WO2011052027A1 - Pneumatic tire - Google Patents

Abstract

A pneumatic tire which is characterized by using a rubber composition that is obtained by blending 5-50 parts by mass of a low-molecular-weight modified conjugated diene polymer having a weight average molecular weight before modification of from 2.0 × 10³ to 15 × 10⁴ and 20-200 parts by mass of a reinforcing filler per 100 parts by mass of a rubber matrix containing a high-molecular-weight modified conjugated diene polymer having a weight average molecular weight before modification of more than 15 × 10⁴ but not more than 200 × 10⁴, said rubber composition having the rubber matrix after vulcanization to contain bubbles at a bubble fraction of 5-50% by volume.  In particular, a pneumatic winter tire using the rubber composition in a tread.  The pneumatic winter tire has achieved an improved on-ice performance without deteriorating wet steering stability and dry steering stability.

Description

Pneumatic tire

The present invention relates to a pneumatic tire using a rubber composition for a tread, particularly for winter, which can improve performance on ice without deteriorating steering stability performance on a wet road surface and steering stability performance on a dry road surface of the pneumatic tire. Related to pneumatic tires.

Conventional winter pneumatic tires have a low glass transition point (Tg) in order to improve performance on ice, and low temperature (here, low temperature is a temperature during running on ice, which is about −20 to 0 ° C.). ) Is often set to a low elastic modulus. However, since the elastic modulus at high temperatures tends to decrease when the elastic modulus at low temperature is generally lowered, the conventional winter pneumatic tires are referred to as “driving stability” (hereinafter referred to as “dry steering stability”). ) Is low, and the steering stability performance on the wet road surface (hereinafter referred to as “wet steering stability performance”) was not sufficient.

On the other hand, in Patent Document 1, a rubber composition is obtained by blending a foaming agent with a rubber matrix and having a specific range of bubble ratios after vulcanization and dynamic elastic moduli at 0 ° C. and 60 ° C. There has been proposed a winter pneumatic tire (studless tire) which is used for a tread rubber of a tire and which uses a modified conjugated diene polymer as a rubber matrix of the rubber composition. In this proposal, a certain degree of performance on ice could be achieved by using a specific modified conjugated diene polymer.
However, it is required to further improve the performance on ice in the winter pneumatic tire.

JP2004-238619

The present invention is a pneumatic tire using a rubber composition for a tread that can improve the performance on ice without lowering the wet steering stability performance and dry steering stability performance of a winter pneumatic tire under such circumstances, In particular, an object is to provide a winter pneumatic tire.
As a result of intensive research to achieve the above object, the present inventors have found that a rubber composition used for a tread of a winter pneumatic tire has a high molecular weight modified conjugated diene polymer and a low molecular weight modified conjugated diene polymer. It has been found that the above-mentioned problems can be achieved by blending. The present invention has been completed based on such findings.

That is, the present invention
[1] The weight average molecular weight before modification is 2 with respect to 100 parts by mass of the rubber matrix containing a high molecular weight modified conjugated diene polymer having a weight average molecular weight of more than 15 × 10 ⁴ and 200 × 10 ⁴ or less before modification. A rubber composition comprising 5 to 50 parts by mass of a low molecular weight modified conjugated diene polymer of 0 × 10 ³ to 15 × 10 ⁴ and 20 to 200 parts by mass of a reinforcing filler, after vulcanization A pneumatic tire using a rubber composition having 5 to 50% by volume of air bubbles in the rubber matrix;
[2] The pneumatic tire according to [1], further including 3 to 30 parts by mass of fine particles having an average major axis of 5 to 1000 μm with respect to 100 parts by mass of the rubber matrix, and [3] The rubber composition as a tread. The winter pneumatic tire used, wherein the tread has a bubble ratio of 5 to 50% by volume in a rubber matrix, and a hole formed by detaching the fine particles from a surface layer of the tread It is a pneumatic tire as described in said [2] which has.

According to the present invention, a pneumatic tire using a rubber composition that can improve the performance on ice without lowering the wet steering stability performance and the dry steering stability performance of the pneumatic tire, particularly a winter pneumatic tire. Can be provided.

The rubber composition used in the pneumatic tire of the present invention has 100 parts by mass of a rubber matrix containing a high molecular weight modified conjugated diene polymer having a weight average molecular weight of more than 15 × 10 ⁴ and not more than 200 × 10 ⁴ before modification. On the other hand, 5 to 50 parts by mass of a low molecular weight modified conjugated diene polymer having a weight average molecular weight of 2.0 × 10 ³ to 15 × 10 ⁴ before modification and 20 to 200 parts by mass of a reinforcing filler are blended. A rubber composition comprising 5 to 50% by volume of air bubbles in a rubber matrix after vulcanization.
Here, to limit the weight average molecular weight prior to modification of high molecular weight modified conjugated diene polymer 15 × 10 ⁴ to exceed 200 × 10 ⁴ or less, the wear resistance and fracture If it is 15 × 10 ⁴ or less This is because the properties deteriorate, and when it exceeds 200 × 10 ⁴ , the workability of the rubber composition is lowered. From these viewpoints, the weight average molecular weight of the high molecular weight modified conjugated diene polymer before modification is preferably 20 × 10 ⁴ to 200 × 10 ⁴ , and more preferably 20 × 10 ⁴ to 150 × 10 ^4. 20 × 10 ⁴ to 120 × 10 ⁴ is more preferable.
Also, to limit the weight average molecular weight prior to modification of low molecular weight modified conjugated diene-based polymer and ^{2.0 × 10 3 ~ 15 × 10} 4 is, 2.0 × 10 dynamically is less than ³ at a high temperature This is because the shear storage modulus G ′ decreases and the dynamic loss tangent tan δ increases, and if it exceeds 15 × 10 ⁴ , the workability decreases. From these viewpoints, the weight average molecular weight of the low molecular weight modified conjugated diene polymer before modification is preferably 5.0 × 10 ³ to 12 × 10 ⁴ , and is preferably 5.0 × 10 ³ to 10 × 10 ⁴ . It is particularly preferred.

The amount of the low molecular weight modified conjugated diene polymer is limited to 5 to 50 parts by mass with respect to 100 parts by mass of the rubber matrix. This is because when the amount exceeds 50 parts by mass, the wear resistance and the fracture resistance are deteriorated. From these viewpoints, the blending amount of the low molecular weight modified conjugated diene polymer is preferably 5 to 45 parts by mass, more preferably 10 to 40 parts by mass with respect to 100 parts by mass of the rubber matrix. 30 parts by mass is particularly preferable.
Further, the rubber composition used in the pneumatic tire of the present invention is characterized in that the vulcanized rubber matrix has 5 to 50% by volume of air bubbles in the rubber matrix, which will be described later. .

The rubber composition used for the pneumatic tire according to the present invention includes the above-mentioned low molecular weight modified conjugated diene polymer bound aromatic vinyl content (X) (%) and conjugated diene vinyl bond content (Y) (%). However, it is preferable that X + (Y / 2) <25 is satisfied. If {X + (Y / 2)} is less than 25, the performance on ice is improved.
For the same reason, the bound aromatic vinyl content (X ′) (%) of the high molecular weight modified conjugated diene polymer and the vinyl bond content (Y ′) (%) of the conjugated diene are X ′ + (Y It is preferable to satisfy '/ 2) <25.

In the rubber composition used for the pneumatic tire of the present invention, the low molecular weight modified conjugated diene polymer is at least one selected from the group consisting of a tin-containing functional group, a silicon-containing functional group, and a nitrogen-containing functional group. It preferably contains a functional group. The high molecular weight modified conjugated diene polymer preferably contains at least one functional group selected from the group consisting of a tin-containing functional group, a silicon-containing functional group, and a nitrogen-containing functional group.
This is because these functional groups are rich in reactivity with the reinforcing filler and improve the reinforcing property of the rubber composition.
In particular, a tin-containing functional group is preferable because it is highly reactive with carbon black, a silicon-containing functional group is preferable because it is highly reactive with silica, and a nitrogen-containing functional group is highly reactive with both carbon black and silica. Therefore, it is preferable.

Examples of tin-containing functional groups include tin halide compound residues, such as triphenyltin chloride, tributyltin chloride, triisopropyltin chloride, trihexyltin chloride, trioctyltin chloride, diphenyltin dichloride, dibutyltin dichloride, dihexyltin. Preference is given to residues which are produced by leaving one or more chlorine atoms from a tin chloride compound selected from the group consisting of dichloride, dioctyltin dichloride, phenyltin trichloride, butyltin trichloride, octyltin trichloride and tin tetrachloride.

Examples of the silicon-containing functional group include a residue formed by leaving one or more of —OR ^{3 of} a hydrocarbyloxysilane compound represented by the following general formula (1) and a partial condensate thereof.

In the formula, A is an isocyanate group, a thioisocyanate group, an imine residue, an amide group, a primary amino group, an onium salt residue of a primary amine, a cyclic secondary amino group, an onium salt residue of a cyclic secondary amine, Of onium salt residue, isocyanuric acid triester residue, cyclic tertiary amino group, acyclic tertiary amino group, nitrile group, pyridine residue, cyclic tertiary amine of acyclic secondary amino group and acyclic secondary amine Onium salt residue, onium salt residue of acyclic tertiary amine, epoxy group, thioepoxy group, keto group, thioketo group, aldehyde group, thioaldehyde group, carboxylic acid ester residue, thiocarboxylic acid ester residue, carboxylic acid anhydride Residue, carboxylic acid halide residue, carbonic acid dihydrocarbyl ester residue, sulfide group, multisulfide group, hydroxy group, thiol group, allyl The group, monovalent group having at least one functional group selected from a sulfonyl group and sulfinyl group, R ¹ is a single bond or a divalent inactive hydrocarbon group, R ² and R ³ having the benzyl Sn bond, Each independently represents 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, and there are a plurality of OR ³ In this case, the plurality of OR ³ may be the same or different. Of the above, the primary amino group is preferably protected by an alkylsilyl group (for example, a methylsilyl group or an ethylsilyl group) or the like until after the modification reaction.

Preferred examples of the divalent inert hydrocarbon group in R ¹ include alkylene groups having 1 to 20 carbon atoms. The alkylene group may be linear, branched, or cyclic, but a linear one is particularly preferable. 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. Here, the alkyl group and alkenyl group may be linear, branched or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, Isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, decyl, dodecyl, cyclopentyl, cyclohexyl, vinyl, propenyl, allyl, hexenyl, octenyl , Cyclopentenyl group, cyclohexenyl group and the like.
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. Further, 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.

As the nitrogen-containing functional group, among the residues formed by leaving one or more of —OR ^{3 of the} hydrocarbyloxysilane compound represented by the general formula (1) and its partial condensate, A is an isocyanate group. Thioisocyanate group, imine residue, amide group, primary amino group, onium salt residue of primary amine, cyclic secondary amino group, onium salt residue of cyclic secondary amine, acyclic secondary amino group and non-cyclic Cyclic secondary amine onium salt residue, isocyanuric acid triester residue, cyclic tertiary amino group, acyclic tertiary amino group, nitrile group, pyridine residue, cyclic tertiary amine onium salt residue, acyclic primary Examples thereof include nitrogen-containing hydrocarbyloxysilane compound residues which are onium salt residues of triamines.

Of the nitrogen-containing hydrocarbyloxysilane compounds represented by the general formula (1), N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1- Propanamine, 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 trimethoxysilanes corresponding to these triethoxysilyl compounds Preferred examples of such compounds include methyl compounds, methyldiethoxysilyl compounds, ethyldiethoxysilyl compounds, methyldimethoxysilyl compounds, and ethyldimethoxysilyl compounds. Among these, N- (1-methylpropylidene) -3 is particularly preferable. -(Triethoxysilyl) -1-propanamine and N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine are preferred.

Other imine residue (amidine group) -containing compounds include 1- [3- (triethoxysilyl) propyl] -4,5-dihydroimidazole, 1- [3- (trimethoxysilyl) propyl] -4. , 5-dihydroimidazole, 3- [10- (triethoxysilyl) decyl] -4-oxazoline, among which 3- (1-hexamethyleneimino) propyl (triethoxy) silane, (1-hexamethyleneimino) methyl (trimethoxy) silane, 1- [3- (triethoxysilyl) propyl] -4,5-dihydroimidazole and 1- [3- (trimethoxysilyl) propyl] -4,5- A preferred example is 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, among which N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole is preferable.

Among the nitrogen-containing hydrocarbyloxysilane compounds represented by the general formula (1), the isocyanate group-containing compounds include 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, and 3-isocyanatopropyl. Examples thereof include methyldiethoxysilane and 3-isocyanatopropyltriisopropoxysilane. Among these, 3-isocyanatopropyltriethoxysilane is preferable.

Among the nitrogen-containing hydrocarbyloxysilane compounds represented by the general formula (1), the cyclic tertiary amino group-containing compounds include 3- (1-hexamethyleneimino) propyl (triethoxy) silane, 3- (1-hexamethylene). Imino) 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) silane, 3- (1- Heptamethyleneimino) propyl (triethoxy) silane, 3- (1-hexamethyleneimino) propyl (diethoxy) methylsilane, 3- (1-hexamethyleneimino) can be preferably exemplified propyl (diethoxy) ethylsilane. Particularly preferred are 3- (1-hexamethyleneimino) propyl (triethoxy) silane and (1-hexamethyleneimino) methyl (trimethoxy) silane. Furthermore, other hydrocarbyloxysilane compounds include 2- (trimethoxysilylethyl) pyridine, 2- (triethoxysilylethyl) pyridine, 4-ethylpyridine and the like.

Among the nitrogen-containing hydrocarbyloxysilane compounds represented by the general formula (1), 3-dimethylaminopropyl (triethoxy) silane, 3-dimethylaminopropyl (trimethoxy) silane are used as the acyclic tertiary amino group-containing hydrocarbyloxysilane compounds. 3-diethylaminopropyl (triethoxy) silane, 3-diethylaminopropyl (trimethoxy) silane, 2-dimethylaminoethyl (triethoxy) silane, 2-dimethylaminoethyl (trimethoxy) silane, 3-dimethylaminopropyl (diethoxy) methylsilane, 3 -Dibutylaminopropyl (triethoxy) silane and the like, among which 3-diethylaminopropyl (triethoxy) silane and 3-dimethylaminopropyl (triethoxy) ) Silanes are preferred.
Further, examples of the nitrogen-containing hydrocarbyloxysilane compound represented by the general formula (1) include 2- (trimethoxysilylethyl) pyridine, 2- (triethoxysilylethyl) pyridine, 2-cyanoethyltriethoxysilane and the like. It is done.

As the nitrogen-containing functional group, among the residues formed by leaving one or more of —OR ^{3 of the} hydrocarbyloxysilane compound represented by the above general formula (1) and its partial condensate, the following general formula ( The monovalent functional group represented by 2) or the divalent functional group represented by the following general formula (3) is particularly preferred. This is because the primary amino group of the general formula (2) or the general formula (3) particularly improves the reinforcing properties of both carbon black and silica.

In the formula, R ⁴ and R ⁶ are each independently —OR, —OH or an alkyl group having 1 to 20 carbon atoms, R ⁵ is an alkyl group having 1 to 20 carbon atoms, and R is a sulfur atom, oxygen atom And a hydrocarbyl group having 1 to 20 carbon atoms which may have a nitrogen atom and / or a halogen atom.

Here, R ⁷ and R ⁹ are each independently —OR, —OH or an alkyl group having 1 to 20 carbon atoms; R ⁸ and R ¹⁰ are each independently an alkyl group having 1 to 20 carbon atoms; Is a hydrocarbyl group having 1 to 20 carbon atoms which may have a sulfur atom, oxygen atom, nitrogen atom and / or halogen atom, M is Si, Ti, Sn, Bi or Zr, and R ¹¹ is- OH, hydrocarbyl group having 1 to 30 carbon atoms, hydrocarbyl carboxyl group having 2 to 30 carbon atoms, 1,3-dicarbonyl-containing group having 5 to 20 carbon atoms, hydrocarbyloxy group having 1 to 20 carbon atoms, and 1 carbon atom A group selected from the group consisting of a siloxy group trisubstituted by a hydrocarbyl group having ˜20 and / or a hydrocarbyloxy group having 1-20 carbon atoms, and a plurality of R ¹¹ may be the same or different, and k is { (M Number) is -2}, n is an integer of 0 or 1]

As —OR of R ⁴ , R ⁶ , R ⁷ and R ^{9 in} the general formulas (2) and (3), methoxy group, ethoxy group, propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, sec -Butoxy group, tert-butoxy group, pentyloxy group, allyloxy group, phenoxy group, benzyloxy group and the like, and these functional groups have a sulfur atom, an oxygen atom, a nitrogen atom and / or a halogen atom. May be. The sulfur atom may be contained in R as, for example, —SH, —S _X — (X is an integer of 1 to 5), or an epithio group. The oxygen atom may be contained in R as —OH, —O—, an epoxy group, an acyl group, or a carboxyl group. Nitrogen atoms include amino groups (primary amino groups, secondary amino groups, or acyclic or cyclic tertiary amino groups), imino groups, amidine groups, isocyanate groups, N-hydroxy groups, N-oxide groups, nitrile groups, It may be contained in R as an imine residue.

Examples of the alkyl group having 1 to 20 carbon atoms of R ⁴ , R ⁶ , R ⁷ and R ⁹ include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, Examples thereof include a tert-butyl group, a pentyl group, a hexyl group, and an octyl group.
The halogen atom which may be contained in R may be any of fluorine, chlorine, bromine and iodine, but chlorine or bromine is preferred.

Examples of the alkylene group having 1 to 20 carbon atoms of R ⁵ , R ⁸ and R ¹⁰ include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1, 4-diyl group, butane-1,3-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, Nonane-1,9-diyl group, decane-1,10-diyl group and the like can be mentioned.
In general, R ⁷ and R ⁹ are the same, and R ⁸ and R ¹⁰ are the same. This is because the divalent functional group represented by the above general formula (3) is formed by condensing two polymer chains having the same monovalent functional group represented by the above general formula (2).
The primary amino group of the general formula (2) or (3) is protected by an alkylsilyl group (for example, a methylsilyl group or an ethylsilyl group) until the end of the modification reaction, as in the case of the general formula (1). It is preferable that

The residue from which lithium is released from the lithium amide compound described later as an initiator for anionic polymerization is also preferable as the nitrogen-containing functional group contained in the high molecular weight modified conjugated diene polymer or the low molecular weight modified conjugated diene polymer.

Further, among the at least one functional group selected from the group consisting of a tin-containing functional group, a silicon-containing functional group, and a nitrogen-containing functional group contained in the high molecular weight modified conjugated diene polymer, the above general formula (2) The monovalent functional group represented or the divalent functional group represented by the general formula (3) is preferable.
On the other hand, among the at least one functional group selected from the group consisting of a tin-containing functional group, a silicon-containing functional group, and a nitrogen-containing functional group contained in the low molecular weight modified conjugated diene polymer, the above general formula (2) It may be a monovalent functional group represented or a functional group other than the divalent functional group represented by the general formula (3).
Since the monovalent functional group represented by the general formula (2) or the divalent functional group represented by the general formula (3) has high reactivity with the reinforcing filler, a high molecular weight modified conjugated diene polymer. This is because the rubber composition further improves the reinforcing property due to the reaction between the reinforcing filler and the reinforcing filler, and further improves the dry steering stability performance, wear resistance and fracture resistance.

In the rubber composition used in the pneumatic tire of the present invention, the low molecular weight modified conjugated diene polymer is preferably low molecular weight modified polybutadiene and / or low molecular weight modified polyisoprene, and low molecular weight modified polybutadiene is particularly preferable. . The high molecular weight modified conjugated diene polymer is preferably modified polybutadiene rubber and / or modified polyisoprene rubber, and particularly preferably modified polybutadiene rubber. This is because the glass transition point (Tg) of the low molecular weight modified conjugated diene polymer and the high molecular weight modified conjugated diene polymer is lowered to improve the performance on ice.

Examples of the conjugated diene monomer used in the low molecular weight modified conjugated diene polymer and the high molecular weight modified conjugated diene polymer include, for example, 1.3-butadiene, isoprene, 1.3-pentadiene, 2,3-dimethyl-1 , 3-butadiene, 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 preferred.
Examples of the aromatic vinyl monomer used in the low molecular weight modified conjugated diene polymer and the high molecular weight modified conjugated diene polymer include styrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, and ethyl. Examples thereof include vinylbenzene, divinylbenzene, 4-cyclohexylstyrene, 2,4,6-trimethylstyrene and the like. These may be used alone or in combination of two or more, but among these, styrene is particularly preferred.

The polymerization reaction system for obtaining the low molecular weight modified conjugated diene polymer and the high molecular weight modified conjugated diene polymer used in the rubber composition used in the pneumatic tire of the present invention will be described. In order to react the active end of the conjugated diene polymer with the modifier and introduce a tin-containing functional group, silicon-containing functional group or nitrogen-containing functional group at the active end of the conjugated diene polymer, The coalescence is preferably such that at least 10% of the polymer chains have living or pseudo-living properties. Examples of such a polymerization reaction having a living property include anionic polymerization and coordination anionic polymerization. Anionic polymerization is preferable in that a wide range of modification is possible.

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

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

On the other hand, examples of the lithium amide compound include lithium hexamethylene imide, lithium pyrrolidide, lithium piperide, lithium heptamethylene imide, lithium dodecamethylene imide, lithium dimethyl amide, lithium diethyl amide, lithium dibutyl amide, lithium dipropyl amide, and lithium disulfide. Heptylamide, lithium dihexylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium-N-methylpiverazide, lithium ethylpropylamide, lithium ethylbutyramide, lithium ethylbenzylamide, lithium methylphenethylamide, etc. Is mentioned. Among these, from the viewpoint of the interaction effect on carbon black and the ability of initiating polymerization, cyclic lithium amides such as lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene imide, and lithium dodecamethylene imide are preferable. In particular, lithium hexamethylene imide and lithium pyrrolidide are suitable.

These lithium amide compounds are generally prepared in advance from a secondary amine and a lithium compound for polymerization, but can also be prepared in-situ. The amount of the polymerization initiator used is preferably selected in the range of 0.2 to 20 mmol per 100 g of monomer.

There is no restriction | limiting in particular as a method of manufacturing a conjugated diene polymer by anionic polymerization using the said lithium compound as a polymerization initiator, A conventionally well-known method can be used.
Specifically, in an organic solvent inert to the reaction, for example, a hydrocarbon solvent such as an aliphatic, alicyclic, or aromatic hydrocarbon compound, a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl are used. The monomer is anionically polymerized with the lithium compound as a polymerization initiator in the presence of a randomizer to be used, if desired, to obtain a conjugated diene polymer having a target active end.
In addition, when a lithium compound is used as a polymerization initiator, not only a conjugated diene polymer having an active terminal but also a conjugated compound having an active terminal compared to the case of using a catalyst containing a lanthanum series rare earth element compound described above. A diene-aromatic vinyl copolymer 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-2 -Butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene and the like. These may be used alone or in combination of two or more.
The monomer concentration in the solvent is preferably 5 to 50% by mass, more preferably 10 to 30% by mass. When copolymerization is performed using a conjugated diene monomer and an aromatic vinyl monomer, the content of the aromatic vinyl monomer 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 polymer, for example, the vinyl bond in the butadiene polymer, the vinyl bond in the butadiene moiety in the butadiene-styrene copolymer, and the vinyl bond in the isoprene polymer. Or a compound having an action of controlling the composition distribution of the monomer unit in the conjugated diene / aromatic vinyl copolymer, for example, randomizing the butadiene unit or the styrene unit in the butadiene-styrene copolymer. The randomizer is not particularly limited, and an arbitrary one can be appropriately selected from known compounds generally used as a conventional randomizer.

Specific examples of the randomizer include dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, oxolanyl propane oligomers [especially those containing 2,2-bis (2-tetrahydrofuryl) -propane, etc.], Mention may be made of ethers such as triethylamine, pyridine, N-methylmorpholine, N, N, N ′, N′-tetramethylethylenediamine, 1,2-dipiperidinoethane, and tertiary amines. Further, potassium salts such as potassium t-amylate and potassium t-butoxide, and sodium salts such as sodium t-amylate can also be used.

These randomizers may be used alone or in combination of two or more. The amount used is preferably selected in the range of 0.01 to 1000 molar equivalents per mole of lithium compound.

The temperature in this polymerization reaction is preferably selected in the range of 0 to 150 ° C., more preferably 20 to 130 ° C. The polymerization reaction can be carried out under generated pressure, but it is usually desirable to operate at a pressure sufficient to keep the monomer in a substantially liquid phase. That is, the pressure depends on the particular material being polymerized, the polymerization medium used and the polymerization temperature, but higher pressures can be used if desired, such pressure being a gas that is inert with respect to the polymerization reaction. Can be obtained by an appropriate method such as pressurizing.

In the above-mentioned anionic polymerization, all raw materials involved in the polymerization such as polymerization initiator, solvent, monomer, etc. should be used after removing reaction inhibitor such as water, oxygen, carbon dioxide, and protic compound. desirable.
The polymerization reaction may be carried out either batchwise or continuously.
In this way, a conjugated diene polymer having an active end is obtained.

In the present invention, the conjugated diene polymer having an active terminal obtained as described above is incorporated with the above-described modifier capable of introducing a tin-containing functional group, a silicon-containing functional group and a nitrogen-containing functional group. The stoichiometric amount or an excess thereof is preferably added to the active end of the diene polymer and reacted with the active end bonded to the polymer. The modification reaction may be performed under the same temperature and pressure conditions as the polymerization reaction.

The amount of the above-mentioned modifier used is usually 0.2 to 10 equivalents, preferably 0.5 to 5.0 equivalents, based on the functional group capable of modifying reaction per 1 g atomic equivalent of lithium atom. If the amount is less than 2 equivalents, the rebound resilience and low heat build-up effect of the vulcanized rubber is inferior. On the other hand, if the amount exceeds 10 equivalents, unreacted substances increase and odor is generated, the vulcanization speed is increased, The effects of rebound resilience and low heat build-up are reduced, which is not preferable.

Next, as the modifier capable of introducing the divalent functional group represented by the general formula (3), the hydrocarbyloxysilane compound having the protected primary amino group is preferably used. After performing the first stage modification reaction with the agent, it is necessary to perform the second stage modification reaction in the presence of a condensation accelerator composed of a metal compound of Si, Ti, Sn, Bi, Zr or Al. However, water needs to be present during the second-stage denaturation reaction or in subsequent steps.

More specifically, as the above condensation accelerator, divalent tin dicarboxylic acid {particularly, bis (hydrocarbylcarboxylic acid) salt} or tetravalent dihydrocarbyltin dicarboxylic acid salt {bis (hydrocarbylcarboxylic acid) } Salt), bis (1,3-diketonate), alkoxy halide, monocarboxylate hydroxide, alkoxy (trihydrocarbylsiloxide), alkoxy (dihydrocarbylalkoxysiloxide), bis (trihydrocarbylsiloxide), Bis (dihydrocarbylalkoxysiloxide) or the like can be suitably used. The hydrocarbyl group bonded to tin preferably has 4 or more carbon atoms, and particularly preferably has 4 to 8 carbon atoms.
Examples of the titanium compound include tetravalent titanium tetraalkoxide, dialkoxybis (1,3-diketonate), tetrakis (trihydrocarboxide), and tetrakis (trihydrocarboxide) is particularly preferably used. .

Examples of the bismuth compounds include bismuth carboxylates {particularly hydrocarbyl carboxylates}, and examples of the zirconium compounds include zirconium alkoxides and zirconium carboxylates {particularly hydrocarbyl carboxylates}. be able to.
Examples of the aluminum compound include aluminum alkoxide and aluminum carboxylate {particularly hydrocarbyl carboxylate}. Examples of the silicon compound include silicon alkoxide and silicon carboxylate {particularly hydrocarbyl. Carboxylate}.

Specific examples of the titanium compound include tetrakis (2-ethyl-1,3-hexanediolato) titanium, tetrakis (2-methyl-1,3-hexanediolato) titanium, tetrakis (2-propyl-1, 3-hexanediolato) titanium, tetrakis (2-butyl-1,3-hexanediolato) titanium, tetrakis (1,3-hexanediolato) titanium, tetrakis (1,3-pentanediolato) titanium, tetrakis ( 2-methyl-1,3-pentanediolato) titanium, tetrakis (2-ethyl-1,3-pentanediolato) titanium, tetrakis (2-propyl-1,3-pentanediolato) titanium, tetrakis (2- Butyl-1,3-pentanediolato) titanium, tetrakis (1,3-heptanediolato) titanium, tetrakis (2-methyl) 1,3-heptanediolato) titanium, tetrakis (2-ethyl-1,3-heptanediolato) titanium, tetrakis (2-propyl-1,3-heptanediolato) titanium, tetrakis (2-butyl-1,3-heptanediolato) titanium, Tetrakis (2-ethylhexoxy) titanium, tetramethoxy titanium, tetraethoxy titanium, tetra-n-propoxy titanium, tetraisopropoxy titanium, tetra-n-butoxy titanium, tetra-n-butoxy titanium oligomer, tetraisobutoxy titanium, tetra- sec-butoxytitanium, tetra-tert-butoxytitanium, bis (oleate) bis (2-ethylhexanoate) titanium, titanium dipropoxybis (triethanolaminate), titanium dibutoxybis (triethanolaminate) ), Titanium tributoxy systemate, titanium tripropoxy systemate, titanium tripropoxyacetylacetonate, titanium dipropoxybis (acetylacetonate), titanium tripropoxy (ethylacetoacetate), titaniumpropoxyacetylacetonatebis (ethylacetoacetate) ), Titanium tributoxyacetylacetonate, titanium dibutoxybis (acetylacetonate), titanium tributoxyethylacetoacetate, titaniumbutoxyacetylacetonatebis (ethylacetoacetate), titanium tetrakis (acetylacetonate), titanium diacetylacetonate Bis (ethyl acetoacetate), bis (2-ethylhexanoate) titanium oxide, bis (laurate) titanium oxide, bis (na Phthalate) titanium oxide, bis (stearate) titanium oxide, bis (oleate) titanium oxide, bis (linoleate) titanium oxide, tetrakis (2-ethylhexanoate) titanium, tetrakis (laurate) titanium, tetrakis (naphthenate) titanium, Tetrakis (stearate) titanium, Tetrakis (oleate) titanium, Tetrakis (linoleate) titanium, Titanium di-n-butoxide (bis-2,4-pentandionate), Titanium oxide bis (stearate), Titanium oxide bis (tetramethyl) Heptane dionate), titanium oxide bis (pentanedionate), titanium tetra (lactate) and the like. Of these, tetrakis (2-ethyl-1,3-hexanediolato) titanium, tetrakis (2-ethylhexoxy) titanium, and titanium di-n-butoxide (bis-2,4-pentanedionate) are preferable.

As the tin compound, specifically, stannous 2-ethylhexanoate {[CH ₃ (CH ₂ ) ₃ CH (C ₂ H ₅ ) CO ₂ ] ₂ Sn (divalent)}, octanoic acid Examples include stannous, stannous neodecanoate, stannous isooctanoate, stannous isodecanoate, 2,2-dimethyldecanoic acid, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctanoate, and dimethyltin dilaurate. It is done.
Examples of bismuth compounds include tris (2-ethylhexanoate) bismuth, tris (laurate) bismuth, tris (naphthenate) bismuth, tris (stearate) bismuth, tris (oleate) bismuth, tris (linoleate) bismuth and the like. Can do.

Specific examples of the zirconium compound include tetraethoxy zirconium, tetra n-propoxy zirconium, tetra i-propoxy zirconium, tetra n-butoxy zirconium, tetra sec-butoxy zirconium, tetra tert-butoxy zirconium, tetra (2-ethyl). Hexyl) zirconium, zirconium tributoxy systemate, zirconium tributoxy acetylacetonate, zirconium dibutoxy bis (aceteracetonate), zirconium tributoxyethyl acetoacetate, zirconium butoxyacetylacetonate bis (ethyl acetoacetate), zirconium tetrakis (Acetylacetonate), zirconium diacetylacetonate bis (ethylacetoacetate), bis ( -Ethylhexanonito) zirconium oxide, bis (laurate) zirconium oxide, bis (naphthenate) zirconium oxide, bis (stearate) zirconium oxide, bis (oleate) zirconium oxide, bis (linoleate) zirconium oxide, tetrakis (2-ethyl) Hexanoate) zirconium, tetrakis (laurate) zirconium, tetrakis (naphthenate) zirconium, tetrakis (stearate) zirconium, tetrakis (oleate) zirconium, tetrakis (linoleate) zirconium and the like.

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

Water is preferably used in the form of a solution such as a simple substance or alcohol, or a dispersed micelle in a hydrocarbon solvent, and if necessary, in the reaction system 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 can also be used effectively. Accordingly, it is also preferable to use a compound that can easily release water, such as a solid having adsorbed water or a hydrate, in combination with the condensation accelerator.

The condensation accelerator and water may be added separately to the reaction system or mixed immediately before use as a mixture, but long-term storage of the mixture is not preferable because it causes decomposition of the metal compound.
In addition, water may be introduced into the reaction system as a solution of an organic solvent compatible with water such as alcohol, or water may be directly injected and dispersed in a hydrocarbon solution using various chemical engineering techniques. You may let them. Water may be added by steam stripping or the like after completion of the second stage modification reaction.
The amount of the condensation accelerator used is preferably selected so that the molar ratio of the metal of the metal compound and the proton source to the total amount of hydrocarbyloxysilyl bonds present in the system is 0.1 or more.
The number of moles of the condensation accelerator metal and water effective for the reaction is preferably 0.1 or more as a molar ratio to the total amount of hydrocarboxysilyl groups present in the reaction system. The upper limit depends on the purpose and reaction conditions, but there should be 0.5 to 3 molar equivalents of effective water based on the amount of hydrocarboxysilyl groups bound to the polymer active site before the condensation treatment. Is preferred.
The second-stage modification reaction using the condensation accelerator is preferably performed at a temperature of 20 ° C. or higher, and more preferably in the range of 30 to 120 ° C. The reaction time is more preferably in the range of 0.5 minutes to 10 hours, preferably 0.5 minutes to 5 hours, more preferably about 0.5 to 120 minutes, and 3 to 60 minutes.
The pressure of the reaction system during the second stage modification reaction is usually 0.01 to 20 MPa, preferably 0.05 to 10 MPa.

In the present invention, during this modification reaction, if desired, a known anti-aging agent or a short stop agent for the purpose of terminating the polymerization reaction, and a step after introducing a hydrocarbyloxysilane compound residue into the active site of the polymer. , Can be added. Further, after completion of the modification reaction, a condensation inhibitor such as a higher carboxylic acid ester of a polyhydric alcohol may be added to the reaction system.
After the modification treatment in this way, a conventionally known post-treatment such as desolvation such as steam stripping can be performed to obtain the desired modified polymer.

The deprotection treatment for removing the protected nitrogen atom protecting group after the completion of the two-stage denaturation reaction to produce a primary amino group is not limited to the above-described desolvation treatment using steam such as steam stripping. Conversion from the stage of the modification reaction to the free primary amino group by hydrolyzing the protecting group on the primary amino group in various ways as required in any stage from solvent removal to dry polymer. The deprotection treatment of the protected primary amino group derived from the hydrocarbyloxysilane compound can be performed.

Next, a polymerization catalyst system for coordination anion polymerization will be described. As a polymerization catalyst system for coordination anionic polymerization, a catalyst containing a lanthanum series rare earth element compound in an organic solvent is used.
As a catalyst containing a lanthanum series rare earth element compound,
(A) component: a rare earth element-containing compound having an atomic number of 57 to 71 in the periodic table, or a reaction product of these compounds with a Lewis base,
(B) component: The following general formula (4):
AlR ¹² R ¹³ R ¹⁴ (4)
(Wherein R ¹² and R ¹³ are the same or different and are a hydrocarbyl group having 1 to 10 carbon atoms or a hydrogen atom, and R ¹⁴ is a hydrocarbyl group having 1 to 10 carbon atoms, provided that R ¹⁴ is the above R ¹² or an organoaluminum compound represented by R ¹³ may be the same or different and), and component (C): at least one organic compound containing a Lewis acid, a metal halide, a complex compound of Lewis base, and an active halogen It is preferred to polymerize the conjugated diene monomer with a catalyst system comprising:

In the present invention, in addition to the above components (A) to (C), an organoaluminum oxy compound, so-called aluminoxane, may be added as a component (D) in addition to the components (A) to (C). preferable. Here, it is more preferable that the catalyst system is preliminarily prepared in the presence of the component (A), the component (B), the component (C), the component (D) and the conjugated diene monomer.

In the present invention, the component (A) of the catalyst system containing a lanthanum series rare earth element compound is a compound containing a rare earth element having an atomic number of 57 to 71 in the periodic table, or a reaction product of these compounds with a Lewis base. . Here, among the rare earth elements having atomic numbers of 57 to 71, neodymium, praseodymium, cerium, lanthanum, gadolinium, samarium, or a mixture thereof is preferable, and neodymium is particularly preferable.

The rare earth element-containing compound is preferably a salt soluble in a hydrocarbon solvent, specifically, a carboxylate, alkoxide, 1,3-diketone complex, phosphate, and phosphite of the rare earth element. Among these, carboxylates and phosphates are preferable, and carboxylates are particularly preferable.
Here, examples of the hydrocarbon solvent include saturated aliphatic hydrocarbons having 4 to 10 carbon atoms such as butane, pentane, hexane and heptane, saturated alicyclic hydrocarbons having 5 to 20 carbon atoms such as cyclopentane and cyclohexane, -Monoolefins such as butene, 2-butene, aromatic hydrocarbons such as benzene, toluene, xylene, methylene chloride, chloroform, trichloroethylene, perchloroethylene, 1,2-dichloroethane, chlorobenzene, bromobenzene, chlorotoluene, etc. A halogenated hydrocarbon is mentioned.

As the rare earth element carboxylate, the following general formula (5):
(R ¹⁵ -CO ₂ ) ₃ M ¹ (5)
(Wherein R ¹⁵ is a hydrocarbyl group having 1 to 20 carbon atoms, and M ¹ is a rare earth element having an atomic number of 57 to 71 in the periodic table). Here, R ¹⁵ may be saturated or unsaturated, is preferably an alkyl group or an alkenyl group, and may be linear, branched or cyclic. The carboxyl group is bonded to a primary, secondary or tertiary carbon atom. As the carboxylate, specifically, octanoic acid, 2-ethylhexanoic acid, oleic acid, neodecanoic acid, stearic acid, benzoic acid, naphthenic acid, versatic acid [trade names of Shell Chemical Co., Ltd. , A carboxylic acid in which a carboxyl group is bonded to a tertiary carbon atom] and the like. Among these, salts of 2-ethylhexanoic acid, neodecanoic acid, naphthenic acid, and versatic acid are preferable.

As the alkoxide of the rare earth element, the following general formula (6):
(R ¹⁶ O) ₃ M ² (6)
(Wherein R ¹⁶ is a hydrocarbyl group having 1 to 20 carbon atoms, and M ² is a rare earth element having an atomic number of 57 to 71 in the periodic table). Examples of the alkoxy group represented by R ¹⁶ O include a 2-ethyl-hexyloxy group, an oleyloxy group, a stearyloxy group, a phenoxy group, and a benzyloxy group. Of these, 2-ethyl-hexyloxy group and benzyloxy group are preferable.

Examples of the rare earth element 1,3-diketone complex include the rare earth element acetylacetone complex, benzoylacetone complex, propionitrileacetone complex, valerylacetone complex, and ethylacetylacetone complex. Among these, an acetylacetone complex and an ethylacetylacetone complex are preferable.

Examples of the rare earth element phosphate and phosphite include the rare earth element, bis (2-ethylhexyl) phosphate, bis (1-methylheptyl phosphate), bis (p-nonylphenyl) phosphate, phosphorus Bis (polyethylene glycol-p-nonylphenyl), phosphoric acid (1-methylheptyl) (2-ethylhexyl), phosphoric acid (2-ethylhexyl) (p-nonylphenyl), 2-ethylhexylphosphonic acid mono-2-ethylhexyl 2-ethylhexylphosphonic acid mono-p-nonylphenyl, bis (2-ethylhexyl) phosphinic acid, bis (1-methylheptyl) phosphinic acid, bis (p-nonylphenyl) phosphinic acid, (1-methylheptyl) (2 -Ethylhexyl) phosphinic acid, (2-ethylhexyl) (p-nonylphenyl) phos And salts with phosphoric acid and the like. Among these, the rare earth elements, bis (2-ethylhexyl) phosphate, bis (1-methylheptyl) phosphate, mono-2-ethylhexyl 2-ethylhexylphosphonate, A salt with bis (2-ethylhexyl) phosphinic acid is preferred.

Among the rare earth element-containing compounds, neodymium phosphate and neodymium carboxylate are more preferable, and in particular, neodymium branching such as neodymium 2-ethylhexanoate, neodymium neodecanoate, neodymium versatate, etc. Carboxylate is most preferred.

The component (A) may be a reaction product of the rare earth element-containing compound and a Lewis base. The reaction product has improved solubility of the rare earth element-containing compound in the solvent due to the Lewis base, and can be stably stored for a long period of time. In order to easily solubilize the rare earth element-containing compound in a solvent and to store it stably for a long period of time, the Lewis base is used in a proportion of 0 to 30 mol, preferably 1 to 10 mol, per mol of the rare earth element. Or as a mixture of the two or as a product obtained by reacting both in advance. Here, examples of the Lewis base include acetylacetone, tetrahydrofuran, pyridine, N, N-dimethylformamide, thiophene, diphenyl ether, triethylamine, an organic phosphorus compound, and a monovalent or divalent alcohol.

The rare earth element-containing compound as the component (A) described above or a reaction product of these compounds with a Lewis base can be used alone or in combination of two or more.

In the present invention, the organoaluminum compound represented by the above general formula (4) which is the component (B) of the catalyst system used for the polymerization of the terminal active polymer includes trimethylaluminum, triethylaluminum, tri-n-propylaluminum, Triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-t-butylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum; diethylaluminum hydride, di-n-propyl hydride Aluminum, di-n-butylaluminum hydride, diisobutylaluminum hydride, dihexylaluminum hydride, diisohexylaluminum hydride, dioctylaluminum hydride, hydrogenated Isooctyl aluminum, ethyl aluminum dihydride, n- propyl aluminum dihydride, include isobutyl aluminum dihydride and the like, among these, triethylaluminum, triisobutylaluminum, hydrogenated diethylaluminum, hydrogenated diisobutylaluminum are preferred. The organoaluminum compound as the component (B) described above can be used alone or in combination of two or more.

In the present invention, the component (C) of the catalyst system used for the polymerization of the terminal active polymer is at least selected from the group consisting of a Lewis acid, a complex compound of a metal halide and a Lewis base, and an organic compound containing an active halogen. It is a kind of halogen compound.

The Lewis acid has Lewis acidity and is soluble in hydrocarbons. Specifically, methyl aluminum dibromide, methyl aluminum dichloride, ethyl aluminum dibromide, ethyl aluminum dichloride, butyl aluminum dibromide, butyl aluminum dichloride, dimethyl aluminum bromide, dimethyl aluminum chloride, diethyl bromide Aluminum, diethylaluminum chloride, dibutylaluminum bromide, dibutylaluminum chloride, methylaluminum sesquibromide, methylaluminum sesquichloride, ethylaluminum sesquibromide, ethylaluminum sesquichloride, dibutyltin dichloride, aluminum tribromide, antimony trichloride, Examples include antimony pentachloride, phosphorus trichloride, phosphorus pentachloride, tin tetrachloride, and silicon tetrachloride. Among these, diethylaluminum chloride, sesquiethylaluminum chloride, ethylaluminum dichloride, diethylaluminum bromide, ethylaluminum sesquibromide, and ethylaluminum dibromide are preferable.
Alternatively, a reaction product of an alkylaluminum and a halogen such as a reaction product of triethylaluminum and bromine can be used.

The metal halide constituting the complex compound of the above metal halide and Lewis base includes beryllium chloride, beryllium bromide, beryllium iodide, magnesium chloride, magnesium bromide, magnesium iodide, calcium chloride, calcium bromide, iodine. Calcium chloride, barium chloride, barium bromide, barium iodide, zinc chloride, zinc bromide, zinc iodide, cadmium chloride, cadmium bromide, cadmium iodide, mercury chloride, mercury bromide, mercury iodide, manganese chloride, Manganese bromide, manganese iodide, rhenium chloride, rhenium bromide, rhenium iodide, copper chloride, copper iodide, silver chloride, silver bromide, silver iodide, gold chloride, gold iodide, gold bromide, etc. Of these, magnesium chloride, calcium chloride, barium chloride, manganese chloride, zinc chloride, and copper chloride are preferred. Ku, magnesium chloride, manganese chloride, zinc chloride, copper chloride being particularly preferred.

Further, as the Lewis base constituting the complex compound of the metal halide and Lewis base, a phosphorus compound, a carbonyl compound, a nitrogen compound, an ether compound, an alcohol, and the like are preferable. Specifically, tributyl phosphate, tri-2-ethylhexyl phosphate, triphenyl phosphate, tricresyl phosphate, triethylphosphine, tributylphosphine, triphenylphosphine, diethylphosphinoethane, diphenylphosphinoethane, acetylacetone, benzoylacetone , Propionitrile acetone, valeryl acetone, ethyl acetylacetone, methyl acetoacetate, ethyl acetoacetate, phenyl acetoacetate, dimethyl malonate, diethyl malonate, diphenyl malonate, acetic acid, octanoic acid, 2-ethyl-hexanoic acid, olein Acid, stearic acid, benzoic acid, naphthenic acid, versatic acid, triethylamine, N, N-dimethylacetamide, tetrahydrofuran, diphenyl ether, 2-ethyl-hexyl alcohol Examples include oleyl alcohol, stearyl alcohol, phenol, benzyl alcohol, 1-decanol, and lauryl alcohol. Among these, tri-2-ethylhexyl phosphate, tricresyl phosphate, acetylacetone, 2-ethylhexanoic acid, versatic acid, 2 -Ethylhexyl alcohol, 1-decanol, lauryl alcohol are preferred.

The above Lewis base is usually reacted at a ratio of 0.01 to 30 mol, preferably 0.5 to 10 mol, per 1 mol of the metal halide. When the reaction product with the Lewis base is used, the metal remaining in the polymer can be reduced.
Examples of the organic compound containing the active halogen include benzyl chloride.

Also, examples of the aluminoxane as component (D) include methylaluminoxane, ethylaluminoxane, propylaluminoxane, butylaluminoxane, chloroaluminoxane and the like. By adding aluminoxane as the component (D), the molecular weight distribution becomes sharp and the activity as a catalyst is improved.

The amount or composition ratio of each component of the catalyst system used in the present invention is appropriately selected according to its purpose or necessity. Of these, the component (A) is preferably used in an amount of 0.00001 to 1.0 mmol, more preferably 0.0001 to 0.5 mmol, per 100 g of 1,3-butadiene. When the amount of component (A) used is within the above range, excellent polymerization activity can be obtained, and the need for a deashing step is eliminated.
The ratio of the component (A) to the component (B) is a molar ratio, and the ratio of the component (A): component (B) is usually 1: 1 to 1: 700, preferably 1: 3 to 1: 500.
Furthermore, the ratio of the halogen in the component (A) and the component (C) is, as a molar ratio, usually 1: 0.1 to 1:30, preferably 1: 0.2 to 1:15, more preferably 1: 2.0 to 1: 5.0.
Further, the ratio of aluminum to the component (A) in the component (D) is usually 1: 1 to 700: 1, preferably 3: 1 to 500: 1 in terms of molar ratio. By making the amount of these catalysts within the range of the component ratio, it is preferable because it acts as a highly active catalyst and there is no need for a step of removing the catalyst residue.
In addition to the above components (A) to (C), the polymerization reaction may be carried out in the presence of hydrogen gas for the purpose of adjusting the molecular weight of the polymer.

As the catalyst component, in addition to the components (A), (B), (C) and the component (D) used as necessary, a conjugated diene monomer such as 1,3-butadiene may be used as necessary. A small amount, specifically, a ratio of 0 to 1000 moles per mole of the component (A) compound may be used. A conjugated diene monomer such as 1,3-butadiene as a catalyst component is not essential, but when used in combination, there is an advantage that the catalytic activity is further improved.

In the production of the catalyst, for example, the components (A) to (C) are dissolved in a solvent and, if necessary, a conjugated diene monomer such as 1,3-butadiene is reacted.
In that case, the addition order of each component is not specifically limited, Furthermore, you may add an aluminoxane as (D) component. From the viewpoint of improving the polymerization activity and shortening the polymerization initiation induction period, it is preferable that these components are mixed in advance, reacted and aged.
Here, the aging temperature is about 0 to 100 ° C., preferably 20 to 80 ° C. When the temperature is less than 0 ° C., the aging is not sufficiently performed, and when the temperature exceeds 100 ° C., the catalytic activity may be reduced or the molecular weight distribution may be broadened.
The aging time is not particularly limited, and can be ripened by contacting in the line before adding to the polymerization reaction tank. Usually, 0.5 minutes or more is sufficient, and stable for several days.

In the production of the conjugated diene polymer having terminal activity, a conjugated diene monomer alone or another conjugated diene monomer and another conjugated compound in an organic solvent using a catalyst system containing the lanthanum series rare earth element-containing compound. It can be obtained by solution polymerization of diene monomer. Here, an inert organic solvent is used as the polymerization solvent. Examples of the inert organic solvent include saturated aliphatic hydrocarbons having 4 to 10 carbon atoms such as butane, pentane, hexane and heptane, saturated alicyclic hydrocarbons having 5 to 20 carbon atoms such as cyclopentane and cyclohexane, 1- Monoolefins such as butene and 2-butene, aromatic hydrocarbons such as benzene, toluene and xylene, methylene chloride, chloroform, carbon tetrachloride, trichloroethylene, perchloroethylene, 1,2-dichloroethane, chlorobenzene, bromobenzene, chloro And halogenated hydrocarbons such as toluene.
Among these, aliphatic hydrocarbons and alicyclic hydrocarbons having 5 to 6 carbon atoms are particularly preferable. These solvents may be used alone or in a combination of two or more.
The monomer concentration in the solvent used for this coordinated anionic polymerization is preferably 5 to 50% by mass, more preferably 10 to 30% by mass.

In the present invention, the temperature in the coordination anion 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 depends on the particular material being polymerized, the polymerization medium used and the polymerization temperature, but higher pressures can be used if desired, such pressure being a gas that is inert with respect to the polymerization reaction. Can be obtained by an appropriate method such as pressurizing.

When the active terminus of the conjugated diene polymer having an active terminus obtained by the coordination anion polymerization reaction is modified, the hydrocarbyloxysilane compound is reacted in advance in the above pre-denaturation reaction step, followed by hydrolysis to produce a silanol group. And (i) an organic silane compound and the conjugated diene polymer are bonded to each other by performing an addition or substitution reaction on the active site in the vicinity of the characteristic group, and the silanol group is reinforced after the reaction. From the standpoint of smoothly promoting the modification reaction by reacting an organosilane compound having a functional group that promotes the reaction with the functional filler or (ii) the functional group that promotes the reaction between the silanol group and the reinforcing filler. preferable.

In the above-mentioned anionic polymerization and coordination anionic polymerization, all the raw materials involved in the polymerization such as polymerization initiator, solvent, monomer, and the like have removed reaction inhibitors such as water, oxygen, carbon dioxide, and protic compounds. It is desirable to use one.
The polymerization reaction may be carried out either batchwise or continuously.
In this way, a conjugated diene polymer having an active end is obtained.

In the modified conjugated diene polymer according to the present invention, the cis-1,4 bond content of the conjugated diene moiety is preferably 30% or more. It is because the low temperature characteristic of a rubber composition will deteriorate that it is less than 30%, and the performance on ice of a winter pneumatic tire will deteriorate.

The rubber matrix of the rubber composition used for the pneumatic tire of the present invention is preferably composed of 10 to 100% by mass of a high molecular weight modified conjugated diene polymer and 90 to 0% by mass of a diene rubber. More preferably, it comprises 10 to 90% by mass of a diene polymer and 90 to 10% by mass of a diene rubber. Here, as the diene rubber, other than the modified conjugated diene polymer according to the present invention, polybutadiene, polyisoprene, butadiene-isoprene copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene- Examples include isoprene-butadiene terpolymers, ethylene-propylene-diene terpolymers, butyl rubber, and halogenated butyl rubber. Of these diene rubbers, natural rubber is preferred. The reason why the modified conjugated diene polymer is 10% by mass or more in the rubber matrix is to achieve the effects of on-ice performance and low rolling resistance.

The rubber composition used in the pneumatic tire of the present invention contains 5 to 200 parts by mass, preferably 20 to 120 parts by mass, more preferably 30 to 100 parts by mass of the reinforcing filler with respect to 100 parts by mass of the rubber matrix. Is included. If the reinforcing filler is less than 5 parts by mass, the interaction between the high molecular weight modified conjugated diene polymer and the reinforcing filler cannot be enjoyed, and if the reinforcing filler exceeds 200 parts by mass, the winter This is because the rolling resistance of the industrial pneumatic tire is remarkably increased.
In the present invention, the reinforcing filler is preferably carbon black and / or silica.
The high molecular weight modified conjugated diene polymer represented by the general formula (2) or the general formula (3) preferably reacts with both carbon black and silica. When combined with natural rubber, silica is more likely to be present in the natural rubber and the high molecular weight modified conjugated diene polymer reacts with the silica so that more silica is contained in the high molecular weight modified conjugated diene polymer. Since the dynamic storage elastic modulus E ′ at −20 ° C. of the tread rubber composition is remarkably reduced, the tread flexibility at −20 ° C. is increased and the performance on ice is further improved.
Moreover, since the high molecular weight modified conjugated diene polymer having the functional group represented by the general formula (2) or the general formula (3) at the molecular chain end reacts suitably with both carbon black and silica, Since the dispersibility of both black and silica is improved and the dynamic storage elastic modulus E ′ at 30 ° C. of the tread rubber composition is increased, the dry handling stability performance of the winter pneumatic tire of the present invention is improved.
From the above viewpoint, the rubber matrix is more preferably a combination of the modified conjugated diene polymer and natural rubber (modified conjugated diene polymer 10 to 100% by mass and natural rubber 90 to 0% by mass), and has a reinforcing property. A combination of carbon black and silica (10 to 90% by mass of carbon black and 90 to 10% by mass of silica, more preferably 20 to 80% by mass of carbon black and 80 to 20% by mass of silica) is further preferable as a filler.

The carbon black used as the reinforcing filler preferably has a nitrogen adsorption specific surface area (N ₂ SA, measured according to JIS K 6217-2: 2001) of 70 to 200 m ² / g. Examples of the carbon black in this range include SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, N285, N339, HAF-HS, HAF, HAF-LS and the like. The carbon black nitrogen adsorption specific surface area is particularly preferably 85 to 180 m ² / g.

Any commercially available silica can be used as the reinforcing filler, and wet silica, dry silica and colloidal silica are particularly preferable, and wet silica is particularly preferable. The BET specific surface area (measured according to ISO 5794/1) of silica is preferably 100 m ² / g or more, more preferably 150 m ² / g or more, particularly preferably 170 m ² / g or more. Examples of such silica include Tosoh Silica Co., Ltd., trade name “Nipsil AQ” (BET specific surface area = 190 m ² / g), “Nipsil KQ”, Degussa Co., trade name “Ultrazil VN3” (BET specific surface area = 175 m). ² / g) can be used.

In addition to the reinforcing filler, the following inorganic filler may be blended if desired. For example, alumina (Al ₂ O ₃ ), alumina hydrate (Al ₂ O ₃ .H ₂ O), aluminum hydroxide [Al (OH) ₃ ], aluminum carbonate [Al ₂ (CO ₃ ) ₂ ], water magnesium oxide [Mg (OH) _2], magnesium oxide (MgO), magnesium carbonate (MgCO _3), talc _{(3MgO · 4SiO 2 · H 2} O), attapulgite _{(5MgO · 8SiO 2 · 9H 2} O), titanium white ( TiO ₂ ), titanium black (TiO _2n-1 ), calcium oxide (CaO), calcium hydroxide [Ca (OH) ₂ ], aluminum magnesium oxide (MgO · Al ₂ O ₃ ), clay (Al ₂ O ₃ · 2SiO) _2), kaolin _{(Al 2 O 3 · 2SiO 2} · 2H 2 O), pyrophyllite _{(Al 2 O 3 · 4SiO 2} · H 2 O), bentonite _{(Al 2 O 3 · 4SiO 2} · 2 ₂ O), aluminum silicate _{(Al 2 SiO 5, Al 4} · 3SiO 4 · 5H 2 O etc.), magnesium silicate (Mg ₂ SiO _4, MgSiO ₃ etc.), calcium silicate (Ca ₂ · SiO ₄ etc.) , Aluminum calcium silicate (Al ₂ O ₃ · CaO · 2SiO ₂ etc.), magnesium calcium silicate (CaMgSiO ₄ ), calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO ₂ ), zirconium hydroxide [ZrO (OH) ₂ · nH ₂ O], zirconium carbonate _{[Zr (CO 3) 2]} , and the like crystalline aluminosilicate.

When silica is added to the rubber composition used in the pneumatic tire of the present invention, it is preferable that 1 to 20% by mass of a silane coupling agent is added to silica. Examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (3-methyldimethoxysilylpropyl) tetrasulfide, and bis (3-triethoxy Silylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (3-methyldimethoxysilylpropyl) disulfide, bis (3-triethoxysilylethyl) disulfide, Bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-methyldimethoxysilylpropyl) trisulfide, bis (3-triethoxysilylethyl) Le) sulfur-containing alkoxysilane compounds such trisulfide and the like.

In the rubber composition used in the pneumatic tire of the present invention, 1 to 15 parts by mass of a foaming agent is preferably blended with 100 parts by mass of the rubber matrix.
Examples of the foaming agent include azodicarbonamide (ADCA), dinitrosopentamethylenetetramine (DPT), dinitrosopentastyrenetetramine, benzenesulfonylhydrazide derivatives, p, p'-oxybisbenzenesulfonylhydrazide (OBSH), carbon dioxide. Ammonium bicarbonate generated, sodium bicarbonate, ammonium carbonate, nitrososulfonylazo compound generating nitrogen, N, N′-dimethyl-N, N′-dinitrosophthalamide, toluenesulfonyl hydrazide, p-toluenesulfonyl semicarbazide, p , p′-oxybisbenzenesulfonyl semicarbazide and the like. Among these foaming agents, azodicarbonamide (ADCA) and dinitrosopentamethylenetetramine (DPT) are preferable from the viewpoint of production processability. Moreover, these foaming agents may be used individually by 1 type, and may use 2 or more types together.

The form of the foaming agent is not particularly limited, and can be appropriately selected from particulate, liquid, etc. according to the purpose. The form of the foaming agent can be observed using, for example, a microscope. Moreover, the average particle diameter of a particulate foaming agent can be measured using a Coulter counter etc., for example.

In addition, it is preferable to use urea, zinc stearate, zinc benzenesulfinate, zinc white or the like in combination with the foaming agent as a foaming aid. These may be used alone or in combination of two or more. By using a foaming aid in combination, the foaming reaction can be promoted to increase the degree of completion of the reaction, and unnecessary deterioration can be suppressed over time.

The tread of the winter pneumatic tire of the present invention preferably has 5 to 50% by volume of air bubbles in the rubber matrix. The bubble rate (Vs) can be calculated by the following equation.
Vs = (ρ ₀ / ρ ₁ −1) × 100 (%)
(Wherein, [rho ₁ represents the density of the rubber composition after vulcanization ^{(g / cm 3), ρ} 0 represents the density of the solid phase portion in the rubber composition after vulcanization (g / cm ^3). )
The density of the rubber composition after vulcanization and the density of the solid phase part in the rubber composition after vulcanization are calculated from the mass in ethanol and the mass in air. Further, the bubble ratio (Vs) can be appropriately changed depending on the types and amounts of the foaming agent and the foaming aid described above.
The reason why the bubble rate is preferably 5% by volume or more is that the performance on ice can be further improved, and that the bubble rate is preferably 50% by volume or less is due to wear resistance and fracture resistance. It is because it improves more.
From the viewpoints described above, the bubble ratio is more preferably 5 to 40% by volume, and particularly preferably 5 to 35% by volume.

The rubber composition used in the pneumatic tire of the present invention is a short fiber made of a thermoplastic resin, and the rubber is in the range until the temperature of the rubber composition reaches the maximum vulcanization temperature when vulcanized. You may contain the short fiber characterized by melting or softening in the matrix of a composition. Here, the blending amount of the short fibers is 0.2 to 10 parts by mass, preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the rubber matrix. The maximum vulcanization temperature means the maximum temperature reached by the rubber composition during vulcanization. For example, in the case of mold vulcanization, it means the maximum temperature that the rubber composition reaches from the time when the rubber composition enters the mold until the rubber composition exits the mold and cools. The maximum vulcanization temperature can be measured, for example, by embedding a thermocouple in the rubber composition.
When the rubber composition used in the winter pneumatic tire of the present invention contains the short fibers, after the vulcanization, there are long bubbles in the tread, and the long bubbles are exposed on the surface due to wear of the tread. Thus, a hole is formed and functions as a drainage channel for efficient drainage. Here, the hole portion may be any one of a hole shape, a hollow shape, and a groove shape. Moreover, since the surface of the hole part of the tread is covered with a solidified protective layer of melted or softened short fibers, it is excellent in water channel shape retention, water channel edge wear, water channel retention during load input, and the like. The thickness of the protective layer is preferably 0.5 to 50 μm.

The material of the short fiber is not particularly limited as long as it is a thermoplastic resin having the thermal characteristics, and can be appropriately selected according to the purpose. Preferred examples of the short fibers having the thermal characteristics include short fibers made of a crystalline polymer having a melting point lower than the maximum vulcanization temperature. The short fiber made of the crystalline polymer will be described as an example. The larger the difference between the melting point of the short fiber and the maximum vulcanization temperature of the rubber composition, the faster the vulcanization of the rubber composition. The short fibers melt. On the other hand, when the melting point of the short fiber is too close to the maximum vulcanization temperature of the rubber composition, the short fiber does not melt quickly at the initial stage of vulcanization, and the short fiber melts at the end of vulcanization. At the end of vulcanization, the air present in the short fibers diffuses and is dispersed or taken into the vulcanized rubber composition, and a sufficient amount of air is retained in the melted short fibers. Not. On the other hand, if the melting point of the short fiber is too low, the short fiber is melted by heat at the time of kneading the rubber composition, poor dispersion due to fusion of the short fibers at the kneading stage, and short fiber at the kneading stage. Is disadvantageous in that it is divided into a plurality of lengths, and short fibers are dissolved in the rubber composition and dispersed microscopically.

The upper limit of the melting point (or softening point) of the short fiber is not particularly limited, but is preferably selected in consideration of the above points. Generally, it is higher than the maximum vulcanization temperature of the rubber composition. It is preferably lower by 10 ° C. or higher, and more preferably lower by 20 ° C. or higher. The industrial vulcanization temperature of the rubber composition is generally about 190 ° C. at the maximum. For example, when the maximum vulcanization temperature is set to 190 ° C., the melting point of the short fiber is Is usually selected within a range of 190 ° C. or lower, preferably 180 ° C. or lower, and more preferably 170 ° C. or lower. On the other hand, considering the kneading of the rubber composition, the melting point (or softening point) of the short fibers is preferably 5 ° C. or more, more preferably 10 ° C. or more, and more preferably 20 ° C. with respect to the maximum temperature during kneading. The above is particularly preferable. Assuming that the maximum temperature in kneading the rubber composition is, for example, 95 ° C., the melting point of the short fibers is preferably 100 ° C. or higher, more preferably 105 ° C. or higher, and particularly preferably 115 ° C. or higher. The melting point of the short fibers can be measured using a known melting point measuring device or the like. For example, the melting peak temperature measured using a DSC measuring device can be used as the melting point.

The short fiber may be formed from the above-described crystalline polymer, may be formed from an amorphous polymer, or may be formed from a crystalline polymer and an amorphous polymer. However, in the present invention, it is preferably formed of an organic material containing a crystalline polymer from the viewpoint that viscosity change occurs suddenly at a temperature where there is a phase transition and viscosity control is easy. More preferably, it is formed only from a functional polymer.

Examples of the crystalline polymer include polyethylene (PE), polypropylene (PP), polybutylene, polybutylene succinate, polyethylene succinate, syndiotactic-1,2-polybutadiene (SPB), polyvinyl alcohol (PVA), Single-composition polymers such as polyvinyl chloride (PVC), those having a melting point controlled to an appropriate range by copolymerization, blending, or the like can be used, and those obtained by adding additives to these can also be used. These may be used alone or in combination of two or more. Among these crystalline polymers, polyolefins and polyolefin copolymers are preferable, polyethylene (PE) and polypropylene (PP) are more preferable in terms of general availability and easy access, polyethylene (PE) in terms of low melting point and easy handling. ) Is particularly preferred.

Examples of the non-crystalline polymer include polymethyl methacrylate (PMMA), acrylonitrile / butadiene / styrene copolymer (ABS), polystyrene (PS), polyacrylonitrile, copolymers thereof, and blends thereof. Etc. These may be used alone or in combination of two or more. Further, the crystalline polymer and the amorphous polymer may be used in combination.

The fineness of the short fiber is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of improving the performance on ice and snow, 1 to 1100 dTex is preferable, and 2 to 900 dTex is more preferable. The average diameter (D) of the short fibers is not particularly limited and may be appropriately selected depending on the intended purpose. In the vulcanized rubber obtained by vulcanizing a rubber composition containing the short fibers In addition, in order to efficiently form long bubbles that can function as a micro drainage groove described later, 0.03 to 0.3 mm is preferable, and 0.06 to 0.25 mm is more preferable. If the average diameter (D) is less than 0.03 mm, it is difficult to form a long cylindrical foaming groove, and it is not preferable in that many yarn breaks occur during the production of the short fibers, and 0.3 mm is preferable. When it exceeds, the average diameter (diameter) of the said short fiber will become large, and the number of cylindrical foaming grooves will decrease in the same compounding quantity, and there exists a tendency for drainage efficiency to worsen.

The rubber composition used in the pneumatic tire of the present invention is preferably 3 to 30 parts by mass, more preferably 3 to 30 parts by mass of fine particles having an average major axis of 5 to 1000 μm, preferably 5 to 500 μm with respect to 100 parts by mass of the rubber matrix. May contain 3 to 15 parts by mass.
This fine particle (1) scratches the surface of the ice on the tread surface to improve the grip on ice, and (2) the fine particle is detached from the tread, and a hole is formed in the surface layer portion of the tread (the tread surface and its vicinity). It forms and drains the melted water from the ice on the ice. The average major axis of the fine particles refers to the average maximum diameter.
Here, the average major axis of the fine particles is preferably 5 μm or more because the performance on ice is further improved due to the scratch effect, and the average major axis of the fine particles is preferably 1000 μm or less because of wear resistance. This is because the fracture resistance is further improved.
Further, it is preferable to contain 3 parts by mass or more of fine particles because the performance on ice is further improved, and it is preferable to contain 15 parts by mass or less of fine particles to improve wear resistance and fracture resistance. Because.
The average major axis is obtained by randomly selecting 100 fine particles with an electron microscope, measuring each major axis, and arithmetically averaging the measured 100 major axes.

The fine particles preferably have an aspect ratio of 1.1 or more, and preferably have corners. More preferably, the aspect ratio is 1.2 or more, and further preferably 1.3 or more. Here, the presence of a corner means that the entire surface is not a spherical surface or a smooth curved surface. Fine particles having corners can be used from the beginning for the fine particles of the present invention, but even if the fine particles are spherical, they can be used with the corners existing on the surface of the fine particles, and more Corners can be present.

The fine particles blended in the rubber composition used in the pneumatic tire of the present invention are not limited to those described above, and may be present after vulcanization as fine particles without being softened by vulcanization of the pneumatic tire. good. As the fine particles, fine particles having a Mohs hardness of 2 or more are preferable. For example, gypsum fine particles, calcite fine particles, fluorite fine particles, feldspar fine particles, quartz fine particles, olivine fine particles, iron fine particles, eggshell powder, zirconium oxide fine particles, calcium carbonate Plant fine particles, silica fine particles, wollastonite fine particles, alkali feldspar fine particles, natural silicon oxide fine particles, inorganic fine particles such as porous natural glass (for example, Mohs hardness 5) fine particles, walnut shells and other seed shells and fruit nuclei Fine particles, organic cured fine particles such as (meth) acrylic cured resin fine particles, epoxy cured resin fine particles, zinc oxide whiskers (for example, Panatetra (tetrapot-shaped zinc oxide) manufactured by Matsushita Amtech Co., Ltd.), stars from Okinawa Prefecture Sand, glass fiber, aluminum whisker, polyester fiber, nylon fiber, polyvinyl Examples include short fibers that do not soften or melt at the vulcanization temperature of pneumatic tires such as lumar fibers and aromatic polyamide fibers, expanded graphite, thermally expanded microcapsules, and shirasu balloons, more preferably silica having a Mohs hardness of 5 or more. Glass (Mohs hardness 6.5), quartz (Mohs hardness 7.0), fused alumina (Mohs hardness 9.0), etc. can be mentioned. Among these, alumina (aluminum oxide) such as single crystal alumina and polycrystalline alumina, silica glass, and the like are particularly preferable because they are inexpensive and can be used easily.

The above-mentioned expanded graphite is a powder substance having an average major axis of 30 to 600 μm, preferably 100 to 350 μm, as a particle size including a substance that is vaporized by heat between layers of graphite particles, and expands by heat during vulcanization. It is preferable that it becomes a graphite expanded body (Expanded Graphite).
Expanded graphite has a structure in which sheets formed from carbon atoms overlap each other and includes a vaporizable interlayer material between the layers. For example, the interlayer material is vaporized and expanded by heating to form a graphite expanded body. Since the material is hard before expansion treatment, quality deterioration due to mixing is unlikely to occur, and because it expands irreversibly at a constant temperature, foreign matter with space can be easily formed inside the rubber matrix by vulcanization of a pneumatic tire. Can do. The tread portion of a pneumatic tire using such a rubber has surface irregularities that are moderately formed during wear, like other fine particles, and the water film on the contact surface between the ice and the pneumatic tire can be efficiently removed. Move to improve friction.

As the expanded graphite having an expansion start temperature of 190 ° C. or less, for example, “Graph Guard 160-50” or “Graph Guard 160-80” manufactured by UCAR® Graphtech in the United States is commercially available from Sakai Industries. . Expanded graphite refers to an unexpanded product immediately after acid treatment in terms of term, but may also refer to an already expanded product after heat treatment. The expanded graphite blended as a rubber composition in the present invention is an unexpanded product before heat treatment.

The thermal expansion microcapsules described above are powder particles in which a liquid or solid that is vaporized, decomposed, or chemically reacted by heat to generate a gas is encapsulated in a thermoplastic resin, and have a temperature equal to or higher than the expansion start temperature, usually 140. When heated at a temperature of ˜190 ° C., it expands and a gas is contained in the outer shell made of the thermoplastic resin. The average major axis of the thermoplastic resin particles is preferably 5 to 300 μm before expansion, More preferably, the average major axis is 10 to 200 μm.

As such heat-expandable thermoplastic resin particles, for example, the product name “Expancel 091DU-80” or “Expancel 092DU-120” is currently available from EXPANCEL, Sweden, or from Matsumoto Yushi. The names “Matsumoto Microsphere F-85” or “Matsumoto Microsphere F-100” are available.

As described above, it is preferable that the fine particles are detached from the tread to form a hole in the tread surface layer portion (tread surface and its vicinity). For this purpose, the fine particles are bonded to the tread rubber composition by vulcanization. It is desirable that the vulcanized adhesive strength is low.

When the fine particles are blended in the rubber composition used in the pneumatic tire of the present invention, it may be blended as a non-linear fine particle-containing resin body containing fine particles. Here, the fine particle-containing resin body is preferably blended in an amount of 3 to 30 parts by mass with respect to 100 parts by mass of the rubber matrix, and the average particle size of the fine particle-containing resin body is preferably 10 to 1000 μm. This resin body melts or softens in the matrix of the rubber composition until the temperature of the rubber composition reaches the maximum vulcanization temperature at the time of vulcanization of the pneumatic tire. It consists of the same material as the short fiber which melts or softens during vulcanization. In addition, the measuring method of the average particle diameter of the fine particle-containing resin body is the same as the measuring method of the average long diameter of the fine particles.

Further, fine particles are contained in the above-mentioned short fibers that melt or soften in the matrix of the rubber composition until the temperature of the rubber composition reaches the maximum vulcanization temperature during vulcanization of the pneumatic tire. You may mix | blend as a containing short fiber. The constitution and material of the short fibers that melt or soften during vulcanization of the pneumatic tire are as described above. The blending amount of the fine particle-containing short fibers is preferably 3 to 20 parts by mass, and more preferably 3 to 15 parts by mass with respect to 100 parts by mass of the rubber matrix of the rubber composition of the present invention.

If desired, the rubber composition used in the pneumatic tire of the present invention may further contain 1 to 50 parts by mass of a softening agent with respect to 100 parts by mass of the rubber matrix. It is because processability is improved by blending the softener.
In addition, when blending both the low molecular weight modified conjugated diene polymer and the softener, the total blended amount of the low molecular weight modified conjugated diene polymer and the softener is 100 parts by weight of the rubber matrix. 6 to 60 parts by mass is preferable. This is because workability is improved when the amount is 6 parts by mass or more, and wear resistance and fracture resistance are improved when the amount is 60 parts by mass or less. From these viewpoints, the total blending amount of the low molecular weight modified conjugated diene polymer and the softening agent is preferably 6 to 55 parts by mass, and more preferably 6 to 50 parts by mass.

In the rubber composition used in the pneumatic tire of the present invention, the softener that is optionally blended has a low pour point (for example, about pour point −10 to −60 ° C., preferably pour point −20 to −60). ° C, more preferably pour point -30 to -60 ° C) Process oil such as naphthenic process oil and paraffinic process oil, or dibutyl phthalate, di- (2-ethylhexyl) phthalate, butyl benzyl phthalate, di- Examples thereof include plasticizers such as n-octyl phthalate.

The rubber composition used in the pneumatic tire of the present invention is preferably sulfur crosslinkable, and sulfur is suitably used as a vulcanizing agent. The amount used is preferably 0.1 to 10 parts by mass of sulfur (the total amount of sulfur and sulfur donors) per 100 parts by mass of the rubber matrix. This is because within this range, the necessary elastic modulus and strength of the vulcanized rubber composition can be ensured and fuel efficiency can be obtained. From this viewpoint, it is more preferable to add 0.5 to 7 parts by mass of the sulfur content.

In the rubber composition used for the pneumatic tire of the present invention, various chemicals usually used in the rubber industry, for example, vulcanizing agents other than sulfur, vulcanization acceleration, as long as the object of the present invention is not impaired. Agent, process oil, anti-aging agent, scorch inhibitor, zinc white, stearic acid, thermosetting resin, thermoplastic resin, and the like.

The vulcanization accelerator that can be used in the present invention is not particularly limited, and examples thereof include M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), and CZ (N-cyclohexyl-2-benzothiazyl). Sulfenamide) and other guanidine vulcanization accelerators such as DPG (diphenylguanidine) can be used, and the amount used is 0.1-5. 0 parts by mass is preferable, and 0.2 to 3.0 parts by mass is more preferable.

Furthermore, examples of the anti-aging agent that can be used in the rubber composition used in the pneumatic tire of the present invention include 3C (N-isopropyl-N′-phenyl-p-phenylenediamine, 6C [N- (1,3-dimethyl). Butyl) -N′-phenyl-p-phenylenediamine], AW (6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline), high-temperature condensate of diphenylamine and acetone, and the like. The amount to be used is preferably 0.1 to 6.0 parts by mass, more preferably 0.3 to 5.0 parts by mass with respect to 100 parts by mass of the rubber matrix.

The rubber composition used for the pneumatic tire of the present invention is obtained by kneading using a kneader such as a Banbury mixer, a roll, an internal mixer or the like according to the above-mentioned blending prescription, and after extrusion molding, a tire molding machine After forming by the usual method above and forming a raw tire, vulcanization is performed to form a tread of a winter pneumatic tire (preferably a cap tread in a cap / base two-layer tread). .

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
The weight average molecular weight (Mw), the modified styrene content, the vinyl bond content, and the winter pneumatic tire before modification of the high molecular weight modified conjugated diene polymer and the low molecular weight modified conjugated diene polymer according to the present invention. The on-ice performance, wet steering stability performance and dry steering stability performance were measured according to the following methods.

<Weight average molecular weight (Mw) before modification>
It was measured by GPC [manufactured by Tosoh Corporation, HLC-8220] using a refractometer as a detector, and was shown in terms of polystyrene using monodisperse polystyrene as a standard. The column is GMHXL [manufactured by Tosoh] and the eluent is tetrahydrofuran.
<Bound styrene content>
It was determined by calculating the integral ratio of the spectrum by ¹ H-NMR.
<Vinyl bond content>
It calculated | required by the infrared method (Morero method).
<Performance on ice>
A slab sheet having a length of 40 mm, a width of 5 mm, and a thickness of 2 mm in the longitudinal direction of the tire was cut out from a tread of a winter pneumatic tire in a plane parallel to the ground contact surface having a depth of 1 mm from the groove bottom, and used as a sample. This sample was stored using a spectrometer manufactured by Ueshima Seisakusho Co., Ltd. under the conditions of a distance between chucks of 10 mm, an initial strain of 200 micrometers (microns), a dynamic strain of 1%, a frequency of 52 Hz, and a measurement temperature of −20 ° C. (E ′) was measured. The performance on ice of the winter pneumatic tire of Comparative Example 1 or 5 was taken as 100, and the index was expressed by the following formula. The larger the index value, the better the performance on ice.
Performance on ice (index) = {E ′ of tire of Comparative Example 1 or 5 (−20 ° C.) / E ′ of test tire (−20 ° C.)} × 100
<Wet handling stability>
The loss tangent (tan δ) was measured with the same spectrometer and measurement conditions as the performance on ice except that a sample similar to the performance on ice was used and the measurement temperature was 0 ° C. The wet steering stability performance of the winter pneumatic tire of Comparative Example 1 or 5 was taken as 100, and the index was expressed by the following formula. The larger the index value, the better the wet steering stability performance.
Wet steering stability performance (index) = {tan δ (0 ° C.) of test tire / tan δ (0 ° C.) of tire of Comparative Example 1 or 5} × 100
<Dry maneuvering stability>
The storage elastic modulus (E ′) was measured by using the same sample as the on-ice performance and using the same spectrometer and measurement conditions as the on-ice performance except that the measurement temperature was 30 ° C. The wet steering stability performance of the winter pneumatic tire of Comparative Example 1 or 5 was taken as 100, and the index was expressed by the following formula. The larger the index value, the better the wet steering stability performance.
Dry steering stability performance (index) = {E ′ of test tire (30 ° C.) / E ′ of tire of Comparative Example 1 or 5 (30 ° C.)} × 100

Production Example 1: Production of high molecular weight unmodified conjugated diene-based polymer A In a pressure-resistant glass container having an internal volume of about 900 ml which was dried and purged with nitrogen, 283 g of cyclohexane, 100 g of 1,3-butadiene monomer, 2,2-ditetrahydro 0.015 mmol of furylpropane was injected as a cyclohexane solution, 0.50 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. Thereafter, 0.5 ml of a 5% solution of 2,6-di-t-butyl-p-cresol (BHT) in 5% isopropanol was added to stop the reaction, followed by drying in accordance with a conventional method, whereby high molecular weight unmodified conjugated diene was obtained. A polymer A was obtained. The obtained high molecular weight unmodified conjugated diene polymer A had a vinyl bond content of 20% and a weight average molecular weight (Mw) of 300,000.

Production Example 2: Production of high molecular weight modified conjugated diene polymer B In a pressure-resistant glass container having an inner volume of about 900 ml which was dried and purged with nitrogen, 283 g of cyclohexane, 100 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl 0.015 mmol of propane was injected as a cyclohexane solution, 0.50 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. To this polymerization system, 0.125 mmol of tin tetrachloride was added as a cyclohexane solution and stirred at 50 ° C. for 30 minutes. Thereafter, 0.5 ml of a 5% isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT) was added to stop the reaction, followed by drying according to a conventional method to thereby modify the high molecular weight modified conjugated diene system. Polymer B was obtained. Tables 2 and 4 show the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained high molecular weight modified conjugated diene polymer B.

Production Example 3 Production of High Molecular Weight Modified Conjugated Diene Polymer C In a pressure-resistant glass container having an internal volume of about 900 ml which was dried and purged with nitrogen, 283 g of cyclohexane, 100 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl 0.015 mmol of propane was injected as a cyclohexane solution, 0.50 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The reaction conversion of 1,3-butadiene was almost 100%. Further, 0.55 mmol of N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine was added as a non-end modifier, and the modification reaction was further performed for 30 minutes. Thereafter, a methanol solution containing 1.5 g of 2,4-tert-butyl-p-cresol was added to terminate the polymerization, and further dried according to a conventional method to obtain a high molecular weight modified conjugated diene polymer C. Got. Table 4 shows the vinyl bond content% and the weight average molecular weight (Mw) before modification of the obtained high molecular weight modified conjugated diene polymer C.

Production Example 4: Production of High Molecular Weight Modified Conjugated Diene Polymer D High molecular weight modified conjugated diene heavy polymer in the same manner as in Production Example 2 except that the tin tetrachloride of Production Example 2 was changed to equimolar tetraethoxysilane. Combined D was obtained. Table 2 shows the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained high molecular weight modified conjugated diene polymer D.

Production Example 5 Production of High Molecular Weight Modified Conjugated Diene Polymer E In a pressure-resistant glass container having an internal volume of about 900 milliliters that has been dried and purged with nitrogen, 283 g of cyclohexane, 100 g of 1,3-butadiene monomer, 2,2-ditetrahydro 0.015 mmol of furylpropane was injected as a cyclohexane solution, 0.50 mmol of lithium hexamethyleneimide was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion rate was almost 100%. Thereafter, 0.5 ml of 2,6-di-tert-butyl-p-cresol (BHT) isopropanol 5% by mass solution was added to stop the reaction, followed by drying according to a conventional method to modify the high molecular weight. A conjugated diene polymer E was obtained. Table 4 shows the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained high molecular weight modified conjugated diene polymer E.

Production Example 6: Production of high molecular weight modified conjugated diene polymer F Production Example 2 except that tin tetrachloride of Production Example 2 was changed to equimolar N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane. Similarly, a high molecular weight modified conjugated diene polymer F was obtained. Table 2 shows the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained high molecular weight modified conjugated diene polymer F.

Production Example 7 Production of High Molecular Weight Modified Conjugated Diene Polymer G In a pressure-resistant glass container having an internal volume of about 2000 ml that has been dried and purged with nitrogen, 700 g of cyclohexane, 250 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl 0.015 mmol of propane was injected as a cyclohexane solution, 0.50 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. To this polymerization system, 0.125 mmol of tin tetrachloride was added as a cyclohexane solution and stirred at 50 ° C. for 30 minutes. Thereafter, 0.5 ml of a 5% solution of 2,6-di-t-butyl-p-cresol (BHT) in isopropanol was added to stop the reaction, followed by drying in accordance with a conventional method, whereby a high molecular weight modified conjugated diene was obtained. A polymer G was obtained. Table 4 shows the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained high molecular weight modified conjugated diene polymer G.

Production Example 8 Production of Low Molecular Weight Unmodified Conjugated Diene Polymer H In a pressure-resistant glass container having an internal volume of about 900 ml that was dried and purged with nitrogen, 283 g of cyclohexane, 25 g of 1,3-butadiene monomer, and 2,2-ditetrahydro 0.015 mmol of furylpropane was injected as a cyclohexane solution, 0.50 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. Thereafter, the reaction was stopped by adding 0.5 ml of a 5% isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT), followed by drying according to a conventional method. Diene polymer H was obtained. Tables 2 and 4 show the vinyl bond content and the weight average molecular weight (Mw) before modification of the low molecular weight unmodified conjugated diene polymer H obtained.

Production Example 9 Production of Low Molecular Weight Modified Conjugated Diene Polymer I In a pressure-resistant glass container having an internal volume of about 900 ml that was dried and purged with nitrogen, 283 g of cyclohexane, 25 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl 0.015 mmol of propane was injected as a cyclohexane solution, 0.50 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. To this polymerization system, 0.125 mmol of tin tetrachloride was added as a cyclohexane solution and stirred at 50 ° C. for 30 minutes. Thereafter, 0.5 ml of a 5% isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT) was added to stop the reaction, followed by drying according to a conventional method, thereby reducing the low molecular weight modified conjugated diene system. Polymer I was obtained. Tables 2 and 4 show the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained low molecular weight modified conjugated diene polymer I.

Production Example 10 Production of Low Molecular Weight Modified Conjugated Diene Polymer J In a pressure-resistant glass container having an internal volume of about 900 ml which was dried and purged with nitrogen, 283 g of cyclohexane, 25 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl 0.63 mmol of propane was injected as a cyclohexane solution, 21 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. hot water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. To this polymerization system, 5.25 mmol of tin tetrachloride was added as a cyclohexane solution and stirred at 50 ° C. for 30 minutes. Thereafter, 0.5 ml of a 5% isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT) was added to stop the reaction, followed by drying according to a conventional method, thereby reducing the low molecular weight modified conjugated diene system. Polymer J was obtained. Table 4 shows the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained low molecular weight modified conjugated diene polymer J.

Production Example 11 Production of Low Molecular Weight Modified Conjugated Diene Polymer K In a pressure-resistant glass container having an internal volume of about 900 ml, dried and purged with nitrogen, 283 g of cyclohexane, 25 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl 0.0055 mmol of propane was injected as a cyclohexane solution, 0.22 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. To this polymerization system, 0.055 mmol of tin tetrachloride was added as a cyclohexane solution and stirred at 50 ° C. for 30 minutes. Thereafter, 0.5 ml of a 5% isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT) was added to stop the reaction, followed by drying according to a conventional method, thereby reducing the low molecular weight modified conjugated diene system. A polymer K was obtained. Table 4 shows the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained low molecular weight modified conjugated diene polymer K.

Production Example 12 Production of Low Molecular Weight Modified Conjugated Diene Polymer L In a pressure-resistant glass container having an internal volume of about 900 ml that was dried and purged with nitrogen, 283 g of cyclohexane, 25 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl 0.015 mmol of propane was injected as a cyclohexane solution, 0.50 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. To this polymerization system, 0.125 mmol of tetraethoxysilane was added as a cyclohexane solution and stirred at 50 ° C. for 30 minutes. Thereafter, 0.5 ml of a 5% isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT) was added to stop the reaction, followed by drying according to a conventional method, thereby reducing the low molecular weight modified conjugated diene system. Polymer L was obtained. The vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained low molecular weight modified conjugated diene polymer L are shown in Tables 2 and 4.

Production Example 13 Production of Low Molecular Weight Modified Conjugated Diene Polymer M In a pressure-resistant glass container having an internal volume of about 900 ml that was dried and purged with nitrogen, 283 g of cyclohexane, 25 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl 0.015 mmol of propane was injected as a cyclohexane solution, 0.50 mmol of lithium hexamethyleneimide was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. Thereafter, 0.5 ml of a 5% isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT) was added to stop the reaction, followed by drying according to a conventional method, thereby reducing the low molecular weight modified conjugated diene system. A polymer M was obtained. Table 4 shows the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained low molecular weight modified conjugated diene polymer M.

Production Example 14 Production of Low Molecular Weight Modified Conjugated Diene Polymer N In a pressure-resistant glass container having an internal volume of about 900 ml that was dried and purged with nitrogen, 283 g of cyclohexane, 25 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl 0.015 mmol of propane was injected as a cyclohexane solution, 0.50 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. To this polymerization system, 0.50 mmol of N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane was added as a cyclohexane solution and stirred at 50 ° C. for 30 minutes. Thereafter, 0.5 ml of a 5% isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT) was added to stop the reaction, followed by drying according to a conventional method, thereby reducing the low molecular weight modified conjugated diene system. Polymer N was obtained. Table 4 shows the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained low molecular weight modified conjugated diene polymer N.

Production Example 15 Production of Low Molecular Weight Modified Conjugated Diene Polymer O In a pressure-resistant glass container having an internal volume of about 900 ml, dried and purged with nitrogen, 283 g of cyclohexane, 25 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl 0.048 mmol of propane was injected as a cyclohexane solution, 1.6 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. To this polymerization system, 0.40 mmol of tin tetrachloride was added as a cyclohexane solution and stirred at 50 ° C. for 30 minutes. Thereafter, 0.5 ml of a 5% isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT) was added to stop the reaction, followed by drying according to a conventional method, thereby reducing the low molecular weight modified conjugated diene system. Polymer O was obtained. Table 4 shows the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained low molecular weight modified conjugated diene polymer O.

Production Example 16 Production of Low Molecular Weight Modified Conjugated Diene Polymer P In a pressure-resistant glass container having an internal volume of about 900 ml which was dried and purged with nitrogen, 283 g of cyclohexane, 25 g of 1,3-butadiene monomer, 2,2-ditetrahydrofuryl After injecting 0.0080 mmol of propane as a cyclohexane solution, 0.27 mmol of n-butyllithium (BuLi) was added thereto, and then polymerization was performed in a 50 ° C. warm water bath equipped with a stirrer for 4.5 hours. The polymerization conversion was almost 100%. To this polymerization system, 0.067 mmol of tin tetrachloride was added as a cyclohexane solution and stirred at 50 ° C. for 30 minutes. Thereafter, 0.5 ml of a 5% isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT) was added to stop the reaction, followed by drying according to a conventional method, thereby reducing the low molecular weight modified conjugated diene system. A polymer P was obtained. Table 4 shows the vinyl bond content and the weight average molecular weight (Mw) before modification of the obtained low molecular weight modified conjugated diene polymer P.

Production Example 17: Synthesis of N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane 36 g of 3-aminopropylmethyldiethoxysilane as an aminosilane moiety in 400 ml of dichloromethane solvent in a glass flask equipped with a stirrer under a nitrogen atmosphere After addition of (Gelest), 48 ml of trimethylsilane chloride (Aldrich) and 53 ml of triethylamine were added to the solution as protective sites, and the mixture was stirred at room temperature for 17 hours, and then the solvent was removed by applying the reaction solution to an evaporator. Was removed by distillation under reduced pressure under 5 mm / Hg conditions to obtain 40 g of N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane as a 130-135 ° C. fraction. Obtained. The N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane was produced in Production Example 6 (Production of high molecular weight modified conjugated diene polymer F) and Production Example 14 (Production of low molecular weight modified conjugated diene polymer N). Using.

Examples 1 to 3 and Comparative Examples 1 to 4
Among the high molecular weight or low molecular weight unmodified or modified conjugated diene polymers A to P obtained in Production Examples 1 to 16, using the conjugated diene polymers shown in Table 2, and according to the formulation shown in Table 1, Seven types of rubber compositions of Examples 1 to 3 and Comparative Examples 1 to 4 were prepared. In the rubber composition of Comparative Example 3, the cell ratio was lowered by increasing the vulcanization pressure.
Next, these seven kinds of rubber compositions are respectively arranged on the tread of a studless tire (tire size 195 / 60R15) which is a winter pneumatic tire, and seven kinds of studless tires are manufactured according to a conventional method. Each type of winter pneumatic tire was evaluated on ice performance, wet handling stability and dry handling stability according to the above-mentioned methods. The results are shown in Table 2.

[note]
1) High molecular weight (un) modified conjugated diene polymer: various polymers obtained in Production Examples 1, 2, 4 and 6 2) Carbon black: ISAF {N ₂ SA (m ² / g) = 115 (m ² / g)}, manufactured by Asahi Carbon Co., Ltd., trade name “Asahi # 80”
3) Silica: Tosoh Silica, trade name “Nipsil AQ” (BET specific surface area = 190 m ² / g)
4) Silane coupling agent: bis (3-triethoxysilylpropyl) tetrasulfide, manufactured by Degussa, trade name “Si69”
5) Low molecular weight (un) modified conjugated diene polymer: polymer obtained in Production Examples 8 and 9) Anti-aging agent IPPD: N-phenyl-N′-isopropylphenyl-p-phenylenediamine, Seiko Chemical ( "Ozonon 3C", manufactured by
7) Vulcanization accelerator MBTS: Dibenzothiazyl disulfide, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller DM”
8) Vulcanization accelerator CBS: N-cyclohexyl-2-benzothiazylsulfenamide, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller CZ”
9) Foaming agent: {Dinitrosopentamethylenetetramine (DPT)} / Urea} = 1/1 mixed product 10) Fine particles: Alumina powder, average major axis 60 μm, trade name “Standard Alumina A- 12 "

[note]
11) Modifier A: Tetraethoxysilane 12) Modifier B: N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane

As is apparent from Table 2, the rubber compositions of Examples 1 to 3 and the winter pneumatic tire using the rubber compositions of Examples 1 to 3 according to the present invention are used for the rubber compositions of Comparative Examples 1 to 4 and the tread of the rubber compositions. Compared to winter pneumatic tires, the wet steering stability and dry steering stability were maintained at the same level or higher, and the performance on ice was dramatically improved.

Examples 4 to 17 and Comparative Examples 5 to 9
Among the high molecular weight or low molecular weight unmodified or modified conjugated diene polymers A to K obtained in Production Examples 1 to 11, using the conjugated diene polymers shown in Table 4, according to the formulation shown in Table 3, Nineteen types of rubber compositions of Examples 4 to 17 and Comparative Examples 5 to 9 were prepared.
Next, these 19 kinds of rubber compositions are respectively arranged on the treads of studless tires (tire size 195 / 60R15) which are winter pneumatic tires, and 19 kinds of studless tires are produced according to a conventional method. Each type of tire was evaluated for its on-ice performance, wet handling stability and dry handling stability according to the above method. The results are shown in Table 4.

[note]
1) High molecular weight (un) modified conjugated diene polymer: Various polymers obtained in Production Examples 1 to 3, 5, 6 and 7 2) Carbon black: ISAF {N ₂ SA (m ² / g) = 115 (M ² / g)}, manufactured by Asahi Carbon Co., Ltd., trade name “Asahi # 80”
3) Silica: Tosoh Silica, trade name “Nipsil AQ” (BET specific surface area = 190 m ² / g)
4) Silane coupling agent: bis (3-triethoxysilylpropyl) tetrasulfide, manufactured by Degussa, trade name “Si69”
5) Low molecular weight (un) modified conjugated diene polymer: polymer obtained in Production Examples 9 to 16 6) Anti-aging agent IPPD: N-phenyl-N′-isopropylphenyl-p-phenylenediamine, Seiko Chemical ( Product name "Ozonon 3C"
7) Vulcanization accelerator MBTS: Dibenzothiazyl disulfide, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller DM”
8) Vulcanization accelerator CBS: N-cyclohexyl-2-benzothiazylsulfenamide, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller CZ”
9) Vulcanization accelerator DPG: Diphenyl guanidine, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller D”
10) Foaming agent: {dinitrosopentamethylenetetramine (DPT)} / urea} = 1/1 mixed product 11) Fine particles: alumina powder, average major axis 60 μm, manufactured by Showa Denko KK, trade name “Standard Alumina A- 12 "

[note]
12) Modifier H: Hexamethyleneimine (lithium hexamethyleneimide was used as an initiator)
13) Modifier C: N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine, manufactured by Chisso Corporation, trade name “Syra Ace S340”

[note]
14) Modifier A: Tetraethoxysilane 15) Modifier B: N, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane

As is apparent from Table 4, the rubber compositions of Examples 4 to 17 and the winter pneumatic tire using the rubber compositions of Examples 4 to 17 according to the present invention were used for the rubber compositions of Comparative Examples 5 to 9 and the treads. Compared to winter pneumatic tires, the wet steering stability and dry steering stability were maintained at the same level or higher, and the performance on ice was dramatically improved.

The rubber composition of the present invention is suitably used as a winter pneumatic tire for passenger cars, light cars, light trucks, trucks and buses, particularly a studless tire.

Claims (12)

1. The weight average molecular weight before modification is 2.0 × with respect to 100 parts by mass of the rubber matrix containing the high molecular weight modified conjugated diene polymer having a weight average molecular weight of more than 15 × 10 ⁴ and not more than 200 × 10 ⁴ before modification. A rubber composition comprising 5 to 50 parts by mass of a low molecular weight modified conjugated diene polymer of 10 ³ to 15 × 10 ⁴ and 20 to 200 parts by mass of a reinforcing filler, and a rubber matrix after vulcanization A pneumatic tire comprising a rubber composition having 5 to 50% by volume of air bubbles in the inside thereof.
2. The bonded aromatic vinyl content (X) (%) of the low molecular weight modified conjugated diene polymer and the vinyl bond content (Y) (%) of the conjugated diene moiety satisfy X + (Y / 2) <25. Item 2. The pneumatic tire according to Item 1.
3. The pneumatic according to claim 1 or 2, wherein the low molecular weight modified conjugated diene polymer contains at least one functional group selected from the group consisting of a tin-containing functional group, a silicon-containing functional group, and a nitrogen-containing functional group. tire.
4. The pneumatic tire according to any one of claims 1 to 3, wherein the low molecular weight modified conjugated diene polymer is low molecular weight modified polybutadiene and / or low molecular weight modified polyisoprene.
5. The high molecular weight modified conjugated diene polymer contains at least one functional group selected from the group consisting of a tin-containing functional group, a silicon-containing functional group, and a nitrogen-containing functional group. Pneumatic tires.
6. 6. The pneumatic tire according to claim 1, wherein the high molecular weight modified conjugated diene polymer is a modified polybutadiene rubber and / or a modified polyisoprene rubber.
7. The pneumatic tire according to any one of claims 1 to 6, wherein the reinforcing filler is carbon black and / or silica.
8. The pneumatic tire according to any one of claims 1 to 7, wherein the rubber matrix comprises 10 to 100% by mass of a high molecular weight modified conjugated diene polymer and 90 to 0% by mass of a diene rubber.
9. 9. The pneumatic tire according to claim 1, wherein the low molecular weight modified conjugated diene polymer has a weight average molecular weight before modification of 5.0 × 10 ³ to 10 × 10 ⁴ .
10. The pneumatic tire according to any one of claims 1 to 9, wherein the high molecular weight modified conjugated diene polymer has a weight average molecular weight of 20 × 10 ⁴ to 200 × 10 ⁴ before modification.
11. The pneumatic tire according to any one of claims 1 to 10, further comprising 3 to 30 parts by mass of fine particles having an average major axis of 5 to 1000 µm with respect to 100 parts by mass of the rubber matrix.
12. A winter pneumatic tire using the rubber composition as a tread, wherein the tread has 5 to 50% by volume of air bubbles in a rubber matrix, and the fine particles are removed from a surface layer portion of the tread. The pneumatic tire according to any one of claims 1 to 11, wherein the pneumatic tire has holes formed separately.