JP5498800B2 - Pneumatic tire - Google Patents

Description

  The present invention provides a rubber composition having a vulcanized rubber characteristic in which a dynamic storage elastic modulus (E ′) is a specific value or less and a Σ value of a loss tangent tan δ at 28 ° C. to 150 ° C. is a specific value or less. In particular, it is used for a side rubber reinforcing layer and / or a bead filler, and further, a rubber composition having a vulcanized rubber physical property of 1% dynamic strain and loss tangent (tan δ) at 25 ° C. of a specific value or less is used for the side rubber layer. The present invention relates to a pneumatic tire that has improved rolling resistance and riding comfort during normal driving without impairing run-flat durability.

2. Description of the Related Art Conventionally, in a pneumatic tire, particularly a run-flat tire, a side rubber reinforcing layer made of a rubber composition alone or a composite of a rubber composition and a fiber is provided to improve the rigidity of the side rubber layer. (For example, see Patent Document 1)
When a pneumatic tire is driven when the internal pressure of the tire (hereinafter referred to as internal pressure) decreases due to puncture or the like, or in a so-called run-flat running state, the deformation of the tire side rubber layer or the bead filler increases and heat generation proceeds. In some cases, the temperature reaches 200 ° C. or higher. In such a state, even in a pneumatic tire provided with a side rubber reinforcing layer, the side rubber reinforcing layer and the bead filler exceed the fracture limit, leading to a tire failure.
As a means of prolonging the time to failure, the rubber composition used for the side rubber reinforcing layer and the bead filler is highly compounded with sulfur to increase the elasticity of the rubber composition, so that the tire side rubber layer and the bead Although there is a technique for suppressing the amount of deformation of the 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 that a rubber composition containing various modified conjugated diene-aromatic vinyl copolymers and a heat resistance improver is used for the side rubber reinforcing layer and the bead filler.
Furthermore, Patent Document 3 proposes that a rubber composition containing a specific conjugated diene polymer and a phenol resin is used for the side rubber reinforcing layer and the bead filler.
These are intended to increase the elastic modulus of the rubber composition used for the side rubber reinforcement layer and the bead filler, and to suppress a decrease in the elastic modulus at high temperatures, greatly improving run-flat durability. However, the rolling resistance during normal running is significantly deteriorated.

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

JP 11-310019 A WO02 / 02356 brochure JP 2004-74960 A

  An object of the present invention is to provide a pneumatic tire with improved rolling resistance and riding comfort during normal driving without impairing run-flat durability under such circumstances.

As a result of intensive studies to develop a pneumatic tire having the above-mentioned preferable properties, the present inventor has found that the dynamic storage elastic modulus (E ′) is not more than a specific value in the physical properties of vulcanized rubber and has a loss. A rubber composition having a tangent tan δ of 28 ° C. to 150 ° C. having a Σ value of a specific value or less is used for a side rubber reinforcing layer and / or a bead filler, and the side rubber layer has a vulcanized rubber property with a dynamic strain of 1%, It has been found that a pneumatic tire using a rubber composition having a loss tangent (tan δ) at 25 ° C. of a certain value or less 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 carcass layer made of one or more carcass plies formed by covering a reinforcing cord with ply coating rubber, a side rubber layer, a side rubber reinforcing layer, and a bead filler, wherein the side rubber reinforcing layer and / or Alternatively, the bead filler contains (A) a rubber component and (B) filler, (A) contains 50 parts by mass or less of (B) filler with respect to 100 parts by mass of the rubber component, and (A) the rubber component is a primary amine. Σ at 28 ° C. to 150 ° C. at 28 ° C. to 150 ° C. including a modified conjugated diene polymer and vulcanized rubber properties having a dynamic storage elastic modulus (E ′) of 10 MPa or less and a loss tangent tan δ at 25 ° C. A rubber composition (a) having a value of 5.0 or less, rubber having a physical property of vulcanized rubber of 1% and a loss tangent (tan δ) at 25 ° C. of 0.15 or less for the side rubber layer A pneumatic tire characterized by using the Narubutsu (b),
[2 ] In the rubber composition, (B) 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. ]
The pneumatic tire according to the above [1 ], which is at least one selected from inorganic fillers represented by:
[3 ] Further, as the ply coating rubber, the rubber composition (c) having a vulcanized rubber physical property having a dynamic elastic modulus (E ′) at a dynamic strain of 1% at 25 ° C. of 6.0 MPa or more is used. [1] Pneumatic tire,
[ 4 ] The pneumatic tire according to the above [ 3 ], wherein the rubber composition (c) has a vulcanized rubber physical property of a dynamic strain of 1% and a loss tangent (tan δ) at 25 ° C. of 0.12 or less.
Is to provide.

According to the present invention,
(1) Dynamic strain of vulcanized rubber by reducing the content of the filler (particularly carbon black) in the rubber composition (a) to be low (50 parts by mass or less with respect to 100 parts by mass of the rubber component) %, By making the dynamic storage elastic modulus (E ′) at 25 ° C. 10 MPa or less, the vehicle can be softened and the riding comfort during normal running can be improved. Further, the heat generation can be reduced by reducing the filling material.
(2) By using a modified conjugated diene polymer (amine-modified, especially primary amine-modified conjugated diene polymer) as a rubber component, it becomes possible to improve the dispersibility of carbon black and suppress heat generation, and the loss tangent tan δ The Σ value at 28 ° C. to 150 ° C. can be set to 5.0 or less, preferably 5.0 to 3.0, and the physical properties of vulcanized rubber in the side rubber are 1% dynamic strain, loss tangent (tan δ) at 25 ° C. By using the rubber composition (b) having a value of 0.15 or less, the heat generation can be further reduced.
(3) Although not essential, as a ply-coating rubber, in terms of physical properties of vulcanized rubber, the dynamic elastic modulus (E ′) at a dynamic strain of 1% at 25 ° C. is 6.0 MPa or more, and the loss tangent (tan δ) is 0. By using the rubber composition (c) which is .12 or less in combination, the tire longitudinal rigidity can be suppressed and further heat generation can be reduced.
(4) As described above, the temperature of the vulcanized rubber increases due to the run-flat running. As the temperature rises, the mechanical properties (breaking stress, breaking elongation, etc.) are significantly reduced, leading to fracture. However, since the rubber composition used in the tire of the present invention can greatly suppress heat generation during run-flat running due to the effects of the above items (1), (2) and (3), the gauge of the reinforcing rubber layer is It can be made thinner and run-flatness can be ensured even with a thin gauge, and fuel efficiency is improved by reducing heat generation and reducing heat generation.
Due to the effects (1) to (4) above, the rubber composition (a), particularly the side rubber reinforcing layer and / or bead filler of a tire, the rubber composition (b) as a side rubber, and optionally a ply coating rubber. By using the rubber composition (c) in combination, it is possible to provide a pneumatic tire with improved rolling resistance and riding comfort during normal running without impairing run-flat durability.

It is a mimetic diagram showing the section of one embodiment of the pneumatic tire of the present 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 according to the present invention is toroidally connected between a pair of beadcos 1, 1 ′ (1 ′ is not shown), and both ends of the bead core 1 are connected to the outside from the inside of the tire. A carcass layer 2 composed of at least one radial carcass ply wound up, a side rubber layer 3 disposed on the outer side in the tire axial direction of the side region of the carcass layer 2, and a crown region of the carcass layer 2 A tread rubber layer 4 disposed on the outer side in the tire radial direction to form a ground contact portion, a belt layer 5 disposed between the tread rubber layer 4 and the crown region of the carcass layer 2 to form a reinforcing belt, An inner liner 6 disposed on the entire inner surface of the carcass layer 2 to form an airtight film, and the carcass extending from one bead core 1 to the other bead core 1 ′. The bead filler 7 disposed between the body layer 2 main body portion and the winding portion wound up on the bead core 1, and the carcass layer 2 extending from the side portion of the bead filler 7 in the side region of the carcass layer to the shoulder region 10. A pneumatic tire including at least one side rubber reinforcing layer 8 having a cross-sectional shape along the tire rotation axis and a substantially crescent shape between the inner liner 6 and the inner liner 6. 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, the side rubber layer 3, and the carcass layer 2 as desired, this pneumatic tire The pneumatic tire of the invention can achieve the above-described effects.

  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 dynamic strain of 1%. By using the rubber composition (b) having a loss tangent (tan δ) at 1% and 25 ° C. of 0.15 or less, the run-flat durability is greatly improved and the rolling resistance and ride comfort during normal driving are improved. An improved pneumatic tire can be provided.

  The pneumatic tire of the present invention is a pneumatic tire comprising a carcass layer comprising one or more carcass plies formed by covering a reinforcing cord with a ply coating rubber, a side rubber layer, a side rubber reinforcing layer, and a bead filler, The side rubber reinforcing layer and / or the bead filler contains (A) a rubber component and (B) filler, and the physical properties of vulcanized rubber have a dynamic storage elastic modulus (E ′) at 25% at a dynamic strain of 1%. Using a rubber composition (a) having a Σ value of 5.0 or less at 28 ° C. to 150 ° C. at a loss tangent tan δ of 10 MPa or less, and vulcanized rubber properties for the side rubber layer, dynamic strain 1% at 25 ° C. A rubber composition (b) having a loss tangent (tan δ) of 0.15 or less is used.

[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 necessary that the vulcanized rubber properties have a dynamic strain of 1% and a Σ value at 28 ° C. to 150 ° C. of a loss tangent tan δ of 5.0 or less. A preferred range is 5.0 to 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 reacted with a protected primary amine compound at the active end of the conjugated diene polymer. A primary amine-modified conjugated diene polymer modified with a protected primary amino group obtained by the above-described method is preferable.

<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 chain having 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, oxolanyl propane oligomers [particularly 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, tin atom, 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 preferred 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 use amount 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-ethylhexanoate) 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, tetrakis (linoleate) titanium, and the like.

  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 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 setting the number average molecular weight of the modified conjugated diene polymer within the above range, the elastic modulus of the vulcanizate is reduced and an 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 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.
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, carbon black and silica are preferable as the filler, 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 side rubber, and in terms of physical properties of the vulcanized rubber, the loss tangent (tan δ) at 1% strain at 25 ° C. needs to be 0.15 or less. 0.10 or less is more preferable, and the lower limit is not particularly limited, but is usually about 0.03. The rubber composition (b) having a loss tangent (tan δ) at 1% strain at 25 ° C. of 0.15 or less is excellent in low heat build-up, so that heat generation during run-flat running is small, side rubber layer heat generation, and tires Heat generation when viewed as a whole can be suppressed. Therefore, by applying a rubber composition (b) having a loss tangent (tan δ) at 1% strain at 25 ° C. of 0.15 or less to the side rubber layer, the temperature increase of the side reinforcing rubber layer during run flat running is suppressed. Thus, the breakage of the side reinforcing rubber layer can be suppressed, and the run flat durability of the tire can be improved.

[Rubber composition (c)]
Next, the rubber composition (c) will be described. The rubber composition (c) is applied to the ply coating rubber as desired, and in terms of physical properties of the vulcanized rubber, the loss tangent (tan δ) at 1% strain at 25 ° C. is preferably 0.12 or less. 0.10 or less is particularly preferable, and the lower limit is not particularly limited, but is usually about 0.05. The rubber composition (c) 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 (c) to the coating rubber of the carcass ply, 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 (c) 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.

  In the pneumatic tire of the present invention, the vulcanization physical property is 1% in dynamic strain, the dynamic storage elastic modulus (E ′) at 25 ° C. is 10 MPa or less, and the Σ value at the loss tangent tan δ of 28 ° C. to 150 ° C. is 5 0.0 or less rubber composition (a) on the side reinforcing rubber layer and / or bead filler, and rubber composition (b) having a loss tangent (tan δ) at 1% strain at 25 ° C. of 0.15 or less as side rubber. If desired, a rubber composition (c) having a loss tangent (tan δ) at 1% strain at 25 ° C. of 0.12 or less is preferably applied to the carcass ply coating rubber. In this case, since the heat generated by the three reinforcing rubber layers, the side rubber layer, and the carcass ply coating rubber during run-flat running is small, heat generation when viewed from the entire tire can be greatly reduced. As a result, the temperature increase of the side reinforcing rubber layer during the run-flat running can be reliably suppressed, and the run-flat durability of the tire can be greatly improved.

  The rubber composition (b) to be applied to the side rubber and the rubber composition (c) to be applied to the carcass ply coating rubber are blended with a low-grade carbon black of FEF grade or less with respect to the rubber component. Things are preferred. Generally, high-grade carbon black is used for the carcass ply coating rubber in order to improve carcass reinforcement, but in the present invention, low-grade carbon of FEF class or lower is used in order to improve low heat generation. 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. Among them, FEF grade carbon black is preferable.

  The rubber components of the rubber compositions (b) and (c) include natural rubber (NR), styrene-butadiene copolymer rubber (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR), and the like. A diene type synthetic rubber is mentioned, and 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, 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), and if it is 100 parts by mass or less, the tensile strength and low heat build-up (low fuel consumption) of the vulcanized rubber deteriorate. 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.

(Physical properties of vulcanized rubber of rubber composition)
The rubber composition (a) according to the present invention is applied to a side reinforcing rubber layer and / or a bead filler, and has a dynamic storage elastic modulus (E ′) at a dynamic strain of 1% and 25 ° C. as a vulcanized rubber property. Is required to be 10 MPa or less. If the dynamic storage elastic modulus (E ′) at 1% dynamic strain and 25 ° C. exceeds 10 MPa, the tire during normal running becomes difficult to bend but the ride comfort is lowered. The dynamic storage elastic modulus (E ′) is preferably 8 MPa or less, and the lower limit thereof is not particularly limited, but is usually about 5.5 MPa.
The dynamic storage elastic modulus (E ′) is a value measured by the following method.
<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 rubber composition (a) 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, the rubber composition (a) is required to have a Σ value [Σ tan δ (28 to 150 ° C.)] at 28 ° C. to 150 ° C. of the loss tangent tan δ of 5.0 or less as a vulcanized rubber property. . 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 (a) at 160 ° C. for 12 minutes, and used as a sample. For this sample, a loss tangent 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 hatched portion is obtained, and the value is Σ tan δ (28 to 150 ° C.).

Furthermore, the rubber composition (b) according to the present invention is applied to the side rubber layer, and as a vulcanized rubber property, the loss tangent (tan δ) at 1% strain at 25 ° C. needs to be 0.15 or less. 0.10 or less is more preferable. The rubber composition (b) having a loss tangent (tan δ) at 1% strain at 25 ° C. of 0.15 or less is excellent in low heat build-up, so that heat generation during run-flat running is small, side rubber layer heat generation, and tires Heat generation when viewed as a whole can be suppressed.
The dynamic storage elastic modulus (E ′) is a value measured by the following method.
<Method of measuring loss tangent (tan δ)>
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 (c) at 160 ° C. for 12 minutes to prepare a sample. A rubber composition was used for the sample under the conditions of a distance between chucks: 10 mm, initial strain: 200 μm, dynamic strain: 1%, frequency: 52 Hz, measurement temperature: 25 ° C. using a spectrometer manufactured by Ueshima Seisakusho Co., Ltd. The loss tangent (tan δ) of the object was measured.

(Preparation of rubber composition, production of pneumatic tire)
The rubber composition (a) 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, vulcanizing after molding, It is used as the side rubber reinforcing layer 8 and / or the bead filler 7 of the pneumatic tire in FIG. The rubber composition (b) is used as the side rubber layer 3.
The tire of the present invention is manufactured by a normal run-flat tire manufacturing method using the rubber composition according to the present invention for the side rubber reinforcing layer 8 and / or the bead filler 7 and the side rubber layer 3. 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 usual 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 >>
The dynamic storage elastic modulus (E ′), loss tangent (tan δ), and Σ value of tan δ at 28 ° C. to 150 ° C. [Σ tan δ (28 to 150 ° C.)] were measured according to the methods described in the specification.
<< 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) under nitrogen. The solution was injected as a cyclohexane solution, and 2.85 mmol of n-butyllithium (BuLi) was added thereto, followed by polymerization in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The reaction conversion of 1,3-butadiene was almost 100%. 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- 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. 1129 mg (3.364 mmol) of bis (trimethylsilyl) aminopropylmethyldiethoxysilane was added and the modification reaction was carried out 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 removed, and the rubber was dried with a ripening 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 Second Amine-Modified Polybutadiene As a modifier, N-methyl-N- (trimethylsilyl) aminopropylmethyldiethoxysilane, which is a secondary amine, is used to carry out a modification reaction based on (2) above. An amine-modified polybutadiene was obtained.
Production Example 3 Production of tertiary amine-modified polybutadiene Using DMAPES: 3-dimethylaminopropyl (diethoxy) methylsilane as a modifier, a modification reaction was performed based on the above (2) to obtain a tertiary amine-modified polybutadiene.

Examples 1 , 2, 7, Reference Examples 1-6 and Comparative Examples 1-9
5 types of rubber compositions (a) of Formulations A to E were prepared for side reinforcing rubbers based on the formulation composition shown in Table 1, and vulcanized physical properties, that is, dynamic strain 1%, storage at 25 ° C. The values of elastic modulus (E ′) and Σtan δ (28 to 150 ° C.) were determined. The measurement results are shown in Table 1.
Next, two types of rubber compositions (b) to F (G) were prepared for side rubbers based on the compounding composition shown in Table 2, and vulcanized physical properties, that is, dynamic strain 1%, storage elasticity at 25 ° C. Values of rate (E ′) and loss tangent (tan δ) were determined. The measurement results are shown in Table 2.
Further, two types of rubber compositions (c) (H) to (I) were prepared for carcass ply coating rubbers based on the blending composition described in Table 3, and the respective vulcanized physical properties, that is, dynamic strain 1%, 25 The values of storage elastic modulus (E ′) and loss tangent (tan δ) at ° C. were determined. The measurement results are shown in Table 3.
In addition, the rubber composition “H” of Table 3 was used for the ply coating rubber of Example 7 , Reference Examples 5 to 6 , and Comparative Examples 1 to 5 , 8, and 9.
Next, these nine kinds of rubber compositions are arranged in the combinations shown in Tables 4 to 1-3, and radial tires for passenger cars having tire sizes of 215 / 45ZR17 are manufactured according to a conventional method. These tires were evaluated for run-flat durability and ride comfort. The results are shown in Tables 4-1. In addition, the maximum thickness of the side rubber reinforcement layer was calculated | required as a reinforcement rubber gauge, and it showed to Table 4 -1-3 similarly.

［注］
１）天然ゴム：ＴＳＲ２０
２）未変性ポリブタジエン：製造例１、（１）ポリブタジエンの製造で得られた物
３）第一アミン変性ポリブタジエン：製造例１で得られたもの
４）第二アミン変性ポリブタジエン：製造例２で得られたもの
５）第三アミン変性ポリブタジエン：製造例３で得られたもの
６）カーボンブラック：ＦＥＦ（Ｎ５５０）、旭カーボン社製「旭＃６０」
７）プロセスオイル：アロマティックオイル、富士興産社製「アロマックス＃３」
８）老化防止剤６Ｃ：Ｎ−（１，３−ジメチルブチル）−Ｎ’−フェニル−ｐ−フェニレンジアミン、大内新興化学工業社製「ノクラック６Ｃ」
９）加硫促進剤ＣＺ：Ｎ−シクロヘキシル−２−ベンゾチアジルスルフェンアミド、大内新興化学工業社製「ノクセラーＣＺ」
１０）加硫促進剤ＴＯＴ：テトラキス（２−エチルへキシル）チウラムジスルフィド、大内新興化学工業社製「ノクセラーＴＯＴ−Ｎ」

[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.

［注］
１１）ＢＲ：ＪＳＲ製「ＢＲ０１」、高シスポリブタジエン
１２）加硫促進剤ＭＢＴＳ：大内新興化学工業社製「ノクセラーＤＭ」

[note]
11) BR: “BR01” manufactured by JSR, high cis polybutadiene 12) Vulcanization accelerator MBTS: “Noxeller DM” manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

［注］
１３）ＳＢＲ：ＪＳＲ社製、２５％スチレン含有スチレン・ブタジエン共重合物
１４）加硫促進剤ＤＭ；ジベンゾチアジルジスルフィド大内新興化学工業社製「ノクセラーＤＭ」

[note]
13) SBR: JSR Co., 25% styrene-containing styrene / butadiene copolymer 14) Vulcanization accelerator DM; Dibenzothiazyl disulfide Ouchi Shinsei Chemical Co., Ltd. “Noxeller DM”

  In the pneumatic tire of the present invention, the rubber composition (a) having a low elastic modulus and low exothermic property is applied to the side reinforcing rubber and / or the bead filler, and the low exothermic rubber composition (b) is applied to the side rubber layer. Thus, it becomes possible to improve rolling resistance and riding comfort during normal running without impairing run-flat durability, and it 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 rubber reinforcing layer 10 shoulder area

Claims (4)

A pneumatic tire comprising a carcass layer comprising one or more carcass plies formed by covering a reinforcing cord with ply coating rubber, a side rubber layer, a side rubber reinforcing layer and a bead filler, the side rubber reinforcing layer and / or the bead filler (A) rubber component and (B) filler, (A) 50 parts by mass or less of (B) filler per 100 parts by mass of rubber component, and (A) the rubber component is a primary amine-modified conjugated diene In the physical properties of the vulcanized rubber, the dynamic storage elastic modulus (E ′) at 25 ° C. is 10 MPa or less and the loss tangent tan δ is 28 in the range of 28 ° C. to 150 ° C. A rubber composition having a rubber composition (a) of 0.0 or less and a physical property of vulcanized rubber in the side rubber layer, a dynamic strain of 1%, and a loss tangent (tan δ) at 25 ° C. of 0.15 or less. A pneumatic tire characterized by using b). In the rubber composition, the filler (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 claim 1, wherein the pneumatic tire is at least one selected from the group consisting of inorganic fillers.   Further, as the ply coating rubber, a rubber composition (c) having a vulcanized rubber physical property having a dynamic elastic modulus (E ′) at a dynamic strain of 1% at 25 ° C. of 6.0 MPa or more is used. The described pneumatic tire. The pneumatic tire according to claim 3 , wherein the rubber composition (c) has a vulcanized rubber physical property of a dynamic strain of 1% and a loss tangent (tan δ) at 25 ° C of 0.12 or less.

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