WO2010143633A1 - Composition de caoutchouc et pneu obtenu à l'aide de celle-ci - Google Patents

Composition de caoutchouc et pneu obtenu à l'aide de celle-ci Download PDF

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WO2010143633A1
WO2010143633A1 PCT/JP2010/059706 JP2010059706W WO2010143633A1 WO 2010143633 A1 WO2010143633 A1 WO 2010143633A1 JP 2010059706 W JP2010059706 W JP 2010059706W WO 2010143633 A1 WO2010143633 A1 WO 2010143633A1
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natural rubber
rubber
tire
group
rubber composition
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PCT/JP2010/059706
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English (en)
Japanese (ja)
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基之 間宮
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株式会社ブリヂストン
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
    • B60C1/0016—Compositions of the tread
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon

Definitions

  • the present invention relates to a rubber composition and a tire using the rubber composition. More specifically, the present invention relates to a rubber composition that provides a large tire such as a tire for low heat generation and wear resistance, particularly an off-the-road tire, and a tire member such as tread rubber or case rubber. It relates to a tire having the above performance.
  • the most common technique is to use a material having lower heat generation as the rubber composition.
  • a synthetic rubber component such as styrene-butadiene copolymer (SBR) has been used in the tread rubber composition in order to improve wear resistance. It has been improved. It has also been proposed to add a modified conjugated diene polymer such as a modified styrene-butadiene copolymer in order to improve low heat build-up. However, if the amount of the modified conjugated diene polymer is excessively increased, the wear resistance cannot be sufficiently improved, and the fracture resistance is deteriorated.
  • SBR styrene-butadiene copolymer
  • Silica is known as a filler to improve low heat build-up (for example, Patent Documents 1 to 4), but silica tends to aggregate particles and has wettability with rubber. Inferior, not well dispersed in rubber. If the silica is not sufficiently dispersed in the rubber, the rubber composition has a high Mooney viscosity, and there is a problem that the processability such as extrusion is poor.
  • a technique of blending a rubber-filler coupling agent having a specific structure into a rubber composition for example, Patent Document 8
  • a diene rubber and a filler A rubber composition having low heat buildup and wear resistance obtained by adding a vulcanizing agent or a vulcanization accelerator to a heat treated rubber obtained by heat treatment under specific conditions after mixing (for example, Patent Document 9) has been proposed.
  • Patent Document 8 a technique of blending a rubber-filler coupling agent having a specific structure into a rubber composition
  • Patent Document 9 A rubber composition having low heat buildup and wear resistance obtained by adding a vulcanizing agent or a vulcanization accelerator to a heat treated rubber obtained by heat treatment under specific conditions after mixing
  • JP-A-6-248116 Japanese Patent Laid-Open No. 7-70369 JP-A-8-245838 JP-A-3-252431 JP 2006-37046 A Japanese Examined Patent Publication No. 6-53763 International Publication No. 2004/106397 Pamphlet US Patent Application Publication No. 2007/0161756 JP 2008-156548 A
  • the present invention has been made under such circumstances, and a rubber composition that provides a large tire such as a tire having low heat build-up and wear resistance, particularly an off-the-road tire, and a tire member using the rubber composition. It is an object of the present invention to provide a tire having the above performance.
  • the total surface area of the reinforcing filler and the dispersibility of the reinforcing filler are important, that is, the dispersibility of the reinforcing filler is good at a specific total surface area of the reinforcing filler. It was found that the low heat buildup of the rubber composition is improved, the wear resistance is improved if the total surface area of the reinforcing filler is large and the dispersibility of the reinforcing filler is good. Furthermore, the inventors have conducted various experimental studies on indices that can universally evaluate the dispersibility of the reinforcing filler at a specific total surface area of the reinforcing filler. In order to obtain a good rubber composition, it has been found through numerous experiments that the (-30 ° C.
  • tan ⁇ / 60 ° C. tan ⁇ ratio of the vulcanized rubber composition should be increased.
  • the wear resistance of the rubber composition In addition, in relation to the ( ⁇ 30 ° C. tan ⁇ / 60 ° C.
  • cetyltrimethylammonium bromide adsorption specific surface area (m 2 / g) is most preferable as an indicator of the specific total surface area of the reinforcing filler. did.
  • a rubber composition containing natural rubber as a rubber component, carbon black and / or silica as a reinforcing filler, and -30 of vulcanized rubber composition It has been found that the above problem can be solved by adjusting the °C / 60 ° C. tan ⁇ ratio to be larger than a specific formula using the total surface area of the reinforcing filler as a variable.
  • the rubber composition is prepared by using, for example, a natural rubber and carbon black masterbatch or a modified natural rubber as a natural rubber of the rubber component, or using a dispersibility improver of a reinforcing filler in the rubber composition. It discovered that it could achieve by mix
  • Ln (x) is the natural logarithm of x
  • tan ⁇ is the loss tangent of the vulcanized rubber composition.
  • a rubber composition that provides a tire having both low heat build-up and wear resistance, particularly a large tire such as an off-the-road tire, and the tire composition such as tread rubber and case rubber is used for the tire composition.
  • a tire having performance can be provided.
  • FIG. 3 is a plot diagram showing the relationship between x in Formula (1) and ⁇ 30 ° C. tan ⁇ / 60 ° C. tan ⁇ in the rubber compositions obtained in Examples and Comparative Examples.
  • it is a plot figure which shows the relationship between the internal temperature change in a driving
  • Ln (x) is the natural logarithm of x
  • tan ⁇ is the loss tangent of the vulcanized rubber composition. It is characterized by adjusting to satisfy the relationship.
  • the rubber composition of the present invention such that the value of the -30 ° C. tan ⁇ / 60 ° C. tan ⁇ ratio is larger than the y value when the value of “ ⁇ 1026.5Ln (x) +10256” is y, A rubber composition excellent in low heat generation and wear resistance is obtained, and by using this rubber composition for a tire member, a tire having both low heat generation and wear resistance, particularly a tire for large heavy loads or off-the-road use. Can be given.
  • x is “CTAB ⁇ A”
  • CTAB is the cetyltrimethylammonium bromide adsorption specific surface area (m 2 / g) measured according to ISO 6810 of the reinforcing filler
  • A is Since it is a mass part of the reinforcing filler per 100 parts by mass of natural rubber, x means the total surface area of the reinforcing filler.
  • x is a number in the range of 2500 to 13000.
  • the ⁇ 30 ° C. tan ⁇ and 60 ° C. tan ⁇ of the vulcanized rubber composition are values measured by the following method. ⁇ Measurement of ⁇ 30 ° C. tan ⁇ and 60 ° C.
  • tan ⁇ > A vulcanized rubber composition obtained by vulcanizing a rubber composition at 150 ° C. for 90 minutes was measured from 100 ° C. to ⁇ 60 ° C. using a shear viscoelasticity measuring apparatus [“Ares” manufactured by Rheometrics Co., Ltd.]. The tan ⁇ at °C and the tan ⁇ at ⁇ 30 ° C. were determined. The tan ⁇ at 60 ° C. was a value at a frequency of 10 Hz and a dynamic strain of 3%, and the tan ⁇ at ⁇ 30 ° C. was a value at a frequency of 10 Hz and a dynamic strain of 0.1%.
  • the type of carbon black or silica that is the reinforcing filler in the rubber composition the selection of the quantity ratio, (1) Use natural rubber in the form of a masterbatch of natural rubber and carbon black, (2) Use modified natural rubber, (3) Reinforcing fillers such as rubber-filler coupling agents This is achieved by taking measures such as using a dispersibility improver, (4) using a heat treatment masterbatch obtained by mixing natural rubber and a reinforcing filler, and then heat-treating under predetermined conditions. be able to.
  • Carbon black and / or silica In the rubber composition of the present invention, carbon black and / or silica is used as the reinforcing filler.
  • carbon black There is no restriction
  • This carbon black preferably has a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) measured in accordance with ISO 6810 in the range of 20 to 200 m 2 / g, and in the range of 70 to 160 m 2 / g. Those are more preferred.
  • CTAB cetyltrimethylammonium bromide adsorption specific surface area
  • silica examples include wet silica (hydrous silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and the like. Among these, wet silica is preferable.
  • the wet silica preferably has a CATB specific surface area of 100 to 300 m 2 / g. Silica having a CATB specific surface area within this range has an advantage that both rubber reinforcement and dispersibility in a rubber component can be achieved. From this viewpoint, silica having a CATB specific surface area in the range of 150 to 250 m 2 / g is more preferable.
  • silica commercially available products such as “Nipsil AQ”, “Nipsil KQ” manufactured by Tosoh Silica Co., Ltd., “Ultrasil VN3” manufactured by Degussa Co., Ltd. can be used. This silica may be used alone or in combination of two or more.
  • the reinforcing filler only carbon black may be used, silica alone may be used, or carbon black and silica may be used in combination.
  • the reinforcing filler is preferably 20 to 120 parts by weight, more preferably 25 to 100 parts by weight, still more preferably 100 parts by weight of natural rubber, from the viewpoint of reinforcing properties and the effect of improving various properties thereby. It is blended at a ratio of 30 to 90 parts by mass.
  • the natural rubber can be used in the form of a masterbatch of natural rubber and carbon black (hereinafter sometimes referred to as a natural rubber masterbatch).
  • This master batch is preferably a wet master batch of natural rubber latex and carbon black.
  • This natural rubber masterbatch is preferably a wet masterbatch in which carbon black is mixed with natural rubber latex, and the production method is preferably such that after decomposing the amide bond in the latex, the natural rubber latex and carbon black are dispersed in water. And a step of mixing, coagulating, and drying the resulting aqueous slurry.
  • a slurry liquid in which carbon black is dispersed in water in advance Prior to mixing the natural rubber latex and the aqueous dispersion slurry liquid, a slurry liquid in which carbon black is dispersed in water in advance is produced.
  • the manufacturing method of this slurry can use a well-known method, and is not specifically limited.
  • the water dispersion slurry of carbon black can be prepared, for example, by putting a predetermined amount of carbon black and water in a homomixer and stirring for a certain time.
  • the concentration of carbon black in the slurry is preferably from 0.5 to 30% by mass, particularly preferably from 1 to 15% by mass, based on the slurry.
  • the volume average particle size (mv) is preferably 25 ⁇ m or less and the 90 volume% particle size (D90) is preferably 30 ⁇ m or less.
  • the volume average particle size is 25 ⁇ m or less and the 90% by volume particle size is 30 ⁇ m or less, the carbon black dispersion in the rubber is further improved, and the reinforcing property and wear resistance are further improved.
  • excessive shearing force is applied to the slurry to reduce the particle size of the carbon black, the structure of the carbon black is destroyed and the reinforcing property is deteriorated.
  • 24M4DBP oil absorption of the carbon black recovered by drying from the aqueous dispersion slurry liquid The amount is preferably mixed so as to maintain 93% or more, more preferably 96% or more of the 24M4DBP oil absorption before being dispersed in water.
  • the amount of carbon black mixed when mixing the natural rubber latex and the water-dispersed slurry is usually about 10 to 100 parts by mass with respect to 100 parts by mass of the natural rubber component in the natural rubber latex. If it is less than 10 parts by mass, sufficient wear resistance cannot be obtained, and if it exceeds 100 parts by mass, the low heat build-up is reduced.
  • the mixing amount of carbon black is preferably 20 to 80 parts by mass, and more preferably 30 to 60 parts by mass. Through this mixing step, a natural rubber wet masterbatch is obtained.
  • the natural rubber wet masterbatch obtained through the mixing step is preferably coagulated in the coagulation step.
  • the wet masterbatch is solidified by using a solidifying agent such as formic acid or sulfuric acid or a salt such as sodium chloride as usual.
  • coagulation may be performed by adding natural rubber latex and the slurry liquid without adding a coagulant.
  • drying process It is preferable to perform a drying process as the final step of master batch production.
  • ordinary dryers such as vacuum dryers, air dryers, drum dryers, band dryers, etc. can be used, but in order to further improve the dispersibility of carbon black, while applying mechanical shearing force It is preferable to dry. Thereby, rubber excellent in processability and reinforcement can be obtained.
  • this drying can be performed using a general kneader, it is preferable to use a continuous kneader. Furthermore, it is more preferable to use a multi-axis kneading extruder that rotates in the same direction or in different directions.
  • the moisture in the master batch before the drying step is preferably 10% by mass or more. This is because when the water content is less than 10% by mass, the dispersion improvement width of the carbon black in the drying process becomes small.
  • the natural rubber latex used in the mixing step may be subjected to a step of decomposing amide bonds in the latex. If the amide bond is decomposed in advance, molecules are entangled by the hydrogen bondability of the amide bond, the viscosity increase of the rubber is small, and the processability can be improved.
  • a protease and / or an aromatic polycarboxylic acid derivative it is preferable to use a protease and / or an aromatic polycarboxylic acid derivative.
  • Proteases have the property of hydrolyzing amide bonds present in the surface layer components of natural rubber latex particles, and examples include acidic proteases, neutral proteases, and alkaline proteases.
  • alkaline protease is particularly preferred from the viewpoint of effect.
  • the amide bond is decomposed by a protease, it may be carried out under conditions suitable for the enzyme to be mixed.
  • the temperature is usually 20 to 80 ° C. It is desirable to process with a range.
  • the pH at this time is usually in the range of 6.0 to 12.0.
  • the amount of protease added is usually in the range of 0.01 to 2% by mass, preferably 0.02 to 1% by mass, based on the natural rubber latex.
  • the addition amount of the aromatic polycarboxylic acid derivative is preferably 0.01 to 30% by mass with respect to the natural rubber latex. If the addition amount is less than 0.01% by mass, the Mooney viscosity may not be sufficiently reduced. On the other hand, if it exceeds 30% by mass, not only the effect corresponding to the increase is obtained but also the vulcanized rubber is destroyed. May adversely affect properties.
  • the addition amount varies within the above range depending on the type and grade of the natural rubber latex used, but it is preferably in the range of 0.05 to 20% by mass from the physical properties and cost.
  • the aromatic polycarboxylic acid derivative is preferably a derivative of phthalic acid, trimellitic acid, pyromellitic acid and its anhydride, specifically, monostearyl phthalate, monodecyl phthalate, monophthalic acid Examples include octylamide, polyoxyethylene lauryl phthalate, monodecyl trimellitic acid, monostearyl trimellitic acid, monostearyl pyromellitic acid, and distearyl pyromellitic acid.
  • a surfactant for the purpose of improving the stability of the latex.
  • anionic, cationic, nonionic and amphoteric surfactants can be used, and anionic and nonionic surfactants are particularly preferable.
  • the addition amount of the surfactant can be appropriately adjusted according to the properties of the natural rubber latex, but is usually 0.01 to 2% by mass, preferably 0.02 to 1% by mass with respect to the natural rubber latex. .
  • the addition of the surfactant is preferably performed in the amide bond decomposition step, but is not particularly limited as long as it is at least before the mixing step.
  • modified natural rubber can be used as the natural rubber.
  • natural rubber latex may be used as a raw material, or at least one solid natural rubber raw material selected from natural rubber, natural rubber latex coagulum and natural rubber cup lamp is used. May be.
  • the natural rubber latex is not particularly limited, and for example, a field latex, an ammonia-treated latex, a centrifugal concentrated latex, a deproteinized latex treated with a surfactant or an enzyme, and a combination thereof can be used. .
  • a polar group-containing modified natural rubber in the production of modified natural rubber, for example, when natural rubber latex is used as a raw material, a polar group-containing modified natural rubber can be obtained by producing a polar group-containing modified natural rubber latex and further coagulating and drying.
  • the production method of the polar group-containing modified natural rubber latex is not particularly limited. For example, (1) a polar group-containing monomer is added to the natural rubber latex, and the polar group-containing monomer is used as a natural rubber.
  • a method of adding a polar group-containing mercapto compound to natural rubber latex and adding the polar group-containing mercapto compound to the natural rubber molecule in natural rubber latex (3) ) A method of adding a polar group-containing olefin and a metathesis catalyst to natural rubber latex, and reacting the polar group-containing olefin with a natural rubber molecule in the natural rubber latex using the metathesis catalyst, (4) perbenzoic acid, Reaction of organic peracids such as acetic acid, performic acid, perphthalic acid, perpropionic acid, trifluoroperacetic acid under severe conditions A method of obtaining a rubber having a main chain reactive functional groups such as epoxidized natural rubbers by.
  • the polar group-containing monomer added to the natural rubber latex is not particularly limited as long as it has at least one polar group in the molecule and can be graft-polymerized with the natural rubber molecule.
  • the polar group-containing monomer preferably has a carbon-carbon double bond in the molecule for graft polymerization with a natural rubber molecule, and is preferably a polar group-containing vinyl monomer.
  • Specific examples of the polar group include amino group, imino group, nitrile group, ammonium group, imide group, amide group, hydrazo group, azo group, diazo group, hydroxyl group, carboxyl group, carbonyl group, epoxy group, and oxycarbonyl.
  • Preferred examples include a group, sulfide group, disulfide group, sulfonyl group, sulfinyl group, thiocarbonyl group, nitrogen-containing heterocyclic group, oxygen-containing heterocyclic group, alkoxysilyl group, and tin-containing group.
  • These monomers containing a polar group may be used alone or in combination of two or more.
  • Examples of the monomer containing an amino group include polymerizable monomers containing at least one amino group selected from primary, secondary, and tertiary amino groups in one molecule.
  • a tertiary amino group-containing monomer such as dialkylaminoalkyl (meth) acrylate is particularly preferable.
  • These amino group-containing monomers may be used alone or in combination of two or more.
  • examples of the primary amino group-containing monomer include acrylamide, methacrylamide, 4-vinylaniline, aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, aminobutyl (meth) ) Acrylate and the like.
  • the secondary amino group-containing monomer includes (1) anilinostyrene, ⁇ -phenyl-p-anilinostyrene, ⁇ -cyano-p-anilinostyrene, ⁇ -cyano- ⁇ -methyl-p. -Anilinostyrene, ⁇ -chloro-p-anilinostyrene, ⁇ -carboxy-p-anilinostyrene, ⁇ -methoxycarbonyl-p-anilinostyrene, ⁇ - (2-hydroxyethoxy) carbonyl-p-anilino
  • Anilinostyrenes such as styrene, ⁇ -formyl-p-anilinostyrene, ⁇ -formyl- ⁇ -methyl-p-anilinostyrene, ⁇ -carboxy- ⁇ -carboxy- ⁇ -phenyl-p-anilinostyrene, (2) 1-anilinophenyl-1,3-butadiene, 1-anil
  • examples of the tertiary amino group-containing monomer include N, N-disubstituted aminoalkyl (meth) acrylate and N, N-disubstituted aminoalkyl (meth) acrylamide.
  • examples of the N, N-disubstituted aminoalkyl (meth) acrylate include N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and N, N-dimethylaminopropyl (meth).
  • N, N -Dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, N, N-dioctylaminoethyl (meth) acrylate, N-methyl-N -Ethylaminoethyl (meth) acrylate and the like are particularly preferred.
  • N, N-disubstituted aminoalkyl (meth) acrylamide examples include N, N-dimethylaminomethyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl ( (Meth) acrylamide, N, N-dimethylaminobutyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-diethylaminobutyl (meth) acrylamide, N -Methyl-N-ethylaminoethyl (meth) acrylamide, N, N-dipropylaminoethyl (meth) acrylamide, N, N-dibutylaminoethyl (meth) acrylamide, N, N-dibuty
  • Examples of the monomer containing a nitrile group include (meth) acrylonitrile and vinylidene cyanide. These nitrile group-containing monomers may be used alone or in a combination of two or more.
  • Examples of the monomer containing a hydroxyl group include polymerizable monomers having at least one hydroxyl group in one molecule.
  • Examples of such monomers include hydroxyl group-containing unsaturated carboxylic acid monomers, hydroxyl group-containing vinyl ether monomers, hydroxyl group-containing vinyl ketone monomers, and the like.
  • hydroxyl group-containing unsaturated carboxylic acid monomer examples include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxy Hydroxyalkyl (meth) acrylates such as butyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate; polyalkylene glycols such as polyethylene glycol and polypropylene glycol (the number of alkylene glycol units is For example, 2 to 23) mono (meth) acrylates; N-hydroxymethyl (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N, N-bis (2-hydroxymethyl) ( Me ) Hydroxyl group-containing unsaturated amides such as acrylamide; o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene,
  • a hydroxyl group-containing unsaturated carboxylic acid monomer and a hydroxyl group-containing vinyl aromatic compound are preferable, and a hydroxyl group-containing unsaturated carboxylic acid monomer is particularly preferable.
  • examples of the hydroxyl group-containing unsaturated carboxylic acid monomer include esters such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, amides, and anhydrides.
  • esters such as acrylic acid and methacrylic acid.
  • These hydroxyl group-containing monomers may be used alone or in a combination of two or more.
  • Examples of the monomer containing a carboxyl group include unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, tetraconic acid and cinnamic acid; non-phthalic acid, succinic acid, adipic acid and the like.
  • Examples thereof include free carboxyl group-containing esters such as monoesters of a polymerizable polycarboxylic acid and a hydroxyl group-containing unsaturated compound such as (meth) allyl alcohol and 2-hydroxyethyl (meth) acrylate, and salts thereof. Of these, unsaturated carboxylic acids are particularly preferred.
  • These carboxyl group-containing monomers may be used alone or in a combination of two or more.
  • Examples of the monomer containing an epoxy group include (meth) allyl glycidyl ether, glycidyl (meth) acrylate, 3,4-epoxycyclohexyl (meth) acrylate, and the like. These epoxy group-containing monomers may be used alone or in combination of two or more.
  • the nitrogen-containing heterocyclic ring includes pyrrole, histidine, imidazole, triazolidine, triazole, triazine, pyridine, pyrimidine, pyrazine, indole, quinoline, purine, phenazine, pteridine, Examples include melamine.
  • the nitrogen-containing heterocycle may contain other heteroatoms in the ring.
  • a monomer containing a pyridyl group as a nitrogen-containing heterocyclic group 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 5-methyl-2-vinylpyridine, 5-ethyl-2- Examples thereof include a vinyl compound containing a pyridyl group such as vinylpyridine, and among these, 2-vinylpyridine, 4-vinylpyridine and the like are particularly preferable.
  • These nitrogen-containing heterocyclic group-containing monomers may be used alone or in a combination of two or more.
  • Examples of the monomer containing the alkoxysilyl group include (meth) acryloxymethyltrimethoxysilane, (meth) acryloxymethylmethyldimethoxysilane, (meth) acryloxymethyldimethylmethoxysilane, and (meth) acryloxymethyltrimethylsilane.
  • Examples of the monomer having a tin-containing group include allyltri-n-butyltin, allyltrimethyltin, allyltriphenyltin, allyltri-n-octyltin, (meth) acryloxy-n-butyltin, and (meth) acryloxytrimethyltin.
  • tin-containing monomers such as (meth) acryloxytriphenyltin, (meth) acryloxy-n-octyltin, vinyltri-n-butyltin, vinyltrimethyltin, vinyltriphenyltin, vinyltri-n-octyltin Can do. These tin-containing monomers may be used alone or in combination of two or more.
  • the graft polymerization of the polar group-containing monomer to the natural rubber molecule is preferably performed by emulsion polymerization.
  • the polar group-containing monomer in general, is added to a liquid obtained by adding water and, if necessary, an emulsifier to natural rubber latex, and a polymerization initiator is further added thereto. It is preferable to polymerize the polar group-containing monomer by stirring at the temperature.
  • an emulsifier may be added in advance to the natural rubber latex, or after emulsifying the polar group-containing monomer with the emulsifier, May be added.
  • an emulsifier which can be used for emulsification of a natural rubber latex and / or a polar group containing monomer, Nonionic surfactants, such as polyoxyethylene lauryl ether, are mentioned.
  • the polymerization initiator is not particularly limited, and various polymerization initiators for emulsion polymerization can be used, and the addition method is not particularly limited.
  • Examples of commonly used polymerization initiators include benzoyl peroxide, hydrogen peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, 2,2-azobisisobutyronitrile, 2,2-azobis (2-diaminopropane) hydrochloride, 2,2-azobis (2-diaminopropane) dihydrochloride, 2,2-azobis (2,4-dimethylvaleronitrile), potassium persulfate, sodium persulfate And ammonium persulfate.
  • a redox polymerization initiator In order to lower the polymerization temperature, it is preferable to use a redox polymerization initiator.
  • the reducing agent to be combined with the peroxide in the redox polymerization initiator include tetraethylenepentamine, mercaptans, acidic sodium sulfite, reducing metal ions, ascorbic acid and the like.
  • a preferred combination of a peroxide and a reducing agent in the redox polymerization initiator includes a combination of tert-butyl hydroperoxide and tetraethylenepentamine.
  • the amount of the polymerization initiator added is preferably in the range of 1 to 100 mol%, more preferably in the range of 10 to 100 mol% with respect to the polar group-containing monomer.
  • the above-mentioned components are charged into a reaction vessel and reacted at about 30 to 80 ° C. for about 10 minutes to 7 hours to obtain a modified natural rubber latex in which the polar group-containing monomer is graft copolymerized with natural rubber molecules. .
  • the modified natural rubber latex is coagulated, washed, and then dried using a dryer such as a vacuum dryer, an air dryer, a drum dryer or the like to obtain a modified natural rubber.
  • the coagulant used for coagulating the modified natural rubber latex is not particularly limited, and examples thereof include acids such as formic acid and sulfuric acid, and salts such as sodium chloride.
  • the polar group-containing mercapto compound that is added to the natural rubber latex and undergoes an addition reaction with the natural rubber molecule in the natural rubber latex as long as it has at least one mercapto group and a polar group other than the mercapto group in the molecule. It is not limited.
  • polar group examples include amino group, imino group, nitrile group, ammonium group, imide group, amide group, hydrazo group, azo group, diazo group, hydroxyl group, carboxyl group, carbonyl group, epoxy group, oxycarbonyl
  • Preferred examples include a group, a nitrogen-containing heterocyclic group, a mixed oxygen heterocyclic group, an alkoxysilyl group, and a tin-containing group. These mercapto compounds containing polar groups may be used alone or in combination of two or more.
  • Examples of the mercapto compound containing an amino group include mercapto compounds having at least one amino group selected from primary, secondary and tertiary amino groups in one molecule.
  • a tertiary amino group-containing mercapto compound is particularly preferable.
  • the primary amino group-containing mercapto compound 4-mercaptoaniline, 2-mercaptoethylamine, 2-mercaptopropylamine, 3-mercaptopropylamine, 2-mercaptobutylamine, 3-mercaptobutylamine, 4-mercaptobutylamine Etc.
  • Examples of the secondary amino group-containing mercapto compounds include N-methylaminoethanethiol, N-ethylaminoethanethiol, N-methylaminopropanethiol, N-ethylaminopropanethiol, N-methylaminobutanethiol, N- And ethylaminobutanethiol.
  • the tertiary amino group-containing mercapto compounds include N, N-dimethylaminoethanethiol, N, N-diethylaminoethanethiol, N, N-dimethylaminopropanethiol, N, N-diethylaminopropanethiol, N, N -N, N-disubstituted aminoalkyl mercaptans such as dimethylaminobutanethiol and N, N-diethylaminobutanethiol.
  • 2-mercaptoethylamine and N, N-dimethylaminoethanethiol are preferred.
  • These amino group-containing mercapto compounds may be used alone or in combination of two or more.
  • Examples of the mercapto compound having a nitrile group include 2-mercaptopropane nitrile, 3-mercaptopropane nitrile, 2-mercaptobutane nitrile, 3-mercaptobutane nitrile, 4-mercaptobutane nitrile, and the like. These nitrile group-containing mercapto compounds May be used singly or in combination of two or more.
  • Examples of the mercapto compound containing a hydroxyl group include mercapto compounds having at least one primary, secondary, or tertiary hydroxyl group in one molecule.
  • Specific examples of the hydroxyl group-containing mercapto compound include 2-mercaptoethanol, 3-mercapto-1-propanol, 3-mercapto-2-propanol, 4-mercapto-1-butanol, 4-mercapto-2-butanol, 3 -Mercapto-1-butanol, 3-mercapto-2-butanol, 3-mercapto-1-hexanol, 3-mercapto-1,2-propanediol, 2-mercaptobenzyl alcohol, 2-mercaptophenol, 4-mercaptophenol, etc.
  • 2-mercaptoethanol and the like are preferable.
  • These hydroxyl group-containing mercapto compounds may be used alone or in combination of two or more.
  • Examples of the mercapto compound containing a carboxyl group include mercaptoacetic acid, mercaptopropionic acid, thiosalicylic acid, mercaptomalonic acid, mercaptosuccinic acid, mercaptobenzoic acid, and the like. Among these, mercaptoacetic acid is preferred. These carboxyl group-containing mercapto compounds may be used individually by 1 type, and may be used in combination of 2 or more type.
  • the nitrogen-containing heterocyclic ring includes pyrrole, histidine, imidazole, triazolidine, triazole, triazine, pyridine, pyrimidine, pyrazine, indole, quinoline, purine, phenazine, pteridine, melamine. Etc.
  • the nitrogen-containing heterocycle may contain other heteroatoms in the ring.
  • mercapto compounds containing a pyridyl group as a nitrogen-containing heterocyclic group 2-mercaptopyridine, 3-mercaptopyridine, 4-mercaptopyridine, 5-methyl-2-mercaptopyridine, 5-ethyl-2-mercapto
  • mercapto compounds containing other nitrogen-containing heterocyclic groups include 2-mercaptopyrimidine, 2-mercapto-5-methylbenzimidazole, 2-mercapto-1-methylimidazole, 2-mercapto. Examples include benzimidazole and 2-mercaptoimidazole.
  • 2-mercaptopyridine, 4-mercaptopyridine and the like are preferable.
  • These nitrogen-containing heterocyclic group-containing mercapto compounds may be used alone or in combination of two or more.
  • Examples of the mercapto compound containing an alkoxysilyl group include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyldimethylmethoxysilane, 2-mercaptoethyltrimethoxysilane. Examples include silane, 2-mercaptoethyltriethoxysilane, mercaptomethylmethyldiethoxysilane, mercaptomethyltrimethoxysilane, and the like. Among these, 3-mercaptopropyltrimethoxysilane is preferable. These alkoxysilyl group-containing mercapto compounds may be used alone or in combination of two or more.
  • Examples of the mercapto compound having a tin-containing group include 2-mercaptoethyltri-n-butyltin, 2-mercaptoethyltrimethyltin, 2-mercaptoethyltriphenyltin, 3-mercaptopropyltri-n-butyltin, and 3-mercaptopropyl. Mention may be made of tin-containing mercapto compounds such as trimethyltin and 3-mercaptopropyltriphenyltin. These tin-containing mercapto compounds may be used individually by 1 type, and may be used in combination of 2 or more type.
  • the polar group-containing mercapto compound When adding the polar group-containing mercapto compound to the natural rubber molecule in the natural rubber latex, generally, the polar group-containing mercapto compound is added to a solution obtained by adding water and an emulsifier as necessary to the natural rubber latex, By stirring at a predetermined temperature, the polar group-containing mercapto compound is added to the double bond of the main chain of the natural rubber molecule in the natural rubber latex.
  • an emulsifier may be added to the natural rubber latex in advance, or the polar group-containing mercapto compound may be added to the natural rubber latex after being emulsified with the emulsifier. good.
  • an organic peroxide can also be added as needed.
  • it does not specifically limit as an emulsifier which can be used for emulsification of natural rubber latex and / or a polar group containing mercapto compound, Nonionic surfactants, such as polyoxyethylene lauryl ether, are mentioned.
  • the polar group-containing mercapto compound is introduced in a small amount and uniformly into each natural rubber molecule.
  • the modification reaction is preferably performed with stirring.
  • the above components such as natural rubber latex and a polar group-containing mercapto compound are charged into a reaction vessel and reacted at about 30 to 80 ° C. for about 10 minutes to 24 hours.
  • a modified natural rubber latex in which the polar group-containing mercapto compound is added to natural rubber molecules is obtained.
  • the polar group-containing olefin added to the natural rubber latex has at least one polar group in the molecule, and also has a carbon-carbon double bond for cross-metathesis reaction with the natural rubber molecule.
  • specific examples of the polar group include amino group, imino group, nitrile group, ammonium group, imide group, amide group, hydrazo group, azo group, diazo group, hydroxyl group, carboxyl group, carbonyl group, and epoxy group.
  • Preferable examples include oxycarbonyl group, sulfide group, disulfide group, sulfonyl group, sulfinyl group, thiocarbonyl group, nitrogen-containing heterocyclic group, oxygen-containing heterocyclic group, alkoxysilyl group, and tin-containing group.
  • These polar group-containing olefins may be used singly or in combination of two or more.
  • the polar group-containing olefin When the polar group-containing olefin is reacted with the natural rubber molecule in the natural rubber latex by the metathesis catalyst, generally, the polar group-containing olefin is added to a liquid obtained by adding water and an emulsifier as necessary to the natural rubber latex, Further, a metathesis catalyst is added and stirred at a predetermined temperature to cause a metathesis reaction between the natural rubber molecule and the polar group-containing olefin.
  • an emulsifier may be added to the natural rubber latex in advance, or the polar group-containing olefin may be added to the natural rubber latex after emulsifying the polar group-containing olefin with the emulsifier. good.
  • an emulsifier which can be used for emulsification of natural rubber latex and / or a polar group containing olefin, Nonionic surfactants, such as polyoxyethylene lauryl ether, are mentioned.
  • the metathesis catalyst is not particularly limited as long as it has a catalytic action on the metathesis reaction between the natural rubber molecule and the polar group-containing olefin, and various metathesis catalysts can be used.
  • the metathesis catalyst contains a transition metal, but since it is used in a natural rubber latex, it is preferable that the stability to water is high. Therefore, the transition metal constituting the metathesis catalyst is preferably any one of ruthenium, osmium, and iridium.
  • Cy represents a cyclohexyl group
  • Cp represents a cyclopentyl group
  • Ph represents a phenyl group.
  • the addition amount of the metathesis catalyst is preferably in the range of 1 to 500 mol%, more preferably in the range of 10 to 100 mol% with respect to the polar group-containing olefin.
  • the above-mentioned components are charged into a reaction vessel and reacted at about 30 to 80 ° C. for about 10 minutes to 24 hours, thereby obtaining a modified natural rubber latex in which the polar group is introduced into natural rubber molecules.
  • a polar group-containing compound is given a mechanical shearing force
  • a modified natural rubber is obtained by graft polymerization or addition to a raw material.
  • the natural rubber raw material various solid natural rubbers after drying, various natural rubber latex coagulates (including unsmoked sheets) or natural rubber cup lamps can be used, and these natural rubber raw materials are used alone. It may also be used in combination of two or more.
  • the polar group-containing compound When the polar group-containing compound is graft-polymerized to a natural rubber molecule in a natural rubber raw material, the polar group-containing compound preferably has a carbon-carbon double bond in the molecule, and the polar group-containing vinyl monomer It is preferable that On the other hand, when a polar group-containing compound is subjected to an addition reaction with a natural rubber molecule in a natural rubber raw material, the polar group-containing compound preferably has a mercapto group in the molecule, and is preferably a polar group-containing mercapto compound.
  • a biaxial extrusion kneader and a dry prebreaker are preferable.
  • the polar group-containing compound is graft-polymerized to the natural rubber molecule in the natural rubber raw material
  • the natural rubber raw material and the polar group-containing compound preferably, the polar group-containing vinyl are contained in the apparatus to which the mechanical shearing force is applied.
  • a polar group-containing compound when a polar group-containing compound is subjected to an addition reaction with a natural rubber molecule in a natural rubber raw material, the natural rubber raw material and the polar group-containing compound (preferably, a polar group-containing mercapto compound are contained in the above-described mechanical shear force device. ) And, if necessary, organic peroxides and the like are further added to give mechanical shearing force, so that a polar group-containing compound is added to the double bond of the main chain of the natural rubber molecule in the natural rubber raw material. An addition reaction can be performed.
  • the polar group-containing compound used here include the above-described polar group-containing monomers, polar group-containing mercapto compounds, polar group-containing olefins, and the like.
  • the modified natural rubber in which the above-mentioned polar group-containing compound is graft-polymerized or added to the natural rubber molecule is obtained by charging each component described above into a device that can be applied with a mechanical shear force and applying the mechanical shear force.
  • the modification reaction of the natural rubber molecule may be carried out by heating, and preferably at 30 to 160 ° C., more preferably 50 to 130 ° C., the modified natural rubber with sufficient reaction efficiency. Can be obtained.
  • the polar group content of the modified natural rubber is preferably in the range of 0.001 to 0.5 mmol / g, more preferably in the range of 0.002 to 0.3 mmol / g, relative to the rubber component in the modified natural rubber. A range of 0.003 to 0.2 mmol / g is even more preferable. When the polar group content of the modified natural rubber is less than 0.001 mmol / g, the low heat build-up and wear resistance of the rubber composition may not be sufficiently improved.
  • the polar group content of the modified natural rubber exceeds 0.5 mmol / g, the physical properties inherent to natural rubber such as viscoelasticity and SS characteristics (stress-strain curve in a tensile testing machine) will be greatly changed. In addition, the physical properties inherent to natural rubber are impaired, and the processability of the rubber composition may be greatly deteriorated.
  • various low exothermic improvers or low exothermic deterioration inhibitors shown below can be blended.
  • Low exothermic improver In the rubber composition of the present invention, compounds that can be used as a low exothermic improver or a low exothermic decrease inhibitor include (1) a compound that becomes a rubber-filler coupling agent, a nitrosoquinoline compound, a hydrazide compound, QAB type compounds having a bipolar nitrogen-containing moiety can be used.
  • Rubber-filler coupling agent examples include disulfide compounds having a heterocyclic group such as bis [2- (2-oxazolyl) phenyl] disulfide or bis [2- (2-thiazolyl) phenyl] disulfide. .
  • Each of these compounds has a structure in which a 2- (2-oxazolyl) phenyl group or 2- (2-thiazolyl) phenyl group is bonded to each sulfur atom of the disulfide moiety.
  • the sulfur atom of the disulfide moiety is cleaved to form two 2- (2-oxazolyl) phenyl sulfide groups or 2- (2-thiazolyl) phenyl sulfide groups, and the sulfide moieties of these groups bind to natural rubber
  • the oxazolyl moiety or thiazolyl moiety binds to carbon black to exert a coupling action.
  • carbon black is highly dispersed in the rubber composition, and the low heat buildup and wear resistance of the rubber composition are improved.
  • the coupling agent is blended in an amount of about 0.1 to 10 parts by mass with respect to 100 parts by mass of natural rubber.
  • Nitrosoquinoline compounds are known as compounds to be incorporated into rubber compositions in order to realize low heat buildup and high reinforcement of tread rubber. Specifically, 5-nitroso-8-hydroxyquinoline, 7-nitroso -8-hydroxy-5-methylquinoline, 5-nitroso-8-hydroxy-6-methylquinoline, 8-nitroso-5-hydroxy-6-methylquinoline, 5-nitroso-8-hydroxy-7-methylquinoline, 6 -Nitroso-5-hydroxy-8-methylquinoline is preferable, among which 5-nitroso-8-hydroxyquinoline is preferable.
  • the nitrosoquinoline compound is blended in an amount of about 0.1 to 10 parts by mass with respect to 100 parts by mass of natural rubber.
  • Hydrazide compounds especially when blended into rubber compositions suitable for tread rubber of heavy duty pneumatic tires, suppress the decrease in elastic modulus due to overvulcanization due to reversion, and reduce low heat buildup and wear resistance. It is known to have an inhibitory action.
  • the hydrazide compound that can be used in the present invention include 1-hydroxy-N ′-(1-methylethylidene) -2-naphthoic acid hydrazide, 1-hydroxy-N ′-(1-methylpropylidene) -2-naphthoyl.
  • Acid hydrazide 1-hydroxy-N ′-(1-methylbutylidene) -2-naphthoic acid hydrazide, 1-hydroxy-N ′-(1,3-dimethylbutylidene) -2-naphthoic acid hydrazide, 1-hydroxy -N '-(2,6-dimethyl-4-heptylidene) -2-naphthoic acid hydrazide, 2-hydroxy-N'-(1-methylethylidene) -3-naphthoic acid hydrazide, 2-hydroxy-N '-( 1-methylpropylidene) -3-naphthoic acid hydrazide, 2-hydroxy-N ′-(1-methylbutylidene) -3-naphthoic acid hydrazide, 2-hydride Xylon-N ′-(1,3-dimethylbutylidene) -3-naphthoic acid
  • QAB type compound having a bipolar nitrogen-containing moiety In the rubber composition of the present invention, a QAB type compound having a bipolar nitrogen-containing portion can be used.
  • This QAB type compound has the following general formula QAB Wherein Q represents a dipolar nitrogen atom-containing moiety, B represents an oxazoline moiety, a thiazoline moiety, an alkoxysilane moiety or an allyltin moiety, and A represents a linking atom or group that forms a bridge between Q and B. Show.) It is a compound which has a structure represented by these.
  • Q in the compound represented by this general formula is preferably a dipolar nitrogen-containing moiety capable of adding a 1,3-dipole to an unsaturated carbon-carbon bond in the molecular structure of natural rubber.
  • examples of such Q include nitrone, nitrile oxide, and nitrile imine.
  • the QAB type compound has, as Q, a dipolar nitrogen-containing moiety such as nitrone, nitrile oxide, nitrileimine, etc., and this dipolar nitrogen-containing moiety is unsaturated in the molecular structure of natural rubber. Add a 1,3-dipole to the carbon-carbon bond.
  • B has an oxazoline portion, a thiazoline portion, an alkoxysilane portion, an allyltin portion, and the like, and these react with the surface group of the component silica and / or carbon black which is a reinforcing filler.
  • the QAB type compound has an action of coupling natural rubber and reinforcing filler, and improves the dispersion of reinforcing filler such as silica and carbon black in the natural rubber.
  • the rubber composition of the present invention is excellent in low heat buildup and wear resistance.
  • Examples of the QAB compound represented by the general formula include 4- (2-oxazolyl) -phenyl-N-methyl-nitrone, 4- (2-thiazolyl) -phenyl-N-methyl-nitrone, 4- (2-oxazolyl) -phenyl-N-phenyl-nitrone, 4- (2-thiazolyl) -phenyl-N-phenyl-nitrone, phenyl-N-4- (2-oxazolyl) -phenyl-nitrone, phenyl- N-4- (2-thiazolyl) -phenyl-nitrone, 4-tolyl-N-4- (2-oxazolyl) -phenyl-nitrone, 4-tolyl-N-4- (2-thiazolyl) -phenyl-nitrone, 4-methoxyphenyl-N-4- (2-oxazolyl) -phenyl-nitrone, 4-methoxyphenyl-N-4- (2-oxazoly
  • the wet masterbatch or dry masterbatch used in the rubber composition of the present invention is preferably used after heat treatment.
  • the heat treatment of the masterbatch is performed by mixing natural rubber and the reinforcing filler by a wet masterbatch or dry masterbatch method and then heat-treating them under predetermined conditions.
  • the treatment temperature T (° C.) is 50 ° C. or more, preferably 200 ° C. or less
  • the treatment time t (min) is 2 ⁇ 10 +20 ⁇ . obtained by heat treatment at T -8.42>t> 1 ⁇ 10 +13 ⁇ T -5.4228 -3.3 conditions.
  • the resulting heat-treated masterbatch does not contain a vulcanizing agent.
  • a masterbatch composed of natural rubber and carbon black and / or silica which is a reinforcing filler
  • the rubber composition using this heat-treated master batch has sufficient low heat buildup and wear resistance.
  • a method for obtaining the heat treatment masterbatch a method in which the masterbatch is allowed to remain in a constant temperature apparatus such as an oven for a predetermined time under the above conditions may be used, or natural rubber and a reinforcing filler may be placed in a Banbury mixer or the like under the above conditions.
  • a kneading method may be used.
  • the treatment temperature T is more preferably in the range of 90 to 180 ° C, still more preferably 100 to 170 ° C. If the treatment temperature T is less than 50 ° C., even if the treatment time is sufficiently long, it is difficult to obtain the above effect. If the treatment temperature T exceeds 200 ° C., the main chain of natural rubber may be decomposed. On the other hand, if the treatment time t (min) is in a range satisfying the above formula, a heat-treated master batch that provides a rubber composition having sufficient low heat buildup and wear resistance can be obtained.
  • the rubber composition of the present invention contains natural rubber and carbon black and / or silica as a reinforcing filler, and has a ratio of ⁇ 30 ° C. tan ⁇ / 60 ° C. tan ⁇ , “CTAB ⁇ A” (reinforcing filler The total surface area) is prepared by taking the above-mentioned various means so as to satisfy the relationship of the formula (1).
  • natural rubber and carbon black may be used in the form of a wet masterbatch, or natural rubber and carbon black and / or silica may be used in the heat treatment masterbatch (dry masterbatch) described above. (Batch) may be used.
  • modified natural rubber can be used as the natural rubber.
  • a compounding agent for the rubber composition at least one compound selected from the aforementioned compound serving as a rubber-filler coupling agent, a nitrosoquinoline compound, a hydrazide compound, and a QAB compound having a dipolar nitrogen-containing portion is used. Can be used.
  • vulcanizing agents other than sulfur for example, vulcanizing agents other than sulfur, vulcanization accelerators, silane coupling agents, process oils, plasticizers, An anti-aging agent, an anti-scorch agent, zinc white, stearic acid and the like can be contained.
  • the vulcanization accelerator that can be used in the present invention is not particularly limited, and examples thereof include M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), and CZ (N-cyclohexyl-2-benzothiazyl).
  • Sulfenamide) and other guanidine vulcanization accelerators such as DPG (diphenylguanidine) can be used, and the amount used is 0.1-5. 0 parts by mass is preferable, and 0.2 to 3.0 parts by mass is more preferable.
  • examples of the process oil used as a softening agent that can be used in the rubber composition of the present invention include paraffinic, naphthenic, and aromatic oils. Aromatics are used for applications that emphasize tensile strength and wear resistance, and naphthenic or paraffinic systems are used for applications that emphasize hysteresis loss and low-temperature characteristics.
  • the amount used is preferably 0 to 100 parts by mass with respect to 100 parts by mass of natural rubber, and if it is 100 parts by mass or less, the deterioration of the tensile strength and low heat build-up (low fuel consumption) of the vulcanized rubber is suppressed. can do.
  • examples of the anti-aging agent that can be used in the rubber composition of the present invention include 3C (N-isopropyl-N′-phenyl-p-phenylenediamine), 6C [N- (1,3-dimethylbutyl) -N ′. -Phenyl-p-phenylenediamine], AW (6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline), high-temperature condensate of diphenylamine and acetone, and the like.
  • the amount to be used is preferably 0.1 to 6.0 parts by mass, more preferably 0.3 to 5.0 parts by mass with respect to 100 parts by mass of natural rubber.
  • the rubber composition of the present invention can be prepared by kneading the above components using a kneader such as an open kneader such as a roll or a closed kneader such as a Banbury mixer.
  • a kneader such as an open kneader such as a roll or a closed kneader such as a Banbury mixer.
  • components other than zinc white, vulcanization accelerator and vulcanizing agent are kneaded in the first stage, and then the remaining zinc white and vulcanized are added to the kneaded product. It is preferable to prepare by adding an accelerator and a vulcanizing agent and kneading in the second stage.
  • the rubber composition of the present invention thus obtained has excellent low heat buildup and excellent wear resistance, and can be used for tire members of large heavy duty tires and off-the-road tires. Examples of the tire member include tread rubber and case rubber including a sidewall.
  • the tire of the present invention is characterized by using the above-described rubber composition of the present invention for a tire member.
  • the tire member include a case rubber including a tread rubber and a sidewall.
  • the rubber composition of the present invention can be used for any of these, and it is particularly preferable to use the rubber composition for the tread rubber.
  • a tire using the rubber composition of the present invention as a case rubber including a tread rubber and a sidewall has low rolling resistance and excellent fuel efficiency, and excellent wear resistance, and is particularly suitable as a large heavy duty tire or an off-the-road tire. It is.
  • gas with which the tire of the present invention is filled normal or air with a changed oxygen partial pressure, or an inert gas such as nitrogen is exemplified.
  • the rubber composition of the present invention is used for a tread, for example, it is extruded on a tread member, and is pasted and molded by a usual method on a tire molding machine to form a raw tire.
  • the green tire is heated and pressed in a vulcanizer to obtain a tire.
  • CTAB cetyltrimethylammonium bromide adsorption specific surface area
  • tan ⁇ were measured in the vulcanized rubber composition, and the ratio of ⁇ 30 ° C. tan ⁇ / 60 ° C. tan ⁇ was determined.
  • Production Example 1 Production of wet masterbatch of natural rubber and carbon black
  • carbon black carbon black species shown in Table 2
  • 95 were used in a homomixer (High Shear mixer manufactured by Silverson). Mass% water was added and finely dispersed to obtain an aqueous dispersion slurry of carbon black.
  • the volume average particle size (mv) was 25 ⁇ m or less
  • the 90 volume% particle size (D90) was 30 ⁇ m or less.
  • the aqueous dispersion slurry of carbon black and the natural rubber latex are stirred in a homomixer so that the mass part of the carbon black in Table 2 is 100 parts by mass of the natural rubber component in the natural rubber latex. After mixing, this was adjusted to pH 4.5 with formic acid and solidified to obtain each wet masterbatch.
  • Example 2 Production of dry masterbatch Untreated natural rubber or modified natural rubber and carbon black of the type and content shown in Table 2 were kneaded in a Banbury mixer as in the first stage shown in Table 1. A dry masterbatch was obtained. In Example 5 and Comparative Example 11, a dry masterbatch was prepared using untreated natural rubber, and in Example 12 using modified natural rubber.
  • Production Example 4 Heat treatment method of master batch A wet master batch or a dry master batch was heat-treated in an oven at a temperature of 140 ° C for 30 minutes.
  • Production Example 5 Production of Rubber-Filler Coupling Agent A mixture was prepared by adding 20 g (65 mmol) of 2,2′-dithio-bis (benzoic acid) to 28.6 mL (390 mmol) of thionyl chloride. The mixture was refluxed for 12 hours and then filtered. The filtrate was dried using a rotary evaporator to obtain 15.0 g (44 mmol) of 2,2′-dithio-bis (benzoyl chloride) powder. The yield of this reaction was 68%. Next, the obtained 2,2′-dithio-bis (benzoyl chloride) was added to 300 mL of chloroform and mixed.
  • Examples 1 to 15 and Comparative Examples 1 to 11 According to the formulation shown in Table 1, natural rubber in the form shown in Table 2, carbon black of the type and amount shown in Table 2, or a combination of carbon black and silica, and rubber-filler shown in Table 2 Twenty-six types of rubber compositions were prepared using a coupling agent. The rubber composition was prepared by first kneading each component of the first stage shown in Table 1 in a Banbury mixer, and then adding each component of the second stage shown in Table 1 to the obtained kneaded product. In addition, it was carried out by kneading. Each rubber composition was vulcanized at 150 ° C. for 90 minutes to prepare a test piece for measuring ⁇ 30 ° C.
  • FIG. 1 is a plot diagram showing the relationship between x and ⁇ 30 ° C. tan ⁇ / 60 ° C. tan ⁇ ratio in the formula (1) in the rubber compositions obtained in Examples and Comparative Examples, and FIG. In the tire obtained by the comparative example, it is a plot figure which shows the relationship between the internal temperature change in a driving
  • Untreated natural rubber or treated natural rubber Untreated natural rubber is ordinary natural rubber, which is obtained by directly coagulating and drying natural rubber latex. The natural rubber and the modified natural rubber in the wet masterbatch or the dry masterbatch shown in FIG. 2) Carbon black: types and amounts are shown in Table 2. 3) Silica: Types and amounts are shown in Table 2.
  • Rubber-filler coupling agent bis [2- (2-oxazolyl) phenyl] disulfide obtained in Production Example 5 5) Silane coupling agent: bis (3-triethoxysilylpropyl) tetrasulfide, Degussa Product name "Si69” 6) Anti-aging agent 6C: N- (1,3-dimethylbutyl) -N′-phenyl-p-phenylenediamine, manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name “NOCRACK 6C” 7) Vulcanization accelerator CZ: N-cyclohexyl-2-benzothiazolylsulfenamide, manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name “Noxeller CZ”
  • the tire temperature using the rubber composition obtained in the example is compared with the tire wear resistance using the rubber composition obtained in the comparative example.
  • the tire using the rubber composition obtained in the examples has good wear resistance.
  • the rubber composition of the present invention can give a tire having both low heat buildup and wear resistance, particularly a large tire such as an off-the-road tire.

Abstract

L'invention porte sur une composition de caoutchouc qui comprend du caoutchouc naturel et, comme charge renforçante, du noir de carbone et/ou de la silice et qui a été ajustée de façon à satisfaire à la relation (1) : tanδ à -30ºC/tanδ à 60ºC > -1026,5Ln(x) + 10256 (1) dans laquelle x = CTAB×A, où CTAB est la surface spécifique (m2/g) de la charge renforçante telle que déterminée par adsorption de bromure de cétyltriméthylammonium conformément à la norme ISO 6810, A est la quantité en partie en masse de la charge renforçante pour 100 parties en masse du caoutchouc naturel et x est un nombre dans la plage de 2 500-13 000 ; Ln(x) désigne le logarithme népérien de x ; et tanδ désigne la tangente de l'angle de perte de la composition de caoutchouc vulcanisée. L'invention porte également sur un pneu qui comprend un élément de pneu obtenu à partir de la composition de caoutchouc. La composition de caoutchouc donne un pneu combinant une faible accumulation de chaleur avec une résistance à l'usure, en particulier un pneu large tel qu'un pneu pour des véhicules tout-terrain. Le pneu, qui comprend un élément de pneu obtenu à partir de la composition de caoutchouc, présente de telles performances.
PCT/JP2010/059706 2009-06-10 2010-06-08 Composition de caoutchouc et pneu obtenu à l'aide de celle-ci WO2010143633A1 (fr)

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WO2015174461A1 (fr) * 2014-05-14 2015-11-19 横浜ゴム株式会社 Composition de caoutchouc pour bande transporteuse et bande transporteuse

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WO1993019578A2 (fr) * 1993-07-14 1993-10-14 Bridgestone Corporation Composition de caoutchouc pour bande de roulement de pneumatique
JP2001294711A (ja) * 2000-04-11 2001-10-23 Yokohama Rubber Co Ltd:The ゴム組成物
JP2006152212A (ja) * 2004-12-01 2006-06-15 Bridgestone Corp 重荷重用空気入りタイヤ
JP2006213804A (ja) * 2005-02-03 2006-08-17 Bridgestone Corp ゴム組成物
JP2006241297A (ja) * 2005-03-03 2006-09-14 Yokohama Rubber Co Ltd:The ゴム組成物
WO2009072413A1 (fr) * 2007-12-03 2009-06-11 Bridgestone Corporation Procédé de fabrication d'un mélange maître de caoutchouc naturel, mélange maître de caoutchouc naturel, composition du caoutchouc et pneu
WO2010055919A1 (fr) * 2008-11-13 2010-05-20 株式会社ブリヂストン Compositions de caoutchouc et pneus

Cited By (8)

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Publication number Priority date Publication date Assignee Title
FR2980206A1 (fr) * 2011-09-19 2013-03-22 Michelin Soc Tech Bande de roulement de pneumatique hors la route
WO2013041401A1 (fr) * 2011-09-19 2013-03-28 Compagnie Generale Des Etablissements Michelin Bande de roulement de pneumatique hors la route
WO2015170669A1 (fr) * 2014-05-08 2015-11-12 株式会社ブリヂストン Composition de caoutchouc et pneu obtenu à l'aide de celle-ci
JP2015214626A (ja) * 2014-05-08 2015-12-03 株式会社ブリヂストン ゴム組成物及びこれを用いてなるタイヤ
US9834658B2 (en) 2014-05-08 2017-12-05 Bridgestone Corporation Rubber composition and tire obtained using same
WO2015174461A1 (fr) * 2014-05-14 2015-11-19 横浜ゴム株式会社 Composition de caoutchouc pour bande transporteuse et bande transporteuse
JPWO2015174461A1 (ja) * 2014-05-14 2017-04-20 横浜ゴム株式会社 コンベヤベルト用ゴム組成物およびコンベヤベルト
US9752018B2 (en) 2014-05-14 2017-09-05 The Yokohama Rubber Co., Ltd. Rubber composition for conveyor belt, and conveyor belt

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