JP5466447B2 - Rubber composition and studless tire - Google Patents

Description

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

As pneumatic tires used for running on icy and snowy roads, studless tires are often used instead of conventional spike tires, and further improvement in performance on ice has been required. In order to improve the performance on ice and snow, the glass transition point (Tg) is lowered, and the elastic modulus at a low temperature (here, the low temperature is a temperature during running on ice and snow, which is about −20 to 0 ° C.). Many are set low.

However, since the elastic modulus at high temperature tends to decrease generally when the elastic modulus at low temperature is lowered, the conventional studless tire has a problem that the driving stability is inferior when traveling on a dry road surface. . The studless tire is also required to have other performances such as wear resistance and fatigue characteristics.

In response to the problem of lowering the elastic modulus at high temperature, in silica compounding, by adding a specific polar group to the rubber, it has an affinity for silica, and by increasing the dispersibility of silica, Attempts have been made to reduce the decline. For example, Patent Document 1 attempts to increase the affinity with silica by modifying rubber with an organosilicon compound containing an amino group and an alkoxy group, but a sufficient effect cannot be obtained.

JP 2000-344955 A

An object of the present invention is to solve the above-mentioned problems, and to provide a rubber composition capable of obtaining a good balance of wear resistance, performance on ice, and steering stability on a dry road surface, and a studless tire using the rubber composition.

The inventors of the present invention have intensively studied to obtain excellent wear resistance due to high cis content, excellent on-ice performance due to main chain and terminal modification, and steering stability on a dry road surface. It has been found that by using a polymer obtained by copolymerizing a polar group-containing vinyl compound, the wear resistance and the dispersibility of silica are improved from the conventional ones, and the above performance can be obtained in a well-balanced manner. Furthermore, it has been found that by using this polymer in combination with the epoxidized diene rubber, the dispersibility of silica is further improved, and the balance of these performances is remarkably improved, and the present invention has been completed.

The present invention is a rubber composition comprising a polar group-containing copolymer obtained by copolymerizing a conjugated diene compound and a polar group-containing vinyl compound, and an epoxidized conjugated diene polymer, the polar group-containing vinyl compound Has a polymerizable unsaturated bond and a polar group, and any carbon atom forming the polymerizable unsaturated bond and the carbon atom to which the polar group is bonded are bonded via at least one carbon atom. The rubber composition is a compound that binds, and the cis content of the double bond portion of the conjugated diene compound is 80 mol% or more.

The polar group is preferably a group represented by a hydroxyl group, —NR ₂ , or —Si (OR) _k (R) _3-k .
(However, R represents a C1-C8 hydrocarbon group, which may be the same or different.)

（式（Ｉ）中、Ｒ^１は、水素、ビニル基又は炭素数１〜３の脂肪族炭化水素基を表し、同一であっても異なっていてもよい。Ｒ^２は、水素又は炭素数１〜３の脂肪族炭化水素基を表し、同一であっても異なっていてもよい。Ｒ^３は、水素、又は炭素数１〜８の脂肪族若しくは脂環族炭化水素基を表す。Ｘは、水酸基、上記−ＮＲ_２、又は上記−Ｓｉ（ＯＲ）_ｋ（Ｒ）_３−ｋで表される基を表す。ｎは、１〜１０の整数を表す。上記Ｒ^１、Ｒ^２、Ｒ^３、該Ｒ^２が結合する炭素原子、該Ｒ^３が結合する炭素原子は、それぞれ互いに結合して環構造を形成してもよい。）
で表される化合物であることが好ましい。 The polar group-containing vinyl compound has the following general formula (I):

(In Formula (I), R ¹ represents hydrogen, a vinyl group, or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and may be the same or different. R ² represents hydrogen or one carbon atom. Represents an aliphatic hydrocarbon group having ˜3, which may be the same or different, R ³ represents hydrogen or an aliphatic or alicyclic hydrocarbon group having 1 to 8 carbon atoms, X is Represents a hydroxyl group, a group represented by —NR ₂ or the above —Si (OR) _k (R) _{3 —k} , n represents an integer of 1 to 10. The above R ¹ , R ² , R ³ , The carbon atom to which R ² is bonded and the carbon atom to which R ³ is bonded may be bonded to each other to form a ring structure.)
It is preferable that it is a compound represented by these.

0.1-20 mass% of structural units A in which the polar group-containing copolymer has 50 mass% or less of units derived from the conjugated diene compound and 50 mass% or more of units derived from the polar group-containing vinyl compound. Including 80 to 99.9% by mass of structural unit B having 60% by mass or more of units derived from the conjugated diene compound and 40% by mass or less of units derived from the polar group-containing vinyl compound, and having the polarity It is preferable to have this structural unit A in the terminal part of a group containing copolymer.

The polar group-containing copolymer is further converted into a copolymer having an active terminal obtained by copolymerizing the conjugated diene compound and the polar group-containing vinyl compound using a transition metal-containing compound as a catalyst. It is preferable that it is obtained by reacting a group-containing vinyl compound with the active terminal.

The polar group-containing copolymer has a weight average molecular weight of 1.0 × 10 ^{3 to} 2.0 × 10 ⁶ and a content of the polar group-containing vinyl compound of 0.03 to 40% by mass. Is preferred.
The conjugated diene compound is preferably 1,3-butadiene and / or isoprene.

Prior to the copolymerization, the polar group-containing copolymer may contain the polar group-containing vinyl compound and the following general formula (II);
M (R ⁴ ) _m (II)
(In formula (II), M represents aluminum, boron, silicon, or titanium. R ⁴ represents an aliphatic or alicyclic hydrocarbon group having 1 to 8 carbon atoms, an aliphatic or aliphatic group having 1 to 8 carbon atoms. A cyclic alkoxy group or halogens, which may be the same or different, m represents an integer of 3 or 4)
It is preferable that it is obtained by making it react with the compound represented by these, and then copolymerizing the obtained reaction product and the said conjugated diene compound.

The epoxidized conjugated diene polymer is preferably an epoxidized natural rubber and / or an epoxidized butadiene rubber.
The content of the epoxidized conjugated diene polymer is preferably 5 to 70% by mass in 100% by mass of the total rubber component, and the epoxidation rate of the epoxidized conjugated diene polymer is preferably 1 to 50% by mol. .

The rubber composition preferably includes 10 to 80% by mass of the polar group-containing copolymer in 100% by mass of the total rubber component, and 5 to 150 parts by mass of silica with respect to 100 parts by mass of the total rubber component. . Moreover, it is preferable that the said rubber composition contains 5-150 mass parts of carbon black with respect to 100 mass parts of all the rubber components.

The present invention also relates to a studless tire produced using the rubber composition.

According to the present invention, a polar group-containing copolymer obtained by copolymerizing a specific polar group-containing vinyl compound with a conjugated diene compound, and a rubber composition used in combination with an epoxidized conjugated diene copolymer, In the studless tire using this, all the performances of wear resistance, performance on ice, and steering stability on a dry road surface can be obtained in a well-balanced manner.

<Rubber composition>
The rubber composition of the present invention includes a polar group-containing copolymer and an epoxidized conjugated diene polymer.
The polar group-containing copolymer is obtained by copolymerizing a conjugated diene compound and a polar group-containing vinyl compound. Further, the polar group-containing vinyl compound has a polymerizable unsaturated bond and a polar group, and any carbon atom forming the polymerizable unsaturated bond and at least the carbon atom to which the polar group is bonded. It is a compound that binds through one carbon atom. That is, in the case where the polar group-containing vinyl compound is represented by the following formula (I), two carbon atoms having a double bond (polymerizable unsaturated bond) and X (polar group) and forming a double bond are used. The carbon atom to which R ¹ and C are bonded and the carbon atom to which X is bonded are bonded through n C (at least one carbon atom) in “— (C (R ² ) ₂ ) _n —”. doing. Furthermore, in the polar group-containing copolymer, the cis content of the double bond portion of the conjugated diene compound is 80 mol% or more.

The number of polymerizable unsaturated bonds and polar groups in the polar group-containing vinyl compound may be one each, or two or more.

Although it does not specifically limit as a polymerizable unsaturated bond, A polymerizable double bond is suitable. It does not specifically limit as a polar group, For example, -NR < ₂ > (R represents a C1-C8 hydrocarbon group and may be same or different. For example, an amino group, a monoalkylamino group. , Dialkylamino group), imino group, nitrile group, ammonium group, imide group, amide group, hydrazo group, azo group, diazo group, hydroxyl group, carboxyl group, carbonyl group, oxycarbonyl group, sulfide group, sulfonyl group, thiocarbonyl A group represented by a group, —Si (OR) _k (R) _{3 -k} (R represents a hydrocarbon group having 1 to 8 carbon atoms, and may be the same or different. In particular, a group represented by a hydroxyl group (—OH), —NR ₂ , —Si (OR) _k (R) _{3 -k} (trialkoxysilyl). Group). In this case, all of the wear resistance, the performance on ice, and the handling stability on the dry road surface can be obtained in a well-balanced manner.

In the group represented by —NR ₂ , —Si (OR) _k (R) _{3 —k} , R (hydrocarbon group having 1 to 8 carbon atoms) is not particularly limited, and is a methyl group, an ethyl group, n- Examples thereof include alkyl groups such as propyl group, isopropyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, pentyl group and hexyl group. Specific examples of the group represented by —Si (OR) _k (R) _3-k include, for example, a trimethoxysilyl group, a triethoxysilyl group, a triisopropoxysilyl group, a methyldimethoxysilyl group, and a methyldiethoxysilyl group. Group, dimethylethoxysilyl group and the like.

（式（Ｉ）中、Ｒ^１は、水素、ビニル基又は炭素数１〜３の脂肪族炭化水素基を表し、同一であっても異なっていてもよい。Ｒ^２は、水素又は炭素数１〜３の脂肪族炭化水素基を表し、同一であっても異なっていてもよい。Ｒ^３は、水素、又は炭素数１〜８の脂肪族若しくは脂環族炭化水素基を表す。Ｘは、水酸基、上記−ＮＲ_２、又は上記−Ｓｉ（ＯＲ）_ｋ（Ｒ）_３−ｋで表される基を表す。ｎは、１〜１０の整数を表す。上記Ｒ^１、Ｒ^２、Ｒ^３、該Ｒ^２が結合する炭素原子、該Ｒ^３が結合する炭素原子は、それぞれ互いに結合して環構造を形成してもよい。） As the polar group-containing vinyl compound, for example, a compound represented by the following formula (I) is preferable, and a compound represented by the following general formula (I-1) and / or (I-2) is particularly preferable. Can be used for In this case, all of the wear resistance, the performance on ice, and the handling stability on the dry road surface can be obtained in a well-balanced manner.

(In Formula (I), R ¹ represents hydrogen, a vinyl group, or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and may be the same or different. R ² represents hydrogen or one carbon atom. Represents an aliphatic hydrocarbon group having ˜3, which may be the same or different, R ³ represents hydrogen or an aliphatic or alicyclic hydrocarbon group having 1 to 8 carbon atoms, X is Represents a hydroxyl group, a group represented by —NR ₂ or the above —Si (OR) _k (R) _{3 —k} , n represents an integer of 1 to 10. The above R ¹ , R ² , R ³ , The carbon atom to which R ² is bonded and the carbon atom to which R ³ is bonded may be bonded to each other to form a ring structure.)

（式（Ｉ−１）、（Ｉ−２）中、Ｒ^１、Ｒ^２、Ｒ^３、Ｘ、ｎは、前記と同様である。）
なお、式（Ｉ−１）、（Ｉ−２）においても、式（Ｉ）と同様、環構造を形成してもよい。

(In formulas (I-1) and (I-2), R ¹ , R ² , R ³ , X, and n are the same as described above.)
In formulas (I-1) and (I-2), a ring structure may be formed as in formula (I).

In the polar group-containing vinyl compound represented by the formula (I), R ¹ is preferably hydrogen, a vinyl group or an aliphatic hydrocarbon group having 1 to 2 carbon atoms, and R ² is hydrogen from the viewpoint of ease of copolymerization. Or a C1-C2 aliphatic hydrocarbon group is preferable. From the viewpoint of good wear resistance, on-ice performance, and steering stability, R ³ is preferably hydrogen, an aliphatic or alicyclic hydrocarbon group having 1 to 4 carbon atoms. Examples of the aliphatic hydrocarbon group for R ¹ and R ² include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. Examples of the aliphatic hydrocarbon group for R ³ include an n-butyl group, an iso-butyl group, a sec-butyl group, a tert-butyl group, and a pentyl group, in addition to the aliphatic hydrocarbon groups listed for R ¹ and R ^2. Hexyl group, heptyl group, 2-ethylhexyl group, octyl group and the like. Examples of the alicyclic hydrocarbon group represented by R ³ include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclopentenyl group, and a cyclohexenyl group. R ³ may have a substituent.

From the viewpoint of ease of copolymerization, n is preferably 2 to 10, and more preferably 4 to 10. If n exceeds 10, the cost tends to increase. Incidentally, when n is an integer of 2 or more, the compounds of formula (I), - (C (R 2) 2) - may have been a unit having two or more represented, R in the same unit ² and R ² of different units may be the same group or different groups.

Examples of the polar group-containing vinyl compound represented by the formula (I) include 3-buten-1-ol, 3-methyl-3-buten-1-ol, 3-methylidene-hexane-1-ol, 5- Hexen-1-ol, 2-methyl-5-hexen-1-ol, 4-methylidenehexan-2-ol, 4-penten-1-ol, 4-methyl-4-penten-1-ol, 4 -Methylidenehexan-1-ol, 5-methyl-5-hexen-1-ol, 5-methylideneheptan-1-ol, 5-hexen-4-methyl-1-ol, 4,5-dimethyl- 5-hexen-1-ol, 4-methyl-5-methylideneheptan-1-ol, 3,4-dimethyl-5-hexen-1-ol, 3,4,5-trimethyl-5-hexene-1 -All, 3,4-Dime Ru-5-methylideneheptan-1-ol, 2-ethyl-5-methyl-5-hexen-1-ol, 3-hydroxy-6-methyl-7-octene, 6-hepten-1-ol, 6 -Methyl-6-hepten-1-ol, 6-methylideneoctane-1-ol, 7-octen-1-ol, 7-methyl-7-octen-1-ol, 7-methylidenonan-1-ol, 8 -Nonen-1-ol, 8-methyl-8-nonen-1-ol, 8-methylidenedecan-1-ol, 9-decen-1-ol, 9-methyl-9-decen-1-ol, 9-methyl Lidenundecan-1-ol, 10-undecen-1-ol, 10-methyl-10-undecen-1-ol, 10-methylidenedecan-1-ol, 7,9,10-trimethyl-10 Undecen-1-ol, 2-cyclohexyl-5-hexen-1-ol, 3-cyclohexyl-6-hepten-2-ol, 4-hexen-1-ol, 5-hepten-1-ol, 6 -Octen-1-ol, 7-nonen-1-ol, 8-decen-1-ol, 4-methyl-5-hepten-2-ol, 5-methyl-6-octen-2-ol, 6-methyl -7-nonen-2-ol, 3-methyl-4-hexen-1-ol, 4-methyl-5-hepten-1-ol, 5-methyl-6-octen-1-ol, 6-methyl -7-nonen-1-ol, 7-methyl-8-decen-1-ol, 3-methyl-4-hepten-1-ol, 4-methyl-5-octen-1-ol, 5-methyl-6 -Nonen-1-ol, 4-heptene- 1-ol, 5-octen-1-ol, 6-nonen-1-ol, 5,6-dimethyl-5-hepten-1-ol, (Z) -5-methyl-5-hepten-1-ol, (E) -7-methyl-7-nonen-2-ol and the like. Of these, 3-methyl-3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol, 6-hepten-1-ol, 9-decen-1-ol, 10-undecen-1-ol, 4-hexen-1-ol, 4-hepten-1-ol, and 5-octen-1-ol are preferred. .

Also included are compounds in which the hydroxyl groups of the hydroxyl group-containing vinyl compounds listed above are substituted with —NH ₂ , for example, 1-amino-3-butene, 1-amino-3-methyl-3-butene, 1-amino- (3-methylidene) hexane, 2-amino-4-hexene, 2-amino-4-methyl-4-hexene, 2-amino- (4-methylidene) hexane, 1-amino-4-pentene, 1-amino -4-methyl-4-penten-1-ol, 1-amino- (4-methylidene) hexane, 1-amino-5-methyl-5-hexene, 1-amino- (5-methylidene) heptane, 1 -Amino-4-methyl-5-hexene, 1-amino-4,5-dimethyl-5-hexene, 1-amino-4-methyl- (5-methylidene) heptane, 1-amino-3,4-dimethyl- 5-heki Sene, 1-amino-3,4,5-trimethyl-5-hexene, 1-amino-3,4-dimethyl- (5-methylidene) heptane, 1-amino-2-ethyl-5-methyl-5- Hexene, 3-amino-6-methyl-7-octene, 1-amino-6-heptene, 1-amino-6-methyl-6-heptene, 1-amino- (6-methylidene) octane, 1-amino- 7-octene, 1-amino-7-methyl-7-octene, 1-amino- (7-methylidene) nonane, 1-amino-8-nonene, 1-amino-8-methyl-8-nonene, 1-amino -(8-methylidene) decane, 1-amino-9-decene, 1-amino-9-methyl-9-decene, 1-amino- (9-methylidene) undecane, 1-amino-10-undecene, 1-amino -10-methyl-1 -Undecene, 1-amino-10-methylidenedecane, 1-amino-7,9,10-trimethyl-10-undecene, 1-amino-2-cyclohexyl-5-hexene, 2-amino-3-cyclohexyl -6-heptene, 1-amino-4-hexene, 1-amino-5-heptene, 1-amino-6-octene, 1-amino-7-nonene, 1-amino-8-decene, 1-amino- 4-methyl-5-heptene, 2-amino-5-methyl-6-octene, 2-amino-6-methyl-7-nonene, 1-amino-3-methyl-4-hexene, 1-amino-4 -Methyl-5-heptene, 1-amino-5-methyl-6-octene, 1-amino-6-methyl-7-nonene, 1-amino-7-methyl-8-decene, 1-amino-3- Methyl-4-heptene, 1 Amino-4-methyl-5-octene, 1-amino-5-methyl-6-nonene, 1-amino-4-heptene, 1-amino-5-octene, 1-amino-6-nonene and the like.

Further, compounds (1- (N-methylamino) -3-butene, 1- (N-methylamino) -3-methyl-3-butene, wherein the hydroxyl group of the hydroxyl group-containing vinyl compound listed above is substituted with —NHCH _{3. etc.),} - N _(CH 3) compound substituted in the ₂ (1- (N, N- dimethylamino) -3-butene, 1- (N, N- dimethylamino) -3-methyl-3-butene, etc.) Also mentioned.

Moreover, the compound which substituted the hydroxyl group of the hydroxyl group containing vinyl compound enumerated above by the group represented by the said -Si (OR) _k (R) _3-k is also mentioned, for example, 1-triethoxysilyl-3-butene 1-triethoxysilyl-3-methyl-3-butene, 1-triethoxysilyl- (3-methylidene) hexane, 2-triethoxysilyl-4-hexene, 2-triethoxysilyl-4-methyl-4- Hexene, 2-triethoxysilyl- (4-methylidene) hexane, 1-triethoxysilyl-4-pentene, 1-triethoxysilyl-4-methyl-4-penten-1-ol, 1-triethoxysilyl- (4-methylidene) hexane, 1-triethoxysilyl-5-methyl-5-hexene, 1-triethoxysilyl- (5-methylidene) heptane, 1 Triethoxysilyl-4-methyl-5-hexene, 1-triethoxysilyl-4,5-dimethyl-5-hexene, 1-triethoxysilyl-4-methyl- (5-methylidene) heptane, 1-triethoxysilyl -3,4-dimethyl-5-hexene, 1-triethoxysilyl-3,4,5-trimethyl-5-hexene, 1-triethoxysilyl-3,4-dimethyl- (5-methylidene) heptane, 1-triethoxysilyl-2-ethyl-5-methyl-5-hexene, 3-triethoxysilyl-6-methyl-7-octene, 1-triethoxysilyl-6-heptene, 1-triethoxysilyl-6 -Methyl-6-heptene, 1-triethoxysilyl- (6-methylidene) octane, 1-triethoxysilyl-7-octene, 1-triethoxysilyl -7-methyl-7-octene, 1-triethoxysilyl- (7-methylidene) nonane, 1-triethoxysilyl-8-nonene, 1-triethoxysilyl-8-methyl-8-nonene, 1-triethoxy Silyl- (8-methylidene) decane, 1-triethoxysilyl-9-decene, 1-triethoxysilyl-9-methyl-9-decene, 1-triethoxysilyl- (9-methylidene) undecane, 1-triethoxy Silyl-10-undecene, 1-triethoxysilyl-10-methyl-10-undecene, 1-triethoxysilyl-10-methylidenedecane, 1-triethoxysilyl-7,9,10-trimethyl-10-undecene, 1-triethoxysilyl-2-cyclohexyl-5-hexene, 2-triethoxysilyl-3-cyclohexyl -6-heptene, 1-triethoxysilyl-4-hexene, 1-triethoxysilyl-5-heptene, 1-triethoxysilyl-6-octene, 1-triethoxysilyl-7-nonene, 1-triethoxy Silyl-8-decene, 1-triethoxysilyl-4-methyl-5-heptene, 2-triethoxysilyl-5-methyl-6-octene, 2-triethoxysilyl-6-methyl-7-nonene, 1- Triethoxysilyl-3-methyl-4-hexene, 1-triethoxysilyl-4-methyl-5-heptene, 1-triethoxysilyl-5-methyl-6-octene, 1-triethoxysilyl-6- Methyl-7-nonene, 1-triethoxysilyl-7-methyl-8-decene, 1-triethoxysilyl-3-methyl-4-heptene, 1-triethoxysilyl -4-methyl-5-octene, 1-triethoxysilyl-5-methyl-6-nonene, 1-triethoxysilyl-4-heptene, 1-triethoxysilyl-5-octene, 1-triethoxysilyl-6 -Nonen etc. are mentioned. Further, compounds (1- (diethoxymethylsilyl) -3-butene, 1- (diethoxymethylsilyl)-(3) in which the triethoxysilyl group of the alkoxysilyl compound listed above is substituted with a diethoxymethylsilyl group. -Methylidene) hexane, etc.), compounds substituted with ethoxydimethylsilyl groups (1- (ethoxydimethylsilyl) -3-methyl-3-butene, 2- (ethoxydimethylsilyl) -4-hexene, etc.), methoxydimethylsilyl groups And the like (2-methoxydimethylsilyl-4-methyl-4-hexene, 1-methoxydimethylsilyl-4-pentene, etc.) and the like.
The said polar group containing vinyl compound may be used independently and may be used in combination of 2 or more type.

Examples of the conjugated diene compound that can be used in the present invention include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, and the like. Can be mentioned. Among these, 1,3-butadiene and isoprene are preferably used from the viewpoint of practical use such as availability of monomers. A conjugated diene compound may be used independently and may be used in combination of 2 or more type.

The polar group-containing copolymer can be produced by copolymerizing the polar group-containing vinyl compound represented by the formula (I) with the conjugated diene compound. The polymerization method is not particularly limited, and any of solution polymerization method, gas phase polymerization method, and bulk polymerization method can be used. In particular, the solution polymerization method is preferable from the viewpoint of the degree of freedom in polymer design, processability, and the like. .

When the solution polymerization method is used, the monomer concentration in the solvent is preferably 3% by mass or more, and more preferably 5% by mass or more. When the monomer concentration in the solution is less than 3% by mass, the amount of the obtained polymer is small and the cost tends to increase. The monomer concentration in the solvent is preferably 20% by mass or less, and more preferably 15% by mass or less. When the monomer concentration in the solvent exceeds 20% by mass, the solution viscosity becomes too high, stirring becomes difficult, and polymerization tends to be difficult. Moreover, any of a batch type and a continuous type may be sufficient as the superposition | polymerization form.

In the solution polymerization method, the type of catalyst is not particularly limited, but transition metal-containing compounds such as lanthanides (Nd, etc.), Ti, Co, Ni-containing compounds can be used as the catalyst. Further, Al and B-containing compounds can be used as a promoter.

The lanthanide-containing compound (such as an Nd-containing compound) is not particularly limited as long as it contains an element having an atomic number of 57 to 71. For example, carboxylate, β-diketone complex, alkoxide, phosphate, or phosphorous acid Examples thereof include salts and halides, and carboxylates, alkoxides, and β-diketone complexes are preferable from the viewpoint of ease of handling and improvement of tire performance. The Ti-containing compound includes, for example, a substituent that includes one cyclopentadienyl group, indenyl group, substituted cyclopentadienyl group, or substituted indenyl group, and is selected from a halogen, an alkoxyl group, and an alkyl group. A compound having one alkoxysilyl group is preferable from the viewpoint of improving catalyst performance and tire performance. Examples of the Co-containing compound include halides, carboxylates, β-diketone complexes, organic base complexes, and organic phosphine complexes. Examples of Ni-containing compounds include, but are not limited to, halides, carboxylates, β-diketone complexes, organic base complexes, and the like.

The Al-containing compound used as a co-catalyst is not particularly limited as long as it is an organic aluminoxane, a halogenated organoaluminum compound, an organoaluminum compound, a hydrogenated organoaluminum compound, etc., but methylaluminoxane, ethylaluminoxane, propylaluminoxane, butyl Aluminoxane, isobutylaluminoxane, octylaluminoxane, hexylaluminoxane, chloroaluminoxane, trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, diethylaluminum hydride, diisobutylaluminum hydride, dimethylaluminum chloride, diethylaluminum chloride, methylaluminum dichloride, ethyl Arminius Dichloride are preferred, they may be used in mixture. Examples of the B-containing compound include compounds containing anion species such as tetraphenylborate, tetrakis (pentafluorophenyl) borate, and (3,5-bistrifluoromethylphenyl) borate.

In the preparation of the polar group-containing copolymer, when a compound having a protonic property is used among the polar group-containing vinyl compounds, the copolymer is first deactivated in order to prevent inhibition of the polymerization reaction. It is preferable to make it. The inactivation method is not particularly limited. For example, before the copolymerization reaction of the polar group-containing vinyl compound represented by the formula (I) and the conjugated diene compound, the deactivation method is represented by the formula (I). A polar group-containing vinyl compound and the following general formula (II);
M (R ⁴ ) _m (II)
(In formula (II), M represents aluminum, boron, silicon, or titanium. R ⁴ represents an aliphatic or alicyclic hydrocarbon group having 1 to 8 carbon atoms, an aliphatic or aliphatic group having 1 to 8 carbon atoms. A cyclic alkoxy group or halogens, which may be the same or different, m represents an integer of 3 or 4)
The compound represented by these is made to react. Thereby, polar groups such as hydroxyl groups of the polar group-containing vinyl compound which is one of the inhibition factors of the polymerization reaction are inactivated, and the reaction product obtained by the reaction is copolymerized with the conjugated diene compound. Thus, the desired polar group-containing copolymer can be produced satisfactorily.

The number of carbon atoms of R ⁴ is from 1 to 6 are preferred. Examples of the aliphatic or alicyclic hydrocarbon group for R ⁴ include the same groups as those described above for R ^3. Examples of the aliphatic or alicyclic alkoxy group include the aliphatic or alicyclic hydrocarbon group. An alkoxy group corresponding to the group can be mentioned. In addition, examples of halogens for R ⁴ include chlorine, bromine, fluorine, and the like.

（式（ＩＩＩ）、（ＩＶ）中、Ｒ^５は、炭素数１〜８の脂肪族若しくは脂環族炭化水素基を表し、同一であっても異なっていてもよい。Ｒ^６は、炭素数１〜８の脂肪族若しくは脂環族炭化水素基、又は炭素数１〜８の脂肪族若しくは脂環族アルコキシ基を表し、同一であっても異なっていてもよい。Ｍ^１は、ケイ素又はチタンを表す。）
Ｒ^５、Ｒ^６の炭素数１〜８の脂肪族若しくは脂環族炭化水素基としては、例えば、上記Ｒ^４と同様の基を挙げることができる。Ｒ^６の炭素数１〜８の脂肪族若しくは脂環族アルコキシ基としては、該脂肪族若しくは脂環族炭化水素基に対応するアルコキシ基が挙げられる。 As the compound represented by the general formula (II), organometallic compounds represented by the following general formulas (III) and (IV) can be suitably used.

(In the formulas (III) and (IV), R ⁵ represents an aliphatic or alicyclic hydrocarbon group having 1 to 8 carbon atoms, and may be the same or different. R ⁶ represents the number of carbon atoms. Represents an aliphatic or alicyclic hydrocarbon group having 1 to 8 or an aliphatic or alicyclic alkoxy group having 1 to 8 carbon atoms, which may be the same or different, and M ¹ is silicon or titanium Represents.)
Examples of the aliphatic or alicyclic hydrocarbon group having 1 to 8 carbon atoms of R ^5, R ^6, for example, include the same groups as the above R ^4. Examples of the aliphatic or alicyclic alkoxy group having 1 to 8 carbon atoms of R ⁶ include an alkoxy group corresponding to the aliphatic or alicyclic hydrocarbon group.

The compound represented by the formula (III) is not particularly limited, and examples thereof include trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, dimethylaluminum chloride, diisopropylaluminum chloride, diisobutylaluminum chloride, and ethylaluminum dichloride. It is done. It does not specifically limit as a compound represented by Formula (IV), For example, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetra-n-propoxysilane, tetraisobutoxysilane, tetra-n-butoxysilane, Diethoxydimethylsilane, ethoxytrimethylsilane, diethoxydiethylsilane, ethoxytriethylsilane, tetramethoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetra-n-propoxytitanium, tetraisobutoxytitanium, tetra-n-butoxytitanium, Examples include tetra-t-butoxy titanium and tetra-sec-butoxy titanium.

Although the container used for reaction of the said polar group containing vinyl compound and the compound represented by the said general formula (II) is not specifically limited, It is preferable to carry out at least in inert gas, such as nitrogen gas and argon.

There is no restriction | limiting in particular as a method of manufacturing a polar group containing copolymer using the said catalyst 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, the reaction product of formula (I) and formula (II) The desired polar group-containing polymer can be obtained by copolymerizing the conjugated diene compound with the lanthanide, Ti, Co, Ni-containing compound as a catalyst and the Al, B-containing compound as a co-catalyst. .

The hydrocarbon solvent is preferably one having 3 to 8 carbon atoms, for example, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1-butene, isobutene, trans- Examples include 2-butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene, dichloromethane, chloroform, chlorobenzene, and the like. These may be used alone or in combination of two or more.

The polar group-containing copolymer contains 0.1 to 20% by mass of a structural unit A having 50% by mass or less of units derived from the conjugated diene compound and 50% by mass or more of units derived from the polar group-containing vinyl compound. Including 80 to 99.9% by mass of structural unit B having 60% by mass or more of units derived from the conjugated diene compound and 40% by mass or less of units derived from the polar group-containing vinyl compound, and having the polarity What has this structural unit A in the terminal part of a group containing copolymer is preferable. That is, at least the terminal part of the polar group-containing copolymer includes a structural unit A having 50% by mass or more of units derived from the polar group-containing vinyl compound, and the structural unit B having only 40% by mass or less of the unit. Is also present in the copolymer. Thereby, since the dispersibility of a silica is improved, the fall of the elasticity modulus in a high strain can be suppressed, and the steering stability on a dry road surface can be improved. Therefore, the wear resistance, on-ice performance and steering stability performance can be obtained in a more balanced manner. As such a copolymer, for example, at the end of the polymer portion I having 60% by mass or more of units derived from the conjugated diene compound and 40% by mass or less of units derived from the polar group-containing vinyl compound in a random structure, 50% by mass or less of units derived from the conjugated diene compound (preferably 5% by mass or less, more preferably 2% by mass or less, still more preferably 0% by mass) and 50% by mass or more of units derived from the polar group-containing vinyl compound. (Preferably 95% by mass or more, more preferably 98% by mass or more, and still more preferably 100% by mass). Here, when the polymer part II has 100% by mass of units derived from the polar group-containing vinyl compound, the copolymer is formed from the polar group-containing vinyl compound at the terminal of the polymer part I having a random structure. It has the block structure which becomes.

The polar group-containing copolymer having the structural units A and B is, for example, an active terminal obtained by using the transition metal-containing compound as a catalyst and copolymerizing the conjugated diene compound and the polar group-containing vinyl compound. It can be obtained by further reacting the above-mentioned polar group-containing vinyl compound with the active terminal. Specifically, in the inert organic solvent, the reaction product of the formula (I) and the formula (II) and the conjugated diene compound are copolymerized using the catalyst and the cocatalyst, thereby changing the active terminal. A copolymer solution having the following polar group-containing copolymer is obtained by further reacting the obtained copolymer solution with the reaction products of the formulas (I) and (II). Can be obtained.

In the present invention, if necessary after the copolymerization reaction, modification can be performed using a known terminal modifier for the purpose of increasing the affinity with silica as much as possible. The modification means that the active terminal portion of the polar group-containing copolymer reacts with the modifier to be terminally modified. When terminally modified, affinity with a characteristic group such as a hydroxyl group on silica is improved, so that dispersibility of silica is improved and steering stability tends to be improved.

The modifier is not particularly limited. For example, in the case of a silicon compound, 3- (N, N-dimethylamino) propyltrimethoxysilane, 3- (N, N-diethylamino) propyltrimethoxysilane, 3- (N, N -Dimethylamino) propyltriethoxysilane, 3- (N, N-diethylamino) propyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (4-pyridylethyl) triethoxysilane, N- (3- And triethoxysilylpropyl) -4,5-dihydroimidazole.

In this invention, after this reaction, alcohol etc. can be added as needed for the purpose of stopping a known anti-aging agent or polymerization reaction. By adding alcohol after the polymerization reaction, the compound represented by the formula (II) bonded to the polar group such as the hydroxyl group of the polar group-containing vinyl compound is eliminated and the polar group is generated. Will increase.

The content of the polar group-containing vinyl compound in the polar group-containing copolymer is preferably 0.03% by mass or more, more preferably 0.05% by mass or more, and still more preferably 0.1% by mass or more. The content is preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less, and particularly preferably 10% by mass or less. If it is less than 0.03% by mass, it is difficult to obtain the effect of improving the performance on ice and the steering stability performance on the dry road surface, while if it exceeds 40% by mass, the cost tends to be high.
In addition, in this invention, content of a polar group containing vinyl compound is measured by the method of the below-mentioned Example.

The polar group-containing copolymer has a cis content of the double bond portion of the conjugated diene compound in the copolymer (the cis content of the double bond in the conjugated diene compound unit in the polar group-containing copolymer) is 80 mol. % Or more, preferably 90 mol% or more. If it is less than 80 mol%, flexibility and wear resistance tend to deteriorate.
In the present invention, the amount of cis component (cis content) is a value obtained by the measurement method of Examples described later.

The weight average molecular weight Mw of the polar group-containing copolymer is preferably 1.0 × 10 ^{3 to} 2.0 × 10 ⁶ , and the lower limit is more preferably 1.0 × 10 ⁴ , and 2.0 × 10 6. ⁴ is more preferable. The upper limit is more preferably 1.0 × 10 ⁶ . If the weight average molecular weight is less than 1.0 × 10 ³ , the hysteresis loss is large and it is difficult to obtain sufficient fuel efficiency, and the wear resistance tends to be lowered. On the other hand, when it exceeds 2.0 × 10 ⁶ , workability tends to be remarkably lowered.

Moreover, Mw / Mn of the said polar group containing copolymer becomes like this. Preferably it is 4.5 or less, More preferably, it is 4.0 or less. If it exceeds 4.5, the amount of the low molecular weight component increases, so that the wear resistance tends to deteriorate.
In addition, in this invention, a weight average molecular weight (Mw) and a number average molecular weight (Mn) are measured by the method of the below-mentioned Example.

In the rubber composition of the present invention, the content of the polar group-containing copolymer is the total rubber component (a rubber component containing a polar group-containing copolymer, an epoxidized conjugated diene polymer, and other diene rubber components described later) Of 100% by mass, preferably 10% by mass or more, more preferably 15% by mass or more, and still more preferably 20% by mass or more. If it is less than 10% by mass, the effect of improving the performance on ice and the steering stability performance on a dry road surface tends to be difficult to obtain. The content is preferably 80% by mass or less, more preferably 70% by mass or less, and still more preferably 60% by mass or less. When it exceeds 80 mass%, there exists a tendency for fracture strength to deteriorate.

In the rubber composition of the present invention, an epoxidized conjugated diene polymer is used together with the polar group-containing copolymer. By using a high cis-content diene rubber (polar group-containing copolymer) having a polar group in the main chain and an epoxidized conjugated diene polymer, wear resistance and silica dispersibility can be significantly improved. As a result, the wear resistance, the performance on ice, and the handling stability on the dry road surface can be obtained in a balanced manner. Therefore, a studless tire excellent in these performances can be suitably obtained.

The epoxidized conjugated diene polymer is obtained by linking a carbon-carbon double bond portion of a conjugated diene polymer (diene rubber) by a conventionally known method such as a chlorohydrin method, a direct oxidation method, a hydrogen peroxide method, or a peracid method. For example, epoxidized natural rubber (ENR), epoxidized butadiene rubber (EBR), epoxidized styrene-butadiene rubber (ESBR), epoxidized isoprene rubber (EIR), epoxidized styrene-butadiene-sterene Examples thereof include polymers and partial hydrides thereof. Of these, ENR, EBR, and EIR are preferable, and ENR and EBR are more preferable from the viewpoint of the balance of wear resistance, performance on ice, and steering stability. These epoxidized conjugated diene polymers may be used independently and may use 2 or more types together.

The epoxidation rate of the epoxidized conjugated diene polymer is preferably in the range of 1 to 50 mol%. If it is less than 1 mol%, it becomes difficult to obtain the effect of improving the performance on ice and the steering stability performance on the dry road surface. When it exceeds 50 mol%, the glass transition point becomes too high, so that it becomes hard and the performance on ice tends to deteriorate. The lower limit of the epoxidation rate is more preferably 3 mol% or more, still more preferably 5 mol% or more, and the upper limit is more preferably 40 mol% or less, still more preferably 30 mol% or less.
The epoxidation rate is a value calculated by the following formula.
(Epoxidation rate) = (Number of epoxy groups) / (Number of epoxy groups + Number of double bond groups) × 100
In the formula, the number of double bond groups represents the number of double bonds (double bonds in the main chain, and vinyl groups and propenyl groups directly bonded to the main chain) contained in the epoxidized conjugated diene polymer. .

In the rubber composition of the present invention, the content of the epoxidized conjugated diene polymer is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass or more, based on 100% by mass of all rubber components. It is. If it is less than 5% by mass, it is difficult to obtain the effect of improving the performance on ice and the steering stability performance on the dry road surface. The content is preferably 70% by mass or less, more preferably 60% by mass or less, and still more preferably 40% by mass or less. When it exceeds 70 mass%, there exists a tendency for abrasion resistance to deteriorate.

The rubber composition of the present invention may contain a diene rubber component other than the polar group-containing copolymer and the epoxidized conjugated diene polymer. Examples of other diene rubber components include natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), Examples include acrylonitrile butadiene rubber (NBR), butyl rubber (IIR), and halogenated butyl rubber (X-IIR). Of these, NR, BR, and SBR are preferable because they exhibit a good balance of performance on ice, steering stability on dry road surfaces, and wear resistance. These rubbers may be used alone or in combination of two or more.

Silica is preferably blended in the rubber composition of the present invention. In silica compounding, the dispersibility of silica can be increased by using a polar group-containing copolymer and an epoxidized conjugated diene polymer, and a reinforcing effect can be obtained efficiently.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 50 m ² / g or more, more preferably 80 m ² / g or more. The N ₂ SA is preferably 300 m ² / g or less, and more preferably 250 m ² / g. Silica with a nitrogen adsorption specific surface area of less than 50 m ² / g has a small reinforcing effect and tends to have low wear resistance, and silica with more than 300 m ² / g has poor dispersibility, increases hysteresis loss, and lowers fuel efficiency. Tend to.
The nitrogen adsorption specific surface area of silica is a value measured by the BET method according to ASTM D3037-81.

As for the compounding quantity of a silica, 5-150 mass parts is preferable with respect to 100 mass parts of all the rubber components, a minimum is 10 mass parts and an upper limit has more preferable 100 mass parts. When the amount of silica is less than 5 parts by mass, the wear resistance tends to be insufficient, while when the amount of silica exceeds 150 parts by mass, the workability tends to deteriorate. Silica may be used alone or in combination of two or more.

In the present invention, a silane coupling agent may be used in combination with silica. Examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-triethoxysilylpropyl) disulfide, and bis (2-triethoxy). Silylethyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyl Trimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl-N, N-dimethylthiocarb Moyl tetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-triethoxysilylpropylbenzothiazolyl tetrasulfide, 3-triethoxysilyl Propyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N, N-dimethylthiocarbamoyl tetrasulfide And dimethoxymethylsilylpropylbenzothiazol tetrasulfide. Of these, bis (3-triethoxysilylpropyl) tetrasulfide and 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide are preferable from the viewpoint of improving reinforcing properties. These silane coupling agents may be used alone or in combination of two or more.

The compounding amount of the silane coupling agent is preferably 1 part by mass or more, more preferably 2 parts by mass or more with respect to 100 parts by mass of the silica. If it is less than 1 part by mass, the viscosity of the unvulcanized rubber composition tends to be high and the processability tends to deteriorate. Further, the blending amount is preferably 20 parts by mass or less, and more preferably 15 parts by mass or less. If it exceeds 20 parts by mass, the blending effect of the silane coupling agent as much as the blending amount cannot be obtained, and the cost tends to increase.

In the present invention, it is preferable to contain carbon black as a reinforcing agent. The nitrogen adsorption specific surface area _(N 2 SA) of carbon black is preferably 80~280m ² / g, the lower limit is 100 m ² / g, and more preferable upper limit is 250 meters ² / g. If the N ₂ SA of the carbon black is less than 80 m ² / g, sufficient wet grip performance cannot be obtained, and wear resistance tends to decrease. On the other hand, when it exceeds 280 m ² / g, the dispersibility is inferior and the wear resistance tends to be lowered.
In addition, the nitrogen adsorption specific surface area of carbon black is calculated | required by A method of JISK6217.

The content of carbon black is preferably 5 to 150 parts by mass with respect to 100 parts by mass of all rubber components, the lower limit is more preferably 10 parts by mass, and the upper limit is more preferably 100 parts by mass. When the content of carbon black is less than 5 parts by mass, the wear resistance tends to decrease. On the other hand, when it exceeds 150 mass parts, there exists a tendency for workability to deteriorate. Carbon black may be used alone or in combination of two or more.

In the rubber composition of the present invention, other reinforcing agents, vulcanizing agents, vulcanization accelerators, various oils, anti-aging agents, softeners, plasticizers and the like are blended for tires or general rubber compositions. Various compounding agents and additives can be blended. Moreover, the content of these compounding agents and additives can also be set to general amounts.

As a method for producing the rubber composition of the present invention, known methods can be used. For example, the above components are kneaded using a rubber kneading device such as an open roll or a Banbury mixer, and then vulcanized (crosslinked). It can be manufactured by a method or the like.

<Studless tire>
The studless tire of the present invention can be produced by a normal method using the rubber composition. That is, if necessary, the rubber composition containing the various chemicals is extruded in accordance with the shape of each member (tread, etc.) of the tire at an unvulcanized stage, and is processed on a tire molding machine by a normal method. Mold to form an unvulcanized tire. This unvulcanized tire is heated and pressurized in a vulcanizer to obtain a tire. The studless tire of the present invention thus obtained can achieve both wear resistance, performance on ice, and steering stability on a dry road surface.

The present invention will be specifically described based on examples, but the present invention is not limited to these examples.
Hereinafter, various chemicals used in the synthesis of the monomer solutions (1) to (3), the synthesis of the catalyst solution (1), and the synthesis of the polymers (1) to (5) will be described. In addition, the chemical | medical agent refine | purified according to the usual method as needed.
Cyclohexane: anhydrous cyclohexane toluene manufactured by Kanto Chemical Co., Ltd .: anhydrous toluene isopropanol manufactured by Kanto Chemical Co., Ltd .: isopropanol 5-hexen-1-ol manufactured by Kanto Chemical Co., Ltd .: 5 manufactured by Tokyo Chemical Industry Co., Ltd. -Hexen-1-ol 9-decen-1-ol: tetraisopropyl 9-decen-1-ol orthosilicate manufactured by Kanto Chemical Co., Inc .: tetraisopropylethylhexane orthosilicate manufactured by Tokyo Chemical Industry Co., Ltd. Neodymium acid: Neodymium ethyl hexanoate triisobutylaluminum manufactured by Wako Pure Chemical Industries, Ltd .: Triisobutylaluminum / hexane solution diethylaluminum chloride manufactured by Tosoh Finechem Co., Ltd. Diethylaluminum chloride manufactured by Tosoh Finechem Co., Ltd. / Hexane solution Isodibutylaluminum hydride: Tosoh Nkemu Ltd. hydrogenated iso dibutyl aluminum / toluene solution of butadiene: Takachiho Chemical Industrial Co., Ltd. 1,3-butadiene PMAO (polymethyl aluminosiloxane): Tosoh Finechem Corp. PMAO
Methanol: Methanol 2,6-tert-butyl-p-cresol (BHT) manufactured by Kanto Chemical Co., Ltd .: 2,6-tert-butyl-p-cresol manufactured by Kanto Chemical Co., Ltd.

The analysis of the obtained monomer and polymer was performed by the following method.
(Measurement of monomer purity)
The purity of the monomer was calculated from the area ratio using a gas chromatography GC2010 manufactured by Shimadzu Corporation.

(Measurement of weight average molecular weight Mw, number average molecular weight Mn)
For Mw and Mn, a GPC-8000 series apparatus manufactured by Tosoh Corporation was used, a differential refractometer was used as a detector, and the molecular weight was calibrated with standard polystyrene.

(Measurement of polar group-containing vinyl compound in polymer and cis content in butadiene unit)
The amount of the polar group-containing vinyl compound in the polymer and the cis content of the double bond in the butadiene unit were measured using a JNM-ECA series NMR apparatus manufactured by JEOL Ltd. The measurement was performed on 1 g of the synthesized polymer and intermediate, dissolved in 15 ml of toluene, slowly poured into 30 ml of methanol, purified, dried and purified.

Production Example 1 (Synthesis of Monomer Solution (1))
A 200 cc glass container was purged with nitrogen, and 50 ml of cyclohexane and 150 mmol of 5-hexen-1-ol were added and stirred. Further, 170 ml of 1M-triisobutylaluminum / hexane solution was added dropwise, and after completion of the dropwise addition, the mixture was stirred at room temperature for 30 minutes. The obtained solution was stored in a refrigerator while keeping a nitrogen atmosphere under light shielding.

Production Example 2 (Synthesis of monomer solution (2))
A 200 cc glass container was purged with nitrogen, and 50 ml of cyclohexane and 150 mmol of 9-decen-1-ol were added and stirred. Further, 170 ml of 1M-triisobutylaluminum / hexane solution was added dropwise, and after completion of the dropwise addition, the mixture was stirred at room temperature for 30 minutes. The obtained solution was stored in a refrigerator while keeping a nitrogen atmosphere under light shielding.

Production Example 3 (Synthesis of Monomer (3))
A 500 cc glass two-necked flask was purged with nitrogen, 700 mmol of tetraisopropyl orthosilicate was added and stirred, and 350 mmol of 9-decen-1-ol was added dropwise over 30 minutes on an oil bath at 70 ° C. Further, the temperature of the oil bath was raised to 85 ° C., and the mixture was stirred for 2 hours while isopropanol produced during the reaction was distilled off. Unreacted tetraisopropyl orthosilicate was distilled under reduced pressure to obtain about 120 g of monomer (3). As a result of the gas chromatographic test, the purity of the monomer was about 96%.

Production Example 4 (Synthesis of catalyst solution (1))
The 50 ml glass container was replaced with nitrogen, 8 ml of butadiene in cyclohexane solution (2.0 mol / L), 1 ml of neodymium ethylhexanoate / toluene solution (0.2 mol / L), and 8 ml of PMAO (Al: 6.8% by mass) were added. Stirring was done. After 5 minutes, 5 ml of 1M-diisobutylaluminum hydride / hexane solution was added, and further 5 minutes later, 2 ml of 1M-diethylaluminum chloride / hexane solution was added to obtain catalyst solution (1).

Production Example 5 (Synthesis of polymer (1))
A 3 L pressure-resistant stainless steel container was purged with nitrogen, and 1800 ml of cyclohexane, 75 g of butadiene, 1 ml of triisobutylaluminum / hexane solution, 0.3 mmol of monomer solution (1) were added, stirred for 10 minutes, and then 2 ml of catalyst solution (1). The mixture was added and stirred while maintaining 30 ° C. After 3 hours, a part of the reaction solution (about 50 ml) was extracted from the reaction kettle to obtain an intermediate (1) solution. Further, 0.02 mol of the monomer solution (1) was added and stirring was continued. After 3 hours, 10 ml of 0.01M-BHT / isopropanol solution was added dropwise to complete the reaction.
The reaction solution was cooled and then added to 3 L of methanol separately prepared, and the resulting precipitate was air-dried overnight and further dried under reduced pressure for 2 days to obtain a polymer (1). The yield was 99%. As a result of GPC measurement, the polymer (1) obtained had a weight average molecular weight of 55 × 10 ⁴ and Mw / Mn = 2.3.

Production Example 6 (Synthesis of polymer (2))
A 3 L pressure-resistant stainless steel container was purged with nitrogen, 1800 ml of cyclohexane, 75 g of butadiene, 1 ml of triisobutylaluminum / hexane solution, 5.9 mmol of monomer solution (1) were added, and after stirring for 10 minutes, 2 ml of catalyst solution (1) was added. The mixture was added and stirred while maintaining 30 ° C. After 3 hours, 10 ml of 0.01 M BHT / isopropanol solution was dropped into the reaction kettle to complete the reaction.
The reaction solution was cooled and then added to 3 L of methanol separately prepared. The resulting precipitate was air-dried overnight and further dried under reduced pressure for 2 days to obtain a polymer (2). The yield was 98%. As a result of GPC measurement, the polymer (2) obtained had a weight average molecular weight of 61 × 10 ⁴ and Mw / Mn = 2.6.

Production Example 7 (Synthesis of polymer (3))
A 3 L pressure-resistant stainless steel container was replaced with nitrogen, 1800 ml of cyclohexane, 75 g of butadiene, 1 ml of triisobutylaluminum / hexane solution, 3.9 mmol of monomer (3) were added, and after stirring for 10 minutes, 2 ml of catalyst solution (1) was added. The mixture was stirred while maintaining 30 ° C. After 3 hours, a part of the reaction solution (about 50 ml) was withdrawn from the reaction kettle to obtain an intermediate (3) solution. Further, 1.9 mmol of monomer (3) was added and stirring was continued. After 3 hours, 10 ml of 0.01M-BHT / isopropanol solution was added dropwise to complete the reaction.
After cooling, the reaction solution was added to 3 L of methanol separately prepared, and the resulting precipitate was air-dried overnight and further dried under reduced pressure for 2 days to obtain a polymer (3). The yield was 96%. As a result of GPC measurement, the polymer (3) obtained had a weight average molecular weight of 58 × 10 ⁴ and Mw / Mn = 2.7.

Production Example 8 (Synthesis of polymer (4))
A 3 L pressure-resistant stainless steel container was purged with nitrogen, 1800 ml of cyclohexane, 75 g of butadiene, 1 ml of triisobutylaluminum / hexane solution, 30.6 mmol of monomer solution (2) were added, and after stirring for 10 minutes, 2 ml of catalyst solution (1) was added. The mixture was added and stirred while maintaining 30 ° C. After 3 hours, a part of the reaction solution (about 50 ml) was withdrawn from the reaction kettle to obtain an intermediate (4) solution. Further, 41.7 mmol of monomer solution (2) was added and stirring was continued. After 3 hours, 10 ml of 0.01M-BHT / isopropanol solution was added dropwise to complete the reaction.
The reaction solution was cooled and then added to 3 L of methanol separately prepared. The resulting precipitate was air-dried overnight and further dried under reduced pressure for 2 days to obtain a polymer (4). The yield was 96%. As a result of GPC measurement, the polymer (4) obtained had a weight average molecular weight of 48 × 10 ⁴ and Mw / Mn = 2.9.

Production Example 9 (Synthesis of polymer (5))
A 3 L pressure-resistant stainless steel container was purged with nitrogen, 1800 ml of cyclohexane, 75 g of butadiene, 1 ml of triisobutylaluminum / hexane solution, 30.6 mmol of monomer solution (2) were added, stirred for 10 minutes, and then 2 ml of catalyst solution (1). The mixture was added and stirred while maintaining 30 ° C. After 3 hours, 10 ml of 0.01M-BHT / isopropanol solution was added dropwise to complete the reaction.
The reaction solution was cooled and then added to 3 L of methanol separately prepared. The resulting precipitate was air-dried overnight and further dried under reduced pressure for 2 days to obtain a polymer (5). The yield was 97%. As a result of GPC measurement, the polymer (5) obtained had a weight average molecular weight of 52 × 10 ⁴ and Mw / Mn = 2.8.

Table 1 shows the results (polar group-containing vinyl compound content, cis content) of H ¹ -NMR measurement performed on each of the polymers (1) to (5) and the intermediates (1), (3), and (4). Indicated.
In addition, this result also shows that the polymers (1), (3), and (4) have the structural units A and B and have the A at the terminal portion.

Production Example 10 (creation of ENR5)
To a 300 ml Erlenmeyer flask, 57 g of glacial acetic acid and 107 g of 30% hydrogen peroxide water were added, and after stirring, the mixture was allowed to stand for 24 hours while being kept at 40 ° C. in a thermostatic bath to obtain a peracetic acid solution (1). In a 1 L glass container, 300 g of natural rubber latex (trade name “HYTEX” (solid content 60%) manufactured by Nomura Trading Co., Ltd.), 300 g of distilled water, surfactant (polyoxyethylene fatty acid alcohol (carbon number C _{12 of} alcohol) C ₁₈ , cloud point 70-80 ° C.)) 3.6 g was added and cooled to 10 ° C., and 82 g of peracetic acid solution (1) was added dropwise over 10 minutes with stirring. After completion of the dropwise addition, the latex solution was stirred for 5 minutes and further poured into 1 L methanol and allowed to agglomerate. The resulting agglomerate was pulverized to about 1 cm, placed in 2 L of water, and allowed to stand overnight. The agglomerate was washed several times with water, air-dried for one day, and then dried under reduced pressure to obtain 177 g of epoxidized natural rubber (ENR5). As a result of ¹ H-NMR, the epoxidation rate was 5.1 mol%.

Examples 1-6 and Comparative Examples 1-2
Below, various chemical | medical agents used by the Example and the comparative example are demonstrated.
NR: Natural rubber (TSR 20)
BR: Hisys BR150B manufactured by Ube Industries, Ltd.
ENR5: prepared in the above production example ENR25: ENR25 manufactured by MRB (Malaysia) (epoxidation rate: 25 mol%)
Polymer: prepared in the above production example Carbon black: Show black N220 manufactured by Cabot Japan Co., Ltd. (nitrogen adsorption specific surface area (N ₂ SA): 125 m ² / g)
Silica: Ultrasil VN3 manufactured by Degussa (nitrogen adsorption specific surface area (N ₂ SA): 175 m ² / g)
Silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide) manufactured by Tegussa
Anti-aging agent: NOCRACK 6C (N-1,3-dimethylbutyl-N′-phenyl-p-phenylenediamine) manufactured by Ouchi Shinsei Chemical Co., Ltd.
Stearic acid: Stearic acid oil manufactured by NOF Corporation: Mineral oil PW-380 manufactured by Idemitsu Kosan Co., Ltd.
Zinc oxide: Zinc Hua No. 1 manufactured by Mitsui Mining & Smelting Co., Ltd. Wax: Sunnock wax manufactured by Ouchi Shinsei Chemical Co., Ltd. Sulfur: Powder sulfur vulcanization accelerator manufactured by Tsurumi Chemical Co., Ltd. 1: Eki Ouchi Noxeller CZ (N-cyclohexyl-2-benzothiazolylsulfenamide) manufactured by Chemical Industry Co., Ltd.
Vulcanization accelerator 2: Noxeller D (N, N'-diphenylguanidine) manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.

According to the formulation shown in Table 2, kneading and compounding were performed to obtain various test rubber compositions. These blends were press vulcanized at 170 ° C. for 20 minutes to obtain vulcanizates, which were evaluated on ice performance, running stability performance on dry road surfaces, and wear performance by the test methods shown below.

(Dynamic viscoelasticity test)
Using a viscoelasticity measuring tester manufactured by TS Instruments Inc., the elastic modulus (0.1% G ^* ) at a temperature of 0 ° C., a frequency of 5 Hz, an amplitude of 0.1%, and an amplitude of 40% was measured elastic modulus (40% ^{G *)} from 0.1% ^{G *} obtained by subtracting the value (ΔG ^*).
As a balance index between performance on ice and steering stability, the following formula s = (ΔG ^* ) / (0.1% G ^* )
(S is a value of 0 <s <1), and a relative value with Comparative Example 1 as 100 was used as an index. The smaller s, the better the balance between performance on ice and steering stability.

(LAT wear test)
Using a LAT tester (Laboratory Abbreviation and Skid Tester), the volume loss of each vulcanized rubber specimen was measured under the conditions of a load of 50 N, a speed of 20 km / h, and a slip angle of 5 °. The numerical values in Table 2 are relative values when the volume loss amount of Comparative Example 1 is 100. The larger the value, the better the wear resistance.

As shown in Table 2, compared with Comparative Examples 1 and 2, in Examples 1 to 6, the value of s is small and the LAT index is large. From these results, the use of a hydroxyl group-containing monomer and a copolymer having a high cis content in a butadiene unit and ENR in combination improves the balance between on-ice performance and steering stability while maintaining wear performance. It is shown that.

Claims (12)

Conjugated diene compound and a polar group-containing vinyl compound and copolymerizing polar group-containing copolymer obtained, et epoxidized conjugated diene polymer, and a rubber composition containing silica,
The polar group-containing vinyl compound has a polymerizable unsaturated bond and a polar group, and has at least one carbon atom forming the polymerizable unsaturated bond and a carbon atom to which the polar group is bonded. A compound bonded through the carbon atom of
Cis content of the double bond moiety of the conjugated diene compound state, and are more than 80 mol%,
The polar group is a group represented by a hydroxyl group, —NR ₂ , or —Si (OR) _k (R) _3-k (wherein R represents a hydrocarbon group having 1 to 8 carbon atoms and is the same. .k optionally different and represent.) der Ru rubber composition an integer of 1, 2 or 3. The polar group-containing vinyl compound has the following general formula (I):

(In Formula (I), R ¹ represents hydrogen, a vinyl group, or an aliphatic hydrocarbon group having 1 to 3 carbon atoms, and may be the same or different. R ² represents hydrogen or one carbon atom. Represents an aliphatic hydrocarbon group having ˜3, which may be the same or different, R ³ represents hydrogen or an aliphatic or alicyclic hydrocarbon group having 1 to 8 carbon atoms, X is Represents a group represented by a hydroxyl group, the —NR ₂ , or the —Si (OR) _k (R) _{3 —k} , and n represents an integer of ^{1 to} 10. The R ¹ , R ² , R ³ , The carbon atom to which R ² is bonded and the carbon atom to which R ³ is bonded may be bonded to each other to form a ring structure.)
The rubber composition of claim 1, wherein in a compound represented by. 0.1-20 mass% of structural units A in which the polar group-containing copolymer has 50 mass% or less of units derived from the conjugated diene compound and 50 mass% or more of units derived from the polar group-containing vinyl compound. Including 80 to 99.9% by mass of structural unit B having 60% by mass or more of units derived from the conjugated diene compound and 40% by mass or less of units derived from the polar group-containing vinyl compound, and having the polarity The rubber composition according to claim 1 or 2 , which has the structural unit A at a terminal portion of the group-containing copolymer. The polar group-containing copolymer further comprises the polar group-containing copolymer obtained by copolymerizing the conjugated diene compound and the polar group-containing vinyl compound using a transition metal-containing compound as a catalyst. The rubber composition according to any one of claims 1 to 3 , which is obtained by reacting a group-containing vinyl compound with the active terminal. The polar group-containing copolymer has a weight average molecular weight of 1.0 × 10 ^{3 to} 2.0 × 10 ⁶ and a content of the polar group-containing vinyl compound of 0.03 to 40% by mass. Item 5. The rubber composition according to any one of Items 1 to 4 . The rubber composition according to any one of claims 1 to 5 , wherein the conjugated diene compound is 1,3-butadiene and / or isoprene. Before the polar group-containing copolymer is copolymerized, the polar group-containing vinyl compound and the following general formula (II);
M (R ⁴ ) _m (II)
(In formula (II), M represents aluminum, boron, silicon, or titanium. R ⁴ represents an aliphatic or alicyclic hydrocarbon group having 1 to 8 carbon atoms, an aliphatic or aliphatic group having 1 to 8 carbon atoms. A cyclic alkoxy group or halogens, which may be the same or different, m represents an integer of 3 or 4)
The rubber composition according to any one of claims 1 to 6 , which is obtained by reacting a compound represented by formula (I) and then copolymerizing the obtained reaction product and the conjugated diene compound. The rubber composition according to any one of claims 1 to 7 , wherein the epoxidized conjugated diene polymer is an epoxidized natural rubber and / or an epoxidized butadiene rubber. The content of the epoxidized conjugated diene polymer is 5 to 70% by mass in 100% by mass of all rubber components, and the epoxidation rate of the epoxidized conjugated diene polymer is 1 to 50% by mol. The rubber composition according to any one of 8 to 8 . Total rubber component in 100% by mass, the comprise a polar group-containing copolymer 10 to 80 wt%, and to any one of claims 1 to 9 including 5 to 150 parts by mass of silica per 100 parts by mass of the total rubber component The rubber composition as described. The rubber composition according to any one of claims 1 to 10 , comprising 5 to 150 parts by mass of carbon black with respect to 100 parts by mass of all rubber components. Studless tire produced using the rubber composition according to any one of claims 1 to 11.