JP7259526B2 - Tire rubber composition and tire - Google Patents

Description

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

2. Description of the Related Art Conventionally, it has been attempted to reduce the rolling resistance of a tire by making the tread rubber less heat-generating, thereby reducing the fuel consumption of a vehicle.

As a method of satisfying the low heat build-up of the rubber composition, a method of using a low-reinforcing filler, a method of reducing the content of the reinforcing filler, and the like are known. However, fuel efficiency improvement by such a filler has a problem that the reinforcing property of the rubber composition is deteriorated, so that the breaking property is lowered. Have difficulty.

For example, Patent Document 1 discloses a rubber composition containing a hydrazide compound, but there is room for improvement in terms of improving the overall performance of processability, fuel economy, and breaking properties.

JP 2019-1864 A

An object of the present invention is to solve the above problems and to provide a rubber composition and a tire with improved overall performance of workability, fuel economy and breaking properties.

As a result of intensive studies, the present inventors have found that the total content of carbon black and silica is 30 per 100 parts by mass of the rubber component, which contains an isoprene-based rubber, a peptization accelerator, a hydrazide compound, and saturated fatty acid glycerides. It has been found that the use of a rubber composition for tires having an amount of up to 120 parts by mass improves the overall performance of processability, fuel economy, and breaking properties.
That is, the present invention contains an isoprene-based rubber, a peptizer, a hydrazide compound, and saturated fatty acid glycerides, and the total content of carbon black and silica is 30 to 120 parts by mass with respect to 100 parts by mass of the rubber component. It relates to a rubber composition for tires.

In the rubber composition, the content of the hydrazide compound is preferably 0.3 to 1.2 parts by mass with respect to 100 parts by mass of isoprene-based rubber.

The rubber composition preferably contains carbon black and silica.

The rubber composition is preferably a tread rubber composition.

The invention also relates to a tire having a tread using the rubber composition.

According to the present invention, an isoprene-based rubber, a peptizer, a hydrazide compound, and saturated fatty acid glycerides are included, and the total content of carbon black and silica is 30 to 120 parts by mass with respect to 100 parts by mass of the rubber component. Since it is a rubber composition for tires, the overall performance of workability, fuel efficiency and breaking properties is improved.

The rubber composition for tires of the present invention contains an isoprene-based rubber, a peptizer, a hydrazide compound, and saturated fatty acid glycerides, and the total content of carbon black and silica is 30 per 100 parts by mass of the rubber component. ~120 parts by mass. This improves the overall performance of workability, fuel economy, and breaking properties.

Although the reason why such effects are obtained is not necessarily clear, it is speculated as follows.
In a rubber composition containing an isoprene rubber and a filler (especially carbon black), the use of a peptization accelerator can improve processability, but tends to deteriorate fuel economy. By using a hydrazide compound together, deterioration of fuel efficiency can be suppressed.
On the other hand, the combined use of saturated fatty acid glycerides with fillers (especially carbon black, silica, especially silica) improves the dispersibility of the fillers (especially carbon black, silica, especially silica).
Then, in the rubber composition containing isoprene rubber, by blending a peptization accelerator, a hydrazide compound, and a saturated fatty acid glyceride together with a filler, good processability is maintained by blending the peptization accelerator. In addition, the dispersibility of the filler is improved, and the heat build-up of the rubber itself is suppressed, thereby improving the overall performance of workability, fuel economy, and breaking properties.
In particular, by using a hydrazide compound and a saturated fatty acid glyceride in combination in a rubber composition containing an isoprene rubber, it is possible to synergistically improve the overall performance of processability, fuel efficiency, and fracture characteristics, resulting in good processability. Overall performance of durability, low fuel consumption, and breaking properties can be obtained.

The rubber composition contains an isoprene-based rubber.
The isoprene rubber includes natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, modified IR, and the like. As NR, for example, those commonly used in the tire industry, such as SIR20, RSS#3, and TSR20, can be used. The IR is not particularly limited, and for example IR2200 or the like commonly used in the tire industry can be used. 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. Examples of modified IR 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.

The content of isoprene-based rubber in 100% by mass of the rubber component is preferably 10% by mass or more, more preferably 20% by mass or more, and still more preferably 30% by mass or more. % by mass or less, more preferably 85% by mass or less. Within the above range, the effect tends to be obtained more favorably.

Examples of rubber components that can be used in the rubber composition other than isoprene-based rubbers include diene-based rubbers other than isoprene-based rubbers.
Diene rubbers include butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene-butadiene rubber (SIBR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile-butadiene rubber (NBR). be done. In addition, rubber components other than those described above include butyl-based rubbers, fluororubbers, and the like. These may be used alone or in combination of two or more. Among them, SBR and BR are preferred, and BR is more preferred.

Here, the rubber component preferably has a weight average molecular weight (Mw) of 200,000 or more, more preferably 350,000 or more. Although the upper limit of Mw is not particularly limited, it is preferably 4,000,000 or less, more preferably 3,000,000 or less.
In the present specification, Mw and number average molecular weight (Mn) are measured by gel permeation chromatography (GPC) (GPC-8000 series manufactured by Tosoh Corporation, detector: differential refractometer, column: manufactured by Tosoh Corporation. TSKGEL SUPERMULTIPORE HZ-M) can be obtained by standard polystyrene conversion.

When a diene rubber is contained, the content of the diene rubber in 100% by mass of the rubber component is preferably 20% by mass or more, more preferably 50% by mass or more, still more preferably 70% by mass or more, and particularly preferably 80% by mass. It is at least 90% by mass, most preferably at least 90% by mass, and may be 100% by mass. Within the above range, the effect tends to be obtained more favorably.
The content of diene rubber also includes the content of isoprene rubber.

The rubber component may be non-modified diene rubber or modified diene rubber.
The modified diene rubber may be any diene rubber having a functional group that interacts with a filler such as silica. Terminal modified diene rubber modified with (terminal modified diene rubber having the above functional group at the end), main chain modified diene rubber having the above functional group on the main chain, and the above functional group on the main chain and terminal main chain end-modified diene rubber (for example, main chain end-modified diene rubber having the above functional group in the main chain and at least one end modified with the above modifier), or two or more in the molecule A terminal-modified diene rubber modified (coupled) with a polyfunctional compound having an epoxy group and introduced with a hydroxyl group or an epoxy group is exemplified.

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, an 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), an alkoxy group (preferably an alkoxy group having 1 to 6 carbon atoms), an alkoxysilyl group ( An alkoxysilyl group having 1 to 6 carbon atoms is preferred.

BR is not particularly limited, and for example, high cis BR having a high cis content, BR containing syndiotactic polybutadiene crystals, BR synthesized using a rare earth catalyst (rare earth BR), and the like can be used. These may be used alone or in combination of two or more. Among them, high-cis BR having a cis content of 90% by mass or more is preferable because it improves wear resistance performance. The cis content can be measured by infrared absorption spectrometry.

BR may be non-denatured BR or denatured BR. Examples of modified BR include modified BR into which functional groups similar to those of modified diene rubber have been introduced.

As BR, for example, products of Ube Industries, Ltd., JSR Corporation, Asahi Kasei Co., Ltd., Nippon Zeon Co., Ltd., etc. can be used.

When BR is contained, the content of BR in 100% by mass of the rubber component is preferably 5% by mass or more, more preferably 15% by mass or more, and preferably 80% by mass or less, more preferably 65% by mass or less. is. 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% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, particularly preferably 20% by mass or more, most preferably 25% by mass or more, and most preferably 30% by mass or more. It is at least 35% by mass, more preferably at least 35% by mass. Also, the styrene content is preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 45% 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 H ¹ -NMR measurement.

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 modified SBR into which functional groups similar to those of modified diene rubber have been introduced.

The rubber composition contains a peptizer.
In the present specification, the peptization accelerator means an agent added in the rubber mastication process, usually for the purpose of shortening the mastication time, and is also called a peptizer or a peptizer.

As the peptizer, for example, aromatic mercaptan-based, aromatic disulfide-based, and aromatic mercaptan metal salt-based agents that have been used in conventional rubber compositions for tires can be suitably used. These may be used alone or in combination of two or more. Among them, the aromatic disulfide type and the aromatic mercaptan metal salt type are preferable, and the aromatic disulfide type is more preferable.

Examples of aromatic mercaptans include xylene thiophenol, pentachlorothiophenol, β-naphthylmercaptan, pt-butylthiophenol, t-butyl-o-thiocresol, o-benzamidothiophenol and the like. Examples of aromatic disulfides include o,o'-dibenzamide diphenyl disulfide and bis(2,4-dimethylphenyl) disulfide. Examples of the aromatic mercaptan metal salt include the above aromatic mercaptan metal salts (zinc salt, etc.). Among them, o,o'-dibenzamide diphenyl disulfide is preferred, and a mixture of o,o'-dibenzamide diphenyl disulfide and stearic acid is more preferred.

Commercially available peptizers are not particularly limited, but examples include Noctizer SS (o,o'-dibenzamidodiphenyl disulfide), SZ (zinc of o-benzamidothiophenol, manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.). salt), SD (a mixture of o,o'-dibenzamide diphenyl disulfide and an additive such as stearic acid), SM, SX, SK, SZK and the like.

The melting point of the peptizer is preferably 30° C. or higher, more preferably 40° C. or higher, still more preferably 50° C. or higher, and the melting point is preferably 160° C. or lower, more preferably 150° C. or lower, and still more preferably 100° C. or lower, particularly preferably 70° C. or lower. Within the above range, the effect tends to be obtained more favorably.
In this specification, the melting point of the peptizer is a value measured according to the visual inspection method of JIS-K6220.

The content of the peptizing accelerator is not particularly limited as long as the processability can be ensured. parts or more, more preferably 0.05 parts by mass or more, particularly preferably 0.1 parts by mass or more, and the content is preferably 0.5 parts by mass or less, more preferably 0.3 parts by mass or less . Within the above range, the effect tends to be obtained more favorably.

The rubber composition contains a hydrazide compound.
As used herein, a hydrazide compound means a compound having a hydrazide group (—CONHNH ₂ ). Although the number of hydrazide groups possessed by the hydrazide compound is not particularly limited, the hydrazide compound is preferably a hydrazide compound having one or two hydrazide groups in the molecule, and a dihydrazide compound having two hydrazide groups in the molecule. It is more preferable to have

The number of carbon atoms in the hydrazide compound is preferably 2 or more, more preferably 3 or more, still more preferably 5 or more, preferably 50 or less, more preferably 35 or less, still more preferably 15 or less, and particularly preferably 8 or less. . Within the above range, there is a tendency that good affinity for rubber can be obtained, and more favorable effects can be obtained.

Examples of hydrazide compounds include adipic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, azelaic acid dihydrazide, succinic acid dihydrazide, eicosanedioic acid dihydrazide, 7,11-octadecadiene-1,18-dicarbohydrazide, and salicylic acid hydrazide. , 4-methylbenzoic acid hydrazide, 3-hydroxy-N'-(1,3-dimethylbutylidene)-2-naphthoic acid hydrazide, sebacic acid dihydrazide, dodecanedioic acid dihydrazide, propionic acid hydrazide, stearic acid hydrazide, palmitic acid Hydrazide, lauric hydrazide (dodecanoic hydrazide), butyric hydrazide, pentanoic hydrazide, hexanoic hydrazide, heptanoic hydrazide, octanoic hydrazide, nonanoic hydrazide, decanoic hydrazide, undecanoic hydrazide, isonicotinic hydrazide, carbodihydrazide , 1,3-bis(hydrazinocarboethyl)-5-isopropylhydantoin, icosanoic acid dihydrazide, anthranilic acid hydrazide, 4-hydroxybenzoic acid hydrazide, 2-hydroxy-3-naphthoic acid hydrazide, oxalic acid hydrazide, anthraniloyl hydrazine, 4-hydroxybenzoic acid hydrazide and the like. These may be used alone or in combination of two or more.

（式（１）及び（２）中、Ｒは分岐若しくは非分岐の炭素数１～３０（炭素数は、好ましくは２以上であり、好ましくは１５以下、より好ましくは１０以下、更に好ましくは７以下）の２価の炭化水素基を表す。） The hydrazide compound is preferably a compound represented by the following formula (1) or (2), more preferably a compound represented by the following formula (1).

(In the formulas (1) and (2), R is a branched or unbranched carbon number of 1 to 30 (the number of carbon atoms is preferably 2 or more, preferably 15 or less, more preferably 10 or less, still more preferably 7 below) represents a divalent hydrocarbon group.)

Examples of the hydrocarbon group include a branched or unbranched alkylene group having 1 to 30 carbon atoms, a branched or unbranched alkenylene group having 2 to 30 carbon atoms, and a branched or unbranched alkynylene group having 2 to 30 carbon atoms. , an arylene group having 6 to 30 carbon atoms, and the like. Among them, a branched or unbranched alkylene group having 1 to 30 carbon atoms and an arylene group having 6 to 30 carbon atoms are preferable, and a branched or unbranched alkylene group having 1 to 30 carbon atoms is more preferable.

The branched or unbranched alkylene group having 1 to 30 carbon atoms (the number of carbon atoms is preferably 2 or more, preferably 15 or less, more preferably 10 or less, and still more preferably 7 or less) for R includes, for example, methylene group, ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group , an octadecylene group, and the like.

The branched or unbranched alkenylene group having 2 to 30 carbon atoms (the number of carbon atoms is preferably 2 or more, preferably 15 or less, more preferably 10 or less, and still more preferably 6 or less) for R includes, for example, vinylene group, 1-propenylene group, 2-propenylene group, 1-butenylene group, 2-butenylene group, 1-pentenylene group, 2-pentenylene group, 1-hexenylene group, 2-hexenylene group, 1-octenylene group and the like. .

The branched or unbranched alkynylene group having 2 to 30 carbon atoms (the number of carbon atoms is preferably 2 or more, preferably 15 or less, more preferably 10 or less, and still more preferably 6 or less) for R includes, for example, ethynylene group, propynylene group, butynylene group, pentynylene group, hexynylene group, heptynylene group, octinylene group, nonynylene group, decinylene group, undecynylene group, dodecynylene group and the like.

Examples of the arylene group of R having 6 to 30 carbon atoms (the number of carbon atoms is preferably 15 or less, more preferably 10 or less, and still more preferably 8 or less) include a phenylene group, a tolylene group, a xylylene group, a naphthylene group, and the like. can give.

As the hydrazide compound, products of Otsuka Chemical Co., Ltd., Japan Finechem Co., Ltd., Tokyo Kasei Kogyo Co., Ltd., etc. can be used.

The content of the hydrazide compound is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, still more preferably 250 parts by mass or more, particularly preferably 350 parts by mass or more, and most preferably 350 parts by mass or more, with respect to 100 parts by mass of the peptizer. It is preferably 400 parts by mass or more, and the content is preferably 1000 parts by mass or less, more preferably 800 parts by mass or less, and even more preferably 600 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

The rubber composition contains saturated fatty acid glycerides.
As used herein, saturated fatty acid glycerides are mono-, di- or triglycerides in which a fatty acid is ester-bonded with glycerol (glycerin), and the constituent fatty acid portion is derived from a saturated fatty acid.

Fatty acids may be used singly or as a mixture of two or more. The fatty acid may be linear or branched, but linear is preferred.
Esters may be monoesters, diesters, or triesters, but monoesters (monoglycerides) are preferred.

The number of carbon atoms in the saturated fatty acid is preferably 4 or more, more preferably 6 or more, still more preferably 8 or more, particularly preferably 10 or more, most preferably 12 or more, most preferably 14 or more, and most preferably 16 or more. Yes, preferably 30 or less, more preferably 25 or less, still more preferably 20 or less. Within the above range, the effect tends to be obtained more favorably.

Examples of saturated fatty acid glycerides include glycerol monostearate, glycerol monolaurate, glycerol monomyristate, glycerol monopalmitylate, glycerol monoarachidylate, glycerol monobehelate, glycerol monocaprate, glycerol monomargallate, Saturated fatty acid monoglycerides such as glycerol monolignocerate and glycerol monocerothylate; glycerol distearate, glycerol dilaurate, glycerol dimyristylate, glycerol dipalmitylate, glycerol diarachidylate, glycerol dibehelate, glycerol dika Saturated fatty acid diglycerides such as plate, glycerol dimergallate, glycerol dilignocerate, glycerol diserotylate, glycerol monostearate monolaurate; glycerol tristearate, glycerol trilaurate, glycerol trimyristylate, glycerol Saturated fatty acid triglycerides such as tripalmitylate, glycerol triarachidylate, glycerol tribehelate, glycerol tricaprate, glycerol trimargallate, glycerol trilignocerate, glycerol tricerotylate, glycerol distearate monolaurate ; and the like. These may be used alone or in combination of two or more. Among them, saturated fatty acid monoglycerides are preferred, glycerol monostearate, glycerol monocaprate and glycerol monolaurate are more preferred, glycerol monostearate and glycerol monolaurate are still more preferred, and glycerol monostearate is particularly preferred.

As the saturated fatty acid glycerides, products such as Kao Corporation can be used.

The content of saturated fatty acid glycerides is preferably 0.1 parts by mass or more, more preferably 0.2 parts by mass or more, and still more preferably 0.3 parts by mass or more with respect to 100 parts by mass of the rubber component. The content is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 5 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

The rubber composition preferably contains carbon black and/or silica as a filler (reinforcing filler). Among them, it is preferable to contain carbon black and silica from the viewpoint that the above effects can be obtained more satisfactorily.

Examples of carbon black include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550 and N762. 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 80 m ² /g or more, more preferably 120 m ² /g or more, still more preferably 130 m ² /g or more. Also, the N ₂ SA is preferably 200 m ² /g or less, more preferably 170 m ² /g or less, still more preferably 155 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.

The dibutyl phthalate oil absorption (DBP) of carbon black is preferably 50 ml/100 g or more, more preferably 100 ml/100 g or more. Also, the DBP is preferably 200 ml/100 g or less, more preferably 135 ml/100 g or less. Within the above range, the effect tends to be obtained more favorably.
The DBP of carbon black can be measured according to JIS-K6217-4:2001.

As carbon black, for example, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., Lion Corporation, Shin Nikka Carbon Co., Ltd., Columbia Carbon Co., Ltd. can be used.

When carbon black is contained, the content of carbon black is preferably 2 parts by mass or more, more preferably 5 parts by mass or more, and still more preferably 20 parts by mass or more based on 100 parts by mass of the rubber component. The content is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 70 parts by mass or less, and particularly preferably 60 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

Silica is not particularly limited, and examples thereof include dry silica (anhydrous silicic acid) and wet silica (hydrous silicic acid). 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 N ₂ SA of silica is preferably 50 m ² /g or more, more preferably 150 m ² /g or more. Also, the N ₂ SA is preferably 300 m ² /g or less, more preferably 200 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.

When silica is contained, the content of silica relative to 100 parts by mass of the rubber component is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 20 parts by mass or more, and particularly preferably 40 parts by mass or more. . The content is preferably 120 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 80 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

In the rubber composition, the total content of carbon black and silica is 30 to 120 parts by mass with respect to 100 parts by mass of the rubber component. The total content is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, preferably 110 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 90 parts by mass or less, particularly preferably 80 parts by mass. Part by mass or less. Within the above range, the effect tends to be obtained more favorably.

When the rubber composition contains silica, it is preferable that the rubber composition contains a silane coupling agent together with silica.
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.

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.

When a silane coupling agent is contained, the content of the silane coupling agent is preferably 0.1 parts by mass or more, more preferably 2 parts by mass or more, and still more preferably 3 parts by mass or more with respect to 100 parts by mass of silica. is. Also, the content is preferably 20 parts by mass or less, more preferably 16 parts by mass or less, and even more preferably 12 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

The rubber composition may contain a plasticizer. The plasticizer is not particularly limited, but examples thereof include oils, liquid polymers (liquid diene-based polymers), and liquid resins. One type of these plasticizers may be used, or two or more types may be used in combination.

Among the plasticizers, it is preferably at least one selected from the group consisting of oils, liquid polymers, and liquid resins, more preferably oils and/or liquid polymers (liquid diene-based polymers), and further oil. preferable.

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, aromatic process oils are preferred. Specific examples of the aromatic process oil include the Diana process oil AH series manufactured by Idemitsu Kosan Co., Ltd., and the like.

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.

The liquid polymer (liquid diene-based polymer) is a diene-based polymer that is liquid at room temperature (25° C.).
The liquid diene-based polymer preferably has a polystyrene-equivalent weight-average molecular weight (Mw) measured by gel permeation chromatography (GPC) of 1.0×10 ³ or more, preferably 3.0×10 ³ or more. more preferably 2.0×10 ⁵ or less, more preferably 1.5×10 ⁴ or less.
In addition, in this specification, Mw of a liquid diene polymer is a polystyrene conversion value measured by gel permeation chromatography (GPC).

Liquid diene-based polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), and the like. be done. These may be used alone or in combination of two or more.

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

Examples of the liquid resin include, but are not limited to, liquid aromatic vinyl polymers, coumarone-indene resins, indene resins, terpene resins, rosin resins, and hydrogenated products thereof. These may be used alone or in combination of two or more.

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., ( Products of Nippon Shokubai Co., Ltd., JXTG Energy Co., Ltd., Arakawa Chemical Industry Co., Ltd., Taoka Chemical Industry Co., Ltd., etc. can be used.

When a plasticizer is contained, the content of the plasticizer (preferably oil) is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and still more preferably 10 parts by mass or more with respect to 100 parts by mass of the rubber component. , and particularly preferably 20 parts by mass or more. Also, the content is preferably 150 parts by mass or less, more preferably 100 parts by mass or less, even more preferably 80 parts by mass or less, and particularly preferably 60 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 the rubber (oil-extended rubber).

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.

When sulfur is contained, the content of sulfur is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and still more preferably 0.7 parts by mass or more with respect to 100 parts by mass of the rubber component. be. 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, N-oxyethylene-2-benzothiazolesulfenamide, N,N'-diisopropyl-2-benzothiazolesulfenamide; diphenylguanidine , diototolylguanidine and orthotolylbiguanidine. These may be used alone or in combination of two or more. Among these, sulfenamide-based vulcanization accelerators and guanidine-based vulcanization accelerators are preferred, and combined use of sulfenamide-based vulcanization accelerators and guanidine-based vulcanization accelerators is more preferred.

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.

When a vulcanization accelerator is contained, the content of the vulcanization accelerator 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. It is 10 parts by mass or less, more preferably 5 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

The rubber composition may contain a resin.
Although the resin is not particularly limited, for example, solid alkylphenol-based resin, styrene-based resin, coumarone-indene resin, terpene-based resin, rosin-based resin, acrylic-based resin, dicyclopentadiene-based resin (DCPD-based resin), etc. is mentioned. These may be used alone or in combination of two or more.

Examples of resins include Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Arizona Chemical, Nichinuri Chemical Co., Ltd. Products of Nippon Shokubai Co., Ltd., JXTG Energy Co., Ltd., Arakawa Chemical Co., Ltd., Taoka Chemical Co., Ltd., etc. can be used.

When a resin is contained, the content of the resin is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and still more preferably 5 parts by mass or more with respect to 100 parts by mass of the rubber component. Also, the content is preferably 80 parts by mass or less, more preferably 50 parts by mass or less, and even more preferably 20 parts by mass or less.

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

When stearic acid is contained, the content of stearic acid 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.

When zinc oxide is contained, 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 with respect to 100 parts by mass of the rubber component. , more preferably 5 parts by mass or less. 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.

When an anti-aging agent is contained, 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 with respect to 100 parts by mass of the rubber component. parts or less, more preferably 5 parts by mass or less. Within the above range, the effect tends to be obtained more favorably.

The rubber composition preferably contains 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.

When wax is contained, 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, vulcanizing agents other than sulfur (e.g., organic cross-linking agents, organic peroxides), Examples include mica such as calcium carbonate and sericite, aluminum hydroxide, magnesium oxide, magnesium hydroxide, clay, talc, alumina, and titanium oxide. 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.

For the reason that the effect can be obtained more preferably, the rubber composition is
a mastication step of kneading an isoprene-based rubber, a peptization accelerator, and a hydrazide compound;
a base kneading step of kneading the kneaded product obtained by the mastication step and saturated fatty acid glycerides;
It is preferably produced by a production method including a kneaded product obtained in the base kneading step, and a finishing kneading step of kneading a cross-linking agent (vulcanizing agent) and a vulcanization accelerator.
In the base kneading step, it is preferable to further knead carbon black and/or silica (preferably carbon black and silica) in addition to the above components. Thereby, an effect is obtained more suitably.

As for kneading conditions, the kneading temperature is usually 100 to 180° C., preferably 120 to 170° C. in the mastication step and the base kneading step. In the finishing kneading step, 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.

Examples of the rubber composition include tread (cap tread), sidewall, base tread, undertread, clinch, bead apex, breaker cushion rubber, carcass cord covering rubber, insulation, chafer, inner liner, etc. It can be used for tire members such as side reinforcing layers of run-flat tires (as a rubber composition for tires). Among others, it is preferably used for treads.

The tire (pneumatic tire, solid tire, airless tire, etc.) of the present invention 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 the unvulcanized stage according to the shape of each tire member (especially the tread (cap tread)), and is placed on a tire building machine. After forming an unvulcanized tire by molding by a normal method with other tire members 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 above tires include tires for passenger cars, tires for large passenger cars, tires for large SUVs, tires for trucks and buses, tires for motorcycles, racing tires, studless tires (winter tires), all-season tires, run-flat tires, and aircraft tires. , mining tires and the like.

EXAMPLES The present invention will be specifically described based on Examples, but the present invention is not limited to these.

Various chemicals used in Examples and Comparative Examples are collectively described below.
Natural rubber (NR): TSR20
Peptizer: Noctizer SD manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd. (mixture of o,o'-dibenzamide diphenyl disulfide and additives such as stearic acid, melting point: 54°C)
Hydrazide compound 1: adipic acid dihydrazide hydrazide manufactured by Tokyo Chemical Industry Co., Ltd. Compound 2: n-octanohydrazide (octanoic acid hydrazide) manufactured by Tokyo Chemical Industry Co., Ltd.
Hydrazide compound 3: Isophthalic acid dihydrazide butadiene rubber (BR) manufactured by Tokyo Chemical Industry Co., Ltd.: Ubepol BR150B manufactured by Ube Industries, Ltd. (cis content: 98% by mass)
Carbon black: SEAST 9 SAF (N ₂ SA: 142 m ² /g, DBP: 115 ml/100 g) manufactured by Tokai Carbon Co., Ltd.
Silica: VN3 (N ₂ SA: 175 m ² /g) manufactured by EVONIK-DEGUSSA
Saturated fatty acid glyceride 1: Glycerol monostearate, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Saturated fatty acid glyceride 2: Glycerol monocaprate, manufactured by Tokyo Chemical Industry Co., Ltd. Saturated fatty acid glyceride 3: Glycerol mono, manufactured by Tokyo Chemical Industry Co., Ltd. Laurate process oil: process oil NR manufactured by Idemitsu Kosan Co., Ltd.
Silane coupling agent: Si69 (bis(3-triethoxysilylpropyl)tetrasulfide) from EVONIK-DEGUSSA
Stearic acid: stearic acid "Tsubaki" manufactured by NOF Corporation
Wax: Sannok N manufactured by Ouchi Shinko Chemical Co., Ltd.
Antiaging agent: Antigen 6C (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine) manufactured by Sumitomo Chemical Co., Ltd.
Zinc oxide: Type 2 zinc oxide manufactured by Mitsui Kinzoku Kogyo Co., Ltd. Sulfur: Powdered sulfur manufactured by Karuizawa Sulfur Co., Ltd. Vulcanization accelerator 1: Noxceler NS (N-t-butyl -2-benzothiazolylsulfenamide)
Vulcanization accelerator 2: Noxceler D (1,3-diphenylguanidine) manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.

[Examples and Comparative Examples]
(1) Mastication process Using a Banbury mixer, the rubber component was masticated for 1.5 minutes at a discharge temperature of 150°C according to the formulations shown in Tables 1 to 3 to obtain masticated rubber.
(2) Base kneading step To the masticated rubber obtained in the masticating step (1), according to the compounding content shown in Tables 1 to 3, the compounding ingredients described in the item of the base kneading step are added, and the mixture is mixed using a Banbury mixer. , and kneaded for 2.5 minutes at a discharge temperature of 150°C to obtain a kneaded product.
(3) Finish kneading process Using an open roll, the materials described in the items of the finish kneading process are added to the kneaded product obtained in the base kneading process (2) according to the formulations shown in Tables 1 to 3 and kneaded. The mixture was kneaded and discharged when the rubber temperature reached about 110°C to obtain an unvulcanized rubber composition.
(4) Vulcanization step The unvulcanized rubber composition obtained in the step (3) is molded into a 2 mm flat sheet and press-vulcanized at 170°C for 10 minutes in a 2 mm thick mold to obtain a vulcanized rubber. A composition was obtained.

The unvulcanized rubber composition and the vulcanized rubber composition thus obtained were used for the following evaluations. The results are shown in Tables 1-3. The standard comparative example in Table 1 is Comparative Example 1, the standard comparative example in Table 2 is Comparative Example 5, and the standard comparative example in Table 3 is Comparative Example 9.

<Destruction Property Index>
Based on JIS K6251: 2010, a dumbbell-shaped No. 6 test piece was prepared from the obtained vulcanized rubber composition, and a tensile test was performed using the test piece in an atmosphere of 25 ° C. Breaking strength TB (MPa ) and the elongation at break EB (%) were measured. Then, TB×EB/2 (MPa·%) was calculated. The results were indexed with the result of the reference comparative example set to 100. A larger index indicates better breaking properties.

<RR index>
Using a viscoelastic spectrometer VES (manufactured by Iwamoto Seisakusho Co., Ltd.), the loss tangent (tan δ) of the vulcanized rubber composition was measured under the conditions of a temperature of 30 ° C., a frequency of 10 Hz, an initial strain of 10% and a dynamic strain of 2%. was measured and indexed with the reference comparative example being 100. A larger index indicates lower rolling resistance and better fuel efficiency.

<Processability index (Mooney viscosity)>
The obtained unvulcanized rubber composition was measured for Mooney viscosity at 130° C. according to the method for measuring Mooney viscosity according to JIS K 6300. The value of the reference comparative example was set to 100 and indicated as an index. The larger the index, the lower the viscosity and the better the workability.

From Tables 1 to 3, the total content of carbon black and silica is 30 to 120 parts by mass based on 100 parts by mass of the rubber component, including isoprene-based rubber, peptizer, hydrazide compound, and saturated fatty acid glycerides. In the example, the overall performance of workability, fuel economy, and breaking properties was improved.

Comparison of Comparative Examples 1 to 4 and Examples 1 and 2, Comparison of Comparative Examples 5 to 8, Comparison of Examples 3 and 4, Comparison of Comparative Examples 9 to 12, and Comparison of Examples 5 and 6 revealed that "hydrazide compound" and " Saturated fatty acid glycerides" were found to synergistically improve the overall performance of workability, fuel efficiency and breaking properties.

Claims (5)

It contains an isoprene-based rubber, a peptizer, a hydrazide compound, and saturated fatty acid glycerides, and the total content of carbon black and silica is 30 to 120 parts by mass with respect to 100 parts by mass of the rubber component,
A rubber composition for a tire, wherein the saturated fatty acid glyceride content is 0.2 to 20 parts by mass with respect to 100 parts by mass of the rubber component . The rubber composition for tires according to claim 1, wherein the content of said hydrazide compound is 0.3 to 1.2 parts by mass with respect to 100 parts by mass of isoprene rubber. The rubber composition for tires according to claim 1 or 2, comprising carbon black and silica. The rubber composition for tires according to any one of claims 1 to 3, which is a rubber composition for treads. A tire having a tread using the rubber composition according to any one of claims 1 to 4.