JP2018002940A - Rubber composition for tire and tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for tire which is excellent in operation stability and scorch resistance, and a tire using the rubber composition for tire.SOLUTION: A rubber composition for tire is a compound that contains a diene rubber, silica, a silane coupling agent and a cationic surface active agent, where the silane coupling agent is a compound represented by formula (1), the cationic surface active agent is quaternary ammonium salt having an amide bond or a carboxylic acid ester bond, a content of the silica is 50-200 pts.mass with respect to 100 pts.mass of the diene rubber, a content of the silane coupling agent is 4-15 pts.mass with respect to 100 pts.mass of the diene rubber, and a content of the cationic surface active agent is 0.05-10 pts.mass with respect to 100 pts.mass of the diene rubber.SELECTED DRAWING: None

Description

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

In recent years, there has been a demand for reducing tire rolling resistance in order to improve fuel efficiency during vehicle travel. Therefore, a method is known in which diene rubber constituting the tread portion of the tire is mixed with silica to reduce hysteresis loss (particularly tan δ at high temperature) to reduce heat generation and reduce tire rolling resistance. Yes.
However, since silica has low affinity with diene rubbers and high cohesiveness between silicas, silica is not dispersed even if silica is simply blended with diene rubbers, reducing the rolling resistance of tires. There was a problem that could not be obtained sufficiently.

  Under such circumstances, for example, Patent Document 1 discloses a rubber composition using 3-octanoylthio-1-propyltriethoxysilane as a silane coupling agent, and the rubber composition is excellent in low rolling resistance. Have been described.

JP 2006-232881 A

In recent years, in addition to the above-mentioned low rolling resistance, further improvement in handling stability (for example, rigidity) is required from the viewpoint of safety and the like. Further, from the viewpoint of productivity and the like, further improvement in scorch resistance is also demanded.
Under these circumstances, the present inventors examined a rubber composition using 3-octanoylthio-1-propyltriethoxysilane as a silane coupling agent based on Patent Document 1, and found that steering stability and scorch resistance were improved. It has become clear that does not necessarily meet the level required recently.

  In view of the above circumstances, an object of the present invention is to provide a tire rubber composition excellent in steering stability and scorch resistance, and a tire using the tire rubber composition.

As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by using a specific silane coupling agent and a specific cationic surfactant together, and have reached the present invention.
That is, the present inventors have found that the above problem can be solved by the following configuration.

(1) Contains a diene rubber, silica, a silane coupling agent, and a cationic surfactant,
The silane coupling agent is a compound represented by the following formula (1),
The cationic surfactant is a quaternary ammonium salt having an amide bond or a carboxylic ester bond,
The content of the silica is 50 to 200 parts by mass with respect to 100 parts by mass of the diene rubber.
The content of the silane coupling agent is 4 to 15 parts by mass with respect to 100 parts by mass of the diene rubber.
A tire rubber composition, wherein the content of the cationic surfactant is 0.05 to 10 parts by mass with respect to 100 parts by mass of the diene rubber.
(2) The rubber composition for tires according to (1), wherein the silica has a CTAB adsorption specific surface area of 190 to 300 m ² / g.
(3) A tire manufactured using the tire rubber composition according to (1) or (2).

  As shown below, according to the present invention, it is possible to provide a tire rubber composition excellent in steering stability and scorch resistance, and a tire using the tire rubber composition.

It is a partial section schematic diagram of the tire showing an example of an embodiment of a tire of the present invention.

The tire rubber composition of the present invention and the tire of the present invention are described below.
In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Rubber composition for tire]
The rubber composition for tires of the present invention (hereinafter also referred to as “the composition of the present invention”) contains a diene rubber, silica, a silane coupling agent, and a cationic surfactant.
Here, the said silane coupling agent is a compound represented by Formula (1) mentioned later. The cationic surfactant is a quaternary ammonium salt having an amide bond or a carboxylic ester bond. Further, the content of the silica is 50 to 200 parts by mass with respect to 100 parts by mass of the diene rubber, and the content of the silane coupling agent is 4 with respect to 100 parts by mass of the diene rubber. The content of the cationic surfactant is 0.05 to 10 parts by mass with respect to 100 parts by mass of the diene rubber.
Since the composition of this invention takes such a structure, it is thought that a desired effect is acquired. The reason is not clear, but it is thought to be as follows.

From the study of the present inventors, when 3-octanoylthio-1-propyltriethoxysilane is used as a silane coupling agent, the dispersibility of silica is improved by connecting the rubber and silica, but the rubber Has been found to be cut and the stiffness may be reduced.
In the composition of the present invention, an amide bond or a carboxylic ester bond is used as a cationic surfactant together with a compound represented by the formula (1) described later as a silane coupling agent (hereinafter also referred to as “specific silane coupling agent”). Since the quaternary ammonium salt having (hereinafter also referred to as “specific cation surfactant”) is used in combination, the specific cation surfactant assists the connection between the rubber and the silica, thereby suppressing a decrease in rigidity. It is considered to show excellent handling stability.
In addition, when 3-octanoylthio-1-propyltriethoxysilane is used as the silane coupling agent, scorch is likely to occur due to the high reactivity of the mercapto group generated from 3-octanoylthio-1-propyltriethoxysilane. In the invention, since the amide bond or carboxylic acid ester bond of the specific cationic surfactant stabilizes the mercapto group appropriately, the composition of the present invention is considered to have excellent scorch resistance.

  Hereinafter, each component contained in the composition of the present invention will be described.

[Diene rubber]
The diene rubber contained in the composition of the present invention is not particularly limited, and specific examples thereof include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), aromatic vinyl-conjugated diene copolymer. Examples include coal rubber, acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), and chloroprene rubber (CR). The diene rubber may be a single diene rubber or a combination of two or more diene rubbers.

As the diene rubber, aromatic vinyl-conjugated diene copolymer rubber is preferably used for the reason that the effects of the present invention are more excellent, and butadiene rubber (BR) is used in combination with the aromatic vinyl-conjugated diene copolymer. More preferably.
Examples of the aromatic vinyl-conjugated diene copolymer rubber include styrene butadiene rubber (SBR) and styrene isoprene copolymer rubber. Among these, styrene butadiene rubber (SBR) is preferable because the rigidity of the obtained tire is excellent.

The aromatic vinyl content (for example, styrene content) of the aromatic vinyl-conjugated diene copolymer is preferably 20 to 45% by mass for the reason that the effect of the present invention is more excellent, and 23 to 42% by mass. % Is more preferable.
The vinyl bond content in the conjugated diene of the aromatic vinyl-conjugated diene copolymer is preferably 10 to 50%, more preferably 25 to 48%, because the effect of the present invention is more excellent. More preferred. Here, the amount of vinyl bonds refers to the ratio of 1,2-vinyl bonds among cis-1,4-bonds, trans-1,4-bonds and 1,2-vinyl bonds, which are conjugated dienes. Say.

The said aromatic vinyl-conjugated diene copolymer is not specifically limited about the manufacturing method, It can manufacture by a conventionally well-known method.
Moreover, the aromatic vinyl and conjugated diene as a monomer used when manufacturing the said aromatic vinyl-conjugated diene copolymer are not specifically limited.
Here, examples of the conjugated diene monomer include 1,3-butadiene, isoprene (2-methyl-1,3-butadiene), 2,3-dimethyl-1,3-butadiene, and 2-chloro-1. , 3-butadiene, 1,3-pentadiene and the like.
On the other hand, examples of the aromatic vinyl monomer include styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, α-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, Examples include 4-tert-butylstyrene, divinylbenzene, tert-butoxystyrene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl ether, N, N-dimethylaminoethylstyrene, and vinylpyridine.

The content in the case of using the aromatic vinyl-conjugated diene copolymer is preferably 50 to 100% by mass of the diene rubber, and is preferably 55 to 95% by mass, because the rigidity of the obtained tire is excellent. More preferably, it is more preferably 60 to 90% by mass.
Further, when the butadiene rubber (BR) is used in combination with the aromatic vinyl-conjugated diene copolymer, the content of the butadiene rubber (BR) is the reason why the effect of the present invention is more excellent, It is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, and further preferably 20 to 40% by mass.

  The weight average molecular weight of the diene rubber (particularly the aromatic vinyl-conjugated diene copolymer) is not particularly limited, but is preferably 100,000 to 1,500,000 from the viewpoint of handling, More preferably, it is 000-1,300,000. In addition, the weight average molecular weight (Mw) of diene rubber shall be measured by standard polystyrene conversion by the gel permeation chromatography (GPC) which uses tetrahydrofuran as a solvent.

  The Tg (glass transition temperature) of the diene rubber (especially the aromatic vinyl-conjugated diene copolymer) is not particularly limited, but is −70 to −10 ° C. because the effect of the present invention is more excellent. Is more preferable, and it is more preferably −40 to −20 ° C.

〔silica〕
The silica contained in the composition of the present invention is not particularly limited, and any conventionally known silica compounded in a rubber composition for uses such as tires can be used. Examples thereof include wet silica, dry silica, fumed silica, diatomaceous earth, and the like. As the silica, one type of silica may be used alone, or two or more types of silica may be used in combination.
Although the CTAB (cetyltrimethylammonium bromide) adsorption specific surface area of silica is not particularly limited, it is preferably 140 to 300 m ² / g, more preferably 190 to 300 m ² / g, because the effect of the present invention is more excellent. More preferred.
In the present specification, the CTAB adsorption specific surface area is a value obtained by measuring the CTAB adsorption amount on the silica surface in accordance with JIS K6217-3: 2001 “Part 3: Determination of specific surface area—CTAB adsorption method”.

  In the composition of the present invention, the content of silica is 50 to 200 parts by mass with respect to 100 parts by mass of the diene rubber. Especially, since the effect of this invention is more excellent, it is preferable that it is 70-150 mass parts.

〔Silane coupling agent〕
The silane coupling agent contained in the composition of the present invention is a compound (specific silane coupling agent) represented by the following formula (1).

In the above formula (1), R ¹ represents an alkoxy group, R ² represents an alkyl group, R ³ represents an alkylene group, R ⁴ represents an alkyl group, and m represents an integer of 1 to 3.

In the above formula (1), R ¹ represents an alkoxy group. The alkyl group forming the alkoxy group may be linear, branched or cyclic. The number of carbon atoms of the alkoxy group is not particularly limited, but is preferably 1 to 10, and more preferably 1 to 3.

In the above formula (1), R ² represents an alkyl group (linear, branched or cyclic). Although carbon number in particular of an alkyl group is not restrict | limited, It is preferable that it is 1-10, and it is more preferable that it is 1-3. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group. Group, decyl group, dodecyl group, cyclopentyl group, cyclohexyl group and the like.

In the above formula (1), R ³ represents an alkylene group. The number of carbon atoms of the alkylene group is not particularly limited, but is preferably 1 to 10, and more preferably 2 to 5. Specific examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, an octamethylene group, a decamethylene group, and a dodecamethylene group.

In the above formula (1), R ⁴ represents an alkyl group (linear, branched or cyclic). Although carbon number in particular of an alkyl group is not restrict | limited, It is preferable that it is 1-22, and it is more preferable that it is 5-18. Specific examples of the alkyl group are as described above.

In said formula (1), m represents the integer of 1-3. Especially, it is preferable that it is 2 or 3 from the reason which the effect of this invention is more excellent, and it is more preferable that it is 3.
In the above formula (1), “m” represents the number of R ¹ bonded to the silicon atom, and “3-m” represents the number of R ² bonded to the silicon atom.

  Specific examples of the compound represented by the above formula (1) include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, and 3-lauroylthio. Propyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoylthiopropyl Trimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthio Ethyltrimethoxysilane, 2- deca Neu thio ethyltrimethoxysilane, and 2-lauroyl thio ethyl trimethoxysilane.

  In the composition of the present invention, the content of the specific silane coupling agent is 4 to 15 parts by mass with respect to 100 parts by mass of the diene rubber. Especially, it is preferable that it is 6-15 mass parts from the reason which the effect of this invention is more excellent.

  In the composition of the present invention, the content of the specific silane coupling agent is preferably 1 to 20% by mass and more preferably 6 to 15% by mass with respect to the content of the silica.

  In addition, a specific silane coupling agent may be used individually by 1 type, and may use 2 or more types together.

[Cationic surfactant]
The cationic surfactant (cationic surfactant) contained in the composition of the present invention is an amide bond (—NR—CO—, where R represents a hydrogen atom or a substituent (preferably a hydrocarbon group)). Alternatively, it is a quaternary ammonium salt (specific cationic surfactant) having a carboxylic ester bond (—O—CO—). Among these, a quaternary ammonium salt having an amide bond is preferable because the effect of the present invention is more excellent. The quaternary ammonium salt is preferably a salt of a quaternary ammonium ion and a halide ion (fluoride ion, chloride ion, bromide ion, iodide ion, etc.).
In the present specification, the cationic surfactant is a surfactant having only a cationic (cationic) dissociating group as a dissociating group, and a cationic (cationic) dissociating group and an anion as dissociating groups. So-called amphoteric surfactants having both sex (anionic) dissociating groups are not included.

<Quaternary ammonium salt having an amide bond>
The number of amide bonds contained in the quaternary ammonium salt having an amide bond is preferably 2 or more and 4 or less from the viewpoint of silica adsorption and silica dispersibility.

  As a suitable aspect of the quaternary ammonium salt having the amide bond, for example, a compound represented by the following formula (P1) can be mentioned.

In the above formula (P1), R ¹ represents a hydrocarbon group having 1 to 8 carbon atoms or a group represented by the following formula (P2), R ² represents an alkylene group, R ³ represents an acyl group, R ⁴ represents a methyl group, an ethyl group or a benzyl group, X represents a halogen atom, and m represents a number of 1 to 3.

In the above formula (P2), ^{R 5} represents a hydrogen atom or an acyl group, ^{R 6} represents a hydrogen atom or a methyl radical, n represents a number of 1-3.

In the above formula (P1), R ¹ represents a hydrocarbon group having 1 to 8 carbon atoms or a group represented by the above formula (P2). Examples of the hydrocarbon group having 1 to 8 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, secondary butyl group, t-butyl group, pentyl group, isopentyl group, and secondary pentyl group. T-pentyl group, hexyl group, secondary hexyl group, heptyl group, secondary heptyl group, octyl group, secondary octyl group, 2-methylpentyl group, 2-ethylhexyl group, vinyl group, allyl group, propenyl group, Examples include butenyl group, isobutenyl group, pentenyl group, isopentenyl group, hexenyl group, heptenyl group, octenyl group, cyclohexyl group, phenyl group, methylphenyl group, and benzyl group.

In the above formula (P2), R ⁵ represents a hydrogen atom or an acyl group. In the present invention, an acyl group refers to a residue obtained by removing OH from a monovalent carboxylic acid. Such carboxylic acids include acetic acid, propionic acid, butanoic acid, pentanoic acid, isopentanoic acid, caproic acid (hexanoic acid), heptanoic acid, caprylic acid (octanoic acid), nonanoic acid, capric acid (decanoic acid), lauric acid Saturated fatty acids such as acids (undecanoic acid), myristic acid (tetradecanoic acid), palmitic acid (hexadecanoic acid), stearic acid (octadecanoic acid), arachidic acid (eicosanoic acid), behenic acid (docosanoic acid), tetracosanoic acid, hexacosanoic acid Unsaturated fatty acids such as oleic acid, linoleic acid, linolenic acid, elaidic acid and erucic acid; hydroxy fatty acids such as ricinoleic acid and hydroxystearic acid;

In the above formula (P2), R ⁶ represents a hydrogen atom or a methyl group, and n represents a number of 1 to 3 (preferably an integer of 1 to 3). R ⁶ is preferably a hydrogen atom and n is preferably 1 because of its superior adsorptivity to silica.

In the above formula (P1), R ¹ is preferably a methyl group or an ethyl group, and more preferably a methyl group, from the viewpoint of adsorptivity to silica.

In the above formula (P1), R ² represents an alkylene group. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a hexamethylene group, an octamethylene group, and the like. Since the adsorbability to silica is excellent and the industrial availability of the raw material is easy, R ² is ethylene. Group and propylene group are preferred.

In the above formula (P1), R ³ represents an acyl group, and examples of the carboxylic acid corresponding to the acyl group include the carboxylic acids exemplified for R ⁵ in the above formula (P2). From the standpoints of adsorptivity to silica and silica dispersibility, fatty acids having 8 to 22 carbon atoms are preferred, and fatty acids having 10 to 18 carbon atoms are more preferred. R ⁴ represents a methyl group, an ethyl group or a benzyl group, and is preferably a methyl group from the viewpoint of adsorptivity to silica. X represents a halogen atom, and examples of the halogen atom include a chlorine atom, a bromine atom, and an iodine atom. X is preferably a chlorine atom from the viewpoint of adsorptivity to silica. m represents a number of 1 to 3 (preferably an integer of 1 to 3), and m is preferably 2 from the viewpoint of adsorption to silica and dispersibility of silica. In the case where a plurality of acyl groups are present in the compound represented by the formula (P1), they may be the same group or different groups.

<Quaternary ammonium salt having carboxylate bond>
The number of carboxylic acid ester bonds of the quaternary ammonium salt having a carboxylic acid ester bond is preferably 2 or more and 4 or less from the viewpoint of silica adsorption and silica dispersibility.

  As a suitable aspect of the quaternary ammonium salt having a carboxylic acid ester bond, for example, a compound represented by the following formula (Q1) can be mentioned.

In the above formula (Q1), ^{R 1} represents a hydrocarbon group having 1 to 8 carbon atoms, ^{R 2} represents an alkylene group, ^{R 3} represents an acyl group, ^{R 4} is a methyl group, an ethyl group or a benzyl group X represents a halogen atom, and m represents a number of 1 to 3.

In the above formula (Q1), R ¹ represents a hydrocarbon group having 1 to 8 carbon atoms. Specific examples of the hydrocarbon group having 1 to 8 carbon atoms are the same as R ¹ in formula (P1) described above. R ¹ is preferably a methyl group or an ethyl group, and more preferably a methyl group, from the viewpoint of adsorptivity to silica.

In the above formula (Q1), R ² represents an alkylene group. Specific examples and preferred embodiments of R ² is the same as R ² in the above-mentioned formula (P1).

In the above formula (Q1), R ³ represents an acyl group, and examples of the carboxylic acid corresponding to the acyl group include the carboxylic acids exemplified for R ⁵ in the above formula (P2). From the standpoints of adsorptivity to silica and silica dispersibility, fatty acids having 8 to 22 carbon atoms are preferred, and fatty acids having 10 to 18 carbon atoms are more preferred. R ⁴ represents a methyl group, an ethyl group or a benzyl group, and is preferably a methyl group from the viewpoint of adsorptivity to silica. X represents a halogen atom, and examples of the halogen atom include a chlorine atom, a bromine atom, and an iodine atom. X is preferably a chlorine atom from the viewpoint of adsorptivity to silica. m represents a number of 1 to 3 (preferably an integer of 1 to 3), and m is preferably 2 from the viewpoint of adsorption to silica and dispersibility of silica. In the case where a plurality of acyl groups are present in the compound represented by the formula (Q1), they may be the same group or different groups.

  In the composition of the present invention, the content of the specific cationic surfactant is 0.05 to 10 parts by mass with respect to 100 parts by mass of the diene rubber described above. It is preferable that it is 0.1-5 mass parts. In addition, a specific cationic surfactant may be used individually by 1 type, and may use 2 or more types together.

[Optional ingredients]
<Glycerin partial fatty acid ester>
It is preferable that the composition of this invention contains glycerol partial fatty acid ester with the specific cationic surfactant mentioned above from the reason which the effect of this invention is more excellent. Since the glycerin partial fatty acid ester improves the dispersibility of the specific cationic surfactant, as a result, the dispersibility of the silica is further increased, and the above-described effects of the present invention are further improved. In the present invention, the partial fatty acid ester refers to a compound in which a part of hydroxyl groups of a polyhydric alcohol is esterified with a fatty acid, and the glycerin partial fatty acid ester includes glycerin monofatty acid ester and glycerin difatty acid ester. .

Examples of the fatty acid of the glycerin partial fatty acid ester include the carboxylic acids exemplified for R ⁵ in the above-described formula (P2). From the viewpoint of silica dispersibility, saturated fatty acids having 14 to 24 carbon atoms are preferable, and 16 to 22 saturated fatty acids are more preferred and stearic acid is most preferred. One type of fatty acid may be used alone, or two or more types may be used in combination, but when two or more types of fatty acids are used, one of them is preferably stearic acid.

  The glycerin partial fatty acid ester is preferably a glycerin monofatty acid ester from the viewpoint of dispersibility of silica. In the case of a mixture of glycerin monofatty acid ester and glycerin difatty acid ester, the content of glycerin monofatty acid ester is at least 50% by mass. It is preferable that

In the composition of the present invention, the ratio of the content of the specific cationic surfactant described above with respect to the content of the glycerin partial fatty acid ester (specific cationic surfactant / glycerin partial fatty acid ester) is 0.01 to 10, preferably 0.1 to 1.0, and more preferably 0.2 to 0.5.
Moreover, it is preferable that it is 0.1-10 mass parts with respect to 100 mass parts of diene rubbers mentioned above, and, as for content of glycerol partial fatty acid ester, it is more preferable that it is 1-5 mass parts. Moreover, it is preferable that content of the sum total of the specific cationic surfactant mentioned above and glycerol partial fatty acid ester is 0.2-10 mass parts with respect to 100 mass parts of diene rubbers mentioned above. A glycerol partial fatty acid ester may be used individually by 1 type, and may use 2 or more types together.

(Fatty acid metal salt)
The composition of the present invention preferably contains a fatty acid metal salt together with the specific cationic surfactant described above for the reason that the effects of the present invention are more excellent. Since the fatty acid metal salt improves the dispersibility of the specific cationic surfactant, as a result, the dispersibility of the silica is further increased, and the above-described effects of the present invention are further improved.

The fatty acid metal salt is a salt of a fatty acid and a metal.
Examples of the fatty acid of the fatty acid metal salt include carboxylic acids exemplified as R ⁵ in the formula (P2). From the viewpoint of dispersibility of silica, a saturated fatty acid having 8 to 24 carbon atoms is preferable, and a carbon atom having 10 to 22 carbon atoms is preferable. Saturated fatty acids are more preferred, saturated fatty acids having 16 to 22 carbon atoms are more preferred, and behenic acid is most preferred. A fatty acid may be used individually by 1 type, and may use 2 or more types together.
Examples of the metal of the fatty acid metal salt include alkali metals, alkaline earth metals, transition metals (groups 3 to 11 metals), aluminum, germanium, tin, antimony and the like. Among them, alkali metals (lithium, potassium, Sodium), alkaline earth metals (beryllium, magnesium, calcium, strontium, barium, etc.) and the like. From the viewpoint of silica dispersibility, alkali metals and alkaline earth metals are more preferred, and alkaline earth metals are further preferred. Magnesium is preferred and most preferred.
Specific examples of preferable fatty acid metal salts include potassium stearate, zinc stearate, magnesium stearate, magnesium oleate, magnesium palmitate, magnesium myristate, magnesium laurate, magnesium linoleate, and magnesium behenate.

  In the composition of the present invention, the ratio of the content of the specific cationic surfactant described above to the content of the fatty acid metal salt (specific cationic surfactant / fatty acid metal salt) is 0.01 to 10 by mass ratio. It is preferable that it is 0.1 to 1.0. Moreover, it is preferable that it is 0.1-10 mass parts with respect to 100 mass parts of diene rubbers mentioned above, and, as for content of a fatty-acid metal salt, it is more preferable that it is 0.5-5 mass parts. The total content of the specific cationic surfactant and the fatty acid metal salt is preferably 0.2 to 10 parts by mass with respect to 100 parts by mass of the diene rubber. A fatty acid metal salt may be used individually by 1 type, and may use 2 or more types together.

  The composition of the present invention preferably contains both the glycerin partial acid ester and the fatty acid metal salt together with the specific cationic surfactant described above for the reason that the effects of the present invention described above are further excellent.

(Other additives)
If necessary, the composition of the present invention may further contain an additive within a range not impairing its effects and purposes.
Examples of the additive include fillers other than silica (for example, carbon black), silane coupling agents other than the specific silane coupling agent described above, zinc oxide (zinc white), stearic acid, anti-aging agent, and processing aid. Various additives generally used in rubber compositions such as additives, process oils, aroma oils, liquid polymers, terpene resins, thermosetting resins, vulcanizing agents (for example, sulfur), and vulcanization accelerators. .

<Method for producing rubber composition for tire>
The production method of the composition of the present invention is not particularly limited, and specific examples thereof include, for example, kneading the above-described components using a known method and apparatus (for example, a Banbury mixer, a kneader, a roll, etc.). The method etc. are mentioned. When the composition of the present invention contains sulfur or a vulcanization accelerator, it is preferable to mix components other than sulfur and the vulcanization accelerator first, cool the mixture, and then mix the sulfur or vulcanization accelerator. .
The composition of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

[tire]
The tire (pneumatic tire) of the present invention is a tire manufactured using the above-described composition of the present invention. Especially, it is preferable that it is a tire which used the composition of this invention for the tread part (tire tread).
FIG. 1 shows a schematic partial sectional view of a tire representing an example of an embodiment of the tire of the present invention, but the tire of the present invention is not limited to the embodiment shown in FIG.

In FIG. 1, reference numeral 1 represents a bead portion, reference numeral 2 represents a sidewall portion, and reference numeral 3 represents a tire tread portion.
Further, a carcass layer 4 in which fiber cords are embedded is mounted between the pair of left and right bead portions 1, and the end of the carcass layer 4 extends from the inside of the tire to the outside around the bead core 5 and the bead filler 6. Wrapped and rolled up.
In the tire tread 3, a belt layer 7 is disposed over the circumference of the tire on the outside of the carcass layer 4.
Moreover, in the bead part 1, the rim cushion 8 is arrange | positioned in the part which touches a rim | limb.

  The tire of the present invention can be manufactured, for example, according to a conventionally known method. Moreover, as gas with which a tire is filled, inert gas, such as nitrogen, argon, helium other than the air which adjusted normal or oxygen partial pressure, can be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

[Preparation of rubber composition for tire]
The components shown in Table 1 below were blended in the proportions (parts by mass) shown in the same table.
Specifically, first, components other than sulfur and a vulcanization accelerator among the components shown in the same table were mixed for 5 minutes using a 1.7 liter closed Banbury mixer. The temperature at the time of discharge is as shown in “Mixed discharge temperature” in Table 1. The master batch was obtained by cooling to room temperature. Further, using the above Banbury mixer, sulfur and a vulcanization accelerator were mixed for 3 minutes with the obtained master batch and released at 110 ° C. to obtain a tire rubber composition.
In Table 1, for the amount of SBR, the upper value is the amount of SBR (oil-extended product) (unit: parts by mass), and the lower value is the net amount of SBR contained in SBR (unit: parts by mass). is there.

[Evaluation]
The following evaluation was performed about the obtained rubber composition for tires.

<Steering stability>
The obtained tire rubber composition (unvulcanized) was press vulcanized at 160 ° C. for 20 minutes in a mold (15 cm × 15 cm × 0.2 cm) to produce a vulcanized rubber sheet.
The produced vulcanized rubber sheet was cut into a dumbbell shape (dumbbell shape No. 3) having a thickness of 2 mm to obtain a test piece.
About the obtained test piece, 100% modulus (stress at the time of 100% elongation) [MPa] was measured according to JIS K6251: 2010. The results are shown in Table 1 (steering stability). The results were expressed as an index with the 100% modulus of Comparative Example 1 as 100. The larger the 100% modulus, the better the steering stability.

<Scorch resistance>
About the obtained tire rubber composition (unvulcanized), the scorch time was measured under the condition of a test temperature of 125 ° C. using an L-shaped rotor in accordance with JIS K6300-1: 2013. Table 1 shows the scorch time (scorch resistance). The results were expressed as an index with the scorch time of Comparative Example 1 as 100. The larger the index, the longer the scorch time and the better the scorch resistance.

<Vulcanization time>
About the obtained tire rubber composition (unvulcanized), the time to reach 90% vulcanization degree was measured at 160 ° C. based on JIS K6300. The results are shown in Table 1 (vulcanization time). The result was expressed as an index with the time of Comparative Example 1 as 100. The smaller the index, the shorter the vulcanization time and the better the workability.

The details of each component in Table 1 are as follows.
-SBR: E580 manufactured by Asahi Kasei Chemicals Corporation, oil-extended product (including 37.5 parts by mass of oil-extended oil with respect to 100 parts by mass of SBR. The net of SBR in SBR is 72.7% by mass)
-BR: Nipol BR 1220 manufactured by Nippon Zeon
Silica 1: Zeova 1205MP (CTAB: 200 m ² / g) manufactured by Solvay
Silica 2: Zeova 1165MP (CTAB: 160 m ² / g) manufactured by Solvay
-Carbon black: Seast 7HM manufactured by Tokai Carbon
Comparative silane coupling agent: Si69 (bis (3-triethoxysilylpropyl) tetrasulfide, manufactured by Evonik Degussa)
Silane coupling agent: 3-octanoylthiopropyltriethoxysilane (compound represented by the above formula (1). Here, R ¹ : ethoxy group, R ³ : trimethylene group, R ⁴ : heptyl group, m : 3.)
Cationic surfactant 1: structure shown below (wherein R ³ represents an acyl group derived from decanoic acid (capric acid))

Cationic surfactant 2: Structure shown below (wherein R ³ represents an acyl group derived from a mixed fatty acid (lauric acid / oleic acid = 2/1 (mass ratio))

Fatty acid metal salt: magnesium behenate (magnesium content 3.4% by mass)
-Glycerin partial fatty acid ester: Glycerin monostearate ester-Zinc flower: Zinc oxide 3 types of zinc oxide-Anti-aging agent: Santoflex 6PPD (manufactured by Solusia Europe)
・ Stearic acid: Industrial stearic acid N manufactured by Chiba Fatty Acid Co., Ltd.
・ Sulfur: Oil treatment sulfur manufactured by Hosoi Chemical Co., Ltd. ・ CBS: Noxeller CZ-G manufactured by Ouchi Shinsei Chemical Co.
-DPG: Ouchi Shinsei Chemical Industry Noxeller D

As can be seen from Table 1, each of Examples 1 to 8 in which the specific silane coupling agent and the specific cationic surfactant were used in combination exhibited excellent steering stability and scorch resistance.
From the comparison between Examples 1 to 3 and Examples 5 to 7, Examples 1 to 4, in which the specific cationic surfactant is a quaternary ammonium salt having an amide bond, showed better handling stability.
From the comparison of Examples 1 to 3 and the comparison of Examples 5 to 7, Examples 3 and 7 in which the silica content is 100 parts by mass or more with respect to 100 parts by mass of the diene rubber are more excellent in handling. Showed stability.
From the comparison with Example 1 and 2, and the comparison with Example 5 and 6, Example 2 and 6 whose content of a specific silane coupling agent is 8 mass parts or more with respect to 100 mass parts of diene rubbers. Showed better handling stability and scorch resistance, and excellent productivity.
From the comparison between Examples 3 and 4 and the comparison between Examples 7 and 8, Examples 3 and 7, in which the CTAB adsorption specific surface area of silica is 190 to 300 m ² / g, have superior steering stability. Indicated.

  On the other hand, in Comparative Examples 1 to 5 in which the specific silane coupling agent and the specific cationic surfactant were not used in combination, at least one of steering stability and scorch resistance was insufficient.

1 Bead part 2 Side wall part 3 Tire tread part 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Rim cushion

Claims (3)

Contains a diene rubber, silica, a silane coupling agent, and a cationic surfactant,
The silane coupling agent is a compound represented by the following formula (1):
The cationic surfactant is a quaternary ammonium salt having an amide bond or a carboxylic acid ester bond;
The silica content is 50 to 200 parts by mass with respect to 100 parts by mass of the diene rubber.
The content of the silane coupling agent is 4 to 15 parts by mass with respect to 100 parts by mass of the diene rubber,
The rubber composition for tires whose content of the said cationic surfactant is 0.05-10 mass parts with respect to 100 mass parts of said diene rubbers.
In formula (1), R ¹ represents an alkoxy group, R ² represents an alkyl group, R ³ represents an alkylene group, R ⁴ represents an alkyl group, and m represents an integer of 1 to 3. The rubber composition for tires according to claim 1 whose CTAB adsorption specific surface area of said silica is 190-300 m < ² > / g.   A tire manufactured using the rubber composition for tires according to claim 1.