JP6432319B2 - Conjugated diene polymer and rubber composition - Google Patents

Description

  The present invention relates to a conjugated diene polymer, and a rubber composition, a crosslinkable rubber composition, a rubber cross-linked product and a tire containing the conjugated diene polymer, and more particularly, has excellent processability. Conjugated diene polymer capable of providing a crosslinked rubber having excellent mechanical strength and chipping resistance, and rubber composition, crosslinked rubber composition, crosslinked rubber and tire containing the conjugated diene polymer About.

  In recent years, automobile tires are required to have excellent mechanical strength due to environmental problems and resource problems. A tire obtained using a rubber composition blended with silica as a filler, while achieving excellent mechanical strength compared to a tire obtained using a rubber composition blended with a conventionally used carbon black, Since low heat generation can be improved, a more fuel-efficient tire can be obtained.

  For example, in Patent Document 1, a rubber component containing a polymer rubber of a conjugated diolefin or a conjugated diolefin and an aromatic vinyl compound and having a protonic amino group in the polymer is added to a specific bis. A rubber composition comprising a maleimide compound, an inorganic filler containing silicic acid, and a silane coupling agent is disclosed. According to Patent Document 1, it is described that a rubber composition having low exothermic properties and excellent storage elastic modulus can be provided.

Japanese Patent No. 4125452

  However, the crosslinked rubber obtained by using the rubber composition disclosed in Patent Document 1 has insufficient mechanical properties, has a low breaking energy, and is inferior in chipping resistance. The reason for this may be that the rubber composition disclosed in Patent Document 1 is not sufficiently dispersed when a filler such as silica is dispersed.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a conjugated diene heavy polymer that has excellent processability and can provide a rubber cross-linked product excellent in mechanical strength and chipping resistance. It is an object of the present invention to provide a polymer composition, and a rubber composition, a crosslinkable rubber composition, a crosslinked rubber product and a tire containing the conjugated diene polymer.

  As a result of intensive studies to achieve the above object, the present inventors have found that a conjugated diene polymer having a thermoreversible bonding group at the end of the polymer chain is excellent in processability, and has mechanical strength and chipping resistance. The present inventors have found that a rubber cross-linked product having excellent properties can be provided, and have completed the present invention.

（上記一般式（１）中、Ｒ^１〜Ｒ^５は、それぞれ独立に、水素原子、炭素数１〜１０のアルキル基、炭素数６〜１２のアリール基、またはハロゲン原子であり、Ｘ^１は、−Ｏ−、−Ｓ−、−Ｓ（＝Ｏ）−、−ＳＯ_２−、−ＮＨ−、−Ｃ（＝Ｏ）−、または−ＯＣ（＝Ｏ）−であり、Ｘ^２は、任意の結合基を表し、Ｐｏｌｙｍｅｒは、共役ジエン単量体単位を含んでなる重合体鎖を表す。） That is, according to the present invention, a conjugated diene polymer having a thermoreversible binding group at the polymer chain end is provided.
The conjugated diene polymer of the present invention is preferably represented by the following general formula (1).

(In the general formula (1), R ^{1 to} R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and X ¹ is , —O—, —S—, —S (═O) —, —SO ₂ —, —NH—, —C (═O) —, or —OC (═O) —, and X ² is optional. (Polymer represents a polymer chain comprising a conjugated diene monomer unit.)

（上記一般式（２）中、Ｒ^６、Ｒ^７は、それぞれ独立に、水素原子、炭素数１〜１０のアルキル基、炭素数６〜１２のアリール基、またはハロゲン原子であり、Ｘ^３は、任意の結合基を表し、ｎは２〜１０の整数である。） According to the present invention, there is provided a rubber composition containing any of the above conjugated diene polymers and a polyfunctional thermoreversible compound.
In the rubber composition of the present invention, the polyfunctional thermoreversible compound is preferably a compound represented by the following general formula (2).

(In the general formula (2), R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and X ³ is Represents an arbitrary bonding group, and n is an integer of 2 to 10.)

Moreover, according to this invention, the crosslinkable rubber composition formed by mix | blending a crosslinking agent with the rubber composition in any one of the said is provided.
Furthermore, according to the present invention, there are provided a rubber cross-linked product obtained by cross-linking the above cross-linkable rubber composition, and a tire comprising the rubber cross-linked product.

  According to the present invention, a conjugated diene polymer capable of providing a rubber cross-linked product having excellent processability and excellent mechanical strength and chipping resistance, and a rubber composition containing the conjugated diene polymer Products, cross-linkable rubber compositions, rubber cross-linked products and tires can be provided.

<Conjugated diene polymer>
The conjugated diene polymer of the present invention has a thermoreversible binding group at the end of the polymer chain.

  The conjugated diene polymer of the present invention is obtained by, for example, polymerizing a monomer mixture containing at least a conjugated diene monomer to obtain a base polymer, and thermally reversible at the polymer chain terminal of the obtained base polymer. It can be obtained by introducing a sex bonding group.

  According to the conjugated diene polymer of the present invention, mechanical strength and chipping resistance when a rubber cross-linked product is obtained while providing excellent processability by providing a thermoreversible bonding group at the end of the polymer chain. The property can be made excellent. In particular, the conjugated diene polymer of the present invention has excellent processability, specifically, Mooney viscosity (polymer Mooney viscosity) before blending a filler such as a crosslinking agent or silica, The difference between Mooney viscosity (compound Mooney viscosity) after blending these can be reduced, and this makes it possible to keep Mooney viscosity fluctuations small regardless of the type of compounding agent. It is easy to design, and the Payne effect (change in storage elastic modulus with respect to dynamic strain) can be kept low, which results in excellent dispersibility of fillers such as silica. Here, the thermoreversible linking group is a group that can reversibly form and dissociate a crosslinked structure due to a temperature change, and exhibits the above effect by reversibly forming and dissociating a crosslinked structure. It is.

  Conventionally, a conjugated diene polymer obtained by silane modification is known, and in such a conventional technique, the interaction with a filler such as silica is enhanced by silane modification, thereby reusing silica. Attempts have been made to suppress aggregation. On the other hand, in the prior art, the initial dispersibility of the filler such as silica is not sufficient, and the performance as a tire (for example, low fuel consumption, etc.) when the rubber cross-linked product is obtained can be sufficiently obtained. It was impossible. On the other hand, for example, a method of improving the initial dispersibility of a filler such as silica by using a conjugated diene polymer as a high molecular weight polymer can be considered. Further, the effect of suppressing the re-aggregation of silica is insufficient, and even in this case, the performance as a tire (for example, low fuel consumption, etc.) in the case of a rubber cross-linked product cannot be sufficiently obtained. .

  On the other hand, in the present invention, by providing a thermoreversible bonding group at the end of the polymer chain, the thermoreversible bonding group forms a crosslinked structure in the initial stage of kneading, so that it behaves as a high molecular weight polymer. Thus, the initial dispersibility of a filler such as silica can be improved. On the other hand, in the latter stage of kneading, the thermoreversible bonding group is dissociated to exhibit the behavior as a low molecular weight polymer, so that the reagglomeration of silica can be well suppressed. It is possible to improve the dispersibility. In addition, by providing a thermoreversible binding group, the fluidity at high temperatures can be improved. And according to this invention, the performance (for example, mechanical strength, chipping resistance, etc.) as a tire in the case of using a rubber cross-linked product can be drastically improved by these actions.

  The conjugated diene monomer is not particularly limited, but 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, 1 , 3-hexadiene and the like. Among these, 1,3-butadiene is preferable because a rubber cross-linked product particularly excellent in low heat build-up and wet grip properties can be obtained.

  The content ratio of the conjugated diene monomer unit in the conjugated diene polymer of the present invention is preferably 50 to 100% by weight, more preferably 55 to 90% by weight, still more preferably 55 to 85% by weight. is there. By making the content rate of a conjugated diene monomer unit into the said range, the wet grip property and abrasion resistance of the tire finally obtained can be improved more.

  The vinyl bond content of the conjugated diene monomer unit contained in the conjugated diene polymer of the present invention is preferably 0 to 80% by weight, more preferably 5 to 70% by weight, and still more preferably 10 to 10% by weight. 65% by weight. By setting the vinyl bond content of the conjugated diene monomer unit within the above range, the low heat buildup of the finally obtained tire can be further enhanced.

  In addition, the base polymer constituting the conjugated diene polymer of the present invention may be a copolymer of another monomer copolymerizable with a conjugated diene monomer. Such other monomers include styrene, α-methyl styrene, 2-methyl styrene, 3-methyl styrene, 4-methyl styrene, 2-ethyl styrene, 3-ethyl styrene, 4-ethyl styrene, 2, Aromatic vinyl monomers such as 4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, vinylnaphthalene, dimethylaminomethylstyrene, dimethylaminoethylstyrene Α, β-unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile; Unsaturated rubonic acid mono- or acid anhydrides such as acrylic acid, methacrylic acid, and maleic anhydride; methyl methacrylate, acrylic Unsaturated carboxylic acid ester monomers such as ethyl acrylate and butyl acrylate; 1 5-hexadiene, 1,6-heptadiene, 1,7-octadiene, non-conjugated diene monomer such as dicyclopentadiene, and 5-ethylidene-2-norbornene; and the like. Among these, aromatic vinyl monomers are preferable, and styrene is particularly preferable.

  The content ratio of other monomer units in the conjugated diene polymer of the present invention is preferably 0 to 50% by weight, more preferably 10 to 45% by weight, still more preferably 15 to 45% by weight. It is.

The thermoreversible bonding group contained at the end of the polymer chain of the conjugated diene polymer of the present invention is a group that can reversibly form and dissociate a cross-linked structure due to a temperature change. The conjugated diene polymer of the present invention is preferably a group represented by the following general formula (3). In this case, the conjugated diene polymer of the present invention is represented by the following general formula (1).

  In the conjugated diene polymer of the present invention, the thermoreversible binding group represented by the general formula (3) is added, for example, with a polyfunctional thermoreversible compound described later and a Diels-Alder reaction. By doing so, the formation and dissociation of the cross-linked structure can occur reversibly due to temperature changes.

In the general formulas (1) and (3), R ^{1 to} R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, X ¹ is —O—, —S—, —S (═O) —, —SO ₂ —, —NH—, —C (═O) —, or —OC (═O) —, preferably And each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and all of which are particularly preferably hydrogen atoms. X ² represents any bonding group, preferably a group containing an electron-donating functional group, preferably a divalent organic group containing a hetero atom, and having 1 to 20 carbon atoms containing a hetero atom The divalent organic group is more preferable. Moreover, O, N, S, Si, etc. are mentioned as a hetero atom in the case where X ² is a divalent organic group containing a hetero atom. From the viewpoint of productivity, at least O as a hetero atom. It is preferable that it is included. Alternatively, depending on the method for introducing a thermoreversible linking group, X ² may be a chemical single bond. Polymer represents a polymer chain comprising a conjugated diene monomer unit. In the present invention, thermoreversibility having a furan skeleton in which X ¹ in the general formulas (1) and (3) is —O— is more effective because the effects of the present invention can be made more remarkable. A linking group is more preferred.

In the conjugated diene polymer of the present invention, the thermoreversible linking group is introduced at the end of the polymer chain, but may be introduced at at least one of the ends of the polymer chain, and may be introduced at both. It may be. Further, the content ratio of the thermoreversible bonding group in the conjugated diene polymer of the present invention is very small because it is introduced at the polymer chain end, and is contained in the conjugated diene polymer. It is usually on the order of 10 × 10 ⁻² to 10 × 10 ⁻⁵ mol with respect to 100 mol of the diene monomer unit.

  In the present invention, a thermoreversible linking group is introduced at the end of the polymer chain. As a technique for introducing a thermoreversible linking group into the side chain of the polymer chain, for example, Japanese Patent No. 4125454. The technique described in the publication is known. When a thermoreversible binding group is introduced into the side chain of the polymer chain as in the technique described in Japanese Patent No. 4125452, improvement of mechanical properties, which is an effect of introducing a thermoreversible binding group In addition, improvement in chipping resistance, particularly improvement in chipping resistance cannot be obtained. In the technique described in Japanese Patent No. 4125452, a thermoreversible linking group is introduced into the side chain of the polymer chain. The introduction ratio is relatively high at 0.1 to 30 mol.

  The weight average molecular weight (Mw) of the conjugated diene polymer of the present invention is not particularly limited, but is usually 100,000 to 3,000,000, preferably as a value measured by gel permeation chromatography in terms of polystyrene. 150,000 to 1,000,000, and more preferably selected within the range of 200,000 to 600,000. By setting the weight average molecular weight within the above range, it is possible to improve the low exothermic property and wet grip property of the obtained rubber cross-linked product while improving the processability.

  Although it does not specifically limit as a manufacturing method of the conjugated diene polymer of this invention, an active terminal is obtained by superposing | polymerizing the monomer mixture containing a conjugated diene monomer in a inert solvent using a polymerization initiator. And a method of reacting a compound having a thermoreversible linking group with the active terminal of the base polymer.

  The inert solvent used for the polymerization is not particularly limited as long as it is usually used in solution polymerization and does not inhibit the polymerization reaction. Specific examples thereof include, for example, aliphatic hydrocarbons such as butane, pentane, hexane, and 2-butene; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and cyclohexene; aromatic carbonization such as benzene, toluene, and xylene. Hydrogen; The amount of the inert solvent used is such that the monomer concentration is usually 1 to 50% by weight, preferably 10 to 40% by weight.

  The polymerization initiator is not particularly limited as long as it can polymerize a monomer mixture containing a conjugated diene monomer to give a base polymer having an active terminal. For example, an organic alkali metal compound In addition, a polymerization initiator having an organic alkaline earth metal compound or a lanthanum series metal compound as a main catalyst is preferably used. Specific examples of the organic alkali metal compound include organic monolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; dilithiomethane, 1,4-dilithiobutane, Examples thereof include organic polyvalent lithium compounds such as 1,4-dilithio-2-ethylcyclohexane and 1,3,5-trilithiobenzene; organic sodium compounds such as sodium naphthalene; and organic potassium compounds such as potassium naphthalene. Examples of the organic alkaline earth metal compound include n-butylmagnesium, n-hexylmagnesium, ethoxycalcium, calcium stearate, t-butoxystrontium, ethoxybarium, isopropoxybarium, ethylmercaptobarium, t-butoxybarium, and phenoxybarium. , Diethylamino barium, barium stearate, ketyl barium and the like. As a polymerization initiator using a lanthanum series metal compound as a main catalyst, a lanthanum series metal salt composed of a lanthanum series metal such as lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, carboxylic acid, phosphorus-containing organic acid, etc. is used as a main catalyst. And a polymerization initiator comprising this and a promoter such as an alkylaluminum compound, an organoaluminum hydride compound, and an organoaluminum halide compound. Among these polymerization initiators, it is preferable to use an organic lithium compound, particularly an organic monolithium compound. In addition, the organic alkali metal compound includes a secondary amine such as dibutylamine, dihexylamine, dibenzylamine, pyrrolidine, hexamethyleneimine, heptamethyleneimine (preferably pyrrolidine, hexamethyleneimine, heptamethyleneimine) and the like. You may make it react and use as an organic alkali metal amide compound. These polymerization initiators can be used alone or in combination of two or more.

  The amount of the polymerization initiator used is usually in the range of 1 to 50 mmol, preferably 2 to 20 mmol, more preferably 4 to 15 mmol per 1000 g of the monomer mixture used for the polymerization.

  Moreover, in order to adjust the vinyl bond content of the conjugated diene monomer unit, when polymerizing the monomer mixture, it is preferable to add a polar compound to an inert solvent used for the polymerization. Examples of the polar compound include ether compounds such as dibutyl ether, tetrahydrofuran and ditetrahydrofurylpropane; tertiary amines such as tetramethylethylenediamine; alkali metal alkoxides; phosphine compounds. Of these, ether compounds and tertiary amines are preferred, tertiary amines are more preferred, and tetramethylethylenediamine is particularly preferred. The amount of the polar compound used is preferably in the range of 0.01 to 100 mol, more preferably 0.3 to 30 mol, with respect to 1 mol of the polymerization initiator. When the amount of the polar compound used is within this range, it is easy to adjust the vinyl bond content of the conjugated diene monomer unit, and problems due to the deactivation of the polymerization initiator hardly occur.

  The polymerization temperature is usually in the range of −78 to 150 ° C., preferably 0 to 100 ° C., more preferably 30 to 90 ° C. As the polymerization mode, any of batch mode and continuous mode can be adopted.

  And a thermoreversible bonding group is introduce | transduced into a polymer chain terminal by making the compound provided with a thermoreversible bonding group react with the active terminal of the base polymer which has an active terminal obtained by such a polymerization reaction. In the present invention, as a method for introducing a thermoreversible linking group into the polymer chain end, a method in which a compound having a thermoreversible linking group is reacted directly with the active end of the base polymer may be employed. From the viewpoint of properties and the like, it is preferable to introduce a thermoreversible linking group to the end of the polymer chain by the method described below.

For example, as a compound having a thermoreversible bonding group, a compound having a functional group represented by X ⁴ H represented by the following general formula (4) (X ⁴ represents O, NH, S, or Si). , Preferably S), and a thermoreversible bonding group can be introduced at the end of the polymer chain by the reaction shown below.

That is, in the above method, a base polymer having an active terminal (expressed by general formula (5). In general formula (5), Polymer represents a base polymer, and M ¹ represents an alkali metal or an alkaline earth metal. Is reacted with the epoxy compound represented by the general formula (6) to obtain the compound represented by the general formula (7). In said general formula (6), R < ⁸ >, R < ⁹ >, R < ¹⁰ >, R < ¹¹ > is a hydrogen atom or a C1-C12 alkyl group each independently, Preferably, R < ⁸ >, R < ⁹ >, R < ¹¹ >. ¹⁰ is a hydrogen atom, and R ¹¹ is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. In addition, as a specific example of the epoxy compound represented by the general formula (6), ethylene oxide and propylene oxide are preferable.

Next, the compound represented by the above general formula (7) obtained by the above reaction is reacted with the compound represented by the above general formula (8) to thereby convert the compound represented by the above general formula (9). obtain. In the general formula ^(8), R ^12, R ^{13, R 14} are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, ^preferably, R ^{12, R 13} is a hydrogen atom , R ¹⁴ is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms. X ⁵ is a halogen atom, preferably chlorine. In addition, as a specific example of the compound represented by the general formula (8), acrylic chloride is preferable.

Then, the compound represented by the above general formula (9) obtained by the above reaction is reacted with a compound having a functional group represented by X ⁴ H represented by the above general formula (4), thereby obtaining the above general formula. The conjugated diene polymer represented by (10) (the conjugated diene polymer of the present invention) can be obtained. When reacting the compound represented by the general formula (9) with the compound having the functional group represented by X ⁴ H represented by the general formula (4), usually triethylamine, triphenylphosphine, etc. The reaction is carried out in the presence of an acid catalyst such as hydrochloric acid, sulfuric acid, aluminum chloride, zinc chloride, tin trifluoromethanesulfonate, or scandium trifluoromethanesulfonate.

Alternatively, using a compound having a functional group represented by X ⁴ H shown in the general formula (4) (X ⁴ represents O, NH, S, or Si, preferably S). A thermoreversible linking group can also be introduced at the end of the polymer chain by the reaction shown below.

That is, in the above method, a base polymer having an active terminal (represented by the general formula (5)) is reacted with the diphenylethylene derivative represented by the above general formula (11) to obtain the above general formula ( The compound represented by 12) is obtained. In said general formula (11), R <^15> , R < ¹⁶ > is a hydrogen atom or a C1-C12 alkyl group each independently, Preferably, R <^15> , R <^16> is a hydrogen atom.

  Next, the compound represented by the above general formula (12) obtained by the above reaction is reacted with the compound represented by the above general formula (8) to thereby convert the compound represented by the above general formula (13). obtain.

Then, the compound represented by the general formula obtained by the above reaction (12), by reacting a compound having a functional group represented by X ^{4 H} shown in the above general formula (4), the general formula The conjugated diene polymer represented by (14) (the conjugated diene polymer of the present invention) can be obtained. When the compound represented by the general formula (12) is reacted with the compound having the functional group represented by X ⁴ H represented by the general formula (4), usually, triethylamine, triphenylphosphine, etc. The reaction is carried out in the presence of an acid catalyst such as hydrochloric acid, sulfuric acid, aluminum chloride, zinc chloride, tin trifluoromethanesulfonate, or scandium trifluoromethanesulfonate.

Alternatively, using a compound having a functional group represented by X ⁴ H shown in the general formula (4) (X ⁴ represents O, NH, S, or Si, preferably S). A thermoreversible linking group can also be introduced at the end of the polymer chain by the reaction shown below.

That is, in the above-described method, the base polymer having the active terminal (represented by the general formula (5)) is reacted with the epihalohydrin derivative represented by the general formula (15) to thereby obtain the general formula (16 ) Is obtained. In the general formula ^{(15), R 17} is an alkylene group having 1 to 12 carbon atoms, preferably a methylene group. R ¹⁸ , R ¹⁹ and R ²⁰ are each independently a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, preferably a hydrogen atom. X ⁶ is a halogen atom, preferably chlorine. In addition, epichlorohydrin is suitable as a specific example of the compound represented by the general formula (15).

Then, the compound represented by the above general formula (16) obtained by the above reaction is reacted with the compound having the functional group represented by X ⁴ H represented by the above general formula (4), thereby the above general formula. A conjugated diene polymer represented by (17) (a conjugated diene polymer of the present invention) can be obtained. When the compound represented by the general formula (16) is reacted with the compound having the functional group represented by X ⁴ H represented by the general formula (4), usually, triethylamine, triphenylphosphine, etc. The reaction is carried out in the presence of an acid catalyst such as hydrochloric acid, sulfuric acid, aluminum chloride, zinc chloride, tin trifluoromethanesulfonate, or scandium trifluoromethanesulfonate.

In addition, a metallized compound represented by the following general formula (18) (M ² represents an alkali metal or an alkaline earth metal, preferably lithium) is used as a compound having a thermoreversible binding group. A thermoreversible linking group can also be introduced at the end of the polymer chain by the reaction shown in.

  That is, in the above-described method, the base polymer having the active terminal (represented by the general formula (5)) is reacted with the epihalohydrin derivative represented by the general formula (15) to thereby obtain the general formula (16 ) Is obtained.

  And the conjugated diene represented by the said General formula (19) is made to react with the compound represented by the said General formula (16) obtained by the said reaction with the metallized compound shown in the said General formula (18). A polymer (a conjugated diene polymer of the present invention) can be obtained.

Further, as a compound having a thermoreversible binding group, a halogenated compound represented by the following general formula (20) (X ⁶ is a halogen atom, preferably chlorine) is used. A thermoreversible linking group can also be introduced at the end of the polymer chain.

  That is, in the above method, a base polymer having an active terminal (represented by the general formula (5)) is reacted with a halogenated compound represented by the following general formula (20), whereby the above general formula (21). A conjugated diene polymer represented by the formula (a conjugated diene polymer of the present invention) can be obtained.

Alternatively, by using the halogenated compound represented by the general formula (20) (X ⁶ is a halogen atom, preferably chlorine), the reaction shown below is performed to form a thermoreversible bonding group at the polymer chain end. Can also be introduced.

  That is, in the above method, the base compound having the active terminal (represented by the general formula (5)) is reacted with the epoxy compound represented by the general formula (6) to thereby obtain the general formula (7). ) Is obtained.

  Then, the conjugated diene represented by the general formula (22) is obtained by reacting the halogenated compound represented by the general formula (20) with the compound represented by the general formula (7) obtained by the reaction. A polymer (a conjugated diene polymer of the present invention) can be obtained.

  Each of the above reactions is usually performed in an inert solvent. As an inert solvent, the solvent used by the polymerization reaction mentioned above can be used without a restriction | limiting, For example, the polymerization solution containing the base polymer which has the active terminal obtained by polymerization reaction can be used as it is. Moreover, as reaction conditions in each said reaction, reaction temperature is 0-100 degreeC normally, Preferably it is the range of 30-90 degreeC, and reaction time is the range of normally 1-120 minutes, Preferably it is 2-60 minutes It is.

In the above reaction, when the compound represented by the general formula (9) is reacted with the compound having the functional group represented by X ⁴ H represented by the general formula (4), the general formula (13) When the compound having the functional group represented by X ⁴ H represented by the general formula (4) is reacted with the compound represented by formula (4), these reactions are carried out from the viewpoint of favorably proceeding these reactions. Before carrying out the step, alcohol or water such as methanol or isopropanol or water is added to the solution containing the compound represented by the general formula (9) or the solution containing the compound represented by the general formula (13). It is preferable to deactivate the terminal.

  In addition, before reacting a compound having a thermoreversible binding group to a base polymer having an active end, a polymerization terminator, a polymerization end modifier, and a coupling agent that are usually used within a range not impairing the effects of the present invention. Or the like may be added to the polymerization system to inactivate a part of the active ends of the base polymer.

  Examples of the polymerization terminal modifier and coupling agent that can be used at this time include N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-methyl-ε-caprolactam, and the like. N-substituted cyclic amides; N-substituted cyclic ureas such as 1,3-dimethylethyleneurea and 1,3-diethyl-2-imidazolidinone; 4,4′-bis (dimethylamino) benzophenone, 4, N-substituted aminoketones such as 4′-bis (diethylamino) benzophenone; aromatic isocyanates such as diphenylmethane diisocyanate and 2,4-tolylene diisocyanate; N, N-disubstituted such as N, N-dimethylaminopropylmethacrylamide Aminoalkylmethacrylamides; 4-N, N-dimethylaminobenza N-substituted aminoaldehydes such as dehydride; N, N-bis (trimethylsilyl) aminopropyltriethoxysilane, N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane, 1-trimethylsilyl-2,2-dimethoxy-1 -Aminoalkoxysilanes such as aza-2-silacyclopentane; N-substituted carbodiimides such as dicyclohexylcarbodiimide; Schiff bases such as N-ethylethylideneimine and N-methylbenzylideneimine; propylene oxide, tetraglycidyl-1, Epoxy group-containing compounds such as 3-bisaminomethylcyclohexane and epoxidized polybutadiene; pyridyl group-containing vinyl compounds such as 4-vinylpyridine; bis (triethoxysilylpropyl) tetrasulfide, bis (to Ributoxysilylpropyl) tetrasulfide, γ-glycidoxypropyltrimethoxysilane, methyltriphenoxysilane, tetramethoxysilane, dimethyldiphenoxysilane, diethyldiphenoxysilane, bis (trimethoxysilyl) methane, bis (trimethoxysilyl) ) Ethane, bis (trimethoxysilyl) propane, bis (trimethoxysilyl) hexane, bis (trimethoxysilyl) nonane, bis (triethoxysilyl) methane, bis (triethoxysilyl) ethane, bis (triethoxysilyl) propane Alkoxy group-containing compounds such as bis (triethoxysilyl) hexane and bis (triethoxysilyl) nonane; tin tetrachloride, silicon tetrachloride, triphenoxychlorosilane, hexachlorosilane, bis (trichlorosilyl) ) Methane, bis (trichlorosilyl) ethane, bis (trichlorosilyl) propane, bis (trichlorosilyl) hexane, halogenated metal compounds such as bis (trichlorosilyl) nonane; and the like.

  As described above, after reacting a base polymer having an active terminal with a compound having a thermoreversible binding group, aging prevention of a phenol stabilizer, a phosphorus stabilizer, a sulfur stabilizer, etc., as desired. After adding an agent, a crumbing agent, a scale inhibitor, etc. to the reaction solution, the reaction solvent is separated from the reaction solution by direct drying or steam stripping to recover the desired conjugated diene polymer. Before separating the reaction solvent from the reaction solution, an extending oil may be mixed into the reaction solution, and the conjugated diene polymer may be recovered as an oil-extended rubber.

  As the extender oil used when recovering the conjugated diene polymer as an oil-extended rubber, those normally used in the rubber industry can be used, including paraffinic, aromatic and naphthenic petroleum softeners, plant softening Agents, fatty acids and the like. When using a petroleum softener, the polycyclic aromatic content is preferably less than 3%. This content is measured by the method of IP346 (the testing method of THE INSTITUTE PETROLEUM, UK). When using the extender oil, the amount used is usually 5 to 100 parts by weight, preferably 10 to 60 parts by weight, more preferably 20 to 50 parts by weight with respect to 100 parts by weight of the conjugated diene polymer. .

<Rubber composition>
The rubber composition of the present invention contains the above-described conjugated diene polymer of the present invention and a polyfunctional thermoreversible compound.

  The polyfunctional thermoreversible compound is not particularly limited, but the thermoreversible bonding group provided in the above-described conjugated diene polymer of the present invention can form a cross-linked structure and dissociate due to temperature change. Is a compound having two or more groups capable of causing reversibility, and more specifically, a group capable of reversibly forming and dissociating a cross-linked structure due to temperature change by addition reaction by Diels-Alder reaction. A compound having two or more is preferable.

（上記一般式（２）中、Ｒ^６、Ｒ^７は、それぞれ独立に、水素原子、炭素数１〜１０のアルキル基、炭素数６〜１２のアリール基、またはハロゲン原子であり、Ｘ^３は、任意の結合基を表し、ｎは２〜１０の整数である。） Although it does not specifically limit as a compound which shows such a polyfunctional thermoreversibility, The compound represented by following General formula (2) from viewpoints, such as reactivity, is preferable.

(In the general formula (2), R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and X ³ is Represents an arbitrary bonding group, and n is an integer of 2 to 10.)

（上記一般式（２３）中、Ｒ^６、Ｒ^７は、上記一般式（２）と同様であり、Ｘ^７は、炭素数１〜１００の直鎖または分岐状のアルキレン基、または、下記一般式（２４）〜（２７）で表されるいずれかの基である。）

上記一般式（２４）〜（２７）中、Ｒ^２１〜Ｒ^３０は、水素原子、炭素数１〜６のアルキル基、炭素数６〜１２のアリール基、または、ハロゲン原子であり、これらは互いに同一であっても相違していてもよい。Ｘ^８〜Ｘ^１３は、化学的な単結合、炭素数１〜１０の分岐または直鎖状のアルキレン基、−Ｏ−、−Ｓ−、−ＳＯ_２−、−Ｃ（＝Ｏ）−、または、−Ｓ（＝Ｏ）−であり、これらは互いに同一であっても相違していてもよい。 Among them, as a compound exhibiting polyfunctional thermoreversibility, the compound represented by the following general formula (23) in which n is 2 in the general formula (2) from the viewpoint that the reactivity can be further improved. The bismaleimide compound represented by) is more preferred.

(In the general formula (23), R ⁶ and R ⁷ are the same as in the general formula (2), and X ⁷ is a linear or branched alkylene group having 1 to 100 carbon atoms, or (It is any group represented by Formulas (24) to (27).)

In the general formulas (24) to (27), R ^{21 to} R ³⁰ are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom. They may be the same or different. X ^{8 to} X ^{13 each} represents a chemical single bond, a branched or linear alkylene group having 1 to 10 carbon atoms, —O—, —S—, —SO ₂ —, —C (═O) —, or , -S (= O)-, which may be the same as or different from each other.

As the compound represented by the general formula (23), those in which X ⁷ is a linear or branched alkylene group having 1 to 100 carbon atoms are compatible with the conjugated diene polymer of the present invention described above. In particular, it is preferable from the viewpoint of easily obtaining a uniform rubber composition.

In addition, as a compound represented by the general formula (23), a compound in which X ⁷ is any one of the general formulas (24) to (27) has a maleimide structure because of the electron withdrawing property of the phenyl group. The electron density of the contained carbon-carbon double bond can be lowered, and this is preferable from the viewpoint that the addition reaction by the Diels-Alder reaction can be more easily caused.

  In the present invention, by blending a filler such as silica with a conjugated diene polymer of the present invention described above and blending a compound such as silica, kneading and the like, In the initial stage of kneading, a crosslinked structure is formed between the thermoreversible bonding group provided in the conjugated diene polymer and the polyfunctional thermoreversible compound, thereby exhibiting a behavior as a high molecular weight polymer. Thereby, the initial dispersibility of fillers, such as a silica, can be improved. On the other hand, in the latter stage of kneading, the thermoreversible binding group and the polyfunctional thermoreversible compound are dissociated to show the behavior as a low molecular weight polymer, thereby filling silica or the like. It is possible to satisfactorily suppress reaggregation of the agent, thereby improving the dispersibility of the filler such as silica. According to the present invention, these functions dramatically improve the performance as a tire (for example, mechanical strength, chipping resistance, etc.) when a rubber cross-linked product is realized while achieving excellent processability. It can be made to.

A compound for introducing the thermally reversible linking group conjugated diene polymer, a compound having a functional group represented by X ^{4 H} shown in the above general formula ⁽⁴⁾ (X 4 are, O, NH, S, Or a compound that represents Si and is preferably S, and is a polyfunctional thermoreversible compound as a bismaleimide compound represented by the general formula (23) (in the general formula (23), When the case of using a bismaleimide compound in which R ⁶ and R ⁷ are hydrogen atoms is exemplified, these crosslinking and dissociation reactions are represented by the following formula (28).

  In addition, the compounding amount of the polyfunctional thermoreversible compound in the rubber composition of the present invention is appropriately selected according to the amount and type of the thermoreversible binding group contained in the conjugated diene polymer. However, the amount is preferably 0.01 to 20 moles, more preferably 0.05 to 15 moles, and still more preferably 0.8 to 1 mole of the thermoreversible bonding group contained in the conjugated diene polymer. 1 to 10 moles. By setting the blending amount of the polyfunctional thermoreversible compound within the above range, it is possible to further improve the low heat build-up and wet grip properties of the resulting rubber cross-linked product while improving processability. .

Moreover, the Mooney viscosity (ML1 _{+ 4} , 100 degreeC) of the rubber composition of this invention becomes like this. Preferably it is 20-100, More preferably, it is 30-90, Most preferably, it is 35-80.

<Crosslinkable rubber composition>
The crosslinkable rubber composition of the present invention is obtained by blending a crosslinker with the above-described rubber composition of the present invention.

  Examples of the crosslinking agent include sulfur, sulfur halides, organic peroxides, quinonedioximes, organic polyvalent amine compounds, and alkylphenol resins having a methylol group. Among these, sulfur is preferably used. The amount of the crosslinking agent is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight, and particularly preferably 1 to 4 parts by weight with respect to 100 parts by weight of the rubber component in the rubber composition. It is.

The crosslinkable rubber composition of the present invention preferably further contains silica. Examples of the silica used in the present invention include dry method white carbon, wet method white carbon, colloidal silica, and precipitated silica. Among these, wet method white carbon mainly containing hydrous silicic acid is preferable. Alternatively, a carbon-silica dual phase filler in which silica is supported on the carbon black surface may be used. These silicas can be used alone or in combination of two or more. Is (measured by the BET method according to ASTM D3037-81) nitrogen adsorption specific surface area of silica used is preferably 50 to 300 m ² / g, more preferably 80~250m ² / g, particularly preferably 100~220m ² / g. Moreover, it is preferable that the pH of a silica is pH 5-10.

  The amount of silica in the crosslinkable rubber composition of the present invention is preferably 10 to 200 parts by weight, more preferably 30 to 150 parts by weight, with respect to 100 parts by weight of the rubber component in the crosslinkable rubber composition. More preferably, it is 50-100 weight part. By making the compounding quantity of silica into the above range, the processability of the crosslinkable rubber composition can be further enhanced.

  The crosslinkable rubber composition of the present invention preferably further contains a silane coupling agent. Examples of the silane coupling agent include vinyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, 3-octathio- 1-propyl-triethoxysilane, bis (3- (triethoxysilyl) propyl) disulfide, bis (3- (triethoxysilyl) propyl) tetrasulfide, γ-trimethoxysilylpropyldimethylthiocarbamyl tetrasulfide, γ- And trimethoxysilylpropylbenzothiazyl tetrasulfide.

  The compounding amount of the silane coupling agent in the crosslinkable rubber composition of the present invention is preferably 0.1 to 30 parts by weight, more preferably 1 to 15 parts by weight with respect to 100 parts by weight of silica.

  The crosslinkable rubber composition of the present invention may further contain carbon black such as furnace black, acetylene black, thermal black, channel black, and graphite. Among these, furnace black is preferable. These carbon blacks can be used alone or in combination of two or more. The compounding amount of carbon black is usually 120 parts by weight or less with respect to 100 parts by weight of the rubber component in the rubber composition.

  Furthermore, in addition to the above components, the crosslinkable rubber composition of the present invention includes a crosslinking accelerator, a crosslinking activator, an anti-aging agent, a filler (excluding silica and carbon black), an activator, according to a conventional method. A necessary amount of compounding agents such as process oil, plasticizer, lubricant, and tackifier can be blended.

  When sulfur or a sulfur-containing compound is used as the crosslinking agent, it is preferable to use a crosslinking accelerator and a crosslinking activator in combination. Examples of the crosslinking accelerator include sulfenamide-based crosslinking accelerators; guanidine-based crosslinking accelerators; thiourea-based crosslinking accelerators; thiazole-based crosslinking accelerators; thiuram-based crosslinking accelerators; dithiocarbamic acid-based crosslinking accelerators; A crosslinking accelerator; and the like. Among these, those containing a sulfenamide-based crosslinking accelerator are preferable. These crosslinking accelerators are used alone or in combination of two or more. The blending amount of the crosslinking accelerator is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight, particularly preferably 1 to 1 part by weight based on 100 parts by weight of the rubber component in the crosslinkable rubber composition. 4 parts by weight.

  Examples of the crosslinking activator include higher fatty acids such as stearic acid; zinc oxide. These crosslinking activators are used alone or in combination of two or more. The amount of the crosslinking activator is preferably 0.05 to 20 parts by weight, particularly preferably 0.5 to 15 parts by weight, based on 100 parts by weight of the rubber component in the crosslinkable rubber composition.

  Moreover, you may mix | blend other rubbers other than the conjugated diene polymer mentioned above with the crosslinkable rubber composition of this invention. Examples of other rubbers include natural rubber, polyisoprene rubber, emulsion polymerization styrene-butadiene copolymer rubber, solution polymerization styrene-butadiene copolymer rubber, and polybutadiene rubber (high cis-BR and low cis BR may be used. Further, it may be a polybutadiene rubber containing crystal fibers made of 1,2-polybutadiene polymer), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, acrylonitrile-butadiene. Among copolymer rubbers, acrylonitrile-styrene-butadiene copolymer rubbers and the like, those other than the conjugated diene polymer of the present invention described above are mentioned. Among these, natural rubber, polyisoprene rubber, polybutadiene rubber, and solution-polymerized styrene-butadiene copolymer rubber are preferable. These rubbers can be used alone or in combination of two or more.

  In the crosslinkable rubber composition of the present invention, the conjugated diene polymer described above preferably accounts for 10 to 100% by weight, particularly 50 to 100% by weight, of the rubber component in the crosslinkable rubber composition. preferable. By including the conjugated diene polymer described above in the rubber component at such a ratio, the low exothermic property of the crosslinked rubber can be further increased.

  In order to obtain the crosslinkable rubber composition of the present invention, each component may be kneaded according to a conventional method. For example, a rubber composition containing the above-described conjugated diene polymer and a polyfunctional thermoreversible compound. Ingredients are blended with ingredients other than heat labile components such as crosslinking agents and crosslinking accelerators, kneaded with a mixer, etc., and then the obtained kneaded product is unstable to heat such as crosslinking agents and crosslinking accelerators. The desired composition can be obtained by mixing various components. Under the present circumstances, in this invention, the kneading | mixing temperature of the component except a heat unstable component becomes like this. Preferably it is 80-200 degreeC, More preferably, it is 100-180 degreeC.

<Rubber cross-linked product>
The rubber cross-linked product of the present invention is obtained by cross-linking the cross-linkable rubber composition of the present invention described above.
The rubber cross-linked product of the present invention uses the cross-linkable rubber composition of the present invention and is molded by a molding machine corresponding to a desired shape, for example, an extruder, an injection molding machine, a compressor, a roll, etc., and heated. It can manufacture by performing a crosslinking reaction and fixing a shape as a crosslinked product. In this case, crosslinking may be performed after molding in advance, or crosslinking may be performed simultaneously with molding. The molding temperature is usually 10 to 200 ° C, preferably 25 to 120 ° C. The crosslinking temperature is usually 100 to 200 ° C, preferably 130 to 190 ° C, and the crosslinking time is usually 1 minute to 24 hours, preferably 2 minutes to 12 hours, particularly preferably 3 minutes to 6 hours. .

  Further, depending on the shape and size of the rubber cross-linked product, even if the surface is cross-linked, it may not be sufficiently cross-linked to the inside. Therefore, secondary cross-linking may be performed by heating.

  As a heating method, a general method used for crosslinking of rubber such as press heating, steam heating, oven heating, and hot air heating may be appropriately selected.

  The rubber cross-linked product of the present invention thus obtained is obtained by using the cross-linkable rubber composition of the present invention described above, and therefore has excellent mechanical strength and chipping resistance. The rubber cross-linked product of the present invention makes use of such characteristics, and for example, in tires, materials for tire parts such as cap treads, base treads, carcass, sidewalls and bead parts; hoses, belts, mats, It can be used in various applications such as vibration rubber and other various industrial article materials; resin impact resistance improvers; resin film buffers; shoe soles; rubber shoes; golf balls; In particular, the rubber cross-linked product of the present invention can be suitably used in various parts of a tire such as a tread, a carcass, a sidewall, and a bead part in various tires such as an all-season tire, a high-performance tire, and a studless tire, In particular, by adding silica, it can be made excellent in low heat build-up, and therefore can be particularly suitably used for treads of low fuel consumption tires.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples. In the following, “part” is based on weight unless otherwise specified. Moreover, the test and evaluation followed the following.

(Weight average molecular weight, number average molecular weight, molecular weight distribution)
The weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution (Mw / Mn) were obtained by obtaining a chart based on the molecular weight in terms of polystyrene by gel permeation chromatography. The specific measurement conditions for gel permeation chromatography were as follows.
Measuring instrument: High performance liquid chromatograph (trade name “HLC-8220” manufactured by Tosoh Corporation)
Column: Two Tosoh product names "GMH-HR-H" were connected in series.
Detector: Differential refractometer (trade name “RI-8020” manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Column temperature: 40 ° C

[Styrene content and vinyl bond content]
The styrene content and the vinyl bond content were measured by ¹ H-NMR using a FT-NMR apparatus (product name: ADVANCE III 500) manufactured by Bruker BioSpin.

[Content ratio of thermoreversible linking group]
The content ratio of the thermoreversible bonding group was measured by ¹ H-NMR using a FT-NMR apparatus (product name: ADVANCE III 500) manufactured by Bruker BioSpin.

[Change in Mooney viscosity (ML _{1 + 4} , 100 ° C.)]
The Mooney viscosity (polymer Mooney viscosity) of the rubber composition and the Mooney viscosity (compound Mooney viscosity) of the crosslinkable rubber composition are measured using a Mooney viscometer (manufactured by Shimadzu Corporation) in accordance with JIS K6300. From the obtained results, the amount of change in Mooney viscosity was calculated according to “change amount of Mooney viscosity = (compound Mooney viscosity) − (polymer Mooney viscosity)”. It can be determined that the smaller the change in Mooney viscosity, the better the processability.

[Pain effect]
The Payne effect uses a crosslinkable rubber composition and is stored at a dynamic strain of 1% and 10% under the conditions of 60 ° C. and 1 Hz using a viscoelasticity measuring apparatus (product name “RPA-2000” manufactured by Alpha Technologies Co., Ltd.). Viscosity G ′ was measured, and the difference between storage viscosities G ′ at 1% dynamic strain and storage viscosities G ′ at 10% dynamic strain (ΔG ′ = G ′ (1%) − G ′ (10%)) was calculated. About the obtained difference, it showed with the index | exponent which sets the measured value of the comparative example 1 to 100, respectively. It can be judged that the smaller the index, the better the dispersibility of the filler such as silica, and the better the workability.

[Tensile breaking strength and breaking elongation of crosslinked rubber]
A test piece having a length of 50 mm, a width of 12.7 mm, and a thickness of 2 mm was obtained by press-crosslinking the crosslinkable rubber composition at 160 ° C. for 20 minutes. And the tensile test was done according to JISK6301 using the obtained test piece, and breaking strength and breaking elongation were measured. In addition, it can be judged that it is excellent in mechanical strength, so that breaking strength and breaking elongation are large.

[Break energy]
A test piece having a length of 50 mm, a width of 12.7 mm, and a thickness of 2 mm was obtained by press-crosslinking the crosslinkable rubber composition at 160 ° C. for 20 minutes. And using the obtained test piece, the tension test was done according to JISK6301, the stress-strain curve until a fracture | rupture was calculated | required, and the area of the stress-strain curve was made into fracture energy. An index with the measured value of the obtained breaking energy and the measured value of Comparative Example 1 as 100 was obtained, and the chipping resistance was evaluated. It can be evaluated that the larger the measured value and index value of the breaking energy, the better the chipping resistance.

[Production Example 1: Production of rubber composition A containing conjugated diene polymer a and 4,4′-bismaleimide diphenylmethane]
An autoclave equipped with a stirrer was charged with 800 g of cyclohexane, 1.44 mmol of tetramethylethylenediamine, 94.8 g (1.76 mol) of 1,3-butadiene, and 25.2 g (0.24 mol) of styrene in a nitrogen atmosphere, and then n- 0.80 mmol of butyl lithium was added and polymerization was started at 50 ° C. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 1.60 mmol of propylene oxide was added and reacted at 25 ° C. for 60 minutes, and further 1.60 mmol of acryl chloride was added. And reacted for 60 minutes. Thereafter, methanol was added as a polymerization terminator in an amount corresponding to twice the mole of n-butyllithium used.

  Next, the temperature was raised to 80 ° C. and 4.00 mmol of triethylamine and 8.00 mmol of furfurylthiol were added and reacted for 3 hours. Then, Irganox 1520L (manufactured by BASF) was used as an anti-aging agent. After adding 0.20 parts to 100 parts of the combined polymer, the solvent was removed by steam stripping, followed by vacuum drying at 60 ° C. for 24 hours to obtain a conjugated diene polymer a.

As a result of measuring ¹ H-NMR for the obtained conjugated diene polymer a, a signal derived from furan was observed, and it was confirmed that furan was introduced at the end of the polymer chain. The introduction rate of the furan structure per single chain of the conjugated diene polymer a was 70%. Further, the conjugated diene polymer a obtained had a styrene content of 21.0% by weight and a vinyl bond content in the butadiene monomer unit of 63.5% by weight. Moreover, in GPC measurement, Mn was 256,000 as a whole, Mw was 333,000, and molecular weight distribution (Mw / Mn) was 1.30.

Next, 110 g of the obtained conjugated diene polymer a was dissolved in 500 ml of toluene, and 0.23 mmol of 4,4′-bismaleimide diphenylmethane as a compound showing polyfunctional thermoreversibility was added. The solvent was removed by ripping and vacuum-dried at 60 ° C. for 24 hours to obtain a solid rubber composition A. As a result of measuring ¹ H-NMR for the obtained rubber composition A, the peak of the furan adduct of 4,4′-bismaleimide diphenylmethane was confirmed.

[Production Example 2: Production of rubber composition B containing conjugated diene polymer b and 4,4′-bismaleimide diphenylmethane]
A conjugated diene polymer b was obtained in the same manner as in Production Example 1 except that the amount of furfurylthiol added was changed from 8.00 mmol to 3.00 mmol. As a result of measuring ¹ H-NMR for the obtained conjugated diene polymer b, a signal derived from furan was observed, and it was confirmed that furan was introduced at the end of the polymer chain. The introduction rate of the furan structure per single chain of the conjugated diene polymer b was 30%. The conjugated diene polymer b thus obtained had a styrene content of 20.8% by weight and a vinyl bond content in the butadiene monomer unit of 64.1% by weight. Moreover, in GPC measurement, Mn was 238,000 as a whole, Mw was 313,000, and molecular weight distribution (Mw / Mn) was 1.32.

Next, 110 g of the conjugated diene polymer b thus obtained was dissolved in 500 ml of toluene, 0.10 mmol of 4,4′-bismaleimide diphenylmethane was added, the solvent was removed by steam stripping, and the mixture was heated at 60 ° C. for 24 hours. The solid rubber composition B was obtained by vacuum drying. As a result of measuring ¹ H-NMR for the obtained rubber composition B, the peak of a furan adduct of 4,4′-bismaleimide diphenylmethane was confirmed.

[Production Example 3: Production of Conjugated Diene Polymer c]
An autoclave equipped with a stirrer was charged with 800 g of cyclohexane, 1.44 mmol of tetramethylethylenediamine, 94.8 g (1.76 mol) of 1,3-butadiene, and 25.2 g (0.24 mol) of styrene in a nitrogen atmosphere, and then n- 0.80 mmol of butyl lithium was added and polymerization was started at 50 ° C. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, as a polymerization terminator, an amount of methanol corresponding to twice the mole of n-butyllithium used was added, A solution containing the conjugated diene polymer c was obtained. Further, Irganox 1520L (manufactured by BASF) as an anti-aging agent was added in an amount of 0.20 part to 100 parts of the conjugated diene polymer, and then the solvent was removed by steam stripping, followed by vacuum drying at 60 ° C. for 24 hours. As a result, a conjugated diene polymer c was obtained. As a result of measuring ¹ H-NMR for the obtained conjugated diene polymer c, the styrene content was 21.2%, and the vinyl bond content in the butadiene monomer unit was 63.8%. Moreover, in GPC measurement, Mn was 211,000 as a whole, Mw was 220,000, and molecular weight distribution (Mw / Mn) was 1.03.

[Production Example 4: Production of rubber composition D containing conjugated diene polymer d and 4,4′-bismaleimide diphenylmethane]
An autoclave equipped with a stirrer was charged with 800 g of cyclohexane, 1.44 mmol of tetramethylethylenediamine, 94.8 g (1.76 mol) of 1,3-butadiene, and 25.2 g (0.24 mol) of styrene in a nitrogen atmosphere, and then n- 0.80 mmol of butyl lithium was added and polymerization was started at 50 ° C. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 0.05 mmol of tin tetrachloride was added and reacted for 30 minutes.

Next, the state of a 20% concentration xylene solution is used so that the polyorganosiloxane represented by the following formula (29) has an epoxy group content corresponding to 0.2 mol of n-butyllithium used. And reacted for 30 minutes. Thereafter, as a polymerization terminator, an amount of methanol corresponding to twice the mole of n-butyllithium used was added to obtain a solution containing a conjugated diene polymer whose terminal was silanol-modified.

  Next, 0.86 ml (8.47 mmol) of furfurylthiol and 0.46 g (2.82 mmol) of 2,2′-azobisisobutyronitrile were added to this solution, and the mixture was stirred at 70 ° C. for 5 hours. Irganox 1520L (manufactured by BASF) as an anti-aging agent was added to 0.20 parts of silanol-modified conjugated diene polymer, and the solvent was removed by steam stripping. By vacuum drying for a time, a conjugated diene polymer d was obtained.

As a result of measuring ¹ H-NMR for the obtained conjugated diene polymer d, a signal derived from furan was observed, and it was confirmed that furan was introduced into the side chain. The introduction rate of the furan structure per single chain of the conjugated diene polymer d was 70%. The conjugated diene polymer d thus obtained had a styrene content of 20.4% by weight and a vinyl bond content in the butadiene monomer unit of 64.0% by weight. Moreover, in GPC measurement, Mn was 276,000 as a whole, Mw was 412,000, and molecular weight distribution (Mw / Mn) was 1.50.

Next, 110 g of the obtained conjugated diene polymer d was dissolved in 500 ml of toluene, and after adding 0.26 mmol of 4,4′-bismaleimide diphenylmethane as a polyfunctional thermoreversible compound, The solvent was removed by ripping and vacuum-dried at 60 ° C. for 24 hours to obtain a solid rubber composition D. As a result of measuring ¹ H-NMR for the obtained rubber composition D, the peak of the furan adduct of 4,4′-bismaleimide diphenylmethane was confirmed.

[Production Example 5: Production of conjugated diene polymer e]
An autoclave equipped with a stirrer was charged with 800 g of cyclohexane, 1.44 mmol of tetramethylethylenediamine, 94.8 g (1.76 mol) of 1,3-butadiene, and 25.2 g (0.24 mol) of styrene in a nitrogen atmosphere, and then n- 0.80 mmol of butyl lithium was added and polymerization was started at 50 ° C. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 0.05 mmol of tin tetrachloride was added and reacted for 30 minutes.

Next, the state of a 20% concentration xylene solution is used so that the polyorganosiloxane represented by the above formula (29) has an epoxy group content corresponding to 0.2-fold mol of n-butyllithium used. And reacted for 30 minutes. Thereafter, as a polymerization terminator, an amount of methanol corresponding to twice the mole of n-butyllithium used was added to obtain a solution containing a conjugated diene polymer e whose terminal was silanol-modified. Further, as an anti-aging agent, Irganox 1520L (manufactured by BASF) was added in an amount of 0.20 part to 100 parts of a silanol-modified conjugated diene polymer, and then the solvent was removed by steam stripping at 60 ° C. The conjugated diene polymer e was obtained by vacuum drying for 24 hours.
As a result of measuring ¹ H-NMR for the obtained conjugated diene polymer e, the styrene content of the conjugated diene polymer e was 21.1% by weight, and the vinyl bond content in the butadiene monomer unit was 64. 0.5% by weight. Moreover, in GPC measurement, Mn was 274,000 as a whole, Mw was 391,000, and molecular weight distribution (Mw / Mn) was 1.43.

[Production Example 6: Production of rubber composition F containing conjugated diene polymer e and 4,4'-bismaleimide diphenylmethane]

  110 g of the conjugated diene polymer e obtained in Production Example 5 was dissolved in 500 ml of toluene, and 0.26 mmol of 4,4′-bismaleimide diphenylmethane as a compound showing polyfunctional thermoreversibility was added, and then steam was added. The solvent was removed by stripping, followed by vacuum drying at 60 ° C. for 24 hours to obtain a solid rubber composition F.

[Example 1]
Using a Banbury mixer with a capacity of 250 ml, 70 parts of rubber composition A containing conjugated diene polymer a obtained in Production Example 1, 4,4′-bismaleimide diphenylmethane, and 30 parts of natural rubber were mixed. Kneaded. Next, silica (trade name “Zeosil 1165MP”, manufactured by Rhodia, nitrogen adsorption specific surface area (BET method): 160 m ² / g), 40 parts of silane coupling agent (bis (3- (triethoxysilyl) propyl) tetrasulfide, Add 4.8 parts of the trade name “Si69” (Degussa) and 5 parts of process oil (trade name “Fukor Eramic 30”, Shin Nippon Oil Co., Ltd.) and start at 110 ° C. for 1.5 minutes. Kneaded. To this kneaded product, silica (trade name “Zeosil 1165MP”, manufactured by Rhodia, 20 parts of nitrogen adsorption specific surface area (BET method): 160 m ² / g), 3.0 parts of zinc oxide (Zinc Hana 1), stearic acid ( Trade name “Tubeki bead stearate” (manufactured by NOF Corporation), and anti-aging agent (N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine, trade name “NOCRACK 6C”, 2 parts of Ouchi Shinsei Chemical Co., Ltd.) was added and kneaded for 2.5 minutes, and the kneaded product was discharged from the Banbury mixer. The temperature of the kneaded product at the end of kneading was 150 ° C. Next, the kneaded product was cooled to room temperature and then kneaded again in a Banbury mixer for 3 minutes, and then the kneaded product was discharged from the Banbury mixer. Next, using an open roll at 50 ° C., the obtained kneaded product, 1.6 parts of sulfur and a crosslinking accelerator (N-cyclohexyl-2-benzothiazolylsulfenamide (trade name “Noxeller CZ-G”, After kneading 1.4 parts of Ouchi Shinsei Chemical Co., Ltd.) and 1.4 parts of diphenylguanidine (trade name “Noxeller D”, made by Ouchi Shinsei Chemical Co., Ltd.)), sheet-like cross-linking The rubber composition was taken out.

  Each said evaluation was performed using the obtained crosslinkable rubber composition. The results are shown in Table 2.

[Example 2]
In place of the rubber composition A containing the conjugated diene polymer a obtained in Production Example 1 and 4,4′-bismaleimide diphenylmethane, the conjugated diene polymer b obtained in Production Example 2; A crosslinkable rubber composition was prepared and evaluated in the same manner as in Example 1 except that the rubber composition B containing 4,4′-bismaleimide diphenylmethane was used. The results are shown in Table 2.

[Comparative Example 1]
Instead of the rubber composition A containing the conjugated diene polymer a obtained in Production Example 1 and 4,4′-bismaleimide diphenylmethane, the conjugated diene polymer c obtained in Production Example 3 is used. Except for the above, a crosslinkable rubber composition was prepared in the same manner as in Example 1 and evaluated in the same manner. The results are shown in Table 2.

[Comparative Example 2]
Instead of the rubber composition A containing the conjugated diene polymer a obtained in Production Example 1 and 4,4′-bismaleimide diphenylmethane, the conjugated diene polymer d obtained in Production Example 4; A crosslinkable rubber composition was prepared in the same manner as in Example 1 except that the rubber composition D containing 4,4′-bismaleimide diphenylmethane was used, and evaluated in the same manner. The results are shown in Table 2.

[Comparative Example 3]
Instead of the rubber composition A containing the conjugated diene polymer a obtained in Production Example 1 and 4,4′-bismaleimide diphenylmethane, the conjugated diene polymer e obtained in Production Example 5 is used. Except for the above, a crosslinkable rubber composition was prepared in the same manner as in Example 1 and evaluated in the same manner. The results are shown in Table 2.

[Comparative Example 4]
Instead of the rubber composition A containing the conjugated diene polymer a obtained in Production Example 1 and 4,4′-bismaleimide diphenylmethane, the conjugated diene polymer e obtained in Production Example 6; A crosslinkable rubber composition was prepared in the same manner as in Example 1 except that the rubber composition F containing 4,4′-bismaleimide diphenylmethane was used, and evaluated in the same manner. The results are shown in Table 2.

  From Tables 1 and 2, when a conjugated diene polymer having a thermoreversible bonding group is used at the end of the polymer chain, the Mooney viscosity change (difference between Compound Mooney viscosity and Polymer Mooney viscosity) In addition, the value of the Payne effect is low, and therefore, it can be determined that the processability is excellent. Further, the obtained rubber cross-linked product has good mechanical strength and also has a high breaking energy. From this, it is presumed that the chipping resistance is excellent (Examples 1 and 2).

On the other hand, when no thermoreversible bonding group was introduced at the end of the polymer chain, the value of the Payne effect was high and the processability was poor, and the resulting rubber cross-linked product had a low breaking energy. . From this, it is estimated that chipping resistance is inferior (Comparative Example 1).
In addition, when a thermoreversible linking group is introduced into the side chain instead of the polymer chain end (that is, when the main chain is modified), the introduction effect cannot be obtained, and the value of the Payne effect is high. It was inferior in processability, and the obtained rubber cross-linked product was inferior in elongation (Comparative Example 2).
Furthermore, when a silanol group is introduced instead of a thermoreversible bonding group at the polymer chain end, the value of the Payne effect is high and the processability is inferior. In addition, the breaking energy was also reduced. From this, it is speculated that the chipping resistance is inferior (Comparative Examples 3 and 4).

Claims (6)

The polymer chain end, have a thermally reversible linking group, the conjugated diene polymer represented by the following general formula (1).

(In the general formula (1), R ^{1 to} R ⁵ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and X ¹ is , —O—, —S—, —S (═O) —, —SO ₂ —, —NH—, —C (═O) —, or —OC (═O) —, and X ² is optional. (Polymer represents a polymer chain comprising a conjugated diene monomer unit.) A rubber composition comprising the conjugated diene polymer according to claim 1 and a polyfunctional thermoreversible compound. The rubber composition according to claim 2 , wherein the polyfunctional thermoreversible compound is a compound represented by the following general formula (2).

(In the general formula (2), R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and X ³ is Represents an arbitrary bonding group, and n is an integer of 2 to 10.) A crosslinkable rubber composition comprising a rubber composition according to claim 2 or 3 and a crosslinking agent. A rubber cross-linked product obtained by cross-linking the cross-linkable rubber composition according to claim 4 . A tire comprising the rubber cross-linked product according to claim 5 .