Rubber composition and tire

Abstract

The purpose of the present invention is to provide a rubber composition having, when being formed into a vulcanized rubber, further superior tear strength and low exothermic properties (low fuel consumption). This rubber composition contains: a rubber component; and a compound represented by formula (1) and / or a salt thereof.

Description

Rubber composition and tire

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

[0002] In recent years, automobiles have become much more powerful and powerful, and this has created a demand for high durability in tires that come into contact with the road. Among other things, high mechanical strength, more specifically high tear strength, is required, and rubber additives are needed to meet this demand.

[0003] Patent Documents 1 and 2 disclose techniques disclosed by the present applicant, which can impart low heat buildup and tear strength to a rubber component.

[0004] International Publication No. WO2020 / 045575A1 JP2021-134317

[0005] An object of the present invention is to provide a rubber composition which, when vulcanized, has superior tear strength and low heat buildup (fuel economy).

[0006] The present inventors have conducted extensive research to solve the above problems.

[0007] The present inventors have discovered that specific pyrazolone compounds can impart superior tear strength and low heat buildup to vulcanized rubber. These rubber compositions exhibit improved tear strength after vulcanization, and tires manufactured using these rubber compositions exhibit improved fuel economy.

[0008] The present inventors have further investigated based on the above findings and have completed the present invention. The present invention encompasses the following rubber composition and tire.

[0009] Item 1. A rubber composition comprising a rubber component and a compound represented by the following formula (1) and / or a salt thereof:

[0010] [In the formula, R 1 , and R 2 are the same or different and each represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or an acyl group, or R 1 and R 2 and together represent an alkylene group or an alkylidene group.3 represents a hydrogen atom, an alkyl group, or an aryl group. 4 , and R 5 are the same or different and each represents a hydrogen atom or an alkyl group, or R 4 , and R 5 and together represent an alkylene group or an alkylidene group, each of which may have one or more substituents.

[0011] Item 2. The compound represented by formula (1) is a compound represented by formula (1), wherein R 1 , and R 2 are the same or different and each represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, or R 1 and R 2 and together represent an alkylidene group, and R 3 represents a hydrogen atom, an alkyl group, or an aryl group, and R 4 , and R 5 are the same or different and each represents a hydrogen atom, an alkyl group, or R 4 and R 5 Item 2. The rubber composition according to item 1, wherein and together form an alkylidene group.

[0012] Item 3. The compound represented by formula (1) is 1 , and R 2 are the same or different and each represents a hydrogen atom, an alkyl group, an aryl group, or R 1 and R 2 and together represent an alkylidene group, and R 3 represents a hydrogen atom, an alkyl group, or an aryl group, and R 4 , and R 5 are the same or different and each represents a hydrogen atom, an alkyl group, or R 4 and R 5 Item 2. The rubber composition according to item 1, wherein and together form an alkylidene group.

[0013] Item 4. The rubber composition according to Item 1, wherein the compound represented by formula (1) and / or the salt thereof is at least one compound selected from the group consisting of 3-amino-5-pyrazolone, 3-isopropylamino-5-pyrazolone, 3-phenylamino-5-pyrazolone, 3-acetylamino-5-pyrazolone, 3-dodecylideneamino-5-pyrazolone, 3-amino-1-methyl-5-pyrazolone, 3-amino-1-phenyl-5-pyrazolone, 3-amino-4-methyl-5-pyrazolone, and 3-amino-4-phenylalkylidene-5-pyrazolone.

[0014] Item 5. The rubber composition according to item 1, wherein the compound represented by formula (1) and / or the salt thereof is at least one compound selected from the group consisting of 3-amino-5-pyrazolone, 3-isopropylamino-5-pyrazolone, 3-phenylamino-5-pyrazolone, 3-dodecylideneamino-5-pyrazolone, 3-amino-1-methyl-5-pyrazolone, 3-amino-1-phenyl-5-pyrazolone, 3-amino-4-methyl-5-pyrazolone, and 3-amino-4-phenylalkylidene-5-pyrazolone.

[0015] Item 6. The rubber composition according to Item 1, wherein the compound represented by formula (1) and / or the salt thereof is at least one compound selected from the group consisting of 3-amino-5-pyrazolone and 3-dodecylideneamino-5-pyrazolone and / or a salt thereof.

[0016] Item 7. The rubber composition according to Item 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.

[0017] Item 8. The rubber composition according to Item 1, wherein the rubber component is natural rubber.

[0018] Item 9. The rubber composition according to Item 1, further comprising carbon black and / or an inorganic filler.

[0019] Item 10. The rubber composition according to item 1, which is for use in tires.

[0020] Item 11. A tire made using the rubber composition according to any one of Items 1 to 10.

[0021] The rubber composition of the present invention is obtained by compounding a rubber component with a specific pyrazolone compound in combination, and exhibits superior tear strength and low heat buildup in the vulcanized rubber. These rubber compositions have improved tear strength after vulcanization, and tires manufactured using these rubber compositions have improved fuel economy.

[0022] The present invention can provide a rubber composition having superior tear strength and low heat buildup (fuel economy) in vulcanized rubber.

[0023] The present invention will be described in detail below.

[0024] The embodiments of the present invention are intended to provide a better understanding of the gist of the invention, and unless otherwise specified, do not limit the content of the invention.

[0025] In this specification, the terms "comprise" and "contain" are concepts that encompass all of "comprise," "consist essentially of," and "consist only of."

[0026] In this specification, when a numerical range is expressed as "A to B," it means "A or more, and B or less."

[0027] In this specification, the expressions parts, % and the like are generally used.

[0028] In this specification, unless otherwise specified, all parts by mass or % by mass (wt%) are used.

[0029] [1] Rubber Composition The rubber composition of the present invention contains a rubber component and a compound represented by the following formula (1) and / or a salt thereof.

[0030] In the formula, R 1 , and R 2 are the same or different and each represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or an acyl group, or R 1 and R 2and together represent an alkylene group or an alkylidene group.

[0031] In the formula, R 3 represents a hydrogen atom, an alkyl group, or an aryl group.

[0032] In the formula, R 4 , and R 5 are the same or different and each represents a hydrogen atom or an alkyl group, or R 4 and R 5 and together represent an alkylene group or an alkylidene group, each of which may have one or more substituents.

[0033] 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.

[0034] The rubber composition of the present invention preferably further contains carbon black and / or an inorganic filler.

[0035] The rubber composition of the present invention is obtained by compounding a rubber component with a specific pyrazolone compound in combination, and exhibits superior tear strength and low heat buildup in the vulcanized rubber. These rubber compositions have improved tear strength after vulcanization, and tires manufactured using these rubber compositions have improved fuel economy.

[0036] [1-1] Rubber Component The rubber composition of the present invention contains a rubber component.

[0037] 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, or other non-diene rubber.

[0038] The natural rubber (NR) is preferably natural rubber latex, technically graded rubber (TSR), smoked sheet rubber (RSS), gutta percha, eucommia-derived natural rubber, guayule-derived natural rubber, Russian dandelion-derived natural rubber, or the like.

[0039] Natural rubber (NR) includes modified natural rubber obtained by modifying the above-mentioned natural rubber. The modified natural rubber is preferably an epoxidized natural rubber, a methacrylic acid-modified natural rubber, a styrene-modified natural rubber, or the like.

[0040] The synthetic diene rubber is preferably a styrene-butadiene copolymer rubber (SBR), a butadiene rubber (BR), an isoprene rubber (IR), a nitrile rubber (NBR), a chloroprene rubber (CR), an ethylene-propylene-diene terpolymer rubber (EPDM), a styrene-isoprene-styrene triblock copolymer (SIS), a styrene-butadiene-styrene triblock copolymer (SBS), or the like.

[0041] The synthetic diene rubber includes a modified synthetic diene rubber obtained by modifying the synthetic diene rubber. The modified synthetic diene rubber preferably includes a diene rubber modified by a modification method such as main chain modification, single-end modification, or both-end modification. The modified functional group of the modified synthetic diene rubber is preferably an epoxy group, an amino group, an alkoxysilyl group, a hydroxyl group, or other functional group, and one or more of these functional groups may be contained in the modified synthetic diene rubber.

[0042] The method for producing the synthetic diene rubber is not particularly limited, and may be emulsion polymerization, solution polymerization, radical polymerization, anionic polymerization, cationic polymerization, etc. The glass transition temperature of the synthetic diene rubber is not particularly limited.

[0043] There are no particular limitations on the cis / trans / vinyl ratio of the double bonds in the natural rubber and synthetic diene rubber, and any ratio can be suitably used.

[0044] The number average molecular weight and molecular weight distribution of the diene rubber are not particularly limited, but 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.

[0045] The rubber component may be one of these rubber components or a mixture (blend) of two or more of them.

[0046] The rubber composition preferably contains, as a rubber component, at least one rubber component selected from the group consisting of the above-mentioned rubber components, more preferably at least one rubber component selected from the group consisting of NR, IR, SBR, and BR, and even more preferably at least one rubber component selected from the group consisting of NR, SBR, and BR.

[0047] The rubber composition particularly preferably contains NR as a rubber component. The rubber composition preferably contains 30 parts by mass or more of NR, more preferably 50 parts by mass or more of NR, and particularly preferably 90 parts by mass or more of NR, per 100 parts by mass of the rubber component.

[0048] In the rubber composition, there are no particular limitations on the blend ratio of the rubber components, but the blend ratio of the rubber components is preferably 50 to 100 parts by mass, more preferably 75 to 100 parts by mass, of NR, SBR, BR, or a mixture of two or more selected from these, per 100 parts by mass of the rubber components.

[0049] [1-2] Compound Represented by Formula (1) and / or Salt Thereof The rubber composition of the present invention contains a compound represented by the following formula (1) and / or a salt thereof.

[0050] In the formula, R 1 , and R 2 are the same or different and each represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or an acyl group, or R 1 and R 2 and together represent an alkylene group or an alkylidene group.

[0051] In the formula, R 3 represents a hydrogen atom, an alkyl group, or an aryl group.

[0052] In the formula, R 4 , and R 5 are the same or different and each represents a hydrogen atom or an alkyl group, or R 4 and R 5 and together represent an alkylene group or an alkylidene group.

[0053] In the formula, each of these groups may have one or more substituents.

[0054] The alkyl group is not particularly limited. Examples of the alkyl group include linear, branched, and cyclic alkyl groups. Specific examples of the alkyl group include linear or branched alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, and 1-ethylpropyl; linear or branched alkyl groups having 5 to 18 carbon atoms, such as n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, 3-methylpentyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, 5-propylnonyl, n-tridecyl, n-tetradecyl, n-pentadecyl, hexadecyl, heptadecyl, and octadecyl; and cyclic alkyl groups having 3 to 8 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl.

[0055] The aralkyl group is not particularly limited, and specific examples of the aralkyl group include benzyl, phenethyl, trityl, 1-naphthylmethyl, 2-(1-naphthyl)ethyl, and 2-(2-naphthyl)ethyl groups.

[0056] The aryl group is not particularly limited, and specific examples of the aryl group include phenyl, biphenyl, naphthyl, dihydroindenyl, and 9H-fluorenyl groups.

[0057] The acyl group is not particularly limited, and specifically includes linear or branched alkylcarbonyl groups having 1 to 4 carbon atoms, such as acetyl, propionyl, and pivaloyl groups, and arylcarbonyl groups, such as benzoyl and naphthoyl groups.

[0058] The alkylene group is not particularly limited. 1 and R 2 , or R 4 and R 5and form a ring structure together. Specific examples of the alkylene group include an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, and a heptamethylene group. The alkylene group may contain a nitrogen atom, an oxygen atom, or a sulfur atom, and may be connected via a phenylene group. Specific examples of such alkylene groups include -CHNHCH-, -CHNHCHCH-, -CHNHNHCH-, -CHCHNHCHCH-, -CHNHNHCHCH-, -CHNHCHNHCH-, -CHCHCHNHCHCHCH-, -CHOCHCH-, -CHCHOCHCH-, -CHSCHCH-, -CHCHSCHCH-, and alkylene groups having the following structures:

[0059] The alkylidene group is not particularly limited. 1 and R 2 , or R 4 and R 5 and form a double bond together. Specific examples of the alkylidene group include methylidene, ethylidene, propylidene, isopropylidene, butylidene, and 1,3-dimethylpropylidene groups.

[0060] In the formula, the alkyl group, aralkyl group, aryl group, acyl group, alkylene group, or alkylidene group may each have one or more substituents at any substitutable position.

[0061] The substituent is not particularly limited. The substituent is preferably a halogen atom, an amino group, an aminoalkyl group, an alkoxycarbonyl group, an acyl group, an acyloxy group, an amide group, a carboxyl group, a carboxyalkyl group, a formyl group, a nitrile group, a nitro group, an alkyl group, a hydroxyalkyl group, a hydroxyl group, an alkoxy group, an aryl group, an aryloxy group, a heterocyclic group, a thiol group, an alkylthio group, an arylthio group, or the like. The number of the substituents may be preferably 1 to 5, and more preferably 1 to 3.

[0062] Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and preferred examples include a chlorine atom, a bromine atom, and an iodine atom.

[0063] Specific examples of the amino group include an amino group represented by -NH2, as well as linear or branched monoalkylamino groups such as methylamino, ethylamino, n-propylamino, isopropylamino, n-butylamino, isobutylamino, s-butylamino, t-butylamino, 1-ethylpropylamino, n-pentylamino, neopentylamino, n-hexylamino, isohexylamino, and 3-methylpentylamino. The amino group is preferably a substituted amino group such as a dialkylamino group having two linear or branched alkyl groups, such as dimethylamino, ethylmethylamino, and diethylamino.

[0064] The aminoalkyl group is not particularly limited. Specific examples of the aminoalkyl group include aminomethyl, methylaminomethyl, ethylaminomethyl, dimethylaminomethyl, ethylmethylaminomethyl, diethylaminomethyl, 2-aminoethyl, 2-(methylamino)ethyl, 2-(ethylamino)ethyl, 2-(dimethylamino)ethyl, 2-(ethylmethylamino)ethyl, 2-(diethylamino)ethyl, 3-aminopropyl, 3-(methylamino)propyl, 3-(ethylamino)propyl, 3-(dimethylamino)propyl, 3-(ethylmethylamino)propyl, and 3-(diethylamino)propyl groups, as well as monoalkyl-substituted aminoalkyl groups and dialkyl-substituted aminoalkyl groups.

[0065] The alkoxycarbonyl group is not particularly limited, and specific examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.

[0066] The acyl group is not particularly limited, and specific examples thereof include linear or branched alkylcarbonyl groups having 1 to 4 carbon atoms, such as acetyl, propionyl, and pivaloyl groups.

[0067] The acyloxy group is not particularly limited, and specific examples of the acyloxy group include acetyloxy, propionyloxy, and n-butyryloxy groups.

[0068] The amide group is not particularly limited. Specific examples of the amide group include carboxylic acid amide groups such as acetamide and benzamide groups, thioamide groups such as thioacetamide and thiobenzamide groups, and N-substituted amide groups such as N-methylacetamide and N-benzylacetamide groups.

[0069] The carboxyalkyl group is not particularly limited, and specific examples of the carboxyalkyl group include carboxymethyl, carboxyethyl, carboxy-n-propyl, carboxy-n-butyl, carboxy-n-pentyl, and carboxy-n-hexyl groups.

[0070] The hydroxyalkyl group is not particularly limited, and specific examples of the hydroxyalkyl group include hydroxymethyl, hydroxyethyl, hydroxy-n-propyl, and hydroxy-n-butyl groups.

[0071] The alkoxy group is not particularly limited. The alkoxy group may be a linear, branched, or cyclic alkoxy group. Specific examples of the alkoxy group include linear or branched alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, t-butoxy, n-pentyloxy, neopentyloxy, and n-hexyloxy groups, and cyclic alkoxy groups such as cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, and cyclooctyloxy groups.

[0072] The aryloxy group is not particularly limited, and specific examples of the aryloxy group include phenoxy, biphenyloxy, and naphthoxy groups.

[0073] The heterocyclic group is not particularly limited. Specific examples of the heterocyclic group include 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyrazinyl, 2-pyrimidyl, 4-pyrimidyl, 5-pyrimidyl, 3-pyridazyl, 4-pyridazyl, 4-(1,2,3-triazyl), 5-(1,2,3-triazyl), 2-(1,3,5-triazyl), 3-(1,2,4-triazyl), 5-(1,2,4-triazyl), 6-(1,2,4-triazyl), 2-quinolyl, 3-quinolyl, 4-quinolyl, 5-quinolyl, 6-quinolyl, 7-quinolyl, 8-quinolyl, 1-isoquinolyl, and 3-isoquinolyl. , 4-isoquinolyl, 5-isoquinolyl, 6-isoquinolyl, 7-isoquinolyl, 8-isoquinolyl, 2-quinoxalyl, 3-quinoxalyl, 5-quinoxalyl, 6-quinoxalyl, 7-quinoxalyl, 8-quinoxalyl, 3-cinnolyl, 4-cinnolyl, 5-cinnolyl, 6-cinnolyl, 7-cinnolyl, 8-cinnolyl, 2-quinazolyl, 4-quinazolyl, 5-quinazolyl, 6-quinazolyl, 7-quinazolyl, 8-quinazolyl, 1-phthalazyl, 4-phthalazyl, 5-phthalazyl, 6-phthalazyl, 7-phthalazyl, 8-phthalazyl, 1-Tetrahydroquinolyl, 2-tetrahydroquinolyl, 3-tetrahydroquinolyl, 4-tetrahydroquinolyl, 5-tetrahydroquinolyl, 6-tetrahydroquinolyl, 7-tetrahydroquinolyl, 8-tetrahydroquinolyl, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 2-furyl, 3-furyl, 2-thienyl, 3-thienyl, 1-imidazolyl, 2-imidazolyl, 4-imidazolyl, 5-imidazolyl, 1-pyrazolyl, 3-pyrazolyl, 4-pyrazolyl, 5-pyrazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl thiadiazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 3-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl, 4-(1,2,3-thiadiazolyl), 5-(1,2,3-thiadiazolyl), 3-(1,2,5-thiadiazolyl), 2-(1,3,4-thiadiazolyl), 4-(1,2,3-oxadiazolyl), 5-(1,2,3-oxadiazolyl), 3-(1,2,4-oxadiazolyl), 5-(1,2,4-oxadiazolyl), 3-(1,2,5-oxadiazolyl), 2-(1,3,4-oxadiazolyl), 1-(1,2,3-triazolyl), 4-(1,2,3-triazolyl), 5-(1,2,3-triazolyl), 1-(1,2,4-triazolyl), 3-(1,2,4-triazolyl), 5-(1,2,4-triazolyl), 1-tetrazolyl, 5-tetrazolyl, 1-indolyl, 2-indolyl, 3-indolyl, 4-indolyl, 5-indolyl, 6-indolyl, 7-indolyl, 1-isoindolyl, 2-isoindolyl, 3-isoindolyl, 4-isoindolyl , 5-Isoindolyl, 6-Isoindolyl, 7-Isoindolyl, 1-Benzimidazolyl, 2-Benzimidazolyl, 4-Benzimidazolyl, 5-Benzimidazolyl, 6-Benzimidazolyl, 7-Benzimidazolyl, 2-Benzofuranyl, 3-Benzofuranyl, 4-Benzofuranyl, 5-Benzofuranyl, 6-Benzofuranyl, 7-Benzofuranyl, 1-Isobenzofuranyl, 3-Isobenzofuranyl, 4-Isobenzofuranyl, 5-Isobenzofuranyl, 6-Isobenzofuranyl, 7-Isobenzofuranyl, 2-Benzothienyl, 3-Benzofuranyl Inzothienyl, 4-benzothienyl, 5-benzothienyl, 6-benzothienyl, 7-benzothienyl, 2-benzoxazolyl, 4-benzoxazolyl, 5-benzoxazolyl, 6-benzoxazolyl, 7-benzoxazolyl, 2-benzothiazolyl, 4-benzothiazolyl, 5-benzothiazolyl, 6-benzothiazolyl, 7-benzothiazolyl, 1-indazolyl, 3-indazolyl, 4-indazolyl, 5-indazolyl, 6-indazolyl, 7-indazolyl, 2-morpholyl, 3-morpholyl, 4-morpholyl, 1-piperazolyl Examples of such groups include aryl, 2-piperazyl, 1-piperidyl, 2-piperidyl, 3-piperidyl, 4-piperidyl, 2-tetrahydropyranyl, 3-tetrahydropyranyl, 4-tetrahydropyranyl, 2-tetrahydrothiopyranyl, 3-tetrahydrothiopyranyl, 4-tetrahydrothiopyranyl, 1-pyrrolidyl, 2-pyrrolidyl, 3-pyrrolidyl, furanyl, 2-tetrahydrofuranyl, 3-tetrahydrofuranyl, 2-tetrahydrothienyl, 3-tetrahydrothienyl, and 5-methyl-3-oxo-2,3-dihydro-1H-pyrazol-4-yl groups.

[0074] The compound represented by formula (1) and / or a salt thereof may be, among others, R 1 , and R 2 are the same or different and each represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, or R 1 and R 2 and together form an alkylidene group are preferred.

[0075] The compound represented by formula (1) and / or a salt thereof may be, among others, R 1 , and R 2 A compound in which both are hydrogen atoms is more preferred.

[0076] The compound represented by formula (1) and / or a salt thereof may be, among others, R 1 , and R 2 is a hydrogen atom, and R 1 , and R 2 More preferred are compounds in which one of the groups is an alkyl group or an aryl group.

[0077] The compound represented by formula (1) and / or a salt thereof may be, among others, R 1 and R 2 More preferred are compounds in which and together represent an alkylidene group.

[0078] The compound represented by formula (1) and / or a salt thereof may be, among others, R 1 , and R 2 Particularly preferred are compounds in which both are hydrogen atoms.

[0079] The compound represented by formula (1) and / or a salt thereof may be, among others, R 1 , and R 2 is a hydrogen atom, and R 1 , and R 2 Particularly preferred are compounds in which one of the groups is a linear or branched alkyl group having 1 to 4 carbon atoms, a phenyl group, or an acetyl group.

[0080] The compound represented by formula (1) and / or a salt thereof may be, among others, R 1 and R 2 Particularly preferred are compounds in which and together represent an alkylidene group.

[0081] The compound represented by formula (1) and / or a salt thereof may be, among others, R 3 is preferably a hydrogen atom, a linear or branched alkyl group, or an aryl group (phenyl group or naphthyl group).

[0082] The compound represented by formula (1) and / or a salt thereof may be, among others, R 3 Particularly preferred are compounds in which represents a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a phenyl group.

[0083] The compound represented by formula (1) and / or a salt thereof may be, among others, R 4 , and R 5 are the same or different and each represents a hydrogen atom or an alkyl group, or R ４ and R ５ and together form an alkylidene group are preferred.

[0084] The compound represented by formula (1) and / or a salt thereof may be, among others, R 4 , and R 5 A compound in which both are hydrogen atoms is more preferred.

[0085] The compound represented by formula (1) and / or a salt thereof may be, among others, R 4 , and R 5 is a hydrogen atom, and R 4 , and R 5 More preferred is a compound in which one of the groups is an alkyl group.

[0086] The compound represented by formula (1) and / or a salt thereof may be, among others, R 4 and R 5 More preferred are compounds in which and together represent an alkylidene group.

[0087] The compound represented by formula (1) and / or a salt thereof may be, among others, R 4 , and R 5 Particularly preferred are compounds in which both are hydrogen atoms.

[0088] The compound represented by formula (1) and / or a salt thereof may be, among others, R 4 , and R 5 is a hydrogen atom, and R 4 , and R5 Particularly preferred are compounds in which one of the groups is a linear or branched alkyl group having 1 to 4 carbon atoms.

[0089] The compound represented by formula (1) and / or a salt thereof may be, among others, R 4 and R 5 Particularly preferred are compounds in which and together represent an alkylidene group.

[0090] The compound represented by formula (1) and / or a salt thereof may be, among others, R 1 , and R 2 are the same or different and each represents a hydrogen atom, an alkyl group, an aryl group, an acyl group, or R 1 and R 2 and together represent an alkylidene group, and R 3 is a hydrogen atom, an alkyl group, or an aryl group, and R 4 , and R 5 are the same or different and each represents a hydrogen atom or an alkyl group, or R 4 and R 5 and together form an alkylidene group are preferred.

[0091] The compound represented by formula (1) and / or a salt thereof may be, among others, R 1 , and R 2 are the same or different and each represents a hydrogen atom, an alkyl group, an aryl group, or R 1 and R 2 and together represent an alkylidene group, and R 3 represents a hydrogen atom, an alkyl group, or an aryl group, and R 4 , and R 5 are the same or different and each represents a hydrogen atom, an alkyl group, or R 4 and R 5 More preferred are compounds in which and together represent an alkylidene group.

[0092] The compound represented by formula (1) and / or a salt thereof may be, among others, R 1 , and R 2 are both hydrogen atoms, R 1 , and R 2 is a hydrogen atom, and R 1 , and R 2one of which is a linear or branched alkyl group having 1 to 4 carbon atoms, a phenyl group, or R 1 and R 2 and together represent an alkylidene group, and R 3 is a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a phenyl group, and R 4 , and 5 2 are both hydrogen atoms, R 4 , and R 5 is a hydrogen atom, and R 4 , and R 5 one of which is a linear or branched alkyl group having 1 to 4 carbon atoms, or R 4 and R 5 Particularly preferred are compounds in which and together represent an alkylidene group.

[0093] Specifically, among the compounds represented by formula (1) and / or salts thereof, 3-amino-5-pyrazolone, 3-isopropylamino-5-pyrazolone, 3-phenylamino-5-pyrazolone, 3-acetylamino-5-pyrazolone, 3-dodecylideneamino-5-pyrazolone, 3-amino-1-methyl-5-pyrazolone, 3-amino-1-phenyl-5-pyrazolone, 3-amino-4-methyl-5-pyrazolone, and 3-amino-4-phenylalkylidene-5-pyrazolone are preferred.

[0094] Among the compounds represented by formula (1) and / or salts thereof, 3-amino-5-pyrazolone, 3-isopropylamino-5-pyrazolone, 3-phenylamino-5-pyrazolone, 3-dodecylideneamino-5-pyrazolone, 3-amino-1-methyl-5-pyrazolone, 3-amino-1-phenyl-5-pyrazolone, 3-amino-4-methyl-5-pyrazolone, and 3-amino-4-phenylalkylidene-5-pyrazolone are more preferred.

[0095] Of the compounds represented by formula (1) and / or salts thereof, 3-amino-5-pyrazolone and 3-dodecylideneamino-5-pyrazolone are more preferred.

[0096] The compound of formula (1) can occur in tautomers. When tautomerization is possible (for example, in solution), a chemical equilibrium of the tautomers can be reached.

[0097] The compound represented by formula (1) and / or its salt and its tautomer are in an equilibrium state in which both isomers coexist. The compound represented by formula (1) and / or its salt included in the present invention encompasses all of the tautomeric forms, unless otherwise specified.

[0098] The compound represented by formula (1) may be in the form of a salt, and the salt of the compound represented by formula (1) is not particularly limited and includes all kinds of salts.

[0099] Examples of such salts include inorganic acid salts such as hydrochloride, sulfate, and nitrate; organic acid salts such as acetate and methanesulfonate; alkali metal salts such as sodium salt and potassium salt; alkaline earth metal salts such as magnesium salt and calcium salt; and ammonium salts such as dimethylammonium and triethylammonium.

[0100] The rubber composition of the present invention contains, relative to 100 parts by mass of the rubber component, preferably 0.1 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, even more preferably 0.2 to 10 parts by mass, and particularly preferably 0.5 to 5 parts by mass of the compound represented by formula (1) and / or its salt.

[0101] The rubber composition of the present invention is obtained by compounding a rubber component with a specific pyrazolone compound in combination, and exhibits superior tear strength and low heat buildup in the vulcanized rubber. These rubber compositions have improved tear strength after vulcanization, and tires manufactured using these rubber compositions have improved fuel economy.

[0102] [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.

[0103] Carbon Black As used herein, inorganic filler does not include carbon black.

[0104] Carbon black is used to improve the reinforcing properties of rubber.

[0105] The carbon black is not particularly limited, and examples of the carbon black include commercially available carbon black and carbon-silica dual phase filler.

[0106] By including carbon black in the rubber component, it is possible to lower the electrical resistance of the rubber, thereby suppressing static electricity and improving the strength of the rubber.

[0107] The carbon black is preferably a high, medium or low structure SAF, ISAF, IISAF, N110, N134, N220, N234, N330, N339, N375, N550, HAF, FEF, GPF, SRF grade carbon black, etc. The carbon black is preferably a SAF, ISAF, IISAF, N134, N234, N330, N339, N375, HAF, FEF grade carbon black.

[0108] The DBP absorption range of the carbon black is preferably 60 cm 3 / 100g~200cm 3 / 100g, more preferably 70cm 3 / 100g~180cm 3 / 100g, particularly preferably 80cm 3 / 100g~160cm 3 / 100g.

[0109] The nitrogen adsorption specific surface area (N2SA) of carbon black is measured in accordance with JIS K6217-2:2001. The nitrogen adsorption specific surface area of ​​carbon black is preferably in the range of 30 m 2 / g~200m 2 / g, more preferably 40m 2 / g~180m 2 / g, and particularly preferably 50m 2 / g~160m 2 / g.

[0110] Inorganic Filler There are no particular limitations on the inorganic filler, and inorganic compounds that are commonly used in the rubber industry can be used.

[0111] The inorganic compound is preferably silica.

[0112] The inorganic compound is preferably alumina (Al2O3) such as γ-alumina or α-alumina.

[0113] The inorganic compound is preferably alumina monohydrate (Al2O3.H2O) such as boehmite or diaspore.

[0114] The inorganic compound is preferably aluminum hydroxide [Al(OH)3] such as gibbsite or bayerite.

[0115] 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], aluminum magnesium 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.), aluminum calcium silicate (Al2O3·CaO·2SiO2, etc.), magnesium calcium silicate (CaMgSiO4), calcium carbonate (CaCO3), zirconium oxide (ZrO2), zirconium hydroxide [ZrO(OH)2·nH2O], zirconium carbonate [Zr(CO3)2], zinc acrylate, zinc methacrylate, etc.

[0116] The inorganic compounds are preferably crystalline aluminosilicates containing hydrogen, alkali metals, or alkaline earth metals to compensate for the charge, such as various zeolites.

[0117] The inorganic filler may preferably be an inorganic compound whose surface has been organically treated in order to improve its affinity with the rubber component.

[0118] The inorganic filler is preferably silica, from the viewpoint of being able to impart rubber strength.

[0119] The silica is preferably wet silica, dry silica, or colloidal silica, and more preferably wet silica.

[0120] Preferably, the silica may be surface-treated with an organic agent in order to improve its affinity with the rubber component.

[0121] The BET specific surface area of ​​silica is measured in accordance with ISO 5794 / 1. The range of the BET specific surface area of ​​silica is preferably 40 m 2 / g~350m 2 / g. Silica having a BET specific surface area in 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~300m 2 / g, more preferably 100m 2 / g~270m 2 / g, and particularly preferably 110m 2 / g~270m 2 / g.

[0122] Commercially available silica products include, for example, the product name "HD165MP" (BET specific surface area = 165 m) manufactured by Quechen Silicon Chemical Co., Ltd. 2 / g), "HD115MP" (BET specific surface area = 115m 2 / g), "HD200MP" (BET specific surface area = 200m 2 / g), "HD250MP" (BET specific surface area = 250m 2 / g), and Tosoh Silica Corporation's product name "Nipsil AQ" (BET specific surface area = 205 m 2 / g), "Nipsil KQ" (BET specific surface area = 240 m 2 / g), and Ultrasil VN3 (BET specific surface area = 175 m) manufactured by Degussa. 2 / g), etc.

[0123] The carbon black and / or inorganic filler may be used alone or in combination (blended) of two or more kinds.

[0124] Amount of Carbon Black and / or Inorganic Filler The rubber composition of the present invention preferably contains 20 to 200 parts by mass of carbon black and / or inorganic filler per 100 parts by mass of the rubber component, more preferably 30 to 130 parts by mass, and even more preferably 35 to 110 parts by mass.

[0125] The amount of carbon black and / or inorganic filler added is preferably 20 parts by mass or more from the viewpoint of improving the reinforcing properties of the rubber composition, and is preferably 200 parts by mass or less from the viewpoint of improving the tear strength.

[0126] When both carbon black and an inorganic filler are blended, the total amount of both components may be adjusted appropriately so as to fall within the above range.

[0127] The amount of carbon black mixed per 100 parts by mass of the rubber component is preferably 2 parts by mass to 200 parts by mass, more preferably 30 parts by mass to 130 parts by mass, and even more preferably 35 parts by mass to 100 parts by mass.

[0128] The amount of carbon black blended is preferably 2 parts by mass or more from the viewpoint of ensuring anti-static properties and rubber strength properties, and is preferably 200 parts by mass or less from the viewpoint of improving tear strength.

[0129] The blending amount of the inorganic filler is preferably 2 parts by mass to 200 parts by mass, more preferably 30 parts by mass to 130 parts by mass, and even more preferably 35 parts by mass to 100 parts by mass, per 100 parts by mass of the rubber component.

[0130] 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 even more preferably 35 parts by mass to 100 parts by mass, per 100 parts by mass of the rubber component.

[0131] [1-4] Other Compounding Agents The rubber composition of the present invention may contain, in addition to the rubber component, the compound represented by formula (1) and / or its salt, and, as necessary, carbon black and / or an inorganic filler, other compounding agents commonly used in the rubber industry, as appropriate.

[0132] Examples of compounding agents include antioxidants, antiozonants, softeners, processing aids, waxes, resins, foaming agents, oils, zinc oxide (ZnO), stearic acid, vulcanization accelerators, vulcanization retarders, and vulcanizing agents (sulfur, etc.).

[0133] Silane Coupling Agents, etc. When the rubber composition of the present invention contains an inorganic filler such as carbon black or silica, a silane coupling agent, titanate coupling agent, aluminate coupling agent, zirconate coupling agent, etc. may be compounded into the rubber composition for the purpose of increasing the reinforcing properties of the rubber composition by means of the carbon black, silica, etc., and for the purpose of increasing the tear strength and abrasion resistance of the rubber composition.

[0134] The silane coupling agent is preferably a sulfide-based, polysulfide-based, thioester-based, thiol-based, olefin-based, epoxy-based, amino-based, alkyl-based or other silane coupling agent.

[0135] The titanate coupling agent is preferably an alkoxide-based, chelate-based, or acylate-based titanate coupling agent.

[0136] The zirconate coupling agent is preferably an alkoxide-based, chelate-based, or acylate-based zirconate coupling agent.

[0137] The silane coupling agent, titanate coupling agent, aluminate coupling agent, or zirconate coupling agent may be used alone or in combination (blended) of two or more.

[0138] In the rubber composition of the present invention, the blending amount of the silane coupling agent, titanate coupling agent, aluminate coupling agent, or zirconate coupling agent is preferably 0.1 to 20 parts by mass, more preferably 3 to 15 parts by mass, per 100 parts by mass of carbon black and / or inorganic filler. By setting the blending amount of the silane coupling agent, titanate coupling agent, aluminate coupling agent, or zirconate coupling agent to 0.1 part by mass or more per 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, and by setting the blending amount to 20 parts by mass or less, the cost of the rubber composition can be reduced, improving economy.

[0139] The rubber composition of the present invention is obtained by compounding a rubber component with a specific pyrazolone compound in combination, and exhibits superior tear strength and low heat buildup in the vulcanized rubber. These rubber compositions have improved tear strength after vulcanization, and tires manufactured using these rubber compositions have improved fuel economy.

[0140] [2] Manufacturing Method of Rubber Composition The manufacturing method of the rubber composition of the present invention includes: (1) a step of mixing raw material components including a rubber component, a compound represented by formula (1) and / or a salt thereof, and, as necessary, carbon black and / or an inorganic filler; and (2) a step of mixing the mixture obtained in the step (1) with a vulcanizing agent (sulfur, etc.).

[0141] Step (1) is a step of kneading raw material components including a rubber component, a compound represented by formula (1) and / or a salt thereof, and, as necessary, carbon black and / or an inorganic filler, and is a step prior to compounding with a vulcanizing agent.

[0142] The kneading method in step (1) is, for example, a method of kneading a composition containing a rubber component, a compound represented by formula (1) and / or a salt thereof, and, if necessary, raw material components such as carbon black and / or an inorganic filler. In step (1), the above-mentioned other compounding agents can also be compounded, if necessary.

[0143] The kneading method may involve kneading all of the components at once, or depending on the purpose of viscosity adjustment or the like, the components may be added in portions and kneaded.

[0144] Alternatively, the kneading method may involve kneading the rubber component with carbon black and / or inorganic filler, and then adding the compound represented by formula (1) and / or its salt and kneading them together, or kneading the rubber component with the compound represented by formula (1) and / or its salt and then adding the carbon black and / or inorganic filler and kneading them together. In the kneading method, the kneading operation may be repeated to uniformly disperse the components.

[0145] The upper limit of the kneading temperature of the rubber composition in step (1) is preferably 100°C to 190°C, more preferably 110°C to 175°C, and even more preferably 120°C to 170°C.

[0146] The kneading time in step (1) is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 1 minute to 8 minutes.

[0147] Two-Stage Kneading in Step (1) Another kneading method for Step (1) may be a two-stage kneading method including: Step (1-1) a step of kneading a rubber component with the compound represented by Formula (1) and / or a salt thereof; and Step (1-2) a step of kneading the mixture obtained in Step (1-1) with raw material components containing carbon black and / or an inorganic filler.

[0148] The kneading temperature in step (1-1) is preferably 60° C. to 190° C., more preferably 70° C. to 160° C., and even more preferably 80° C. to 150° C. By adjusting the kneading temperature to 60° C. to 190° C., the reaction proceeds smoothly and deterioration of the rubber can be suppressed.

[0149] The kneading time in step (1-1) is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 60 seconds to 7 minutes. By adjusting the kneading time to 10 seconds to 20 minutes, the reaction proceeds smoothly and productivity can be improved.

[0150] The upper limit of the kneading temperature in step (1-2) of the mixture is preferably 100°C to 190°C, more preferably 130°C to 175°C, and even more preferably 110°C to 170°C.

[0151] The kneading time in step (1-2) is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 1 minute to 8 minutes.

[0152] In the step (1) and the step (1-1), the compound represented by formula (1) and / or its salt is mixed in an amount of preferably 0.1 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and even more preferably 0.2 to 10 parts by mass, per 100 parts by mass of the rubber component.

[0153] When proceeding from step (1) to step (2), the temperature is preferably lowered by 30°C or more from the temperature after the end of step (1) before proceeding to the next step (2).

[0154] Step (2) Step (2) is the final step of kneading, in which the mixture obtained in step (1) is mixed with a vulcanizing agent (sulfur, etc.).

[0155] In step (2), a vulcanization accelerator or the like can be further added as required.

[0156] 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 even more preferably 90°C to 120°C.

[0157] The mixing (or kneading) time in step (2) is preferably 10 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 60 seconds to 5 minutes.

[0158] Addition of Other Compounding Agents In the method for producing the rubber composition of the present invention, various compounding agents to be compounded in the rubber composition, such as stearic acid, zinc oxide, a vulcanization accelerator, and an antioxidant, can be added as needed in step (1) (step (1-1) and step (1-2)) and step (2).

[0159] The other compounding ingredients may be added in either step (1) and / or step (2), or may be added separately in steps (1) and (2).

[0160] The rubber composition of the present invention is obtained by compounding a rubber component with a specific pyrazolone compound in combination, and exhibits superior tear strength and low heat buildup in the vulcanized rubber. These rubber compositions have improved tear strength after vulcanization, and tires manufactured using these rubber compositions have improved fuel economy.

[0161] [3] Tire The rubber composition of the present invention is preferably used for a tire. The present invention includes a tire produced using the rubber composition of the present invention.

[0162] The rubber composition of the present invention is mixed or kneaded using a Banbury mixer, a roll, an intensive mixer, a kneader, a single-screw extruder, a twin-screw extruder, or the like.

[0163] The rubber composition is then extruded and processed in an extrusion process, and molded into, for example, a tread component or a sidewall component.

[0164] The rubber composition is then applied and molded in a conventional manner on a tire building machine to form a green tire.

[0165] This green tire is heated and pressurized in a vulcanizer to obtain a tire.

[0166] Tires and Other Applications The tires of the present invention are made using the rubber composition of the present invention.

[0167] The tire is preferably a pneumatic tire (radial tire, bias tire, etc.), a solid tire, etc. The tire is preferably used as a passenger car tire, a heavy-duty tire, a motorcycle tire, a studless tire, a large tire for trucks, buses, etc. The tire is more preferably used as a passenger car tire.

[0168] The shape, structure, size and material of the tire of the present invention are not particularly limited and may be appropriately selected depending on the purpose.

[0169] In the tire of the present invention, preferred components are the tread portion, sidewall portion, bead area portion, belt portion, carcass portion, shoulder portion, and the like.

[0170] The tire component is preferably a tire tread portion or a sidewall portion.

[0171] The tread portion has a tread pattern and is the outer shell portion of the tire that directly contacts the road surface, protecting the carcass and preventing wear and damage. Within the tread portion, it refers to the cap tread that constitutes the tire's contact patch and / or the base tread disposed inside the cap tread. By applying the rubber composition of the present invention to the tread portion, this rubber composition contains a combination of a rubber component and a specific pyrazolone compound, and the tread portion exhibits the effects of superior tear strength and low heat buildup.

[0172] The sidewall portion is the portion of a pneumatic radial tire extending from below the shoulder portion to the bead portion, and protects the carcass and is the portion that is most subject to bending during running. By applying the rubber composition of the present invention to the sidewall portion, which contains a rubber component and a specific pyrazolone compound in combination, the sidewall portion exhibits superior tear strength and low heat buildup.

[0173] The bead area is the portion that secures both ends of the carcass cord and at the same time secures the tire to the rim. The bead is made of bundles of high-carbon steel. By applying the rubber composition of the present invention to the bead area, which contains a rubber component and a specific pyrazolone compound in combination, the bead area exhibits superior tear strength and low heat buildup.

[0174] The belt portion is a reinforcing band stretched circumferentially between the radial tread and carcass. It tightens the carcass like a tub hoop, increasing the rigidity of the tread. By applying the rubber composition of the present invention to the belt portion, which contains a rubber component in combination with a specific pyrazolone compound, the belt portion exhibits superior tear strength and low heat buildup.

[0175] The carcass is the cord layer that forms the skeleton of the tire and serves to withstand the load, impact, and inflation pressure that the tire receives. By applying the rubber composition of the present invention to the carcass, which contains a rubber component and a specific pyrazolone compound in combination, the carcass exhibits superior tear strength and low heat buildup.

[0176] The shoulder portion of the tire serves to protect the carcass. By applying the rubber composition of the present invention to the shoulder portion, which contains a rubber component and a specific pyrazolone compound in combination, the shoulder portion exhibits superior tear strength and low heat buildup.

[0177] The tire of the present invention can be manufactured according to a conventional method in the field of tires. The gas to be filled in the tire is normal air or air with an adjusted partial pressure of oxygen; or an inert gas such as nitrogen, argon, or helium.

[0178] The rubber composition of the present invention can be used not only for tires but also for various rubber members, preferably for vibration-proof rubber, seismic isolation rubber, and belts such as conveyor belts.

[0179] The rubber composition of the present invention is obtained by compounding a rubber component with a specific pyrazolone compound in combination, and exhibits superior tear strength and low heat buildup in the vulcanized rubber. These rubber compositions have improved tear strength after vulcanization, and tires manufactured using these rubber compositions have improved fuel economy.

[0180] The present invention will be specifically described below by showing Production Examples and Examples, which are merely illustrative and are not intended to limit the scope of the present invention.

[0181] [1] Production of Rubber Compositions of Examples and Comparative Examples Step (1) Each component shown in step (1) in Table 1 below was mixed in the ratio (parts by mass) and kneaded in a Banbury mixer.

[0182] Step (2) Next, the mixture was cured until the temperature of the mixture reached 60°C or less, to produce an unvulcanized rubber composition.

[0183] Next, each component shown in step (2) in Table 1 was added to the unvulcanized rubber composition in the proportion (parts by mass), and the mixture was kneaded while adjusting the maximum temperature of the mixture to 70°C or less.

[0184] Vulcanization Step The unvulcanized rubber composition was vulcanized by heating at 150°C for 25 minutes using a vulcanization press to obtain a vulcanized rubber composition.

[0185] [2] Evaluation Test [2-1] Tear Test: Measurement of Tear Strength of Vulcanized Rubber The "tear strength" of the obtained vulcanized rubber composition was measured using a crescent-type test piece at room temperature and at a tensile speed of 500 mm / min in accordance with JIS K6252.

[0186] The tear strength index of the vulcanized rubber composition was expressed as an index when the tear strength value of Comparative Example 1 (an example containing no compound represented by formula (1)) was set to 100, and the tear strength was calculated based on the following formula.

[0187] Examples 1 and 2 are examples in which the compound represented by formula (1) was blended.

[0188] The larger the tear strength index value, the better the tear strength of the vulcanized rubber composition. Formula: Tear strength index = (tear strength of vulcanized rubber compositions of Examples 1 and 2) / (tear strength of vulcanized rubber composition of Comparative Example 1) × 100

[0189] [2-2] Low heat buildup test: Measurement of Tan δ value The "Tan δ value" of the obtained vulcanized rubber composition was measured using a viscoelasticity measuring device (manufactured by Metravib) under the conditions of a temperature of 40°C, a dynamic strain of 5%, and a frequency of 15 Hz.

[0190] The low heat buildup index of the vulcanized rubber composition was expressed as an index when the Tan δ value of Comparative Example 1 (an example containing no compound represented by formula (1)) was set to 100, and the tear strength was calculated based on the following formula.

[0191] Examples 1 and 2 are examples in which the compound represented by formula (1) was blended.

[0192] The smaller the low heat buildup index value, the better the low heat buildup property of the vulcanized rubber composition and the smaller the hysteresis loss. Formula: Low heat buildup index = (Tan δ values ​​of the vulcanized rubber compositions of Examples 1 and 2) / (Tan δ value of the vulcanized rubber composition of Comparative Example 1) × 100

[0193] The results of the tear strength index and handling stability index are shown in Table 1.

[0194]

[0195] *1: Natural rubber TSR-20 *2: Carbon black, N234 grade *3: Antioxidant, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine *4: Wax, Rhein Chemie Rheinau, Antilux 111 *5: Vulcanization accelerator, N-cyclohexyl-2-benzothiazolylsulfenamide (CBS) *6: Compound A, 3-amino-5-pyrazolone *7: Compound B, 3-dodecylideneamino-5-pyrazolone

[0196] [3] Explanation of the results of the evaluation test [3-1] Tear strength The tear strength of the rubber compositions containing the compound represented by formula (1) in Examples 1 and 2 is superior to that of the rubber composition of Comparative Example 1 (prior art).

[0197] The rubber composition of the present invention has a high tear strength index after vulcanization, and it can be evaluated that the tear strength of the rubber composition after vulcanization is improved.

[0198] [4-2] Low Heat Buildup The low heat buildup of the rubber compositions containing the compound represented by formula (1) of Examples 1 and 2 is superior to that of the rubber composition of Comparative Example 1 (prior art).

[0199] The rubber composition of the present invention has a low low heat buildup index after vulcanization, and can be evaluated as having improved low heat buildup properties after vulcanization.

[0200] The rubber composition of the present invention is obtained by compounding a rubber component with a specific pyrazolone compound in combination, and exhibits superior tear strength and low heat buildup in the vulcanized rubber. These rubber compositions have improved tear strength after vulcanization, and tires manufactured using these rubber compositions have improved fuel economy.

Claims

1. A rubber composition comprising a rubber component and a compound represented by the following formula (1) and / or a salt thereof: [In the formula, R 1 , and R 2 are the same or different and each represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or an acyl group, or R 1 and R 2 and together represent an alkylene group or an alkylidene group. 3 represents a hydrogen atom, an alkyl group, or an aryl group. 4 , and R 5 are the same or different and each represents a hydrogen atom or an alkyl group, or R 4 , and R 5 and taken together represent an alkylene group or an alkylidene group, each of which may have one or more substituents.

2. The compound represented by the formula (1) is 1 , and R 2 are the same or different and each is a hydrogen atom, an alkyl group, an aryl group, an acyl group, or R 1 and R 2 and together represent an alkylidene group, R 3 represents a hydrogen atom, an alkyl group, or an aryl group; R 4 , and R 5 are the same or different and each is a hydrogen atom, an alkyl group, or R 4 and R 5 2. The rubber composition according to claim 1, wherein and are taken together to represent an alkylidene group.

3. The compound represented by formula (1) is 1 , and R 2 are the same or different and each is a hydrogen atom, an alkyl group, an aryl group, or R 1 and R 2 and together represent an alkylidene group, R 3 represents a hydrogen atom, an alkyl group, or an aryl group; R 4 , and R 5 are the same or different and each is a hydrogen atom, an alkyl group, or R 4 and R 5 2. The rubber composition according to claim 1, wherein and are taken together to represent an alkylidene group.

4. The rubber composition according to claim 1, wherein the compound represented by formula (1) and / or its salt is at least one compound selected from the group consisting of 3-amino-5-pyrazolone, 3-isopropylamino-5-pyrazolone, 3-phenylamino-5-pyrazolone, 3-acetylamino-5-pyrazolone, 3-dodecylideneamino-5-pyrazolone, 3-amino-1-methyl-5-pyrazolone, 3-amino-1-phenyl-5-pyrazolone, 3-amino-4-methyl-5-pyrazolone, and 3-amino-4-phenylalkylidene-5-pyrazolone.

5. The rubber composition according to claim 1, wherein the compound represented by formula (1) and / or a salt thereof is at least one compound selected from the group consisting of 3-amino-5-pyrazolone, 3-isopropylamino-5-pyrazolone, 3-phenylamino-5-pyrazolone, 3-dodecylideneamino-5-pyrazolone, 3-amino-1-methyl-5-pyrazolone, 3-amino-1-phenyl-5-pyrazolone, 3-amino-4-methyl-5-pyrazolone, and 3-amino-4-phenylalkylidene-5-pyrazolone.

6. The rubber composition according to claim 1, wherein the compound represented by formula (1) and / or its salt is at least one compound selected from the group consisting of 3-amino-5-pyrazolone and 3-dodecylideneamino-5-pyrazolone and / or its salt.

7. 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.

8. The rubber composition according to claim 1, wherein the rubber component is natural rubber.

9. The rubber composition according to claim 1, further comprising carbon black and / or an inorganic filler.

10. The rubber composition according to claim 1, which is for use in tires.

11. A tire made using the rubber composition according to any one of claims 1 to 10.

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