization reactor must be extremely higher than in a conventional process.

[0093] Therefore, in the monomer component to be used, the total content of impurities is preferably 30 ppm or less, and the contained concentration (mass) of impurities such as allene species, acetylene species, primary and secondary amine species, and specifically, for the allene species, it is preferably 20 ppm or less, more preferably 10 ppm or less, for the acetylene species, it is preferably 20 ppm or less, more preferably 10 ppm or less, for the primary and secondary amine species, as a total nitrogen content, it is preferably 4 ppm or less, and more preferably 2 ppm or less.

[0094] Examples of allene types include, but are not limited to, propadiene, 1,2-butadiene, etc. Examples of acetylene groups include, but are not limited to, ethylacetylene, vinylacetylene, etc. Examples of primary and secondary amines include, but are not limited to, methylamine, dimethylamine, etc.

[0095] An extremely high degree of purity of the monomers and solvents can be achieved by sufficiently purifying all monomers and solvents used for polymerization.

[0096] When purifying butadiene, which is one of the monomers, it is essential to remove the polymerization inhibitor. It is also important to remove dimethylamine, N-methyl-γ-aminobutyric acid, etc., which can adversely affect anionic polymerization. One method for removing the above-mentioned substances is to wash 1,3-butadiene containing the polymerization inhibitor using low-oxygen purification water with an oxygen concentration of less than 2 mg / L, thereby removing the polymerization inhibitor from 1,3-butadiene.

[0097] When purifying styrene, one of the monomers, it is important to eliminate phenylacetylene and the like, which can adversely affect anionic polymerization. One method for eliminating phenylacetylene and the like is a method in which hydrogenation is carried out using a palladium-supporting alumina catalyst.

[0098] When purifying normal hexane, one of the polymerization solutions, it is important to remove moisture, which can adversely affect anionic polymerization. A method for removing moisture can be cited, such as using γ-alumina, synthetic zeolite, etc. Among these examples, the synthetic zeolite method is preferred, and a synthetic zeolite with a large pore diameter is suitable, preferably 0.35 nm or larger, and more preferably 0.42 nm or larger.

[0099] As a polymerization method with extremely little growth reaction stopper or chain transfer agent, in addition to the above-mentioned ultra-high purification of monomers and solvents, a method in which the polymerization temperature and the monomer conversion rate are controlled during the polymerization process can be mentioned.

[0100] In terms of inhibiting the growth reaction or chain transfer, the lower the polymerization temperature, the better. However, in terms of productivity, the polymerization temperature should preferably be at a temperature at which living anion polymerization proceeds sufficiently, i.e., preferably 0°C or higher, but 80°C or lower. However, it should more preferably be 50°C or higher, but 75°C or lower.

[0101] Furthermore, the conversion rate of the total monomer should be less than 99 mass%, and during the modification process mentioned later, this should then be reacted with the modifier. By adding the modifier at a stage where monomers still remain in the polymerization vessel, i.e., by reacting the growing polymer chain and the modifier while the monomers are not yet completely consumed, the formation of polymers whose ends have not been modified, as well as other side reactions, can be reduced. Further preferably, the monomer conversion rate is 98 mass% or less.

[0102] The modified conjugated diene polymer composition (rubber component A) and the later-mentioned rubber component B constituting the modified conjugated diene polymer composition according to this embodiment are each a modified conjugated diene polymer composition, wherein the amount of the bonded conjugated diene polymer in the modified conjugated diene polymer composition including the above-mentioned components constituting the modified conjugated diene polymer composition according to this embodiment is preferably from 40 mass% to 100 mass%, and more preferably from 55 mass% to 90 mass%.

[0103] The amount of bonded aromatic vinyl in a conjugated diene polymer or in a modified conjugated diene polymer is not particularly limited, but is preferably 0 mass% to 60 mass%, and more preferably 10 mass% to 45 mass%.

[0104] By keeping the amount of bonded conjugated diene and bonded aromatic vinyl within the above-mentioned ranges, a vulcanizate can achieve a tendency to improve its balance between snow performance and wet performance, as well as friction resistance. The amount of bonded aromatic vinyl can be measured by the UV ray absorption of the phenyl group, and from this, the amount of bonded conjugated diene can also be determined. Specifically, this can be measured using the method described in the working examples explained later.

[0105] Rubber component A and the later-mentioned rubber component B are each a modified conjugated diene polymer, and in the conjugated diene polymers and the modified conjugated diene polymers, the vinyl compound content in the conjugated diene bond unit should preferably be 10 mol% to 75 mol%, more preferably 20 mol% to 65 mol%. By keeping the vinyl bond content within the above-mentioned ranges, a vulcanizate can be improved in terms of its balance between snow performance and wet performance, as well as friction resistance.

[0106] When the modified conjugated diene polymer is a copolymer of butadiene and styrene, the amount of bonded vinyl (1,2-bonded amount) in the butadiene bonding unit can be determined by the Hampton method (RR Hampton, Analytical Chemistry, 21, 923 (1949)). Specifically, it is measured by the method described in the working examples explained later. < Modification process >

[0107] Then, after the above-mentioned polymerization process, a modification process is carried out on the conjugated diene polymer, and thereby a modified conjugated diene polymer is obtained.

[0108] The rubber component B, which will be mentioned later, is also a modified conjugated diene polymer, and a modification process can be carried out in the same way.

[0109] In the modification process, the conjugated diene polymer obtained by a method described above and a specific modifier having a linking group that reacts with the active end of the above-mentioned conjugated diene polymer and further having a functional group that has affinity or bonding reactivity with a filler are reacted.

[0110] Preferably, the modification process is carried out immediately after the polymerization process. This tends to yield a modified conjugated diene polymer with a high degree of modification.

[0111] If compounds whose linking groups are monofunctional or bifunctional are used as modifiers, straight-chain “end-modified” diene polymers are obtained, but if compounds whose linking groups are trifunctional or more are used, branched-chain modified diene polymers are obtained.

[0112] A monofunctional or multifunctional compound containing nitrogen and optionally at least one element selected from silicon, tin, phosphorus, oxygen, sulfur, and halogen is used as the modifier. Furthermore, an onium structure can be introduced into the above-mentioned modified conjugated diene polymer by adding and reacting an end-group modifier containing an onium generator. Furthermore, a modifier containing multiple functional groups containing these elements in the molecule, or a modifier containing one functional group containing multiple elements, can also be used.

[0113] A preferred modifier is one that contains a functional group containing little or no active hydrogen, such as a hydroxyl group, a carboxyl group, a primary or secondary amino group, etc. The active hydrogen tends to deactivate the active end group of the conjugated diene polymer. [modifier]

[0114] The modifiers are explained in detail below.

[0115] Examples of nitrogen-containing compounds that can be mentioned include, but are not limited to, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen-containing carbonyl compounds, nitrogen-containing vinyl compounds, nitrogen-containing epoxy compounds, etc.

[0116] Silicon-containing compounds include, but are not limited to, nitrogen-containing alkoxysilicon compounds, etc.

[0117] Examples of tin-containing compounds include, but are not limited to, tin halide compounds, organotin carboxylate compounds, etc.

[0118] Examples of phosphorus-containing compounds include, but are not limited to, phosphite compounds, phosphino compounds, etc.

[0119] Examples of oxygen-containing compounds include, but are not limited to, epoxy compounds, ether compounds, ester compounds, etc.

[0120] Examples of sulfur-containing compounds include, but are not limited to, mercapto group derivatives, thiocarbonyl compounds, isothiocyanates, etc.

[0121] Examples of halogen-containing compounds that can be mentioned include, but are not limited to, the above-mentioned silicon halide compounds, tin halide compounds, etc.

[0122] As the onium-generating agent, there can be mentioned, for example, but not limited to, protected amine compounds capable of forming a primary or secondary amine (ammonium-generating), protected phosphine compounds capable of forming hydrophosphine (phosphonium-generating), hydroxyl groups, compounds capable of forming thiols (oxonium, sulfonium-generating), etc., and it is preferable to use an end-modifying agent in which functional groups capable of bonding with the onium-generating agent and the above-mentioned modified conjugated diene polymer are used.

[0123] As the functional group used to bond with the above-mentioned modified conjugated diene polymer, carbonyl groups (ketone, ester, etc.), unsaturated groups such as vinyl groups, epoxy groups, silicon halide groups, alkoxysilicon groups, etc. can be mentioned.

[0124] The modifier is a compound having a nitrogen-containing functional group, and as such compounds having a nitrogen-containing functional group, there can be mentioned amine compounds preferably without active oxygen, for example, tertiary amines, protected amine compounds in which the above-mentioned active oxygen is substituted with a protecting group, and imine compounds which can be represented by a general formula -N=C.

[0125] Examples of the isocyanate compounds among the nitrogen-containing compounds serving as modifiers include, but are not limited to, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, polymer type diphenylmethane diisocyanate (C-MDI), phenyl isocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, 1,3,5-benzene triisocyanate, etc.

[0126] Examples of the nitrogen-containing isocyanuric acid derivatives serving as modifiers include, but are not limited to, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, 1,3,5-tris(3-triethoxysilylpropyl)isocyanurate, 1,3,5-tri(oxiran-2-yl)-1,3,5-triazinan-2,4,6-trione, 1,3,5-tris(isocyanatomethyl)-1,3,5-triazinan-2,4,6-trione, 1,3,5-trivinyl-1,3,5-triazinan-2,4,6-trione, etc.

[0127] Examples of the nitrogen-containing carbonyl compounds serving as modifiers include, but are not limited to, 1,3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3-(2-methoxyethyl)-2-imidazolidinone, N-methyl-2-pyrrolidone, N-methyl-2-piperidone, N-methyl-2-quinolone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, methyl 2-pyridyl ketone, methyl 4-pyridyl ketone, propyl 2-pyridyl ketone, di-4-pyridyl ketone, 2-benzoylpyridine, N,N,N',N'-tetramethylurea, N,N-dimethyl-N',N'-diphenylurea, Methyl N,N-diethylcarbamate, N,N-diethylacetamide, N,N-dimethyl-N',N'-dimethylaminoacetamide, N,N-dimethylpicolinic acid amide, N,N-dimethylisonicotinic acid amide, etc.

[0128] Examples of the nitrogen-containing vinyl compounds serving as modifiers include, but are not limited to, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-methylmaleimide, N-methylphthalimide, N,N-bistrimethylsilylacrylamide, morpholinoacrylamide, 3-(2-dimethylaminoethyl)styrene, (dimethylamino)dimethyl-4-vinylphenylsilane, 4,4'-vinylidenebis(N,N-dimethylaniline), 4,4'-vinylidenebis(N,N-diethylaniline), 1,1-bis(4-morpholino)phenyl)ethylene, 1-phenyl-1-(4-N,N-dimethylaminophenyl)ethylene, etc.

[0129] Examples of nitrogen-containing epoxy compounds serving as modifiers include, but are not limited to, hydrocarbon compounds containing an epoxy group(s) bonded to an amino group, which may also contain an epoxy group bonded to an ether group. Examples of these include compounds that can be represented by the general formula (4).

[0130] In the above formula (4), R represents a di- or polyvalent hydrocarbon group, or a di- or polyvalent organic group containing at least one kind of polar group selected from a group consisting of polar groups containing oxygen such as ether, epoxy, ketone, etc., polar groups containing sulfur such as thioether, thioketone, etc., polar groups containing nitrogen such as tertiary amino groups, imino groups, etc.

[0131] A di- or polyvalent hydrocarbon group can be a saturated or unsaturated straight-chain, branched-chain, or cyclic hydrocarbon group, and can include alkylene groups, alkenylene groups, phenylene groups, etc. Preferably, it is a hydrocarbon group having 1 to 20 carbon atoms. Examples include methylene, ethylene, butylene, cyclohexylene, 1,3-bis(methylene)cyclohexane, 1,3-bis(ethylene)cyclohexane, o-, m-, p-phenylene, m-, p-xylene, bis(phenylene)methane, etc.

[0132] In the above formula (4), R 1 , R 4 a hydrocarbon group having 1 to 10 carbon atoms, and R 1 , R 4 can be identical or different.

[0133] R 2 , R 5 represent hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R 2 , R 5 can be identical or different.

[0134] R 3 represents a hydrocarbon group having 1 to 10 carbon atoms, or has a structure represented by the formula (5) below.

[0135] R 1 , R 2 , R 3 can be connected to each other to form a ring structure.

[0136] Furthermore, if R 3 is a hydrocarbon group, it can be bonded to R to form a ring structure. If the above-mentioned ring structure is formed, a structure is also possible in which N and R, which are bonded to R 3 are connected, are directly connected.

[0137] In the above formula (4), n is an integer 1 or greater, and m is 0 or an integer 1 or greater.

[0138] In the above formula (5), R 1 , R 2 just like R 1 , R 2 the above formula (4), and R 1 , R 2can be identical or different.

[0139] As one of the nitrogen-containing epoxy compounds serving as a modifier, it is preferably one which has an epoxy group-containing hydrocarbon group, more preferably one which has a glycidyl group-containing hydrocarbon group.

[0140] As a hydrocarbon group containing an epoxy group bonded to the amino group or ether group, a glycidylamino group, a diglycidylamino group, or a glycidoxy group can be mentioned. Another preferred molecular structure is an epoxy group-containing compound each having a glycidylamino group or a diglycidylamino group and a glycidoxy group, and for this, compounds represented by the general formula (6) below can be mentioned.

[0141] In the above formula (6), R is defined in the same way as R in the above formula (4), and R 6 represents a hydrocarbon group having 1 to 10 carbon atoms, or has a structure represented by the formula (7) below.

[0142] Is R 6 a hydrocarbon group, it can be linked to R to form a ring structure, and in this case, a structure is possible in which N and R, which are attached to R 6 are connected, are directly connected.

[0143] In the above formula (6), n is an integer 1 or greater, and m is 0 or an integer 1 or greater.

[0144] As one of the nitrogen-containing epoxy compounds serving as a modifier, a compound which has 1 or more diglycidylamino groups in the molecule, and more preferably which has 1 or more glycidoxy groups, is preferably suitable.

[0145] Examples of the nitrogen-containing epoxy compounds serving as modifiers include, but are not limited to, N,N-diglycidyl-4-glycidoxyaniline, 1-N,N-diglycidylaminomethyl-4-glycidoxycyclohexane, 4-(4-glycidoxyphenyl)-(N,N-diglycidyl)aniline, 4-(4-glycidoxyphenoxy)-(N,N-diglycidyl)aniline, 4-(4-glycidoxybenzyl)-(N,N-diglycidyl)aniline, 4-(N,N'-diglycidyl-2-piperazinyl)glycidoxybenzene, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylenediamine, 4,4-methylene-bis(N,N-diglycidylaniline), 1,4-bis(N,N-diglycidylamino)cyclohexane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, 4,4'-bis(diglycidylamino)benzophenone, 4-(4-glycidylpiperazinyl)-(N,N-diglycidyl)aniline, 2-[2-(N,N-diglycidylamino)ethyl]-1-glycidylpyrrolidine, N, N-diglycidylaniline, 4,4'-diglycidyldibenzylmethylamine, N,N-diglycidylaniline, N,N-diglycidylorthotoluidine, N,N-diglycidylaminomethylcyclohexane etc. can be mentioned.

[0146] Particularly suitable examples thereof are N,N-diglycidyl-4-glycidoxyaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0147] Examples of silicon halide compounds used as modifiers include, but are not limited to, tris(dimethylamino)chlorosilane.

[0148] Examples of the alkoxysilicon compounds having nitrogen-containing groups serving as modifiers include, but are not limited to, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-morpholinopropyltrimethoxysilane, 3-piperidinopropyltriethoxysilane, 3-hexamethyleneiminopropylmethyldiethoxysilane, 3-(4-methyl-1-piperazino)propyltriethoxysilane, 1-[3-(triethoxysilyl)propyl]-3-methylhexahydropyrimidine, 3-(4-trimethylsilyl-1-piperazino)propyltriethoxysilane, 3-(3-triethylsilyl-1-imidazolidinyl)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-hexahydropyrimidinyl)propyltrimethoxysilane, 3-Dimethylamino-2-(dimethylaminomethyl)propyltrimethoxysilane, Bis(3-dimethoxymethylsilylpropyl)-N-methylamine, Bis(3-trimethoxysilylpropyl)-N-methylamine, Bis(3-triethoxysilylpropyl)methylamine, Tris(trimethoxysilyl)amine, Tris(3-trimethoxysilylpropyl)amine, N,N,N',N'-Tetra(3-trimethoxysilylpropyl)ethylenediamine,3-Isocyanatopropyltrimethoxysilan, 3-Cyanopropyltrimethoxysilan, 2,2-Dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentan, 2,2-Diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentan, 2,2-Dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexan, 2,2-Dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentan, 2,2-Dimethoxy-1-phenyl-1-aza-2-silacyclopentan, 2,2-Diethoxy-1-butyl-1-aza-2-silacyclopentan, 2,2-Dimethoxy-1-methyl-1-aza-2-silacyclopentan, 2,2-Dimethoxy-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silacyclooctan, 2,2-Dimethoxy-8-(N,N-diethylamino)methyl-1,6-dioxa-2-silacyclooctan etc. genannt werden.,

[0149] As examples of the compounds which have an unsaturated bond and a protected amine in the molecule, and which are the protected amine compounds which can form primary or secondary amines serving as modifiers, there may be mentioned, for example, but are not limited to, 4,4'-vinylidenebis[N,N-bis(trimethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(triethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(t-butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(triethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(triethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(t-butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(t-butyldimethylsilyl)aniline], 1-[4-N,N-bis(trimethylsilyl)aminophenyl]-1-[4-N-methyl-N-(trimethylsilyl)aminophenyl]ethylene, 1-[4-N,N-bis(trimethylsilyl)aminophenyl]-1-[4-N,N-dimethylaminophenyl]ethylene etc. can be mentioned.

[0150] As examples of the compounds which have alkoxysilane and protected amine in the molecule and which are the protected amine compounds which can form primary or secondary amines serving as modifiers, there may be mentioned, but are not limited to, N,N-bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldimethoxysilane, N,N-bis(trimethylsilyl)aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethylmethyldiethoxysilane, N,N-bis(triethylsilyl)aminopropylmethyldiethoxysilane, 3-(4-trimethylsilyl-1-piperazino)propyltriethoxysilane, 3-(3-Triethylsilyl-1-imidazolidinyl)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-hexahydropyrimidinyl)propyltrimethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-Diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-Dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane, 2,2-Dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, 2,2-Dimethoxy-1-phenyl-1-aza-2-silacyclopentane, 2,2-Diethoxy-1-butyl-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-methyl-1-aza-2-silacyclopentane etc. can be mentioned.,

[0151] Examples of sulfur-containing compounds serving as modifiers include, but are not limited to, protected thiol compounds such as N,N-ethyldiethyldithiocarbamate, phenyl isothiocyanate, phenyl 1,4-diisothiocyanate, hexamethylene diisothiocyanate, butyl isothiocyanate, etc.

[0152] A modifier should preferably be a compound having a silicon-containing functional group, and this silicon-containing functional group should preferably be a group having an alkoxysilyl group or a silanol group.

[0153] The alkoxysilyl group of the modifier tends to react, for example, with the active ends of the conjugated diene polymer, separating the alkoxylithium and forming a bond between the end of the conjugated diene polymer chain and the silicon of the modifier's residual group. If the number of SiOR reduced by the reaction is subtracted from the total number of SiOR in a molecule of the modifier, the number of alkoxysilyl groups of the residual group of the modifier is obtained. In addition, the azasilacycle group of the modifier forms an >N-Li bond as well as a bond between the end of the conjugated diene polymer and the silicon of the residual group of the modifier. The >N-Li bond tends to easily convert to >NH and LiOH during completion, due to water, among other things. Furthermore, the unreacted alkoxysilyl group of the modifier tends to easily convert to >NH and LiOH during completion, among other things.to become a silanol (Si-OH group) because of the water.

[0154] If a modifier containing three alkoxy groups per silicon atom is used in the modification process, i.e., if three moles of the active end group of the conjugated diene polymer are reacted with one mole of a trialkoxysilane group, the reaction will occur up to two moles of the conjugated diene polymer, but one mole of the alkoxy group will tend to remain unreacted. This can be determined by the fact that one mole of the conjugated diene polymer remains unreacted and remains as an unreacted polymer. Furthermore, by reacting the alkoxy group in large quantities, it is possible to inhibit a significant change in polymer viscosity caused by the condensation reaction during production and storage. Preferably, a modifier containing one alkoxysilyl group per silicon atom should be used.

[0155] The reaction temperature during the modification process is preferably similar to that used during the polymerization of the conjugated diene polymer, especially a temperature that has not been increased after the polymerization. Preferably, this temperature is between 0°C and 120°C, and even more preferably between 50°C and 100°C.

[0156] The reaction time of the modification process is preferably 10 seconds or longer, and more preferably 30 seconds or longer.

[0157] Any mixing method, such as mechanical mixing, mixing with a static mixer, etc., can be used for mixing the conjugated diene polymer and the modifier during the modification process. If the polymerization process is continuous, the modification process should preferably also be continuous. A tank with a stirrer, tubes, etc., can be used as a reactor for the modification process. The modifier can also be diluted with an inert solvent and continuously fed into the reactor.

[0158] As a modifier, a compound which can be represented by the general formula (8) below is suitable, with the proviso that the compound contains nitrogen.

[0159] In formula (8), R 12 to R 14each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, R 15 to R 18 and R 20 each independently represents an alkyl group having 1 to 20 carbon atoms, R 19 and R 22 independently represent an alkylene group having 1 to 20 carbon atoms, and R 21 represents an alkyl group or a trialkylsilyl group having 1 to 20 carbon atoms.

[0160] The letter m stands for an integer from 1 to 3, and p stands for 1 or 2.

[0161] If these are present multiple times, R 12 to R 22 , m, and p independently of each other.

[0162] The i is an integer from 0 to 6, j is an integer from 0 to 6, k is an integer from 0 to 6, where (i + j + k) is an integer from 1 to 10.

[0163] A represents a single bond, a hydrocarbon group having 1 to 20 carbon atoms, or at least one kind of atoms selected from the group consisting of an oxygen atom, nitrogen atom, silicon atom, sulfur atom, phosphorus atom and an organic group without active hydrogen.

[0164] A hydrocarbon group that can be represented by A includes a hydrocarbon group that is saturated, unsaturated, aliphatic, or aromatic. An organic group without active hydrogen is an organic group that deactivates the active ends of the conjugated diene polymer. This organic group is an organic group that does not have a functional group with active hydrogen such as a hydroxyl group (-OH), secondary amino group (>NH), primary amino group (-NH2), or sulfhydryl group (-SH). If (i + j + k) = 1, A can be omitted.

[0165] In formula (8), A preferably represents one of the compounds which can be represented by one of the general formulas (9) to (12).

[0166] In the above formula (9), B 1 a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer from 1 to 10, where B 1 , if it exists multiple times, each is independent.

[0167] In the above formula (10), B 2 a single bond or a hydrocarbon group with 1 to 20 carbon atoms, B 3 an alkyl group having 1 to 20 carbon atoms, and a represents an integer from 1 to 10, where B 2 and B 3 , if they exist multiple times, are each independent.

[0168] In the above formula (11), B 4a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer from 1 to 10, where B 4 , if it exists multiple times, each is independent.

[0169] In the above formula (12), B 5 a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer from 1 to 10, where B 5 , if it exists multiple times, each is independent.

[0170] Since in the above-mentioned formula (8), the letter A preferably represents one of the compounds which can be represented by any of the above-mentioned formulas (9) to (12), a modified conjugated diene polymer with even better performances can be obtained.

[0171] As modifiers of the above-mentioned formula (8) in which (i + j + k) is 1 to 2, including the modifiers already mentioned above, but not limited to, for example, 3-dimethoxymethylsilylpropyldimethylamine (monofunctional), 3-trimethoxysilylpropyldimethylamine (bifunctional), bis(3-trimethoxysilylpropyl)methylamine (tetrafunctional), bis(3-dimethoxymethylsilylpropyl)methylamine (bifunctional), (3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]ethylamine (tetrafunctional), [3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)methylamine (tetrafunctional), bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]methylamine (tetrafunctional), Bis(3-triethoxysilylpropyl)ethylamine (tetrafunctional), 1-(3-triethoxysilylpropyl)-2,2-diethoxy-1-aza-2-silacyclopentane (tetrafunctional), 1-(3-dimethoxymethylsilylpropyl)-2,2-dimethoxy-1-aza-2-silacyclopentane (trifunctional), [3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-(3-diethoxyethylsilylpropyl)methylamin (trifunktionell), Bis[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]methylamin (tetrafunktionell), (3-Trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]methylamin (trifunktionell) genannt werden.,

[0172] As multifunctional compounds, each of which is a modifier of the above-mentioned formula (8) in which (i + j + k) is 3 or greater, and which is a modifier in which A in the above-mentioned formula (8) can be represented by the above-mentioned formula (9), there can be mentioned, but are not limited to, tris(3-trimethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)amine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tris(3-ethoxysilylpropyl)amine, Bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]amine, bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)amine, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]amine, Tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, Tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propandiamin, Bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-1,3-propandiamin, Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-(3-trimethoxysilylpropyl)-1,3-propandiamin, Tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclo)pentan)propyl]-1,3-propandiamin, Tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-propandiamin, Bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-propandiamin, Bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-Sila-2-azacyclopentan)propyl]-1,3-propandiamin, Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentan) propyl]-1,3-propandiamin, Tetrakis(3-triethoxysilylpropyl)-1,3-propandiamin, Tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-1,3-propandiamin, Bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-1,3-propandiamin, Tris[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-(3-triethoxysilylpropyl)-1,3-propandiamin, Tetrakis[3- (2,2-Diethoxy-1-aza-2-silacyclopentan)propyl]-1,3-propandiamin, Tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-propandiamin, Bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-[3-(1-Ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-propandiamin, Bis[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-propandiamin, Tris[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-propandiamin, Tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexan, Tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-1,3-bisaminomethylcyclohexan, Bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-1,3-bisaminomethylcyclohexan, Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexan, Tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-1,3-propandiamin, Tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-bisaminomethylcyclohexan, Bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-bisaminomethylcyclohexan, Bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila -2-azacyclopentan)propyl]-1,3-bisaminomethylcyclohexan, Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-[3-(1-methoxy-2-Trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-bisaminomethylcyclohexan, Tetrakis(3-triethoxysilylpropyl)-1,3-propandiamin,Tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-1,3-bisaminomethylcyclohexan, Bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-1,3-bisaminomethylcyclohexan, Tris[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-(3-triethoxysilylpropyl)-1,3-propandiamin, Tetrakis[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-1,3-propandiamin, Tris(3-triethoxysilyl)propyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-bisaminomethylcyclohexan, Bis(3-triethoxysilylpropyl)-[3-(2,2-Diethoxy-1-aza-2-silacyclopentan)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-bisaminomethylcyclohexan, Bis[3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-Bisaminomethylcyclohexan, Tris [3-(2,2-diethoxy-1-aza-2-silacyclopentan)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]-1,3-bisaminomethylcyclohexan,Tetrakis(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, Pentakis(3-trimethoxysilylpropyl)diethylenetriamine.

[0173] As modifiers in which A of the above-mentioned formula (8) can be represented by the above-mentioned formula (10), there can be used, for example, but not limited to, tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, tris(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine, Bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, N 1 ,N 1 '-(Propane-1,3-diyl)bis(N 1 -methyl-N 3 ,N 3-bis(3-(trimethoxysilyl)propyl)-1,3-propandiamin), N 1 -(3-(Bis(3-(trimethoxysilyl)propyl)amino)propyl)-N 1 -methyl-N 3 -(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N 3 -(3-(trimethoxysilyl)propyl)-1,3-propandiamin genannt werden.

[0174] As modifiers in which A of the above-mentioned formula (8) can be represented by the formula (11), there can be used, for example, but not limited to, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)silane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]silane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, (3-Trimethoxysilyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, Bis[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, Bis(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, bis[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-bis(3-trimethoxysilylpropyl)silane, bis(3-trimethoxysilylpropyl)-bis[3-(1-methoxy-2-methyl-1-sila-2-azacyclopentane)propyl]silane become.,

[0175] As modifiers in which A of the above-mentioned formula (8) can be represented by the above-mentioned formula (12), there may be mentioned, for example, but not limited to, 3-tris[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-(2,2-dimethoxy-1-aza-2-silacyclopentane)propane, 3-tris[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-trimethoxysilylpropane.

[0176] As modifiers in which A of the above-mentioned formula (8) represents an organic group which has an oxygen atom but no active hydrogen, there may be mentioned, for example, but not limited to, (3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl] ether (tetrafunctional), 3,4,5-tris(3-trimethoxysilyl)propyl)cyclohexyl-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl] ether (octafunctional).

[0177] As modifiers in which A of the above-mentioned formula (8) represents an organic group which has a phosphorus atom but no active hydrogen, there may be mentioned, for example, but not limited to, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]phosphate, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)phosphate, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]phosphate.

[0178] In the above-mentioned formula (8), A is preferably represented by the above-mentioned formula (9) or the above-mentioned formula (10), and k is 0. This tends to make a modifier more readily available, and when a modified conjugated diene polymer is processed into vulcanizate, it tends to exhibit even more excellent friction resistance and even lower hysteresis loss.

[0179] Such modifiers may include, but are not limited to, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)methyl-1,3-propanediamine, Bis[3-(2,2-dimethoxy-1-aza-2-silacyclopenta)-propyl]-(3-tris methoxysilylpropyl)-methyl-1,3-propanediamine.

[0180] In the above-mentioned formula (8), A is preferably represented by the formula (9) or formula (10), k is 0, and in the formula (9) or formula (10), a is an integer of 2 to 10. When a modified conjugated diene polymer prepared by using such a modifier is used, a vulcanizate tends to have even more excellent friction resistance and even lower hysteresis loss.

[0181] Such modifiers may include, but are not limited to, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, N 1 -(3-(Bis(3-(trimethoxysilyl)propyl)amino)propyl)-N 1 -methyl-N 3 -(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N 3 -(3-(trimethoxysilyl)propyl)-1,3-propanediamine.

[0182] This amount of the compound represented by formula (8) to be added as a modifier can preferably be regulated so that a reaction can take place in a desired stoichiometric ratio between the number of moles of the polymerization initiator and the number of moles of the modifier, and thereby the desired degree of branching of the modified conjugated diene polymer can tend to be achieved.

[0183] The specific number of moles of the polymerization initiator relative to the number of moles of the modifier is 1.0 times or more, and more preferably 2.0 times or more. In this case, in formula (8), the number of functional groups of the modifier ((m-1) × i + p × j + k) is preferably an integer from 1 to 10, and more preferably an integer from 2 to 10. < Glass transition temperature of the modified conjugated diene polymer (rubber component A) >

[0184] The glass transition temperature of the modified conjugated diene polymer (rubber component A) is -35°C or higher. Preferably, this is -30°C or higher, more preferably -25°C or higher.

[0185] The glass transition temperature of the modified conjugated diene polymer (rubber component A) can be regulated within the above-mentioned numerical range by controlling the above-mentioned microstructure, that is, the amount of vinyl aromatic compound or the amount of vinyl bond in the above-mentioned modified conjugated diene polymer can be controlled.

[0186] By remaining within the above-mentioned ranges, a vulcanizate with an even improved balance between snow performance and wet performance can be obtained.

[0187] The glass transition temperature is taken as the peak (inflection point) of a DSC derivative curve obtained from a DSC curve recorded in accordance with ISO 22768:2006 while increasing the temperature within a specific range. Specifically, it can be measured by the method described in the later working examples. Although the glass transition temperature of the modified conjugated diene polymer (rubber component A) has no specific upper limit, it is preferably -10°C or lower. By keeping it within the above ranges, the balance between snow performance and wet performance tends to be improved. < Addition of stabilizers, extension oils, etc. for rubber >

[0188] A rubber stabilizer is preferably added to a modified conjugated diene polymer which is a component of the modified conjugated diene polymer composition according to this embodiment in order to prevent gel formation after polymerization and to improve stability during processing.

[0189] In this case, the rubber component A belongs to the modified conjugated diene polymers, and if the rubber component B is a modified conjugated diene polymer, it also belongs to the group.

[0190] As the stabilizer for rubber, known stabilizers can be used, and antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol)propionate, 2-methyl-4,6-bis[(octylthio)methyl]phenol, etc. can be mentioned, but are not limited to.

[0191] To improve the processability of a modified conjugated diene polymer, extension oil can be added to the modified conjugated diene polymer if required.

[0192] As a method for adding the extension oil to a modified conjugated diene polymer, for example, a method in which an extension oil is added to this polymer solution, mixed, and then the solvent is removed from the oil-extended copolymer solution is suitable, but is not limited to this.

[0193] As the time at which the extension oil is added, for example, a time after the modification process but before the mixing of the polymerization solution, that is, after the modification process of the modified conjugated diene polymer of the rubber component A (and the rubber component B), a time before the mixing of the rubber component A and the rubber component B, or a time after the mixing of the two polymerization solutions, that is, after the modification process of the rubber component A (and the rubber component B) and after the two polymerization solutions of the rubber component A and the rubber component B have been mixed, can be mentioned, without being limited to the following times.When the extension oil is mixed, the viscosity of the polymerization solution decreases and the polymerization solutions can be mixed more easily, so from this point of view, the time “after the modification process but before mixing the two polymerization solutions” is preferred.

[0194] Examples of extension oils include aromatic oil, naphthenic oil, paraffin oil, etc. Among these, aromatic replacement oils containing 3% or less by mass of a polycyclic aromatic (PCA) component according to the IP 346 method are preferred in terms of environmental safety, oil bleeding prevention, and wet adhesion properties.

[0195] Aromatic replacement oils that can be mentioned are TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solvate) and RAE (Residual Aromatic Extracts), which are mentioned in “Kautschuk Gummi Kunststoffe 52(12)799 (1999)”.

[0196] The amount of extension oil added is not limited, but it is preferably 5 parts by mass to 60 parts by mass based on 100 parts by mass of the modified conjugated diene polymer. < Degree of modification >

[0197] In the modified conjugated diene polymer (rubber component A), the degree of modification relative to the total content of conjugated diene polymer is 50 mass% or higher, preferably 60 mass% or higher, and more preferably 75 mass% or higher.

[0198] A modification degree of 50 mass% or higher improves the reactivity of the vulcanizate with the silica filler, and thus tends to improve the dispersibility of the silica in the vulcanizate. As a result, the peak of the temperature distribution of viscoelasticity becomes sharper, and wet performance tends to improve.

[0199] The degree of modification is the content, expressed as mass%, of the polymer component having a specific functional group with affinity or binding reactivity to the silica, which is a filler, in the polymer molecule with respect to the total amount of the conjugated diene polymer.

[0200] As a polymer component having a specific functional group with affinity or bonding reactivity to silica, which is a filler, polymers having functional groups containing a nitrogen atom are preferable. Even more preferable are modified conjugated diene polymers having these functional groups at the polymer terminals. For example, a polymer having a functional group bonded to a nitrogen atom at the polymerization initiation terminal and / or a modified conjugated diene polymer having a functional group bonded to a nitrogen atom at the polymerization termination terminal can be mentioned.

[0201] The degree of modification can be measured by chromatography, which can separate the modified component containing a functional group from the unmodified component. One chromatography method is one in which a gel permeation chromatography column is used, in which a polar substance such as silica or the like that adsorbs a specific functional group is packed as a packing material, and in which quantitative determination is performed using an internal standard for non-adsorbable components for comparison.

[0202] Specifically, this degree of modification can be determined by calculating the difference between the chromatogram measured with the polyethylene gel column and the chromatogram measured with the silica column of the sample solution containing the measurement sample and the low molecular weight internal standard polystyrene, and measuring the adsorption amount on the silica column.

[0203] The degree of modification can be measured using the method described in the following example.

[0204] As a method by which the modification degree of the modified conjugated diene polymer can be controlled to 50 mass% or higher, for example, a method in which the amount of modifier is adjusted or in which the conditions of the reaction process are adjusted can be mentioned.

[0205] Here, the rubber component A constituting the modified conjugated diene polymer composition according to this embodiment belongs to the modified conjugated diene polymers, and the rubber component B, which will be mentioned later, is a modified conjugated diene polymer, and the rubber component B also belongs to the modified conjugated diene polymer. For example, a method in which polymerization is carried out using an organolithium compound containing at least one nitrogen atom in the molecule as a polymerization initiator, a method in which monomers containing at least one nitrogen atom in the molecule are copolymerized, or a method in which the polymerization conditions are controlled so as not to excessively accelerate the chain transfer reaction, for example, by lowering the polymerization temperature, can be mentioned.

[0206] The upper limit of the degree of modification is not particularly restricted, but it is preferably 95% by mass or less. Maintaining this range can inhibit the cohesion of the fillers in the vulcanizate, and therefore processability tends to be excellent.

[0207] As a method by which the modification degree of the modified conjugated diene polymer can be inhibited to 95 mass% or less, there can be mentioned a method in which the addition amount of the modifier is reduced (it is regulated so that the number of moles of the functional group to which the modifier can bond is less than the number of moles of the polymer chain) and a method in which the addition amount of the later-mentioned organolithium compound serving as a polymerization initiator which contains at least one nitrogen atom in the molecule is reduced (organolithium containing a nitrogen atom and organolithium not containing a nitrogen atom are used together as a polymerization initiator). < weight-average molecular weight >

[0208] A modified conjugated diene polymer (rubber component A) has a weight-average molecular weight of 20 × 10 4up to 300 × 10 4 , preferably 30 × 10 4 up to 270 × 10 4 , more preferably 40 × 10 4 up to 250 × 10 4 .

[0209] Because its weight-average molecular weight is 20 × 10 4 or more, the interweaving density between the molecular chains increases, thus tending to improve the breaking strength, and when processed into vulcanizate, it tends to obtain excellent friction resistance.

[0210] Because its weight-average molecular weight is 300 × 10 4 or less, the dispersibility of the filler(s) when processed into the vulcanizate is excellent, and therefore excellent wet performance tends to be obtained.

[0211] The weight-average molecular weight of the modified conjugated diene polymer can be controlled by adjusting the molecular weight of the conjugated diene polymer by selecting an appropriate ratio between the amounts of polymerization initiator and monomer to be used, or by adjusting the type and amount of the modifier.

[0212] Furthermore, in the present specification, the term "molecular weight" refers to a standard polystyrene equivalent molecular weight obtained by GPC (gel permeation chromatography). The number-average molecular weight, weight-average molecular weight, and molecular weight distribution can each be measured by a method mentioned in the following working examples. < Molecular weight distribution >

[0213] A modified conjugated diene polymer (rubber component A) has a molecular weight distribution Mw / Mn, which is expressed as the ratio of the number-average molecular weight (Mn) to the weight-average molecular weight (Mw), of 1.6 to 4.0. A modified conjugated diene polymer with a molecular weight distribution in this range tends to have better processability into a vulcanizate than a polymer with a similar molecular weight and degree of modification. This value is preferably between 1.8 and 3.0, and more preferably between 1.9 and 2.5.

[0214] A modified conjugated diene polymer having such a molecular weight distribution can preferably be obtained by continuous polymerization.

[0215] With this molecular weight distribution, the GPC molecular weight curve preferably exhibits a single peak (monomodal) shape, or, if there are multiple peaks, a trapezoidal or double peak shape. The double peak shape is one in which the height of the lowest point between the peaks is 50% or higher relative to the height of the two peaks. A modified conjugated diene polymer with this molecular weight distribution tends to exhibit excellent processability into a vulcanizate.

[0216] The molecular weight distribution can be controlled within the above-mentioned ranges by controlling the molecular weight of the conjugated diene polymer by selecting an appropriate ratio between the amounts of polymerization initiator and monomer to be used, or by adjusting the type and amount of the modifier and the polymerization temperature. < Degree of modification of the low molecular weight component >

[0217] In the modified conjugated diene polymer composition (rubber component A), the degree of modification of the component (the low molecular weight component) having a molecular weight equal to half the molecular weight at the peak tip of the GPC curve, or, if multiple peaks are present, at the smallest peak tip, should preferably be half the degree of modification of the total amount of the conjugated diene polymer or more.

[0218] When the modification degree of the low-molecular-weight component of the above-mentioned modified conjugated diene polymer (rubber component A) is within the above-mentioned ranges, its processability is improved. In particular, the effect of the mixer's torque on it during kneading with the filler is improved, so that the miscibility of the rubber component A and the rubber component B with the filler tends to improve. This improves the dispersibility of the filler, and thus the wet performance tends to improve, thus enhancing the balance between the snow performance and the wet performance of the above-mentioned modified conjugated diene polymer composition.

[0219] In addition to the above-mentioned finding that the degrees of modification vary depending on the molecular weight range, the inventors discovered the following mechanisms of how the torque is transmitted during kneading of the polymer and the filler.

[0220] First, considering the degree of modification relative to the total proportion of conjugated diene polymer, the rate of increase of the torque during kneading with a filler is faster for a polymer with a high degree of modification (degree of modification ≥ 50%) than for a polymer with a low degree of modification, provided that the conditions such as the Mooney viscosity, the microstructure, the modifier used, the kneading conditions, etc. of the polymer are the same. However, the time until the torque reaches the maximum value is always almost the same, even if the overall degree of modification has changed, since the maximum value of the achievable torque becomes correspondingly higher.Since the degree of modification of an overall polymer influences both the maximum value of the torque and the rate of increase of the torque, the length of time until the maximum value of the torque is reached is hardly affected, even if the overall degree of modification has changed.

[0221] On the other hand, considering the degree of modification of the above-mentioned low molecular weight component, the rate of increase of the torque when kneading the polymer with a filler becomes slower when the degree of modification of the above-mentioned low molecular weight component is low compared to the degree of modification based on the total content of conjugated diene polymer, and the rate of increase of the torque becomes faster when the degree of modification of the above-mentioned low molecular weight component is higher compared to the degree of modification based on the total content of conjugated diene polymer.

[0222] On the other hand, since the maximum torque value is determined depending on the degree of modification relative to the total amount of conjugated diene polymer, it does not change depending on the degree of modification of the low-molecular-weight component. Therefore, the time required to reach the maximum torque becomes shorter the higher the degree of modification of the low-molecular-weight component. Therefore, the time required to reach the maximum torque can be controlled not depending on the degree of modification of the total amount of conjugated diene polymer, but rather depending on the degree of modification of the low-molecular-weight component relative to the degree of modification of the total amount of conjugated diene polymer.

[0223] Specifically, by adjusting the above-mentioned modification degree of the low-molecular-weight component to half or more of the modification degree of the total amount of conjugated diene polymer, processability can be improved, especially the effect of the mixer's torque during kneading with the filler. This can tend to improve the miscibility of the rubber component A, the rubber component B, and the fillers in a shorter time than before. This improves the processability and dispersibility of the filler, and thus tends to improve wet performance. < Nitrogen content >

[0224] The nitrogen content of a modified conjugated diene polymer which is the rubber component A is preferably 25 ppm by mass or more, more preferably 40 ppm by mass or more, and further preferably 60 ppm by mass or more based on the total content of this modified conjugated diene polymer.

[0225] When the nitrogen content is within the above-mentioned ranges, the modified conjugated diene polymer composition according to this embodiment is vulcanized, it tends to exhibit an excellent balance between low hysteresis loss and wet skid resistance. However, in view of processability into a vulcanizate and filler dispersibility, the content should preferably be 250 ppm by mass or less, more preferably 150 ppm by mass or less, and further preferably 100 ppm by mass or less.

[0226] The nitrogen atom content can be measured using the oxidation-combustion chemiluminescence method (JIS-2609: Petroleum and Petroleum Products - Nitrogen Content Analysis Method). The nitrogen atom content can be measured more specifically using the method described in the examples explained later.

[0227] As a method by which the nitrogen content of a modified conjugated diene polymer which is the rubber component A can be adjusted to 25 ppm by mass or higher, methods in which the polymerization initiator, the modifiers, the kind and / or the amount of monomers are regulated can be mentioned, and as examples thereof, a method in which polymerization is carried out using an organolithium compound having at least one nitrogen atom in the molecule as a polymerization initiator, a method in which a modifier having at least one nitrogen atom in the molecule is reacted with a conjugated diene polymer having at least one nitrogen atom obtained by copolymerizing the monomers having at least one nitrogen atom in the molecule can be mentioned. < Shrinkage factor >

[0228] The shrinkage factor (g'), measured by the GPC light scattering measurement method with a viscosity detector (hereinafter, this "GPC light scattering measurement method with a viscosity detector" may also be referred to as "3D GPC measurement"), is an indicator of the number of branches of the modified conjugated diene polymer. For example, as the shrinkage factor (g') decreases, the number of branches of the modified conjugated diene polymer (e.g., the number of branches of the star-shaped high molecular compound (also called the number of arms of the star-shaped high molecular compound)) tends to increase.

[0229] In the case where modified conjugated diene polymers with the same molecular mass are to be compared, the shrinkage factor (g') can be used as an indicator of the degree of branching, since the more branches a modified conjugated diene polymer has, the smaller the shrinkage factor (g') it has.

[0230] The shrinkage factor (g') is measured using a 3D GPC measurement.

[0231] The constant (K, α) of the correlation between the specific viscosity and the molecular weight ([η] = Kmα ([η] : specific viscosity, M : molecular weight) were set to log K = -3.888 and α = 0.771, and a graph representing the relationship between the standard specific viscosity [η]0 and the molecular weight M was constructed.

[0232] As the relationship [η] / [η]0 between the specific viscosity [η] and the specific standard viscosity [η]0, the specific viscosity [η] for the respective molecular weight M of the sample determined by 3D-GPC measurement was calculated against the specific standard viscosity [η]0 for the respective molecular weight M, and the mean value thereof was taken as the shrinkage factor (g').

[0233] Specifically, this can be measured by the method described in the embodiments explained later.

[0234] Furthermore, a preferred embodiment for a modified conjugated diene polymer which is the rubber component A is when the shrinkage factor (g') measured by 3D-GPC is 0.70 or less.

[0235] However, it should preferably be 0.30 or larger, but 0.70 or smaller.

[0236] With such a modified conjugated diene polymer, the viscosity of the rubber composition with the filler becomes significantly lower, and thus the processability becomes quite excellent.

[0237] The shrinkage factor (g') is an indicator of the branching structure of the modified conjugated diene polymer, and a modified conjugated diene polymer with a shrinkage factor (g') of 0.30 to 0.70 is a modified conjugated diene polymer having 4 or more branches per 1 molecule of the modified diene polymer.

[0238] For obtaining a modified conjugated diene polymer having a shrinkage factor (g') in the above-mentioned ranges, for example, a method is effective in which a modifier having 4 or more reaction points against the living active terminals is added at a number of moles one-fourth or less than the total number of moles of the polymerization initiator, thereby obtaining a modified conjugated diene polymer having four or more branches. < Rubber component B >

[0239] A modified conjugated diene polymer composition according to this embodiment contains the rubber component B whose glass transition temperature is -55°C or lower. Preferably, this is -60°C or lower, and more preferably -65°C or lower.

[0240] By containing the above-mentioned rubber component B, the stiffness of the vulcanizate is reduced at low temperatures, and the snow performance is therefore improved.

[0241] Although the glass transition temperature of rubber component B has no specific lower limit, it is preferably -100°C or higher. Setting the glass transition temperature to -100°C or higher tends to improve friction resistance.

[0242] The Tg of rubber component B can be regulated within the above-mentioned numerical range by controlling the above-mentioned microstructure of the polymer, which is the above-mentioned rubber component B, i.e., by adjusting the amount of vinyl aromatic compound or the amount of vinyl bond. Natural rubber can be used as rubber component B, and the values ​​can be regulated within the above-mentioned ranges.

[0243] A modified conjugated diene polymer is used as the above-mentioned rubber component B.

[0244] The rubber component B is a modified conjugated diene polymer selected from a random copolymer of a conjugated diene compound and a vinyl aromatic compound or hydrogenated products thereof, block copolymers of a conjugated diene compound and a vinyl aromatic compound or hydrogenated products thereof.

[0245] As rubber component B, for example, styrene-based elastomers such as styrene-butadiene rubber or a hydrogenated product thereof, styrene-butadiene block copolymer or a hydrogenated product thereof, styrene-isoprene block copolymers or a hydrogenated product thereof can be mentioned.

[0246] In order to improve the balance between snow performance and wet performance, the rubber component B should be a modified conjugated diene polymer having a weight-average molecular weight of 20 × 10 4 up to 300 × 10 4 and has a molecular weight distribution Mw / Mn of 1.6 to 4.0.

[0247] In order to improve the balance between snow performance and wet performance, the above-mentioned rubber component B is a modified conjugated diene polymer in which the degree of modification to the total content of conjugated diene polymer is 50 mass% or higher.

[0248] Furthermore, in view of processability as a vulcanizate, the rubber component B should preferably be a modified conjugated diene polymer in which the degree of modification of the component having a molecular weight corresponding to half of the molecular weight at the peak tip of the gel permeation chromatography (GPC) curve, or, when multiple peaks are present, at the smallest peak tip, is half of the degree of modification of the total amount of the above-mentioned conjugated diene polymer or more.

[0249] The rubber component B is a modified conjugated diene polymer, and the rubber component B can be prepared by the same method as the above-mentioned rubber component A, and the weight-average molecular weight, molecular weight distribution, modification degree, and modification degree of the low molecular weight component of the rubber component B can also be controlled by the same method as the above-mentioned rubber component A. < Fillers >

[0250] A modified conjugated diene polymer composition according to this embodiment contains silica-containing filler.

[0251] The above-mentioned modified conjugated diene polymer composition is preferably a composition containing a total of 100 parts by mass of the above-mentioned rubber component A and the above-mentioned rubber component B and 5 to 150 parts by mass of filler.

[0252] An inorganic silica filler is included as the above-mentioned filler.

[0253] In a modified conjugated diene polymer composition according to this embodiment, by dispersing the inorganic silica filler, the processability into a vulcanizate and the balance between snow performance and wet performance, as well as the friction resistance of the vulcanizate, can tend to be improved.

[0254] The content of fillers should preferably be 5.0 mass parts or more in view of the effects of the fillers when the sum of the rubber component A and the rubber component B is calculated as 100 mass parts, but should be 150 mass parts or less in view of that these fillers can be sufficiently dispersed and that the processability and mechanical stability of the modified conjugated diene polymer composition are sufficiently practical.

[0255] Even when the modified conjugated diene polymer composition according to this embodiment is used as vulcanized rubber applications, for example, for vehicle parts such as tires, cushioning rubbers, etc., shoe soles, etc., an inorganic silica filler is included.

[0256] In addition to the above-mentioned inorganic silica fillers, other fillers that can be used include, but are not limited to, carbon black, metal oxides, metal hydroxides, etc. These can be used individually or in combinations of two or more types.

[0257] The inorganic silica fillers are not particularly limited, and known ones can be used, preferably using solid particles containing SiO2 as a structural unit, and more preferably using solid particles containing SiO2 as the main component of the structural unit. The main component referred to here is a component contained in an inorganic silica filler by 50 mass% or more, preferably 70 mass% or more, and more preferably 80 mass% or more.

[0258] Examples of inorganic silica fillers include, but are not limited to, inorganic fiber materials such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, glass fiber, etc. Further examples include a surface-hydrophobized inorganic silica filler, a mixture of an inorganic silica filler and inorganic filler(s) other than silica filler, etc. Among these, silica and glass fibers are preferred in terms of strength and abrasion resistance, with silica being more preferred. Examples of silica include dry silica, wet silica, synthetic silica, etc. Among these, wet silica is preferred in terms of the balance between the effect of improving fracture properties and wet skid resistance.

[0259] In the modified conjugated diene polymer composition according to this embodiment, in view of obtaining excellent practical friction resistance and fracture property, the specific nitrogen adsorption surface area determined by the BET adsorption method of the inorganic silica filler is preferably 100 m 2 / g up to 300m 2 / g, and more preferably from 170m 2 / g up to 250m 2 / g. If required, an inorganic silica filler with a relatively small specific surface area (for example, a specific surface area of ​​200m 2 / g or smaller) and an inorganic silica filler with a relatively large specific surface area (for example, a specific surface area of ​​200m 2 / g or greater) may be used in combination.

[0260] If an inorganic silica filler with a relatively large specific surface area (e.g. 200m 2 / g or greater) is used, the modified conjugated diene polymers which are the above-mentioned rubber component A and the rubber component B tend to have excellent dispersibility of the silica, and this also tends to enable particularly improvement in friction resistance as well as a high level balance between excellent fracture property and low hysteresis loss to be achieved.

[0261] Carbon black can include, but is not limited to, carbon black in different classes such as SRF, FEF, HAF, ISAF, SAF, etc. Of these, a carbon black is suitable where the specific nitrogen adsorption surface is 50m 2 / g or more, and dibutyl phthalate (DBP) oil absorption of 80ml / 100g or less.

[0262] The carbon black content, based on 100 parts by mass of the total amount of the above-mentioned rubber component A and the above-mentioned rubber component B, is preferably 0.5 parts by mass to 100 parts by mass, more preferably 3.0 parts by mass to 100 parts by mass, and further preferably 5.0 parts by mass to 50 parts by mass. The carbon black content should preferably be 0.5 parts by mass or more in terms of the performance expected from a tire, such as dry grip, electrical conductivity, etc., but 100 parts by mass or less in terms of dispersibility.

[0263] A modified conjugated diene polymer composition according to this embodiment may contain a silane coupling agent.

[0264] This silane coupling agent has a function of enhancing the interaction between the rubbery polymer and the filler, particularly the inorganic filler, and has a group having an affinity or bonding ability to the rubbery polymer and the inorganic silica filler, and is preferably a compound having a sulfur bonding portion and an alkoxysilyl group or a silanol group portion in its molecule.

[0265] Examples of such compounds include bis-[3-(triethoxysilyl)-propyl]tetrasulfide, bis-[3-(triethoxysilyl)-propyl]disulfide, bis-[2-(triethoxysilyl)-ethyl]tetrasulfide.

[0266] The content of the silane coupling agent based on 100 parts by mass of the above-mentioned inorganic filler is preferably from 0.1 parts by mass to 30 parts by mass, more preferably from 0.5 parts by mass to 20 parts by mass, and further preferably from 1.0 parts by mass to 15 parts by mass. When the content of the silane coupling agent is within the above-mentioned ranges, the effect of adding the silane coupling agent tends to be much more pronounced. (plasticizer for rubber)

[0267] A modified conjugated diene polymer composition according to this embodiment may contain a rubber plasticizer in order to improve processability.

[0268] A mineral oil or a synthetic plasticizer that is liquid or has a low molecular weight is suitable as a rubber plasticizer.

[0269] Mineral oil-based rubber plasticizers, called process oils or extender oils, which are used to improve rubber softening, increase volume, and processability, are a mixture of an aromatic ring, a naphthene ring, and a paraffin chain. Plasticizers in which the number of carbon atoms in the paraffin chain accounts for 50 mass% or more of the total number of carbon atoms are called paraffin plasticizers, plasticizers in which the number of carbon atoms in the naphthene ring accounts for 30 mass% or more but 45 mass% or less of the total number of carbon atoms are called naphthene plasticizers, and plasticizers in which the number of aromatic carbon atoms in the total number of carbon atoms is 30 mass% or more of the total number of carbon atoms are called aromatic plasticizers.

[0270] The content of the rubber plasticizer is preferably from 0 mass parts to 100 mass parts, more preferably from 10 mass parts to 90 mass parts, and further preferably from 30 mass parts to 90 mass parts, based on 100 mass parts of the rubber-like polymer containing the rubber component A and the rubber component B. When the content of the rubber plasticizer is 100 mass parts or less to 100 mass parts of the rubber-like polymer, bleed-out tends to be inhibited and the surface stickiness of the rubber composition can be suppressed. [Production process of a modified conjugated diene polymer composition]

[0271] The modified conjugated diene polymer composition according to this embodiment can be prepared by blending the above-mentioned rubber component A, the rubber component B, and the filler(s), and if necessary, in addition to the rubber component A and the rubber component B, other rubber-like polymers, other fillers such as carbon black, and other additives such as silane coupling agents, plasticizers for rubber, etc., can be blended.

[0272] The method of mixing is not particularly limited, and for example, methods in which a common mixing apparatus such as an open roll, a Banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, a multi-screw extruder, etc. is used, and in which the components are mixed as a solution and then the solvent is removed by heating can be mentioned.

[0273] Of these, melt kneading using a roller, a Banbury mixer, a kneader, an extruder, etc. is preferred in terms of productivity and high quality of kneading.

[0274] Furthermore, a method in which the rubber component A, the rubber component B, filler(s) and the other raw materials are kneaded at one time and a method in which they are kneaded separately in several times can also be used.

[0275] The above-mentioned materials and kneading processes are not particularly limited, but it is preferable to knead the rubber component B and the filler(s) into a mass, then knead this kneaded mass with the rubber component A, and then, if necessary, mix the other additives such as silane coupling agent, plasticizer for rubber, etc.

[0276] With this method, the filler(s) can be more widely distributed in the rubber component B.

[0277] Concentrating the filler(s) in the rubber component B makes it possible to increase the area moment of the modified conjugated diene polymer composition according to this embodiment, and thereby tends to improve the fracture strength.

[0278] A modified conjugated diene polymer composition according to this embodiment can also be used as a vulcanizate composition prepared by vulcanization using a vulcanizing agent.

[0279] Examples of vulcanizing agents that can be mentioned include, but are not limited to, radical formers such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds.

[0280] Sulfur compounds include sulfur monochlorides, sulfur dichlorides, disulfide compounds, polymeric polysulfide compounds, etc.

[0281] The content of the vulcanizing agent is preferably 0.01 mass part to 20 mass parts, and more preferably 0.1 mass part to 15 mass parts, based on 100 mass parts of the rubber-like polymer containing the rubber component A and the rubber component B. A known method can be used as the vulcanization method, and the vulcanization temperature should preferably be 120°C to 200°C, and more preferably 140°C to 180°C.

[0282] During vulcanization, vulcanization accelerators can be used if necessary.

[0283] Already known materials can be used as vulcanization accelerators, and there can be mentioned, for example, but not limited to, sulfenamide-, guanidine-, thiuram-, aldehyde-amine-, aldehyde-ammonia-, thiazole-, thiourea-, dithiocarbamate-based vulcanization accelerators.

[0284] Examples of vulcanization aids that can be mentioned include, but are not limited to, zinc flower, stearic acid, etc.

[0285] The content of vulcanization accelerator is preferably 0.01 parts by mass to 20 parts by mass, and more preferably 0.1 parts by mass to 15 parts by mass, based on 100 parts by mass of rubbery polymer containing rubber component A and rubber component B.

[0286] To the modified conjugated diene polymer composition according to this embodiment, as long as the purpose of this embodiment is not impaired, other plasticizers and fillers, various additives such as heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, lubricants, etc., may be added.

[0287] Existing plasticizers can be used as additional plasticizers. Other fillers include calcium carbonate, magnesium carbonate, aluminum sulfate, barium sulfate, etc. Existing materials can be used as the above-mentioned heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants. [Tires]

[0288] The modified conjugated diene polymer composition according to this embodiment can be preferably used as a rubber composition for tires.

[0289] The modified conjugated diene polymer composition according to this embodiment can be used, for example, for various tires such as fuel-saving tires, all-season tires, high-performance tires, and winter tires, as well as various tire parts such as the tread, carcass, sidewall, bead portion, etc. In particular, since a modified conjugated diene polymer composition according to this embodiment, which contains a rubber-like polymer for tires composed of this modified conjugated diene polymer (rubber component A) and the rubber component B, has an excellent balance between snow performance and wet performance as well as abrasion resistance as a vulcanizate, it can be preferably used as a tread for winter tires. [Examples of implementation]

[0290] In the following, the embodiments are explained in more detail using concrete embodiments and comparative examples, but the embodiments are in no way limited by the following embodiments.

[0291] The evaluation methods of the respective physical properties of the materials used in the working examples and comparative examples are explained below. [Purification of 1,3-butadiene]

[0292] 1,3-Butadiene, which is used for the polymerization of a modified conjugated diene polymer, was purified using the following process (washing process).

[0293] This process was carried out under the conditions - circulating water volume of 1m 3 / hr and a renewal water volume of 0.1m 3 / hr - operated.

[0294] 1,3-Butadiene and rinse water were mixed using a static mixer (Static Mixer N60 Series, NORITAKE Co., Ltd.), then transferred to a decanter, and the 1,3-butadiene phase and the aqueous phase were separated using the decanter.

[0295] This was operated under the conditions of liquid temperature of 30°C and decanter pressure of 1.0 MPaG.

[0296] The residence time of the 1,3-butadiene phase in the decanter was 30 minutes.

[0297] The aqueous phase separated by the above-mentioned decanter was placed in a de-1,3-butadiene tank, then mixed with steam, heated to a temperature of 89°C, adjusting the total pressure to 0.01 MPaG, and thereby separating the 1,3-butadiene from the aqueous phase. (Oxygen removal process by oxygen scavengers)

[0298] Subsequently, after the above-mentioned washing process, the 1,3-butadiene was mixed with a solution of the oxygen scavenger - 10% aqueous solution of DICLEAN F-504 (KURITA KÖGYÖ) - under the condition of a circulating water flow of 1m3 / hr - in a static mixer, and the liquid-liquid extraction was carried out.

[0299] The mixture was then transferred to the decanter and separated into the 1,3-butadiene phase and the water phase using this decanter.

[0300] The residence time of the 1,3-butadiene phase in the decanter was 30 minutes. This was carried out under the following conditions: a liquid temperature of 30°C and a decanter pressure of 1.0 MPaG. (Removal process of the polymerization inhibitor)

[0301] Then, using a tower filled with a Pall ring, a 10% aqueous solution of sodium hydroxide was introduced at a circulation speed of 1m 3 / hr with the above-mentioned 1,3-butadiene (i.e., already subjected to the oxygen removal process by means of an oxygen removal agent), a liquid-liquid extraction was carried out, then this was transferred to another decanter, and in this other decanter the 1,3-butadiene phase and the aqueous phase were separated.

[0302] The residence time of 1,3-butadiene in the other decanter was 60 minutes. The polymerization inhibitor removal process was carried out under the following conditions: a liquid temperature of 30°C and a decanter pressure of 1.0 MPaG. (dewatering tower process)

[0303] Hexane was added to the 1,3-butadiene phase separated by the other decanter mentioned above, the concentration of 1,3-butadiene was adjusted to 50 mass%, and fed to a dewatering tower.

[0304] From the top (tower head) of the dewatering tower, after the azeotropic mixture of the distilled 1,3-butadiene and water was cooled and condensed, it was transferred to a decanter, and in this decanter the 1,3-butadiene phase and the aqueous phase were separated.

[0305] The aqueous phase was removed, and the 1,3-butadiene phase was returned to the inlet of the dewatering tower, and the dewatering tower process was carried out continuously.

[0306] The dewatered mixture of 1,3-butadiene and hexane was taken from the bottom (tower bottom) of the dewatering tower. (adsorption process)

[0307] The above mixture of 1,3-butadiene and hexane was passed through a 500L activated alumina desiccant dryer (a vertical cylinder tank, HITACHI, Ltd.), which removed trace impurities from 1,3-butadiene by adsorption, thus obtaining the purified 1,3-butadiene. [Cleaning of styrene]

[0308] Styrene used for the polymerization of a modified conjugated diene polymer was purified by the following process.

[0309] The γ-alumina, which was formed into a cylindrical shape of 3 mmφ × 3 mm, was soaked in a 0.6% aqueous solution of palladium chloride and dried for one day and one night at a temperature of 100°C.

[0310] The dried product was then reduced under hydrogen flow at a temperature of 400°C for 16 hours, and a hydrogenated catalyst with a composition of Pd(0.3%) / γ-Al2O3 was obtained.

[0311] 2000g of the hydrogenation catalyst thus obtained was filled into a tubular reactor, the temperature of the catalyst was kept at 80°C, and the purified styrene was obtained by adding styrene to the reactor and circulating it for a period of 8 hours. [Purification of normal hexane]

[0312] Normal hexane, which is used for the polymerization of a modified conjugated diene polymer, was purified by the following process.

[0313] 2000g of molecular sieve 13-X (Union Shöwa) was filled into a tubular reactor, and the purified normal hexane was obtained by adding normal hexane to the reactor and circulating it at room temperature for a period of 24 hours. [Purity analysis of the starting materials (calculating the total amount of impurities)]

[0314] Allenes, acetylenes and amines were quantitatively analyzed as impurities in the starting materials.

[0315] Allenes and acetylenes were analyzed qualitatively and quantitatively using gas chromatography. Rt-Alumina BOND / MAPD column (SHIMADU SEISAKUSHO) was used.

[0316] Furthermore, the amines were extracted with boric acid and quantitatively analyzed by titration, and from this the total amount (ppm) of impurities was calculated. [(physical property 1) amount of bonded styrene]

[0317] A sample of 100g of the modified conjugated diene polymers was taken, made up to 100mL with chloroform, dissolved, and used as the analytical sample.

[0318] The amount of bound styrene (mass %) relative to 100 mass % of the modified conjugated polymer, which is a sample, was measured based on the absorption amount of the ultraviolet absorption wavelength (around 254 nm) by the phenyl group of styrene (SHIMADU SEISAKUSHO Co., spectrophotometer of the company "UV-2450"). [(Physical Properties 2) Microstructure at the butadiene region (1,2-vinyl compound amount)]

[0319] 50 mg of each modified conjugated diene polymer was taken as a sample, dissolved in 10 mL of carbon disulfide and used as an analytical sample.

[0320] The infrared spectrum was measured in the range of 600 to 1000cm -1was measured using a solution cell, and the microstructure at the butadiene region, i.e., the 1,2-vinyl compound amount (mol%), was calculated according to a formula of Hampton's method (a method described in RR Hampton, Analytical Chemistry 21, 923 (1949)) by absorption at a predetermined wavenumber (NIPPON BUNKÖ (Eng. JASCO), Fourier transform infrared spectrophotometer "FT-IR230"). [(physical property 3) Mooney viscosity]

[0321] The Mooney viscosity of each modified conjugated diene polymer used as a sample was measured using a Mooney viscometer (trade name “VR1132”, UESHIMA SEISAKUSHO Co., Ltd.) with an L-shaped rotor according to JIS K6300.

[0322] The measurement was taken at a temperature of 100°C.

[0323] A sample was preheated for approximately 1 minute at the measuring temperature, then the rotor was rotated at a speed of 2 rpm, and the torque was measured after 4 minutes as the Mooney viscosity (ML (1 + 4) ) measured. [(physical property 4) molecular weight]

[0324] A chromatogram was measured using a modified conjugated diene polymer as a sample using a GPC instrument (TOSO, trade name "HLC-8320GPC") in which three columns are connected with polystyrene gel as a packing material and an RI detector (TOSO, trade name "HLC8020"). Based on a calibration curve prepared using standard polystyrene, the weight-average molecular weight (Mw1), the number-average molecular weight (Mn1), the molecular weight distribution (Mw1 / Mn1), and the peak-top molecular weight (Mp1) of the modified conjugated diene polymer were determined.

[0325] THF (tetrahydrofuran) was used as eluent.

[0326] The column used was a combination in which three columns from TŌSŌ, trade name “TSKgel SuperMultipore HZ-H”, and in front of them one column from TŌSŌ, trade name “TSKguardcolumn SuperMP (HZ) -H” as a protective column were connected.

[0327] 10 mg of the respective sample for measurement was dissolved in 20 mL of THF and prepared as a measurement solution. 10 µL of this measurement solution was injected into the GPC measuring apparatus, and the measurements were performed under the following conditions: oven temperature: 40 °C and THF flow rate: 0.35 mL / min.

[0328] The above peak molecular weight (Mp1) was determined as follows.

[0329] In the GPC curve obtained by the measurement, the peak detected for the component with the highest molecular weight was selected. For the selected peak, the molecular weight corresponding to the local maximum of the peak was calculated and defined as the peak-top molecular weight. [(physical property 5) degree of modification]

[0330] A chromatogram of each modified conjugated diene polymer as a measurement sample was measured by applying the property that the modified basic polymer component is adsorbed in a GPC column filled with silica gel as a filler.

[0331] The degree of modification was determined by calculating the adsorption amount on the silica column based on the difference between the chromatogram measured with the polyethylene gel acid and the chromatogram measured with the silica column of the measuring solution containing the above-mentioned sample to be measured and the low molecular weight internal standard polystyrene.

[0332] Specifically, this works as follows: Preparation of the sample solution for the measurement: 10 mg of each of the above-mentioned samples to be measured and 5 mg of standard polystyrene were dissolved in 20 mL of THF (tetrahydrofuran) and used as a sample solution to be measured. GPC measurement conditions using a polystyrene column: 10µL of the sample solution to be measured was analysed in a “HLC-8320 GPC” (trade name) from TŌSŌ with THF as eluent under the following conditions: column temperature: 40°C, THF flow: 0.35 mL / min., and a chromatogram was recorded using an RI detector. The column used was a combination consisting of three columns from TŌSŌ (trade name "TSKgel SuperMultipore HZ-H"), and one guard column from TŌSŌ (trade name "TSKguardcolumn SuperMP (HZ)-H"). GPC measurement conditions using a silica column: 50 µL of the sample solution to be measured was injected into a "HLC-8320 GPC" (trade name) from TŌSŌ using THF as the eluent under the following conditions: column temperature: 40°C, THF flow: 0.5 mL / min. A chromatogram was recorded using an RI detector. A combination of three columns (Zorbax PSM-1000S, PSM-300S, and PSM-60S) was used as the column, with a "DIOL 4.6 x 12.5 mm 5 micron" (trade name) connected in front as the guard column. Calculation method of the degree of modification:

[0333] The degree of modification (mass %) was determined using the formula below, where P1 is the peak area of ​​the sample and P2 is the peak area of ​​the standard polystyrene based on the total peak area of ​​100% of the chromatogram using the polystyrene column, P3 is the peak area of ​​the sample and P4 is the peak area of ​​the standard polystyrene based on the total peak area of ​​100% of the chromatogram using the silica column. Degree of modification (mass %) = [1-(P2×P3) / (P1×P4)]×100 (in the formula: P1 + P2 = P3 + P4 = 100) [(physical property 6) degree of modification of the low molecular weight component]

[0334] Using the calibration curve prepared according to the measurement method of the above-mentioned (physical property 4), the weight average molecular weight (Mw2), the number average molecular weight (Mn2), the molecular weight distribution (Mw2 / Mn2), and the peak top molecular weight (Mp2) of the modified conjugated diene polymer were determined.

[0335] However, the above-mentioned peak apex molecular weight (Mp2) is taken as the molecular weight of the peak apex on the molecular weight curve or, if multiple peak apex are present, as the molecular weight of the peak apex for the smallest molecular weight, and the height of the diagram at the molecular weight which is half of this peak apex molecular weight (Mp2) (i.e., the molecular weight of the low molecular weight component) is denoted by L1.

[0336] The height of the molecular weight obtained by dividing by 2 the peak top molecular weight (Mp2) in the graph measured by the measurement method of (physical property 5) using a silica column (i.e., the height of the molecular weight of the low molecular weight component) was designated as L2.

[0337] The component with a molecular weight equal to half of the above peak molecular weight (Mp2) is considered as a low molecular weight component.

[0338] The degree of modification of the low molecular weight component was calculated using the formula (1-L2 / L1) x 100. (physical property 7) Degree of modification of the low molecular weight component

[0339] This was calculated by dividing the degree of modification (FL) of the low-molecular-weight component (with a molecular weight of half the peak molecular weight) of the above-mentioned (physical property 6) by the degree of modification (FT) of the entire conjugated diene polymer of the above-mentioned (physical property 5). Degree of modification of the low-molecular-weight component = FL / FT [(physical property 8) glass transition temperature]

[0340] To determine the glass transition temperature, a DSC curve was recorded from the sample of the respective non-oil-extended modified conjugated diene polymer according to ISO 22768:2006 using a Mac Science DSC3200S differential scanning calorimeter while increasing the temperature from -100°C to 20°C / min under a helium flow of 50 ml / min. The peak (inflection point) of the DSC derivative curve was defined as the glass transition temperature. [(physical property 9) shrinkage factor (g')]

[0341] The respective molecular weight was determined based on the solution viscosity and light scattering method by analyzing the respective modified conjugated diene polymer as a sample using a GPC light scattering meter with a viscosity detector in which three columns filled with polystyrene gel are connected, and thus the chromatogram was determined.

[0342] The eluent used was a mixed solution of tetrahydrofuran and triethylamine (THF in TEA: prepared by mixing 5 ml of triethylamine with 1 L of tetrahydrofuran).

[0343] The columns used were a combination of a guard column from TŌSŌ, trade name “TSKguard column HHR-H”, as well as columns from TŌSŌ, trade name “TSKgel G6000 HHR”, “TSKgel G5000 HHR” and “TSKgel G4000 HHR”.

[0344] The GPC light scattering instrument with a viscosity detector (trade name "Viscotek TDAmax", Malvern) was used under the following conditions: oven temperature: 40°C and THF flow rate: 1.0 mL / min.

[0345] As a sample solution for measurement, 10 mg of sample to be measured was dissolved in 20 mL of THF, and 200 µL of sample solution was injected into the GPC measuring apparatus, and the specific viscosity was measured.

[0346] Using the specific viscosity and molecular weight of the sample solution thus obtained for measurement, the shrinkage factor (g') was calculated.

[0347] A correlation between the specific standard viscosity [η]0 and the molecular weight M from 1000 to 20000000 (molecular weight M) was established using the correlation formula between the specific viscosity and the molecular weight ([η] = KMα ([η]: specific viscosity, M: molecular weight), using logK = -3.883, α = 0.771 as the constant (K, α), and from this, the specific viscosity [η] per molecular weight M was calculated based on the correlation between the specific viscosity [η] versus the specific standard viscosity [η]0, that is, with the formula [η] / [η]0 per molecular weight M, and the average value thereof was taken as the shrinkage factor (g').

[0348] The shrinkage factor (g') is a value averaged at an M of 1,000K to 2,000K. [(physical property 10) Nitrogen content]

[0349] The nitrogen content was measured using a trace total nitrogen analyzer (TN-2100H, Mitsubishi Chemical Analytech). [modified conjugated diene polymer (sample no. 1)]

[0350] A tub-shaped pressure vessel having an internal volume of 10 L, a ratio (L / D) between the internal height (L) and the diameter (D) of 4.0, as well as an inlet on the bottom, an outlet from the top, a stirring device, and a jacket for temperature regulation was used as the polymerization reactor.

[0351] Pre-dehumidified 1,3-butadiene (19 g / min), styrene (10.3 g / min), and n-hexane (143.9 g / min) were mixed. The mixture contained 10 ppm allenes, 12 ppm acetylenes, and 1 ppm amines. The total impurities were 23 ppm.

[0352] In a static mixer installed in the center of the pipeline leading to the reactor inlet, through which the mixed solution is fed, 0.08 mmol / min of n-butyllithium was added to inactivate the remaining impurities, mixed, and then continuously fed to the bottom of the reactor. Furthermore, 2,2-bis(2-oxolanyl)propane, as a polar substance, and n-butyllithium, as a polymerization initiator, were fed at a rate of 0.02 g / min to the bottom of the polymerization reactor, where vigorous mixing takes place by means of the stirring device, and thus continuously supplied to the polymerization reaction. The temperature of the polymerization solution was regulated so that a temperature of 75°C prevailed at the outlet at the top of the reactor.

[0353] Once the polymerization was sufficiently stabilized, a small amount of polymerization solution was withdrawn from the outlet at the reactor head before the addition of the coupling agent, and after 0.2 g of antioxidant (BHT) per 100 g of polymer was added, the solvent was removed.

[0354] Subsequently, tetraglycidyl-1,3-bisaminomethylcyclohexane was added as a modifier to the polymerization solution flowing out of the reactor outlet at a rate of 0.05 mmol / min, and the polymer solution was mixed with the modifier while passing through the static mixer, and the modification reaction took place.

[0355] After the modification reaction, 0.2 g of antioxidant (BHT) per 100 g of polymer was continuously added to the polymer solution as an n-hexane solution, and the coupling reaction was terminated. Simultaneously with the antioxidant, 25 g of oil (H&R, Vivatec 500) per 100 g of polymer was continuously added and mixed using a static mixer. The solvent was removed by steam stripping, yielding a modified conjugated diene polymer (Sample 1). The physical properties of Sample 1 are shown in Table 1. [modified conjugated diene polymer (sample no. 2)]

[0356] A modified conjugated diene polymer (Sample 2) was obtained in the same way as that (Sample 1), except that the polymerization initiator was changed to a pre-prepared mixed solution of piperidinolithium (also called “1-lithiopiperidine”) as lithium amide and n-butyllithium (the molar ratio between the piperidinolithium and n-butyllithium: piperidinolithium: n-butyllithium = 0.75: 0.25 molar ratio).

[0357] The physical properties of Sample 2 are shown in Table 1. [modified conjugated diene polymer (sample no. 3)]

[0358] A modified conjugated diene polymer (Sample 3) was obtained in the same manner as that (Sample 1), except that the modifier was changed to 3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine.

[0359] The physical properties of Sample 3 are shown in Table 1. [modified conjugated diene polymer (sample no. 4)]

[0360] A modified conjugated diene polymer (Sample 4) was obtained in the same way as that (Sample 3), except that the polymerization initiator was changed to a pre-prepared mixed solution of piperidinolithium (also called "1-lithiopiperidine") as lithium amide and n-butyllithium (the molar ratio between the piperidinolithium and n-butyllithium was: piperidinolithium : n-butyllithium = 0.75 : 0.25 molar ratio).

[0361] The physical properties of Sample 4 are shown in Table 1. [modified conjugated diene polymer (sample no. 5)]

[0362] A modified conjugated diene polymer (Sample 5) was obtained in the same way as that (Sample 1), except that the modifier was changed to tris(3-trimethoxysilylpropyl)amine and the feed rate was changed to 0.034 mmol / min.

[0363] The physical properties of sample 5 are shown in Table 1. [modified conjugated diene polymer (sample no. 6)]

[0364] A modified conjugated diene polymer (Sample 6) was obtained in the same way as that (Sample 5), except that the polymerization initiator was changed to a pre-prepared mixed solution of piperidinolithium (also called "1-lithiopiperidine") as lithium amide and n-butyllithium (the molar ratio between the piperidinolithium and n-butyllithium was: piperidinolithium : n-butyllithium = 0.75 : 0.25 molar ratio).

[0365] The physical properties of Sample 6 are shown in Table 1. [modified conjugated diene polymer (sample no. 7)]

[0366] A modified conjugated diene polymer (Sample 7) was obtained in the same way as that (Sample 1), except that the modifier was changed to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine and the feed rate was changed to 0.026 mol / min.

[0367] The physical properties of sample 7 are shown in Table 1. [modified conjugated diene polymer (sample no. 8)]

[0368] A modified conjugated diene polymer (Sample 8) was obtained in the same way as that (Sample 7), except that the polymerization initiator was changed to a pre-prepared mixed solution of piperidinolithium (also called "1-lithiopiperidine") as lithium amide and n-butyllithium (the molar ratio between the piperidinolithium and n-butyllithium was: piperidinolithium : n-butyllithium = 0.75 : 0.25 molar ratio).

[0369] The physical properties of Sample 8 are shown in Table 1. [modified conjugated diene polymer (sample no. 9)]

[0370] A tub-shaped pressure vessel having an internal volume of 10 L, a ratio (L / D) between the internal height (L) and the diameter (D) of 4.0, as well as an inlet on the bottom, an outlet from the top, a stirring device, and a jacket for temperature regulation was used as the polymerization reactor.

[0371] Pre-dehumidified 1,3-butadiene (20.9 g / min), styrene (8.4 g / min), and n-hexane (143.9 g / min) were mixed. 10 ppm of allenes, 12 ppm of acetylenes, and 1 ppm of amines were detected in the mixture. The total impurities were 23 ppm.

[0372] In a static mixer installed in the center of the pipeline leading to the reactor inlet, through which the mixed solution is fed, 0.08 mmol / min of n-butyllithium was added to inactivate the remaining impurities, mixed, and then continuously fed to the bottom of the reactor. Furthermore, 2,2-bis(2-oxolanyl)propane, as a polar substance, and n-butyllithium, as a polymerization initiator, were fed at a rate of 0.02 g / min to the bottom of the polymerization reactor, where vigorous mixing takes place by means of the stirring device, and thus continuously supplied to the polymerization reaction. The temperature of the polymerization solution was regulated so that a temperature of 75°C prevailed at the outlet at the top of the reactor.Once the polymerization was sufficiently stabilized, a small amount of polymerization solution was withdrawn from the outlet at the reactor head before the addition of the coupling agent, and after 0.2 g of antioxidant (BHT) per 100 g of polymer was added, the solvent was removed.

[0373] Subsequently, 3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine was added as a modifier to the polymerization solution flowing out of the reactor outlet at a rate of 0.05 mmol / min, and the polymer solution with the modifier was mixed while passing through the static mixer, and the modification reaction took place.

[0374] After the modification reaction, 0.2 g of antioxidant (BHT) per 100 g of polymer was continuously added to the polymer solution as an n-hexane solution, and the coupling reaction was terminated. Simultaneously with the antioxidant, 5 g of oil (H&R, Vivatec 500) per 100 g of polymer was continuously added and mixed using a static mixer. The solvent was removed by steam stripping, yielding a modified conjugated diene polymer (Sample 9). The physical properties of Sample 9 are shown in Table 2. [modified conjugated diene polymer (sample no. 10)]

[0375] A modified conjugated diene polymer (Sample 10) was obtained in the same way as Sample 3, except that the starting materials were mixed under the same conditions as 21 g / min butadiene, 8.8 g / min styrene, and 143.9 g / min n-hexane, and the addition amount of the polar substance was changed to 0.015 mmol. The physical properties of Sample 10 are shown in Table 2. [modified conjugated diene polymer (sample no. 11)]

[0376] A modified conjugated diene polymer (Sample 11) was obtained in the same way as Sample 3, except that the addition rate of n-butyllithium as a polymerization initiator was changed to 0.24 mmol / min, the addition rate of 2,2-bis(2-oxolanyl)propane was changed to 0.01 g / min, and the addition rate of 3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine as a modifier was changed to 0.03 mmol / min. The physical properties of Sample 11 are shown in Table 2. [modified conjugated diene polymer (sample no. 12)]

[0377] A modified conjugated diene polymer (Sample 12) was obtained in the same way as Sample 3, except that the addition rate of n-butyllithium as a polymerization initiator was changed to 0.30 mmol / min, the addition rate of 2,2-bis(2-oxolanyl)propane was changed to 0.03 g / min, and the addition rate of 3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine as a modifier was changed to 0.08 mmol / min. The physical properties of Sample 12 are shown in Table 2. [modified conjugated diene polymer (sample no. 13)]

[0378] A modified conjugated diene polymer (Sample 13) was obtained in the same way as Sample 3, except that the addition rate of n-butyllithium as a polymerization initiator was changed to 0.40 mmol / min, the addition rate of 2,2-bis(2-oxolanyl)propane was changed to 0.04 g / min, and the addition rate of 3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine as a modifier was changed to 0.11 mmol / min. The physical properties of Sample 13 are shown in Table 2. [modified conjugated diene polymer (sample no. 14)]

[0379] 15 ppm of allenes, 13 ppm of acetylenes, and 2 ppm of amines were detected in a mixture of 1,3-butadiene, styrene, and n-hexane. The total impurities were 30 ppm. Except for using this mixture, a modified conjugated diene polymer (Sample 14) was obtained in the same manner as Sample 3. The physical properties of Sample 14 are shown in Table 2. [modified conjugated diene polymer (sample no. 15)]

[0380] A modified conjugated diene polymer (Sample 15) was obtained in the same way as Sample 3, except that the addition rate of 3-trimethoxysilylpropyl-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine as a modifier was changed to 0.01 mmol / min. The physical properties of Sample 15 are shown in Table 2. [modified conjugated diene polymer (sample no. 16)]

[0381] A 10L autoclave equipped with a stirrer and a jacket was washed, dried, and purged with nitrogen. 592g of 1,3-butadiene, 208g of styrene, and 5kg of cyclohexane were added, from which impurities such as water were previously removed. 1.47g of 2,2-bis(2-oxolanyl)propane was then added as a polar substance. 2.5mmol of a previously prepared mixed solution of piperidinolithium as lithium amide and n-butyllithium (the molar ratio of piperidinolithium to n-butyllithium was 0.75:0.25) was added, and polymerization was initiated at a temperature of 52°C. The polymerization was carried out as an adiabatic polymerization, and the maximum temperature reached 70°C.After the maximum temperature was reached, the polymerization was continued for another 5 minutes, and a sample was taken from the reaction solution obtained, i.e. the polymer solution containing the conjugated diene polymer from the conjugated diene compound and the aromatic vinyl compound, and analyzed after removal of the solvent.

[0382] Cyclohexane solution containing 1.3 mmol of 3-trimethoxysilylpropyl-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine was added to the polymerization solution after sampling, and the reaction was carried out for 15 minutes. Then, 2 g of antioxidant (BHT) was added to the resulting polymer solution, followed by removal of the solvent, and the modified conjugated diene polymer (Sample 16) was obtained. The physical properties of Sample 16 are shown in Table 2.

[0164] [Table 1] modified conjugated diene polymer Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 Manufacturing conditions 1,3-Butadien (g / min.) 19 19 19 19 19 19 19 19 Styren (g / min.) 10.3 10.3 10.3 10.3 10.3 10.3 10.3 10.3 n-hexane (g / min.) 143.9 143.9 143.9 143.9 143.9 143.9 143.9 143.9 polar substance *1 (g / min.) 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 n-Butyllithium for the treatment (mmol / min.) 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 polymerization initiator Type n-Butyllithium 1-Lithiopiperidine n-Butyllithium 1-Lithiopiperidine n-Butyllithium 1-Lithiopiperidine n-Butyllithium 1-Lithiopiperidine added amount (mmol / min.) 0.18 0.18 0.18 0.18 0.18 0.18 0.18 0.18 Modifiers Type *2 *2 *3 *3 *4 *4 *5 *5 added amount (mmol / min.) 0.050 0.050 0.050 0.050 0.034 0.034 0.026 0.026 Extension oil *6 added amount Mass proportions 25 25 25 25 25 25 25 25 Analysis value (physical property 1) Amount of bonded styrene (mass %) 35 35 35 35 35 35 35 35 (physical property 2) 1,2-vinyl compound amount (mol%) 40 40 40 40 40 40 40 40 (physical property 3) Mooney viscosity 80 80 78 78 75 75 70 70 (physical property 4) weight-average molecular weight (Mw) × 10 4 65 65 75 75 80 80 90 90 (physical property 4) Number average molecular weight (Mn) × 10 4 30 31 38 36 41 40 43 44 (physical property 4) Molecular weight (Mw / Mn) 2.17 2.10 1.97 2.08 1.95 2.00 2.09 2.05 (physical property 5) degree of modification (mass %) 55 90 78 92 76 91 80 92 (physical property 6) Degree of modification of the low molecular weight comp (mass %) 40 75 45 76 43 75 43 75 (physical property 7) Degree of modification of the low molecular weight comp 0.73 0.83 0.58 0.83 0.57 0.82 0.54 0.82 (physical property 8) glass transition temperature (° C) -30 -30 -30 -30 -30 -30 -30 -30 (physical property 9) shrinkage factor 0.81 0.79 0.72 0.73 0.66 0.67 0.52 0.51 (physical property 10) Nitrogen content (mass ppm) 20 50 20 53 13 39 10 30

[0383] The meaning of the reference symbols in Table 1 and Table 2 is explained below. *1 2,2-bis(2-oxolanyl)propane *2 Tetraglycidyl-1,3-bisaminomethylcyclohexane *3 3-Trimethoxysilylpropyl-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine *4 Tris(3-trimethoxysilylpropyl)amine *5 Tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine *6 Process oil (H&R Vivatec 500) [Modified conjugated diene polymer composition (Working Examples 1 to 20, Comparative Examples 1 and 9)] (Working Examples 9 to 12 are reference examples)

[0384] The modified conjugated diene polymers (samples 1 to 16) shown in Table 1 and Table 2 above, SBR-A, SBR-B, natural rubber (NR) and polybutadiene (BR) as starting rubber and the following materials were kneaded according to the method described below, and the following unvulcanized rubber compositions and then the vulcanized rubber compositions were prepared.

[0385] The results are presented in Tables 3 to 5.

[0386] The values ​​in parentheses in Table 3 to Table 5 represent the amount of process oil in the samples. - modified conjugated diene polymer: Sample Nos. 1 to 16 - SBR-A (ASAHI KASEI, TOUGHDEN 4850, glass transition temperature = -12°C) - SBR-B (ASAHI KASEI, TOUGHDEN 1834, glass transition temperature = -70°C) -NR (natural rubber, glass transition temperature = -70°C) - BR (UBE KÖSAN, BR 150, glass transition temperature = -105°C) - Extension oil (H&R, Vivatec 500) - Silicon dioxide (EVONIK JAPAN, UKTRASIL 7000GR, specific nitrogen adsorption surface area = 175m 2 / G) - Silane coupling agent (EVONIK JAPAN, Si75) - Carbon Black (TŌKAI Carbon, SIEST KH (N 339)) - Zinc flower (MITSUI KINZOKU KÖGYÖ, Zinc flower No. 1) - Stearic acid - Wax (OUCHI SHINKÖ KAGAKU KÖGYÖ, SUNNOC) - Anti-aging agent (N-isopropyl-N'-phenyl-p-phenylenediamine) - Sulfur - Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazylsulfinamide) - Vulcanization accelerator 2 (diphenylguanidine) (Examples 1 to 13, 15 to 20, Comparative Examples 1 to 9)

[0387] The ingredients shown in Table 3 to Table 5 were kneaded according to the following method, and thus the unvulcanized rubber compositions and then the vulcanized rubber compositions were prepared therefrom.

[0388] The respective raw rubber, silica, silane coupling agent, carbon black, sphalerium, stearic acid, wax, and anti-aging agent were kneaded in the first kneading stage using a kneader (internal volume 0.5 L) equipped with a temperature control device under the conditions of filling ratio: 65%, rotor speed: 50 rpm, for a period of 4 minutes. The compositions were obtained by regulating the outlet temperature of the kneader to a temperature of 155 to 160°C.

[0389] Subsequently, the compositions obtained as above were each cooled to room temperature and kneaded in a second kneading stage for a duration of 3.5 minutes using the above-mentioned kneader. In this case, the outlet temperature of the kneader was also regulated to a temperature of 155 to 160°C. The outlet temperature was regulated after kneading by measuring the temperature of the respective composition discharged from the kneader.

[0390] Further, after each of the compositions obtained as described above was cooled to room temperature, these unvulcanized rubber compositions were heated by means of an oven to a temperature of 70°C for 30 minutes, then, in the third kneading stage, after each of them was kneaded by means of a kneader set at a temperature of 70°C for 30 seconds without any additives, and after the addition of sulfur and vulcanization accelerator for 1.5 minutes, they were discharged at a temperature of 105°C, and thus the unvulcanized rubber compositions were obtained.

[0391] The respective Mooney viscosity of the compositions of the unvulcanized rubber compositions was evaluated according to the following method.

[0392] Subsequently, the unvulcanized rubber compositions were vulcanized in the vulcanization press at a temperature of 160°C for a period of 20 minutes, and vulcanized rubber mats were produced.

[0393] The snow performance, wet performance, abrasion resistance and breaking strength of the respective vulcanized rubber mats were evaluated according to the following methods. (Example 14)

[0394] After Sample 9 as the starting rubber and silica were kneaded in the first kneading stage under the conditions of a rotor speed of 50 rpm for 1 minute, Sample 7 as the starting rubber, silica, silane coupling agent, carbon black, sphalerium, stearic acid, wax, and antiaging agent were added and kneaded for 4 minutes. The compositions were obtained by regulating the outlet temperature of the kneader to a temperature of 155 to 160°C.

[0395] Subsequently, the compositions obtained as above were each cooled to room temperature and kneaded in a second kneading stage for a duration of 3.5 minutes using the above-mentioned kneader. In this case, the outlet temperature of the kneader was also regulated to a temperature of 155 to 160°C. The outlet temperature was regulated after kneading by measuring the temperature of the respective composition discharged from the kneader.

[0396] Further, after each of the compositions obtained as described above was cooled to room temperature, these unvulcanized rubber compositions were heated by means of an oven to a temperature of 70°C for 30 minutes, then, in the third kneading stage, after each of them was kneaded by means of a kneader set at a temperature of 70°C for 30 seconds without any additives, and after the addition of sulfur and vulcanization accelerator for 1.5 minutes, they were discharged at a temperature of 105°C, and thus the unvulcanized rubber compositions were obtained.

[0397] The respective Mooney viscosity of the compositions of the unvulcanized rubber compositions was evaluated according to the following method.

[0398] Subsequently, the unvulcanized rubber compositions were vulcanized in the vulcanization press at a temperature of 160°C for a period of 20 minutes, and vulcanized rubber mats were produced.

[0399] The snow performance, wet performance, abrasion resistance and breaking strength of the respective vulcanized rubber mats were evaluated according to the following methods. [Method for measuring physical properties](Mooney viscosity of mass (Mooney viscosity of composition) (physical property 11))

[0400] After the second kneading step, the Mooney viscosity of each rubber composition was measured as a sample using a Mooney viscometer (trade name “VR1132”, UESHIMA SEISAKUSHO Co., Ltd.) with an L-shaped rotor according to JIS K6300.

[0401] The measurement was taken at a temperature of 100°C.

[0402] A sample was preheated for approximately 1 minute at the measuring temperature, then the rotor was rotated at a speed of 2 rpm, and the torque was measured after 4 minutes as the Mooney viscosity (ML (1 + 4) ) measured.

[0403] The measured value of Comparative Example 1 was set to 100 and represented as an exponent, and this was used as an indicator of processability.

[0404] The larger the exponent, the better the formability into film. (viscoelastic parameter (physical properties 12, 13))

[0405] The viscoelastic parameters of the respective rubber compositions after vulcanization were measured in a torsion mode using an "ARES" viscoelastic tester from Rheometrics Scientific. The respective measured values ​​were set to 100 relative to the result of the rubber composition of Comparative Example 1 and expressed as an exponent.

[0406] A tan δ measured at a frequency of 10 Hz and a strain of 1% at 0°C was used as an indicator of wet performance. The larger the values, the better the wet adhesion.

[0407] The storage elastic modulus (G'), measured at a temperature of -20°C, a frequency of 10 Hz, and a strain of 1%, was used as an indicator of snow performance. The higher the values, the better the snow performance. (Friction resistance (physical property 14))

[0408] The respective rubber compositions were measured for wear after vulcanization under a load of 44.4 N after 1000 revolutions according to JIS K 6264-2 using an Akron abrasion tester (YASUDA SEIKI SEISAKUSHO). The wear was set to 100 based on the result of Comparative Example 1 and expressed as an exponent. The larger the exponent, the better the friction resistance. (Tensile strength (physical property 15))

[0409] For each rubber composition after vulcanization, the tear strength was measured according to the tensile test method of JIS K6251, and this was set to 100 and expressed as an exponent based on the result of Comparative Example 1. (Processability into film (Physical Property 16))

[0410] The rubber compositions obtained after the first kneading stage were each processed into a film-shaped rubber composition in an open roll set at a temperature of 70°C.

[0411] The respective film quality of the obtained sheet-shaped rubber compositions was visually evaluated in five stages based on the following criteria.

[0412] The higher the points, the better the formability into film. 5 : When processed by roller, it has good cohesion, the film has a smooth surface, and the edges of the film are not jagged. 4 : When processed with the roller, it has good cohesion, but the film has a not so smooth surface, and the edges of the film are a bit jagged. 3 : When processed with the roller, it has a little poor cohesion, the film has a little rough surface, and the edges of the film are a little jagged. 2 : When processed with the roll, it has a little poor cohesion, the film has a rough surface, and the edges of the film are jagged. 1: When processed with a roll, it has poor cohesion, the film has a rough surface, and the edges of the film are jagged.

[0176] [Table 3] Composition [mass fractions] 1 2 3 4 5 6 7 8 9 10 modified conjugated diene polymer Sample 1 87,5 (17,5) Sample 2 87,5 (17,5) Sample 3 87,5 (17,5) Sample 4 87,5 (17,5) Sample 5 87,5 (17,5) Sample 6 87,5 (17,5) Sample 7 87,5 (17,5) 87,5 (17,5) Sample 8 87,5 (17,5) 87,5 (17,5) Sample 9 31,5 (1,5) 31,5 (1,5) 31,5 (1,5) 31,5 (1,5) 31,5 (1,5) 31,5 (1,5) 31,5 (1,5) 31,5 (1,5) Sample 10 Sample 11 Sample 12 Sample 13 Sample 14 Sample 15 Sample 16 SBR A SBR B NR (natural rubber) 30 30 BR Extension oil 23 23 23 23 23 23 23 23 24.5 24.5 Silicon dioxide 75 75 75 75 75 75 75 75 75 75 Silane coupling agent 6 6 6 6 6 6 6 6 6 6 Carbon Black 5 5 5 5 5 5 5 5 5 5 Spangle 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Stearic acid 1 1 1 1 1 1 1 1 1 1 wax 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Anti-aging agents 2 2 2 2 2 2 2 2 2 2 sulfur 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 Vulcanization accelerator 1 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 Vulcanization accelerator 2 2 2 2 2 2 2 2 2 2 2 [Table 4] Composition [mass fractions] 11 12 13 14 15 16 17 18 19 20 modified conjugated diene polymer Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 87,5 (17,5) 87,5 (17,5) 87,5 (17,5) 112,5 (22,5) 62,5 (12,5) Sample 8 87,5 (17,5) Sample 9 31,5 (1,5) 10,5 (0,5) 52,5 (2,5) 31,5 (1,5) 31,5 (1,5) 31,5 (1,5) 31,5 (1,5) Sample 10 Sample 11 87,5 (17,5) Sample 12 87,5 (17,5) Sample 13 Sample 14 87,5 (17,5) Sample 15 Sample 16 SBR A 105 (35) SBR B 41,3 (11,3) NR (natural rubber) BR 30 30 Extension oil 24.5 24.5 13.2 23 19 27 5.5 23 23 23 Silicon dioxide 75 75 75 75 75 75 75 75 75 75 Silane coupling agent 6 6 6 6 6 6 6 6 6 6 Carbon Black 5 5 5 5 5 5 5 5 5 5 Spangle 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Stearic acid 1 1 1 1 1 1 1 1 1 1 wax 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Anti-aging agents 2 2 2 2 2 2 2 2 2 2 sulfur 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 Vulcanization accelerator 1 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 Vulcanization accelerator 2 2 2 2 2 2 2 2 2 2 2 [Table 5] Comparison examples Composition [mass fractions] 1 2 3 4 5 6 7 8 9 modified conjugated diene polymer Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 125 (25) 50 (10) 87,5 (17,5) Sample 8 125 (25) Sample 9 105 (5) 63 (3) 31,5 (1,5) 31,5 (1,5) 31,5 (1,5) 31,5 (1,5) Sample 10 37,5 (17,5) 87,5 (17,5) Sample 11 Sample 12 Sample 13 87,5 (17,5) Sample 14 Sample 15 87,5 (17,5) Sample 16 87,5 (17,5) SBR A SBR B NR (natural rubber) BR Extension oil 17 17 37 29 7 23 23 23 23 Silicon dioxide 75 75 75 75 75 75 75 75 75 Silane coupling agent 6 6 6 6 6 6 6 6 6 Carbon Black 5 5 5 5 5 5 5 5 5 Spangle 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Stearic acid 1 1 1 1 1 1 1 1 1 wax 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Anti-aging agents 2 2 2 2 2 2 2 2 2 sulfur 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 Vulcanization accelerator 1 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 1.7 Vulcanization accelerator 2 2 2 2 2 2 2 2 2 2 [Table 6] Example 1 2 3 4 5 6 7 8 9 10 (physical property 11) Mooney viscosity of the composition 90 88 95 94 98 97 101 100 100 100 (physical property 12) Performance in snow 105 105 107 106 109 110 115 117 105 107 (physical property 13) Wet performance 105 105 106 105 110 110 115 118 105 106 (physical property 14) Friction resistance 100 105 101 107 100 108 100 115 100 100 (physical property 15) tensile strength 100 100 101 100 100 100 102 100 103 102 (Physical Property 16) Processability into film 5 2 5 2 5 3 5 2 5 2 [Table 7] Implementation example 11 12 13 14 15 16 17 18 19 20 (physical property 11) Mooney viscosity of the composition 101 100 98 100 98 100 100 90 110 95 (physical property 12) Performance in snow 108 109 110 115 110 108 109 113 117 101 (physical property 13) Wet performance 108 109 105 115 110 110 108 112 118 100 (physical property 14) Friction resistance 101 102 100 100 100 100 100 105 97 100 (physical property 15) tensile strength 100 100 100 110 100 101 100 103 95 100 (Physical Property 16) Processability into film 5 2 5 5 5 5 5 5 5 5 [Table 8] Comparison example 1 2 3 4 5 6 7 8 9 (physical property 11) Mooney viscosity of the composition 100 98 98 100 99 96 112 102 101 (physical property 12) Performance in snow 100 98 95 98 95 100 100 93 103 (physical property 13) Wet performance 100 99 95 90 97 93 101 88 105 (physical property 14) Friction resistance 100 105 98 99 100 98 90 95 90 (physical property 15) tensile strength 100 100 98 97 100 99 90 99 89 (Physical Property 16) Processability into film 5 5 5 5 5 5 5 5 5

[0413] As shown in Tables 6 to 8, the modified conjugated diene polymer compositions of Working Examples 1 to 20 as vulcanizates are better than the modified conjugated diene polymer compositions of Comparative Examples 1 to 9 in terms of the balance between snow performance and wet performance and friction resistance. [Industrial applications]

[0414] The modified conjugated diene polymer compositions according to this invention have potential for industrial application in the fields of tire treads, interior and exterior accessories of automobiles, anti-vibration rubbers, belts, shoes, various industrial products, and the like.

Claims

[1] Modified conjugated diene polymer composition comprising a rubber component A comprising a modified conjugated diene polymer obtained by reacting a conjugated diene polymer with a nitrogen-containing compound and having a glass transition temperature of -35°C or higher, a rubber component B obtained by reacting a conjugated diene polymer with a nitrogen-containing compound and having a glass transition temperature of -55°C or lower, and silicon dioxide-containing filler, wherein the proportion of rubber component A in relation to the total amount of rubber component A and rubber component B is 50% by mass to 95% by mass, the rubber component A has a weight-average molecular weight of 20 × 10 4 up to 300 × 10 4 and has a molecular weight distribution Mw / Mn of 1.6 to 4.0, the degree of modification of the rubber component A, determined by a chromatogram obtained by gel permeation chromatography (GPC), is 50 mass% or higher, and the rubber component B is a modified conjugated diene polymer selected from a random copolymer of a conjugated diene compound and a vinyl aromatic compound, a hydrogenated product thereof, a block copolymer of a conjugated diene compound and a vinyl aromatic compound, and a hydrogenated product thereof. [2] The modified conjugated diene polymer composition according to claim 1, wherein the rubber component A is a rubber component in which the modification degree of the component having a molecular weight corresponding to half of the molecular weight at the peak top of the gel permeation chromatography (GPC) curve, or, when there are multiple peak tops, at the smallest peak top, determined by calculation from the chromatogram obtained by gel permeation chromatography GPC for determining the modification degree of the rubber component A, is half or more of the modification degree of the total amount of the rubber component A. [3] The modified conjugated diene polymer composition according to claim 1 or 2, wherein the modification degree of the rubber component A is 75 mass% or more and the nitrogen content is 25 mass ppm or more. [4] The modified conjugated diene polymer composition according to any one of claims 1 to 3, wherein the shrinkage factor (g') of the above-mentioned rubber component A determined by 3D-GPC is 0.70 or less. [5] The modified conjugated diene polymer composition according to any one of claims 1 to 4, wherein the rubber component B is a modified conjugated diene polymer in which the weight-average molecular weight is 20 × 10 4 up to 300 × 10 4, the molecular weight distribution Mw / Mn is 1.6 to 4.0, and the degree of modification, determined from a chromatogram obtained by gel permeation chromatography (GPC), is 50 mass% or higher, and in which the degree of modification of the component having a molecular weight corresponding to half the molecular weight at the peak tip of the gel permeation chromatography (GPC) curve, or, when multiple peak peaks are present, at the smallest peak tip, determined by calculation from the chromatogram obtained by gel permeation chromatography GPC for determining the degree of modification of the rubber component B, is half or more of the degree of modification of the total amount of the rubber component B. [6] A process for producing a modified conjugated diene polymer composition according to any one of claims 1 to 5, wherein the process for producing a modified conjugated diene polymer composition comprises a step of obtaining a mixture by mixing the above-mentioned rubber component B and the silica-containing filler, and a step of mixing the above-mentioned mixture and the above-mentioned rubber component A. [7] A vulcanized product obtained by using the modified conjugated diene polymer composition according to any one of claims 1 to 5. [8] The vulcanized product according to claim 7, wherein the vulcanized product is a tire.

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