JP2009126360A - Heavy-duty tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heavy-duty tire with highly balanced breaking resistance and rim slip properties of a rubber chafer. <P>SOLUTION: The heavy-duty tire contains a rubber component and a filler. The rubber component is characterized in that a rubber composition containing amine system functional group-modified styrene-butadiene copolymer of 10-100 mass% and natural rubber is used for the rubber chafer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heavy duty tire. More specifically, the present invention relates to a heavy-duty tire using a rubber composition that highly balances fracture resistance and rim slipperiness with a gum chafer.

In heavy-duty tires for trucks and buses, the rim bead seat and rim flange are connected to the radially inner ends of the sidewall portions extending radially inward from both ends of the tread portion, and are seated on the rim. Conventionally, it has been widely practiced to arrange a gum chafer at the contact portion to prevent rim rubbing of the bead portion, rim slip, etc., and to improve air sealability.
As described above, the gum chafer part is an important member for fixing the tire and the rim, and must have high fracture resistance.
In addition, there is a problem of rim slip in the gum chafer part, and rim slip can be suppressed by making the gum chafer highly elastic, and a method of increasing the amount of carbon black and a resin typified by phenol resin is taken. ing. (For example, refer to Patent Document 1 or 2). However, exothermicity (hysteresis loss) deteriorates and as a result, the fracture resistance decreases. It is an important issue to develop a gum chafer capable of highly balancing the fracture resistance and the rim slip.

On the other hand, as a method of reducing exothermic property (hysteresis loss) as a rubber component, a method of introducing a functional group into the polymerization terminal of styrene-butadiene copolymer of various structures polymerized with organolithium initiator in hydrocarbon solvent is proposed. Has been. For example, a styrene-butadiene copolymer obtained by modifying or coupling a polymerization terminal with a tin compound, a styrene-butadiene copolymer having a polymerization terminal modified with an isocyanate compound, or the like are known. These modified polymers exhibit an effect of reducing hysteresis loss and excellent fracture characteristics, particularly in a composition containing carbon black as a reinforcing material.
In addition, in both carbon black compounding and silica compounding, amino group-introduced polymers are known as effective modified polymers. For carbon black compounding, a polymer in which an amino group is introduced at the polymerization terminal using a lithium amide initiator (for example, see Patent Document 3) has been proposed, and for silica compounding, a diene having an amino group introduced therein. System rubbers (see, for example, Patent Document 4) have been 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.

On the other hand, methods for increasing the elasticity of carbon black by increasing the amount of carbon black or blending resin are known, but exothermicity deteriorates. Currently, in heavy-duty tires, the elongation at break (Eb) = It has been found that 100% modulus (M ₁₀₀ ) = 3.5 Mpa is required for rim slip of 450%. However, it is difficult to develop a rubber composition in which these two performances are compatible, and the actual situation is that either the fracture characteristics or the rim sliding is sacrificed in each market.

JP-A-8-3368 JP 7-315015 A JP 7-53616 A JP-A-9-71687

  Under such circumstances, an object of the present invention is to provide a heavy-duty tire that highly balances the fracture resistance and rim slipperiness of a gum chafer.

（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２価の炭化水素基、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２価の炭化水素基を示す。）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２価の炭化水素基、Ｒ¹³は炭素数１〜１２の２価の炭化水素基、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］の重荷重用タイヤ、 As a result of intensive studies to achieve the above object, the present inventor has found that a rubber composition containing a styrene-butadiene copolymer and natural rubber obtained by introducing a specific amine functional group and modifying it is the object. Found that it can be achieved. The present invention has been completed based on such findings.
That is, the present invention
[1] A rubber composition containing a rubber component and a filler, wherein the rubber component contains 10 to 100% by mass of an amine functional group-modified styrene-butadiene copolymer and natural rubber is used for a gum chafer. Heavy duty tires, characterized by
[2] The heavy duty tire according to the above [1], wherein the amine functional group-modified styrene-butadiene copolymer has a protic amino group and / or a protected amino group as an amine functional group,
[3] The heavy duty tire according to the above [2], wherein the amine functional group-modified styrene-butadiene copolymer further has a hydrocarbyloxysilane group.
[4] The heavy load tire according to [3], wherein the amine functional group-modified styrene-butadiene copolymer has a protic amino group and / or a protected amino group and a hydrocarbyloxysilane group at a polymerization terminal,
[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 amine-based functional group-modified styrene-butadiene copolymer is modified by reacting a compound having a protected amino group and a hydrocarbyloxysilane group in the molecule at the polymerization active terminal of the styrene-butadiene copolymer. The heavy duty tire according to any one of the above [2] to [6],
[8] The heavy duty tire according to [7] above, 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,
[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 divalent hydrocarbon group of ˜12, A is a reactive group, f is an integer of 1 to 10, and a silicon compound represented by the general formula (II)

(Wherein R ^{7 to} R ¹¹ each independently represents a hydrocarbon group having 1 to 20 carbon atoms, and R ¹² represents a divalent hydrocarbon group having 1 to 12 carbon atoms) 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 To 12 divalent hydrocarbon groups, R ¹³ is a divalent hydrocarbon group having 1 to 12 carbon atoms, A is a reactive group, and f is an integer of 1 to 10. [8] the heavy duty tire which is at least one selected

［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、アミン系官能基変性スチレン−ブタジエン共重合体１０〜１００質量％と、天然ゴム天然ゴム９０〜０質量％とからなる上記［１］〜［１７］いずれかの重荷重用タイヤ、
を提供するものである。 [10] The heavy duty tire according to [9], wherein A in the general formula (I) is a halogen atom, a hydrocarbyloxy group having 1 to 20 carbon atoms or a hydroxy group,
[11] A post-periodic table in which a modified styrene-butadiene copolymer is modified by reacting a compound having a protected amino group and a hydrocarbyloxysilane group in the molecule at the polymerization active terminal of the polymer (long-period type) ) In the presence of a condensation accelerator comprising a compound of an element belonging to any one of Group 3, Group 4, Group 5, Group 12, Group 13, Group 14 and Group 15). 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 titanium-based condensation accelerator is a titanium alkoxide, carboxylate, and acetylacetonate. The heavy duty tire of [13] above, which is at least one selected from complex salts;
[15] The filler, which includes 30 to 120 parts by mass of carbon black and 0 to 40 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 120 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 are 10 to 100% by mass of an amine-based functional group-modified styrene-butadiene copolymer, and 90 to 0% by mass of natural rubber and natural rubber. A heavy duty tire according to any one of the above [1] to [17],
Is to provide.

  INDUSTRIAL APPLICABILITY The present invention can provide a heavy duty tire that has a high balance between the fracture resistance and the rim slipping property of a gum chafer.

First, the modified styrene-butadiene copolymer in the present invention will be described.
[Modified styrene-butadiene copolymer]
The modified styrene-butadiene copolymer (hereinafter sometimes referred to as modified SBR) in the present invention is characterized by being modified with an amine functional group.
In the modified SBR, 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 standpoints of ease of use and suppression of energy loss from the polymer terminal to improve low heat build-up, the polymerization terminal is preferable.
Examples of the amine functional group include a protic amino group and / or a protected amino group. In the modified SBR, those having a hydrocarbyloxysilane group in the polymer together with the protic amino group and / or protected amino group are 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 modification of the above-mentioned protic amino group, protected amino group and hydrocarbyloxysilane group, and base SBR (hereinafter referred to as SBR or unmodified SBR) (hereinafter referred to as modifier) Etc.) will be described in detail later.
As a method for producing a modified SBR of the present invention, a method of producing a modified SBR by obtaining an SBR having an active end and reacting the active end with a modifying agent can be employed.

(Manufacture of SBR)
In the present invention, SBR having an active terminal is obtained by copolymerizing styrene and butadiene, and the production method is not particularly limited, and may be a solution polymerization method, a gas phase polymerization method, or a bulk polymerization method. Either 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 SBR molecule is preferably one selected from alkali metals and alkaline earth metals, more preferably alkali metals, and particularly preferably lithium metal.
In the solution polymerization method, for example, the target polymer can be produced by anionic polymerization of styrene and butadiene using an organic alkali metal compound, particularly a lithium compound as a polymerization initiator.
When the solution polymerization method is used, the monomer concentration in the solvent is preferably 5 to 50% by mass, more preferably 10 to 30% by mass. The amount of styrene is preferably in the range of 20 to 45% by mass with respect to the total amount with butadiene.

  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. SBR in which is a polymerization active site is obtained. When the latter lithium amide compound is used, SBR having a nitrogen-containing group at the polymerization start terminal and the other terminal being a polymerization active site is obtained.

  As the hydrocarbyl lithium, those having a hydrocarbyl group having 2 to 20 carbon atoms are preferable, for example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-octyl lithium, n-decyl. Examples include lithium, phenyl lithium, 2-naphthyl lithium, 2-butyl-phenyl lithium, 4-phenyl-butyl lithium, cyclohexyl lithium, cyclobentyl lithium, and a reactive organism of diisopropenylbenzene and butyl lithium. 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, and lithium disulfide. 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 in advance from a secondary amine and a lithium compound can be used for polymerization, but they 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 SBR by anionic polymerization using the said lithium compound as a polymerization initiator, A conventionally well-known method can be used.
Specifically, in an organic solvent inert to the reaction, for example, a hydrocarbon solvent such as an aliphatic, alicyclic, or aromatic hydrocarbon compound, styrene and butadiene are used as a polymerization initiator, and the lithium compound is used as a polymerization initiator. If desired, the desired SBR can be obtained by anionic polymerization in the presence of the potassium compound or randomizer used.
Thus, content of all the styrene units of SBR obtained is 0.5-55 mass%, and 20-45 are more preferable. The vinyl bond amount in the butadiene portion is preferably 10 mol% or more.
If the amount of vinyl bonds in the butadiene portion is less than 10 mol%, the balance between hysteresis loss and wet skid characteristics deteriorates.
By setting the content of all styrene units in SBR and the vinyl bond content in the butadiene part within the above ranges, the object of the present invention can be effectively achieved.

The randomizer used as desired is control of the microstructure of the SBR, for example, increasing the 1,2 bond of the butadiene moiety, or control of the composition distribution of the monomer unit, for example, randomization of the butadiene unit, styrene unit, etc. It is a compound having the action of 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, 2,2-bis (2-tetrahydrofuryl) -propane, triethylamine, pyridine, N-methylmorpholine, N, N, N ′, Examples thereof include ethers such as N′-tetramethylethylenediamine and 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 particular material being polymerized, the polymerization medium used and the polymerization temperature, but higher pressures can be used if desired, such pressure being a gas that is inert with respect to the polymerization reaction. Can be obtained by an appropriate method such as pressurizing.

In this polymerization, all raw materials involved in the polymerization, such as polymerization initiators, potassium compounds, randomizers, solvents, and monomers, are obtained by removing reaction inhibitors such as water, oxygen, carbon dioxide, and protic compounds. It is desirable to use
In addition, it is preferable that the obtained SBR has a glass transition temperature (Tg) determined by a differential thermal analysis method of −95 ° C. to −15 ° C. By setting the glass transition temperature within the above range, it is possible to suppress the increase in viscosity and obtain an SBR that is easy to handle.

(SBR denaturation)
In the present invention, a predetermined modifier is reacted with the active terminal of the SBR 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.
Examples of the protic amino group and / or protected mino group include —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).
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 SBR preferably has a protic amino group and / or a protected amino group and a hydrocarbyloxysilane group at the same polymerization terminal. 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 To 12 divalent hydrocarbon groups, A represents a reactive group, and f represents 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 a divalent hydrocarbon 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２価の炭化水素基、Ｒ¹³は炭素数１〜１２の２価の炭化水素基、Ａは反応性基、ｆは１〜１０の整数を示す。）

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 divalent hydrocarbon group, R ¹³ is a divalent hydrocarbon 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), specific examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms are, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl. Group, isobutyl group, sec-butyl group, tert-butyl group, various pentyl groups, various hexyl groups, various octyl groups, various decyl groups, various dodecyl groups, various tetradecyl groups, various hexadecyl groups, various octadecyl groups, various icosyl groups , Cyclopentyl group, cyclohexyl group, vinyl group, propenyl group, allyl group, hexenyl group, octenyl group, cyclopentenyl group, cyclohexenyl group, phenyl group, tolyl group, xylyl group, naphthyl group, benzyl group, phenethyl group, A naphthylmethyl group etc. are mentioned. Of these, a methyl group having 1 to 4 carbon atoms, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and the like are preferable. A butyl group is more preferred.
Examples of the divalent hydrocarbon group having 1 to 12 carbon atoms include an alkylene group having 1 to 12 carbon atoms, an arylene group having 6 to 12 carbon atoms, and an arylene alkylene group having 7 to 12 carbon atoms.
The alkylene group having 1 to 12 carbon atoms may be linear or branched, and specifically includes a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a hexamethylene group, and an octamethylene group. , Linear alkylene group such as decamethylene group, propylene group, isopropylene group, isobutylene group, 2-methyltrimethylene group, isopentylene group, isohexylene group, isooctylene group, 2-ethylhexylene group, isodecylene group, etc. A branched alkylene group may be mentioned.
Examples of the arylene group having 6 to 12 carbon atoms include phenylene group, methylphenylene group, dimethylphenylene group, and naphthylene group. Examples of the arylene alkylene group having 7 to 12 carbon atoms include phenylenemethylene group and phenyleneethylene. Group, xylylene group and the like. Among them, an alkylene group having 1 to 4 carbon atoms is preferable, and a trimethylene group is particularly preferable.
The reactive group of A is preferably a halogen atom, a hydrocarbyloxy group having 1 to 20 carbon atoms, or a hydroxy group. Examples of the halogen atom include fluorine, chlorine, bromine, and iodine. Among them, chlorine is preferable.
Examples of the hydrocarbyloxy group having 1 to 20 carbon atoms include an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, and an aralkyloxy group having 7 to 20 carbon atoms.
Examples of the alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, n-propoxy group, n-butoxy group, isobutoxy group, sec-butoxy group, tert-butoxy group, various hexoxy groups, various octoxy groups, and various types. Examples include decyloxy groups, various dodecyloxy groups, various tetradecyloxy groups, various hexadecyloxy groups, various octadecyloxy groups, and various icosyloxy groups. Examples of the aryloxy group having 6 to 20 carbon atoms include phenoxy group, methylphenoxy group, dimethylphenoxy group, and naphthoxy group. Examples of the aralkyloxy group having 7 to 20 carbon atoms include benzyloxy group, phenethyloxy group, A naphthyl methoxy group etc. are mentioned. Among these, 1-4 alkoxy groups are preferable, and an ethoxy group is particularly preferable.
In addition, the hydroxy group bonded to the silicon atom obtained by hydrolysis in advance has a higher reactivity with the silica when reacting with the reinforcing filler, particularly silica, than the alkoxy group, and the rubber composition contains There is a great effect that the dispersibility of silica is improved and the low heat build-up 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 other reactive groups include groups containing a carbonyl group, an acid anhydride residue, each dihydroimidazolinyl group, an N-methylpyrrolidonyl group, an isocyanate group, and the like.
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. Examples of the 4- to 7-membered ring include those having a methylene group having 4 to 7 carbon atoms.

Examples of the compound containing a protected primary amino group and a bifunctional silicon atom having at least an alkoxy group bonded to a silicon atom 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 Examples thereof include -1-aza-2-silacyclopentane.
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 alone or in combination of two or more. 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 with the denaturing agent, the amount of the denaturing agent is preferably 0.5 to 200 mmol / kg · SBR. The content is more preferably 1 to 100 mmol / kg · SBR, and particularly preferably 2 to 50 mmol / kg · SBR. Here, SBR means the mass of only a polymer that does not contain 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, it is preferable to use a condensation accelerator in order to accelerate the condensation reaction involving the alkoxysilane compound having a protected primary 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 condensation accelerators include tetrakis (2-ethyl-1,3-hexanediolato) titanium, tetrakis (2-methyl-1,3-hexanediolato) titanium, tetrakis (2-propyl-1,3). -Hexanediolato) titanium, tetrakis (2-butyl-1,3-hexanediolato) titanium, tetrakis (1,3-hexanediolato) titanium, tetrakis (1,3-pentanediolato) titanium, tetrakis (2 -Methyl-1,3-pentanediolato) titanium, tetrakis (2-ethyl-1,3-pentanediolato) titanium, tetrakis (2-propyl-1,3-pentanediolato) titanium, tetrakis (2-butyl) -1,3-pentanediolato) titanium, tetrakis (1,3-heptanediolato) titanium, tetrakis (2-methyl-1,3- Butanediolato) titanium, tetrakis (2-ethyl-1,3-heptanediolato) titanium, tetrakis (2-propyl-1,3-heptanediolato) titanium, tetrakis (2-butyl-1,3-heptanediolato) titanium, tetrakis (2- Ethylhexoxy) titanium, tetramethoxy titanium, tetraethoxy titanium, tetra-n-propoxy titanium, tetraisopropoxy titanium, tetra-n-butoxy titanium, tetra-n-butoxy titanium oligomer, tetraisobutoxy titanium, tetra-sec-butoxy titanium , Tetra-tert-butoxytitanium, bis (oleate) bis (2-ethylhexanoate) titanium, titanium dipropoxybis (triethanolamate), titanium dibutoxybis (triethanolamate), tita Tributoxy systemate, titanium tripropoxy systemate, titanium tripropoxyacetylacetonate, titanium dipropoxybis (acetylacetonate), titanium tripropoxy (ethylacetoacetate), titanium propoxyacetylacetonatebis (ethylacetoacetate), titanium Tributoxyacetylacetonate, titanium dibutoxybis (acetylacetonate), titanium tributoxyethylacetoacetate, titaniumbutoxyacetylacetonatebis (ethylacetoacetate), titanium tetrakis (acetylacetonate), titanium diacetylacetonatebis (ethyl) Acetoacetate), bis (2-ethylhexanoate) titanium oxide, bis (laurate) titanium oxide, bis (naphthate) Titanium oxide, bis (stearate) titanium oxide, bis (oleate) titanium oxide, bis (linoleate) titanium oxide, tetrakis (2-ethylhexanoate) titanium, tetrakis (laurate) titanium, tetrakis (naphthate) titanium, tetrakis ( Stearate) titanium, tetrakis (oleate) titanium, tetrakis (linoleate) titanium, titanium di-n-butoxide (bis-2,4-pentanedionate), titanium oxide bis (stearate), titanium oxide bis (tetramethylheptanedio) Nate), titanium oxide bis (pentanedionate), titanium tetra (lactate) and the like. Among these, tetrakis (2-ethyl-1,3-hexanediolato) titanium, tetrakis (2-ethylhexoxy) titanium, and titanium di-n-butoxide (bis-2,4-pentanedionate) are preferable.

  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 efficiently advanced and completed, and the deterioration of the quality due to the aging reaction of the polymer due to the change over time of the resulting modified conjugated diene polymer can be suppressed. Can do.

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 primary amino group derived from the modifier of the modified conjugated diene polymer of the present invention is generated by performing a 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 protecting group on the primary amino group is converted to a free primary amino group by hydrolysis. By removing the solvent from this, a modified conjugated diene polymer having a primary amino group can be obtained. In addition, the deprotection treatment of the protected primary amino group derived from the modifier can be performed as necessary in any step from the step including the condensation treatment to the solvent removal to the dry polymer.

The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the modified SBR obtained in the present invention is preferably 10 to 150, more preferably _{15 to} 100. 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 SBR in the present invention has a protic amino group and / or a protected amino group, preferably these amine functional groups and a hydrocarbyloxysilane group, in the polymer. The amino group dissociating group has a good interaction with carbon black and silica, while the hydrocarbyloxysilane group has a particularly excellent interaction with silica.
The rubber composition containing the modified SBR can provide a heavy-duty tire that has excellent fracture characteristics and wear characteristics and suppresses an increase in the temperature of the gum chafer during traveling.

Next, the rubber composition used for the gum chafer 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 100% by mass of an amine functional group-modified SBR and natural rubber.
(Rubber component)
The rubber composition used for the gum chafer of the heavy duty tire of the present invention is required to contain at least 10% by mass of the modified SBR as a rubber component. The preferable content of the modified SBR in the rubber component is 40% by mass or more. By setting the modified SBR in the rubber component in the above range, a rubber composition having desired physical properties can be obtained.
This modified SBR may be used singly or in combination of two or more. In addition, other rubber components used in combination with the modified SBR and natural rubber within the scope of the present invention include synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-α-olefin copolymer rubber, ethylene-α- Examples thereof include olefin-diene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chlorobrene rubber, halogenated ptyl rubber, and mixtures thereof. 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. Of these, natural rubber and synthetic isoprene rubber are preferable, and natural rubber is particularly preferable.

(Filler)
In the rubber composition used for the gum chafer 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-LS, HAF, HAF-HS can be appropriately selected and used.

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 “Nipsea AQ” manufactured by Tosoh Silica Co., Ltd. and BET 195 m ² / g.
As the filler, carbon black 30 ~ per 100 parts by mass of the rubber component
While including 120 mass parts and 0-40 mass parts of silica, it is preferable that the total amount of carbon black and silica is 30-120 mass parts, More preferably, it is 40-100 mass parts. By setting the amount of the filler within the above range, the fracture 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- Kuta Neu Lucio ethyltrimethoxysilane, 2- deca Neu thio ethyltrimethoxysilane, and the like of 2-lauroyl thio ethyltrimethoxysilane.

By using such a silane coupling agent, the rubber composition in the present invention can be kneaded for a long time by increasing the time until the occurrence of burns due to a decrease in the viscosity of the unvulcanized rubber. While being excellent in workability at the time of kneading processing of the rubber composition, it is possible to reduce the hysteresis loss by improving the dispersion of silica into the rubber component and improving the reactivity between silica and the polymer. Utilizing this improvement, it becomes possible to increase the blending amount of the reinforcing filler, and as a result, a heavy-duty tire with good wear resistance can be obtained.
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 used as a silane coupling agent according to the present invention, the rubber composition has a low unvulcanized viscosity and a high silica dispersibility, and when used as a tire gum chafer member, it has fracture resistance. It is high and suppresses the temperature rise of the running gum chafer.

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-dimethylthiocarbamoyl Tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxy Silylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyltetra Sulfide, dimethoxymethylsilylpropylbenzothiazolyl tetrasulfide, etc. are mentioned. Among these, bis (3-trieth Shi silyl propyl) 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 sulfur content with respect to 100 mass parts of (A) 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 fracture strength, wear resistance, and low heat build-up of the vulcanized rubber may be reduced. If the amount exceeds 10.0 parts by mass, 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 gum chafer.

[Heavy tires]
The heavy duty tire of the present invention is produced by a usual method using the rubber composition. That is, if necessary, the rubber composition containing various chemicals as described above is processed into a gum chafer at an unvulcanized stage, and pasted and molded by a normal method on a tire molding machine, and the raw tire Is formed. The green tire is heated and pressed in a vulcanizer to obtain a tire.
Here, the bead part which concerns on a gum chafer is demonstrated in detail using FIG.
FIG. 1 is a diagram showing a cross section of a bead portion only on one side according to an embodiment of a heavy duty tire of the present invention.
1. 1 is a bead core, 2 is a carcass, 3 is a wire chafer, 4 is a gum chafer, 5 is an inner liner, 6 is a bead toe rubber, P is a bead toe part, and L is a bead base part.
The heavy duty tire of the present invention thus obtained can greatly improve the fracture resistance and rim slip of the 4-gum chafer.

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 unmodified or modified SBR >>
<Microstructure analysis method>
The vinyl bond content (%) was measured by an infrared method (Morero method).
<Bound styrene content (mass% in polymer)>
It was determined by 270 MHz ¹ H-NMR.
<Measurement of number average molecular weight (Mn), weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn)>
It measured using GPC [The Tosoh make, HLC-8020] using the refractometer as a detector, and showed it by polystyrene conversion which used the monodisperse polystyrene as a standard. The column is GMHXL [manufactured by Tosoh] and the eluent is tetrahydrofuran.
<Measurement of Mooney viscosity (ML _{1 + 4} , 100 ° C.)>
According to JIS K6300, it was determined at a temperature of 100 ° C., L overnight, preheating 1 minute, rotor operating time 4 minutes.

<< Evaluation of rubber composition >>
According to the blending composition described in Table 1, the physical properties of the vulcanizates obtained by kneading were evaluated. Regarding the evaluation, the following tensile stress at 100% elongation, Tan δ, was evaluated.
(1). Measurement of tensile stress at 100% elongation (100% Mod.) It was based on JIS K6301 1995. The measurement results are shown in Table 1. The comparative example 2 was set to 100 and expressed as an index. The larger value indicates Mod. Is high.
(2). Measurement of tan δ The test piece of the obtained vulcanizate was measured using a viscoelasticity measuring device (a spectrometer manufactured by Toyo Seiki Co., Ltd.) under the conditions of a temperature of 25 ° C., a strain of 2%, and a frequency of 52 Hz. The measurement results are shown in Table 1. The comparative example 2 was set to 100 and expressed as an index. A lower value indicates lower heat build-up.

<< Evaluation of tire performance >>
(1). Rim slip evaluation In an off-the-road tire of size 26.5R25, it is assembled to a 5 ° deep rim with TRK standards, and a filling air pressure of 60 kPa, and a load of 150 kN is applied to the tire wheel in a static load test. The tresso road surface is pressed against the plate, and the plate is moved in a state where the tire is braked. At this time, the amount of rim slip generated in the bead portion is measured, and the result is indicated by an index.
The larger the index value, the better the result. The conventional tire of Comparative Example 2 has a structure in which hard rubber is disposed on the bead toe side of the wire chafer.

Production Example 1 Primary amino-modified styrene-butadiene rubber <Synthesis of modifier>
Synthesis Example 1: Synthesis of N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane 36 g of 3-aminopropylmethyldiethoxysilane as an aminosilane moiety in 400 ml of dichloromethane solvent in a glass flask equipped with a stirrer under nitrogen atmosphere After addition of (Gelest), 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, and then the solvent was removed by applying the reaction solution to an evaporator. Was removed by distillation under reduced pressure under the condition of 665 Pa to obtain 40 g of N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane as a 130-135 ° C. fraction. .

<Synthesis of primary amine-modified styrene-butadiene rubber>
An autoclave reactor with an internal volume of 5 liters purged with nitrogen was charged with 2,750 g of cyclohexane, 41.3 g of tetrahydrofuran, 125 g of styrene, and 375 g of 1,3-butadiene. After adjusting the temperature of the reactor contents to 10 ° C., 215 mg of n-butyllithium was added to initiate polymerization. The polymerization was carried out under adiabatic conditions and the maximum temperature reached 85 ° C.
When the polymerization conversion rate reached 99%, 10 g of butadiene was added, and polymerization was further performed for 5 minutes. The polymer solution from the reactor was sampled in a small amount in 30 g of a cyclohexane solution added with 1 g of methanol, and then 1129 mg of N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane obtained in Synthesis Example 1 was added to carry out the modification reaction. I went for 15 minutes. Thereafter, 8.11 g of tetrakis (2-ethyl-1,3-hexanediolato) titanium as a condensation accelerator was added, and the mixture was further stirred for 15 minutes to conduct a condensation reaction. Finally, 2.6-di-tert-butyl-p-cresol was added to the polymer solution after the reaction. Next, the solvent was removed by steam stripping and the protected primary amino group was deprotected, and the rubber was dried with a rip roll adjusted to 110 ° C. to obtain a primary amine-modified styrene-butadiene rubber. The obtained primary amine-modified styrene-butadiene rubber has a bound styrene content of 24.5% by mass, a vinyl content of the conjugated diene part of 56 mol%, and a Mooney viscosity of 32.

Examples 1-4 and Comparative Examples 1-2
Six types of rubber compositions having the compounding compositions shown in Table 1 were prepared, and the tensile stress and Tan δ at 100% elongation were measured for each vulcanized sample. Was evaluated.

［注］
＊１．未変性スチレン−ブタジエンゴム；製造例１の未変性の状態のものを用いた
＊２．変性スチレン−ブタジエンゴム：製造例１の第一アミン変性スチレン−ブタジエンゴムを 用いた
＊３．カーボンブラック：カーボンブラックＡ：Ｎ３３０ 旭カーボン社製「♯７０」
＊４．ノボラック型フェノール樹脂：住友ベークライト社製、「ＰＲ５０２３５」
＊５．メラミン樹脂：ＡＭＥＲＩＣＡＮ ＣＹＡＮＡＭＩＤ社製、「ＣＹＲＥＺ９６４」
＊６．老化防止剤６ＰＰＤ：大内新興化学工業社製「ノクセラー６Ｃ」
＊７．加硫促進剤ＣＺ：大内新興化学工業社製「ノクセラーＣＺ」

[note]
* 1. Unmodified styrene-butadiene rubber: used in the unmodified state of Production Example 1 * 2. Modified styrene-butadiene rubber: The primary amine-modified styrene-butadiene rubber of Production Example 1 was used. * 3. Carbon Black: Carbon Black A: N330 “# 70” manufactured by Asahi Carbon Corporation
* 4. Novolac type phenolic resin: “PR50235” manufactured by Sumitomo Bakelite Co., Ltd.
* 5. Melamine resin: “CYREZ964” manufactured by AMERICA CYANAMID
* 6. Anti-aging agent 6PPD: “Noxeller 6C” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
* 7. Vulcanization accelerator CZ: “Noxeller CZ” manufactured by Ouchi Shinsei Chemical Co., Ltd.

  The heavy-duty tire of the present invention is a tire in which the fracture resistance and rim slip properties of a gum chafer are highly balanced, and can be suitably applied to trucks, buses, off-the-road tires (OR tires), and the like.

It is the figure which showed the cross section of the bead part only about one side about embodiment of the tire for heavy loads of this invention.

Explanation of symbols

1. 1. Bead core Carcass 3. 3. Wire chafer Gum chafer 5. Inner liner6. Bead toe rubber P. Bead toe L. Bead base

Claims (18)

  A rubber composition containing a rubber component and a filler, and the rubber component containing 10 to 100% by mass of an amine-based functional group-modified styrene-butadiene copolymer and natural rubber is used for a gum chafer. Features heavy duty tires.   The heavy duty tire according to claim 1, wherein the amine functional group-modified styrene-butadiene copolymer has a protic amino group and / or a protected amino group as an amine functional group.   The heavy duty tire according to claim 2, wherein the amine-based functional group-modified styrene-butadiene copolymer further has a hydrocarbyloxysilane group.   The heavy-duty tire according to claim 3, wherein the amine functional group-modified styrene-butadiene copolymer has a protic amino group and / or a protected amino group and a hydrocarbyloxysilane group at a polymerization terminal.   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.   An amine functional group-modified styrene-butadiene copolymer is modified by reacting a compound having a protected amino group and a hydrocarbyloxysilane group in the molecule at the polymerization active terminal of the styrene-butadiene copolymer. The heavy-duty tire according to any one of claims 2 to 6.   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 divalent hydrocarbon group of ˜12, A is a reactive group, f is an integer of 1 to 10, and a silicon compound represented by the general formula (II)

(Wherein R ^{7 to} R ¹¹ each independently represents a hydrocarbon group having 1 to 20 carbon atoms, and R ¹² represents a divalent hydrocarbon group having 1 to 12 carbon atoms) 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 To 12 divalent hydrocarbon groups, R ¹³ is a divalent hydrocarbon 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 claim 8, which is at least one selected.   The heavy-duty tire according to claim 9, wherein A in the general formula (I) is a halogen atom, a hydrocarbyloxy group having 1 to 20 carbon atoms, or a hydroxy group.   The modified styrene-butadiene copolymer is modified by reacting and modifying a compound having a protected amino group and a hydrocarbyloxysilane group in the molecule at the polymerization active terminal of the polymer. 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 12, group 13, group 14 and group 15, subjected to a condensation reaction involving the compound The heavy-duty tire according to any one of claims 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 tire for heavy loads 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. As the filler, carbon black 30 ~ per 100 parts by mass of the rubber component
The heavy-duty tire according to any one of claims 1 to 14, which includes 120 parts by mass and 0 to 40 parts by mass of silica, and a total amount of carbon black and silica is 30 to 120 parts by mass.   The heavy-duty tire according to claim 15, containing 2 to 20 mass% of a silane coupling agent with respect to the silica. 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. 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 is composed of 10 to 100% by mass of an amine-based functional group-modified styrene-butadiene copolymer and 90 to 0% by mass of natural rubber and natural rubber.

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