JP7437271B2 - Rubber compositions, tires, and rubber additives - Google Patents

Description

The present invention relates to a rubber composition, a tire, and an additive for rubber.

BACKGROUND ART In recent years, regulations on exhaust gases including carbon dioxide have become stricter from the viewpoints of resource conservation, energy conservation, and environmental protection, and there is an increasing demand for automobiles to be more fuel efficient. The drive system and transmission system such as the engine make a large contribution to improving the fuel efficiency of automobiles, but the rolling resistance of tires also plays a large role, so it is important to improve not only the drive system and transmission system but also the rolling resistance of tires. is necessary.

As a method for improving the rolling resistance of tires, a method of blending a dihydrazide compound into a rubber composition is known (Patent Document 1).

However, when a dihydrazide compound is blended into a rubber composition, while the low heat generation property is improved, the viscosity (Mooney viscosity) of the rubber composition tends to increase, resulting in a problem that processability deteriorates.

Japanese Patent Application Publication No. 4-136048

In view of the above circumstances, an object of the present invention is to provide a rubber composition having excellent low heat generation properties and processability.

As a result of extensive research to solve the above problems, the present inventors have discovered that a rubber composition with excellent low heat build-up and processability can be obtained by adding a predetermined compound to a rubber component. The present inventor has conducted further research based on this knowledge and has completed the present invention.

〔式中、Ａは、環構造内に１～３個の窒素原子を有する六員の芳香族複素環を示し、さらに１又は複数の置換基を有していてもよい。前記置換基は、アミノ基、水酸基、アルキル基、アルコキシ基、ハロゲン原子、及びニトロ基から選ばれる。〕
項２．
前記六員の芳香族複素環がピリジン環である、項１に記載のゴム組成物。
項３．
さらに充填材を含む、項１又は２に記載のゴム組成物。
項４．
前記ゴム成分がジエン系ゴムである、項１～３のいずれかに記載のゴム組成物。
項５．
項１～４のいずれかに記載のゴム組成物を用いて作製されたタイヤ。
項６．
下記式（１）で表される化合物を含むゴム用添加剤。

〔式中、Ａは、環構造内に１～３個の窒素原子を有する六員の芳香族複素環を示し、さらに１又は複数の置換基を有していてもよい。前記置換基は、アミノ基、水酸基、アルキル基、アルコキシ基、ハロゲン原子、及びニトロ基から選ばれる。〕
項７．
低発熱化剤である、項６に記載の添加剤。 That is, the present invention provides the following rubber composition, tire, and rubber additive.
Item 1.
A rubber composition comprising a compound represented by the following formula (1) or a salt thereof, and a rubber component.

[In the formula, A represents a six-membered aromatic heterocycle having 1 to 3 nitrogen atoms in the ring structure, and may further have one or more substituents. The substituent is selected from an amino group, a hydroxyl group, an alkyl group, an alkoxy group, a halogen atom, and a nitro group. ]
Item 2.
Item 2. The rubber composition according to Item 1, wherein the six-membered aromatic heterocycle is a pyridine ring.
Item 3.
Item 3. The rubber composition according to Item 1 or 2, further comprising a filler.
Item 4.
Item 4. The rubber composition according to any one of Items 1 to 3, wherein the rubber component is a diene rubber.
Item 5.
Item 5. A tire produced using the rubber composition according to any one of Items 1 to 4.
Item 6.
A rubber additive containing a compound represented by the following formula (1).

[In the formula, A represents a six-membered aromatic heterocycle having 1 to 3 nitrogen atoms in the ring structure, and may further have one or more substituents. The substituent is selected from an amino group, a hydroxyl group, an alkyl group, an alkoxy group, a halogen atom, and a nitro group. ]
Section 7.
Item 6. The additive according to item 6, which is a low heat generation agent.

The rubber composition of the present invention has excellent low heat generation properties and excellent processability.

1. Rubber Composition The rubber composition of the present invention contains a compound represented by formula (1) described below or a salt thereof, and a rubber component. A rubber material obtained using the rubber composition has excellent low heat generation properties and processability, and can be suitably used for, for example, tires.

1.1. Compound Represented by Formula (1) The compound represented by Formula (1) is represented by the structural formula shown below.

In the above formula (1), A represents a six-membered aromatic heterocycle having 1 to 3 nitrogen atoms in the ring structure, and may further have one or more substituents. The substituent is selected from an amino group, a hydroxyl group, an alkyl group, an alkoxy group, a halogen atom, and a nitro group. When a plurality of these substituents exist on the six-membered aromatic heterocycle, these substituents may be the same or different from each other.

In A above, the "amino group" includes not only the amino group represented by -NH ₂ but also, for example, methylamino, ethylamino, n-propylamino, isopropylamino, n-butylamino, isobutylamino, s-butyl Linear or branched carbon atoms having 1 to 6 carbon atoms such as amino, t-butylamino, 1-ethylpropylamino, n-pentylamino, neopentylamino, n-hexylamino, isohexylamino, 3-methylpentylamino groups, etc. Chain-shaped monoalkylamino group; also includes substituted amino groups such as dialkylamino groups having two linear or branched alkyl groups having 1 to 6 carbon atoms, such as dimethylamino, ethylmethylamino, and diethylamino groups. defined as something.

Similarly, the "alkyl group" is not particularly limited, and includes, for example, linear, branched, or cyclic alkyl groups, and specifically includes, for example, methyl, ethyl, n-propyl, isopropyl, Straight-chain or branched alkyl groups having 1 to 4 carbon atoms such as n-butyl, isobutyl, s-butyl, t-butyl, and further 1-ethylpropyl, n-pentyl, isopentyl, neopentyl, n-hexyl , isohexyl, 3-methylpentyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, 5-propylnonyl, n-tridecyl, n-tetradecyl, n-pentadecyl, hexadecyl , heptadecyl, octadecyl, etc.; linear or branched alkyl groups having 5 to 18 carbon atoms; cyclic alkyl groups having 3 to 8 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, etc. can be mentioned.

The "alkoxy group" is not particularly limited, and includes, for example, a linear, branched or cyclic alkoxy group, and specifically includes, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy , t-butoxy, n-pentyloxy, neopentyloxy, linear or branched alkoxy groups of n-hexyloxy groups; cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, cyclo Examples include cyclic alkoxy groups such as octyloxy groups.

Examples of the "halogen atom" include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The "six-membered aromatic heterocycle" is not particularly limited as long as it has 1 to 3 nitrogen atoms in the ring structure. Specific examples include a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring. Among these, pyridine rings, pyrazine rings, pyrimidine rings, and pyridazine rings are preferred, and pyridine rings are more preferred. When a pyridine ring is employed, a rubber composition particularly excellent in low heat build-up and processability can be obtained.

A "six-membered aromatic heterocycle" has two carbonyl groups added as shown in formula (1), and may also have one or more substituents added, but a substituent other than the above two carbonyl groups Preferably, no groups are present.

More specifically, the compound represented by formula (1) includes pyridine-3,5-dicarbohydrazide, pyridine-2,6-dicarbohydrazide, pyridine-2,4-carbohydrazide, and pyridine-2 , 5-carbohydrazide. Among these, it is particularly preferable to employ pyridine-3,5-carbohydrazide.

The salt of the compound represented by formula (1) is not particularly limited and includes all kinds of salts. Examples of such salts include inorganic acid salts such as hydrochloride, sulfate, and nitrate; organic acid salts such as acetate and methanesulfonate.

Further, as a compound represented by the formula (1), for example, as shown in the following formula (2a), the nitrogen atom in the six-membered aromatic heterocycle is substituted with a hydrazide group etc. to make it quaternized, It may be a compound that forms a salt with an anionic halide such as chlorine, a hydroxide, or the like.

In the rubber composition of the present invention, the compound represented by formula (1) or its salt may contain only one type selected from the above-mentioned compounds and salts thereof, or may contain two or more types. They may be included in a mixture.

The compounding ratio of the compound represented by formula (1) or its salt is preferably 0.01 to 30 parts by mass, and preferably 0.05 to 5 parts by mass, per 100 parts by mass of the rubber component described below. is more preferable. By blending in this ratio, the effect of improving low heat build-up can be effectively obtained.

1.2. Rubber component The rubber component is not particularly limited, and includes, for example, natural rubber (NR), synthetic diene rubber, diene rubber such as a mixture of natural rubber and synthetic diene rubber, and other non-diene rubbers. can be used.

In addition to natural rubbers such as natural rubber latex, technically graded rubber (TSR), smoked sheet (RSS), gutta-percha, natural rubber derived from mori, natural rubber derived from guayule, and natural rubber derived from Russian dandelion, there are also epoxidized rubbers. Examples include modified natural rubber such as natural rubber, methacrylic acid-modified natural rubber, and styrene-modified natural rubber.

Examples of synthetic diene rubbers include styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), nitrile rubber (NBR), chloroprene rubber (CR), and ethylene-propylene-diene ternary rubber. Examples include polymer rubber (EPDM), styrene-isoprene-styrene triblock copolymer (SIS), styrene-butadiene-styrene triblock copolymer (SBS), and modified synthetic diene rubbers thereof. Examples of the modified synthetic diene rubber include diene rubbers obtained by modification methods such as main chain modification, one end modification, and both end modification. Here, examples of the modified functional group of the modified synthetic diene rubber include those containing one or more types of functional groups containing heteroatoms such as epoxy groups, amino groups, alkoxy groups, and hydroxyl groups. Further, there is no particular restriction on the cis/trans/vinyl ratio of the diene moiety, and any ratio can be suitably used. Further, the average molecular weight and molecular weight distribution of the diene rubber are not particularly limited, and an average molecular weight of 5 million to 3 million can be suitably used. There are no particular limitations on the method for producing synthetic diene rubber, and examples include those synthesized by emulsion polymerization, solution polymerization, radical polymerization, anionic polymerization, cationic polymerization, and the like.

As the non-diene rubber, a wide variety of known rubbers can be used.

The rubber component preferably contains a diene rubber, and in 100 parts by mass of the rubber component, the diene rubber preferably contains 50 parts by mass or more, more preferably 75 parts by mass or more, and 80 to 100 parts by mass. Parts by mass are particularly preferred.

Regarding the glass transition point of the diene rubber, a range of -70°C to -20°C is effective from the viewpoint of achieving both wear resistance and braking properties. In the rubber composition of the present invention, it is preferable that 50% by mass or more of the diene rubber is a diene rubber having a glass transition point in the range of -70°C to -20°C.

The rubber components can be used alone or in a mixture (blend) of two or more. Among these, preferable rubber components are natural rubber, IR, SBR, BR, or a mixture of two or more selected from these, and more preferably natural rubber, SBR, BR, or a mixture of two or more selected from these. . The blending ratio of these is not particularly limited, but it is preferable to blend SBR, BR, or a mixture thereof in a ratio of 50 to 100 parts by mass, and 75 to 100 parts by mass in 100 parts by mass of the rubber component. It is more preferable to mix them. When blending a mixture of SBR and BR, it is preferable that the total amount of SBR and BR is within the above range. Further, the SBR at this time is 50 to 100 parts by mass, and the BR is preferably in the range of 0 to 50 parts by mass.

1.3. Other Compounding Components In addition to the above-mentioned compounds and rubber components, the rubber composition of the present invention also includes fillers, compounding agents commonly used in the rubber industry, such as anti-aging agents, anti-ozonants, softeners, and processing agents. Auxiliary agents, waxes, resins, blowing agents, oils, stearic acid, zinc white (ZnO), vulcanization accelerators, vulcanization retarders, vulcanizing agents (sulfur), etc. may be used within the range that does not impair the purpose of the present invention. They can be appropriately selected and blended.

As the filler, it is possible to use a wide variety of known fillers used in the rubber industry. Specifically, carbon black and inorganic fillers can be exemplified, but of course the material is not limited to these.

The carbon black is not particularly limited, and examples thereof include commercially available carbon black, Carbon-Silica dual phase filler, and the like.

Specifically, carbon black includes, for example, high, medium or low structure SAF, ISAF, IISAF, N110, N134, N220, N234, N330, N339, N375, N550, HAF, FEF, GPF, SRF grade carbon. Black etc. can be mentioned. Among these, preferred carbon blacks are SAF, ISAF, IISAF, N134, N234, N330, N339, N375, HAF, or FEF grade carbon black.

The DBP absorption amount of carbon black is not particularly limited, and is preferably 60 to 200 cm ³ /100g, more preferably 70 to 180 cm ³ /100g, particularly preferably 80 to 160 cm ³ /100g.

Further, the nitrogen adsorption specific surface area (N2SA, measured according to JIS K 6217-2:2001) of carbon black is preferably 30 to 200 m ² /g, more preferably 40 to 180 m ² /g, particularly preferably It is 50 to 160 m ² /g.

The inorganic filler is not particularly limited as long as it is an inorganic compound commonly used in the rubber industry. Inorganic compounds that can be used include, for example, silica, alumina (Al ₂ O ₃ ) such as γ-alumina and α-alumina; alumina monohydrate (Al ₂ O ₃ .H ₂ O) such as boehmite and diaspore; gibbsite. , Bayerite, etc., aluminum hydroxide [Al(OH) ₃ ]; aluminum carbonate [Al ₂ (CO ₃ ) ₃ ], magnesium hydroxide [Mg(OH) ₂ ], magnesium oxide (MgO), magnesium carbonate (MgCO ₃ ), talc (3MgO・4SiO ₂・H ₂ O), attapulgite (5MgO・8SiO ₂・9H ₂ O), titanium white (TiO ₂ ), titanium black (TiO _2n-1 ), calcium oxide (CaO), hydroxide Calcium [Ca(OH) ₂ ], aluminum magnesium oxide (MgO・Al ₂ O ₃ ), clay (Al ₂ O ₃・2SiO ₂ ), kaolin (Al ₂ O ₃・2SiO ₂・2H ₂ O), pyrophyllite ( _{Al2O3.4SiO2.H2O )} , bentonite _{( Al2O3.4SiO2.2H2O} ), _aluminum silicate _{( Al2SiO5 , Al4.3SiO4.5H2O , etc. ) ,} Magnesium silicate ( _Mg2SiO4 , _MgSiO3 , etc.), calcium silicate ( _Ca2.SiO4 , etc. ₎ , aluminum calcium silicate ( _{Al2O3.CaO.2SiO2 , etc.} ), magnesium calcium silicate (CaMgSiO4 _{, etc.} ) ), calcium carbonate (CaCO ₃ ), zirconium oxide (ZrO ₂ ), zirconium hydroxide [ZrO(OH) ₂ ·nH ₂ O], zirconium carbonate [Zr(CO ₃ ) ₂ ], charge correction like various zeolites Examples include crystalline aluminosilicates containing hydrogen, alkali metals, or alkaline earth metals. The surface of these inorganic fillers may be organically treated in order to improve their affinity with the rubber component.

Among them, silica is preferable as the inorganic filler from the viewpoint of braking properties, and the BET specific surface area of silica is not particularly limited, and may be in the range of 40 to 350 m ² /g, for example. Silica having a BET specific surface area within this range has the advantage of being able to achieve both rubber reinforcing properties and dispersibility into the rubber component. The BET specific surface area is measured according to ISO 5794/1.

From this point of view, preferred silica is silica having a BET specific surface area of 50 to 350 m ² /g, more preferably silica having a BET specific surface area of 100 to 270 m ² /g, particularly preferably , silica with a BET specific surface area in the range of 110 to 270 m ² /g.

Commercial products of such silica include the product names "HD165MP" (BET specific surface area = 165 m ² /g), "HD115MP" (BET specific surface area = 115 m ² /g), manufactured by Quechen Silicon Chemical Co., Ltd. “HD200MP” (BET specific surface area = 200 m ² /g), “HD250MP” (BET specific surface area = 250 m ² /g), product name “Nip Seal AQ” manufactured by Tosoh Silica Co., Ltd. (BET specific surface area = 205 m ² /g) ), “Nip Seal KQ” (BET specific surface area = 240 m ² /g), and “Ultrasil VN3” (trade name, manufactured by Degussa) (BET specific surface area = 175 m ² /g).

The blending amount of the filler is preferably 20 to 120 parts by mass, more preferably 30 to 100 parts by mass, and even more preferably 40 to 90 parts by mass, per 100 parts by mass of the rubber component. preferable.

Among the fillers, carbon black or silica is preferred, and each may be used alone or in combination.

In addition, in a rubber composition containing the filler, silane coupling agents, titanate cups, etc. A ring agent, aluminate coupling agent, or zirconate coupling agent may be blended.

The silane coupling agent that can be used in combination with the filler is not particularly limited, and commercially available products can be suitably used. Examples of such silane coupling agents include sulfide-based, polysulfide-based, thioester-based, thiol-based, olefin-based, epoxy-based, amino-based, and alkyl-based silane coupling agents.

Examples of sulfide-based silane coupling agents include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(3-methyldimethoxysilylpropyl)tetrasulfide, and bis(3-trimethoxysilylpropyl)tetrasulfide. 2-triethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(3-methyldimethoxysilylpropyl)disulfide, bis(2-triethoxysilyl) ethyl)disulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-trimethoxysilylpropyl)trisulfide, bis(3-methyldimethoxysilylpropyl)trisulfide, bis(2-triethoxysilylethyl)trisulfide Sulfide, bis(3-monoethoxydimethylsilylpropyl)tetrasulfide, bis(3-monoethoxydimethylsilylpropyl)trisulfide, bis(3-monoethoxydimethylsilylpropyl)disulfide, bis(3-monomethoxydimethylsilylpropyl) Tetrasulfide, bis(3-monomethoxydimethylsilylpropyl)trisulfide, bis(3-monomethoxydimethylsilylpropyl)disulfide, bis(2-monoethoxydimethylsilylethyl)tetrasulfide, bis(2-monoethoxydimethylsilylethyl) ) trisulfide, bis(2-monoethoxydimethylsilylethyl) disulfide, and the like. Among these, bis(3-triethoxysilylpropyl)tetrasulfide is particularly preferred.

Examples of thioester-based silane coupling agents include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, and 3-lauroylthiopropyltriethoxysilane. , 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3-hexanoylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, 2-octanoylthioethyltrimethoxysilane, 2 -decanoylthioethyltrimethoxysilane, 2-lauroylthioethyltrimethoxysilane and the like.

Examples of thiol-based silane coupling agents include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-[ethoxybis(3,6,9,12,15 -pentaoxaoctacosan-1-yloxy)silyl]-1-propanethiol and the like.

Examples of olefin-based silane coupling agents include dimethoxymethylvinylsilane, vinyltrimethoxysilane, dimethylethoxyvinylsilane, diethoxymethylvinylsilane, triethoxyvinylsilane, vinyltris(2-methoxyethoxy)silane, allyltrimethoxysilane, and allyltrimethoxysilane. Ethoxysilane, p-styryltrimethoxysilane, 3-(methoxydimethoxydimethylsilyl)propyl acrylate, 3-(trimethoxysilyl)propyl acrylate, 3-[dimethoxy(methyl)silyl]propyl methacrylate, 3-(trimethoxysilyl) Examples include propyl methacrylate, 3-[dimethoxy(methyl)silyl]propyl methacrylate, 3-(triethoxysilyl)propyl methacrylate, and 3-[tris(trimethylsiloxy)silyl]propyl methacrylate.

Examples of epoxy-based silane coupling agents include 3-glycidyloxypropyl(dimethoxy)methylsilane, 3-glycidyloxypropyltrimethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, and triethoxy(3-glycidyloxypropyl)silane. , 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and the like. Among these, 3-glycidyloxypropyltrimethoxysilane is preferred.

Examples of amino-based silane coupling agents include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyl Trimethoxysilane, 3-aminopropyltriethoxysilane, 3-ethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)- Examples include 2-aminoethyl-3-aminopropyltrimethoxysilane. Among these, 3-aminopropyltriethoxysilane is preferred.

Examples of alkyl-based silane coupling agents include methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, and isobutyltriethoxysilane. Examples include silane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane. Among these, methyltriethoxysilane is preferred.

Among these silane coupling agents, bis(3-triethoxysilylpropyl)tetrasulfide can be particularly preferably used.

The titanate coupling agent that can be used in combination with the filler is not particularly limited, and commercially available products can be suitably used. Examples of such titanate coupling agents include alkoxide-based, chelate-based, and acylate-based titanate coupling agents.

Examples of the alkoxide-based titanate coupling agent include tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetraoctyl titanate, tetratert-butyl titanate, tetrastearyl titanate, and the like. Among these, tetraisopropyl titanate is preferred.

Examples of chelate-based titanate coupling agents include titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethyl acetoacetate, titanium dodecylbenzenesulfonic acid compounds, titanium phosphate compounds, titanium octylene glycolate, and titanium ethyl acetoacetate. , titanium lactate ammonium salt, titanium lactate, titanium ethanolaminate, titanium octylene glycolate, titanium aminoethylaminoethanolate, and the like. Among these, titanium acetylacetonate is preferred.

Examples of the acylate-based titanate coupling agent include titanium isostearate.

The aluminate coupling agent that can be used in combination with the filler is not particularly limited, and commercially available products can be suitably used. Examples of such aluminate coupling agents include 9-octadecenylacetoacetate aluminum diisopropylate, aluminum secondary butoxide, aluminum trisacetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum trisethylacetoacetate, etc. can be mentioned. Among these, 9-octadecenyl acetoacetate aluminum diisopropylate is preferred.

The zirconate coupling agent that can be used in combination with the filler is not particularly limited, and commercially available products can be suitably used. Examples of such zirconate coupling agents include alkoxide-based, chelate-based, and acylate-based zirconate coupling agents.

Examples of the alkoxide-based zirconium coupling agent include normal propyl zirconate and normal butyl zirconate. Among these, normal butyl zirconate is preferred.

Examples of chelate-based zirconate coupling agents include zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium ethyl acetoacetate, and zirconium lactate ammonium salt. Among these, zirconium tetraacetylacetonate is preferred.

Examples of the acylate-based zirconate coupling agent include zirconium stearate and zirconium octylate. Among these, zirconium stearate is preferred.

In the present invention, one type of silane coupling agent, titanate coupling agent, aluminate coupling agent, and zirconate coupling agent may be used alone, or two or more types may be used in combination.

The amount of the silane coupling agent blended is preferably 0.1 to 20 parts by weight, more preferably 3 to 15 parts by weight, based on 100 parts by weight of the filler. When it is 0.1 parts by mass or more, the effect of improving the tear strength of the rubber composition can be more suitably expressed, and when it is 20 parts by mass or less, the cost of the rubber composition is reduced and economical efficiency is improved. Because it does.

2. Tire By manufacturing a tire using the above-described rubber composition of the present invention, a tire with excellent low heat build-up can be obtained.

In the tire of the present invention, the rubber composition is used particularly for at least one member selected from the tread section, sidewall section, bead area section, belt section, carcass section, and shoulder section.

Among these, one of the most preferred embodiments is to form the tire tread portion of a pneumatic tire using the rubber composition.

The tread is the part of the tire that has a tread pattern and is in direct contact with the road surface, and protects the carcass part and prevents wear and damage. The base tread is the base tread placed inside the tread.

The sidewall section is, for example, a section of a pneumatic radial tire from the lower side of the shoulder section to the bead section, which protects the carcass section and is the section that bends the most during running.

The bead area is the part that fixes both ends of the carcass cord and at the same time fixes the tire to the rim. A bead is a structure made of bundles of high carbon steel.

The belt portion is a reinforcing band stretched in the circumferential direction between the radial-structured tread and the carcass. The carcass is strongly tightened like a hoop in a tub to increase the rigidity of the tread.

The carcass is a part of the cord layer that forms the frame of the tire, and plays a role in withstanding the load, impact, and air pressure that the tire receives.

The shoulder part is the shoulder part of the tire and serves to protect the carcass part.

The tire of the present invention can be manufactured according to methods hitherto known in the field of tires. Further, as the gas to be filled in the tire, normal air or air with adjusted oxygen partial pressure; inert gas such as nitrogen, argon, helium, etc. can be used.

3. Additive for Rubber By using the compound represented by the above formula (1) or a salt thereof as an additive for rubber, it is possible to impart excellent low heat generation properties to the rubber material formed. Such rubber additives may be composed only of the compound or its salt itself, that is, the compound represented by formula (1) or its salt, or may contain other additives within the range that does not impede its effect. It may also contain ingredients. As other components, it is possible to use a wide range of known oils, resins, stearic acid, zinc white (ZnO), calcium carbonate, silica, and the like.

4. Low heat generation agent As described above, the rubber additive of the present invention can impart excellent low heat generation properties to rubber materials, and can be suitably used as a low heat generation agent.

5. Manufacturing method of rubber composition There is no particular limitation on the manufacturing method of the rubber composition of the present invention, and for example, the above-mentioned rubber component, the compound represented by formula (1) or its salt, and other components as necessary. can be obtained by mixing. Moreover, the compound represented by formula (1) or its salt may also be produced by a known method.

The method for mixing described above is not particularly limited, and a wide variety of known methods can be employed. Specifically, a method can be mentioned in which the above-described rubber component, the compound represented by formula (1) or its salt, and other components as necessary are kneaded using a kneader or the like.

Although the embodiments of the present invention have been described above, the present invention is not limited to these examples at all, and it goes without saying that the present invention can be implemented in various forms without departing from the gist of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail based on Examples, but the present invention is not limited thereto.

Production Example 1: Production of 3,5-pyridinecarboxylic acid dihydrazide (compound a) To a solution of 15.9 g of diethyl 3,5-pyridinedicarboxylate added to 70 mL of methanol, 8.66 g of hydrazine monohydrate was added. , and refluxed for 24 hours. The reaction solution was cooled, the precipitated solid was collected by filtration, and the obtained solid was washed with methanol and dried to obtain 13.9 g (yield: 100.0%) of the target product.
^1H -NMR (400MHz, DMSO-d ₆ , δppm):
4.6 (br-s, 4H), 8.5 (t, 1H), 9.0 (d, 2H), 10.0 (br-s, 2H)
Melting point: 234℃

Production Example 2: Production of pyridine-2,6-carbohydrazide (compound b) To a solution of 12.6 g of dimethyl 2,6-pyridinedicarboxylate added to 65 mL of methanol, 8.08 g of hydrazine monohydrate was added. Refluxed for an hour. The reaction solution was cooled, the precipitated solid was filtered, and the obtained solid was washed with methanol and dried to obtain 12.4 g (yield: 98.8%) of the target product.
^1H -NMR (400MHz, DMSO-d ₆ , δppm):
4.6 (br-s, 4H), 8.1 (m, 3H), 10.6 (br-s, 2H)
Melting point: 287℃

Production Example 3: Production of pyridine-2,4-carbohydrazide (compound c) A solution of 25.4 g of 2,4-pyridinedicarboxylic acid added to 150 mL of methanol was cooled, and 52.5 g of thionyl chloride was added dropwise. Refluxed for an hour. After cooling the reaction solution and distilling off the solvent, the precipitated solid was filtered, washed with hexane and diethyl ether, and dried to obtain dimethyl 2,4-pyridinedicarboxylate. 120 mL of methanol was added to this dimethyl 2,4-pyridinedicarboxylate, 15.4 g of hydrazine monohydrate was added, and the mixture was refluxed for 24 hours. The reaction solution was cooled, the precipitated solid was filtered, and the obtained solid was washed with methanol and dried to obtain 23.0 g (yield: 97.0%) of the desired product.
^1H -NMR (400MHz, DMSO-d ₆ , δppm):
4.6 (br-s, 2H), 4.7 (br-s, 2H), 7.9 (m, 1H), 8.3 (m, 1H), 8.7 (m, 1H), 10 .0 (br-s, 1H), 10.3 (br-s, 1H)
Melting point: 299℃

Production Example 4: Production of pyridine-2,5-carbohydrazide (compound d) To a solution of 6.50 g of dimethyl 2,5-pyridinedicarboxylate added to 30 mL of methanol, 4.73 g of hydrazine monohydrate was added. Refluxed for an hour. This reaction solution was cooled, the precipitated solid was filtered, the obtained solid was washed with methanol, and then dried to obtain 5.64 g (yield: 99.2%) of the target product.
^1H -NMR (400MHz, DMSO-d ₆ , δppm):
4.6 (br-s, 4H), 8.0 (m, 1H), 8.3 (m, 1H), 9.0 (m, 1H), 10.0 (br-s, 1H), 10 .1 (br-s, 1H)
Melting point: 286℃

Examples 1 to 4, Comparative Example 1, and Reference Example 1: Production of Rubber Composition The components listed in step (I) of Table 1 below were mixed in the proportions (parts by mass) and kneaded using a Banbury mixer. After curing until the temperature of the mixture becomes 80°C or less, add each component listed in step (II) of Table 1 in the proportion (parts by mass) and adjust so that the maximum temperature of the mixture becomes 110°C or less. While kneading, an unvulcanized rubber composition was produced. Each rubber was obtained by heating the unvulcanized rubber composition obtained here at 150° C. for 30 minutes using a vulcanization press.

Low heat build-up (Tan δ value index) test For the rubber compositions of each example and comparative example, the Tan δ value was measured at a temperature of 40°C, a dynamic strain of 5%, and a frequency of 15 Hz using a viscoelasticity measuring device (manufactured by Metravib). did. For comparison, a rubber composition (Reference Example 1) was prepared using the same formulation and the same manufacturing method as in each example, except that no compound was added, and the Tan δ value was expressed as an index with 100, and based on the following formula: The low pyrogenicity index was calculated. Note that the smaller the value of the low heat generation index, the lower the heat generation and the smaller the hysteresis loss.
Formula: Low heat generation index = (Tan δ value of the rubber compositions of Examples 1 to 4 and Comparative Example 1) x 100/(Tan δ value of Reference Example 1)

Processability (Mooney viscosity index) test Measured according to JIS K6300-1 (how to determine viscosity and scorch time using a Mooney viscometer; ML1+4,100°C). For comparison, a rubber composition (Reference Example 1) was prepared using the same formulation and the same manufacturing method as each Example except that no compound was added, and the Mooney viscosity value was expressed as an index with 100, and the formula was expressed by the following formula. The processability index was calculated based on this. Note that the smaller the value of the workability index, the better the workability.
Formula: Processability index = (Mooney viscosity value of the rubber compositions of Examples 1 to 4 and Comparative Example 1) x 100/(Mooney viscosity value of Reference Example 1)

※１：天然ゴム；ＧＵＡＮＧＫＥＮ ＲＵＢＢＥＲ社製、ＴＳＲ－２０
※２：製造例１で製造したピリジン－３，５－カルボヒドラジド
※３：製造例２で製造したピリジン－２，６－カルボヒドラジド
※４：製造例３で製造したピリジン－２，４－カルボヒドラジド
※５：製造例４で製造したピリジン－２，５－カルボヒドラジド
※６：イソフタル酸ジヒドラジド；大塚化学社製
※７：カーボンブラック；Ｃａｂｏｔ社製、Ｎ２３４
※８：老化防止剤（Ｎ－フェニル－Ｎ'－（１,３－ジメチルブチル）－ｐ－フェニレンジアミン）；Ｋｅｍａｉ Ｃｈｅｍｉｃａｌ Ｃｏ．，Ｌｔｄ社製
※９：ワックス；Ｒｈｅｉｎ Ｃｈｅｍｉｅ Ｒｈｅｉｎａｕ社製、Ａｎｔｉｌｕｘ １１１
※１０：酸化亜鉛；Ｄａｌｉａｎ Ｚｉｎｃ Ｏｘｉｄｅ Ｃｏ．，Ｌｔｄ社製
※１１：ステアリン酸；Ｓｉｃｈｕａｎ Ｔｉａｎｙｕ Ｇｒｅａｓｅ社製
※１２：加硫促進剤；Ｎ－(ｔｅｒｔ－ブチル)－２－ベンゾチアゾールスルフェンアミド；三新化学工業株式会社製、サンセラーＮＳ－Ｇ
※１３：硫黄；Ｓｈａｎｇｈａｉ Ｊｉｎｇｈａｉ Ｃｈｅｍｉｃａｌ Ｃｏ．，Ｌｔｄ社製

*1: Natural rubber; manufactured by GUANGKEN RUBBER, TSR-20
*2: Pyridine-3,5-carbohydrazide produced in Production Example 1 *3: Pyridine-2,6-carbohydrazide produced in Production Example 2 *4: Pyridine-2,4-carbohydrazide produced in Production Example 3 Hydrazide *5: Pyridine-2,5-carbohydrazide produced in Production Example 4 *6: Isophthalic acid dihydrazide; manufactured by Otsuka Chemical *7: Carbon black; manufactured by Cabot, N234
*8: Anti-aging agent (N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine); Kemai Chemical Co. , Ltd *9: Wax; Rhein Chemie Rheinau, Antilux 111
*10: Zinc oxide; Dalian Zinc Oxide Co. , Ltd *11: Stearic acid; manufactured by Sichuan Tianyu Grease *12: Vulcanization accelerator; N-(tert-butyl)-2-benzothiazolesulfenamide; manufactured by Sanshin Chemical Industry Co., Ltd., Suncella NS- G
*13: Sulfur; Shanghai Jinghai Chemical Co. , Ltd.

Since the rubber composition of the present invention contains the compound represented by formula (1) or a salt thereof and a rubber component, it has sufficient processability and also has excellent low heat generation property. It can be suitably used as a tire material.

Claims (7)

Contains a compound represented by the following formula (1) or a salt thereof, and a rubber component,
A rubber composition in which the compound or its salt is blended in an amount of 0.01 to 30 parts by mass based on 100 parts by mass of the rubber component.

[In the formula, A represents a six-membered aromatic heterocycle having 1 to 3 nitrogen atoms in the ring structure, and may further have one or more substituents. The substituent is selected from an amino group, a hydroxyl group, an alkyl group, an alkoxy group, a halogen atom, and a nitro group. ] The rubber composition according to claim 1, wherein the six-membered aromatic heterocycle is a pyridine ring. The rubber composition according to claim 1 or 2, further comprising a filler. The rubber composition according to any one of claims 1 to 3, wherein the rubber component is a diene rubber. A tire produced using the rubber composition according to any one of claims 1 to 4. A rubber additive containing a compound represented by the following formula (1) or a salt thereof .

[In the formula, A represents a six-membered aromatic heterocycle having 1 to 3 nitrogen atoms in the ring structure, and may further have one or more substituents. The substituent is selected from an amino group, a hydroxyl group, an alkyl group, an alkoxy group, a halogen atom, and a nitro group. ] The additive according to claim 6, which is a low heat generation agent.