JP6068020B2 - Method for producing rubber composition - Google Patents

Description

  The present invention relates to a method for producing a rubber composition, and particularly relates to a method for producing a rubber composition having improved durability, such as tear resistance, while maintaining high wear resistance and low heat build-up. The present invention relates to a high-performance tire obtained by use.

In recent years, tires with low rolling resistance have been demanded in order to save fuel consumption of automobiles under the social demand for energy saving and resource saving. In response to such demands, as a method of reducing the rolling resistance of the tire, by reducing the amount of carbon black used or by using lower carbon black, a rubber composition having a reduced hysteresis loss can be used as a tire member, In particular, a method used for tread rubber is known. Also, rolling resistance can be improved by increasing the proportion of the high cis polybutadiene rubber in the rubber component and increasing the elasticity of the rubber composition.
For example, Patent Document 1 discloses a rubber composition using a modified polymer such as a terminal-modified polybutadiene rubber. By improving the dispersibility of carbon black, both the wear resistance and rolling resistance of the tire can be achieved. I am trying.

  However, if the amount of carbon black to be used is simply reduced as in the prior art, there is a possibility that the wear resistance of the rubber composition is reduced. In addition, when specializing in increasing the proportion of the polybutadiene rubber in the rubber component and increasing the elasticity of the rubber composition, there arises a problem that durability including the tear resistance of the rubber composition is lowered. On the other hand, according to the rubber composition disclosed in Patent Document 1, the hysteresis loss of terminal-modified polybutadiene is reduced, and a certain effect is obtained with respect to wear resistance and rolling resistance. There is still room for improvement from the viewpoint of further improving the performance.

JP-A-2005-041975

  Under such circumstances, the present invention provides a method for producing a rubber composition capable of reducing rolling resistance while improving durability such as wear resistance and tear resistance, and also provides such a rubber composition. It is an object to provide a tire in which the wear resistance, tear resistance and rolling resistance used are highly balanced.

［式中、複数あるＲ¹は、それぞれ独立して炭素数１〜１２のアルキル基、シクロアルキル基又はアラルキル基である。］で表される置換アミノ基、及び下記式(II)：

［式中、Ｒ²は、３〜１６のメチレン基を有するアルキレン基、置換アルキレン基、オキシアルキレン基又はＮ-アルキルアミノ-アルキレン基を示す。］で表される環状アミノ基からなる群から選択される上記［２］のゴム組成物の製造方法、
［４］ 前記窒素含有官能基が、ヘキサメチレンイミノ基である上記［３］のゴム組成物の製造方法、
［５］ 前記共役ジエン系重合体が、ポリブタジエンゴムである上記［１］〜［４］のいずれかのゴム組成物の製造方法、
［６］ 前記混練の第二段階のゴム組成物の最高温度が１５０℃以上である上記［１］〜［５］のいずれかのゴム組成物の製造方法、
［７］ 前記ゴム成分（Ａ）１００質量部に対し、前記ヒドラジド化合物（Ｃ）の少なくとも１種を０．２〜３質量部含有する上記［１］〜［６］のいずれかのゴム組成物の製造方法、
［８］ 前記ヒドラジド化合物（Ｃ）が、−Ｃ（＝Ｏ）ＮＨＮ＝Ｃ（Ｒ^a）Ｒ^bで表されるヒドラジド基を少なくとも１以上含む化合物である上記［１］〜［７］のいずれかのゴム組成物の製造方法、
［但し、式中のＲ^a及びＲ^bは、水素原子又は炭素数１〜１８の範囲にあるＯ、Ｓ、及びＮの元素を含んでよい環状又は非環状の炭化水素基であり、それぞれ独立していてもよいし、Ｒ^a及びＲ^bが結合して環状の炭化水素基を形成していてもよい。］
［９］ 前記ヒドラジド化合物（Ｃ）が、一般式（III）で表されるヒドラジド化合物である上記［８］のゴム組成物の製造方法、

［式中、Ｒ³及びＲ⁴は、それぞれ独立して水素原子又は炭素数１〜１８の炭化水素基を示し、Ｒ³とＲ⁴は互いに結合して環構造を形成していてもよい。］
［１０］ 前記充填材（Ｂ）が、カーボンブラック及び／又はシリカである上記［１］〜［９］いずれかのゴム組成物の製造方法、
［１１］ 前記天然ゴムと少なくとも一種の窒素含有官能基を有する変性共役ジエン系重合体とを含むゴム成分（Ａ）１００質量部に対して、前記カーボンブラック３０質量部〜６０質量部及び前記シリカ０．５〜１５質量部を含有する上記［１］〜［１０］のいずれかのゴム組成物の製造方法、
［１２］ 前記ゴム組成物が、さらに、質量比［シランカップリング剤／前記シリカ］として（１／１００）〜（２０／１００）のシランカップリング剤を含有する上記［１０］又は［１１］のゴム組成物の製造方法、
［１３］ 上記［１］〜［１２］のいずれかのゴム組成物の製造法により得られたゴム組成物、及び
［１４］ 上記［１３］のゴム組成物をタイヤ部材に用いたタイヤ、
を提供するものである。 In order to solve the above problems, the present inventor kneaded natural rubber, a rubber component (A) containing a modified conjugated diene polymer having at least one nitrogen-containing functional group, and at least one filler (B). A first stage of kneading, a second stage of kneading the hydrazide compound (C) to the rubber composition obtained by the first stage of kneading, and a rubber composition obtained by the second stage of kneading. It was found that the above-mentioned problems can be achieved by kneading the vulcanizing agent and the vulcanization accelerator in at least three stages of the final stage of kneading, and the present invention has been completed.
That is, the present invention
[1] A first stage of kneading in which a rubber component (A) containing natural rubber and a modified conjugated diene polymer having at least one nitrogen-containing functional group and at least one filler (B) are kneaded, and the kneading A second stage of kneading the hydrazide compound (C) to the rubber composition obtained by the first stage, and a vulcanizing agent and a vulcanization accelerator to the rubber composition obtained by the second stage of the kneading. A method for producing a rubber composition, characterized by comprising kneading and a final stage of kneading,
[2] The method for producing a rubber composition according to [1], wherein the nitrogen-containing functional group is a substituted or unsubstituted amino group, amide group, imino group, imidazole group, nitrile group, or pyridyl group,
[3] The nitrogen-containing functional group has the following formula (I):

[Wherein, a plurality of R ¹ are each independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, or an aralkyl group. And a substituted amino group represented by the following formula (II):

[Wherein, R ² represents an alkylene group having 3 to 16 methylene groups, a substituted alkylene group, an oxyalkylene group or an N-alkylamino-alkylene group. ] The manufacturing method of the rubber composition of said [2] selected from the group which consists of cyclic amino group represented by these,
[4] The method for producing a rubber composition according to [3], wherein the nitrogen-containing functional group is a hexamethyleneimino group,
[5] The method for producing a rubber composition according to any one of the above [1] to [4], wherein the conjugated diene polymer is a polybutadiene rubber.
[6] The method for producing a rubber composition according to any one of the above [1] to [5], wherein the maximum temperature of the rubber composition in the second stage of the kneading is 150 ° C. or higher.
[7] The rubber composition according to any one of [1] to [6], wherein 0.2 to 3 parts by mass of at least one hydrazide compound (C) is contained with respect to 100 parts by mass of the rubber component (A). Manufacturing method,
[8] Any of [1] to [7] above, wherein the hydrazide compound (C) is a compound containing at least one hydrazide group represented by —C (═O) NHN═C (R ^a ) R ^b. A method for producing the rubber composition,
[However, R ^a and R ^b in the formula are a hydrogen atom or a cyclic or non-cyclic hydrocarbon group which may contain O, S, and N elements having 1 to 18 carbon atoms, each independently. R ^a and R ^b may combine to form a cyclic hydrocarbon group. ]
[9] The method for producing a rubber composition according to [8], wherein the hydrazide compound (C) is a hydrazide compound represented by the general formula (III),

[Wherein, R ³ and R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and R ³ and R ⁴ may be bonded to each other to form a ring structure. ]
[10] The method for producing a rubber composition according to any one of the above [1] to [9], wherein the filler (B) is carbon black and / or silica,
[11] 30 parts by mass to 60 parts by mass of the carbon black and the silica with respect to 100 parts by mass of the rubber component (A) containing the natural rubber and the modified conjugated diene polymer having at least one nitrogen-containing functional group. A method for producing a rubber composition according to any one of the above [1] to [10], comprising 0.5 to 15 parts by mass,
[12] The above [10] or [11], wherein the rubber composition further contains a silane coupling agent of (1/100) to (20/100) as a mass ratio [silane coupling agent / silica]. A method for producing a rubber composition of
[13] A rubber composition obtained by the method for producing a rubber composition according to any one of [1] to [12], and [14] a tire using the rubber composition according to [13] as a tire member,
Is to provide.

  According to the present invention, a method for producing a rubber composition capable of reducing rolling resistance while improving durability such as wear resistance and tear resistance, and wear resistance using such a rubber composition. It is possible to provide a tire that is highly balanced in performance, tear resistance, and rolling resistance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional front view of an example of a carbon black production furnace for producing carbon black used in a method for producing a rubber composition of the present invention.

The present invention is described in detail below.
The method for producing the rubber composition of the present invention comprises kneading a rubber component (A) containing natural rubber and at least one modified conjugated diene polymer having a nitrogen-containing functional group and at least one filler (B). A first stage of kneading, a second stage of kneading the hydrazide compound (C) to the rubber composition obtained by the first stage of kneading, and a rubber composition obtained by the second stage of kneading. And a kneading step of kneading a vulcanizing agent and a vulcanization accelerator.

In the present invention, the rubber component (A) containing natural rubber and at least one modified conjugated diene polymer having a nitrogen-containing functional group and at least one filler (B) are kneaded to obtain the first step. In the rubber composition, the polymer terminal having a nitrogen-containing functional group and the filler (B) are effectively bonded, and the dispersion of the filler (B) (carbon and / or silica) in the polymer is improved. A rubber composition excellent in exothermic property (low tan δ) can be obtained. The rubber composition obtained in the first stage of kneading is kneaded with the hydrazide compound (C) and further reacted with the hydrazide compound (C), thereby improving the reinforcement between the polymer fillers, which is an object of the present invention. It is possible to provide a method for producing a rubber composition capable of reducing rolling resistance while improving durability such as wear resistance and tear resistance.
In order to obtain a rubber composition having the above performance, the maximum temperature in the second stage of the kneading is preferably 150 ° C. or higher. Although there is no restriction | limiting in particular about the upper limit, It is more preferable that the maximum temperature of the said 2nd step of the said kneading | mixing is 150-190 degreeC.
Further, as described above, the functional group of the modified conjugated diene polymer is preferably a nitrogen-containing functional group, and effectively binds to carbon black, silica, or the like as the filler (B).
The maximum temperature of the rubber composition in the first stage of kneading is preferably 120 to 190 ° C, more preferably 150 to 190 ° C. The maximum temperature of the rubber composition at the final stage of kneading, in which the vulcanizing agent and vulcanization accelerator are kneaded, is preferably 100 ° C to 120 ° C, more preferably 100 ° C to 110 ° C.

[Nitrogen-containing functional group]
In the method for producing a rubber composition of the present invention, the nitrogen-containing functional group of the modified conjugated diene polymer is preferably a substituted or unsubstituted amino group, amide group, imino group, imidazole group, nitrile group, and pyridyl group. The following formula (I):

［式中、複数あるＲ¹は、それぞれ独立して炭素数１〜１２のアルキル基、シクロアルキル基又はアラルキル基である。］で表される置換アミノ基、及び下記式(II)：

[Wherein, a plurality of R ¹ are each independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, or an aralkyl group. And a substituted amino group represented by the following formula (II):

［式中、Ｒ²は、３〜１６のメチレン基を有するアルキレン基、置換アルキレン基、オキシアルキレン基又はＮ-アルキルアミノ-アルキレン基を示す。］で表される環状アミノ基からなる群から選択される官能基が更に好ましく、ヘキサメチレンイミノ基が特に好ましい。これらの窒素含有官能基は、カーボンブラック、シリカ等の種々の充填剤を配合したゴム組成物において充填剤分散効果が高く、充填剤の補強効果を大幅に向上できる。

[Wherein, R ² represents an alkylene group having 3 to 16 methylene groups, a substituted alkylene group, an oxyalkylene group or an N-alkylamino-alkylene group. A functional group selected from the group consisting of cyclic amino groups represented by the formula: is more preferred, and a hexamethyleneimino group is particularly preferred. These nitrogen-containing functional groups have a high filler dispersion effect in a rubber composition containing various fillers such as carbon black and silica, and can greatly improve the reinforcing effect of the filler.

(Modified conjugated diene polymer having a nitrogen-containing functional group)
In another preferred embodiment of the method for producing a rubber composition of the present invention, the conjugated diene polymer is a polybutadiene rubber, particularly preferably a polybutadiene rubber having at least one hexamethyleneimino group.
In the rubber composition in which the carbon component is blended with the rubber component (A) containing the modified conjugated diene polymer having a nitrogen-containing functional group used in the present invention, the dispersibility of the carbon black with respect to the rubber component (A) is high. Thus, since the hysteresis loss of the rubber component (A) is reduced, the wear resistance and rolling resistance can be improved.

  In the composition used in the present invention, the modified conjugated diene polymer used for the rubber component (A) is not particularly limited as long as it has at least one nitrogen-containing functional group, and is compatible with fillers such as carbon black and silica. Other functional groups generally known to have properties such as silicon-containing functional groups or tin-containing functional groups may be included. Here, as the conjugated diene polymer, a copolymer of a conjugated diene compound and an aromatic vinyl compound and a homopolymer of a conjugated diene compound are preferable. Specifically, polyisoprene rubber (IR), styrene- Butadiene copolymer rubber (SBR), polybutadiene rubber (BR), isobutylene isoprene rubber (butyl rubber: IIR), halogenated butyl rubber, styrene-isoprene copolymer rubber (SIR), ethylene-butadiene copolymer rubber (EBR), Synthetic rubbers such as propylene-butadiene copolymer rubber (PBR) and chloroprene rubber (CR) are exemplified, and polybutadiene rubber is particularly preferable. These conjugated diene polymers may be used alone or in a blend of two or more.

(Conjugated diene polymer)
The conjugated diene polymer can be obtained, for example, by polymerizing a monomer conjugated diene compound alone or a mixture of a monomer aromatic vinyl compound and a conjugated diene compound. In the rubber composition for a tread of the present invention, since it is necessary to introduce at least one nitrogen-containing functional group into the molecule of the conjugated diene polymer, (1) a monomer is used as a polymerization initiator. And a method for producing a polymer having a polymerization active site, and then modifying the polymerization active site with various nitrogen-containing modifiers, or (2) a polymerization initiator having a nitrogen-containing functional group as a monomer. It is preferable to obtain it by the method of polymerizing using.

(Modified conjugated diene polymer)
The polymerization initiator used for the synthesis of the modified conjugated diene polymer is preferably an organic lithium compound, more preferably hydrocarbyl lithium and a lithium amide compound. When an organic lithium compound is used as the polymerization initiator, the aromatic vinyl compound and the conjugated diene compound are polymerized by anionic polymerization. When hydrocarbyl lithium is used as a polymerization initiator, a polymer having a hydrocarbon group at the polymerization initiation terminal and the other terminal being a polymerization active site is obtained. On the other hand, when a lithium amide compound is used as the polymerization initiator, a polymer having a nitrogen-containing functional group at the polymerization initiation terminal and the other terminal being a polymerization active site is obtained, and the polymer is a nitrogen-containing modifier. It can be used as a modified conjugated diene polymer in the present invention without modification. In addition, the usage-amount of a polymerization initiator has the preferable range of 0.2-20 mmol per 100g of monomers.

  Examples of the hydrocarbyl lithium include ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-octyl lithium, n-decyl lithium, phenyl lithium, 2-naphthyl lithium, and 2-butyl-phenyl. Examples include lithium, 4-phenyl-butyllithium, cyclohexyllithium, cyclopentyllithium, reaction products of diisopropenylbenzene and butyllithium, and among these, ethyllithium, n-propyllithium, isopropyllithium, n-butyl Alkyl lithium such as lithium, sec-butyl lithium, tert-octyl lithium and n-decyl lithium is preferable, and n-butyl lithium is particularly preferable.

  On the other hand, the lithium amide compounds include lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene imide, lithium dodecamethylene imide, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium Dihexylamide, lithium diheptylamide, lithium dioctylamide, lythym-2-ethylhexylamide, lithium didecylamide, lithium-N-methylpiperazide, lithium ethylpropylamide, lithium ethylbutyramide, lithium methylbutyramide, lithium ethylbenzylamide, Examples include lithium methylphenethyl amide, among these, lithium hexamethylene imide, lithium pyrrolidide, lithium Cyclic lithium amide compounds such as piperidide, lithium heptamethylene imide and lithium dodecamethylene imide are preferred, and lithium hexamethylene imide and lithium pyrrolidide are particularly preferred.

As the lithium amide compound, the formula: Li-AM [wherein AM is a substituted amino group represented by the above formula (I) or a cyclic amino group represented by the formula (II)]
And at least one nitrogen-containing functional group selected from the group consisting of a substituted amino group represented by the formula (I) and a cyclic amino group represented by the formula (II). An introduced modified conjugated diene polymer is obtained. For example, when lithium hexamethyleneimide is used, a modified conjugated diene polymer into which at least one hexamethyleneimino group is introduced is obtained.

In the formula (I), R ¹ is an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, or an aralkyl group. Specifically, a methyl group, an ethyl group, a butyl group, an octyl group, a cyclohexyl group, Preferable examples include 3-phenyl-1-propyl group and isobutyl group. The plurality of R ¹ may be the same or different. On the other hand, in the formula (II), R ² is an alkylene group having 3 to 16 methylene groups, a substituted alkylene group, an oxyalkylene group or an N-alkylamino-alkylene group. Here, the substituted alkylene group includes a mono- to octa-substituted alkylene group, and examples of the substituent include a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, a bicycloalkyl group, and an aryl group. Groups and aralkyl groups. R ² is specifically preferably a trimethylene group, a tetramethylene group, a hexamethylene group, an oxydiethylene group, an N-alkylazadiethylene group, a dodecamethylene group, a hexadecamethylene group, or the like.

  The method for producing a conjugated diene polymer using the polymerization initiator is not particularly limited. For example, the polymer is obtained by polymerizing a monomer in a hydrocarbon solvent inert to the polymerization reaction. Can be manufactured. Here, hydrocarbon solvents inert to the polymerization reaction include propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene, trans-2-butene, cis -2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene, etc., may be used alone or in combination of two or more. May be. Moreover, you may implement the said polymerization reaction in presence of a randomizer. The polymerization is preferably carried out by solution polymerization, and the concentration of the monomer in the polymerization reaction solution is preferably in the range of 5 to 50% by mass, and more preferably in the range of 10 to 30% by mass. Further, the polymerization mode is not particularly limited, and may be batch type or continuous type. Furthermore, the reaction temperature of the polymerization reaction is preferably in the range of 0 to 150 ° C, more preferably in the range of 20 to 130 ° C.

  Further, in modifying the polymerization active site of the polymer having the polymerization active site with a modifier, the modifier used is a substituted or unsubstituted amino group, amide group, imino group, imidazole group, nitrile group or pyridyl. Nitrogen-containing compounds having groups are preferred. Examples of the nitrogen-containing compound suitable as the modifier include N, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane, N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane, and N, N-bis (trimethylsilyl). Protected primary amino group and silicon atom such as aminoethylmethyldimethoxysilane, N, N-bis (trimethylsilyl) aminoethylmethyldiethoxysilane, 1-trimethylsilyl-2-ethoxymethyl-1-aza-2-cyclopentane A compound containing a bifunctional silicon atom having at least an alkoxyl group bonded to a diisocyanate; isocyanate compounds such as diphenylmethane diisocyanate, crude MDI, trimethylhexamethylene diisocyanate, tolylene diisocyanate; 4- (dimethyl Mino) benzophenone, 4- (diethylamino) benzophenone, 4-dimethylamino-benzylidene aniline, 4-dimethylamino-benzylidene butyl amine, dimethyl imidazolidinone, N- methylpyrrolidone and the like.

Furthermore, in modifying the polymerization active site of the polymer obtained by polymerization with a polymerization initiator having a nitrogen-containing functional group, the above-mentioned modifier may be used, or the coupling described later as the modifier. An agent may be used. When a coupling agent is used as the modifier, a plurality of nitrogen-containing functional groups are introduced into the molecule of the resulting modified conjugated diene polymer, and the dispersibility of carbon black can be greatly improved. Specific examples of coupling agents include SnCl ₄ , R ³ SnCl ₃ , R ³ ₂ SnCl ₂ , R ³ ₃ SnCl, SiCl ₄ , R ³ SiCl ₃ , R ³ ₂ SiCl ₂ , R ³ ₃ SiCl and the like. Specific examples of R ³ include methyl group, ethyl group, n-butyl group, neophyll group, cyclohexyl group, n-octyl group, and 2-ethylhexyl group. In particular, SnCl ₄ and SiCl ₄ are preferable as the coupling agent.

  The modification reaction of the polymerization active site by the modifying agent is preferably performed by a solution reaction, and the solution may contain a monomer used at the time of polymerization. The reaction mode of the modification reaction is not particularly limited, and may be a batch type or a continuous type. Furthermore, the reaction temperature of the modification reaction is not particularly limited as long as the reaction proceeds, and the reaction temperature of the polymerization reaction may be employed as it is. In addition, the usage-amount of modifier | denaturant has the preferable range of 0.25-3.0 mol with respect to 1 mol of polymerization initiators used for manufacture of a polymer, and the range of 0.5-1.5 mol is still more preferable.

[Rubber component (A)]
The rubber component (A) of the rubber composition used in the present invention needs to contain natural rubber and the modified conjugated diene polymer, and the total amount of the natural rubber and the modified conjugated diene polymer is 70% by mass or more. In particular, it is preferable that the modified conjugated diene polymer is contained in the rubber component (A) in an amount of 10 to 50% by mass. When the content of the modified conjugated diene polymer in the rubber component (A) is less than 10% by mass, the effect of improving the carbon black dispersibility cannot be sufficiently obtained. On the other hand, when the content exceeds 50% by mass, the workability is improved. May decrease. In the case where a rubber component other than natural rubber and a modified conjugated diene polymer is included, a general rubber component used in the rubber industry can be blended.

  The rubber component (A) of the rubber composition according to the present invention has a mass ratio of natural rubber to modified conjugated diene polymer (natural rubber / modified conjugated diene polymer) of 90/10 to 50/50. It is preferable that the ratio is 80/20 to 50/50. Here, when the ratio of the modified conjugated diene polymer to the total of the natural rubber and the modified conjugated diene polymer is less than 10% by mass (that is, when the ratio of the natural rubber exceeds 90% by mass), the carbon black dispersion However, when the proportion of the modified conjugated diene polymer exceeds 50% by mass (that is, the proportion of natural rubber is less than 50% by mass), the improvement of the property is insufficient. In some cases, tear resistance may be insufficient, and workability may be reduced.

[Filler (B)]
The filler (B) according to the present invention is preferably carbon black and / or silica.
Carbon black used in the rubber composition according to the present invention preferably has a dibutyl phthalate (DBP) absorption amount is 40~180cm ³ / 100g, and more preferably 70~180cm ³ / 100g. If the DBP absorption of carbon black is 40 cm ^3/100 g or more, it is possible to suitably express the required tensile strength as a rubber composition for a tire. Moreover, if it is 180 cm < ³ > / 100 g or less, required elongation at the time of a cutting | disconnection can be ensured suitably.
Further, the carbon black used in the rubber composition according to the present invention, the nitrogen adsorption specific surface area: preferably (N ₂ SA compliant ASTM D3037-88) is 40~300m ² / g, 70~250m ² / It is more preferable that it is g, and it is still more preferable that it is 70-170 m < ² > / g. If the nitrogen adsorption specific surface area of carbon black is 40 m ² / g or more, the tensile strength required as a rubber composition for tires can be suitably expressed. Moreover, if it is 300 m < ² > / g or less, since the dispersibility in a rubber composition can fully be ensured, the abrasion resistance of a rubber composition, etc. improve.
Among general-purpose carbon blacks, HAF, N339, IISAF, ISAF, and SAF are preferably used.

Moreover, the carbon black disclosed by Unexamined-Japanese-Patent No. 2011-89075 can be used as carbon suitable for the rubber composition which concerns on this invention.
That is, (in accordance with ASTM D2414-88 (JIS K6217-97)) dibutyl phthalate (DBP) absorption of more preferably ^{110~180cm 3 / 100g, 140~180cm 3 /} 100g is particularly preferred. Nitrogen adsorption specific surface area (N ₂ SA: compliant ASTM D3037-88) is more and more preferably ^{90~160m 2 / g, 90~120m 2 /} g is particularly preferred. The specific coloring power (based on TINT: ASTM D3265-88) is preferably 100 to 130%, more preferably 100 to 120%. The toluene coloring transmittance (based on JIS K6218-97) is preferably 85 to 100%, more preferably 89 to 100%.

Moreover, there is no restriction | limiting in particular as silica, It can select and use arbitrarily from what is conventionally used as a filler for reinforcement of rubber conventionally.
Examples of the silica include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), colloidal silica, calcium silicate, aluminum silicate, and the like. Wet silica is most preferred because it is most effective. The BET specific surface area (measured in accordance with ISO 5794/1) of silica is preferably 40 to 350 m ² / g. Silica having a BET surface area within this range has an advantage that both rubber reinforcement and dispersibility in a rubber component can be achieved. In this respect, BET surface area is more preferably silica in the range of 80~350m ² / g, silica BET surface area in the range of 120~350m ² / g is particularly preferred. Examples of such silicas are Tosoh Silica Co., Ltd., trade name “Nip Seal AQ” (BET specific surface area = 205 m ² / g), “Nip Seal KQ”, Degussa product name “Ultra Gil VN 3” (BET specific surface area = 175 m). ² / g) can be used.

[Hydrazide Compound (C)]
The hydrazide compound (C) to be blended in the present invention is preferably a compound containing at least one hydrazide group represented by —C (═O) NHN═C (R ^a ) R ^b . However, R ^a and R ^b in the formula are each a hydrogen atom or a cyclic or non-cyclic hydrocarbon group that may contain O, S, and N elements having 1 to 18 carbon atoms, each independently. R ^a and R ^b may combine to form a cyclic hydrocarbon group. For example, it may be a saturated or unsaturated linear hydrocarbon group, branched hydrocarbon group, or cyclic hydrocarbon group, and may partially contain O, S, and N elements. Further, the cyclic hydrocarbon group may be a monocyclic or condensed polycyclic aromatic compound residue, and a heterocyclic-containing compound residue containing O, S, and N elements.
The hydrazide compound (C) may contain two or more hydrazide groups.
In this invention, it is preferable to contain 0.2-3 mass parts of at least 1 sort (s) of a hydrazide compound (C) with respect to 100 mass parts of rubber components (A).

Examples of the hydrazide compound (C) include isophthalic acid-N ² , N ⁴ -di (1-methylethylidene) dihydrazide and isophthalic acid-N ² , N ⁴ -di (1-methyl) derived from isophthalic acid dihydrazide. Propyridene) dihydrazide, dihydrazide compounds such as isophthalic acid-N ² , N ⁴ -di (1,3-dimethylbutylidene), salicylic acid-N ′-(1-methylethylidene) hydrazide, salicylic acid-derived from salicylic acid hydrazide N ′-(1-methylpropylidene) hydrazide, salicylic acid-N ′-(1-methylbutylidene) hydrazide, salicylic acid-N ′-(1,3-dimethylbutylidene) hydrazide, salicylic acid-N ′-(2- Furylmethylene) hydrazide, naphthoic acid hydrazide compounds represented by the following general formula (III), and the like. That.
Among these, a naphthoic acid hydrazide compound represented by the following general formula (III) is preferable.

式中Ｒ³及びＲ⁴は、それぞれ独立して水素原子又は炭素数１〜１８の炭化水素基を示し、Ｒ³とＲ⁴は互いに結合して環構造を形成していてもよい。

In the formula, R ³ and R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and R ³ and R ⁴ may be bonded to each other to form a ring structure.

Examples of the naphthoic acid hydrazide compound represented by the above general formula (III) include 1-hydroxy-N ′-(1-methylethylidene) -2-naphthoic acid hydrazide, 1-hydroxy-N ′-(1-methylpropylene). Ridene) -2-naphthoic acid hydrazide, 1-hydroxy-N ′-(1-methylbutylidene) -2-naphthoic acid hydrazide, 1-hydroxy-N ′-(1,3-dimethylbutylidene) -2-naphthoyl Acid hydrazide, 1-hydroxy-N ′-(2-furylmethylene) -2-naphthoic acid hydrazide, 3-hydroxy-N ′-(1-methylethylidene) -2-naphthoic acid hydrazide, 3-hydroxy-N′- (1-methylpropylidene) -2-naphthoic acid hydrazide, 3-hydroxy-N ′-(1-methylbutylidene) -2-naphthoic acid hydrazide, 3- Droxy-N ′-(1,3-dimethylbutylidene) -2-naphthoic acid hydrazide, 3-hydroxy-N ′-(2-furylmethylene) -2-naphthoic acid hydrazide, 3-hydroxy-N ′-(1 , 2-diphenylethylidene) -2-naphthoic acid hydrazide.
Among these, 3-hydroxy-N ′-(1,3-dimethylbutylidene) -2-naphthoic acid hydrazide (BMH) derived from 3-hydroxy-2-naphthoic acid hydrazide (HNH) is particularly preferable.

[Rubber composition]
The rubber composition used in the present invention contains 30 to 60 carbon blacks with respect to 100 parts by mass of the rubber component (A) containing natural rubber and at least one modified conjugated diene polymer having a nitrogen-containing functional group. It is preferable to mix part by mass. If the compounding amount of carbon black is 30 parts by mass or more, the reinforcing property of the rubber composition can be sufficiently ensured. On the other hand, if it is 60 parts by mass or less, the dispersibility of carbon black is improved, and the wear resistance, tear resistance and heat resistance of the rubber composition are improved. However, in the rubber composition in which the blending amount of carbon black is less than 30 parts by mass with respect to 100 parts by mass of the rubber component (A), silica is further added to 20 parts by mass or less, preferably 100 parts by mass with respect to the rubber component (A). By blending in the range of 0.5 to 15 parts by mass, the reinforcing property (abrasion resistance) of the rubber composition can be secured, and further, the hysteresis loss of the rubber composition can be greatly reduced. . That is, it is possible to achieve both low loss and reinforcement (wear resistance) of the rubber composition.
The rubber composition used in the present invention preferably contains 30 to 60 parts by mass of carbon black and 0.5 to 15 parts by mass of silica with respect to 100 parts by mass of the rubber component (A). When the content of carbon black and silica is within this range, the wear resistance, tear resistance and rolling resistance can be suitably improved.

In addition, when silica is blended in the rubber composition according to the present invention, in order to enhance the dispersibility of silica after further strengthening the reinforcing property by strengthening the bond between the silica-rubber component (A), Furthermore, it is preferable to use a silane coupling agent. The rubber composition according to the present invention preferably contains a silane coupling agent of (1/100) to (20/100) as a mass ratio (silane coupling agent / silica), and (5/100) to ( 20/100) silane coupling agent is more preferable, and (5/100) to (15/100) silane coupling agent is more preferable. If it is (1/100) or more, the effect of improving the low heat build-up of the rubber composition will be more suitably exhibited. If it is (20/100) or less, the cost of the rubber composition will be reduced, and the economic efficiency will be reduced. This is because it improves.
The silane coupling agent is not particularly limited, and bis (3-triethoxysilylpropyl) disulfide, bis (3-triethoxysilylpropyl) tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3- Preferred examples include trimethoxysilylpropylbenzothiazole disulfide, 3-octanoylthiopropyltriethoxysilane and the like.
When the rubber composition according to the present invention is a tread rubber composition, it is particularly preferable to use the above-mentioned silane coupling agent.

  The rubber composition production method of the present invention includes a rubber component (A) containing natural rubber and the modified conjugated diene polymer, a filler (B) such as carbon black and silica, and a hydrazide compound (C). In addition, compounding agents commonly used in the rubber industry, such as silane coupling agents, softeners, anti-aging agents, vulcanization accelerators, vulcanization accelerators, vulcanizers, etc. It can select suitably and mix | blend within the range which does not carry out. As these compounding agents, commercially available products can be suitably used. The method for producing the rubber composition of the present invention comprises blending the rubber component (A) with the carbon black and various compounding agents appropriately selected as necessary, and a specific kneading method, heating, extrusion, etc. Can be manufactured.

[tire]
In the tire of the present invention, the rubber composition obtained by the above-described method for producing a rubber composition is preferably used as a tread rubber, and is particularly suitable as a heavy load tire. In the tire of the present invention, when the rubber composition is used as a tread rubber (a tread grounding portion, or both a tread grounding portion and a base tread), wear resistance, tear resistance, and rolling resistance are highly balanced. Become. In the tire of the present invention, the rubber composition described above may be used for other members such as sidewalls other than treads and stiffeners (bead fillers). The tire of the present invention can be manufactured according to a conventional method. Moreover, as gas with which this tire is filled, inert gas, such as nitrogen, argon, helium other than normal or the air which adjusted oxygen partial pressure, can be used.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

Production Example 1: Production of Modified Polybutadiene Rubber (HMI-BR) In an approximately 900 ml pressure-resistant glass container that has been dried and purged with nitrogen, 283 g of cyclohexane, 50 g of 1,3-butadiene, 0.0057 mmol of 2,2-ditetrahydrofurylpropane, and After adding 0.513 mmol of hexamethyleneimine and further adding 0.57 mmol of n-butyllithium (BuLi), polymerization was carried out in a hot water bath at 50 ° C. equipped with a stirrer for 4.5 hours. The polymerization conversion rate at this time was almost 100%. Next, 0.100 mmol of tin tetrachloride as a modifying agent (coupling agent) was quickly added to this polymerization reaction system, and the mixture was further stirred at 50 ° C. for 30 minutes to carry out a modification reaction. Thereafter, 0.5 mL of an isopropanol solution (BHT concentration: 5% by mass) of 2,6-di-t-butyl-p-cresol (BHT) was added to the polymerization reaction system to stop the reaction, and further according to a conventional method. By drying, a modified polybutadiene rubber (HMI-BR) was obtained.

In addition, about the obtained HMI-BR, the peak on the most high molecular weight side with respect to the entire area of the molecular weight distribution curve by gel permeation chromatography (GPC) is determined from the integral ratio of the ¹ H-NMR spectrum to the vinyl bond amount of the butadiene moiety. The coupling rate was determined from the area ratio, and the glass transition temperature was determined from the inflection point of the DSC curve. The obtained HMI-BR had a vinyl bond content of the butadiene portion of 14%, a glass transition temperature (Tg) of -95 ° C, and a coupling efficiency of 65%.

Production Comparative Example 1 Production of Modified SBR <Production of SBR with Active End>
Add 1,3-butadiene in cyclohexane and styrene in cyclohexane to a dry, nitrogen-substituted 800 mL pressure-resistant glass container so that 1,3-butadiene 60 g and styrene 15 g are added, and 2,2-ditetrahydrofuryl is added. After adding 0.70 mmol of propane and further adding 0.70 mmol of n-butyllithium (BuLi), a polymerization reaction was performed in a hot water bath at 50 ° C. for 1.5 hours. The polymerization conversion rate at this time was almost 100%.
<Modification reaction process>
Next, 0.63 mmol of tetraethoxysilane was added to the polymerization reaction system as a primary modifier, and a modification reaction was further performed at 50 ° C. for 30 minutes.
<Post-polymerization treatment>
Next, an isopropanol solution of 2,6-di-tert-butyl-p-cresol (BHT) was added to the polymerization reaction system to stop the polymerization reaction. Thereafter, steam was blown to lower the solvent partial pressure (steam stripping) to remove the solvent, followed by vacuum drying to obtain a modified SBR.
The obtained modified SBR had a bound styrene content of 21% by weight, a bound vinyl content of the butadiene portion of 54%, and a Mooney viscosity [ML _{1 + 4} , 100 ° C.] of 40.

Production Comparative Example 2: Production of Unmodified SBR Unmodified SBR was obtained in the same manner as Production Comparative Example 1 except that the modification reaction was not performed in Production Comparative Example 1. The obtained unmodified SBR had a bound styrene content of 20% by mass, a bound vinyl content of the butadiene portion of 56%, and a Mooney viscosity [ML _{1 + 4} , 100 ° C.] of 16.

Production Example of Carbon Black Carbon black was produced using a carbon black production furnace 1 shown in FIG. Here, as the multistage cooling medium introducing means 12, a three-stage rapid cooling comprising a first rapid refrigerant introducing means 12-X, a second rapid refrigerant introducing means 12-Y, and a final rapid refrigerant introducing means 12-Z. Media introduction means were used. Moreover, in order to monitor the temperature in a manufacturing furnace, the said manufacturing furnace provided with the structure which can insert a thermocouple in an arbitrary several places in a furnace was used. In the carbon black production furnace, A heavy oil having a specific gravity of 0.8622 (15 ° C./4° C.) was used as the fuel, and heavy oil having the properties shown in Table 1 was used as the raw material oil. Further, carbon blacks A and B having the following physical properties were produced according to the operating conditions of the carbon black production furnace shown in Table 2.

About the obtained carbon black, dibutyl phthalate (DBP) absorption amount according to ASTM D2414-88 (JIS K6217-97), nitrogen adsorption specific surface area (N ₂ SA) according to ASTM D3037-88, ASTM The specific coloring power (TINT) was measured according to D3265-88, and the toluene coloring transmittance was measured according to JIS K6218-97.
Carbon black X (light transmittance of toluene%) of A 23, Z (light transmittance of toluene%) 89.3, DBP absorption ^{(cm 3 / 100g) 173,} N 2 SA (m 2 / g) 102, TINT ( %) 108, X (toluene extract light transmittance of% carbon black B) 31.7, Z (light transmittance of toluene%) 94.3, DBP absorption ^{(cm 3 / 100g) 173,} N 2 SA (m 2 / g) 102 and TINT (%) 108. Here, X means the toluene coloring permeability of carbon black after introduction of the first quenching medium from the raw material introduction position, and Z means the toluene coloring permeability of carbon black after the last quenching medium introduction. .
For details of the carbon black production method, refer to the aforementioned Japanese Patent Application Laid-Open No. 2011-89075.

Examples 1-5, Comparative Examples 1-7
Next, a rubber composition having the composition shown in Table 3 was prepared according to the kneading method shown in Table 3. The maximum temperature of the rubber composition in the first stage of kneading was set to 170 ° C., and the maximum temperature of the rubber composition in the final stage of kneading was set to 110 ° C. The maximum temperature of the rubber composition in the second stage of kneading in which the hydrazide compound (C) is kneaded with the rubber composition obtained in the first stage of kneading in Examples 1 to 5 is shown in Table 3. Similarly, the maximum temperature of the rubber composition in the second stage of kneading in Comparative Examples 1 to 7 is also shown in Table 3.
Using the above 12 kinds of rubber compositions as tread rubber, a heavy-duty tire of size 11R22.5 (rib pattern) was prototyped according to a conventional method, and the low heat buildup, wear resistance and tear resistance were evaluated by the following methods. . The results are shown in Table 3.

[note]
* 1, Modified polybutadiene rubber (HMI-BR) obtained in Production Example 1
* 2. Polybutadiene rubber manufactured by JSR Corporation, trade name “BR01”
* 3, Modified solution polymerization SBR (modifier tetraethoxysilane) obtained in Production Comparative Example 1
* 4 Unmodified solution polymerization SBR obtained in Production Comparative Example 2
* 5, carbon black ISAF (DBP oil absorption ^{(cm 3 / 100g): 114} , N 2 SA (m 2 / g): 119, TINT: 115)
* 6, Carbon black A obtained in the carbon black production example
* 7. Carbon black B obtained in the carbon black production example.
* 8, Silica: Tosoh Silica Co., Ltd., trade name “Nip Seal AQ”
* 9, Silane coupling agent: Bis (3-triethoxysilylpropyl) disulfide (average sulfur chain length: 2.35), Evonik silane coupling agent, trade name “Si75” (registered trademark)
* 10, softener: manufactured by Kao Corporation, Splendor R-400, glass transition temperature -80 ° C
* 11, anti-aging agent 6PPD: N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 6C”
* 12, naphthoic acid hydrazide (BMH): 3-hydroxy-N ′-(1,3-dimethylbutylidene) -2-naphthoic acid hydrazide, manufactured by Otsuka Chemical Co., Ltd. * 13, anti-aging agent TMDQ: 2,2 , 4-Trimethyl-1,2-dihydroquinoline polymer, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 224”
* 14, Vulcanization accelerator CZ: N-cyclohexyl-2-benzothiazolylsulfenamide, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “Noxeller CZ”

(1) tan δ (low exothermic property)
Using a spectrometer (manufactured by Ueshima Seisakusho Co., Ltd.), tan δ was measured at a frequency of 52 Hz, an initial strain of 10%, a measurement temperature of 60 ° C., and a dynamic strain of 1.0%. The tan δ of Comparative Example 1 was set to 100, and indexed by the following formula. A smaller index value indicates a lower exothermic property and a smaller hysteresis loss.
Low exothermic index = [(tan δ of test vulcanized rubber composition) / (tan δ of vulcanized rubber composition of Comparative Example 1)] × 100

(2) Wear resistance of the test tire (size: 11R22.5) mounted on the drive shaft of the truck and measured after running for 100,000 km. displayed. The larger the index value, the smaller the wear amount and the better the wear resistance.
Abrasion resistance index = [(Abrasion amount of vulcanized rubber composition of Comparative Example 1) / (Abrasion amount of test vulcanized rubber composition)] × 100

(3) Tear resistance The total length of the tear after the test tire was mounted on the drive shaft of the truck and traveled 100,000 km was measured, and the reciprocal number of the total tear length of Comparative Example 1 was displayed as an index. The larger the index value, the smaller the number of scratches and the better the tear resistance.
Tear resistance index = [(total tear length of vulcanized rubber composition of Comparative Example 1) / (total tear length of test vulcanized rubber composition)] × 100

  The method for producing a rubber composition of the present invention can provide a method for producing a rubber composition capable of reducing rolling resistance while improving durability such as wear resistance and tear resistance. Various pneumatic tire components for passenger cars, light trucks, light passenger cars, light trucks and large vehicles (trucks, buses, construction vehicles, etc.), especially pneumatic radial tire tread members (especially , A tread grounding member).

DESCRIPTION OF SYMBOLS 1 Carbon black production furnace 10 Reaction chamber 11 Reaction continuation and cooling chamber 12 Multistage rapid refrigerant body introduction means 12-X First rapid refrigerant body introduction means 12-Y Second rapid refrigerant body introduction means 12-Z Last rapid refrigerant body introduction means

Claims (14)

A first stage of kneading in which a rubber component (A) containing natural rubber and a modified conjugated diene polymer having at least one nitrogen-containing functional group and at least one filler (B) are kneaded; A kneading step of kneading the hydrazide compound (C) to the rubber composition obtained by the step, and kneading a vulcanizing agent and a vulcanization accelerator to the rubber composition obtained by the second step of the kneading. A method of producing a rubber composition having a final stage of kneading,
A rubber composition obtained by the first stage in the second stage by blending 0.5 to 15 parts by mass of silica contained in the filler (B) with respect to 100 parts by mass of the rubber component (A). A method for producing a rubber composition, comprising adding a silane coupling agent to a product together with a hydrazide compound (C) and kneading.   The method for producing a rubber composition according to claim 1, wherein the nitrogen-containing functional group is a substituted or unsubstituted amino group, amide group, imino group, imidazole group, nitrile group or pyridyl group. The nitrogen-containing functional group has the following formula (I):

[Wherein, a plurality of R ¹ are each independently an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, or an aralkyl group. And a substituted amino group represented by the following formula (II):

[Wherein, R ² represents an alkylene group having 3 to 16 methylene groups, a substituted alkylene group, an oxyalkylene group or an N-alkylamino-alkylene group. ] The manufacturing method of the rubber composition of Claim 2 selected from the group which consists of cyclic amino group represented by these.   The method for producing a rubber composition according to claim 3, wherein the nitrogen-containing functional group is a hexamethyleneimino group.   The method for producing a rubber composition according to any one of claims 1 to 4, wherein the conjugated diene polymer is a polybutadiene rubber.   The method for producing a rubber composition according to any one of claims 1 to 5, wherein the maximum temperature of the rubber composition in the second stage of kneading is 150 ° C or higher.   The manufacturing method of the rubber composition in any one of Claims 1-6 which contains at least 1 sort (s) of the said hydrazide compound (C) 0.2-3 mass parts with respect to 100 mass parts of said rubber components (A). . The rubber composition according to claim 1, wherein the hydrazide compound (C) is a compound containing at least one hydrazide group represented by —C (═O) NHN═C (R ^a ) R ^b. Manufacturing method.
[However, R ^a and R ^b in the formula are a hydrogen atom or a cyclic or non-cyclic hydrocarbon group which may contain O, S, and N elements having 1 to 18 carbon atoms, each independently. R ^a and R ^b may combine to form a cyclic hydrocarbon group. ] The method for producing a rubber composition according to claim 8, wherein the hydrazide compound (C) is a hydrazide compound represented by the general formula (III).

[Wherein, R ³ and R ⁴ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and R ³ and R ⁴ may be bonded to each other to form a ring structure. ]   The method for producing a rubber composition according to any one of claims 1 to 9, wherein the filler (B) is carbon black and / or silica.   30 parts by mass to 60 parts by mass of the carbon black and 0.5 parts by mass of the silica with respect to 100 parts by mass of the rubber component (A) containing the natural rubber and the modified conjugated diene polymer having at least one nitrogen-containing functional group. The manufacturing method of the rubber composition of Claim 10 containing -15 mass parts.   The rubber composition according to claim 10 or 11, wherein the rubber composition further contains a silane coupling agent of (1/100) to (20/100) as a mass ratio [silane coupling agent / silica]. Manufacturing method.   The rubber composition obtained by the manufacturing method of the rubber composition in any one of Claims 1-12.   A tire using the rubber composition according to claim 13 as a tire member.

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