JP2010013602A - Tire for heavy load - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire for heavy load which has excellent low rolling resistance (low heat build-up property) without loss of wear resistance, and which has significantly improved tire durability. <P>SOLUTION: The tire for heavy load utilizes as a tread rubber, a rubber composition containing a rubber component and a filler such as carbon black and silica, wherein the rubber component contains a modified polybutadiene rubber comprising an amine-based functional group such as a protic amino group and a protected amino group of 10-70 mass% and a natural rubber. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heavy duty tire. More particularly, the present invention relates to a heavy-duty tire having excellent low rolling resistance (low heat generation) and significantly improved tire durability without impairing wear resistance.

In recent years, with respect to heavy-duty tires used for trucks and buses, the demand for improved durability has become more severe. In order to meet such demands, it has been required to improve wear resistance simultaneously with further reduction of rolling resistance as tire performance. As a technique for reducing the rolling resistance of the tire, although a technique by optimizing the tire structure has been studied, the most common technique is to use a material having lower heat generation as the rubber composition.
The tread rubber generates heat by repeatedly undergoing a large deformation operation during traveling. However, the heat generation may reduce the fracture characteristics of the tread rubber and reduce the durability of the tire. Therefore, the influence of the tread rubber on the rolling resistance (exothermic property) is large, and the most common method is to use a material having a lower exothermic property as the rubber composition.

In order to obtain such a rubber composition with low exothermicity, many technical developments of modified rubber have been made so far for rubber compositions containing carbon black or silica as a filler. For example, a method has been proposed in which the polymerization active terminal of a conjugated diene polymer obtained by anionic polymerization using an organolithium compound is modified with an alkoxysilane derivative containing a functional group that interacts with a filler.
However, most of these are applied to polymers that can easily ensure the living property of the polymer terminals, and there are few modification improvements for polybutadiene, which is particularly important for tire tread rubber, etc., and rubbers containing carbon black and silica A sufficient modification effect is not always obtained in the composition.
Therefore, in order to overcome the above drawbacks, a conjugated diene polymer is reacted with a specific functional group-containing compound (modifier) having a nitrogen atom in the molecule, and a conjugated diene polymer in which carbon black is easily dispersed is obtained. Proposed production methods (see Patent Document 1), polymers in which an amino group is introduced at a polymerization terminal using a lithium amide initiator (for example, see Patent Document 2), etc. have been proposed. A diene rubber (for example, see Patent Document 3) in which is introduced is proposed.
Although the polymers obtained by these methods can achieve various physical property improvements to some extent in each of the carbon black compounding and silica compounding, in the above documents, amino groups are mainly introduced into the polymer. The method has been described in detail, and the relationship between the structure of the polymer itself and each performance has not been mentioned more than general matters.

In addition, low rolling resistance can be achieved by using carbon black having low reinforcing properties or by reducing the amount of carbon black. However, these methods obviously lower the wear resistance, for example, the strength of the tread is reduced.
On the other hand, if carbon black with a fine particle size with high reinforcing properties is used, it is possible to improve the wear resistance, but by making the particle size fine, the dispersion of carbon black in the rubber component becomes worse, and the rubber composition There was a problem that workability of kneading of the product was lowered and heat generation of the vulcanized rubber composition was increased.

JP 2001-139634 A JP 7-53616 A JP-A-9-71687

  An object of the present invention is to provide a heavy duty tire that has excellent low rolling resistance (low heat generation) and significantly improved tire durability under such circumstances without impairing wear resistance. To do.

As a result of intensive studies to achieve the above object, the present inventor has found that a heavy duty tire using a rubber composition containing a specific amount of a specific modified polybutadiene diene rubber in a tread can achieve the object. I found it. The present invention has been completed based on such findings.
That is, the present invention uses [1] a rubber composition containing a rubber component and a filler, and the rubber component contains 10 to 70% by mass of an amine-based functional group-modified polybutadiene rubber and natural rubber. Heavy duty tires, characterized by
[2] The heavy duty tire according to the above [1], wherein the modified polybutadiene rubber has a protic amino group and / or a protected amino group as an amine functional group,
[3] The heavy duty tire according to [1] or [2], wherein the modified polybutadiene rubber further has a hydrocarbyloxysilane group,
[4] The heavy duty tire according to the above [3], wherein the modified polybutadiene rubber has a protic amino group and / or a protected amino group and a hydrocarbyloxysilane group.
[5] The heavy duty tire according to the above [4], having a protic amino group and / or a protected amino group and a hydrocarbyloxysilane group at the same polymerization terminal,
[6] The protic amino group and / or the protected amino group is —NH ₂ , —NHR ^a , —NL ¹ L ² and —NR ^b L ³ (wherein R ^a and R ^b are each a hydrocarbon group, And L ¹ , L ² and L ³ each represent a hydrogen atom or a dissociable protecting group.) The heavy duty tire according to any one of the above [2] to [5], which is at least one group selected from ,
[7] The above-mentioned [3], wherein the modified polybutadiene rubber is modified by reacting a compound having a protected amino group and a hydrocarbyloxysilane group in the molecule with the polymerization active terminal of the conjugated diene polymer. [6] Any heavy duty tire,
[8] The heavy duty tire according to [7], wherein the compound having a protected amino group and a hydrocarbyloxysilane group in the molecule is a bifunctional silicon compound having a protected primary amino group.

（式中、Ｒ¹、Ｒ²は、それぞれ独立に炭素数１〜２０の炭化水素基、Ｒ³〜Ｒ⁵は、それぞれ独立に炭素数１〜２０の炭化水素基、Ｒ⁶は炭素数１〜１２のアルキレン基、Ａは反応性基、ｆは１〜１０の整数を示す。）で表されるケイ素化合物、一般式（ＩＩ）

（式中、Ｒ⁷〜Ｒ¹¹は、それぞれ独立に炭素数１〜２０の炭化水素基、Ｒ¹²は炭素数１〜１２のアルキレン基を示す。）で表されるケイ素化合物及び、一般式（ＩＩＩ）

（式中、Ｒ¹、Ｒ²は、それぞれ独立に炭素数１〜２０の炭化水素基、Ｒ³〜Ｒ⁵は、それぞれ独立に炭素数１〜２０の炭化水素基、Ｒ⁶は炭素数１〜１２のアルキレン基、Ｒ¹³は炭素数１〜１２のアルキレン基、Ａは反応性基、ｆは１〜１０の整数を示す。）で表されるケイ素化合物から選ばれる少なくとも一種である上記［８］に記載の重荷重用タイヤ、
［１０］ 一般式（Ｉ）におけるＡがハロゲン原子、炭素数１〜２０のアルコキシ基又はヒドロキシ基である上記［９］の重荷重用タイヤ、
［１１］ 変性ポリブタジエンゴム重合体の重合活性末端に、分子内に保護化アミノ基とヒドロカルビルオキシシラン基とを有する化合物を反応させ、変性させたのち、周期律表（長周期型）の３族、４族、５族、１２族、１３族、１４族及び１５族のうちのいずれかに属する元素の化合物からなる縮合促進剤の存在下で、前記化合物が関与する縮合反応を施したものである上記［１］〜［１０］いずれかの重荷重用タイヤ、
［１２］ 前記縮合促進剤が、チタン（Ｔｉ）、ジルコニウム（Ｚｒ）、ビスマス（Ｂｉ）、又はアルミニウム（Ａｌ）の化合物からなり、前記縮合促進剤を構成する化合物は、前記元素のアルコキシド、カルボン酸塩、又はアセチルアセトナート錯塩である上記［１１］の重荷重用タイヤ、
［１３］ 前記縮合促進剤が、チタンの化合物からなるチタン系縮合促進剤である上記［１２］に記載の重荷重用タイヤ、
［１４］ チタン系縮合促進剤が、チタンのアルコキシド、カルボン酸塩及びアセチルアセトナート錯塩の中から選ばれる少なくとも一種である上記［１３］の重荷重用タイヤ、
［１５］ 前記充填材として、前記ゴム成分１００質量部当たり、カーボンブラック２０〜６５質量部とシリカ０〜３０質量部とを含むと共にカーボンブラックとシリカの合計量が３０〜６５質量部である上記［１］〜［１４］いずれかの重荷重用タイヤ、
［１６］ 前記シリカに対して、シランカップリング剤を２〜２０質量％含有する上記［１５］の重荷重用タイヤ、
［１７］ シランカップリング剤が、下記一般式（ＩＶ）

［式中、Ｒ¹⁴はＲ¹⁹Ｏ−、Ｒ¹⁹Ｃ（＝Ｏ）Ｏ−、Ｒ¹⁹Ｒ²⁰Ｃ＝ＮＯ−、Ｒ¹⁹Ｒ²⁰Ｎ−又は−（ＯＳｉＲ¹⁹Ｒ²⁰）_m（ＯＳｉＲ¹⁸Ｒ¹⁹Ｒ²⁰）（ただし、Ｒ¹⁹及びＲ²⁰は、それぞれ独立に水素原子又は炭素数１〜１８の一価の炭化水素基、である。）Ｒ¹⁵はＲ¹⁴、水素原子又は炭素数１〜１８の一価の炭化水素基、Ｒ¹⁶はＲ¹⁴、Ｒ¹⁵又は−［Ｏ（Ｒ²¹Ｏ）_a］_0.5−基（ただし、Ｒ²¹は炭素数１〜１８のアルキレン基、ａは１〜４の整数である。）、Ｒ¹⁷は炭素数１〜１８の二価の炭化水素基、Ｒ¹⁸は炭素数１〜１８の一価の炭化水素基を示し、ｘ、ｙ及びｚは、ｘ＋ｙ＋２ｚ＝３、０≦ｘ≦３、０≦ｙ≦２、０≦ｚ≦１の関係を満たす数である。］で表される上記［１６］の重荷重用タイヤ、及び
［１８］ ゴム成分が、（Ａ）変性ポリブタジエンゴムを１０〜７０質量％と、天然ゴム９０〜３０質量％との組合わせを含む上記［１］〜［１７］いずれかの重荷重用タイヤ、
を提供するものである。 [9] The compound containing a bifunctional silicon atom is represented by the general formula (I)

Wherein R ¹ and R ² are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{3 to} R ⁵ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁶ is a carbon number 1 A silicon compound represented by formula (II): an alkylene group of ~ 12, A is a reactive group, and f is an integer of 1 to 10.

(Wherein R ^{7 to} R ¹¹ each independently represents a hydrocarbon group having 1 to 20 carbon atoms, and R ¹² represents an alkylene group having 1 to 12 carbon atoms) and a general formula ( III)

Wherein R ¹ and R ² are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{3 to} R ⁵ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁶ is a carbon number 1 -12 alkylene group, R ¹³ is an alkylene group having 1 to 12 carbon atoms, A is a reactive group, and f is an integer of 1 to 10). 8], a heavy-duty tire according to
[10] The heavy duty tire according to [9], wherein A in the general formula (I) is a halogen atom, an alkoxy group having 1 to 20 carbon atoms, or a hydroxy group,
[11] After reacting a compound having a protected amino group and a hydrocarbyloxysilane group in the molecule with the polymerization active terminal of the modified polybutadiene rubber polymer, the group 3 of the periodic table (long-period type) In the presence of a condensation accelerator composed of a compound of an element belonging to any of Group 4, Group 5, Group 12, Group 13, Group 14 and Group 15, a condensation reaction involving the compound is performed. A heavy duty tire according to any one of the above [1] to [10],
[12] The condensation accelerator is composed of a compound of titanium (Ti), zirconium (Zr), bismuth (Bi), or aluminum (Al), and the compound constituting the condensation accelerator includes an alkoxide of the element, a carboxyl [11] a heavy duty tire which is an acid salt or an acetylacetonate complex salt,
[13] The heavy load tire according to [12], wherein the condensation accelerator is a titanium-based condensation accelerator made of a titanium compound.
[14] The heavy load tire according to [13], wherein the titanium-based condensation accelerator is at least one selected from titanium alkoxides, carboxylates, and acetylacetonate complex salts,
[15] The filler, which contains 20 to 65 parts by mass of carbon black and 0 to 30 parts by mass of silica per 100 parts by mass of the rubber component, and the total amount of carbon black and silica is 30 to 65 parts by mass [1] to [14] any heavy duty tire,
[16] The heavy duty tire according to [15] above, containing 2 to 20% by mass of a silane coupling agent relative to the silica.
[17] The silane coupling agent is represented by the following general formula (IV):

[Wherein R ¹⁴ represents R ¹⁹ O—, R ¹⁹ C (═O) O—, R ¹⁹ R ²⁰ C═NO—, R ¹⁹ R ²⁰ N— or — (OSiR ¹⁹ R ²⁰ ) _m (OSiR ¹⁸ R ¹⁹ R ²⁰ ) (where R ¹⁹ and R ²⁰ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms.) R ¹⁵ is R ¹⁴ , a hydrogen atom or 1 to 1 carbon atoms. 18 monovalent hydrocarbon groups, R ¹⁶ is R ¹⁴ , R ¹⁵ or — [O (R ²¹ O) _a ] _0.5 — group (where R ²¹ is an alkylene group having 1 to 18 carbon atoms, a is 1 to 1) R ¹⁷ is a divalent hydrocarbon group having 1 to ¹⁸ carbon atoms, R ¹⁸ is a monovalent hydrocarbon group having 1 to ¹⁸ carbon atoms, and x, y, and z are x + y + 2z. = 3, 0 ≦ x ≦ 3, 0 ≦ y ≦ 2, 0 ≦ z ≦ 1. [16] The heavy load tire of [16], and [18] The rubber component includes a combination of 10 to 70% by mass of (A) modified polybutadiene rubber and 90 to 30% by mass of natural rubber. [1] to [17] Any heavy duty tire,
Is to provide.

  The present invention can provide a heavy duty tire having excellent low rolling resistance (low heat generation) and significantly improved tire durability without impairing wear resistance.

First, the modified polybutadiene rubber of the present invention will be described.
[Modified polybutadiene rubber]
The modified polybutadiene rubber of the present invention (hereinafter sometimes referred to as modified BR) is required to be modified with an amine functional group.
In the modified BR of the present invention, the position of the polymer into which the amine functional group is introduced is not particularly limited and may be a polymerization terminal or a side chain of the polymer chain. From the viewpoints of ease of introduction of the polymer and the ability to suppress energy loss from the polymer terminal to improve low heat build-up, the polymer terminal is preferable.
Preferred examples of the amine functional group include a protic amino group and / or a protected amino group. In the modified BR, those having a hydrocarbyloxysilane group in the polymer together with the protic amino group and / or the protected amino group are more preferable.
These functional groups are preferably introduced at the polymerization terminal for the above reasons, and particularly preferably introduced at the same polymerization terminal.
Compounds having these functional groups used for the modification of the above-mentioned protic amino group, protected amino group, hydrocarbyloxysilane group, and base BR (hereinafter referred to as BR or unmodified BR) (hereinafter referred to as a modifier) Etc.) will be described in detail later.
As a method for producing a modified BR of the present invention, a method for producing a modified BR by obtaining a BR having an active end and reacting a modifier with the active end can be employed.

(Manufacture of BR)
In the present invention, BR having an active end is obtained by homopolymerizing 1,3-butadiene, and there is no particular limitation on the production method thereof. Solution polymerization method, gas phase polymerization method, bulk polymerization method Any of these can be used, but the solution polymerization method is particularly preferable. Moreover, any of a batch type and a continuous type may be sufficient as the superposition | polymerization form.
The active site metal present in the BR molecule is preferably one selected from alkali metals and alkaline earth metals, preferably alkali metals, and particularly preferably lithium metal.
In the solution polymerization method, for example, the target BR can be produced by anionic polymerization of 1,3-butadiene using an organic alkali metal compound, particularly a lithium compound as a polymerization initiator.
When using the solution polymerization method, the 1,3-butadiene concentration in the solvent is preferably 5 to 50% by mass, more preferably 10 to 30% by mass.

  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. Is a polymerization active site. When the latter lithium amide compound is used, BR 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, phenyllithium, 2-naphthyllithium, 2-butyl-phenyllithium, 4-phenyl-butyllithium, cyclohexyllithium, cyclobenthyllithium, and reactive organisms of diisopropenylbenzene and butyllithium. Of these, n-butyllithium is particularly preferred.

  On the other hand, examples of the lithium amide compound include lithium hexamethylene imide, lithium pyrrolidide, lithium piperide, lithium heptamethylene imide, lithium dodecamethylene imide, lithium dimethyl amide, lithium diethyl amide, lithium dibutyl amide, lithium dipropyl amide, Heptylamide, lithium dihexylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium-N-methylpiperazide, lithium ethylpropylamide, lithium ethylbutyramide, lithium ethylbenzylamide, lithium methylphenethyl Examples include amides. Among these, in view of the interaction effect on carbon black and the ability to initiate polymerization, cyclic lithium amides such as lithium hexamethylene imide, lithium pyrrolidide, lithium piperide, lithium heptamethylene imide, and lithium dodecamethylene imide are preferable, In particular, lithium hexamethylene imide and lithium pyrrolidide are suitable.

  In general, these lithium amide compounds prepared from a secondary amine and a lithium compound can be used 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 BR 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, in a hydrocarbon solvent such as an aliphatic, alicyclic or aromatic hydrocarbon compound, 1,3-butadiene is used as the polymerization initiator. If desired, the desired BR can be obtained by anionic polymerization in the presence of the randomizer used.

  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, 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 compound that controls the microstructure of BR, for example, the content of cis-1,4-bond, the content of vinyl bond, and the like. 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, oxolanylpropane oligomers [especially those containing 2,2-bis (2-tetrahydrofuryl) -propane, etc.], triethylamine, pyridine , N-methylmorpholine, N, N, N ′, N′-tetramethylethylenediamine, ethers such as 1,2-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 polymerization medium used and the polymerization temperature, but if desired, a higher pressure can be used. Such a pressure is an appropriate method such as pressurizing the reaction system with an inert gas for the polymerization reaction. It is obtained by.

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, it is preferable that the glass transition temperature (Tg) calculated | required by the differential thermal analysis method of obtained BR is -95 degreeC--15 degreeC. By setting the glass transition temperature within the above range, it is possible to suppress the increase in viscosity and obtain BR that is easy to handle.

(Modification of BR)
In the present invention, a predetermined modifier is reacted with the active terminal of the BR having the active terminal thus obtained, and an amine functional group such as a protic amino group and / or a protected group is formed at the polymerization terminal. An amino group, preferably a protic amino group and / or a protected amino group and a hydrocarbyloxysilane group are introduced. More preferably, the protic amino group and / or the protected amino group and the hydrocarbyloxysilane group are introduced into the same polymerization terminal.
As the protonic amino group and / or a protected amino group, for example _{^{-NH 2, -NHR a, -NL 1}} L 2 and -NR ^b L ³ (provided that, R ^a and R ^b are each a hydrocarbon group And L ¹ , L ² and L ³ each represent a hydrogen atom or a dissociable protecting group).
Examples of the hydrocarbon group represented by R ^a and R ^b include various alkyl groups, alkenyl groups, aryl groups, and aralkyl groups. L ¹ , L ² , and L ³ may be any protecting group that can be easily dissociated, and are not particularly limited, and examples thereof include groups described below.

<Modifier>
In the present invention, the modified BR preferably has a protic amino group and / or a protected amino group and a hydrocarbyloxysilane group at the same polymerization terminal. Therefore, the modifying agent is protected within the same molecule. It is preferable to use a bifunctional silicon compound having a secondary amino group.
Examples of the bifunctional silicon compound having a protected primary amino group in the same molecule include compounds represented by general formula (I), general formula (II) and general formula (III).

Wherein R ¹ and R ² are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{3 to} R ⁵ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁶ is a carbon number 1 -12 alkylene groups, A is a reactive group, preferably a halogen atom or an alkoxy group having 1 to 20 carbon atoms, and f is an integer of 1 to 10.)

(In the formula, R ^{7 to} R ¹¹ each independently represent a hydrocarbon group having 1 to 20 carbon atoms, and R ¹² represents an alkylene group having 1 to 12 carbon atoms.)

（式中、Ｒ¹、Ｒ²は、それぞれ独立に炭素数１〜２０の炭化水素基、Ｒ³〜Ｒ⁵は、それぞれ独立に炭素数１〜２０の炭化水素基、Ｒ⁶は炭素数１〜１２のアルキレン基、Ｒ¹³は炭素数１〜１２のアルキレン基、Ａは反応性基、ｆは１〜１０の整数を示す。）

(Wherein, R ^1, R ² each independently represent a hydrocarbon group having 1 to 20 carbon atoms, R ³ to R ⁵ each independently represent a hydrocarbon group having 1 to 20 carbon atoms, R ⁶ is C 1 -C 12 alkylene group, R ¹³ is an alkylene group having 1 to 12 carbon atoms, a represents a reactive group, f is an integer from 1 to 10.)

In the above formulas (I) to (III), preferred examples of the alkylene group having 1 to 12 carbon atoms of R ⁶ or R ¹² include a methylene group, an ethylene group, and a propylene group. Examples of the hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as methyl group, ethyl group and propyl group, and aryl groups such as aralkyl groups such as phenyl group, tolyl group, naphthyl group and benzyl group. .
Further, two of R ³ , R ⁴ and R ⁵ in formula (I) may be bonded to form a 4- to 7-membered ring together with the silicon atom to which they are bonded. Two of R ⁹ , R ¹⁰ and R ¹¹ in (II) may be bonded to form a 4- to 7-membered ring together with the silicon atom to which they are bonded. R ¹³ is an alkylene group having 1 to 12 carbon atoms.
A is a reactive group, preferably a halogen atom, an alkoxy group having 1 to 20 carbon atoms or a hydroxy group. The hydroxy group bonded to the silicon atom obtained by hydrolysis in advance is more reinforcing filler than the alkoxy group. In particular, when reacting with silica, the reactivity with silica becomes higher, the dispersibility of silica in the rubber composition is improved, and the low exothermic property of the rubber composition is improved. Furthermore, when the characteristic group that generates a hydroxy group by hydrolysis is an alkoxy group, a volatile organic compound (VOC, particularly alcohol) is generated, but a hydroxy group is not generated.

Examples of the bifunctional silicon compound having a protected primary amino group in the same molecule include N, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane, N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane, N, N-bis (trimethylsilyl) aminoethylmethyldimethoxysilane, N, N-bis (trimethylsilyl) aminoethylmethyldiethoxysilane, and 1-trimethylsilyl-2-ethoxy-2-methyl-1-aza-2-silacyclo Examples include pentane.
Examples of the compound wherein A is a halogen atom include N, N-bis (trimethylsilyl) aminopropylmethylmethoxychlorosilane, N, N-bis (trimethylsilyl) aminopropylmethylethoxychlorosilane, and N, N-bis (trimethylsilyl) amino. Examples thereof include ethylmethylmethoxychlorosilane and N, N-bis (trimethylsilyl) aminoethylmethylethoxychlorosilane.
Preferably, N, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane, N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane, 1-trimethylsilyl-2-ethoxy-2-methyl-1-aza-2- Silacyclopentane.
These modifiers may be used individually by 1 type, and may be used in combination of 2 or more types. The modifier may be a partial condensate.
Here, the partial condensate means a product in which a part (not all) of the modifier SiOR is SiOSi bonded by condensation.
In the above modification reaction, it is preferable that the polymer to be used has at least 10% of the polymer chain having a living property.

In the denaturing reaction using the denaturing agent, the amount of the denaturing agent used is preferably 0.5 to 200 mmol / kg · BR. The content is more preferably 1 to 100 mmol / kg · BR, and particularly preferably 2 to 50 mmol / kg · BR. Here, BR means the mass of only a polymer not containing an additive such as an anti-aging agent added during or after production. By making the usage-amount of a modifier into the said range, it is excellent in the dispersibility of a filler, and the fracture | rupture characteristic after vulcanization | cure, an abrasion characteristic, and low exothermic property are improved.
The method for adding the modifier is not particularly limited, and examples thereof include a batch addition method, a division addition method, and a continuous addition method. preferable.
Further, the modifier may be bonded to any of the polymerization initiation terminal, the polymerization termination terminal, the polymer main chain, and the side chain, but it can improve the low heat build-up by suppressing energy loss from the polymer terminal. Therefore, it is preferably introduced at the polymerization initiation terminal or the polymerization termination terminal.

<Condensation accelerator>
In the present invention, a condensation accelerator is preferably used in order to accelerate the condensation reaction involving the alkoxysilane compound having a protected amino group used as the modifier.
Examples of such a condensation accelerator include a compound containing a tertiary amino group, or among group 3, 4, 5, 12, 13, 14, and 15 of the periodic table (long period type). An organic compound containing one or more elements belonging to any of the above can be used. Further, as a condensation accelerator, an alkoxide, carboxylate, or acetyl containing at least one metal selected from the group consisting of titanium (Ti), zirconium (Zr), bismuth (Bi), and aluminum (Al). An acetonate complex salt is preferred.
The condensation accelerator used here can be added before the modification reaction, but is preferably added to the modification reaction system during and / or after the modification reaction. When added before the denaturation reaction, a direct reaction with the active end may occur, and a hydrocarbyloxy group having a protected primary amino group at the active end may not be introduced.
The addition time of the condensation accelerator is usually 5 minutes to 5 hours after the start of the modification reaction, preferably 15 minutes to 1 hour after the start of the modification reaction.

Specific examples of the condensation accelerator include tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, tetraisopropoxytitanium, tetra-n-butoxytitanium, tetra-n-butoxytitanium oligomer, tetra-sec- Butoxytitanium, tetra-tert-butoxytitanium, tetra (2-ethylhexoxy) titanium, bis (octanediolate) bis (2-ethylhexoxy) titanium, tetra (octanediolate) titanium, titanium lactate, titanium dipropoxybis (triethanol) Aminate), titanium dibutoxybis (triethanolaminate), titanium tributoxy systemate, titanium tripropoxy systemate, titanium ethyl Hexyldiolate, titanium tripropoxyacetylacetonate, titanium dipropoxybis (acetylacetonate), titanium tripropoxyethylacetoacetate, titaniumpropoxyacetylacetonatebis (ethylacetoacetate), titanium tributoxyacetylacetonate, titanium dibutoxy Bis (acetylacetonate), titanium tributoxyethyl acetoacetate, titanium butoxyacetylacetonate bis (ethylacetoacetate), titanium tetrakis (acetylacetonate), titanium diacetylacetonate bis (ethylacetoacetate), bis (2-ethyl) Hexanoate) titanium oxide, bis (laurate) titanium oxide, bis (naphthe G) titanium oxide, bis (stearate) titanium oxide, bis (oleate) titanium oxide, bis (linoleate) titanium oxide, tetrakis (2-ethylhexanoate) titanium, tetrakis (laurate) titanium, tetrakis (naphthate) titanium, Mention may be made of compounds containing titanium such as tetrakis (stearate) titanium, tetrakis (oleate) titanium, tetrakis (linoleate) titanium and the like.

  Examples of the condensation accelerator include tris (2-ethylhexanoate) bismuth, tris (laurate) bismuth, tris (naphthate) bismuth, tris (stearate) bismuth, tris (oleate) bismuth, and tris (linoleate). Bismuth, tetraethoxyzirconium, tetra-n-propoxyzirconium, tetraisopropoxyzirconium, tetra-n-butoxyzirconium, tetra-sec-butoxyzirconium, tetra-tert-butoxyzirconium, tetra (2-ethylhexoxy) zirconium, zirconium tributoxy Stearate, zirconium tributoxyacetylacetonate, zirconium dibutoxybis (acetylacetonate), zirconium tributoxyethylacetoacetate Zirconium butoxyacetylacetonate bis (ethylacetoacetate), zirconium tetrakis (acetylacetonate), zirconium diacetylacetonate bis (ethylacetoacetate), bis (2-ethylhexanoate) zirconium oxide, bis (laurate) zirconium oxide, Bis (naphthate) zirconium oxide, bis (stearate) zirconium oxide, bis (oleate) zirconium oxide, bis (linoleate) zirconium oxide, tetrakis (2-ethylhexanoate) zirconium, tetrakis (laurate) zirconium, tetrakis (naphthate) Zirconium, Tetrakis (stearate) zirconium, Tetrakis (oleate) zirconium, Tet Mention may be made of a kiss (linoleate) zirconium and the like.

  Also, triethoxyaluminum, tri-n-propoxyaluminum, triisopropoxyaluminum, tri-n-butoxyaluminum, tri-sec-butoxyaluminum, tri-tert-butoxyaluminum, tri (2-ethylhexoxy) aluminum, aluminum dibutoxy Stearate, aluminum dibutoxyacetylacetonate, aluminum butoxybis (acetylacetonate), aluminum dibutoxyethylacetoacetate, aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate), tris (2-ethylhexanoate) ) Aluminum, Tris (laurate) aluminum, Tris (naphthate) aluminum, Tris (stearate) aluminum, To Scan (oleate) aluminum, tris (linolate) aluminum, and the like.

  Of the above-mentioned condensation accelerators, titanium-based condensation accelerators are preferred, and titanium metal alkoxides, titanium metal carboxylates, or titanium metal acetylacetonate complex salts are particularly preferred. The amount of the condensation accelerator used is preferably such that the number of moles of the compound is 0.1 to 10 as the molar ratio to the total amount of hydrocarbyloxy groups present in the reaction system, and 0.5 to 5 Particularly preferred. By setting the use amount of the condensation accelerator within the above range, the condensation reaction proceeds efficiently.

The condensation reaction in the present invention proceeds in the presence of the above-described condensation accelerator and water vapor or water. An example of the presence of water vapor is a solvent removal treatment by steam stripping, and the condensation reaction proceeds during steam stripping.
The condensation reaction may be carried out in an aqueous solution, and the condensation reaction temperature is preferably 85 to 180 ° C, more preferably 100 to 170 ° C, and particularly preferably 110 to 150 ° C.
By setting the temperature during the condensation reaction within the above range, the condensation reaction can be progressed and completed efficiently, and the deterioration of the quality due to the aging reaction of the polymer due to the change in BR over time can be suppressed.

The condensation reaction time is usually about 5 minutes to 10 hours, preferably about 15 minutes to 5 hours. By setting the condensation reaction time within the above range, the condensation reaction can be completed smoothly.
In addition, the pressure of the reaction system at the time of condensation reaction is 0.01-20 Mpa normally, Preferably it is 0.05-10 Mpa.
There is no restriction | limiting in particular about the format in the case of performing a condensation reaction in aqueous solution, You may carry out by a continuous type using apparatuses, such as a batch type reactor and a multistage continuous type reactor. Moreover, you may perform this condensation reaction and a desolvent simultaneously.
The amino group derived from the modifying agent of the modified BR in the present invention is generated by performing the deprotection treatment as described above. Specific examples of suitable deprotection treatments other than the solvent removal treatment using steam such as steam stripping described above will be described in detail below.
That is, the amino protecting group is converted to a free amino group by hydrolysis. By removing this solvent, a modified BR having an amino group can be obtained. In addition, the deprotection treatment of the protected amino group derived from the modifier can be performed as necessary in any stage from the stage including the condensation treatment to the solvent removal to the dry polymer.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the modified BR obtained in the present invention is preferably 10 to 150, more preferably 15 to 80. By setting the Mooney viscosity value within the above range, a rubber composition having excellent kneading workability and mechanical properties after vulcanization can be obtained.
The modified BR in the present invention has amine functional groups such as protic amino groups and / or protected amino groups in the polymer, preferably these amine functional groups and hydrocarbyloxysilane groups. The dissociative groups of the protective amino group and the protected amino group have a good interaction with carbon black and silica, while the hydrocarbyloxysilane group has a particularly excellent interaction with silica. Yes. When the rubber composition containing the modified BR is used for a tread rubber, it is possible to obtain a heavy duty tire having low rolling resistance while maintaining abrasion resistance.

Next, the rubber composition used for the tread of the heavy duty tire of the present invention will be described.
[Rubber composition]
The rubber composition contains a rubber component and a filler, and the rubber component needs to contain 10 to 70% by mass of an amine functional group-modified polybutadiene rubber and natural rubber.
(Rubber component)
The rubber composition used for the tread of the heavy duty tire of the present invention needs to contain 10 to 70% by mass of the modified BR as a rubber component. The preferable content of the modified BR in the rubber component is 20 to 60% by mass. Furthermore, it is necessary to contain natural rubber as a rubber component. The preferable content of the natural rubber is 90 to 30% by mass, more preferably 80 to 40% by mass, based on the total amount with the modified BR. By setting the amounts of the modified BR and natural rubber in the rubber component within the above ranges, a rubber composition having desired physical properties can be obtained.
Further, by blending natural rubber, the mechanical properties of the composition are improved and the kneading workability of the composition is improved.
Furthermore, the rubber composition in the present invention includes, as desired, a synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-α-olefin copolymer rubber, ethylene as a rubber component, as long as the object of the present invention is not impaired. -Α-Olefin-diene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chlorobrene rubber, halogenated butyl rubber, and mixtures thereof can be added. Further, some of them may have a branched structure by using a polyfunctional type, for example, a modifier such as tin tetrachloride or silicon tetrachloride.

(Filler)
In the rubber composition used for the tread of the heavy duty tire of the present invention, it is necessary to contain a reinforcing filler as the filler. Examples of the reinforcing filler usually include carbon black and silica. As long as the carbon black enhances the mechanical performance of the rubber layer and improves the workability and the like, the range of I ₂ adsorption amount, CTAB specific surface area, N ₂ adsorption amount, DBP adsorption amount and the like was appropriately selected. Known carbon black can be used. As the type of carbon black, for example, known ones such as SAF, ISAF, HAF, HAF-HS can be appropriately selected and used. In view of wear resistance, ISAF and SAF having a fine particle diameter are preferable, and SAF is particularly preferable.

Silica does not represent only silicon dioxide in a narrow sense, but means a silicate-based filler. Specifically, in addition to anhydrous silicic acid, hydrous silicic acid, calcium silicate, aluminum silicate, etc. Contains silicate. Of these, wet silica having excellent wear resistance is preferred. Examples of such silica include “Nipseal AQ” manufactured by Tosoh Silica Co., BET210 m ² / g.
The filler preferably includes 20 to 65 parts by mass of carbon black and 0 to 30 parts by mass of silica per 100 parts by mass of the rubber component, and the total amount of carbon black and silica is preferably 30 to 65 parts by mass. More preferably, it is 40-55 mass parts. By setting the amount of the filler within the above range, the wear resistance is maintained, and the deterioration of the kneading workability of the composition is suppressed.

(Silane coupling agent)
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 reinforcement and low heat build-up. The blending amount of the preferred silane coupling agent varies depending on the kind of the silane coupling agent, but is preferably selected in the range of 2 to 20% by mass with respect to silica. If the amount is less than 2% by mass, the effect as a coupling agent is not sufficiently exhibited, and if it exceeds 20% by mass, 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 mass.

  Preferred silane coupling agents include the following general formula (IV)

A silane coupling agent comprising a protected mercaptosilane represented by the formula:
In the general formula (IV), R ¹⁴ represents R ¹⁹ O—, R ¹⁹ C (═O) O—, R ¹⁹ R ²⁰ C═NO—, R ¹⁹ R ²⁰ N— or — (OSiR ¹⁹ R ²⁰ ) _m ( OSiR ¹⁸ R ¹⁹ R ²⁰ ) (where R ¹⁹ and R ²⁰ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms), R ¹⁵ is R ¹⁴ , a hydrogen atom or carbon. A monovalent hydrocarbon group of 1 to 18, R ¹⁶ is R ¹⁴ , R ¹⁵ or — [O (R ²¹ O) _a ] _0.5 — group (where R ²¹ is an alkylene group of 1 to 18 carbon atoms, a Is an integer of 1 to 4.), R ¹⁷ is a divalent hydrocarbon group having 1 to ¹⁸ carbon atoms, R ¹⁸ is a monovalent hydrocarbon group having 1 to ¹⁸ carbon atoms, and x, y and z Is a number satisfying the relationship of x + y + 2z = 3, 0 ≦ x ≦ 3, 0 ≦ y ≦ 2, and 0 ≦ z ≦ 1.
In the general formula (IV), examples of the monovalent hydrocarbon group having 1 to 18 carbon atoms include an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, and an aryl group having 6 to 18 carbon atoms. And an aralkyl group having 7 to 18 carbon atoms. Here, the alkyl group and alkenyl group may be linear, branched or cyclic, and the aryl group and aralkyl group have a substituent such as a lower alkyl group on the aromatic ring. Also good.

Specific examples of the monovalent hydrocarbon group having 1 to 18 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, and tert-butyl group. , Pentyl group, hexyl group, octyl group, decyl group, dodecyl group, cyclopentyl group, cyclohexyl group, vinyl group, propenyl group, allyl group, hexenyl group, octenyl group, cyclopentenyl group, cyclohexenyl group, phenyl group, Examples include tolyl group, xylyl group, naphthyl group, benzyl group, phenethyl group, naphthylmethyl group and the like.
In the general formula (IV), the alkylene group having 1 to 18 carbon atoms represented by R ²¹ may be linear, branched or cyclic, and is particularly preferably linear. is there. 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, a decamethylene group, and a dodecamethylene group.
Examples of the divalent hydrocarbon group having 1 to 18 carbon atoms represented by R ¹⁷ include an alkylene group having 1 to 18 carbon atoms, an alkenylene group having 2 to 18 carbon atoms, and a cycloalkylene having 5 to 18 carbon atoms. Groups, cycloalkylalkylene groups having 6 to 18 carbon atoms, arylene groups having 6 to 18 carbon atoms, and aralkylene groups having 7 to 18 carbon atoms. The alkylene group and alkenylene group may be linear or branched, and the cycloalkylene group, cycloalkylalkylene group, arylene group, and aralkylene group may have a substituent such as a lower alkyl group on the ring. You may have.
R ¹⁷ is preferably an alkylene group having 1 to 6 carbon atoms, particularly preferably a linear alkylene group such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, or a hexamethylene group. it can.
Examples of the silane coupling agent represented by the general formula (IV) include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3 -Lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexa Noylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2 Octanoylthiopropyl ethyltrimethoxysilane, 2- deca Neu thio ethyltrimethoxysilane, and the like of 2-lauroyl thio ethyltrimethoxysilane.
In this invention, the said silane coupling agent may be used individually by 1 type, and may be used in combination of 2 or more type.
Furthermore, in order to couple the silane coupling agent and the polymer, it is preferable to add a proton donor typified by DPG (diphenylguanidine) or the like as a deprotecting agent in the final kneading step. The amount used is preferably from 0.1 to 5.0 parts by weight, more preferably from 0.2 to 3.0 parts by weight, per 100 parts by weight of the rubber component.

  In addition, a sulfur-containing silane compound having a specific structure having an organooxysilyl group at both ends of a molecule described in the WO 2004/000930 pamphlet published by the present applicant and having a sulfide or polysulfide at the center of the molecule is disclosed in the present invention. When the rubber composition is used as a silane coupling agent, the rubber composition has a low unvulcanized viscosity and a high silica dispersibility, and when used as a tire tread member, has high wear resistance. , Suppresses the temperature rise of the running tire.

Furthermore, conventionally used silane coupling agents can also be applied.
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-dimethylthiocarba Yl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxy Ethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl Tetrasulfide, dimethoxymethylsilylpropyl benzothiazolyl tetrasulfide, etc. are mentioned. Of these, bis 3-triethoxysilylpropyl) polysulfide and 3-trimethoxysilylpropyl benzothiazolyl tetrasulfide are preferable.
One of these silane coupling agents may be used alone, or two or more thereof may be used in combination.

(Preparation of rubber composition)
In the rubber composition of the present invention, various chemicals usually used in the rubber industry, for example, a vulcanizing agent, a vulcanization accelerator, a process oil, an antioxidant, 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.
As said vulcanizing agent, sulfur etc. are mentioned, The usage-amount is 0.1-10.0 mass parts as a sulfur content with respect to 100 mass parts of rubber components, More preferably, it is 1.0-5. 0 parts by mass. If the amount is less than 0.1 parts by mass, the rupture strength, wear resistance, and low heat build-up of the vulcanized rubber may be reduced. If the amount exceeds 10.0 parts by mass, the rubber elasticity is lost.

  The vulcanization accelerator that can be used in the present invention is not particularly limited, and examples thereof include M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), and CZ (N-cyclohexyl-2-benzothiazyl). Sulfenamide) and other guanidine vulcanization accelerators such as DPG (diphenylguanidine) can be mentioned, and the amount used is 0.1 with respect to 100 parts by mass of (A) rubber component. -5.0 mass parts is preferable, More preferably, it is 0.2-3.0 mass parts.

  Examples of the process oil that can be used in the rubber composition of the present invention include paraffinic, naphthenic, and aromatic oils. Aromatics are used for applications that emphasize tensile strength and wear resistance, and naphthenic or paraffinic systems are used for applications that emphasize hysteresis loss and low-temperature characteristics. The amount used is preferably 0 to 100 parts by mass with respect to 100 parts by mass of the rubber component (A), and if it exceeds 100 parts by mass, the tensile strength and low heat build-up of the vulcanized rubber tend to deteriorate.

  The rubber composition in the present invention is obtained by kneading using a kneading machine such as a roll or an internal mixer, and is vulcanized after molding and used for a tire tread.

[Heavy tires]
The heavy duty tire of the present invention is produced by a usual method using the rubber composition. That is, if necessary, a rubber composition containing various chemicals as described above is processed into a tread at an unvulcanized stage, and pasted and molded by a normal method on a tire molding machine, and a raw tire is molded. Is done. The green tire is heated and pressed in a vulcanizer to obtain a tire.
The heavy duty tire of the present invention thus obtained has excellent low rolling resistance (low heat buildup) without impairing wear resistance, and can significantly improve tire durability.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
The physical properties and various properties of the polymer were measured according to the following methods.
<< Physical properties of modified BR >>
<Microstructure analysis method>
1,4-cis bond content (%) and vinyl bond content (%) were measured by an infrared method (Morello method).

<< Evaluation of tire performance (tire size 11R22.5) >>
(1) Evaluation of rolling resistance The rolling resistance at 80 km / h was measured with a normal load and internal pressure, and the value of Comparative Example 1 was expressed as an index, and the smaller the value, the lower the rolling resistance.
(2) Evaluation of wear resistance A test tire was mounted on a drive shaft of a truck, and the amount of wear after running for 100,000 km was measured. The value of Comparative Example 1 was taken as 100 and expressed as an index. It shows that abrasion resistance is so favorable that the value of an index | exponent is large.

Synthesis Example 1 Synthesis of Modification Agent-A After adding 36 g of 3-aminopropylmethyldiethoxysilane (manufactured by Gelest) as an aminosilane moiety in 400 ml of dichloromethane solvent in a glass flask equipped with a stirrer under a nitrogen atmosphere, 48 ml of trimethylsilane chloride (Aldrich) and 53 ml of triethylamine were added to the solution as protective sites, and the mixture was stirred for 17 hours at room temperature. Thereafter, the solvent was removed by applying the reaction solution to an evaporator to obtain a reaction mixture. The reaction mixture was distilled under reduced pressure under the condition of 665 Pa to obtain 40 g of N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane (Modifier-A) as a 130-135 ° C. fraction.

Synthesis Example 2 Synthesis of Modifier-B Under a nitrogen atmosphere, 41 g of 3-aminopropyltriethoxysilane (manufactured by Gelest) was added as an aminosilane moiety to 400 ml of dichloromethane solvent in a glass flask equipped with a stirrer, followed by further protection. 48 ml of trimethylsilane chloride (manufactured by Aldrich) and 53 ml of triethylamine were added to the solution as the site, and the mixture was stirred for 17 hours at room temperature. Thereafter, the solvent was removed by applying the reaction solution to an evaporator to obtain a composition reaction solution. The reaction solution was distilled under reduced pressure under 5 mm / Hg conditions to obtain 40 g of N, N-bis (trimethylsilyl) aminopropyltriethoxysilane (modifier-B) as a 125 to 130 ° C. fraction.

Synthesis Example 3 Synthesis of Modification Agent-C N, N-bis (trimethylsilyl) was performed according to Synthesis Example 1 except that 30 g of 36 g of 3-aminopropyldimethylethoxysilane (Gelest) was used as the aminosilane moiety. Aminopropyldimethylethoxysilane (Modifier-C) was obtained.

Production Example 1 Production of Modified BR-1 Into a nitrogen-substituted 5 L autoclave, 1.4 kg of cyclohexane, 250 g of 1,3-butadiene, and 2,2-ditetrahydrofurylpropane (0.0285 mmol) were injected under nitrogen. Then, 2.85 mmol of n-butyllithium (BuLi) was added thereto, followed by polymerization in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The reaction conversion of 1,3-butadiene was almost 100%. Subsequently, without deactivating the polymerization catalyst, the polymerization solution was kept at a temperature of 50 ° C., 1129 mg of the modifier-A obtained in Synthesis Example 1 was added, and the modification reaction was performed for 30 minutes. Thereafter, 2,6-di-tert-butyl-p-cresol was added to the polymer solution. Next, the solvent was removed by steam stripping and the protected primary amino group was deprotected, and the rubber was dried by a hot roll adjusted to 110 ° C. to obtain modified BR-1. The resulting modified BR-1 had a cis-1,4 bond content of 40% and a vinyl bond content of 20%.

Production Example 2 Production of Modified BR-2 In Production Example 1, N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine (modifier-) was used instead of modifier-A1129 mg. D) Modified BR-2 was obtained in the same manner as in Production Example 1 except that 1020 mg was used.
The modified BR-2 had almost the same cis-1,4 bond content and vinyl bond content as the modified BR-1.
As N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine, the trade name “Silaace S340” manufactured by Chisso Corporation was used.

Production Example 3 Production of Modified BR-3 The polymer before modification was produced in the same manner as in Production Example 1. Subsequently, without deactivating the polymerization catalyst, the polymerization temperature was maintained at 50 ° C., and 922 mg of N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole (modifier-E) was added to effect the modification reaction. Went for a minute. Thereafter, 4.09 g of bis (2-ethylhexanoic acid) tin was added as a condensation accelerator, and the mixture was further stirred for 15 minutes. Finally, 2,6-di-tert-butyl-p-cresol is added to the polymer solution after the reaction, and then the solvent is removed by steam stripping, and the rubber is dried by a hot roll adjusted to 110 ° C. As a result, modified BR-3 was obtained.
This modified BR-3 had almost the same cis-1,4 bond content and vinyl bond content as that of the modified BR-1.

Production Example 4 Production of Modified BR-4 In Production Example 1, modified BR-4 was prepared in the same manner as in Production Example 1, except that the modifier-B1231 mg obtained in Synthesis Example 2 was used instead of the modifier-A1129 mg. Got.
The cis-1,4 bond content and vinyl bond content of the modified BR-4 were almost the same as those of the modified BR-1.

Production Example 5 Production of Modified BR-5 Modified BR-5 in the same manner as in Production Example 1 except that, in Production Example 1, the modifying agent-C1027 mg obtained in Synthesis Example 3 was used instead of the modifying agent-A1129 mg. Got.
The modified BR-5 had almost the same cis-1,4 bond content and vinyl bond content as the modified BR-1.

Production Example 6 Production of Modified BR-6 The polymer before the modification was produced in the same manner as in Production Example 1. Subsequently, without deactivating the polymerization catalyst, the polymerization temperature was maintained at 50 ° C., 1129 mg of the modifier-A obtained in Synthesis Example 1 was added, and the modification reaction was performed for 15 minutes. Thereafter, 6.19 g of tetrakis (2-ethylhexoxy) titanium was added as a condensation accelerator, and the mixture was further stirred for 15 minutes. Finally, 2,6-di-tert-butyl-p-cresol was added to the polymer solution after the reaction, and then the solvent was removed by steam stripping and the protected primary amino group was deprotected, The rubber was dried with a hot roll adjusted to a temperature of 1, to obtain modified BR-6.
The modified BR-6 had almost the same cis-1,4 bond content and vinyl bond content as the modified BR-1.

Production Example 7 Production of Modified BR-7 Performed in the same manner as in Production Example 6, except that 8.11 g of tetrakis (2-ethyl-1,3-hexanediolato) titanium was used as the condensation accelerator in Production Example 6. As a result, modified BR-7 was obtained.
The modified BR-7 had almost the same cis-1,4 bond content and vinyl bond content as the modified BR-1.

Production Example 8 Production of Modified BR-8 The same procedure as in Production Example 6 was carried out except that 4.09 g of bis (2-ethylhexanoic acid) tin was used as the condensation accelerator in Production Example 6, and modified BR- 8 was obtained.
The modified BR-6 had almost the same cis-1,4 bond content and vinyl bond content as the modified BR-1.

Production Example 9 Production of Modified BR-9 The same procedure as in Production Example 6 was conducted except that 3.97 g of bis (2-ethylhexanoate) zirconium oxide was used as the condensation accelerator in Production Example 6. BR-9 was obtained.
The modified BR-9 had almost the same cis-1,4 bond content and vinyl bond content as the modified BR-1.

Examples 1-16 and Comparative Examples 1-3
Nineteen types of rubber compositions having the composition shown in Table 1 were prepared and applied to a tread rubber having a tire size of 11R22.5, and rolling resistance and wear resistance were evaluated. The evaluation results are shown in Table 1.

[note]
1) Polybutadiene rubber: “BR01” manufactured by JSR
2) Modified polybutadiene rubber Modified BR-1: obtained in Production Example 1 Modifier: N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysila
Modified BR-2: obtained in Production Example 2 Modifier: N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1
-Propanamine-Modified BR-3: Obtained in Production Example 3 Modifier: N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole
B condensation accelerator: bis (2-ethylhexanoic acid) tin modified BR-4: obtained in Production Example 4 modifier: N, N-bis (trimethylsilyl) aminopropyltriethoxysilane modified BR-5: What was obtained in Production Example 5 Modifier: N, N-bis (trimethylsilyl) aminopropyldimethylethoxysila
Modified BR-6: Obtained in Production Example 6 Modifier: N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysila
Condensation accelerator: tetrakis (2-ethylhexoxy) titanium Modified BR-7: obtained in Production Example 7 Modifier: N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysila
Condensation accelerator: tetrakis (2-ethyl-1,3-hexanediolato) titanium Modified BR-8: obtained in Production Example 8 Modifier: N, N-bis (trimethylsilyl) aminopropylmethyldiethoxy Syrah
Condensation accelerator: bis (2-ethylhexanoic acid) tin Modified BR-9: obtained in Production Example 9 Modifier: N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysila
Condensation accelerator: bis (2-ethylhexanoate) zirconium oxide 3) Carbon black N134: Tokai Carbon Co., Ltd. 4) Carbon black N234: Tokai Carbon Co., Ltd. 5) Silica: Tosoh Silica Co., Ltd. “Nipseal AQ”
6) Silane coupling agent: “Si69” manufactured by Degussa
7) Anti-aging agent 6PPD: “NOCRACK 6C” manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
8) Vulcanization accelerator CZ: “Noxeller CZ” manufactured by Ouchi Shinsei Chemical Co., Ltd.
From Table 1, it can be seen that the example is superior in the balance of wear resistance and rolling resistance in the tire performance as compared with the comparative example.

  The heavy-duty tire of the present invention has excellent low rolling resistance (low heat generation) without impairing wear resistance, and has significantly improved tire durability, and is suitable for truck and bus tires. Can be applied to.

Claims (18)

  A heavy duty tire comprising a rubber composition containing a rubber component and a filler, wherein the rubber component contains 10 to 70% by mass of an amine functional group-modified polybutadiene rubber and natural rubber. .   The heavy duty tire according to claim 1, wherein the modified polybutadiene rubber has a protic amino group and / or a protected amino group as an amine functional group.   The heavy duty tire according to claim 1 or 2, wherein the modified polybutadiene rubber further has a hydrocarbyloxysilane group.   The heavy duty tire according to claim 3, wherein the modified polybutadiene rubber has a protic amino group and / or a protected amino group and a hydrocarbyloxysilane group.   The heavy-duty tire according to claim 4, which has a protic amino group and / or a protected amino group and a hydrocarbyloxysilane group at the same polymerization terminal. A protic amino group and / or a protected amino group are —NH ₂ , —NHR ^a , —NL ¹ L ² and —NR ^b L ³ (wherein R ^a and R ^b each represent a hydrocarbon group, L ¹ , L ^2, and L ³ each represent a hydrogen atom or a dissociable protecting group.) The heavy load tire according to claim 2.   The modified polybutadiene rubber is obtained by reacting a compound having a protected amino group and a hydrocarbyloxysilane group in the molecule with the polymerization active terminal of the conjugated diene polymer, and modifying it. Heavy duty tires as described in 1.   The heavy-duty tire according to claim 7, wherein the compound having a protected amino group and a hydrocarbyloxysilane group in the molecule is a bifunctional silicon compound having a protected primary amino group. The compound containing a bifunctional silicon atom is represented by the general formula (I)

Wherein R ¹ and R ² are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{3 to} R ⁵ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁶ is a carbon number 1 A silicon compound represented by formula (II): an alkylene group of ~ 12, A is a reactive group, and f is an integer of 1 to 10.

(Wherein R ^{7 to} R ¹¹ each independently represents a hydrocarbon group having 1 to 20 carbon atoms, and R ¹² represents an alkylene group having 1 to 12 carbon atoms) and a general formula ( III)

Wherein R ¹ and R ² are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{3 to} R ⁵ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁶ is a carbon number 1 -12 alkylene group, R ¹³ is an alkylene group having 1 to 12 carbon atoms, A is a reactive group, and f is an integer of 1 to 10). The heavy duty tire according to 8.   The heavy-duty tire according to claim 9, wherein A in the general formula (I) is a halogen atom, an alkoxy group having 1 to 20 carbon atoms, or a hydroxy group.   A compound having a protected amino group and a hydrocarbyloxysilane group in the molecule is reacted at the polymerization active terminal of the modified polybutadiene rubber polymer, and then modified, and then group 3, group 4 of the periodic table (long period type). 6. A condensation reaction involving the compound in the presence of a condensation accelerator composed of a compound of an element belonging to any one of Group 5, Group 12, Group 13, Group 14 and Group 15. The heavy duty tire according to any one of 1 to 10.   The condensation accelerator is composed of a compound of titanium (Ti), zirconium (Zr), bismuth (Bi), or aluminum (Al), and the compound constituting the condensation accelerator includes an alkoxide of the element, a carboxylate, The heavy duty tire according to claim 11, wherein the tire is a complex salt of acetylacetonate.   The heavy-duty tire according to claim 12, wherein the condensation accelerator is a titanium-based condensation accelerator made of a titanium compound.   The heavy-duty tire according to claim 13, wherein the titanium-based condensation accelerator is at least one selected from titanium alkoxides, carboxylates, and acetylacetonate complex salts.   The filler includes 20 to 65 parts by mass of carbon black and 0 to 35 parts by mass of silica per 100 parts by mass of the rubber component, and the total amount of carbon black and silica is 30 to 65 parts by mass. The heavy duty tire according to any one of 14.   The heavy-duty tire according to claim 15, comprising 2 to 20% by mass of a silane coupling agent with respect to the silica. Silane coupling agent is represented by the following general formula (IV)

[Wherein R ¹⁴ represents R ¹⁹ O—, R ¹⁹ C (═O) O—, R ¹⁹ R ²⁰ C═NO—, R ¹⁹ R ²⁰ N— or — (OSiR ¹⁹ R ²⁰ ) _m (OSiR ¹⁸ R ¹⁹ R ²⁰ ) (where R ¹⁹ and R ²⁰ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 18 carbon atoms.) R ¹⁵ is R ¹⁴ , a hydrogen atom or 1 to 1 carbon atoms. 18 monovalent hydrocarbon groups, R ¹⁶ is R ¹⁴ , R ¹⁵ or — [O (R ²¹ O) _a ] _0.5 — group (where R ²¹ is an alkylene group having 1 to 18 carbon atoms, a is 1 to 1) R ¹⁷ is a divalent hydrocarbon group having 1 to ¹⁸ carbon atoms, R ¹⁸ is a monovalent hydrocarbon group having 1 to ¹⁸ carbon atoms, and x, y, and z are x + y + 2z. = 3, 0 ≦ x ≦ 3, 0 ≦ y ≦ 2, 0 ≦ z ≦ 1. The heavy-duty tire according to claim 16 represented by:   The heavy-duty tire according to any one of claims 1 to 17, wherein the rubber component includes a combination of 10 to 70 mass% of modified polybutadiene rubber and 90 to 30 mass% of natural rubber.