RUBBER COMPOSITION, METHOD FOR PRODUCE A RUBBER COMPOSITION, VULCANIZED PRODUCT AND USE OF THE RUBBER COMPOSITION

Abstract

Rubber composition containing: (A) 100 parts by mass of a modified conjugated diene-based polymer obtained by reacting a conjugated diene-based polymer with a nitrogen-containing compound, wherein the weight-average molecular weight 20 × 10 4 or more and 300 × 10 4 or less and the molecular weight distribution Mw / Mn is 1.6 or more and 4.0 or less, wherein the modification rate in relation to the total amount of the conjugated diene-based polymer, as determined from a chromatogram obtained by gel permeation chromatography (GPC), is 50 wt% or more and the modification rate of a component with a molecular weight that is half the molecular weight at the peak tip in the chromatogram obtained by gel permeation chromatography (GPC) or, if multiple peak tips are present, at the peak tip with the minimum molecular weight, half or more of the modification rate with respect to the total amount of the conjugated diene-based polymer, (B) 10 to 250 parts by mass of natural rubber with a microgel content of 5 to 24% by mass and / or polyisoprene rubber with a 1,4-cis bonding quantity of 90% or more, as well as (C) 5 to 150 parts by mass of a filler containing silicon dioxide.

Description

[Technical field]

[0001] The present invention relates to a rubber composition containing a modified conjugated diene-based polymer, a process for producing the rubber composition, a vulcanized product, and the use of the rubber composition for producing a tire. [State of the art]

[0002] In recent years, requirements for low fuel consumption for automobiles have increased, improvements in materials used for car tires, especially tire treads in contact with the ground, and conventionally, the development of materials with low rolling resistance, i.e., with low hysteresis loss, has been required.

[0003] In order to reduce the weight of the tire, it is further necessary to reduce the thickness of the tread part of the tire, and moreover, a material with high wear resistance is also required.

[0004] In contrast, materials used for tire treads require excellent wet skid resistance and practically sufficient fracture properties for safety reasons.

[0005] As a material that meets such requirements, there are materials that contain rubber-like polymer and reinforcing filler such as carbon black or silicon dioxide.

[0006] When materials containing silica are used, an improvement in the balance between low hysteresis loss and wet skid resistance can be achieved.

[0007] Attempts are also being made to improve the dispersibility of silica in materials by introducing a functional group with affinity or reactivity with silica into the molecular end of a high-mobility conjugated diene-based polymer. Attempts are also being made to reduce hysteresis loss by reducing the mobility of the molecular end of the rubbery polymer by bonding it to the silica particle.

[0008] For example, WO 2016 / 133154 A1 proposes a modified conjugated diene-based polymer having a specific coupling group and a conjugated diene-based polymer chain of more than a predetermined number bonded to the coupling group, wherein the weight-average molecular weight is within a specific range, the modified conjugated diene-based polymer within the specific molecular weight range is contained in the amount of the specific range, excellent processability is obtained when used as a vulcanizate, and when used as a vulcanizate, it excels in the balance between low hysteresis loss and wet skid resistance.

[0009] WO 2018 / 164053 A1 or EP 3 594 251 A1 discloses rubber compositions containing a modified conjugated diene-based polymer and fillers, wherein other polymers may optionally be included, such as natural rubber and polyisoprene rubber. [Overview of the invention][Problem to be solved by the invention]

[0010] However, in a silica-containing rubbery conjugated diene-based polymer, since silica has a hydrophilic surface while carbon black has a hydrophobic surface, there is a disadvantage in that the affinity with the rubbery conjugated diene-based polymer is low and the dispersibility is poor compared to carbon black. Therefore, in the silica-containing rubbery conjugated diene-based polymer, it is necessary to separately contain a silane coupling agent or the like to impart a bond between the silica and the rubber and improve dispersibility.

[0011] In contrast, in a rubber-like conjugated diene-based polymer in which a highly reactive functional group with silica is introduced at the molecular end of the rubber, the reaction with the silica particles proceeds rapidly during the kneading step. However, there is the problem that if the reaction proceeds slowly, increasing the torque requires time, resulting in insufficient kneading, roughening during sheet processing after kneading, or easy cutting of the sheet, thus tending to deteriorate the processability.

[0012] When such a rubbery conjugated diene-based polymer is used as a vulcanizate, especially as a vulcanizate containing an inorganic filler such as silica, there is a problem that there is still room for improvement in the balance between low hysteresis loss and wet skid resistance, wear resistance, and fracture strength.

[0013] Therefore, the present invention has for its object to provide a modified conjugated diene-based polymer composition which can obtain a rubber composition which has good workability, particularly when kneading with the filler, the torque of the mixer is applied well, the dispersibility of the filler in a short time is good, and which is excellent in the balance between low hysteresis loss and wet skid resistance and also in durability such as wear resistance and fracture strength.

[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 a rubber composition containing a modified conjugated diene-based polymer in which a functional group having affinity or reactivity with a filler is introduced into a molecule of the conjugated diene-based polymer, (B) a natural rubber and / or polyisoprene rubber, and (C) a silica-containing filler, wherein, with respect to the modified conjugated diene-based polymer, the weight-average molecular weight and the molecular weight distribution are within a certain range and the modification rate is within a certain range, and the modification rate of a component(s) (hereinafter referred to as "components")referred to as a low molecular weight component) having a molecular weight that is half of the molecular weight at the peak top in a molecular weight curve by GPC (gel permeation chromatography) compared to the modification rate of the entire modified conjugated diene-based polymer is a predetermined value or more, can solve the above-mentioned problems of the prior art, and arrive at the present invention.

[0015] The present invention is set out in the appended claims. [Effects of the invention]

[0016] According to the present invention, there can be provided a rubber composition containing a modified conjugated diene-based polymer, which exhibits excellent workability when used as a vulcanizate, particularly when kneading with the filler, the torque of the mixer is well applied, the dispersibility of the filler in a short time is good, and which excels in the balance between low hysteresis loss and wet skid resistance and also in durability such as wear resistance and fracture strength when used as a vulcanizate. [Embodiments of the invention]

[0017] Hereinafter, an embodiment of the present invention (hereinafter referred to as "present embodiment") will be described in detail.

[0018] The following embodiments serve to illustrate the present invention and are not intended to limit the present invention to the following contents. The present invention can be implemented with appropriate modifications within the scope of the invention. [Rubber composition containing modified conjugated diene-based polymer]

[0019] The modified conjugated diene-based polymer-containing rubber composition of the present embodiment contains: (A) 100 parts by mass of a modified conjugated diene-based polymer in which the weight-average molecular weight 20 × 10 4 or more and 300 × 10 4 or less and the molecular weight distribution Mw / Mn is 1.6 or more and 4.0 or less, wherein the modification rate with respect to the total amount of the conjugated diene-based polymer is 50 mass% or more, and the modification rate of components having a molecular weight that is half the molecular weight at the peak tip in a gel permeation chromatography (GPC) curve or, when multiple peaks are present, at the peak tip with the minimum molecular weight, is half or more of the modification rate with respect to the total amount of the conjugated diene-based polymer, (B) 10 to 250 parts by mass of natural rubber having a microgel content of 4 to 24 mass% and / or polyisoprene rubber having a 1,4-cis bond amount of 90% or more, and (C) 5 to 150 parts by mass of a silicon dioxide-containing filler. ((A) Modified conjugated diene-based polymer)

[0020] Regarding the (A) modified conjugated diene-based polymer, the weight-average molecular weight 20 × 10 4 or more and 300 × 10 4 or less and the molecular weight distribution Mw / Mn 1.6 or more and 4.0 or less, where the modification rate with respect to the total amount of the conjugated diene-based polymer is 50 mass% or more, and the modification rate of the component (hereinafter referred to as the low molecular weight component if necessary) having the molecular weight that is half of the molecular weight at the peak top in a gel permeation chromatography (GPC) curve or, when multiple peak tops are present, at the peak top with the minimum molecular weight, is half or more of the modification rate with respect to the total amount of the conjugated diene-based polymer. <modifizierungsrate>

[0021] Regarding the (A) modified conjugated diene-based polymer, the modification rate with respect to the total amount of the conjugated diene-based polymer is 50 mass% or more, preferably 60 mass% or more, and more preferably 70 mass% or more.

[0022] When the modification rate is 50 mass% or more and thus it is used as a vulcanizate, the balance between low hysteresis loss and wet skid resistance is excellent.

[0023] The modification rate represents the content of the polymer component having a specific functional group with affinity or binding reactivity for the filler in the polymer molecule with respect to the total amount of the conjugated diene-based polymer in mass%.

[0024] Examples of polymer components having a specific functional group with affinity or binding reactivity for the filler in the polymer molecule preferably include a polymer having a functional group containing a nitrogen atom, a silicon atom, or an oxygen atom. The modified conjugated diene-based polymer according to the invention is obtained by reacting a conjugated diene-based polymer with a nitrogen-containing compound. More preferably, it is a modified conjugated diene-based polymer having the functional group at the end of the polymer.

[0025] The modification rate of the (A) modified conjugated diene-based polymer can be measured by chromatography, which can separate the modified components containing a functional group from the unmodified components. Examples of methods using this chromatography include a quantification method using a gel permeation chromatography column with a polar substance such as silica that adsorbs a specific functional group as a filler and using the internal standard of the non-adsorbing component for comparison.

[0026] Specifically, the modification rate can be calculated by calculating the difference between the chromatogram measured by a polystyrene gel column for the sample solution containing the measurement sample and the internal standard low-molecular-weight polystyrene and the chromatogram measured by a silica column, and by measuring the adsorption amount of the silica column. The modification rate can be measured by the method described in the later working examples.

[0027] The modification rate of the (A) modified conjugated diene-based polymer can be controlled to the above numerical range by adjusting the addition amount of the modifier. <Modifizierungsrate der Komponente mit niedrigem Molekulargewicht>

[0028] By measuring the modification rate in each molecular weight range in the molecular weight curve by GPC, the present inventors found that the modification rate for each molecular weight range differs depending on the polymer.

[0029] It was further found that the modified conjugated diene-based polymer in which the modification rate of component (low molecular weight component) having the molecular weight that is half of the molecular weight at the peak top of the GPC curve is half or more of the modification rate of the entire modified conjugated diene-based polymer is excellent in certain properties compared with a modified conjugated diene-based polymer in which the modification rate is uneven and, in particular, the modification rate of the low molecular weight component is lower than half of the modification rate of the entire modified conjugated diene-based polymer.

[0030] Regarding the (A) modified conjugated diene-based polymer, the modification rate of the component (low molecular weight component) with a molecular weight that is half the molecular weight when a single peak is present on the GPC curve, or at the peak peak with the minimum molecular weight when multiple peaks are present, is half or more of the modification rate with respect to the total amount of the conjugated diene-based polymer. It is preferably 0.55 or more, and more preferably 0.57 or more.

[0031] By this, (A) a modified conjugated diene-based polymer can be obtained in which excellent processability is obtained, and particularly in the kneading with the filler, the torque of the mixer is well applied, and a rubber composition having good dispersibility of the filler is obtained in a shorter time than conventional.

[0032] Further, when the modified conjugated diene-based polymer composition of the present embodiment is used as a vulcanized composition, the degree of freedom of composition design is increased, which serves to obtain a rubber composition excellent in the balance between low hysteresis loss and wet skid resistance and also in fracture strength and wear resistance, and particularly in low hysteresis loss as for tires.

[0033] As described above, in addition to discovering that the modification rate is different for each molecular weight range depending on the polymer, the inventors found a following mechanism as a method for transmitting the torque when kneading the polymer with the filler, thereby completing the present invention. That is, if attention is first paid to the modification rate of the modified conjugated diene-based polymer with respect to the total amount of the conjugated diene-based polymer, for a polymer in which the modification rate with respect to the total amount of the conjugated diene-based polymer is high (modification rate of 50% or more) when the Mooney viscosity, microstructure, modifier used, kneading conditions, etc. of the polymer are the same, compared with a polymer with a low modification rate, the rate of torque increase during kneading with the filler is high, but the maximum value that the torque reaches is also high, so the time required for the torque to reach the maximum value is substantially the same even if the total modification rate changes. That is,The modification rate of the entire polymer influences both the maximum torque value and the rate of torque increase, so it is assumed that no major influence is exerted on the length of time required to reach the maximum torque value.

[0034] In contrast, when considering the modification rate of the low-molecular-weight component, that is, the modification rate of the component with a molecular weight half of the peak molecular weight, the rate of torque increase during kneading the polymer with the filler becomes lower the lower the modification rate of the low-molecular-weight component relative to the modification rate of the total amount of the conjugated diene-based polymer. The higher the modification rate of the low-molecular-weight component relative to the modification rate of the total amount of the conjugated diene-based polymer, the higher the torque increase rate becomes.

[0035] As described above, the rate of torque increase is also influenced by the modification rate relative to the total amount of the conjugated diene-based polymer. For both high and low "modification rate relative to the total amount of the conjugated diene-based polymer," the rate of torque increase is increased when the "modification rate of the low molecular weight component" is high.

[0036] That is, according to the present inventors' review, the influence of the magnitude of the "modification rate of the low molecular weight component" with respect to the "modification rate with respect to the total amount of the conjugated diene-based polymer" on the torque increase rate is independent of the "modification rate with respect to the total amount of the conjugated diene-based polymer" and constant.

[0037] In contrast, since the maximum torque value is determined depending on the modification rate of the entire modified conjugated diene-based polymer, it does not change depending on the modification rate of the low-molecular-weight component. That is, it does not depend on the modification rate of the low-molecular-weight component. Therefore, the higher the modification rate of the low-molecular-weight component, the shorter the time to reach the maximum torque value. Therefore, the time to reach the maximum torque value can be controlled regardless of the modification rate with respect to the total amount of the conjugated diene-based polymer and depending on the magnitude of the modification rate of the low-molecular-weight component with respect to the modification rate with respect to the total amount of the conjugated diene-based polymer.

[0038] Specifically, by setting the modification rate of the low molecular weight component to half or more of the modification rate relative to the total amount of the conjugated diene-based polymer, the processability is improved, especially the mixer torque during kneading with the filler is well applied, and the filler dispersibility in a shorter time is improved. As a result, it is possible to minimize the heat deterioration that occurs in the polymer during kneading and reduce the amount of heat stabilizer to be mixed, since heat deterioration is difficult.

[0039] Further, by making the modification rate of the low molecular weight component half or more of the modification rate with respect to the total amount of the conjugated diene-based polymer, when the (A) modified conjugated diene-based polymer is used as a vulcanized composition, the degree of freedom of composition design is increased, which serves to obtain a rubber composition excellent in the balance between low hysteresis loss and wet skid resistance and also in fracture strength and wear resistance, and particularly in low hysteresis loss as for tires.

[0040] To increase low hysteresis loss in the production of a rubber composition for a tire, it is effective to use a modified conjugated diene-based polymer with a higher branching degree and / or a higher molecular weight. However, processing problems such as difficulty in kneading with a filler or the like may occur. For such problems, a technique for improving the processability of the modified conjugated diene-based polymer is used to prevent problems such as those in the kneading step, even when the (A) modified conjugated diene-based polymer with a higher branching degree and / or high molecular weight is used, and as a result, a composition more suitable for the tire can be easily produced.

[0041] From this point of view, with respect to the (A) modified conjugated diene-based polymer, it is assumed that the modification rate of component having the molecular weight which is half of the molecular weight at the peak top in the GPC curve is half or more of the modification rate with respect to the total amount of the conjugated diene-based polymer.

[0042] The (A) modified conjugated diene-based polymer can be obtained by a polymerization process in which the termination of the growth reaction or the chain transfer is extremely low, and therefore, by an ultra-high purity of monomers and solvents introduced into the polymerization reactor, polymerization at low temperature and with a monomer conversion of less than 99 mass% can be achieved.

[0043] The modification rate for each molecular weight component can be measured by chromatography, which can separate the modified components containing a functional group from the unmodified components. Examples of methods using this chromatography include a quantification method using a gel permeation chromatography column with a polar substance such as silica that adsorbs a specific functional group as a filler and using the internal standard of the non-adsorbing component for comparison.

[0044] Specifically, the modification rate for each molecular weight component is obtained by calculating the adsorption amount on the silica column from the difference for each molecular weight component between the chromatogram measured for the sample solution containing the measurement sample and the internal standard low-molecular-weight polystyrene using a polystyrene gel column and the chromatogram measured using a silica column. The modification rate can also be measured by the method described in the later embodiments.

[0045] In order to make the modification rate of component having the molecular weight half of the molecular weight at the peak top in the GPC curve half or more of the modification rate with respect to the total amount of the conjugated diene-based polymer, it is effective, as described above, to increase the purity of the monomer and solvent introduced into the reactor and reduce the amount of the end deactivated during polymerization. <Gewichtsmittlere Molekulargewicht >

[0046] Regarding the (A) modified conjugated diene-based polymer, the weight-average molecular weight is 20 × 10 4 or more and 300 × 10 4 or less, preferably 30 × 10 4 or more and 270 × 10 4 or less, more preferably 40 × 10 4 or more and 250 × 10 4 or less and more preferably 50 × 10 4 or more and 250 × 10 4 or less.

[0047] If the high molecular weight, ie the weight average molecular weight 50 × 10 4 or more, the addition amount of the polymerization initiator to be used decreases, so that the influence of growth reaction completion or chain transfer on the modification rate of the component having a molecular weight half of the peak molecular weight in the GPC curve is increased. For this reason, a modified conjugated diene-based polymer with a desired modification rate is difficult to obtain unless ultra-high purity of monomers and solvents introduced into the polymerization reactor, low-temperature polymerization, and a monomer conversion of less than 99 mass% are achieved. Although the manufacturing conditions become difficult, the modified conjugated diene-based polymer excels in wear resistance when used as a vulcanizate by setting the weight-average molecular weight within the above range.

[0048] In the (A) modified conjugated diene-based polymer constituting the modified conjugated diene-based polymer composition of the present embodiment, the production conditions are preferably controlled to increase the modification rate of the low molecular weight component while keeping the molecular weight high to improve the properties.

[0049] By using the weight average molecular weight of 20 × 10 4 or more and 300 × 10 4 or less, an excellent balance between low hysteresis loss and wet skid resistance as well as excellent wear resistance when used as a vulcanizate are obtained.

[0050] By using a weight-average molecular weight of 300 × 10 4 or less, excellent filler dispersibility and excellent fracture strength are further obtained when used as a vulcanizate.

[0051] The weight-average molecular weight of the (A) modified conjugated diene-based polymer can be measured by the method described in the later-described working examples. <molekulargewichtsverteilung>

[0052] Regarding the (A) modified conjugated diene-based polymer, the molecular weight distribution Mw / Mn, represented by the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn), is 1.6 or more and 4.0 or less. The (A) modified conjugated diene-based polymer having a molecular weight distribution in this range tends to excel in processability compared to a polymer with the same molecular weight and the same modification rate when used as a vulcanizate. It is preferably 1.8 or more and 3.0 or less, and more preferably 1.9 or more and 2.5 or less.

[0053] The (A) modified conjugated diene-based polymer having such molecular weight distribution can preferably be obtained by continuous polymerization.

[0054] The molecular weight distribution is preferably monomodal in the molecular weight curve obtained by GPC, or trapezoidal or continuous in the case of multiple peaks. Continuous means a shape in which the lowest height between the peaks is 50% or more of the peak heights on both sides. The (A) modified conjugated diene-based polymer with such a molecular weight distribution tends to exhibit excellent processability when used as a vulcanizate.

[0055] The (A) modified conjugated diene-based polymer preferably contains 0.3 mass% or more and 20 mass% or less of the modified conjugated diene-based polymer having a molecular weight of 2,000,000 to 5,000,000 (hereinafter also referred to as "specific high molecular weight component"). This tends to be excellent in the balance between low hysteresis loss and wet skid resistance, as well as in the wear resistance, when used as a vulcanizate.

[0056] The content of the specific high molecular weight component is more preferably 1.0 mass% or more and 18 mass% or less, and even more preferably 2.0 mass% or more and 15 mass% or less.

[0057] To obtain a (A) modified conjugated diene-based polymer in which the content of the specific high-molecular-weight component is within such a range, for example, the use amount of an organic monolithium compound described later as a polymerization initiator can be adjusted. In a polymerization step described later, it is preferable to select a method with a residence time distribution, that is, a method for broadening the time distribution of the growth reaction, regardless of whether the polymerization process is a continuous type or a batch type.

[0058] Examples of concrete methods in the continuous type include: a backmixed reactor method using a tank reactor with a stirring machine in which vigorous mixing is carried out with the stirring machine, preferably a method used as a complete mixing reactor, a method of recirculating a portion in a tubular reactor, a method of providing an inlet of the polymerization initiator at or near the monomer inlet or at the intermediate point of the polymerization vessel as a feed site, and a method combining a tank type reactor and a tubular type reactor.

[0059] According to these methods, the residence time distribution can be increased, and a polymer component with a long residence time can be used as a high molecular weight component.

[0060] Examples of specific batch-type processes include, for example, a process for continuously or intermittently supplying the polymerization initiator from the beginning to the middle of the polymerization.

[0061] According to this method, the polymer polymerized from the polymerization starting point when the polymerization initiator is added first becomes a high-molecular-weight component, and a difference in molecular weight from a later-polymerized polymer occurs. Specifically, when the amount of polymerization initiator corresponding to the target molecular weight is continuously added to the monomer, for example, at a conversion rate of 0 to 95 mass%, a polymer with a broad molecular weight distribution can be obtained.

[0062] Using the method described above, the activity ratio of the living end of the conjugated diene-based polymer tends to be high before the reaction step, and a modified conjugated diene-based polymer with a high coupling rate after the coupling, i.e., a high modification rate, is obtained. Among these methods, a method using a tank reactor with a stirrer is more preferable, in which vigorous mixing with the stirrer takes place.

[0063] In this specification, the "molecular weight" is a molecular weight converted to standard polystyrene obtained by GPC (gel permeation chromatography).

[0064] The number average molecular weight, the weight average molecular weight and the molecular weight distribution can be measured by the method described in the working examples described later. <schrumpffaktor>

[0065] The (A) modified conjugated diene-based polymer includes, as a preferred form, a modified conjugated diene-based polymer in which the shrinkage factor (g') measured by 3D-GPC is 0.86 or more and 1.0 or less.

[0066] By keeping the shrinkage factor (g') of the (A) modified conjugated diene-based polymer within the above range, the strength at high temperature tends to be excellent.

[0067] The shrinkage factor (g') serves as an index of the branched structures of (A) the modified conjugated diene-based copolymer, and the modified conjugated diene-based polymer having a shrinkage factor (g') of 0.86 or more and 1.0 or less is generally a modified conjugated diene-based polymer having three or fewer branches in one molecule of the modified conjugated diene-based polymer. In this case, the shrinkage factor (g') is preferably 0.88 or more and 0.99 or less, and more preferably 0.90 or more and 0.98 or less.

[0068] In order to obtain the (A) modified conjugated diene-based copolymer, a method of obtaining (A) a modified conjugated diene-based copolymer having three or fewer branches by adding a modifier having three or fewer reaction points with the living active terminal in a mole number of 1 / 3 or more to the total mole number of the polymerization initiator is effective.

[0069] The (A) modified conjugated diene-based polymer includes, as a preferred form, a polymer in which the shrinkage factor (g') measured by 3D-GPC is 0.30 or more and less than 0.86.

[0070] Such (A) modified conjugated diene-based polymer has a greatly reduced viscosity of the composition to which the filler is added and has excellent processability.

[0071] The shrinkage factor (g') serves as an index for the branched structures of the (A) modified conjugated diene-based copolymer, and the (A) modified conjugated diene-based polymer having a shrinkage factor (g') of 0.30 or more and less than 0.86 is a modified conjugated diene-based polymer in which the number of branches in one molecule of the modified conjugated diene-based polymer is four or more.

[0072] In order to obtain the (A) modified conjugated diene-based copolymer, a method of obtaining a (A) modified conjugated diene-based copolymer having four or more branches by adding a modifier having four or more reaction points with the living active terminal in a mole number of 1 / 4 or less to the total mole number of the polymerization initiator is effective.

[0073] Regarding the (A) modified conjugated diene-based polymer, the shrinkage factor (g') measured using 3D-GPC is more preferably 0.30 or more and 0.70 or less.

[0074] Such (A) modified conjugated diene-based polymer has a lower viscosity of the composition to which the filler is added and has excellent processability.

[0075] The shrinkage factor (g') serves as an index for the branched structures of the (A) modified conjugated diene-based copolymer, and the (A) modified conjugated diene-based polymer having a shrinkage factor (g') of 0.30 or more and 0.70 or less is a (A) modified conjugated diene-based polymer in which the number of branches in one molecule of the modified conjugated diene-based polymer is five or more.

[0076] In order to obtain the (A) modified conjugated diene-based copolymer, a method of obtaining a (A) modified conjugated diene-based copolymer having five or more branches by adding a modifier having five or more reaction points with the living active terminal in a mole number of 1 / 5 or less to the total mole number of the polymerization initiator is effective.

[0077] The shrinkage factor (g') measured by GPC light scattering measurement with a viscosity detector (hereinafter also referred to simply as "GPC light scattering measurement with viscosity detector" or "3D GPC measurement") serves as an index of the number of branches of the modified conjugated diene-based polymer. For example, as the shrinkage factor (g') decreases, the number of branches of the (A) modified conjugated diene-based polymer tends to increase (e.g., the number of branches of the star polymer (also referred to as the "number of arms of the star polymer")).

[0078] When comparing modified conjugated diene-based polymers with the same absolute molecular weight, the shrinkage factor (g') decreases with increasing number of branches of the (A) modified conjugated diene-based polymer. Therefore, in this case, the shrinkage factor (g') can be used as an index of the number of branches.

[0079] The shrinkage factor (g') is measured using 3D GPC. The constant (K, α) in the relationship ([η] = KMα ([η]: intrinsic viscosity, M: molecular weight)) between intrinsic viscosity and molecular weight is defined as logK = -3.883, α = 0.771, and the molecular weight M is input in a range of 1000 to 20000000 to establish the relationship between the standard intrinsic viscosity [η]0 and the molecular weight M.

[0080] With respect to this intrinsic standard viscosity [η]0, the intrinsic viscosity [η] at each molecular weight M of the sample obtained by 3D GPC measurement, i.e., the relationship [η] / [η]0 of the intrinsic viscosity [η] to the intrinsic standard viscosity [η]0 for each molecular weight M is determined, and the average value is defined as the shrinkage factor (g').

[0081] Specifically, it can be measured by the method described in the embodiments described later. <Ausbildung des (A) modifizierten konjugierten Dien-basierten Polymers>

[0082] The (A) modified conjugated diene-based polymer may have a branched structure.

[0083] There can be one branch point or multiple branch points in a polymer.

[0084] The (A) modified conjugated diene-based polymer is preferably a modified conjugated diene-based polymer having a functional group having an affinity or reactivity for the filler in the polymerization initiator moiety and / or the modifier moiety.

[0085] That is, the (A) modified conjugated diene-based polymer preferably consists of a polymerization initiator residue and / or a modifier residue having a functional group and a conjugated diene-based polymer chain.

[0086] It is preferable that the polymerization initiator residue does not contain nitrogen. When the polymerization initiator residue contains nitrogen, the final processability when used as a vulcanizate is the same, but the reaction with the filler tends to be rapid, and the processability of the film in the initial stage of multi-stage kneading is impaired. In contrast, when the polymerization initiator residue does not contain nitrogen, it reacts with the filler at an appropriate rate, so the processability of the film is good even in the initial stage of multi-stage kneading. <modifikatorrest>

[0087] The modifier moiety in the (A) modified conjugated diene-based polymer is a component unit of the modified conjugated diene-based polymer bonded to the conjugated diene-based polymer chain, for example, a structural unit derived from a modifier produced by reacting a later-described modified conjugated diene-based polymer with the modifier.

[0088] The modifier moiety has a specific functional group with affinity or binding reactivity with the filler.

[0089] When the (A) modified conjugated diene-based polymer is a modified conjugated diene-based polymer in which a functional group is bonded to the polymerization initiation terminal, the (A) modified conjugated diene-based polymer can be obtained by a polymerization reaction using the polymerization initiator having a functional group. <ende>

[0090] When the (A) modified conjugated diene-based polymer does not have a branched structure, the (A) modified conjugated diene-based polymer has a straight chain structure, and the "end" means the two ends of the straight chain, one of which is bonded to the modifier residue and the other to the polymerization initiator residue.

[0091] When the (A) modified conjugated diene-based polymer has a branched structure and at least one of the branching points is a modifier group, the "terminal" in the (A) modified conjugated diene-based polymer means an end of the conjugated diene-based polymer chain that is not bonded to the branching point, e.g., the "modifier group." Such a modified conjugated diene-based polymer is obtained by first polymerizing a monomer using a polymerization initiator and then bonding a modifier to the terminal end of the polymerization to form a branching point. In this case, the modified conjugated diene-based polymer has a polymerization initiator group at the end of the polymer chain that is not bonded to the modifier group.

[0092] When the (A) modified conjugated diene-based polymer has a branched structure and does not have a branching point through the modifier group, the "terminal" in the (A) modified conjugated diene-based polymer is an end of the conjugated diene-based polymer chain that is not bonded at the branching point and has a modifier group or a polymerization initiator group. <Bevorzugte Ausführungsform bezüglich der funktionellen Gruppe>

[0093] According to the invention, a functional group containing a nitrogen atom and optionally silicon is used as a specific functional group having affinity or binding reactivity with the filler.

[0094] The ratio of the number of moles of nitrogen atoms to the number of moles of silicon atoms, i.e. the number of moles of N / Si, is preferably 0.1 to 10.0 and more preferably 0.2 to 7.0.

[0095] In this range, the affinity to the silica filler is particularly good, the hysteresis loss of the rubber composition using the silica filler is small, and good performance is exhibited as a rubber composition for the fuel-efficient tire.

[0096] Examples of functional groups containing a nitrogen atom include, but are not limited to, a secondary amino group and a tertiary amino group.

[0097] The (A) modified conjugated diene-based polymer is a modified conjugated diene-based polymer having a functional group containing a nitrogen atom in the polymer molecule. The functional group containing a nitrogen atom is preferably one in which the nitrogen atom contains at least one -NH- type secondary amine. In this case, the hysteresis loss of the rubber composition using silica filler and carbon black as the filler is low, and good performance is exhibited as a composition for a fuel-efficient tire. <Monomer, das das konjugierte Dien-basierte Polymer bildet>

[0098] The (A) conjugated diene-based polymer before modification of the modified conjugated diene-based polymer is obtained by polymerizing at least one conjugated diene compound, and, as needed, both a conjugated diene compound and an aromatic vinyl compound are copolymerized.

[0099] The conjugated diene compound is not particularly limited as long as it is a polymerizable monomer, but a conjugated diene compound having 4 to 12 carbon atoms per molecule is preferred, and a conjugated diene compound having 4 to 8 carbon atoms is more preferred. 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, and 1,3-heptadiene. Among them, 1,3-butadiene and isoprene are preferred in view of industrial availability. These can be used alone or in combination of two or more.

[0100] The aromatic vinyl compound is not particularly limited as long as it is a monomer copolymerizable with a conjugated diene compound, however, a monovinyl aromatic compound is preferred. Examples of monovinyl aromatic compounds include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among them, styrene is preferred in view of industrial availability. These can be used alone or in combination with two or more. <Bevorzugte Ausführungsform im Fall von SBR>

[0101] When the (A) modified conjugated diene-based polymer is a butadiene-styrene random copolymer (SBR), the amount of bound styrene is preferably 5 mass% to 50 mass%, and the vinyl content is preferably 10 mol% to 75 mol%. When the amount and content are within this range, industrially produced SBR is obtained, which can be adapted not only for tires but also for all applications.

[0102] In particular, when the amount of bound styrene is 25 mass% to 45 mass% and the vinyl content is 18 mass% to 30 mass%, a rubber composition with low hysteresis loss and excellent wear resistance can be obtained.

[0103] Furthermore, when the amount of bound styrene is 18 to 28 mass% and the vinyl content is 45 to 65 mass%, a rubber composition blended with a natural rubber having a low hysteresis loss and excellent strength for fuel-efficient tires can be obtained.

[0104] The amount of bound styrene is mass% of styrene in all monomer components and the vinyl content is mass% of vinyl bonding components in the butadiene component. <Glasübergangstemperatur>

[0105] The glass transition temperature of the (A) modified conjugated diene-based polymer, i.e., Tg, is the temperature at which the molecular chain of the (A) modified conjugated diene-based polymer starts to rotate, and exerts a great influence on low hysteresis loss and wet skid resistance.

[0106] When the Tg is low, the hysteresis loss is good and when the Tg is high, the wet skid resistance is improved.

[0107] The (A) modified conjugated diene-based polymer preferably comprises a polymer with a Tg of -20°C or higher and 0°C or lower. This results in excellent wet skid resistance and rigidity. This modified conjugated diene-based polymer is extremely useful for high-performance and ultra-high-performance tires.

[0108] Furthermore, (A) modified conjugated diene-based polymer includes the polymer with a Tg of -50°C or higher and lower than -20°C as another preferred form. This provides an excellent balance between low hysteresis loss and wet skid resistance. This modified conjugated diene-based polymer is extremely useful for summer tires and all-season tires.

[0109] Additionally, the (A) modified conjugated diene-based polymer includes the polymer with a Tg of -70°C or higher and lower than -50°C as another preferred form. This provides excellent low-temperature performance and wear resistance.

[0110] This (A) modified conjugated diene-based polymer is extremely useful for winter tires.

[0111] This (A) modified conjugated diene-based polymer is further used for blending various tire treads to improve wear resistance.

[0112] The Tg of the modified conjugated diene-based polymer can be measured according to ISO 22768: 2006.

[0113] The Tg of the (A) modified conjugated diene-based polymer can be controlled to the numerical ranges described above by adjusting the amount of bound styrene and the vinyl content. <Bevorzugte Form im Fall von Random-SBR>

[0114] When the (A) modified conjugated diene-based polymer is a butadiene-styrene random copolymer (SBR), it is preferable that the proportion of styrene units present alone is large, and those with few long chains are preferable.

[0115] Specifically, when the (A) modified conjugated diene-based polymer is a butadiene-styrene copolymer, the copolymer is decomposed by the ozonolysis method known as the method of Tanaka et al. (Polymer, 22, 1721 (1981)). When the styrene chain distribution is analyzed by GPC, the content of isolated styrene is 40 mass% or more based on the total amount of bound styrene, and the chain styrene structure with a number of styrene chains of 8 or more is preferably 5 mass% or less. In this case, a rubber composition for fuel-efficient tires with excellent performance is obtained, in which the hysteresis loss of the resulting vulcanized rubber can be reduced. <Hydriertes konjugiertes Dien-basiertes Polymer>

[0116] The (A) modified conjugated diene-based polymer is obtained by subjecting the (A) modified conjugated diene-based polymer or the conjugated diene-based polymer to hydrogenation in an inactive solvent prior to modification. This can convert all or part of the double bond into a saturated hydrocarbon. In this case, heat resistance and weather resistance are improved, the product can be prevented from deteriorating when processed at high temperatures, and the kinematic performance as a rubber tends to improve. As a result, even better performance is achieved in various applications, such as automotive applications.

[0117] The hydrogenation rate of the unsaturated double bond based on the conjugated diene compound can be arbitrarily selected depending on the purpose and is not particularly limited. When used as a vulcanizate, the double bond of the conjugated diene moiety preferably remains partially intact. From this point of view, the hydrogenation rate of the conjugated diene moiety in the conjugated diene-based polymer is preferably 3.0 mol% or more and 70 mol% or less, more preferably 5.0 mol% or more and 65 mol% or less, and even more preferably 10 mol% or more and 60 mol% or less. In particular, heat resistance and movement performance tend to be improved by selective hydrogenation of vinyl groups. The hydrogenation rate can be measured using a nuclear magnetic resonance (NMR) device. <Oil-extended polymer, Mooney viscosity>

[0118] The (A) modified conjugated diene-based polymer may be an oil-extended polymer to which an extender oil is added. The modified conjugated diene-based polymer may be non-oil-extended or oil-extended.

[0119] From the viewpoint of processability in producing a rubber vulcanizate and wear resistance when used as a vulcanizate, the (A) modified conjugated diene-based polymer has a Mooney viscosity measured at 100°C of 20 or more and 100 or less, and more preferably 30 or more and 80 or less. The Mooney viscosity can be measured by the method described in the later working examples. <stickstoff silizium-gehalt>

[0120] Regarding the (A) modified conjugated diene-based copolymer, the nitrogen and silicon content is preferably 3 ppm by mass or more, more preferably 7 ppm by mass or more, and even more preferably 10 ppm by mass or more, from the viewpoint of improving the low hysteresis loss.

[0121] It is assumed that the (A) modified conjugated diene-based copolymer is physically adsorbed by nitrogen when kneaded with a filler and chemically bonded by silicon.

[0122] In the (A) modified conjugated diene-based copolymer, the molar ratio between the resulting nitrogen and silicon is important, and from the viewpoint that silica particles can be dispersed in a short time upon kneading, it is preferable that the nitrogen to silicon molar ratio (N / Si) is 1.1 or more and less than 10, more preferably 1.3 or more and 7 or less, and even more preferably 1.5 or more and 5 or less. The reason why the N / Si molar ratio is preferably in the above range is estimated to be that physical adsorption by nitrogen with respect to silica particles has a higher reaction rate than chemical bonding by silicon, so the nitrogen to silicon molar ratio is preferably equimolar or more.

[0123] Furthermore, the (A) modified conjugated diene-based copolymer preferably comprises a polymer in which the molar ratio of nitrogen to silicon (N / Si) is 0.1 or more and less than 0.9. This tends to excel in wear resistance when used as a vulcanizate. In such a case, it is more preferably 0.2 or more and 0.75 or less, and even more preferably 0.3 or more and 0.6 or less.

[0124] Although the reason why the molar ratio of nitrogen to silicon is preferably 0.1 or more and less than 0.9 is unclear at this time, it is estimated that the chemical bonding of silicon to the silica particles is stronger than the physical adsorption of nitrogen, so when the molar ratio of nitrogen to silicon is less than equimolar, the proportion of a chemical bond between the modified conjugated diene-based polymer and silica is increased, and the bonding between the modified conjugated diene-based polymer and silica is strengthened. In this case, the silicon content is preferably 7 ppm or more.

[0125] The nitrogen and silicon content of the (A) modified conjugated diene-based copolymer and the molar ratio of nitrogen to silicon can be controlled by the modifier used in the modification reaction of the conjugated diene-based copolymer.

[0126] For example, it is possible to increase the molar ratio of nitrogen to silicon in the modified conjugated diene-based copolymer by increasing the molar ratio of nitrogen to silicon in the modifier. <Bevorzugte Struktur von (A) modifizierten konjugierten Dien-basierten Polymer>

[0127] The (A) modified conjugated diene-based polymer is preferably represented by the following general formula (I).

[0128] In formula (I), D1 represents a diene polymer chain, R 1 to R 3 each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, R 4 and R 7 each independently represents an alkyl group having 1 to 20 carbon atoms, R 5 , R 8 and R 9 each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, R 6 and R 10 each independently represents an alkylene group having 1 to 20 carbon atoms, and R 11 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

[0129] m and x represent an integer from 1 to 3, where x ≤ m, p represents 1 or 2, y represents an integer from 1 to 3, where y ≤ (p + 1), and z represents the integer of 1 or 2.

[0130] If several are present, D1, R 1 to R 11 , m, p, x, y and z are each independent.

[0131] i represents an integer from 0 to 6, j represents an integer from 0 to 6, k represents an integer from 0 to 6, (i + j + k) is an integer from 1 to 10, and ((x × i) + (y × j) + (z × k)) is an integer from 1 to 30.

[0132] A represents a hydrocarbon group having 1 to 20 carbon atoms or at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom, a silicon atom, a sulfur atom, and a phosphorus atom, and represents an organic group that does not contain active hydrogen. However, when (i + j + k) is 1, A may be absent. Therefore, the modified conjugated diene-based polymer tends to exhibit a balance between low hysteresis loss and wet skid resistance and wear resistance when used as a vulcanizate.

[0133] In the (A) modified conjugated diene-based polymer, A in the formula (I) preferably represents one of the following general formulas (II) to (V).

[0134] In formula (II) B 1 represents 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 are independent of each other if several B 1 are present.

[0135] In formula (III), B 2 a single bond or a hydrocarbon group with 1 to 20 carbon atoms, B 3 represents an alkyl group having 1 to 20 carbon atoms and a represents an integer from 1 to 10, where B 2 and B 3 are independent of each other if several B 2 and B 3 are present.

[0136] In formula (IV), B 4 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms and a represents an integer from 1 to 10, where B 4 are independent of each other if several B 4 are present.

[0137] In formula (V), B 5 represents 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 are independent of each other if several B 5 are present. This tends to make the modified conjugated diene-based polymer excel in balancing low hysteresis loss with wet skid resistance and wear resistance when used as a vulcanizate. It also tends to be readily available in practice. ((A) Process for producing a modified conjugated diene-based polymer)

[0138] The method for producing a (A) modified conjugated diene-based polymer comprises: a polymerization step in which an organic monolithium compound is preferably used as a polymerization initiator, at least one conjugated diene compound is polymerized to obtain conjugated diene-based polymer, and a modification reaction step in which the conjugated diene-based polymer and a modifier are reacted which has a bonding group which reacts with the active end of the conjugated diene-based polymer and further has a specific functional group having the affinity or bonding reactivity with the filler. <polymerisationsschritt>

[0139] In the process for producing the (A) conjugated diene-based polymer, an organic monolithium compound is preferably used as a polymerization initiator in the polymerization step, and at least one conjugated diene compound is polymerized to obtain a conjugated diene-based polymer.

[0140] In the polymerization step, polymerization is preferably carried out by a growth reaction through a living anionic polymerization, whereby there is a tendency that a conjugated diene-based polymer having an active terminal and a modified diene-based polymer having a high modification rate can be obtained.

[0141] Regarding the (A) modified conjugated diene-based polymer, the modification rate of the component (low molecular weight component) having the molecular weight half of the molecular weight at the peak top in the GPC curve is half or more of the modification rate with respect to the total amount of the conjugated diene-based polymer.

[0142] In order to obtain the (A) modified conjugated diene-based polymer, it is effective to obtain a conjugated diene-based polymer by a polymerization method in which the termination of the growth reaction or the chain transfer is extremely low.

[0143] Therefore, the ultra-high purification of monomers and solvents introduced into the polymerization reactor requires a higher standard than conventional.

[0144] Accordingly, the total amount of impurities in the monomer components used is preferably 30 ppm or less, and the content concentration (mass) of impurities such as allenes, acetylenes, primary and secondary amines is preferably 20 ppm or less, more preferably 10 ppm or less, and the acetylene is preferably 20 ppm or less, more preferably 10 ppm or less, primary or secondary amine as the total nitrogen content is preferably 4 ppm or less, more preferably 2 ppm or less.

[0145] Examples of allenes include, but are not limited to, propadiene and 1,2-butadiene. Examples of acetylenes include, but are not limited to, ethylacetylene and vinylacetylene. Examples of primary and secondary amines include, but are not limited to, methylamine and dimethylamine.

[0146] Ultra-high purification of the monomer and solvent can be achieved by sufficiently purifying all the monomer and solvent used for polymerization.

[0147] When purifying butadiene as a monomer, it is important not only to remove the polymerization inhibitor, but also to remove dimethylamine, N-methyl-γ-aminobutyric acid, etc., which can adversely affect anionic polymerization. Examples of methods for removing these include a method in which 1,3-butadiene containing a polymerization inhibitor is washed using low-oxygen water with an oxygen concentration of less than 2 mg / L as wash water, and then the polymerization inhibitor in 1,3-butadiene is removed.

[0148] When purifying styrene, which is a monomer, it is important to remove phenylacetylenes, etc., which can adversely affect anionic polymerization. Examples of methods for removing phenylacetylenes include a method of conducting a hydrogenation reaction using a palladium-supporting alumina catalyst.

[0149] When purifying normal hexane, which is a polymerization solvent, it is important to remove moisture, which can adversely affect anionic polymerization. Examples of methods for removing it include a method using γ-alumina and synthetic zeolite. Among them, a method using a synthetic zeolite is preferred, and the synthetic zeolite preferably has a large pore diameter, more preferably a pore diameter of 0.35 nm or more, and even more preferably 0.42 nm or more.

[0150] The ultra-high purification treatment required to obtain a preferred impurity concentration depends on the condition before the treatment, so it is preferable to measure the impurity concentration of the monomer and solvent before the polymerization reaction after the ultra-high purification treatment of the monomer and solvent.

[0151] If the desired impurity concentration of monomer and / or solvent is not obtained despite performing the above various processes, it is conceivable that some treatment was insufficient. When the amount of primary and secondary amines is to be reduced, the purification of butadiene is insufficient, so it is preferable to wash again with low-oxygen water having an oxygen concentration of less than 2 mg / L as wash water. When acetylenes are to be reduced, the purification of styrene is insufficient, so it is preferable to conduct a hydrogenation reaction again using, for example, a palladium-supporting alumina catalyst. In this case, it is preferable to increase the amount of the palladium-supporting alumina catalyst or the contact time with the palladium-supporting alumina catalyst.

[0152] As a polymerization process with very low growth reaction termination or chain transfer, controlling the polymerization temperature and monomer addition rate is effective.

[0153] The polymerization temperature is preferably a temperature at which the living anionic polymerization proceeds, and from the viewpoint of productivity, it is preferably 0°C or more, and preferably 80°C or less. More preferably, it is 50°C or more and 75°C or less.

[0154] Furthermore, the conversion rate of the total monomer is preferably less than 99 mass% and is reacted with a modifier. The conversion rate is more preferably less than 98 mass%.

[0155] The conjugated diene-based polymer may be a random copolymer or a block copolymer. To make the conjugated diene-based polymer a rubber-like 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-based polymer.

[0156] Examples of random copolymers include, but are not limited to, a random copolymer composed of two or more conjugated diene compounds, such as a butadiene-isoprene random copolymer, a butadiene-styrene random copolymer, an isoprene-styrene random copolymer, and a random copolymer composed of the conjugated diene of the butadiene-isoprene-styrene random copolymer and an aromatic vinyl compound.

[0157] The composition distribution of each monomer in the copolymer chain is not particularly limited, and examples include a completely random copolymer, which approximates a statistically random composition, and a tapered (tilted) random copolymer, in which the composition is distributed in a tapered manner. The bonding mode of the conjugated diene, i.e., the composition of 1,4-bonds, 1,2-bonds, etc., can be uniform or distributed.

[0158] Examples of block copolymers include, but are not limited to, a type 2 block copolymer (diblock) consisting of 2 blocks, a type 3 block copolymer (triblock) consisting of 3 blocks, and a type 4 block copolymer (tetrablock) consisting of 4 blocks. The polymer forming a block can be a polymer consisting of one type of monomer or a copolymer consisting of two or more types of monomers. For example, if a polymer block of 1,3-butadiene is represented by "B", a copolymer of 1,3-butadiene and isoprene is represented by "B / I", a copolymer of 1,3-butadiene and styrene is represented by "B / S", and a polymer block of styrene is represented by "S", then 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 and SBSB-B4 type block copolymer, etc. are represented.

[0159] In the above equation, the boundaries of each block do not need to be clearly distinguished. If a polymer block is a copolymer composed of two types of monomers A and B, A and B can be distributed evenly or in a tapered shape within the block. <polymerisationsinitiator>

[0160] It is preferred to use at least one organic monolithium compound as a polymerization initiator.

[0161] Examples of organic monolithium compounds include, but are not limited to: low molecular weight compounds and solubilized oligomeric organic monolithium compounds.

[0162] Examples of organic monolithium compounds include a compound having a carbon-lithium bond, a compound having a nitrogen-lithium bond, and a compound having a tin-lithium bond in the bonding mode between the organic group and the lithium.

[0163] The use amount of the organic monolithium compound used as a polymerization initiator can be determined depending on the molecular weight of the desired conjugated diene-based polymer or modified conjugated diene-based polymer. The use amount of the monomer such as the conjugated diene compound to the use amount of the polymerization initiator is related to the degree of polymerization, that is, tends to be related to the number-average molecular weight and / or the weight-average molecular weight. Therefore, to increase the molecular weight, it is preferable to adjust the polymerization initiator toward a decrease, and to reduce the molecular weight, it is preferable to adjust the polymerization initiator toward an increase.

[0164] Examples of organic monolithium compounds include an alkyllithium compound with a substituted amino group or a dialkylaminolithium. In this case, a conjugated diene-based polymer is obtained, which has a nitrogen atom consisting of an amino group at the end of the polymerization initiation.

[0165] The substituted amino group is an amino group without an active hydrogen or with a structure in which the active hydrogen is protected. Examples of alkyllithium compounds with an amino group that does not have an active hydrogen include, but are not limited to, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium. Examples of alkyllithium compounds with an amino group in a structure in which the active hydrogen is protected include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

[0166] Examples of dialkylaminolithiums include, but are not limited to: lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium di-n-hexylamide, lithium diheptylamide, lithium diisopropylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium ethylpropylamide, lithium ethylbutyramide, lithium ethylbenzylamide, lithium methylphenethylamide, lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethyleneimide, lithium morpholide, 1-lithioazacyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, and 1-lithio-1,2,3,6-tetrahydropyridine.

[0167] These organic monolithium compounds having a substituted amino group can be used as the organic monolithium compound of the solubilized oligomer by reacting a small amount of a polymerizable monomer, e.g., a monomer such as 1,3-butadiene, isoprene, or styrene.

[0168] The organic monolithium compound is preferably an alkyllithium compound. In this case, a conjugated diene-based polymer with an alkyl group at the end of the polymerization initiation is obtained. Examples of alkyllithium compounds include, but are not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenelithium. As the alkyllithium compound, n-butyllithium and sec-butyllithium are preferred in view of their industrial availability and ease of control of the polymerization reaction.

[0169] These organic monolithium compounds can be used alone or in combination of two or more.

[0170] The organic monolithium compound can also be used in combination with other organometallic compounds. Examples of organometallic compounds include, but are not limited to, alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds. Examples of alkaline earth metal compounds include, but are not limited to, organic magnesium compounds, organic calcium compounds, and organic strontium compounds. Alkoxides, sulfonates, carbonates, and amide compounds of alkaline earth metals are also examples. Examples of organic magnesium compounds include dibutylmagnesium and ethylbutylmagnesium. Examples of other organometallic compounds include organoaluminum compounds.

[0171] Examples of polymerization reaction mode in the polymerization step include, but are not limited to, a batch type (also referred to as "batch type") and a continuous polymerization reaction type.

[0172] In the continuous process, one or two or more connected reactors can be used. For example, a tank-type reactor with a stirrer or a tubular reactor is used. In a continuous process, a monomer, an inactive solvent, and a polymerization initiator are preferably continuously fed into the reactor, a polymer solution containing the polymer is obtained in the reactor, and the polymer solution is discharged.

[0173] For example, a tank-type reactor equipped with a stirrer is used as a batch reactor. In a batch reactor, the monomer, the inactive solvent, and the polymerization initiator are preferably fed in. The monomer is added continuously or intermittently as needed during the polymerization. A polymer solution containing the polymer is obtained in the reactor, and the polymer solution is discharged after the polymerization is complete.

[0174] In order to obtain a conjugated diene-based polymer having a high active terminal content in the production of (A) modified conjugated diene-based polymer according to the present embodiment, the continuous type is preferred in which the polymer can be continuously discharged and subjected to the next reaction in a short time.

[0175] In the polymerization step, it is preferable to carry out the polymerization in an inactive solvent.

[0176] Examples of inactive solvents include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Examples of concrete

[0177] 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 hydrocarbons consisting of mixtures of these.

[0178] Before a polymerization reaction, by treating the allenes and acetylenes, which are impurities, with an organometallic compound, a conjugated diene-based polymer having a high concentration of active terminal groups tends to be obtained, and a modified conjugated diene-based polymer having a high modification rate can be obtained, which is preferable.

[0179] A polar compound can be added during the polymerization step. This allows an aromatic vinyl compound and a conjugated diene compound to be randomly copolymerized, and the polar compound can tend to be used as a vinylating agent to control the microstructure of the conjugated diene moiety. Furthermore, it also tends to be effective in promoting the polymerization reaction.

[0180] Examples of polar compounds include, but are not limited to: 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; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butyrate, sodium tert-butyrate, sodium amylate; and phosphine compounds such as triphenylphosphine.

[0181] These polar compounds can be used alone or in combination of two or more.

[0182] The use amount of a polar compound is not particularly limited and can be selected according to the objective, etc., but it is preferable that it be 0.01 mol or more and 100 mol or less with respect to 1 mol of polymerization initiators. Such a polar compound (vinylating agent) can be used in an appropriate amount according to a desired vinyl bond amount as a regulator of the microstructure of the conjugated diene portion of the polymer. Many polar compounds simultaneously exhibit an effective randomization effect in the copolymerization of conjugated diene compounds and aromatic vinyl compounds and can be used as a regulator for adjusting the distribution of aromatic vinyl compounds or the amount of styrene block.

[0183] As a method for randomizing the conjugated diene compound and the aromatic vinyl compound, a method in which a copolymerization reaction is initiated with the total amount of styrene and a part of 1,3-butadiene and the remaining 1,3-butadiene is intermittently added during the copolymerization reaction, as stated in JP 59-140221A, for example, can be used.

[0184] The conjugated diene-based polymer before the reaction step described later, which is obtained in the polymerization step, preferably has a Mooney viscosity measured at 110°C of 10 or more and 90 or less, more preferably 15 or more and 85 or less, and even more preferably 20 or more and 60 or less.

[0185] When the Mooney viscosity is in the above range, the modified conjugated diene-based polymer composition of the present embodiment tends to have excellent workability and wear resistance.

[0186] Although the amount of bonded conjugated diene in the conjugated diene-based polymer or modified conjugated diene-based polymer is not particularly limited, it is preferably 40 mass% or more and 100 mass% or less, and more preferably 55 mass% or more and 80 mass% or less.

[0187] Further, the amount of bonded aromatic vinyl in the conjugated diene-based polymer or modified conjugated diene-based polymer is not particularly limited, but is preferably 0 mass% or more and 60 mass% or less, and more preferably 20 mass% or more and 45 mass% or less.

[0188] When the amount of bonded conjugated diene and the amount of bonded aromatic vinyl are within the above ranges, the balance between low hysteresis loss and wet skid resistance, fracture toughness and wear resistance tends to be excellent when used as a vulcanizate.

[0189] Here, the amount of bonded aromatic vinyl can be measured by UV absorption of the phenyl group, and the amount of bonded conjugated diene can also be determined from this. Specifically, it can be measured according to the method described in the working examples described later.

[0190] In the conjugated diene-based polymer or modified conjugated diene-based polymer, the vinyl bond amount in the conjugated diene bond unit is not particularly limited, but it is preferably 10 mol% or more and 75 mol% or less, and more preferably 20 mol% or more and 65 mol% or less.

[0191] When the vinyl bonding amount is in the above range, the balance between low hysteresis loss and wet skid resistance, wear resistance and fracture toughness tend to be excellent when used as a vulcanizate.

[0192] Here, if the (A) modified conjugated diene-based polymer is a branched modified diene-based polymer and a copolymer of butadiene and styrene, the vinyl bond amount (1,2-bond amount) in the butadiene bond unit can be determined by the Hampton method (RR Hampton, Analytical Chemistry, 21,923 (1949)). Specifically, it can be measured by the method described in the working examples described later.

[0193] Regarding the microstructure of the modified conjugated diene-based polymer, a vulcanizate having an excellent balance between low hysteresis loss and wet skid resistance tends to be obtained when each bonding amount in the (A) modified conjugated diene-based polymer is in the above-described numerical range and the glass transition temperature of the (A) modified conjugated diene-based polymer is in the range of -50°C or more and less than -20°C.

[0194] Regarding the glass transition temperature, according to ISO 22768:2006, the DSC curve is recorded while raising the temperature within a predetermined temperature range, and the inflection point of the DSC difference curve is determined as the glass transition temperature. Specifically, it can be measured by the method described in the later working examples.

[0195] When the (A) modified conjugated diene-based polymer is a conjugated diene-aromatic vinyl copolymer, it is preferable that the number of blocks in which 30 or more aromatic vinyl units are linked is small or absent. Specifically, when the copolymer is a butadiene-styrene copolymer, the copolymer is decomposed by the Kolthoff method (method described in I.M. KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)), and in a known method for analyzing the amount of methanol-insoluble polystyrene, the block in which 30 or more aromatic vinyl units are linked is preferably 5.0 mass% or less, more preferably 3.0 mass% or less, based on the total amount of the copolymer. <modifizierungsreaktionsschritt>

[0196] According to the invention, the modified conjugated diene-based polymer is obtained by reacting a conjugated diene-based polymer with a nitrogen-containing compound. In the modification reaction step, the conjugated diene-based polymer obtained by the above-described method and a modifier having a bonding group that reacts with the active end of the conjugated diene-based polymer and a predetermined functional group that has an affinity or bonding reactivity for the filler are reacted.

[0197] In this case, a modifier having a predetermined functional group that also functions as a bonding group may be used. Furthermore, it is preferable to carry out the modification reaction step immediately after the polymerization step. In this case, a modified conjugated diene-based polymer with a high modification rate tends to be obtained.

[0198] When a linking group with monofunctional or bifunctional compound is used as a modifier, a linear-terminated modified diene-based polymer is obtained, and when a linking group with a polyfunctional compound having three or more functional groups is used, a branched modified diene-based polymer is obtained.

[0199] A monofunctional or polyfunctional compound containing nitrogen and optionally at least one of silicon, tin, phosphorus, oxygen, sulfur, and halogen is used as the modifier. Furthermore, an onium structure can be introduced into the modified conjugated diene-based polymer by adding and reacting an end 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 several of these elements, can also be used.

[0200] Preferred modifiers are those containing a functional group with little or no active hydrogen, such as a hydroxyl group, a carboxyl group, a primary amino group, and a secondary amino group. Active hydrogen can tend to deactivate the active end of the conjugated diene-based polymer. <Konkrete Beschreibung des Modifikators>

[0201] Examples of nitrogen-containing compounds include, but are not limited to: isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen-containing carbonyl compounds, nitrogen-containing vinyl compounds, and nitrogen-containing epoxy compounds.

[0202] Examples of silicon-containing compounds include an alkoxysilicon compound containing a nitrogen-containing group.

[0203] Examples of onium generators include a protected amine compound capable of forming a primary or secondary amine (ammonium generating), and an end modifier having functional groups in the molecule for bonding the onium generator and the modified conjugated diene-based polymer is preferably used.

[0204] Examples of functional groups for bonding the modified conjugated diene-based polymer include carbonyl groups (ketones, esters, etc.), unsaturated groups such as vinyl groups; epoxy groups, silicon halide groups, and alkoxysilicon groups.

[0205] The modifier has a nitrogen-containing functional group, and as the nitrogen-containing functional group, an amine compound having no active hydrogen is preferred, and examples thereof include a tertiary amine compound, protected amine compounds in which the above active hydrogen is replaced by a protecting group, and imine compounds represented by a general formula N-C.

[0206] Examples of isocyanate compounds of the nitrogen-containing compound that is a modifier include, but are not limited to: 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate (C-MDI), phenyl isocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, and 1,3,5-benzene triisocyanate.

[0207] Examples of isocyanuric acid derivatives 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-triazinane-2,4,6-trione, 1,3,5-tris(isocyanatomethyl)-1,3,5-triazinane-2,4,6-trione, and 1,3,5-trivinyl-1,3,5-triazinane-2,4,6-trione.

[0208] Examples of nitrogen-containing carbonyl compounds 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-dimethyl-picolinamide, and N,N-dimethyl-isonicotinamide.

[0209] Examples of nitrogen-containing vinyl compounds 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-morpholinophenyl)ethylene, and 1-phenyl-1-(4-N,N-dimethylaminophenyl)ethylene.

[0210] Examples of nitrogen group-containing epoxy compounds include, but are not limited to, an epoxy group-containing hydrocarbon compound bonded to an amino group, and may further have an epoxy group bonded to an ether group. For example, it is represented by the general formula (1).

[0211] In formula (1), R is a divalent or higher hydrocarbon group or a divalent or higher organic group having at least one polar group selected from oxygen such as ether, epoxy or ketone, sulfur such as thioether or thioketone, and nitrogen such as a tertiary amino group or an imino group.

[0212] The divalent or higher valent hydrocarbon group is a hydrocarbon group which may be saturated or unsaturated, linear, branched or cyclic and includes an alkylene group, an alkenylene group, a phenylene group, etc. Preferably, the carbon number is 1 to 20. Specific examples thereof include methylene, ethylene, butylene, cyclohexylene, 1,3-bis(methylene)cyclohexane, 1,3-bis(ethylene)cyclohexane, o-, m-, p-phenylene, m-, p-xylene, and bis(phenylene)methane.

[0213] In formula (1), R 1 and R 4 Hydrocarbon groups with 1 to 10 carbon atoms, where R 1 and R 4 can distinguish from each other. R 2 and R 5 are hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R 2 and R 5 may differ from each other.

[0214] R 3 is a hydrocarbon group having 1 to 10 carbon atoms or a structure of the following formula (2).

[0215] R 1 , R 2 and R 3 can be bonded to each other and have a cyclic structure.

[0216] If R 3 is a hydrocarbon group, it may further be a cyclic structure bonded to R. In this case, N and R bonded to R 3 are bound, be directly bound.

[0217] In formula (1), n ​​is an integer of 1 or more and m is an integer of 0 or 1 or more.

[0218] In formula (2), R 1 and R 2 in the same way as R 1 and R 2 defined in formula (1), and R 1 and R 2 may differ from each other.

[0219] As the nitrogen group-containing epoxy compound used as a modifier, preferred is one having an epoxy group-containing hydrocarbon group, and more preferred is one having a glycidyl group-containing hydrocarbon group.

[0220] Examples of epoxy group-containing hydrocarbon groups bonded to an amino group or an ether group include a glycidylamino group, a diglycidylamino group, and a glycidyloxy group. A more preferred molecular structure is an epoxy group-containing compound having a glycidylamino group or a diglycidylamino group and a glycidyloxy group, represented by the following general formula (3).

[0221] In formula (3), R is defined in the same way as R in formula (1) and R 6 is a hydrocarbon group having 1 to 10 carbon atoms or a structure of the following formula (4).

[0222] If R 6 is a hydrocarbon group, it can be bonded to R and assume a cyclic structure. In this case, N and R, which are bonded to R 6 are bound, be directly bound.

[0223] In formula (3), n is an integer of 1 or more and m is an integer of 0 or 1 or more.

[0224] The nitrogen group-containing epoxy compound used as a modifier is most preferably a compound having at least one diglycidylamino group and at least one glycidoxy group in the molecule.

[0225] Examples of nitrogen group-containing epoxy compounds used 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), 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, and N,N-diglycidylorthotoluidine, N,N-diglycidylaminomethylcyclohexane.

[0226] Among these, N,N-diglycidyl-4-glycidoxyaniline and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane are particularly preferred.

[0227] Examples of alkoxysilicon compound containing a nitrogen-containing group used as a modifier 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, und 2,2-Dimethoxy-8-(N,N-diethylamino)methyl-1,6-dxioxa-2-silacyclooctan.,

[0228] As a protected amine compound that can form a primary or secondary amine as a modifier, examples of compounds having an unsaturated bond and a protected amine in the molecule include, 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, and 1-[4-N,N-bis(trimethylsilyl)aminophenyl]-1-[4-N,N-dimethylaminophenyl]ethylene.

[0229] As a protected amine compound that can form a primary or secondary amine as a modifier, examples of a compound having alkoxysilane and protected amine in the molecule include, 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-trimethyl-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-diethoxy-1-butyl-1-aza-2-silacyclopentane, and 2,2-dimethoxy-1-methyl-1-aza-2-silacyclopentane.

[0230] Examples of sulfur-containing compounds used as a modifier include, but are not limited to: ethyl N,N-diethyldithiocarbamate, phenyl isothiocyanate, phenyl 1,4-diisothiocyanate, hexamethylene diisothiocyanate, and butyl isothiocyanate.

[0231] The modifier preferably has a silicon-containing functional group and the silicon-containing functional group preferably has an alkoxysilyl group or a silanol group.

[0232] The alkoxysilyl group possessed by the modifier, for example, tends to react with the active end of the conjugated diene-based polymer to dissociate alkoxylithium, thereby bonding the end of the conjugated diene-based polymer chain to the silicon of the modifier moiety. A value obtained by subtracting the number of SiOR reduced by the reaction from the total number of SiOR in one molecule of the modifier is the number of alkoxysilyl groups in the modifier moiety. Furthermore, the azasilyl group possessed by the modifier forms an >N-Li bond and a bond between the conjugated diene-based polymer end and silicon of the modifier moiety. There is a tendency for >N-Li bonds of water, etc., to easily become >NH and LiOH at the time of finishing. There is a tendency for unreacted alkoxysilyl groups remaining in the modifier to be removed by water or the like.can easily become silanols (Si-OH groups) at the time of finishing.

[0233] In the modification reaction step, when a compound having three alkoxy groups for one silicon atom is reacted, that is, when the active end of 3 mol of conjugated diene-based polymer is reacted with 1 mol of trialkoxysilane group, 1 mol of alkoxy group tends to remain unreacted even though the reaction occurs with up to 2 mol of the conjugated diene-based polymer. This is confirmed by the fact that 1 mol of the conjugated diene-based polymer remains as an unreacted polymer without reacting. In addition, by reacting many alkoxy groups, there is a tendency to suppress a sharp change in polymer viscosity resulting from causing a condensation reaction at the time of completion and storage. A modifier having one alkoxysilyl group per silicon atom is preferably used.

[0234] The reaction temperature in the modification reaction step is preferably the same as the polymerization temperature of the conjugated diene-based polymer, and particularly a temperature at which no heating is performed after polymerization. It is more preferably 0°C or more and 120°C or less, and even more preferably 50°C or more and 100°C or less.

[0235] As the reaction time in the modification reaction step, the reaction is preferably carried out in 10 seconds or more, more preferably in 30 seconds or more.

[0236] Any mixing method, such as mechanical mixing or mixing with a static mixer, can be used for mixing in the modification reaction step.

[0237] When the polymerization step is continuous, the reaction step is preferably continuous.

[0238] The reactor used in the modification reaction step can be a tank-type reactor equipped with a stirrer or a tube-type reactor. The modifier can be continuously fed into the reactor after being diluted with an inactive solvent. If the polymerization process is batch-type, the modification reaction step can be carried out by transferring the modifier to a polymerization reactor or by introducing the modifier into another reactor.

[0239] As a modifier, a nitrogen-containing compound of the following general formula (VI) is preferred.

[0240] In formula (VI), R 12 to R 14 each independently represents a single bond or an alkylene group having carbon atoms 1 to 20, R 15 to R 18 and R 20 each independently represents an alkyl group having carbon atoms 1 to 20, R 19 and R 22 each independently represents an alkylene group having carbon atoms 1 to 20 and R 21 an alkyl group or trialkylsilyl group having carbon atoms 1 to 20.

[0241] m represents an integer from 1 to 3 and p represents 1 or 2.

[0242] If several R 12 to R 22 are present, m and p are independent of each other.

[0243] i represents an integer from 0 to 6, j represents an integer from 0 to 6, k represents an integer from 0 to 6, and (i + j + k) represents an integer from 1 to 10.

[0244] A has a single bond, a hydrocarbon group having 1 to 20 carbon atoms or at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom, a silicon atom, a sulfur atom and a phosphorus atom and represents an organic group without active hydrogen.

[0245] The hydrocarbon group represented by A includes saturated, unsaturated, aliphatic, and aromatic hydrocarbon groups. The organic group without an active hydrogen is an organic group that inactivates the active end of the conjugated diene-based polymer. The organic group is an organic group without a functional group with an active hydrogen, such as a hydroxyl group (-OH), a secondary amino group (>NH), a primary amino group (-NH2), or a sulfhydryl group (-SH). When (i + j + k) is 1, A may also be omitted.

[0246] In formula (VI), A preferably represents one of the following general formulas (II) to (V).

[0247] In formula (II) B 1 a single bond or a hydrocarbon group having 1 to 20 carbon atoms and a is an integer from 1 to 10, where B 1 are independent of each other if several B 1 are present.

[0248] In formula (III), 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 is an integer from 1 to 10, where B 2 and B 3 are independent of each other if several B 2 and B 3 are present in each case.

[0249] In formula (IV), B 4 a single bond or a hydrocarbon group having 1 to 20 carbon atoms and a is an integer from 1 to 10, where B 4 are independent of each other if several B 4 are present.

[0250] In formula (V), B 5 a single bond or a hydrocarbon group having 1 to 20 carbon atoms and a is an integer from 1 to 10, where B 5 are independent of each other if several B 5 are present.

[0251] As a result, there is a tendency that a modified conjugated diene-based polymer having excellent performance can be obtained according to the present embodiment.

[0252] Examples of the modifier (including the modifiers described above) of the formula (VI) wherein (i + j + k) is 1 to 2 include, but are not limited to: 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), und (3-Trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentan)propyl]methylamin(trifunktionell).,

[0253] Examples of the modifier as a polyfunctional compound in which (i + j + k) is 3 or greater and A is represented by the formula (II) in the formula (VI) include the following, 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-propanediamine, Bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentan)propyl]-(3-trimethoxysilylpropyl)-1,3-propandiamin, 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-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-silacyclo)pentan)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-trimethylsilylsila-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-triethoxysilylpropyl)-[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-hexamethylendiamin, und Pentakis(3-trimethoxysilylpropyl)-diethylentriamin.,

[0254] Examples of the modifier in which A is represented by the formula (III) include, but are 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-propanediamine), and 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.

[0255] Examples of the modifier in which A is represented by the formula (IV) include, but are 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, and bis(3-trimethoxysilylpropyl)bis[3-(1-methoxy-2-methyl-1-sila-2-azacyclopentane)propyl]silane.,

[0256] Examples of the modifier in which A is represented by formula (V) include, but are not limited to, 3-tris[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-(2,2-dimethoxy-1-aza-2-silacyclopentane)propane, and 3-tris[2-(2,2-dimethoxy-1-aza-)2-silacyclopentane)ethoxy]silyl-1-trimethoxysilylpropane in formula (VI).

[0257] Examples of the modifier in the case where A represents an organic group having an oxygen atom and no active hydrogen include, in formula (VI): (3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl] ether (tetrafunctional), and 3,4,5-tris(3-trimethoxysilylpropyl)-cyclohexyl-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl] ether (octafunctional).

[0258] Examples of the modifier in the case where A represents an organic group having a phosphorus atom and no active hydrogen in the formula (VI) include, but are 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, and tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]phosphate.

[0259] In formula (VI), A preferably represents formula (II) or formula (III), and k represents 0. Therefore, it tends to be a readily available modifier, and when (A) the modified conjugated diene-based polymer is used as a vulcanizate, it tends to be excellent in wear resistance and low hysteresis loss performance.

[0260] Examples of such a modifier 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-bisaminotylcyclohexane, and Tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)methyl-1,3-propanediamine.

[0261] In the formula (VI), A more preferably represents the formula (II) or the formula (III), k represents 0, and in the formula (II) or the formula (III), a represents an integer of 2 to 10. As a result, the wear resistance and the low hysteresis loss performance during vulcanization tend to be excellent.

[0262] Examples of such modifiers 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.

[0263] The amount of the compound represented by formula (VI) as a modifier can be adjusted such that the number of moles of the conjugated diene-based polymer reacts with the number of moles of the modifier in a desired stoichiometric ratio. This achieves a desired degree of branching.

[0264] The specific number of moles of the conjugated diene-based polymer, i.e., the number of moles of the polymerization initiator, is preferably 1.0 times or more, more preferably 2.0 times or more, relative to the number of moles of the modifier. In this case, in formula (VI), the number of functional groups ((m-1) × i + p × j + k) of the modifier is preferably an integer from 1 to 10, and more preferably an integer from 2 to 10. <hydrierungsschritt>

[0265] The (A) modified conjugated diene-based polymer can be obtained by hydrogenating the conjugated diene moiety. The method for hydrogenating the conjugated diene moiety is not particularly limited, and a known method can be used.

[0266] As a suitable hydrogenation process, a hydrogenation process by blowing gaseous hydrogen into a polymer solution in the presence of a catalyst can be used.

[0267] Examples of catalysts include a heterogeneous catalyst such as a catalyst in which a noble metal is supported on a porous inorganic substance; homogeneous catalysts such as a catalyst in which a salt such as nickel salt or cobalt salt is solubilized and reacted with organic aluminum or the like; or a catalyst using a metallocene such as titanocene. Among these, titanocene catalysts are preferred in view of the selection of mild hydrogenation conditions. The hydrogenation of the aromatic group can be carried out using a noble metal-supported catalyst.

[0268] Specific examples of hydrogenation catalysts include, but are not limited to: (1) a supported heterogeneous hydrogenation catalyst in which a metal such as Ni, Pt, Pd or Ru is supported on carbon, silica, alumina, diatomaceous earth or the like, (2) a so-called Ziegler hydrogenation catalyst using a transition metal salt such as an organic acid salt or acetylacetone salt of Ni, Co, Fe, Cr or the like and a reducing agent such as organic aluminum, (3) so-called organometallic complexes such as organometallic compounds such as Ti, Ru, Rh and Zr. Examples of hydrogenation catalysts further include known hydrogenation catalysts disclosed in Japanese Patent Publications JP 42-8704, JP 43-6636, JP 63-4841, JP 1-37970, JP 1-53851, JP 2-9041, JP 8-109219.Examples of preferred hydrogenation catalysts include a reaction mixture of a titanocene compound and a reducing organometallic compound. <Zusatz von Deaktivator, Neutralisator usw.>

[0269] In the production process of (A) modified conjugated diene-based polymer, a deactivator, a neutralizer, etc. may be added to a solution of the modified conjugated diene-based polymer as needed after the reaction step.

[0270] Examples of deactivators include, but are not limited to, water, alcohols such as methanol, ethanol, and isopropanol. Examples of neutralizers include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a mixture of carboxylic acids with 9 to 11 carbon atoms, primarily 10, and with many branches), an aqueous solution of an inorganic acid, and carbon dioxide gas. <Zusatz von Kautschukstabilisator und Strecköl>

[0271] From the viewpoint of preventing gel formation after polymerization and improving processing stability, it is preferable to add a rubber stabilizer to the (A) modified conjugated diene-based polymer. Known rubber stabilizers can be used as the rubber stabilizer, and examples include, but are not limited to, antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl 3-(4'-hydroxy-3',5'-ditert-butylphenol)propinate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol.

[0272] In order to further improve the processability of the (A) modified conjugated diene-based polymer, an extender oil may be added to the (A) modified conjugated diene-based copolymer as needed.

[0273] The method for adding the extender oil to the modified conjugated diene-based polymer is not limited to the following, but a method in which the extender oil is added to the polymer solution and mixed to desolventize the oil-extended copolymer solution is preferred. Examples of extender oils include flavor oil, naphthene oil, and paraffin oil. Among them, from the viewpoints of environmental safety, oil bleeding prevention, and wet skid resistance, a substitute aromatic oil having a polycyclic aromatic (PCA) component of 3 mass% or less by the IP346 method is preferred. Examples of alternative flavor oils include TDAE (Treated Distillate Aromatic Extracts) and MES (Mild Extraction Solvate) shown in Kautschuk Gummi Kunststoffe 52 (12)799 (1999), as well as RAE (Residual Aromatic Extracts).The addition amount of the extender oil is not particularly limited, but is preferably 10 parts by mass or more and 60 parts by mass or less, and more preferably 20 parts by mass or more and 37.5 parts by mass or less, based on 100 parts by mass of the (A) modified conjugated diene-based polymer.

[0274] As a method for obtaining the (A) modified conjugated diene-based polymer from the polymer solution, a known method can be used. Examples of methods include a method in which, after separating the solvent by steam stripping or the like, the polymer is filtered out and further dehydrated and dried to obtain the polymer, a method in which the solvent is concentrated in a rinsing tank and deaerated with an extruder, etc., and a method of directly deaerating with a drum dryer or the like. ((B) Natural rubber and / or polyisoprene rubber)

[0275] The rubber composition of the present embodiment contains (B) natural rubber and / or polyisoprene rubber (hereinafter referred to simply as (B) component if necessary).

[0276] The (B) component is at least one rubber selected from the group consisting of natural rubber and polyisoprene rubber.

[0277] With respect to the polyisoprene rubber as (B) component, the weight-average molecular weight is preferably 4 × 10 5 or more.

[0278] This weight-average molecular weight is a value converted to polystyrene, measured by a gel permeation chromatography (GPC) method.

[0279] Furthermore, the amount of the 1,4-cis bond (sometimes referred to as the cis-1,4 bond amount) of (B) polyisoprene rubber is 90% or more, more preferably 95% or more, and particularly preferably 98% or more. When the 1,4-cis bond amount of the polyisoprene rubber is 90% or more, the elongational crystallinity can be expressed, and when it is 95% or more, sufficient elongational crystallinity can be expressed.

[0280] When the 1,4-cis bond amount of the (B) polyisoprene rubber is within the above-mentioned more preferable range or particularly preferable range, it is advantageous in view of improving durability due to extensional crystallinity.

[0281] When the (B) polyisoprene rubber is an isoprene copolymer, the term "1,4-cis bond amount of the polyisoprene rubber" means "1,4-cis bond amount of the isoprene-derived part of the polyisoprene rubber".

[0282] The 1,4-trans bond amount (sometimes referred to as trans-1,4 bond amount) of (B) polyisoprene rubber is not particularly limited and can be appropriately selected depending on the purpose, and is preferably 10% or less, and more preferably 5% or less.

[0283] When the 1,4-trans bond amount of (B) polyisoprene rubber is 10% or less, more preferably 5% or less, sufficient extensional crystallinity can be expressed. When the amount of 1,4-trans bonds in the polyisoprene rubber is within the above preferred range, it is advantageous from the viewpoint of improving durability due to extensional crystallinity.

[0284] When the (B) polyisoprene rubber is an isoprene copolymer, the term "1,4-trans bonding amount of the polyisoprene rubber" means "1,4-trans bonding amount of the isoprene-derived part of the polyisoprene".

[0285] The amount of 3,4-vinyl bonds in the (B) polyisoprene rubber is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5% or less, and more preferably 2% or less.

[0286] When the amount of 3,4-vinyl bonds of (B) polyisoprene rubber is 5% or less, sufficient strain crystallinity can be expressed.

[0287] When the amount of 3,4-vinyl bonds of the (B) polyisoprene rubber is within the above preferred range, it is advantageous from the viewpoint of improving durability due to elongational crystallinity.

[0288] When the (B) polyisoprene rubber is an isoprene copolymer, the term "the amount of 3,4-vinyl bonds in the polyisoprene rubber" means "the amount of 3,4-vinyl bonds of the isoprene-derived portion of the polyisoprene rubber."

[0289] When the 1,4-cis bond amount of (B) polyisoprene is 90% or more as described above, it is possible to develop strain crystallinity and improve durability. However, workability tends to be inferior. Therefore, in (A) modified conjugated diene-based polymer, the modification rate of the low molecular weight component is relatively high, so that the mixer torque is well applied when kneading with the filler, etc., and a rubber composition with good filler dispersibility tends to be obtained in a short time. Therefore, by combining (A) modified conjugated diene-based polymer and (B) polyisoprene, there is a tendency for torque to be well applied and kneaded well, so workability improves.

[0290] The natural rubber as component (B) has a microgel content of 5 to 24 mass%, and examples include smoked sheets (smoked sheets), which are ribbon-shaped rubber. Smoked sheets are not particularly limited, and examples include RSS 1X-5, white crepe 1X, and pale crepe 1X-3.

[0291] (B) If natural rubber contains foreign matter, there is a risk of destruction by the foreign matter. Therefore, it is preferable that the foreign matter content is minimal and the color is light, and RSS1X, white crepe 1X, and pale crepe 1X are preferable.

[0292] Examples of natural rubber (B) include block rubber. Examples of block rubber include, but are not limited to: SMR (block rubber from Malaysia), SIR (block rubber from Indonesia), TTR (block rubber from Thailand), SCR (block rubber from China), and SSR (block rubber from Singapore).

[0293] In SMR, it is preferable to have fewer impurities and ash, with L, CV50, and CV60 being preferred. It is known that the main component of natural rubber is polyisoprene, mostly with 1,4-cis bonds, and contains ultra-high molecular weight components with a branched structure due to proteins and lipids contained as impurities. Therefore, crystallization can proceed easily, mechanical properties are improved, and wear resistance and fracture toughness are improved.

[0294] As (B) natural rubber, the long chain branching index (LCB index) at 70°C is preferably 10.6 or more and 17.9 or less, and the long chain branching index (LCB index) at 130°C is 3.0 or less. More preferably, the long chain branching index (LCB index) at 70°C is 10.6 or more and 15.0 or less, and the long chain branching index (LCB index) at 130°C is 2.0 or less and 3.0 or less.

[0295] The long chain branching index (LCB index) at 70°C is even more preferably 12.0 or more and 14.5 or less. When the long chain branching index (LCB index) at 70°C is 10.6 or more and 17.9 or less, and the long chain branching index (LCB index) at 130°C is 3.0 or less, it is possible to sufficiently ensure the crack resistance of natural rubber and achieve both the wear resistance and low hysteresis loss of natural rubber at a high level.

[0296] As (B) natural rubber, the microgel content is 5 to 24 mass%, more preferably 7 to 22 mass%, and even more preferably 10 to 20 mass%.

[0297] When the content of microgel in (B) natural rubber is 5 mass% or more, the

[0298] Wear resistance and fracture toughness tend to be improved, and when it is 24 mass% or less, machinability tends to be improved.

[0299] Since (B) natural rubber has inferior heat resistance, it tends to lack the high wear resistance and fracture toughness that are the characteristics of natural rubber when kneaded for a long time. Therefore, by combining (A) with the modified conjugated diene-based polymer with good torque and good filler dispersibility in a short time with the natural rubber, it is possible to obtain a rubber composition with a short kneading time and good filler dispersibility, where the high wear resistance and fracture toughness that are the characteristics of natural rubber tend to be expressed. (Rubber composition)

[0300] The rubber composition of the present embodiment contains (A) 100 parts by mass of the modified conjugated diene-based polymer, (B) 10 to 250 parts by mass of natural rubber and / or polyisoprene rubber, and (C) a silica-containing filler.

[0301] The (C) silica-containing filler contains silica and may contain inorganic silica fillers other than silica (SiO2), such as carbon black, metal oxide and metal hydroxide, as constituent components.

[0302] Among these, inorganic fillers based on silicon dioxide are preferred.

[0303] These can be used alone or in combination of two or more.

[0304] Further, the rubber composition of the present embodiment tends to exhibit excellent workability and an excellent balance between low hysteresis loss and wet skid resistance, as well as fracture strength and wear resistance, by dispersing the inorganic silica-based filler when used as a vulcanizate.

[0305] Even when the rubber composition of the present embodiment is used for vulcanized rubber applications such as automobile parts such as tires and vibration-proof rubber, shoes, etc., it is preferable to contain a silica-based inorganic filler.

[0306] The content of the filler containing (C) silica in the rubber composition of the present embodiment is 5.0 parts by mass or more and 150 parts by mass or less based on 100 parts by mass of the (A) modified conjugated diene-based polymer, and preferably 20 parts by mass or more and 100 parts by mass or less.

[0307] The content of the filler containing (C) silica is 5.0 parts by mass or more in view of developing the effect of adding the (C) component, and 150 parts by mass or less in view of sufficient dispersion of the (C) component and practically sufficient workability of the rubber composition and mechanical strength.

[0308] The silica-based inorganic filler is not particularly limited, and known fillers can be used, but solid particles containing SiO2 and Si3Al as component units are preferable, and solid particles containing SiO2 and Si3Al as the main component of the component unit are more preferable. Here, the main component means a component contained in the silica-based inorganic filler in an amount of 50% by mass or more, preferably 70% by mass or more, even more preferably 80% by mass or more.

[0309] Furthermore, it becomes a silicon dioxide when SiO2 is 100 mass%, where silicon dioxide is a form of silicon dioxide-based inorganic filler.

[0310] Examples of specific silica-based inorganic fillers include, but are not limited to, inorganic substances such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fibers. They also include silica-based inorganic fillers that impart hydrophobicity to the surface and mixtures of silica-based inorganic fillers and non-silica-based inorganic fillers.

[0311] Among them, silica and glass fibers are preferred in terms of strength and wear resistance, and silica is more preferred.

[0312] Examples of silica include dry silica, wet silica, and synthetic silica. Among these silicas, wet silica is preferred from the viewpoint of an excellent balance between the effect of improving fracture toughness and wet skid resistance.

[0313] In the rubber composition of the present embodiment, the nitrogen adsorption specific surface area determined by the BET adsorption method of the inorganic silica-based filler as (C) component is 100 m 2 / g or more and 300 m 2 / g or less and more preferably 170 m 2 / g or more and 250 m 2 / g or less from the viewpoint of obtaining practically good wear resistance and good fracture strength.

[0314] If required, an inorganic silica-based filler with a relatively small specific surface area (e.g. a specific surface area of ​​200 m 2 / g or less) and an inorganic silica-based filler with a relatively large specific surface area (e.g. 200 m 2 / g or more) may be used in combination.

[0315] In the present embodiment, the rubber composition improves the dispersibility of the (C) component when a silica-based inorganic filler having a relatively large specific surface area (e.g., 200 m 2 / g or more) is used, and is particularly effective in improving wear resistance, so that a high balance between good fracture toughness and low hysteresis loss tends to be achieved.

[0316] The content of the silica-based inorganic filler as the (C) component in the rubber composition of the present embodiment is 5.0 parts by mass or more and 150 parts by mass or less based on 100 parts by mass of the (A) modified conjugated diene-based polymer, and more preferably 20 parts by mass or more and 100 parts by mass or less. The content of the silica-based inorganic filler as the (C) component is 5.0 parts by mass or more from the viewpoint of the effect of adding the silica-based inorganic filler, and 150 parts by mass or less from the viewpoint of sufficiently dispersing the inorganic filler and making the workability and mechanical strength of the composition practically sufficient.

[0317] Examples of carbon black include, but are not limited to, carbon black of any class such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon black with a specific nitrogen adsorption surface area of ​​50 m 2 / g or more and a dibutyl phthalate (DBP) oil absorption of 80 mL / 100 g or less is preferred.

[0318] The content of carbon black is preferably 0.5 parts by mass or more and 100 parts by mass or less, and more preferably 3.0 parts by mass or more and 100 parts by mass or less, and more preferably 5.0 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of the rubber component containing the (A) modified conjugated diene-based polymer.

[0319] The content of carbon black is preferably 0.5 parts by mass or more from the viewpoint of exhibiting the performance such as dry grip performance and conductivity required for tire applications, and from the viewpoint of dispersibility, it is preferably 100 parts by mass or less.

[0320] Metal oxide refers to solid particles having the chemical formula MxOy (M represents a metal atom, and x and y each independently represent an integer from 1 to 6) as the main component of the component unit. Metal oxide includes, but is not limited to, aluminum oxide, titanium oxide, magnesium oxide, and zinc oxide.

[0321] Examples of metal hydroxides include, but are not limited to: aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide. (Rubber-like polymer)

[0322] The modified conjugated diene-based polymer composition and the rubber composition of the present embodiment may also contain a rubbery polymer (hereinafter simply referred to as "other rubbery polymer") apart from the (A) component, the (B) component, and the (C) component.

[0323] Examples of such other rubbery polymers include, but are not limited to: conjugated diene-based polymer or hydrogenated products thereof, random copolymers of a conjugated diene compound and a vinyl aromatic compound or hydrogenated products thereof, a block copolymer of a conjugated diene compound and a vinyl aromatic compound or hydrogenated products thereof, and a non-diene-based polymer.

[0324] Specific examples of other rubbery polymers include, but are not limited to: styrene elastomers such as butadiene rubber or hydrogenated products thereof, styrene-butadiene rubber or hydrogenated products thereof, styrene-butadiene block copolymer or hydrogenated products thereof, styrene-isoprene block copolymers or hydrogenated products thereof, and acrylonitrile-butadiene rubbers or hydrogenated products thereof.

[0325] Examples of non-diene polymers include, but are not limited to, olefin elastomer such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber, butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylate ester conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber.

[0326] The various rubber-like polymers mentioned above can be modified rubbers containing polar functional groups such as hydroxyl groups and amino groups. Butadiene rubber, styrene-butadiene rubber, and butyl rubber are preferred for use in tires.

[0327] The weight-average molecular weight of the other rubber-like polymer is preferably 2,000 or more and 2,000,000 or less, and more preferably 5,000 or more and 1,500,000 or less, from the perspective of the balance between performance and processing properties. A low-molecular-weight rubber-like polymer, so-called liquid rubber, can also be used.

[0328] These other rubbery polymers may be used alone or in combination of two or more.

[0329] When the above-mentioned other rubbery polymer is mixed and added to the above-mentioned modified conjugated diene-based polymer composition or the rubbery polymer composition of the present embodiment, the content ratio (mass ratio) of the modified conjugated diene-based polymer composition to the other rubbery polymer as (modified conjugated diene-based polymer composition / other rubbery polymer) is preferably 10 / 90 or more and 100 / 0 or less, more preferably 20 / 80 or more and 90 / 10 or less, and even more preferably 50 / 50 or more and 80 / 20 or less.

[0330] Accordingly, the rubber component obtained by combining the modified conjugated diene-based polymer composition and the other rubbery polymer preferably contains 10 parts by mass or more and 100 parts by mass or less, more preferably 20 parts by mass or more and 90 parts by mass or less, and even more preferably 50 parts by mass or more and 80 parts by mass or less of the modified conjugated diene-based polymer composition with respect to the total amount (100 parts by mass) of the rubber component.

[0331] When the content ratio (modified conjugated diene-based polymer composition / other rubbery polymer) is in the above range, when used as a vulcanizate, the balance between low hysteresis loss and wet skid resistance is excellent, and the wear resistance and fracture strength are also satisfied. (silane coupling agent)

[0332] The rubber composition of the present embodiment may contain a silane coupling agent.

[0333] As the silane coupling agent, a compound is preferred that has the function of closing the interaction between the rubber component and the filler containing (C) silica, has an affinity or bonding group for each of the rubber component and the filler containing (C) silica, particularly a silica-based inorganic filler, and preferably has a sulfur bonding moiety and an alkoxysilyl group or a silanol group moiety in one molecule. Examples of such compounds include, but are not limited to, bis[3-(triethoxysilyl)propyl]tetrasulfide, bis[3-(triethoxysilyl)propyl]disulfide, and bis[2-(triethoxysilyl)ethyl]tetrasulfide.

[0334] The content of the silane coupling agent is preferably 0.1 part by mass or more and 30 parts by mass or less, more preferably 0.5 part by mass or more and 20 parts by mass or less, and even more preferably 1.0 part by mass or more and 15 parts by mass or less, based on 100 parts by mass of the above-described (C) silica-containing filler. When the content of the silane coupling agent is within the above range, the additive effect of the silane coupling agent tends to be more remarkable. (rubber plasticizer)

[0335] The rubber composition of the present embodiment may contain a rubber softener in view of improving workability.

[0336] Mineral oil or a liquid or low-molecular synthetic plasticizer is suitable as a rubber plasticizer.

[0337] Mineral oil-based rubber softeners, so-called process oils or extender oils, used to soften, increase the volume, and improve the workability of rubber, are mixtures of aromatic, naphthenic, and paraffin chains. A paraffin chain with 50% or more carbon atoms in the total carbon is called paraffin type, and naphthenic carbon atoms with 30% or more and 45% or less in the total carbon are called naphthenic, and aromatic carbon atoms of more than 30% of the total carbon are called aromatic.

[0338] When (A) the modified conjugated diene-based polymer is a copolymer of a conjugated diene compound and an aromatic vinyl compound, as the rubber softener to be used, one having a suitable aromatic content is preferable because it is familiar with the copolymer of the conjugated diene compound and the aromatic vinyl compound.

[0339] The content of the rubber softener is preferably 0 part by mass or more and 100 parts by mass or less, more preferably 10 parts by mass or more and 90 parts by mass or less, and even more preferably 30 parts by mass or more and 90 parts by mass or less, based on 100 parts by mass of the rubber component containing the (A) and (B) components.

[0340] By making the content of the plasticizer for rubber 100 parts by mass or less with respect to 100 parts by mass of the rubber component, bleeding tends to be suppressed and stickiness on the surface of the rubber composition is suppressed. (Vulcanized composition)

[0341] The rubber composition of the present embodiment may be a vulcanized composition vulcanized with a vulcanizing agent.

[0342] Examples of vulcanizing agents include, but are not limited to, free radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and polymeric polysulfide compounds.

[0343] The content of the vulcanizing agent is preferably 0.01 part by mass or more and 20 parts by mass or less, and more preferably 0.1 part by mass or more and 15 parts by mass or less, based on 100 parts by mass of the rubber component including the (A) component and the (B) component. Conventionally known methods can be used as the vulcanization method, and the vulcanization temperature is preferably 120°C or more and 200°C or less, and more preferably 140°C or more and 180°C or less.

[0344] During vulcanization, a vulcanization accelerator can be used if required.

[0345] As the vulcanization accelerator, conventionally known materials can be used, and examples thereof include, but are not limited to: vulcanization accelerators of sulfenamide, guanidine, thiuram, aldehyde amine, aldehyde ammonia, thiazole, thiourea, and dithiocarbamate.

[0346] Examples of vulcanization aids include, but are not limited to: zinc white and stearic acid.

[0347] The content of the vulcanization accelerator is preferably 0.01 part by mass or more and 20 parts by mass or less, and more preferably 0.1 part by mass or more and 15 parts by mass or less, based on 100 parts by mass of the rubber component including the (A) component and the (B) component.

[0348] For the rubber composition of the present embodiment, various additives other than those described above such as plasticizers, fillers, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, lubricants, etc. may be used within a range not impairing the purpose of the present embodiment.

[0349] Other known plasticizers can be used.

[0350] Examples of other fillers include calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate.

[0351] Known materials can be used as the above heat stabilizer, antistatic agent, weather stabilizer, anti-aging agent, colorant and lubricant. [Process for producing a rubber composition]

[0352] The method for producing the rubber composition of the present embodiment comprises kneading (A) 100 parts by mass of modified conjugated diene-based polymer, (B) 10 to 80 parts by mass of the natural rubber and / or polyisoprene rubber, and (C) 5 to 150 parts by mass of the filler containing silica.

[0353] (C) The filler contains silicon dioxide as an essential component, and an optional component may also be contained together with silicon dioxide as an essential component.

[0354] As the silica constituting the (C) filler, silica commonly used as a filler can be used. From the viewpoint of rolling resistance and impact resilience of a rubber elastic body obtained from a rubber composition, synthetic silica with a primary particle diameter of 50 nm or less is preferred.

[0355] The content ratio of silica constituting the (C) filler is 10 to 120 parts by mass, and more preferably 20 to 100 parts by mass, based on 100 parts by mass of the rubber component containing the (A) modified conjugated diene-based polymer and (B) natural rubber and / or polyisoprene rubber.

[0356] When the content ratio of silica constituting the (C) filler is within the above range, a good balance between hardness and rolling resistance tends to be obtained in an elastic rubber body obtained from the rubber composition.

[0357] In (C) filler, in addition to silicon dioxide, which is an essential component, an optional component may also be included.

[0358] As an optional component, inorganic silica-based fillers other than silicon dioxide (SiO2), carbon black, metal oxide and metal hydroxide may be included as constituent components, and specific examples thereof include inorganic oxides such as aluminum oxide, titanium oxide, calcium oxide and magnesium oxide, inorganic hydroxides such as aluminum hydroxide and magnesium hydroxide and carbonates such as magnesium carbonate.

[0359] These can be used alone or in combination of two or more.

[0360] The rubber composition of the present embodiment can be prepared, for example, by using a plastic mill and mixing and kneading optional components together with the (A), (B) and (C) components.

[0361] The (A) and (B) components act in such a way that the (A) component increases the dispersibility of silicon dioxide, while the (B) component decreases the dispersibility of silicon dioxide.

[0362] Therefore, by adjusting the blending proportion of the (A) and (B) components, the dispersibility of silica can be controlled, and the balance between the rolling resistance and the impact resilience in the elastic rubber body obtained from the rubber composition of the present embodiment can be improved, so that the dispersibility of silica can be improved.

[0363] Consequently, according to the rubber composition of the present embodiment, it is possible to obtain an elastic rubber body having a low rolling resistance and excellent impact resilience.

[0364] In the method for producing the rubber composition of the present embodiment, it is preferable to knead (A) 100 parts by mass of the modified conjugated diene-based polymer and the (C) filler containing silica, and after obtaining a kneaded product, knead the kneaded product and (B) natural rubber and / or polyisoprene rubber.

[0365] Specifically, it is preferable to first knead the (A) modified conjugated diene-based polymer and the (C) filler containing the silicon dioxide and optional components, and after obtaining a kneaded product, add the (B) natural rubber and / or polyisoprene rubber to the kneaded product and further knead.

[0366] By kneading the (A) modified conjugated diene-based polymer and the (C) filler containing the silica, and after obtaining a kneaded product, kneading the kneaded product and the (B) natural rubber and / or polyisoprene rubber, the dispersibility of the silica in the rubber composition can be further improved, so that the obtained elastic rubber body has a further lower rolling resistance and excellent impact resilience.

[0367] The method for producing the rubber composition of the present embodiment is not limited to the method in which the (A) modified conjugated diene-based polymer and the (C) filler containing silica are kneaded, and after obtaining a kneaded product, the kneaded product and the (B) natural rubber and / or polyisoprene rubber are kneaded, and may be, for example, a method in which the (A) modified conjugated diene-based polymer, the (B) natural rubber and / or polyisoprene rubber, the (C) filler containing silica, and optional components are kneaded simultaneously.

[0368] Examples of methods for mixing the constituent components in producing the rubber composition of the present embodiment include, but are not limited to, a melt-kneading method using a typical mixer such as an open roll, Banbury mixer, kneader, single-screw extruder, twin-screw extruder, multi-screw extruder, etc., and a method in which the solvent is removed by heating after dissolving and mixing the components.

[0369] Among them, the melt kneading process by roller, Banbury mixer, kneader and extruder is preferred in view of productivity and good kneading properties.

[0370] Further, a method of simultaneously kneading the constituent components of the rubber composition of the present embodiment and a method of mixing several times can be respectively employed.

[0371] In the process for producing the rubber composition of the present embodiment, vulcanization may be carried out with a vulcanizing agent to obtain a vulcanized composition.

[0372] Examples of vulcanizing agents include, but are not limited to: free radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur and sulfur compounds.

[0373] Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, polymeric polysulfide compounds, etc.

[0374] The content of the vulcanizing agent is preferably 0.01 part by mass or more and 20 parts by mass or less, more preferably 0.1 part by mass or more and 15 parts by mass or less, based on 100 parts by mass containing the (A) and (B) components.

[0375] As the vulcanization method, a conventionally known method can be used, and the vulcanization temperature is preferably 120°C or more and 200°C or less, more preferably 140°C or more and 180°C or less.

[0376] During vulcanization, a vulcanization accelerator may be used as needed. A conventionally known material may be used as the vulcanization accelerator, and examples include, but are not limited to, vulcanization accelerators such as sulfenamide, guanidine, thiuram, aldehyde amine, aldehyde ammonia, thiazole, thiourea, and dithiocarbamate.

[0377] Examples of vulcanization aids include, but are not limited to: spangle and stearic acid.

[0378] The content of the vulcanization accelerator is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or more, based on a total of 100 parts by mass containing the (A) and (B) components.

[0379] In the process for producing the rubber composition of the present embodiment, an additive step may also be carried out in which various additives such as other plasticizers, fillers, heat stabilizers, antistatic agents, weathering stabilizers, antiaging agents, colorants, and lubricants are used within the range not impairing the purpose of the present embodiment.

[0380] Other known plasticizers can be used.

[0381] Examples of other fillers include calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate.

[0382] Known materials can be used as the above heat stabilizer, antistatic agent, weatherproof stabilizer, anti-aging agent, colorant and lubricant. [Tires]

[0383] The rubber composition containing the modified conjugated diene-based polymer composition of the present embodiment is suitably used as a rubber composition for tires.

[0384] The use of the rubber composition for tires is not limited to the following, and can be used, for example, for various tires such as fuel-efficient tires, all-season tires, high-performance tires, and studless tires; tire parts such as treads, carcasses, sidewalls, and bead portions. In particular, the rubber composition for tires containing a modified conjugated diene-based polymer composition of the present embodiment excels in the balance between low hysteresis loss and wet skid resistance, as well as in wear resistance, when used as a vulcanizate, so that it is more suitable for use as a fuel-efficient tire and a tread for a high-performance tire. [Examples of implementation]

[0385] Although concrete embodiments and comparative examples are given below and the present embodiment is described in detail, this embodiment is not limited to the following embodiments and comparative examples.

[0386] Various physical properties were measured using the following methods. <Reinigung von 1,3-Butadien>

[0387] 1,3-Butadiene used for polymerization of the modified conjugated diene-based polymer was purified by the following steps. (washing process)

[0388] The operation was carried out under conditions of a circulating water volume of 1 m 3 / hr and a renewal water volume (make-up volume) of 0.1 m 3 / hr carried out.

[0389] 1,3-Butadiene and wash water were mixed using a static mixer (Static Mixer N60 series, manufactured by Noritake Co., Ltd.), then transferred to a decanter and 1,3-butadiene phase and the aqueous phase were separated.

[0390] The operation was carried out under conditions of a liquid temperature of 30°C and a decanter pressure of 1.0 MPaG.

[0391] The residence time of the 1,3-butadiene phase in the decanter was 30 minutes.

[0392] The aqueous phase separated by the decanter was placed in a 1,3-butadiene removing tank, mixed with steam and heated to 89°C, and at the same time, 1,3-butadiene was removed from the aqueous phase, with total pressure set to 0.01 MPaG. (Method for removing oxygen with a deoxidizer)

[0393] Subsequently, a 10% aqueous solution of Daiclean F-504 (manufactured by Kurita Water Industries Ltd.) was used as a deoxidizer, and the 1,3-butadiene and the aqueous solution of the deoxidizer were circulated after the above procedure (water washing step) at a circulation flow rate of 1 m 3 / hr using a static mixer, and a liquid-liquid extraction was performed. Then, they were transferred to the decanter, and the 1,3-butadiene phase and the aqueous phase were separated by the decanter.

[0394] The residence time of the 1,3-butadiene phase in the decanter was 30 minutes. The operation was carried out under conditions of a liquid temperature of 30°C and a decanter pressure of 1.0 MPaG. (Method for removing the polymerization inhibitor)

[0395] Subsequently, a 10% aqueous sodium hydroxide solution was mixed with 1,3-butadiene according to the above (oxygen removal step using a deoxidizer) at a circulation flow rate of 1 m 3 / hr using a packed column containing a pole ring. A liquid-liquid extraction was performed, and the mixture was further transferred to another decanter, and the 1,3-butadiene phase and the aqueous phase were separated by the other decanter.

[0396] The residence time of the 1,3-butadiene phase in the other decanter was 60 minutes. During the polymerization inhibitor removal step, the process was carried out under conditions of a liquid temperature of 30°C and a decanter pressure of 1.0 MPa. (dewatering column step)

[0397] Mixed hexane was added to the 1,3-butadiene phase separated by the other decanter to feed it to the dewatering column with a 1,3-butadiene concentration of 50 mass%.

[0398] In the dehydration column, the distilled azeotropic mixture of 1,3-butadiene and water was cooled from the top (column head), condensed and then transferred to a decanter, and in the decanter the 1,3-butadiene phase and the aqueous phase were separated.

[0399] The aqueous phase was removed and the 1,3-butadiene phase was recycled to the column inlet of the dewatering column and the dewatering column step was carried out continuously.

[0400] A mixed liquid of dehydrated 1,3-butadiene and hexane was taken from the bottom of the dehydration column (column bottom). (adsorption step)

[0401] The mixture of 1,3-butadiene and hexane was passed through a 500-liter desiccant dryer containing activated alumina (a vertical cylindrical tank manufactured by Hitachi, Ltd.) to adsorb and remove a small amount of residual impurities in 1,3-butadiene, and a purified 1,3-butadiene was obtained. <Reinigung von Styrol>

[0402] The styrene used for polymerization of the modified conjugated diene-based polymer was purified by the following steps.

[0403] γ-Alumina, formed into a cylindrical shape of 3 mmϕ × 3 mm, was impregnated with an aqueous solution of palladium chloride with a concentration of 0.6% and dried at 100°C for one day and one night.

[0404] Next, the dried product was subjected to a reduction treatment at a temperature of 400°C for 16 hours under a hydrogen stream to obtain a hydrogenation catalyst with a composition of Pd (0.3%) / γ-Al2O3.

[0405] 2000 g of the obtained hydrogenation catalyst was charged into a tubular reactor, and purified styrene was obtained by circulating crude styrene for 8 hours while maintaining the temperature of the catalyst at 80°C. <Reinigung von normalem Hexan>

[0406] Normal hexane used for the polymerization of the modified conjugated diene-based polymer was purified by the following steps.

[0407] Purified normal hexane was obtained by placing 2000 g of molecular sieve 13-X (Union Showa) into a tubular reactor and circulating crude normal hexane at room temperature for 24 hours. <Reinheitsanalyse von Rohmaterialien (Gesamtverunreinigungen)>

[0408] Quantitative analyses of allenes, acetylenes and amines as impurities in the raw materials were performed.

[0409] Allenes and acetylenes were determined qualitatively and quantitatively by gas chromatography.

[0410] Rt-Alumina BOND / MAPD (Shimadzu Co.) was used as the column.

[0411] In addition, amines were extracted with boric acid and quantified by a titration method to calculate the total impurity (ppm). <(Physical Property 1) Amount of bound styrene>

[0412] Using the modified conjugated diene-based polymer as a sample, 100 mg of the sample was made up to 100 mL with chloroform and dissolved to prepare a measurement sample.

[0413] The amount of bound styrene (mass %) relative to 100 mass % of the modified conjugated diene-based polymer as a sample was measured from the absorption amount of the ultraviolet absorption wavelength (around 254 nm) by the phenyl group of styrene (spectrophotometer manufactured by Shimadzu Co. "UV-2450"). <(Physical Property 2) Microstructure of the butadiene part (1,2-vinyl bond amount)>

[0414] Using the modified conjugated diene-based polymer as a sample, 50 mg of the sample was dissolved in 10 mL of carbon disulfide to obtain a measurement sample.

[0415] Using a solution cell, an infrared spectrum in the range of 600 to 1000 cm -1 and the Hampton method by measuring absorbance at a predetermined wavenumber (the method given in R.R. Hampton, Analytical Chemistry 21, 923 (1949)). The microstructure of the butadiene moiety, i.e., the amount of 1,2-vinyl bonds (mol%), was determined (Fourier transform infrared spectrophotometer "FT-IR230," manufactured by JASCO Co.). <(Physical Property 3) Molecular Weight>

[0416] Using a modified conjugated diene-based polymer as a sample and a GPC meter (product name "HLC-8320GPC", manufactured by Tosoh Co.) in which three columns are connected using polystyrene gel as a filler, the chromatogram was measured using an RI detector (product name "HLC8020", manufactured by Tosoh Co.), and based on a calibration curve obtained using standard polystyrene, the weight-average molecular weight (Mw1), number-average molecular weight (Mn1), molecular weight distribution (Mw1 / Mn1), peak-top molecular weight (Mp1) of the modified conjugated diene-based polymer, and the proportion of the modified conjugated diene-based polymer having a molecular weight of 2 million or more and 5 million or less were determined.

[0417] THF (tetrahydrofuran) was used as the eluent.

[0418] Three products named "TSKgel SuperMultiporeHZ-H" manufactured by Tosoh Co. were connected as columns, and in the preliminary stage, the product named "TSKguardcolumn SuperMP (HZ)-H" manufactured by Tosoh Co. was connected as a guard column.

[0419] A 10 mg sample to be measured was dissolved in 20 mL of THF to obtain a measurement solution, and 10 µL of the measurement solution was injected into a GPC measuring device, and the measurement was carried out under conditions of an oven temperature of 40°C and a THF flow rate of 0.35 mL / min.

[0420] The peak molecular weight (Mp1) was determined as follows.

[0421] In the GPC curve obtained by measurement, the peak detected as the component with the highest molecular weight was selected. For the selected peak, the molecular weight corresponding to the maximum value of the peak was calculated and used as the peak peak molecular weight.

[0422] The proportion of the modified conjugated diene-based polymer having a molecular weight of 2 million or more to 5 million or less was determined as the proportion of the mass of the modified conjugated diene-based polymer having a molecular weight of 2 million or more to 5 million or less with respect to the total mass of the modified conjugated diene-based polymer. <(Physical Property 4) Polymer Mooney Viscosity>

[0423] Using the modified conjugated diene-based polymer as a sample, a Mooney viscometer (product name "VR1132", manufactured by Ueshima Seisakusho Co., Ltd.) was used, and the Mooney viscosity was measured using an L-shaped rotor according to JIS K6300.

[0424] The measured temperature was 100°C.

[0425] First, after preheating the sample to the test temperature for 1 minute, the rotor was rotated at 2 rpm and the torque was measured after 4 minutes to determine the Mooney viscosity (ML (1 + 4) ) to obtain. <(Physical Property 5) Glass Transition Temperature (Tg)>

[0426] Using a modified conjugated diene-based polymer as a sample according to ISO 22768:2006, a differential scanning calorimeter "DSC3200S" manufactured by Mac Science Co., Ltd. was used, and under a helium flow of 50 mL / min, the DSC curve was recorded while raising the temperature from -100°C at 20°C / min, and the peak apex (inflection point) of the DSC difference curve was taken as the glass transition temperature.

[0427] Tg is a value obtained by measuring a sample before adding oil. <(Physical Property 6) Modification rate with respect to the total amount of the conjugated diene-based polymer>

[0428] Using the modified conjugated diene-based polymer as a measurement sample, the chromatogram was measured by applying the adsorption property of the modified basic polymer component to a GPC column with a silica gel as a filler.

[0429] The adsorption amount on the silica column was measured from the difference between the chromatogram measured with the polystyrene column and the chromatogram measured with the silica column of the measurement sample solution containing the measurement sample and the internal standard low molecular weight polystyrene, and the modification rate was determined

[0430] Specifically, it looks like this: Preparation of the sample solution for measurement: 10 mg of the measurement sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF (tetrahydrofuran) to obtain a measurement sample solution.

[0431] GPC measurement conditions using a polystyrene column: Using the product name "HLC-8320GPC" manufactured by Tosoh Co., THF was used as the eluent, 10 µL of a sample solution to be measured was injected into the device under conditions of a column oven temperature of 40°C and a THF flow rate of 0.35 mL / min to obtain a chromatogram using an RI detector. Three products named "TSKgel SuperMultiporeHZ-H" manufactured by Tosoh Co. were connected as the column, and in the pre-stage, the product named "TSKguardcolumn SuperMP (HZ)-H" manufactured by Tosoh Co. was connected as the guard column.

[0432] GPC measurement conditions using a silica column: Using the product name "HLC-8320GPC," manufactured by Tosoh Co., and using THF as the eluent, 50 µL of a sample solution to be measured was injected into the device under conditions of a column oven temperature of 40°C and a THF flow rate of 0.5 mL / min to obtain a chromatogram using an RI detector. The product names "Zorbax PSM-1000S," "PSM-3005," and "PSM-60S" were used as the column, and the product name "DIOL 4.6 × 12.5 mm 5 micron" was used as the guard column in the pre-stage.

[0433] Calculation method of the modification rate: Assuming that the total peak area of ​​the chromatogram using the polystyrene column is 100, the peak area of ​​the sample is P1, the peak area of ​​the standard polystyrene is P2, and the total peak area of ​​the chromatogram using the silica column is 100, the peak area of ​​the sample is P3, and the peak area of ​​the standard polystyrene is P4, the modification rate (mass%) was determined by the following formula: Modification rate (mass−%)=[1−(P2×P3) / (P1×P4)]×100 (In the formula above, P1 + P2 = P3 + P4 = 100) <(Physical Property 7) Modification rate of the low molecular weight component>

[0434] Based on the calibration curve obtained using standard polystyrene according to the measurement in the previous section (physical property 3), the weight-average molecular weight (Mw2), the number-average molecular weight (Mn2), the molecular weight distribution (Mw 2 / Mn2) and the peak molecular weight (Mp2) of the modified conjugated diene-based polymer were measured.

[0435] When multiple peak peaks exist, the peak peak molecular weight (Mp2) was regarded as the molecular weight of the peak peak with the smallest molecular weight, and the height of the graph at molecular weight (molecular weight of the low molecular weight component) obtained by dividing this peak peak molecular weight (Mp2) by 2 was defined as L1.

[0436] The height of the molecular weight (molecular weight of the low molecular weight component) obtained by dividing the highest molecular weight (Mp2) by 2 in the graph measured according to the measurement of (physical property 6) using a silica column was defined as L2.

[0437] The modification rate of the low molecular weight component was calculated by (1 - L2 / L1) × 100. [relative modification rate of low molecular weight component]

[0438] The relative modification rate of the low molecular weight component was calculated by dividing the modification rate of the low molecular weight component (FL) (physical property 7) by the modification rate with respect to the total amount of the conjugated diene-based polymer (FT) (physical property 6). Relative modification rate of the low molecular weight component = (FL / FT) × 100 <(Physical Property 8) Shrinkage Factor (g')>

[0439] Using a modified conjugated diene-based polymer as a sample, a GPC light scattering instrument with a viscosity detector in which three columns were connected with a polystyrene gel as a filler, the chromatogram was measured, and the molecular weight was determined based on the solution viscosity and the light scattering method.

[0440] A mixed solution of tetrahydrofuran and triethylamine (THF in TEA: adjusted by mixing 5 mL of triethylamine with 1 L of tetrahydrofuran) was used as eluent.

[0441] As a column, a guard column: product name "TSKguardcolumn HHR-H", manufactured by Tosoh Co., and a column: product names "TSKgel G6000HHR", "TSKgel G5000HHR", "TSKgel G4000HHR", manufactured by Tosoh Co., were connected and used.

[0442] A GPC light scattering instrument with a viscosity detector (product name "Viscotek TDAmax", manufactured by Malvern) with an oven temperature of 40°C and a THF flow rate of 1.0 mL / min was used.

[0443] A 10 mg sample to be measured was dissolved in 20 mL of THF to prepare a measurement sample solution, and 200 µL of the measurement sample solution was injected into a GPC measuring device to measure the intrinsic viscosity.

[0444] The shrinkage factor (g') was calculated using the obtained intrinsic viscosity and the molecular weight of the sample solution.

[0445] The constant (K, α) in the equation of intrinsic viscosity and molecular weight ([η] = KMα ([η]: intrinsic viscosity, M: molecular weight)) is defined as logK = -3.883, α = 0.711, and regarding the relationship between standard intrinsic viscosity [η]0 and molecular weight M, which is generated by inputting the range from 1000 to 20000000, [η] / [η]0 was calculated at each molecular weight M as the relationship between intrinsic viscosity [η] and intrinsic viscosity [η] to standard intrinsic viscosity [η]0, and the average value was taken as the shrinkage factor (g').

[0446] Furthermore, the shrinkage factor (g') is an average value in the case where M is 1 million or more and 2 million or less. <(Physical Property 9) Silicon Content>

[0447] The silicon content in the modified conjugated diene-based polymer was measured using an ICP mass spectrometer (Agilent Technologies, Agilent 7700s). <(Property 10) Nitrogen content>

[0448] Using a trace amount total nitrogen analyzer (TN-2100H, manufactured by Mitsubishi Chemical Analytech Co., Ltd.), the nitrogen content in the modified conjugated diene-based polymer was measured. [(Preparation Example 1) Synthesis of modified conjugated diene-based polymer (A-1)]

[0449] The internal volume is 10 L, the ratio (L / D) of the internal height (L) to the diameter (D) is 4.0, and it has an inlet at the bottom and an outlet at the top. A pressure tank equipped with a stirrer and a jacket for temperature control was used as the polymerization reactor.

[0450] 1,3-Butadiene at 19.4 g / min, styrene at 10.6 g / min, and n-hexane at 150.0 g / min were mixed with water removed beforehand. The allenes contained in this mixture were 9 ppm, the acetylenes 12 ppm, and the amines 1 ppm. The total impurity was 22 ppm.

[0451] In a static mixer provided in the center of the pipe supplying this mixed solution to the inlet of the reactive group, n-butyllithium was added at 0.104 mmol / min to inactivate the residual impurities, mixed, and then continuously fed to the bottom of the reactive group. 2,2-bis(2-oxolanyl)propane as a polar substance was added at a rate of 0.0216 g / min, and n-butyllithium (referred to as NBL in the tables) as a polymerization initiator was added at a rate of 0.252 mmol / min to the bottom of the reactor, where it was vigorously mixed with a stirrer, and the polymerization reaction continued continuously. The temperature was controlled so that the temperature of the polymerization solution at the reactor outlet was 70°C.

[0452] Only when the polymerization was sufficiently stabilized, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine (abbreviated as "A" in tables) was continuously added to the polymer solution flowing out of the reactor outlet at a rate of 0.043 mmol / min, and the polymer solution to which the modifier was added was mixed and subjected to the modification reaction by passing it through a static mixer.

[0453] Antioxidant (BHT) was continuously added to the modified polymer solution at a rate of 0.055 g / min (n-hexane solution) to achieve 0.2 g per 100 g of polymer, and the coupling reaction was completed. Simultaneously with the antioxidant, oil (JOMO Process NC140, manufactured by JX Nippon Oil & Energy Corporation) was continuously added to achieve 37.5 g per 100 g of polymer and mixed with a static mixer. The solvent was removed by steam stripping to obtain a modified conjugated diene-based polymer (Sample A-1). Table 1 shows the physical properties of Sample A-1. [(Preparation Example 2) Modified Conjugated Diene-Based Polymer (Sample A-2)]

[0454] The modifier was replaced with tris(3-trimethoxysilylpropyl)amine (abbreviated as "B" in the table). Other conditions were the same as in (Preparation Example 1) to obtain a modified conjugated diene-based polymer (Sample A-2). Table 1 shows the physical properties of Sample A-2. [(Preparation Example 3) Modified Conjugated Diene-Based Polymer (Sample A-3)]

[0455] The modifier was replaced with N,N,N'-tris(3-trimethoxysilylpropyl)-N'-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine (abbreviated as "C" in the table), and the amount of n-butyllithium added as a polymerization initiator was set to 0.317 mmol / min, the amount of the polar substance added to 0.027 g / min, and the amount of the modifier to 0.041 mmol / min. Other conditions were the same as in (Preparation Example 1) to obtain a modified conjugated diene-based polymer (Sample A-3). Table 1 shows the physical properties of Sample A-3. [(Preparation Example 4) Modified Conjugated Diene-Based Polymer (Sample A-4)]

[0456] The modifier was replaced with N,N,N',N'-tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine (abbreviated as "D" in the table), and the amount of the modifier was set to 0.033 mmol / min. Other conditions were the same as in (Preparation Example 1) to obtain a modified conjugated diene-based polymer (Sample A-4). Table 1 shows the physical properties of Sample A-4. [(Preparation Example 5) Modified Conjugated Diene-Based Polymer (Sample A-5)]

[0457] The addition amount of n-butyllithium as a polymerization initiator was set to 0.15 mmol / min and the addition amount of a polar substance to 0.0131 g / min, and the modifier was replaced with N-(3-trimethoxysilylpropyl)-2,2-dimethoxy-1-aza-2-silacyclopentane (abbreviated as "E" in the table), and the addition amount of the modifier was set to 0.037 mmol / min. Other conditions were the same as in (Preparation Example 1) to obtain a modified conjugated diene-based polymer (Sample A-5). Table 1 shows the physical properties of Sample A-5. [(Preparation Example 6) Modified Conjugated Diene-Based Polymer (Sample A-6)]

[0458] The addition amount of the polymerization initiator n-butyllithium was set to 0.08 mmol / min and the addition amount of the polar substance to 0.0076 g / min, and the modifier was replaced with N-3-trimethoxysilylpropyltriazole (denoted by "F" in the table), and the addition amount of the modifier was set to 0.041 mmol / min. The other conditions were the same as in (Preparation Example 1) to obtain a modified conjugated diene-based polymer (Sample A-6). Table 1 shows the physical properties of Sample A-6. [(Preparation Example 7) Modified Conjugated Diene-Based Polymer (Sample A-7)]

[0459] The addition rates of 1,3-butadiene and styrene were set to 23 g / min and 5 g / min, respectively, and the addition rate of the polar substance was set to 0.0155 g / min. Other conditions were the same as in Preparation Example 1 to obtain a modified conjugated diene-based polymer (Sample A-7). Table 1 shows the physical properties of Sample A-7. [(Preparation Example 8) Modified Conjugated Diene-Based Polymer (Sample A-8)]

[0460] The addition rates of 1,3-butadiene and styrene were set to 16 g / min and 12 g / min, respectively, and the addition rate of the polar substance was set to 0.024 g / min. Other conditions were the same as in (Preparation Example 4) to obtain a modified conjugated diene-based polymer (Sample A-8). Table 1 shows the physical properties of Sample A-8. [(Preparation Example 9) Modified Conjugated Diene-Based Polymer (Sample A-9)]

[0461] N,N-Dimethylphenyldimethoxysilylpropylamine (abbreviated as "G" in the table) was continuously added as a modifier at a rate of 0.03 mmol / min. Other conditions were the same as in (Preparation Example 6) to obtain a modified conjugated diene-based polymer (Sample A-9). Table 1 shows the physical properties of Sample A-9. [(Preparation Example 10) Modified Conjugated Diene-Based Polymer (Sample A-10)]

[0462] The addition amount of the modifier was set to 0.028 mmol / min. Other conditions were the same as in Preparation Example 1 to obtain a modified conjugated diene-based polymer (Sample A-10). Table 1 shows the physical properties of Sample A-10. [(Preparation Example 11) Modified Conjugated Diene-Based Polymer (Sample A-11)]

[0463] Sample 11 was obtained by kneading Sample A-4 and Sample A-9 in a mass ratio of (Sample A-4) : (Sample A-9) = 2 : 1. Table 2 shows the physical properties of Sample 11. [(Preparation Example 12) Modified Conjugated Diene-Based Polymer (Sample A-12)]

[0464] The internal volume is 10 L, the ratio (L / D) of the internal height (L) to the diameter (D) is 4.0, and it has an inlet at the bottom and an outlet at the top. Two pressure tanks with a stirrer and a jacket for temperature control were coupled together to serve as the polymerization reactor.

[0465] 1,3-Butadiene at 22.3 g / min, styrene at 12.5 g / min, and n-hexane at 214.0 g / min were mixed, with water removed beforehand. The allenes contained in this mixture were 8 ppm, the acetylenes 13 ppm, and the amines 1 ppm. The total impurity was 21 ppm.

[0466] In a static mixer provided in the middle of the pipe supplying this mixed solution to the inlet of the reactive group, n-butyllithium was added at 0.130 mmol / min for inactivation treatment of the residual impurity, mixed, and then continuously supplied to the bottom of the reactive group.

[0467] Further, as a polar substance, the mixed solution of piperidinelithium in which 2,2-bis(2-oxolanyl)propane was prepared in advance as a polymerization initiator at a rate of 0.0347 g / min (abbreviated as "LA-1" in the table) and n-butyllithium (molar ratio of piperidinelithium : n-butyllithium = 0.72 : 0.28, obtained by adjusting piperidine and n-butyllithium in the molar ratio of piperidine : n-butyllithium = 0.72 : 1.00) was supplied at a rate of 0.336 mmol (lithium molar ratio) / min to the bottom of the first polymerization reactor while vigorously mixing with a stirring machine, and the polymerization reaction was continuously continued.

[0468] The temperature was controlled such that the temperature of the polymerization solution at the top outlet of the first reactor was 65°C. By coupling the top of the first reactor and the bottom of the second reactor, the polymer solution was continuously fed from the top of the first reactor to the bottom of the second reactor. The temperature was controlled such that the temperature of the polymer at the top outlet of the second reactor was 70°C.

[0469] Next, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine (abbreviated as "A" in the table) was continuously added as a modifier at a rate of 0.0560 mmol / min to the polymer solution flowing out of the outlet of the second reactor, and the polymer solution to which the modifier was added was mixed and modified by passing it through a static mixer.

[0470] Antioxidant (BHT) was continuously added to the modified polymer solution at a rate of 0.055 g / min (n-hexane solution) to achieve 0.2 g per 100 g of polymer, and the coupling reaction was completed. Simultaneously with the antioxidant, oil (JOMO Process NC140, manufactured by JX Nippon Oil & Energy Corporation) was continuously added to achieve 37.5 g per 100 g of polymer and mixed with a static mixer. The solvent was removed by steam stripping to obtain a modified conjugated diene-based polymer (Sample A-12). Table 2 shows the physical properties of Sample A-12. [(Preparation Comparative Example 1) Modified Conjugated Diene-Based Polymer (Sample A-13)]

[0471] In the purification of 1,3-butadiene, the residence time of the 1,3-butadiene phase in the decanter during the water washing step was set to 10 minutes. The residence time of the 1,3-butadiene phase in the decanter during the polymerization inhibitor removal step was further set to 20 minutes.

[0472] Furthermore, a hydrogenation catalyst of Pd (0.3%) / γ-Al2O3 was obtained in the purification of styrene. 2000 g of the obtained catalyst was charged into a tubular reactor, and crude styrene, which was circulated and purified for four hours, was used while maintaining the catalyst temperature at 80°C. For the purification of normal hexane, the same purification procedure as in Preparation Example 1 was performed.

[0473] In a mixture of 1,3-butadiene, styrene, and n-hexane, the allenes contained 25 ppm, the acetylenes 20 ppm, and the amines 9 ppm. The total impurity was 54 ppm. A modified conjugated diene-based polymer (Sample A-13) was obtained in the same manner as in (Preparation Example 1), except for the use of these ingredients. Table 1 shows the physical properties of Sample A-13. [(Preparation Comparative Example 2) Modified Conjugated Diene-Based Polymer (Sample A-14)]

[0474] The addition amount of the modifier was set to 0.020 mmol / min. Other conditions were the same as in Preparation Example 1 to obtain a modified conjugated diene-based polymer (Sample A-14). Table 2 shows the physical properties of Sample A-14. [(Preparation Comparative Example 3) Modified Conjugated Diene-Based Polymer (Sample A-15)]

[0475] N,N-Dimethylphenyldimethoxysilylpropylamine (abbreviated as "G" in the table) was continuously added as a modifier at a rate of 0.03 mmol / min. The other conditions were the same as in (Preparation Comparative Example 1) to obtain a modified conjugated diene-based polymer (Sample A-15). Table 2 shows the physical properties of Sample A-15. [(Preparation Comparative Example 4) Modified Conjugated Diene-Based Polymer (Sample A-16)]

[0476] A temperature-controlled autoclave with an internal volume of 10 L, a stirrer, and a jacket was used as a reactor, and 518 g of 1,3-butadiene, 282 g of styrene, 5600 g of normal hexane, and 0.53 g of polar substance purified in the same manner as in Preparation Example 1 were charged into the reactor, and after maintaining the internal temperature of the reactor at 55°C, 8.75 mmol of n-butyllithium was introduced into the reactor as a polymerization initiator.

[0477] After the start of the reaction, the temperature in the reactor reached 83°C due to the heat generated by the polymerization.

[0478] The polymerization reaction was stopped when 1 minute had passed after the reactor temperature began to drop.

[0479] When the temperature in the reactor was 83°C after completion of the polymerization reaction, 4.375 mmol of 3-(4-methylpiperazin-1-yl)propyltriethoxysilane (abbreviated as "H" in the table) was added in the solution phase, stirred for 5 minutes, and the modification reaction was carried out. 0.2 g of an antioxidant (BHT) based on 100 g of polymer was added to the modified polymer solution to obtain a modified conjugated diene-based polymer (Sample A-16). No oil was added.

[0480] Table 2 shows the physical properties of sample A-16.

[0481] Property 3 in Table 2 is an analytical value for the peak with the lowest molecular weight. Furthermore, the shrinkage factor (g') could not be calculated because too few components with a molecular weight in the range of 1 million to 2 million were present. [(Preparation Example 13) Modified Conjugated Diene-Based Polymer (Sample A-17)]

[0482] By mixing the polymer obtained in Preparation Comparative Example 1 and the polymer obtained in Preparation Comparative Example 4 in a mass ratio of (Preparation Comparative Example 1) : (Preparation Comparative Example 4) = 2 : 1, Sample A-17 was obtained. Table 2 shows the physical properties of Sample A-17. [(Preparation Example 14) Modified Conjugated Diene-Based Polymer (Sample A-18)]

[0483] By mixing the polymer obtained in Preparation Comparative Example 2 and the polymer obtained in Preparation Comparative Example 4 in a mass ratio of (Preparation Comparative Example 2) : (Preparation Comparative Example 4) = 2 : 1, Sample A-18 was obtained. Table 2 shows the physical properties of Sample A-18. [(Embodiments 1 to 19) and (Comparative Examples 1 to 6)]

[0484] Samples A-1 to A-18 shown in Tables 1 and 2 were regarded as (A) modified conjugated diene-based polymers, and NR1, NR2, IR1 and IR2 shown in Tables 3 to 5 below were regarded as (B) component, and a modified conjugated diene-based polymer composition containing each raw rubber was obtained according to the following formulation (parts by mass) based on 100 parts by mass of the rubber component ((A) + (B)).

[0485] Furthermore, the proportion of (A) and (B) in 100 parts by mass of the rubber component is shown in Tables 3 to 5.

[0486] NR1 represents natural rubber "SIR10", NR2 represents natural rubber "RSS # 2", IR1 represents polyisoprene "IR2200" (cis-1,4 bond content 95% or more, manufactured by JSR), and IR2 represents polyisoprene "Cariflex IR0307" (cis-1,4 bond content 90% or more, manufactured by Kraton).

[0487] With respect to the rubber component ((A) + (B)) = 100 parts by mass, the following materials were added to prepare rubber compositions using a modified conjugated diene-based polymer composition as a material.

[0488] (C) Component silicon dioxide 1 (product name "Ultrasil 7000GR", manufactured by Evonik, Degussa AG, specific nitrogen adsorption surface area 170 m 2 / g): 50.0 parts by mass

[0489] Silicon dioxide 2 (product name "Zeosil Premium 200MP", manufactured by Rhodia, specific nitrogen adsorption surface 220 m 2 / g): 25.0 parts by mass

[0490] Carbon black (product name "Seast KH (N339)", manufactured by Tokai Carbon Co., Ltd.): 5.0 parts by mass

[0491] Silane coupling agent (product name "Si75", manufactured by Evonik, Degussa AG, bis(triethoxysilylpropyl)disulfide): 6.0 parts by mass

[0492] S-RAE oil (product name "Process NC140", manufactured by JX Nippon Oil & Energy Co.): 37.5 parts by mass Zinc bloom: 2.5 parts by mass Stearic acid: 1.0 parts by mass Anti-aging agent (N-(1,3-dimethylbutyl)-N'phenyl-p-phenylenediamine): 2.0 parts by mass Sulfur: 2.2 parts by mass Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazylsulfinamide): 1.7 parts by mass Vulcanization accelerator 2 (diphenylguanidine): 2.0 parts by mass Total: 234.9 parts by mass

[0493] The above materials were kneaded by the following method to obtain a rubber composition.

[0494] Using a closed-type kneading machine (with an internal volume of 0.3 L) equipped with a tempering device, raw rubber (samples A-1 to A-18), filler (silica 1, silica 2, carbon black), silane coupling agent, process oil, zinc bloom, and stearic acid were kneaded as first-stage kneading under the conditions of a filling rate of 65% and a rotor speed of 30 to 50 rpm.

[0495] The temperature of the closed mixer was controlled and each rubber composition (compound) was obtained at a discharge temperature of 155 to 160°C. (Rating 1) Torque rise time

[0496] During kneading in the first stage and after starting kneading of the closed kneader, the time required until the torque increased to a constant value after the increase was measured.

[0497] Each measured value was indexed with the result of Comparative Example 1 as 100.

[0498] A smaller index indicates a shorter rise time and better formability. (Rating 2) Film processability

[0499] As described above, the sheet composition was machined with an open roll set at 70°C using the rubber composition (compound) obtained by kneading in the first stage.

[0500] The film condition of the obtained film-like composition was visually evaluated according to the following criteria in five stages.

[0501] A higher score indicates better slide editability. 5: Good uniformity in roll work, smooth film skin and no jagged film edges. 4: Although the unit is good in rolling work, the film skin is a bit rough and the film edge is also slightly jagged. 3: When working with the roller, the unit is a bit poor, the film skin is slightly rough and the film edge is slightly jagged. 2: When working with the roller, the unit is a bit bad, the film skin is rough and the film edge is jagged. 1: The unity of the roll work is poor, the film skin is rough and the film edge is also jagged.

[0502] Next, after kneading in the first stage, as kneading in the second stage, the compound obtained above was cooled to room temperature and then an anti-aging agent was added and kneaded again to improve the dispersion of silicon dioxide.

[0503] In this case, too, the discharge temperature of the compound was adjusted to 155 to 160°C by controlling the temperature of the mixer.

[0504] After cooling, sulfur and vulcanization accelerators 1 and 2 were added as a third kneading and kneaded with an open roll set at 70°C.

[0505] It was then molded and vulcanized using a vulcanizing press at 160°C for 20 minutes. The rubber composition before vulcanization and the rubber composition after vulcanization were evaluated. Specifically, the evaluation was conducted using the following method.

[0506] The evaluation results are shown in Table 5 and Table 6. (Rating 3) Mooney viscosity of the compound

[0507] The rubber composition obtained after kneading in the second stage was used as a sample, and the Mooney viscosity was measured using a Mooney viscometer (product name "VR1132", manufactured by Ueshima Seisakusho Co., Ltd.) according to JIS K6300 and using an L-shaped rotor. This is considered the Mooney viscosity of the compound.

[0508] The measured temperature was 100°C.

[0509] First, after preheating the sample to the test temperature for 1 minute, the rotor was rotated at 2 rpm and the torque was measured after 4 minutes to determine the Mooney viscosity (ML (1 + 4) ) to obtain.

[0510] Each measured value was indexed with the result for the rubber composition of Comparative Example 1 as 100. A smaller index indicates better processability. (Rating 4) Viscoelastic parameters

[0511] The rubber composition after vulcanization was measured for viscoelastic parameters in a torsional mode using a viscoelasticity tester "ARES" manufactured by Rheometrics Scientific. Each measured value was indexed with the result for the rubber composition of Comparative Example 1 as 100. The tanδ value measured at 0°C with a frequency of 10 Hz and a distortion of 1% was used as an index for wet skid resistance. It shows that the larger the value, the better the wet skid resistance. The tanδ value measured at 50°C with a frequency of 10 Hz and a distortion of 3% was also used as an index for low hysteresis loss. It shows that the larger the value, the better the low hysteresis loss property. (Rating 5) Tensile strength, tensile elongation

[0512] The rubber composition after vulcanization was measured for tensile strength and tensile elongation at break according to the tensile test method of JIS K6251, and each measured value was indexed to the result of Comparative Example 1 as 100. It shows that the larger the value, the better the breaking strength. (Rating 6) Wear resistance

[0513] Regarding the rubber composition after vulcanization, the wear amount was measured at a load of 44.4 N and 1000 revolutions according to JIS K6264-2 using an Akron wear tester (manufactured by Yasuda Seiki Seisakusho). Each measured value was indexed to the result of Comparative Example 1 as 100. This indicates that the larger the index, the better the wear resistance. [Table 3] (mass part) Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 mixed rubber component (A) Component Modified conjugated diene-based polymer Sample number A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 Mass part 70 70 70 70 70 70 70 70 (B) Component NR1 30 30 30 30 30 30 30 30 NR2 0 0 0 0 0 0 0 0 IR1 0 0 0 0 0 0 0 0 IR2 0 0 0 0 0 0 0 0

[0230] [Table 4] (mass part) Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 mixed rubber component (A) Component Modified conjugated diene-based polymer Sample number A-9 A-10 A-11 A-12 A-17 A-18 A-1 A-1 A-1 Mass part 70 70 70 70 70 70 70 70 70 (B) Component NR1 30 30 30 30 30 30 0 0 0 NR2 0 0 0 0 0 0 30 0 0 IR1 0 0 0 0 0 0 0 30 0 IR2 0 0 0 0 0 0 0 0 30

[0231] [Table 5] (mass part) Example 18 Example 19 Comparison example 1 Comparison example 2 Comparison example 3 Comparison example 4 Comparison example 5 Comparison example 6 mixed rubber component (A) Component Modified conjugated diene-based polymer Sample number A-1 A-1 A-13 A-14 A-15 A-16 A-1 A-1 Mass part 50 30 70 70 70 70 95 25 (B) Component NR1 50 70 30 30 30 30 5 75 NR2 0 0 0 0 0 0 0 0 IR1 0 0 0 0 0 0 0 0 IR2 0 0 0 0 0 0 0 0

[0232] [Table 6] No. Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 (Rating 1) Torque rise time index 87 88 95 98 93 91 93 96 (Rating 2) Film processability index 4 4 5 4 4 3 3 3 (Rating 3) Mooney viscosity of the compound (100°C) index 95 94 89 95 113 128 98 93 (Rating 4) 50°C tanδ (distortion of 3%) index 96 98 86 83 99 105 82 95 (Rating 4) 0°C tanδ (distortion of 1%) index 102 102 112 115 100 94 113 137 (Rating 5) Tensile strength index 101 102 103 109 104 107 105 102 (Rating 5) Tensile elongation at break index 103 105 104 108 105 108 105 103 (Rating 6) Wear resistance index 105 107 110 115 108 111 112 110

[0233] [Table 7] No. Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 Example 17 (Rating 1) Torque rise time index 97 95 95 77 82 100 89 93 95 (Rating 2) Film processability index 3 5 4 2 4 3 4 5 5 (Rating 3) Mooney viscosity of the compound (100°C) index 98 99 96 97 101 105 96 94 98 (Rating 4) 50°C tanδ (distortion of 3%) index 102 105 85 90 82 90 97 97 96 (Rating 4) 0°C tanδ (distortion of 1%) index 95 96 112 108 110 112 100 102 101 (Rating 5) Tensile strength index 92 98 107 104 98 89 108 102 102 (Rating 5) Tensile elongation at break index 94 96 106 105 98 86 110 101 102 (Rating 6) Wear resistance index 96 99 110 108 96 87 110 103 102

[0234] [Table 8] No. Example 18 Example 19 Comparison example 1 Comparison example 2 Comparison example 3 Comparison example 4 Comparison example 5 Comparison example 6 (Rating 1) Torque rise time index 92 96 100 118 125 68 83 128 (Rating 2) Film processability index 4 3 4 3 3 3 5 3 (Rating 3) Mooney viscosity of the compound (100°C) index 98 101 100 111 105 103 96 98 (Rating 4) 50°C tanδ (distortion of 3%) index 102 105 100 112 106 64 93 108 (Rating 4) 0°C tanδ (distortion of 1%) index 99 96 100 88 89 118 105 90 (Rating 5) Tensile strength index 103 104 100 90 93 82 93 103 (Rating 5) Tensile elongation at break index 105 107 100 86 92 83 93 106 (Rating 6) Wear resistance index 107 110 100 88 89 85 91 108

[0514] As shown in Tables 6 to 8, it was confirmed that, with respect to the rubber compositions of the working examples, as compared with the rubber compositions of the comparative examples, excellent workability is obtained when used as a vulcanizate, torque is well applied particularly when kneading with the filler, a rubber composition having good filler dispersibility can be obtained in a short time, the excellent balance between the wet skid resistance and the low hysteresis loss when used as a vulcanizate, and also excellent durability such as wear resistance and fracture strength are obtained. [Industrial applicability]

[0515] The rubber composition according to the present invention has industrial applicability in fields such as tire treads, automotive interior / exterior products, anti-vibration rubbers, belts, shoes, foams, and various industrial products.< / hydrierungsschritt> < / modifizierungsreaktionsschritt> < / polymerisationsinitiator> < / polymerisationsschritt> < / stickstoff> < / ende> < / modifikatorrest> < / schrumpffaktor> < / molekulargewichtsverteilung> < / modifizierungsrate>

Claims

[1] Rubber composition containing: (A) 100 parts by mass of a modified conjugated diene-based polymer obtained by reacting a conjugated diene-based polymer with a nitrogen-containing compound, in which the weight-average molecular weight 20 × 10 4 or more and 300 × 10 4 or less and the molecular weight distribution Mw / Mn is 1.6 or more and 4.0 or less, wherein the modification rate with respect to the total amount of the conjugated diene-based polymer, determined from a chromatogram obtained by gel permeation chromatography (GPC), is 50 mass% or more, and the modification rate of a component having a molecular weight that is half the molecular weight at the peak tip in the chromatogram obtained by gel permeation chromatography (GPC) or, when multiple peak tips are present, at the peak tip with the minimum molecular weight, half or more of the modification rate with respect to the total amount of the conjugated diene-based polymer, (B) 10 to 250 parts by mass of natural rubber having a microgel content of 5 to 24 mass% and / or polyisoprene rubber having a 1,4-cis bond amount of 90% or more, and (C) 5 to 150 parts by mass of a silicon dioxide-containing filler. [2] The rubber composition according to claim 1, wherein with respect to the (A) modified conjugated diene-based polymer, the shrinkage factor (g') by 3D-GPC is 0.86 or more and 1.0 or less. [3] The rubber composition according to claim 1, wherein with respect to the (A) modified conjugated diene-based polymer, the shrinkage factor (g') by 3D-GPC is 0.30 or more and less than 0.

86. [4] The rubber composition according to claim 1, wherein with respect to the (A) modified conjugated diene-based polymer, the shrinkage factor (g') by 3D-GPC is 0.30 or more and 0.70 or less. [5] The rubber composition according to any one of claims 1 to 4, wherein the polymerization initiator residue of the (A) modified conjugated diene-based polymer does not contain nitrogen. [6] A rubber composition according to any one of claims 1 to 5, wherein the (B) component is a natural rubber. [7] A rubber composition according to any one of claims 1 to 5, wherein the (B) component is a polyisoprene rubber. [8] A process for producing the rubber composition according to claim 1, wherein (A) 100 parts by mass of the modified conjugated diene-based polymer, (B) 10 to 250 parts by mass of natural rubber and / or polyisoprene rubber, and (C) 5 to 150 parts by mass of the silicon dioxide-containing filler are kneaded. [9] A process for producing the rubber composition according to claim 8, wherein after kneading the (A) 100 parts by mass of the modified conjugated diene-based polymer and the (C) silica-containing filler, the resulting kneaded product and the (B) natural rubber and / or polyisoprene rubber are kneaded. [10] A vulcanized product obtained by using the rubber composition according to any one of claims 1 to 7. [11] Use of the rubber composition according to any one of claims 1 to 7 for producing a tire.