Rubber composition and tire

Abstract

To provide a rubber composition that has excellent workability in unvulcanized rubber while having excellent tear strength in vulcanized rubber, and to provide a tire having excellent steering stability.SOLUTION: A rubber composition comprises a rubber component, and 3-t-butyl-5-pyrazolone and / or a salt thereof.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a rubber composition and a tire.

Background Art

[0002] In recent years, automobiles have become significantly more high-performance and high-output, and high durability is also required for tires that come into contact with the road surface. Among such durability, high mechanical strength, more specifically, high tear strength is required, and rubber additives for this purpose are needed.

[0003] The applicant of the present application has developed a technique capable of imparting an effect of improving tear strength to a rubber component by blending a pyrazolone compound typified by 3-methyl-5-pyrazolone into the rubber component (Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a rubber composition having excellent processability in an unvulcanized rubber and excellent tear strength in a vulcanized rubber.

[0006] An object of the present invention is to provide a tire having excellent handling stability.

Means for Solving the Problems

[0007] The present inventor has intensively studied to solve the above problems.

[0008] The present inventors have found that a specific pyrazolone-based compound can impart excellent tear strength to a rubber composition containing a rubber component, and can also impart excellent processability (Mooney viscosity) to unvulcanized rubber.

[0009] The present inventors have found that a specific pyrazolone-based compound can impart excellent handling stability to a tire containing a rubber component.

[0010] In these rubber compositions, an increase in viscosity is suppressed in the unvulcanized state, workability is improved, tear strength is improved after vulcanization, and handling stability is improved in tires manufactured using this rubber composition.

[0011] Based on such findings, the present inventors further studied and as a result, completed the present invention.

[0012] That is, the present invention includes a rubber composition, a tire, and a method for producing a rubber composition, as shown below.

[0013] Item 1. A rubber composition containing a rubber component, 3-t-butyl-5-pyrazolone, and / or a salt thereof.

[0014] Item 2. The rubber composition according to Item 1 above, wherein the rubber component is at least one rubber component selected from the group consisting of natural rubber, isoprene rubber, styrene-butadiene copolymer rubber, and butadiene rubber.

[0015] Item 3. The rubber composition according to Item 1 or 2 above, further containing carbon black and / or an inorganic filler.

[0016] Item 4. The rubber composition according to Item 3 above, containing 0.1 to 50 parts by mass of 3-t-butyl-5-pyrazolone and / or a salt thereof, and 20 to 200 parts by mass of carbon black and / or an inorganic filler, per 100 parts by mass of the rubber component.

[0017] Item 5. A tire produced using the rubber composition according to any one of Items 1 to 4 above.

[0018] Item 6. A method for producing a rubber composition, comprising: (1) A step of mixing a raw material component containing a rubber component, 3-t-butyl-5-pyrazolone and / or a salt thereof, and carbon black and / or an inorganic filler, and (2) A step of mixing the mixture obtained in the step (1) and a vulcanizing agent. including production method.

Effects of the Invention

[0019] An object of the present invention is to provide a rubber composition having excellent processability in an unvulcanized rubber and excellent tear strength in a vulcanized rubber.

[0020] Another object of the present invention is to provide a tire having excellent handling stability.

Modes for Carrying Out the Invention

[0021] The present invention will be described in detail below.

[0022] In this specification, "comprising" and "containing" are concepts that include any of "comprise", "consist essentially of", and "consist of".

[0023] In this specification, when a numerical range is represented as "A to B", it means A or more and B or less.

[0024] [1] Rubber composition The rubber composition of the present invention contains a rubber component, and 3-t-butyl-5-pyrazolone and / or a salt thereof.

[0025] In the rubber composition of the present invention, the rubber component is preferably a diene rubber.

[0026] In the rubber composition of the present invention, the rubber component is preferably at least one rubber component selected from the group consisting of natural rubber, isoprene rubber, styrene-butadiene copolymer rubber, and butadiene rubber.

[0027] The rubber composition of the present invention preferably further contains carbon black and / or an inorganic filler.

[0028] In the rubber composition of the present invention, preferably, 0.1 to 50 parts by mass of 3-t-butyl-5-pyrazolone and / or its salt, and 20 to 200 parts by mass of carbon black and / or an inorganic filler are contained per 100 parts by mass of the rubber component.

[0029] Since the rubber composition of the present invention contains 3-t-butyl-5-pyrazolone and / or its salt, an increase in the viscosity of the unvulcanized rubber composition is suppressed, and the processability (workability) is excellent.

[0030] Since the rubber composition of the present invention contains 3-t-butyl-5-pyrazolone and / or its salt, the tear strength of the vulcanized rubber composition is excellent.

[0031] Since the rubber composition of the present invention contains 3-t-butyl-5-pyrazolone and / or its salt, the handling stability of the tire manufactured using the vulcanized rubber composition is excellent.

[0032] [1-1] Rubber component The rubber composition of the present invention contains a rubber component.

[0033] The rubber component is not particularly limited, and is preferably natural rubber (NR), synthetic diene rubber, a mixture of natural rubber and synthetic diene rubber, and non-diene rubber other than these.

[0034] Natural rubber preferably includes natural rubber latex, technically classified rubber (TSR), smoked sheet (RSS), gutta-percha, natural rubber derived from Eucommia ulmoides, natural rubber derived from guayule, natural rubber derived from Russian dandelion, etc.

[0035] Natural rubber includes modified natural rubber obtained by modifying the above natural rubber. Modified natural rubber preferably includes modified natural rubbers such as epoxidized natural rubber, methacrylic acid-modified natural rubber, styrene-modified natural rubber, etc.

[0036] Synthetic diene rubber preferably includes styrene-butadiene copolymer rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), nitrile rubber (NBR), chloroprene rubber (CR), ethylene-propylene-diene terpolymer rubber (EPDM), styrene-isoprene-styrene triblock copolymer (SIS), styrene-butadiene-styrene triblock copolymer (SBS), etc.

[0037] Synthetic diene rubber includes modified synthetic diene rubber obtained by modifying the above synthetic diene rubber. Modified synthetic diene rubber preferably includes diene rubbers according to modification methods such as main chain modification, one-end modification, both-end modification, etc. The modifying functional groups of the modified synthetic diene rubber are preferably various functional groups such as epoxy group, amino group, alkoxysilyl group, hydroxyl group, etc., and one kind or two or more kinds of these functional groups may be included in the modified synthetic diene rubber.

[0038] The production method of synthetic diene rubber is not particularly limited and includes emulsion polymerization, solution polymerization, radical polymerization, anionic polymerization, cationic polymerization, etc. The glass transition point of synthetic diene rubber is not particularly limited.

[0039] The ratio of cis / trans / vinyl at the double bond part of natural rubber and synthetic diene rubber is not particularly limited, and it can be preferably used in any ratio.

[0040] The number average molecular weight and molecular weight distribution of the diene rubber are not particularly limited, and the number average molecular weight is preferably about 500 to 3,000,000, and the molecular weight distribution is preferably about 1.5 to 15.

[0041] In the rubber composition of the present invention, the rubber component may be used alone or in combination (blended) of two or more kinds.

[0042] In the rubber composition of the present invention, as the rubber component, preferably, it contains at least one rubber component selected from the group consisting of the above rubber components, more preferably, it contains at least one rubber component selected from the group consisting of NR, IR, SBR, and BR, and still more preferably, it contains at least one rubber component selected from the group consisting of NR, SBR, and BR.

[0043] In the rubber composition of the present invention, the blend ratio of the rubber component is not particularly limited.

[0044] As the blend ratio of the rubber component, it is preferable to blend NR, SBR, BR or a mixture of two or more selected therefrom in a ratio of 50 parts by mass to 100 parts by mass, and more preferably 75 parts by mass to 100 parts by mass, per 100 parts by mass of the rubber component.

[0045] When blending a mixture of SBR and BR as the rubber component, as the blend ratio thereof, the total amount of SBR and BR is preferably 50 parts by mass to 100 parts by mass, and more preferably 75 parts by mass to 100 parts by mass, per 100 parts by mass of the rubber component. Also, the blending amount of SBR at this time is preferably 50 parts by mass to 100 parts by mass, and the blending amount of BR is preferably 0 to 50 parts by mass.

[0046] [1-2] 3-t-butyl-5-pyrazolone and / or its salt The rubber composition of the present invention contains 3-t-butyl-5-pyrazolone and / or its salt.

[0047] 3-t-butyl-5-pyrazolone is a pyrazolone compound represented by the following structural formula.

[0048]

Chem.

[0049] 3-t-Butyl-5-pyrazolone forms tautomers. When tautomerization is possible (e.g., in solution), a chemical equilibrium of tautomers can be reached.

[0050] 3-t-Butyl-5-pyrazolone exists as tautomers represented by, for example, the following compounds.

[0051]

Chem.

[0052] Both 3-t-butyl-5-pyrazolone and its tautomers have reached an equilibrium state where both isomers coexist.

[0053] Unless otherwise specified, the 3-t-butyl-5-pyrazolone included in the present invention encompasses all the above-mentioned tautomeric forms.

[0054] Also, 3-t-butyl-5-pyrazolone may be in the form of a salt, and there is no particular limitation on the salt of 3-t-butyl-5-pyrazolone, and all kinds of salts are included. Such salts include, for example, inorganic acid salts such as hydrochloride, sulfate, nitrate, etc.; organic acid salts such as acetate, methanesulfonate, etc.; alkali metal salts such as sodium salt, potassium salt, etc.; alkaline earth metal salts such as magnesium salt, calcium salt, etc.; ammonium salts such as dimethylammonium, triethylammonium, etc.

[0055] In the rubber composition of the present invention, 3-t-butyl-5-pyrazolone and / or its salt is preferably contained in an amount of 0.1 part by mass to 50 parts by mass, more preferably 0.1 part by mass to 20 parts by mass, and still more preferably 0.2 part by mass to 10 parts by mass, based on 100 parts by mass of the rubber component.

[0056] In the rubber composition of the present invention, due to the t-butyl group at the 3-position of 3-t-butyl-5-pyrazolone, it is possible to suppress the deterioration of the processability of the rubber composition.

[0057] In the rubber composition of the present invention, upon the reaction of 3-t-butyl-5-pyrazolone and / or its salt during the vulcanization of the rubber composition, it is possible to improve the tear strength of the rubber composition and improve the handling stability of the tire.

[0058] [1-3] Carbon black and / or inorganic filler The rubber composition of the present invention preferably further contains carbon black and / or an inorganic filler.

[0059] Carbon black In this specification, the inorganic filler does not contain carbon black.

[0060] Carbon black is used to improve the reinforcing property of the rubber.

[0061] Carbon black is not particularly limited, and examples thereof include commercially available carbon black, Carbon-Silica Dual phase filler, etc.

[0062] By containing carbon black in the rubber component, it is possible to lower the electrical resistance of the rubber, exhibit the effect of suppressing charging, and further improve the strength of the rubber.

[0063] Carbon black is preferably carbon black of high, medium or low structure SAF, ISAF, IISAF, N110, N134, N220, N234, N330, N339, N375, N550, HAF, FEF, GPF, SRF grades, etc. Carbon black is preferably carbon black of SAF, ISAF, IISAF, N134, N234, N330, N339, N375, HAF, FEF grades.

[0064] The range of the DBP absorption amount of carbon black is preferably 60 cm3 / 100 g to 200 cm 3 / 100 g, more preferably 70 cm 3 / 100 g to 180 cm 3 / 100 g, particularly preferably 80 cm 3 / 100 g to 160 cm 3 / 100 g.

[0065] The nitrogen adsorption specific surface area (N2SA) of carbon black is measured in accordance with JIS K6217-2:2001. The range of the nitrogen adsorption specific surface area of carbon black is preferably 30 m 2 / g to 200 m 2 / g, more preferably 40 m 2 / g to 180 m 2 / g, particularly preferably 50 m 2 / g to 160 m 2 / g.

[0066] Inorganic filler There is no particular limitation on the inorganic filler, and inorganic compounds that are usually used in the rubber industry are used.

[0067] The inorganic compound is preferably silica.

[0068] The inorganic compound is preferably alumina (Al2O3) such as γ-alumina and α-alumina.

[0069] The inorganic compound is preferably alumina monohydrate (Al2O3·H2O) such as boehmite and diaspore.

[0070] The inorganic compound is preferably aluminum hydroxide [Al(OH)3] such as gibbsite and bayerite.

[0071] The inorganic compound is preferably aluminum carbonate [Al2(CO3)3], magnesium hydroxide [Mg(OH)2], magnesium oxide (MgO), magnesium carbonate (MgCO3), talc (3MgO·4SiO2·H2O), attapulgite (5MgO·8SiO2·9H2O), titanium white (TiO2), titanium black (TiO 2n-1 ), calcium oxide (CaO), calcium hydroxide [Ca(OH)2], magnesium aluminum oxide (MgO·Al2O3), clay (Al2O3·2SiO2), kaolin (Al2O3·2SiO2·2H2O), 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.), calcium aluminum silicate (Al2O3·CaO·2SiO2, etc.), calcium magnesium silicate (CaMgSiO4), calcium carbonate (CaCO3), zirconium oxide (ZrO2), zirconium hydroxide [ZrO(OH)2·nH2O], zirconium carbonate [Zr(CO3)2], zinc acrylate, zinc methacrylate, etc.

[0072] The inorganic compound is preferably a crystalline aluminosilicate containing hydrogen, an alkali metal, or an alkaline earth metal that corrects the charge, such as various zeolites.

[0073] The inorganic filler may preferably have its surface organically treated in order to improve the affinity with the rubber component.

[0074] From the viewpoint of imparting rubber strength, the inorganic filler is preferably silica, more preferably silica used alone, or a combination of silica and one or more inorganic compounds commonly used in the rubber industry.

[0075] When silica is used in combination with the inorganic compound other than silica as the inorganic filler, it may be appropriately adjusted so that the total amount of all components of the inorganic filler falls within the above range.

[0076] From the viewpoint of being able to impart rubber strength, the inorganic filler is preferably silica.

[0077] The silica is preferably wet silica, dry silica, or colloidal silica, more preferably wet silica.

[0078] The silica may preferably have its surface organically treated in order to improve its affinity with the rubber component.

[0079] The BET specific surface area of the silica is measured in accordance with ISO5794 / 1. The range of the BET specific surface area of the silica is preferably in the range of 40 m 2 / g to 350 m 2 / g. Silica having a BET specific surface area within this range has the advantage of being able to achieve both rubber reinforcement and dispersibility in the rubber component. The BET specific surface area of the silica is more preferably 80 m 2 / g to 300 m 2 / g, even more preferably 100 m 2 / g to 270 m 2 / g, and particularly preferably 110 m 2 / g to 270 m 2 / g.

[0080] Commercially available silicas include products named "HD165MP" (BET specific surface area = 165 m 2 / g), "HD115MP" (BET specific surface area = 115 m 2 / g), "HD200MP" (BET specific surface area = 200 m 2 / g), "HD250MP" (BET specific surface area = 250 m 2 / g) manufactured by Quechen Silicon Chemical Co., Ltd., products named "Nip Seal AQ" (BET specific surface area = 205 m 2 / g), "Nip Seal KQ" (BET specific surface area = 240 m 2 / g) manufactured by Tosoh Silica Corporation, and products named "Ultrasil VN3" (BET specific surface area = 175 m 2 / g) manufactured by Degussa, etc.

[0081] Blending amount of carbon black and / or inorganic filler In the rubber composition of the present invention, the carbon black and / or inorganic filler may be used alone or in combination (blended) of two or more kinds.

[0082] In the rubber composition of the present invention, based on 100 parts by mass of the rubber component, the carbon black and / or inorganic filler is preferably contained in an amount of 20 to 200 parts by mass, more preferably 30 to 130 parts by mass, and still more preferably 35 to 110 parts by mass.

[0083] From the viewpoint of improving the reinforcing property of the rubber composition, the blending amount of the carbon black and / or inorganic filler is preferably 20 parts by mass or more, and from the viewpoint of improving the tear strength, it is preferably 200 parts by mass or less.

[0084] When both the carbon black and the inorganic filler are blended, they may be appropriately adjusted so that the total amount of the two components falls within the above range.

[0085] The blending amount of the carbon black is preferably 2 to 200 parts by mass, more preferably 30 to 130 parts by mass, and still more preferably 35 to 100 parts by mass with respect to 100 parts by mass of the rubber component.

[0086] From the viewpoint of ensuring the antistatic performance and rubber strength performance, the blending amount of the carbon black is preferably 2 parts by mass or more, and from the viewpoint of improving the tear strength, it is preferably 200 parts by mass or less.

[0087] The blending amount of the inorganic filler is preferably 2 to 200 parts by mass, more preferably 30 to 130 parts by mass, and still more preferably 35 to 100 parts by mass with respect to 100 parts by mass of the rubber component.

[0088] When silica is used as the inorganic filler, the compounding amount of silica is preferably 2 parts by mass to 200 parts by mass, more preferably 30 parts by mass to 130 parts by mass, and still more preferably 35 parts by mass to 100 parts by mass with respect to 100 parts by mass of the rubber component.

[0089] [1-4] Other compounding agents In addition to the rubber component, 3-t-butyl-5-pyrazolone and / or its salt, and carbon black and / or inorganic filler, the rubber composition of the present invention can appropriately select and blend compounding agents usually used in the rubber industry.

[0090] Examples of the compounding agents include antioxidants, antiozonants, softeners, processing aids, waxes, resins, foaming agents, oils, stearic acid, zinc oxide (ZnO), vulcanization accelerators, vulcanization retarders, vulcanizing agents (such as sulfur), etc.

[0091] When the rubber composition of the present invention contains inorganic fillers such as carbon black and silica, for the purpose of enhancing the reinforcing property of the rubber composition and enhancing the abrasion resistance together with the tear strength of the rubber composition depending on carbon black, silica, etc., a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, a zirconate coupling agent, etc. may be blended in the rubber composition.

[0092] Silane coupling agent The silane coupling agent that can be used in combination with carbon black and / or inorganic filler is preferably a silane coupling agent such as a sulfide-based, polysulfide-based, thioester-based, thiol-based, olefin-based, epoxy-based, amino-based, alkyl-based silane coupling agent.

[0093] Sulfide-based silane coupling agents are preferably bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(3-methyldimethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(3-methyldimethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-trimethoxysilylpropyl)trisulfide, bis(3-methyldimethoxysilylpropyl)trisulfide, bis(2-triethoxysilylethyl)trisulfide, 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, etc. The sulfide-based silane coupling agent is more preferably bis(3-triethoxysilylpropyl)tetrasulfide.

[0094] Thioester-based silane coupling agents, preferably 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 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, etc.

[0095] Thiol-based silane coupling agents are preferably 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-[ethoxybis(3,6,9,12,15-pentaoxaoctacosane-1-yloxy)silyl]-1-propanethiol, etc.

[0096] Olefin-based silane coupling agents are preferably dimethoxymethylvinylsilane, vinyltrimethoxysilane, dimethylethoxyvinylsilane, diethoxymethylvinylsilane, triethoxyvinylsilane, vinyltris(2-methoxyethoxy)silane, allyltrimethoxysilane, allyltriethoxysilane, p-styryltrimethoxysilane, 3-(methoxydimethoxydimethylsilyl)propyl acrylate, 3-(trimethoxysilyl)propyl acrylate, 3-[dimethoxy(methyl)silyl]propyl methacrylate, 3-(trimethoxysilyl)propyl methacrylate, 3-[dimethoxy(methyl)silyl]propyl methacrylate, 3-(triethoxysilyl)propyl methacrylate, 3-[tris(trimethylsiloxy)silyl]propyl methacrylate, etc.

[0097] Epoxy-based silane coupling agents are preferably 3-glycidyloxypropyl(dimethoxy)methylsilane, 3-glycidyloxypropyltrimethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, triethoxy(3-glycidyloxypropyl)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc. More preferably, the epoxy-based silane coupling agent is 3-glycidyloxypropyltrimethoxysilane.

[0098] Amino-based silane coupling agents are preferably N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-ethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, etc. More preferably, the amino-based silane coupling agent is 3-aminopropyltriethoxysilane.

[0099] Alkyl-based silane coupling agents are preferably methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, etc.

[0100] More preferably, the alkyl-based silane coupling agent is methyltriethoxysilane.

[0101] The silane coupling agent is particularly preferably bis(3-triethoxysilylpropyl)tetrasulfide.

[0102] Titanate coupling agent A titanate coupling agent that can be used in combination with carbon black and / or an inorganic filler, preferably a titanate coupling agent such as an alkoxide-based, chelate-based, or acylate-based one.

[0103] The alkoxide-based titanate coupling agent is preferably tetraisopropyl titanate, tetra-n-butyl titanate, butyl titanate dimer, tetraoctyl titanate, tetra-tert-butyl titanate, tetrastearyl titanate, etc. The alkoxide-based titanate coupling agent is more preferably tetraisopropyl titanate.

[0104] The chelate-based titanate coupling agent is preferably titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetoacetate, titanium dodecylbenzenesulfonate compound, titanium phosphate compound, titanium octylene glycolate, titanium ethylacetoacetate, titanium lactate ammonium salt, titanium lactate, titanium ethanolamineate, titanium octylene glycolate, titanium aminoethylaminoethanolate, etc. The chelate-based titanate coupling agent is more preferably titanium acetylacetonate.

[0105] The acylate-based titanate coupling agent is preferably titanium isostearate, etc.

[0106] Aluminate coupling agent An aluminate coupling agent that can be used in combination with carbon black and / or an inorganic filler is preferably aluminum diisopropylate 9-octadecenylacetoacetate, aluminum secondary butoxide, aluminum trisacetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, aluminum trisethylacetoacetate, etc.

[0107] The aluminate coupling agent is more preferably aluminum diisopropylate 9 - octadecenylacetoacetate.

[0108] Zirconate coupling agent The zirconate coupling agent that can be used in combination with carbon black and / or inorganic fillers is preferably a zirconate coupling agent such as an alkoxide - type, chelate - type, acylate - type, etc.

[0109] The alkoxide - type zirconium - based coupling agent is preferably normal propyl zirconate, normal butyl zirconate, etc. The alkoxide - type zirconium - based coupling agent is more preferably normal butyl zirconate.

[0110] The chelate - type zirconate coupling agent is preferably zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium ethyl acetoacetate, zirconium lactate ammonium salt, etc. The chelate - type zirconate coupling agent is more preferably zirconium tetraacetylacetonate.

[0111] The acylate - type zirconate coupling agent is preferably zirconium stearate, zirconium octylate, etc. The acylate - type zirconate coupling agent is more preferably zirconium stearate.

[0112] Blending amount of silane coupling agent, titanate coupling agent, aluminate coupling agent, zirconate coupling agent, etc. In the rubber composition of the present invention, silane coupling agents, titanate coupling agents, aluminate coupling agents, zirconate coupling agents, etc. may be used alone or may be used as a mixture (blend) of two or more.

[0113] In the rubber composition of the present invention, the compounding amount of the silane coupling agent is preferably 0.1 part by mass to 20 parts by mass, more preferably 3 parts by mass to 15 parts by mass, based on 100 parts by mass of carbon black and / or inorganic filler. By setting the compounding amount of the silane coupling agent to 0.1 part by mass or more based on 100 parts by mass of carbon black and / or inorganic filler, the effect of improving the tear strength of the rubber composition can be more suitably exhibited. By setting it to 20 parts by mass or less, the cost of the rubber composition can be reduced and the economy can be improved.

[0114] [2] Manufacturing method of rubber composition The method for producing the rubber composition of the present invention is (1) A step of mixing raw material components including a rubber component, 3-t-butyl-5-pyrazolone and / or its salt, and carbon black and / or inorganic filler, and (2) A step of mixing the mixture obtained in the step (1) and a vulcanizing agent (such as sulfur). It includes.

[0115] Step (1) Step (1) is a step of kneading raw material components including a rubber component, 3-t-butyl-5-pyrazolone and / or its salt, and carbon black and / or inorganic filler, and is a step before compounding a vulcanizing agent.

[0116] The kneading method in step (1) is, for example, a method of kneading a composition containing a rubber component, 3-t-butyl-5-pyrazolone and / or its salt, and raw material components such as carbon black and / or inorganic filler. In step (1), other compounding agents and the like can be further compounded as necessary.

[0117] The kneading method may be to knead the total amount of each component at once, or according to the purpose such as viscosity adjustment, each component may be added in portions and kneaded. Also, after kneading the rubber component with carbon black and / or inorganic filler, 3-t-butyl-5-pyrazolone and / or its salt may be added and kneaded, or after kneading the rubber component with 3-t-butyl-5-pyrazolone and / or its salt, carbon black and / or inorganic filler may be added and kneaded. In order to uniformly disperse each component, the kneading operation may be repeated.

[0118] The kneading temperature in step (1) is preferably such that the upper limit of the temperature of the rubber composition is 100°C to 190°C, more preferably 110°C to 175°C, and still more preferably 120°C to 170°C.

[0119] The kneading time in step (1) is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and still more preferably 1 minute to 8 minutes.

[0120] Two-stage kneading in step (1) Another kneading method in step (1) is Step (1-1) of kneading the rubber component with 3-t-butyl-5-pyrazolone and / or its salt, and Step (1-2) of kneading the mixture obtained in the above step (1-1) with the raw material components containing carbon black and / or inorganic filler A two-stage kneading method including the above may be adopted.

[0121] The kneading temperature in step (1-1) is preferably 60°C to 190°C, more preferably 70°C to 160°C, and still more preferably 80°C to 150°C. By adjusting the kneading temperature to 60°C to 190°C, the reaction proceeds well and the deterioration of the rubber can be suppressed.

[0122] The kneading time of step (1-1) is preferably from 10 seconds to 20 minutes, more preferably from 30 seconds to 10 minutes, and still more preferably from 60 seconds to 7 minutes. By adjusting the kneading time to 10 seconds to 20 minutes, the reaction proceeds well and the productivity can be improved.

[0123] The kneading temperature of step (1-2) is preferably such that the upper limit of the temperature of the mixture is from 100°C to 190°C, more preferably from 130°C to 175°C, and still more preferably from 110°C to 170°C.

[0124] The kneading time of step (1-2) is preferably from 10 seconds to 20 minutes, more preferably from 30 seconds to 10 minutes, and still more preferably from 1 minute to 8 minutes.

[0125] In step (1) and step (1-1), the compounding amount of 3-t-butyl-5-pyrazolone and / or its salt is preferably from 0.1 part by mass to 50 parts by mass, more preferably from 0.1 part by mass to 20 parts by mass, and still more preferably from 0.2 part by mass to 10 parts by mass with respect to 100 parts by mass of the rubber component.

[0126] Due to the rubber composition of the present invention containing 3-t-butyl-5-pyrazolone and / or its salt, it is possible to suppress the deterioration of the processability of the rubber composition prepared in step (1).

[0127] When proceeding from step (1) to step (2), preferably, after the temperature at the end of step (1) is lowered by 30°C or more, then proceed to the next step (2).

[0128] Step (2) Step (2) is a step of mixing the mixture obtained in step (1) and a vulcanizing agent (such as sulfur), and is the final stage of kneading.

[0129] In step (2), a vulcanization accelerator or the like can be further compounded as necessary.

[0130] Step (2) is preferably carried out under heating conditions, and the heating temperature is preferably 60°C to 140°C, more preferably 80°C to 120°C, and still more preferably 90°C to 120°C.

[0131] The mixing (or kneading) time of step (2) is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and still more preferably 60 seconds to 5 minutes.

[0132] Due to the rubber composition of the present invention containing 3-t-butyl-5-pyrazolone and / or its salt, it is possible to suppress the deterioration of the processability of the rubber composition prepared in step (2).

[0133] Addition of other compounding agents In the method for producing the rubber composition of the present invention, in step (1) (step (1-1) and step (1-2)), and step (2), if necessary, various compounding agents such as stearic acid, zinc oxide, vulcanization accelerator, antioxidant, etc. compounded in the rubber composition can be added.

[0134] Other compounding agents may be added either in step (1) or step (2), or may be added separately in step (1) and step (2).

[0135] [3] Tire The present invention includes tires produced using the rubber composition of the present invention.

[0136] The rubber composition of the present invention is mixed or kneaded using a Banbury mixer, roll, intensive mixer, kneader, single-screw extruder, twin-screw extruder, etc.

[0137] Subsequently, the rubber composition is extruded and processed in an extrusion process, and is formed, for example, into a tread member or a sidewall member.

[0138] Subsequently, the rubber composition is pasted and formed on a tire molding machine according to a normal method to form a green tire.

[0139] This raw tire is heated and pressurized in a vulcanizer to obtain a tire.

[0140] Tire and other applications The tire of the present invention is produced using the rubber composition of the present invention.

[0141] The tire is preferably a pneumatic tire (radial tire, bias tire, etc.), a solid tire, etc. The use of the tire is preferably a passenger car tire, a high load tire, a motorcycle (motorcycle) tire, a studless tire, etc., a large tire such as a truck, a bus, etc. The use of the tire is more preferably suitable for use in a passenger car tire.

[0142] The shape, structure, size and material of the tire of the present invention are not particularly limited and are appropriately selected according to the purpose.

[0143] In the tire of the present invention, preferred members are a tread portion, a sidewall portion, a bead area portion, a belt portion, a carcass portion, a shoulder portion, etc.

[0144] The member of the tire is preferably a tire tread portion or a sidewall portion.

[0145] The tread portion has a tread pattern and is a portion that directly contacts the road surface, protects the carcass, and is the outer skin portion of the tire that prevents wear and trauma. Inside the tread portion, it refers to the cap tread that constitutes the grounding portion of the tire and / or the base tread disposed inside the cap tread.

[0146] The sidewall portion is a portion from below the shoulder portion to the bead portion in a pneumatic radial tire, protects the carcass, and is the portion where the most intense bending occurs during running.

[0147] The bead area part is the part that fixes both ends of the carcass cord and simultaneously fixes the tire to the rim. The bead has a structure in which high-carbon steel is bundled.

[0148] The belt part is a reinforcing belt stretched in the circumferential direction between the radial-structured tread and the carcass. The carcass is tightened strongly like the hoop of a barrel to increase the rigidity of the tread.

[0149] The carcass part is the part of the cord layer that forms the skeleton of the tire and plays a role in withstanding the load, impact, and inflation air pressure received by the tire.

[0150] The shoulder part is the part of the shoulder of the tire and serves to protect the carcass.

[0151] The tire of the present invention can be manufactured according to the conventional method in the field of tires. The gas filled in the tire is normal air or air with adjusted oxygen partial pressure; inert gases such as nitrogen, argon, and helium.

[0152] Since the rubber composition of the present invention contains 3-t-butyl-5-pyrazolone and / or its salt, the increase in the viscosity of the unvulcanized rubber composition is suppressed, and the processability (workability) is excellent.

[0153] Since the rubber composition of the present invention contains 3-t-butyl-5-pyrazolone and / or its salt, the tear strength of the vulcanized rubber composition is excellent.

[0154] Since the rubber composition of the present invention contains 3-t-butyl-5-pyrazolone and / or its salt, the tire manufactured using the vulcanized rubber composition has excellent handling stability.

[0155] The rubber composition of the present invention can be preferably used for various rubber members other than tire applications, such as anti-vibration rubber, seismic isolation rubber, and belts such as conveyor belts.

Examples

[0156] Hereinafter, the present invention will be specifically described by showing production examples and examples.

[0157] The examples are merely examples, and the present invention is not limited to the examples.

[0158] [1] Production of compounds a and c Production Example 1: Production of 3-t-butyl-5-pyrazolone (compound a) To a solution of 7.9 g of methyl 4,4-dimethyl-3-oxovalerate in 25 mL of methanol, 2.8 g of hydrazine monohydrate was added dropwise while cooling in a water bath. After heating under reflux for 24 hours, the solvent was distilled off to obtain a solid.

[0159] This solid was washed with 10 mL of diethyl ether and dried to obtain 5.6 g (yield 80%) of the target product.

[0160] 1 H-NMR (500 MHz, DMSO-d6, δ ppm): 11.14 (1H, br-s), 9.39 (1H, br-s), 5.22 (1H, s), 1.20 (9H, s) Melting point: 210 °C Production Example 2: Production of 3-phenyl-5-pyrazolone (compound c) To a solution of 25 g of ethyl benzoylacetate in 25 mL of ethanol, 6.5 g of hydrazine monohydrate was added dropwise while cooling in a water bath. After stirring at room temperature for 4 hours, the resulting white solid was filtered.

[0161] This solid was washed with 50 mL of a mixture of water:methanol = 1:1 (volume ratio) and dried to obtain 19 g (yield 90%) of the target product.

[0162] 1 H-NMR (500 MHz, DMSO-d6, δ ppm): 12.03 (1H, br), 9.69 (1H, br), 7.66 (2H, m), 7.39 (2H, m), 7.30 (1H, m), 5.88 (1H, s) Melting point: 236 °C [2] Production of rubber compositions of Examples and Comparative Examples Step (1) Each component described in step (1) of Table 1 below was mixed in its proportion (parts by mass) and kneaded with a Banbury mixer.

[0163] Step (2) Next, the mixture was cured until the temperature of the mixture reached 60°C or lower to produce an unvulcanized rubber composition.

[0164] Next, each component described in step (2) of Table 1 was added to the unvulcanized rubber composition in its proportion (parts by mass), and the mixture was kneaded while adjusting so that the maximum temperature of the mixture became 70°C or lower.

[0165] Vulcanization step The unvulcanized rubber composition was vulcanized by heating at 150°C for 25 minutes using a vulcanizing press to obtain a vulcanized rubber composition.

[0166] [3] Evaluation test [3-1] Processability test <Measurement of Mooney viscosity of unvulcanized rubber> The processability (Mooney viscosity) of the obtained unvulcanized rubber composition was measured based on JIS K6300-1 (Method for determining viscosity and scorch time by Mooney viscometer; ML1+4, 100°C).

[0167] The processability index of the unvulcanized rubber composition was expressed as an index when the Mooney viscosity value of the reference example (example without addition of additives) was set to 100, and the tear strength was calculated based on the following formula.

[0168] The smaller the value of the processability index, the better the processability of the unvulcanized rubber composition.

[0169] Formula: Processability index =(Mooney viscosity value of the unvulcanized rubber compositions of the examples and comparative examples) / (Mooney viscosity value of the unvulcanized rubber composition of the reference example)×100 The results of the processability index are shown in Table 1.

[0170] [3-2] Tear test <Measurement of tear strength of vulcanized rubber> The tear strength of the obtained vulcanized rubber composition was measured at room temperature under the condition of a tensile speed of 500 mm / min using a crescent-shaped test piece based on JIS K6252.

[0171] The tear strength index of the vulcanized rubber composition was expressed as an index when the tear strength value of the reference example (an example without the addition of additives) was set to 100, and the tear strength was calculated based on the following formula.

[0172] The larger the value of the tear strength index, the better the tear strength of the vulcanized rubber composition.

[0173] Formula: Tear strength index =(Tear strength of the vulcanized rubber compositions of the examples and comparative examples) / (Tear strength of the vulcanized rubber composition of the reference example) × 100 [3-3] Handling stability test <Measurement of 300% modulus (M300) of vulcanized rubber> The handling stability (300% modulus M300 of the vulcanized rubber) of the obtained vulcanized rubber composition was measured at room temperature for the modulus (M300) at 300% elongation using a No. 3 dumbbell-shaped test piece based on JIS K6251 (Vulcanized rubber and thermoplastic rubber - Method for determining tensile properties).

[0174] The handling stability index of the vulcanized rubber composition was expressed as an index when the M300 value of the reference example (an example without the addition of additives) was set to 100, and the tear strength was calculated based on the following formula.

[0175] The larger the value of the handling stability index, the better the handling stability of the tire manufactured using the vulcanized rubber composition.

[0176] Formula: Handling stability index =(M300 value of the vulcanized rubber compositions of the examples and comparative examples) / (M300 value of the vulcanized rubber composition of the reference example) × 100 The results of the handling stability index are shown in Table 1.

[0177]

Table 1

[0178] ※1: Natural rubber TSR-20 ※2: Compound a: 3-t-butyl-5-pyrazolone produced in Production Example 1 ※3: Compound b: 3-methyl-5-pyrazolone ※4: Compound c: 3-phenyl-5-pyrazolone produced in Production Example 2 ※5: Carbon black, N234 grade ※6: Antioxidant, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine ※7: Wax, manufactured by Rhein Chemie Rheinau, Antilux 111 ※8: Vulcanization accelerator, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) [4] Explanation of the results of the evaluation test [4-1] Processability The processability of the rubber composition containing 3-t-butyl-5-pyrazolone of Example 1 is as excellent as that of the rubber composition not containing conventional additives (Reference Example), and is superior to the rubber composition containing conventional 3-methyl-5-pyrazolone (Comparative Example 1).

[0179] The rubber composition of the present invention has a low value of the processability index of the unvulcanized rubber composition, suppresses the increase in viscosity of the unvulcanized rubber composition, and can be evaluated as having improved workability.

[0180] [4-2] Tear strength The tear strength of the rubber composition containing 3-t-butyl-5-pyrazolone of Example 1 is superior to that of the rubber composition not containing conventional additives (Reference Example), and is as excellent as the rubber composition containing conventional 3-methyl-5-pyrazolone (Comparative Example 1).

[0181] The rubber composition of the present invention has a high value of the tear strength index of the vulcanized rubber composition, and can be evaluated as having improved tear strength of the vulcanized rubber composition.

[0182] [4-3] Handling stability The handling stability of the rubber composition containing 3-t-butyl-5-pyrazolone of Example 1 is excellent compared to the rubber composition not containing conventional additives (reference example), and is also excellent compared to the rubber composition containing conventional 3-methyl-5-pyrazolone (Comparative Example 1).

[0183] For the rubber composition of the present invention, the value of the handling stability index of the vulcanized rubber composition is high, and it can be evaluated that the handling stability of the tire manufactured using the rubber composition of the present invention is improved.

Industrial Applicability

[0184] The rubber composition of the present invention contains a rubber component, and 3-t-butyl-5-pyrazolone and / or its salt. In the unvulcanized state, the increase in viscosity is suppressed, the workability is improved, and after vulcanization, the tear strength is improved.

[0185] In the tire manufactured using the rubber composition of the present invention, the handling stability is improved.

Claims

1. A rubber composition containing a rubber component, 3-t-butyl-5-pyrazolone and / or a salt thereof, wherein the rubber composition contains 0.2 parts by mass to 10 parts by mass of the 3-t-butyl-5-pyrazolone and / or the salt thereof with respect to 100 parts by mass of the rubber component.

2. The rubber composition according to Claim 1, wherein the rubber component is at least one rubber component selected from the group consisting of natural rubber, isoprene rubber, styrene-butadiene copolymer rubber, and butadiene rubber.

3. The rubber composition according to Claim 1 or 2, further containing carbon black and / or an inorganic filler.

4. The rubber composition according to Claim 3, wherein the rubber composition contains 20 parts by mass to 200 parts by mass of the carbon black and / or the inorganic filler with respect to 100 parts by mass of the rubber component.

5. A tire produced using the rubber composition according to any one of Claims 1 to 4.

6. A method for producing a rubber composition, comprising: (1) a step of mixing raw material components including a rubber component, 3-t-butyl-5-pyrazolone and / or a salt thereof, and carbon black and / or an inorganic filler; and (2) a step of mixing the mixture obtained in the step (1) and a vulcanizing agent, wherein in the step (1), the blending amount of the 3-t-butyl-5-pyrazolone and / or the salt thereof is 0.2 parts by mass to 10 parts by mass with respect to 100 parts by mass of the rubber component.

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