JP2020094113A - Rubber composition and tire - Google Patents

Abstract

To provide a rubber composition capable of highly achieving all of snow performance, wet performance, low rolling resistance, and steering stability, and to provide a tire using the same.SOLUTION: There is provided a rubber composition including: a rubber component (A); a filler (B); a thermoplastic resin (C) containing at least one kind selected from a group consisting of a styrene alkylene block copolymer and a polyester polyol resin having an aromatic ring; and a polymer material (D) having no diene skeleton in the molecular skeleton. In the rubber component (A), at least one kind selected from the group consisting of natural rubber, butadiene rubber and synthetic isoprene rubber are contained in total of 10 mass% or more and a modified conjugated diene polymer is contained in an amount of 5 mass% or more. The polymer material (D) has a weight average molecular weight of 1000 to 50000. The rubber composition contains the thermoplastic resin (C) and the polymer material (D) of 0.5 to 40 pts.mass, respectively, based on 100 pts.mass of the rubber component (A).SELECTED DRAWING: None

Description

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

Tires have been developed and used in a wide variety of ways depending on the application. Among them, the types of tires are classified into summer tires, all-season tires and winter tires according to the time of use. Among them, winter tires and summer tires have been conventionally used properly. On the other hand, all-season tires have recently been required to exhibit various performances in a wide temperature range, and in particular, a rubber composition for a tire in which SNOW performance, WET performance, and low rolling resistance coexist. The thing is examined (for example, patent document 1).

JP-A-2017-075253

However, the technique of Patent Document 1 does not exhibit the effect of low rolling resistance, and provides a rubber composition capable of obtaining a tire excellent in SNOW performance, WET performance, and low rolling resistance. The challenges are not compatible. Furthermore, the technique of Patent Document 1 does not consider steering stability, which is one of the most important indicators in running performance.

Therefore, the present invention provides a rubber composition capable of highly paralleling SNOW performance, WET performance, low rolling resistance and steering stability, and SNOW performance, WET performance, low rolling resistance when used for a tire. It is an object of the present invention to provide a tire in which the stability and steering stability are highly parallel.

The gist of the present invention which solves the above problems is as follows.

The rubber composition according to the present invention comprises a rubber component (A), a filler (B), at least one selected from the group consisting of a styrene/alkylene block copolymer and a polyester polyol resin having an aromatic ring. Containing a thermoplastic resin (C) and a polymer material (D) having no diene skeleton in the molecular skeleton,
In the rubber component (A), at least one selected from the group consisting of natural rubber, butadiene rubber and synthetic isoprene rubber is contained in a total amount of 10% by mass or more, and a modified conjugated diene polymer is contained in an amount of 5% by mass or more. Then
The polymer material (D) has a weight average molecular weight of 1,000 to 50,000,
The thermoplastic resin (C) and the polymer material (D) are each contained in an amount of 0.5 to 40 parts by mass with respect to 100 parts by mass of the rubber component (A).
By applying such a rubber composition according to the present invention to a tire, SNOW performance, WET performance, low rolling resistance and steering stability (steering stability on a dry road surface) can be highly parallelized.

In the rubber composition according to the present invention, the polymer material (D) is preferably at least one selected from the group consisting of polybutene and acrylic resin.
Thereby, the WET performance can be improved.

In the rubber composition according to the present invention, the polybutene is preferably an unmodified homopolymer.
This further improves the WET performance.

In the rubber composition according to the present invention, alkylene blocks of the styrene-alkylene block _{copolymers, - (CH 2 -CH (C} 2 H 5)) - units _{(C A)} and _- (CH 2 _-CH 2) - and a unit _{(C B),} that the total content of the units _{(C a)} is, based on the total weight of the unit _{(C a)} and the unit _{(C B),} is 40 mass% or more Is preferred.
As a result, steering stability is further improved.

In the rubber composition according to the present invention, alkylene blocks of the styrene-alkylene block _{copolymers, - (CH 2 -CH (C} 2 H 5)) - units _{(C A)} and _- (CH 2 _-CH 2) - and a unit _{(C B),} the total content of the units _{(C a)} is, based on the total weight of the unit _{(C a)} and the unit _{(C B),} is 60 mass% or more, Moreover, the total styrene content in the styrene/alkylene block copolymer is preferably 30% by mass or more.
As a result, steering stability is further improved.

In the rubber composition according to the present invention, the filler (B) preferably contains at least silica.
Thereby, the low rolling resistance is further improved.

In the rubber composition according to the present invention, it is preferable that the filler (B) further contains carbon black, and the proportion of the silica in the total mass of the filler (B) is 75% by mass or more.
Thereby, the low rolling resistance is further improved.

The rubber composition according to the present invention preferably further contains 1 part by mass or more of the softening agent (E) with respect to 100 parts by mass of the rubber component (A).
This further improves the SNOW performance.

The rubber composition according to the present invention preferably further contains 5 to 40 parts by mass of the inorganic particles (F) with respect to 100 parts by mass of the rubber component (A).
This further improves the WET performance.

A tire according to the present invention is characterized by using the above rubber composition.
The tires of the present invention are highly parallel to each other in SNOW performance, WET performance, low rolling resistance and steering stability.

According to the present invention, it is possible to provide a rubber composition capable of highly paralleling SNOW performance, WET performance, low rolling resistance and steering stability when used in a tire.
Another object of the present invention is to provide a tire in which SNOW performance, WET performance, low rolling resistance, and steering stability are highly parallel.
According to the present invention, it is possible to provide a tire in which SNOW performance, WET performance, low rolling resistance, and steering stability are highly parallel.

Hereinafter, embodiments of the present invention will be described. These descriptions are for the purpose of illustrating the present invention and are not intended to limit the present invention in any way.

"Rubber composition"
The rubber composition according to the present invention comprises a rubber component (A), a filler (B), at least one selected from the group consisting of a styrene/alkylene block copolymer and a polyester polyol resin having an aromatic ring. Containing a thermoplastic resin (C) and a polymer material (D) having no diene skeleton in the molecular skeleton,
In the rubber component (A), at least one selected from the group consisting of natural rubber, butadiene rubber and synthetic isoprene rubber is contained in a total amount of 10% by mass or more, and a modified conjugated diene polymer is contained in an amount of 5% by mass or more. Then
The polymer material (D) has a weight average molecular weight of 1,000 to 50,000,
The thermoplastic resin (C) and the polymer material (D) are each contained in an amount of 0.5 to 40 parts by mass with respect to 100 parts by mass of the rubber component (A).

With a rubber composition comprising a rubber component (A) containing a modified conjugated diene polymer, a specific thermoplastic resin (C), and a polymer material (D) having no diene skeleton in the molecular skeleton, It is possible to provide a rubber composition used for a tire which is excellent in SNOW performance, WET performance, low rolling resistance and steering stability. By applying the polymer material (D) having no diene skeleton in the molecular skeleton to the rubber composition used for the tire, it is possible to improve the WET performance without increasing the elastic modulus in the low temperature range. Is. Then, for this system, by combining a rubber component (A) containing a modified conjugated diene-based polymer having a low rolling resistance effect and a specific thermoplastic resin (C) having an elastic modulus improving effect, It is considered that the above four problems can be solved.

<Rubber component (A)>
The rubber composition according to the present invention comprises at least one selected from the group consisting of natural rubber (NR), butadiene rubber (BR) and synthetic isoprene rubber (IR), and a modified conjugated diene polymer as a rubber component ( Included as A). As a result, the low rolling resistance effect in the low temperature region can be improved.

As the modified conjugated diene polymer, modified styrene-butadiene rubber (SBR) is preferable. As the modified styrene-butadiene rubber, the modified (co)polymer as the polymer component P2 of WO 2017/0777712 and the modified polymer C, the modified polymer D, and the international publication 2018/186367 described in the examples. And the modified conjugated diene-based polymer (A2) described in No.

The rubber composition according to the present invention comprises a natural rubber (NR), a butadiene rubber (BR) and a synthetic isoprene rubber (IR) in the rubber component (A), that is, based on the total mass of the rubber component (A). It contains at least one kind selected from the group consisting of 10 mass% or more in total. When the total content of at least one selected from the group consisting of the natural rubber (NR), the butadiene rubber (BR), and the synthetic isoprene rubber (IR) is 10% by mass or more, the low temperature range is low. Rolling resistance is improved. Further, the rubber composition according to the present invention preferably contains natural rubber (NR), butadiene rubber (BR) and synthetic isoprene rubber (IR) in an amount of 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or more. Contains less than or equal to mass %.

The rubber composition according to the present invention contains 5% by mass or more of the modified conjugated diene-based polymer in the rubber component (A), that is, based on the total mass of the rubber component (A). The compounding amount of the modified conjugated diene polymer in the rubber component (A) is preferably 25 to 40% by mass, more preferably 30 to 35% by mass. When the content of the modified conjugated diene polymer (A1) in the rubber component is 5% by mass or more, when applied to a tire, the WET performance of the tire can be further improved. Further, when the content of the modified conjugated diene polymer in the rubber component is 40% by mass or less, the processability of the rubber composition is improved.

In the rubber composition according to the present invention, when natural rubber is included as the rubber component (A), the ratio of the natural rubber in the rubber component is preferably 20% by mass or more, and 30% by mass or more and 70% by mass. % Or less is more preferable. When the blending amount of natural rubber is within the above range, cold resistance and low rolling resistance can be further improved.

When the butadiene rubber is contained as the rubber component (A) in the rubber composition according to the present invention, the proportion of the butadiene rubber in the rubber component is preferably 20% by mass or more, and 30% by mass or more and 70% by mass. % Or less is more preferable. When the compounding amount of the butadiene rubber is within the above range, cold resistance and low rolling resistance can be further improved.

In the rubber composition according to the present invention, when a synthetic isoprene rubber is included as the rubber component (A), the proportion of the synthetic isoprene rubber in the rubber component is preferably 20% by mass or more, and 30% by mass or more. It is more preferably 70% by mass or less. When the compounding amount of the synthetic isoprene rubber is within the above range, cold resistance and low rolling resistance can be further improved.

Regarding the constitution of the rubber component (A), for example, from the viewpoint that excellent strength, excellent low rolling performance or excellent steering stability can be obtained, the natural rubber (NR), butadiene rubber (BR) and Other than the synthetic isoprene rubber (IR), other diene rubbers or rubbers other than the diene rubbers (hereinafter, may be referred to as “non-diene rubbers”) may be further contained.

Here, the other diene rubber is not particularly limited, and a known diene rubber can be used. Examples of the diene rubber include styrene/butadiene rubber (SBR), styrene/isoprene/butadiene rubber (SIBR), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR) and modified products thereof. As the rubber component, one type may be used alone, or two or more types may be used in combination.

The rubber component may be composed of 100% of the diene rubber, but may contain a non-diene rubber as long as the object of the present invention is not impaired.

Examples of the non-diene rubbers include ethylene/propylene/diene rubber (EPDM), ethylene/propylene rubber (EPM), and butyl rubber (IIR).

These rubbers may be used alone or as a blend of two or more.

<Filler (B)>
The rubber composition according to the present invention contains a filler (B). Examples of the filler (B) include silica, carbon black, aluminum oxide, clay, alumina, talc, mica, kaolin, glass balloons, glass beads, calcium carbonate, magnesium carbonate, magnesium hydroxide, calcium carbonate, magnesium oxide. , Titanium oxide, potassium titanate, barium sulfate, and the like. The fillers may be used alone or in combination of two or more. From the viewpoint of reinforcing properties and low rolling resistance, the filler preferably contains silica.

The silica is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, and aluminum silicate.

BET specific surface area of silica is not particularly limited, for example, a 40~350m ² / g, or 80~300m ² / g, preferably from 150~280m ² / g, more preferably 200~250m ² / g.

The average primary particle diameter of silica is more preferably 5 to 45 nm. In the present specification, the average particle diameter of silica is measured by a method of randomly selecting 100 fine particles with an electron microscope, measuring the major axis of each, and arithmetically averaging the measured 100 major axes.

The amount of silica in the filler (B) is not particularly limited and can be appropriately adjusted according to the purpose, but is preferably 75% by mass or more, and 75% by mass or more 100 with respect to the total mass of the filler. It is more preferably not more than 100% by mass, particularly preferably not less than 90% by mass and not more than 100% by mass.

The carbon black is not particularly limited, and examples thereof include high, medium or low structure carbon black such as SAF, ISAF, ISAF-HS, IISAF, N339, HAF, FEF, GPF and SRF grade.

The blending amount of carbon black is not particularly limited, but is, for example, 5 parts by mass or more and 50 parts by mass or less, and more preferably 5 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the rubber component. When carbon black and silica are used in combination, the total blending amount of carbon black and silica is preferably 25 parts by mass or more and 130 parts by mass or less, more preferably 100 parts by mass of the rubber component. It is 50 parts by mass or more and 90 parts by mass or less.

The compounding amount of the filler is not particularly limited and may be appropriately adjusted. For example, it is 20 parts by mass or more and 120 parts by mass or less with respect to 100 parts by mass of the rubber component. From the viewpoint of low rolling resistance and WET performance, the blending amount of the filler is preferably 50 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the rubber component.

The preferred form of the filler (B) in the present invention contains at least silica and carbon black from the viewpoint of low rolling resistance, and the mass ratio of silica is 75% in the total mass of the filler (B). That is all.

<Thermoplastic resin (C)>
The rubber composition according to the present invention contains a thermoplastic resin (C). The thermoplastic resin (C) contains at least one of a styrene/alkylene block copolymer and a polyester polyol resin having an aromatic ring. In the rubber composition according to the present invention, as the thermoplastic resin (C), one type may be used alone, or two or more types may be used in combination. By blending the thermoplastic resin (C) in the present invention with the rubber composition, the elastic modulus is improved, and thus the steering stability can be improved.

The total compounding amount of the thermoplastic resin (C) is 0.5 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the rubber component. When the blending amount of the thermoplastic resin (C) is within the above range, the elastic modulus is improved, and thus the steering stability can be improved. The blending amount of the thermoplastic resin (C) is preferably, for example, 3 parts by mass or more, 7 parts by mass or more, and 13 parts by mass or more with respect to 100 parts by mass of the rubber component. Further, the blending amount of the thermoplastic resin (C) is preferably, for example, 37 parts by mass or less, 29 parts by mass or less, and 22 parts by mass or less with respect to 100 parts by mass of the rubber component.

(Styrene/alkylene block copolymer)
The styrene/alkylene block copolymer is a copolymer having a block derived from a styrene-based monomer (hereinafter also referred to as a styrene block) and an alkylene block. The styrene/alkylene block copolymer may be used alone or in combination of two or more. By blending the styrene/alkylene block copolymer with the rubber composition, the elastic modulus is improved, and thus the steering stability can be improved.

The total styrene content (total content of blocks derived from styrene-based monomers) of the styrene/alkylene block copolymer is preferably 30% by mass or more, and more preferably 30% by mass or more and 60% by mass or less. .. When the total styrene content is 30% by mass or more, the rigidity of the tire composition is improved, and the steering stability is further enhanced. On the other hand, when the total styrene content is 60% by mass or less, the flexibility of the tire can be secured to some extent, so that the WET performance is further improved.

In the rubber composition according to the present invention, the total styrene content is more preferably 40% by mass or more, or 50% by mass or more. Thereby, steering stability can be further enhanced.

In the present invention, the styrene content of the styrene/alkylene block copolymer and the content of alkylene units described later are determined by the ¹ H-NMR integral ratio.

The styrene block of the styrene/alkylene block copolymer has a unit derived from a styrene monomer (polymerized styrene monomer). Examples of such a styrene-based monomer include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene and the like. Among these, styrene is preferable as the styrene-based monomer.

The alkylene block of the styrene/alkylene block copolymer has an alkylene (divalent saturated hydrocarbon group) unit. Examples of such an alkylene unit include an alkylene group having 1 to 20 carbon atoms. The alkylene unit may have a linear structure, a branched structure, or a combination thereof. The alkylene units of the linear structure, for _{example, - (CH 2 -CH 2)} - units (ethylene _{units), - (CH 2 -CH 2} -CH 2) - units (propylene units), - _(CH 2 -CH ₂ -CH ₂ -CH ₂₎ - units (butylene units), and the like. The alkylene units of the branched structure, for _{example, - (CH 2 -CH (CH} 3)) - units (propylene _{units), - (CH 2 -CH (} C 2 H 5)) - is like a unit (butylene units) Be done. Among these, alkylene _{units, - (CH 2 -CH (C} 2 H 5)) - units, and / or - _{(CH 2} -CH 2) - preferably has a unit.

The total content of alkylene units depends on the type of alkylene used, but is, for example, 40% by mass or more and 70% by mass or less based on the total mass of the styrene/alkylene block copolymer.

The rubber composition according to the present invention, alkylene blocks of the styrene-alkylene block _{copolymer, - (CH 2 -CH (C} 2 H 5)) - units _(C A) and (butylene units) - (CH ₂ -CH ₂₎ - and a unit _(C B) (ethylene units), the total content of the units _{(C a)} is, based on the total weight of the unit _{(C a)} and the unit _{(C B)} , 40 mass% or more is preferable. The total content of the units (C _A) is In the above-mentioned range, steering stability is further improved. From the viewpoint of ensuring good steering stability, the total content of the units (C _A ) is more preferably 50% by mass or more and 90% by mass or less. The lower limit of the total content of the unit (C _A) is more preferably 60 mass% or more, even more preferably in 65 mass% or more, the upper limit of the total content of the unit (C _A) is more preferably 85 It is not more than 80% by mass, more preferably not more than 80% by mass. Incidentally, the unit (C _A) (butylene units) is not less than 50 wt%, butylenes units without taking a crystal structure, it is possible to take a more flexible structure, WET performance or steering stability is further improved ..

In the rubber composition according to the present invention, the styrene/alkylene block copolymer includes styrene/ethylene butylene/styrene block copolymer (SEBS), styrene/ethylene propylene/styrene block copolymer (SEPS) and styrene/ethylene. It is preferably at least one selected from the group consisting of ethylene propylene/styrene block copolymer (SEEPS). The above-exemplified polymers further improve steering stability.

In the rubber composition according to the present invention, the styrene/alkylene block copolymer is preferably a styrene/ethylenebutylene/styrene block copolymer. As a result, steering stability can be secured. The ethylene butylene block of the styrene/ethylene butylene/styrene block copolymer is a block having the above-mentioned ethylene unit and butylene unit.

The styrene/alkylene block copolymer may contain a constitutional unit other than the styrene block and the alkylene block. Examples of such other structural units, for _{example, - (CH 2 -CH (CH} = CH 2)) - , a structural unit having an unsaturated bond such as a unit and the like.

The method for preparing the styrene/alkylene block copolymer is not particularly limited, and a known method can be used. For example, a styrene monomer such as styrene and a conjugated diene compound such as 1,3-butadiene or an olefin such as butene are copolymerized to obtain a precursor copolymer, and the precursor copolymer is hydrogenated. Thus, a styrene/alkylene block copolymer can be obtained.

A commercially available product may be used as the styrene/alkylene block copolymer. Examples of such commercially available products include "DYNARON (registered trademark) 8903P" manufactured by JSR and "DYNARON (registered trademark) 9901P" manufactured by JSR.

When the styrene/alkylene block copolymer is contained as the thermoplastic resin (C), the compounding amount of the styrene/alkylene block copolymer is 0.5 parts by mass or more and 40 parts by mass or more with respect to 100 parts by mass of the rubber component. Below the section. When the blending amount is within the above range, the elastic modulus is improved, so that the steering stability can be improved. The compounding amount of the styrene/alkylene block copolymer is preferably, for example, 3 parts by mass or more, 7 parts by mass or more, and 13 parts by mass or more with respect to 100 parts by mass of the rubber component. Further, the blending amount of the styrene/alkylene block copolymer is preferably, for example, 37 parts by mass or less, 29 parts by mass or less, 22 parts by mass or less, and 17 parts by mass or less with respect to 100 parts by mass of the rubber component.
As the thermoplastic resin (C), if it contains styrene-alkylene block copolymers, alkylene blocks of the styrene-alkylene block _{copolymers, - (CH 2 -CH (C} 2 H 5)) - units (C _a) a - _{(CH 2} -CH 2) - and a unit _{(C B),} the total content of the units _{(C a)} is the total mass of the unit _{(C a)} and the unit _{(C B)} On the other hand, it is preferably 60% by mass or more and the total styrene content in the styrene/alkylene block copolymer is 30% by mass or more.

(Polyester polyol resin having an aromatic ring)
The polyester polyol resin having an aromatic ring in the present invention is not particularly limited and can be appropriately selected according to the purpose. The polyester polyol resin having an aromatic ring is, for example, a polycondensation product of an aromatic polyvalent carboxylic acid and a polyhydric alcohol, which is a resin having two or more hydroxyl groups in one molecule, or a polyvalent carboxylic acid. And a polycondensate of an aromatic polyhydric alcohol, which includes a resin having two or more hydroxyl groups in one molecule. The polyester polyol resin having an aromatic ring may be used alone or in combination of two or more.

By blending the polyester polyol resin having an aromatic ring with the rubber composition, the elastic modulus is improved, and thus the steering stability is further improved.

Examples of the aromatic polycarboxylic acid include isophthalic acid, phthalic acid and terephthalic acid.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, 1,6-hexanediol, methylpentanediol, propylene glycol, dipropylene glycol, 1,4-butanediol, trimethylolethane, trimethylolpropane and neo. Examples include pentyl glycol and the like.

Examples of the polyvalent carboxylic acid include sebacic acid, adipic acid and azelaic acid.

Examples of the aromatic polyhydric alcohol include catechol, bisphenol A, resorcinol and the like.

The polyester polyol resin having an aromatic ring in the present invention preferably has a hydroxyl value of 45 to 78 mgKOH/g. The number of hydroxyl groups in one molecule in the polyester polyol resin is preferably 3 or more, more preferably 4 or more, still more preferably 5 or more. The weight average molecular weight of the polyester polyol resin having the aromatic ring is preferably 25,000 to 70,000.

When a polyester polyol resin having an aromatic ring is contained as the thermoplastic resin (C), the blending amount of the polyester polyol resin having an aromatic ring is 0.5 parts by mass or more based on 100 parts by mass of the rubber component. It is 40 parts by mass or less. When the blending amount is in the above range, the elastic modulus is improved, and the steering stability is further improved. The blending amount of the polyester polyol resin is preferably, for example, 3 parts by mass or more, 7 parts by mass or more, and 13 parts by mass or more with respect to 100 parts by mass of the rubber component. Further, the blending amount of the polyester polyol resin is preferably, for example, 37 parts by mass or less, 29 parts by mass or less, 22 parts by mass or less, and 17 parts by mass or less with respect to 100 parts by mass of the rubber component.

(Other thermoplastic resins)
The thermoplastic resin (C) in the present invention requires another thermoplastic resin (C1) in addition to at least one of the above-mentioned styrene/alkylene block copolymer and polyester polyol resin having an aromatic ring. May be further included by The type of the thermoplastic resin (C1) is not particularly limited, and examples thereof include C5 resin, C9 resin, C5-C9 resin, dicyclopentadiene resin, rosin resin, alkylphenol resin, or terpene. Examples include phenolic resins. These may or may not be hydrogenated. When the thermoplastic resin further contains another thermoplastic resin (C1), the compatibility of the rubber component with the styrene/alkylene block copolymer, the polyester polyol resin having an aromatic ring, or the like is improved, so that the rubber composition can be easily processed. Become.

When (C) is included as the thermoplastic resin and the other thermoplastic resin (C1) is included, the blending amount of the other thermoplastic resin (C1) is not particularly limited, but may be 100 parts by mass of the rubber component. On the other hand, it is preferably 5 parts by mass or more and 50 parts by mass or less. When the blending amount of the other thermoplastic resin (C1) is 5 parts by mass or more and 50 parts by mass or less, braking performance when the rubber composition is used for a tire is further improved.

<Polymer material having no diene skeleton in the molecular skeleton (D)>
The rubber composition according to the present invention contains a polymer material (D) having no diene skeleton in the molecular skeleton. By blending the polymer material (D) in the rubber composition, the WET performance can be improved without increasing the elastic modulus in the low temperature region. The polymer material is preferably liquid at room temperature (20°C to 30°C).

In the present specification, the “polymer material having no diene skeleton in the molecular skeleton” means a polymer material having no repeating unit having two or more unsaturated bonds in the molecule of the polymer material. For example, it refers to a material obtained by hydrogenating unsaturated bonds in the obtained polymer to be saturated. Specific examples thereof include polyolefin resins such as polyethylene (PE), polypropylene (PP) and polybutene (PB), or acrylic resins.

The weight average molecular weight of the polymer material (D) is 1,000 to 50,000. When the weight average molecular weight is in the above range, the WET performance can be improved without increasing the elastic modulus in the low temperature region. A more preferable weight average molecular weight range is 1,000 to 20,000.

When the effect of exerting the WET performance over a long period of time is emphasized, the weight average molecular weight of the polymer material (D) is preferably 6000 to 15000. On the other hand, when importance is attached to the high-speed and immediate effect of the WET performance, the weight average molecular weight of the polymer material (D) is preferably 1500 to 4500.

The weight average molecular weight of the present specification is measured by GPC (gel permeation chromatography). Moreover, the said weight average molecular weight is a standard polystyrene conversion molecular weight.

The polymer material (D) having no diene skeleton in the molecular skeleton improves the WET performance without increasing the elastic modulus in the low temperature region. Therefore, by further combining the modified conjugated diene polymer and the thermoplastic resin (C), a rubber composition in which SNOW performance, low rolling resistance and handling stability are highly parallelized while maintaining high WET performance. It is thought that it can be provided.

In the rubber composition according to the present invention, the total compounding amount of the polymer material (D) having no diene skeleton in the molecular skeleton is 0.5 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the rubber component. Is. When the blending amount of the polymer material (D) is within the above range, the WET performance can be improved. The total amount of the polymer material (D) having no diene skeleton in the molecular skeleton is, for example, 3 parts by mass or more, 7 parts by mass or more, and 13 parts by mass or more with respect to 100 parts by mass of the rubber component. Preferably. The total amount of the polymer material (D) is preferably, for example, 37 parts by mass or less, 29 parts by mass or less, and 22 parts by mass or less with respect to 100 parts by mass of the rubber component.

The polymer material (D) having no diene skeleton in the molecular skeleton is preferably at least one selected from the group consisting of polybutene and acrylic resin. By blending these materials with the rubber composition according to the present invention, higher WET performance can be exhibited.

(Polybutene)
The polymer material (D) having no diene skeleton in the molecular skeleton in the present invention is preferably polybutene. Polybutene is produced by polymerizing 1-butene, and is preferably an unmodified homopolymer. When polybutene is used as the polymer material (D) having no diene skeleton in the molecular skeleton, the weight average molecular weight becomes relatively large, so that the WET performance is further improved. Further, polybutene is preferably liquid at room temperature.

The molecular weight of polybutene (weight average molecular weight) is preferably in the range of 1,000 to 50,000 from the viewpoint of wet performance, more preferably 3,000 to 20,000, more preferably 5,000 to 17,000, more preferably 6,000 to 15,000, and 6,500. ˜13000 is more preferable.

When polybutene is included as the polymer material (D) having no diene skeleton in the molecular skeleton, the amount of the polybutene added is 0.5 parts by mass or more and 40 parts by mass or more based on 100 parts by mass of the rubber component. It is preferable to include the following. More preferably, the total amount is 10 parts by mass or more and 30 parts by mass or less. When the amount of the polybutene mentioned above is 0.5 parts by mass or more with respect to 100 parts by mass of the rubber component, the WET performance is improved, while the amount of polybutene mentioned above is relative to 100 parts by mass of the rubber component. If it is 40 parts by mass or less, the rolling resistance is lowered.

(acrylic resin)
The polymer material (D) having no diene skeleton in the molecular skeleton in the present invention is also preferably an acrylic resin. The acrylic resin is a polymer having a repeating unit as a main skeleton derived from acrylic acid, methacrylic acid, or an ester derivative thereof (hereinafter, also referred to as an acrylic monomer) (hereinafter, also referred to as an acrylic polymer). .) and includes unmodified acrylic polymer and modified acrylic polymer. Therefore, the unmodified acrylic polymer and the modified acrylic polymer may be collectively referred to as "acrylic polymer". The acrylic resin may be used alone or in combination of two or more.

It should be noted that "having a repeating unit derived from an acrylic monomer as a main skeleton" means that when all the repeating units constituting the acrylic polymer are 100% by mass, the acrylic monomer is contained in the acrylic polymer. It means that the repeating units derived from the monomer are contained in a total amount of 50% by mass or more and 100% by mass or less. Further, the acrylic monomer may be one kind or plural kinds as long as the effect of the present invention is not impaired. The acrylic resin can be obtained by polymerizing at least one acrylic monomer.

The acrylic resin may be blended as it is, or may be blended as a rubber component, a filler, a resin, or the like supported on it, or a kneaded with these raw materials in advance (a master batch).

Here, the molecular weight (weight average molecular weight) of both the unmodified acrylic polymer and the modified acrylic polymer is preferably in the range of 1,000 to 50,000. This is because when the molecular weight of these acrylic polymers is 1000 or more, it is possible to prevent the acrylic polymer from coming off when applied to the tire, while when the molecular weight is 50,000 or less, the tire is Can be suppressed. From the same viewpoint, the molecular weight of these acrylic polymers is more preferably in the range of 1500 to 20000, and particularly preferably in the range of 1500 to 4500.

The acrylic resin described above is preferably one obtained by polymerizing a (meth)acrylic acid ester monomer as a main component, and may be polyacrylate or polymethacrylate, but is preferably polyacrylate. Here, "(meth)acrylic" is a general term meaning acrylic and methacrylic.

The number of carbon atoms in the ester portion of the (meth)acrylic acid ester is preferably 1 to 20, more preferably 1 to 10. The ester moiety may be linear, branched or cyclic. Specific examples of the (meth)acrylic acid ester include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, s-butyl acrylate, t-butyl acrylate, acrylic acid. Neopentyl, 2-ethylhexyl acrylate, isodecyl acrylate, lauryl acrylate, alkyl acrylates such as tridecyl acrylate and stearyl acrylate, cyclohexyl acrylate, isobornyl acrylate and alicyclic acrylate such as tricyclodecynyl acrylate Examples thereof include alkyl and methacrylic acid esters corresponding to these, and these can be used alone or in combination of two or more.

As the acrylic monomer, it is preferable to use any one or more of methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. It is also possible to copolymerize a copolymerizable monomer other than (meth)acrylic acid ester (for example, styrene) with (meth)acrylic acid ester.

Further, the acrylic resin in the present invention is preferably an acrylic polymer which is liquid at room temperature. However, except for the monomer for introducing the modifying group, the liquid acrylic polymer preferably contains only (meth)acrylic acid ester, and more preferably only acrylic acid ester.

The modified acrylic polymer preferably has at least one modified group selected from a hydroxyl group, an epoxy group and a carboxyl group.

This is because when the rubber composition containing the modified acrylic polymer is used for a tire, the WET performance in the latter stage of use is maintained at a higher level.

The modified acrylic polymer may include an acrylic polymer having a functional group introduced as a modifying group. The method of introducing a functional group into the acrylic polymer as a modifying group is not particularly limited. For example, by copolymerizing a vinyl monomer having a functional group with the (meth)acrylic acid ester, an acrylic polymer having a modifying group in its side chain can be obtained. Examples of such a functional group-containing monomer include hydroxyalkyl (meth)acrylates such as hydroxyethyl acrylate and hydroxybutyl acrylate; (meth)acrylic acid; glycidyl (meth)acrylate. It is not limited to these.

The acrylic resin in the present invention is an unmodified acrylic polymer and at least one modified acrylic polymer having at least one modified group selected from a hydroxyl group, an epoxy group and a carboxyl group. It is preferably an acrylic polymer.

These acrylic polymers have reactivity such as chemical bonding with silanol groups or affinity such as hydrogen bonding. Further, these acrylic polymers preferably include at least an acrylic polymer having an epoxy group.

In addition, in one of the embodiments of the present invention, it is selected from an unmodified acrylic polymer and a modified acrylic polymer having at least one modified group selected from a hydroxyl group, an epoxy group and a carboxyl group. WET performance when an acrylic polymer other than at least one acrylic polymer (hereinafter referred to as "other acrylic polymer") or a rubber composition containing process oil is applied to a tire. The effect of improving is reduced.

When an acrylic resin is included as the polymer material (D) having no diene skeleton in the molecular skeleton, the acrylic resin is included in a total amount of 0.5 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the rubber component. It is preferable that the total amount is 10 parts by mass or more and 30 parts by mass or less. When the amount of the acrylic resin compounded is 0.5 parts by mass or more based on 100 parts by mass of the rubber component, the WET performance is improved. On the other hand, when the blending amount of the above-mentioned acrylic polymer is 40 parts by mass or less with respect to 100 parts by mass of the rubber component, rolling resistance is lowered.

<Softener (E)>
The rubber composition according to the present invention contains a softening agent (E) in addition to the rubber component (A), the filler (B), the thermoplastic resin (C), and the polymer material (D) described above. Is preferred. By including the softening agent (E) in the rubber composition, flexibility can be further imparted, and thus the SNOW performance can be further improved.

Here, as the softening agent (E), aliphatic ester, phosphate ester, mineral oil derived from minerals, aromatic oil derived from petroleum, paraffin oil, naphthene oil, palm oil derived from natural products, sunflower oil, castor oil , Cottonseed oil, soybean oil and the like. The softening agents may be used alone or in combination of two or more. Further, the softening agent (E) is preferably a low-temperature softening agent capable of imparting flexibility to rubber in a low temperature range (for example, 0° C. or lower), and from such a viewpoint, an aliphatic ester, a phosphoric acid ester or sunflower oil. Is preferred. The softening agent (E) of the present application includes not only an oil as a compounding agent but also an oil as a polymer extending oil.

Examples of the aliphatic ester include monoesters and diesters of polyhydric alcohols (dihydric, trihydric or higher polyhydric alcohols) and higher fatty acids (higher fatty acids having 8 or more carbon atoms, preferably 8 to 30 carbon atoms). Alternatively, a polyvalent ester of more than that is preferable. For example, lauric acid ester, myristic acid ester, palmitic acid ester, stearic acid ester, oleic acid ester and oils containing them are preferable.

Examples of the phosphoric acid ester include tricresyl phosphate, phenyl dicresyl phosphate, xylenyl dicresyl phosphate, cresyl dixylenyl phosphate, triphenyl phosphate, tributyl phosphate, trichloroethyl phosphate, and trichloroethyl phosphate. Examples include octyl phosphate, triethyl phosphate, arylalkyl phosphate and the like.

In the rubber composition according to the present invention, the above-mentioned softening agent is preferably contained in a total amount of 1 part by mass or more, and more preferably 1 part by mass or more and 50 parts by mass with respect to 100 parts by mass of the rubber component (A). Including: When the compounding amount of the above-mentioned softening agent is 1 part by mass or more with respect to 100 parts by mass of the rubber component, SNOW performance is improved, while the compounding amount of the above-mentioned softening agent is based on 100 parts by mass of the rubber component. This is because when the total amount is 50 parts by mass or more, the rolling resistance is reduced.

<Inorganic particles (F)>
The rubber composition according to the present invention includes an inorganic component in addition to the rubber component (A), the filler (B), the thermoplastic resin (C), and the polymer material (D) having no diene skeleton in the molecular skeleton. It may further include particles (F).

The above-mentioned inorganic particles (F) are one kind of fillers, but are compounded for the purpose of imparting reinforcement such as breaking strength, high elastic modulus and abrasion resistance by mixing with a rubber component like a filler. Unlike the agent, it is preferable to include it in the rubber composition separately from the filler (B). By including the inorganic particles (F) in the rubber composition, the WET performance can be further improved.

The average primary particle size of the inorganic particles (F) in the present invention is preferably larger than the average primary particle size of the filler (B). Thereby, the WET performance can be further improved.

The ratio (b/f) of the average primary particle size (b) of the filler (B) to the average primary particle size (f) of the inorganic particles (F) in the present invention is preferably 0.0008 to 0.96, and 0 0.0012 to 0.92 is more preferable, 0.0016 to 0.87 is more preferable, and 0.0018 to 0.82 is still more preferable. In one form, 0.08 to 0.87 is more preferable, 0.12 to 0.82 is more preferable, 0.16 to 0.77 is more preferable, and 0.18 to 0.72 is further preferable. Moreover, in one form, 0.0016-0.1 is more preferable and 0.0018-0.09 is still more preferable. When the ratio of the average primary particle size of both is within the above range, the WET performance can be further improved.

Further, the ratio (BS/FS) of the BET specific surface area (BS) of the filler (B) to the BET specific surface area (FS) of the inorganic particles (F) in the present invention is preferably 1.2 to 15, and 1.4 -12 are more preferable. When the ratio of the BET specific surface areas of both is within the above range, the WET performance can be further improved.

As the inorganic particles (F), inorganic particles made of the same material as the filler (B) can be used. The inorganic particles (F) may be used alone or in combination of two or more kinds. Good. The inorganic particles (F) are preferably silica or aluminum hydroxide.

When the inorganic particles (F) are silica, the average primary particle diameter of the inorganic particles (F) is preferably 50 to 100 nm. When the average primary particle size of the inorganic particles (F) is in the range of 50 to 100 nm, the hydrophilicity of the tire surface is further improved.

Further, when the inorganic particles (F) are aluminum hydroxide, the average primary particle diameter of the inorganic particles (F) is preferably 0.5 to 5 μm. When the average primary particle diameter of the inorganic particles (F) is in the above range, the hydrophilicity of the tire surface is further improved.

The method for measuring the average particle diameter of the inorganic particles (F) is the same as the method for measuring the average particle diameter of silica.

The compounding amount of the inorganic particles (F) in the rubber composition according to the present invention is preferably 5 to 40 parts by mass, and more preferably 10 to 30 parts by mass with respect to 100 parts by mass of the rubber component (A). More preferable.

<Other ingredients>
The rubber composition according to the present invention includes the above-mentioned rubber component (A), filler (B), thermoplastic resin (C), and polymeric material (D) having no diene skeleton in the molecular skeleton, In addition to the softening agent (E) and/or the inorganic particles (F) optionally blended, other components may be contained to the extent that the effects of the invention are not impaired. As the other components, for example, vulcanizing agents, vulcanization accelerators, silane coupling agents, aging inhibitors, vulcanization accelerating aids, antiozonants, and surfactants, etc. are commonly used in the rubber industry. At least one selected from the group consisting of the additives described above may be appropriately contained.

(Vulcanizing agent)
The rubber composition according to the present invention comprises a rubber component (A), a filler (B), a thermoplastic resin (C), and a polymer material (D) having no diene skeleton in the molecular skeleton, It may further contain a sulfurizing agent. The vulcanizing agent is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include sulfur and bismaleimide compounds. The vulcanizing agents may be used alone or in combination of two or more.

The compounding amount of the vulcanizing agent is not particularly limited and can be appropriately adjusted according to the purpose. For example, 0.1 part by mass or more and 2.0 parts by mass or less is preferable with respect to 100 parts by mass of the rubber component. , 1.0 part by mass or more and 2.0 parts by mass or less are more preferable, and 1.2 parts by mass or more and 1.8 parts by mass or less are particularly preferable.

(Vulcanization accelerator)
The rubber composition according to the present invention may further contain a vulcanization accelerator if necessary. The vulcanization accelerator is not particularly limited and may be appropriately selected depending on the purpose, and is, for example, at least one selected from guanidines, sulfenamides, thiazoles, thiourea, and diethylthiourea. Preferably. The vulcanization accelerators may be used alone or in combination of two or more.

The compounding amount of the vulcanization accelerator is not particularly limited and can be appropriately adjusted depending on the purpose, and is, for example, 0.1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the rubber component. When the amount is 0.1 parts by mass or more, the effect of vulcanization is easily obtained, and when the amount is 20 parts by mass or less, excessive progress of vulcanization can be suppressed.

(Silane coupling agent)
When the rubber composition according to the present invention contains silica as a filler, it preferably further contains a silane coupling agent. By using the silane coupling agent, the effects of improving the dispersibility of silica, the workability during rubber processing, or the abrasion resistance can be obtained. The silane coupling agent may be used alone or in combination of two or more.

Examples of the silane coupling agent include bis(3-triethoxysilylpropyl) tetrasulfide (trade name "Si69" manufactured by Evonik Degussa), bis(3-triethoxysilylpropyl) trisulfide, bis(3 -Triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) tetrasulfide, bis(3-trimethoxysilylpropyl) tetrasulfide, bis(2-trimethoxysilylethyl) tetrasulfide, 3-mercaptopropyltrimethoxy Silane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl- N,N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothiazolyltetrasulfide, 3-triethoxysilylpropylbenzolyltetrasulfide , 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis(3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N -Dimethylthiocarbamoyl tetrasulfide, dimethoxymethylsilylpropyl benzothiazolyl tetrasulfide, 3-octanoylthiopropyltriethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyl Trimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, or 3-[ethoxybis(3,6,9,12,15-penta And oxaoctacosan-1-yloxy)silyl]-1-propanethiol (trade name “Si363” manufactured by Evonik Degussa Co., Ltd.) and the like. In addition, these silane coupling agents may be used individually by 1 type, and may be used in combination of 2 or more type.

The blending amount of the silane coupling agent varies depending on the type of the silane coupling agent and the like, but is preferably in the range of 1% by mass or more and 25% by mass or less with respect to the blending amount of silica, and 2% by mass or more. The range is more preferably 20% by mass or less, and particularly preferably 3% by mass or more and 18% by mass or less. By setting the amount of the silane coupling agent to be 1% by mass or more, the effect of reducing the heat buildup of the rubber composition can be easily obtained, and the effect as the coupling agent can be sufficiently exhibited. Further, by setting the blending amount to 25% by mass or less, gelation of the rubber component can be suppressed.

(Anti-aging agent)
As the antiaging agent, known ones can be used and are not particularly limited. For example, a phenol anti-aging agent, an imidazole anti-aging agent, an amine anti-aging agent, etc. can be mentioned. These antioxidants can be used alone or in combination of two or more.

(Vulcanization acceleration aid)
Examples of the vulcanization acceleration aid include zinc white (ZnO), fatty acids, and the like. The fatty acid may be saturated or unsaturated, linear or branched fatty acid, and the number of carbon atoms of the fatty acid is not particularly limited, but for example, has 1 to 30 carbon atoms, preferably 15 to 30 carbon atoms. Individual fatty acids, more specifically cyclohexanoic acid (cyclohexanecarboxylic acid), naphthenic acids such as alkylcyclopentane having a side chain; hexanoic acid, octanoic acid, decanoic acid (including branched carboxylic acids such as neodecanoic acid), Saturated fatty acids such as dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid (stearic acid); unsaturated fatty acids such as methacrylic acid, oleic acid, linoleic acid, linolenic acid; resin acids such as rosin, tall oil acid, abietic acid, etc. Is mentioned. These may be used alone or in combination of two or more. In the present invention, zinc white or stearic acid can be preferably used.

The method for producing the rubber composition according to the present invention is not particularly limited, and each component (rubber component, filler and other components) constituting the rubber composition is blended and kneaded. Can be obtained by

"tire"
The tire according to the present invention is characterized by using the rubber composition described above. Since the rubber composition is used, the tire of the present invention is excellent in SNOW performance, WET performance, low rolling resistance and steering stability.

Here, the site of the tire using the rubber composition according to the present invention is not limited as long as it is a rubber member forming the inside of the tire. For example, as the rubber member, a belt coating rubber, a carcass coating rubber, a tread portion (tread base rubber, etc.), a shoulder portion, a sidewall portion, a stiffener rubber in a bead portion, a rubber between belt layers, and a space between the tread portion and the belt. Examples of the rubber include a cushion rubber, a rubber between a belt and a carcass, a cushion rubber for a recycled tire, and a rubber for repairing a tire.

In the tire according to the present invention, it is preferable to use the rubber composition in the tread portion. By applying the rubber composition to the tread portion in contact with the road surface, SNOW performance, WET performance, low rolling characteristics, and steering stability can be maximized.

As a method for manufacturing the tire according to the present invention, a conventional method can be used. For example, the manufacturing method, a carcass layer containing an unvulcanized rubber on the tire forming drum, a belt, a member such as a tread that is normally used for tire production are sequentially laminated, and the drum is removed to obtain a green tire, and then, A desired tire (for example, a pneumatic tire) can be manufactured by heating and vulcanizing this green tire according to a conventional method.

Hereinafter, the present invention will be described in more detail with reference to examples, but these examples are intended to illustrate the present invention and do not limit the present invention in any way. Details of the materials used in the examples are as follows.

(*1) Modified conjugated diene polymer (i): Modified styrene-butadiene rubber (high TgSBR): Synthesized by the method described below, containing 10.0 parts by mass of oil component per 100 parts by mass of rubber component, weight average Molecular weight (Mw)=85.2×10 ⁴ , glass transition temperature (Tg)=−24° C.
(*2) Modified conjugated diene polymer (ii): Modified styrene/butadiene rubber (modified SBR) Synthesized by a method described later (*3) Modified conjugated diene polymer (iii): Modified styrene/butadiene rubber (low TgSBR ): Synthesized by the method described later (*4) Conjugated diene polymer (i): Styrene-butadiene rubber, product name “JSR 1500” manufactured by JSR Corporation
(*5) Conjugated diene polymer (ii): Natural rubber (NR) (RSS#3)
(*6) Conjugated diene polymer (iii): butadiene rubber, product name "BR01" manufactured by JSR Corporation
(*7) Silica (i) (fine particle size silica):
Tosoh Silica CTAB191, BET245 average primary particle size = 5 to 25 nm
(*8) Silica (ii) (general-purpose silica):
Product name “NipSil (registered trademark) AQ” CTAB165 manufactured by Tosoh Silica Corporation Average primary particle size=10 to 30 nm
(*9) Silica (iii) (large particle size silica): Tosoh Silica CTAB79 average primary particle size=20 to 40 nm
(*10) Carbon black: product name "#80" manufactured by Asahi Carbon Co., Ltd. average primary particle size 22 115
(* 11) a styrene-alkylene block copolymer: The total styrene content 52 wt% JSR Corporation, trade name "DYNARON (registered trademark) 9901P", the unit _{(C A)} and unit _{(C B)} and a unit for _(C A) Of 70% by mass
(*12) Polyester polyol: product name "Zeofine 100" manufactured by Nippon Zeon Co., Ltd.
(*13) Polybutene (i): Delim Co., Ltd. product name “HRPB2300”, Mw=5500
(*14) Polybutene (ii): JX Nikko Nisseki Energy Co., Ltd. product name “Nisseki Polybutene HV1900” Mw=8500
(*15) Polybutene (iii): Product name “Tetrax Grade 3T” manufactured by JX Nippon Oil & Energy Corporation Mw=47800
(*16) Acrylic resin (i): product name “ARUFON UP-1021” manufactured by Toagosei Co., Ltd., Mw=1600
(*17) Acrylic resin (ii): manufactured by Toagosei Co., Ltd., product name “ARUFON UP-1000”, Mw=3000
(*18) Acrylic resin (iii): manufactured by Toagosei Co., Ltd., trade name "ARUFON UP-1500", Mw=12000
(*19) Softener (i): Oil containing oleate ester Product name "Splender" manufactured by Kao Corporation
(*20) Softening agent (ii): trioctyl phosphate, trade name "TOP" manufactured by Daihachi Chemical Industry Co., Ltd.
(*21) Softener (iii): Sunflower oil (*22) Inorganic particles (i): Silica Tosoh Silica Co., Ltd. trade name “NipSil (registered trademark) EL” Average primary particle size=50 to 100 nm
(*23) Inorganic particles (ii): aluminum hydroxide manufactured by Showa Denko KK, trade name "Hijilite (registered trademark) H-43M" Average primary particle size = 0.5 to 10 m
(*24) Stearic acid (*25) ZnO
(*26) Anti-aging agent (6PPD): N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, trade name "Nocrac 6C" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
(*27) Anti-aging agent (TMDQ): Seiko Chemical Co., Ltd. product name "Nonflex RD-S"
(*28) Wax: Microcrystalline wax, product name “Ozoace 0701” manufactured by Nippon Seiro Co., Ltd.
(*29) Silane coupling agent: bis(3-triethoxysilylpropyl) tetrasulfide, trade name "Si69" manufactured by Evonik Degussa
(*30) Vulcanization accelerator (DPG): 1,3-diphenylguanidine, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. under the trade name "Noccer D"
(*31) Vulcanization accelerator (MBTS): di-2-benzothiazolyl disulfide, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. under the product name “Noxeller DM”
(*32) Vulcanization accelerator (CBS): N-cyclohexyl-2-benzothiazolesulfenamide, manufactured by Sanshin Chemical Industry Co., Ltd. under the trade name "Sunceller CM-G"
(*33) Sulfur In Table 1, the ratio (b/f) of the average primary particle diameter (b) of the filler (B) to the average primary particle diameter (f) of the inorganic particles (F) is 0.0008. Within the range of 0.96. In addition, in Table 1, the ratio (BS/FS) of the BET specific surface area (BS) of the filler (B) to the BET specific surface area (FS) of the inorganic particles (F) is in the range of 1.2 to 15. ..

"Modified conjugated diene polymer (i): Synthesis of modified SBR"
The internal volume is 10 L, the internal height (L) to diameter (D) ratio (L/D) is 4.0, the bottom has an inlet, the top has an outlet, and a tank reactor with a stirrer. A tank type pressure vessel having a stirrer and a temperature control jacket is used as a polymerization reactor. The water, which has been previously removed of water, is mixed under the conditions of 17.2 g/min of styrene, 10.5 g/min of styrene and 145.3 g/min of n-hexane. In a static mixer provided in the middle of a pipe for supplying the mixed solution to the inlet of the reaction group, 0.117 mmol/min of residual impurity inactivating n-butyllithium was added and mixed at the bottom of the reaction group. Supply continuously. Further, polymerization in which 2,2-bis(2-oxolanyl)propane as a polar substance is rapidly mixed with a stirrer at a rate of 0.019 g/min and n-butyllithium as a polymerization initiator at a rate of 0.242 mmol/min. It was fed to the bottom of the reactor to continuously continue the polymerization reaction. The temperature is controlled so that the temperature of the polymerization solution at the outlet of the top of the reactor is 75°C. When the polymerization was sufficiently stable, a small amount of the polymer solution before addition of the coupling agent was withdrawn from the outlet of the top of the reactor, and the antioxidant (BHT) was added so that the amount was 0.2 g per 100 g of the polymer, and then the solvent was added. Remove and measure Mooney viscosity at 110° C. and various molecular weights.

Next, 0.0302 mmol/min of tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine diluted to 2.74 mmol/L as a coupling agent was added to the polymer solution flowing out from the outlet of the reactor. A polymer solution to which a coupling agent was added was continuously added at a rate of water containing 5.2 ppm of water (n-hexane solution) and mixed by passing through a static mixer to cause a coupling reaction. At this time, the time until the coupling agent was added to the polymerization solution flowing out from the outlet of the reactor was 4.8 minutes, and the temperature was 68° C. The temperature in the polymerization step and the temperature until the modifier was added were Was 7°C. The antioxidant (BHT) was continuously added to the polymer solution subjected to the coupling reaction at 0.055 g/min (n-hexane solution) so that the amount was 0.2 g per 100 g of the polymer, and the coupling reaction was completed. To do. Simultaneously with the antioxidant, an oil (JOMO Process NC140 manufactured by JX Nippon Mining & Nisseki Energy Co., Ltd.) was continuously added to 100 g of the polymer so as to be 37.5 g, and mixed with a static mixer. The solvent is removed by steam stripping to obtain the modified SBR. As a result of measuring the microstructure of the obtained modified SBR (high TgSBR), the amount of bound styrene was 40% by mass, the amount of vinyl bond in the butadiene portion was 41%, the weight average molecular weight (Mw)=85.2×10 ⁴ , the molecular weight. Ratio of 200×10 ⁴ or more and 500×10 ⁴ or less=4.6% Contraction factor (g′)=0.59.

"Modified conjugated diene polymer (ii): Synthesis of modified SBR"
A cyclohexane solution of 1,3-butadiene and a cyclohexane solution of styrene were added to a dried, nitrogen-substituted 800 mL pressure-resistant glass container so that 70.2 g of 1,3-butadiene and 39.5 g of styrene were added, and 2,2 After adding 0.6 mmol of -ditetrahydrofurylpropane and 0.8 mmol of n-butyllithium, polymerization was performed at 50°C for 1.5 hours. In this case, 0.72 mmol of N-(1,3-dimethylbutylidene)-3-triethoxysilyl-1-propanamine was added as a modifier to the polymerization reaction system in which the polymerization conversion rate became almost 100%. A denaturing reaction was performed at 50° C. for 30 minutes. Thereafter, 2 mL of a solution of 2,6-di-t-butyl-p-cresol (BHT) in 5% by mass of isopropanol was added to stop the reaction, and the reaction product was dried according to a conventional method to obtain a modified SBR. As a result of measuring the microstructure of the obtained modified SBR, the amount of bound styrene was 35% by mass.

"Modified conjugated diene polymer (iii): Synthesis of modified SBR"
A cyclohexane solution of 1,3-butadiene and a cyclohexane solution of styrene were added to a pressure-resistant glass container of 800 mL that had been dried and purged with nitrogen so as to give 67.5 g of 1,3-butadiene and 7.5 g of styrene. After adding 0.6 mmol of -ditetrahydrofurylpropane and 0.8 mmol of n-butyllithium, polymerization was performed at 50°C for 1.5 hours. At this time, 0.72 mmol of N,N-bis(trimethylsilyl)-3-[diethoxy(methyl)silyl]propylamine was added as a modifier to the polymerization reaction system in which the polymerization conversion rate became almost 100%. A denaturing reaction was performed at 30° C. for 30 minutes. Thereafter, 2 mL of a solution of 2,6-di-t-butyl-p-cresol (BHT) in 5% by mass of isopropanol was added to stop the reaction, and the reaction product was dried according to a conventional method to obtain a modified SBR. As a result of measuring the microstructure of the obtained modified SBR (low TgSBR), the amount of bound styrene was 10% by mass, the amount of vinyl bond in the butadiene portion was 40%, and the peak molecular weight was 200,000.
<Examples 1 to 7 and Comparative Examples 1 to 4>
According to the formulation shown in Tables 1 and 2, a rubber composition is prepared using an ordinary Banbury mixer. Using the rubber composition as a tread rubber, a pneumatic radial tire for passenger cars having a size of 195/65R15 is produced according to a conventional method. The obtained tire was evaluated for SNOW performance, WET performance, low rolling resistance and steering stability by the following methods. The evaluation results are shown in Tables 1 and 2.

"SNOW performance evaluation method"
Four test tires were mounted on a domestic passenger car with a displacement of 1600 cc and the braking performance on ice (SNOW performance) at an ice temperature of -1°C was confirmed. The test tire using the sample of Example 1 is used as a control (100), and the SNOW performance index=(braking distance of test tire of Example 1/braking distance of each test tire)×100 is displayed as an index. The prediction evaluation results are shown in Tables 1-2. Note that the larger the index value, the better the SNOW performance.

"WET performance evaluation method"
The test tire is mounted on a test vehicle, and the steering stability is expressed by the driver's feeling score in an actual vehicle test on a wet road surface, and the tire feeling score of Example 1 is set to 100 and displayed as an index. The larger the index value, the better the WET performance.

"Evaluation method for low rolling resistance"
The test tire is rotated by a rotating drum at a speed of 80 km/hr, the load is set to 4.82 kN, and the rolling resistance is measured, and the reciprocal of the rolling resistance of the tire of Example 1 is set to 100 and expressed as an index. The larger the index value, the lower the rolling resistance and the better.

"Method for evaluating steering stability"
For each of the test tires, steering stability was evaluated based on the feeling of a test driver in an actual vehicle test on a dry road surface. The rubber compositions having the same composition are grouped, and each dry handling performance in Example 1 is represented as 100, and is indexed. The evaluation results are shown in Tables 1 and 2. The larger the index value, the better the steering stability of the tire.

As can be understood from the results of the examples and comparative examples, it was confirmed that the tires of the examples provided a highly parallel tire with SNOW performance, WET performance, low rolling resistance, and steering stability.

Claims (10)

A rubber component (A), a filler (B), a thermoplastic resin (C) containing at least one selected from the group consisting of a styrene/alkylene block copolymer and a polyester polyol resin having an aromatic ring, A polymer material (D) having no diene skeleton in the molecular skeleton,
In the rubber component (A), at least one selected from the group consisting of natural rubber, butadiene rubber and synthetic isoprene rubber is contained in a total amount of 10% by mass or more, and a modified conjugated diene polymer is contained in an amount of 5% by mass or more. Then
The polymer material (D) has a weight average molecular weight of 1,000 to 50,000,
0.5 to 40 parts by mass of each of the thermoplastic resin (C) and the polymer material (D), relative to 100 parts by mass of the rubber component (A), a rubber composition. The rubber composition according to claim 1, wherein the polymer material (D) is at least one selected from the group consisting of polybutene and acrylic resin. The rubber composition according to claim 2, wherein the polybutene is an unmodified homopolymer. Alkylene blocks of the styrene-alkylene block _{copolymers, - (CH 2 -CH (C} 2 H 5)) - units _{(C A)} and - _{(CH 2} -CH 2) - units _{(C B)} and the organic and the total content of the units _{(C a)} is, based on the total weight of the unit _{(C a)} and the unit _{(C B),} it is 40 mass% or more, any of claims 1 to 3 1 The rubber composition according to item. Alkylene blocks of the styrene-alkylene block _{copolymers, - (CH 2 -CH (C} 2 H 5)) - units _{(C A)} and - _{(CH 2} -CH 2) - units _{(C B)} and the organic and the total content of the units (C _a) is, based on the total weight of the unit (C _a) and the unit (C _B), is 60 mass% or more, and the styrene-alkylene block copolymerization The rubber composition according to any one of claims 1 to 4, wherein the total styrene content in the coalescence is 30% by mass or more. The rubber composition according to any one of claims 1 to 5, wherein the filler (B) contains at least silica. The rubber composition according to claim 6, wherein the filler (B) further contains carbon black, and the ratio of the silica in the total mass of the filler (B) is 75% by mass or more. The rubber composition according to any one of claims 1 to 7, further containing 1 part by mass or more of a softening agent (E) with respect to 100 parts by mass of the rubber component (A). The rubber composition according to any one of claims 1 to 8, further comprising 5 to 40 parts by mass of inorganic particles (F) with respect to 100 parts by mass of the rubber component (A). A tire using the rubber composition according to any one of claims 1 to 9.