CN118043382A - Masterbatch, method for producing masterbatch, rubber composition for tire, method for producing rubber composition for tire, and rubber material for tire - Google Patents
Masterbatch, method for producing masterbatch, rubber composition for tire, method for producing rubber composition for tire, and rubber material for tire Download PDFInfo
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- CN118043382A CN118043382A CN202280066561.4A CN202280066561A CN118043382A CN 118043382 A CN118043382 A CN 118043382A CN 202280066561 A CN202280066561 A CN 202280066561A CN 118043382 A CN118043382 A CN 118043382A
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- 229920001971 elastomer Polymers 0.000 title claims abstract description 169
- 239000005060 rubber Substances 0.000 title claims abstract description 169
- 239000000203 mixture Substances 0.000 title claims abstract description 109
- 239000004594 Masterbatch (MB) Substances 0.000 title claims abstract description 88
- 239000000463 material Substances 0.000 title claims abstract description 71
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 28
- 229910002011 hydrophilic fumed silica Inorganic materials 0.000 claims abstract description 112
- 229920003244 diene elastomer Polymers 0.000 claims abstract description 72
- 238000004898 kneading Methods 0.000 claims abstract description 50
- 239000006087 Silane Coupling Agent Substances 0.000 claims abstract description 48
- 238000000034 method Methods 0.000 claims abstract description 21
- 230000008569 process Effects 0.000 claims abstract description 10
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 45
- 239000000314 lubricant Substances 0.000 claims description 19
- 238000004132 cross linking Methods 0.000 claims description 8
- 244000043261 Hevea brasiliensis Species 0.000 claims description 7
- 229920003052 natural elastomer Polymers 0.000 claims description 7
- 229920001194 natural rubber Polymers 0.000 claims description 7
- 230000008961 swelling Effects 0.000 claims description 7
- 229920003049 isoprene rubber Polymers 0.000 claims description 4
- 238000005299 abrasion Methods 0.000 abstract description 32
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 119
- 239000000377 silicon dioxide Substances 0.000 description 43
- 238000002156 mixing Methods 0.000 description 33
- 229910021485 fumed silica Inorganic materials 0.000 description 32
- 238000012360 testing method Methods 0.000 description 26
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 24
- 239000006229 carbon black Substances 0.000 description 19
- 239000003921 oil Substances 0.000 description 17
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 16
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 13
- 230000002209 hydrophobic effect Effects 0.000 description 13
- 239000011593 sulfur Substances 0.000 description 13
- 229910052717 sulfur Inorganic materials 0.000 description 13
- 238000002474 experimental method Methods 0.000 description 12
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- 229910052757 nitrogen Inorganic materials 0.000 description 12
- 238000001179 sorption measurement Methods 0.000 description 12
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- 235000021355 Stearic acid Nutrition 0.000 description 9
- 239000004615 ingredient Substances 0.000 description 9
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 9
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 9
- 238000012545 processing Methods 0.000 description 9
- 239000012763 reinforcing filler Substances 0.000 description 9
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- 238000005096 rolling process Methods 0.000 description 8
- 239000011787 zinc oxide Substances 0.000 description 8
- 239000003795 chemical substances by application Substances 0.000 description 7
- 238000013329 compounding Methods 0.000 description 7
- IUJLOAKJZQBENM-UHFFFAOYSA-N n-(1,3-benzothiazol-2-ylsulfanyl)-2-methylpropan-2-amine Chemical compound C1=CC=C2SC(SNC(C)(C)C)=NC2=C1 IUJLOAKJZQBENM-UHFFFAOYSA-N 0.000 description 6
- 230000000704 physical effect Effects 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 125000005372 silanol group Chemical group 0.000 description 6
- 239000002904 solvent Substances 0.000 description 6
- 238000004073 vulcanization Methods 0.000 description 6
- 230000003712 anti-aging effect Effects 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- 235000010724 Wisteria floribunda Nutrition 0.000 description 4
- 230000032683 aging Effects 0.000 description 4
- SKOLWUPSYHWYAM-UHFFFAOYSA-N carbonodithioic O,S-acid Chemical compound SC(S)=O SKOLWUPSYHWYAM-UHFFFAOYSA-N 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- CBXRMKZFYQISIV-UHFFFAOYSA-N 1-n,1-n,1-n',1-n',2-n,2-n,2-n',2-n'-octamethylethene-1,1,2,2-tetramine Chemical compound CN(C)C(N(C)C)=C(N(C)C)N(C)C CBXRMKZFYQISIV-UHFFFAOYSA-N 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- TXDNPSYEJHXKMK-UHFFFAOYSA-N sulfanylsilane Chemical compound S[SiH3] TXDNPSYEJHXKMK-UHFFFAOYSA-N 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 239000006057 Non-nutritive feed additive Substances 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 2
- 239000010692 aromatic oil Substances 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
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- -1 nipsilAQ Chemical compound 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
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- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- VTHOKNTVYKTUPI-UHFFFAOYSA-N triethoxy-[3-(3-triethoxysilylpropyltetrasulfanyl)propyl]silane Chemical compound CCO[Si](OCC)(OCC)CCCSSSSCCC[Si](OCC)(OCC)OCC VTHOKNTVYKTUPI-UHFFFAOYSA-N 0.000 description 2
- DNIAPMSPPWPWGF-VKHMYHEASA-N (+)-propylene glycol Chemical compound C[C@H](O)CO DNIAPMSPPWPWGF-VKHMYHEASA-N 0.000 description 1
- YPFDHNVEDLHUCE-UHFFFAOYSA-N 1,3-propanediol Substances OCCCO YPFDHNVEDLHUCE-UHFFFAOYSA-N 0.000 description 1
- 229940035437 1,3-propanediol Drugs 0.000 description 1
- IABJHLPWGMWHLX-UHFFFAOYSA-N 3-(1,3-benzothiazol-2-yl)propyl-trimethoxysilane Chemical compound C1=CC=C2SC(CCC[Si](OC)(OC)OC)=NC2=C1 IABJHLPWGMWHLX-UHFFFAOYSA-N 0.000 description 1
- DCQBZYNUSLHVJC-UHFFFAOYSA-N 3-triethoxysilylpropane-1-thiol Chemical compound CCO[Si](OCC)(OCC)CCCS DCQBZYNUSLHVJC-UHFFFAOYSA-N 0.000 description 1
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 1
- 229920002943 EPDM rubber Polymers 0.000 description 1
- 241001441571 Hiodontidae Species 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 239000005062 Polybutadiene Substances 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000003679 aging effect Effects 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
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- 239000000498 cooling water Substances 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
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- 239000011707 mineral Substances 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229920001084 poly(chloroprene) Polymers 0.000 description 1
- 229920002857 polybutadiene Polymers 0.000 description 1
- 229920000166 polytrimethylene carbonate Polymers 0.000 description 1
- 239000011164 primary particle Substances 0.000 description 1
- JPPLPDOXWBVPCW-UHFFFAOYSA-N s-(3-triethoxysilylpropyl) octanethioate Chemical compound CCCCCCCC(=O)SCCC[Si](OCC)(OCC)OCC JPPLPDOXWBVPCW-UHFFFAOYSA-N 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 239000005049 silicon tetrachloride Substances 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
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- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 125000003396 thiol group Chemical group [H]S* 0.000 description 1
- FBBATURSCRIBHN-UHFFFAOYSA-N triethoxy-[3-(3-triethoxysilylpropyldisulfanyl)propyl]silane Chemical compound CCO[Si](OCC)(OCC)CCCSSCCC[Si](OCC)(OCC)OCC FBBATURSCRIBHN-UHFFFAOYSA-N 0.000 description 1
- 239000004636 vulcanized rubber Substances 0.000 description 1
Landscapes
- Compositions Of Macromolecular Compounds (AREA)
- Processes Of Treating Macromolecular Substances (AREA)
Abstract
The invention provides a rubber material for a tire with excellent abrasion resistance, a master batch and a rubber composition for a tire which are suitable for manufacturing the rubber material and the master batch, and manufacturing methods thereof. A master batch comprises, per 100 parts by mass of a diene rubber, 13 to 130 parts by mass of a hydrophilic fumed silica, and 1 to 40 parts by mass of a silane coupling agent. A rubber composition for tires, which comprises, per 100 parts by mass of a diene rubber, 5 to 90 parts by mass of a hydrophilic fumed silica and 1.5 to 30 parts by mass of a silane coupling agent. A process for producing a masterbatch, which comprises a step of kneading a diene rubber, a hydrophilic fumed silica and a silane coupling agent using a kneader.
Description
Technical Field
The present invention relates to a masterbatch, a method for producing the masterbatch, a rubber composition for a tire, a method for producing the rubber composition for a tire, and a rubber material for a tire.
Background
In order to reduce the burden on the environment, there is a demand for improvement in fuel consumption performance of tires for automobiles. In order to improve fuel consumption performance, it is effective to reduce rolling resistance of the tire. As an index of rolling resistance of a tire, a loss tangent tan δ at 60 ℃ obtained by measuring dynamic viscoelasticity of a tire is generally used. The smaller the tan δ at 60 ℃, the smaller the rolling resistance, and the fuel consumption performance improves.
Patent document 1 discloses that wet silica is blended as a filler in a rubber composition for a tire in order to reduce rolling resistance. Further, patent document 2 discloses that the amount and particle diameter of carbon black to be blended as a filler contained in a rubber composition for a tire are adjusted in order to reduce rolling resistance.
In order to sufficiently obtain the effect of reducing the heat generating property of a tire, patent document 3 discloses a rubber composition for a tire having good silica dispersibility.
Further, the automobile tire is heated by frictional heat or the like during running. Therefore, the rubber composition constituting the tire for an automobile is required to be less thermally degraded. Patent document 4 discloses a rubber composition for a tire capable of improving grip performance, fuel consumption performance, friction performance, heat resistance, weather resistance, and the like.
Prior art literature
Patent literature
Patent document 1: japanese patent application laid-open No. 2015-218254
Patent document 2: japanese patent laid-open No. 6-256578
Patent document 3: japanese patent laid-open publication No. 2019-094463
Patent document 4: japanese patent laid-open publication No. 2011-52067
Disclosure of Invention
Problems to be solved by the invention
In tires for automobiles, tires for heavy loads such as trucks and buses are required to have a longer running life than tires for passenger cars. Therefore, for heavy duty tires, not only fuel consumption performance and heat resistance but also high abrasion resistance are required.
However, when the rubber composition for a tire containing wet silica described in patent document 1 is used for a heavy-duty tire, there is a problem in that the abrasion resistance is remarkably reduced.
Further, even when the rubber composition for tires containing carbon black described in patent document 2 is used for a heavy-duty tire, there are problems such as a decrease in mechanical properties such as tensile breaking strength, tensile breaking elongation, and rubber hardness, a decrease in abrasion resistance, and a decrease in uneven wear resistance of the tire.
The present invention has been made in view of such circumstances, and an object thereof is to provide a rubber material for a tire excellent in abrasion resistance, a masterbatch suitable for production thereof, a rubber composition for a tire, and a method for producing the same.
Solution for solving the problem
The present inventors have found that a rubber material for a tire excellent in abrasion resistance can be obtained by blending hydrophilic fumed silica as a filler for a rubber composition for a tire instead of carbon black and wet silica.
However, the following insights were obtained: since the hydrophilic fumed silica has a larger volume than the wet silica, scattering of the hydrophilic fumed silica is likely to occur during kneading in a banbury mixer that is generally used for kneading rubber compositions, and it is difficult to obtain a rubber composition in which the hydrophilic fumed silica is sufficiently dispersed.
Based on this finding, the present inventors have further studied and as a result, have found that the above finding can be solved by using a mixer having a low rotor rotation speed which is not normally used for kneading a rubber composition from the problem of productivity.
According to the above, the scheme of the invention is as follows.
[1] A master batch comprises, per 100 parts by mass of a diene rubber, 13 to 130 parts by mass of a hydrophilic fumed silica, and 1 to 40 parts by mass of a silane coupling agent.
[2] The masterbatch according to [1], wherein the BET specific surface area of the hydrophilic fumed silica is 50m 2/g or more and 500m 2/g or less.
[3] The master batch according to [1] or [2], wherein the diene rubber is at least one selected from the group consisting of natural rubber and isoprene rubber.
[4] The master batch according to any one of [1] to [3], which contains 1 to 40 parts by mass of a lubricant per 100 parts by mass of the diene rubber.
[5] A process for producing a masterbatch, which comprises a step of kneading a diene rubber, a hydrophilic fumed silica and a silane coupling agent using a kneader.
[6] The method for producing a masterbatch according to [5], wherein the BET specific surface area of the hydrophilic fumed silica is 50m 2/g or more and 500m 2/g or less.
[7] The method for producing a master batch according to [5] or [6], wherein a lubricant is further kneaded.
[8] A rubber composition for tires, which comprises, per 100 parts by mass of a diene rubber, 5 to 90 parts by mass of a hydrophilic fumed silica and 1.5 to 30 parts by mass of a silane coupling agent.
[9] The rubber composition for a tire according to [8], wherein the BET specific surface area of the hydrophilic fumed silica is 50m 2/g or more and 500m 2/g or less.
[10] The rubber composition for a tire as described in [8] or [9], wherein the masterbatch according to any one of [1] to [4] is contained.
[11] A process for producing a rubber composition for a tire, comprising the step of kneading the master batch according to any one of [1] to [4] with a diene rubber.
[12] A rubber material for tires having an A hardness of 55 to 72 and a crosslinking density of 4X 10 －5 mol/mL or more and less than 27.5X 10 －5 mol/mL by a toluene swelling method.
[13] The rubber material for a tire according to [12], which is obtained by vulcanizing the rubber composition for a tire according to any one of [8] to [10 ].
Effects of the invention
According to the present invention, it is possible to provide a rubber material for a tire excellent in abrasion resistance, a masterbatch suitable for production thereof, a rubber composition for a tire, and a method for producing the same.
Drawings
Fig. 1 is a process diagram of a method for producing a master batch according to the present embodiment.
Fig. 2 is a process diagram of a method for producing a rubber material for a tire using a master batch according to the present embodiment.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments in the following order.
1. Masterbatch
1.1. Diene rubber
1.2. Hydrophilic fumed silica
1.3. Silane coupling agent
1.4. Other ingredients
2. Method for producing master batch
2.1. Kneading machine
2.2. Mixing process
3. Rubber composition for tire
4. Method for producing rubber composition for tire
5. Rubber material for tire
(1. Master batch)
The master batch of the present embodiment is a kneaded material used for obtaining a rubber material, and includes a diene rubber, hydrophilic fumed silica, and a silane coupling agent.
(1.1. Diene rubber)
The diene rubber contained in the masterbatch according to the present embodiment is exemplified by: natural rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, butyl rubber, ethylene-propylene-diene rubber, chloroprene rubber, and the like. Among them, at least one selected from natural rubber and isoprene rubber is preferable.
(1.2. Hydrophilic fumed silica)
Fumed silica is particulate silica produced by high temperature hydrolysis of silicon tetrachloride in oxyhydrogen flame. Therefore, unlike the method for producing wet silica, the primary particle size of the primary agglomerate (minimum constituent) is smaller than that of wet silica, and the BET specific surface area for nitrogen adsorption is larger. The fumed silica particles agglomerate/fuse Cheng Nian beads to form voluminous agglomerates.
Fumed silica is classified into hydrophilic fumed silica and hydrophobic fumed silica based on its property with respect to water. Silanol groups are present on the surface of fumed silica. Silanol groups are chemically reactive and particularly readily react with water. Therefore, a surface treatment (hydrophobizing treatment) may be performed in which silanol groups react with other substances to reduce the reactivity with water. The fumed silica after the hydrophobization treatment is referred to as hydrophobic fumed silica, and the fumed silica without the hydrophobization treatment is referred to as hydrophilic fumed silica.
In the present embodiment, the hydrophobic fumed silica is distinguished from the hydrophilic fumed silica by the modified hydrophobicity (M value) shown below. The modified hydrophobicity (M value) is a value obtained by a measurement method using a case where hydrophobic fumed silica floats in water but is completely suspended in ethanol. As a method for measuring the M value, the method described in the examples of International publication No. 2004/099075 can be used. When the M value is used to represent the hydrophobic fumed silica and the hydrophilic fumed silica, the M value of the hydrophobic fumed silica is 1 or more, and the M value of the hydrophilic fumed silica is less than 1.
The fumed silica contained in the masterbatch according to the present embodiment is hydrophilic fumed silica. As described later, it is considered that hydrophilic fumed silica forms a structure more easily due to fumed silica than hydrophobic fumed silica. Such a structure is considered to exist in a rubber material for a tire obtained by vulcanizing a rubber composition for a tire, and the abrasion resistance of the rubber material for a tire is improved. On the other hand, in the case of the hydrophobic fumed silica, such a structure is small, and the abrasion resistance tends to be insufficient.
In this embodiment, even when the hydrophilic fumed silica is in a large volume state, the hydrophilic fumed silica is sufficiently dispersed in the master batch by a kneading method described later. Therefore, the tap density of the hydrophilic fumed silica is preferably less than 200g/L, more preferably 150g/L or less, and still more preferably 100g/L or less.
In the present embodiment, the tap density of the hydrophilic fumed silica may be 200g/L, but in general, the compression treatment is required to set the tap density of the hydrophilic fumed silica to 200 g/L. Therefore, an additional process is required, and there is a problem of cost.
The lower limit of the tap density of the hydrophilic fumed silica is not particularly limited, but the lower limit of the tap density is, for example, 30g/L from the viewpoint of production.
In the present embodiment, the BET specific surface area of the hydrophilic fumed silica is preferably 50m 2/g or more, 80m 2/g or more, 120m 2/g or more, 200m 2/g or more, 250m 2/g or more, 300m 2/g or more, or 350m 2/g or more. By setting the BET specific surface area of the hydrophilic fumed silica within the above range, the number of silanol groups that become reaction points with the diene rubber or the silane coupling agent in the hydrophilic fumed silica can be sufficiently ensured. As a result, the hydrophilic fumed silica and the diene rubber can be satisfactorily kneaded.
Further, the upper limit of the BET specific surface area of the hydrophilic fumed silica is not particularly limited, and is, for example, 500m 2/g. If the BET specific surface area of the hydrophilic fumed silica is too small, the flame temperature at the time of producing the fumed silica needs to be further increased, and the specific structure of the fumed silica is lost, and the fumed silica tends to be produced in an unstable manner. If the BET specific surface area of the hydrophilic fumed silica is too large, stable production tends to be impossible.
The amount of hydrophilic fumed silica blended in the master batch is 13 parts by mass or more and 130 parts by mass or less relative to 100 parts by mass of the diene rubber. That is, the masterbatch of the present embodiment can contain hydrophilic fumed silica which is difficult to be mixed into the diene rubber and difficult to be dispersed in the diene rubber at a high concentration. Therefore, by using the master batch to produce a rubber composition for a tire, a rubber material for a tire excellent in abrasion resistance can be easily obtained.
The amount of hydrophilic fumed silica blended in the master batch is more preferably 15 parts by mass or more, and still more preferably 20 parts by mass or more, based on 100 parts by mass of the diene rubber. On the other hand, the amount of the hydrophilic fumed silica to be blended is preferably 110 parts by mass or less, more preferably 100 parts by mass or less, based on 100 parts by mass of the diene rubber.
If the amount of the hydrophilic fumed silica blended is too small, the abrasion resistance of the obtained rubber material for a tire tends to be insufficient. If the amount of the hydrophilic fumed silica blended is too large, the hydrophilic fumed silica is not sufficiently dispersed in the diene rubber, and a good kneaded product tends to be not obtained.
(1.3. Silane coupling agent)
The silane coupling agent is contained in the master batch, whereby a crosslinked structure of the hydrophobic diene rubber and the hydrophilic fumed silica is easily formed by the silane coupling agent. As a result, the dispersibility of the hydrophilic fumed silica in the masterbatch is improved, and the abrasion resistance of the rubber material for a tire can be improved.
The silane coupling agent is not particularly limited as long as it is a silane coupling agent generally used for rubber compositions. In this embodiment, a sulfur-containing silane coupling agent is preferable. Examples of the sulfur-containing silane coupling agent include: bis- (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, 3-trimethoxysilylpropyl benzothiazole tetrasulfide, gamma-mercaptopropyl triethoxysilane, 3-octanoylthiopropyl triethoxysilane, mercapto-thiocarboxylate oligomers, and the like.
In the present embodiment, the silane coupling agent is preferably a blocked mercaptosilane (blocked mercaptosilane) from the viewpoint of heat resistance (heat aging property) of the rubber composition for a tire, and particularly preferably a mercapto-thiocarboxylate oligomer.
The mercapto-thiocarboxylate oligomer is an oligomer of a thiocarboxylate having a mercapto group. Examples of the molecular structure of the thiol-thiocarboxylate oligomer are shown below. In the molecular structure described below, the total (x+y) of the number of repetitions (x) of the bonding unit a and the number of repetitions (y) of the bonding unit B is preferably in the range of 3 to 300. If the amount is within this range, since-C 7H15 of the bonding unit A covers the mercaptosilane of the bonding unit B, the scorch time can be suppressed from being shortened, and good reactivity with the hydrophilic fumed silica and the diene rubber can be ensured. As the mercapto-thiocarboxylate oligomer, specifically, "NXT-Z45" by Momentive is exemplified.
The amount of the silane coupling agent blended in the master batch is 1 to 40 parts by mass based on 100 parts by mass of the diene rubber. If the blending amount of the silane coupling agent is too small, the dispersibility of the hydrophilic fumed silica in the rubber composition for a tire tends to be insufficient. If the blending amount of the silane coupling agent is too large, the silane coupling agents tend to be condensed with each other, and the abrasion resistance of the obtained rubber material for a tire tends to be insufficient.
The blending amount of the silane coupling agent in the master batch is preferably 1.5 parts by mass or more, more preferably 2 parts by mass or more, per 100 parts by mass of the diene rubber. On the other hand, the blending amount of the silane coupling agent is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, per 100 parts by mass of the diene rubber.
In addition, in the range of the amount of the silane coupling agent to be incorporated per 100 parts by mass of the diene rubber, it is preferable to relatively increase the amount of the silane coupling agent as the BET specific surface area of the hydrophilic fumed silica becomes larger. This is because the reaction point with the hydrophilic fumed silica can be sufficiently ensured. Specifically, the silane coupling agent is preferably added in the range of 0.33 to 1mg/m 2 relative to the specific surface area of the silica to be added.
In the master batch, by setting the blending amount of the diene rubber, the hydrophilic fumed silica, and the silane coupling agent to a more appropriate range, it is possible to easily obtain a rubber material for a tire that can realize not only good abrasion resistance but also good low fuel consumption performance.
(1.4. Other Components)
In the present embodiment, the master batch may contain components other than the above components (diene rubber, hydrophilic fumed silica, and silane coupling agent) blended into the rubber composition. Examples of such components include lubricants. By including the lubricant in the master batch, the kneading property of the master batch is improved.
As the lubricant, stearic acid and processing oil can be exemplified. The lubricant may be used alone or in combination of two or more. Examples of the processing oil include aromatic oil, paraffinic oil, naphthenic oil, and the like. These may be used alone or in combination of two or more.
The blending amount of the lubricant is not limited in the range where the effects of the present application can be obtained. For example, the blending amount of the lubricant is preferably 1 part by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the diene rubber. The amount of the lubricant to be blended is preferably 2 parts by mass or more, more preferably 3 parts by mass or more, based on 100 parts by mass of the diene rubber. On the other hand, the blending amount of the lubricant is preferably 35 parts by mass or less, more preferably 30 parts by mass or less, per 100 parts by mass of the diene rubber.
If the blending amount of the lubricant is too small, the kneading property of the master batch may be poor, and the abrasion resistance of the obtained rubber material for a tire may not be sufficiently improved. If the blending amount of stearic acid is too large, shearing does not act during kneading, and there is a possibility that the hydrophilic fumed silica cannot be sufficiently dispersed in the diene rubber.
The master batch may contain a reinforcing filler other than the hydrophilic fumed silica. Examples of the reinforcing filler include: carbon black, clay, mica, talc, calcium carbonate, aluminum hydroxide, aluminum oxide, titanium oxide, and the like. In the case of blending a reinforcing filler, a filler coupling agent may be blended in an appropriate amount. The blending amount of the reinforcing filler is not limited to a range in which the effect of the present application can be obtained, and a usual blending amount may be used.
The master batch may contain various additives such as zinc oxide, an anti-aging agent, a plasticizer, a processing aid, a liquid polymer, and a thermosetting resin. The blending amount of these additives is not limited to a range in which the effects of the present application can be obtained, and a usual blending amount may be used.
(2. Method for producing masterbatch)
As shown in fig. 1, the master batch of the present embodiment is obtained by kneading the diene rubber, the hydrophilic fumed silica, the silane coupling agent, and other components as needed.
(2.1. Kneader)
In the present embodiment, the hydrophilic fumed silica is sufficiently dispersed in the master batch so as to sufficiently mix the hydrophilic fumed silica into the diene rubber, and kneading is performed using a kneader.
Conventionally, a banbury mixer has been used to sufficiently disperse silica as a filler in a masterbatch or a rubber composition in order to mix the silica into a diene rubber. The banbury mixer applies a high shear force to raw materials by rotating a rotor at a high speed while pressurizing the raw materials to be mixed by weight. For example, a banbury mixer is useful when wet silica having a high tap density is mixed.
However, when hydrophilic fumed silica having a low tap density and a large volume is mixed into diene rubber using a banbury mixer, the hydrophilic fumed silica is likely to fly as compared with wet silica. Therefore, there is a problem that the amount of the hydrophilic fumed silica actually mixed is smaller than the target blending amount. Further, there is a problem that the hydrophilic fumed silica mixed in tends to agglomerate and not disperse sufficiently in the masterbatch or the rubber composition.
Accordingly, the present inventors have used a kneader to mix hydrophilic fumed silica into diene rubber, thereby suppressing scattering of hydrophilic fumed silica during kneading, and thus obtained a masterbatch in which hydrophilic fumed silica mixed is sufficiently dispersed.
The kneader is one of internal mixers like a Banbury mixer. The difference from a banbury mixer is the rotor speed. From the viewpoint of improving productivity, the rotor speed of the Banbury mixer is usually 45 to 80rpm, whereas the rotor speed of the kneader is 20 to 40rpm.
It is considered that the rotor rotation speed is lower than that of the Banbury mixer, and that the hydrophilic fumed silica having a large volume is not easily scattered during kneading by the kneader, and is sufficiently mixed and dispersed.
It is to be noted that, according to the present inventors, it was confirmed that: even if the mixing is performed by setting the rotor speed of the Banbury mixer to the same level as the rotor speed of the kneader, the hydrophilic fumed silica cannot be sufficiently mixed. This is considered to be because the rotor speed suitable for kneading in the banbury mixer is set in the banbury mixer, and the rotor structure of the banbury mixer is optimized so that kneading proceeds sufficiently in the set rotor speed range.
The kneader may be a pressurized kneader or an open kneader which is not pressurized. In the present embodiment, a pressure kneader is preferable for sufficiently mixing and dispersing the hydrophilic fumed silica. Further, a pressure kneader capable of performing stepwise pressure control is more preferable.
(2.2. Mixing step)
In the kneading step, the diene rubber, the hydrophilic fumed silica, the silane coupling agent, and other components as needed are fed into a kneader and kneaded. The rotor speed was 20-40 rpm as described above. The amount of cooling water is preferably adjusted so that the temperature of the kneaded mixture is in the range of 130 to 160 ℃. In the case of a pressure kneader, the kneading time is preferably about 20 to 60 minutes. The kneading time of the open kneader is preferably longer than that of the pressure kneader. After the completion of kneading, a master batch in which the above components were kneaded was obtained. The master batch is a master batch containing a large volume of hydrophilic fumed silica at a high concentration, which is generally difficult to sufficiently mix and disperse.
(3. Rubber composition for tire)
The rubber composition for a tire of the present embodiment contains a diene rubber, hydrophilic fumed silica, and a silane coupling agent.
In the rubber composition for a tire, the amount of the hydrophilic fumed silica to be blended is 5 parts by mass or more and 90 parts by mass or less relative to 100 parts by mass of the diene rubber. If the amount of the hydrophilic fumed silica blended is too small, the abrasion resistance of the obtained rubber material for a tire tends to be insufficient. If the amount of the hydrophilic fumed silica blended is too large, the hydrophilic fumed silica is not sufficiently dispersed in the diene rubber, and a good kneaded product tends to be not obtained.
The amount of the hydrophilic fumed silica blended in the rubber composition for a tire is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, based on 100 parts by mass of the diene rubber. On the other hand, the amount of hydrophilic fumed silica to be blended is preferably 70 parts by mass or less, more preferably 55 parts by mass or less, per 100 parts by mass of the diene rubber.
The BET specific surface area of the hydrophilic fumed silica is preferably the same as that of the hydrophilic fumed silica contained in the master batch.
The amount of the silane coupling agent blended in the rubber composition for a tire is 1.5 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of the diene rubber. If the blending amount of the silane coupling agent is too small, the dispersibility of the hydrophilic fumed silica in the rubber composition for a tire tends to be insufficient. If the blending amount of the silane coupling agent is too large, the silane coupling agents are likely to condense with each other, and the abrasion resistance of the resulting rubber material for a tire may not be sufficiently improved.
The blending amount of the silane coupling agent in the rubber composition for a tire is preferably 2.0 parts by mass or more, more preferably 2.5 parts by mass or more, based on 100 parts by mass of the diene rubber. On the other hand, the blending amount of the silane coupling agent is preferably 25 parts by mass or less, more preferably 20 parts by mass or less, per 100 parts by mass of the diene rubber.
In the rubber composition for a tire, by setting the blending amount of the diene rubber, the hydrophilic fumed silica and the silane coupling agent to a more appropriate range, it is possible to easily obtain a rubber material for a tire that can realize good abrasion resistance and also good low fuel consumption performance.
The rubber composition for a tire of the present embodiment preferably contains the above-described master batch. That is, the rubber composition for a tire of the present embodiment is preferably produced using the above-described master batch. By using the above-described master batch, a rubber composition for a tire containing a prescribed amount of hydrophilic fumed silica which is difficult to mix and disperse can be easily obtained.
In the present embodiment, the rubber composition for a tire may contain components other than the above components (diene rubber, hydrophilic fumed silica, and silane coupling agent) blended into the rubber composition.
The rubber composition for a tire may also contain a processing oil. Examples of the processing oil include aromatic oil, paraffinic oil, naphthenic oil, and the like. These may be used alone or in combination of two or more. The blending amount of the processing oil is preferably 2 to 10 parts by mass, more preferably 4 to 8 parts by mass, per 100 parts by mass of the diene rubber.
The rubber composition for a tire may contain a reinforcing filler other than the hydrophilic fumed silica. Examples of the reinforcing filler include: carbon black, clay, mica, talc, calcium carbonate, aluminum hydroxide, aluminum oxide, titanium oxide, and the like. In addition, in the case of blending a reinforcing filler, a filler coupling agent may be blended in an appropriate amount. The amount of the reinforcing filler to be blended may be a usual amount within a range that can obtain the effects of the present application.
When carbon black is contained as the reinforcing filler, the amount of carbon black to be blended is, for example, preferably more than 0 parts by mass and 60 parts by mass or less relative to 100 parts by mass of the diene rubber.
The rubber composition for a tire may contain wet silica as a filler. Wet silica is silica that is typically synthesized by the neutralization of sodium silicate with mineral acid (typically sulfuric acid). Wet silica is broadly classified into precipitated silica and gel silica. In the present embodiment, the wet silica is preferably precipitated silica.
However, in wet silica, the amount of silanol groups adsorbed on the surface is larger than that of fumed silica. The adsorbed water is believed to hinder the formation of crosslinked structures. Therefore, the amount of wet silica required due to the effect of the crosslinked structure by silanol groups is more than that of fumed silica. In other words, when the same effect as that exerted by fumed silica is desired, the amount of the wet silica to be blended is larger than the amount of fumed silica to be blended.
Further, since wet silica has a smaller BET specific surface area than fumed silica, the amount of the wet silica to be blended to achieve the target hardness of the rubber material for a tire tends to be large.
From the above, from the viewpoint of the properties of the rubber material for tire, the amount of the wet silica blended is preferably small. On the other hand, since fumed silica is more expensive than wet silica, it is preferable to contain wet silica from the viewpoint of cost.
When the rubber composition for a tire contains wet silica, the amount of wet silica to be blended may be a usual amount as long as the effects of the present application can be obtained. For example, the amount is preferably more than 0 part by mass and 100 parts by mass or less, more preferably more than 0 part by mass and 60 parts by mass or less, per 100 parts by mass of the diene rubber. The wet silica may be mixed with the fumed silica before the step of kneading with the diene rubber, or may be added in the step of kneading the fumed silica with the diene rubber.
The rubber composition for tires may contain various tire components such as a vulcanizing agent or a crosslinking agent, a vulcanization accelerator, sulfur, zinc oxide, stearic acid, an anti-aging agent, a plasticizer, a processing aid, a liquid polymer, a thermosetting resin, and the like. Such components may be blended before or after kneading the rubber composition for a tire to facilitate vulcanization or crosslinking of the rubber composition for a tire. The blending amount of these components for tires may be a usual blending amount within the range that can obtain the effects of the present application. For example, the total amount of sulfur and the vulcanization accelerator is preferably 1.5 parts by mass or more and 7 parts by mass or less per 100 parts by mass of the diene rubber.
The rubber composition for a tire of the present embodiment is excellent in abrasion resistance and therefore suitable for a heavy-duty tire or tread thereof.
(4. Process for producing rubber composition for tire)
As shown in fig. 2, the rubber composition for a tire is preferably obtained by kneading the master batch, the diene rubber, and the above components as needed. That is, in the present embodiment, the rubber composition for a tire is preferably produced by blending other components into a masterbatch. In addition, a diene rubber is blended in addition to the diene rubber contained in the master batch. On the other hand, hydrophilic fumed silica is sufficiently contained in the master batch and therefore is not blended.
In the above-described method for producing a masterbatch, kneading is performed using a kneader, but a kneader used for kneading the rubber composition for a tire is not particularly limited. That is, a Banbury mixer may be used, or a kneader may be used. Since the hydrophilic fumed silica is kneaded using a sufficiently mixed and sufficiently dispersed master batch, even if the hydrophilic fumed silica is kneaded using a Banbury mixer, a well dispersed state of the hydrophilic fumed silica is maintained as it is, and a kneaded product (rubber composition for a tire) is obtained. The kneading may be performed by using a kneader, but from the viewpoint of improving productivity, the kneading is preferably performed by using a Banbury mixer.
The kneading conditions may be those sufficient to knead the master batch and the components.
The rubber composition for a tire may be produced without using a master batch. In this case, as described above, since the volume of the hydrophilic fumed silica is large, a kneader is used to manufacture the rubber composition for a tire. The rubber composition for a tire may be produced by kneading all the components simultaneously in a kneader, or the rubber composition for a tire may be produced by adding the components in stages.
(5. Rubber Material for tire)
The rubber material for a tire of the present embodiment is a material obtained by vulcanizing a rubber composition for a tire.
The tire rubber material has an a hardness adjusted to be in the range of 55 to 72 so as to be suitable for the hardness of the tire. The rubber material for a tire generally containing carbon black and wet silica as a filler has a structure in which rubber and carbon black or silica are crosslinked with sulfur, a structure in which rubber and carbon black or silica are crosslinked with a silane coupling agent, and the like. As a result, the a hardness of the rubber material for a tire is generally proportional to the crosslink density.
The rubber material for a tire of the present embodiment has an a hardness in the range of 55 to 72, and a crosslinking density by a toluene swelling method in the range of 4.0X10 －5 mol/mL or more and less than 27.5X10 －5 mol/mL.
The rubber material for a tire of the present embodiment contains hydrophilic fumed silica derived from the rubber composition for a tire. In the rubber material for tires, it is considered that a structure derived from hydrophilic fumed silica exists in addition to a structure in which diene rubber is crosslinked with hydrophilic fumed silica by sulfur and a structure in which diene rubber is crosslinked with hydrophilic fumed silica by a silane coupling agent, and this structure is considered to contribute to a hardness.
On the other hand, in the toluene swelling method, which is a method of measuring the crosslinking density, it is considered that the structure in which the rubber and the hydrophilic fumed silica are crosslinked with sulfur and the structure in which the rubber and the hydrophilic fumed silica are crosslinked with a silane coupling agent are not dissolved in toluene, whereas the structure due to the hydrophilic fumed silica is dissolved in toluene. As a result, this structure contributes to the a hardness, but is not reflected in the measurement of the crosslink density. Therefore, it is considered that the rubber material for a tire of the present embodiment has an a hardness in the range of 55 to 72 and a crosslinking density by the toluene swelling method is lower than that of a rubber material for a tire in which carbon black, wet silica or the like is blended.
It is considered that when stress is applied to the rubber material for a tire, the structure is separated or connected, and as a result, the stress is dispersed, and the abrasion resistance of the rubber material for a tire is improved.
It is to be noted that, according to the present inventors, it was confirmed that: in the case of hydrophobic fumed silica, the above effect becomes small.
The crosslinking density is preferably 27.1X10 －5 mol/mL or less. The crosslinking density is preferably 6X 10 －5 mol/mL or more.
The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and may be modified in various ways within the scope of the present invention.
The rubber material for a tire is excellent in abrasion resistance, and therefore can be applied to various parts of a tire. Among them, it is applicable to treads, base treads, side walls, grippers (clinch), and the like. The vehicle to which the rubber material for a tire of the present invention can be applied is not particularly limited, but can be applied to cars, trucks and buses requiring abrasion resistance, heavy machinery for construction, EV (ELECTRIC VEHICLE: electric automobile), and low-pollution vehicles (eco car) which should cope with global environmental protection.
Examples
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.
(Experiment 1)
(Preparation of master batch)
The following ingredients were charged into a pressure kneader having a volume of 0.5L so that the compounding amounts with respect to 100 parts by mass of the diene rubber became the compounding amounts shown in table 1. After the kneading was performed, the mixture was kneaded at a rotor rotation speed of 20 to 40rpm for about 30 minutes so that the temperature of the kneaded mixture was in the range of 130 to 160 ℃. The cylinder pressure was 0.7MPa. After the completion of kneading, the mixture was cooled to room temperature, and the kneaded product was taken out to obtain a master batch.
(A) Diene rubber
(A-1) Vietnam Natural rubber: SVR.
(B) Filler (B)
(B-1) hydrophilic fumed silica (manufactured by Deshan, reolosilQS-30C, nitrogen adsorption BET specific surface area: 300m 2/g, tap density: 100 g/L).
(B-2) hydrophobic fumed silica (manufactured by Deshan, reolosilKS-30SC, nitrogen adsorption BET specific surface area: 230M 2/g, tap density: 100g/L, M value: 55).
(B-3) Wet Silica (manufactured by Tosoh Silica, nipsilAQ, nitrogen adsorption BET specific surface area: 200m 2/g, tap density: 300 g/L).
(B-4) carbon black (TOKAI CARBON, seast, nitrogen-adsorbing BET specific surface area: 120m 2/g, tap density: 400 g/L).
(C) Silane coupling agent
(C-1) thiol-thiocarboxylate oligomer (manufactured by Momentive, NXT-Z45).
(C-2) bis- (3-triethoxysilylpropyl) tetrasulfide (manufactured by Evonik, si 69).
(D) Other ingredients
(D-1) lubricants (stearic acid, manufactured by Niday oil, beaded stearic acid YR).
(D-2) processing Oil (manufactured by Fuji, AROMAX (TDAE Oil)).
(D-3) processing oil (1, 3-propanediol, fuji film and Wako pure chemical industries, ltd.).
TABLE 1
(Preparation of rubber composition for tire)
The master batch (A-1) obtained and (D-4) and (D-5) shown below were charged into a closed Banbury mixer having a volume of 1.7L. After the kneading was performed, the mixture was kneaded at a rotor rotation speed of 45 to 80rpm for about 10 minutes so that the temperature of the kneaded mixture was in the range of 130 to 160 ℃. The ram pressure during kneading is in the range of 0.5 to 4.0 MPa. After completion of kneading, the mixture was cooled to room temperature to obtain a kneaded product.
To the obtained kneaded material, the following (D-6) and (D-7) were added and mixed by a 6-inch roll tester to obtain a rubber composition for a tire. The blending of the obtained rubber composition for a tire is shown in table 2.
(D) Other ingredients
(D-4) an anti-aging agent (OZONONE C, manufactured by Seikovia chemical Co., ltd.).
(D-5) lubricants (zinc oxide, 3 types of zinc oxide, manufactured by orthochemical).
(D-6) Sulfur (see Crane chemical industry, jinhua stamp-pad ink is added with micro powder sulfur).
(D-7) vulcanization accelerator (N- (tert-butyl) -2-benzothiazole sulfenamide (TBBS), manufactured by SanxinKagaku chemical Co., ltd., SANCELER NS-G).
TABLE 2
Test pieces for evaluation shown below were prepared for the obtained rubber compositions for tires. The following physical properties were evaluated using the obtained test pieces.
(Processability: mooney viscosity)
The Mooney viscosity (ML1+4 at 100 ℃) of the obtained test piece of the rubber composition for a tire was measured by using a Mooney viscometer (VR-1132 manufactured by Shimadzu corporation) in accordance with JISK 6300-1. When the Mooney viscosity is low, the processability of the rubber composition for a tire tends to be good. The results are shown in Table 2.
(Preparation of rubber Material for tire)
Then, the obtained rubber composition for a tire was press-vulcanized at 150℃for 10 minutes to obtain a rubber material for a tire. Test pieces for evaluation shown below were prepared from the obtained rubber materials for tires. The following physical properties were evaluated using the obtained test pieces.
(A hardness)
The hardness (Shore A hardness) of the test piece of the obtained rubber material for a tire was measured by a durometer in accordance with JIS K6253A type. Since the target a hardness of the rubber material for a tire is 65, the a hardness of the test piece is also preferably about 65. The results are shown in Table 2.
(Low Fuel consumption Performance: tan delta at 60 ℃ C.)
The test piece of the obtained rubber material for a tire was measured under the following conditions using a dynamic viscoelasticity tester (VR-7130 manufactured by Shimadzu corporation) in accordance with JIS K6394. Tan delta (60 ℃) was calculated from the measured values at 60 ℃.
Measuring temperature: 60 ℃.
Static strain: 10%.
Dynamic strain: 2%.
Frequency: 10Hz.
The rolling resistance index was calculated by the following equation, assuming that tan δ (60 ℃) of the calculated standard example 1 was 1.0. The larger the index, the more excellent the rolling resistance. The results are shown in Table 2.
(Rolling resistance index) = (tan δ (60 ℃) of Standard example 1)/(tan δ (60 ℃) of examples)
(Wear resistance: FPS wear amount)
The obtained test piece of the rubber material for a tire was subjected to measurement of the amount of FPS abrasion using an FPS abrasion tester (AB-2012 manufactured by Shimadzu corporation) under conditions of 20℃and 40N load, 10% slip ratio, and 2 minutes test time. The loss of volume was calculated from the amount of abrasion of FPS, and the abrasion index was calculated by the following equation, assuming that the amount of loss in standard example 1 was 1.0. The larger the index, the more excellent the abrasion resistance. The results are shown in Table 2.
(Wear resistance index) = (loss amount of standard example 1)/(loss amount of example)
(Crosslink Density: toluene swelling method)
The crosslink density was calculated based on toluene swelling method. First, a test piece of a rubber material for a tire was immersed in toluene at a temperature of 20℃for 48 hours. Then, based on the obtained data, the crosslink density at which the filler is not swollen was calculated based on the following Flory-Rehner formula. The results are shown in Table 2.
Here, "V" in the formula is the molecular capacity (mL/mol) of the solvent, and in this example, "V" is 106.1 since toluene is used as the solvent.
In the formula, "V R" is the volume fraction of the rubber alone in the swollen gel, and is determined according to the following formula.
VR＝VP/(VP+VS)
"V P" is the volume of the rubber alone in the test piece, and is determined according to the following formula.
VP＝(100W1)/(Z×d)
"W1" is the weight of the rubber test piece. "Z" is the sum of the weight ratios of the rubber and the compounding agent in the test piece, and "d" is the density of the rubber.
"V S" is the volume of the solvent absorbed by the test piece, and is determined according to the following formula.
VS＝(W2－W3)/ds
"W2" is the weight of the rubber test piece swollen with toluene, and "W3" is the weight of the rubber test piece after drying and removing toluene. "ds" is the density of the solvent (toluene).
"Mu" is the interaction constant between the rubber and the solvent. In this example, "μ" was 0.39 due to the use of toluene as the solvent.
From table 2, it can be confirmed that: the rubber material for a tire produced by using a masterbatch obtained by kneading hydrophilic fumed silica at a high concentration has higher abrasion resistance than the rubber material for a tire produced by using a masterbatch obtained by kneading carbon black, wet silica or hydrophobic fumed silica.
Further, it can be confirmed that: the crosslink density of the rubber material for tires produced using the masterbatch in which the hydrophilic fumed silica is kneaded at a high concentration is lower than that of the rubber material for tires produced using the masterbatch in which the carbon black, the wet silica or the hydrophobic fumed silica is kneaded.
(Experiment 2)
The following ingredients were charged into a pressure kneader having a volume of 0.5L so that the compounding amounts with respect to 100 parts by mass of the diene rubber became the compounding amounts shown in table 3. After the kneading was performed, the mixture was kneaded at a rotor rotation speed of 20 to 40rpm for about 30 minutes so that the temperature of the kneaded mixture was in the range of 130 to 160 ℃. The cylinder pressure was 0.7MPa. After the completion of kneading, the mixture was cooled to room temperature, and the kneaded product was taken out to obtain a master batch.
(A) Diene rubber
(A-1) Vietnam Natural rubber: SVR.
(B) Filler (B)
(B-1) hydrophilic fumed silica (manufactured by Deshan, reolosilQS-30C, nitrogen adsorption BET specific surface area: 300m 2/g, tap density: 100 g/L).
(B-4) carbon black (TOKAI CARBON, seast, nitrogen-adsorbing BET specific surface area: 120m 2/g, tap density: 400 g/L).
(C) Silane coupling agent
(C-1) thiol-thiocarboxylate oligomer (manufactured by Momentive, NXT-Z45).
(D) Other ingredients
(D-1) lubricants (stearic acid, manufactured by Niday oil, beaded stearic acid YR).
(D-2) processing Oil (manufactured by Fuji, AROMAX (TDAE Oil)).
TABLE 3
(Preparation of rubber composition for tire)
The master batch (A-1) obtained and (D-4) and (D-5) shown below were charged into a closed Banbury mixer having a volume of 1.7L. After the kneading was performed, the mixture was kneaded at a rotor rotation speed of 45 to 80rpm for about 10 minutes so that the temperature of the kneaded mixture was in the range of 130 to 160 ℃. The kneading pressure is in the range of 0.5 to 4.0 MPa. After completion of kneading, the mixture was cooled to room temperature to obtain a kneaded product.
To the obtained kneaded material, the following (D-6) and (D-7) were added, and the mixture was mixed by a 6-inch roll tester to obtain a rubber composition for a tire. The blending of the obtained rubber composition for tires is shown in table 4.
(D) Other ingredients
(D-4) an anti-aging agent (OZONONE C, manufactured by Seikovia chemical Co., ltd.).
(D-5) lubricants (zinc oxide, 3 types of zinc oxide, manufactured by orthochemical).
(D-6) Sulfur (see Crane chemical industry, jinhua stamp-pad ink is added with micro powder sulfur).
(D-7) vulcanization accelerator (N- (tert-butyl) -2-benzothiazole sulfenamide (TBBS), manufactured by SanxinKagaku chemical Co., ltd., SANCELER NS-G).
TABLE 4
Test pieces for evaluating the obtained rubber composition for a tire in the same manner as in experiment 1 were prepared. The physical properties (mooney viscosity) evaluated in experiment 1 were evaluated using the obtained test pieces. The results are shown in Table 4.
(Preparation of rubber Material for tire)
Then, the obtained rubber composition for a tire was press-vulcanized at 150℃for 10 minutes to obtain a rubber material for a tire. From the obtained rubber material for tires, test pieces for evaluation similar to that of experiment 1 were produced. The physical properties (a hardness, low fuel consumption performance, abrasion resistance, and crosslink density) evaluated in experiment 1 were evaluated using the obtained test piece. The results are shown in Table 4. Further, in experiment 2, the heat aging resistance was evaluated as follows for standard example 1 and example 1.
(Thermal aging resistance)
The obtained rubber composition for a tire was vulcanized at 150℃for 20 minutes using a mold having a thickness of 2mm, and the obtained vulcanized rubber sheet was made into a die-cut sample in accordance with JIS No. 3 dumbbell. After the sample was thermally aged in a Gill's oven (geer oven) set at a temperature of 80℃for 7 days (168 hours), the elongation at break was measured with a tensile tester in accordance with JIS K625 1 together with the unaged sample. The ratio of unaged elongation at break (Eb) to aged elongation at break (Ea) was obtained, and Ea/Eb was used as an index of thermal aging resistance. Using the calculated index, the heat resistance index was calculated by the following calculation formula, with the index of standard example 1 being 1. The heat aging resistance is more excellent as the heat resistance index is larger, and the heat aging resistance is poor when the heat resistance index is 105 or less. The results are shown in Table 4.
(Heat resistance index) = { (index of example)/(index of Standard example 1) } ×100
From table 4, it can be confirmed that: the rubber material for tires having a BET specific surface area of 50m 2/g or more has a higher abrasion resistance than the rubber material for tires produced by using a masterbatch obtained by kneading carbon black.
Further, it can be confirmed that: the rubber material for tires having a BET specific surface area of 50m 2/g or more has a high heat aging resistance as compared with the rubber material for tires produced by using a masterbatch obtained by kneading carbon black.
(Experiment 3)
The following ingredients were charged into a pressure kneader having a volume of 0.5L so that the compounding amounts with respect to 100 parts by mass of the diene rubber became the compounding amounts shown in table 5. After the kneading was performed, the mixture was kneaded at a rotor rotation speed of 20 to 40rpm for about 30 minutes so that the temperature of the kneaded mixture was in the range of 130 to 160 ℃. The cylinder pressure was 0.7MPa. After completion of kneading, the mixture was cooled to room temperature, and the kneaded product was taken out to obtain a rubber composition for a tire. That is, in experimental example 3, a rubber composition for a tire was produced without using a master batch.
(A) Diene rubber
(A-1) Vietnam Natural rubber: SVR.
(B) Filler (B)
(B-1) hydrophilic fumed silica (manufactured by Deshan, reolosilQS-30C, nitrogen adsorption BET specific surface area: 300m 2/g, tap density: 100 g/L).
(B-3) Wet Silica (manufactured by Tosoh Silica, nipsilAQ, nitrogen adsorption BET specific surface area: 200m 2/g, tap density: 300 g/L).
(B-4) carbon black (TOKAI CARBON, seast, nitrogen-adsorbing BET specific surface area: 120m 2/g, tap density: 400 g/L).
(B-5) hydrophilic fumed silica (manufactured by Deshan, reolosilQS-10, nitrogen adsorption BET specific surface area: 140m 2/g, tap density: 50 g/L).
(B-6) hydrophilic fumed silica (manufactured by Deshan, reolosilCP-102, nitrogen adsorption BET specific surface area: 200m 2/g, tap density: 50 g/L).
(B-7) hydrophilic fumed silica (manufactured by Deshan, reolosilQS-40, nitrogen adsorption BET specific surface area: 380m 2/g, tap density: 50 g/L).
(B-8) hydrophilic fumed silica (Deshan, experimental sample, nitrogen adsorption BET specific surface area: 420m 2/g, tap density: 50 g/L).
(B-9) hydrophilic fumed silica (Deshan, experimental sample, nitrogen adsorption BET specific surface area: 450m 2/g, tap density: 50 g/L).
(C) Silane coupling agent
(C-1) thiol-thiocarboxylate oligomer (manufactured by Momentive, NXT-Z45).
(D) Other ingredients
(D-1) lubricants (stearic acid, manufactured by Niday oil, beaded stearic acid YR).
(D-2) processing Oil (manufactured by Fuji, AROMAX (TDAE Oil)).
(D-4) an anti-aging agent (OZONONE C, manufactured by Seikovia chemical Co., ltd.).
(D-5) lubricants (zinc oxide, 3 types of zinc oxide, manufactured by orthochemical).
(D-6) Sulfur (see Crane chemical industry, jinhua stamp-pad ink is added with micro powder sulfur).
(D-7) vulcanization accelerator (N- (tert-butyl) -2-benzothiazole sulfenamide (TBBS), manufactured by SanxinKagaku chemical Co., ltd., SANCELER NS-G).
As a method for producing the test samples (B-8) and (B-9), a method described in J.5.1 (1984) of surface science was used. Specifically, the flame temperature is converted into a heat-insulating temperature calculated from the heat generated and the specific heat in the equilibrium state at the time of production of fumed silica, and the heat-insulating temperature is controlled to 1700 to 1800 ℃, whereby hydrophilic fumed silica of (B-8) and (B-9) is produced.
Test pieces for evaluating the obtained rubber composition for a tire in the same manner as in experiment 1 were prepared. The physical properties (mooney viscosity) evaluated in experiment 1 were evaluated using the obtained test pieces. The results are shown in Table 5.
(Preparation of rubber Material for tire)
Then, the obtained rubber composition for a tire was press-vulcanized at 150℃for 10 minutes to obtain a rubber material for a tire. From the obtained rubber material for tires, test pieces for evaluation similar to that of experiment 1 were produced. The physical properties (a hardness, low fuel consumption performance, abrasion resistance, and crosslink density) evaluated in experiment 1 were evaluated using the obtained test piece.
TABLE 5
From table 5, it can be confirmed that: the rubber material for tires, which does not use a base material and contains hydrophilic fumed silica in a high concentration, has higher abrasion resistance than the rubber material for tires produced by using a masterbatch obtained by kneading carbon black or wet silica.
Claims (13)
1. A master batch comprises, per 100 parts by mass of a diene rubber, 13 to 130 parts by mass of a hydrophilic fumed silica, and 1 to 40 parts by mass of a silane coupling agent.
2. The master batch according to claim 1, wherein,
The BET specific surface area of the hydrophilic fumed silica is 50m 2/g or more and 500m 2/g or less.
3. A masterbatch according to claim 1 or 2 wherein,
The diene rubber is at least one selected from the group consisting of natural rubber and isoprene rubber.
4. The masterbatch according to any one of claims 1 to 3, comprising 1 to 40 parts by mass of a lubricant per 100 parts by mass of the diene rubber.
5. A process for producing a masterbatch, which comprises a step of kneading a diene rubber, a hydrophilic fumed silica and a silane coupling agent using a kneader.
6. The method for producing a masterbatch according to claim 5 wherein,
The BET specific surface area of the hydrophilic fumed silica is 50m 2/g or more and 500m 2/g or less.
7. The method for producing a master batch according to claim 5 or 6, wherein,
The lubricant is further kneaded.
8. A rubber composition for tires, which comprises, per 100 parts by mass of a diene rubber, 5 to 90 parts by mass of a hydrophilic fumed silica and 1.5 to 30 parts by mass of a silane coupling agent.
9. The rubber composition for a tire according to claim 8, wherein,
The BET specific surface area of the hydrophilic fumed silica is 50m 2/g or more and 500m 2/g or less.
10. The rubber composition for a tire according to claim 8, wherein,
Comprising a masterbatch according to any one of claims 1 to 4.
11. A process for producing a rubber composition for a tire, comprising the step of kneading the master batch according to any one of claims 1 to 4 with a diene rubber.
12. A rubber material for tires having an A hardness of 55 to 72 and a crosslinking density of 4X 10 － 5 mol/mL or more and less than 27.5X 10 －5 mol/mL by a toluene swelling method.
13. The rubber material for a tire according to claim 12, which is obtained by vulcanizing the rubber composition for a tire according to any one of claims 8 to 10.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2021-162925 | 2021-10-01 | ||
| JP2022101334 | 2022-06-23 | ||
| JP2022-101334 | 2022-06-23 | ||
| PCT/JP2022/036258 WO2023054510A1 (en) | 2021-10-01 | 2022-09-28 | Masterbatch, method for producing masterbatch, rubber composition for tires, method for producing rubber composition for tires, and rubber material for tires |
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| CN118043382A true CN118043382A (en) | 2024-05-14 |
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| CN202280066561.4A Pending CN118043382A (en) | 2021-10-01 | 2022-09-28 | Masterbatch, method for producing masterbatch, rubber composition for tire, method for producing rubber composition for tire, and rubber material for tire |
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| CN (1) | CN118043382A (en) |
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- 2022-09-28 CN CN202280066561.4A patent/CN118043382A/en active Pending
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