JP2018111780A - Rubber composition for tire, and pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for a tire which is excellent in on-ice performance, wet grip performance, low heat build-up properties, and wear resistance when formed into a tire, and to provide a pneumatic tire using the rubber composition for a tire.SOLUTION: The rubber composition for a tire contains a diene rubber, silica, and a cured product. The content of the silica is 20-100 pts.mass based on 100 pts.mass of the diene rubber, and the content of the cured product is 0.3-30 pts.mass based on 100 pts.mass of the diene rubber. The diene rubber contains a natural rubber and a specific modified conjugated diene polymer. The content of the natural rubber in the diene rubber is 30-90 mass%, and the content of the modified conjugated diene polymer in the diene rubber is 10-70 mass%. The cured product is obtained by curing a crosslinkable oligomer or polymer incompatible with the diene rubber and has a JIS A hardness of 3-45.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tire rubber composition and a pneumatic tire.

  Conventionally, as a rubber composition used for a tire tread portion of a studless tire, a composition containing natural rubber, butadiene rubber, and a cured product of a crosslinkable polymer is known (Example of Patent Document 1). Patent Document 1 describes that by using the above composition, the performance on ice and the wear resistance of a tire can be improved.

Japanese Patent Laying-Open No. 2015-67636

On the other hand, with improvement in the required safety level, further improvement in performance on ice, wet grip performance and wear resistance is required for studless tires. In addition, low heat generation is also required due to environmental problems and resource problems.
Under these circumstances, the present inventors prepared a rubber composition for a tire with reference to the example of Patent Document 1 and evaluated the performance when made into a tire. As for the low heat build-up, it has become clear that further improvement is desirable in view of demands that will increase further in the future.

  Therefore, in view of the above circumstances, the present invention uses a tire rubber composition that is excellent in performance on ice, wet grip performance, low heat build-up and wear resistance when made into a tire, and the tire rubber composition. An object is to provide a pneumatic tire.

As a result of earnestly examining the above problems, the present inventors blended a diene rubber containing a specific modified conjugated diene polymer, silica, and a specific cured product at a predetermined ratio. Has been found to be able to be solved, and the present invention has been achieved.
That is, the present inventors have found that the above problem can be solved by the following configuration.

(1) containing a diene rubber, silica, and a cured product,
The content of the silica is 20 to 100 parts by mass with respect to 100 parts by mass of the diene rubber, and the content of the cured product is 0.3 to 30 parts by mass with respect to 100 parts by mass of the diene rubber. ,
The diene rubber contains natural rubber and a modified conjugated diene polymer, the content of the natural rubber in the diene rubber is 30 to 90% by mass, and the modified conjugate in the diene rubber. The diene polymer content is 10 to 70% by mass,
The modified conjugated diene polymer is obtained by modifying the active terminal of a conjugated diene polymer having a cis-1,4-bond content of 75 mol% or more with at least a hydrocarbyloxysilane compound. And
A rubber composition for tires, wherein the cured product is a cured product obtained by curing a crosslinkable oligomer or polymer that is incompatible with the diene rubber, and the cured product has a JIS A hardness of 3 to 45.
(2) The rubber composition for tires according to (1), wherein the cured product is a particulate material having an average particle diameter of 5 to 250 μm.
(3) The rubber composition for tires according to (1) or (2) above, wherein the crosslinkable oligomer or polymer is a polyether-based or siloxane-based polymer or copolymer and has a silane functional group. object.
(4) Furthermore, it contains an aromatic modified terpene resin having a softening point of 60 to 150 ° C. and a thermally expandable microcapsule,
The content of the aromatic-modified terpene resin is 2 to 20 parts by mass with respect to 100 parts by mass of the diene rubber, and the content of the thermally expandable microcapsule is 0.00 with respect to 100 parts by mass of the diene rubber. The tire rubber composition according to any one of (1) to (3), which is 5 to 20 parts by mass.
(5) A pneumatic tire using the tire rubber composition according to any one of (1) to (4) above.

  As shown below, according to the present invention, a tire rubber composition excellent in performance on ice, wet grip performance, low heat build-up and wear resistance when made into a tire, and the tire rubber composition were used. A pneumatic tire can be provided.

It is a partial section schematic diagram of the tire showing an example of the embodiment of the pneumatic tire of the present invention.

Below, the rubber composition for tires of this invention and the pneumatic tire using the said rubber composition for tires are demonstrated.
In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Rubber composition for tire]
The rubber composition for tires of the present invention (hereinafter also referred to as “the composition of the present invention”) contains a diene rubber, silica, and a cured product, and the silica content is 100 masses of the diene rubber. It is 20-100 mass parts with respect to a part, and content of the said hardened | cured material is 0.3-30 mass parts with respect to 100 mass parts of said diene rubbers.
Here, the diene rubber includes a natural rubber and a modified conjugated diene polymer, the content of the natural rubber in the diene rubber is 30 to 90% by mass, and the diene rubber in the diene rubber. The content of the modified conjugated diene polymer is 10 to 70% by mass.
Further, the modified conjugated diene polymer is a modified conjugated diene polymer obtained by modifying the active terminal of a conjugated diene polymer having a cis-1,4-bond content of 75 mol% or more with at least a hydrocarbyloxysilane compound. It is a polymer.
Moreover, the said hardened | cured material is a hardened | cured material which hardened the crosslinkable oligomer or polymer which is incompatible with the said diene rubber, and the JIS A hardness of the said hardened | cured material is 3-45.

  Since the composition of this invention takes such a structure, it is thought that a desired effect is acquired. The reason is not clear, but it is presumed that it is as follows.

As described above, the composition of the present invention contains a diene rubber containing natural rubber and a specific modified conjugated diene polymer, silica, and a specific cured product. From the study by the present inventors, the above-mentioned specific cured product has the effect of improving the performance on ice, but it tends to aggregate, and the tendency becomes stronger especially when the content of silica becomes high, and the low heat buildup and wear resistance are increased. It is known that it will decline.
On the other hand, as described above, since the composition of the present invention contains a specific modified conjugated diene polymer, the modified terminal of the specific modified conjugated diene polymer interacts with the cured product to cause aggregation. It is thought to suppress.
As a result, the tire using the composition of the present invention is presumed to exhibit excellent low heat buildup and wear resistance in addition to excellent on-ice performance and wet grip performance.

  Hereinafter, each component contained in the composition of this invention is explained in full detail.

[Diene rubber]
The diene rubber contained in the composition of the present invention includes natural rubber and a modified conjugated diene polymer.
Here, the content of the natural rubber in the diene rubber is 30 to 90% by mass. Especially, it is preferable that it is 40-70 mass% from the reason for which the effect of this invention is more excellent.
The content of the modified conjugated diene polymer in the diene rubber is 10 to 70% by mass. Especially, it is preferable that it is 30-60 mass% from the reason for which the effect of this invention is more excellent.

<Modified conjugated diene polymer>
The modified conjugated diene polymer contained in the diene rubber is an active terminal of a conjugated diene polymer having a cis-1,4-bond content (cis-1,4-bond content) of 75 mol% or more. Is a modified conjugated diene polymer obtained by modifying at least a hydrocarbyloxysilane compound. From the reason that the effect of the present invention is more excellent, the cis-1,4-bond content is preferably 80 mol% or more, more preferably 90 mol% or more, and 95 mol% or more. Further preferred. The upper limit of the cis-1,4-bond content is not particularly limited and is 100 mol%.
In the present specification, the cis-1,4-bond content of the conjugated diene polymer refers to the cis-1,4-bonded conjugated diene unit with respect to all the conjugated diene units of the conjugated diene polymer. Percentage (mol%).

The trans-1,4-bond content (trans-1,4-bond content) in the conjugated diene polymer is 25 mol% or less because the effect of the present invention is more excellent. Is preferably 20 mol% or less, more preferably 10 mol% or less, and particularly preferably 5 mol% or less. The lower limit of the trans-1,4-bond content is not particularly limited and is 0%.
In the present specification, the trans-1,4-bond content of the conjugated diene polymer refers to the trans-1,4-bonded conjugated diene unit relative to the total conjugated diene units of the conjugated diene polymer. Percentage (mol%).

Further, the vinyl bond content (vinyl bond content) in the conjugated diene polymer is preferably 25 mol% or less, and preferably 10 mol% or less, because the effect of the present invention is more excellent. More preferably, it is 5 mol% or less, more preferably 1 mol% or less. The lower limit of the vinyl bond content is not particularly limited and is 0%.
In the present specification, the vinyl bond content of the conjugated diene polymer refers to the ratio (mol%) of the conjugated diene unit of vinyl bond to the total conjugated diene unit of the conjugated diene polymer.

(Intermediate)
A conjugated diene polymer having an active terminal with a cis-1,4-bond content of 75 mol% or more used as an intermediate of the modified conjugated diene polymer (intermediate polymer) is a conjugated diene monomer alone, Or it can manufacture by polymerizing by methods, such as a solution polymerization method, a gaseous-phase polymerization method, a bulk polymerization method, Preferably a solution polymerization method using the following polymerization catalyst with another monomer. The polymerization mode may be either a batch type or a continuous type.

Examples of the raw material monomer conjugated diene compound include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, and the like. . These may be used alone or in combination of two or more, and among these, 1,3-butadiene is particularly preferable.
Further, a small amount of other hydrocarbon monomers may coexist in these conjugated diene compounds, but the conjugated diene compound is preferably 80 mol% or more of the total monomers.

The polymerization catalyst is preferably a combination of at least one compound selected from the following (x) component, (y) component, and (z) component.
[(X) component]
The rare earth compound selected from the following (x1) to (x4) may be used as it is as an inert organic solvent solution or may be supported on an inert solid.
(X1) a rare earth compound having an oxidation number of 3, a carboxylic acid group having 2 to 30 carbon atoms, an alkoxy group having 2 to 30 carbon atoms, an aryloxy group having 6 to 30 carbon atoms, and 1,3-carbon having 5 to 30 carbon atoms One having a total of three ligands freely selected from dicarbonyl-containing hydrocarbon groups, or a Lewis base compound (in particular, free carboxylic acid, free alcohol, 1,3-diketone, cyclic ether, linear chain) Complex ethers, trihydrocarbyl phosphines, trihydrocarbyl phosphites, etc.). Specific examples include neodymium tri-2-ethylhexanoate, a complex compound thereof with acetylacetone, neodymium trineodecanoate, a complex compound thereof with acetylacetone, neodymium tri-n-butoxide, and the like.

(X2) A complex compound of a rare earth trihalide and a Lewis base. For example, there is a THF complex of neodymium trichloride.
(X3) An organic rare earth compound having an oxidation number of 3 in which at least one (substituted) allyl group is directly bonded to a rare earth atom. For example, there is a salt of tetraallyl neodymium and lithium.
(X4) an organic rare earth compound having an oxidation number of 2 or 3 in which at least one (substituted) cyclopentadienyl group is directly bonded to a rare earth atom, or an ion composed of this compound and trialkylaluminum or a non-coordinating anion and a counter cation It is a reaction product with a functional compound. An example is dimethylaluminum (μ-dimethyl) bis (pentamethylcyclopentadienyl) samarium.

As the rare earth element of the rare earth compound, lanthanum, neodymium, praseodymium, samarium and gadolinium are preferable, and among these, lanthanum, neodymium and samarium are more preferable.
Among the above components (x), neodymium carboxylates and samarium substituted cyclopentadienyl compounds are preferred.

[(Y) component]
A plurality of organoaluminum compounds selected from the following one can be used at the same time.
(Y1) A trihydrocarbyl aluminum compound represented by the formula R ¹² ₃ Al (wherein R ¹² is a hydrocarbon group having 1 to 30 carbon atoms and may be the same or different from each other).
(Y2) Hydrocarbyl aluminum hydride represented by the formula R ¹³ ₂ AlH or R ¹³ AlH ₂ (wherein R ¹³ is a hydrocarbon group having 1 to 30 carbon atoms and may be the same or different from each other).
(Y3) A hydrocarbylaluminoxane compound having a hydrocarbon group having 1 to 30 carbon atoms.
Examples of the component (y) include trialkylaluminum, dialkylaluminum hydride, alkylaluminum dihydride, and alkylaluminoxane. These compounds may be used as a mixture. Among the components (y), a combination of an aluminoxane and another organoaluminum compound is preferable.

[(Z) component]
Although it is a compound selected from the following ones, it is not always necessary when (x) contains a halogen or a non-coordinating anion and (y) contains an aluminoxane.
(Z1) An inorganic or organic compound of an element belonging to Group II, III, or IV having a hydrolyzable halogen (short period type) or a complex compound of these with a Lewis base. For example, alkyl aluminum dichloride, dialkyl aluminum chloride, silicon tetrachloride, tin tetrachloride, a complex of zinc chloride and a Lewis base such as alcohol, a complex of magnesium chloride and a Lewis base such as alcohol, or the like.
(Z2) An organic halide having a structure selected from at least one tertiary alkyl halide, benzyl halide, and allyl halide. For example, benzyl chloride, t-butyl chloride, benzyl bromide, t-butyl bromide and the like.
(Z3) A zinc halide or a complex compound of this with a Lewis base.
(Z4) An ionic compound comprising a non-coordinating anion and a counter cation. An example is triphenylcarbonium tetrakis (pentafluorophenyl) borate.

For the preparation of the catalyst, in addition to the components (x), (y), and (z), the same conjugated diene compound and / or non-conjugated diene monomer as the polymerization monomer is used in combination as necessary. May be. Further, a part or all of the component (x) or the component (z) may be supported on an inert solid, and in this case, it can be carried out by so-called gas phase polymerization.
Although the usage-amount of the said catalyst can be set suitably, normally (x) component is about 0.001-0.5 millimoles per 100g of monomers. Moreover, (y) component / (x) component is about 5-1000 and (z) component / (x) component is about 0.5-10 by molar ratio.

  Examples of the solvent used in the case of solution polymerization include organic solvents inert to the reaction, for example, hydrocarbon solvents such as aliphatic, alicyclic, and aromatic hydrocarbon compounds. Specifically, those having 3 to 8 carbon atoms are preferred, such as propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene, trans-2-butene, Examples thereof include 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 temperature in this polymerization reaction is preferably selected in the range of −80 to 150 ° C., more preferably −20 to 120 ° 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 will depend on the particular material being polymerized, the polymerization medium used and the polymerization temperature, but higher pressures can be used if desired, and such a pressure can be used with a gas inert to the polymerization reaction. It can be obtained by an appropriate method such as pressurization.
In this polymerization reaction, it is desirable that all raw materials involved in the polymerization, such as a catalyst, a solvent, a monomer, etc., from which reaction inhibitors such as water, oxygen, carbon dioxide, and protic compounds are substantially removed are used.

  The modified conjugated diene polymer used in the present invention is a conjugated diene polymer (intermediate polymer) having an active terminus having a cis-1,4-bond content of 75 mol% or more thus obtained. The active terminal is modified by at least a hydrocarbyloxysilane compound, and there are five modes shown below.

First, the first embodiment is a modified conjugated diene system in which the active terminal of the intermediate polymer is first modified with a hydrocarbyloxysilane compound and then secondarily modified with a hydrocarbyloxysilane compound in the presence of a condensation accelerator. It is a polymer.
A second aspect is a modified conjugated diene polymer obtained by first reacting the active terminal of the intermediate polymer with a hydrocarbyloxysilane compound and then further reacting with a carboxylic acid partial ester of a polyhydric alcohol.
In a third aspect, the hydrocarbyloxysilane compound residue and the unreacted hydrocarbyloxysilane introduced into the terminal after the primary modification of the active end of the intermediate polymer with a hydrocarbyloxysilane compound and further in the presence of a condensation accelerator It is a modified conjugated diene polymer obtained by condensation reaction with a compound.
The fourth aspect is a modified conjugated diene polymer obtained by further reacting with a carboxylic acid partial ester of a polyhydric alcohol after the secondary modification in the first aspect.
A fifth aspect is a modified conjugated diene polymer obtained by further reacting with a carboxylic acid partial ester of a polyhydric alcohol after the condensation reaction in the third aspect.

  In the primary modification reaction in each of the above embodiments, it is preferable that the intermediate polymer used has at least 10% polymer chains having a living property.

(Hydrocarbyloxysilane compound)
Examples of the hydrocarbyloxysilane compound used for modification include at least one compound selected from compounds represented by the following general formula (I), general formula (II) or general formula (III) and partial condensates thereof. .

[Wherein A ¹ is (thio) epoxy, (thio) isocyanate, (thio) ketone, (thio) aldehyde, imine, amide, isocyanuric acid trihydrocarbyl ester, (thio) carboxylic acid ester, (thio) carboxylic acid A monovalent group having at least one functional group selected from a metal salt, a carboxylic acid anhydride, a carboxylic acid halide, and a dihydrocarbyl carbonate ester, R ¹ is a single bond or a divalent inert hydrocarbon group , R ² and R ³ each independently represent a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and n is an integer of 0 to 2 , and the case where R ² is plural, R ² may be the same or different, if the OR ³ there are a plurality, the plurality of OR ³ may be the same or different, and in the molecule active Proton and onium salt are not included]
In the present specification, “(thio) epoxy” indicates epoxy or thioepoxy, “(thio) isocyanate” indicates isocyanate or thioisocyanate, “(thio) ketone” indicates ketone or thioketone, “(Thio) aldehyde” refers to aldehyde or thioaldehyde, and “(thio) carboxylic acid” refers to carboxylic acid, thiocarboxylic acid ester or dithiocarboxylic acid.

Including in the formula (I), in the functional groups in A ^1, imine ketimine, aldimine, include amidine, a (thio) carboxylic acid esters, unsaturated carboxylic acid esters such as acrylates and methacrylates. Examples of the metal of the metal salt of (thio) carboxylic acid include alkali metals, alkaline earth metals, Al, Sn, and Zn.

Preferred examples of the divalent inert hydrocarbon group in R ¹ include an alkylene group having 1 to 20 carbon atoms. The alkylene group may be linear, branched or cyclic, but is particularly preferably linear. Examples of the linear alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, an octamethylene group, a decamethylene group, and a dodecamethylene group. Examples of R ² and R ³ include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, and an aralkyl group having 7 to 18 carbon atoms. The alkyl group and alkenyl group may be linear, branched, or cyclic. For example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, decyl group, dodecyl group, cyclopentyl group, cyclohexyl group, vinyl group, propenyl group, allyl group, hexenyl group, octenyl group, cyclopentenyl group, cyclohexenyl group, etc. Is mentioned. In addition, the aryl group may have a substituent such as a lower alkyl group on the aromatic ring, and examples thereof include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. Furthermore, the aralkyl group may have a substituent such as a lower alkyl group on the aromatic ring, and examples thereof include a benzyl group, a phenethyl group, and a naphthylmethyl group.

  n is an integer of 0 to 2, but 0 is preferable, and it is necessary that this molecule has no active proton and onium salt.

  The hydrocarbyloxysilane compound represented by the general formula (I) includes (thio) epoxy group-containing hydrocarbyloxysilane compounds such as 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 epoxy groups in these compounds were replaced with thioepoxy groups Like things Can be exemplified Ku, among these, in particular 3-glycidoxypropyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane are preferable.

  The hydrocarbyloxysilane compound represented by the general formula (I) is N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine as an imine group-containing hydrocarbyloxycyan compound. N- (1-methylethylidene) -3- (triethoxysilyl) -1-propanamine, N-ethylidene-3- (triethoxysilyl) -1-propanamine, N- (1-methylpropylidene)- 3- (Triethoxysilyl) -1-propanamine, N- (4-N, N-dimethylaminobenzylidene) -3- (triethoxysilyl) -1-propanamine, N- (cyclohexylidene) -3- (Triethoxysilyl) -1-propanamine and trimethoxysilyl compounds corresponding to these triethoxysilyl compounds, Preferred examples include a rudiethoxysilyl compound, an ethyldiethoxysilyl compound, a methyldimethoxysilyl compound, and an ethyldimethoxysilyl compound. Among these, N- (1-methylpropylidene) -3- (triethoxy Silyl) -1-propanamine and N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine are preferred.

  The hydrocarbyloxysilane compound represented by the general formula (I) is an imine (amidine) group-containing compound such as 1- [3- (triethoxysilyl) propyl] -4,5-dihydroimidazole, 1- [3 -(Trimethoxysilyl) propyl] -4,5-dihydroimidazole, 3- [10- (triethoxysilyl) decyl] -4-oxazoline, and the like can be mentioned. Among these, 3- (1- Hexamethyleneimino) propyl (triethoxy) silane, (1-hexamethyleneimino) methyl (trimethoxy) silane, 1- [3- (triethoxysilyl) propyl] -4,5-dihydroimidazole and 1- [3- (tri Preferable examples include (methoxysilyl) propyl] -4,5-dihydroimidazole. N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole, N- (3-isopropoxysilylpropyl) -4,5-dihydroimidazole, N- (3-methyldiethoxysilylpropyl)- 4,5-dihydroimidazole and the like can be mentioned, and among them, N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole is preferable.

  Further, the hydrocarbyloxysilane compound represented by the general formula (I) includes 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, and 3-methacryloyloxy as carboxylic acid ester group-containing compounds. Examples thereof include propylmethyldiethoxysilane and 3-methacryloyloxypropyltriisopropoxysilane. Among them, 3-methacryloyloxypropyltrimethoxysilane is preferable.

  In addition, the hydrocarbyloxysilane compound represented by the general formula (I) includes 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and 3-isocyanatopropylmethyldiethoxysilane as isocyanate group-containing compounds. , 3-isocyanatopropyltriisopropoxysilane, etc., among which 3-isocyanatopropyltriethoxysilane is preferred.

  Further, the hydrocarbyloxysilane compound represented by the general formula (I) is a carboxylic acid anhydride-containing compound such as 3-triethoxysilylpropyl succinic anhydride, 3-trimethoxysilylpropyl succinic anhydride, 3-methyl Examples thereof include diethoxysilylpropyl succinic anhydride, among which 3-triethoxysilylpropyl succinic anhydride is preferable.

  One of these hydrocarbyloxysilane compounds may be used alone, or two or more thereof may be used in combination. Moreover, the partial condensate of the said hydrocarbyl oxysilane compound can also be used.

  Next, as the hydrocarbyloxysilane compound, the general formula (II)

[Wherein, A ² is a monovalent group having at least one functional group selected from cyclic tertiary amine, acyclic tertiary amine, pyridine, sulfide and multisulfide, and R ⁴ is a single bond or a double bond. A valent inert hydrocarbon group, R ⁵ and R ⁶ each independently represent a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, m is an integer of 0 to 2, if R ⁵ there are a plurality, the plurality of R ⁵ may be the same or different, if OR ⁶ there are plural, a plurality of OR ⁶ may be the same or different, The molecule does not contain active protons and onium salts. ]
And / or a partial condensate thereof can be used.

  The hydrocarbyloxysilane compound represented by the general formula (II) and / or the partial condensate thereof was introduced into the active end because the direct reaction with the active end does not substantially occur and remains unreacted in the reaction system. Consumed for condensation with hydrocarbyloxysilane compound residues.

In the general formula (II), the acyclic tertiary amine in A ² contains an N, N- (disubstituted) aromatic amine such as N, N- (disubstituted) aniline, and is also a cyclic tertiary amine. The amine can contain a (thio) ether as part of the ring. Divalent inactive hydrocarbon group among R ^4, the ^{R 5} and ^{R 6} are the same as those respectively described ^R 1, ^{R 2} and ^{R 3} in the general formula (I). It is necessary that this molecule does not have active protons and onium salts.
In the present specification, “(thio) ether” refers to ether or thioether.

  The hydrocarbyloxysilane compound represented by the general formula (II) is a non-cyclic tertiary amine group-containing hydrocarbyloxysilane compound such as 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-dibutylamino Examples thereof include propyl (triethoxy) silane, among which 3-diethylaminopropyl (triethoxy) silane and 3-dimethylaminopropyl (triethoxy) silane are preferable.

  Further, the hydrocarbyloxysilane compound represented by the general formula (II) is a cyclic tertiary amine group-containing hydrocarbyloxysilane compound such as 3- (1-hexamethyleneimino) propyl (triethoxy) silane, 3- (1-hexa). Methyleneimino) propyl (trimethoxy) silane, (1-hexamethyleneimino) methyl (trimethoxy) silane, (1-hexamethyleneimino) methyl (triethoxy) silane, 2- (1-hexamethyleneimino) ethyl (triethoxy) silane, 2- (1-hexamethyleneimino) ethyl (trimethoxy) silane, 3- (1-pyrrolidinyl) propyl (triethoxy) silane, 3- (1-pyrrolidinyl) propyl (trimethoxy) silane, 3- (1-heptamethyleneimino) Propyl (triethoxy) sila And 3- (1-dodecamethyleneimino) propyl (triethoxy) silane, 3- (1-hexamethyleneimino) propyl (diethoxy) methylsilane, and 3- (1-hexamethyleneimino) propyl (diethoxy) ethylsilane. . Of these, 3- (1-hexamethyleneimino) propyl (triethoxy) silane is preferred.

  Furthermore, the hydrocarbyloxysilane compound represented by the general formula (II) includes other hydrocarbyloxysilane compounds such as 2- (trimethoxysilylethyl) pyridine, 2- (triethoxysilylethyl) pyridine, 4-ethylpyridine and the like. Can be mentioned.

  One of these hydrocarbyloxysilane compounds may be used alone, or two or more thereof may be used in combination. Moreover, the partial condensate of these hydrocarbyl oxysilane compounds can also be used.

  The hydrocarbyloxysilane compound further includes a general formula (III)

[Wherein A ³ represents alcohol, thiol, primary amine and onium salt thereof, cyclic secondary amine and onium salt thereof, acyclic secondary amine and onium salt thereof, onium salt of cyclic tertiary amine, acyclic tertiary amine An onium salt of an amine, a group having an aryl or arylalkyl Sn bond, a monovalent group having at least one functional group selected from sulfonyl, sulfinyl and nitrile, R ⁷ is a single bond or a divalent inert hydrocarbon group , R ⁸ and R ⁹ each independently represent a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, q is an integer of 0 to 2 , and the case where R ⁸ is plural, R ⁸ may be the same or different, if the OR ⁹ there are a plurality, the plurality of OR ⁹ may be the same or different. ]
And / or a partial condensate thereof can be used.

In the general formula (III), the primary amine in A ³ includes aromatic amines such as aniline, and the acyclic secondary amine is N- (monosubstituted) aromatic such as N- (monosubstituted) aniline. Includes amines. Further, onium salts of acyclic tertiary amines include onium salts of N, N- (disubstituted) aromatic amines such as N, N- (disubstituted) aniline. Also. In the case of a cyclic secondary amine or a cyclic tertiary amine, (thio) ether can be contained as a part of the ring. Divalent inactive hydrocarbon group out of R ^7, the ^{R 8} and ^{R 9} are the same as those respectively described ^R 1, ^{R 2} and ^{R 3} in the general formula (I).

  Examples of the hydrocarbyloxysilane compound represented by the general formula (III) include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, hydroxymethyltrimethoxysilane, hydroxymethyltriethoxysilane, mercaptomethyltrimethoxy. Silane, mercaptomethyltriethoxysilane, aminophenyltrimethoxysilane, aminophenyltriethoxysilane, 3- (N-methylamino) propyltrimethoxysilane, 3- (N-methylamino) propyltriethoxysilane, octadecyldimethyl (3 -Trimethylsilylpropyl) ammonium chloride, octadecyldimethyl (3-triethylsilylpropyl) ammonium chloride, cyanomethyltrimethoxysilane, cyanomethyltrie Kishishiran, can be exemplified sulfonyl methyltrimethoxysilane, sulfonyl methyltriethoxysilane, sulfinyl methyltrimethoxysilane, a sulfinyl methyl triethoxysilane.

One of these hydrocarbyloxysilane compounds may be used alone, or two or more thereof may be used in combination. Moreover, the partial condensate of the said hydrocarbyl oxysilane compound can also be used.
In addition, the partial condensate of the hydrocarbyloxysilane compound represented by the general formulas (I), (II), and (III) is a part of SiOR of the hydrocarbyloxysilane compound (not all), and SiOSi Say something combined.

  In the present invention, in the case of the first aspect, the third aspect, the fourth aspect, and the fifth aspect, the reaction with the remaining or newly added hydrocarbyloxysilane compound in the presence of a condensation accelerator. First, an intermediate polymer having an active end reacts with a substantially stoichiometric amount of a hydrocarbyloxysilane compound added to the reaction system to introduce a hydrocarbyloxysilyl group at substantially all of the ends. (Primary modification), and by reacting the hydrocarbyloxysilyl compound with the hydrocarbyloxysilyl group introduced above, more hydrocarbyloxysilane compound residues than the equivalent amount are introduced into the active terminal.

  In the present invention, when the hydrocarbyloxysilane compound is an alkoxysilyl compound, the condensation reaction between alkoxysilyl groups in the first aspect, the third aspect, the fourth aspect, and the fifth aspect is (residual or It preferably occurs between the newly added free alkoxysilane and the alkoxysilyl group at the end of the polymer, and in some cases, preferably occurs between the alkoxysilyl groups at the end of the polymer. is necessary. Therefore, when an alkoxysilane compound is newly added, it is preferable from the viewpoint of efficiency that the hydrolyzability of the alkoxysilyl group does not exceed the hydrolyzability of the alkoxysilyl group at the polymer terminal. For example, a trimethoxysilyl group-containing compound having a large hydrolyzability is used for the primary modified alkoxysilane I, and an alkoxysilyl group (for example, a triethoxysilyl group) having a lower hydrolyzability than the newly added alkoxysilane II. A combination using a compound containing is preferred. On the other hand, for example, it is included in the scope of the present invention that the alkoxysilane I contains a triethoxysilyl group and the II contains a trimethoxysilyl group, but it is not preferable from the viewpoint of reaction efficiency.

The denaturation reaction in the present invention may be either a solution reaction or a solid phase reaction, but a solution reaction (a solution containing an unreacted monomer used during polymerization may be suitable). Moreover, there is no restriction | limiting in particular about the form of this modification | denaturation reaction, You may carry out using a batch type reactor, You may carry out by a continuous type using apparatuses, such as a multistage continuous type reactor and an in-line mixer. In addition, it is important to carry out the modification reaction after completion of the polymerization reaction and before performing various operations necessary for solvent removal treatment, water treatment, heat treatment, polymer isolation, and the like.
As the temperature of the modification reaction, the polymerization temperature of the conjugated diene polymer can be used as it is. Specifically, a preferable range is 20 to 100 ° C. If the temperature is low, the viscosity of the polymer tends to increase, and if the temperature is high, the polymerization active terminal tends to be deactivated.

  Next, in order to promote the secondary modification, it is preferably performed in the presence of a condensation accelerator. As this condensation accelerator, a combination of a metal compound generally known as a curing catalyst for alkoxy condensation curable room temperature crosslinking (RTV) silicone and water can be used. For example, a combination of tin carboxylate and / or titanium alkoxide and water can be preferably mentioned. There is no particular limitation on the method of charging the condensation accelerator into the reaction system. A solution of an organic solvent compatible with water such as alcohol may be used, or water may be directly injected, dispersed, or dissolved in the hydrocarbon solution using various chemical engineering techniques.

  Such a condensation accelerator is preferably composed of at least one compound selected from the compounds represented by formula (IV), formula (V) and formula (VI) and water. .

Carbonate having 3 to 20 carbon atoms of tin of oxidation number 2 represented by general formula (IV):
Sn (OCOR ¹⁰ ) ₂ .... (IV)
[Wherein, R ¹⁰ is an organic group having 2 to 19 carbon atoms, and when there are a plurality of them, they may be the same or different. ]

Tin compound of oxidation number 4 represented by general formula (V):
R ¹¹ _r SnA ⁴ _t B ¹ _(4- tr ₎ (V)
[Wherein, r is an integer of 1 to 3, t is an integer of 1 or 2, and t + r is an integer of 3 or 4. R ¹¹ is an aliphatic hydrocarbon group having 1 to 30 carbon atoms, and B ¹ is a hydroxyl group or a halogen. A ⁴ represents (a) an aliphatic carboxylic acid residue having 2 to 30 carbon atoms, (b) a 1,3-dicarbonyl-containing hydrocarbon group having 5 to 30 carbon atoms, and (c) a hydrocarbyl having 3 to 30 carbon atoms. A group selected from an oxy group and (d) a siloxy group having a total of three substitutions (which may be the same or different) with a hydrocarbyl group having 1 to 20 carbon atoms and / or a hydrocarbyloxy group having 1 to 20 carbon atoms. , R ¹¹ may be the same or different when there are a plurality of R ¹¹ , and may be the same or different when there are a plurality of A ⁴ . ]

Titanium compound having an oxidation number of 4 represented by the general formula (VI):
A ⁵ _x TiB ² _(4-x) (VI)
[Wherein x is an integer of 2 or 4. A ⁵ is (1) a C 3-30 hydrocarbyloxy group, (2) a C 1-30 alkyl group and / or a C 1-20 hydrocarbyloxy group, which is a total of three substituted siloxy groups, If the A ⁵ there are a plurality may be the same or different. B ² is a 1,3-dicarbonyl-containing hydrocarbon group having 5 to 30 carbon atoms, and when there are a plurality of B ² , they may be the same or different. ]

  Examples of the carboxylic acid salt of tin having an oxidation number of 2 represented by the general formula (IV) include bis (2-ethylhexanoic acid) tin, tin dioleate and tin dilaurate represented by the general formula (V). Among the tin compounds having an oxidation number of 4 which are used, examples of the tin carboxylate of (a) include tetravalent dihydrocarbyltin dicarboxylates (including bis (hydrocarbyldicarboxylic acid) salts), monocarboxylates Hydroxide or the like (b) having a 1,3-dicarbonyl-containing hydrocarbon group having 5 to 30 carbon atoms includes bis (1,3-diketonate) and the like (c) having 3 to 30 carbon atoms. As those having a hydrocarbyloxy group, the alkoxy halide is (d) a total of three substitutions (even if they are the same) with a hydrocarbyl group having 1 to 20 carbon atoms and / or a hydrocarbyloxy group having 1 to 20 carbon atoms. Examples of those having a siloxy group which may have been made include alkoxy (trihydrocarbylsiloxide), alkoxy (dihydrocarbylalkoxysiloxide), bis (trihydrocarbylsiloxide), bis (dihydrocarbylalkoxysiloxide) and the like Are preferable. The hydrocarbon group condensed with tin preferably has 4 or more carbon atoms, and more preferably has 4 to 8 carbon atoms.

  Further, as the titanium compound having an oxidation number of 4 represented by the general formula (VI), tetraalkoxide or tetrakis (trihydrocarbyloxysiloxide) of titanium having an oxidation number of 4 or diisopropoxybis (acetylacetonate) titanium Dialkoxybis (1,3-diketonate) titanium and the like.

  The water in the condensation accelerator is preferably used in the form of a simple substance, a solution of alcohol or the like, or a dispersed micelle in a hydrocarbon solvent, and if necessary, such as adsorbed water on the solid surface or hydrated water of hydrate. Water that is potentially contained in a compound capable of releasing water in the reaction system can also be used effectively.

  The metal compound and water forming the condensation accelerator may be added separately to the reaction system or mixed immediately before use as a mixture, but long-term storage of the mixture is preferable because it causes decomposition of the metal compound. Absent.

  As the use amount of the condensation accelerator, it is preferable that the number of moles of the metal of the metal compound and the water effective for the reaction is 0.1 or more in terms of the molar ratio to the total amount of hydrocarbyloxysilyl groups present in the reaction system. . Although the upper limit varies depending on the purpose and reaction conditions, it is preferable that there is effective water having a molar ratio of about 0.5 to 3 with respect to the total amount of hydrocarbyloxysilyl groups condensed at the polymer terminal before the condensation treatment. The molar ratio of the metal of the metal compound to water effective for the reaction varies depending on the required reaction conditions, but is preferably about 1: 0.5 to 1:20.

In the present invention, in the second aspect, the fourth aspect and the fifth aspect of the modified conjugated diene polymer, the polycarboxylic alcohol carboxylic acid partial ester is derived from the hydrocarbyloxysilane compound introduced at the polymerization terminal. An operation of reacting with the group and stabilizing the group is performed.
Here, the carboxylic acid partial ester of a polyhydric alcohol is an ester of a polyhydric alcohol and a carboxylic acid and means a partial ester having one or more hydroxyl groups. Specifically, an ester of a saccharide having 4 or more carbon atoms or a modified saccharide and a fatty acid is preferably used. This ester is more preferably (i) a fatty acid partial ester of a polyhydric alcohol, particularly a partial ester of a saturated higher fatty acid having 10 to 20 carbon atoms or an unsaturated higher fatty acid and a polyhydric alcohol (monoester, diester, triester). And (b) an ester compound in which 1 to 3 partial esters of a polyvalent carboxylic acid and a higher alcohol are bonded to the polyhydric alcohol.

  The polyhydric alcohol used as the raw material for the partial ester is preferably a saccharide having 5 or 6 carbon atoms having at least three hydroxyl groups (which may be hydrogenated or not hydrogenated), glycol, A polyhydroxy compound or the like is used. The raw fatty acid is preferably a saturated or unsaturated fatty acid having 10 to 20 carbon atoms, and for example, stearic acid, lauric acid, and palmitic acid are used.

Among the fatty acid partial esters of polyhydric alcohols, sorbitan fatty acid esters are preferred, specifically, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate and And sorbitan trioleate.
Commercially available products include “SPAN60” (sorbitan stearate), “SPAN80” (sorbitan monooleate), “SPAN85” (sorbitan trioleate) and the like as trademarks of ICI.
The amount of the partial ester added is preferably about 0.2 to 10 mol, particularly 1 to 10 mol, relative to 1 mol of the hydrocarbyloxysilyl group imparted to the intermediate polymer.

As the modified conjugated diene polymer thus produced, modified polybutadiene having a cis-1,4-bond amount of 75 mol% or more is preferable from the viewpoint of the performance of the rubber composition for tires.
The modified conjugated diene polymer has a large dispersion improving effect on reinforcing fillers, particularly silica, and lowers E ′ (dynamic storage elastic modulus) in the whole temperature range. It is possible to increase the decrease. Therefore, the wet grip performance of the tire can be further enhanced.
In addition, the loss factor (tan δ) is greatly reduced, and compared to the case of using ordinary polybutadiene rubber, it is possible to increase the decrease in high temperature (60 ° C) while reducing the decrease in 0 ° C. Therefore, even in the high-filled silica formulation, it works simultaneously to improve the balance between wet grip performance and low heat buildup. Further, the wear resistance can be improved by the effect of improving the dispersion of the reinforcing filler.

<Other rubber components>
The diene rubber may contain a rubber component (other rubber components) other than natural rubber and the modified conjugated diene polymer described above. The rubber component is not particularly limited, but other than the above-described modified conjugated diene polymer, aromatic vinyl-conjugated diene copolymer rubber, isoprene rubber (IR), butadiene rubber (BR), acrylonitrile-butadiene copolymer. Polymerized rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), chloroprene rubber (CR) and the like can be mentioned. Examples of the aromatic vinyl-conjugated diene copolymer rubber include styrene butadiene rubber (SBR) and styrene isoprene copolymer rubber.
The content of other rubber components in the diene rubber is not particularly limited, but is preferably 0 to 30% by mass.

〔silica〕
The silica contained in the composition of the present invention is not particularly limited, and any conventionally known silica compounded in a rubber composition for uses such as tires can be used.
Examples of the silica include wet silica, dry silica, fumed silica, diatomaceous earth, and the like. As the silica, one type of silica may be used alone, or two or more types of silica may be used in combination.

The cetyltrimethylammonium bromide (CTAB) adsorption specific surface area of silica is not particularly limited, for the reasons the effects of the present invention is more excellent, is preferably 50 to 300 m ² / g, it is 100 to 250 m ² / g Is more preferable.
In the present specification, the CTAB adsorption specific surface area is a value obtained by measuring the CTAB adsorption amount on the silica surface in accordance with JIS K6217-3: 2001 “Part 3: Determination of specific surface area—CTAB adsorption method”.

  In the composition of the present invention, the content of silica is 20 to 100 parts by mass with respect to 100 parts by mass of the diene rubber. Especially, it is preferable that it is 30-90 mass parts from the reason which the effect of this invention is more excellent, and it is more preferable that it is 50-80 mass parts.

[Specific cured product]
The cured product contained in the composition of the present invention is a cured product obtained by curing a crosslinkable oligomer or polymer that is incompatible with the diene rubber, and has a JIS A hardness of 3 to 45, which is a cured product (hereinafter, referred to as “cured product”). It is also called “specific cured product”).

“Incompatible with (the diene rubber)” does not mean that it is incompatible with all the rubber components included in the diene rubber, but is not compatible with the diene rubber and the crosslinkable oligomer or polymer. The specific components used are incompatible with each other. That is, the crosslinkable oligomer or polymer only needs to be incompatible with the component actually contained in the diene rubber, and the rubber component that is not actually contained in the diene rubber (for example, the above-mentioned “others” It is not necessary to be incompatible with the rubber component ")". For example, in the examples described later, since the diene rubber is composed of natural rubber and a modified conjugated diene polymer, the crosslinkable polymer may be incompatible with the natural rubber and the modified conjugated diene polymer.
The “cured cured product” refers to a cured product obtained by curing a crosslinkable oligomer or polymer in advance before mixing and preparing the composition of the present invention.
“JIS A hardness” refers to the durometer hardness specified in JIS K6253-3: 2012, and the hardness measured at a temperature of 25 ° C. with a type A durometer.

<Crosslinkable oligomer or polymer>
The crosslinkable oligomer or polymer is not particularly limited as long as it is an oligomer or polymer that is incompatible with the diene rubber and has crosslinkability.
“Compatible” means that two (or a plurality of) different molecular chains are uniformly compatible at the molecular level (completely mixed at the molecular level). “No” intends not to mix completely at the molecular level.

  Examples of the crosslinkable oligomer or polymer include polyether-based, polyester-based, polyolefin-based, polycarbonate-based, aliphatic-based, saturated hydrocarbon-based, acrylic-based, plant-derived or siloxane-based polymers or copolymers. Is mentioned.

  Among these, from the viewpoint of thermal stability, molecular chain flexibility, hydrolysis resistance, etc., the crosslinkable oligomer or polymer is preferably a polyether-based or siloxane-based polymer or copolymer. .

Examples of the polyether polymer or copolymer include polyethylene glycol, polypropylene glycol (PPG), polypropylene triol, ethylene oxide / propylene oxide copolymer, polytetramethylene ether glycol (PTMEG), and sorbitol polyol. Is mentioned.
Examples of the siloxane-based polymer or copolymer include a siloxane structure represented by-(Si (R ¹ ) (R ² ) O)-(wherein R ¹ and R ² are each independently, And a polymer or copolymer having a main chain of an alkyl group having 1 to 4 carbon atoms or a phenyl group).

The crosslinkable oligomer or polymer preferably has a silane functional group because a cured product is easily formed by cross-linking between molecules.
The silane functional group is also called a so-called crosslinkable silyl group. Specific examples thereof include hydrolyzable silyl groups; silanol groups; silanol groups substituted with acetoxy group derivatives, enoxy group derivatives, oxime group derivatives, amine derivatives, and the like. Functional group; and the like.

Specific examples of the hydrolyzable silyl group include an alkoxysilyl group, an alkenyloxysilyl group, an acyloxysilyl group, an aminosilyl group, an aminooxysilyl group, an oximesilyl group, and an amidosilyl group.
Among these, an alkoxysilyl group is preferable because the balance between hydrolyzability and storage stability is good. Specifically, an alkoxysilyl group represented by the following formula (1) is more preferable, and a methoxysilyl group is preferable. More preferred is an ethoxysilyl group.

(In the formula, R ¹ represents an alkyl group having 1 to 4 carbon atoms, R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, a represents an integer of 1 to 3. a is 2 or 3) In this case, the plurality of R ¹ may be the same or different, and when a is 1, the plurality of R ¹ may be the same or different.)

  The silane functional group preferably has at least at the end of the main chain of the crosslinkable oligomer or polymer. When the main chain is linear, it preferably has 1.5 or more, It is more preferable to have two or more. On the other hand, when the main chain is branched, it is preferably 3 or more.

The weight-average molecular weight or number-average molecular weight of the crosslinkable oligomer or polymer is 300 to 30,000 because the dispersibility of the obtained cured product in the diene rubber and the kneading processability of the rubber composition become good. Is preferable, and 2,000 to 20,000 is more preferable.
The weight average molecular weight and the number average molecular weight are both measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

The curing method for curing the crosslinkable oligomer or polymer is not particularly limited. For example, there is a method of curing using at least one catalyst selected from the group consisting of an acid catalyst, an alkali catalyst, a metal catalyst, and an amine catalyst. Can be mentioned.
Among these, a method of curing using an acid catalyst or a metal catalyst is preferable because of high curing efficiency.

Specific examples of the acid catalyst include, for example, lactic acid, phthalic acid, lauric acid, oleic acid, linoleic acid, linolenic acid, naphthenic acid, octenoic acid, octylic acid (2-ethylhexanoic acid), formic acid, Examples include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, benzoic acid, oxalic acid, malic acid, citric acid, and the like. In addition, two or more kinds may be used in combination.
As the acid catalyst, from the viewpoint of acidity and dispersibility, it is preferable to use an acid that is liquid at room temperature, and more specifically, lactic acid and formic acid are more preferable.

Examples of the metal catalyst include organometallic compounds such as tin octylate, alkali metal alcoholates, and the like.
Specifically, tin carboxylates such as dimethyltin dilaurate, dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, tin octylate and tin naphthenate; titanates such as tetrabutyl titanate and tetrapropyl titanate; aluminum trisacetyl Organoaluminum compounds such as acetonate, aluminum trisethylacetoacetate, diisopropoxyaluminum ethylacetoacetate; Chelate compounds such as zirconium tetraacetylacetonate and titanium tetraacetylacetonate; Octanes such as lead octoate and bismuth octoate Acid metal salt; and the like.
As the metal catalyst, tin carboxylates are more preferably used from the viewpoint of acidity.

  The hardness of the cured product is 3 to 45 in terms of JIS A hardness, and 3 to 20 is preferable and 3 to 15 is more preferable because the effect of the present invention is more excellent.

The average particle size of the cured product in the composition of the present invention prepared by mixing the cured product is excellent in dispersibility in the diene rubber, and the on-ice performance and wear resistance of the studless tire are improved. For the reason, it is preferably a particulate material having an average particle diameter of 5 to 250 μm.
The average particle size of the cured product in the composition of the present invention was observed by analyzing the image of the cross section of the vulcanized specimen of the composition of the present invention with an electron microscope (magnification: about 500 to 2000 times). The maximum length of a product particle is measured with an arbitrary 10 or more particles, and is an averaged value.

  In the composition of the present invention, the content of the cured product is 0.3 to 30 parts by mass with respect to 100 parts by mass of the diene rubber. Especially, 0.5-25 mass parts is preferable and 1-15 mass parts is preferable from the reason for which the effect of this invention is more excellent.

[Optional ingredients]
The composition of this invention can contain another component (arbitrary component) in the range which does not impair the effect and the objective as needed.
Examples of the optional component include carbon black, silane coupling agent, aromatic modified terpene resin, thermally expandable microcapsule, filler, zinc oxide (zinc white), stearic acid, anti-aging agent, wax, and processing aid. And various additives generally used in rubber compositions such as oil, liquid polymer, thermosetting resin, vulcanizing agent (for example, sulfur), and vulcanization accelerator.

<Aromatic modified terpene resin>
The composition of the present invention preferably contains an aromatic-modified terpene resin because the effects of the present invention are more excellent. The aromatic modified terpene resin is an aromatic modified terpene resin having a softening point of 60 to 150 ° C. (hereinafter also referred to as “specific aromatic modified terpene resin”) because the effect of the present invention is more excellent. preferable. The softening point is more preferably 70 to 140 ° C. because the effect of the present invention is more excellent.
Here, the softening point is a Vicat softening point measured according to JIS K7206: 1999.
In the composition of the present invention, the content of the aromatic modified terpene resin is not particularly limited, but is 2 to 20 parts by mass with respect to 100 parts by mass of the diene rubber because the effect of the present invention is more excellent. It is preferably 5 to 15 parts by mass.

<Thermal expandable microcapsules>
The composition of the present invention preferably contains a heat-expandable microcapsule because the effect of the present invention is more excellent.
The thermally expandable microcapsule is a thermally expandable thermoplastic resin particle in which a liquid that is vaporized by heat to generate a gas is encapsulated in a thermoplastic resin, and the particle is heated to a temperature equal to or higher than its expansion start temperature, usually 130 to 190. It expands by heating at a temperature of ° C., and becomes gas-filled thermoplastic resin particles in which a gas is sealed in an outer shell made of the thermoplastic resin.

In the thermoplastic resin, the expansion start temperature is preferably 100 ° C. or higher, and more preferably 120 ° C. or higher. The maximum expansion temperature is preferably 150 ° C. or higher, and more preferably 160 ° C. or higher.
As the thermoplastic resin, for example, a polymer of (meth) acrylonitrile or a copolymer having a high (meth) acrylonitrile content is preferably used. As the other monomer (comonomer) in the case of the copolymer, monomers such as vinyl halide, vinylidene halide, styrene monomer, (meth) acrylate monomer, vinyl acetate, butadiene, vinylpyridine, chloroprene are used. .
The thermoplastic resin is divinylbenzene, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, allyl. It may be made crosslinkable with a crosslinking agent such as (meth) acrylate, triacryl formal, triallyl isocyanurate or the like. The crosslinked form is preferably uncrosslinked, but may be partially crosslinked so as not to impair the properties as a thermoplastic resin.
Examples of the liquid that is vaporized by heat to generate gas include hydrocarbons such as n-pentane, isopentane, neopentane, butane, isobutane, hexane, and petroleum ether; methyl chloride, methylene chloride, dichloroethylene, trichloroethane, Liquids such as chlorinated hydrocarbons such as trichloroethylene;

The heat-expandable microcapsule is not particularly limited as long as it is a heat-expandable microcapsule that expands by heat to become a gas-filled thermoplastic resin, and may be used alone or in combination of two or more. Good.
The particle size of the thermally expandable microcapsule before expansion is preferably 5 to 300 μm, more preferably 10 to 200 μm.

  As such thermally expandable microcapsules, commercially available products can be used. Specifically, for example, EXPANCEL 091DU-80, EXPANCEL 092DU-120 manufactured by EXPANCEL; Sphere F-85, Microsphere F-100;

  In the composition of the present invention, the content of the heat-expandable microcapsules is not particularly limited, but is preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the diene rubber, and 1 to 10 parts by mass. It is more preferable that

<Carbon black>
The composition of the present invention preferably contains carbon black for the reason that the effects of the present invention are more excellent.
The carbon black is not particularly limited, and for example, various grades such as SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, IISAF-HS, HAF-HS, HAF, HAF-LS, and FEF are used. can do.
The nitrogen adsorption specific surface area (N ₂ SA) of the carbon black is not particularly limited, but is preferably 50 to ²⁰⁰ m ² / g, more preferably 70 to 150 m ² / g, because the effect of the present invention is more excellent. Is more preferable.
Here, the nitrogen adsorption specific surface area (N ₂ SA) is determined according to JIS K6217-2: 2001 “Part 2: Determination of specific surface area—nitrogen adsorption method—single point method”. It is a measured value.

  Although the content of the carbon black is not particularly limited, it is preferably 1 to 200 parts by mass, and 10 to 100 parts by mass with respect to 100 parts by mass of the diene rubber because the effect of the present invention is more excellent. It is more preferable.

<Silane coupling agent>
The composition of the present invention preferably contains a silane coupling agent because the effects of the present invention are more excellent.
The silane coupling agent is not particularly limited as long as it is a silane compound having a hydrolyzable group and an organic functional group.
The hydrolyzable group is not particularly limited, and examples thereof include an alkoxy group, a phenoxy group, a carboxyl group, and an alkenyloxy group. Of these, an alkoxy group is preferable. When the hydrolyzable group is an alkoxy group, the alkoxy group preferably has 1 to 16 carbon atoms, more preferably 1 to 4 carbon atoms. As a C1-C4 alkoxy group, a methoxy group, an ethoxy group, a propoxy group etc. are mentioned, for example.

The organic functional group is not particularly limited, but is preferably a group capable of forming a chemical bond with an organic compound, and examples thereof include an epoxy group, a vinyl group, an acryloyl group, a methacryloyl group, an amino group, and a mercapto group. Of these, a mercapto group is preferable.
A silane coupling agent may be used individually by 1 type, and may use 2 or more types together.

  The silane coupling agent is preferably a sulfur-containing silane coupling agent.

  Specific examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, mercaptopropyltrimethoxy. Silane, mercaptopropyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl-tetrasulfide, trimethoxysilylpropyl-mercaptobenzothiazole tetrasulfide, triethoxysilylpropyl-methacrylate-monosulfide, dimethoxymethylsilyl Examples thereof include propyl-N, N-dimethylthiocarbamoyl-tetrasulfide, and one of these may be used alone, or two or more thereof may be used in combination.

  In the composition of the present invention, the content of the silane coupling agent is not particularly limited, but for the reason that the effect of the present invention is more excellent, it is preferably 2 to 20% by mass with respect to the silica content described above. It is preferable that it is 5-15 mass%.

[Method of preparing rubber composition for tire]
The production method of the composition of the present invention is not particularly limited, and specific examples thereof include, for example, kneading the above-described components using a known method and apparatus (for example, a Banbury mixer, a kneader, a roll, etc.). The method etc. are mentioned. When the composition of the present invention contains sulfur or a vulcanization accelerator, components other than sulfur and the vulcanization accelerator are first mixed at a high temperature (preferably 100 to 155 ° C.) and cooled, and then sulfur or It is preferable to mix a vulcanization accelerator.
The composition of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

  As described above, the composition of the present invention is excellent in performance on ice, wet grip performance, low heat build-up property, and wear resistance, and thus is particularly suitable for studless tires.

[Pneumatic tire]
The pneumatic tire of the present invention is a pneumatic tire using the above-described composition of the present invention. Especially, it is preferable that it is a pneumatic tire which used the composition of this invention for the tread.
FIG. 1 shows a schematic partial sectional view of a tire representing an example of an embodiment of the pneumatic tire of the present invention, but the pneumatic tire of the present invention is not limited to the embodiment shown in FIG.

In FIG. 1, reference numeral 1 represents a bead portion, reference numeral 2 represents a sidewall portion, and reference numeral 3 represents a tire tread portion.
Further, a carcass layer 4 in which fiber cords are embedded is mounted between the pair of left and right bead portions 1, and the end of the carcass layer 4 extends from the inside of the tire to the outside around the bead core 5 and the bead filler 6. Wrapped and rolled up.
Further, in the tire tread portion 3, a belt layer 7 is disposed over the circumference of the tire on the outside of the carcass layer 4.
Moreover, in the bead part 1, the rim cushion 8 is arrange | positioned in the part which touches a rim | limb.
The tire tread portion 3 is formed of the above-described composition of the present invention.

  The pneumatic tire of the present invention can be manufactured, for example, according to a conventionally known method. Moreover, as gas with which a tire is filled, inert gas, such as nitrogen, argon, helium other than the air which adjusted normal or oxygen partial pressure, can be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

(Synthesis example)
The modified conjugated diene polymer and the specific cured product were synthesized as follows.

<Synthesis of Modified Conjugated Diene Polymer>
(1) Preparation of catalyst In a glass bottle with a volume of about 100 ml with a rubber stopper, dried and nitrogen-substituted, 7.11 g of cyclohexane solution of butadiene (15.2% by mass), cyclohexane of neodymium neodecanoate, in the following order: 0.59 ml of a solution (0.56M), 10.32 ml of a toluene solution of methylaluminoxane MAO (PMAO manufactured by Tosoh Akzo) (aluminum concentration: 3.23M), a hexane solution of diisobutylaluminum hydride (manufactured by Kanto Chemical) (0.90M) ) 7.77 ml was added and aged at room temperature for 2 minutes, then 1.45 ml of hexane solution (0.95M) of chlorinated diethylaluminum (manufactured by Kanto Chemical) was added and aged for 15 minutes with occasional stirring at room temperature. . The concentration of neodymium in the catalyst solution thus obtained was 0.011 M (mol / liter).

(2) Production of Intermediate Polymer A glass bottle with a volume of about 900 ml with a rubber stopper, which was dried and nitrogen-substituted, was charged with a dry-purified 1,3-butadiene cyclohexane solution and dry cyclohexane, respectively. 400 g of a cyclohexane solution containing 12.5% by mass of butadiene was charged. Next, 2.28 ml (0.025 mmol in terms of neodymium) of the catalyst solution prepared in the above (1) was added, and polymerization was performed in a 50 ° C. hot water bath for 1.0 hour to produce an intermediate polymer. The resulting polymer microstructure has a cis-1,4-bond content of 95.5 mol%, a trans-1,4-bond content of 3.9 mol%, and a vinyl bond content of 0.6 mol%. Hot. These microstructures (cis-1,4-bond content, trans-1,4-bond content, vinyl bond content) were determined by Fourier transform infrared spectroscopy (FT-IR).

(3) Primary denaturation treatment As the primary denaturing agent, GPMOS becomes 23.5 molar equivalents to neodymium as a hexane solution (1.0 M) of 3-glycidoxypropyltrimethoxysilane (GPMOS). Thus, the first modification was performed by adding the polymer solution obtained in the above (2) and treating at 50 ° C. for 60 minutes.

(4) Treatment after secondary modification Subsequently, 1.76 ml (equivalent to 70.5 eq / Nd) of a cyclohexane solution (1.01 M) of bis (2-ethylhexanoate) tin (BEHAS) as a condensation accelerator. ) And 32 μl of ion-exchanged water (equivalent to 70.5 eq / Nd) were added and treated in a hot water bath at 50 ° C. for 1.0 hour. Thereafter, 2 ml of an isopropanol 5% solution of the antioxidant 2,2-methylene-bis (4-ethyl-6-tert-butylphenol) (NS-5) was added to the polymerization system to stop the reaction, and a trace amount of NS Re-precipitation was performed in isopropanol containing -5, and drum drying was performed to obtain a modified conjugated diene polymer. The Mooney viscosity ML _{1 + 4} (100 ° C.) of the resulting modified conjugated diene polymer was measured at 100 ° C. using an RLM-01 type tester manufactured by Toyo Seiki Seisakusho. The microstructure after modification was similar to that of the intermediate polymer.

<Synthesis of specific cured product>
For 10 parts by mass of paste-form product of hydrolyzable silyl group-terminated polyoxypropylene glycol (polypropylene glycol having hydrolyzable silyl group at the end) (MS polymer S810, manufactured by Kaneka Corporation) (crosslinkable polymer), lactic acid 0.1 parts by mass of (acid catalyst) was added.
Subsequently, after fully stirring, the specific hardened | cured material was synthesize | combined by making it harden | cure in normal temperature for 2 days.
The specific cured product 1 obtained had a JIS A hardness of 8. Moreover, the average particle diameter of the specific hardened | cured material in the vulcanized rubber test piece mentioned later was 38 micrometers.

[Preparation of rubber composition for tire]
The components shown in Table 1 below were blended in proportions (parts by mass) shown in the same table.
Specifically, first, the components excluding sulfur and the vulcanization accelerator in the components shown in Table 1 below were raised to around 150 ° C. using a 1.7 liter closed Banbury mixer, and then for 5 minutes. After mixing, the mixture was discharged and cooled to room temperature to obtain a master batch. Furthermore, using the Banbury mixer, sulfur and a vulcanization accelerator were mixed into the obtained master batch to obtain a tire rubber composition.

[Evaluation]
The obtained tire rubber composition was press vulcanized at 170 ° C. for 10 minutes in a predetermined mold to prepare a vulcanized rubber test piece. And the following evaluation was performed about the obtained vulcanized rubber test piece.

<Performance on ice>
A vulcanized rubber test piece was attached to a flat cylindrical base rubber and measured with an inside drum type on-ice friction tester, measuring temperature: −1.5 ° C., load: 5.5 kg / cm ³ , drum rotation speed: 25 km / hour Under the conditions, the friction coefficient on ice was measured.
The results are shown in Table 1 (in the column “Performance on ice” in Table 1). The result was expressed as an index with the friction coefficient on ice of the standard example as 100. The larger the index, the greater the frictional force between rubber and ice, and the better the performance on ice when used as a tire.

<Tan δ (0 ° C.)>
The vulcanized rubber test piece was subjected to tan δ in accordance with JIS K6394: 2007 using a viscoelastic spectrometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.) under conditions of an elongation deformation strain rate of 10% ± 2%, a frequency of 20 Hz, and a temperature of 0 ° C. (0 ° C.) was measured.
The results are shown in Table 1 (the column of “tan δ (0 ° C.)” in Table 1). The results were expressed as an index with tan δ (0 ° C.) of the standard example as 100. The larger the index, the larger the tan δ (0 ° C.), and the better the wet grip performance when made into a tire.

<Tan δ (60 ° C.)>
Instead of measuring at a temperature of 0 ° C., tan δ (60 ° C.) of a vulcanized rubber test piece was measured according to the same procedure as that of tan δ (0 ° C.) described above except that the measurement was performed at a temperature of 60 ° C.
The results (reciprocal of tan δ (60 ° C.)) are shown in Table 1 (the column of “tan δ (60 ° C.)” in Table 1). The results were expressed as an index with the reciprocal of tan δ (60 ° C.) of the standard example as 100. The larger the index, the smaller the tan δ (60 ° C.), and the lower the heat build-up when the tire is made.

<Abrasion resistance>
The vulcanized rubber test piece was subjected to an applied force of 4.0 kg / cm ³ (= 39 N), a slip rate of 30%, and wear in accordance with JIS K6264-2: 2005 using a Lambourn abrasion tester (Iwamoto Seisakusho). A wear test was conducted at a test temperature of room temperature for 4 minutes, and the wear mass was measured. And the index was calculated as follows. The results are shown in Table 1. The larger the index, the less the amount of wear and the better the wear resistance.
Index = (Abrasion mass of standard specimen / Abrasion mass of each example) × 100

Details of each component in Table 1 are as follows.
-Natural rubber: TSR20 (natural rubber, Tg: -62 ° C)
Comparative conjugated diene polymer: NIPOL BR1220 (unmodified BR, manufactured by Nippon Zeon)
-Modified conjugated diene polymer: Modified conjugated diene polymer synthesized as described above-Carbon black: Show black N339 (manufactured by Cabot Japan)
Silica: ZEOSIL 1165MP (CTAB adsorption specific surface area: 159 m ² / g, manufactured by Rhodia)
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide, manufactured by Evonik Degussa)
Aroma oil: Extract No. 4 S (manufactured by Showa Shell Sekiyu KK)
Specific cured product: Specific cured product synthesized as described aboveAromatic modified terpene resin: YS resin TO-125 (softening point: 125 ± 5 ° C., manufactured by Yasuhara Chemical Co., Ltd.)
-Thermally expandable microcapsules: Microsphere F100 (manufactured by Matsumoto Yushi Co., Ltd.)
・ Sulfur: Fine powder sulfur with Jinhua seal oil (sulfur content 95.24 mass%, manufactured by Tsurumi Chemical Co., Ltd.)
・ Stearic acid: Beads stearic acid (manufactured by NOF Corporation)
・ Zinc flower: 3 types of zinc oxide
・ Vulcanization accelerator 1: Noxeller CZ-G (Ouchi Shinsei Kagaku Kogyo Co., Ltd.)
・ Vulcanization accelerator 2: Soxinol DG (Sumitomo Chemical Co., Ltd.)

  As can be seen from Table 1, the Examples of the present application in which the modified conjugated diene polymer and the specific cured product were used together exhibited excellent performance on ice, wet grip performance, low heat build-up, and wear resistance. Among them, Examples 1, 2, and 4 containing the specific aromatic modified terpene resin showed better wet grip performance. Among them, Examples 1 and 2 in which the ratio of the content of silica in the tire rubber composition to the content of the modified conjugated diene polymer in the tire rubber composition was 80% by mass or more were more excellent. The performance on ice and wet grip performance were shown. Among them, Example 1 in which the ratio of the content of silica in the tire rubber composition to the content of the modified conjugated diene polymer in the tire rubber composition is 120% by mass or less is more excellent in resistance to resistance. Abrasion was shown.

  On the other hand, standard examples and comparative examples 1 to 5 in which the modified conjugated diene polymer and the specific cured product are not used in combination, and the modified conjugated diene polymer and the specific cured product are used in combination, but the silica content is diene based. In Comparative Example 6, which is less than 20 parts by mass with respect to 100 parts by mass of rubber, at least any of the performance on ice, the wet grip performance, the low heat generation property, and the wear resistance was insufficient.

1 Bead part 2 Side wall part 3 Tire tread part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Rim cushion

Claims (5)

Contains a diene rubber, silica, and a cured product,
The content of the silica is 20 to 100 parts by mass with respect to 100 parts by mass of the diene rubber, and the content of the cured product is 0.3 to 30 parts by mass with respect to 100 parts by mass of the diene rubber. ,
The diene rubber contains natural rubber and a modified conjugated diene polymer, and the content of the natural rubber in the diene rubber is 30 to 90% by mass, and the modified conjugate in the diene rubber The diene polymer content is 10 to 70% by mass,
The modified conjugated diene polymer is obtained by modifying the active terminal of a conjugated diene polymer having a cis-1,4-bond content of 75 mol% or more with at least a hydrocarbyloxysilane compound. And
A rubber composition for tires, wherein the cured product is a cured product obtained by curing a crosslinkable oligomer or polymer that is incompatible with the diene rubber, and the cured product has a JIS A hardness of 3 to 45.   The rubber composition for a tire according to claim 1, wherein the cured product is a particulate material having an average particle diameter of 5 to 250 µm.   The rubber composition for a tire according to claim 1 or 2, wherein the crosslinkable oligomer or polymer is a polyether-based or siloxane-based polymer or copolymer and has a silane functional group. Furthermore, it contains an aromatic modified terpene resin having a softening point of 60 to 150 ° C. and a thermally expandable microcapsule,
The content of the aromatic modified terpene resin is 2 to 20 parts by mass with respect to 100 parts by mass of the diene rubber, and the content of the thermally expandable microcapsule is 0.00 with respect to 100 parts by mass of the diene rubber. The rubber composition for tires according to any one of claims 1 to 3, which is 5 to 20 parts by mass.   A pneumatic tire using the tire rubber composition according to any one of claims 1 to 4.