WO2018230221A1 - Rubber composition for tread, tread member, and tire - Google Patents

Abstract

Provided is a rubber composition for tread which has a continuous phase 2 and at least one discontinuous phase 4 and is obtained by vulcanizing an unvulcanized rubber composition containing a diene polymer-containing rubber component, wherein the elastic modulus E1 at 0°C of a rubber composition constituting the continuous phase 2 and the elastic modulus E2 at 0°C of a rubber composition constituting the discontinuous phase 4 satisfy 2≤(E1/E2)≤10. The rubber composition for tread exhibits excellent wet grip performance without damaging low heat generation performance. The rubber composition for tread also contains a filler 6. The filler 6 is preferably localized in the continuous phase 2.

Description

Tread rubber composition, tread member, and tire

The present invention relates to a rubber composition for a tread, a tread member, and a tire.

In the rubber composition for tires, carbon black is used from the viewpoint of rubber reinforcement.
In recent years, it is known that wet grip performance is improved by blending silica instead of carbon black that is widely blended in tire rubber compositions (see, for example, Patent Document 1).

Also, for example, studies have been made to improve wet grip performance by blending rubbers having different glass transition temperatures (Tg) (see, for example, Patent Document 2).

JP 2007-27730 A JP-A-8-27313

However, even with the technology disclosed above, the balance between reducing the rolling resistance of the tire (increasing the low loss performance) and increasing the wet grip performance is still insufficient, and the rubber composition is still wet. There was room for improvement in grip performance and low heat generation performance.

An object of the present invention is to provide a rubber composition for a tread excellent in wet grip performance without impairing low heat generation performance, and a tread member and a tire excellent in wet grip performance without impairing low loss performance.

<1> A rubber composition for a tread obtained by vulcanizing an unvulcanized rubber composition containing a rubber component containing a diene polymer, and having a continuous phase and one or more discontinuous phases, The rubber composition for a tread in which the elastic modulus E1 at 0 ° C. of the rubber composition constituting the rubber composition and the elastic modulus E2 at 0 ° C. of the rubber composition constituting the discontinuous phase satisfy 2 ≦ (E1 / E2) ≦ 10 It is a thing.

<2> The rubber composition for a tread according to <1>, wherein the glass transition temperature Tg1 of the rubber component constituting the continuous phase and the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase are Tg1> Tg2. It is.

<3> The glass transition temperature Tg1 of the rubber component constituting the continuous phase and the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase satisfy <1> or <2> satisfying Tg1−Tg2 ≧ 20 ° C. The rubber composition for tread described.

<4> The rubber composition for a tread according to any one of <1> to <3>, including a filler, wherein the filler is localized in the continuous phase.

<5> The tread rubber composition according to any one of <1> to <4>, which includes a liquid polymer, and the liquid polymer is localized in the discontinuous phase.

<6> The rubber composition for a tread according to any one of <1> to <5>, including a resin, and the resin is localized in the continuous phase.

<7> A rubber composition for a tread obtained by vulcanizing an unvulcanized rubber composition containing a rubber component containing a diene polymer and having a continuous phase and one or more discontinuous phases, The filler is localized in the continuous phase, and the glass transition temperature Tg1 of the rubber component constituting the continuous phase and the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase are Tg1> Tg2 It is the rubber composition for tread which is.

<8> The tread according to <7>, wherein the glass transition temperature Tg1 of the rubber component constituting the continuous phase and the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase satisfy Tg1-Tg2 ≧ 20 ° C. It is a rubber composition.

<9> The tread rubber composition according to <7> or <8>, which includes a liquid polymer, and the liquid polymer is localized in the discontinuous phase.

<10> The rubber composition for a tread according to any one of <7> to <9>, including a resin, and the resin is localized in the continuous phase.

<11> The elastic modulus E1 at 0 ° C. of the rubber composition constituting the continuous phase and the elastic modulus E2 at 0 ° C. of the rubber composition constituting the discontinuous phase are 2 ≦ (E1 / E2) ≦ 10 The rubber composition for a tread according to any one of <7> to <10>, wherein

<12> The rubber composition for a tread according to any one of <1> to <11>, wherein the domain diameter of the discontinuous phase is 50 to 500 nm.

<13> Any of <4> to <12>, wherein the ratio of the filler contained in the continuous phase among all the fillers is greater than the ratio of the diene polymer contained in the continuous phase among all the diene polymers. It is a rubber composition for tread as described in any one.

<14> In the total mass of the liquid polymer, the amount of the liquid polymer contained in the discontinuous phase is more than 50 mass% and 100 mass% or less. <5>, <6>, and <9> to <13> It is a rubber composition for treads as described in any one.

<15> The total amount of the resin according to any one of <6> and <10> to <14>, wherein the amount of the resin contained in the continuous phase is more than 50% by mass and 100% by mass or less. It is a rubber composition for treads.

<16> A tread member using the tread rubber composition according to any one of <1> to <15>.

<17> A tire using the tread member according to <16>.

According to the present invention, it is possible to provide a rubber composition for a tread excellent in wet grip performance without impairing low heat generation performance, and a tread member and tire excellent in wet grip performance without impairing low loss performance.

FIG. 1 is a schematic diagram showing a sea (continuous phase) -island (discontinuous phase) structure of a rubber composition for a tread of the present invention including a continuous phase and a discontinuous phase.

Hereinafter, embodiments of the present invention will be described. These descriptions are intended to exemplify the present invention and do not limit the present invention in any way.
In the present invention, when simply referred to as “rubber composition”, it means a vulcanized rubber composition, and the rubber composition before vulcanization is referred to as “unvulcanized rubber composition”. Further, the rubber composition for tread may be simply referred to as “rubber composition”.
In the present invention, the “rubber component” is a component that contains at least a diene polymer and does not contain a filler (the content of the filler is 0% by mass).
In addition to the diene polymer, the rubber component may contain a wax, an anti-aging agent, a zinc compound, sulfur and the like, if necessary. The rubber component is contained in the unvulcanized rubber composition and is not contained in the vulcanized rubber composition.

<Rubber composition for tread>
The rubber composition for a tread of the present invention includes the rubber composition for a tread of the first aspect of the present invention and the rubber composition for a tread of the second aspect of the present invention. Hereinafter, the matter described simply as “the rubber composition for a tread of the present invention” is common to the rubber composition for a tread of the first invention and the rubber composition for a tread of the second invention.

The rubber composition for a tread according to the first aspect of the present invention is a tread having a continuous phase and one or more discontinuous phases obtained by vulcanizing an unvulcanized rubber composition containing a rubber component containing a diene polymer. The elastic modulus E1 at 0 ° C. of the rubber composition constituting the continuous phase and the elastic modulus E2 at 0 ° C. of the rubber composition constituting the discontinuous phase are 2 ≦ (E1 / E2) ≦ 10 is satisfied.
That is, the rubber composition of the first invention is a vulcanized rubber composition obtained by vulcanizing an unvulcanized rubber composition containing a rubber component, and each of the continuous phase and the discontinuous phase of the vulcanized rubber composition The elastic modulus E at 0 ° C. of the rubber composition constituting the phase satisfies the above formula.
The unvulcanized rubber composition constituting the rubber composition for a tread of the first aspect of the present invention may contain a filler. In this case, the unvulcanized rubber composition comprises a rubber component and a filler.

An example of the phase structure of the rubber composition of the first invention will be described with reference to the schematic diagram shown in FIG.
The first rubber composition of the present invention includes an incompatible rubber composition, and as shown in FIG. 1, a continuous phase 2 and a non-continuous phase 4 that are incompatible with each other are composed of sea (continuous phase 2)- It has an island (non-continuous phase 4) structure. Since the discontinuous phase 4 is dispersed in the continuous phase 2, it may be referred to as a dispersed phase.
In the rubber composition of the first invention, the elastic modulus E1 at 0 ° C. of the rubber composition constituting the continuous phase 2 and the elastic modulus E2 at 0 ° C. of the rubber composition constituting the discontinuous phase 4 are 2 ≦ (E1 / E2) ≦ 10 is satisfied. That is, the continuous phase 2 is harder than the discontinuous phase 4 in the range where E1 / E2 is 2 to 10, the discontinuous phase 4 is soft, and the hard continuous phase 2 includes the micro soft discontinuous phase 4. It has a structure. It is considered that the rubber composition for a tread has a sea-island structure with a difference in elastic modulus, whereby distortion is increased and wet grip performance is improved.
As will be described later, the rubber composition of the first present invention preferably contains a filler 6, and the filler 6 is preferably localized in the continuous phase 2.
Here, “the filler 6 is localized in the continuous phase 2” means that the proportion of the amount of the filler in the continuous phase 2 among all the fillers is the diene type in the continuous phase 2 among all the diene polymers. It means more than the proportion of polymer.

In the rubber composition for a tread according to the first aspect of the present invention, the ratio between the elastic modulus E1 at 0 ° C. of the rubber composition constituting the continuous phase and the elastic modulus E2 at 0 ° C. of the rubber composition constituting the discontinuous phase ( E1 / E2) is 2-10. From the viewpoint of further improving the low heat generation performance and improving the wet grip performance, E1 / E2 is preferably 3 to 10.

The rubber composition for a tread of the second aspect of the present invention is for a tread having a continuous phase and one or more discontinuous phases obtained by vulcanizing an unvulcanized rubber composition containing a rubber component containing a diene polymer. A rubber composition comprising a filler, the filler being localized in the continuous phase, the glass transition temperature Tg1 of the rubber component constituting the continuous phase, and the rubber component constituting the discontinuous phase The glass transition temperature Tg2 of Tg1> Tg2.
In the present invention, the “rubber component constituting the continuous phase” is a rubber component contained in the unvulcanized rubber composition when the rubber composition constituting the continuous phase is an unvulcanized rubber composition. . Similarly, the “rubber component constituting the discontinuous phase” is a rubber component contained in the unvulcanized rubber composition when the rubber composition constituting the discontinuous phase is an unvulcanized rubber composition. is there.
Hereinafter, the rubber component constituting the continuous phase may be referred to as “rubber component R1”, and the rubber component constituting the discontinuous phase may be referred to as “rubber component R2”.
That is, in the second present invention, the glass transition temperature (Tg1) of the rubber component R1 is higher than the glass transition temperature (Tg2) of the rubber component R2.

An example of the phase structure of the rubber composition of the second invention will be described with reference to the schematic diagram shown in FIG.
The rubber composition of the second invention includes an incompatible rubber composition, and as shown in FIG. 1, a continuous phase 2 and a non-continuous phase 4 that are incompatible with each other are composed of sea (continuous phase 2)- It has an island (non-continuous phase 4) structure. Since the discontinuous phase 4 is dispersed in the continuous phase 2, it may be referred to as a dispersed phase.
The rubber composition of the second invention is a rubber composition for a tread having a continuous phase 2 and one or more discontinuous phases 4 obtained by vulcanizing an unvulcanized rubber composition containing a rubber component. The filler 6 is contained in the continuous phase 2 and the glass transition temperature Tg1 of the rubber component constituting the continuous phase 2 and the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase 4 are , Tg1> Tg2.

By making the glass transition temperature of the rubber component constituting the continuous phase 2 larger than the glass transition temperature of the rubber component constituting the continuous phase 4, the continuous phase 2 becomes harder than the discontinuous phase 4, and the rubber of the present invention The composition has a structure including a micro soft discontinuous phase 4 in a hard continuous phase 2.
Further, the rubber composition of the second aspect of the present invention includes the filler 6 and the filler 6 is localized in the continuous phase 2. Since the filler 6 is localized in the continuous phase 2, an elastic difference due to the filler 6 occurs between the continuous phase 2 and the discontinuous phase 4 in addition to the elastic difference due to the rigidity of the rubber component. .
Here, “the filler 6 is localized in the continuous phase 2” means that the proportion of the amount of the filler in the continuous phase 2 among all the fillers is the diene type in the continuous phase 2 among all the diene polymers. It means more than the proportion of polymer.

Thus, it is considered that the continuous phase 2 and the discontinuous phase 4 of the rubber composition of the second invention have a sea-island structure with a difference in elasticity, so that distortion increases and wet grip performance is improved.
Hereinafter, description will be made with the reference numerals omitted.

From the viewpoint of making the continuous phase harder than the discontinuous phase, the ratio between the elastic modulus E1 at 0 ° C. of the rubber composition constituting the continuous phase and the elastic modulus E2 at 0 ° C. of the rubber composition constituting the discontinuous phase ( E1 / E2) is preferably 2 to 10. By giving a difference in elastic modulus with E1 / E2 in such a range, the low heat generation performance of the rubber composition of the second invention can be further enhanced, and the wet grip performance can be further improved. E1 / E2 is preferably 3 to 10.

In the first and second aspects of the present invention, the elastic modulus at 0 ° C. of the rubber composition constituting each phase is obtained by, for example, cutting the rubber composition with a microtome to obtain a sample, and obtaining the smooth surface of the obtained sample, Using an atomic force microscope (AFM), it can be measured by measuring in a measurement range of 2 μm × 2 μm.
Specifically, a sample fixed on a fixed base at 0 ° C. is pushed in using a cantilever, and a force curve is measured. From the curve obtained from the measurement, analysis is performed based on the Hertz theory, and the elastic modulus E of each phase is measured as Young's modulus.
As the atomic force microscope, for example, MFP-3D manufactured by ASYLUM RESEARCH can be used.
Distinguishing between the smooth surface of the sample and where it is the continuous phase and where it is the discontinuous phase, the rubber composition constituting each phase is cut by a microtome to obtain a sample, and the smooth surface of the obtained sample is obtained. By observing with an atomic force microscope and ternary image observation of the atomic force microscope, it is possible to determine a phase in which domains are connected throughout as a continuous phase and a phase other than that as a discontinuous phase.
The elastic modulus E of each phase is obtained by averaging the values measured at any five locations selected for random operation in the measurement range of 2 μm × 2 μm for the continuous phase. For the discontinuous phase, one domain is measured per domain for any five domains selected in a random manner within a measurement range of 2 μm × 2 μm, and the obtained five values are averaged.

The domain diameter of the discontinuous phase is preferably 50 to 500 nm.
When the domain diameter of the discontinuous phase is 50 nm or more, a region of an island portion where strain is applied is secured, and the wet grip performance is easily improved. On the other hand, when the domain diameter of the discontinuous phase is 500 nm or less, it is easy to maintain the hardness of the entire rubber composition, and it is easy to maintain low heat generation performance.
From the viewpoint of further improving wet grip performance and low heat generation performance, the domain diameter of the discontinuous phase is more preferably 80 to 400 nm, and still more preferably 100 to 300 nm.

The domain diameter (region width) of the discontinuous phase is measured by cutting the rubber composition constituting each phase with a microtome to obtain a sample, and observing the smooth surface of the obtained sample with an atomic force microscope can do.
After ternarizing the image obtained by the atomic force microscope, if the domain is circular, the diameter of the circle is measured as the domain diameter. If the domain is irregular, such as a mottled pattern, the longitudinal direction of each domain ( The maximum length of the domain in the direction orthogonal to the direction in which the linear distance between the ends in one domain is the longest) is measured as the domain diameter.

As will be described later, the rubber composition of the present invention preferably contains a filler. When the rubber composition contains a filler, the range of the discontinuous phase is determined as follows.
In the image obtained by the atomic force microscope, when the filler exists on the boundary line between the discontinuous phase and the continuous phase, the range in which the filler portion is extracted from the discontinuous phase is determined as the range of the discontinuous phase. . On the other hand, when a filler is contained inside the boundary line of the discontinuous phase, the discontinuous phase is discontinuous in the boundary line between the discontinuous phase and the continuous phase without considering the presence of the filler. The domain diameter is measured as the phase range.
Further, it is preferable that the discontinuous phase does not include a domain having a domain diameter of 5 μm or more.

[Rubber component]
As described above, the rubber composition of the first invention has a ratio (E1 / E2) of the elastic modulus E at 0 ° C. of the rubber composition constituting each phase of the continuous phase and the discontinuous phase to 2 to 2. As 10, the difference in elastic modulus between the continuous phase and the discontinuous phase can be balanced to achieve a balance between low heat generation performance and wet grip performance.
Here, the rubber composition of the first present invention is a vulcanized rubber composition obtained by vulcanizing an unvulcanized rubber composition containing a rubber component, and a glass transition temperature Tg1 of the rubber component constituting the continuous phase; When the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase is Tg1> Tg2, it is easy to give a difference in elastic modulus between the continuous phase and the discontinuous phase of the rubber composition after vulcanization.

The rubber composition of the second invention includes a filler, the filler is localized in the continuous phase, and the glass transition temperature Tg1 of the rubber component R1 constituting the continuous phase is a rubber constituting the discontinuous phase. The temperature is higher than the glass transition temperature Tg2 of the component R2, thereby providing an elastic difference between the continuous phase and the discontinuous phase, and a balance between low heat generation performance and wet grip performance can be achieved.

Furthermore, from the viewpoint of increasing the difference in elastic modulus between the continuous phase and the discontinuous phase of the rubber composition and improving the low heat generation performance and the wet grip performance, the glass transition temperature Tg1 of the rubber component R1 constituting the continuous phase, The glass transition temperature Tg2 of the rubber component R2 constituting the continuous phase preferably satisfies Tg1−Tg2 ≧ 20 ° C. “Tg1−Tg2” may be referred to as ΔTg.
In the rubber composition of the first invention, ΔTg is preferably 80 ° C. or less, more preferably 25 to 75 ° C., and more preferably 30 to 70 ° C. from the viewpoint of improving low heat generation performance and wet grip performance. More preferably.
In the rubber composition of the second invention, ΔTg is preferably 75 ° C. or less, more preferably 25 to 70 ° C., and more preferably 30 to 67 ° C. from the viewpoint of improving low heat generation performance and wet grip performance. More preferably.

In the rubber composition of the present invention, the rubber component contains a diene polymer.
The diene polymer may be a homopolymer of a diene monomer or may be a copolymer of a diene monomer and another monomer.
Examples of the diene polymer include natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), and modified ones thereof.
The rubber component R1 constituting the continuous phase and the rubber component R2 constituting the discontinuous phase are incompatible with each other on the order of submicrons, and when the unvulcanized rubber composition is prepared, the rubber component R1 and the rubber component When R2 is mixed, phase separation occurs. The rubber components R1 and R2 may be incompatible with each other on the order of submicrons, and may be compatible with the naked eye. In order to observe the incompatibility on the order of submicron, for example, using FIB / SEM, the region of 4 μm × 4 μm of the rubber composition is observed. The method of judging is mentioned.

An example of a method for selecting rubber components that are not compatible with each other is to use a difference in solubility parameter (SP value; Solubility Parameter) of the rubber component. The greater the difference in SP value, the more incompatible rubber components, and the rubber component whose content in the unvulcanized rubber composition generally exceeds 50% by volume is the continuous phase.
Regarding the SP value difference, the difference (| SP1-SP2 |) between the SP value (SP1) of the rubber component R1 and the SP value (SP2) of the rubber component R2 is preferably 0.15 or more.
The SP value of the rubber component can be calculated according to the Fedors method. The unit of SP value is (cal / cm ³ ) ^0.5 .

(Rubber component R1 constituting the continuous phase)
The rubber component R1 is a component listed as a rubber component that can be included in the unvulcanized rubber composition, and can constitute a continuous phase in which E1 / E2 falls within the range of 2 to 10 after vulcanization. It does not restrict | limit, 1 type may be sufficient and 2 or more types may be used. For example, it can be selected in consideration of the relationship between the glass transition temperatures Tg1 and Tg2 described above.
However, when two or more types of diene polymers (including modified diene polymers; the same applies hereinafter) are used in the rubber component R1, the diene systems in the rubber component R2 that are compatible with each other and constitute a discontinuous phase. An incompatible diene polymer is used as the polymer. When the diene polymer in the rubber component R2 is two or more types of diene polymers, any of the diene polymers in the rubber component R1 is any of the diene polymers in the rubber component R2. An incompatible diene polymer is used.

Since the continuous phase is required to be a harder phase than the discontinuous phase, the glass transition temperature Tg1 of the rubber component R1 is preferably −70 to −10 ° C., and −65 to −15 ° C. Is more preferable, and is more preferably −64 to −20 ° C.
The glass transition temperature (Tg) of the rubber component R1, the rubber component R2 described later, and the liquid polymer can be measured by differential scanning calorimetry (DSC). For example, it can be measured using a differential scanning calorimeter manufactured by TA Instruments under the condition of a sweep rate of 5 to 10 ° C./min.

As described above, the rubber composition of the first invention preferably contains a filler, and the filler is continuous from the viewpoint of making the continuous phase harder and increasing the difference in elastic modulus from the discontinuous phase. It is preferable to be localized in the phase.
The rubber composition of the second aspect of the present invention contains a filler, and since the filler is localized in the continuous phase, the continuous phase is hard and has a large elastic difference from the discontinuous phase.
In the present invention, as a technique for localizing the filler in the continuous phase, the polarity of the diene polymer and the filler can be used, or the diene polymer can be used as a modified functional group having an interaction property with the filler. And a diene polymer having a group (referred to as a modified diene polymer). Among these, from the viewpoint of increasing the proportion of the filler present in the continuous phase, it is preferable to use a modified diene polymer as the diene polymer.

There is no restriction | limiting in particular as a modified functional group in a modified | denatured diene type polymer, According to the objective, it can select suitably. Suitable examples of the modified functional group include a modified functional group having an interaction property with a filler described later. Increases the interaction with the filler, making it easier to localize the filler in the continuous phase.
Here, the “modified functional group having an interaction property with the filler” means, for example, a covalent bond between the modified functional group and the surface of the filler (for example, silica); intermolecular force (ion-dipolar) This means a functional group capable of forming intermolecular forces such as dipole interactions, dipole-dipole interactions, hydrogen bonds, and van der Waals forces. There is no restriction | limiting in particular as a modified functional group with high interaction property with a filler (for example, silica), For example, a nitrogen-containing functional group, a silicon-containing functional group, an oxygen-containing functional group etc. are mentioned suitably.

The modifying agent for obtaining the modified diene polymer can be appropriately selected from the above-mentioned known modifying agents having a modified functional group.

The modifying agent is preferably a modifying agent having at least one atom selected from a silicon atom, a nitrogen atom and an oxygen atom.

It is preferable that the modifying agent is at least one selected from the group consisting of an alkoxysilane compound, a hydrocarbyloxysilane compound, and a combination thereof because of high interaction with a filler (for example, silica).

The alkoxysilane compound is not particularly limited, but is more preferably an alkoxysilane compound represented by the following general formula (I).
R ¹ _a -Si- (OR ² ) _4-a (I)
In the general formula (I), R ¹ and R ² 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, Is an integer of 0 to 2, and when there are a plurality of OR ² , each OR ² may be the same as or different from each other, and no active proton is contained in the molecule.

Specific examples of the alkoxysilane compound represented by the general formula (I) include N- (1,3-dimethylbutylidene) -3-triethoxysilyl-1-propanamine, tetramethoxysilane, tetraethoxysilane, tetra -N-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraisobutoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxy Silane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltripropoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltripropoxy Silane, propyltriisopropoxysilane, butyltrimethoxysilane, butyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyltrimethoxysilane, methylphenyldimethoxysilane, dimethyldiethoxysilane, vinyltrimethoxysilane, vinyltri Examples thereof include ethoxysilane and divinyldiethoxysilane. Among these, N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine, tetraethoxysilane, methyltriethoxysilane, and dimethyldiethoxysilane are preferable. An alkoxysilane compound may be used individually by 1 type, and may be used in combination of 2 or more type.

The hydrocarbyloxysilane compound is preferably a hydrocarbyloxysilane compound represented by the following general formula (II).

In the general formula (II), n1 + n2 + n3 + n4 = 4 (where n2 is an integer of 1 to 4, n1, n3 and n4 are integers of 0 to 3), and A ¹ is a saturated cyclic tertiary amine compound Residue, unsaturated cyclic tertiary amine compound residue, ketimine residue, nitrile group, (thio) isocyanate group, (thio) epoxy group, isocyanuric acid trihydrocarbyl ester group, carbonic acid dihydrocarbyl ester group, nitrile group, pyridine Group, (thio) ketone group, (thio) aldehyde group, amide group, (thio) carboxylic acid ester group, metal salt of (thio) carboxylic acid ester, carboxylic acid anhydride residue, carboxylic acid halogen compound residue, and It is at least one functional group selected from a primary or secondary amino group having a hydrolyzable group or a mercapto group, and n4 is 2 or more. The case may be the same or different, A ¹ may be a divalent group bonded to Si to form a cyclic structure, R ²¹ is an aliphatic monovalent having 1 to 20 carbon atoms Or an alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and when n1 is 2 or more, they may be the same or different, and R ²³ has 1 to 20 carbon atoms. A monovalent aliphatic or alicyclic hydrocarbon group, a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or a halogen atom, and when n3 is 2 or more, they may be the same or different, R ²² is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, each of which contains a nitrogen atom and / or a silicon atom. May be contained, and when n2 is 2 or more, they are the same or different from each other Even if well, or forms a ring together, R ²⁴ is a divalent 1-20 carbon atoms aliphatic or alicyclic hydrocarbon group or a divalent C 6-18 When it is an aromatic hydrocarbon group and n4 is 2 or more, they may be the same or different.

The hydrolyzable group in the primary or secondary amino group having a hydrolyzable group or the mercapto group having a hydrolyzable group is preferably a trimethylsilyl group or a tert-butyldimethylsilyl group, particularly preferably a trimethylsilyl group.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound represented by the following general formula (III).

In the general formula (III), p1 + p2 + p3 = 2 (wherein p2 is an integer of 1 to 2, p1 and p3 are integers of 0 to 1), A ² is NRa (Ra is a monovalent A hydrocarbon group, a hydrolyzable group or a nitrogen-containing organic group), or sulfur, and R ²⁵ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or 6 to 6 carbon atoms. 18 is a monovalent aromatic hydrocarbon group, and R ²⁷ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. Or a halogen atom, and R ²⁶ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or a nitrogen-containing organic group. Any of them may contain a nitrogen atom and / or a silicon atom, and p2 is 2 May be the same or different from each other, or together form a ring, and R ²⁸ is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a carbon number 6 to 18 divalent aromatic hydrocarbon groups. As the hydrolyzable group, a trimethylsilyl group or a tert-butyldimethylsilyl group is preferable, and a trimethylsilyl group is particularly preferable.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound represented by the following general formula (IV) or (V).

In the general formula (IV), q1 + q2 = 3 (where q1 is an integer of 0 to 2, q2 is an integer of 1 to 3), and R ³¹ is a divalent aliphatic having 1 to 20 carbon atoms. Or an alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, wherein R ³² and R ³³ are each independently a hydrolyzable group, a monovalent fatty acid having 1 to 20 carbon atoms. An aliphatic or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and R ³⁴ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a carbon number A monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, which may be the same or different when q1 is 2, and R ³⁵ is a monovalent aliphatic or alicyclic hydrocarbon having 1 to 20 carbon atoms Group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and when q2 is 2 or more, May be different.

In general formula (V), r1 + r2 = 3 (wherein r1 is an integer of 1 to 3 and r2 is an integer of 0 to 2), and R ³⁶ is a divalent aliphatic having 1 to 20 carbon atoms. Or an alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and R ³⁷ is a dimethylaminomethyl group, dimethylaminoethyl group, diethylaminomethyl group, diethylaminoethyl group, methylsilyl (methyl) Aminomethyl group, methylsilyl (methyl) aminoethyl group, methylsilyl (ethyl) aminomethyl group, methylsilyl (ethyl) aminoethyl group, dimethylsilylaminomethyl group, dimethylsilylaminoethyl group, monovalent fat having 1 to 20 carbon atoms An aliphatic or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and when r1 is 2 or more, they may be the same or different. Even if well, R ³⁸ is a hydrocarbyloxy group having 1 to 20 carbon atoms, monovalent 1-20 carbon atoms aliphatic or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon having 6 to 18 carbon atoms And when r2 is 2, they may be the same or different.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound having two or more nitrogen atoms represented by the following general formula (VI) or (VII). As a result, the filler is easily localized in the continuous phase, and the low heat generation performance and the wet grip performance can be further improved.

In the general formula (VI), TMS is a trimethylsilyl group, R ⁴⁰ is a trimethylsilyl group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic group having 6 to 18 carbon atoms. R ⁴¹ is a hydrocarbyloxy group having 1 to 20 carbon atoms, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic carbon atom having 6 to 18 carbon atoms. R ⁴² is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.

In general formula (VII), TMS is a trimethylsilyl group, and R ⁴³ and R ⁴⁴ are each independently a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a divalent aliphatic group having 6 to 18 carbon atoms. R ⁴⁵ is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, R ⁴⁵ may be the same or different.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound represented by the following general formula (VIII).

In general formula (VIII), r1 + r2 = 3 (wherein r1 is an integer of 0 to 2 and r2 is an integer of 1 to 3), TMS is a trimethylsilyl group, and R ⁴⁶ has 1 to 3 carbon atoms. 20 a divalent aliphatic or alicyclic hydrocarbon group or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, wherein R ⁴⁷ and R ⁴⁸ are each independently a monovalent group having 1 to 20 carbon atoms. An aliphatic or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. A plurality of R ⁴⁷ or R ⁴⁸ may be the same or different.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound represented by the following general formula (IX).

In general formula (IX), Y is a halogen atom, and R ⁴⁹ is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms. R ⁵⁰ and R ⁵¹ are each independently a hydrolyzable group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. R ⁵⁰ and R ⁵¹ are bonded to form a divalent organic group, and R ⁵² and R ⁵³ are each independently a halogen atom, a hydrocarbyloxy group, or a group having 1 to 20 carbon atoms. A monovalent aliphatic or alicyclic hydrocarbon group or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms; R ⁵⁰ and R ⁵¹ are preferably hydrolyzable groups, and the hydrolyzable group is preferably a trimethylsilyl group or a tert-butyldimethylsilyl group, and particularly preferably a trimethylsilyl group.

The hydrocarbyloxysilane compound represented by the general formula (II) is preferably a hydrocarbyloxysilane compound having a structure represented by the following general formulas (X) to (XIII).

In the general formulas (X) to (XIII), the symbols U and V are integers satisfying 0 to 2 and U + V = 2, respectively. R ⁵⁴ to R ⁵⁶ , R ⁶⁰ to R ⁶⁶ , R ⁶⁸ to R ⁷⁰ , R ⁷² to R ⁷⁶ , R ⁷⁹ , R ⁸⁰ , R ⁸² , R ⁸³ , and R ^{85 in the} general formulas (X) to (XIII) R ⁹¹ may be the same or different and each represents a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. In the general formulas (X) to (XIII), R ⁵⁷ to R ⁵⁹ , R ⁶⁷ , R ⁷¹ , R ⁷⁷ , R ⁷⁸ , R ⁸¹ , R ⁸⁴ , and R ⁹² may be the same or different and have 1 carbon atom. A divalent aliphatic or alicyclic hydrocarbon group of ˜20 or a divalent aromatic hydrocarbon group of 6 to 18 carbon atoms. In the general formula (XIII), α and β are integers of 0 to 5.

Among the compounds of the general formulas (X) to (XII), N1, N1, N7-tetramethyl-4-((trimethoxysilyl) methyl) -1,7heptane, 2-((hexyl-dimethoxysilyl) methyl ) -N1, N1, N3, N3-2-pentamethylpropane-1,3-diamine, N1- (3- (dimethylamino) propyl-N3, N3-dimethyl-N1- (3- (trimethoxysilyl) propyl ) Propane-1,3-diamine, 4- (3- (dimethylamino) propyl) -N1, N1, N7, N7-tetramethyl-4-((trimethoxysilyl) methyl) heptane-1,7-diamine Is preferred.

Among the compounds of the general formula (XIII), N, N-dimethyl-2- (3- (dimethoxymethylsilyl) propoxy) ethanamine, N, N-bis (trimethylsilyl) -2- (3- (trimethoxysilyl) propoxy Ethanamine, N, N-dimethyl-2- (3- (trimethoxysilyl) propoxy) ethanamine, and N, N-dimethyl-3- (3- (trimethoxysilyl) propoxy) propan-1-amine are preferred.

The hydrocarbyloxysilane compounds represented by the general formulas (II) to (XIII) are preferably used as a modifier for the rubber component R1, but as a modifier for the rubber component R2 and any other rubber component or polymer component. It may be used.

The hydrocarbyloxysilane compounds represented by the general formulas (II) to (XIII) are preferably alkoxysilane compounds.

Suitable modifiers for obtaining the modified diene polymer by anionic polymerization include, for example, 3,4-bis (trimethylsilyloxy) -1-vinylbenzene, 3,4-bis (trimethylsilyloxy) benzaldehyde, 3,4 And at least one compound selected from -bis (tert-butyldimethylsilyloxy) benzaldehyde, 2-cyanopyridine, 1,3-dimethyl-2-imidazolidinone and 1-methyl-2-pyrrolidone.

The modifier is preferably an amide portion of a lithium amide compound used as a polymerization initiator in anionic polymerization. Examples of such lithium amide compounds include lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene imide, lithium dodecamethylene imide, lithium dimethylamide, lithium diethylamide, lithium dibutylamide, and lithium dipropyl. Amide, lithium diheptylamide, lithium dihexylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium-N-methylpiverazide, lithium ethylpropylamide, lithium ethylbutyramide, lithium ethylbenzylamide, lithium methyl Phenethylamide and combinations thereof are mentioned. For example, the modifying agent that becomes the amide portion of lithium hexamethyleneimide is hexamethyleneimine, the modifying agent that becomes the amide portion of lithium pyrrolidide is pyrrolidine, and the modifying agent that becomes the amide portion of lithium piperidide is piperidine. .

Suitable modifiers for obtaining a modified diene polymer by coordination polymerization include, for example, at least one compound selected from 2-cyanopyridine and 3,4-ditrimethylsilyloxybenzaldehyde.

Suitable modifiers for obtaining a modified diene polymer by emulsion polymerization include, for example, at least one compound selected from 3,4-ditrimethylsilyloxybenzaldehyde and 4-hexamethyleneiminoalkylstyrene. These modifiers preferably used in emulsion polymerization are preferably copolymerized at the time of emulsion polymerization as monomers containing nitrogen atoms and / or silicon atoms.

There is no restriction | limiting in particular as a modification rate in a modified diene polymer, According to the objective, it can select suitably. For example, the modification rate is preferably 30% or more, more preferably 35% or more, and particularly preferably 70% or more. Thereby, a filler (especially silica) comes to exist selectively by a continuous phase, and can improve low heat generation performance and wet grip performance.

An example of the modified diene polymer as the rubber component R1 will be described.
First, a copolymer of styrene and 1,3-butadiene (microstructure: 10% by mass of styrene / 40% by mass of vinyl bonds derived from 1,3-butadiene, base molecular weight (polystyrene conversion): 180,000). A polymer was prepared, and modified with N, N-bis (trimethylsilyl) -3- [diethoxy (methyl) silyl] propylamine in a state where the terminal was an anion, and a modified diene polymer (modification rate: 70). %, Weight average molecular weight (Mw): 200,000).

(Rubber component R2 constituting the discontinuous phase)
The rubber component R2 is a component listed as a rubber component that can be included in the unvulcanized rubber composition, and can be a discontinuous phase in which E1 / E2 falls within the range of 2 to 10 after vulcanization. There is no particular limitation, and one type may be used or two or more types may be used. For example, it can be selected in consideration of the relationship between the glass transition temperatures Tg1 and Tg2 described above.
However, in the case where two or more kinds of diene polymers (including modified diene polymers; the same applies hereinafter) are used in the rubber component R2, the diene weights in the rubber component R1 that are compatible with each other and constitute a continuous phase. As the coalescence, an incompatible diene polymer is used. When the diene polymer in the rubber component R1 is two or more kinds of diene polymers, any of the diene polymers in the rubber component R2 is any of the diene polymers in the rubber component R1. An incompatible diene polymer is used.
Since the discontinuous phase is required to be a softer phase than the continuous phase, the glass transition temperature Tg2 of the rubber component R2 is preferably −110 to −60 ° C., and is −100 to −65 ° C. Is more preferable, and it is more preferably −100 to −67 ° C.

In the rubber composition of the present invention, the elastic component ratio (E1 / E2) of the rubber composition is easily set to 2 to 10, and from the viewpoint of further improving wet grip performance and low heat generation performance, the rubber component R1 is a modified diene type. It is preferable that the rubber component R2 contains a diene polymer of natural rubber, isoprene rubber or butadiene.

〔resin〕
The rubber component in the present invention may contain a resin.
The resin may be contained in either one of the continuous phase or the discontinuous phase, or may be contained in both, but the rubber composition is made by making the continuous phase harder and the discontinuous phase softer. From the viewpoint of further improving the low heat generation performance and wet grip performance, the resin is preferably localized in the continuous phase.
“The resin is localized in the continuous phase” means that, in the total mass of the resin contained in the rubber composition of the present invention, the amount of the resin contained in the continuous phase is more than the amount of the resin contained in the discontinuous phase. Means many. In the total mass of the resin, the amount of resin contained in the continuous phase (the degree of localization of the resin in the continuous phase) is preferably more than 50% by mass and 100% by mass or less, and more preferably 60% by mass or more.
The degree of localization (partition rate) of the resin in the continuous phase is obtained, for example, by calculating the weight of the resin contained in each phase from the FOX equation using the glass transition temperature (Tg) of the rubber component after addition of the resin. Can be sought.
The content of the resin in the rubber composition of the present invention can be 0 to 30 parts by mass with respect to 100 parts by mass of the total diene polymer in the unvulcanized rubber composition, and 25 parts by mass. The following is preferable.

Examples of the resin include terpene phenol resin, rosin-modified petroleum resin, dicyclopentadiene resin, aliphatic hydrocarbon resin, alicyclic hydrocarbon resin, aromatic hydrocarbon resin, and the like.
The resin is a polymer compound having a glass transition temperature (Tg) of 50 ° C. or higher and a number average molecular weight (Mn) of 5,000 or lower from the viewpoint of further increasing the elastic modulus of the continuous phase of the rubber composition. Is preferred. The resin used may be one type or two or more types.

As rosin-modified petroleum resin, Hyosin S from Taisha Matsuse Oil Co., Ltd .;
Examples of the aromatic hydrocarbon resin C9 resin include Neopolymer L90, Neopolymer 120, Neopolymer E130, Neopolymer 140, Neopolymer 170S, Nippon Oil Neoresin D-145 manufactured by Nippon Petrochemical Co., Ltd .;
Examples of the aliphatic hydrocarbon resin C5 resin include ESCOREZ1102 from Tonex, and Hilets T500X from Mitsui Chemicals;
Examples of the alicyclic hydrocarbon resin include quinton 1500, quinton 1700, quinton 1525L of ZEON Corporation;
Examples of the terpene phenol resin include YS Polystar T80, YS90L, YS Polystar T115, YS Polystar U115, Mighty Ace G125, etc., manufactured by Yashara Chemical Co., Ltd.
Further, as the C5C9 resin, T-REZ R series manufactured by Tonen Chemical Co., Ltd., for example, RD104 can be used.

The method for localizing the resin in the continuous phase is not particularly limited. For example, when preparing an unvulcanized rubber composition, if a resin having an SP value close to the SP value of the rubber component R1 constituting the continuous phase is used. Good. Specifically, a resin in which the difference (| SP1-SP3 |) between the SP value (SP1) of the rubber component R1 and the SP value (SP3) of the resin is less than 0.15 may be selected. The unit of SP value is (cal / cm ³ ) ^0.5 .

[Liquid polymer]
The rubber component in the present invention preferably contains a liquid polymer.
The liquid polymer may be contained in either one of the continuous phase or the discontinuous phase, or may be contained in both, but the rubber composition is made by making the continuous phase harder and the discontinuous phase softer. From the viewpoint of further improving the low heat generation performance and wet grip performance of the product, the liquid polymer is preferably localized in the discontinuous phase.
“The liquid polymer is localized in the discontinuous phase” means that the amount of the liquid polymer contained in the discontinuous phase in the total mass of the liquid polymer contained in the rubber composition of the present invention is the liquid contained in the continuous phase. Means greater than the amount of polymer. In the total mass of the liquid polymer, the amount of the liquid polymer contained in the discontinuous phase (the degree of localization of the liquid polymer in the discontinuous phase) is preferably more than 50% by mass and 100% by mass or less, and more than 60% by mass. More preferred is 70% by mass or more.

The degree of localization (partition rate) of the liquid polymer in the discontinuous phase can be determined, for example, from the shift temperature amount of the glass transition temperature (Tg) measured from DSC for the rubber component. Using the glass transition temperature (Tg) of the rubber component after addition of the liquid polymer, the weight of the liquid polymer contained in each phase is calculated from the FOX equation.

The content of the liquid polymer in the rubber composition of the present invention is more than 0 parts by weight and 50 parts by weight or less with respect to 100 parts by weight of the total diene polymer in the rubber component of the unvulcanized rubber composition. It is preferably 5 to 45 parts by mass.
In addition, from the viewpoint of suppressing excessive softening of the rubber composition, when the rubber composition of the present invention contains a softening agent such as process oil, the rubber composition preferably does not contain a liquid polymer.

The liquid polymer is not particularly limited, and examples thereof include diene liquid polymers such as liquid polyisoprene, liquid polybutadiene, and liquid styrene-butadiene copolymer, liquid polybutene, liquid silicone polymer, and silane liquid polymer.
As the liquid polymer, a commercially available product may be used. For example, Ricon 134 manufactured by Sartomer (Clay Valley) [liquid BR (1,4-polybutadiene structure), number average molecular weight = 8000, vinyl bond content of butadiene portion = 28 mass. %], Ricon 142 (liquid BR (1,4-polybutadiene structure), number average molecular weight = 3900, bound styrene content = 0 mass%, vinyl bond content of butadiene moiety = 55%, polybutadiene liquid at 25 ° C.), Ricon 150 [ Liquid BR (1,4-polybutadiene structure), number average molecular weight = 3900, vinyl bond content of butadiene moiety = 70% by mass], Ricon 154 [liquid BR (1,3-butadiene homopolymer), number average molecular weight = 5200], Ricon 181 [Liquid SBR (Butadiene / Styrene / Ran Mukoporima), number average molecular weight = 3200, vinyl bond content = 30% of the butadiene part, bound styrene content = 28 wt%], and the like.

The liquid polymer has a glass transition temperature (Tg) of −100 to 20 ° C. and a number average molecular weight (Mn) of 1,000 to 50,000 from the viewpoint of softening the discontinuous phase of the rubber composition. It is preferably a molecular compound. The glass transition temperature of the liquid polymer is more preferably from −100 to 0 ° C., and further preferably from −100 to −20 ° C. The number average molecular weight of the liquid polymer is more preferably 3,000 to 30,000, still more preferably 5,000 to 20,000.
The liquid polymer used may be one type or two or more types.

The method for localizing the liquid polymer in the discontinuous phase is not particularly limited. For example, when preparing an unvulcanized rubber composition, a liquid having an SP value close to the SP value of the rubber component R2 constituting the discontinuous phase. A polymer may be used. Specifically, a liquid polymer in which the difference (| SP2-SP4 |) between the SP value (SP2) of the rubber component R2 and the SP value (SP4) of the liquid polymer is less than 0.15 may be selected. The unit of SP value is (cal / cm ³ ) ^0.5 .

〔filler〕
The rubber composition of the first aspect of the present invention preferably contains a filler. The filler may be contained in either one of the continuous phase or the discontinuous phase, or may be contained in both, but the rubber composition is made by making the continuous phase harder and the discontinuous phase softer. From the viewpoint of further improving the low heat generation performance and wet grip performance of the product, the filler is preferably localized in the continuous phase.
On the other hand, the rubber composition of the second present invention contains a filler. From the viewpoint of hardening the continuous phase and softening the discontinuous phase to improve the low heat generation performance and wet grip performance of the rubber composition, the filler is localized in the continuous phase. In the second aspect of the present invention, the filler may be contained only in the continuous phase, or may be further contained in the discontinuous phase.
In the present invention, “the filler is localized in the continuous phase” means that the ratio of the filler contained in the continuous phase among all the fillers (the degree of localization of the filler in the continuous phase) is It means that it is more than the ratio of the diene polymer contained in a continuous phase among diene polymers. This is represented by the following formula.
X _{filler (continuous phase)} = S _{filler (continuous phase)} / [S _{filler (continuous phase)} + S _{filler (non-continuous phase)} ]> M _{diene polymer (continuous phase)} / [M _{diene polymer (continuous phase)} + M _{diene polymer (non-continuous phase)} ]
In the above formula,
X _{filler (continuous phase)} is the degree of localization of the filler to the continuous phase,
S _{filler (continuous phase)} is the filler area contained in the continuous phase (measured from AFM),
S _{filler (discontinuous phase)} is the area of the filler contained in the discontinuous phase (measured from AFM),
M _{diene polymer (continuous phase)} is the mass of the diene polymer contained in the continuous phase,
M _{diene polymer (discontinuous phase)} represents the mass of the diene polymer contained in the discontinuous phase, respectively.
The degree of localization of the filler in the continuous phase is preferably “the ratio of the diene polymer in the continuous phase out of all diene polymers × 1.1 or more”.

The degree of localization (partition rate; mass%) of the filler in the continuous phase is determined by, for example, an atomic force microscope (for example, ASYLUM RESEARCH) in which a smooth surface of a sample cut by a microtome is cooled (for example, 0 ° C.). It can be obtained by measuring with a measurement range of 2 μm × 2 μm using a company MFP-3D).
When measuring a system divided into two components, the region of 2 μm × 2 μm of the rubber composition is observed, and the obtained image is ternary for the two rubber components and the filler portion based on the difference in elastic modulus from the histogram. Then, the filler area contained in the phases of the two rubber components is obtained, and the ratio of the filler present in the continuous phase is calculated from the total amount of filler in the measurement region.
When the filler is on the boundary surface between the two rubber components, two points where the three components of the rubber component and the filler are in contact are connected to divide the area of the filler.

The content of the filler in the rubber composition of the present invention is preferably 50 to 130 parts by mass with respect to 100 parts by mass of the total diene polymer in the rubber component of the unvulcanized rubber composition. 60 to 120 parts by mass is more preferable.

The filler is not particularly limited, and for example, a reinforcing filler that reinforces the rubber composition is used. Examples of the reinforcing filler include silica and carbon black. Either one of silica and carbon black may be used alone, or both silica and carbon black may be used. From the viewpoint of improving wet grip performance, silica is preferably included.
The average aggregate area of the filler is not particularly limited, is preferably 2100 nm ² or less, and more preferably 1800 nm ² or less. Thereby, it is easy to achieve both low heat generation performance and wet grip performance.

The average agglomerate area of the filler is obtained, for example, from FIB-SEM, from the image obtained in the measurement range 4 μm × 4 μm, the agglomerate area of the filler part, and from the total agglomerate surface area of the filler part and the number of agglomerates, The average aggregate area of the filler portion per unit area (2 μm × 2 μm) can be calculated by the number average (arithmetic average). In the calculation, particles in contact with the edge (side) of the image are not counted, and particles of 20 pixels or less are regarded as noise and are not counted.

(silica)
Silica is not particularly limited, and can be used according to applications such as general grade silica, special silica surface-treated with a silane coupling agent, and the like. For example, wet silica is preferably used as the silica.

(Carbon black)
Carbon black is not particularly limited and can be appropriately selected depending on the purpose. The carbon black is preferably, for example, FEF, SRF, HAF, ISAF, or SAF grade, and more preferably HAF, ISAF, or SAF grade.

[Other ingredients]
The rubber component in the present invention can be blended by appropriately selecting compounding agents (excluding fillers) usually used in the rubber industry. Examples of such a compounding agent include an antioxidant, a silane coupling agent, a vulcanization accelerator such as stearic acid, a vulcanization accelerator such as zinc white, and a vulcanizer such as sulfur. A commercial item can be used conveniently for a compounding agent.

<Method for preparing rubber composition for tread>
The method for preparing the rubber composition of the present invention is not particularly limited, and the rubber composition can be obtained by vulcanizing the unvulcanized rubber composition by a known vulcanization method.
Moreover, the preparation method of the unvulcanized rubber composition used as the raw material of the rubber composition of this invention is not specifically limited, The preparation method of a well-known unvulcanized rubber composition can be used.

As a preparation method of the unvulcanized rubber composition, for example,
(A) A method in which the diene polymer in the rubber component R1 constituting the continuous phase and the diene polymer in the rubber component 2 constituting the discontinuous phase are separately kneaded and mixed together;
(B) A method in which the diene polymer in the rubber component R1 constituting the continuous phase and the diene polymer in the rubber component 2 constituting the discontinuous phase are simultaneously mixed and kneaded.

Among the components of the unvulcanized rubber composition, diene polymers such as zinc oxide, anti-aging agent, wax, vulcanization accelerator and sulfur are vulcanized, and the vulcanization of diene polymers is accelerated. The component is referred to as component C. Among the components of the unvulcanized rubber composition, the component excluding component C and diene polymer is referred to as component D.
As a method of (a), more specifically,
(A1) A diene polymer in the rubber component R1 and a component D (D1) necessary for constituting a continuous phase are kneaded to obtain an unvulcanized rubber composition 1, and separately in the rubber component R2. The diene polymer and the component D (D2) necessary for constituting the discontinuous phase are kneaded to obtain an unvulcanized rubber composition 2, each of which is kneaded, and finally the component C is added. Kneading and kneading;
(A2) The diene polymer in the rubber component R1 and the component D (D1) necessary for constituting a continuous phase are kneaded to obtain an unvulcanized rubber composition 1, and then in the rubber component R2. And a method of adding the component D (D1) necessary for constituting the discontinuous phase and kneading, and finally adding the component C and kneading.

More specifically, as the method (b), the diene polymer in the rubber component R1, the diene polymer in the rubber component R2, and the component D (D1 and D2) are kneaded, and then the component C The method of kneading is mentioned.

Examples of the component D1 include a filler, a resin, a liquid polymer, and other components, and preferably include a filler, a resin, and other components. The content of each component may be the amount described as the content in the rubber composition constituting the continuous phase.
Component D2 includes a filler, a resin, a liquid polymer, and other components, and preferably includes a liquid polymer and other components. The content of each component may be the amount described as the content in the rubber composition constituting the discontinuous phase.

Among these, it is preferable to prepare a rubber composition by kneading rubber components and the like by the method (b). By using the method (b), the domain diameter of the discontinuous phase is easily set to 50 to 500 nm. Further, by using the method (b), it becomes difficult to generate a domain having a domain diameter of 5 μm or more.

Each unvulcanized rubber composition is blended into the diene polymer in the rubber component by blending a filler and various compounding agents appropriately selected as necessary, and kneaded, heated, extruded, etc. Can be prepared.

<Tread member, tire>
The tread member of the present invention uses the above-described rubber composition for a tread of the present invention. The tire of the present invention uses the tread member of the present invention.
Thereby, the tread member and the tire are excellent in wet grip performance and low loss performance. Examples of the tread member include, but are not limited to, a tread rubber.
The tire of the present invention is not particularly limited except that the tread rubber composition of the present invention is used for any of the tread members, and can be produced according to a conventional method.

Hereinafter, the present invention will be described in more detail with reference to examples. However, these examples are intended to illustrate the present invention and do not limit the present invention in any way.

The details of the materials used in the examples are as follows.
[Modifier]
Denaturant 1:
N, N-bis (trimethylsilyl) -3- [diethoxy (methyl) silyl] propylamine, equivalent to hydrocarbyloxysilane compound of general formula (IV) 2:
N- (1,3-dimethylbutylidene) -3-triethoxysilyl-1-propanamine, equivalent to the hydrocarbyloxysilane compound of general formula (V)

[Liquid polymer]
Liquid polymer A:
Ricon 134 (liquid BR1 (1,4-polybutadiene structure), manufactured by Sartomer (Clay Valley), number average molecular weight = 8000 (polystyrene equivalent molecular weight = 15100), vinyl bond content of butadiene portion = 28%)
Liquid polymer B:
Ricon 150 [liquid BR2 (1,4-polybutadiene structure), manufactured by Sartomer (Clay Valley), number average molecular weight = 3900 (polystyrene equivalent molecular weight = 7600), vinyl bond content of butadiene portion = 70%]
Liquid polymer C:
Ricon 181 [Liquid SBR (Butadiene / Styrene / Random Copolymer), manufactured by Sartomer (Clay Valley), number average molecular weight = 3200 (polystyrene equivalent molecular weight = 8300), vinyl bond content of butadiene moiety = 30%, bound styrene content = 28 mass%〕

〔resin〕
Resin A: Mitsui Chemicals, Hiretsu T500X (C5 resin)
Resin B: Tonen Chemical Co., Ltd., T-REZ RD104 (C5C9 resin)
Resin C: JX Nippon Oil & Energy Corporation, Nisseki Neopolymer 140 (C9 resin)

〔filler〕
Silica: Trade name “NipSil AQ” manufactured by Tosoh Silica Co., Ltd.
Carbon black: Asahi Carbon Co., Ltd., # 80

[Various ingredients]
Oil (process oil): Idemitsu Kosan Co., Ltd., Diana Process NH-70S
Silane coupling agent: Shin-Etsu Chemical Co., Ltd., ABC-856
Anti-aging agent: Sumitomo Chemical, Antigen 6C
Wax: Seiko Chemical Co., Suntite A
Stearic acid: NOF Corporation, Tungsten zinc stearate Hana: Hakusuitec Co., Ltd., 2 types of zinc oxide Sulfur: Hosoi Chemical Co., Ltd., HK200-5
Vulcanization accelerator: Sumitomo Chemical Co., Ltd., Soxinol DG

(Diene polymer)
The diene polymer used in Examples and Comparative Examples was synthesized by the following method or the following product was used.

(Diene polymer B: modified low Tg-SBR)
To an 800 mL pressure-resistant glass container that has been dried and purged with nitrogen, a cyclohexane solution of 1,3-butadiene and a cyclohexane solution of styrene are added to 67.5 g of 1,3-butadiene and 7.5 g of styrene, and 2,2 After adding 0.6 mmol of -ditetrahydrofurylpropane and 0.8 mmol of n-butyllithium, polymerization was carried out at 50 ° C. for 1.5 hours. At this time, 0.72 mmol of modifier 1 was added as a modifier to the polymerization reaction system having a polymerization conversion rate of almost 100%, and a modification reaction was carried out at 50 ° C. for 30 minutes to obtain a diene polymer B. . The glass transition temperature was measured by differential scanning calorimetry and found to be -62 ° C.

(Diene polymer A: unmodified low Tg-SBR)
In the synthesis of the diene polymer B, the diene system is the same as the polymerization reaction of the diene polymer B except that the polymerization reaction is performed, the modification reaction is not performed, and the termination reaction is performed with isopropyl alcohol (IPA). Polymer A was obtained. As a result of measuring the microstructure of the obtained diene polymer A, the amount of bonded styrene was 10% by mass, the amount of vinyl bond in the butadiene portion was 40%, and the peak molecular weight was 200,000. The glass transition temperature was measured by differential scanning calorimetry and found to be -62 ° C.

(Diene polymer D: modified high Tg-SBR)
Add 1,3-butadiene in cyclohexane and styrene in cyclohexane to a dry, nitrogen-substituted 800 mL pressure-resistant glass container so that 45 g of 1,3-butadiene and 30 g of styrene are added, and 2,2-ditetrahydrofuryl is added. After adding 0.16 mmol of propane and 0.8 mmol of n-butyllithium, polymerization was carried out at 50 ° C. for 1.5 hours. At this time, 0.72 mmol of modifier 2 was added as a modifier to the polymerization reaction system in which the polymerization conversion rate was almost 100%, and a modification reaction was performed at 50 ° C. for 30 minutes to obtain a diene polymer D. . The glass transition temperature was measured by differential scanning calorimetry and found to be -32 ° C.

Diene polymer C: manufactured by JSR Corporation, JSR 0202 (unmodified high Tg-SBR, Tg = −23 ° C.)
Diene polymer E: UBE 150, manufactured by Ube Industries, Ltd. (BR, Tg = −95 ° C.)
Diene polymer F: TSR20 (NR, Tg = −70 ° C.)

<Examples 1-1 to 1-16, 1-18, and Comparative Examples 1-1 to 1-4>
[Manufacture of rubber composition for tread]
Among the components shown in Tables 1 to 3, components other than zinc oxide (zinc white), anti-aging agent, wax, vulcanization accelerator, and sulfur are started using a Banbury mixer based on the formulations shown in Tables 1 to 3. The mixture was kneaded for 5 minutes at a temperature of 100 C and a rotation speed of 70 rpm. Thereafter, zinc oxide, anti-aging agent, wax, vulcanization accelerator, and sulfur were kneaded in the final kneading step based on the formulations shown in Tables 1 to 3 to prepare an unvulcanized rubber composition.
Each obtained unvulcanized rubber composition was vulcanized at 160 C for 20 minutes to produce a tread rubber composition.

<Example 1-17>
The diene polymer D, stearic acid, filler (silica), and silane coupling agent of the formulation shown in Table 3 were kneaded for 3 minutes at a starting temperature of 100 ° C. and a rotational speed of 70 rpm using a Banbury mixer (master). Batch kneading process). After the masterbatch kneading process, the diene polymer E and the liquid polymer are mixed and kneaded for 5 minutes, and the final kneading process of zinc oxide (zinc white), anti-aging agent, wax, vulcanization accelerator, and sulfur. To prepare an unvulcanized rubber composition of Example 1-17.
The obtained unvulcanized rubber composition was vulcanized at 160 C for 20 minutes to produce a tread rubber composition of Example 1-17.

<Examples 2-1 to 2-19, Comparative Examples 2-1 to 2-3>
[Manufacture of rubber composition for tread]
Among the components shown in Tables 4 to 6, components other than zinc oxide (zinc white), anti-aging agent, wax, vulcanization accelerator, and sulfur were started using a Banbury mixer based on the formulations shown in Tables 4 to 6. The mixture was kneaded for 5 minutes at a temperature of 100 C and a rotation speed of 70 rpm. Thereafter, zinc oxide, anti-aging agent, wax, vulcanization accelerator, and sulfur were kneaded in the final kneading step based on the formulations shown in Tables 4 to 6 to prepare an unvulcanized rubber composition.
Each obtained unvulcanized rubber composition was vulcanized at 160 C for 20 minutes to produce a tread rubber composition.

With respect to each manufactured rubber composition, the following measurements (1) to (8) were performed.
(1) Elastic modulus of rubber composition constituting continuous phase (E) E1
(2) Elastic modulus (E) E2 of rubber composition constituting discontinuous phase
(3) Tg of rubber component constituting continuous phase (Tg1)
(4) Tg of rubber component constituting discontinuous phase (Tg2)
(5) Localization degree of the filler to the continuous phase (6) Localization degree of the liquid polymer to the discontinuous phase (7) Localization degree to the continuous phase of the resin (8) Confirmation of presence / absence of domains of 5 μm or more

Measurements (1) to (8) were performed by the method described above. Also, E1 / E2 was calculated based on the results of (1) and (2), and the Tg difference (Tg1−Tg2) (° C.) of the rubber component of each phase was calculated based on the results of (3) and (4). . Each rubber composition was evaluated for wet grip performance and low loss performance (low heat generation performance).

1. Evaluation of wet grip performance The resistance value was measured by rubbing the wet concrete road surface with a test piece of each rubber composition at room temperature using a British portable skid tester (BPST).
In Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-3 in Table 1, the comparative example 1-1 was set as 100 and indicated as an index. Further, in Examples 1-4 to 1-18 and Comparative Example 1-4 in Tables 2 and 3, the index was displayed with Comparative Example 1-4 as 100.
In Tables 4 to 6, the comparative example 2-1 was set as 100 and indicated as an index.
The results are shown in Tables 1-6.
The larger the index value, the larger the resistance value, indicating better wet grip performance.

2. Evaluation of Low Loss Performance (Low Heat Generation Performance) For each rubber composition, loss tangent (tan δ) was measured using a viscoelasticity measuring device (manufactured by Rheometrics) at a temperature of 50 ° C., a strain of 5%, and a frequency of 15 Hz. It was measured.
The obtained tan δ values are expressed as indices in the reciprocals of Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-3 in Table 1 with the value of Comparative Example 1-1 being 100. did. Further, in Examples 1-4 to 1-18 and Comparative Example 1-4 in Tables 2 and 3, the index was displayed with Comparative Example 1-4 as 100.
In Tables 4 to 6, the comparative example 2-1 was set as 100 and indicated as an index.
The results are shown in Tables 1-6.
The larger the index value, the better the low loss performance.

3. Total index The total (total index) of the index calculated in “1. Evaluation of wet grip performance” and the index calculated in “2. Evaluation of low loss performance (low heat generation performance)” is shown in Tables 1-6. . The larger the index value, the better the balance between wet grip performance and low loss performance (low heat generation performance).

As shown in Tables 1 to 3, the elastic modulus E1 at 0 ° C. of the rubber composition constituting the continuous phase and the elastic modulus E2 at 0 ° C. of the rubber composition constituting the discontinuous phase are 2 ≦ (E1 / E2) A rubber composition for tread satisfying ≦ 10 was found to be excellent in wet grip performance without impairing low heat generation performance. Therefore, a tread member and a tire using such a tread rubber composition are considered to be excellent in wet grip performance without impairing low loss performance.

Further, as shown in Tables 4 to 6, the filler is localized in the continuous phase (“the degree of localization of the filler in the continuous phase” exceeds 70%), and the rubber component glass constituting the continuous phase The transition temperature Tg1 and the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase are Tg1> Tg2, that is, “Tg difference between the rubber components of each phase (Tg1−Tg2) (° C.)” is a positive value. The tread rubber composition was found to be excellent in both wet grip performance and low heat generation performance. Therefore, it is considered that a tread member and a tire using such a tread rubber composition are excellent in wet grip performance and low loss performance.

According to the present invention, it is possible to provide a rubber composition for a tread which is excellent in wet grip performance without impairing low heat generation performance. Moreover, according to this invention, the tread member and tire which are excellent in wet grip performance can be provided, without impairing low-loss performance.

2 Continuous phase 4 Non-continuous phase 6 Filler

Claims (17)

1. A rubber composition for a tread obtained by vulcanizing an unvulcanized rubber composition containing a rubber component containing a diene polymer, having a continuous phase and one or more discontinuous phases,
   Tread in which the elastic modulus E1 at 0 ° C. of the rubber composition constituting the continuous phase and the elastic modulus E2 at 0 ° C. of the rubber composition constituting the discontinuous phase satisfy 2 ≦ (E1 / E2) ≦ 10 Rubber composition.
2. The rubber composition for a tread according to claim 1, wherein the glass transition temperature Tg1 of the rubber component constituting the continuous phase and the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase satisfy Tg1> Tg2.
3. The rubber for tread according to claim 1 or 2, wherein the glass transition temperature Tg1 of the rubber component constituting the continuous phase and the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase satisfy Tg1-Tg2 ≧ 20 ° C. Composition.
4. The rubber composition for a tread according to any one of claims 1 to 3, further comprising a filler, wherein the filler is localized in the continuous phase.
5. The rubber composition for a tread according to any one of claims 1 to 4, further comprising a liquid polymer, wherein the liquid polymer is localized in the discontinuous phase.
6. The rubber composition for a tread according to any one of claims 1 to 5, comprising a resin, and the resin is localized in the continuous phase.
7. A rubber composition for a tread obtained by vulcanizing an unvulcanized rubber composition containing a rubber component containing a diene polymer, having a continuous phase and one or more discontinuous phases,
   Including a filler, wherein the filler is localized in the continuous phase;
   A rubber composition for a tread in which the glass transition temperature Tg1 of the rubber component constituting the continuous phase and the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase satisfy Tg1> Tg2.
8. The rubber composition for a tread according to claim 7, wherein the glass transition temperature Tg1 of the rubber component constituting the continuous phase and the glass transition temperature Tg2 of the rubber component constituting the discontinuous phase satisfy Tg1-Tg2 ≧ 20 ° C. .
9. The rubber composition for a tread according to claim 7 or 8, comprising a liquid polymer, wherein the liquid polymer is localized in the discontinuous phase.
10. The rubber composition for a tread according to any one of claims 7 to 9, comprising a resin and the resin is localized in the continuous phase.
11. The elastic modulus E1 at 0 ° C. of the rubber composition constituting the continuous phase and the elastic modulus E2 at 0 ° C. of the rubber composition constituting the discontinuous phase satisfy 2 ≦ (E1 / E2) ≦ 10. Item 11. The rubber composition for a tread according to any one of Items 7 to 10.
12. The rubber composition for a tread according to any one of claims 1 to 11, wherein the domain diameter of the discontinuous phase is 50 to 500 nm.
13. The ratio of the filler contained in the continuous phase among all the fillers is larger than the ratio of the diene polymer contained in the continuous phase among all the diene polymers. Rubber composition for treads.
14. The tread according to any one of claims 5, 6, and 9 to 13, wherein the amount of the liquid polymer contained in the discontinuous phase is more than 50% by mass and 100% by mass or less in the total mass of the liquid polymer. Rubber composition.
15. The rubber composition for a tread according to any one of claims 6 and 10 to 14, wherein, in the total mass of the resin, the amount of the resin contained in the continuous phase is more than 50 mass% and 100 mass% or less.
16. A tread member using the rubber composition for a tread according to any one of claims 1 to 15.
17. A tire using the tread member according to claim 16.

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