JP2008260943A - Method for producing modified polymer, modified polymer, and rubber composition using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a modified polymer that has high interaction with both silica and carbon black and gives a silica-and/or carbon black-blended rubber composition having improved breaking properties, abrasion resistance, and low heat generation properties, and also showing good processibility, and to provide the rubber composition. <P>SOLUTION: The method for obtaining the modified polymer produced by modifying a diene-based polymer comprises a process (1) to obtain a modifying agent (C) by a pretreatment of performing a reaction of a specified protonic functional group-containing compound (A) with an organo-alkali metal or alkaline earth metal compound (B) and replacing the active proton contained in the protonic functional group with the alkali metal or alkaline earth metal, a process (2) to obtain a half modified polymer by performing a reaction of the modifying agent (C) with an active part of an active part-containing polymer, and a process (3) to regenerate the active proton by disconnecting the metals from the metalated part of the obtained half modified polymer by treatment using an alcohol and/or water. The rubber composition and a tire are produced by using the modified polymer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a modified polymer, a modifier, a modified polymer, a rubber composition and a tire using the modified polymer. More specifically, the present invention is a rubber composition containing silica and / or carbon black, which enhances the interaction with silica and carbon black, and simultaneously improves fracture characteristics, wear resistance and low heat build-up, and is good The present invention relates to a method for producing a modified polymer capable of exhibiting excellent workability, a modifier, a modified polymer, and a rubber composition and a tire using the modified polymer.

In recent years, due to social demands for energy saving, demands for lower fuel consumption of automobiles are becoming more severe. In order to meet such demands, a reduction in rolling resistance has also been demanded for tire performance. As a technique for reducing the rolling resistance of a tire, a technique by optimizing the tire structure has been studied, but the most common technique is to use a material with less heat generation as a rubber composition.
In order to obtain such a rubber composition with low heat generation, many technical developments have been made so far to improve the dispersibility of the filler used in the rubber composition. Among them, a method of modifying the polymerization active site of a diene polymer obtained by anionic polymerization using a lithium compound with a functional group that interacts with a filler is becoming the most common.
The most typical of such methods is a method in which carbon black is used as a filler and a polymerization active site is modified with a tin compound (Patent Document 1). A method of introducing a group (Patent Document 2) is known.

On the other hand, in recent years, with increasing interest in safety of automobiles, not only low fuel consumption performance but also performance on wet road surfaces (hereinafter referred to as wet performance), in particular, braking performance has been increasing. For this reason, the performance requirement for the rubber composition of the tire tread is not limited to merely reducing the rolling resistance, but it is required to have a high balance between wet performance and low fuel consumption performance.
As a method for obtaining a rubber composition that gives tires such good fuel economy and good wet performance at the same time, silica is used in place of carbon black, which is a reinforcing filler generally used so far. The method is already done.

However, it has also been clarified that when silica is used as a reinforcing filler, the fracture strength and wear resistance of the rubber composition are inevitably lowered as compared with carbon black. Further, the dispersibility of silica is poor, and the workability when kneading is also a big problem in actually manufacturing a tire.
Therefore, in order to obtain a rubber composition with good exothermic properties with high productivity, not only carbon black or silica is used alone as a reinforcing filler, but also silica and carbon black are used in combination. There is a need for an active site modified polymer that has a wide interaction with the filler and can provide good dispersibility of the filler and wear resistance of the rubber composition.
However, until now, active site-modified polymers have been developed for single fillers, so that site-modified polymers with sufficient interaction with various fillers, regardless of the type of filler. Is very limited. For example, the above-mentioned tin compound has a large dispersion effect on carbon black, but has almost no dispersion effect on silica and does not exhibit a reinforcing effect at all. Moreover, although there is a report on the dispersion effect of aminosilane on silica (Patent Document 3), the effect is not always sufficient.

On the other hand, a method using an alkoxysilane having a silica dispersing effect and reinforcing effect improving effect is disclosed (Patent Document 4, Patent Document 5, Patent Document 6, etc.), but the effect is insufficient.
Further, a modified polymer in which an alkoxysilane having a dialkylamino group is introduced into the active terminal of a polymer obtained by anionic polymerization using alkyllithium or lithium amide as a polymerization initiator is disclosed (Patent Document 7). However, when this modified polymer is used, it is possible to obtain good workability, reinforcement to silica blending, and a certain dispersion effect on both silica and carpump racks, but the alkoxysilane having a dialkylamino group is expensive. Furthermore, a modified polymer using the same is also expensive and difficult to industrialize.

  By the way, the polymer having an active site used when producing a modified polymer is usually obtained by anionic polymerization of a conjugated diene compound alone or a conjugated diene compound and an aromatic vinyl compound. Introducing functional groups such as primary amino groups, secondary amino groups, and organic onium bases, which are thought to have a great effect on improving physical properties, to the active sites of polymers obtained by such anionic polymerization However, it was not easy due to the properties of anionic polymerization, and post-polymerization treatment under harsh conditions and expensive protective groups were required, and its industrial value was low.

Japanese Patent Publication No. 5-87630 JP 62-207342 A JP-A-9-151275 (2nd page) Japanese Patent Laid-Open No. 1-188501 (page 2) JP-A-8-53513 (second page) JP-A-8-53576 (2nd page) Japanese Examined Patent Publication No. 6-57767 (2nd page)

  Under such circumstances, the present invention enhances the interaction with silica and / or carbon black when used in a rubber composition containing silica and / or carbon black, and has improved destructiveness, wear resistance and low heat build-up. A method for producing a modified polymer capable of simultaneously improving and exhibiting good workability, a modified polymer obtained by this method, a rubber composition containing this modified polymer, and a tire using the rubber composition It is intended to provide.

As a result of intensive studies to achieve the above object, the present inventor, for example, a specific method capable of easily introducing a functional group having an active proton into an active site of a polymer synthesized by anionic polymerization. As a result, the present invention has been completed.
That is, the present invention relates to a method for producing a modified polymer by modifying a diene polymer, wherein (1) the general formula (I)
X ¹ −A ¹ −Y ¹ (I)
(Wherein X ¹ is a monovalent organic group having a functional group that reacts with the active site of the diene polymer, and Y ¹ is a protic function having hydrogen as an active proton bonded to nitrogen, oxygen or sulfur. A monovalent organic group having a group, and A ¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms.)
A protic functional group-containing compound (A) represented by the formula (A) is reacted with an organic alkali metal or alkaline earth metal compound (B), and the active proton in the protic functional group is converted to an alkali metal or alkaline earth metal A step of obtaining a modifying agent (C) by pretreatment, and (2) a weight for reacting the modifying agent (C) with the active site of a polymer having an organometallic active site obtained by, for example, anionic polymerization. Production of a modified polymer comprising: a step of obtaining an intermediate modified product of a coalescence; and (3) a step of releasing the metal from the metallization site of the obtained intermediate modified product to regenerate active protons. A method is provided.
The present invention also relates to a method for producing a modified polymer by modifying a diene polymer, wherein (1) the general formula (I)
X ¹ −A ¹ −Y ¹ (I)
(In the formula, X ¹ , Y ¹ and A ¹ are the same as above.)
A protic functional group-containing compound (A) represented by the formula (A) is reacted with an organic alkali metal or alkaline earth metal compound (B), and the active proton in the protic functional group is converted to an alkali metal or alkaline earth metal (2) a step of further reacting the reaction product of the pretreatment with an alkylsilyl halide to obtain a modifier (D), and (3) the modifier (D), for example, anionic polymerization A step of obtaining an intermediate modified product of the polymer to be reacted with the active site of the polymer having an organometallic active site obtained by (4), and (4) removing the metal from the metallized site of the obtained intermediate modified product. The present invention provides a method for producing a modified polymer, which comprises a step of releasing and regenerating active protons.
Furthermore, the present invention is to provide the modifying agents (C) and (D), and also provides the modified polymer, a rubber composition containing the modified polymer, and a tire using the rubber composition. Is.

  When the modified polymer in the present invention is applied to a rubber composition containing silica and / or carbon black, the interaction with silica and / or carbon black is enhanced, and the fracture characteristics, wear resistance and low heat build-up are improved. At the same time, it is possible to improve the workability. Moreover, according to the method of the present invention, the specific modified polymer having the excellent performance can be easily produced.

In the present invention, the first modifier used for the modification of the diene polymer is a reaction of a protic functional group-containing compound represented by the general formula (I) described below with an organic alkali metal or alkaline earth metal compound. Can be obtained. The second modifier is obtained by reacting the protic functional group-containing compound represented by the general formula (I) with an organic alkali metal or alkaline earth metal compound and further reacting with an alkylsilyl halide. It is done.
Here, since the second modifier is superior to the first modifier in stability over time, it is difficult to decompose, and since the reaction with the terminal active site of the polymer is easy, the second modifier is more effective than the first modifier. Preferably used.
The protic functional group-containing compound used as the raw material for the modifier must have a protic functional group and a functional group that reacts with the active site of a polymer having an organometallic active site. Therefore, the general formula (I)
X ¹ −A ¹ −Y ¹ (I)
(Wherein X ¹ is a monovalent organic group having a functional group that reacts with the active site of the diene polymer, and Y ¹ is a protic function having hydrogen as an active proton bonded to nitrogen, oxygen or sulfur. A monovalent organic group having a group, and A ¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms.)
And a protic functional group-containing compound represented by the formula:
By reacting this protic functional group-containing compound with an organic alkali metal or alkaline earth metal compound, a first modifier (C) is obtained, and this first modifier is further reacted with an alkylsilyl halide. Thus, the second modifier (D) can be obtained. As the alkylsilyl halide used for the production of the second modifier, for example, trimethylsilyl chloride is particularly preferred.

In the formula (I), as the protic functional group Y ¹ has, specifically, a primary amine and its onium salt, a secondary amine and its onium salt, a primary amide, a secondary amide, and an acetylamide , Imino, carbamoyl, (thio) carboxyl, thiol, (thio) alcohol, carboxylic acid, (thio) ureido and the like. Among these, a functional group having an active proton (hydrogen) bonded to nitrogen is more preferable.
In the modified polymer production method of the present invention, as a first step, the protic functional group-containing modifier (A) represented by the general formula (I) is treated with an organic alkali metal or alkaline earth metal compound (B). ) To react with the active protons in the Y ¹ group to be alkyl metallized or alkyl earth metallized (substituted with alkyl metal or alkyl earth metal). When this pretreatment is not performed, active protons (active hydrogen) in the protic functional group of the modifier are extracted by the active site of the polymer, so that the protic functional group is introduced into the polymer as it is. I can't.

Next, in the general formula (I), A ¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms. Examples of the divalent hydrocarbon group include an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 2 to 20 carbon atoms, an arylene group having 6 to 20 carbon atoms, and an aralkylene group having 7 to 20 carbon atoms. Among these, an alkylene group having 1 to 20 carbon atoms, particularly an alkylene group having 1 to 10 carbon atoms is preferable. The alkylene group may be linear, branched, or cyclic, but a linear one is particularly preferable. Examples of the linear alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, an octamethylene group, and a decamethylene group.
Further, X ¹ in the general formula (I) is not particularly limited as long as it is a monovalent organic group having a functional group that reacts with the active site of the polymer, but the functional group that reacts with the active site of the polymer. Examples thereof include hydrocarbyloxy group, amino group, halogen, carbonyl group, hydrocarbyloxysilyl group, halide, imine, vinyl group, amide group and the like.
X ¹ is preferably represented by formula (II)

(Wherein, R ¹ and R ² are each monovalent hydrocarbon group having 1 to 18 carbon atoms, n is an integer of 1 to 3, when R ¹ O is more, each R ¹ O is one another may be the same or different, when R ² O is more, each R ² O may be the same or different.)
The hydrocarbyloxysilyl group represented by these.
In the general formula (II), R ¹ and R ² each represent a monovalent hydrocarbon group having 1 to 18 carbon atoms. Examples of the monovalent hydrocarbon group include an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, and an aralkyl group having 7 to 18 carbon atoms. Can do. Here, the alkyl group and alkenyl group may be linear, branched or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, Isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, decyl, dodecyl, cyclopentyl, cyclohexyl, vinyl, propenyl, allyl, hexenyl, octenyl , Cyclopentenyl group, cyclohexenyl group and the like.

The aryl group may have a substituent such as a lower alkyl group on the aromatic ring, and examples thereof include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. Further, the aralkyl group may have a substituent such as a lower alkyl group on the aromatic ring, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group.
n is an integer of 1 to 3, when R ¹ O is more, each R ¹ O may be the same as or different from each other, when R ² are a plurality, each R ² is the same with or different from each other May be.

Examples of the protic functional group-containing compound represented by the general formula (I) include N-methylaminopropylmethoxysilane, N- (3-triethoxypropyl) acetamide, and trimethoxy corresponding to these triethoxysilyl compounds. Preferred examples include silyl compounds, methyldiethoxysilyl compounds, ethyldiethoxysilyl compounds, methyldimethoxysilyl compounds, and ethyldimethoxysilyl compounds. Among these, N-methylaminopropyltrimethoxysilane, N- (3 -Triethoxypropyl) acetamide is preferred.
Further, as other examples of the protic functional group-containing compound, N-hydroxyethyl-N-methylaminopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, N-5-trimethoxysilylpropyl-2-aza-1 -Oxo-caprolactam, N- (2-aminoethyl) -2-aminopropyltriethoxysilane, ureidopropyltrimethoxysilane and the like.
In the present invention, the organic lithium compound (B) used for the reaction with the protic functional group compound is the same as the lithium compound as a polymerization initiator used for polymerization of a diene polymer described later. Can be used.

Next, in the production method of the present invention, it is necessary that the preliminarily prepared modifier is reacted with the active site of the polymer synthesized by anionic polymerization. At this time, the active terminal of the polymer does not react with the lithiated protonic functional group, but reacts with the X ¹ group in the compound of the general formula (II) (modifier) to form an intermediate modified product. To do.
There is no particular limitation on the method for producing the polymer having an organometallic type active site in the molecule, and any of solution polymerization method, gas phase polymerization method and bulk polymerization method can be used. A polymerization method is preferred. Moreover, any of a batch type and a continuous type may be sufficient as the superposition | polymerization form.

The metal of the active site is preferably one selected from alkali metals and alkaline earth metals, and lithium metal is particularly preferable.
In the solution polymerization method, for example, the target polymer can be produced by anionic polymerization of a diene compound alone or a diene compound and an aromatic vinyl compound using a lithium compound as a polymerization initiator.
The active site may be present in the polymer molecule, and is not particularly limited. However, when the polymer is based on anionic polymerization using an alkali metal compound and / or an alkaline earth metal compound as a polymerization initiator. In general, the active site is at the end of the polymer.

The diene compound is preferably a conjugated diene compound, such as 1,3-butadiene; isoprene; 1,3-pentadiene; 2,3-dimethylbutadiene; 2-phenyl-1,3-butadiene; 1,3-hexadiene and the like. Is mentioned. These may be used alone or in combination of two or more, and among these, 1,3-butadiene and isoprene are particularly preferable.
Examples of the aromatic vinyl compound used for copolymerization with these conjugated diene compounds include styrene; α-methylstyrene; 1-vinylnaphthalene; 3-vinyltoluene; ethylvinylbenzene; divinylbenzene; 4-cyclohexylstyrene. 2,4,6-trimethylstyrene and the like. These may be used alone or in combination of two or more, but among these, styrene is particularly preferred.

Furthermore, when copolymerization is performed using a conjugated diene compound and an aromatic vinyl compound as monomers, the use of 1,3-butadiene and styrene, respectively, in terms of practicality such as the availability of monomers, And anionic polymerization characteristics are particularly preferred in view of the living property.
When the solution polymerization method is used, the monomer concentration in the solvent is preferably 5 to 50% by weight, more preferably 10 to 30% by weight. When copolymerization is performed using a conjugated diene compound and an aromatic vinyl compound, the content of the aromatic vinyl compound in the charged monomer mixture is preferably 3 to 50% by weight, more preferably 5 to 45% by weight. Is preferred.

The lithium compound of the polymerization initiator is not particularly limited, but hydrocarbyl lithium and lithium amide compounds are preferably used. When the former hydrocarbyl lithium is used, it has a hydrocarbyl group at the polymerization initiation terminal and the other terminal. A conjugated diene polymer having a polymerization active site is obtained. When the latter lithium amide compound is used, a conjugated diene polymer having a nitrogen-containing group at the polymerization initiation terminal and the other terminal being a polymerization active site is obtained.
As the hydrocarbyl lithium, those having a hydrocarbyl group having 2 to 20 carbon atoms are preferable, for example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-octyl lithium, n-decyl. Examples include lithium, phenyl lithium, 2-naphthyl lithium, 2-butyl-phenyl lithium, 4-phenyl-butyl lithium, cyclohexyl lithium, cyclopentyl lithium, reaction products of diisopropenylbenzene and butyl lithium, and the like. Of these, n-butyllithium is preferred.

  On the other hand, as the lithium amide compound, for example, lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene imide, lithium dodecamethylene imide, lithium dimethyl amide, lithium diethyl amide, lithium dibutyl amide, lithium dipropyl amide, lithium Diheptylamide, lithium dihexylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium-N-methylpiperazide, lithium ethylpropylamide, lithium ethylbutyramide, lithium methylbutyramide, lithium ethylbenzylamide, Examples include lithium methyl phenethyl amide. Among these, cyclic lithium amides such as lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene imide, and lithium dodecamethylene imide are preferable from the viewpoint of the interaction effect on carbon black and the ability to initiate polymerization. Particularly preferred are lithium hexamethylene imide and lithium pyrrolidide.

These lithium amide compounds are generally prepared in advance from a secondary amine and a lithium compound for polymerization, but can also be prepared in a polymerization system (in-situ). The amount of the polymerization initiator used is preferably selected in the range of 0.2 to 20 mmol per 100 g of monomer.
There is no restriction | limiting in particular as a method of manufacturing a conjugated diene polymer by anionic polymerization using the said lithium compound as a polymerization initiator, A conventionally well-known method can be used.
Specifically, in an organic solvent inert to the reaction, for example, a hydrocarbon solvent such as an aliphatic, alicyclic or aromatic hydrocarbon compound, the conjugated diene compound or the conjugated diene compound and the aromatic vinyl compound are The desired conjugated diene polymer can be obtained by anionic polymerization using a lithium compound as a polymerization initiator in the presence of a randomizer to be used, if desired.

The hydrocarbon solvent is preferably one having 3 to 8 carbon atoms, such as propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene and trans-2. -Butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene and the like. These may be used alone or in combination of two or more.
The randomizer used as desired is a control of the microstructure of the conjugated diene polymer, such as an increase in 1,2 bonds in the butadiene moiety in the butadiene-styrene copolymer, an increase in 3,4 bonds in the isoprene polymer, or the like. It is a compound having an effect of controlling the composition distribution of monomer units in a conjugated diene compound-aromatic vinyl compound copolymer, for example, randomizing butadiene units and styrene units in a butadiene-styrene copolymer. The randomizer is not particularly limited, and any one of known compounds generally used as a conventional randomizer can be appropriately selected and used. Specifically, dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, bistetrahydrofurylpropane, triethylamine, pyridine, N-methylmorpholine, N, N, N ′, N′-tetramethylethylenediamine, 1, Examples include ethers such as 2-dipiperidinoethane and tertiary amines. Further, potassium salts such as potassium-t-amylate and potassium-t-butoxide, and sodium salts such as sodium-t-amylate can also be used.
One of these randomizers may be used alone, or two or more thereof may be used in combination. The amount used is preferably selected in the range of 0.01 to 1000 molar equivalents per mole of the lithium compound.

The temperature in this polymerization reaction is preferably selected in the range of 0 to 150 ° C, more preferably 20 to 130 ° C. The polymerization reaction can be carried out under generated pressure, but it is usually desirable to operate at a pressure sufficient to keep the monomer in a substantially liquid phase. That is, the pressure depends on the particular material being polymerized, the polymerization medium used and the polymerization temperature, but higher pressures can be used if desired, such pressure being a gas that is inert with respect to the polymerization reaction. Can be obtained by an appropriate method such as pressurizing.
In this polymerization, it is desirable that all raw materials involved in the polymerization, such as a polymerization initiator, a solvent, and a monomer, are obtained by removing reaction inhibitors such as water, oxygen, carbon dioxide, and protic compounds.
In addition, when obtaining a polymer as an elastomer, it is preferable that the glass transition point (Tg) calculated | required by the differential thermal analysis method of the polymer or copolymer obtained is -90 degreeC--15 degreeC. It is difficult to obtain a polymer having a glass transition point of less than −90 ° C., and when it exceeds −15 ° C., the viscosity becomes too high in the room temperature region, which may make handling difficult.

In the present invention, the modifying agent is reacted with the obtained polymer having an organometallic active site in the molecule, preferably by adding a stoichiometric amount or an excess of the active site.
The intermediate modified polymer thus obtained needs to regenerate active protons by removing lithium from the lithiation site in the final step. Such active protons can be easily regenerated by, for example, treatment with alcohol or water. At the same time, the active protons are regenerated in the intermediate modified polymer in the normal solvent removal and steam stripping steps in the drying process. be able to.
In the present invention, a modified polymer can be produced by the above-described method. The modified polymer of the present invention is exemplified below using N-methylaminopropyltrimethoxysilane (MAPMOS) as a modifier. The reaction mechanism in the method for producing the coalescence will be described.

In the above, first, when butyl lithium (BuLi) is allowed to act on MAPMOS, the active proton of the amino group in MAPMOS is extracted by Bu anion to become MAPMOS lithium salt (A ′), and then the lithium salt (A After reacting ') with the active terminal of the polymer (M ⁺ is an active metal), the amino group having active protons is regenerated by reacting with water or the like. The modified polymer in the present invention is obtained by such a reaction mechanism.
In the present invention, in this modification reaction, if desired, a known anti-aging agent or a short stop agent for the purpose of terminating the polymerization reaction, and a step after introducing a compound residue of the modifier in the active site of the polymer. , Can be added.
After the modification treatment in this way, a conventionally known post-treatment such as solvent removal can be performed to obtain the desired modified polymer. Analysis of the polymer chain active site modification group of this modified polymer can be performed using high performance liquid chromatography (HPLC) or nuclear magnetic resonance spectroscopy (NMR).

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the modified polymer is preferably 10 to 150, more preferably 15 to 80. When the Mooney viscosity is less than 10, sufficient rubber properties such as fracture characteristics cannot be obtained, and when it exceeds 150, workability is poor and it is difficult to knead with the compounding agent.
In the present invention, the modified polymer obtained in this way has an active proton at the terminal, so when carbon black is blended with this, hydrogen bonds with the functional group on the surface of the carbon black, Its dispersibility and reinforcement can be greatly increased. Moreover, when a modifier has the hydrocarbyl oxysilane compound residue represented, for example by the said general formula (II), the affinity with a silica is also large simultaneously.
Therefore, when the modified polymer in the present invention is applied to a rubber composition containing silica and / or carbon black, the interaction with silica and / or carbon black is enhanced, and fracture characteristics, abrasion resistance and It is possible to obtain a modified polymer that can improve low heat build-up at the same time and can exhibit good workability, and a rubber composition and a tire using the modified polymer.
Therefore, the present invention comprises a modified polymer containing a protic functional group having hydrogen as an active proton bonded to nitrogen, oxygen or sulfur at the terminal site of a conjugated diene polymer synthesized by anionic polymerization. But there is.

Next, the rubber composition of the present invention contains the above-mentioned modified polymer. Usually, a rubber component containing at least 30% by weight of the modified polymer and 100 parts by weight of silica and / or carbon black. A rubber composition containing 10 to 100 parts by weight is preferred.
This modified polymer may be used alone or in combination of two or more. The rubber component used in combination with the modified polymer includes natural rubber and diene synthetic rubber. Examples of the diene synthetic rubber include styrene-butadiene copolymer (SBR), polybutadiene (BR), poly Examples include isoprene (IR), butyl rubber (IIR), ethylene-propylene copolymer, and mixtures thereof. Further, a part thereof may have a branched structure by using a polyfunctional modifier, for example, a modifier such as tin tetrachloride.

The silica is not particularly limited, and can be arbitrarily selected from those conventionally used as reinforcing fillers for rubber.
Examples of the silica include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and the like. Wet silica that is noticeable is preferred. On the other hand, the carbon black is not particularly limited, and any carbon black conventionally used as a reinforcing filler for rubber can be selected and used. Examples of the carbon black include FEF, SRF, HAF, ISAF, and SAF. Carbon black having an iodine adsorption amount (IA) of 60 mg / g or more and a dibutyl phthalate oil absorption (DBP) of 80 ml / 100 g or more is preferable. By using this carbon black, the effect of improving various physical properties is increased, but HAF, ISAF, and SAF, which are excellent in wear resistance, are particularly preferable.

  In the rubber composition of the present invention, when silica is used as the reinforcing filler, a silane coupling agent can be blended for the purpose of further improving the reinforcing property. Examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, and bis (2-triethoxy). Silylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyl Trimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthioca Bamoylchitrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxy Silylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyltetra Sulfide, dimethoxymethylsilylpropyl benzothiazole tetrasulfide, etc. are mentioned, but from these points, such as reinforcing effect improvement effect, Scan (3-triethoxysilylpropyl) tetrasulfide and 3-trimethoxysilylpropyl benzothiazolyl tetrasulfide are preferable. These silane coupling agents may be used singly or in combination of two or more.

The blending amount of the preferred silane coupling agent varies depending on the type of the silane coupling agent, but is preferably selected in the range of 1 to 20% by weight with respect to silica. If this amount is less than 1% by weight, the effect as a coupling agent is hardly exhibited, and if it exceeds 20% by weight, the rubber component may be gelled. From the viewpoint of the effect as a coupling agent and the prevention of gelation, the preferred amount of the silane coupling agent is in the range of 5 to 15% by weight.
In the rubber composition of the present invention, various chemicals usually used in the rubber industry, for example, vulcanizing agents, vulcanization accelerators, process oils, anti-aging agents, as long as the object of the present invention is not impaired. A scorch inhibitor, zinc white, stearic acid and the like can be contained.

The rubber composition of the present invention is obtained by kneading using a kneading machine such as a roll or an internal mixer, and is vulcanized after molding, starting with tire applications, anti-vibration rubber, belt, hose. It can also be used for other industrial products. In particular, it is suitably used as tire rubber, and can be applied to all tire members such as tread rubber (including cap rubber and base rubber), side rubber, ply rubber, and bead filler rubber.
In the present invention, a tire using a rubber composition has good fuel efficiency, particularly excellent fracture characteristics and wear resistance, and the processability of the rubber composition is good. Also excellent.

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

<Physical properties of polymer>
The weight average molecular weight (Mw) of the (modified) polymer was measured by gel permeation chromatography [GPC: Tosoh HLC-8020, column: Tosoh GMH-XL (two in series)] Using the differential refractive index (RI), the measurement was performed in terms of polystyrene using monodisperse polystyrene as a standard.
The vinyl content in the butadiene portion of the polymer was determined by the infrared method, and the styrene unit content in the polymer was calculated from the integral ratio of the ¹ H-NMR spectrum.
The Mooney viscosity of the polymer was measured at 100 ° C. using an RLM-01 type tester manufactured by Toyo Seiki Co., Ltd.

<Physical properties of vulcanized rubber>
(1) Low exothermic property Using a viscoelasticity measuring device (manufactured by Rheometrics), tan δ (50 ° C.) was measured at a temperature of 50 ° C., a strain of 10%, and a frequency of 15 Hz. The smaller tan δ (50 ° C.), the lower the heat generation.
(2) Fracture characteristics (tensile strength)
The strength (T _b ) at the time of cutting was measured according to JIS K6301-1995.
(3) Abrasion resistance Using a Ramborn-type abrasion tester, the amount of wear at a slip rate of 60% at room temperature was measured, and the abrasion resistance of Comparative Example 4 was shown as an index. The larger the index, the better.

<Mooney viscosity of rubber composition>
The Mooney viscosity [ML _{1 +} 4/130 ° C.] was measured at 130 ° C. according to JIS K6300-1994.

Example 1
(1) Preparation of denaturant solution Prepare a 1N cyclohexane solution of N-methylaminopropyltrimethoxysilane (MAPMOS) in a 300 ml pressure-resistant glass container that has been dried and purged with nitrogen so that it is equivalent to MAPMOS. Then, a 3.65N cyclohexane solution of n-butyllithium (BuLi) was added dropwise and stirred well to prepare a solution of the modifier (C).
(2) Production of modified polymer In a dry, nitrogen-substituted 800 ml pressure-resistant glass container, cyclohexane 300 g, 1,3-butadiene monomer 40 g, styrene monomer 10 g, ditetrahydrofurylpropane 0.43 mmol Was added and 0.48 mmol of n-butyllithium (BuLi) was added thereto, followed by polymerization at 50 ° C. for 1.5 hours. The polymerization conversion was almost 100%.
To this polymerization system, the solution of the modifying agent (C) prepared in (1) was added so that N-methylaminopropyltrimethoxysilane was 0.43 mmol, and then a modification reaction was performed at 50 ° C. for 30 minutes. Thereafter, 0.5 ml of a 5 wt% solution of 2,6-di-t-butyl-p-cresol (BHT) in isopropanol was added to stop the reaction, and then the solvent was removed by steam stripping according to a conventional method. Drying was performed to obtain a modified polymer D. The analytical values of the obtained polymer are shown in Table 1.

Example 2 and Comparative Examples 1 and 2
Example 1 (1) In the preparation of the modifier solution, the same procedure as in Example 1 was used except that the modifier of the type shown in Table 1 was used instead of the modifier N-methylaminopropyltrimethoxysilane. Thus, polymers A, B (comparative examples) and E (examples) were obtained. The analytical value of each polymer obtained is shown in Table 1.
Comparative Example 3
In Example 1, the polymer solution C was used in the same manner as in Example 1 except that the modifier solution was not used and (2) in the production of the modified polymer, the amount of BuLi added was 0.38 mmol. Got. The analytical values of the obtained polymer are shown in Table 1.
Example 3
(1) Preparation of denaturant solution Prepare a 1N cyclohexane solution of N-methylaminopropyltrimethoxysilane (MAPMOS) in a 300 ml pressure-resistant glass container that has been dried and purged with nitrogen so that it is equivalent to MAPMOS. After adding a 3.65N cyclohexane solution of n-butyllithium (BuLi) dropwise, a 1N cyclohexane solution of trimethylsilyl chloride (TMSCL) was prepared, added to an equivalent amount to MAPMOS, and stirred well, A solution of denaturant (D) was prepared.
(2) Production of modified polymer The production of the modified polymer of Example 1 was carried out in the same manner as in Example 1 except that the solution of the modifier (D) prepared in (1) was added to the polymerization system. The polymer F was obtained. The analytical values of the obtained polymer are shown in Table 1.
Example 4
Example 1 (1) In the preparation of the modifier solution, the same procedure as in Example 1 was used except that 3-mercaptopropyltriethoxysilane was used instead of the modifier N-methylaminopropyltrimethoxysilane. Thus, a polymer G was obtained. The analytical value of each polymer obtained is shown in Table 1.

(note)
Base Mw: weight average molecular weight (Mw) before denaturation reaction
Total Mw: weight average molecular weight (Mw) after the denaturation reaction
Modifier (Comparative Example 1) TTC; Tin Tetrachloride (Comparative Example 2) TEOS; Tetraethoxysilane (Example 1) MAPMOS; N-methylaminopropyltrimethoxysilane to which BuLi was added in an equivalent amount (Example 2) TEOSAA; BuLi N- (3-triethoxysilylpropyl) acetamide added with an equivalent amount (Example 3) MAPMOS &TMCL; N-methylaminopropyltrimethoxysilane added with an equivalent amount of BuLi and trimethylsilyl chloride were reacted (Example 4) MrPTEOS; BuLi 3-mercaptopropyltriethoxysilane added with an equivalent amount of

Examples 5 to 8 and Comparative Examples 4 to 6 (rubber compositions)
Using the polymers A to G obtained in Examples 1 to 4 and Comparative Examples 1 to 3, according to the formulation 1 and the formulation 2 shown in Table 2, the rubber composition of the silica-based formulation and the rubber of the carbon black-based formulation, respectively The composition was prepared by the following method, and the Mooney viscosity of the rubber composition was measured, and vulcanized at 160 ° C. for 15 minutes, and the physical properties of the vulcanized rubber were measured. The results are shown in Table 3.

(note)
Carbon black: “Seast KH (N339) (trademark)” manufactured by Tokai Carbon Co., Ltd.
Silica: “Nipsil AQ (trademark)” manufactured by Nippon Silica Kogyo Co., Ltd.
Coupling agent: Degussa silane coupling agent “Si69 (trademark)”, bis (3-triethoxysilylpropyl) tetrasulfide anti-aging agent 6C; N- (1,3-dimethylbutyl) -N′-phenyl- p-phenylenediamine vulcanization accelerator DPG; diphenylguanidine vulcanization accelerator DM; mercaptobenzothiazyl disulfide vulcanization accelerator NS; Nt-butyl-2-benzothiazylsulfenamide

  As a result of the above, the modified polymer of the present invention remarkably improves low heat buildup and wear resistance without suppressing the increase in Mooney viscosity and impairing fracture characteristics in both silica-based and carbon black-based formulations. It is recognized that

Claims (18)

In the method for producing a modified polymer by modifying a diene polymer, (1) General formula (I)
X ¹ −A ¹ −Y ¹ (I)
(Wherein X ¹ is a monovalent group having a functional group that reacts with the active site of the diene polymer, and Y ¹ is a protic functional group having hydrogen as an active proton bonded to nitrogen, oxygen, or sulfur. (In addition, A ¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms.)
A protic functional group-containing compound (A) represented by the formula (A) is reacted with an organic alkali metal or alkaline earth metal compound (B), and the active proton in the protic functional group is converted to an alkali metal or alkaline earth metal A step of obtaining a modifier (C) by pretreatment, and a step of (2) obtaining an intermediate modified product of a polymer obtained by reacting the modifier (C) with the active site of a polymer having an active site; 3) Production of a modified polymer comprising a step of removing the metal from the metallization site of the intermediate modified product obtained by treatment with alcohol and / or water to regenerate active protons. Method. In the method for producing a modified polymer by modifying a diene polymer, (1) General formula (I)
X ¹ −A ¹ −Y ¹ (I)
(Wherein X ¹ is a monovalent group having a functional group that reacts with the active site of the diene polymer, and Y ¹ is a protic functional group having hydrogen as an active proton bonded to nitrogen, oxygen, or sulfur. (In addition, A ¹ is a divalent hydrocarbon group having 1 to 20 carbon atoms.)
A protic functional group-containing compound (A) represented by the formula (A) is reacted with an organic alkali metal or alkaline earth metal compound (B), and the active proton in the protic functional group is converted to an alkali metal or alkaline earth metal (2) a step of obtaining a modifier (D) by further reacting the reaction product of the preliminary treatment with an alkylsilyl halide, and (3) the modifier (D) with an active site. A step of obtaining an intermediate modified product of the polymer to be reacted with the active site of the polymer having a hydrogen atom, and (4) treatment with alcohol and / or water to obtain the metal from the metallized site of the obtained intermediate modified product. A method for producing a modified polymer, comprising the step of releasing active protons to regenerate active protons.   The monovalent group having a functional group that reacts with the active site of the diene polymer is selected from hydrocarbyloxysilyl group, carbonyl group, halide, imine, vinyl group, amide group, hydrocarbyloxy group, amino group, and halogen. The method for producing a modified polymer according to claim 1, which is at least one kind.   The protic functional group includes a primary amine and its onium salt, a secondary amine and its onium salt, a primary amide, a secondary amide and a (thio) carboxyl group, a mercapto group, a (thio) alcohol and ( The method for producing a modified polymer according to any one of claims 1 to 3, which is at least one functional group selected from the group of thio) ureido.   The protonic functional group-containing compound is a triethoxysilyl compound, a trimethoxysilyl compound, a methyldiethoxysilyl compound, an ethyldiethoxysilyl compound, a methyldimethoxysilyl compound, or an ethyldimethoxysilyl compound. A method for producing the modified polymer according to 1.   The diene polymer is a polymer obtained by homopolymerizing a conjugated diene compound or by copolymerizing a conjugated diene compound and another monomer. A method for producing the modified polymer as described.   The method for producing a modified polymer according to any one of claims 1 to 6, wherein the metal at the active site of the diene polymer is at least one selected from alkali metals and alkaline earth metals.   The method for producing a modified polymer according to any one of claims 1 to 7, wherein the other monomer is an aromatic vinyl compound.   The method for producing a modified polymer according to any one of claims 1 to 8, wherein the active site is at the end of the polymer and at least a part thereof is in an active state.   10. A polymer having an organometallic active site in a molecule is reacted with a protic functional group-containing modifier added in an approximately stoichiometric amount or an excess amount to the active site. A method for producing a modified polymer according to any one of the above.   The method for producing a modified polymer according to claim 6, wherein the conjugated diene compound is 1,3-butadiene or isoprene.   The method for producing a modified polymer according to claim 8, wherein the aromatic vinyl compound is styrene.   A modified polymer obtained by the production method according to claim 1. The modified polymer according to claim 13, having a Mooney viscosity (ML _{1 +} 4/100 ° C) of 10 to 150.   A rubber composition comprising the modified polymer according to claim 13 or 14.   The rubber composition according to claim 15, comprising a rubber component containing at least 20% by weight of the modified polymer according to claim 13 or 14, and 10 to 100 parts by weight of silica and / or carbon black per 100 parts by weight thereof.   The rubber composition according to claim 16, comprising 0 to 20% by weight of a silane coupling agent relative to silica.   A tire comprising the rubber composition according to claim 15, 16 or 17.