JP2023025857A - Tire rubber composition and tire - Google Patents

Abstract

To provide a rubber composition for tires that can reversibly change tire performance in response to temperature changes, and can improve on-ice performance, and provide a tire.SOLUTION: A tire rubber composition comprises a mixture of a rubber component and silica surface-treated for pre-bonding to a temperature-responsive compound.SELECTED DRAWING: None

Description

The present disclosure relates to rubber compositions for tires and tires.

Conventionally, tires have been required to have various performances. Especially for all-season tires, it is desirable to be able to change tire performance in response to large changes in outside temperature and road surface conditions. It has received little attention so far.

As surface characteristics of tires, for example, depending on the temperature and environment, it is conceivable to increase the ice grip performance with a hydrophilic surface on ice at low temperatures, and increase the dry grip performance with a hydrophobic surface at high temperatures. Since the surface characteristics (contact angle with water) of materials depend on the formulation, temperature-responsive materials such as poly(N-isopropylacrylamide) (PNIPAM) are blended in order to impart temperature changes to the surface characteristics through formulation. It is envisioned that a method to However, as a result of intensive studies by the present inventors, such materials have poor compatibility with polymers for tires, have solubility in water at low temperatures, and dissolve in water in rainy weather or on ice. Since it disappears from the composition, it has been found that a new problem arises that reversible changes in surface properties cannot be imparted.

An object of the present disclosure is to solve the above problems and to provide a tire rubber composition that can reversibly change tire performance in response to temperature changes and improve on-ice performance, and a tire. do.

TECHNICAL FIELD The present disclosure relates to a rubber composition for a tire obtained by mixing a rubber component and surface-treated silica for pre-bonding with a temperature-responsive compound.

According to the present disclosure, the tire rubber composition is obtained by mixing the rubber component and the surface-treated silica for bonding with the temperature-responsive compound in advance, so that the tire performance is reversible in response to temperature changes. It is possible to change it dynamically, and it is possible to improve the performance on ice.

The present disclosure is a rubber composition for a tire obtained by mixing a rubber component and surface-treated silica (hereinafter also referred to as "surface-treated silica") for bonding with a temperature-responsive compound in advance. The rubber composition can reversibly change tire performance in response to temperature changes, and can improve on-ice performance. In addition, the performance on ice can be improved while maintaining good wear resistance, and the overall performance of performance on ice and wear resistance can also be improved.

(rubber component)
The rubber component that can be used in the rubber composition is not particularly limited, and rubbers used in the tire field can be used. For example, isoprene rubber, butadiene rubber (BR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), styrene-isoprene-butadiene copolymer rubber (SIBR), etc. A diene-based rubber and the like can be mentioned. Among them, isoprene-based rubber, BR, and SBR are preferable from the viewpoint of obtaining more effects.

The diene rubber may be non-modified diene rubber or modified diene rubber.
Modified diene rubbers include diene rubbers having functional groups that interact with fillers such as silica and carbon black. Specifically, terminal-modified diene-based rubber (terminal-modified diene-based rubber having the above-described functional group at the terminal) obtained by modifying at least one end of diene-based rubber with a compound (modifying agent) having the above-described functional group, A main chain modified diene rubber having the above functional group on the main chain, or a main chain terminal modified diene rubber having the above functional group on the main chain and terminal (for example, a main chain having the above functional group on at least one end) Main chain terminal modified diene rubber modified with the above modifier), modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule, and hydroxyl group or epoxy group introduced Terminal modified A diene-based rubber and the like can be mentioned. These may be used alone or in combination of two or more.

Examples of the functional group include functional groups containing at least one atom selected from the group consisting of a nitrogen atom, an oxygen atom, and a silicon atom. These may be used alone or in combination of two or more.

Examples of the functional groups include amino group, amido group, silyl group, alkoxysilyl group, isocyanate group, imino group, imidazole group, urea group, ether group, carbonyl group, oxycarbonyl group, mercapto group, sulfide group, disulfide group, sulfonyl group, sulfinyl group, thiocarbonyl group, ammonium group, imide group, hydrazo group, azo group, diazo group, carboxyl group, nitrile group, pyridyl group, alkoxy group, hydroxyl group, oxy group, epoxy group and the like. . In addition, these functional groups may have a substituent. Among them, amino group (preferably an amino group in which the hydrogen atom of the amino group is substituted with an alkyl group having 1 to 6 carbon atoms), alkoxy group (preferably 1 carbon atom 6 alkoxy groups) and alkoxysilyl groups (preferably alkoxysilyl groups having 1 to 6 carbon atoms) are preferred.

The isoprene rubber includes natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR, and the like. NR may be SIR20, RSS#3, TSR20, etc., and IR may be IR2200, etc., which are commonly used in the tire industry. Modified NR includes deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc. Modified NR includes epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc., modified IR Examples include epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, and the like. These may be used alone or in combination of two or more.

When the rubber composition contains an isoprene-based rubber, the content of the isoprene-based rubber in 100% by mass of the rubber component is preferably 20% by mass or more, more preferably 30% by mass or more, and still more preferably 40% by mass or more. . Although the upper limit of the content is not particularly limited, it is preferably 90% by mass or less, more preferably 70% by mass or less, and still more preferably 60% by mass or less. Within the above range, the effect tends to be obtained more favorably.

The BR is not particularly limited. BR), tin-modified butadiene rubber modified with a tin compound (tin-modified BR), and the like, which are commonly used in the tire industry. Commercially available BR products of Ube Industries, Ltd., JSR Corporation, Asahi Kasei Corporation, Zeon Corporation, etc. can be used. These may be used alone or in combination of two or more.

Both non-denatured BR and denatured BR can be used as BR.
Examples of modified BR include BR having the above functional groups.

From the viewpoint of performance on ice, the cis content of BR is preferably 80% by mass or more, more preferably 85% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more. In this specification, the cis content (cis-1,4-bond amount) is a value calculated from signal intensity measured by infrared absorption spectroscopy or NMR analysis.

When the rubber composition contains BR, the content of BR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 30% by mass or more, and still more preferably 40% by mass or more. The upper limit of the content is not particularly limited, but is preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. Within the above range, the effect tends to be obtained more favorably.

The SBR is not particularly limited, and for example, emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc. can be used. These may be used alone or in combination of two or more.

The styrene content of SBR is preferably 5.0% by mass or more, more preferably 10.0% by mass or more, still more preferably 15.0% by mass or more, and particularly preferably 20.0% by mass or more. The upper limit of the styrene content is preferably 60.0% by mass or less, more preferably 50.0% by mass or less, still more preferably 40.0% by mass or less, and particularly preferably 30.0% by mass or less. . Within the above range, the effect tends to be obtained more favorably.
In this specification, the styrene content of SBR is calculated by ¹ H-NMR measurement.

The vinyl content of SBR is preferably 5.0% by mass or more, more preferably 10.0% by mass or more, still more preferably 12.0% by mass or more, and particularly preferably 14.0% by mass or more. The vinyl content is preferably 50.0% by mass or less, more preferably 30.0% by mass or less, still more preferably 20.0% by mass or less, and particularly preferably 18.0% by mass or less. Within the above range, the effect tends to be obtained more favorably.
The vinyl content (1,2-bonded butadiene unit amount) can be measured by infrared absorption spectrometry.

From the viewpoint of obtaining better effects, the SBR desirably has a styrene content (% by mass) and a vinyl content (% by mass) that satisfy the following formulas.
Styrene content + vinyl content <50.0 wt%
The styrene content+vinyl content is preferably 45.0% by mass or less, more preferably 43.0% by mass or less, even more preferably 41.0% by mass or less, and particularly preferably 40.0% by mass or less. The lower limit is preferably 30.0% by mass or more, more preferably 33.0% by mass or more, still more preferably 35.0% by mass or more, and particularly preferably 36.0% by mass or more. Within the above range, the effect tends to be obtained more favorably.

Although the mechanism by which such effects are obtained is not necessarily clear, it is speculated as follows.
Since the temperature-responsive compound of the surface-treated silica makes the rubber surface hydrophilic at low temperatures, the friction on ice improves, and the compatibility with rubber decreases and the rubber softens, which also reduces the friction on ice. is expected to improve. Furthermore, by using SBR with a total amount of styrene content and vinyl content of less than a predetermined amount, sufficient strength required for handling stability and the like is imparted. Therefore, it is presumed that the tire performance can be reversibly changed in response to temperature changes, and that the performance on ice is significantly improved.

The styrene content and vinyl content of the SBR described above refer to the styrene content and vinyl content of the SBR when there is one type of SBR, and when there are multiple types of SBR, the average styrene content and average vinyl content means content.
The average styrene content of SBR can be calculated by {Σ (content of each SBR × styrene content of each SBR)}/total content of all SBRs. % SBR is 85% by weight and SBR with a styrene content of 25% by weight is 5% by weight, the average styrene content of the SBR is 39.2% by weight (=(85×40+5×25)/(85+5) ).
Similarly, the average vinyl content of SBR can be calculated by {Σ (content of each SBR × vinyl content of each SBR)}/total content of all SBRs. If SBR with a volume of 30% by weight is 85% by weight and SBR with a vinyl content of 20% by weight is 5% by weight, then the average vinyl content of the SBR is 29.4% by weight (=(85 x 30 + 5 x 20)/ (85+5)).

As SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., JSR Co., Ltd., Asahi Kasei Co., Ltd., Nippon Zeon Co., Ltd., etc. can be used.

SBR may be unmodified SBR or modified SBR.
Examples of modified SBR include SBR having the above functional groups.

When the rubber composition contains SBR, the content of SBR in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 40% by mass or more, still more preferably 50% by mass or more, and particularly preferably 60% by mass. % or more, preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the total content (% by mass) of isoprene-based rubber and BR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 20% by mass, from the viewpoint of obtaining better effects. Above, more preferably 30% by mass or more, particularly preferably 40% by mass or more, preferably 70% by mass or less, more preferably 60% by mass or less, still more preferably 50% by mass or less, particularly preferably 45% by mass % or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, from the viewpoint of obtaining better effects, SBR and isoprene rubber and/or BR are included, and the content of SBR in 100% by mass of the rubber component (% by mass), 100% by mass of the rubber component The total content (% by mass) of isoprene-based rubber and BR in the medium preferably satisfies the following formula.
Content of SBR > Total content of isoprene rubber and BR > 0

Although the mechanism by which such effects are obtained is not necessarily clear, it is speculated as follows.
Since the temperature-responsive compound of the surface-treated silica makes the rubber surface hydrophilic at low temperatures, the friction on ice improves, and the compatibility with rubber decreases and the rubber softens, which also reduces the friction on ice. is expected to improve. Furthermore, the use of a large amount of SBR provides sufficient strength necessary for steering stability and the like. Therefore, it is presumed that the tire performance can be reversibly changed in response to temperature changes, and that the performance on ice is significantly improved.

The ratio of SBR content/total content of isoprene rubber and BR is preferably 1.2 or more, more preferably 1.3 or more, still more preferably 1.4 or more, and particularly preferably 1.5 or more. The upper limit is preferably 4.0 or less, more preferably 3.0 or less, even more preferably 2.5 or less, and particularly preferably 2.0 or less. Within the above range, the effect tends to be obtained more favorably.

(surface-treated silica)
In the surface-treated silica (silica that has undergone a surface treatment to bond with a temperature-responsive compound in advance), the temperature-responsive compound is a conformational change in the polymer chain that accompanies hydration and dehydration in response to temperature changes in water. is reversibly generated, and the hydrophilicity and hydrophobicity are reversibly changed by changes in temperature. It is known that this reversible change is caused by a molecular structure having a hydrophilic group capable of forming a hydrogen bond and a hydrophobic group that is poorly compatible with water in one molecule.

The temperature-responsive polymer includes a polymer exhibiting a Lower Critical Solution Temperature (LCST) in water, and a polymer exhibiting an Upper Critical Solution Temperature (LCST) in water. Polymers exhibiting Solution Temperature (UCST, also referred to as upper critical solution temperature, upper critical solution temperature) are known. These may be used alone or in combination of two or more.

A polymer exhibiting LCST becomes hydrophobic at temperatures higher than the LCST as the intramolecular or intermolecular hydrophobic bond is strengthened and the polymer chains are aggregated. On the other hand, at temperatures below the LCST, the polymer chains bind water molecules and become hydrated, making them hydrophilic. In this way, reversible phase transition behavior is exhibited with the LCST as a boundary.
Conversely, a polymer exhibiting a UCST becomes hydrophobic and insoluble at a lower temperature than the UCST, and becomes hydrophilic and dissolves at a higher temperature than the UCST. Thus, reversible phase transition behavior is exhibited with the UCST as a boundary. It has a plurality of amide groups in its side chains, and is considered to exhibit UCST-type behavior due to intermolecular forces acting as a driving force of hydrogen bonds between side chains.
Among them, polymers exhibiting LCST are desirable from the viewpoint of obtaining more effects.

（式中、ｎは１～１０００の整数を表し、Ｒ^１、Ｒ^２及びＲ^３は、それぞれ独立に、水素原子又はヒドロカルビル基を表し、Ｒ^１及びＲ^２の少なくとも１つが水素原子ではなく、Ｒ^１とＲ^２とで環構造を形成してもよい。） Polymers exhibiting LCST are described below.
Polymers exhibiting LCST may be used alone or in combination of two or more.
The polymer exhibiting LCST is not particularly limited as long as it exhibits LCST, but poly(N-substituted (meth)acrylamide) is preferable, and a polymer represented by the following formula (I) is more preferable.

(wherein n represents an integer of 1 to 1000, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a hydrocarbyl group, at least one of R ¹ and R ² is not a hydrogen atom, R ¹ and R ² may form a ring structure.)

n is preferably 3 or more, more preferably 5 or more, still more preferably 10 or more, particularly preferably 20 or more, preferably 500 or less, more preferably 300 or less, still more preferably 150 or less, particularly preferably 80 or less , most preferably 40 or less, more preferably 30 or less. Within the above range, the effect tends to be obtained more favorably.

The number of carbon atoms in the hydrocarbyl groups of R ¹ and R ² is not particularly limited, but is preferably 1 or more, more preferably 2 or more, still more preferably 3 or more, preferably 20 or less, more preferably 18 or less, and still more preferably. is 14 or less, particularly preferably 10 or less, most preferably 6 or less, and most preferably 4 or less. Within the above range, the effect tends to be obtained more favorably.

Hydrocarbyl groups for R ¹ and R ² include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, neopentyl group and isopentyl group. , an n-hexyl group; a cycloalkyl group such as a cyclohexyl group; and an aryl group such as a methylphenyl group and an ethylphenyl group. Among them, an alkyl group and a cycloalkyl group are preferable, and an alkyl group is more preferable.

The number of carbon atoms in the ring structure formed by R ¹ and R ² is preferably 3 or more, more preferably 4 or more, and preferably 7 or less, more preferably 5 or less. Within the above range, the effect tends to be obtained more favorably.

The hydrocarbyl groups for R ¹ and R ² may be branched or unbranched, although branched is preferred.

R ¹ and R ² are preferably a hydrogen atom, an alkyl group (especially a branched alkyl group), a cycloalkyl group, or a ring structure formed by R ¹ and R ² , more preferably a combination shown in Table 1, hydrogen A combination of an atom and an alkyl group (especially a branched alkyl group) is more preferred, and a combination of a hydrogen atom and a propyl group (especially an isopropyl group) is particularly preferred.

The number of carbon atoms in the hydrocarbyl group of R ³ is not particularly limited, but is preferably 1 or more, preferably 5 or less, more preferably 3 or less, still more preferably 2 or less, and particularly preferably 1. Within the above range, the effect tends to be obtained more favorably.

The hydrocarbyl group for R ³ includes the same hydrocarbyl groups for R ¹ and R ² . Among them, an alkyl group is preferable.

The hydrocarbyl group at ^R3 may be branched or unbranched.

R ³ is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom.

Examples of the polymer represented by the above formula (I) include poly(N-isopropylacrylamide), poly(N-ethylacrylamide), poly(Nn-propylacrylamide), poly(N-ethyl, N- methylacrylamide), poly(N,N-diethylacrylamide), poly(N-isopropyl, N-methylacrylamide), poly(N-cyclopropylacrylamide), poly(N-acryloylpyrrolidine), poly(N-acryloylpiperidine) poly(N-alkylacrylamide) polymers such as;
Poly(N-isopropylmethacrylamide), poly(N-ethylmethacrylamide), poly(Nn-propylmethacrylamide), poly(N-ethyl, N-methylmethacrylamide), poly(N,N-diethylmethacrylamide) amide), poly(N-isopropyl, N-methylmethacrylamide), poly(N-cyclopropylmethacrylamide), poly(N-methacryloylpyrrolidine), poly(N-alkylmethacrylamide such as poly(N-methacryloylpiperidine) ) polymer; These may be used alone or in combination of two or more. Among them, poly(N-isopropylacrylamide) and poly(N,N-diethylacrylamide) are preferred, and poly(N-isopropylacrylamide) (PNIPAM) is more preferred.

PNIPAM is a heat sensitive material that exhibits large surface energy changes in response to small temperature changes. For example, N. Mori et al., Temperature Induced Changes in the Surface Wetability of SBR+PNIPA Films, 292, Macromol. Mater. Eng. 917, 917-22 (2007).
PNIPAM has a hydrophobic isopropyl group in the side chain and a hydrophilic amide bond at the base of the isopropyl group.
At temperatures lower than 32°C, amide bonds, which are hydrophilic moieties, and water molecules form hydrogen bonds and dissolve in water. , the isopropyl group, which is the hydrophobic portion of the side chain, strengthens the hydrophobic bond within and between the molecules, causing the polymer chains to aggregate and become insoluble in water.
Thus, the LCST, the switching temperature between the hydrophilic and hydrophobic states of PNIPAM, is about 32°C.
The contact angle of a water droplet placed on a PNIPAM polymer film changes dramatically with temperature above and below the LSCT. For example, the contact angle of a water droplet placed on a PNIPAM membrane ranges from approximately 60° (hydrophilic) below 32°C to greater than approximately 93° (hydrophobic) upon heating above 32°C.

（式中、ｍは１～１０００の整数を表し、Ｒ^４、Ｒ^５及びＲ^６は、それぞれ独立に、水素原子又はヒドロカルビル基を表す。） Poly(alkyl vinyl ether) can also be suitably used as the polymer exhibiting LCST, and for example, polymers represented by the following formula (A) are preferred. As a result, the effect tends to be obtained more favorably. These may be used alone or in combination of two or more.

(In the formula, m represents an integer of 1 to 1000, and R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or a hydrocarbyl group.)

m is preferably 3 or more, more preferably 5 or more, still more preferably 10 or more, particularly preferably 20 or more, preferably 500 or less, more preferably 300 or less, still more preferably 150 or less, particularly preferably 80 or less , most preferably 40 or less, more preferably 30 or less. Within the above range, the effect tends to be obtained more favorably.

The number of carbon atoms in the hydrocarbyl group of R ⁴ is not particularly limited, but is preferably 1 or more, more preferably 2 or more, preferably 20 or less, more preferably 18 or less, still more preferably 14 or less, and particularly preferably 10 or less. , most preferably 6 or less, and most preferably 4 or less. Within the above range, the effect tends to be obtained more favorably.

The number of carbon atoms in the hydrocarbyl groups of R ⁵ and R ⁶ is not particularly limited, but is preferably 1 or more, preferably 5 or less, more preferably 3 or less, still more preferably 2 or less, and particularly preferably 1. Within the above range, the effect tends to be obtained more favorably.

Hydrocarbyl groups for R ⁴ , R ⁵ and R ⁶ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group and neopentyl group. , isopentyl group and n-hexyl group; cycloalkyl groups such as cyclohexyl group; and aryl groups such as methylphenyl group and ethylphenyl group. Among them, an alkyl group and a cycloalkyl group are preferable, and an alkyl group is more preferable.

R ⁴ is preferably an alkyl group, R ⁵ and R ⁶ are preferably hydrogen atoms, more preferably R ⁴ is an ethyl group, and R ⁵ and R ⁶ are hydrogen atoms.

Examples of the polymer represented by the above formula (A) include poly(methyl vinyl ether), poly(ethyl vinyl ether), poly(propyl vinyl ether), poly(butyl vinyl ether), poly(pentenyl ether), poly(hexyl vinyl ether) ), poly(heptyl vinyl ether), poly(octyl ether), and the like. These may be used alone or in combination of two or more. Among them, poly(ethyl vinyl ether) (PEVE) is preferred.

（式中、ｍは１～１０００の整数を表し、Ｒ^７、Ｒ^８及びＲ^９は、それぞれ独立に、水素原子又はヒドロカルビル基を表す。） As the polymer exhibiting LCST, a polymer represented by the following formula (B) is also suitable. As a result, the effect tends to be obtained more favorably. These may be used alone or in combination of two or more.

(In the formula, m represents an integer of 1 to 1000, and R ⁷ , R ⁸ and R ⁹ each independently represent a hydrogen atom or a hydrocarbyl group.)

m is preferably 3 or more, more preferably 5 or more, still more preferably 10 or more, particularly preferably 20 or more, preferably 500 or less, more preferably 300 or less, still more preferably 150 or less, particularly preferably 80 or less , most preferably 40 or less, more preferably 30 or less. Within the above range, the effect tends to be obtained more favorably.

The number of carbon atoms in the hydrocarbyl group of ^R7 is not particularly limited, but is preferably 1 or more, more preferably 2 or more, preferably 20 or less, more preferably 18 or less, still more preferably 14 or less, and particularly preferably 10 or less. , most preferably 6 or less, and most preferably 4 or less. Within the above range, the effect tends to be obtained more favorably.

The number of carbon atoms in the hydrocarbyl groups of R ⁸ and R ⁹ is not particularly limited, but is preferably 1 or more, preferably 5 or less, more preferably 3 or less, still more preferably 2 or less, and particularly preferably 1. Within the above range, the effect tends to be obtained more favorably.

Hydrocarbyl groups for R ⁷ , R ⁸ and R ⁹ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group and neopentyl group. , isopentyl group and n-hexyl group; cycloalkyl groups such as cyclohexyl group; and aryl groups such as methylphenyl group and ethylphenyl group. Among them, an alkyl group and a cycloalkyl group are preferable, and an alkyl group is more preferable.

R ⁷ is preferably an alkyl group, R ⁸ and R ⁹ are preferably hydrogen atoms, more preferably R ⁷ is an n-propyl group or isopropyl group, and R ⁸ and R ⁹ are hydrogen atoms.

Examples of the polymer represented by the above formula (B) include poly(isopropylvinylacrylamide) (PNIPVM, ^R7 is an isopropyl group, ^R8 and ^R9 are hydrogen atoms), poly(n-propylvinylacrylamide). (PNNPAM, R ⁷ is n-propyl group, R ⁸ and R ⁹ are hydrogen atoms), poly(n-butylvinylacrylamide) (R ⁷ is n-butyl group, R ⁸ and R ⁹ are hydrogen atoms), Poly(tert-butylvinylacrylamide) (R ⁷ is a tert-butyl group, R ⁸ and R ⁹ are hydrogen atoms), Poly(sec-butylvinylacrylamide) (R ⁷ is a sec-butyl group, R ⁸ and R ⁹ is a hydrogen atom), poly (methyl vinyl acrylamide) (R ⁷ is a methyl group, R ⁸ and R ⁹ are a hydrogen atom), poly (ethyl vinyl acrylamide) (R ⁷ is an ethyl group, R ⁸ and R ⁹ are hydrogen atom), poly(n-pentylvinylacrylamide) (R ⁷ is an n-pentyl group, R ⁸ and R ⁹ are hydrogen atoms), poly(isopentylvinylacrylamide) (R ⁷ is an isopentyl group, R ⁸ and R ⁹ is a hydrogen atom). These may be used alone or in combination of two or more. Among them, PNIPVM, PNNPAM, poly(n-butylvinylacrylamide) and poly(tert-butylvinylacrylamide) are preferable, and PNIPVM and PNNPAM are more preferable.

（式（ＩＩ）～（ＩＶ）中、ｎは上記式（Ｉ）のｎと同様である。式（ＩＩＩ）中、Ｒは、ｎ－プロピル基、イソプロピル基又はエチル基から選択されるアルキル基である。） Examples of polymers exhibiting LCST other than the polymers represented by formulas (I), (A), and (B) include poly(N-vinyl-caprolactam) (LSCT) represented by formula (II) below. : about 31° C.), poly(2-alkyl-2-oxazoline) represented by the following formula (III) (LSCT is about 62° C. when R is an ethyl group, and about 62° C. when R is an isopropyl group. 36 ° C., about 25 ° C. when R is an n-propyl group), alkyl-substituted cellulose (for example, methyl cellulose represented by the following formula (IV) (LSCT: about 50 ° C.), hydroxypropyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose), poly (N-ethoxyethyl acrylamide) (LSCT: about 35 ° C.), poly (N-ethoxyethyl methacrylamide) (LSCT: about 45 ° C.), poly (N-tetrahydrofurfuryl acrylamide) ( LSCT: about 28° C.), poly(N-tetrahydrofurfuryl methacrylamide) (LSCT: about 35° C.), polyvinyl methyl ether, poly[2-(dimethylamino)ethyl methacrylate], poly(3-ethyl-N-vinyl -2-pyrrolidone), hydroxyl butyl chitosan, polyoxyethylene (20) sorbitan monostearate, polyoxyethylene (20) sorbitan monolaurate, polyoxyethylene (20) sorbitan monooleate, 2-6 ethylene glycols poly(ethylene glycol) methacrylate, polyethylene glycol-co-polypropylene glycol (preferably having 2 to 8 ethylene glycol units and 2 to 8 polypropylene units, more preferably compounds of formula (A) ), ethoxylated iso-C ₁₃ H ₂₇ -alcohols (preferably with a degree of ethoxylation of 4 to 8), polyethylene glycols with 4 to 50, preferably 4 to 20 ethylene glycol units, 4 to 30 Polypropylene glycol having 1, preferably 4 to 15 propylene glycol units, monomethyl, dimethyl, monoethyl and diethyl ethers of polyethylene glycol having 4 to 50, preferably 4 to 20 ethylene glycol units, 4 to 50 and monomethyl, dimethyl, monoethyl and diethyl ethers of polypropylene glycol having 1, preferably 4 to 20 propylene glycol units. These may be used alone or in combination of two or more.
(A) HO-[-CH ₂ -CH ₂ -O] _x -[-CH(CH ₃ )-CH ₂ -O] _y -[-CH ₂ -CH ₂ -O] _z -H
(Where y=3-10 and x and z=1-8, where y+x+z is 5-18)

(In formulas (II) to (IV), n is the same as n in formula (I) above. In formula (III), R is an alkyl group selected from an n-propyl group, an isopropyl group, or an ethyl group. is.)

Polymers exhibiting LCST other than the above include, for example, a copolymer of N-isopropylacrylamide and butyl acrylate, a block copolymer of N-isopropylacrylamide and polyethylene oxide, a copolymer of N-isopropylacrylamide and a fluorine monomer. Polymer, polymer composite of poly-N-acetylacrylamide and polyethylene oxide, polymer composite of poly-N-acetylacrylamide and polyacrylamide, copolymer of N-acetylacrylamide and acrylamide and polyacrylamide a polymer complex of N-acryloylglycinamide and N-acetylacrylamide, a copolymer of 2-methoxyethyl acrylate and N,N-dimethylacrylamide, a compound represented by the following formula 1 and N,N - copolymers with dimethylacrylamide, poly(N,N-dimethyl(acrylamidopropyl)ammonium propane sulfate), copolymers of N,N-diethylacrylamide and maleic anhydride, N,N-diethylacrylamide and fumaric Copolymer with dimethyl acid, copolymer of N,N-diethylacrylamide and hydroxyethyl methacrylate, copolymer of N,N-diethylacrylamide and butadiene, polyvinyl alcohol, hydrolyzate of polyvinyl alcohol and polyacrylamide polymer complex with, N-acryloyl asparagineamide polymer, N-acryloyl glutamine amide polymer, N-methacryloyl asparagine amide polymer, copolymer of N-acryloylglycinamide and biotin methacrylamide derivative, N-acryloyl Copolymer of glycinamide and N-acryloyl asparaginamide, biotin-immobilized temperature-responsive magnetic microparticles (N-acryloylglycinamide, methacrylated magnetic microparticles and microparticles obtained by reacting biotin monomers), poly(sulfobetaine methacrylamide), copolymer of N-vinyl-n-butylamide and maleic anhydride, copolymer of N-vinyl-n-butylamide and dimethyl fumarate, N-vinyl-n-butylamide and hydroxyethyl methacrylate copolymers, copolymers of N-vinyl-n-butylamide and butadiene, polyesteramides, polyetheramides, copolymers of ethylene oxide and propylene oxide, monoamines of copolymers of ethylene oxide and propylene oxide poly(lactide-co-glycolide)-polyethylene oxide-polylactide triblock Copolymers, copolymers of 2-methoxyethyl acrylate and acryloylmorpholine, copolymers of 2-methoxyethyl acrylate and N-vinylpyrrolidone, copolymers of 2-methoxyethyl acrylate and 2-hydroxyethyl acrylate , a copolymer of 2-methoxyethyl acrylate and methoxytriethylene glycol acrylate, poly[2-(2-ethoxyethoxy)ethyl acrylate], poly(2-(2-ethoxyethoxy)ethyl acrylate-co-2-( methoxyethoxy)ethyl methacrylate, poly(2-(N,N-dimethylaminoethyl) methacrylate), copolymer of N-vinylcaprolactam and hydroxyethyl methacrylate, copolymer of methyl vinyl ether and hydroxyethyl methacrylate, N- Vinylcaprolactam polymer, copolymer of N-vinylcaprolactam and maleic anhydride, copolymer of N-vinylcaprolactam and dimethyl fumarate, copolymer of N-vinylcaprolactam and butadiene, N-vinylcaprolactam and Copolymers of vinylpyrrolidine and glycidyl methacrylate, copolymers of N-vinylcaprolactam, vinylpyrrolidine and methacrylic acid, copolymers of N-vinylcaprolactam, vinylpyrrolidone and α,α-dimethyl-meta-isopropenylbenzyl isocyanate Copolymers, copolymers of N-vinylcaprolactam, vinylpyrrolidone and hydroxyethyl methacrylate, poly(1-ethyl-3-vinyl-2-imidazolidone), poly(1-methyl-3-vinyl-2-imidazolidone) , poly(1-n-propyl-3-vinyl-2-imidazolidone), poly(1-isopropyl-3-vinyl-2-imidazolidone), poly(1-acetyl-3-vinyl-2-imidazolidone), poly( 1-propionyl-3-vinyl-2-imidazolidone), a copolymer represented by the following formula 2, poly(N-vinyl-2-imidazolidone compound), a copolymer of 2-hydroxyethyl vinyl ether and vinyl acetate, diethylene glycol mono vinyl ether and vinyl acetate a copolymer of methyl vinyl ether and maleic anhydride, a copolymer of methyl vinyl ether and dimethyl fumarate, a carbamoylated polyamino acid, a polymer of a compound represented by the following formula 3, a polymer of the following formula 4 Polymers of the compound represented by, poly(orthoester) with pendant [N-(2-hydroxyethyl)-L-glutamine] groups, polyacetal-poly[N-(2-hydroxyethyl)-L-glutamine]-polyacetal Triblock copolymer, poly[N-(2-hydroxyethyl)-L-glutamine]-poly(orthoester)-poly[N-(2-hydroxyethyl)-L-glutamine] triblock copolymer, poly [N-(2-hydroxyethyl)-L-glutamine]-polyacetal diblock copolymer, amino-terminated poly[N-(2-hydroxyethyl)-L-glutamine], amino-terminated poly(orthoester), amino-terminated Examples include polyacetal, cellulose triacetate, magnetic nanoparticles, polystyrene having amino groups, and glycoluril polymers. These may be used alone or in combination of two or more.

The weight average molecular weight of the temperature-responsive polymer is preferably 330 or more, more preferably 560 or more, still more preferably 1130 or more, and preferably 57000 or less, more preferably 34000 or less, still more preferably 17000 or less. Within the above range, the effect tends to be obtained more favorably.

The phase transition temperature (lower critical solution temperature (LCST) or upper critical solution temperature (UCST)) of the temperature-responsive polymer is preferably −50° C. or higher, more preferably −40° C. or higher, and still more preferably −30° C. or higher. , particularly preferably -20 ° C. or higher, most preferably -10 ° C. or higher, most preferably 0 ° C. or higher, still most preferably 5 ° C. or higher, preferably 60 ° C. or lower, more preferably 50 ° C. or lower, further preferably is 40° C. or lower, particularly preferably 35° C. or lower, most preferably 30° C. or lower, most preferably 25° C. or lower, and most preferably 20° C. or lower. Within the above range, the effect tends to be obtained more favorably.
In this specification, the phase transition temperature of the temperature-responsive polymer is measured using a spectrophotometer with a temperature control function. A temperature-responsive polymer aqueous solution adjusted to 10% by mass was placed in a cell, covered with a parafilm to prevent evaporation, and a temperature sensor was attached in the cell. The experiment was conducted at .1° C., and the phase transition temperature was taken as the temperature at which the transmittance reached 90%.

The temperature-responsive compound can be synthesized by a known method, for example, a method of polymerizing a monomer by exposure to radiation, a method of solution polymerization, or the like. Also, "Anal. Chem. , 68, 100-105 (1996)”. Furthermore, a commercial item can also be used.

In the surface-treated silica (silica that has been surface-treated to bond with a temperature-responsive compound in advance), the silica (raw material silica that is subjected to surface treatment) is not particularly limited, and for example, dry silica (silicic anhydride) , wet silica (hydrous silicic acid), and the like. These may be used alone or in combination of two or more. Among them, wet-process silica is preferable because it has many silanol groups.

As silica, for example, products of Degussa, Rhodia, Tosoh Silica, Solvay Japan, Tokuyama, etc. can be used.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 50 m ² /g or more, more preferably 100 m ² /g or more, still more preferably 150 m ² /g or more. Also, the N ₂ SA is preferably 300 m ² /g or less, more preferably 250 m ² /g or less, still more preferably 230 m ² /g or less. Within the above range, the effect tends to be obtained more favorably.
The N ₂ SA of silica can be measured according to ASTM D3037-81.

In the surface-treated silica, a known method can be employed for bonding the temperature-responsive compound and silica. For example, a method of contacting a temperature-responsive compound and a silica dispersion (a dispersion of silica dispersed in a solvent such as water) to bond and react can be used.

During the bonding and reaction between the temperature responsive compound and silica, the amount of the temperature responsive compound added to 100 parts by mass of silica is preferably 40 parts by mass or more, more preferably 60 parts by mass or more, from the viewpoint of obtaining a greater effect. , more preferably 80 parts by mass or more, preferably 200 parts by mass or less, more preferably 180 parts by mass or less, and even more preferably 160 parts by mass or less.

From the viewpoint of bonding and reaction between the temperature responsive compound and silica, it is preferable to bring the temperature responsive compound and the silica dispersion into contact under predetermined pH conditions, for example. The pH is preferably 10.0 or less, more preferably 9.5 or less, still more preferably 9.0 or less, and preferably 6.5 or more, more preferably 7.0 or more, still more preferably 7.0 or more. 5 or more. In addition, adjustment of pH can be implemented by well-known methods, such as addition of an acid and an alkali.

The temperature during the bonding and reaction between the temperature-responsive compound and silica is preferably 10°C or higher, more preferably 15°C or higher, and is preferably 50°C or lower, more preferably 40°C or lower, and still more preferably 30°C. ℃ or less. The reaction time is preferably 60 minutes or longer, more preferably 120 minutes or longer, still more preferably 150 minutes or longer, and is preferably 24 hours or shorter, more preferably 18 hours or shorter, still more preferably 12 hours or shorter.

In the surface-treated silica produced by the bonding, reaction, etc., the amount of the temperature-responsive compound adhered to 100 parts by mass of silica is preferably 5 parts by mass or more, more preferably 10 parts by mass, from the viewpoint of obtaining a greater effect. Above, more preferably 20 parts by mass or more, preferably 50 parts by mass or less, more preferably 40 parts by mass or less.

In the rubber composition, the content of the surface-treated silica with respect to 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, still more preferably 10 parts by mass or more, and preferably 50 parts by mass. It is not more than 40 parts by mass, more preferably not more than 30 parts by mass, and particularly preferably not more than 20 parts by mass. Within the above range, the effect tends to be obtained more favorably.

(other silica materials)
The rubber composition uses the surface-treated silica as a silica material, but from the viewpoint of obtaining a greater effect, as another silica material, silica that has not been subjected to surface treatment for bonding with a temperature-responsive compound in advance ( hereinafter also referred to as “untreated silica”). Here, in this specification, the silica material is a material containing silica, and includes other silica-containing materials in addition to the surface-treated silica.

Examples of untreated silica include silica that has not been surface-treated. Examples of silica not subjected to surface treatment include the silica (dry process silica, wet process silica, etc.) used as a raw material for producing the surface-treated silica. Examples of untreated silica include silica that has undergone a surface treatment for bonding with a compound other than the temperature-responsive compound in advance. Among them, silica not surface-treated, such as the dry-process silica and the wet-process silica, is preferable. The N ₂ SA of untreated silica is preferably in the same range as the silica (raw material silica to be surface-treated).

Although the mechanism by which such effects are obtained is not necessarily clear, it is speculated as follows.
When both the surface-treated silica and the untreated silica are blended in the rubber component, the hydrophilicity of the surface-treated silica changes due to the temperature-responsive compound, and the rubber surface becomes hydrophilic at low temperatures. It is thought that the effect of the friction will increase and the friction on ice will improve. In addition, by becoming hydrophilic, the compatibility with rubber decreases, and the reinforcing property as a filler decreases, so the rubber softens, which is also considered to improve the friction on ice. Furthermore, by using untreated silica together, the strength required for steering stability and the like is sufficiently imparted. In addition, since the surface-treated silica is a material in which a temperature-responsive compound and silica are bonded together, elution in water is prevented, and grip performance on ice can be reversibly improved. Therefore, in the rubber composition obtained by mixing the surface-treated silica and the untreated silica, the tire performance can be reversibly changed in response to temperature changes, and the ice performance is significantly improved. guessed.

In the rubber composition, the content of the untreated silica with respect to 100 parts by mass of the rubber component is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, still more preferably 60 parts by mass or more, and preferably 100 parts by mass. It is not more than 90 parts by mass, more preferably not more than 80 parts by mass, and particularly preferably not more than 70 parts by mass. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the blending ratio of the surface-treated silica and the untreated silica (the content of the surface-treated silica (parts by mass)/the content of the untreated silica (parts by mass)) improves the effect. From the viewpoint of obtaining, 95/5 to 50/50 is preferable, 90/10 to 60/40 is more preferable, and 88/12 to 70/30 is still more preferable.

In the rubber composition, the total amount of the silica material (the total content of the surface-treated silica and the untreated silica) is preferably more than 40 parts by mass, more than 50 parts by mass, with respect to 100 parts by mass of the rubber component. More preferably, it exceeds 70 parts by mass or more, and particularly preferably more than 75 parts by mass. The upper limit of the content is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 120 parts by mass or less, and particularly preferably 100 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

(Silane coupling agent)
The rubber composition preferably contains a silane coupling agent.
The silane coupling agent is not particularly limited, and examples thereof include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, Bis (3-trimethoxysilylpropyl) tetrasulfide, bis (2-trimethoxysilylethyl) tetrasulfide, bis (2-triethoxysilylethyl) trisulfide, bis (4-trimethoxysilylbutyl) trisulfide, bis ( 3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) disulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) disulfide, bis(2-trimethoxysilylethyl) ) disulfide, bis(4-trimethoxysilylbutyl) disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3- sulfides such as triethoxysilylpropyl methacrylate monosulfide; 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane; vinyl-based such as methoxysilane; amino-based such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane; glycidoxy-based such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane; nitro-based such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane; and chloro-based such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane. These may be used alone or in combination of two or more. Among them, sulfide-based and mercapto-based are preferable because they are more effective.

Examples of silane coupling agents that can be used include products of Degussa, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azmax Co., Ltd., Dow Corning Toray Co., Ltd., and the like.

The content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, with respect to 100 parts by mass of the total amount of the silica material (the total content of the surface-treated silica and the untreated silica). Also, it is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

(other fillers)
The rubber composition may contain fillers other than the surface-treated silica and untreated silica.
Other fillers are not particularly limited, and materials known in the rubber field can be used. Examples include inorganic fillers such as carbon black, calcium carbonate, talc, alumina, clay, aluminum hydroxide, aluminum oxide, and mica. be done. Among them, carbon black is preferred.

In the rubber composition, the content of fillers (total content of fillers) is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and still more preferably 80 parts by mass with respect to 100 parts by mass of the rubber component. parts or more, particularly preferably 90 parts by mass or more. The upper limit of the content is preferably 200 parts by mass or less, more preferably 150 parts by mass or less, even more preferably 120 parts by mass or less, and particularly preferably 110 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the total amount of the silica material (the total content of the surface-treated silica and the untreated silica) in 100% by mass of the filler is preferably 50% by mass or more, preferably 80% by mass or more, and 85% by mass. % or more by mass is more preferable. Although the upper limit is not particularly limited, it is preferably 95% by mass or less, more preferably 93% by mass or less. Within the above range, the effect tends to be obtained more favorably.

Examples of carbon black that can be used in the rubber composition include, but are not limited to, N134, N110, N220, N234, N219, N339, N330, N326, N351, N550 and N762. Commercially available products include Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Corporation, Shin Nikka Carbon Co., Ltd., and Columbia Carbon Co., Ltd. can. These may be used alone or in combination of two or more.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is preferably 50 m ² /g or more, more preferably 70 m ² /g or more, and even more preferably 90 m ² /g or more. The N ₂ SA is preferably 200 m ² /g or less, more preferably 150 m ² /g or less, and even more preferably 130 m ² /g or less. Within the above range, the effect tends to be obtained more favorably.
The nitrogen adsorption specific surface area of carbon black is determined according to JIS K6217-2:2001.

In the rubber composition, the content of carbon black is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 8 parts by mass or more, and particularly preferably 10 parts by mass with respect to 100 parts by mass of the rubber component. Department or above. The upper limit of the content is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 20 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

(Plasticizer)
The rubber composition may contain a plasticizer.
As used herein, a plasticizer is a material that imparts plasticity to a rubber component, and liquid plasticizers (plasticizers that are liquid (liquid) at 25°C) and solid plasticizers (plasticizers that are solid at 25°C) are mentioned. These may be used alone or in combination of two or more.

The content of the plasticizer (the total content of the liquid plasticizer and the solid plasticizer) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and still more preferably 15 parts by mass with respect to 100 parts by mass of the rubber component. More preferably, it is 20 parts by mass or more. The upper limit of the content is preferably 80 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, still more preferably 30 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.
The plasticizer content also includes the amount of oil contained in rubber (oil-extended rubber) and sulfur (oil-containing sulfur).

Examples of liquid plasticizers include oils, liquid polymers (liquid resins, liquid diene polymers, etc.), essential oils derived from natural products such as turpentine, and ester plasticizers. Solid plasticizers include solid resins such as those commonly used in the tire industry that are solid (solid) at 25°C. These may be used alone or in combination of two or more. Among them, the liquid plasticizer is preferably at least one selected from the group consisting of oils, liquid polymers, and liquid resins, more preferably oils, and still more preferably process oils.

The above oils are not particularly limited, and process oils such as paraffinic process oils, aromatic process oils, and naphthenic process oils, low PCA (polycyclic aromatic) process oils such as TDAE and MES, vegetable oils and fats, and Conventionally known oils such as mixtures thereof can be used. These may be used alone or in combination of two or more. Among them, paraffinic process oils are preferred.

As oil, for example, Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., Japan Energy Co., Ltd., Orisoi Co., Ltd., H & R, Toyokuni Oil Mills Co., Ltd., Showa Shell Oil Co., Ltd., Fuji Kosan Co., Ltd. etc. products can be used.

Examples of liquid resins include terpene resins that are liquid at 25°C (including terpene phenolic resins and aromatic modified terpene resins), rosin resins, styrene resins, C5 resins, C5C9 resins, coumarone-indene resins ( coumarone and indene single resins), olefin resins, polyurethane resins, acrylic resins, and the like.

Examples of the liquid resin include Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical, Nichinuri Chemical Co., Ltd. ) Nippon Shokubai Co., Ltd., JXTG Energy Co., Ltd., Arakawa Chemical Co., Ltd., Taoka Chemical Co., Ltd., and other products can be used.

Examples of liquid diene-based polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), and liquid styrene-isoprene copolymer ( liquid SIR), liquid styrene-butadiene-styrene block copolymer (liquid SBS block polymer), liquid styrene-isoprene-styrene block copolymer (liquid SIS block polymer), and the like. These may be modified with a polar group at the terminal or main chain.

As the liquid diene-based polymer, for example, products of Sartomer Co., Ltd., Kuraray Co., Ltd., etc. can be used.

The content of the liquid plasticizer (preferably oil) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 15 parts by mass or more, and particularly preferably 20 parts by mass with respect to 100 parts by mass of the rubber component. Department or above. The upper limit of the content is preferably 80 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, still more preferably 30 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.
The content of the liquid plasticizer also includes the amount of oil contained in rubber (oil-extended rubber) and sulfur (oil-containing sulfur).

As solid plasticizers, solid resins commonly used in tire compounds can be used. Specifically, terpene-based resin, rosin resin, styrene-based resin, olefin-based resin, C5-based resin, C9-based resin, C5/C9-based resin, coumarone-based resin, indene-based resin, coumarone-indene-based resin, acrylic resin and urethane resin. These may be one type or a mixture of two or more types, and the resin itself may be a copolymer of monomer components derived from a plurality of sources.

Solid plasticizers include, for example, Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical, Nichinuri Chemical Co., Ltd. ) Nippon Shokubai Co., Ltd., JXTG Energy Co., Ltd., Arakawa Chemical Co., Ltd., Taoka Chemical Co., Ltd., and other products can be used.

The softening point of the resin is preferably 30°C or higher, more preferably 50°C or higher, still more preferably 80°C or higher, preferably 200°C or lower, more preferably 160°C or lower, and still more preferably 140°C. Below, it is 120 degrees C or less especially preferably. By setting it within the above range, there is a tendency that the above effect can be obtained more preferably.
In the present specification, the softening point of the resin is the temperature at which the softening point defined in JIS K 6220-1:2001 is measured with a ring and ball type softening point measuring device, and the ball descends.

The content of the solid plasticizer (preferably the resin) is preferably 30 parts by mass or less, more preferably 5 parts by mass or less, and still more preferably 2 parts by mass or less with respect to 100 parts by mass of the rubber component. It can be a department. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the compounding ratio between the content of the surface-treated silica and the content of the plasticizer (content (parts by mass) of the surface-treated silica per 100 parts by mass of the rubber component/said per 100 parts by mass of the rubber component The content (parts by mass) of the plasticizer is preferably 0.30 or more, more preferably 0.50 or more, still more preferably 0.70 or more, and particularly preferably 1.00 or more. The upper limit is preferably 2.50 or less, more preferably 2.00 or less, still more preferably 1.50 or less, and particularly preferably 1.30 or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the compounding ratio of the total amount of the silica material (total content of the surface-treated silica and the untreated silica) to the content of the plasticizer (the total amount of the silica material relative to 100 parts by mass of the rubber component ( parts by mass)/content (parts by mass) of the plasticizer with respect to 100 parts by mass of the rubber component) is preferably 2.5 or more, more preferably 3.5 or more, still more preferably 3.7 or more, and particularly preferably 4. .0 or more. The upper limit is preferably 6.0 or less, more preferably 5.5 or less, still more preferably 5.2 or less, and particularly preferably 5.0 or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the compounding ratio between the content of the surface-treated silica and the content of the liquid plasticizer (content (parts by mass) of the surface-treated silica per 100 parts by mass of the rubber component/per 100 parts by mass of the rubber component The content (parts by mass) of the liquid plasticizer is preferably 0.30 or more, more preferably 0.50 or more, still more preferably 0.70 or more, and particularly preferably 1.00 or more. The upper limit is preferably 2.50 or less, more preferably 2.00 or less, still more preferably 1.50 or less, and particularly preferably 1.30 or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the compounding ratio of the total amount of the silica material (the total amount of the surface-treated silica and the untreated silica) to the content of the liquid plasticizer (the total amount of the silica material relative to 100 parts by mass of the rubber component (parts by mass)/content (parts by mass) of the liquid plasticizer with respect to 100 parts by mass of the rubber component) is preferably 2.5 or more, more preferably 3.5 or more, still more preferably 3.7 or more, and particularly preferably is greater than or equal to 4.0. The upper limit is preferably 6.0 or less, more preferably 5.5 or less, still more preferably 5.2 or less, and particularly preferably 5.0 or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the compounding ratio between the content of the surface-treated silica and the total content of the liquid resin and the liquid diene-based polymer (the content of the surface-treated silica with respect to 100 parts by mass of the rubber component (parts by mass) / The total content (parts by mass) of the liquid resin and the liquid diene polymer with respect to 100 parts by mass of the rubber component is preferably 0.30 or more, more preferably 0.50 or more, still more preferably 0.70 or more, especially Preferably it is 1.00 or more. The upper limit is preferably 2.50 or less, more preferably 2.00 or less, still more preferably 1.50 or less, and particularly preferably 1.30 or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the compounding ratio of the total amount of the silica material (the total content of the surface-treated silica and the untreated silica) to the total content of the liquid resin and the liquid diene polymer (100 parts by mass of the rubber component The total amount (parts by mass) of the silica material / the total content (parts by mass) of the liquid resin and the liquid diene polymer relative to 100 parts by mass of the rubber component) is preferably 2.5 or more, more preferably 3.5 above, more preferably 3.7 or more, particularly preferably 4.0 or more. The upper limit is preferably 8.0 or less, more preferably 7.0 or less, still more preferably 6.0 or less, and particularly preferably 5.0 or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the compounding ratio between the content of the surface-treated silica and the content of the resin (content (parts by mass) of the surface-treated silica per 100 parts by mass of the rubber component/the resin per 100 parts by mass of the rubber component (parts by mass)) is preferably 1.0 or more, more preferably 1.5 or more, still more preferably 1.8 or more, and particularly preferably 2.0 or more. The upper limit is preferably 5.0 or less, more preferably 4.0 or less, still more preferably 3.5 or less, and particularly preferably 3.0 or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the compounding ratio of the total amount of the silica material (the total amount of the surface-treated silica and the untreated silica) and the content of the resin (the total amount of the silica material (mass parts)/content (parts by mass) of the resin per 100 parts by mass of the rubber component) is preferably 5.0 or more, more preferably 7.0 or more, even more preferably 7.5 or more, and particularly preferably 8.0. That's it. The upper limit is preferably 20.0 or less, more preferably 16.0 or less, still more preferably 12.0 or less, and particularly preferably 10.0 or less. Within the above range, the effect tends to be obtained more favorably.

The mechanism by which the above effects are obtained by adjusting the amount of surface-treated silica, the amount of untreated silica, the amount of plasticizer, the amount of liquid plasticizer, the amount of liquid resin, the amount of liquid diene-based polymer, the amount of resin, etc. is necessarily clear. not, but it is speculated as follows.
Due to the temperature-responsive compound of the surface-treated silica, the rubber surface becomes hydrophilic at low temperatures, so the friction on ice improves, and the compatibility with rubber decreases and the rubber softens, which also reduces the friction on ice. is expected to improve. In addition, the combined use of untreated silica provides sufficient strength necessary for steering stability and the like. Furthermore, by mixing the amount of surface-treated silica, the amount of untreated silica, the amount of plasticizer, the amount of liquid plasticizer, the amount of liquid resin, the amount of liquid diene-based polymer, and the amount of resin in a predetermined ratio, it is possible to reduce friction on ice. It is considered that a higher improvement effect can be obtained. Therefore, it is presumed that the tire performance can be reversibly changed in response to temperature changes, and that the performance on ice is significantly improved.

(other materials)
The rubber composition preferably contains sulfur.
Sulfur includes powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersible sulfur, soluble sulfur and the like commonly used in the rubber industry. These may be used alone or in combination of two or more.

As sulfur, for example, products of Tsurumi Chemical Industry Co., Ltd., Karuizawa Io Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexis Co., Ltd., Nippon Kantan Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

The sulfur content is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and still more preferably 0.8 parts by mass or more with respect to 100 parts by mass of the rubber component. The content is preferably 10 parts by mass or less, more preferably 7 parts by mass or less, even more preferably 5 parts by mass or less, particularly preferably 3 parts by mass or less, and most preferably 2 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

The rubber composition preferably contains a vulcanization accelerator.
Vulcanization accelerators include thiazole vulcanization accelerators such as 2-mercaptobenzothiazole and di-2-benzothiazolyl disulfide; tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), tetrakis (2 -ethylhexyl) thiuram-based vulcanization accelerators such as thiuram disulfide (TOT-N); N-cyclohexyl-2-benzothiazolylsulfenamide, Nt-butyl-2-benzothiazolylsulfenamide, N-oxy Sulfenamide-based vulcanization accelerators such as ethylene-2-benzothiazolesulfenamide and N,N'-diisopropyl-2-benzothiazolesulfenamide; guanidines such as diphenylguanidine, diorthotolylguanidine and orthotolylbiguanidine system vulcanization accelerators. These may be used alone or in combination of two or more. Among them, a sulfenamide-based vulcanization accelerator is preferable.

As the vulcanization accelerator, for example, products manufactured by Kawaguchi Kagaku Co., Ltd., Ouchi Shinko Kagaku Co., Ltd., Rhein Chemie Co., etc. can be used.

The content of the vulcanization accelerator is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass, based on 100 parts by mass of the rubber component. Part by mass or less. Within the above range, the effect tends to be obtained more favorably.

The rubber composition preferably contains stearic acid.
As the stearic acid, conventionally known ones can be used, for example, products of NOF Corporation, Kao Corporation, Fuji Film Wako Pure Chemical Industries, Ltd., Chiba Fatty Acids Co., Ltd., etc. can be used.

The stearic acid content is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the rubber component. Also, the above content is preferably 5 parts by mass or less, more preferably 3 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

The rubber composition may contain zinc oxide.
As the zinc oxide, conventionally known ones can be used, for example, products of Mitsui Kinzoku Mining Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

The content of zinc oxide is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass, relative to 100 parts by mass of the rubber component. It is below. Within the above range, the effect tends to be obtained more favorably.

The rubber composition may contain an antioxidant.
Examples of anti-aging agents include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4′-bis(α,α′-dimethylbenzyl)diphenylamine; -Isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N'-di-2-naphthyl-p-phenylenediamine, etc. p-phenylenediamine-based antioxidants; quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; 2,6-di-t-butyl-4-methylphenol, monophenolic anti-aging agents such as styrenated phenol; inhibitors and the like. These may be used alone or in combination of two or more. Among them, p-phenylenediamine anti-aging agents and quinoline anti-aging agents are preferred, and p-phenylenediamine anti-aging agents are more preferred.

As the anti-aging agent, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Kagaku Kogyo Co., Ltd., Flexis, etc. can be used, for example.

The content of the anti-aging agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass, relative to 100 parts by mass of the rubber component. It is below the department. Within the above range, the effect tends to be obtained more favorably.

The rubber composition may contain wax.
The wax is not particularly limited, and includes petroleum waxes such as paraffin wax and microcrystalline wax; natural waxes such as plant waxes and animal waxes; synthetic waxes such as polymers of ethylene and propylene. These may be used alone or in combination of two or more.

As the wax, for example, products of Ouchi Shinko Kagaku Kogyo Co., Ltd., Nippon Seiro Co., Ltd., Seiko Kagaku Co., Ltd., etc. can be used.

The wax content is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the rubber component. Moreover, the content is preferably 10 parts by mass or less, more preferably 7 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

In addition to the above components, the rubber composition may contain additives commonly used in the tire industry, such as vulcanizing agents other than sulfur (e.g., organic cross-linking agents, organic peroxides), etc. can be exemplified. The content of each of these components is preferably 0.1 parts by mass or more and preferably 200 parts by mass or less with respect to 100 parts by mass of the rubber component.

The rubber composition can be produced, for example, by kneading the above components using a rubber kneading device such as an open roll mixer or a Banbury mixer, followed by vulcanization.

As for the kneading conditions, the kneading temperature is usually 100 to 180°C, preferably 120 to 170°C in the base kneading step for kneading additives other than the cross-linking agent (vulcanizing agent) and the vulcanization accelerator. In the finishing kneading step of kneading the vulcanizing agent and the vulcanization accelerator, the kneading temperature is usually 120°C or lower, preferably 80 to 110°C. A composition obtained by kneading a vulcanizing agent and a vulcanization accelerator is usually subjected to vulcanization treatment such as press vulcanization. The vulcanization temperature is generally 140-190°C, preferably 150-185°C.

The rubber composition can be used, for example, in tire members (as a rubber composition for tires), and is particularly preferably used in treads (cap treads).

A tire of the present disclosure is manufactured by a conventional method using the above rubber composition. That is, a rubber composition blended with various additives as necessary is extruded in an unvulcanized stage according to the shape of each tire member such as a tread, and is put on a tire building machine by a normal method. After molding and bonding together with other tire members to form an unvulcanized tire, the tire can be manufactured by heating and pressurizing in a vulcanizer.

The tire is not particularly limited, and examples thereof include a pneumatic tire, a solid tire, an airless tire, and the like. Among them, pneumatic tires are preferred.

The above tires include tires for passenger cars, tires for large passenger cars, tires for large SUVs, tires for heavy loads (tires for trucks and buses, etc.), tires for motorcycles, tires for racing, winter tires (studless tires, snow tires, stud tires). , all-season tires, run-flat tires, aircraft tires, mining tires, etc. Among them, it is suitable for winter tires and all-season tires because of its good performance on ice, and especially for all-season tires because it can reversibly change tire performance in response to temperature changes. It can be used preferably.

Various chemicals used in the following examples and comparative examples are collectively described below.
SBR1: Nipol 1502 (E-SBR, styrene content: 23.5% by mass, vinyl content: 16% by mass) manufactured by Nippon Zeon Co., Ltd.
SBR2: SL563 manufactured by JSR Corporation (styrene content 20% by mass, vinyl content 55.5% by mass)
BR: BR150B (cis content: 98% by mass) manufactured by Ube Industries, Ltd.
NR: TSR20 (natural rubber)
Carbon black: SEAST N220 (N ₂ SA: 111 m ² /g, DBP: 115 ml/100 g) manufactured by Mitsubishi Chemical Corporation
Silica (untreated silica): Ultrasil VN3 from Evonik Tegussa (silica without surface treatment, N ₂ SA: 175 m ² /g)
Surface-treated silica 1: Production Examples 1-1 to 1-2 below
Surface-treated silica 2: Production Examples 2-1 and 2-2 below
Silane coupling agent: Si266 (bis(3-triethoxysilylpropyl) disulfide) manufactured by Evonik Tegussa
Wax: Ozoace wax manufactured by Nippon Seiro Co., Ltd. Antioxidant: Nocrac 6C (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine manufactured by Ouchi Shinko Chemical Industry Co., Ltd.) )
Oil: PS-32 manufactured by Idemitsu Kosan Co., Ltd.
Liquid diene-based polymer: Lycon 150 manufactured by Sartomer (liquid butadiene polymer, Mn5200)
Resin: SYLVARES SA85 manufactured by Arizona Chemical Co. (a copolymer of α-methylstyrene and styrene, softening point 85° C.)
Stearic acid: Zinc stearate manufactured by NOF Corporation Zinc oxide: Zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. Type 2 Sulfur: Powdered sulfur manufactured by Tsurumi Chemical Co., Ltd. Vulcanization accelerator: Ouchi Shinko Kagaku Kogyo Co., Ltd. ) manufactured by Noxceler NS (N-tert-butyl-2-benzothiazolylsulfenamide)

<Production Example 1-1 Synthesis of PNIPAM>
11.32 g of N-isopropylacrylamide (NIPAM monomer) was added to a nitrogen-purged glass flask, 25 mL of toluene was added, and the mixture was stirred at room temperature for 30 minutes to form a uniform solution. After adding 1.10 g of butyronitrile (AIBN), the mixture was refluxed for 3 hours to react. The reaction solution was subjected to thin-layer chromatography (carrier: silica gel) to confirm the disappearance of spots of the starting NIPAM monomer (Rf value 0.8) and the appearance of new spots derived from the NIPAM polymer (PNIPAM). After distilling off the toluene solvent from the reaction solution using a rotary evaporator, the remaining white powder was dried under reduced pressure at a degree of vacuum of 0.1 Pa or less at 80° C. for 8 hours to obtain PNIPAM with a yield of 95%.
After making an aqueous solution of PNIPAM with water to a concentration of 1% by mass, the aqueous PNIPAM solution was heated from 20°C to 40°C and the appearance was checked. It was confirmed. Mw was 2000.

<Production Example 1-2 Production of surface-treated silica 1>
Under the following reaction conditions, 10 g of PNIPAM obtained in Production Example 1-1 and 100 g of an aqueous silica dispersion (silica concentration: 10% by mass) prepared by mixing silica and water were mixed and stirred, and PNIPAM and silica were mixed. The bonding (reaction) was allowed to proceed, and surface-treated silica 1 (adhesion amount of temperature-responsive compound to 100 parts by mass of silica: 20 parts by mass) was produced.
(Reaction conditions)
Temperature: 25°C
Time: 12 hours pH: 7.5

<Production Example 2-1 Synthesis of PNNPAM>
An NNPAM polymer (PNNPAM) was synthesized in the same manner as in Production Example 1-1 above, except that Nn-propylacrylamide (NNPAM monomer) was used instead of N-isopropylacrylamide.

<Production Example 2-2 Production of surface-treated silica 2>
Surface-treated silica 2 (adhesion amount of temperature-responsive compound to 100 parts by mass of silica) was prepared in the same manner as in Production Example 1-2, except that PNNPAM was used instead of PNIPAM.

<Examples and Comparative Examples>
Chemicals other than sulfur and vulcanization accelerators were kneaded for 5 minutes at 150° C. using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd. according to the formulations shown in Tables 2 to 4, A kneaded product was obtained. Next, sulfur and a vulcanization accelerator were added to the resulting kneaded material, and the mixture was kneaded at 80° C. for 5 minutes using an open roll to obtain an unvulcanized rubber composition.
The obtained unvulcanized rubber composition was press-vulcanized at 170° C. for 12 minutes to obtain a vulcanized rubber composition sheet having a thickness of 2 mm.
Further, using the obtained unvulcanized rubber composition, it is molded according to the shape of the cap tread, laminated with other tire members to produce an unvulcanized tire, and vulcanized at 170 ° C. for 15 minutes. A test tire (size: 195/65R15) was obtained.

The obtained vulcanized rubber compositions and test tires were stored at room temperature in a dark place for three months, and then evaluated as follows. The results are shown in Tables 2, 3 and 4. Comparative examples 1-1, 2-1, and 3-1 were used as reference comparative examples in Tables 2, 3, and 4, respectively.

<Abrasion resistance>
For the vulcanized rubber composition, using a Lambourn abrasion tester manufactured by Iwamoto Seisakusho Co., Ltd., the wear amount was measured at a surface rotation speed of 50 m / min, an additional load of 3.0 kg, a sand fall rate of 15 g / min, and a slip rate of 20%. were measured, and the reciprocals of these wear amounts were taken. The reciprocal of the wear amount of the reference comparative example was set to 100, and the reciprocals of the other wear amounts were expressed as indices. A larger index indicates better wear resistance.

<Ice Performance>
Using the test tire, the actual vehicle performance on snow and ice was evaluated under the following conditions (test conditions: temperature on ice -2 to -6°C, temperature on snow -3 to -10°C). The test tire was mounted on a domestically produced 2000 cc FR vehicle, and the stopping distance on ice required to depress the lock brake at a speed of 30 km/h and stop was measured. Then, using the reference comparative example as a reference, it was indexed by the following formula. A larger index indicates better performance on ice.
(Performance on ice) = (braking stopping distance of reference comparative example) / (stopping distance) x 100

The rubber compositions of the examples obtained by mixing the rubber component and the silica subjected to a surface treatment to bond with the temperature-responsive compound in advance have a hydrophilic rubber surface at low temperatures and improve performance on ice. It has been found that it is possible to reversibly change tire performance in response to temperature changes.

Further, in the examples, the performance on ice was improved, and the overall performance of performance on ice and abrasion resistance (represented by the sum of the two indices of performance on ice and abrasion resistance) was excellent.

The present disclosure (1) is a rubber composition for a tire obtained by mixing a rubber component and silica subjected to a surface treatment for bonding with a temperature-responsive compound in advance.

The present disclosure (2) is the rubber composition for tires according to the present disclosure (1), which contains silica that has not been surface-treated.

The present disclosure (3) includes styrene-butadiene rubber, and the styrene content (mass%) and vinyl content (mass%) of the styrene-butadiene rubber satisfy the following formulas (1) or (2) according to the present disclosure. A rubber composition for tires.
Styrene content + vinyl content <50.0 wt%

The present disclosure (4) includes a styrene-butadiene rubber and an isoprene-based rubber and/or butadiene rubber, and the content of the styrene-butadiene rubber and the total content of the isoprene-based rubber and the butadiene rubber satisfy the following formula: A tire rubber composition according to any one of disclosures (1) to (3).
Content of styrene-butadiene rubber>Total content of isoprene-based rubber and butadiene rubber>0

The present disclosure (5) is the tire rubber composition according to any one of the present disclosures (1) to (4), wherein the total amount of the silica material and the content of the plasticizer satisfy the following formula.
3.5 ≤ total amount of silica material / content of plasticizer ≤ 5.5

The present disclosure (6) is the tire rubber composition according to any one of the present disclosures (1) to (5), wherein the total amount of the silica material and the content of the liquid plasticizer satisfy the following formula.
3.5≦total amount of silica material/content of liquid plasticizer≦5.5

The present disclosure (7) is the tire rubber according to any one of the present disclosure (1) to (6), wherein the total amount of the silica material and the total content of the liquid resin and the liquid diene polymer satisfy the following formula. composition.
3.5 ≤ total amount of silica material/total content of liquid resin and liquid diene-based polymer ≤ 7.0

The present disclosure (8) is the tire rubber composition according to any one of the present disclosures (1) to (7), wherein the total amount of the silica material and the content of the resin satisfy the following formula.
7.0 ≤ total amount of silica material / content of resin ≤ 16.0

The present disclosure (9) is the tire rubber composition according to any one of the present disclosures (1) to (8), wherein the total amount of the silica material exceeds 50 parts by mass with respect to 100 parts by mass of the rubber component.

(10) of the present disclosure is a tire having a tread made of the rubber composition according to any one of (1) to (9) of the present disclosure.

(11) of the present disclosure is the tire according to (10) of the present disclosure, which is an all-season tire.

Claims (11)

A rubber composition for a tire obtained by mixing a rubber component and silica subjected to a surface treatment for bonding with a temperature-responsive compound in advance. 2. The rubber composition for tires according to claim 1, which contains silica which has not been surface-treated. The rubber composition for a tire according to claim 1 or 2, comprising a styrene-butadiene rubber, wherein the styrene content (% by mass) and the vinyl content (% by mass) of the styrene-butadiene rubber satisfy the following formulae.
Styrene content + vinyl content <50.0 wt% 4. Any one of claims 1 to 3, comprising styrene-butadiene rubber and isoprene-based rubber and/or butadiene rubber, wherein the content of said styrene-butadiene rubber and the total content of said isoprene-based rubber and butadiene rubber satisfy the following formula: The rubber composition for tires according to .
Content of styrene-butadiene rubber>Total content of isoprene-based rubber and butadiene rubber>0 The rubber composition for tires according to any one of claims 1 to 4, wherein the total amount of the silica material and the content of the plasticizer satisfy the following formula.
3.5 ≤ total amount of silica material / content of plasticizer ≤ 5.5 The rubber composition for tires according to any one of claims 1 to 5, wherein the total amount of the silica material and the content of the liquid plasticizer satisfy the following formula.
3.5≦total amount of silica material/content of liquid plasticizer≦5.5 The rubber composition for tires according to any one of claims 1 to 6, wherein the total amount of the silica material and the total amount of the liquid resin and the liquid diene-based polymer satisfy the following formula.
3.5 ≤ total amount of silica material/total content of liquid resin and liquid diene-based polymer ≤ 7.0 The rubber composition for tires according to any one of claims 1 to 7, wherein the total amount of the silica material and the content of the resin satisfy the following formula.
7.0 ≤ total amount of silica material / content of resin ≤ 16.0 The rubber composition for tires according to any one of claims 1 to 8, wherein the total amount of said silica material exceeds 50 parts by mass with respect to 100 parts by mass of said rubber component. A tire having a tread made of the rubber composition according to any one of claims 1 to 9. A tire according to claim 10, which is an all-season tire.