JP2011084222A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire improved in rolling resistance and riding comfort during normal traveling by improving the run-flat durability. <P>SOLUTION: This pneumatic tire includes bead cores, a carcass layer formed of one or more carcass plies formed by coating a reinforcement cord with a ply coating rubber, a tread rubber layer, an inner liner, a side rubber layer, a side reinforcement rubber layer, and bead fillers. The side reinforcement rubber and/or the bead filler uses a rubber composition (a) which includes (A) a rubber component and (B) a filler and has a dynamic strain of 1% and a dynamic storage modulus (E') at 25°C of 10 MPa or less in physical properties of vulcanized rubber. The ply coating rubber uses a rubber composition (b) which has a dynamic strain of 1% and a tangent loss (tan δ) at 25°C of 0.12 or less. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the vulcanized rubber characteristics, the present invention uses a rubber composition having a dynamic storage elastic modulus (E ′) of a certain value or less for a side reinforcing rubber layer and / or a bead filler, and has a loss tangent (tan δ) of a value or less. The present invention relates to a pneumatic tire that is excellent in run-flat durability using the above rubber composition as a carcass ply coating rubber and has improved rolling resistance and riding comfort during normal running.

2. Description of the Related Art Conventionally, in a pneumatic tire, particularly a run-flat tire, a side reinforcing rubber layer made of a rubber composition alone or a composite of a rubber composition and fibers has been provided to improve the rigidity of a sidewall portion. (For example, see Patent Document 1)
Pneumatic tires run when the internal pressure of the tire (hereinafter referred to as internal pressure) drops due to puncture, etc., so-called run-flat running state, the deformation of the tire sidewall and bead filler increases, and heat is generated. In some cases, the temperature reaches 200 ° C. or higher.
In such a state, even in a pneumatic tire provided with a side reinforcing rubber layer, the side reinforcing rubber layer and the bead filler exceed the breakage limit, resulting in a tire failure.
As a means of prolonging the time until failure such as this, the side wall of the tire is obtained by highly blending the rubber composition used for the side reinforcing rubber layer and the bead filler and making the rubber composition highly elastic. Although there is a technique for suppressing the deformation amount of the part and the bead filler, there is a problem that the rolling resistance during normal running of the tire increases and the fuel efficiency decreases.

On the other hand, Patent Document 2 proposes to use a rubber composition containing various modified conjugated diene-aromatic vinyl copolymers and a heat resistance improver for the side reinforcing rubber layer and the bead filler.
Further, Patent Document 3 proposes that a rubber composition containing a specific conjugated diene polymer and a phenol resin is used for the side reinforcing rubber layer and the bead filler.
These are all intended to increase the elastic modulus of the rubber composition used for the side reinforcing rubber layer and the bead filler, and to suppress a decrease in the elastic modulus at high temperatures. Although improvement can be obtained, the rolling resistance during normal running is significantly deteriorated.

On the other hand, as means for increasing the time to failure, there are those that increase the volume of rubber, such as increasing the maximum thickness of the disposed side reinforcing rubber layer and the bead filler. Undesirable situations such as deterioration in riding comfort during normal driving, an increase in weight, and an increase in noise level occur.
If the volume of the side reinforcing rubber layer and the bead filler to be disposed is reduced in order to avoid the above-mentioned situation, for example, deterioration of the ride comfort, the load at the time of run flat cannot be supported, and the side wall portion of the tire at the time of run flat The deformation of the rubber composition becomes very large, which causes an increase in heat generation of the rubber composition, and as a result, there is a problem that the tire fails earlier.
Similarly, when the rubber used is made to be less elastic by changing the compounding material, the rubber composition is not able to support the load during run-flat, and the deformation of the sidewall portion of the tire becomes very large. As a result, the tires are likely to break down earlier as a result.

  Also, the side rubber and the ply coating rubber generate heat due to large shear strain and bending strain, respectively, during run flat running, and promote heat generation of the side reinforcing rubber to reduce run flat durability. Although the low heat generation of the side reinforcing rubber is very effective for improving the run-flat durability, further improvements including the side rubber as a peripheral member and particularly the ply coating rubber are desired.

JP 2002-103925 A WO02 / 02356 brochure JP 2004-74960 A

  Under such circumstances, an object of the present invention is to provide a pneumatic tire with improved run flat durability and improved rolling resistance and riding comfort during normal driving.

As a result of intensive studies to develop a pneumatic tire having the above-mentioned preferable properties, the present inventor has obtained a rubber composition having a dynamic storage elastic modulus (E ′) which is not more than a certain value in physical properties of vulcanized rubber. It was found that a pneumatic tire using a rubber composition used for a side reinforcing rubber layer and / or a bead filler and having a loss tangent (tan δ) equal to or less than a value for a carcass ply coating rubber can meet the purpose. . The present invention has been completed based on such findings.
That is, the present invention
[1] A pneumatic tire comprising a bead core, a carcass layer made of at least one carcass ply formed by covering a reinforcing cord with a ply coating rubber, a tread rubber layer, an inner liner, a side rubber layer, a side reinforcing rubber layer, and a bead filler. The side reinforcing rubber and / or the bead filler contains (A) a rubber component and (B) a filler, and in the physical properties of vulcanized rubber, the dynamic storage elastic modulus (E) at 25 ° C. is 1% in dynamic strain. A rubber composition (a) having a rubber composition (a) of 10 MPa or less and a vulcanized rubber property of the ply-coated rubber having a dynamic strain of 1% and a loss tangent (tan δ) at 25 ° C of 0.12 or less ( a pneumatic tire characterized by using b),
[2] The air of [1] above, wherein in the rubber composition (a), the loss tangent (tan δ) at 28% to 150 ° C. at a dynamic strain of 1%, which is a vulcanized rubber property, is 5.0 or less. Entered tires,
[3] In the rubber composition (a), the air of [1] or [2] above, wherein the blending amount of the filler of the component (B) is 50 parts by mass or less with respect to 100 parts by mass of the rubber component (A) Entered tires,
[4] The filler of component (B) is carbon black, silica, and general formula (I)
nM · xSiO _y · zH ₂ O (I)
[In the formula, M is at least selected from metals selected from aluminum, magnesium, titanium, calcium and zirconium, oxides or hydroxides of these metals, hydrates thereof, and carbonates of the metals. N, x, y, and z are each an integer of 1 to 5, an integer of 0 to 10, an integer of 2 to 5, and an integer of 0 to 10. ]
The pneumatic tire according to any one of the above [1] to [3], which is at least one selected from inorganic fillers represented by:
[5] The pneumatic tire of the above [4], wherein the filler of the component (B) is carbon black,
[6] The pneumatic tire according to [5], wherein the carbon black is at least one selected from FEF grade, FF grade, HAF grade, ISAF grade and SAF grade,
[7] The pneumatic tire of [6] above, wherein the carbon black is FEF grade grade,
[8] The pneumatic tire according to any one of the above [1] to [7], wherein in the rubber composition (a), (A) the rubber component contains a modified conjugated diene polymer.
[9] The pneumatic tire according to [8], wherein the modified conjugated diene polymer is an amine-modified conjugated diene polymer.
[10] The pneumatic tire according to [9], wherein the amine-modified conjugated diene polymer is a protic amine-modified conjugated diene polymer,
[11] The pneumatic tire according to [9] or [10], wherein the amine-modified conjugated diene polymer is a primary amine-modified conjugated diene polymer.
[12] The pneumatic tire according to the above [11], wherein the primary amine-modified conjugated diene polymer is obtained by reacting a protected primary amine compound with an active terminal of the conjugated diene polymer.
[13] The above conjugated diene polymer is obtained by anionic polymerization of a conjugated diene compound alone or a conjugated diene compound and an aromatic vinyl compound in an organic solvent using an organic alkali metal compound as an initiator. [12] a pneumatic tire,
[14] The pneumatic tire of [13] above, wherein the conjugated diene polymer is polybutadiene.
[15] The pneumatic tire according to any one of the above [12] to [14], wherein the protected primary amine compound is N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane.
[16] The pneumatic tire according to the above [1], wherein in the vulcanized rubber properties of the rubber composition (b), the dynamic elastic modulus (E ′) at a dynamic strain of 1% at 25 ° C. is 6.0 MPa or more, and [17] The pneumatic tire according to the above [1] or [16], wherein the rubber composition (b) applied to the coating rubber is a rubber component blended with carbon black of FEF class or lower.
Is to provide.

According to the invention described in [1] above, a rubber composition having a vulcanized rubber property of a side reinforcing rubber and / or a bead filler and a dynamic storage elastic modulus (E ′) at 25 ° C. of 10% or less at a dynamic strain of 1%. By using the rubber composition (b) having a vulcanized physical property of 1% and a loss tangent (tan δ) at 25 ° C. of 0.12 or less in a vulcanized physical property of the ply coating rubber, Alternatively, the bead filler rubber is softened to improve the riding comfort during normal running, and the run-flat durability is further improved by using the low heat-generating rubber composition (b) as the ply coating rubber.
According to the invention described in [2] above, the Σ value at 28 ° C. to 150 ° C. of the loss tangent (tan δ) at a dynamic strain of 1%, which is the physical property of the vulcanized rubber of the rubber composition (a), is 5.0 or less. It is preferable to reduce the heat so that the run-flat durability can be greatly improved.

In addition, according to the invention described in [3] to [7] above, in order to reduce the heat generation of the loss tangent (tan δ) at 28 ° C. to 150 ° C. to 5.0 or less, the rubber composition The filler (B) blended in (a) and the amount thereof are preferably blended in an amount of 50 parts by mass or less of carbon black, and particularly those of FEF grade grade.
Furthermore, according to the inventions described in [8] to [15] above, in order to make the Σ value 5.0 or less, in addition to the amount of filler (50 parts by mass or less) of the component (B). (A) By using a modified conjugated diene polymer (amine-modified, especially primary amine-modified conjugated diene polymer) as a rubber component, it is possible to improve the dispersibility of carbon black and suppress heat generation, and loss tangent ( tan δ) at 28 ° C. to 150 ° C. is 5.0 or less, preferably 5.0 to 3.0.

According to the invention described in [16] above, in the vulcanized rubber physical property of the rubber composition (b) used for the ply coating rubber, the dynamic elastic modulus (E ′) at a dynamic strain of 1% at 25 ° C. It is preferable that it is 8.0 or more.
In this case, the rigidity of the carcass ply is high, and it is possible to further improve the run flat durability by suppressing the bending during the run flat running.
In addition, according to the invention described in [17] above, the low exothermal rubber composition having a dynamic strain of 1% and a loss tangent (tan δ) at 25 ° C. of 0.12 or less in the physical properties of the vulcanized rubber used for the ply coating rubber. In order to obtain the product (b), it is preferable to blend carbon black of FEF grade or less as carbon black as the filler.

In the pneumatic tire of the present invention, a rubber composition (a) having a low elastic modulus and low exothermic property is used for the side reinforcing rubber and / or bead filler, and a rubber composition having a high elastic modulus and low exothermic property is used for the ply coating rubber ( By applying b), heat generation can be greatly suppressed even when subjected to large shear strain and bending strain during run-flat travel.
Usually, the temperature of the vulcanized rubber rises due to run-flat running. As the temperature rises, the mechanical properties (breaking stress, breaking elongation, etc.) drop significantly, leading to breakage. However, since the pneumatic tire according to the present invention can greatly suppress heat generation as described above, the run-flat durability is improved, and the gauge of the reinforcing rubber layer can be further thinned. The run flatness can be secured, and the fuel efficiency is improved by reducing the heat and further reducing the heat generation.
As described above, according to the present invention, it is possible to provide a pneumatic tire with improved run-flat durability and improved rolling resistance and riding comfort during normal running.

It is sectional drawing which shows one embodiment of the pneumatic tire of this invention. It is explanatory drawing for calculating | requiring (SIGMA) tan (delta) (28-150 degreeC) in the vulcanized rubber physical property of a rubber composition.

[Pneumatic tire]
First, the pneumatic tire of the present invention will be described below with reference to the drawings. Drawing 1 is a mimetic diagram showing the section of one embodiment of the pneumatic tire of the present invention.
In FIG. 1, a preferred embodiment of the pneumatic tire of the present invention is toroidally connected between a pair of bead cores 1, 1 ′ (1 ′ is not shown), and both ends of the bead core 1 are located outside the tire from the inside. A carcass layer 2 made of at least one radial carcass ply formed by covering at least one reinforcing cord wound with a ply-coating rubber, and an outer portion disposed on the outer side in the tire axial direction of a side region of the carcass layer 2 Between the tread rubber layer 4 and the crown region of the carcass layer 2, the tread rubber layer 4 which is disposed outside the crown region of the carcass layer 2 in the tire radial direction and forms a contact portion, And a belt layer 5 which forms a reinforcing belt and an inner liner which is arranged on the entire inner surface of the carcass layer 2 to form an airtight film. 6, a bead filler 7 disposed between the body portion of the carcass layer 2 extending from one bead core 1 to the other bead core 1 ′ and a winding portion wound up on the bead core 1, and the side of the carcass layer At least one side reinforcing rubber having a substantially crescent-shaped cross section along the tire rotation axis between the carcass layer 2 and the inner liner 6 from the side of the bead filler 7 to the shoulder area 10 in the region. A pneumatic tire comprising layer 8. In the pneumatic tire of the present invention, the shape of the side reinforcing rubber layer 8 is not limited to this. Moreover, although it does not specifically limit, the range of 6-15 mm is preferable and, as for the maximum thickness of the side reinforcement rubber layer 8, More preferably, it is 7-13 mm. By using each rubber composition according to the present invention for the ply-coating rubber constituting the side reinforcing rubber layer 8 and / or the bead filler 7 and the carcass layer 2 of the pneumatic tire, the pneumatic tire according to the present invention is described above. The effect of this can be achieved.

  In the pneumatic tire of the present invention, in particular, in the vulcanized rubber properties described in detail later on the side reinforcing rubber layer 8 and / or the bead filler 7, dynamic storage elastic modulus (E ′) at a dynamic strain of 1% and 25 ° C. Is a rubber composition (a) having a loss tangent tan δ at 28 ° C. to 150 ° C. of 5.0 or less at a loss tangent tan δ at a dynamic strain of 1% as a ply coating rubber constituting the carcass layer 2 In the physical properties of vulcanized rubber, the loss tangent (tan δ) at 1% dynamic strain at 25 ° C. is 0.12 or less, preferably the dynamic elastic modulus (E ′) at 1% dynamic strain at 25 ° C. is 6. Provided is a pneumatic tire that significantly improves run-flat durability by using the rubber composition (b) of 0.0 MPa or more and improves rolling resistance and riding comfort during normal running. It can be.

  The pneumatic tire of the present invention comprises a bead core, a carcass layer made of one or more carcass plies formed by covering a reinforcing cord with a ply coating rubber, a tread rubber layer, an inner liner, a side rubber layer, a side reinforcing rubber layer, and a bead filler. A pneumatic tire comprising (A) a rubber component and (B) a filler in a side reinforcing rubber and / or a bead filler, and in a physical property of vulcanized rubber, dynamic strain is 1%, dynamic at 25 ° C. A rubber composition (a) having a storage elastic modulus (E ′) of 10 MPa or less, a rubber composition (b) having a dynamic strain of 1% and a loss tangent (tan δ) at 25 ° C. of 0.12 or less is applied to the ply-coated rubber. ).

[Rubber composition (a)]
The rubber composition (a) needs to have a dynamic strain of 1% and a dynamic storage elastic modulus (E ′) at 25 ° C. of 10 MPa or less in order to lower the elastic modulus. (A) It is preferable that 50 mass parts or less of (B) fillers are included with respect to 100 mass parts of rubber components. (B) Carbon black is preferred as the filler, and carbon black is particularly preferably of FEF grade grade. When the dynamic storage elastic modulus at 10% dynamic strain at 25 ° C. exceeds 10 MPa, the tire during normal running It becomes difficult to bend and ride comfort decreases. A preferable dynamic storage elastic modulus (E ′) is 8 MPa or less, and the lower limit thereof is not particularly limited, but is usually about 6.5 MPa.
Furthermore, in order to ensure low heat build-up, it is preferable that in the physical properties of vulcanized rubber, the Σ value at 28 ° C. to 150 ° C. of dynamic strain 1% and loss tangent tan δ is 5.0 or less. More preferably, it can be set to 5.0-3.0.
Next, the (A) rubber component and (B) filler necessary for achieving the above requirements will be described in detail.

((A) rubber component)
As the rubber component (A) in the rubber composition according to the present invention, a modified conjugated diene polymer obtained by modifying a conjugated diene polymer is used, and those containing an amine-modified amine-modified conjugated diene polymer are particularly preferable. Can be used. A material containing such a modified conjugated diene polymer in a proportion of 30% by mass or more, preferably 50% by mass or more can be used. When the rubber component contains 30% by mass or more of the modified conjugated diene polymer, the resulting rubber composition has a low heat generation, the gauge of the reinforcing rubber can be thinned, and normal running without impairing run-flat running durability. A pneumatic tire with improved riding comfort can be provided.

This modified conjugated diene polymer contains at least one of a tin atom, a nitrogen atom, and a silicon atom as a functional group for modification in the molecule.
Preferred examples of the compound containing at least one tin atom in the molecule include tin tetrachloride, tributyltin chloride, dioctyltin dichloride, dibutyltin dichloride and triphenyltin chloride.
Examples of the compound containing at least one nitrogen atom in the molecule include isocyanate compounds, aminobenzophenone compounds, urea derivatives, 4-dimethylaminobenzylideneaniline, dimethylimidazolidinone, and N-methylpyrrolidone.
As the modified conjugated diene-based compound, an amine-modified conjugated diene-based polymer is preferable, and an amino group protected with a protic amino group and / or a detachable group as a functional group for modification in the molecule. A group into which a group is introduced is preferable, and a group into which a functional group containing a silicon atom is further introduced is preferable.
Examples of the functional group containing a silicon atom include a silane group formed by bonding a hydrocarbyloxy group and / or a hydroxy group to a silicon atom.
Such a functional group for modification may be present at any of the polymerization initiation terminal, side chain and polymerization active terminal of the conjugated diene polymer. In the present invention, it is preferably a polymerization terminal, more preferably the same polymerization. A silicon atom having an amino group protected with a protic amino group and / or a detachable group and a hydrocarbyloxy group and / or a hydroxy group, particularly preferably one or two hydrocarbyloxy groups, And / or a silicon atom having a hydroxy group bonded thereto.

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.
As an example of a primary amino group protected with a detachable group (also referred to as a protected primary amino group), an N, N-bis (trimethylsilyl) amino group can be mentioned, As an example of the secondary amino group, an N- (trimethylsilyl) imino group can be mentioned. The N- (trimethylsilyl) imino group-containing group may be an acyclic imine residue or a cyclic imine residue.

  Among the amine-modified conjugated diene polymers described above, the primary amine-modified conjugated diene polymer modified with the primary amino group is obtained by reacting a protected primary amine compound with the active terminal of the conjugated diene polymer. The obtained primary amine-modified conjugated diene polymer modified with a protected primary amino group is preferred.

<Conjugated diene polymer>
The conjugated diene polymer used for modification may be a conjugated diene compound homopolymer or a copolymer of a conjugated diene compound and an aromatic vinyl compound.
Examples of the conjugated diene compound include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, and the like. Is mentioned. These may be used alone or in combination of two or more, and among these, 1,3-butadiene is particularly preferable.
Examples of the aromatic vinyl compound used for copolymerization with the conjugated diene compound include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, and 4-cyclohexylstyrene. 2,4,6-trimethylstyrene and the like. These may be used alone or in combination of two or more, but among these, styrene is particularly preferred.
As the conjugated diene polymer, polybutadiene or styrene-butadiene copolymer is preferable, and polybutadiene is particularly preferable.

  In order to modify the active end of the conjugated diene polymer by reacting with a protected primary amine, it is preferable that the conjugated diene polymer has at least 10% polymer chains having a living property or pseudo-living property. Examples of such a polymerization reaction having a living property include a reaction in which an organic alkali metal compound is used as an initiator and a conjugated diene compound alone or an conjugated diene compound and an aromatic vinyl compound are subjected to anionic polymerization in an organic solvent.

  As the organic alkali metal compound used as an initiator for the above-mentioned anionic polymerization, an organic lithium compound is preferable. The organolithium compound 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 has polymerization activity. A conjugated diene polymer as a site is obtained. When the latter lithium amide compound is used, a conjugated diene polymer having a nitrogen-containing group at the polymerization initiation terminal and the other terminal being a polymerization active site is obtained.

  As the hydrocarbyl lithium, those having a hydrocarbyl group having 2 to 20 carbon atoms are preferable, for example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-octyl lithium, n-decyl. Examples include lithium, phenyllithium, 2-naphthyllithium, 2-butylphenyllithium, 4-phenylbutyllithium, cyclohexyllithium, cyclobenthyllithium, and reactive organisms of diisopropenylbenzene and butyllithium. Of these, n-butyllithium is particularly preferred.

On the other hand, examples of the lithium amide compound include lithium hexamethylene imide, lithium pyrrolidide, lithium piperide, lithium heptamethylene imide, lithium dodecamethylene imide, lithium dimethyl amide, lithium diethyl amide, lithium dibutyl amide, lithium dipropyl amide, 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 a secondary amine and a lithium compound can be used for polymerization, but can also be prepared in a polymerization system (in-situ). The amount of the polymerization initiator used is preferably selected in the range of 0.2 to 20 mmol per 100 g of monomer.

A method for producing a conjugated diene polymer by anionic polymerization using the organolithium compound as a polymerization initiator is not particularly limited, and a conventionally known method can be used.
Specifically, in an organic solvent inert to the reaction, for example, a hydrocarbon solvent such as an aliphatic, alicyclic, or aromatic hydrocarbon compound, the conjugated diene compound or the conjugated diene compound and the aromatic vinyl compound are If desired, a conjugated diene polymer having an active terminal can be obtained by anionic polymerization in the presence of a randomizer to be used, if desired, using a lithium compound as a polymerization initiator.
In addition, when an organic lithium compound is used as a polymerization initiator, it has not only a conjugated diene polymer having an active end but also an active end, compared to the case of using a catalyst containing the lanthanum series rare earth element compound described above. A copolymer of a conjugated diene compound and an aromatic vinyl compound can also be obtained efficiently.

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 monomer concentration in the solvent is preferably 5 to 50% by mass, more preferably 10 to 30% by mass. When copolymerization is performed using a conjugated diene compound and an aromatic vinyl compound, the content of the aromatic vinyl compound in the charged monomer mixture is preferably in the range of 55% by mass or less.

  The randomizer used as desired is a control of the microstructure of the conjugated diene polymer, such as an increase in 1,2 bonds in the butadiene portion in the butadiene-styrene copolymer, an increase in 3,4 bonds in the isoprene polymer, or the like. It is a compound having an effect of controlling the composition distribution of monomer units in a conjugated diene compound-aromatic vinyl compound copolymer, for example, randomizing butadiene units and styrene units in a butadiene-styrene copolymer. The randomizer is not particularly limited, and any one of known compounds generally used as a conventional randomizer can be appropriately selected and used. Specifically, dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, oxolanylpropane oligomers [especially those containing 2,2-bis (2-tetrahydrofuryl) -propane, etc.], triethylamine, pyridine , N-methylmorpholine, N, N, N ′, N′-tetramethylethylenediamine, ethers such as 1,2-dipiperidinoethane, and tertiary amines. Further, potassium salts such as potassium tert-amylate and potassium tert-butoxide, and sodium salts such as sodium tert-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.

<Modifier>
In the present invention, the active end of the conjugated diene polymer having an active end obtained as described above has, as a modifier, for example, a tin atom as tin tetrachloride, tributyltin chloride, dioctyltin dichloride, dibutyltin dichloride. Or by a tin compound such as triphenyltin chloride. The nitrogen atom is an isocyanate compound such as 2,4-tolylene diisocyanate or diisocyanate diphenylmethane; an aminobenzophenone compound such as 4,4′bis (diethylamino) -benzophenone or 4- (dimethylamino) benzophenone; -Urea derivatives such as dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, 1,3-dimethyl-3,4,5,6-tetrahydropyrimidine, and other 4-dimethylaminobenzylideneanilines , Dimethylimidazolidinone, N-methylpyrrolidone, and other nitrogen-containing compounds. Silicon atoms can be introduced by a terminal modifier such as alkoxysilane or aminoalkoxysilane. Specifically, examples of the epoxy group-containing alkoxysilane compound include 2-glycidoxyethyltrimethoxysilane, 2-glycidoxyethyltriethoxysilane, (2-glycidoxyethyl) methyldimethoxysilane, 3- Glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, (3-glycidoxypropyl) methyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3 4-epoxycyclohexyl) ethyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl (methyl) dimethoxysilane, and the like.

As a particularly preferable modifier, a primary amine-modified conjugated diene polymer can be produced by reacting a protected primary amine compound. As the protected primary amine compound, an alkoxysilane compound having a protected primary amino group is suitable.
Examples of the alkoxysilane compound having a protected primary amino group used as the modifier include N, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane, 1-trimethylsilyl-2,2-dimethoxy-1-aza-2. -Silacyclopentane, N, N-bis (trimethylsilyl) aminopropyltrimethoxysilane, N, N-bis (trimethylsilyl) aminopropyltriethoxysilane, N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane, N, N-bis (trimethylsilyl) aminoethyltrimethoxysilane, N, N-bis (trimethylsilyl) aminoethyltriethoxysilane, N, N-bis (trimethylsilyl) aminoethylmethyldimethoxysilane and N, N-bis (trimethylsilyl) Aminoethylmethyldiethoxysilane and the like, preferably N, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane, N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane or 1-trimethylsilyl-2 , 2-dimethoxy-1-aza-2-silacyclopentane.

Moreover, as a modifier, 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 (pyrrolidine- 2-yl) propyl (methyl) diethoxysilane, N-trimethylsilyl (piperidin-2-yl) propyl (methyl) dimethoxysilane, N-trimethylsilyl (piperidin-2-yl) propyl (methyl) diethoxysila N-trimethylsilyl (imidazol-2-yl) propyl (methyl) dimethoxysilane, N-trimethylsilyl (imidazol-2-yl) propyl (methyl) diethoxysilane, N-trimethylsilyl (4,5-dihydroimidazol-5-yl) ) Alkoxysilane compounds having a protected secondary amino group such as propyl (methyl) dimethoxysilane, N-trimethylsilyl (4,5-dihydroimidazol-5-yl) propyl (methyl) diethoxysilane; N- (1,3 -Dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine, N- (1-methylethylidene) -3- (triethoxysilyl) -1-propanamine, N-ethylidene-3- (triethoxy Silyl) -1-propanamine, N- (1-methylpropiyl) Den) -3- (triethoxysilyl) -1-propanamine, N- (4-N, N-dimethylaminobenzylidene) -3- (triethoxysilyl) -1-propanamine, N- (cyclohexylidene) Alkoxysilane compounds having an imino group such as -3- (triethoxysilyl) -1-propanamine; 3-dimethylaminopropyl (triethoxy) silane, 3-dimethylaminopropyl (trimethoxy) silane, 3-diethylaminopropyl (triethoxy) Silane, 3-diethylaminopropyl (trimethoxy) silane, 2-dimethylaminoethyl (triethoxy) silane, 2-dimethylaminoethyl (trimethoxy) silane, 3-dimethylaminopropyl (diethoxy) methylsilane, 3-dibutylaminopropyl (triethoxy) silane Examples thereof include alkoxysilane compounds having an amino group such as lan.
These modifiers may be used individually by 1 type, and may be used in combination of 2 or more types. The modifier may be a partial condensate.
Here, the partial condensate means a product in which a part (not all) of the modifier SiOR is SiOSi bonded by condensation.

In the modification reaction with the modifying agent, the amount of the modifying agent is preferably 0.5 to 200 mmol / kg · conjugated diene polymer. The amount used is more preferably 1 to 100 mmol / kg · conjugated diene polymer, and particularly preferably 2 to 50 mmol / kg · conjugated diene polymer. Here, the conjugated diene polymer means the mass of only a polymer that does not contain an additive such as an anti-aging agent added during or after the production. By making the usage-amount of a modifier into the said range, it is excellent in the dispersibility of a filler, especially carbon black, and the fracture resistance after vulcanization and low heat build-up are improved.
The method of adding the modifier is not particularly limited, and examples thereof include a method of adding all at once, a method of adding in divided portions, a method of adding continuously, and the like. preferable.
Further, the modifier can be bonded to any of the polymer main chain and the side chain other than the polymerization initiation terminal and the polymerization termination terminal, but it can suppress the loss of energy from the polymer terminal and improve the low heat generation. 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. Furthermore, as a condensation accelerator, an alkoxide, a carboxyl containing at least one metal selected from the group consisting of titanium (Ti), zirconium (Zr), bismuth (Bi), aluminum (Al), and tin (Sn). It is preferably an acid salt or an acetylacetonate complex salt.
The condensation accelerator used here can be added before the modification reaction, but is preferably added to the modification reaction system during and / or after the modification reaction. When added before the denaturation reaction, a direct reaction with the active end may occur, and a hydrocarbyloxy group having a protected primary amino group at the active end may not be introduced.
The addition time of the condensation accelerator is usually 5 minutes to 5 hours after the start of the modification reaction, preferably 15 minutes to 1 hour after the start of the modification reaction.

  Specific examples of the condensation accelerator include tetramethoxytitanium, tetraethoxytitanium, tetra-n-propoxytitanium, tetraisopropoxytitanium, tetra-n-butoxytitanium, tetra-n-butoxytitanium oligomer, tetra-sec- Butoxytitanium, tetra-tert-butoxytitanium, tetra (2-ethylhexyl) titanium, bis (octanediolate) bis (2-ethylhexyl) titanium, tetra (octanediolate) titanium, titanium lactate, titanium dipropoxybis (triethanol Aminate), titanium dibutoxybis (triethanolaminate), titanium tributoxy systemate, titanium tripropoxy systemate, titanium ethyl Sildiolate, Titanium tripropoxyacetylacetonate, Titanium dipropoxybis (acetylacetonate), Titanium tripropoxyethylacetoacetate, Titaniumpropoxyacetylacetonatebis (ethylacetoacetate), Titanium tributoxyacetylacetonate, Titanium dibutoxybis ( Acetylacetonate), titanium tributoxyethyl acetoacetate, titanium butoxyacetylacetonate bis (ethylacetoacetate), titanium tetrakis (acetylacetonate), titanium diacetylacetonate bis (ethylacetoacetate), bis (2-ethylhexano) Ate) titanium oxide, bis (laurate) titanium oxide, bis (naphthene) ) 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 Examples thereof include compounds containing titanium such as (stearate) titanium, tetrakis (oleate) titanium, and tetrakis (linoleate) titanium.

  Examples of the condensation accelerator include tris (2-ethylhexanoate) bismuth, tris (laurate) bismuth, tris (naphthenate) 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-ethylhexyl) 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 (naphthenate) zirconium oxide, bis (stearate) zirconium oxide, bis (oleate) zirconium oxide, bis (linoleate) zirconium oxide, tetrakis (2-ethylhexanoate) zirconium, tetrakis (laurate) zirconium, tetrakis (naphthenate) Zirconium, tetrakis (stearate) zirconium, tetrakis (oleate) zirconium, Tetrakis (linolate) zirconium and the like.

  Also, triethoxyaluminum, tri-n-propoxyaluminum, triisopropoxyaluminum, tri-n-butoxyaluminum, tri-sec-butoxyaluminum, tri-tert-butoxyaluminum, tri (2-1 ethylhexyl) aluminum, aluminum di Butoxy systemate, aluminum dibutoxyacetylacetonate, aluminum butoxybis (acetylacetonate), aluminum dibutoxyethylacetoacetate, aluminum tris (acetylacetonate), aluminum tris (ethylacetoacetate), tris (2-ethylhexanoate) Ate) aluminum, tris (laurate) aluminum, tris (naphthenate) aluminum, tris (stearate) aluminum, Squirrel (oleate) aluminum, tris (linolate) aluminum, and the like.

Of the above condensation accelerators, titanium compounds are preferable, and titanium metal alkoxides, titanium metal carboxylates, or titanium metal acetylacetonate complex salts are particularly preferable.
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.

<Modified conjugated diene polymer>
The modified conjugated diene polymer thus obtained has a Mooney viscosity (ML _{1 + 4} , 100 ° C.) of preferably 10 to 150, more preferably _{15 to} 100. When the Mooney viscosity is less than 10, sufficient rubber physical properties such as fracture resistance are not obtained, and when it exceeds 150, workability is poor and it is difficult to knead with the compounding agent.
The Mooney-viscosity (ML _{1 + 4} , 130 ° C.) of the unvulcanized rubber composition according to the present invention containing the modified conjugated diene polymer is preferably 10 to 150, more preferably 30 to 100. is there.
The modified conjugated diene polymer used in the rubber composition according to the present invention has a ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn), that is, the molecular weight distribution (Mw / Mn) is 1. It is preferable that it is -3, and it is more preferable that it is 1.1-2.7.
By making the molecular weight distribution (Mw / Mn) of the modified conjugated diene polymer within the above range, even if the modified conjugated diene polymer is blended with the rubber composition, the workability of the rubber composition may be reduced. And kneading is easy, and the physical properties of the rubber composition can be sufficiently improved.

The modified conjugated diene polymer used in the rubber composition according to the present invention preferably has a number average molecular weight (Mn) of 100,000 to 500,000, preferably 150,000 to 300,000. Is more preferable. By making the number average molecular weight of the modified conjugated diene polymer within the above range, the elastic modulus of the vulcanizate is reduced and the increase in hysteresis loss is suppressed to obtain excellent fracture resistance, and the modified conjugated diene polymer Excellent kneading workability of the rubber composition containing can be obtained.
The modified conjugated diene polymer used in the rubber composition according to the present invention may be used singly or in combination of two or more.

<Other rubber components>
(A) In the rubber component, examples of the rubber component used in combination with the modified conjugated diene polymer include natural rubber and other diene synthetic rubbers. Examples of other diene synthetic rubbers include styrene-butadiene copolymer. Polymer (SBR), polybutadiene (BR), polyisoprene (IR), styrene-isoprene copolymer (SIR), butyl rubber (IIR), halogenated butyl rubber, ethylene-propylene-diene terpolymer (EPDM) and These mixtures are mentioned. Further, some or all of the other diene-based synthetic rubber is more preferably a diene-based modified rubber having a branched structure by using a polyfunctional modifier, for example, a modifier such as tin tetrachloride. .

((B) Filler)
In the rubber composition which concerns on this invention, it is preferable to use a filler as a (B) component in the ratio of 50 mass parts or less with respect to 100 mass parts of above-mentioned (A) rubber components. When the amount of the filler exceeds 50 parts by mass, effects such as sufficient low heat build-up and low elasticity are not exhibited, and in the vulcanized rubber properties of the resulting rubber composition, dynamic strain described later is 1%, 25 The dynamic storage elastic modulus (E ′) at 0 ° C. may not be 10 MPa or less. If the amount of the filler is too large, the Σ value at 28 ° C. to 150 ° C. of the loss tangent tan δ described later may not be 5.0 or less in the physical properties of the vulcanized rubber of the resulting rubber composition. Therefore, the preferable amount of the filler is 50 to 30 parts by mass, and more preferably 45 to 40 parts by mass. When the amount of the filler is 30 parts by weight or less, the breaking strength of the rubber is lowered, and the run-flat durability is remarkably impaired.

The filler is carbon black, silica and general formula (I)
nM · xSiO _y · zH ₂ O (I)
[Wherein, M is at least selected from metals selected from aluminum, magnesium, titanium, calcium and zirconium, oxides or hydroxides of these metals, hydrates thereof, and carbonates of the metals. N, x, y, and z are each an integer of 1 to 5, an integer of 0 to 10, an integer of 2 to 5, and an integer of 0 to 10. ] It is at least 1 type chosen from the inorganic fillers represented by this.
Here, as the carbon black, in order that the vulcanized rubber properties of the obtained rubber composition satisfy the above vulcanized rubber properties, for example, various grades of carbon black such as SAF, HAF, ISAF, FEF, GPF, etc. Can be used alone or in admixture. Of these, FEF grade carbon black is the best choice.
Silica is not particularly limited, but wet silica, dry silica, and colloidal silica are preferable. These can be used alone or in combination.

Specific examples of the inorganic filler represented by the general formula (I) include alumina (Al ₂ O ₃ ) such as γ-alumina and α-alumina, and alumina monohydrate (Al ₂ O such as boehmite and diaspore). ₃ · H ₂ O), Gibbsite, Bayerite, etc. Aluminum hydroxide [Al (OH) ₃ ], Aluminum carbonate [Al ₂ (CO ₃ ) ₂ ], Magnesium hydroxide [Mg (OH) ₂ ], Magnesium oxide ( MgO), magnesium carbonate (MgCO _3), talc _{(3MgO · 4SiO 2 · H 2} O), attapulgite _{(5MgO · 8SiO 2 · 9H 2} O), titanium white (TiO _2), titanium black (TiO _2n-1), calcium oxide (CaO), calcium hydroxide [Ca (OH) _2], magnesium aluminum oxide _{(MgO · Al 2 O 3)} , clay _{(Al 2 O 3 · 2SiO 2} ), Kao Down _{(Al 2 O 3 · 2SiO 2} · 2H 2 O), pyrophyllite _{(Al 2 O 3 · 4SiO 2} · H 2 O), bentonite _{(Al 2 O 3 · 4SiO 2} · 2H 2 O), aluminum silicate (Al ₂ SiO ₅ , Al ₄ · 3SiO ₄ · 5H ₂ O, etc.), magnesium silicate (Mg ₂ SiO ₄ , MgSiO ₃ etc.), calcium silicate (Ca ₂ · SiO ₄ etc.), aluminum calcium silicate (Al ₂ O ₃ · CaO · 2SiO ₂ etc.), magnesium calcium silicate (CaMgSiO ₄ ), calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO ₂ ), zirconium hydroxide [ZrO (OH) ₂ · nH ₂ O], carbonic acid zirconium _{[Zr (CO 3) 2]} , crystalline aluminosilicate containing hydrogen, alkali metal or alkaline earth metal which corrects a charge as various zeolites There can be used.
The inorganic filler represented by the general formula (I) includes at least one selected from the group consisting of aluminum metal, aluminum oxide or hydroxide, hydrates thereof, and aluminum carbonate. preferable.
Among these, as the filler (B), carbon black and silica are preferable, and carbon black is particularly preferable.

[Rubber composition (b)]
Next, the rubber composition (b) will be described. The rubber composition (b) is applied to the ply coating rubber, and the rubber composition (b) having a loss tangent (tan δ) at 1% strain at 25 ° C. of 0.12 or less in physical properties of the vulcanized rubber is applied. is required. 0.10 or less is particularly preferable. Although there is no restriction | limiting in particular about the lower limit, Usually, it is about 0.05. The rubber composition (b) having a loss tangent (tan δ) at 1% strain at 25 ° C. of 0.12 or less is excellent in low heat build-up, so that heat generation during run-flat running is small, carcass ply heat generation, and thus tires. Heat generation when viewed as a whole can be suppressed. Therefore, by applying the rubber composition (b) to the carcass ply coating rubber, the temperature increase of the side reinforcing rubber layer during run flat running is suppressed, the destruction of the side reinforcing rubber layer is suppressed, and the tire Run-flat durability can be improved.

  The rubber composition (b) applied to the carcass ply coating rubber preferably has a dynamic elastic modulus (E ′) at 1% strain at 25 ° C. of 6.0 MPa or more. In this case, the rigidity of the carcass ply is high, and it is possible to further improve the tire run-flat durability by suppressing the deflection of the tire during the run-flat running. The upper limit of the dynamic elastic modulus (E ′) is not particularly limited, but is usually about 15.0 MPa.

  As the rubber composition (b) applied to the coating rubber, a rubber composition obtained by blending a rubber component with a low grade carbon black of FEF or lower is preferable. In general, high-grade carbon black is used for the carcass ply coating rubber in order to improve the carcass reinforcement. It is preferable to use black. Moreover, the workability | operativity in the kneading | mixing of a rubber composition can also be improved by using carbon black below FEF grade. Examples of the carbon black of FEF or lower include GPF class, SRF class carbon black, etc. in addition to FEF class carbon black.

  Examples of the rubber component of the rubber composition (b) include natural rubber (NR) and diene synthetic rubbers such as styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), and polyisoprene rubber (IR). These rubber components may be used alone or in a blend of two or more.

Further, the rubber composition according to the present invention includes various chemicals usually used in the rubber industry, for example, a vulcanizing agent, a vulcanization accelerator, a process oil, an aging, as desired, as long as the effects of the present invention are not impaired. An inhibitor, 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 rupture strength, wear resistance, and low heat build-up of the vulcanized rubber may be reduced. If the amount exceeds 10.0 parts by mass, the rubber elasticity is lost.
The vulcanization accelerator that can be used in the present invention is not particularly limited, and examples thereof include M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), and CZ (N-cyclohexyl-2-benzothiazyl). Thiophene vulcanization accelerators such as thiazoles such as sulfenamide), guanidines such as DPG (diphenylguanidine), or thiurams such as TOT (tetrakis (2-ethylhexyl) thiuram disulfide). 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 (A) rubber component.

Examples of the process oil used as a softening agent 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 (A). Can be suppressed.
Furthermore, examples of the antioxidant that can be used in the rubber composition according to the present invention include 3C (N-isopropyl-N′-phenyl-p-phenylenediamine, 6C [N- (1,3-dimethylbutyl) -N ′). -Phenyl-p-phenylenediamine], AW (6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline), high-temperature condensate of diphenylamine and acetone, etc. (A) 0.1-5.0 mass part is preferable with respect to 100 mass parts of rubber components, More preferably, it is 0.3-3.0 mass part.

<Measuring method of dynamic storage elastic modulus (E ')>
A sheet having a width of 5 mm and a length of 40 mm was cut out from a slab sheet having a thickness of 2 mm obtained by vulcanizing the side inner layer rubber composition at 160 ° C. for 12 minutes, and used as a sample. This sample is measured using a spectrometer manufactured by Ueshima Seisakusho Co., Ltd. under conditions of a distance between chucks of 10 mm, an initial strain of 200 μm, a dynamic strain of 1%, a frequency of 52 Hz, and a measurement temperature of 25 ° C.

Further, as the physical properties of the vulcanized rubber, it is necessary that the Σ value [Σ tan δ (28 to 150 ° C.)] at 28 ° C. to 150 ° C. of the loss tangent tan δ is 5.0 or less. When the Σ value of tan δ exceeds 5.0, heat generation of the tire during run flat running is large, and the run flat running durability of the tire is lowered. The lower limit of Σtan δ (28 to 150 ° C.) is not particularly limited, but is usually about 3.
The Σtanδ (28 to 150 ° C.) is a value measured by the following method.
<Measuring method of Σtan δ (28 to 150 ° C.)>
A sheet having a width of 5 mm and a length of 40 mm was cut out from a slab sheet having a thickness of 2 mm obtained by vulcanizing the rubber composition at 160 ° C. for 12 minutes to prepare a sample. About this sample, a tangent loss tan δ was measured under the measurement conditions of a distance between chucks of 10 mm, an initial strain of 200 μm, a dynamic strain of 1%, a frequency of 52 Hz, and a measurement start temperature of 25 to 200 ° C. using a spectrometer manufactured by Ueshima Seisakusho. As shown in FIG. 2, the relationship between temperature and tan δ is graphed, the area of the shaded portion is obtained, and the value is Σ tan δ (28 to 150 ° C.).

(Preparation of rubber composition, production of pneumatic tire)
The rubber composition according to the present invention is obtained by kneading using a kneading machine such as a Banbury mixer, a roll, an internal mixer or the like according to the above compounding prescription, vulcanized after molding, and in FIG. It is used as a ply coating rubber constituting the side reinforcing rubber layer 8 and / or the bead filler 7 and the carcass layer 2 of the pneumatic tire.
As described above, the tire of the present invention is produced by using the rubber composition (a) or (b) according to the present invention for the side reinforcing rubber layer 8 and / or the bead filler 7 and the ply coating rubber. Manufactured by the method. That is, as described above, the rubber composition according to the present invention containing various chemicals is processed into each member at an unvulcanized stage, and pasted and molded by a normal method on a tire molding machine, and a raw tire is molded. Is done. The green tire is heated and pressed in a vulcanizer to obtain a tire.
The pneumatic tire of the present invention thus obtained has improved rolling resistance and riding comfort during normal running without impairing run-flat durability.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Various characteristics were measured according to the following methods.
<< Physical Properties of Unmodified or Modified Conjugated Diene Polymer >>
<Microstructure analysis method>
The vinyl bond content (%) was measured by an infrared method (Morero method).
<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 primary amino group content (mmol / kg)>
First, the polymer was dissolved in toluene, and then the amino group-containing compound not bound to the polymer was separated from the rubber by precipitation in a large amount of methanol, followed by drying. Using this treated polymer as a sample, the total amino group content was quantified by the “total amine value test method” described in JIS K7237. Subsequently, the contents of the secondary amino group and the tertiary amino group were quantified by “acetylacetone blocked method” using the polymer subjected to the above treatment as a sample. As a solvent for dissolving the sample, o-nitrotoluene was used, acetylacetone was added, and potentiometric titration was performed with a perchloracetic acid solution. The primary amino group content (mmol) is obtained by subtracting the secondary amino group content and tertiary amino group content from the total amino group content, and divided by the polymer mass used in the analysis to bind to the first polymer. The amino group content (mmol / kg) was determined.

<< Physical properties of vulcanized rubber of rubber composition >>
<Measurement of Loss Tangent (tan δ) and Dynamic Elastic Modulus (E ′)>
A sample having a width of 5 mm and a length of 40 mm was cut out from a slab sheet having a thickness of 2 mm obtained by vulcanizing each rubber composition under the conditions of 160 ° C. × 12 minutes. Using a spectrometer manufactured by Ueshima Seisakusho Co., Ltd., rubber was used under the conditions of the distance between chucks: 10 mm, initial strain: 200 μm, dynamic strain: 1%, frequency: 52 Hz, measurement temperature: 25 ° C. The loss tangent (tan δ) and dynamic elastic modulus (E ′) of the composition were measured.
<Measurement of Σ value of loss tangent tan δ at 28 ° C. to 150 ° C. [Σ tan δ (28 to 150 ° C.)]
A sheet having a width of 5 mm and a length of 40 mm was cut out from a slab sheet having a thickness of 2 mm obtained by vulcanizing the rubber composition at 160 ° C. for 12 minutes to prepare a sample. About this sample, the loss tangent tan δ is measured under the measurement conditions of a distance between chucks of 10 mm, an initial strain of 200 μm, a dynamic strain of 1%, a frequency of 52 Hz, and a measurement start temperature of 25 to 200 ° C. using a spectrometer manufactured by Ueshima Seisakusho. As shown in FIG. 2, the relationship between temperature and tan δ is graphed, the area of the shaded portion is obtained, and the value is Σ tan δ (28 to 150 ° C.).

<< Evaluation of pneumatic tire >>
<Ride comfort>
Each test tire was mounted on a passenger car, and a feeling test of ride comfort was conducted by two specialized drivers, and a score of 1-10 was assigned to obtain an average value. The larger the value, the better the ride comfort. In addition, the pass line of riding comfort is 7 or more.
<Runflat durability>
Each test tire (passenger car radial tire of tire size 215 / 45ZR17) is assembled with rims at normal pressure, filled with 230 kPa of internal pressure, left in a room at 38 ° C. for 24 hours, then the valve core is removed to increase the internal pressure. The drum running test was performed under the conditions of a pressure of 4.17 kN (425 kg), a speed of 89 km / h, and an indoor temperature of 38 ° C. as atmospheric pressure. The travel distance until failure of each test tire was measured, and the travel distance of Comparative Example 1 was taken as 100, and the index was displayed by the following formula. The larger the index, the better the run flat durability.
Run-flat durability (index) = (travel distance of test tire / travel distance of tire of Comparative Example 1) × 100

Production Example 1 Production of primary amine-modified polybutadiene (1) Polybutadiene In a nitrogen-substituted 5 L autoclave, 1.4 kg of cyclohexane, 250 g of 1,3-butadiene, 2,2-ditetrahydrofurylpropane (0.0285 mmol) cyclohexane under nitrogen. The solution was poured as a solution, and 2.85 mmol of n-butyllithium was added thereto, followed by polymerization in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The reaction conversion of 1,3-butadiene was almost 100%. This polymer solution was drawn into a methanol solution containing 1.3 g of 2,6-di-tert-butyl-p-cresol, and after the polymerization was stopped, the solvent was removed by steam stripping and dried with a roll at 110 ° C. Thus, polybutadiene was obtained. The resulting polybutadiene was measured for microstructure (vinyl bond amount), weight average molecular weight (Mw), and molecular weight distribution (Mw / Mn). As a result, the vinyl bond content was 14%, Mw was 150,000, and Mw / Mn was 1.1.

(2) Production of primary amine-modified polybutadiene N, N-bis in which the polymer solution obtained in (1) above is maintained at a temperature of 50 ° C. without deactivating the polymerization catalyst, and the primary amino group is protected. (Trimethylsilyl) aminopropylmethyldiethoxysilane (1129 mg, 3.364 mmol) was added, and the modification reaction was performed for 15 minutes. 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 by a rip roll adjusted to 110 ° C. to obtain primary amine-modified polybutadiene. The resulting modified polybutadiene was measured for microstructure (vinyl bond amount), weight average molecular weight (Mw), molecular weight distribution (Mw / Mn), and primary amino group content. As a result, the vinyl bond content was 14%, Mw was 150,000, Mw / Mn was 1, 2, and the primary amino group content was 4.0 mmol / kg.

Production Example 2 Production of Secondary Amine-Modified Polybutadiene In Production Example 1 (2), secondary amine N-methyl-N- (trimethylsilyl) aminopropylmethyldiethoxysilane was used as the modifier in (2) above. Based on this, a modification reaction was carried out to obtain a secondary amine-modified polybutadiene.

Production Example 3 Production of Tertiary Amine Modified Polybutadiene In Production Example 1 (2), a modification reaction is performed based on the above (2) using DMAPES: 3-dimethylaminopropyl (diethoxy) methylsilane as a modifier. Polybutadiene was obtained.

Rubber composition for side reinforcing rubber (a) A to E, Rubber composition for ply coating rubber (b) F to G
Five types of rubber compositions (a) having the compounding compositions of the side-reinforcing rubber compositions A to E shown in Table 1 were prepared, and vulcanized rubber properties, that is, dynamic storage elastic modulus (E ′). And Σtan δ (28 to 150 ° C.) were obtained. The evaluation results are shown in Table 1.

[note]
1) Natural rubber: TSR20
2) Unmodified polybutadiene: Production Example 1 (1) Product obtained by production of polybutadiene 3) Primary amine-modified polybutadiene: Obtained in Production Example 1 4) Secondary amine-modified polybutadiene: Obtained in Production Example 2 5) Tertiary amine-modified polybutadiene: obtained in Production Example 3 6) Carbon black: FEF (N550), “Asahi # 60” manufactured by Asahi Carbon Co., Ltd.
7) Process oil: Aromatic oil, “Aromax # 3” manufactured by Fuji Kosan Co., Ltd.
8) Anti-aging agent 6C: N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, “NOCRACK 6C” manufactured by Ouchi Shinsei Chemical Co., Ltd.
9) Vulcanization accelerator CZ: N-cyclohexyl-2-benzothiazylsulfenamide, “Noxeller CZ” manufactured by Ouchi Shinsei Chemical Co., Ltd.
10) Vulcanization accelerator TOT: Tetrakis (2-ethylhexyl) thiuram disulfide, “Noxeller TOT-N” manufactured by Ouchi Shinsei Chemical Co., Ltd.

  Next, two types of rubber compositions (b) having the compounding compositions of the ply coating rubber compositions F to G shown in Table 2 were prepared, and their respective vulcanized rubber properties, that is, dynamic storage elastic modulus (E ') And loss tangent (tan δ) were obtained. The evaluation results are shown in Table 2.

[note]
11) SBR: JSR SBR1778, 25% styrene-containing styrene-butadiene copolymer 12) Carbon black: N330 (HAF), Asahi Carbon Co., Ltd. 13) Vulcanization accelerator DM; Dibenzothiazyl disulfide "Noxeller DM"

Examples 1-6, Comparative Examples 1-9
Table 5-1, 2 and 3 show five types of rubber compositions for side reinforcing rubber (a) on the side reinforcing rubber layer shown in FIG. 1 and two types of rubber composition (b) on the coating rubber constituting the carcass layer. A radial tire for a passenger car having a tire size of 215 / 45ZR17 was manufactured according to a conventional method. Further, the gauge of the side reinforcing rubber layer was also changed according to Tables 3-1, 2 and 3 above.
Using the obtained 15 types of tires, the riding comfort and run-flat durability were evaluated. The evaluation results are shown in Tables 3, 1 and 3.

  The pneumatic tire of the present invention comprises a rubber composition (a) having a low elastic modulus and a low exothermic property for the side reinforcing rubber and / or bead filler, and a rubber composition (b) having a high elastic modulus and a low exothermic property for the ply coating rubber. ), It is possible to improve the rolling resistance and riding comfort during normal driving without impairing the run-flat durability, and can be suitably applied to a side-reinforced run-flat tire or the like.

1 Bead core 2 Carcass layer 3 Side rubber layer 4 Tread rubber layer 5 Belt layer 6 Inner liner 7 Bead filler 8 Side reinforcing rubber layer 10 Shoulder area

Claims (17)

  A pneumatic tire comprising a bead core, a carcass layer made of one or more carcass plies formed by covering a reinforcing cord with a ply coating rubber, a tread rubber layer, an inner liner, a side rubber layer, a side reinforcing rubber layer, and a bead filler. The side reinforcing rubber and / or bead filler contains (A) a rubber component and (B) a filler, and the physical properties of vulcanized rubber have a dynamic storage elastic modulus (E ′) at 25 ° C. of dynamic strain of 1%. A rubber composition (a) having a pressure of 10 MPa or less is used, and a rubber composition (b) having a dynamic strain of 1% and a loss tangent (tan δ) at 25 ° C. of 0.12 or less is used for the ply coating rubber. Pneumatic tires.   The pneumatic tire according to claim 1, wherein in the rubber composition (a), a Σ value at 28 ° C to 150 ° C of a loss tangent (tan δ) at a dynamic strain of 1%, which is a physical property of vulcanized rubber, is 5.0 or less. .   The pneumatic tire according to claim 1 or 2, wherein in the rubber composition (a), the amount of the filler of the component (B) is 50 parts by mass or less with respect to 100 parts by mass of the rubber component (A). The filler of component (B) is carbon black, silica and general formula (I)
nM · xSiO _y · zH ₂ O (I)
[Wherein, M is at least selected from metals selected from aluminum, magnesium, titanium, calcium and zirconium, oxides or hydroxides of these metals, hydrates thereof, and carbonates of the metals. N, x, y, and z are each an integer of 1 to 5, an integer of 0 to 10, an integer of 2 to 5, and an integer of 0 to 10. ]
The pneumatic tire according to any one of claims 1 to 3, wherein the pneumatic tire is at least one selected from the group consisting of inorganic fillers.   The pneumatic tire according to claim 4, wherein the filler of component (B) is carbon black.   6. The pneumatic tire according to claim 5, wherein the carbon black is at least one selected from FEF grade, FF grade, HAF grade, ISAF grade and SAF grade.   The pneumatic tire according to claim 6, wherein the carbon black is FEF grade.   The pneumatic tire according to any one of claims 1 to 7, wherein in the rubber composition (a), the rubber component (A) contains a modified conjugated diene polymer.   The pneumatic tire according to claim 8, wherein the modified conjugated diene polymer is an amine-modified conjugated diene polymer.   The pneumatic tire according to claim 9, wherein the amine-modified conjugated diene polymer is a protic amine-modified conjugated diene polymer.   The pneumatic tire according to claim 9 or 10, wherein the amine-modified conjugated diene polymer is a primary amine-modified conjugated diene polymer.   The pneumatic tire according to claim 11, wherein the primary amine-modified conjugated diene polymer is obtained by reacting a protected primary amine compound with an active terminal of the conjugated diene polymer.   13. The conjugated diene polymer is obtained by anionic polymerization of a conjugated diene compound alone or a conjugated diene compound and an aromatic vinyl compound in an organic solvent using an organic alkali metal compound as an initiator. Pneumatic tires.   The pneumatic tire according to claim 13, wherein the conjugated diene polymer is polybutadiene.   The pneumatic tire according to any one of claims 13 to 14, wherein the protected primary amine compound is N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane.   2. The pneumatic tire according to claim 1, wherein in the physical properties of the vulcanized rubber of the rubber composition (b), the dynamic elastic modulus (E ′) at a dynamic strain of 1% at 25 ° C. is 6.0 MPa or more.   The pneumatic tire according to claim 1 or 16, wherein the rubber composition (b) applied to the coating rubber is blended with carbon black of FEF grade or less with respect to the rubber component.

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