JP6041530B2 - Modified butadiene polymer, method for producing modified butadiene polymer, rubber composition, and tire - Google Patents

Description

  The present invention relates to a modified butadiene polymer, a method for producing a modified butadiene polymer, a rubber composition, and a tire.

Conventionally, it has been important in the field of rubber compositions to balance various characteristics such as low fuel consumption, wear resistance, wet skid, and processability at a high level.
In such a rubber composition, for the purpose of improving the affinity between the polymer used as the raw material rubber and the filler, for example, there is a method of introducing a predetermined functional group into the butadiene polymer that is the raw material rubber and modifying it. Various studies have been made.
As the modification method, for example, a method of introducing a functional group at the start end or the end end using anion living polymerization or at both of them has been proposed (see, for example, Patent Documents 1 to 3).
Other modification methods include a method of copolymerizing a monomer having a functional group (see, for example, Patent Document 4), and a method of introducing a functional group by reacting with a double bond of the main chain after polymerization. A method has been proposed (see, for example, Patent Documents 5 and 6).

JP 62-149708 A JP 2003-171418 A International Publication No. 08/013090 Pamphlet JP 2010-077386 JP-A-53-119831 JP 2004-346140 A

  However, the modified butadiene polymer produced by the conventional modification methods does not have an effect of improving the affinity with the filler when used in the rubber composition. The reason is considered to be that the number of functional groups on the modified butadiene-based polymer is small, and the position of the functional group on the polymer is not appropriate.

  The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a novel modified butadiene polymer in which a sufficient amount of functional groups are introduced at a specific site and a method for producing the same. To do. This improves the processability of the rubber composition containing the modified butadiene-based polymer and maximizes the reinforcing effect of the filler, so that the tensile properties of the vulcanized compound are good, the fuel efficiency is high, and the rigidity is high. An object is to provide a rubber composition and a tire that are high and have excellent wear resistance.

As a result of intensive studies in order to solve the problems of the prior art, the present inventors have studied a method for introducing a functional group into a butadiene-based polymer, and are sufficient for a specific part of the molecule of the modified butadiene-based polymer. It has been found that the above-mentioned problems can be solved by introducing a sufficient amount of functional groups, and the present invention has been completed.
That is, the present invention is as follows.

[1]
  1,3-butadiene is polymerized using an alkali metal compound or alkaline earth metal compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group as a polymerization initiator, or 1,3 A polymerization step of copolymerizing butadiene and a monomer copolymerizable with 1,3-butadiene to obtain a butadiene-based polymer having an active terminal and a polymerization initiation terminal having the functional group;
  A compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group at the active terminal of the butadiene-based polymer, or at least selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group A terminal modification step of reacting a compound that forms one type of functional group to introduce the functional group;
  A silicon compound having at least one functional group selected from the group consisting of a vinyl group in the main chain of the butadiene-based polymer and an amino group, an alkoxysilyl group, or a hydroxyl group, or an amino group, an alkoxysilyl group, or a hydroxyl group A main chain modification step of modifying the main chain by hydrosilylation reaction with a silicon compound forming at least one functional group selected from the group;
  Including
  In the modified butadiene-based polymer, the amount of 1,2-vinyl bonds in all butadiene units is 25 to 80 mol%.
  A method for producing a modified butadiene-based polymer.
[2]
  1,3-butadiene is polymerized using a polyfunctional initiator, or 1,3-butadiene and a monomer copolymerizable with 1,3-butadiene are copolymerized to have an active end. A polymerization step for obtaining a butadiene-based polymer;
  A compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group at the active terminal of the butadiene-based polymer, or at least selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group A terminal modification step of reacting a compound that forms one type of functional group to introduce the functional group at two or more ends;
  A silicon compound having at least one functional group selected from the group consisting of a vinyl group in the main chain of the butadiene-based polymer and an amino group, an alkoxysilyl group, or a hydroxyl group, or an amino group, an alkoxysilyl group, or a hydroxyl group A main chain modification step of modifying the main chain by hydrosilylation reaction with a silicon compound forming at least one functional group selected from the group;
  Including
  In the modified butadiene-based polymer, the amount of 1,2-vinyl bonds in all butadiene units is 25 to 80 mol%.
  A method for producing a modified butadiene-based polymer.
[3]
  100 parts by mass of raw rubber containing 20 parts by mass or more of the modified butadiene polymer obtained by the production method according to [1] or [2] and 5 to 200 parts by mass of filler are mixed.
  A method for producing a rubber composition.
[4]
  30 to 100% by mass of the filler is silica.
  [3] The method for producing a rubber composition according to [3].
[5]
  Further cross-linking treatment,
  [3] or the method for producing a rubber composition according to [4].
[6]
  Vulcanization molding of the rubber composition according to [5],
  Tire manufacturing method.

  According to the present invention, a modified butadiene polymer having a sufficient amount of functional groups introduced at a specific site can be obtained. In addition, when blended with a filler to form a crosslinked rubber composition, the effect of filler dispersibility is superior compared to a modified butadiene polymer in which a functional group is introduced only at the polymer end or only at the main chain, and tensile properties It is possible to obtain a rubber composition having a good balance of various properties with a good balance, various fuel consumption performances, excellent wear resistance, excellent rigidity, and good workability.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following description, It can implement by changing variously within the range of the summary.

[Modified butadiene polymer]
The modified butadiene polymer of the present embodiment has two or more terminals modified with a modifying group having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group,
Furthermore, the vinyl group of the main chain is modified with a silicon-modified group having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group.

(Butadiene polymer)
In this embodiment, the butadiene polymer is a 1,3-butadiene polymer or a copolymer of 1,3-butadiene and a monomer copolymerizable with the 1,3-butadiene. Can be mentioned. The monomer copolymerizable with 1,3-butadiene is not particularly limited, and specific examples include conjugated diene compounds other than 1,3-butadiene, vinyl aromatic compounds, acrylonitrile, acrylic acid compounds, and the like. It is done. These may be used alone or in combination of two or more. Among these, as another monomer which can be copolymerized, a conjugated diene compound and an aromatic vinyl compound are preferable.

  The conjugated diene compound is not particularly limited, and specifically, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 1,3-hexadiene, 1,3-cyclohexadiene, and the like. Is mentioned. Further, the aromatic vinyl compound is not particularly limited, and specifically, styrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, divinylbenzene, 1,1-diphenylethylene, 1-vinyl. Naphthalene, 2-vinylnaphthalene, pN, N-diethylaminomethylstyrene, pN, N-diethyl-2-aminoethylstyrene and the like can be mentioned. Among these, isoprene and styrene are preferable.

  The butadiene polymer as described above is not particularly limited, and specific examples thereof include polybutadiene, butadiene-isoprene copolymer, butadiene-styrene copolymer, and butadiene-isoprene-styrene copolymer. Moreover, in a butadiene-type polymer, it is preferable that a butadiene unit is 50-100 mass% of the whole polymer.

(Modified end and main chain)
The modified butadiene polymer of the present embodiment is modified by introducing functional groups into two or more terminals and main chain of the butadiene polymer obtained from the above monomer.
In the present invention, the two or more terminals into which a functional group is introduced include both a starting terminal and a terminal terminal when a monofunctional initiator is used, and at least two or more terminals when a polyfunctional initiator is used. Means the terminal end of That is, in the case of a linear polymer, it means both ends, and in the case of a branched polymer, it means 2 or more, preferably 3 or more.
That is, two or more terminals (including the starting terminal and the terminal terminal) are modified with a modifying group having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, The vinyl group is modified with a silicon-modified group having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group.

(Modified group / silicon modified group)
In the present embodiment, the modified group and the silicon modified group have at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, and are attached to the vinyl terminal of the polymer terminal or the polymer main chain. There is no particular limitation as long as it is a bonded group. Specific examples of such a modifying group include a group derived from a polymerization initiator and introduced into the polymerization initiation terminal of a butadiene-based polymer, and a group derived from the following modifier and introduced into the terminal. It is done. Specific examples of the silicon-modified group include groups derived from the following silicon compounds and introduced into the vinyl group of the main chain of the butadiene polymer.

In this embodiment, the modifying group having an amino group is not particularly limited, and specifically, an amino group having no substituent represented by —NH ₂ , —NHR (where R represents a substituent). 1-substituted amino group, an imino group bonded to different carbons represented by —NH—, —NR ₂ , a 2-substituted amino group represented by (R represents a substituent), or ═N— And a modifying group having various functional groups containing a nitrogen atom, such as an imino group bonded to the same carbon represented by a double bond.

  In the present embodiment, the modifying group having an alkoxysilyl group is not particularly limited, and specific examples thereof include a modifying group having a functional group represented by the general formula R′—O—Si. Here, R ′ is not particularly limited, but is a hydrocarbon group, preferably a saturated / unsaturated hydrocarbon group having 1 to 10 carbon atoms, and among them, an alkyl group, an alkenyl group, a cycloalkyl group It is preferably either a group or an aryl group. Among these, R ′ is preferably an alkyl group having 1 to 4 carbon atoms.

(Number average molecular weight (Mn) / Molecular weight distribution (Mw / Mn))
The number average molecular weight (Mn) in terms of polystyrene obtained by gel permeation chromatography (GPC) measurement of the modified butadiene polymer of the present embodiment is preferably 20,000 to 2,000,000, more preferably. Is from 100,000 to 1,500,000, more preferably from 150,000 to 1,000,000. If the number average molecular weight is within this range, the strength when the rubber composition of the present embodiment is vulcanized can be further improved, and the processability can be further improved. Specifically, it can be measured by the method described in “(5) Molecular weight” in Examples described later.

  The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the modified butadiene polymer of the present embodiment, that is, the molecular weight distribution (Mw / Mn) is preferably from the viewpoint of the physical properties of the vulcanizate. It is 1.00 to 3.50, More preferably, it is 1.10 to 3.00, More preferably, it is 1.15 to 2.50.

  When the molecular weight distribution Mw / Mn is less than 1.8, the weight average molecular weight is generally 600,000 or less, and it is treated as a non-oil-extended polymer, and is characterized by low hysteresis loss in vulcanized rubber applications. Therefore, it is suitable as a raw material rubber for a fuel-saving tire tread. On the other hand, when the molecular weight distribution Mw / Mn is 1.8 or more, it is generally handled as an oil-extended polymer, and is characterized by wet skid resistance, dry skid resistance, etc. for vulcanized rubber applications. It is suitable as a raw material rubber for a high-performance tire tread having excellent fuel economy.

  The modified butadiene-based polymer of the present embodiment is not particularly limited, but the modification rate is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably 70% by mass or more. . Here, the “modification rate” refers to the mass% of the polymer having a modifying group in the modified butadiene-based polymer. Such a modification | denaturation rate is calculated | required by the adsorption amount to the column of a gel permeation chromatography (GPC) measurement using a silica particle packed column.

  As a method for quantifying the modification rate of the modified butadiene polymer having a functional group component, a method of measuring by a chromatography capable of separating the functional group-containing modified component and the non-modified component can be used. As a method using this chromatography, there is a method in which a GPC column using a polar substance such as silica adsorbing a functional group component as a filler is used and the internal standard of the non-adsorbed component is used for comparison. More specifically, it can be measured by the method described in “(6) Modification rate” in Examples described later.

  When the modified butadiene polymer of the present embodiment is a copolymer of 1,3-butadiene and a vinyl aromatic compound, the amount of bonded aromatic vinyl is not particularly limited, but may be 3 to 50% by mass. Preferably, it is 5-45 mass%, More preferably, it is 15-40 mass%. Here, the “bound aromatic vinyl amount” refers to the mass% of the vinyl aromatic unit (monomer) in the modified butadiene polymer.

  In particular, when the rubber composition containing the modified butadiene polymer of the present embodiment is used as a vulcanized product and used in a tire tread, the amount of bonded aromatic vinyl in the modified butadiene polymer is 20 to 40% by mass. Is preferred. In this case, when the tire tread is composed of a cap tread and an under tread, it is preferable to use the modified butadiene-based polymer of the present embodiment for the cap tread which is a grounding side.

  When the amount of bonded aromatic vinyl is within the above range, the vulcanizate has an excellent balance between low hysteresis loss and wet skid resistance when used in tire tread applications, and also satisfies wear resistance and fracture strength. Can be obtained.

Here, the amount of bonded aromatic vinyl can be measured by ultraviolet absorption of a phenyl group. Specifically, it can be measured by the method described in “(1) Amount of bound styrene” in Examples described later.
When used for an under tread, it is preferable to use a modified polybutadiene having a lower exothermic property.

  The amount of 1,2-vinyl bonds in all butadiene units in the modified butadiene-based polymer is not particularly limited, but is preferably 10 to 80 mol%, more preferably 25 to 70 mol%, and 30 More preferably, it is -65 mol%. Here, the “1,2-vinyl bond amount” means the ratio of 1,2-added butadiene units in all 1,2-added and 1,4-added butadiene units. Say. The 1,2-added butadiene unit has a vinyl group. Therefore, the amount of 1,2-vinyl bonds is related to the amount of vinyl groups in the main chain of the butadiene-based polymer.

  When the 1,2-vinyl bond amount is in the above range, the rubber composition containing the modified butadiene polymer of the present embodiment is used as a vulcanized product, and when used for a tire tread, low hysteresis loss and wet skid. The balance of resistance is further improved, and high wear resistance and breaking strength can be obtained.

  Here, when the modified butadiene-based polymer is a copolymer of butadiene and styrene, a 1,2-vinyl bond is obtained by the method of Hampton (RR Hampton, Analytical Chemistry, 21, 923 (1949)). The amount can be determined. More specifically, it can be measured by the method described in “(2) Microstructure of butadiene (1,2-vinyl bond amount)” in Examples described later.

The glass transition temperature of the modified butadiene polymer of the present embodiment is not particularly limited, but is preferably in the range of −80 ° C. to 0 ° C., and more preferably in the range of −50 ° C. to −20 ° C. Thereby, when the rubber composition containing the modified butadiene-based polymer of the present embodiment is used as a vulcanized product and used for tire tread applications, the balance between low hysteresis loss and wet skid resistance is good. .
The glass transition temperature can be measured by recording a DSC curve while raising the temperature in a predetermined temperature range according to ISO 22768: 2006, and using the peak top (Infection point) of the DSC differential curve as the glass transition temperature. Can be measured by the method described in “(4) Glass transition temperature (Tg)” of Examples described later.

  The butadiene-based polymer of the present embodiment is not particularly limited, but preferably has a structure in which the amount of 1,2-vinyl bonds in the butadiene unit has a distribution along the main chain. Here, “having distribution along the main chain” means that 1,2-added butadiene units are distributed in the main chain of the butadiene-based polymer. With such a structure, in the main chain modification step described later, the hydrosilylation reaction is higher on the side where the amount of 1,2-vinyl bonds is large (where the 1,2-added butadiene units are dense). It is performed at a frequency, and a slope is obtained in a desired range in the functional group modification degree of the main chain. Thereby, various desired modified structures are obtained in combination with terminal modification. That is, a modified butadiene polymer designed to give many specific functional groups on one side of a polymer molecule and many other specific functional groups on the other side in combination with terminal-modified functional groups. It is possible to obtain. Specifically, a 2-substituted amino group is added to the polymerization initiation terminal, and the main chain on the polymerization initiation side is used as a high vinyl bond amount to modify the main chain with a 2-substituted amino group, and an alkoxysilyl group is added to the terminal terminal It is possible to obtain a modified butadiene polymer having a design of

  The method for obtaining a structure having a distribution along the main chain in the 1,2-vinyl bond amount of the butadiene unit is not particularly limited, but specifically, there is a method of changing the temperature during polymerization. Can be mentioned. That is, 1,2-addition predominates at a low temperature during polymerization, resulting in a high vinyl bond content, and 1,4-addition predominates at a high temperature during polymerization, so a low vinyl bond content tends to be achieved. Specifically, in the polymerization, the distribution of the amount of vinyl bonds can be given along the main chain by polymerizing while raising the temperature. For example, when the polymerization starting temperature is 30 ° C. to the maximum temperature 90 ° C., the vinyl bond amount can be continuously changed from 70 mol% to 30 mol% when the kind and amount of the vinylizing agent are appropriately set. In addition, as another method, a method of adding / increasing the vinylizing agent during polymerization may be mentioned. Thereby, it is possible to change from a low vinyl bond amount to a high vinyl bond amount. In this method, the vinyl bond amount can be changed continuously or stepwise from 10 mol% to 80 mol%. Here, examples of the “vinylating agent” include polar compounds described below.

  When the modified butadiene polymer of the present embodiment is a copolymer, it is preferably a butadiene-styrene copolymer. The copolymer of butadiene units and styrene units may be a random copolymer or a block copolymer. The random copolymer may be a uniform random copolymer or a tapered random copolymer. The block copolymer may be a complete block copolymer or a tapered block copolymer partially including a random structure. Each can be selected according to the purpose.

  When the rubber composition containing the modified butadiene polymer of the present embodiment is used as a tire material, the modified butadiene polymer is a butadiene-styrene random copolymer. Is preferred. The butadiene-styrene copolymer preferably has a random structure and a bound styrene content of 3 to 50% by mass. Thereby, the calorific value is small with respect to repetitive deformation, and can meet the required performance of the tire.

  The butadiene-styrene random copolymer preferably has little or no block styrene having a chain length of 30 or more styrene units. Specifically, when the modified butadiene-based polymer is a butadiene-styrene random copolymer, the method described in Kolthoff (IM Kolthoff, et al., J. Polym. Sci. 1, 429 (1946) is used. The modified butadiene polymer is decomposed by the described method), and it can be measured by a known method of analyzing the amount of polystyrene insoluble in methanol (block styrene amount). At this time, the amount of block styrene is preferably 10% by mass or less and more preferably 5% by mass or less with respect to the total amount of the butadiene-based polymer.

  Further, in detail, the modified butadiene polymer can be decomposed by ozonolysis method known as Tanaka et al. (Polymer, 22, 1721 (1981)), and styrene chain distribution can be analyzed by GPC. . In this case, the isolated styrene, that is, the styrene having one styrene unit chain is 40% by mass or more based on the total amount of bound styrene, and the long chain block styrene, that is, the styrene having eight or more styrene unit chains is all. It is preferably 10% by mass or less based on the amount of bound styrene.

  When the rubber composition containing the modified butadiene polymer according to the present embodiment is used as a vulcanized rubber composition and a material for footwear, the modified butadiene polymer preferably has a block structure. This meets the required performance for footwear, particularly for shoe soles. It has a particularly high modulus and a hard feel. In that case, it is preferable that there are many components whose chain length of a styrene unit is 30 or more. Specifically, when the modified butadiene-based polymer is a butadiene-styrene random copolymer, the amount of block styrene is 10% by mass or more based on the total amount of the modified butadiene-based polymer by the Kolthoff method. Preferably, it is 13 mass% or more.

  The modified butadiene polymer of the present embodiment may be one that has been oil-extended with an extending oil. As the extender oil, aroma oil, naphthenic oil, paraffin oil, and an aroma substitute oil containing 3% by mass or less of a polycyclic aromatic component by IP346 method are preferable. In particular, it is more preferable to use an aroma substitute oil having a polycyclic aromatic component of 3% by mass or less from the viewpoints of environmental safety, prevention of oil bleeding, and wet grip characteristics. As an aroma substitute oil, TDAE (Treated Distillate Aromatic Extracts / Treatment Distillate Aromatic Extract), MES (Mild Extract Solvent Extract) In addition, there are SRAE (Special Residual Aromatic Extracts / aromatic special extract), RAE (Residual Aromatic Extracts / residual aromatic extract) and the like.

  The amount of the extender oil used is arbitrary, but it is preferably 5 to 60 parts by mass and more preferably 20 to 50 parts by mass with respect to 100 parts by mass of the modified butadiene polymer.

  The modified butadiene polymer of the present embodiment is preferably a polymer or an oil-extended polymer thereof having a Mooney viscosity of 30 to 100 at 100 ° C. If it is this range, workability is good and the dispersibility of a filler is favorable, and this embodiment can be implemented suitably.

[Method for producing modified butadiene-based polymer (first embodiment)]
The method for producing the modified butadiene polymer of the present embodiment uses an alkali metal compound or alkaline earth metal compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group as a polymerization initiator. 1,3-butadiene is polymerized, or 1,3-butadiene and a monomer copolymerizable with the 1,3-butadiene are copolymerized to start polymerization having an active terminal and the functional group A polymerization step for obtaining a butadiene-based polymer having a terminal;
A compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group at the active terminal of the butadiene-based polymer, or at least selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group A terminal modification step of reacting a compound that forms one type of functional group to introduce the functional group;
A silicon compound having at least one functional group selected from the group consisting of a vinyl group in the main chain of the butadiene-based polymer and an amino group, an alkoxysilyl group, or a hydroxyl group, or an amino group, an alkoxysilyl group, or a hydroxyl group A main chain modification step of modifying the main chain by hydrosilylation reaction with a silicon compound forming at least one functional group selected from the group.

[Polymerization process using polymerization initiator]
In the polymerization step of this embodiment, an alkali metal compound or alkaline earth metal compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group is used as a polymerization initiator, and 1,3- A butadiene-based polymer having an active terminal and a polymerization initiating terminal having the above functional group by polymerizing butadiene or copolymerizing 1,3-butadiene and a monomer copolymerizable with 1,3-butadiene. This is a process for obtaining a coalescence.

(Polymerization initiator)
The polymerization initiator is not particularly limited as long as it is an alkali metal compound or an alkaline earth metal compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group. Among these, an alkali metal compound having an amino group is preferable.

  Although the alkali metal compound used as a polymerization initiator is not particularly limited, for example, an organic lithium compound is preferable. The organic lithium compound may be either a low molecular weight organic lithium compound or a solubilized oligomeric organic lithium compound. Examples thereof 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 lithium. When an organolithium compound is used, the initiation efficiency is good and the living rate of the polymer is good. Although it does not restrict | limit especially as an organic lithium compound, For example, an organic monolithium compound, an organic dilithium compound, and an organic polylithium compound are mentioned. As the organic group, a hydrocarbon containing a functional group is preferable. In this case, there is an advantage that the solubility in an organic solvent is excellent, and the start speed is also excellent. Further, by using a compound having a nitrogen-lithium bond or a compound having a tin-lithium bond, a modifying group containing a functional group can be imparted to the start terminal.

  Although it does not specifically limit as another organic alkali metal compound of an organic lithium compound, For example, an organic sodium compound, an organic potassium compound, an organic rubidium compound, an organic cesium compound etc. are mentioned. More specifically, sodium naphthalene, potassium naphthalene, etc. are mentioned. In addition, alkoxides such as lithium, sodium, and potassium, sulfonates, carbonates, amides, and the like can be given. Moreover, you may use together with another organometallic compound.

  Examples of the alkaline earth metal compound used as the polymerization initiator include organic magnesium compounds, organic calcium compounds, and organic strontium compounds. Further, alkaline earth metal alkoxides, sulfonates, carbonates, amides and other compounds may be used. These organic alkaline earth metal compounds may be used in combination with the alkali metal compound or other organic metal compounds.

  The alkali metal compound having a functional group that can be used as a polymerization initiator is not particularly limited. For example, a lithium amide compound obtained by lithiation of hydrogen of a secondary amine, or the functional group bonded thereto. Examples include alkyl lithium. By these, a functional group can be imparted to the polymerization initiation terminal of the butadiene-based polymer. Although it does not specifically limit as a functional group, A functional group inactive with respect to an alkali metal is preferable, for example, a disubstituted amino group, ie, a tertiary amine, a protected monosubstituted amino group, and a protected amino group are preferable. . Examples of the protected monosubstituted amino group or the protected amino group include those obtained by substituting one hydrogen of the monosubstituted amino group or two hydrogens of the amino group with a trialkylsilyl group, respectively. .

  Although it does not specifically limit as a polymerization initiator which has a functional group, Specifically, the compound shown below is mentioned. In addition, the kind of functional group which can be provided to a polymer is described in parentheses. For example, dipropylaminolithium, diisopropylaminolithium, dibutylaminolithium, tetramethyleneiminolithium, pentamethyleneiminolithium, hexamethyleneiminolithium, heptamethyleneiminolithium, 2-dimethylaminoethyllithium, 3-dimethylaminopropyllithium, 3 -Diethylaminopropyllithium, 4-dimethylaminobutyllithium (above for 2-substituted amino group), 2-trimethylsilylethylaminoethyllithium, 3-trimethylsilylmethylaminopropyllithium (above for monosubstituted amino group), 2-bistrimethylsilylaminoethyl There are lithium and 3-bistrimethylsilylaminopropyllithium (the above is an amino group).

  Moreover, as a polymerization initiator, the oligomer initiator with which various lithium initiators and the monomer reacted can be used. In that case, the monomer which has at least 1 sort (s) of functional group chosen from the group which consists of an amino group, an alkoxy silyl group, and a hydroxyl group can be used for the monomer. Although it does not specifically limit as an oligomer initiator, 1000 molecular weight or less is preferable because it is industrially easy to handle. In a method in which polymerization or copolymerization is performed using a polymerization initiator having a functional group and a functional group is introduced into the terminal end in the next step, another type of functional group can be selected.

[Method for producing modified butadiene-based polymer (second embodiment)]
Further, in the method for producing the modified butadiene polymer of the present embodiment, a polyfunctional initiator can be used instead of the polymerization initiator. In this case, the modified butadiene polymer is produced by polymerizing 1,3-butadiene using a polyfunctional initiator, or 1,3-butadiene and a monomer copolymerizable with the 1,3-butadiene. And a polymerization step to obtain a butadiene-based polymer having an active end,
A compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group at the active terminal of the butadiene-based polymer, or at least selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group A terminal modification step of reacting a compound that forms one type of functional group to introduce the functional group at two or more ends;
From a vinyl group of the main chain of the butadiene-based polymer, a silicon-modified group having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group, or an amino group, an alkoxysilyl group, or a hydroxyl group A main chain modification step of modifying the main chain by hydrosilylation reaction with a silicon compound that forms at least one functional group selected from the group consisting of:

[Polymerization process using polyfunctional initiator]
The polymerization step in the case of using a polyfunctional initiator is a polymerization of 1,3-butadiene using a polyfunctional initiator, or 1,3-butadiene and a monomer copolymerizable with the 1,3-butadiene. Are copolymerized to obtain a butadiene-based polymer having an active end.

  Thereafter, as a method for introducing functional groups into two or more terminals of the butadiene-based polymer, at least one selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group at two or more active terminals of the butadiene-based polymer. A modification step of introducing two or more functional groups is performed by reacting a compound having a functional group or a compound that forms at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group.

(Multifunctional initiator)
Although it does not specifically limit as a polyfunctional initiator, Specifically, there exist an organic dilithium compound and an organic polylithium compound. Although it does not specifically limit as an organic group, A hydrocarbon is suitable. Thereby, there exists an advantage which is excellent in the solubility to an organic solvent, and also start speed is excellent.

  In addition, the method for preparing the polyfunctional initiator is not particularly limited, and specifically, a method by a reaction of a metal lithium dispersion and a polyhalogenated hydrocarbon compound, a method by a reaction of metal lithium and a diene compound, organic The method by reaction of a monolithium compound and a polyfunctional compound is mentioned. Among these, the thing by reaction of an organic monolithium compound and a polyfunctional compound is preferable. Although it does not specifically limit as a polyfunctional compound, Specifically, it is an aromatic compound, the compound which has two or more double bonds adjacent to an aromatic group, and has two or more active hydrogens which can be substituted by lithium Compounds. When the organic monolithium compound is reacted with these polyfunctional compounds, a conjugated diene compound and an aromatic vinyl compound can be present to form an oligomer. In order to increase the reactivity of the organic monolithium compound, a polar compound such as an ether compound or a tertiary amine compound may be present. The aromatic compound having a plurality of double bonds adjacent to the aromatic group is not particularly limited, and examples thereof include diisopropenylbenzene and divinylbenzene. The compound having a plurality of active hydrogens capable of substituting for lithium is not particularly limited, and examples thereof include 1,3,5-trimethylbenzene.

  The hydrocarbon dilithium compound is not particularly limited. For example, 1,3-bis (1-lithio-1,3-dimethylpentyl) obtained from the reaction of secondary or tertiary butyllithium with diisopropenylbenzene. Benzene, 1,4-bis (1-lithio-1,3-dimethylpentyl) benzene, 1,3-bis (1-lithio-1,3,3-trimethylbutyl) benzene, and 1,4-bis (1 -Lithio-1,3,3-trimethylbutyl) benzene and the like.

  Further, the hydrocarbon polylithium compound is not particularly limited. For example, a reaction product of n-butyllithium, divinylbenzene and 1,3-butadiene, secondary or tertiary butyllithium and 1,3,5-trimethyl. Examples include reaction products with benzene.

  The usage-amount of these polyfunctional initiators is adjusted with the molecular weight of the target butadiene-type polymer, and 0.01-0.2 mass part can be used with respect to 100 mass parts of monomers. Preferably it is 0.02-0.15 mass part. At this time, it is preferable to consider deactivation due to moisture and impurities in the monomer and solvent, chain transfer due to impurities, deactivation due to formation of metal hydride at the polymerization terminal, and the like.

  Hereinafter, the production method of the modified butadiene polymer when the polymerization initiator or the polyfunctional initiator is used will be further described.

  The polymerization or copolymerization of 1,3-butadiene is preferably performed by solution polymerization in an inert solvent. Although it does not specifically limit as a polymerization solvent, For example, hydrocarbon solvents, such as a saturated hydrocarbon and an aromatic hydrocarbon, are mentioned. Specifically, 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; Examples thereof include hydrocarbons composed of a mixture thereof. Preferably, they are hexane and cyclohexane. The hexane may be mixed hexane obtained as a hexane fraction in petroleum refining. Cyclohexane may be a mixture of 10 to 20% by mass of hexane for the purpose of lowering the freezing point.

  Before being subjected to a polymerization reaction, it is preferable to treat moisture, allenes, acetylenes, aldehydes and the like, which are impurities in the monomer and the polymerization solvent, with an organometallic compound. Thereby, a butadiene-based polymer having a high concentration of active terminals is obtained, and further, a high modification rate is achieved in the terminal modification step and the main chain modification step, which is preferable.

  Further, a polar compound may be added in the polymerization or copolymerization of 1,3-butadiene. By adding a polar compound, the vinyl aromatic compound can be randomly copolymerized with a conjugated diene compound such as 1,3-butadiene. The polar compound can also be used as a vinylating agent for controlling the microstructure of the conjugated diene moiety. It is also effective in promoting the polymerization reaction.

  Such a polar compound is not particularly limited. For example, tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, 2-ethoxymethyltetrahydrofuran, 2,2 Ethers such as bis (2-oxolanyl) propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, quinuclidine; bis (2-dimethylaminoethyl) ether, 2- Tertiary amine-containing ether compounds such as dimethylaminoethyl-2-ethoxyethyl ether; potassium tert-amylate, potassium ert- butylate, sodium -tert- butylate, alkali metal alkoxide compounds such as sodium Ami methoxide; can be used phosphine compounds such as triphenylphosphine. These polar compounds may be used alone or in combination of two or more.

  The usage-amount of a polar compound is not specifically limited, It can select according to the objective etc. Usually, it is preferable that it is 0.01-100 mol with respect to 1 mol of a polymerization initiator or a polyfunctional initiator. Such a polar compound can be used in an appropriate amount as a regulator of the microstructure of the polymer conjugated diene moiety, depending on the desired amount of vinyl bonds. Many polar compounds simultaneously have an effective randomizing effect in the copolymerization of a conjugated diene compound and an aromatic vinyl compound, and can be used as an adjustment of the distribution of the aromatic vinyl compound and an adjuster of the styrene block amount. As a method for randomizing the conjugated diene compound and the aromatic vinyl compound, for example, as described in JP-A-59-140221, the total amount of styrene and a part of 1,3-butadiene may be used together. A method may be used in which a polymerization reaction is started and the remaining 1,3-butadiene is added continuously or intermittently during the copolymerization reaction.

  The polymerization temperature when copolymerizing 1,3-butadiene or 1,3-butadiene and another copolymerizable monomer is not particularly limited as long as living anion polymerization proceeds, but productivity is not limited. In view of the above, it is preferably 0 ° C. or higher, and a compound having at least one functional group selected from the group consisting of a mino group, an alkoxysilyl group, and a hydroxyl group with respect to the active terminal after polymerization, an amino group, an alkoxy group From the viewpoint of sufficiently securing the reaction amount of the compound that forms at least one functional group selected from the group consisting of a silyl group and a hydroxyl group, the temperature is preferably 120 ° C. or lower. More preferably, it is 50-100 degreeC.

  Moreover, when copolymerizing 1,3-butadiene or 1,3-butadiene and another copolymerizable monomer, in order to control branching from the viewpoint of preventing cold flow of the conjugated diene polymer. Polyfunctional aromatic vinyl compounds such as divinylbenzene may also be used.

  Although it does not specifically limit as a polymerization mode at the time of copolymerizing 1,3-butadiene or 1,3-butadiene and another copolymerizable monomer, it is a batch type (also referred to as “batch type”). The polymerization can be carried out in a continuous manner. In the continuous mode, one or two or more connected reactors can be used. As the reactor, a tank type with a stirrer, a tube type or the like is used. In the batch system, the molecular weight distribution of the obtained polymer is generally narrow, and Mw / Mn tends to be 1.0 or more and less than 1.8. In the continuous system, the molecular weight distribution is generally wide, and Mw / Mn tends to be 1.8 or more and 3 or less.

(Terminal denaturation step)
The terminal modification step includes a compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group at the active end of the butadiene-based copolymer, or an amino group, an alkoxysilyl group, and a hydroxyl group. It is a step of introducing a functional group by reacting a compound that forms at least one functional group selected from the group (hereinafter also referred to as “modifier”). This step is the same both when a polymerization initiator is used and when the polyfunctional initiator is used.

(Modifier)
In the terminal modification step, the active terminal of the butadiene-based copolymer is reacted with a modified compound having at least one functional group selected from an amino group, an alkoxysilyl group and a hydroxyl group to form a bond, or these This is a step of reacting a compound that forms a functional group to modify the terminal end. In the modifier used in this step, the functional group bonded to the active terminal of the butadiene polymer is not particularly limited, but specifically, a halogen group, a double bond, a ketone group, an ester group, an amide group, an epoxy group Group, alkoxysilyl group and the like.

  Among the modifiers, the compound having an amino group is not particularly limited. Specifically, the compound has a functional group bonded to the amino group and the polymer active terminal in the molecule, and preferably has no active hydrogen. Is mentioned. The amino group is not particularly limited, but specifically, a functional group inert to an alkali metal is preferable, and a disubstituted amino group, that is, a tertiary amine, a protected monosubstituted amino group, two hydrogens. Is preferably an amino group protected. Examples of protected mono-substituted amino groups or amino groups in which two hydrogens are protected include substitution of one hydrogen of a mono-substituted amino group or two hydrogens of an amino group with a trialkylsilyl group, respectively. The thing which was done is mentioned.

  Among the modifiers, the compound having an alkoxysilyl group is not particularly limited. Specifically, the compound has a plurality of alkoxysilyl groups in the molecule (this includes a silyl group having a plurality of alkoxy groups bonded thereto). And a compound having a functional group bonded to an alkoxysilyl group and a polymer active terminal in the molecule. In addition, it is preferable that these are compounds which do not have active hydrogen.

  Among the modifiers, the compound that forms a hydroxyl group is not particularly limited, and specifically, a compound having a functional group that binds to the active terminal of the polymer and that has a functional group that generates a hydroxyl group after the coupling reaction, a heavy compound. A compound having a functional group that is not bonded to the coalesced active end and that has a functional group that is subsequently generated by a reaction such as hydrolysis is preferable, and a compound having no active hydrogen is preferable.

  Examples of the compound having a functional group that generates a hydroxyl group after the coupling reaction include compounds having a ketone group, an ester group, an amide group, an epoxy group, and the like. Examples of the compound having a functional group that generates a hydroxyl group by a reaction such as hydrolysis after the binding reaction include compounds having an alkoxysilyl group, an aminosilyl group, and the like.

  Examples of specific compounds of the modifier are shown below. Although it does not specifically limit as a compound which couple | bonds with a polymer active terminal and forms an amino group at the terminal of a polymer, C = N double bond compounds, such as N, N'-dicyclohexylcarbodiimide, are illustrated.

  Although it does not specifically limit as a compound which couple | bonds with a polymer active terminal and forms an amino group and a hydroxyl group at the terminal of a polymer, N, N, N ', N'-tetramethyl-4,4'-diaminobenzophenone ( Michler's ketone), ketone compounds having amino groups such as N, N, N ′, N′-tetraethyl-4,4′-diaminobenzophenone; cyclic urea compounds such as N, N′-dimethylimidazolidinone and N-methylpyrrolidone A cyclic amide, that is, a lactam compound; an amino group-containing epoxy compound such as N, N, N ′, N′-tetraglycidyl-1,3-bisaminomethylcyclohexane; a nitrogen-containing heterocyclic compound described in JP-A-2001-131227; Examples thereof include an epoxy compound having a group.

  The compound that forms an alkoxysilyl group at the polymer terminal by binding to the polymer active terminal is not particularly limited, but is a halogenated alkoxysilane compound such as trimethoxychlorosilane, triethoxychlorosilane, diphenoxydicrylolosilane, etc. And polyfunctional alkoxysilane compounds such as bis (trimethoxysilyl) ethane and bis (3-triethoxysilylpropyl) ethane.

  The compound that forms an alkoxysilyl group and a hydroxyl group at the polymer terminal by binding to the polymer active terminal is not particularly limited, but 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane epoxy Examples thereof include polysiloxane compounds having a group and an alkoxysilyl group in the molecule.

  Although it does not specifically limit as a compound which couple | bonds with a polymer active terminal and forms an amino group and an alkoxysilyl group at the terminal of a polymer, 3-dimethylaminopropyl trimethoxysilane, 3-dimethylaminopropyl dimethoxymethylsilane, 3 An alkoxysilane compound to which an alkyl group having an amino substituent such as dimethylaminopropyltriethoxysilane, bis (3-trimethoxysilylpropyl) methylamine, bis (3-triethoxysilylpropyl) methylamine is bonded; N- [ WO 2007 / such as 3- (triethoxysilyl) -propyl] -N, N′-diethyl-N′-trimethylsilyl-ethane-1,2-diamine, 3- (4-trimethylsilyl-1-piperazinyl) propyltriethoxysilane Protected device according to 034785 Alkoxysilane compound having an amino group bonded thereto; N- [2- (trimethoxysilanyl) -ethyl] -N, N ′, N′-trimethylethane-1,2-diamine, 1- [3- (triethoxysila Nyl) -propyl] -4-methylpiperazine, 2- (trimethoxysilanyl) -1,3-dimethylimidazolidine, bis- (3-dimethylaminopropyl) -dimethoxysilane, and the like described in WO 2008/013090 An alkoxysilane compound to which a substituted amino group is bonded; 1,4-bis [3- (trimethoxysilyl) propyl] piperazine, 1,4-bis [3- (triethoxysilyl) propyl] piperazine, and the like described in WO2011 / 040313 An alkoxysilane compound to which a nitrogen-containing heterocyclic ring is bonded; 3- [N, N-bis (trimethylsilyl) amino ] Propyltrimethoxysilane, 3- [N, N-bis (trimethylsilyl) amino] propylmethyldiethoxysilane, 2,2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclo Examples include alkoxysilane compounds to which an azasilane group described in WO2011 / 129425, such as pentane and 2,2-diethoxy-1- (3-triethoxysilylpropyl) -1-aza-2-silacyclopentane, are bonded.

  Although it does not specifically limit as a compound couple | bonded with a polymer active terminal and forms a hydroxyl group at the terminal of a polymer, Epoxy compounds, such as ethylene oxide and a propylene oxide; Ketone compounds, such as a benzophenone, etc. are illustrated.

  The reaction temperature, reaction time, and the like when the above-described compound is reacted with the polymer active terminal are not particularly limited, but are preferably reacted at 0 to 120 ° C. for 30 seconds or longer.

  Although the addition amount of the modifier described above is not particularly limited, the total number of moles of the modifier is 0.1 to 6 times the number of moles of the polymerization initiator or polyfunctional initiator, that is, the number of polymer molecules. The range is preferably 0.2 to 3 times, more preferably 0.5 to 2 times. If the addition amount is 0.5 times or more, it is preferable from the viewpoint of obtaining a sufficient modification rate in the target modified butadiene-based polymer. Further, for improving processability, polymer terminals can be coupled to form a branched polymer component. In that case, a polyfunctional compound can be used as a modifier. The addition amount of such a polyfunctional modifier is preferably 0.5 times or less with respect to the number of moles of the polymerization initiator or polyfunctional initiator, that is, the number of polymer molecules.

  Further, for the purpose of preventing side reactions in which the functional groups are bonded to each other and for the purpose of improving the affinity with different types of fillers, the terminal functional group can be changed to two or more different functional groups.

  When the polymerization step is a batch type, the terminal modification step may be carried out continuously in the reactor used in the polymerization step or transferred to the next reactor. When the polymerization step is continuous, the polymerization step is carried to the next reactor. The terminal modification step is preferably carried out immediately after the polymerization step, and the reaction is preferably carried out by mixing the modifier within 5 minutes. The reactor for the denaturing reaction is preferably one that is sufficiently stirred. Specifically, there are a static mixer type reactor, a vertical reactor with a stirrer and the like.

[Main chain modification step]
The main chain modification step is a silicon compound having at least one functional group selected from the group consisting of a vinyl group of the main chain of the butadiene-based polymer having a modified terminal and an amino group, an alkoxysilyl group, and a hydroxyl group, Alternatively, the main chain is modified by hydrosilylation reaction with a silicon compound forming at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group. This step is the same both when a polymerization initiator is used and when the polyfunctional initiator is used.

  The hydrosilylation reaction can be carried out in a kneader in an organic solvent solution or as a polymer (without solvent). Specifically, the vinyl group of the main chain of the butadiene polymer can be modified by reacting a silicon compound such as a hydrosilane compound having a functional group in the presence of a catalyst. After the polymerization step in the solution polymerization, it is preferable to use the polymer solution obtained by modifying the terminal portion of the polymer as described above as it is.

(Silicon compound)
The silicon compound into which the silicon-modified group having a functional group is introduced is not particularly limited, and specific examples include a hydrosilane compound. Such a hydrosilane compound is not particularly limited, and specifically, any hydrosilane compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, and a hydroxyl group may be used. Among them, the general formula HSiR ″ _3-n X _n , (R ″ is not particularly limited, but represents a hydrocarbon group having 1 to 20 carbon atoms, X is an amino group, an alkoxy group, a hydroxyl group or an amino group. Represents a hydrocarbon or organosilane compound group having at least one functional group selected from the group consisting of a group, an alkoxysilyl group, and a hydroxyl group, and n is 1 to 3). More preferably, n is 1, and preferably R ″ represents a hydrocarbon having 1 to 3 carbon atoms. When the hydrosilane compound has such a configuration, the yield of the hydrosilylation reaction is high.

  Moreover, as a silicon compound which introduce | transduces the silicon modified group which has a functional group, at least 1 sort (s) of functional group chosen from the group which consists of an amino group, an alkoxy silyl group, or a hydroxyl group by hydrolyzing after a hydrosilation reaction etc. It may be a silicon compound that forms a group. Such a silicon compound is not particularly limited, and specifically, a functional group that forms at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group, or a hydroxyl group by performing hydrolysis or the like. Mention may be made of hydrosilane compounds having a group. More specifically, hydrosilane compounds having a protected monosubstituted amino group, a protected disubstituted amino group, a protected hydroxyl group, and the like can be given.

  The silicon compound having an alkoxy group is not particularly limited, and specific examples thereof include dimethylmonomethoxysilane, dimethylmonoethoxysilane, dimethylmonopropoxysilane, dimethylmonobutoxysilane, methyldimethoxysilane, methyldiethoxysilane, methyldioxysilane. Examples include propoxysilane, ethyldiethoxysilane, trimethoxysilane, triethoxysilane, and the like, and organosiloxane compounds having an H-Si group and an alkoxysilyl group in the molecule.

  Although it does not specifically limit as a silicon compound which has a 2-substituted amino group, Specifically, dimethylaminodimethylsilane, diethylaminodimethylsilane, diethylaminodiethylsilane, 3-diethylaminopropyldimethylsilane, 4-dimethylaminobutyldimethylsilane, 6 -Diethylaminohexyldimethylsilane.

  The silicon compound having a protected monosubstituted amino group is not particularly limited, and specific examples include N-methyl-N-trimethylsilylaminodimethylsilane and N-ethyl-N-trimethylsilylaminodiethylsilane.

  The silicon compound having a protected disubstituted amino group is not particularly limited, and specific examples include N, N-bistrimethylsilylaminodimethylsilane and N, N-bistrimethylsilylaminodiethylsilane.

  The silicon compound having a hydroxyl group is not particularly limited, and specific examples include dimethylhydroxysilane, diethylhydroxysilane, and dibutylhydroxysilane.

  Although it does not specifically limit as a silicon compound which forms a hydroxyl group by hydrolysis, Specifically, alkoxysilane compounds, such as dimethylmonomethoxysilane, dimethylmonoethoxysilane, methyldimethoxysilane, trimethoxysilane, triethoxysilane; Examples include silane compounds having an epoxy group such as glycidylsilane and diethylglycidylsilane.

  When the vinyl group of the main chain of the terminal-modified butadiene polymer is modified, the amount of the hydrosilane compound to react is arbitrary depending on the purpose, but is preferably 1 with respect to 1 mol of the main chain of the butadiene polymer. -10 mol. By modifying 1 to 10 moles with respect to 1 mole of the main chain, as described later, when a modified butadiene polymer and silica are mixed to obtain a rubber composition, good affinity is obtained, Excellent workability. More preferably, it is 2 to 5 moles per mole of the main chain.

When performing the hydrosilylation reaction, a predetermined catalyst may be used. Although it does not restrict | limit especially as a catalyst, For example, platinum or a platinum containing catalyst is mainly used. Preferably, a homogeneous platinum catalyst is suitably used, for example, chloroplatinic acid solution (ie, Speier catalyst), Pt ₂ (divinyltetramethyldisiloxane) ₃ solution (ie, Karstedt catalyst), dichloro (η ⁴ -cyclo-1 , 5-diene) Pt (II) and the like. The amount of platinum catalyst used for the reaction is preferably 0.01 to 10 mmol / mol, more preferably 0.1 to 1 mmol / mol per hydrosilane compound.

  In addition, examples of the catalyst used for the hydrosilylation reaction include metallocene compounds containing any of Ti, Zr, Hf, Ni, Co, Ru, and Rh, and in particular, titanocene compounds and organolithium or organoaluminum. The reaction product is preferred.

  The hydrosilylation reaction is preferably performed in the range of 20 to 150 ° C, more preferably in the range of 50 to 120 ° C. Within this range, the reaction can be carried out with an appropriate reaction time, and there are few side reactions such as gelation, which is practical. In addition, when using a polymerization solution as it is and performing hydrosilylation reaction following terminal modification reaction, it can carry out at the same temperature as polymerization temperature. In the solution state, the reaction time is preferably 10 minutes to 5 hours, more preferably 30 minutes to 2 hours.

[Post-processing]
As described above, when the modified butadiene-based polymer having undergone terminal modification and main chain modification is obtained as a solution, an antioxidant and additives are added as necessary, and then the solvent is removed by a conventional method. Removal and drying can be performed. Thereby, it can be set as the raw material of the rubber composition mentioned later. Specifically, a steam stripping and dehydration drying method, a drum dryer, a flushing and a direct desorption method using a vent extruder are used.

  It does not specifically limit as antioxidant, A well-known thing can be used. For example, 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3- (4′-hydroxy-3 ′, 5′-di-tert-butylphenol) propionate, 2-methyl-4 Antioxidants such as 1,6-bis [(octylthio) methyl] phenol are preferred.

  If necessary, as an additive, alcohol such as water, methanol, ethanol, isopropanol, stearic acid, oleic acid, myristic acid, lauric acid, decane can be added to remove or neutralize ionic substances. A carboxylic acid such as acid, citric acid or malic acid, an inorganic acid aqueous solution, carbon dioxide gas or the like may be added.

(Rubber composition)
The rubber composition of this embodiment contains 100 parts by mass of raw rubber containing 20 parts by mass or more of the modified butadiene polymer and 5 to 200 parts by mass of filler.

[Raw material]
The content of the modified butadiene polymer in 100 parts by mass of the raw rubber is 20 parts by mass or more, preferably 40 parts by mass or more, more preferably 50 parts by mass or more, and further preferably 60 parts by mass or more. When the amount is 20 parts by mass or more, the filler dispersibility targeted by the present invention is excellent. When the rubber composition of the present embodiment is a vulcanized composition, the properties such as tensile properties and viscoelastic properties are excellent. When used as a material, excellent tire fuel consumption performance, grip performance, wear resistance, and rigidity can be obtained. Further, the content of the modified butadiene polymer is preferably 90 parts by mass or less, more preferably 80 parts by mass or less. By setting it as 90 mass parts or less, the Mooney viscosity of the unvulcanized rubber composition of this embodiment is lowered and workability is improved.

  The raw rubber other than the modified butadiene-based polymer is not particularly limited. For example, a conjugated diene polymer or a hydrogenated product thereof, a random copolymer of a conjugated diene compound and a vinyl aromatic compound, or a hydrogenated product thereof. And a block copolymer of a conjugated diene compound and a vinyl aromatic compound or a hydrogenated product thereof, other conjugated diene copolymer or a hydrogenated product thereof, a non-diene polymer, and natural rubber.

  Specific examples of the conjugated diene polymer or a hydrogenated product thereof are not particularly limited, and examples thereof include butadiene rubber or a hydrogenated product thereof, isoprene rubber or a hydrogenated product thereof.

  Specific examples of the random copolymer of the conjugated diene compound and the vinyl aromatic compound or the hydrogenated product thereof are not particularly limited, and examples thereof include styrene-butadiene copolymer rubber and the hydrogenated product thereof.

  Specific examples of the block copolymer of a conjugated diene compound and a vinyl aromatic compound or a hydrogenated product thereof are not particularly limited, and examples thereof include a styrene-butadiene block copolymer or a hydrogenated product thereof, and a styrene-isoprene block. Examples thereof include styrene elastomers such as copolymers or hydrogenated products thereof.

  Specific examples of the other conjugated diene copolymer or hydrogenated product thereof are not particularly limited, and examples thereof include acrylonitrile-butadiene rubber or a hydrogenated product thereof.

  Further, the non-diene polymer is not particularly limited, and examples thereof include olefin elastomers 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, fluoro rubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α, β-unsaturated nitrile-acrylic ester-conjugated diene copolymer rubber, urethane rubber, polysulfide rubber, etc. Can be mentioned.

  In the present embodiment, when the modified butadiene-based polymer is a modified styrene-butadiene rubber, polybutadiene is preferable as the other rubber. When the modified butadiene polymer is modified polybutadiene, the other rubber is preferably natural rubber or polyisoprene rubber.

  The weight average molecular weight of the various rubber-like polymers described above is preferably 2,000 to 2,000,000, and 5,000 to 1,500,000, from the viewpoint of balance between performance and processing characteristics. Is more preferable. Also, so-called liquid rubber having a low molecular weight can be used. These rubber-like polymers may be used individually by 1 type, and may use 2 or more types together. The weight average molecular weight here is a polystyrene equivalent weight average molecular weight (Mw) obtained by gel permeation chromatography (GPC) measurement.

  The amount of filler used relative to the raw rubber is adjusted such that when a large amount of filler is used, the hardness and modulus increase and the desired physical properties are obtained according to the application. Within this range, the filler is well dispersed and processability is good. For tire applications, the filler is preferably 5 to 150 parts by mass, and for footwear applications, it is preferably 30 to 200 parts by mass. In the range of this embodiment, it can respond widely from a soft thing to a hard thing.

[Filler]
The filler is not particularly limited, and is preferably selected from, for example, silica and carbon rack. In particular, silica is preferably 30 to 100% of the filler, more preferably 40 to 95%, and still more preferably 45 to 90%.

  The silica is not particularly limited, and examples thereof include precipitated silica and fumed silica, and precipitated silica is particularly preferably used.

  In this embodiment, other fillers can be used in combination. Due to the combination effect of various functional groups of the polymer of the present embodiment, both silica and other fillers are well dispersed, and an excellent reinforcing effect is obtained.

As the silica used in the present embodiment, silica having a BET specific surface area of 50 to 500 m ² / g is used. By blending such silica, excellent fuel efficiency, wear resistance, wet skid performance and steering stability can be obtained.

  In the composition containing the functional group-modified butadiene-based polymer of the present embodiment, since the dispersibility of the silica is good, it is possible to use a high specific surface area silica, that is, a fine particle size silica. .

The rubber composition of the present embodiment can contain silica having a CTAB specific surface area of 180 m ² / g or more and a BET specific surface area of 185 m ² / g or more as the fine particle size silica. By blending such a fine particle size silica, excellent low fuel consumption, wear resistance, wet skid performance and steering stability can be obtained in the rubber composition of the present embodiment.

The CTAB (cetyltrimethylammonium bromide) specific surface area of the fine particle size silica contained in the rubber composition of the present embodiment is not particularly limited and is preferably 190 m ² / g or more, more preferably 195 m ² / g or more, Preferably it is 197 m ² / g or more. When the CTAB specific surface area is 180 m ² / g or more, a rubber composition having excellent wear resistance can be obtained. The CTAB specific surface area is not particularly limited, and is preferably 500 m ² / g or less, more preferably 300 m ² / g or less, and further preferably 250 m ² / g or less. When the CTAB specific surface area is 500 m ² / g or less, a rubber composition having excellent processability can be obtained. More preferably, the CTAB specific surface area is 190 to 300 m ² / g. The CTAB specific surface area is measured according to ASTM D3765-92.

The BET specific surface area of the fine particle size silica is not particularly limited, and is preferably 190 m ² / g or more, more preferably 195 m ² / g or more, and further preferably 210 m ² / g or more. When the BET specific surface area is 185 m ² / g or more, a rubber composition having excellent wear resistance can be obtained. The BET specific surface area is not particularly limited, and is preferably 500 m ² / g or less, more preferably 300 m ² / g or less, and still more preferably 260 m ² / g or less. When the BET specific surface area is 500 m ² / g or less, a rubber composition having excellent processability can be obtained. In addition, the BET specific surface area of a silica is measured according to ASTM D3037-81.

  The aggregate size of the fine particle size silica is not particularly limited and can be 30 nm or more, preferably 35 nm or more, more preferably 40 nm or more, still more preferably 45 nm or more, still more preferably 50 nm or more, and even more preferably. Is 55 nm or more. The aggregate size is not particularly limited, and is preferably 100 nm or less, more preferably 80 nm or less, still more preferably 70 nm or less, and particularly preferably 65 nm or less. By having such an aggregate size, it is possible to provide excellent reinforcement, low fuel consumption, wear resistance, wet skid performance and steering stability while having good dispersibility. The aggregate size is also called the aggregate diameter or the maximum frequency Stokes equivalent diameter, and is the particle diameter when a silica aggregate composed of a plurality of primary particles is regarded as one particle. It is equivalent. The aggregate size can be measured using a disk centrifugal sedimentation type particle size distribution measuring device such as BI-XDC (manufactured by Brookhaven Instruments Corporation). Specifically, it can be measured by the method described in JP2011-132307A.

  The average primary particle size of the fine particle size silica is not particularly limited and is preferably 25 nm or less, more preferably 22 nm or less, still more preferably 17 nm or less, and particularly preferably 14 nm or less. The lower limit of the average primary particle size is not particularly limited, but is preferably 3 nm or more, more preferably 5 nm or more, and further preferably 7 nm or more. Within this range, the dispersibility and the reinforcing properties are excellent. The average primary particle size of the fine particle size silica can be determined by observing with a transmission or scanning electron microscope, measuring 400 or more primary particles of silica observed in the visual field, and calculating the average.

  The blending amount of the fine particle silica in the rubber composition of the present embodiment is not particularly limited, and is preferably 5 parts by mass or more, more preferably 15 parts by mass or more, further preferably 100 parts by mass of the rubber component. Is 20 parts by mass or more, more preferably 25 parts by mass or more, and still more preferably 30 parts by mass or more. If it is 5 parts by mass or more, the effect of blending the fine particle silica is sufficiently obtained. The compounding amount of the fine particle size silica is 200 parts by mass or less, preferably 100 parts by mass or less, more preferably 80 parts by mass or less, still more preferably 60 parts by mass or less, and even more preferably 55 parts by mass or less. If it is 200 parts by mass or less, substantially good workability can be obtained.

The rubber composition of the present embodiment is preferably the above rubber composition further containing 5 to 100 parts by mass of silica or carbon black having a BET specific surface area of less than 185 m ² / g as a filler.

In the present embodiment, silica having a BET nitrogen adsorption specific surface area (N ₂ SA) of less than 185 m ² / g is preferably used as the filler, more preferably silica of less than 150 m ² / g, preferably 50 m. ² / g or more is used. Within this range, the balance between reinforcement and dispersibility is good. Moreover, the thing of a suitable particle size is used according to a use.

As carbon black, there are N110, N220, N330, N339, N550, N660, etc. according to the classification of carbon black for rubber according to ASTM, and it is selected according to the application. When carbon black is used in combination, the reinforcing property can be enhanced and the dry grip performance can be improved when used in tire tread applications. Carbon black having a BET nitrogen adsorption specific surface area (N ₂ SA) of preferably less than 185 m ² / g is used, preferably 30 m ² / g or more, more preferably in the range of 50 to 130 m ² / g. It is. Within this range, the balance between reinforcement and dispersibility is good. More preferably N220, N330 and N339 when used for tire tread applications.

(Other fillers)
Furthermore, in the rubber composition of this embodiment, other fillers can be used in addition to the silica described above. Other fillers are not particularly limited, and examples thereof include aluminas, calcium carbonate, clay, magnesium oxide, magnesium hydroxide, talc, titanium oxide, and mica.

(Silane coupling agent)
In the rubber composition of this embodiment, a silane coupling agent may be used. Although it does not restrict | limit especially as a silane coupling agent, For example, it is a compound which has both a silica affinity part and a polymer affinity part in a molecule | numerator, A silica affinity part is typically an alkoxy silyl group, and a polymer affinity part And polysulfide, mercapto group, ethylene double bond, and the like. For example, bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3 -Mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide and the like are used. The compounding quantity of a silane coupling agent is 1-20 mass parts with respect to 100 mass parts of silica, Preferably it is 2-15 mass parts. When the silane coupling agent is blended in this range, the dispersibility of the silica is further improved, the workability is improved, and the performance of the vulcanized rubber is improved such that the wear resistance is improved.

(Plasticizer)
In the rubber composition of this embodiment, the hardness and modulus can be adjusted by using a plasticizer. Although it does not restrict | limit especially as a plasticizer, For example, oil similar to said extending | stretching oil can be used, In addition, various natural product oil, synthetic oil, a low molecular weight polymer, etc. can be used. Also, known processing aids can be used.

(Crosslinking agent)
The rubber composition of the present embodiment may be a rubber composition that is further subjected to a crosslinking treatment by adding a crosslinking agent, a compounding agent, and the like. Such a crosslinking agent is not particularly limited, and for example, a sulfur vulcanizing agent, an organic peroxide, or the like is used.

  Although it does not restrict | limit especially as a sulfur type vulcanizing agent, For example, sulfur, morpholine disulfide etc. are used, As an organic peroxide, for example, benzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-Butyl cumyl peroxide, cumene hydroperoxide and the like are used.

  Further, if necessary, a vulcanization accelerator may be blended, and the vulcanization accelerator is not particularly limited. For example, sulfenamide, thiazole, thiuram, thiourea, guanidine, dithiocarbamic acid It is possible to use one containing at least one of a system, an aldehyde-amine system, an aldehyde-ammonia system, an imidazoline system, or a xanthate vulcanization accelerator.

  Furthermore, if necessary, a vulcanization aid may be blended, and the vulcanization aid is not particularly limited, but for example, zinc oxide, stearic acid and the like can be used. Furthermore, an anti-aging agent can be used.

(Method for producing rubber composition)
The rubber composition of the present embodiment is a method of mixing and mechanically mixing the above-described raw rubber, silica, and other fillers, cross-linking agents, various additives, plasticizers, etc., as necessary, solution, dispersion state It can be manufactured by applying a method such as mixing in In particular, a method of mechanically kneading with a kneader is preferable, and for example, a known method such as a roll mill, a Banbury mixer, a kneader, or a Brabender is possible.

〔tire〕
The rubber composition of this embodiment can be made into a tire by vulcanization molding according to a conventional method. As vulcanized rubber, it is used for tires, anti-vibration rubber, and various industrial products. In particular, it is used as a rubber for a tire tread, and SBR is particularly preferably used for a cap tread.

  Hereinafter, although a specific Example and a comparative example are given and demonstrated, this invention is not limited to these.

  First, measurement methods and evaluation methods of physical properties applied to Examples and Comparative Examples are shown below.

[(1) Bonded styrene content]
The sample for measurement is a chloroform solution, and UV-2450 manufactured by Shimadzu Corporation is used as a measuring instrument to measure the amount of ultraviolet (UV) absorption at a wavelength of 254 nm by the phenyl group of styrene, and the amount of bound styrene (% by mass) is calculated. It was measured.

[(2) Microstructure of butadiene moiety (1,2-vinyl bond amount)]
A sample for measurement is a carbon disulfide solution, a solution cell is prepared, and an infrared spectrum is measured in a range of 600 to 1000 cm ⁻¹ using JASCO Corporation FT-IR230 as a measuring instrument, The microstructure (1,2-vinyl bond amount) of the butadiene portion was determined from the absorbance at a predetermined wave number according to the calculation formula of the Hampton method.

[(3) Mooney viscosity]
According to JIS K6300-1, using an L-shaped rotor, preheating was performed at 100 ° C. for 1 minute, and the viscosity after 4 minutes was measured. A smaller value indicates a lower viscosity.

[(4) Glass transition temperature (Tg)]
In accordance with ISO 22768: 2006, a DSC curve was recorded using a differential scanning calorimeter DSC3200S manufactured by Mac Science, while increasing the temperature from −100 ° C. to 20 ° C./min under a flow of helium at 50 mL / min. The peak top (Infection point) of the differential curve was taken as the glass transition temperature.

[(5) Molecular weight, molecular weight distribution]
Using a gel permeation chromatography (GPC) measuring device in which three columns each having a polystyrene gel as a filler were connected, a chromatogram was measured, and a weight average molecular weight (Mw) based on a calibration curve using standard polystyrene. ) And number average molecular weight (Mn). Tetrahydrofuran (THF) was used as the eluent. As the column, guard column: TSKguardcolumn HHR-H manufactured by Tosoh Corporation, column: TSKgel G6000HHR, TSKgel G5000HHR, TSKgel G4000HHR manufactured by Tosoh Corporation were used. An RI detector (“HLC8020” manufactured by Tosoh Corporation) was used under the conditions of a column oven temperature of 40 ° C. and a THF flow rate of 1.0 mL / min. 10 mg of a sample for measurement was dissolved in 20 mL of THF to prepare a measurement solution, and 200 μL of the measurement solution was injected into a GPC measurement device and measured.
The molecular weight distribution (Mw / Mn) was calculated from the weight average molecular weight (Mw) and the number average molecular weight (Mn) determined as described above.

[(6) Denaturation rate]
The measurement was performed by applying the property of adsorbing the modified component to the GPC column using silica gel as a filler. As shown below, a sample solution containing a sample and a low molecular weight internal standard polystyrene (molecular weight 5,000) is transferred to the silica column from the difference between the chromatogram measured with the polystyrene gel column and the chromatogram measured with the silica column. The amount of adsorption was measured to determine the modification rate.
・ Sample solution preparation:
A sample solution was prepared by dissolving 10 mg of a sample and 5 mg of standard polystyrene in 20 mL of THF.
-GPC measurement conditions using a polystyrene column:
Using THF as an eluent, 200 μL of the sample solution was injected into the apparatus for measurement. The column used was guard column: TSKguardcolumn HHR-H manufactured by Tosoh Corporation, column: Tosoh TSKgel G6000HHR, TSKgel G5000HHR, TSKgel G4000HHR. A chromatogram was obtained by measurement using a RI detector (HLC8020 manufactured by Tosoh Corporation) under conditions of a column oven temperature of 40 ° C. and a THF flow rate of 1.0 mL / min.
-GPC measurement conditions using a silica column:
Using THF as an eluent, 200 μL of sample was injected into the apparatus for measurement. As the column, guard column: DIOL 4.6 × 12.5 mm 5 micron, column: Zorbax PSM-1000S, PSM-300S, PSM-60S were used. CCP8020 series build-up type GPC system manufactured by Tosoh Corporation with column oven temperature of 40 ° C. and THF flow rate of 0.5 ml / min: AS-8020, SD-8022, CCPS, CO-8020, RI-8021, using RI detector To obtain a chromatogram.
・ Method of calculating denaturation rate:
Sample with 100 as the total peak area of the chromatogram using the polystyrene column, P1 as the peak area of the sample, P2 as the peak area of the standard polystyrene, and 100 as the entire peak area of the chromatogram using the silica column Assuming that the peak area of P3 is P3 and the peak area of standard polystyrene is P4, the modification rate (%) was obtained from the following formula.
Denaturation rate (%) = [1- (P2 × P3) / (P1 × P4)] × 100
(However, P1 + P2 = P3 + P4 = 100)

[(7) Styrene chain]
According to the method of Kolthoff, an osmium acid decomposition product of a sample for measurement was obtained, and this was used to precipitate insoluble polystyrene corresponding to block polystyrene in methanol. The amount of insoluble polystyrene was quantified, and the amount of block styrene was calculated as mass% per butadiene polymer.
In addition, the content of the styrene single chain having one styrene unit and the styrene long chain having 8 or more styrene units connected to the bound styrene content is determined according to the method of Tanaka et al. (Polymer, 22, 1721 (1981)). The styrene-butadiene copolymer rubber was decomposed with ozone and then analyzed by gel permeation chromatography (GPC).

[Example 1]
Using an autoclave with an internal volume of 11 liters and a temperature-controllable autoclave equipped with a stirrer and a jacket as the reactor, 1,3-butadiene 770 g, 260 g of styrene, 4250 g of cyclohexane, 2, 1.30 g of 2-bis (2-oxolanyl) propane was charged into the reactor, and the reactor internal temperature was maintained at 38 ° C. As a polymerization initiator, a cyclohexane solution containing 10.4 mmol of hexamethyleneiminolithium in which 10.4 mmol of hexamethyleneimine and 10.4 mmol of n-butyllithium were reacted in advance was supplied to the reactor. After the start of the polymerization reaction, the temperature inside the reactor started to rise due to the exotherm caused by the polymerization, and the final temperature inside the reactor reached 90 ° C. Two minutes after the peak of the reaction temperature was reached, 0.78 mmol of N, N, N ′, N′-tetraglycidyl-1,3-bisaminomethylcyclohexane was added to the reactor, and after another 5 minutes, N, N, N 7.2 mmol of ', N'-tetramethyl-4,4'-diaminobenzophenone was added and a denaturation reaction was performed for 5 minutes.

  Subsequently, 21 mmol of dimethylmonoethoxysilane and an isopropanol solution of chloroplatinic acid were added. The chloroplatinic acid used was 0.30 mmol / mol with respect to the hydrosilane compound. Stirring is continued while maintaining the internal temperature at 90 ° C., and after 1 hour, the mixture is transferred to a blend tank, 1% by weight of BHT as a stabilizer is added to the polymer, and the solvent is removed using a laboratory drum dryer A polymer was obtained. The resulting polymer was designated as Polymer A.

  As a result of analyzing the polymer A, the amount of bound styrene was 25% by mass, and the amount of bound butadiene was 75%. The Mooney viscosity at 100 ° C. was 57. The vinyl bond content (1,2-vinyl bond content) of the microstructure of the butadiene portion, which was calculated from the measurement result using the infrared spectrophotometer according to the Hampton method, was 52 mol%. The modification rate was 99%. The glass transition temperature was −30 ° C. The analysis results of Polymer A are shown in Table 1.

[Example 2]
Using an autoclave with an internal volume of 11 liters and a temperature-controllable autoclave equipped with a stirrer and a jacket as the reactor, 1,3-butadiene 770 g, 260 g of styrene, 4250 g of cyclohexane, 2, 1.45 g of 2-bis (2-oxolanyl) propane was charged into the reactor, and the reactor internal temperature was maintained at 38 ° C. As a polymerization initiator, a cyclohexane solution containing 13.0 mmol of hexamethyleneiminolithium in which 13.0 mmol of hexamethyleneimine and 13.0 mmol of n-butyllithium were reacted in advance was supplied to the reactor. After the start of the polymerization reaction, the temperature inside the reactor started to rise due to the exotherm caused by the polymerization, and the final temperature inside the reactor reached 90 ° C. Two minutes after reaching the peak of the reaction temperature, 3.25 mmol of N, N, N ′, N′-tetraglycidyl-1,3-bisaminomethylcyclohexane was added to the reactor, and a denaturation reaction was performed for 5 minutes.

  Subsequently, 26 mmol of diethylaminodimethylsilane and a chloroplatinic acid isopropanol solution were added. The chloroplatinic acid used was 0.30 mmol / mol with respect to the hydrosilane compound. Stirring is continued while maintaining the internal temperature at 90 ° C., and after 1 hour, the mixture is transferred to a blend tank, 1% by weight of BHT as a stabilizer is added to the polymer, and the solvent is removed using a laboratory drum dryer A polymer was obtained. The resulting polymer was designated as Polymer B.

  As a result of analyzing the polymer B, the amount of bound styrene was 25% by mass and the amount of bound butadiene was 75%. The Mooney viscosity at 100 ° C. was 63. The vinyl bond content (1,2-vinyl bond content) of the microstructure of the butadiene portion, which was calculated from the measurement result using the infrared spectrophotometer according to the Hampton method, was 52 mol%. The modification rate was 99%. The glass transition temperature was −30 ° C. The analysis results of the polymer B are shown in Table 1.

Example 3
Using an autoclave with an internal volume of 11 liters and a temperature-controllable autoclave equipped with a stirrer and a jacket as the reactor, 1,3-butadiene 770 g, 260 g of styrene, 4250 g of cyclohexane, 2, 1.45 g of 2-bis (2-oxolanyl) propane was charged into the reactor, and the reactor internal temperature was maintained at 38 ° C. As the polymerization initiator, meta-diisopropenylbenzene (7.2 mmol) and sec-butyllithium (14.4 mmol) were used and reacted at 20 ° C. for 6 hours by the method described in Example 1 of JP-B-1-53681. A cyclohexane solution of 7.2 mmol of 1,3-bis (1-lithio-1,3-dimethylpentyl) benzene obtained in this manner was supplied to the reactor. After the start of the polymerization reaction, the temperature inside the reactor started to rise due to the exotherm caused by the polymerization, and the final temperature inside the reactor reached 90 ° C. Two minutes after reaching the peak of the reaction temperature, 14.4 mmol of 3-glycidoxypropyltriethoxysilane was added to the reactor, and a denaturation reaction was performed for 5 minutes.

  Subsequently, 26 mmol of 3-diethylaminopropyldimethylsilane and isopropanol solution of chloroplatinic acid were added. The chloroplatinic acid used was 0.30 mmol / mol with respect to the hydrosilane compound. Stirring is continued while maintaining the internal temperature at 90 ° C., and after 1 hour, the mixture is transferred to a blend tank, 1% by weight of BHT as a stabilizer is added to the polymer, and the solvent is removed using a laboratory drum dryer A polymer was obtained. The resulting polymer was designated as Polymer C.

  As a result of analyzing the polymer C, the amount of bound styrene was 25% by mass and the amount of bound butadiene was 75%. The Mooney viscosity at 100 ° C. was 63. The vinyl bond content (1,2-vinyl bond content) of the microstructure of the butadiene portion, which was calculated from the measurement result using the infrared spectrophotometer according to the Hampton method, was 52 mol%. The modification rate was 99%. The glass transition temperature was −30 ° C. The analysis results of the polymer C are shown in Table 1.

Example 4
7.2 mmol of N, N, N ′, N′-tetramethyl-4,4′-diaminobenzophenone was added to the both-end active butadiene-based polymer solution obtained in the same manner as in Example 3, and the denaturation reaction was performed for 5 minutes. Further, 7.2 mmol of 3- [N, N-bis (trimethylsilyl) amino] propylmethyldiethoxysilane was added and a denaturation reaction was performed for 5 minutes.

  Subsequently, 26 mmol of diethylaminodimethylsilane and a chloroplatinic acid isopropanol solution were added. The chloroplatinic acid used was 0.30 mmol / mol with respect to the hydrosilane compound. Stirring is continued while maintaining the internal temperature at 90 ° C., and after 1 hour, the mixture is transferred to a blend tank, 1% by weight of BHT as a stabilizer is added to the polymer, and the solvent is removed using a laboratory drum dryer A polymer was obtained. The resulting polymer was designated as Polymer D.

  As a result of analyzing the polymer D, the amount of bound styrene was 25% by mass and the amount of bound butadiene was 75%. The Mooney viscosity at 100 ° C. was 63. The vinyl bond content (1,2-vinyl bond content) of the microstructure of the butadiene portion, which was calculated from the measurement result using the infrared spectrophotometer according to the Hampton method, was 52 mol%. The modification rate was 99%. The glass transition temperature was −30 ° C. The analysis results of the polymer D are shown in Table 1.

[Comparative Example 1]
An autoclave with an internal volume of 11 liters and a temperature-controllable autoclave equipped with a stirrer and a jacket was used as a reactor to remove impurities in advance, 770 g of 1,3-butadiene, 260 g of styrene, 4250 g of cyclohexane, 2, 1.0 g of 2-bis (2-oxolanyl) propane was charged into the reactor, and the reactor internal temperature was maintained at 38 ° C. A cyclohexane solution of 7.9 mmol of n-butyllithium was supplied to the reactor as a polymerization initiator. After the start of the polymerization reaction, the temperature in the reactor started to rise due to the exothermic heat of polymerization, and the final temperature in the reactor reached 88 ° C. Two minutes after reaching the peak of the reaction temperature, 3.96 mmol of 3- (dimethylamino) propyltriethoxysilane was added to the reactor, and a denaturation reaction was performed for 5 minutes.

  Then, it transferred to the blend tank, 1 mass% of BHT was added with respect to the polymer as a stabilizer, the solvent was removed using the laboratory drum dryer, and the polymer was obtained. The resulting polymer was designated as Polymer E.

  As a result of analyzing the polymer E, the amount of bound styrene was 25% by mass and the amount of bound butadiene was 75%. The Mooney viscosity at 100 ° C. was 58. The vinyl bond amount (1,2-vinyl bond amount) in the microstructure of the butadiene portion determined by calculation according to the Hampton method from the measurement result using an infrared spectrophotometer was 53 mol%. Further, the modification rate was 80%. The glass transition temperature was -29 ° C. The analysis results of the polymer E are shown in Table 1.

[Comparative Example 2]
Using an autoclave with an internal volume of 11 liters and a temperature-controllable autoclave equipped with a stirrer and a jacket as the reactor, 1,3-butadiene 770 g, 260 g of styrene, 4250 g of cyclohexane, 2, 1.45 g of 2-bis (2-oxolanyl) propane was charged into the reactor, and the reactor internal temperature was maintained at 38 ° C. As a polymerization initiator, a cyclohexane solution of 13.0 mmol of n-butyllithium was supplied to the reactor. After the start of the polymerization reaction, the temperature inside the reactor started to rise due to the exotherm caused by the polymerization, and the final temperature inside the reactor reached 90 ° C. Two minutes after reaching the peak of the reaction temperature, 3.25 mmol of silicon tetrachloride was added to the reactor, and a denaturation reaction was performed for 5 minutes. Subsequently, 26 mmol of diethylaminodimethylsilane and a chloroplatinic acid isopropanol solution were added. The chloroplatinic acid used was 0.25 mmol / mol with respect to the hydrosilane compound. Stirring is continued while maintaining the internal temperature at 90 ° C., and after 1 hour, the mixture is transferred to the blend tank, then transferred to the blend tank, and 1% by mass of BHT as a stabilizer is added to the polymer. Was used to remove the solvent to obtain a polymer. The resulting polymer was designated as Polymer F.

  As a result of analyzing the polymer F, the amount of bound styrene was 25% by mass and the amount of bound butadiene was 75%. The Mooney viscosity at 100 ° C. was 62. The vinyl bond content (1,2-vinyl bond content) of the microstructure of the butadiene portion, which was calculated from the measurement result using the infrared spectrophotometer according to the Hampton method, was 52 mol%. The modification rate was 90%. The glass transition temperature was −30 ° C. The analysis result of the polymer F is shown in Table 1.

[Comparative Example 3]
An autoclave with an internal volume of 11 liters and a temperature-controllable autoclave equipped with a stirrer and a jacket was used as a reactor to remove impurities in advance, 770 g of 1,3-butadiene, 260 g of styrene, 4250 g of cyclohexane, 2, 1.0 g of 2-bis (2-oxolanyl) propane was charged into the reactor, and the reactor internal temperature was maintained at 38 ° C. A cyclohexane solution of 7.9 mmol of n-butyllithium was supplied to the reactor as a polymerization initiator. After the start of the polymerization reaction, the temperature in the reactor started to rise due to the exothermic heat of polymerization, and the final temperature in the reactor reached 88 ° C. Two minutes after reaching the peak of the reaction temperature, 3.96 mmol of 3- (dimethylamino) propyltriethoxysilane was added to the reactor, and a denaturation reaction was performed for 5 minutes. Subsequently, 16 mmol of diethylaminodimethylsilane and an isopropanol solution of chloroplatinic acid were added. The chloroplatinic acid used was 0.25 mmol / mol with respect to the hydrosilane compound. Stirring is continued for 1 hour while maintaining the internal temperature at 88 to 90 ° C., then transferred to a blend tank, 1% by weight of BHT as a stabilizer is added to the polymer, and the solvent is removed using a laboratory drum dryer. Removal gave a polymer. The resulting polymer was designated as Polymer G.

  As a result of analyzing the polymer G, the amount of bound styrene was 25% by mass and the amount of bound butadiene was 75%. The Mooney viscosity at 100 ° C. was 65. The vinyl bond content (1,2-vinyl bond content) of the microstructure of the butadiene portion, which was calculated from the measurement result using the infrared spectrophotometer according to the Hampton method, was 52 mol%. The modification rate was 95%. The glass transition temperature was −30 ° C. The analysis results of the polymer G are shown in Table 1.

＊１
ＮＢＬ ：ノルマルブチルリチウム
ＨＭＩ−Ｌｉ ：ヘキサメチレンイミノリチウム
Ｄｉ−Ｌｉ ：１，３−ビス（１−リチオ−１，３−ジメチルペンチル）ベンゼン
＊２
ＴＧＡＭＣ ：Ｎ，Ｎ，Ｎ’，Ｎ’−テトラグリシジル−１，３−ビスアミノメチ
ルシクロヘキサン
ＴＥＳＰＭＰ ：１−〔３−（トリエトキシシラニル）−プロピル〕−４−メチルピ
ペラジン
ＴＭＤＡＢＰＯ：Ｎ，Ｎ，Ｎ’，Ｎ’−テトラメチル−４，４’−ジアミノベンゾフ
ェノン
ＧＴＥＯＳｉ ：３−グリシドキシプロピルトリエトキシシラン
ＢＳＡＰＥＯＳ：３−〔Ｎ，Ｎ−ビス（トリメチルシリル）アミノ〕プロピルメチル
ジエトキシシラン
ＤＭＡＰＴＥＳ：３−（ジメチルアミノ）プロピルトリエトキシシラン
ＳｉＣＬ４ ：４塩化珪素
＊３
ＤＥＡＳｉＨ ：ジエチルアミノジメチルシラン
ＥＯＳｉＨ ：ジメチルモノエトキシシラン
ＤＥＡＰＳｉＨ：３−ジエチルアミノプロピルジメチルシラン

* 1
NBL: normal butyl lithium HMI-Li: hexamethyleneiminolithium Di-Li: 1,3-bis (1-lithio-1,3-dimethylpentyl) benzene * 2
TGAMC: N, N, N ′, N′-tetraglycidyl-1,3-bisaminomethy
Lucyclohexane TESPMP: 1- [3- (Triethoxysilanyl) -propyl] -4-methylpi
Perazine TMDABPO: N, N, N ′, N′-tetramethyl-4,4′-diaminobenzof
Enon GTEOSi: 3-glycidoxypropyltriethoxysilane BSAPEOS: 3- [N, N-bis (trimethylsilyl) amino] propylmethyl
Diethoxysilane DMAPTES: 3- (dimethylamino) propyltriethoxysilane SiCL4: Silicon tetrachloride * 3
DEASiH: diethylaminodimethylsilane EOSiH: dimethylmonoethoxysilane DEAPSiH: 3-diethylaminopropyldimethylsilane

[Examples 5 to 9, Comparative Examples 4 to 6]
Using the obtained polymers A to F as raw rubbers, rubber compositions containing the raw rubbers were obtained according to the following formulations 1 to 3.

[Formulation 1]
Modified butadiene-based polymer (Samples A, C, E, F, G): 100.0 parts by mass Medium particle size silica (Rhodia Silica Zeosil 1165MP Note 1)
: 60.0 parts by mass Silane coupling agent (Si75 manufactured by Evonik Degussa): 4.8 parts by mass S-RAE oil
(Japan Energy Co., Ltd., JOMO process NC140): 10.0 parts by mass Wax (manufactured by Ouchi Shinsei Chemical Co., Ltd., Sunnock N): 1.5 parts by mass Zinc white: 2.5 parts by mass Stearic acid: 2.0 parts by mass Anti-aging agent (N-isopropyl-N′-phenyl-p-phenylenediamine): 2.0 parts by mass Sulfur: 1.5 parts by mass Vulcanization accelerator (N-cyclohexyl-2-benzothiazylsulfinamide): 1 .3 parts by mass Vulcanization accelerator (diphenylguanidine): 1.6 parts by mass
Total: 179.2 parts by mass Note 1) CTAB specific surface area: 160 m ² / g, BET specific surface area: 165 m ² / g, average primary particle size: 15 nm

[Composition 2]
Modified butadiene-based polymer (sample A): 100.0 parts by mass Fine particle size silica (Silica manufactured by Rhodia)
Zeosil Premium 200MP Note 2): 25.0 parts by mass Large particle size silica (Rhodia Silica Zeosil 1115MP Note 3): 35.0 parts by mass Silane coupling agent (Evonik Degussa Si75): 4.8 parts by mass S -RAE oil
(Japan Energy Co., Ltd., JOMO process NC140): 10.0 parts by mass Wax (manufactured by Ouchi Shinsei Chemical Co., Ltd., Sunnock N): 1.5 parts by mass Zinc white: 2.5 parts by mass Stearic acid: 2.0 parts by mass Anti-aging agent (N-isopropyl-N′-phenyl-p-phenylenediamine): 2.0 parts by mass Sulfur: 1.5 parts by mass Vulcanization accelerator (N-cyclohexyl-2-benzothiazylsulfinamide): 1 .3 parts by mass Vulcanization accelerator (diphenylguanidine): 1.6 parts by mass
Total: 187.2 parts by mass Note 2) CTAB specific surface area: 200 m ² / g, BET specific surface area: 220 m ² / g, average primary particle size: 25 nm, aggregate size: 65 nm
Note 3) CTAB specific surface area: 105 m ² / g, BET specific surface area: 115 m ² / g, average primary particle size: 10 nm, aggregate size: 92 nm

[Formulation 3]
Modified butadiene-based polymer (samples B and D): 100.0 parts by mass Medium-sized silica (silica Zeosil 1165MP manufactured by Rhodia)
: 30.0 parts by mass Carbon black
(Tokai Carbon Co., Ltd., Seast KH (N339)): 30.0 parts by mass Silane coupling agent (Evonik Degussa Si75): 2.5 parts by mass S-RAE oil
(Japan Energy Co., Ltd., JOMO process NC140): 10.0 parts by mass Wax (manufactured by Ouchi Shinsei Chemical Co., Ltd., Sunnock N): 1.5 parts by mass Zinc white: 2.5 parts by mass Stearic acid: 2.0 parts by mass Anti-aging agent (N-isopropyl-N′-phenyl-p-phenylenediamine): 2.0 parts by mass Sulfur: 1.5 parts by mass Vulcanization accelerator (N-cyclohexyl-2-benzothiazylsulfinamide): 1 .3 parts by mass Vulcanization accelerator (diphenylguanidine): 1.6 parts by mass
Total: 185.4 parts by mass

The above materials were kneaded by the following method to obtain a rubber composition.
Using a closed kneader equipped with a temperature control device (with an internal capacity of 0.3 liters), as the first stage kneading, under the conditions of a filling rate of 65% and a rotor rotational speed of 50/57 rpm, the raw rubber (samples A to FG) ), Filler (silica, carbon black), organosilane coupling agent, process oil, zinc white, and stearic acid. At this time, the temperature of the closed mixer was controlled, kneaded for 5 minutes, and a rubber composition was obtained at a discharge temperature (compound) of 155 to 160 ° C. In [Formulation 2], the mixture was kneaded for 8 minutes.

  Next, as the second stage kneading, the mixture obtained above was cooled to room temperature, an anti-aging agent was added, and kneaded again for 4 minutes in order to improve the dispersion of silica. Also in this case, the discharge temperature (formulation) was adjusted to 155 to 160 ° C. by controlling the temperature of the mixer. After cooling, as a third stage of kneading, sulfur and a vulcanization accelerator were added and kneaded with an open roll set at 70 ° C. Thereafter, it was molded and vulcanized with a vulcanization press at 160 ° C. for 20 minutes. After vulcanization, the physical properties of the rubber composition were measured. The physical property measurement results are shown in Table 2.

The physical properties of the rubber composition were measured by the following methods.
(8) Compound Mooney Viscosity Using a Mooney viscometer, according to JIS K6300-1, after preheating at 130 ° C. for 1 minute, the viscosity after rotating the rotor at 2 revolutions per minute for 4 minutes Measured and indexed with the result of Comparative Example 4 taken as 100. It shows that it is excellent in workability, so that a value is small.

(9) Roll workability evaluation Immediately after the kneading in the second stage, the roll skin and roll edge of the kneaded rubber were visually evaluated through three times through an open roll set at 70 ° C. As for roll skin, the surface was smooth and glossy, the surface was smooth but not glossy, and the surface with irregularities was rated as x. As for the roll edge state, a smooth one is indicated by ◯, a slight jagged portion is indicated by Δ, and a large jagged portion is indicated by ×.

(10) 300% modulus, elongation at break Measured according to the method for obtaining tensile properties of JIS K6251 using a dumbbell-shaped specimen No. 5, and indexed with the result of Comparative Example 4 as 100.
The 300% modulus is a tensile stress until the elongation reaches 300%.
Elongation at break is also called elongation at break.

(11) Viscoelastic parameters Using a rheometrics scientific viscoelasticity tester (ARES),
Viscoelastic parameters were measured in torsion mode. Each measured value was indexed with Comparative Example 4 as 100. Tan δ measured at a frequency of 10 Hz and a strain of 1% at 0 ° C. was used as an index of wet grip performance. A larger value indicates better wet grip performance.
Further, tan δ measured at 50 ° C. with a frequency of 10 Hz and a strain of 3% was used as an index of fuel saving performance. The smaller the value, the better the fuel saving performance.
The Pain effect ΔG ′, which is the difference between the storage elastic modulus G ′ measured at a frequency of 10 Hz and a strain of 10% at 50 ° C. and the storage elastic modulus G ′ measured at a strain of 0.1%, was used as an indicator of filler dispersibility. A smaller value indicates better filler dispersion. Furthermore, the storage elastic modulus G ′ measured at 50 ° C. with a frequency of 10 Hz and a strain of 3% was used as an index of rigidity. The greater the value, the higher the rigidity and the higher the running stability when used in a tire.

(12) Abrasion resistance Using an Akron abrasion tester (manufactured by Yasuda Seiki Seisakusho), according to JIS K6264-2, the wear amount of load 44.1N, 1000 rotations was measured, and Comparative Example 4 was indexed as 100. did. The larger the index, the better the wear resistance.

As shown in Table 2, the modified butadiene-based polymer compositions of Examples 5 to 9 have practically sufficient processability (low blended Mooney viscosity) compared to the polymer compositions of Comparative Examples 4 to 6. ) And the dispersibility of the filler is good because the Pain effect ΔG ′, which is the difference in the storage elastic modulus G ′ measured by changing the strain, is small. Furthermore, it was confirmed that tan δ at 50 ° C. was low, hysteresis loss was small, low rolling resistance of the tire was realized, and tan δ at 0 ° C. was high and excellent in wet skid resistance.
In addition, it was confirmed that the rigidity measured by the abrasion resistance and the storage elastic modulus G ′ at 50 ° C. was superior to the polymer rubber composition of Comparative Example 1.

  The modified butadiene-based polymer of the present invention has industrial applicability as a rubbery polymer constituting a rubber composition suitable for tire rubber, anti-vibration rubber, footwear and the like.

Claims (6)

1,3-butadiene is polymerized using an alkali metal compound or alkaline earth metal compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group as a polymerization initiator, or 1,3 A polymerization step of copolymerizing butadiene and a monomer copolymerizable with 1,3-butadiene to obtain a butadiene-based polymer having an active terminal and a polymerization initiation terminal having the functional group;
A compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group at the active terminal of the butadiene-based polymer, or at least selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group A terminal modification step of reacting a compound that forms one type of functional group to introduce the functional group;
A silicon compound having at least one functional group selected from the group consisting of a vinyl group in the main chain of the butadiene-based polymer and an amino group, an alkoxysilyl group, or a hydroxyl group, or an amino group, an alkoxysilyl group, or a hydroxyl group A main chain modification step of modifying the main chain by hydrosilylation reaction with a silicon compound forming at least one functional group selected from the group;
Only including,
In the modified butadiene-based polymer, the amount of 1,2-vinyl bonds in all butadiene units is 25 to 80 mol%.
A method for producing a modified butadiene-based polymer. 1,3-butadiene is polymerized using a polyfunctional initiator, or 1,3-butadiene and a monomer copolymerizable with 1,3-butadiene are copolymerized to have an active end. A polymerization step for obtaining a butadiene-based polymer;
A compound having at least one functional group selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group at the active terminal of the butadiene-based polymer, or at least selected from the group consisting of an amino group, an alkoxysilyl group and a hydroxyl group A terminal modification step of reacting a compound that forms one type of functional group to introduce the functional group at two or more ends;
A silicon compound having at least one functional group selected from the group consisting of a vinyl group in the main chain of the butadiene-based polymer and an amino group, an alkoxysilyl group, or a hydroxyl group, or an amino group, an alkoxysilyl group, or a hydroxyl group A main chain modification step of modifying the main chain by hydrosilylation reaction with a silicon compound forming at least one functional group selected from the group;
Only including,
In the modified butadiene-based polymer, the amount of 1,2-vinyl bonds in all butadiene units is 25 to 80 mol%.
A method for producing a modified butadiene-based polymer.   100 parts by mass of raw rubber containing 20 parts by mass or more of a modified butadiene polymer obtained by the production method according to claim 1 or 2, and 5 to 200 parts by mass of filler are mixed.
  A method for producing a rubber composition.   30 to 100% by mass of the filler is silica.
  The manufacturing method of the rubber composition of Claim 3.   Further cross-linking treatment,
  The manufacturing method of the rubber composition of Claim 3 or 4.   Vulcanization molding of the rubber composition according to claim 5;
  Tire manufacturing method.