JP2010042762A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of reducing its weight and improving its rolling resistance without spoiling its run-flat durability and a riding comfort. <P>SOLUTION: The pneumatic tire, which includes a bead filler 7 disposed outside in the radial direction of a bead core 6 and a side-reinforcing layer 5 along the internal surface of a carcass layer at both sides 2, contains at least 55 parts mass of carbon black with respect to 100 parts mass of rubber component, and uses a rubber composition wherein the elastic modulus at 100% elongation elasticity is ≥10 MPa and the sigma value of a tangent loss tan δ at 28-150°C is ≤6.0 in the physical properties of vulcanized rubber. The cord constituting the carcass layer satisfies the following formulas; σ≥-0.01×E+1.2 and σ≥0.02 äwherein σ: heat shrinkage stress (cN/dtex) at 177°C; E: the modulus of elasticity (cN/dtex) under a load of 49N at 25°C}, and contains at least 50 mass% of polyketone fiber which contracts at high temperatures, and extends at room temperatures. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and more particularly to a pneumatic tire capable of reducing tire weight and improving rolling resistance without impairing run-flat durability and riding comfort.

  Conventionally, in a pneumatic tire, particularly a run-flat tire, it is known that a side 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 sidewall portion. (For example, Patent Document 1). When such a run-flat tire is driven with the internal pressure of the tire decreased due to puncture or the like, that is, in a so-called run-flat running state, as the deformation of the sidewall portion of the tire increases, the deformation of the side reinforcing layer also increases. The heat generation proceeds, and in some cases reaches 200 ° C. or higher. If such a state continues, the side reinforcing layer exceeds the fracture limit, and eventually the tire breaks down.

  As a means for earning time until such a failure, there are things that increase the volume of rubber, such as increasing the maximum thickness of the side reinforcing layer and the bead filler to be disposed, but if such a method is taken Undesirable situations such as poor ride comfort, increased weight and increased noise levels occur.

  If the volume of the side reinforcing layer and the bead filler to be disposed is reduced in order to avoid the deterioration of the ride comfort and the weight, for example, the load at the time of run flat cannot be supported. The deformation of the sidewall portion becomes very large, leading to an increase in heat generation of the rubber composition. As a result, there has been a problem that the tire will fail earlier.

  On the other hand, cellulosic fibers such as rayon have higher Young's modulus at room temperature and high temperature than polyesters such as PET, and have high thermal dimensional stability with a heat shrinkage at 177 ° C. of 0.65 to 1.0%. For this reason, the cellulosic fiber has been used as a carcass reinforcing cord of the side reinforcing type run-flat tire.

However, conventional side-reinforced type run-flat tires using cellulosic fiber cords such as rayon as carcass reinforcement cords are not sufficiently high in the elastic modulus of cellulosic fibers, so that the tire is bent during run-flat running. When the tire becomes large due to the run-flat running and the temperature of the tire becomes high, the rigidity of the carcass ply is lowered and the deflection of the tire is further increased. Therefore, the main cause of tire failure at the end of run-flat driving is due to cracking of the side-reinforced rubber layer with a crescent-shaped cross section, and conventional side-reinforced run-flat tires do not always have a durable distance in run-flat driving. It was not satisfactory.
JP 11-310019 A

  Accordingly, an object of the present invention is to eliminate such problems of the prior art, reduce the tire weight without impairing the run-flat durability and riding comfort, and improve the rolling resistance. Is to provide.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above object can be achieved by adopting the following configuration, and have completed the present invention.

That is, the pneumatic tire of the present invention has a carcass layer extending in a toroidal shape between a pair of left and right bead portions including a bead core and a bead filler disposed on the outer side in the radial direction of the bead core. In a pneumatic tire provided with side reinforcing layers arranged on both side portions along the inner surface,
The rubber component contains 55 parts by mass or more of carbon black with respect to 100 parts by mass of the rubber component, and in the physical properties of vulcanized rubber, the elastic modulus at 100% elongation (M100) is 10 MPa or more and the tangent loss tan δ is 28 to 150 ° C. A rubber composition having a Σ value of 6.0 or less at
The cord constituting the carcass layer has the following formulas (I) and (II),
σ ≧ −0.01 × E + 1.2 (I)
σ ≧ 0.02 (II)
(In the above formula, σ is a heat shrinkage stress (cN / dtex) at 177 ° C., and E is an elastic modulus (cN / dtex) at a load of 49 N at 25 ° C.). And at least 50 mass% of the polyketone fiber which has a reversibility which shrink | contracts under high temperature and expand | extends when it returns to room temperature is characterized by the above-mentioned.

  In the present invention, the carbon black is preferably an FEF grade grade, the rubber component preferably contains 30 parts by mass or more of an amine-modified diene rubber, and the side reinforcing layer further comprises the rubber composition. The bead filler is preferably made of the rubber composition.

（式中、Ａは不飽和結合によって重合された不飽和化合物由来の部分であり、各繰り返し単位において同一でも異なっていてもよい）で表される繰り返し単位から実質的になることが好ましく、前記式（ＶＩ）中のＡがエチレン基であることが好ましい。 In the present invention, the fiber cord constituting the carcass layer has the following formulas (III), (IV),
N = n × (0.125 × D / ρ) ^1/2 × 10 ⁻³ (III)
0.34 ≦ N (IV)
(In the above formula, N is the upper twisting coefficient, n is the number of times of upper twisting (times / 10 cm), D is the total decitex number (dtex) of the cord, and ρ is a fiber containing at least 50% by mass of the polyketone fiber. It is preferable that the relationship expressed by specific gravity (g / cm ³ ) is satisfied, and the upper twist coefficient N is represented by the following formula (V)
0.6 ≦ N ≦ 0.9 (V)
It is preferable that the relationship expressed by the following is satisfied, and the number of driven fiber cords constituting the carcass layer is preferably 30 to 60/50 mm, and further, the fiber cords constituting the carcass layer However, it is preferable to consist of a twisted filament bundle having a fineness of 500-2000. In addition, the tensile strength of the polyketone raw yarn contained in the fiber cord is 10 cN / dtex or more, the elastic modulus is 200 cN / dtex or more, and the heat shrinkage rate during the dry heat treatment at 150 ° C. for 30 minutes after the adhesive treatment is It is preferably in the range of 1 to 5%, and the polyketone is represented by the following general formula (VI),

(Wherein A is a portion derived from an unsaturated compound polymerized by an unsaturated bond, and each repeating unit may be the same or different), and preferably consists essentially of the repeating unit, A in formula (VI) is preferably an ethylene group.

  ADVANTAGE OF THE INVENTION According to this invention, the pneumatic tire which improved weight reduction and rolling resistance can be provided, without impairing run-flat durability and riding comfort.

Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partial cross-sectional view of a preferred example of the pneumatic tire of the present invention. The tire shown in FIG. 1 has a pair of left and right bead portions 1 and a pair of sidewall portions 2, and a tread portion 3 connected to both side portions 2, and extends in a toroidal shape between the pair of bead portions 1. A carcass layer composed of one or more carcass plies 4 that reinforce each of these portions 1, 2, and 3, and a pair of crescent-shaped side reinforcing rubber layers 5 disposed inside the carcass ply 4 of the side portion 2.

  In the illustrated tire, a bead filler 7 is disposed on the outer side in the tire radial direction of each of the ring-shaped bead cores 6 embedded in the bead portion 1, and the outer side in the tire radial direction of the tread portion of the carcass ply 4. Further, a belt 8 composed of two belt layers is disposed, and a belt reinforcing layer 9A is disposed so as to cover the entire belt 8 on the outer side in the tire radial direction of the belt 8, and further, the belt reinforcing layer 9A. A pair of belt reinforcing layers 9B are arranged so as to cover only both ends of the belt. Here, the belt layer is usually composed of a rubberized layer of a cord extending in an inclined manner with respect to the tire equatorial plane, preferably a rubberized layer of a steel cord, and the two belt layers constitute the belt layer. The belt 8 is formed by laminating the cords so as to cross each other with the equator plane interposed therebetween. The belt reinforcing layers 9A and 9B are usually made of rubberized layers of cords arranged substantially parallel to the tire circumferential direction.

  The carcass ply 4 in the illustrated example is composed of a single carcass ply formed by coating a plurality of reinforcing cords arranged in parallel with a coating rubber, and the carcass ply 4 is respectively disposed in the bead portion 1. The present invention comprises a main body portion extending in a toroidal shape between a pair of embedded bead cores 6 and a folded portion wound around each bead core 6 radially outward from the inner side to the outer side in the tire width direction. In the pneumatic tire, the number of plies and the structure of the carcass ply 4 are not limited thereto. Furthermore, although the belt 8 in the illustrated example is composed of two belt layers, in the pneumatic tire of the present invention, the number of belt layers constituting the belt 8 is not limited to this. Furthermore, in the pneumatic tire of the present invention, it is not essential to dispose the belt reinforcing layers 9A and 9B, and a belt reinforcing layer having another structure can be disposed.

The pneumatic tire of the present invention contains 55 parts by mass or more of carbon black with respect to 100 parts by mass of a rubber component, and has a vulcanized rubber physical property of an elastic modulus at 100% elongation (M100) of 10 MPa or more and a tangent Using a rubber composition having a Σ value of loss tan δ at 28 to 150 ° C. of 6.0 or less, and the cord constituting the carcass layer are represented by the following formulas (I) and (II):
σ ≧ −0.01 × E + 1.2 (I)
σ ≧ 0.02 (II)
(In the above formula, σ is a heat shrinkage stress (cN / dtex) at 177 ° C., and E is an elastic modulus (cN / dtex) at a load of 49 N at 25 ° C.). In addition, it is important to contain at least 50% by mass of a polyketone fiber having reversibility that shrinks at a high temperature and stretches when returned to room temperature. With the above configuration, run-flat durability can be enhanced without impairing rolling resistance and riding comfort during normal traveling.

  First, the rubber composition according to the present invention will be described. The rubber composition according to the present invention contains 55 parts by mass or more of carbon black with respect to 100 parts by mass of the rubber component, and has a vulcanized rubber property having an elastic modulus at 100% elongation (M100) of 10 MPa or more and The Σ value at 28 to 150 ° C. of the tangent loss tan δ is 6.0 or less. By using the rubber composition according to the present invention for the side reinforcing layer 8 and / or the bead filler 7 of a pneumatic tire, the desired effect of the present invention can be favorably obtained.

  Examples of the rubber component of the rubber composition used in the present invention include natural rubber (NR) and diene synthetic rubber. Examples of the diene-based synthetic rubber include styrene-butadiene copolymer (SBR), polybutadiene (BR), polyisoprene (IR), styrene-isoprene copolymer (SIR), butyl rubber (IIR), halogenated butyl rubber, and ethylene. -Propylene-diene terpolymer (EPDM) and mixed rubbers thereof. Moreover, it is preferable that part or all of the diene-based synthetic rubber is a diene-based modified rubber having a branched structure by using a polyfunctional modifier, for example, a modifier such as tin tetrachloride.

  The rubber composition according to the present invention preferably contains 30 parts by mass or more of an amine-modified diene rubber as a rubber component. More preferably, it is 50 parts by mass or more. By containing 30 parts by mass or more of the amine-modified diene rubber as a rubber component, the resulting rubber composition has a low heat generation, and a pneumatic tire with improved run-flat durability can be obtained.

  The amine-modified diene rubber is preferably one in which a protonic amino group which is an amine functional group and / or an amino group protected with a detachable group is introduced as a functional group for modification in the molecule, and further a silicon atom Those into which a functional group containing is introduced are more preferred. 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 modified functional group may be present at any of the polymerization initiation terminal, the side chain, and the polymerization active terminal of the conjugated diene polymer, but is preferably a protic amino group at the polymerization terminal, more preferably at the same polymerization active terminal. An amino group protected by a group and / or a detachable group and a silicon atom to which a hydrocarbyloxy group and / or hydroxy group is bonded, particularly preferably one or two hydrocarbyloxy groups and / or hydroxy groups are bonded It has a silicon atom.

  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 an N, N-bis (trihydrocarbylsilyl) amino group and an N- (trihydrocarbylsilyl) imino group, preferably a hydrocarbyl group. May be a trialkylsilyl group having 1 to 10 carbon atoms, and particularly preferably a trimethylsilyl group. An example of a primary amino group protected with a detachable group (also referred to as a protected primary amino group) is N, N-bis (trimethylsilyl) amino group, which is protected with a detachable group. Examples of the secondary amino group include N- (trimethylsilyl) imino group. 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, as the primary amine-modified conjugated diene polymer modified with a primary amino group, a protected primary amine compound is reacted with the active terminal 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.

  The conjugated diene copolymer 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 polymerization with the conjugated diene compound include styrene, a-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, divinylbenzene, 4-cyclohexylstyrene, 2 , 4,6-trimethylstyrene and the like. These may be used alone or in combination of two or more. Among these, styrene is particularly preferable. 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 or pseudo-living properties. . As the polymerization reaction having such a living property, an organic alkali metal compound is used as an initiator, and a conjugated diene compound alone or a reaction in which an conjugated diene compound and an aromatic vinyl compound are anionically polymerized in an organic solvent, or an organic solvent. Among them, a conjugated diene compound alone or a reaction in which a conjugated diene compound and an aromatic vinyl compound are coordinated anionic polymerized with a catalyst containing a lanthanum series rare earth element compound can be mentioned. The former is preferable because a conjugated diene moiety having a higher vinyl bond content than the latter can be obtained. Heat resistance can be improved by increasing the amount of vinyl bonds.

  As the organic alkali metal used as the above-mentioned anionic polymerization initiator, 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 is polymerized. A conjugated diene polymer which is an active site is obtained. When a 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- Examples include decyl lithium, phenyl lithium, 2-naphthyl lithium, 2-butylphenyl lithium, 4-phenylbutyl lithium, cyclohexyl lithium, cyclobenthyl lithium, and reaction products of diisopropenylbenzene and butyl lithium. Of these, n-butyllithium is particularly preferable.

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

  As these lithium amide compounds, those prepared in advance from secondary amines and lithium compounds can be used for the polymerization, but they can also be prepared in the polymerization system (in-situ). The amount of the polymerization initiator used is preferably selected in the range of 0.2 to 20 mmol per 100 g of monomer.

  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, a conjugated diene compound or a conjugated diene compound and an aromatic vinyl compound in an organic solvent inert to the reaction, for example, a hydrocarbon solvent such as an aliphatic, alicyclic, or aromatic hydrocarbon compound, A conjugated diene polymer having a target active terminal can be obtained by anionic polymerization in the presence of a randomizer to be used, if desired, using the lithium compound as a polymerization initiator. In addition, when an organolithium 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 rare earth element compound described above. Copolymers of conjugated dienes and aromatic vinyl compounds can also be obtained efficiently.

  The hydrocarbon solvent is preferably one having 3 to 8 carbon atoms, for example, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene, trans- Examples include 2-butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, and ethylbenzene. 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. In addition, when copolymerizing 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 the control of the microstructure of the conjugated diene copolymer, for example, an increase in 1,2 bonds in the butadiene moiety in the butadiene-styrene copolymer, an increase in 3,4 bonds in isoprene, or the like. , A compound having a function 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), 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.

  These randomizers may be used individually by 1 type, and may be used in combination of 2 or more type. The amount used is preferably selected in the range of 0.01 to 1000 molar equivalents per mole of the lithium compound. The temperature in this polymerization reaction is preferably selected in the range of 0 to 150 ° C, more preferably 20 to 130 ° C. The polymerization reaction can be carried out under generated pressure, but it is usually preferred 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 solvent 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. Is performed by an appropriate method such as pressurizing.

  In the present invention, a primary amine-modified conjugated diene polymer is obtained by reacting a protected primary amine as a modifier on the active terminal of the conjugated diene polymer having an active terminal obtained as described above. Can be manufactured. 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 (trimethyl) Yl) aminoethylmethyldiethoxysilane, preferably N, N, -bis (trimethylsilyl) aminopropylmethyldimethoxysilane, N, N, -bis (trimethylsilyl) aminopropylmethyldiethoxysilane, or 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane.

  Further, as modifiers, 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) diethoxysilane 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 and N-trimethylsilyl (4,5-dihydroimidazol-5-yl) propyl (methyl) diethoxysilane; N- (1,3dimethyl) Butylidene) -3- (triethoxysilyl) -1-propanamine, N- (1-methylethylidene) -3- (triethoxysilyl) -1-propanamine, N-ethylidene-3- (triethoxysilyl) -1-propanamine, N- (1-methylpropylide) ) -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-dibutylaminopropyl (diethoxy) methylsilane, 3-dibutylaminopropyl (triethoxy) silane Examples thereof include alkoxysilane compounds having an amino group such as These modifiers may be used alone or in combination of two or more. The modifier may be a partial condensate. Here, the partial condensate means a product in which a part (not all) of the modifier SiOR is bonded to SiOSi 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 not containing an additive such as an anti-aging agent added at the time of production or after 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 for adding the modifier is not particularly limited, and examples thereof include a batch addition method, a division addition method, and a continuous addition method. A batch addition method is 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.

  In the present invention, a condensation accelerator is preferably used in order to accelerate the condensation reaction involving the alkoxysilane compound having a protected primary amino group used as the modifier. As such a condensation accelerator, a compound containing a tertiary amino group or a group 3, 4, 5, 12, 13, 14, or 15 of the periodic table (long period type) is used. An organic compound containing one or more elements belonging to any one of them can be used. Further, as a condensation accelerator, an alkoxide containing at least one metal selected from the group consisting of titanium (Ti), zirconium (Zr), bismuth (Bi), aluminum (Al) and tin (Sn) , Carboxylate, or acetylacetonate complex.

  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 hydrocarboxy 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-butoxy. Titanium, tetra-tert-butoxytitanium, tetra (2-ethylhexyl) titanium, bis (octanediolate) bis (2-ethylhexyl) titanium, tetra (octanediolate) titanium, titanium lactate, titanium dipropoxybis (triethanolamido) Nate), titanium dibutoxybis (triethanolamate), titanium tributoxy systemate, titanium tripropoxy systemate, titanium ethylhex Ludiolate, Titanium tripropoxyacetylacetonate, Titanium dipropoxybis (acetylacetonate), Titanium tripropoxyethylacetoacetate, Titaniumpropoxyacetylacetonatebis (ethylacetoacetate), Titanium tributoxyacetylacetonate, Titanium tributoxybis ( Acetylacetonate), titanium tributoxyethyl acetate, titanium butoxyacetylacetonate bis (ethylacetoacetate), titanium tetrakis (acetylacetonate), titanium diacetylacetonate bis (ethylacetoacetate), bis (2-ethylhexanoate) ) Titanium oxide, bis (laurate) titanium oxide, bis (naphthenate) Nium oxide, bis (stearate) titanium oxide, bis (oleate) titanium oxide, bis (linoleate) titanium oxide, tetrakis (2-ethylhexyl) titanium, tetrakis (laurate) titanium, tetrakis (naphthenate) titanium, tetrakis (stearate) Examples include titanium-containing compounds such as titanium, titanium (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-ethylhexyl) zirconium, tetrakis (laurate) zirconium, tetrakis (naphthenate) zirconium, tetrakis (Stearate) Zirconium, Tetrakis (oleate) Zirconium, Tetra Scan (linoleate) zirconium, and the like can be given.

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

  Of the above-described polymerization accelerators, titanium compounds are preferred, and titanium metal alkoxides, titanium metal carboxylates, or titanium metal acetylacetonate complex salts are particularly preferred. The amount of the condensation accelerator used is preferably such that the number of moles of the compound is 0.1 to 10 as the molar ratio to the total amount of hydrocarbyloxy groups present in the reaction system, and 0.5 to 5 Particularly preferred. By setting the amount used as 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 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 performed in an aqueous solution, and the condensation reaction temperature is preferably 85 to 180 ° C. More preferably. 100-170 degreeC, Most preferably, it is 110-150 degreeC. 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 minutes, preferably about 15 minutes to 5 hours. The pressure of the reaction system during the condensation reaction time is usually 0.01 to 20 MPa, preferably 0.05 to 10 MPa. There is no restriction | limiting in particular about the type in the case of performing a condensation reaction in aqueous solution, You may carry out continuously using apparatuses, such as a batch type reactor or a multistage continuous reactor. Moreover, you may perform this condensation reaction and 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 stage from the stage including the condensation treatment to the solvent removal and the dry polymer.

The amine-modified diene rubber 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, rubber properties such as fracture resistance are not sufficiently obtained, and when it exceeds 150, workability is poor and kneading with a compounding agent is difficult. Moreover, the Mooney viscosity (ML1 _{+ 4} , 130 degreeC) of the unvulcanized rubber composition based on this invention which mix | blended the said amine modified diene rubber becomes like this. Preferably it is 10-150, More preferably, it is 30-100.

  The amine-modified diene rubber 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, a molecular weight distribution (Mw / Mn) of 1 to 3. Is preferable, and 1.1 to 2.7 is more preferable. By setting the molecular weight distribution (Mw / Mn) of the amine-modified diene rubber within the above range, even if the amine-modified diene rubber is blended in the rubber composition, the workability of the rubber composition is not lowered and kneading can be performed. It is easy and the physical properties of the rubber composition can be sufficiently improved.

  Further, the amine-modified diene rubber used in the rubber composition according to the present invention preferably has a number average molecular weight (Mn) of 100,000 to 500,000, more preferably 150,000 to 300,000. . By setting the number average molecular weight of the amine-modified diene rubber within the above range, the rubber composition containing the amine-modified diene rubber is excellent in that the elastic modulus of the vulcanizate is reduced and the increase in hysteresis loss is suppressed to obtain excellent fracture resistance. Kneading workability can be obtained. The amine-modified diene rubber used in the rubber composition according to the present invention may be one type or a combination of two or more types.

  In the rubber composition according to the present invention, the carbon black is required to be 55 parts by mass or more with respect to 100 parts by mass of the rubber component. When the carbon black is less than 55 parts by mass, a sufficient reinforcing effect cannot be exhibited, and in the vulcanized rubber properties of the resulting rubber composition, the elastic modulus at 100% elongation (M100) described later is 10 MPa or more. It may not be possible. On the other hand, if the amount of carbon black is too large, the Σ value at 28 to 150 ° C. of tangent loss tan δ described later may not be 6.0 or less in the vulcanized rubber properties of the resulting rubber composition. Therefore, the preferable amount of carbon black is 55 to 70 parts by mass, and more preferably 60 to 70 parts by mass.

  As carbon black used in the present invention, in order that the vulcanized rubber properties of the obtained rubber composition satisfy the above vulcanized rubber properties, FEF grade, FF grade, HAF grade, ISAF grade and SAF It is preferable to use at least one selected from grade grades, and FEF grade grades are particularly suitable.

  The rubber composition according to the present invention is required to have a vulcanized rubber property having an elastic modulus at 100% elongation (M100) of 10 MPa or more. When the elastic modulus (M100) is less than 10 MPa, the tire is not sufficiently bent and retained during run-flat running, and the run-flat durability of the tire is reduced. Preferred M100 is 10.5 MPa or more, and the upper limit is not particularly limited, but is usually about 13 MPa.

  Further, the Σ value at 28 to 150 ° C. of the tangent loss tan δ is required to be 6.0 or less. When the Σ value of tan δ (28 to 150 ° C.) exceeds 6.0, tire heat generation during run flat running is great, and the run flat running durability of the tire is lowered. The lower limit of the Σ value of tan δ (28 to 150 ° C.) is not particularly limited, but is usually about 5. The Σ values of the elastic modulus at 100% elongation (M100) and tan δ (28 to 150 ° C.) are values measured by the following method.

(Measurement method of elastic modulus at 100% elongation (M100))
An elastic modulus at 100% elongation is measured based on JIS K 6251 for a slab sheet having a thickness of 2 mm obtained by vulcanizing the rubber composition at 160 ° C. for 12 minutes.

(Measurement method of 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. With respect to this sample, a tangent loss tan δ was measured using a spectrometer manufactured by Ueshima Seisakusho Co., Ltd. under measurement conditions of a chuck interval 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. As shown in FIG. 5, the relationship between temperature and tan δ is graphed, the area of the shaded portion is obtained, and the value is set as the Σ value of tan δ (28 to 150 ° C.).

  The rubber composition according to the present invention includes various chemicals usually used in the rubber industry as desired, for example, a vulcanizing agent, a vulcanization accelerator, a process oil, and an antioxidant, as long as the effects of the present invention are not impaired. Further, a scorch inhibitor, zinc white, stearic acid, and the like can be contained. Examples of the vulcanizing agent include sulfur, and the amount thereof used is preferably 0.1 to 10.0 parts by weight, more preferably 1.0 to 5 parts by weight, based on 100 parts by weight of the rubber component. 0.0 part by mass. If the amount is less than 0.1 parts by mass, the fracture strength, wear resistance, and low heat build-up of the vulcanized rubber may be reduced. On the other hand, if it 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. For example, M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), CZ (N-cyclohexyl-2-benzothia). Thiol-based vulcanization accelerators such as thiazoles such as disulfurenamide), guanidines such as DPC (diphenylguanidine), or thiurams such as TOT (tetrakis (2-ethylhexyl) thiuram disulfide). The amount used is preferably 0.1 to 5.0 parts by weight, more preferably 0.2 to 3.0 parts by weight, as a sulfur content, with respect to 100 parts by weight of the 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, and if it is 100 parts by mass or less, the deterioration of the tensile strength and low heat build-up (low fuel consumption) of the vulcanized rubber is suppressed. can do.

  Furthermore, examples of the anti-aging agent 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), a high-temperature condensate of diphenylamine and acetone, and the like. The amount used is preferably 0.1 to 5.0 parts by mass, more preferably 0.3 to 3.0 parts by mass, with respect to 100 parts by mass of the rubber component.

  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 by the above blending, vulcanizing after molding, and air in FIG. It is suitably used for the side reinforcing portion 8 and / or the bead filler 7 of the entering tire.

Then, the fiber cord which comprises the carcass layer of the pneumatic tire of this invention is demonstrated.
The fiber cord according to the present invention includes the following formulas (I) and (II),
σ ≧ −0.01 × E + 1.2 (I)
σ ≧ 0.02 (II)
(In the above formula, σ is a heat shrinkage stress (cN / dtex) at 177 ° C., and E is an elastic modulus (cN / dtex) at a load of 49 N at 25 ° C.). In addition, it is important to contain at least 50% by mass of a polyketone fiber having reversibility that contracts under high temperature and expands when returned to room temperature. The polyketone fiber cord has the same weight as a cellulosic fiber cord such as rayon used in a conventional carcass and does not increase the tire weight, so it is possible to suppress deterioration in tire riding comfort. .

  Since the fiber cord has a large heat shrinkage stress at high temperatures, the tire exhibits high rigidity when the tire is relatively flat at the initial run-time when the tire is run flat. The bending rigidity of the tire can be increased to suppress the bending of the tire, and as a result, the run flat durability of the tire can be improved. On the other hand, the fiber cord has low rigidity when the distortion of the tire in the cord extension direction during normal running is small, and therefore does not raise the vertical spring of the tire during normal running.

  If the cord to be used does not satisfy the formula (I), if a cord having a large heat shrinkage stress σ but a low elastic modulus E is used, the deflection of the tire during the run-flat running cannot be sufficiently suppressed. When using a cord with a high elastic modulus E but a small heat shrinkage stress σ, the vertical spring of the tire during normal driving increases and the tire ride comfort during normal driving deteriorates. To do. Further, when the heat shrinkage stress σ at 177 ° C. of the cord to be used is less than 0.02 cN / dtex, the amount of deflection at the time of run-flat running becomes large and the run-flat durability distance becomes short.

  Here, the fiber cord preferably has a heat shrinkage stress σ at 177 ° C. of 1.5 cN / dtex or less. If the thermal contraction stress σ of the fiber cord at 177 ° C. exceeds 1.5 cN / dtex, the shrinkage force during vulcanization becomes too large, resulting in the disorder of the cord in the tire and the disorder of the rubber placement, resulting in durability. Will worsen and uniformity. The fiber cord preferably has a heat shrinkage stress σ at 177 ° C. of 0.20 cN / dtex or more from the viewpoint of sufficiently suppressing deformation of the tire during run-flat running. From the viewpoint of reliably suppressing deformation, the heat shrinkage stress σ at 177 ° C. is more preferably 0.30 cN / dtex or more, and even more preferably 0.4 cN / dtex. In addition, the effect which suppresses the deformation | transformation of the tire at the time of run flat running is so high that heat contraction stress (sigma) is high. Furthermore, the fiber cord preferably has an elastic modulus E at a load of 49 N at 25 ° C. of 30 cN / dtex or more from the viewpoint of sufficiently suppressing deformation of the tire during run flat running. From the viewpoint of reliably suppressing the deformation of the material, it is more preferable that the elastic modulus E at a load of 49 N is 80 cN / dtex or more. Furthermore, the fiber cord preferably has an elastic modulus E at a load of 49 N at 25 ° C. of 170 cN / dtex or less from the viewpoint of sufficiently ensuring fatigue resistance, and from the viewpoint of improving fatigue resistance. More preferably, the elastic modulus E at a load of 49 N is 150 cN / dtex or less.

  The fiber cord needs to contain at least 50% by mass of a reversible polyketone fiber that shrinks at a high temperature and expands when returned to room temperature. In this case, the rigidity increases as the polyketone fiber cord in the carcass ply contracts at high temperatures, that is, during run-flat travel, so that the side wall of the tire can be prevented from bending, and at low temperatures, that is, normal travel. Occasionally, the polyketone fiber cord in the carcass ply is stretched and the rigidity is lowered, and the longitudinal spring of the tire is lowered, so that deterioration of the riding comfort during normal running of the tire can be suppressed. Further, by using a reversible polyketone fiber cord having a difference in heat shrinkage stress between 20 ° C. and 177 ° C. of 0.20 cN / dtex or more, preferably 0.25 cN / dtex or more, during normal running and run flat running Both effects can be achieved.

In the present invention, the cord constituting the carcass has the following formulas (III), (IV),
N = n × (0.125 × D / ρ) ^1/2 × 10 ⁻³ (III)
0.34 ≦ N (IV)
(In the above formula, n is the number of times twisted (times / 10 cm), D is the total decitex of the cord, and ρ is the specific gravity (g / cm ³ ) of the fiber containing at least 50% by mass of the polyketone fiber) It is preferable to satisfy the relationship represented by these. When N is less than 0.34, the fatigue property is remarkably lowered and the durability is insufficient. More preferably, the following formula (V),
0.6 ≦ N ≦ 0.9 (V)
Satisfies the relationship expressed by

  In the carcass ply of the pneumatic tire of the present invention, the number of driven polyketone fiber cords is preferably in the range of 30 to 60 (lines / 50 mm). When the number of driven polyketone fiber cords in the carcass ply is less than 30 (lines / 50 mm), the carcass strength is insufficient and the durability is insufficient. In addition, even if the number of driving exceeds 60 (pieces / 50 mm), there is no particular limitation as long as driving can be performed.

  The polyketone fiber cord used for the carcass ply is preferably made of a polyketone having a fineness of 500 to 2000 dtex, and more preferably, two or three filament bundles made of this polyketone are twisted together. For example, it is possible to obtain a twisted cord having a double twisted structure by applying a lower twist to a filament bundle made of the above polyketone, then combining a plurality of them and applying an upper twist in the opposite direction. If the fineness of the filament bundle used for the polyketone fiber cord is less than 500 dtex, both the elastic modulus and the heat shrinkage stress are insufficient, and if it exceeds 2000 dtex, the cord diameter becomes thick and the driving cannot be made dense. In addition, even if the number of filament bundles made of polyketone is one or four or more, there is no particular limitation as long as the relationship of the above formulas (III) and (IV) can be satisfied.

  The polyketone fiber yarn contained in the fiber cord has a tensile strength of 10 cN / dtex or more, an elastic modulus of 200 cN / dtex or more, and 150 ° C. for 30 minutes after the adhesive treatment (Dip treatment) It is preferable that the heat shrinkage ratio is in the range of 1 to 5%. The tensile strength of the polyketone fiber raw yarn is more preferably 15 cN / dtex or more. As the tensile strength is higher, it can be used in fields where strength is required, and the weight of the fibers used can be kept low. The tensile elastic modulus is more preferably 300 cN / dtex or more. The higher the tensile elastic modulus, the smaller the dimensional change under the same load, and the more excellent the shape stability. Furthermore, as a dip-treated cord, when the heat shrinkage rate during dry heat treatment at 150 ° C. for 30 minutes is less than 1%, the assembling efficiency due to heating at the time of tire production is significantly reduced, and the strength as a tire is insufficient. Become. On the other hand, if the thermal shrinkage rate during dry heat treatment at 150 ° C. for 30 minutes exceeds 5%, the cord is significantly shrunk by heating at the time of manufacturing the tire, so that the finished tire shape may be deteriorated.

で表される繰り返し単位から実質的になるポリケトンが好ましい。また、該ポリケトンの中でも、繰り返し単位の９７モル％以上が１−オキソトリメチレン［−ＣＨ_２−ＣＨ_２−ＣＯ−］であるポリケトンが好ましく、９９モル％以上が１−オキソトリメチレンであるポリケトンが更に好ましく、１００モル％が１−オキソトリメチレンであるポリケトンが最も好ましい。 The polyketone constituting the fiber cord is represented by the following formula (VI),

A polyketone substantially consisting of repeating units represented by Among the polyketones, a polyketone in which 97 mol% or more of repeating units is 1-oxotrimethylene [—CH ₂ —CH ₂ —CO—] is preferable, and polyketone in which 99 mol% or more is 1-oxo trimethylene. Is more preferable, and a polyketone in which 100 mol% is 1-oxotrimethylene is most preferable.

  The polyketone as the raw material of the polyketone fiber cord may be partially bonded with ketone groups and with unsaturated compounds. However, the unsaturated compound-derived portions and ketone groups are alternately arranged. Is preferably 90% by mass or more, more preferably 97% by mass or more, and most preferably 100% by mass.

  In the above formula (VI), the unsaturated compound forming A is most preferably ethylene, but propylene, butene, pentene, cyclopentene, hexene, cyclohexene, heptene, octene, nonene, decene, dodecene, styrene, acetylene. , Unsaturated hydrocarbons other than ethylene, such as allene, methyl acrylate, methyl methacrylate, vinyl acetate, acrylamide, hydroxyethyl methacrylate, undecenoic acid, undecenol, 6-chlorohexene, N-vinylpyrrolidone, diethyl ester of sulphonylphosphonic acid , A compound containing an unsaturated bond, such as sodium styrenesulfonate, sodium allylsulfonate, vinylpyrrolidone and vinyl chloride.

（式中、ｔ及びＴは、純度９８％以上のヘキサフルオロイソプロパノール及び該ヘキサフルオロイソプロパノールに溶解したポリケトンの希釈溶液の２５℃での粘度管の流過時間であり；Ｃは、上記希釈溶液１００ｍＬ中の溶質の質量（ｇ）である）で定義される極限粘度［η］が１〜２０ｄＬ／ｇの範囲にあることが好ましく、２〜１０ｄＬ／ｇの範囲にあることが更に好ましく、３〜８の範囲にあることがより一層好ましい。極限粘度が１ｄＬ／ｇ未満では、分子量が小さ過ぎて、高強度のポリケトン繊維コードを得ることが難しくなる上、紡糸時、乾燥時及び延伸時に毛羽や糸切れ等の工程上のトラブルが多発することがあり、一方、極限粘度が２０ｄＬ／ｇを超えると、ポリマーの合成に時間及びコストがかかる上、ポリマーを均一に溶解させることが難しくなり、紡糸性及び物性に悪影響が出ることがある。 Furthermore, as a polymerization degree of the said polyketone, following formula (VII),

(Wherein t and T are the flow time of a viscosity tube at 25 ° C. of a diluted solution of hexafluoroisopropanol having a purity of 98% or more and a polyketone dissolved in the hexafluoroisopropanol; The intrinsic viscosity [η] defined by the mass of the solute in (g) is preferably in the range of 1 to 20 dL / g, more preferably in the range of 2 to 10 dL / g, More preferably, it is in the range of 8. If the intrinsic viscosity is less than 1 dL / g, the molecular weight is too small to obtain a high-strength polyketone fiber cord, and troubles such as fluff and yarn breakage occur frequently during spinning, drying and stretching. On the other hand, if the intrinsic viscosity exceeds 20 dL / g, it takes time and cost to synthesize the polymer, and it becomes difficult to uniformly dissolve the polymer, which may adversely affect the spinnability and physical properties.

  As the method for fiberizing the polyketone, (1) after spinning an unstretched yarn, performing multi-stage heat stretching, and stretching at a specific temperature and magnification in the final stretching step of the multi-stage heat stretching, (2 ) A method in which after the undrawn yarn is spun, hot drawing is performed, and the fiber after completion of the hot drawing is rapidly cooled with high tension applied. A desired filament suitable for production of the polyketone fiber cord can be obtained by fiberizing the polyketone by the method (1) or (2).

  Here, the spinning method of the unstretched yarn of the polyketone is not particularly limited, and a conventionally known method can be employed. Specifically, JP-A-2-112413, JP-A-4-228613, Wet spinning method using an organic solvent such as hexafluoroisopropanol and m-cresol as described in JP-A-4-505344, WO99 / 18143, WO00 / 09611, JP2001-164422 No., JP-A No. 2004-218189, JP-A No. 2004-285221, and the wet spinning method using an aqueous solution of zinc salt, calcium salt, thiocyanate, iron salt, etc., among these, A wet spinning method using an aqueous solution of is preferred.

  For example, in the wet spinning method using an organic solvent, a polyketone polymer is dissolved in hexafluoroisopropanol, m-cresol, or the like at a concentration of 0.25 to 20% by mass, extruded from a spinning nozzle to be fiberized, and then toluene, ethanol, isopropanol , N-hexane, isooctane, acetone, methyl ethyl ketone, etc., the solvent can be removed and washed in a non-solvent bath to obtain a polyketone undrawn yarn.

  On the other hand, in the wet spinning method using an aqueous solution, for example, a polyketone polymer is dissolved in an aqueous solution of zinc salt, calcium salt, thiocyanate, iron salt or the like at a concentration of 2 to 30% by mass, and a spinning nozzle is formed at 50 to 130 ° C. Then, it is extruded into a coagulation bath and subjected to gel spinning, followed by desalting and drying to obtain an undrawn polyketone yarn. Here, in the aqueous solution in which the polyketone polymer is dissolved, it is preferable to use a mixture of zinc halide and a halogenated alkali metal salt or a halogenated alkaline earth metal salt. An organic solvent such as an aqueous solution, acetone, or methanol can be used.

  Further, as a drawing method of the obtained undrawn yarn, a hot drawing method in which the undrawn yarn is heated and drawn to a temperature higher than the glass transition temperature of the undrawn yarn is preferable. The method (2) may be carried out in one stage, but it is preferably carried out in multiple stages. There is no restriction | limiting in particular as this heat drawing method, For example, the method etc. which run a thread | yarn on a heating roll or a heating plate are employable. Here, the heat stretching temperature is preferably in the range of 110 ° C. to (the melting point of the polyketone), and the total stretching ratio is preferably 10 times or more.

  When polyketone fiberization is carried out by the method of (1) above, the temperature in the final stretching step of the multistage hot stretching is in the range of 110 ° C. to (the stretching temperature of the stretching step one step before the final stretching step). Moreover, the draw ratio in the final drawing step of multistage hot drawing is preferably in the range of 1.01 to 1.5 times. On the other hand, when polyketone fiberization is carried out by the method of (2) above, the tension applied to the fiber after completion of the hot drawing is preferably in the range of 0.5 to 4 cN / dtex, and the cooling rate in rapid cooling is 30 The cooling end temperature in the rapid cooling is preferably 50 ° C. or less. Here, the method for rapidly cooling the heat-stretched polyketone fiber is not particularly limited, and a conventionally known method can be adopted. Specifically, a cooling method using a roll is preferable. In addition, since the polyketone fiber obtained in this way has a large residual elastic strain, it is usually preferable to perform relaxation heat treatment so that the fiber length is shorter than the fiber length after hot drawing. Here, the temperature of the relaxation heat treatment is preferably in the range of 50 to 100 ° C., and the relaxation ratio is preferably in the range of 0.980 to 0.999 times.

  The cord / rubber composite used for the carcass ply can be obtained by coating the polyketone fiber cord obtained as described above with a coating rubber. Here, there is no restriction | limiting in particular as coating rubber of a polyketone fiber cord, The coating rubber used for the conventional carcass ply can be used. Prior to coating the polyketone fiber cord with the coating rubber, the polyketone fiber cord may be subjected to an adhesive treatment to improve the adhesion to the coating rubber.

  The pneumatic tire of the present invention can be manufactured by applying a cord / rubber composite formed by coating the above-mentioned polyketone fiber cord with a coating rubber to the carcass ply of the carcass 4 and using a conventional method. In the pneumatic tire of the present invention, as the gas filled in the tire, normal or air with a changed oxygen partial pressure, or an inert gas such as nitrogen can be used.

Hereinafter, the present invention will be specifically described based on examples.
Eight types of rubber compositions having the compounding compositions A to F shown in Table 1 below were prepared, and physical properties of each vulcanized rubber, that is, Σ values at 28 to 150 ° C. of M100 and tan δ were determined. Next, the cords / rubber composites L and M are manufactured by arranging the fiber cords of the material, structure, twist coefficient and heat shrinkage stress shown in Table 2 below in parallel by the number of drivings shown in Table 2 and covering with coating rubber. did. The primary amine-modified polybutadiene was prepared by the following procedure.

<Production of primary amine-modified polybutadiene>
A nitrogen-substituted 5 L autoclave was injected under nitrogen as a solution of 1.4 kg of cyclohexane, 250 g of 1,3-butadiene, 2,2-ditetrahydrofurylpropane (0.0285 mmol) in cyclohexane, and 2.85 mmol of n- After adding butyl lithium (Bu-Li), polymerization was performed 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 polymerization 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.

  The obtained polymer solution was kept at a temperature of 50 ° C. without deactivating the polymerization catalyst, and 1129 mg (3.364 mmol) of N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane in which the primary amino group was protected. And the denaturation reaction was carried out for 15 minutes. Finally, 2,6-di-tert-butyl-p-cresol was added to the polymerization solution after the reaction. Next, the primary amino group that was desolvated and protected by steam stripping was removed, and the rubber was dried by a hot 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. The microstructure is analyzed by infrared method (Morello method), and Mn, Mw, and Mw / Mn are measured by GPC (manufactured by Tosoh Corporation: HLC-8020) using a refractometer as a detector, and monodisperse It was shown in terms of polystyrene using polystyrene as a standard. The column is GMHXL (manufactured by Tosoh Corporation) and the eluent is tetrahydrofuran.

<Measurement of primary amino group content>
First, after dissolving the polymer in toluene, the amino group-containing compound not bound to the polymer was separated from the rubber by precipitation in a large amount of methanol, and then dried. Using this treated polymer as a sample, the total amino group content was quantified by the “total amine value test method” described in JIS K 7237. Subsequently, secondary amino groups and tertiary amino groups were quantified by the “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 is divided by the polymer mass used in the analysis, thereby binding to the polymer primary. The amino group content (mmol / kg) was determined.

  A run flat tire of the type shown in FIG. 1 was produced using the rubber compositions A to F and the cord / rubber composites L and M produced previously. About each obtained test tire, run-flat durability, riding comfort, and rolling resistance were evaluated. The evaluation method is as follows. The maximum thickness of the side reinforcing layer was determined as a reinforcing rubber gauge and is shown in Tables 3 and 4.

<Runflat durability>
Each test tire (passenger car radial tire of tire size 215 / 45R17) is assembled with rims at normal pressure, filled with 230 kPa of internal pressure, allowed to stand at room temperature of 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 kgf), 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 expressed by the following equation. 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)

<Ride comfort>
Each test tire was mounted on a passenger car, a feeling test of ride comfort was conducted by two specialized drivers, a score of 1-10 was given, and the average was obtained. The larger the value, the better the ride comfort.

<Rolling resistance>
Rotate the drum while contacting the tire on a steel drum with a diameter of 2 m, and after increasing the speed to a constant speed, turn off the drum drive switch, rotate the drum freely, and determine the rolling resistance from the degree of deceleration. The rolling resistance was set to 100 and indicated as an index. The smaller the index value, the smaller the rolling resistance and the better.

※１ 天然ゴム：ＴＳＲ２０
※２ 未変性ポリブタジエン：ＪＳＲ社製ＢＲ０１
※３ １級アミン変性ポリブタジエン：自社製造品
※４ ＦＥＦ（Ｎ５５０）、旭カーボン社製：旭＃６０

* 1 Natural rubber: TSR20
* 2 Unmodified polybutadiene: BR01 manufactured by JSR
* 3 Primary amine-modified polybutadiene: In-house manufactured * 4 FEF (N550), Asahi Carbon Co., Ltd .: Asahi # 60

※５ ２５℃、４９Ｎ荷重
※６ １７７℃加熱時
※７ ポリケトン

* 5 25 ° C, 49N load * 6 When heated at 177 ° C * 7 Polyketone

  From Tables 3 and 4 above, it was confirmed that the pneumatic tire according to the present invention can reduce weight and improve rolling resistance without impairing run-flat durability and riding comfort.

It is a half sectional view of the pneumatic tire of the present invention. It is a graph for calculating | requiring tan (delta) (28-150 degreeC) in the vulcanization | cure property of a rubber composition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bead part 2 Side wall part 3 Tread part 4 Carcass ply 5 Reinforcement rubber layer 6 Bead core 7 Bead filler 8 Belt 9A, 9B Belt reinforcement layer

Claims (12)

A carcass layer extending in a toroidal shape between a pair of left and right bead portions including a bead core and a bead filler disposed radially outside the bead core is disposed on both side portions along the inner surface of the carcass layer. In pneumatic tires with side reinforcement layers
The rubber component contains 55 parts by mass or more of carbon black with respect to 100 parts by mass thereof, and in the vulcanized rubber properties, the elastic modulus at 100% elongation (M100) is 10 MPa or more and the tangent loss tan δ at 28 to 150 ° C. Using a rubber composition having a value of 6.0 or less,
The cord constituting the carcass layer has the following formulas (I) and (II),
σ ≧ −0.01 × E + 1.2 (I)
σ ≧ 0.02 (II)
(In the above formula, σ is a heat shrinkage stress (cN / dtex) at 177 ° C., and E is an elastic modulus (cN / dtex) at a load of 49 N at 25 ° C.). A pneumatic tire comprising at least 50% by mass of a reversible polyketone fiber that shrinks at a high temperature and expands when returned to room temperature.   The pneumatic tire according to claim 1, wherein the carbon black is FEF grade.   The pneumatic tire according to claim 1 or 2, wherein the rubber component contains 30 parts by mass or more of an amine-modified diene rubber.   The pneumatic tire according to claim 1, wherein the side reinforcing layer is made of the rubber composition.   The pneumatic tire according to claim 1, wherein the bead filler is made of the rubber composition. The fiber cord constituting the carcass layer has the following formulas (III), (IV),
N = n × (0.125 × D / ρ) ^1/2 × 10 ⁻³ (III)
0.34 ≦ N (IV)
(In the above formula, N is the upper twisting coefficient, n is the number of times of upper twisting (times / 10 cm), D is the total decitex number (dtex) of the cord, and ρ is a fiber containing at least 50% by mass of the polyketone fiber. The pneumatic tire according to any one of claims 1 to 5, which satisfies a relationship represented by specific gravity (g / cm ³ ). The upper twist coefficient N is the following formula (V),
0.6 ≦ N ≦ 0.9 (V)
The pneumatic tire according to claim 6, satisfying a relationship represented by:   The pneumatic tire according to any one of claims 1 to 7, wherein a number of fiber cords constituting the carcass layer is 30 to 60/50 mm.   The pneumatic tire according to any one of claims 1 to 8, wherein the fiber cord constituting the carcass layer is formed by twisting a filament bundle having a fineness of 500 to 2000.   The tensile strength of the polyketone fiber base yarn contained in the fiber cord is 10 cN / dtex or more, the elastic modulus is 200 cN / dtex or more, and the heat shrinkage rate at the time of dry heat treatment at 150 ° C. for 30 minutes after the adhesive treatment is 1 The pneumatic tire according to any one of claims 1 to 9, which is in a range of -5%. The polyketone is represented by the following general formula (VI):

(Wherein A is a portion derived from an unsaturated compound polymerized by an unsaturated bond, and may be the same or different in each repeating unit). The pneumatic tire according to any one of the above.   The pneumatic tire according to claim 11, wherein A in the formula (VI) is an ethylene group.

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