JP2009262835A - Tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire, especially a pneumatic tire for a heavy load, drastically improved in ply adhesion durability by suppressing a rise in the temperature of the tire during travel without losing the crack resistance of a rubber. <P>SOLUTION: This invention relates to the tire, especially the pneumatic tire for a heavy load, using a rubber composition comprising (A) a rubber composition including an amine system functional group modified polybutadiene rubber with an amino group protected by a protonic amino group and/or a separable group, and (B) a reinforcing filler, for a belt under cushion rubber. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention uses a rubber composition containing a specific modified polybutadiene rubber as a rubber component for a belt undercushion rubber, thereby suppressing an increase in tire temperature during running without impairing the crack resistance of the rubber. More particularly, the present invention relates to a heavy-duty pneumatic tire.

  Off-the-road pneumatic tires for large construction vehicles and heavy duty pneumatic tires such as truck and bus pneumatic tires are generally treads and tread belts interposed between the tread and carcass. Have A belt undercushion formed of an elastomer material having a relatively low modulus on the inner side of the belt (an elastomer between the belt and the carcass, and in some cases with an integrated shoulder and from the belt end portion to the central portion) Material). This cushion functions as a shock absorber between the relative lateral edges of the tread belt and the body ply, and is inserted to increase the wear resistance of the tread and the life of the carcass. The cushion has a function of distributing the internal stress of the carcass over the entire tread surface.

In recent years, in addition to the belt undercushion, belt cushion rubber to reduce the distortion and end of the belt end, which is likely to cause failure, in heavy duty pneumatic tires used in trucks and buses, etc. It has been proposed to arrange a strip (particularly near the shoulder) (see, for example, Patent Document 1).
However, even if such a structure is proposed, it is desired to improve the essential rubber characteristics of the belt undercushion. That is, pneumatic tires for heavy loads such as trucks and buses have a belt undercushion as described above in order to reduce the distortion and temperature at the belt end, which is likely to cause failure, and to obtain high tire durability. It is desirable to place a low exothermic rubber.

JP 2002-36815 A

  The present invention has been made under such circumstances, and by using a specific rubber composition for a belt undercushion rubber, an increase in tire temperature during running is suppressed without impairing the crack resistance of the rubber. Thus, an object of the present invention is to provide a tire having a significantly improved ply adhesion durability, particularly a heavy duty pneumatic tire.

  As a result of intensive studies to achieve the above object, the present inventor has obtained a rubber composition containing a rubber component containing 10% by mass or more of an amine-based functional group-modified polybutadiene rubber and a reinforcing filler as a belt undercoat. It discovered that the objective could be achieved by using for cushion rubber. The present invention has been completed based on such findings.

That is, the present invention
[1] A rubber containing (A) a rubber component containing an amine-based functional group-modified polybutadiene rubber having an amino group protected with a protic amino group and / or a detachable group, and (B) a reinforcing filler. A tire characterized by using the composition as a belt undercushion rubber;
[2] The tire according to [1], wherein the amine functional group-modified polybutadiene rubber further has a silicon atom,
[3] The tire according to [2], wherein the silicon atom is a silicon atom bonded to a hydrocarbyloxy group and / or a hydroxy group.
[4] The amine functional group-modified polybutadiene rubber has a silicon atom in which an amino group protected with a protic amino group and / or a detachable group, and a hydrocarbyloxy group and / or a hydroxy group are bonded to the polymerization terminal. The tire according to [3] above,
[5] In the above [4], an amino group protected with a protic amino group and / or a detachable group and a silicon atom bonded to a hydrocarbyloxy group and / or a hydroxy group at the same polymerization active terminal Listed tires,
[6] The tire according to any one of [1] to [5], wherein the protic amino group is at least one selected from a primary amino group, a secondary amino group, and salts thereof.
[7] Any one of [1] to [5] above, wherein the amino group protected by the detachable group is an N, N-bis (trimethylsilyl) amino group and / or an N- (trimethylsilyl) imino group. Listed tires,

[8] The amine-based functional group-modified polybutadiene rubber has a primary amino group and / or a secondary amino group-containing group protected with a detachable group as a modifier at the active terminal of the polybutadiene having an active terminal. The tire according to any one of the above [1] to [7], wherein the hydrocarbyloxy group is formed by reacting and modifying a silane compound formed by bonding to the same silicon atom.
[9] The modifier is represented by the general formula (1)

[Wherein Y is a hydrocarbyloxy group, R ¹ is a monovalent hydrocarbon group, R ² is a divalent hydrocarbon group, X is a primary amino group and / or a secondary amino group protected with a detachable group. Represents a group, and m represents an integer of 1 to 3. However, active protons and onium salts are not included in the molecule. ]
The tire according to [8] above, which is a silane compound represented by:
[10] In the general formula (1), Y is a hydrocarbyloxy group having 1 to 18 carbon atoms, R ¹ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, and R ² is a divalent hydrocarbon having 1 to 20 carbon atoms. The tire according to [9] above, which is a hydrocarbon group,
[11] The tire according to [9] or [10], wherein in X in the general formula (1), the detachable group protecting the primary amino group or the secondary amino group is a trimethylsilyl group,
[12] The modifier is represented by the general formula (2)

Wherein R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{5 to} R ⁷ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁸ is a carbon number 1 A silane compound represented by formula (3): a divalent hydrocarbon group of -12, A is a reactive group, and f is an integer of 1-10.

(Wherein R ^{9 to} R ¹³ are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ¹⁴ is a divalent hydrocarbon group having 1 to 12 carbon atoms, and n is 1 or 2). Silane compounds represented by the general formula (4)

Wherein R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{5 to} R ⁷ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁸ is a carbon number 1 -12 divalent hydrocarbon group, R ¹⁵ 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 tire according to [8], selected from among the above,
[13] The tire according to [12], wherein A in the general formula (2) and the general formula (4) is a halogen atom or a hydrocarbyloxy group having 1 to 20 carbon atoms.
[14] The above [8] to [13], wherein the modifier is N, N-bis (trimethylsilyl) aminopropyl (methyl) dimethoxysilane or N, N-bis (trimethylsilyl) aminopropyl (methyl) diethoxysilane. A tire according to any one of
[15] The modifier is 1-trimethylsilyl-2-ethoxy-2-methyl-1-aza-2-silacyclopentane, 1-trimethylsilyl-2-methoxy-2-methyl-1-aza-2-silacyclo The above-mentioned [12], which is pentane, 1-trimethylsilyl-2,2-diethoxy-1-aza-2-silacyclopentane, or 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane. tire,
[16] The polybutadiene having an active end is obtained by anionic polymerization of 1,3-butadiene using an organic alkali metal compound as a polymerization initiator, according to any one of the above [8] to [15]. Tires,
[17] The amine functional group-modified polybutadiene rubber has a primary amino group and / or a secondary amino-containing group protected with a detachable group as a modifier at the active terminal of the polybutadiene having an active terminal, and hydrocarbyl. After reacting and modifying a silane compound formed by bonding an oxy group to the same silicon atom, it belongs to any one of Groups 4, 13, 14, and 15 of the periodic table (long-period type) The tire according to any one of the above [8] to [16], which is obtained by performing a condensation reaction involving the silane compound in the presence of a condensation accelerator composed of an elemental compound,
[18] The tire according to [17], wherein the condensation accelerator is an alkoxide, carboxylate, or acetylacetonate complex of titanium, zirconium, bismuth or aluminum.
[19] The above, wherein (A) the rubber component contains (a) 10 to 100% by mass of an amine functional group-modified polybutadiene rubber and (b) 90 to 0% by mass of natural rubber and / or synthetic conjugated diene rubber. 1] to [18], the tire according to any one of
[20] The tire according to [19], wherein the component (b) is natural rubber,
[21] The reinforcing filler of component (B) is carbon black and / or silica, and the content thereof is 30 to 65 parts by mass with respect to 100 parts by mass of (A) rubber component. 1] to [20], the tire according to any one of
[22] The tire according to [21], including a silane coupling agent in a proportion of 2 to 20% by mass relative to the silica.
[23] The tire according to any one of [1] to [22], which is a heavy-duty pneumatic tire, and [24] the above-mentioned [23], which is for off-the-road or truck / bus use. Tires are provided.

  According to the present invention, by using a rubber composition containing a specific modified polybutadiene rubber as a rubber component for a belt undercushion rubber, an increase in tire temperature during running is suppressed without impairing the crack resistance of the rubber. Thus, it is possible to provide a tire, particularly a heavy-duty pneumatic tire, with significantly improved ply adhesion durability.

The tire of the present invention comprises (A) a rubber component containing an amine-based functional group-modified polybutadiene rubber having an amino group protected with a protic amino group and / or a detachable group, and (B) a reinforcing filler. The rubber composition is used for a belt undercushion rubber.
The belt undercushion rubber will be described in detail in the description of a tire described later, particularly a heavy load pneumatic tire.
First, the rubber composition used for the tire of the present invention will be described.
((A) rubber component)
In the rubber composition used for the belt undercushion rubber according to the present invention (hereinafter sometimes simply referred to as the rubber composition according to the present invention), 10 mass of amine functional group-modified polybutadiene rubber is used as component (A). It is preferable to use a rubber component containing at least%.

<Amine-based functional group-modified polybutadiene rubber>
In the present invention, the amine functional group-modified polybutadiene rubber used for the rubber component (A) includes polybutadiene rubber having an amino group protected with a protic amino group and / or a detachable group in the molecule. Preferably, polybutadiene rubber having a silicon atom can be mentioned. Here, as a silicon atom, the silicon atom which the hydrocarbyl oxy group and / or the hydroxy group couple | bonded is preferable.
Such a modified functional group may be present at any of the polymerization initiation terminal, the side chain, and the polymerization active terminal of the polybutadiene rubber. In the present invention, a protic amino group is present at the polymerization terminal, particularly at the same polymerization active terminal. It is particularly preferable to have an amino group protected with a group and / or a detachable group and a silicon atom to which a hydrocarbyloxy group and / or a hydroxy group are bonded.

Examples of the protic amino group include at least one selected from a primary amino group, a secondary amino group, and salts thereof.
On the other hand, examples of the amino group protected with a detachable group include N, N-bis (trihydrocarbylsilyl) amino group and N- (trihydrocarbylsilyl) imino group. Preferably, the hydrocarbyl group is carbon. The trialkylsilyl group which is a C1-C10 alkyl group can be mentioned, Especially preferably, a trimethylsilyl group can be mentioned.
Examples of primary amino groups protected with a detachable group include N, N-bis (trimethylsilyl) amino groups, and examples of secondary amino groups protected with a detachable group include N A-(trimethylsilyl) imino group can be mentioned. The N- (trimethylsilyl) imino group-containing group may be an acyclic imine residue or a cyclic imine residue.

The amine-based functional group-modified polybutadiene rubber according to the present invention includes a primary amino group and / or a secondary amino group-containing group protected with a detachable group as a modifier at the active end of a polybutadiene having an active end, and hydrocarbyl. It is preferable that the oxy group is formed by reacting and modifying a silane compound formed by bonding to the same silicon atom.
<< Polybutadiene having active ends >>
In order to effectively perform the modification reaction, the polybutadiene having an active terminal is preferably obtained by anionic polymerization of 1,3-butadiene using an organic alkali metal compound as a polymerization initiator.
As the anionic polymerization method, a solution polymerization method is particularly preferable, and the polymerization mode may be either a batch type or a continuous type. As the organic alkali metal compound, a lithium compound is particularly preferable.
The 1,3-butadiene concentration in the solvent in the solution polymerization method 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. A polybutadiene having a polymerization active site is obtained. When the latter lithium amide compound is used, a polybutadiene 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, cyclobenchyllithium, 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, and lithium disulfide. Heptylamide, lithium dihexylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium-N-methylpiverazide, lithium ethylpropylamide, lithium ethylbutyramide, lithium ethylbenzylamide, lithium methylphenethylamide, etc. Is mentioned. Among these, from the viewpoint of the interaction effect on carbon black and the ability of initiating polymerization, cyclic lithium amides such as lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, 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 secondary amines and lithium compounds can be used for polymerization, but can also be prepared in the polymerization system (in-situ). The amount of the polymerization initiator used is preferably selected in the range of 0.2 to 20 mmol per 100 g of monomer.

There is no restriction | limiting in particular as a method of manufacturing a polybutadiene 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, 1,3-butadiene is used as the polymerization initiator. If desired, polybutadiene having the desired active terminal 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 and trans-2. -Butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene and the like. These may be used alone or in combination of two or more.

The randomizer used as desired has functions such as control of the polybutadiene microstructure, for example, control of 1,2 bonds. 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.
These randomizers may be used individually by 1 type, and may be used in combination of 2 or more type. 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, randomizers, solvents, monomers, etc. should be used after removal of reaction inhibitors such as water, oxygen, carbon dioxide, and protic compounds. Is desirable.

《Modifier》
In the present invention, as a modifier to be reacted with the active end of the polybutadiene having an active end obtained as described above, it contains a primary amino group and / or a secondary amino group protected with a detachable group. A silane compound in which a group and a hydrocarbyloxy group are bonded to the same silicon atom is preferably used.
As such a modifier, a silane compound I represented by the following general formula (1) or a silane compound selected from the general formula (2), the general formula (3), and the general formula (4) II can be preferably mentioned.

(1) Silane compound I
As a modifier represented by the silane compound I, the following general formula (1)

A silane compound having a structure represented by the above and / or a partial condensate thereof can be used.
In the general formula (1), Y is a hydrocarbyloxy group, R ¹ is a monovalent hydrocarbon group, R ² is a divalent hydrocarbon group, X is a primary amino group protected with a detachable group, and / or Or a secondary amino group is shown, m shows the integer of 1-3. However, active protons and onium salts are not included in the molecule.
The hydrocarbyloxy group represented by Y is preferably one having 1 to 18 carbon atoms, such as an alkoxy group having 1 to 18 carbon atoms, an alkenyloxy group having 2 to 18 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, or a carbon number. Examples thereof include 7 to 18 aralkyloxy groups, and among these, an alkoxy group having 1 to 10 carbon atoms is preferable from the viewpoint of having good reactivity. The alkyl group constituting the alkoxy group may be linear, branched or cyclic. Examples of such an alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, various pentoxy groups, various hexoxy groups, Examples thereof include various heptoxy groups, various octoxy groups, various decyloxy groups, cyclopentyloxy groups, cyclohexyloxy groups, etc. Among these, alkoxy groups having 1 to 6 carbon atoms are preferable from the viewpoint of reactivity, and in particular, methoxy And ethoxy groups are preferred.
m represents an integer of 1 to 3, and when there are a plurality of Y, the plurality of Y may be the same or different.

The monovalent hydrocarbon group represented by R ¹ is preferably one having 1 to 18 carbon atoms, such as an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, or an aryl having 6 to 18 carbon atoms. Group, an aralkyl group having 7 to 18 carbon atoms, and the like. Among these, from the viewpoint of the reactivity and performance of the modifier, an alkyl group having 1 to 18 carbon atoms is preferable, and an alkyl group having 1 to 10 carbon atoms is preferred. Groups are more preferred. The alkyl group may be linear, branched, or cyclic. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert. -A butyl group, various pentyl groups, various hexyl groups, various octyl groups, various decyl groups, a cyclopentyl group, a cyclohexyl group, etc. can be mentioned. Among these, from the viewpoint of the reactivity and performance of the modifier, an alkyl group having 1 to 6 carbon atoms is preferable, and a methyl group is particularly preferable.

The divalent hydrocarbon group represented by R ² is preferably one having 1 to 20 carbon atoms, more preferably an alkanediyl group having 1 to 20 carbon atoms from the viewpoint of the performance of the modifier, and 2 to 10 carbon atoms. The alkanediyl group is more preferable, and the alkanediyl group having 2 to 6 carbon atoms is particularly preferable.
The alkanediyl group having 2 to 6 carbon atoms may be linear or branched. For example, ethylene group, 1,3-propanediyl group, 1,2-propanediyl group, various butanediyl groups, various types A pentanediyl group, various hexanediyl groups, etc. can be mentioned, but among these, linear ones such as ethylene group, 1,3-propanediyl group, 1,4-butanediyl group, 1,5-pentanediyl group 1,6-hexanediyl group, etc., and 1,3-propanediyl group is particularly preferable.

X is a primary amino group and / or a secondary amino group protected with a detachable group, and examples of the detachable group include a trihydrocarbylsilyl group, and preferably the hydrocarbyl group has 1 to 1 carbon atoms. The trialkylsilyl group which is 10 alkyl groups can be mentioned, Especially preferably, a trimethylsilyl group can be mentioned.
Examples of primary amino groups protected with a detachable group include N, N-bis (trimethylsilyl) amino groups, and examples of secondary amino groups protected with a detachable group include N A-(trimethylsilyl) imino group can be mentioned. The N- (trimethylsilyl) imino group-containing group may be an acyclic imine residue or a cyclic imine residue.
Examples of the cyclic imine residue protected with a detachable group include N- (trimethylsilyl) hexamethyleneimine residue, N- (trimethylsilyl) pyrrolidine residue, N- (trimethylsilyl) piperidine residue, N- (trimethylsilyl) Examples include heptamethyleneimine residue, N- (trimethylsilyl) dodecamethylene residue, N- (trimethylsilyl) imidazole residue, N- (trimethylsilyl) -4,5-dihydroimidazole residue.

In the present invention, as the silane compound represented by the general formula (1), a bifunctional hydrocarbyloxysilane compound in which m is 2 is preferable. By using such a bifunctional silane compound as a modifier, the resulting modified polybutadiene rubber can introduce a modified terminal with high efficiency, and has a large interaction with an inorganic filler such as silica.
A partial condensate can be used as the silane compound represented by the general formula (1). Here, the partial condensate means a product in which a part (not all) of the SiOR groups of the hydrocarbyloxysilane compound are bonded by SiOSi by condensation.

  As the silane compound represented by the general formula (1), for example, when X has a primary amino group protected with a detachable group, as a specific example, N, N-bis (trimethylsilyl) aminopropyl (methyl) ) Dimethoxysilane, N, N-bis (trimethylsilyl) aminopropyl (methyl) diethoxysilane, N, N-bis (trimethylsilyl) aminopropyl (methyl) dipropoxysilane, N, N-bis (trimethylsilyl) aminopropyl (ethyl) ) Dimethoxysilane, N, N-bis (trimethylsilyl) aminopropyl (ethyl) diethoxysilane, N, N-bis (trimethylsilyl) aminopropyl (ethyl) dipropoxysilane, N, N-bis (trimethylsilyl) aminoethyl (methyl) ) Dimethoxysilane, N, N-bis (trimethylsilane) L) aminoethyl (methyl) diethoxysilane, N, N-bis (trimethylsilyl) aminoethyl (methyl) dipropoxysilane, N, N-bis (trimethylsilyl) aminoethyl (ethyl) dimethoxysilane, N, N-bis ( And trimethylsilyl) aminoethyl (ethyl) diethoxysilane, N, N-bis (trimethylsilyl) aminoethyl (ethyl) dipropoxysilane, and the like. Among these, N, N-bis (trimethylsilyl) aminopropyl (methyl) dimethoxysilane, N, N-bis (trimethylsilyl) aminopropyl (methyl) diethoxysilane and N, N-bis (trimethylsilyl) aminopropyl (methyl) ) Dipropoxysilane is preferred.

  Moreover, as a compound represented by the said General formula (1), when X has a secondary amino group protected by the detachable group, for example, N-methyl-N-trimethylsilylaminopropyl (methyl) ) Dimethoxysilane, N-methyl-N-trimethylsilylaminopropyl (methyl) diethoxysilane, N-trimethylsilyl (hexamethyleneimin-2-yl) propyl (methyl) dimethoxysilane, N-trimethylsilyl (hexamethyleneimin-2-yl) ) Propyl (methyl) diethoxysilane, N-trimethylsilyl (pyrrolidin-2-yl) propyl (methyl) dimethoxysilane, N-trimethylsilyl (pyrrolidin-2-yl) propyl (methyl) diethoxysilane, N-trimethylsilyl (piperidine-) 2-yl) propyl (meth) ) Dimethoxysilane, N-trimethylsilyl (piperidin-2-yl) propyl (methyl) diethoxysilane, N-trimethylsilyl (imidazol-2-yl) propyl (methyl) dimethoxysilane, N-trimethylsilyl (imidazol-2-yl) propyl (Methyl) diethoxysilane, N-trimethylsilyl (4,5-dihydroimidazol-5-yl) propyl (methyl) dimethoxysilane, N-trimethylsilyl (4,5-dihydroimidazol-5-yl) propyl (methyl) diethoxy A silane etc. can be mentioned.

(2) Silane compound II
On the other hand, examples of the modifier represented by the silane compound II include silane compounds selected from the following general formula (2), general formula (3), and general formula (4).

Wherein R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{5 to} R ⁷ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁸ 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 ^{9 to} R ¹³ each independently represent a hydrocarbon group having 1 to 20 carbon atoms, R ¹⁴ represents a divalent hydrocarbon group having 1 to 12 carbon atoms, and n represents 1 or 2.)

（式中、Ｒ³、Ｒ⁴は、それぞれ独立に炭素数１〜２０の炭化水素基、Ｒ⁵〜Ｒ⁷は、それぞれ独立に炭素数１〜２０の炭化水素基、Ｒ⁸は炭素数１〜１２の２価の炭化水素基、Ｒ¹⁵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 ³ and R ⁴ are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{5 to} R ⁷ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁸ is a carbon number 1 -12 divalent hydrocarbon group, R ¹⁵ is a C 1-12 divalent hydrocarbon group, A is a reactive group, and f is an integer of 1-10.

In the above formulas (2) to (4), 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 or a hydrocarbyloxy group having 1 to 20 carbon atoms. 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, an aralkyloxy group having 7 to 20 carbon atoms, and the like.
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 a decyloxy group, 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 methoxy group and ethoxy group are particularly preferable.
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 ⁵ , R ⁶ and R ^{7 in} the formula (2) may be bonded to form a 4- to 7-membered ring together with the silicon atom to which they are bonded. Two of R ¹¹ , R ¹² and R ¹³ in (3) 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.
In the formula (3), n is 1 or 2.

In the general formula (2), when f is 1 and A is an alkoxy group, as the silane compound represented by the general formula (2), in the compound represented by the general formula (1), X is The same thing as the silane compound shown as a specific example in case it has the primary amino group protected by the detachable group can be mentioned.
Examples of the silane compound in which f is 1 and A is a halogen atom include N, N-bis (trimethylsilyl) aminopropyl (methyl) methoxychlorosilane, N, N-bis (trimethylsilyl) aminopropyl (methyl) ethoxychlorosilane, N , N-bis (trimethylsilyl) aminoethyl (methyl) methoxychlorosilane, N, N-bis (trimethylsilyl) aminoethyl (methyl) ethoxychlorosilane, and the like.

Examples of the silane compound represented by the general formula (3) include 1-trimethylsilyl-2-ethoxy-2-methyl-1-aza-2-silacyclopentane, 1-trimethylsilyl-2-methoxy-2-methyl- 1-aza-2-silacyclopentane, 1-trimethylsilyl-2,2-diethoxy-1-aza-2-silacyclopentane, 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane, etc. Is mentioned.
In the general formula (4), when f is 1 and A is an alkoxy group, examples of the silane compound represented by the general formula (4) include (2,2,5,5-tetramethyl- 1-aza-2,5-disilacyclopentan-1-yl) propyl (methyl) dimethoxysilane, (2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentane-1 -Yl) propyl (methyl) diethoxysilane and the like.
In the present invention, among the modifiers, in particular, N, N-bis (trimethylsilyl) aminopropyl (methyl) dimethoxysilane, N, N-bis (trimethylsilyl) aminopropyl (methyl) diethoxysilane, 1-trimethylsilyl 2-Ethoxy-2-methyl-1-aza-2-silacyclopentane is preferred.
These modifiers may be used alone or in combination of two or more.

《Modification reaction》
In the modification reaction in the present invention, modification is performed by reacting at least one selected from the aforementioned modifiers with the active terminal of polybutadiene having an organic alkali metal active terminal.
The modification reaction with the modifying agent is preferably performed by a solution reaction, and the solution may contain a monomer used during polymerization. The reaction mode of the modification reaction is not particularly limited, and may be a batch type or a continuous type.
In this modification reaction, it is preferable that the polybutadiene to be used has at least 10% of polymer chains having a living property.

In the modification reaction with the above modifier, the amount of the modifier used is preferably 0.5 to 200 mmol / kg · polybutadiene. The content is more preferably 1 to 100 mmol / kg · polybutadiene, and particularly preferably 2 to 50 mmol / kg · polybutadiene. Here, polybutadiene 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, the amine functional group modified polybutadiene rubber which has a desired property is obtained.
In addition, the addition method of the modifier is not particularly limited, and examples thereof include a batch addition method, a division addition method, a continuous addition method, and the like. preferable.

<Condensation reaction>
In the present invention, in order to accelerate the condensation reaction involving the hydrocarbyloxysilane compound used as the aforementioned modifier, after the modification reaction, the condensation reaction may be performed in the presence of a condensation accelerator as necessary. Good.
As the condensation accelerator, a compound of an element belonging to at least one of Group 4, Group 13, Group 14 and Group 15 of the periodic table (long period type) is used.
As the condensation accelerator, at least one selected from a titanium compound, a tin compound, a zirconium compound, a bismuth compound, and an aluminum compound is preferably used, and more preferably, the alkoxide or carboxyl of each of the above elements. Acid salt and acetylacetonate complex salt, more preferably titanium alkoxide, titanium carboxylate, tin carboxylate, bismuth carboxylate, zirconium alkoxide, zirconium carboxylate, aluminum alkoxide and It is an aluminum carboxylate.

  Specific examples of the titanium compound 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-) , 3-Heptanediolato) 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 -Butoxytitanium, tetra-tert-butoxytitanium, bis (oleate) bis (2-ethylhexanoate) titanium, titanium dipropoxybis (triethanolamate), titanium dibutoxybis (triethanolamate) , Titanium tributoxy systemate, titanium tripropoxy systemate, titanium tripropoxyacetylacetonate, titanium dipropoxybis (acetylacetonate), titanium tripropoxy (ethylacetoacetate), titaniumpropoxyacetylacetonatebis (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 (naphth Tenate) titanium oxide, bis (stearate) titanium oxide, bis (oleate) titanium oxide, bis (linoleate) titanium oxide, tetrakis (2-ethylhexanoate) titanium, tetrakis (laurate) titanium, tetrakis (naphthenate) titanium, Tetrakis (stearate) titanium, Tetrakis (oleate) titanium, Tetrakis (linoleate) titanium, Titanium di-n-butoxide (bis-2,4-pentandionate), Titanium oxide bis (stearate), Titanium oxide bis (tetramethyl) Heptanedionate), 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.

Specific examples of the tin compound include tin 2-ethylhexanoate {[CH ₃ (CH ₂ ) ₃ CH (C ₂ H ₅ ) CO ₂ ] ₂ Sn (divalent)}.
Specific examples of the bismuth compound include tris (2-ethylhexanoate) bismuth, tris (laurate) bismuth, tris (naphthenate) bismuth, tris (stearate) bismuth, tris (oleate) bismuth, and tris (linoleate). ) Bismuth and the like can be mentioned.

    Specific examples of the zirconium compound include tetraethoxyzirconium, tetran-propoxyzirconium, tetraisopropoxyzirconium, tetran-butoxyzirconium, tetrasec-butoxyzirconium, tetratert-butoxyzirconium, tetra (2-ethyl heptane). Xylyl) zirconium, zirconium tributoxy systemate, zirconium tributoxyacetylacetonate, zirconium dibutoxybis (acetelacetonate), zirconium tributoxyethylacetoacetate, zirconiumbutoxyacetylacetonatebis (ethylacetoacetate), zirconium tetrakis ( Acetylacetonate), zirconium diacetylacetonate bis (ethylacetoacetate), bis (2- Ethylhexanoate) zirconium oxide, bis (laurate) zirconium oxide, bis (naphthenate) zirconium oxide, bis (stearate) zirconium oxide, bis (oleate) zirconium oxide, bis (linoleate) zirconium oxide, tetrakis (2-ethylhexa) Noate) zirconium, tetrakis (laurate) zirconium, tetrakis (naphtheneate) zirconium, tetrakis (stearate) zirconium, tetrakis (oleate) zirconium, tetrakis (linoleate) zirconium and the like.

  Specific examples of the aluminum compound include triethoxyaluminum, tri-n-propoxyaluminum, tri-i-propoxyaluminum, tri-n-ptoxyaluminum, trisec-butoxyaluminum, tritert-butoxyaluminum, tri (2- Ethylhexyl) aluminum, aluminum dibutoxy systemate, aluminum dibutoxyacetylacetonate, aluminum butoxybis (acetylacetonate), aluminum dibutoxyethylacetoacetate, aluminum tris (acetelacetonate), aluminum tris (ethylacetoacetate) ), Tris (2-ethylhexanoate) aluminum, tris (laurate) aluminum, tris (naphthenate) aluminum, tris ( Teareto) aluminum, tris (oleate) aluminum, can be mentioned tris (linolate) aluminum and the like.

The amount of the condensation accelerator used is preferably such that the number of moles of the above compound is 0.1 to 10 as the molar ratio to the total amount of hydrocarbyloxy groups bonded to silicon atoms present in the reaction system. 5 to 5 is particularly preferable. By setting the use amount of the condensation accelerator within the above range, the condensation reaction proceeds efficiently.
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.

The condensation reaction in the present invention is preferably carried out in the presence of water, and the temperature during the condensation reaction is preferably 10 to 180 ° C, more preferably 20 to 170 ° C, and particularly preferably 30 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 deterioration in quality due to the aging reaction of the polymer due to aging of the resulting modified polybutadiene rubber 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.
The pressure of the reaction system during the condensation reaction is usually 0.01 to 20 MPa, preferably 0.05 to 10 MPa.
There is no restriction | limiting in particular about the form of a condensation reaction, 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.
When a hydrocarbyloxysilane compound having a protected primary amino group and / or secondary amino group was used as a modifier, the removable group in the protected amino group was liberated by hydrolysis. Can be converted to an amino group. By removing this solvent, a dried polymer having a primary amino group or a secondary amino group can be obtained. In addition, the deprotection treatment of the protected primary amino group and / or the secondary amino group derived from the modifier is performed as necessary in any stage from the stage including the condensation treatment to the solvent removal to the dry polymer. Can do.

The amine functional group-modified polybutadiene rubber thus obtained is formed by bonding a silicon atom having a nitrogen-containing functional group to a polymer terminal, and the nitrogen-containing functional group is a primary amino group, a second amino group, Examples thereof include an amino group and a salt thereof, and a structure having at least one selected from a primary amino group and a secondary amino group protected with a detachable group.
Moreover, the thing of the structure where a hydrocarbyloxy group and / or a hydroxy group couple | bond with the silicon atom which has the said nitrogen-containing functional group can also be mentioned.
In the amine-based functional group-modified polybutadiene rubber having such a structure, the nitrogen-containing functional group has a good interaction with carbon black and silica, while the hydrocarbyloxysilane group and silanol group are In particular, it has an excellent interaction with silica. Therefore, by using the rubber composition containing the modified polybutadiene rubber for the belt undercushion rubber, the increase in tire temperature during running is suppressed without impairing the crack resistance of the rubber, and the ply adhesion durability is greatly increased. An improved heavy duty pneumatic tire can be provided.

In the amine-based functional group-modified polybutadiene rubber, the weight average molecular weight Mw in terms of polystyrene of the polybutadiene rubber before modification measured by gel permeation chromatography method (GPC method) is usually about 100,000 to 700,000. The weight average molecular weight Mw / number average molecular weight Mn ratio, which is a molecular weight distribution, is usually 3 or less, preferably 2 or less before modification.
Furthermore, it is preferable that the glass transition temperature (Tg) calculated | required by the differential thermal analysis method of the said modified polybutadiene rubber is -110 degreeC--50 degreeC. By setting the glass transition temperature within this range, it is possible to obtain a polybutadiene that suppresses an increase in viscosity and is easy to handle.
The Mooney viscosity (ML _{1 + 4} , 100 ° C.) of the modified polybutadiene rubber 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 provided.

<(A) Composition of rubber component>
In the rubber composition according to the present invention, the rubber component used as the component (A) includes (a) 10 to 100% by mass of the amine functional group-modified polybutadiene rubber, and (b) natural rubber and / or synthetic conjugate. Those containing 90 to 0% by mass of diene rubber are preferred. If content of the said (a) component is 10 mass% or more, the effect of this invention will be exhibited favorable. (A) More preferable content of a component is 50-100 mass%.
Examples of the synthetic conjugated diene rubber in the component (b) include synthetic isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-α-olefin copolymer rubber, ethylene-α-olefin-diene copolymer rubber, and acrylonitrile. -Butadiene copolymer rubber, chlorobrene rubber, halogenated butyl 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.
In the present invention, natural rubber is particularly suitable as the component (b) from the viewpoint of the performance of the rubber composition.

((B) Reinforcing filler)
In the rubber composition according to the present invention, carbon black and / or silica is preferably used as the reinforcing filler of the component (B).
There is no restriction | limiting in particular as said carbon black, From what is conventionally used as a reinforcing filler of rubber | gum, arbitrary things can be selected suitably and can be used. For example, SRF, GPF, FEF, HAF, ISAF, SAF and the like are used, and HAF, ISAF, and SAF that are particularly excellent in wear resistance are preferable.
This carbon black may be used alone or in combination of two or more.
On the other hand, examples of silica include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and the like. Among these, wet silica is preferable.
The wet silica preferably has a BET specific surface area of 40 to 350 m ² / g. Silica having a BET specific surface area within this range has an advantage that both rubber reinforcement and dispersibility in a rubber component can be achieved. From this viewpoint, silica having a BET specific surface area in the range of 80 to 300 m ² / g is more preferable. As such silica, commercially available products such as “Nipsil AQ”, “Nipsil KQ” manufactured by Tosoh Silica Co., Ltd., “Ultrasil VN3” manufactured by Degussa Co., Ltd. can be used.
This silica may be used alone or in combination of two or more.

  In the rubber composition according to the present invention, the content of the reinforcing filler, preferably the carbon black and / or silica, is 30 to 65 parts by mass with respect to 100 parts by mass of the (A) rubber component. Is preferable, and it is more preferable that it is 35-60 mass parts. If this content is 30 parts by mass or more, the fracture resistance of the belt undercushion rubber is good, and it is difficult to cause in-rubber breakage. Can be suppressed.

(Silane coupling agent)
In the rubber composition according to the present invention, when silica is used as the reinforcing filler, a silane coupling agent can be blended for the purpose of further improving the reinforcing property and low exothermic property.
Examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, and bis (2-triethoxy). Silylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyl Trimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarbamo Yl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilylpropylbenzoyl tetrasulfide, 3-triethoxysilyl Propyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide , Dimethoxymethylsilylpropylbenzothiazolyl tetrasulfide, and the like. Among these, bis (3-triethoxy Rirupuropiru) polysulfide and 3-trimethoxysilylpropyl benzothiazyl tetrasulfide are preferable.
One of these silane coupling agents may be used alone, or two or more thereof may be used in combination.

  In the rubber composition according to the present invention, the preferable blending amount of the silane coupling agent varies depending on the type of the silane coupling agent and the like, 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.

(Preparation of rubber composition)
In the rubber composition according to the present invention, various chemicals usually used in the rubber industry, for example, a vulcanizing agent, a vulcanization accelerator, a process oil, and an anti-aging agent, as long as the object of the present invention is not impaired. , 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 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 used, and the amount used is 0.1-5. 0 mass part is preferable, More preferably, it is 0.2-3.0 mass part.

  Examples of the process oil that can be used in the rubber composition according to 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, and if it exceeds 100 parts by mass, the tensile strength and low heat build-up of the vulcanized rubber tend to deteriorate.

[Pneumatic tire for heavy loads]
The heavy duty pneumatic tire of the present invention is characterized in that the rubber composition according to the present invention described above is used for a belt undercushion rubber.
First, (A) a rubber component containing 10% by mass or more of an amine-based functional group-modified polybutadiene rubber, (B) a reinforcing filler, and various chemicals used as necessary are respectively used at a predetermined ratio, and a roll A rubber composition is prepared by kneading using a kneader such as an internal mixer. Next, this rubber composition is processed into a belt undercushion rubber at an unvulcanized stage, and is pasted and molded by a usual method on a tire molding machine to form a raw tire. The green tire for heavy loads according to the present invention is obtained by heating and pressing the green tire in a vulcanizer.

  A heavy duty pneumatic tire generally includes a tread and a tread belt interposed between the tread and the carcass. A belt undercushion formed of an elastomer material having a relatively low M200% modulus on the inner side of the belt (between the belt and the carcass, and in some cases including a shoulder integrally from the belt end portion to the central portion) To an elastomer material). This cushion functions as a shock absorber between the relative lateral edges of the tread belt and the body ply, and is inserted to increase the wear resistance of the tread and the life of the carcass. The cushion has a function of distributing the internal stress of the carcass over the entire tread surface.

In tires, particularly heavy-duty pneumatic tires, belt undercushion rubber is required to reduce the distortion and end of the belt end, which is likely to cause failure, and to obtain high tire durability.
The present invention uses the above-described rubber composition according to the present invention for the belt undercushion rubber, thereby suppressing an increase in tire temperature during running without impairing the crack resistance of the rubber, and maintaining a ply adhesion durability. A tire with greatly improved properties, particularly a heavy duty pneumatic tire is provided.

The heavy-duty pneumatic tires of the present invention can be broadly classified into off-the-road tires for large construction vehicles and truck and bus tires. Each tire will be described with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of an example of a radial tire for off-the-road. In the radial tire 1 for off-the-road, the belt undercushion rubber 3 is the widest belt layer in the belt main layer 4. The belt main trunk layer 4 is arranged on the inner side in the tire radial direction from the free end to the carcass 2. The belt undercushion rubber 3 may extend to the end of the carcass ply if desired. In the figure, reference numeral 5 denotes a belt protective layer.
On the other hand, FIG. 2 is a cross-sectional view of an example of a truck / bus radial tire. In the truck / bus radial tire 11, the belt undercushion rubber 13 is the free belt layer of the belt main layer 14. The belt main trunk layer 14 is disposed on the inner side in the tire radial direction from the end to the carcass 12. In the figure, reference numeral 15 denotes a belt protective layer as in FIG.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, about the performance of the tire obtained in each case, it evaluated in accordance with the method shown below.
(1) Evaluation of tire temperature during running Under a load 1.3 times the normal load, running on the drum at a normal internal pressure of 10 km / h, the surface temperature of the tire shoulder after 1 hour Measured with a contact thermometer. At that time, each of the left and right sides was measured and the average value was used to describe the temperature difference from Comparative Example 1.
(2) Evaluation of ply adhesion resistance After running further for 480 hours under the same conditions as described above, evaluation with rubber was performed as the remaining adhesion of the ply cord. When the ply cord is completely covered with rubber, rubber is attached = 100% (residual adhesion is good), and when the rubber is not covered at all, rubber is attached = 0 (residual adhesion is low).
(3) Evaluation of crack resistance of belt undercushion rubber After buffing the tread part of the tire until the remaining groove becomes 10 mm, at a speed of 10 km / h with a normal load and a normal internal pressure with a drum with a slip angle. It was run for 800 hours. The belt undercushion part after running was observed and the presence or absence of rubber destruction was observed.

Production Example 1 Production of Modification Agent After adding 36 g of 3-aminopropyl (methyl) diethoxysilane (manufactured by Gelest) as an aminosilane site in 400 ml of dichloromethane solvent in a glass flask equipped with a stirrer under a nitrogen atmosphere, 48 ml of trimethylsilane chloride (manufactured by Aldrich) and 53 ml of triethylamine are added to the solution as protective sites, and the mixture is stirred for 17 hours at room temperature. Thereafter, the solvent is 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) aminopropyl (methyl) diethoxysilane as a modifier that was a fraction at 130 to 135 ° C.

Production Example 2 Production of Unmodified Polybutadiene Rubber In a pressure-resistant glass container having an inner volume of about 900 ml that was dried and purged with nitrogen, 283 g of cyclohexane, 100 g of 1,3-butadiene monomer, and 0.015 mmol of 2,2-ditetrahydrofurylpropane were added. The solution was injected as a cyclohexane solution, 0.50 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion rate was almost 100%. Thereafter, 0.5 ml of 2,6-di-tert-butyl-p-cresol (BHT) isopropanol 5% by mass solution was added to stop the reaction, followed by drying according to a conventional method. Got rubber. The obtained unmodified polybutadiene rubber had a weight average molecular weight of 300,000, and a vinyl bond content by infrared method (Morello method) was 20%.

Production Example 3 Production of Modified Polybutadiene Rubber In a pressure-resistant glass container having an inner volume of about 900 ml that was dried and purged with nitrogen, 283 g of cyclohexane, 100 g of 1,3-butadiene monomer, and 0.015 mmol of 2,2-ditetrahydrofurylpropane were added to cyclohexane. The solution was injected as a solution, 0.50 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion rate was almost 100%. To this polymerization system, 0.50 mmol of N, N-bis (trimethylsilyl) aminopropyl (methyl) diethoxysilane was added as a cyclohexane solution and stirred at 50 ° C. for 30 minutes. Thereafter, the reaction was stopped by adding 0.5 ml of a 5 mass% solution of 2,6-di-tert-butyl-p-cresol (BHT) in isopropanol, and further dried according to a conventional method, thereby modifying the modified polybutadiene rubber. Got. The resulting modified polybutadiene rubber had a vinyl bond content of 20% by infrared method (Morero method).

Examples 1-4 and Comparative Examples 1-7
A rubber composition having the compounding composition shown in Table 1 was prepared, and each of the rubber compositions was applied to a belt undercushion rubber to produce an off-the-road tire of size 40.00R57. Performance was evaluated. The results are shown in Table 1.

［注］
１）未変性ＢＲ：製造例２で得られた未変性ポリブタジエンゴム
２）変性ＢＲ：製造例３で得られた変性ポリブタジエンゴム
３）カーボンブラックＮ３３０：旭カーボン社製「＃７０」
４）老化防止剤：老化防止剤６ＰＰＤ、大内新興化学工業社製「ノクラック６Ｃ」
５）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 BR: Unmodified polybutadiene rubber obtained in Production Example 2 2) Modified BR: Modified polybutadiene rubber obtained in Production Example 3 3) Carbon black N330: “# 70” manufactured by Asahi Carbon Co., Ltd.
4) Anti-aging agent: Anti-aging agent 6PPD, “NOCRACK 6C” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
5) Vulcanization accelerator CZ: “Noxeller CZ” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

  As can be seen from Table 1, the off-the-road tire using the rubber composition according to the present invention (Examples 1 to 4) as the belt undercushion rubber is running more than the comparative example. The tire temperature is generally low, the ply adhesion resistance is as good as 65% or more, and no crack of the belt undercushion rubber is observed.

  By using the rubber composition according to the present invention for a tire, particularly a belt undercushion rubber for a heavy-duty pneumatic tire, it is possible to suppress an increase in tire temperature during running without impairing the crack resistance of the rubber and to adhere a ply. A tire having greatly improved durability, particularly a heavy duty pneumatic tire, can be provided.

It is sectional drawing of an example of the radial tire for off-the-road. It is sectional drawing of an example of the radial tire for trucks and buses.

Explanation of symbols

1 Radial tire for off-the-road 11 Radial tire for truck and bus 2, 12 Carcass 3, 13 Belt under cushion rubber 4, 14 Belt trunk layer 5, 15 Belt protective layer

Claims (24)

  A rubber composition containing (A) a rubber component containing an amine-based functional group-modified polybutadiene rubber having an amino group protected with a protic amino group and / or a detachable group, and (B) a reinforcing filler. A tire characterized by being used for belt undercushion rubber.   The tire according to claim 1, wherein the amine-based functional group-modified polybutadiene rubber further has a silicon atom.   The tire according to claim 2, wherein the silicon atom is a silicon atom bonded to a hydrocarbyloxy group and / or a hydroxy group.   The amine-based functional group-modified polybutadiene rubber has an amino group protected by the protonic amino group and / or a detachable group at the polymerization end, and a silicon atom bonded to the hydrocarbyloxy group and / or hydroxy group. The tire according to claim 3.   The amino group protected by the protic amino group and / or the detachable group and the silicon atom to which the hydrocarbyloxy group and / or hydroxy group are bonded at the same polymerization active terminal. tire.   The tire according to any one of claims 1 to 5, wherein the protic amino group is at least one selected from a primary amino group, a secondary amino group, and a salt thereof.   The tire according to any one of claims 1 to 5, wherein the amino group protected by the detachable group is an N, N-bis (trimethylsilyl) amino group and / or an N- (trimethylsilyl) imino group.   The amine-based functional group-modified polybutadiene rubber has a primary amino group and / or a secondary amino group-containing group and a hydrocarbyloxy group protected by a detachable group as a modifier at the active end of the polybutadiene having an active end. The tire according to any one of claims 1 to 7, which is obtained by reacting and modifying a silane compound formed by bonding to the same silicon atom. The modifier is represented by the general formula (1)

[Wherein Y is a hydrocarbyloxy group, R ¹ is a monovalent hydrocarbon group, R ² is a divalent hydrocarbon group, X is a primary amino group and / or a secondary amino group protected with a detachable group. Represents a group, and m represents an integer of 1 to 3. However, active protons and onium salts are not included in the molecule. ]
The tire according to claim 8, wherein the tire is a silane compound and / or a partial condensate thereof. In general formula (1), Y is a hydrocarbyloxy group having 1 to 18 carbon atoms, R ¹ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, and R ² is a divalent hydrocarbon group having 1 to 20 carbon atoms. The tire according to claim 9.   The tire according to claim 9 or 10, wherein in X in the general formula (1), the detachable group protecting the primary amino group or the secondary amino group is a trimethylsilyl group. The modifier is represented by the general formula (2)

Wherein R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{5 to} R ⁷ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁸ is a carbon number 1 A silane compound represented by formula (3): a divalent hydrocarbon group of -12, A is a reactive group, and f is an integer of 1-10.

(Wherein R ^{9 to} R ¹³ are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ¹⁴ is a divalent hydrocarbon group having 1 to 12 carbon atoms, and n is 1 or 2). Silane compounds represented by the general formula (4)

Wherein R ³ and R ⁴ are each independently a hydrocarbon group having 1 to 20 carbon atoms, R ^{5 to} R ⁷ are each independently a hydrocarbon group having 1 to 20 carbon atoms, and R ⁸ is a carbon number 1 -12 divalent hydrocarbon group, R ¹⁵ 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 tire according to claim 8 selected from the inside.   The tire according to claim 12, wherein A in the general formula (2) and the general formula (4) is a halogen atom or a hydrocarbyloxy group having 1 to 20 carbon atoms.   The tire according to any one of claims 8 to 13, wherein the modifier is N, N-bis (trimethylsilyl) aminopropyl (methyl) dimethoxysilane or N, N-bis (trimethylsilyl) aminopropyl (methyl) diethoxysilane. .   The modifier is 1-trimethylsilyl-2-ethoxy-2-methyl-1-aza-2-silacyclopentane, 1-trimethylsilyl-2-methoxy-2-methyl-1-aza-2-silacyclopentane, The tire according to claim 12, which is trimethylsilyl-2,2-diethoxy-1-aza-2-silacyclopentane or 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane.   The tire according to any one of claims 8 to 15, wherein the polybutadiene having an active end is obtained by anionic polymerization of 1,3-butadiene using an organic alkali metal compound as a polymerization initiator.   The amine functional group-modified polybutadiene rubber has, as a modifier, a primary amino group and / or a secondary amino-containing group protected with a detachable group and a hydrocarbyloxy group at the active end of the polybutadiene having an active end. After reacting and modifying a silane compound bonded to the same silicon atom, a compound of an element belonging to any of Groups 4, 13, 14, and 15 of the periodic table (long-period type) The tire according to any one of claims 8 to 16, wherein the tire is obtained by performing a condensation reaction involving the silane compound in the presence of a condensation accelerator comprising:   The tire according to claim 17, wherein the condensation accelerator is an alkoxide, carboxylate, or acetylacetonate complex of titanium, zirconium, bismuth or aluminum.   The rubber component (A) contains (a) 10 to 100% by mass of an amine functional group-modified polybutadiene rubber and (b) 90 to 0% by mass of a natural rubber and / or a synthetic conjugated diene rubber. The tire according to any one of the above.   The tire according to claim 19, wherein the component (b) is natural rubber.   The reinforcing filler of component (B) is carbon black and / or silica, and its content is 30 to 65 parts by mass with respect to 100 parts by mass of (A) rubber component. The tire according to any one of the above.   The tire according to claim 21, comprising a silane coupling agent in a proportion of 2 to 20 mass% with respect to the silica.   The tire according to any one of claims 1 to 22, which is a heavy duty pneumatic tire.   The tire according to claim 23, which is for off-the-road use or truck / bus use.

Images