WO2023190688A1 - Rubber composition for tires - Google Patents
Rubber composition for tires Download PDFInfo
- Publication number
- WO2023190688A1 WO2023190688A1 PCT/JP2023/012811 JP2023012811W WO2023190688A1 WO 2023190688 A1 WO2023190688 A1 WO 2023190688A1 JP 2023012811 W JP2023012811 W JP 2023012811W WO 2023190688 A1 WO2023190688 A1 WO 2023190688A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- mass
- rubber
- rubber composition
- silica
- butadiene rubber
- Prior art date
Links
- 229920001971 elastomer Polymers 0.000 title claims abstract description 72
- 239000005060 rubber Substances 0.000 title claims abstract description 72
- 239000000203 mixture Substances 0.000 title claims abstract description 69
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 124
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 62
- 229920003048 styrene butadiene rubber Polymers 0.000 claims abstract description 55
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical class C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 claims abstract description 43
- 229920003244 diene elastomer Polymers 0.000 claims abstract description 38
- 239000011256 inorganic filler Substances 0.000 claims abstract description 24
- 229910003475 inorganic filler Inorganic materials 0.000 claims abstract description 24
- 230000009477 glass transition Effects 0.000 claims abstract description 20
- 239000006229 carbon black Substances 0.000 claims abstract description 17
- 125000003011 styrenyl group Chemical group [H]\C(*)=C(/[H])C1=C([H])C([H])=C([H])C([H])=C1[H] 0.000 claims abstract description 12
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 claims description 22
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 claims description 20
- 238000006116 polymerization reaction Methods 0.000 claims description 11
- 229920002554 vinyl polymer Polymers 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 abstract description 5
- 239000003921 oil Substances 0.000 description 29
- 238000005299 abrasion Methods 0.000 description 18
- 230000007774 longterm Effects 0.000 description 18
- 235000019241 carbon black Nutrition 0.000 description 15
- 238000012360 testing method Methods 0.000 description 15
- 150000001875 compounds Chemical class 0.000 description 13
- 230000035882 stress Effects 0.000 description 13
- 238000002156 mixing Methods 0.000 description 11
- 239000005062 Polybutadiene Substances 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 9
- 239000006087 Silane Coupling Agent Substances 0.000 description 8
- 229920002857 polybutadiene Polymers 0.000 description 8
- 238000004073 vulcanization Methods 0.000 description 8
- 244000043261 Hevea brasiliensis Species 0.000 description 7
- -1 amide compounds Chemical class 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 229920003052 natural elastomer Polymers 0.000 description 7
- 229920001194 natural rubber Polymers 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 239000003795 chemical substances by application Substances 0.000 description 6
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 5
- 238000010521 absorption reaction Methods 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 229910052717 sulfur Inorganic materials 0.000 description 5
- 239000011593 sulfur Substances 0.000 description 5
- 229920000459 Nitrile rubber Polymers 0.000 description 4
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 4
- 238000013329 compounding Methods 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 125000000524 functional group Chemical group 0.000 description 4
- 239000004636 vulcanized rubber Substances 0.000 description 4
- 238000004566 IR spectroscopy Methods 0.000 description 3
- 230000032683 aging Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- LZZYPRNAOMGNLH-UHFFFAOYSA-M Cetrimonium bromide Chemical compound [Br-].CCCCCCCCCCCCCCCC[N+](C)(C)C LZZYPRNAOMGNLH-UHFFFAOYSA-M 0.000 description 2
- 239000004593 Epoxy Chemical class 0.000 description 2
- 239000004594 Masterbatch (MB) Substances 0.000 description 2
- 235000021355 Stearic acid Nutrition 0.000 description 2
- 230000003712 anti-aging effect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 239000006232 furnace black Substances 0.000 description 2
- 238000005227 gel permeation chromatography Methods 0.000 description 2
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 2
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 2
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 2
- 239000004014 plasticizer Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 125000005372 silanol group Chemical group 0.000 description 2
- 239000008117 stearic acid Substances 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
- 239000011787 zinc oxide Substances 0.000 description 2
- 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
- XMWRBQBLMFGWIX-UHFFFAOYSA-N C60 fullerene Chemical class C12=C3C(C4=C56)=C7C8=C5C5=C9C%10=C6C6=C4C1=C1C4=C6C6=C%10C%10=C9C9=C%11C5=C8C5=C8C7=C3C3=C7C2=C1C1=C2C4=C6C4=C%10C6=C9C9=C%11C5=C5C8=C3C3=C7C1=C1C2=C4C6=C2C9=C5C3=C12 XMWRBQBLMFGWIX-UHFFFAOYSA-N 0.000 description 1
- 239000006237 Intermediate SAF Substances 0.000 description 1
- 239000006057 Non-nutritive feed additive Substances 0.000 description 1
- 239000004721 Polyphenylene oxide Chemical class 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- FACXGONDLDSNOE-UHFFFAOYSA-N buta-1,3-diene;styrene Chemical compound C=CC=C.C=CC1=CC=CC=C1.C=CC1=CC=CC=C1 FACXGONDLDSNOE-UHFFFAOYSA-N 0.000 description 1
- 229920005549 butyl rubber Polymers 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000006231 channel black Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 229910052570 clay Inorganic materials 0.000 description 1
- 239000007822 coupling agent Substances 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 239000003431 cross linking reagent Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000000113 differential scanning calorimetry Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000010528 free radical solution polymerization reaction Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 229910003472 fullerene Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 229920005555 halobutyl Polymers 0.000 description 1
- 150000002366 halogen compounds Chemical class 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000012948 isocyanate Substances 0.000 description 1
- 150000002513 isocyanates Chemical class 0.000 description 1
- 229920003049 isoprene rubber Polymers 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000010445 mica Substances 0.000 description 1
- 229910052618 mica group Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 150000002921 oxetanes Chemical class 0.000 description 1
- AFEQENGXSMURHA-UHFFFAOYSA-N oxiran-2-ylmethanamine Chemical group NCC1CO1 AFEQENGXSMURHA-UHFFFAOYSA-N 0.000 description 1
- 150000002924 oxiranes Chemical class 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- 229920000570 polyether Chemical class 0.000 description 1
- 229920001296 polysiloxane Chemical class 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229920001021 polysulfide Chemical class 0.000 description 1
- 239000005077 polysulfide Chemical class 0.000 description 1
- 150000008117 polysulfides Chemical class 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 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
- 230000035945 sensitivity Effects 0.000 description 1
- 150000004756 silanes Chemical class 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000005987 sulfurization reaction Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 150000003505 terpenes Chemical class 0.000 description 1
- 235000007586 terpenes Nutrition 0.000 description 1
- 239000006234 thermal black Substances 0.000 description 1
- 238000001757 thermogravimetry curve Methods 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 150000003553 thiiranes Chemical class 0.000 description 1
- 150000003606 tin compounds Chemical class 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 230000007704 transition Effects 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
Classifications
-
- 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
-
- 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
- C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
- C08K3/013—Fillers, pigments or reinforcing additives
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L15/00—Compositions of rubber derivatives
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/80—Technologies aiming to reduce greenhouse gasses emissions common to all road transportation technologies
- Y02T10/86—Optimisation of rolling resistance, e.g. weight reduction
Definitions
- the present invention relates to a rubber composition for tires that further improves the balance between on-snow performance, wet performance, and wear resistance.
- All-season tires are required to have excellent snow performance when driving on snowy roads and wet performance when driving on non-snowy roads (wet roads), as well as excellent wear resistance. If the blending amount of carbon black is increased in order to improve the abrasion resistance of a rubber composition for tires, wet performance, particularly wet grip performance after long-term use, may deteriorate.
- silica is blended into tire rubber compositions to improve wet performance.
- silica compared to carbon black, silica has a problem in that its reinforcing performance is lower when blended with diene rubber, resulting in lower wear resistance.
- the dispersibility of silica decreases, further reducing abrasion resistance, and the rubber composition loses its flexibility, making it difficult to handle on snow. There is a problem that performance deteriorates.
- Patent Documents 1 and 2 propose improving the dispersibility of silica by using a rubber composition in which silica is blended with terminal-modified styrene-butadiene rubber whose terminals are modified with polyorganosiloxane or the like.
- the level of demand that users expect for improvements in on-snow performance, wet performance, and abrasion resistance is higher, and there is a need to further improve these characteristics, especially to maintain wet grip performance after long-term use. .
- An object of the present invention is to provide a rubber composition for tires that improves the balance between on-snow performance, wet performance, and abrasion resistance beyond conventional levels, and maintains wet grip performance after long-term use. be.
- the tire rubber composition of the present invention which achieves the above object contains 30 to 60 mass% of terminally modified styrene-butadiene rubber and 100 parts by mass of a diene rubber having an average glass transition temperature of -70°C to -55°C.
- an inorganic filler containing silica and carbon black 70 parts by mass or more of an inorganic filler containing silica and carbon black is blended, the silica in the inorganic filler is 60 mass% or more, and the terminal-modified styrene-butadiene rubber contains 23 mass% or more of oil extending oil;
- the tire rubber composition of the present invention can improve the balance between on-snow performance, wet performance, and abrasion resistance beyond conventional levels, and can maintain wet grip performance after long-term use.
- the rubber composition for tires preferably has an average vinyl content of 40% by mass or less in the butadiene polymerization component in the diene rubber. Further, it is preferable that the inorganic filler is blended in 70 parts by mass or more and 90 parts by mass or less with 100 parts by mass of the diene rubber, and furthermore, the content of silica in the inorganic filler is preferably 60 mass% or more and 90 mass% or less.
- the rubber component is a diene rubber, and the diene rubber necessarily contains terminally modified styrene-butadiene rubber.
- Terminal-modified styrene-butadiene rubber is styrene-butadiene rubber that has a functional group at one or both ends of its molecular chain.
- the terminal-modified styrene-butadiene rubber is preferably a modified rubber having a functional group at the terminal of styrene-butadiene rubber produced by solution polymerization.
- the functional group possessed by the terminal-modified styrene-butadiene rubber is preferably a functional group derived from a compound that reacts with the silanol group on the surface of the silica.
- Compounds that react with this silanol group are not particularly limited, but include, for example, polyorganosiloxane compounds, epoxy compounds, hydrocarbyloxysilicon compounds, tin compounds, silicon compounds, silane compounds, amide compounds and/or imide compounds, and isocyanates.
- the terminally modified styrene-butadiene rubber has a styrene unit content of 37% by mass or less, preferably 20 to 37% by mass, more preferably 27 to 37% by mass.
- a styrene unit content of the terminal-modified styrene-butadiene rubber can be measured by infrared spectroscopy (Hampton method).
- the vinyl unit content of the terminal-modified styrene-butadiene rubber is preferably 20 to 45% by mass, more preferably 35 to 45% by mass.
- Tg glass transition temperature
- the vinyl unit content of the terminal-modified styrene-butadiene rubber is less than 20% by mass, the Tg of the terminal-modified styrene-butadiene rubber may become low, and wet grip performance may deteriorate. Furthermore, if the vinyl unit content of the terminal-modified styrene-butadiene rubber exceeds 45% by mass, the vulcanization rate may decrease, the strength and rigidity may decrease, and the loss tangent (tan ⁇ at 60° C.) may increase. Note that the vinyl unit content of the terminal-modified styrene-butadiene rubber can be measured by infrared spectroscopy (Hampton method).
- the concentration of the terminal modified group in the terminal-modified styrene-butadiene rubber is determined in relation to the weight average molecular weight (Mw) of the terminal-modified styrene-butadiene rubber.
- Mw weight average molecular weight of the terminal-modified styrene-butadiene rubber.
- the weight average molecular weight of the terminal-modified styrene-butadiene rubber is preferably 600,000 to 1,000,000, more preferably 650,000 to 850,000.
- the weight average molecular weight of the terminal-modified styrene-butadiene rubber is less than 600,000, the concentration of modifying groups at the end of the terminal-modified styrene-butadiene rubber becomes high, and in terms of the characteristics of the rubber composition, the dispersibility of silica is improved, but the polymer Since its own molecular weight is low, there is a possibility that strength and rigidity will not be developed, and the range of improvement in high-temperature viscoelastic properties will be small. Furthermore, the abrasion resistance of the rubber composition may be reduced.
- the weight average molecular weight of the terminal-modified styrene-butadiene rubber exceeds 1 million, the concentration of the modifying group at the end of the terminal-modified styrene-butadiene rubber becomes low, resulting in insufficient affinity with silica, and there is a possibility that dispersibility may deteriorate.
- the weight average molecular weight (Mw) of the terminal-modified styrene-butadiene rubber can be measured by gel permeation chromatography (GPC) in terms of standard polystyrene.
- the moldability of the rubber composition can be improved.
- the amount of oil extended is 23% by mass or more, preferably 23 to 45% by mass, and more preferably 25 to 40% by mass based on 100% by mass of the terminally modified styrene-butadiene rubber.
- the content of the terminal-modified styrene-butadiene rubber is 30 to 60% by weight, preferably 35 to 55% by weight, and more preferably 40 to 50% by weight based on 100% by weight of the diene rubber. If the content of the terminal-modified styrene-butadiene rubber is less than 30% by mass in the diene rubber, the affinity with silica decreases, making it impossible to improve the dispersibility of silica. Furthermore, if the content of the terminal-modified styrene-butadiene rubber exceeds 60% by mass in the diene rubber, there is a risk that on-snow performance and abrasion resistance may deteriorate.
- the rubber composition for tires may contain other diene rubbers other than the terminal-modified styrene-butadiene rubber as a rubber component within a range that does not impede the object of the present invention.
- diene rubbers include natural rubber, isoprene rubber, butadiene rubber, non-end-modified styrene-butadiene rubber, butyl rubber, and halogenated butyl rubber.
- diene rubbers can be used alone or as a blend of a plurality of them.
- the rubber composition for tires preferably contains natural rubber because it can improve wear resistance and wet grip performance while maintaining a high level of on-snow performance.
- the amount of natural rubber blended is preferably 8 to 35% by weight, more preferably 10 to 25% by weight based on 100% by weight of the diene rubber. It is preferable to blend natural rubber in an amount of 8% by mass or more because it improves on-snow performance, wet grip performance, and abrasion resistance. Further, it is preferable to blend natural rubber in an amount of 35% by mass or less, since wet grip properties can be maintained and improved.
- the natural rubber those commonly used in rubber compositions for tires may be used.
- the rubber composition for tires preferably contains butadiene rubber because it can improve wear resistance and on-snow performance.
- the amount of butadiene rubber blended is preferably 15 to 40% by weight, more preferably 25 to 35% by weight based on 100% by weight of the diene rubber. It is preferable to mix 15% by mass or more of butadiene rubber, since it is possible to maintain and improve wear resistance. In addition, it is preferable to mix 40% by mass or less of butadiene rubber, since chipping resistance can be maintained and improved.
- the butadiene rubber those commonly used in rubber compositions for tires may be used.
- the diene rubber has an average glass transition temperature of -70°C to -55°C.
- the average glass transition temperature of the diene rubber is preferably -65°C to -55°C, more preferably -60°C to -55°C.
- the average glass transition temperature of the diene rubber can be determined as a weighted average value based on the mass fraction of the glass transition temperature of each diene rubber constituting the rubber composition. Further, the glass transition temperature of each diene rubber can be determined by measuring a thermogram using differential scanning calorimetry (DSC) at a heating rate of 20° C./min, and can be determined as the temperature at the midpoint of the transition range.
- DSC differential scanning calorimetry
- the tire rubber composition preferably has an average vinyl content of 40% by mass or less in the butadiene polymerization component in the diene rubber.
- the butadiene polymerization component in the diene rubber refers to the butadiene polymerization component contained in styrene-styrene-butadiene rubber, the butadiene polymerization component contained in butadiene rubber, and the like.
- the butadiene polymerization component is composed of 1,2-bonds or 1,4-bonds, and the average vinyl content is 1,2-bonds in 100% by mass of the total of 1,2-bonds and 1,4-bonds. mass%.
- the average vinyl content in the butadiene polymerization component in the diene rubber By setting the average vinyl content in the butadiene polymerization component in the diene rubber to 40% by mass or less, wet performance after long-term use can be maintained, which is preferable.
- the average vinyl content is more preferably 10 to 40% by weight, even more preferably 10 to 35% by weight.
- the average vinyl content in the butadiene polymerization component in the diene rubber can be measured by infrared spectroscopy (Hampton method).
- the rubber composition for tires of the present invention contains 70 parts by mass or more of an inorganic filler containing silica and carbon black per 100 parts by mass of diene rubber.
- an inorganic filler containing silica and carbon black per 100 parts by mass of diene rubber.
- the inorganic filler is preferably blended in an amount of 70 to 100 parts by mass, more preferably 70 to 90 parts by mass, per 100 parts by mass of the diene rubber.
- the content of silica in 100% by mass of the inorganic filler is 60% by mass or more, preferably 60 to 90% by mass.
- the content of silica in the inorganic filler is 60% by mass or more, preferably 60 to 90% by mass.
- carbon blacks commonly used in tire rubber compositions can be used, and examples thereof include carbon blacks such as furnace black, acetylene black, thermal black, channel black, and graphite.
- furnace black is preferred, and specific examples thereof include SAF, ISAF, ISAF-HS, ISAF-LS, IISAF-HS, HAF, HAF-HS, HAF-LS, FEF, and the like.
- SAF SAF
- ISAF ISAF-HS
- ISAF-LS ISAF-LS
- IISAF-HS High-HS
- HAF HAF-HS
- HAF-LS HAF-LS
- FEF and the like.
- carbon blacks can be used alone or in combination of two or more.
- surface-treated carbon blacks obtained by chemically modifying these carbon blacks with various acid compounds can also be used.
- silica commonly used in tire rubber compositions, such as wet-process silica, dry-process silica, or surface-treated silica, can be used.
- the particle properties of silica are not particularly limited, it is preferable that the DBP absorption amount determined according to JIS K6217-4 oil absorption method A is 160 to 220 ml/100 g, and the DBP absorption amount determined according to JIS K6217-2. At least 1 of the particle properties such as nitrogen adsorption specific surface area (N 2 SA) determined by It is good to meet the following criteria.
- N 2 SA nitrogen adsorption specific surface area
- the breaking strength may decrease. If the DBP absorption amount exceeds 220 ml/100 g, the viscosity may become too high and the mixing processability may deteriorate. If the N 2 SA of silica is less than 145 m 2 /g, wet grip properties may deteriorate. Furthermore, if the N 2 SA of the silica exceeds 193 m 2 /g, the dispersibility of the silica may deteriorate and the abrasion resistance may deteriorate, and the rubber composition may become hard and the on-snow performance may deteriorate.
- CTAB of silica If the CTAB of silica is less than 140 m 2 /g, wet grip properties may deteriorate. Furthermore, if the CTAB of silica exceeds 184 m 2 /g, the dispersibility of silica may deteriorate and wear resistance may deteriorate.
- Silica can be appropriately selected and used from commercially available silica. Moreover, silica obtained by a normal manufacturing method can be used.
- the dispersibility of silica can be improved by blending silica that satisfies the above-mentioned particle properties with terminally modified styrene-butadiene rubber. Therefore, the terminal-modified styrene-butadiene rubber and the silica having the above-mentioned particle properties can modify the tan ⁇ of the rubber composition together to obtain a further synergistic effect.
- a silane coupling agent with silica, which can improve the dispersibility of silica and further enhance the reinforcing properties with the diene rubber.
- the silane coupling agent is preferably blended in an amount of 3 to 20% by mass, more preferably 5 to 15% by mass, based on the amount of silica blended.
- the blending amount of the silane coupling agent is less than 3% by mass of the silica weight, the effect of improving the dispersibility of silica cannot be sufficiently obtained.
- the amount of the silane coupling agent exceeds 20% by mass, the silane coupling agents will condense with each other, making it impossible to obtain the desired effect.
- the silane coupling agent is not particularly limited, but sulfur-containing silane coupling agents are preferred, such as bis-(3-triethoxysilylpropyl)tetrasulfide and bis(3-triethoxysilylpropyl)disulfide. , 3-trimethoxysilylpropylbenzothiazole tetrasulfide, ⁇ -mercaptopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane and the like.
- the tire rubber composition of the present invention may contain inorganic fillers other than silica and carbon black.
- examples of other inorganic fillers include clay, mica, talc, calcium carbonate, aluminum hydroxide, aluminum oxide, and titanium oxide.
- the content of other inorganic fillers is preferably 30% by mass or less, preferably 0 to 25% by mass based on 100% by mass of inorganic fillers. When the content of other inorganic fillers exceeds 30% by mass, fuel efficiency deteriorates.
- the tensile stress Mi at 300% deformation of the cured product and the tensile stress Ma at 300% deformation after heat-treating the cured product at 50° C. for 1000 hours are as follows: (Ma-Mi)/Mi ⁇ 0.3 satisfy.
- the tensile stress at 300% deformation is the stress at 300% deformation measured using a No. 3 dumbbell test piece at a tensile rate of 500 mm/min and a temperature of 20°C in accordance with JIS K6251. [MPa].
- the total oil component is preferably 25 to 50% by mass, more preferably 30 to 45% by mass based on 100% by mass of the rubber composition. If the total amount of oil components is less than 25% by mass, there is a risk that on-snow performance may not be sufficiently improved. Moreover, if the total amount of oil components exceeds 50% by mass, there is a possibility that the wear resistance cannot be sufficiently improved.
- the total oil component is the total oil component contained in the rubber composition, which consists of the oil extending oil in the diene rubber and oil components such as natural oil, synthetic oil, and plasticizer added during the preparation of the rubber composition. means.
- vulcanization or crosslinking agents Commonly used in tire rubber compositions include vulcanization or crosslinking agents, vulcanization accelerators, anti-aging agents, plasticizers, processing aids, liquid polymers, terpene resins, thermosetting resins, etc.
- Various compounding agents commonly used can be blended. Such compounding agents can be kneaded in a conventional manner to form a rubber composition, which can be used for vulcanization or crosslinking.
- the amounts of these compounding agents can be any conventional and common amounts as long as they do not contradict the purpose of the present invention.
- the rubber composition for tires can be produced by mixing the above-mentioned components using a known rubber kneading machine such as a Banbury mixer, kneader, roll, etc.
- the rubber composition for tires of the present invention can be suitably used for tires, pneumatic tires, especially all-season pneumatic tires for passenger cars. Tires using this rubber composition in their treads can improve the balance between snow performance when driving on snow-covered roads and wet performance and wear resistance when driving on non-snow-covered roads beyond conventional levels. can.
- the average glass transition temperature of the diene rubber is written in the column "Average Tg of rubber °C"
- the average vinyl content in the butadiene polymerization component in the diene rubber is "average vinyl content (mass%) of the butadiene polymerization component”. It was written in the column.
- the obtained 15 types of rubber compositions were vulcanized at 160° C. for 30 minutes using a predetermined mold to produce vulcanized rubber test pieces.
- the initial tensile stress Mi at 300% deformation and the tensile stress Ma at 300% deformation after heat treatment at 50° C. for 1000 hours were evaluated by the following measuring method.
- pneumatic tires of size (225/60R18) using 15 types of rubber compositions for the cap tread were vulcanized and molded. Using each pneumatic tire, abrasion resistance, on-snow performance, and wet grip performance after long-term use were evaluated by the methods shown below.
- the obtained pneumatic tire was assembled on a wheel with a rim size of 18 x 7 JJ, filled with air pressure of 220 kPa, and installed on a domestically produced 2.5 liter class test vehicle, and was tested on the dry road surface of a 5 km circuit of the test course.
- the vehicle ran 10 laps continuously at a speed of 80 km/hour. Thereafter, the state of wear on the tread surface was visually observed, and the standard example was evaluated using a score of 100.
- the obtained results are shown in the "Abrasion Resistance" column of Tables 1 and 2. The larger the evaluation value, the better the wear resistance.
- Performance on snow The obtained pneumatic tire was assembled onto a wheel with a rim size of 18 x 7JJ, mounted on a domestically produced 2.5 liter class test vehicle, and the tire was driven around a 2.6km test course in snowy conditions at an air pressure of 200kPa.
- the vehicle was driven in an actual vehicle, and three expert panelists evaluated the steering stability using a score rating of 100 for the standard example.
- the obtained results are shown in the "Snow performance" column of Tables 1 and 2. The larger the evaluation value, the better the performance on snow (steering stability) on snowy roads.
- the obtained pneumatic tire was assembled onto a wheel with a rim size of 18 x 7JJ, mounted on a test vehicle, and the vehicle was driven for 2000 km.
- the pneumatic tires were assembled onto wheels with a rim size of 18 x 7 JJ, mounted on a domestically produced 2.5 liter class test vehicle, and the actual vehicle was driven around a 2.6 km test course with a wet road surface at an air pressure of 220 kPa.
- the vehicle was run, and the steering stability at that time was evaluated by sensitivity evaluation by three expert panelists, with the standard example being 100.
- the obtained results are shown in the "long-term wet performance" column of Tables 1 and 2. The larger the evaluation value, the better the wet grip performance after long-term use.
- ⁇ Modified SBR1 terminally modified solution polymerized styrene-butadiene rubber modified with hydroxyl groups, TUFDENE E581 manufactured by Asahi Kasei, styrene unit content 36% by mass, vinyl unit content 41% by mass, glass transition temperature (Tg) - 34° C., the content of oil extension oil was 27.27% by mass.
- ⁇ SBR2 Unmodified emulsion polymerized styrene butadiene rubber, Nipol 1502 manufactured by Nippon Zeon, styrene unit content 24% by mass, vinyl unit content 42% by mass, glass transition temperature (Tg) -60°C, non-oil Exhibit.
- ⁇ Modified SBR3 Terminal modified solution polymerized styrene-butadiene rubber modified with hydroxy groups, Nipol NS612 manufactured by Nippon Zeon, styrene unit content 15% by mass, vinyl unit content 31% by mass, glass transition temperature (Tg) -61°C, non-oil-extended product.
- ⁇ SBR4 Unmodified solution polymerized styrene-butadiene rubber, Nipol NS522 manufactured by Nippon Zeon, styrene unit content 38% by mass, vinyl unit content 39% by mass, glass transition temperature (Tg) -23°C, oil extension Oil content is 27.27% by mass.
- ⁇ Modified SBR5 terminally modified solution polymerized styrene-butadiene rubber modified with glycidylamine groups, TUFDENE F3420 manufactured by Asahi Kasei, styrene unit content 36% by mass, vinyl unit content 41% by mass, glass transition temperature (Tg) -27°C, the content of oil extension oil is 16.67% by mass.
- ⁇ BR Butadiene rubber, Nipol BR1220 manufactured by Nippon Zeon, glass transition temperature (Tg) is -106°C ⁇ NR: Natural rubber, PT. SIR20 manufactured by KIRANA SAPTA, glass transition temperature (Tg) is -61°C ⁇ CB1: Carbon black, Seast 7HM manufactured by Tokai Carbon Co., Ltd. ⁇ CB2: Carbon black, OCI Company Ltd. Manufactured by DASH BLACK N134 - Silica 1: ULTRASIL VN3GR manufactured by Evonik. - Silica 2: ULTRASIL 7000GR manufactured by Evonik. ⁇ Coupling agent: Silane coupling agent, Evonik Si69, bis(3-triethoxysilylpropyl) tetrasulfide ⁇ Aroma oil: Showa Shell Sekiyu Extract No. 4 SIR20 manufactured by KIRANA SAPTA, glass transition temperature (Tg) is -61°C ⁇ CB1: Carbon black, Seas
- ⁇ Anti-aging agent 6PPD manufactured by Korea Kumho Petrochemical
- ⁇ Wax OZOACE-0015A manufactured by Nippon Seiseisha
- ⁇ Zinc oxide 3 types of zinc oxide manufactured by Seido Chemical Industry Co., Ltd.
- ⁇ Stearic acid Bead stearic acid manufactured by NOF Corporation
- ⁇ Vulcanization accelerator 1 Noxeler CZ-G manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
- ⁇ Vulcanization accelerator 2 Soccinol DG manufactured by Sumitomo Chemical Co., Ltd.
- ⁇ Sulfur Fine powder sulfur with Kinka seal oil manufactured by Tsurumi Chemical Industry Co., Ltd.
- the tire rubber compositions of Examples 1 to 6 can improve performance on snow and the balance between wet performance and abrasion resistance after long-term use compared to conventional levels.
- the average glass transition temperature of the diene rubber is higher than -50°C, so the abrasion resistance and on-snow performance deteriorate.
- the average glass transition temperature of the diene rubber is lower than -70°C, so the wet grip performance after long-term use deteriorates.
- the weight ratio of silica in the inorganic filler is less than 60% by mass, and the rate of change in tensile stress at 300% deformation after heat treatment is greater than 0.3, so it is difficult to use after long-term use. Wet grip performance deteriorates.
- the weight ratio of silica in the inorganic filler is less than 60% by mass, and the rate of change in tensile stress at 300% deformation after heat treatment is greater than 0.3, so it is difficult to use after long-term use. Wet grip performance deteriorates. Since the rubber composition of Comparative Example 5 contains less than 70 parts by mass of inorganic filler, the abrasion resistance and wet grip performance after long-term use deteriorate. In the rubber composition of Comparative Example 6, since the silica content in the inorganic filler is less than 60% by mass, on-snow performance and wet grip performance after long-term use deteriorate.
- the styrene-butadiene rubber (SBR4) is not terminally modified and the styrene unit content exceeds 37% by mass, resulting in poor on-snow performance and wet grip performance after long-term use.
- the abrasion resistance deteriorates because the oil extending oil in the terminal-modified styrene-butadiene rubber (modified SBR5) is less than 23% by mass.
Abstract
The present invention provides a rubber composition for tires, the rubber composition enabling the achievement of further improved balance among on-snow performance, wet performance and wear resistance. The present invention provides a rubber composition which is obtained by adding 70 parts by mass or more of an inorganic filler that contains silica and carbon black to 100 parts by mass of a diene rubber that contains 30% by mass to 60% by mass of a terminally modified styrene-butadiene rubber and has an average glass transition temperature of -70°C to -55°C, wherein: the silica content in the inorganic filler is 60% by mass or more; and the terminally modified styrene-butadiene rubber contains 23% by mass or more of an extending oil, while having a styrene unit content of 37% by mass or less. This rubber composition is characterized in that the tensile stress Mi of a cured product thereof at 300% deformation and the tensile stress Ma of the cured product at 300% deformation after a heat treatment at 50°C for 1,000 hours satisfy formula (Ma - Mi)/Mi ≤ 0.3.
Description
本発明は、雪上性能およびウェット性能と耐摩耗性とのバランスを一層向上するようにしたタイヤ用ゴム組成物に関する。
The present invention relates to a rubber composition for tires that further improves the balance between on-snow performance, wet performance, and wear resistance.
オールシーズンタイヤには、積雪路面を走行するときの雪上性能と、非積雪路面（湿潤路面）を走行するときのウェット性能に優れることに加え、耐摩耗性に優れることが要求される。タイヤ用ゴム組成物の耐摩耗性を向上するためにカーボンブラックの配合量を多くすると、ウェット性能、とりわけ長期使用後のウェットグリップ性能が低下することがある。
All-season tires are required to have excellent snow performance when driving on snowy roads and wet performance when driving on non-snowy roads (wet roads), as well as excellent wear resistance. If the blending amount of carbon black is increased in order to improve the abrasion resistance of a rubber composition for tires, wet performance, particularly wet grip performance after long-term use, may deteriorate.
一方、ウェット性能を改良するためタイヤ用ゴム組成物にシリカを配合することが行われる。しかしシリカはカーボンブラックに比べ、ジエン系ゴムに配合したとき補強性能が小さいため耐摩耗性が低下するという問題がある。またウェット性能を向上するため、シリカの配合量を増やしたりその粒子径を微細にしたりすると、シリカの分散性が低下し耐摩耗性がさらに低下したり、ゴム組成物の柔軟性が失われ雪上性能が低下するという問題がある。
On the other hand, silica is blended into tire rubber compositions to improve wet performance. However, compared to carbon black, silica has a problem in that its reinforcing performance is lower when blended with diene rubber, resulting in lower wear resistance. In addition, when increasing the amount of silica blended or making the particle size finer to improve wet performance, the dispersibility of silica decreases, further reducing abrasion resistance, and the rubber composition loses its flexibility, making it difficult to handle on snow. There is a problem that performance deteriorates.
特許文献１および２は、末端をポリオルガノシロキサン等で変性した末端変性スチレンブタジエンゴムにシリカを配合したゴム組成物によりシリカの分散性を改良することを提案している。しかし、需要者が雪上性能、ウェット性能および耐摩耗性の向上に期待する要求レベルはより高くこれらの特性を一層改善すること、とりわけ長期使用後のウェットグリップ性能を維持することが求められている。
Patent Documents 1 and 2 propose improving the dispersibility of silica by using a rubber composition in which silica is blended with terminal-modified styrene-butadiene rubber whose terminals are modified with polyorganosiloxane or the like. However, the level of demand that users expect for improvements in on-snow performance, wet performance, and abrasion resistance is higher, and there is a need to further improve these characteristics, especially to maintain wet grip performance after long-term use. .
本発明の目的は、雪上性能およびウェット性能と耐摩耗性とのバランスを従来レベル以上に向上し、かつ長期使用後のウェットグリップ性能を維持するようにしたタイヤ用ゴム組成物を提供することにある。
An object of the present invention is to provide a rubber composition for tires that improves the balance between on-snow performance, wet performance, and abrasion resistance beyond conventional levels, and maintains wet grip performance after long-term use. be.
上記目的を達成する本発明のタイヤ用ゴム組成物は、末端変性スチレンブタジエンゴムを３０～６０質量％含み、平均ガラス転移温度が－７０℃～－５５℃であるジエン系ゴム１００質量部に、シリカおよびカーボンブラックを含む無機充填剤を７０質量部以上配合し、前記無機充填剤中シリカが６０質量％以上であって、前記末端変性スチレンブタジエンゴムが油展オイルを２３質量％以上含有し、そのスチレン単位含有量が３７質量％以下であるゴム組成物であって、その硬化物の３００％変形時の引張応力Ｍｉおよび前記硬化物を５０℃、１０００時間加熱処理した後の３００％変形時の引張応力Ｍａが式；（Ｍａ－Ｍｉ）／Ｍｉ ≦ ０．３ を満たすことを特徴とする。
The tire rubber composition of the present invention which achieves the above object contains 30 to 60 mass% of terminally modified styrene-butadiene rubber and 100 parts by mass of a diene rubber having an average glass transition temperature of -70°C to -55°C. 70 parts by mass or more of an inorganic filler containing silica and carbon black is blended, the silica in the inorganic filler is 60 mass% or more, and the terminal-modified styrene-butadiene rubber contains 23 mass% or more of oil extending oil; A rubber composition whose styrene unit content is 37% by mass or less, the tensile stress Mi at 300% deformation of the cured product and the 300% deformation after heat treating the cured product at 50° C. for 1000 hours. It is characterized in that the tensile stress Ma satisfies the formula: (Ma-Mi)/Mi≦0.3.
本発明のタイヤ用ゴム組成物は、雪上性能およびウェット性能と耐摩耗性とのバランスを従来レベル以上に向上すると共に、長期使用後のウェットグリップ性能を維持することができる。
The tire rubber composition of the present invention can improve the balance between on-snow performance, wet performance, and abrasion resistance beyond conventional levels, and can maintain wet grip performance after long-term use.
タイヤ用ゴム組成物は、前記ジエン系ゴム中のブタジエン重合成分における、平均ビニル含量が４０質量％以下であるとよい。また、前記ジエン系ゴム１００質量部に、前記無機充填剤を７０質量部以上９０質量部以下配合するとよく、さらに前記無機充填剤中シリカが６０質量％以上９０質量％以下であるとよい。
The rubber composition for tires preferably has an average vinyl content of 40% by mass or less in the butadiene polymerization component in the diene rubber. Further, it is preferable that the inorganic filler is blended in 70 parts by mass or more and 90 parts by mass or less with 100 parts by mass of the diene rubber, and furthermore, the content of silica in the inorganic filler is preferably 60 mass% or more and 90 mass% or less.
本発明のタイヤ用ゴム組成物において、ゴム成分はジエン系ゴムであり、そのジエン系ゴムは末端変性スチレンブタジエンゴムを必ず含む。末端変性スチレンブタジエンゴムは、分子鎖の片末端または両末端に官能基を有するスチレンブタジエンゴムである。末端変性スチレンブタジエンゴムは、好ましくは溶液重合で製造したスチレンブタジエンゴムの末端に官能基を有する変性ゴムであるとよい。末端変性スチレンブタジエンゴムを配合することによりシリカとの親和性を高くし分散性を改善するため、シリカの作用効果を一層高くすると共に、耐摩耗性を改良する。
In the rubber composition for tires of the present invention, the rubber component is a diene rubber, and the diene rubber necessarily contains terminally modified styrene-butadiene rubber. Terminal-modified styrene-butadiene rubber is styrene-butadiene rubber that has a functional group at one or both ends of its molecular chain. The terminal-modified styrene-butadiene rubber is preferably a modified rubber having a functional group at the terminal of styrene-butadiene rubber produced by solution polymerization. By blending the terminal-modified styrene-butadiene rubber, the affinity with silica is increased and the dispersibility is improved, which further enhances the effectiveness of silica and improves wear resistance.
また末端変性スチレンブタジエンゴムが有する官能基は、シリカ表面のシラノール基と反応する化合物に由来する官能基であるとよい。このシラノール基と反応する化合物は、特に制限されるものではないが、例えばポリオルガノシロキサン化合物、エポキシ化合物、ヒドロカルビルオキシ珪素化合物、スズ化合物、ケイ素化合物、シラン化合物、アミド化合物および／またはイミド化合物、イソシアネートおよび／またはイソチオシアネート化合物、ケトン化合物、エステル化合物、ビニル化合物、オキシラン化合物、チイラン化合物、オキセタン化合物、ポリスルフィド化合物、ポリシロキサン化合物、ポリエーテル化合物、ポリエン化合物、ハロゲン化合物、フラーレン類などを有する化合物を挙げることができる。なかでもポリオルガノシロキサン化合物、エポキシ化合物、ヒドロカルビルオキシ珪素化合物、が好ましい。
Furthermore, the functional group possessed by the terminal-modified styrene-butadiene rubber is preferably a functional group derived from a compound that reacts with the silanol group on the surface of the silica. Compounds that react with this silanol group are not particularly limited, but include, for example, polyorganosiloxane compounds, epoxy compounds, hydrocarbyloxysilicon compounds, tin compounds, silicon compounds, silane compounds, amide compounds and/or imide compounds, and isocyanates. and/or compounds containing isothiocyanate compounds, ketone compounds, ester compounds, vinyl compounds, oxirane compounds, thiirane compounds, oxetane compounds, polysulfide compounds, polysiloxane compounds, polyether compounds, polyene compounds, halogen compounds, fullerenes, etc. be able to. Among these, polyorganosiloxane compounds, epoxy compounds, and hydrocarbyloxysilicon compounds are preferred.
末端変性スチレンブタジエンゴムは、スチレン単位含有量が３７質量％以下、好ましくは２０～３７質量％、より好ましくは２７～３７質量％である。末端変性スチレンブタジエンゴムのスチレン単位含有量を３７質量％以下にすることにより、タイヤにしたときの雪上性能およびウェット性能をより高くし、特に長期使用後のウェットグリップ性能を維持することができる。本明細書において、末端変性スチレンブタジエンゴムのスチレン単位含有量は赤外分光分析（ハンプトン法）により測定することができる。
The terminally modified styrene-butadiene rubber has a styrene unit content of 37% by mass or less, preferably 20 to 37% by mass, more preferably 27 to 37% by mass. By controlling the styrene unit content of the terminal-modified styrene-butadiene rubber to 37% by mass or less, it is possible to improve the on-snow performance and wet performance when used as a tire, and particularly to maintain wet grip performance after long-term use. In this specification, the styrene unit content of the terminal-modified styrene-butadiene rubber can be measured by infrared spectroscopy (Hampton method).
本発明では、末端変性スチレンブタジエンゴムのビニル単位含有量は好ましくは２０～４５質量％、より好ましくは３５～４５質量％にするとよい。末端変性スチレンブタジエンゴムのビニル単位含有量を２０～４５質量％にすることにより、末端変性スチレンブタジエンゴムのガラス転移温度（Ｔｇ）を適正化することができ好ましい。また、他のジエン系ゴムに対して形成された末端変性スチレンブタジエンゴムの微細な相分離形態を安定化することができる。末端変性スチレンブタジエンゴムのビニル単位含有量が２０質量％未満であると、末端変性スチレンブタジエンゴムのＴｇが低くなり、ウェットグリップ性能が低下する虞がある。また末端変性スチレンブタジエンゴムのビニル単位含有量が４５質量％を超えると加硫速度が低下したり、強度や剛性が低下したり、損失正接（６０℃のｔａｎδ）が大きくなる可能性がある。なお末端変性スチレンブタジエンゴムのビニル単位含有量は赤外分光分析（ハンプトン法）により測定することができる。
In the present invention, the vinyl unit content of the terminal-modified styrene-butadiene rubber is preferably 20 to 45% by mass, more preferably 35 to 45% by mass. By controlling the vinyl unit content of the terminal-modified styrene-butadiene rubber to 20 to 45% by mass, it is possible to optimize the glass transition temperature (Tg) of the terminal-modified styrene-butadiene rubber. Further, it is possible to stabilize the fine phase separation form of terminally modified styrene-butadiene rubber formed with respect to other diene rubbers. If the vinyl unit content of the terminal-modified styrene-butadiene rubber is less than 20% by mass, the Tg of the terminal-modified styrene-butadiene rubber may become low, and wet grip performance may deteriorate. Furthermore, if the vinyl unit content of the terminal-modified styrene-butadiene rubber exceeds 45% by mass, the vulcanization rate may decrease, the strength and rigidity may decrease, and the loss tangent (tan δ at 60° C.) may increase. Note that the vinyl unit content of the terminal-modified styrene-butadiene rubber can be measured by infrared spectroscopy (Hampton method).
本発明では、末端変性スチレンブタジエンゴムにおける末端変性基の濃度は、末端変性スチレンブタジエンゴムの重量平均分子量（Ｍｗ）との関係で決められる。末端変性スチレンブタジエンゴムの重量平均分子量は好ましくは６０万～１００万、より好ましくは６５～８５万であるとよい。末端変性スチレンブタジエンゴムの重量平均分子量が６０万未満であると、末端変性スチレンブタジエンゴム末端の変性基濃度が高くなり、ゴム組成物の特性において、シリカの分散性は良化するが、重合体自身の分子量が低いために、強度、剛性が発現しない可能性があり、高温の粘弾性特性の改良幅も小さくなってしまう。またゴム組成物の耐摩耗性が低下することがある。また末端変性スチレンブタジエンゴムの重量平均分子量が１００万を超えると、末端変性スチレンブタジエンゴム末端の変性基濃度が低くなりシリカとの親和性が不足し、分散性が悪化する虞がある。なお末端変性スチレンブタジエンゴムの重量平均分子量（Ｍｗ）は、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）により標準ポリスチレン換算により測定することができる。
In the present invention, the concentration of the terminal modified group in the terminal-modified styrene-butadiene rubber is determined in relation to the weight average molecular weight (Mw) of the terminal-modified styrene-butadiene rubber. The weight average molecular weight of the terminal-modified styrene-butadiene rubber is preferably 600,000 to 1,000,000, more preferably 650,000 to 850,000. If the weight average molecular weight of the terminal-modified styrene-butadiene rubber is less than 600,000, the concentration of modifying groups at the end of the terminal-modified styrene-butadiene rubber becomes high, and in terms of the characteristics of the rubber composition, the dispersibility of silica is improved, but the polymer Since its own molecular weight is low, there is a possibility that strength and rigidity will not be developed, and the range of improvement in high-temperature viscoelastic properties will be small. Furthermore, the abrasion resistance of the rubber composition may be reduced. Furthermore, if the weight average molecular weight of the terminal-modified styrene-butadiene rubber exceeds 1 million, the concentration of the modifying group at the end of the terminal-modified styrene-butadiene rubber becomes low, resulting in insufficient affinity with silica, and there is a possibility that dispersibility may deteriorate. The weight average molecular weight (Mw) of the terminal-modified styrene-butadiene rubber can be measured by gel permeation chromatography (GPC) in terms of standard polystyrene.
末端変性スチレンブタジエンゴムは、オイル成分を添加すること（油展）によりゴム組成物の成形加工性を良好にすることができる。油展量は、末端変性スチレンブタジエンゴム１００質量％中、２３質量％以上、好ましくは２３～４５質量％、より好ましくは２５～４０質量％である。末端変性スチレンブタジエンゴムの油展量を２３質量％以上にすることにより、ゴム組成物にオイル、軟化剤、粘着性付与剤等を配合するときの組成設計の自由度が得られる。
By adding an oil component to the terminal-modified styrene-butadiene rubber (oil extension), the moldability of the rubber composition can be improved. The amount of oil extended is 23% by mass or more, preferably 23 to 45% by mass, and more preferably 25 to 40% by mass based on 100% by mass of the terminally modified styrene-butadiene rubber. By setting the oil extension amount of the terminal-modified styrene-butadiene rubber to 23% by mass or more, a degree of freedom in compositional design can be obtained when adding oil, softener, tackifier, etc. to the rubber composition.
末端変性スチレンブタジエンゴムの含有量は、ジエン系ゴム１００質量％中、３０～６０質量％、好ましくは３５～５５質量％、より好ましくは４０～５０質量％である。末端変性スチレンブタジエンゴムの含有量がジエン系ゴム中の３０質量％未満であると、シリカとの親和性が低下するのでシリカの分散性を良好にすることができない。また末端変性スチレンブタジエンゴムの含有量がジエン系ゴム中の６０質量％を超えると、雪上性能および耐摩耗性が低下する虞がある。
The content of the terminal-modified styrene-butadiene rubber is 30 to 60% by weight, preferably 35 to 55% by weight, and more preferably 40 to 50% by weight based on 100% by weight of the diene rubber. If the content of the terminal-modified styrene-butadiene rubber is less than 30% by mass in the diene rubber, the affinity with silica decreases, making it impossible to improve the dispersibility of silica. Furthermore, if the content of the terminal-modified styrene-butadiene rubber exceeds 60% by mass in the diene rubber, there is a risk that on-snow performance and abrasion resistance may deteriorate.
タイヤ用ゴム組成物は、ゴム成分として、末端変性スチレンブタジエンゴム以外の他のジエン系ゴムを、本発明の目的を阻害しない範囲で配合することができる。他のジエン系ゴムとして、例えば、天然ゴム、イソプレンゴム、ブタジエンゴム、末端変性していないスチレンブタジエンゴム、ブチルゴム、ハロゲン化ブチルゴム等を例示することができる。このようなジエン系ゴムは、単独又は複数のブレンドとして使用することができる。
The rubber composition for tires may contain other diene rubbers other than the terminal-modified styrene-butadiene rubber as a rubber component within a range that does not impede the object of the present invention. Examples of other diene rubbers include natural rubber, isoprene rubber, butadiene rubber, non-end-modified styrene-butadiene rubber, butyl rubber, and halogenated butyl rubber. Such diene rubbers can be used alone or as a blend of a plurality of them.
タイヤ用ゴム組成物は、天然ゴムを含有することにより雪上性能を高いレベルで維持しながら耐摩耗性およびウェットグリップ性能を改良することができ好ましい。天然ゴムの配合量は、ジエン系ゴム１００質量％中、好ましくは８～３５質量％、より好ましくは１０～２５質量％にするとよい。天然ゴムを８質量％以上配合すると、雪上性能、ウェットグリップ性能および耐摩耗性を改良することができ好ましい。また天然ゴムを３５質量％以下配合すると、ウェットグリップ性を維持、向上することができ好ましい。天然ゴムとしては、タイヤ用ゴム組成物に通常用いられるものを使用するとよい。
The rubber composition for tires preferably contains natural rubber because it can improve wear resistance and wet grip performance while maintaining a high level of on-snow performance. The amount of natural rubber blended is preferably 8 to 35% by weight, more preferably 10 to 25% by weight based on 100% by weight of the diene rubber. It is preferable to blend natural rubber in an amount of 8% by mass or more because it improves on-snow performance, wet grip performance, and abrasion resistance. Further, it is preferable to blend natural rubber in an amount of 35% by mass or less, since wet grip properties can be maintained and improved. As the natural rubber, those commonly used in rubber compositions for tires may be used.
タイヤ用ゴム組成物は、ブタジエンゴムを含有することにより、耐摩耗性および雪上性能を改良することができ好ましい。ブタジエンゴムの配合量はジエン系ゴム１００質量％中、好ましくは１５～４０質量％、より好ましくは２５～３５質量％にするとよい。ブタジエンゴムを１５質量％以上配合すると、耐摩耗性を維持、向上することができ好ましい。またブタジエンゴムを４０質量％以下配合すると、耐チッピング性を維持、向上することができ好ましい。ブタジエンゴムとしては、タイヤ用ゴム組成物に通常用いられるものを使用するとよい。
The rubber composition for tires preferably contains butadiene rubber because it can improve wear resistance and on-snow performance. The amount of butadiene rubber blended is preferably 15 to 40% by weight, more preferably 25 to 35% by weight based on 100% by weight of the diene rubber. It is preferable to mix 15% by mass or more of butadiene rubber, since it is possible to maintain and improve wear resistance. In addition, it is preferable to mix 40% by mass or less of butadiene rubber, since chipping resistance can be maintained and improved. As the butadiene rubber, those commonly used in rubber compositions for tires may be used.
タイヤ用ゴム組成物は、ジエン系ゴムの平均ガラス転移温度が－７０℃～－５５℃である。ジエン系ゴムのタイヤ用ゴム組成物平均ガラス転移温度を－７０℃～－５５℃にすることにより、雪上性能およびウェット性能と耐摩耗性とのバランスを優れたものにすることができる。ジエン系ゴムの平均ガラス転移温度は、好ましくは－６５℃～－５５℃、より好ましくは－６０℃～－５５℃であるとよい。本明細書において、ジエン系ゴムの平均ガラス転移温度は、ゴム組成物を構成する各ジエン系ゴムのガラス転移温度の質量分率に基づく加重平均値として求めることができる。また、各ジエン系ゴムのガラス転移温度は、示差走査熱量分析（ＤＳＣ）により２０℃／分の昇温速度条件によりサーモグラムを測定し、転移域の中点の温度とすることができる。
In the tire rubber composition, the diene rubber has an average glass transition temperature of -70°C to -55°C. By setting the average glass transition temperature of the diene rubber tire rubber composition to -70°C to -55°C, it is possible to achieve an excellent balance between on-snow performance, wet performance, and abrasion resistance. The average glass transition temperature of the diene rubber is preferably -65°C to -55°C, more preferably -60°C to -55°C. In this specification, the average glass transition temperature of the diene rubber can be determined as a weighted average value based on the mass fraction of the glass transition temperature of each diene rubber constituting the rubber composition. Further, the glass transition temperature of each diene rubber can be determined by measuring a thermogram using differential scanning calorimetry (DSC) at a heating rate of 20° C./min, and can be determined as the temperature at the midpoint of the transition range.
タイヤ用ゴム組成物は、ジエン系ゴム中のブタジエン重合成分における、平均ビニル含量が４０質量％以下であるとよい。ジエン系ゴム中のブタジエン重合成分とは、スチレンスチレンブタジエンゴムに含まれるブタジエン重合成分、ブタジエンゴムに含まれるブタジエン重合成分、等をいう。ブタジエン重合成分は、１，２－結合または１，４－結合で構成されており、平均ビニル含量は、１，２－結合および１，４－結合の合計１００質量％中の１，２－結合の質量％である。ジエン系ゴム中のブタジエン重合成分における、平均ビニル含量を４０質量％以下にすることにより、長期使用後のウェット性能を保つことができるため好ましい。平均ビニル含量は、より好ましくは１０～４０質量％、さらに好ましくは１０～３５質量％であるとよい。本明細書において、ジエン系ゴム中のブタジエン重合成分における平均ビニル含量は、赤外分光分析（ハンプトン法）により測定することができる。
The tire rubber composition preferably has an average vinyl content of 40% by mass or less in the butadiene polymerization component in the diene rubber. The butadiene polymerization component in the diene rubber refers to the butadiene polymerization component contained in styrene-styrene-butadiene rubber, the butadiene polymerization component contained in butadiene rubber, and the like. The butadiene polymerization component is composed of 1,2-bonds or 1,4-bonds, and the average vinyl content is 1,2-bonds in 100% by mass of the total of 1,2-bonds and 1,4-bonds. mass%. By setting the average vinyl content in the butadiene polymerization component in the diene rubber to 40% by mass or less, wet performance after long-term use can be maintained, which is preferable. The average vinyl content is more preferably 10 to 40% by weight, even more preferably 10 to 35% by weight. In this specification, the average vinyl content in the butadiene polymerization component in the diene rubber can be measured by infrared spectroscopy (Hampton method).
本発明のタイヤ用ゴム組成物は、シリカおよびカーボンブラックを含む無機充填剤をジエン系ゴム１００質量部に対し７０質量部以上配合する。無機充填剤の配合量をこのような範囲にすることにより、ゴム組成物のウェットグリップ性および耐摩耗性をより高いレベルでバランスさせることができる。充填剤の配合量が７０質量部未満であると、高いレベルのウェットグリップ性を確保することができない。無機充填剤は、ジエン系ゴム１００質量部に対し、好ましくは７０～１００質量部、より好ましくは７０～９０質量部配合するとよい。
The rubber composition for tires of the present invention contains 70 parts by mass or more of an inorganic filler containing silica and carbon black per 100 parts by mass of diene rubber. By controlling the blending amount of the inorganic filler within this range, the wet grip properties and abrasion resistance of the rubber composition can be balanced at a higher level. If the blending amount of the filler is less than 70 parts by mass, a high level of wet grip cannot be ensured. The inorganic filler is preferably blended in an amount of 70 to 100 parts by mass, more preferably 70 to 90 parts by mass, per 100 parts by mass of the diene rubber.
また無機充填剤１００質量％中のシリカの含有量は６０質量％以上、好ましくは６０～９０質量％にする。無機充填剤中のシリカの含有量をこのような範囲にすることにより、ゴム組成物のウェットグリップ性および耐摩耗性を両立することが可能になる。また、シリカとの親和性が高い末端変性スチレンブタジエンゴムを配合することにより、シリカの分散性を改善するため、シリカ配合の効果をより高くすることができる。
The content of silica in 100% by mass of the inorganic filler is 60% by mass or more, preferably 60 to 90% by mass. By setting the content of silica in the inorganic filler within this range, it becomes possible to achieve both wet grip properties and abrasion resistance of the rubber composition. Further, by blending terminal-modified styrene-butadiene rubber that has high affinity with silica, the dispersibility of silica is improved, so the effect of silica blending can be further enhanced.
カーボンブラックとして、タイヤ用ゴム組成物に通常用いられるカーボンブラックを使用することができ、例えばファーネスブラック、アセチレンブラック、サーマルブラック、チャンネルブラック、グラファイトなどのカーボンブラックが挙げられる。これらの中でも、ファーネスブラックが好ましく、その具体例として、ＳＡＦ、ＩＳＡＦ、ＩＳＡＦ－ＨＳ、ＩＳＡＦ－ＬＳ、ＩＩＳＡＦ－ＨＳ、ＨＡＦ、ＨＡＦ－ＨＳ、ＨＡＦ－ＬＳ、ＦＥＦなどが挙げられる。これらのカーボンブラックは、それぞれ単独で、あるいは２種以上を組み合わせて用いることができる。また、これらのカーボンブラックを種々の酸化合物等で化学修飾を施した表面処理カーボンブラックも用いることができる。
As the carbon black, carbon blacks commonly used in tire rubber compositions can be used, and examples thereof include carbon blacks such as furnace black, acetylene black, thermal black, channel black, and graphite. Among these, furnace black is preferred, and specific examples thereof include SAF, ISAF, ISAF-HS, ISAF-LS, IISAF-HS, HAF, HAF-HS, HAF-LS, FEF, and the like. These carbon blacks can be used alone or in combination of two or more. Furthermore, surface-treated carbon blacks obtained by chemically modifying these carbon blacks with various acid compounds can also be used.
シリカとしては、タイヤ用ゴム組成物に通常使用されるシリカ、例えば湿式法シリカ、乾式法シリカあるいは表面処理シリカなどを使用することができる。またシリカの粒子性状は、特に制限されるものではないが、好ましくは、ＪＩＳ Ｋ６２１７－４吸油量Ａ法に準拠して求められるＤＢＰ吸収量が１６０～２２０ｍｌ／１００ｇ、ＪＩＳ Ｋ６２１７－２に準拠して求められる窒素吸着比表面積（Ｎ2ＳＡ）が１４５～１９３ｍ2／ｇ、ＪＩＳ Ｋ６２１７－３に準拠して求めるＣＴＡＢ比表面積（ＣＴＡＢ）が１４０～１８４ｍ2／ｇ、等の粒子性状の少なくとも１つを満たすとよい。
As the silica, silica commonly used in tire rubber compositions, such as wet-process silica, dry-process silica, or surface-treated silica, can be used. Although the particle properties of silica are not particularly limited, it is preferable that the DBP absorption amount determined according to JIS K6217-4 oil absorption method A is 160 to 220 ml/100 g, and the DBP absorption amount determined according to JIS K6217-2. At least 1 of the particle properties such as nitrogen adsorption specific surface area (N 2 SA) determined by It is good to meet the following criteria.
シリカのＤＢＰ吸収量が１６０ｍｌ／１００ｇ未満であると、破断強度が低下することがある。ＤＢＰ吸収量が２２０ｍｌ／１００ｇを超えると、粘度が高くなり過ぎて混合加工性が悪化することがある。シリカのＮ2ＳＡが１４５ｍ2／ｇ未満であるとウェットグリップ性が悪化することがある。またシリカのＮ2ＳＡが１９３ｍ2／ｇを超えると、シリカの分散性が悪化し、耐摩耗性が悪化することがあり、またゴム組成物が硬くなり雪上性能が低下することがある。シリカのＣＴＡＢが１４０ｍ2／ｇ未満であるとウェットグリップ性が悪化することがある。またシリカのＣＴＡＢが１８４ｍ2／ｇを超えると、シリカの分散性が悪化し、耐摩耗性が悪化することがある。シリカは、市販されているものの中から適宜選択して使用することができる。また通常の製造方法により得られたシリカを使用することができる。
If the DBP absorption amount of silica is less than 160 ml/100 g, the breaking strength may decrease. If the DBP absorption amount exceeds 220 ml/100 g, the viscosity may become too high and the mixing processability may deteriorate. If the N 2 SA of silica is less than 145 m 2 /g, wet grip properties may deteriorate. Furthermore, if the N 2 SA of the silica exceeds 193 m 2 /g, the dispersibility of the silica may deteriorate and the abrasion resistance may deteriorate, and the rubber composition may become hard and the on-snow performance may deteriorate. If the CTAB of silica is less than 140 m 2 /g, wet grip properties may deteriorate. Furthermore, if the CTAB of silica exceeds 184 m 2 /g, the dispersibility of silica may deteriorate and wear resistance may deteriorate. Silica can be appropriately selected and used from commercially available silica. Moreover, silica obtained by a normal manufacturing method can be used.
上述した粒子性状を満たすシリカは、末端変性スチレンブタジエンゴムと共に配合することにより、シリカの分散性を改良することができる。このため、末端変性スチレンブタジエンゴムおよび上記の粒子性状を有するシリカがゴム組成物のｔａｎδを共に改質し、さらなる相乗的効果を得ることができる。
The dispersibility of silica can be improved by blending silica that satisfies the above-mentioned particle properties with terminally modified styrene-butadiene rubber. Therefore, the terminal-modified styrene-butadiene rubber and the silica having the above-mentioned particle properties can modify the tan δ of the rubber composition together to obtain a further synergistic effect.
本発明のゴム組成物において、シリカと共にシランカップリング剤を配合することが好ましく、シリカの分散性を向上しジエン系ゴムとの補強性をより高くすることができる。シランカップリング剤は、シリカ配合量に対して好ましくは３～２０質量％、より好ましくは５～１５質量％配合するとよい。シランカップリング剤の配合量がシリカ重量の３質量％未満の場合、シリカの分散性を向上する効果が十分に得られない。また、シランカップリング剤の配合量が２０質量％を超えると、シランカップリング剤同士が縮合してしまい、所望の効果を得ることができなくなる。
In the rubber composition of the present invention, it is preferable to blend a silane coupling agent with silica, which can improve the dispersibility of silica and further enhance the reinforcing properties with the diene rubber. The silane coupling agent is preferably blended in an amount of 3 to 20% by mass, more preferably 5 to 15% by mass, based on the amount of silica blended. When the blending amount of the silane coupling agent is less than 3% by mass of the silica weight, the effect of improving the dispersibility of silica cannot be sufficiently obtained. Furthermore, if the amount of the silane coupling agent exceeds 20% by mass, the silane coupling agents will condense with each other, making it impossible to obtain the desired effect.
シランカップリング剤としては、特に制限されるものではないが、硫黄含有シランカップリング剤が好ましく、例えばビス－（３－トリエトキシシリルプロピル）テトラサルファイド、ビス（３－トリエトキシシリルプロピル）ジサルファイド、３－トリメトキシシリルプロピルベンゾチアゾールテトラサルファイド、γ－メルカプトプロピルトリエトキシシラン、３－オクタノイルチオプロピルトリエトキシシラン等を例示することができる。
The silane coupling agent is not particularly limited, but sulfur-containing silane coupling agents are preferred, such as bis-(3-triethoxysilylpropyl)tetrasulfide and bis(3-triethoxysilylpropyl)disulfide. , 3-trimethoxysilylpropylbenzothiazole tetrasulfide, γ-mercaptopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane and the like.
本発明のタイヤ用ゴム組成物は、シリカ、カーボンブラック以外のその他の無機充填剤を配合することができる。その他の無機充填剤としては、例えば、クレー、マイカ、タルク、炭酸カルシウム、水酸化アルミニウム、酸化アルミニウム、酸化チタン等が例示される。その他の無機充填剤の含有量は、無機充填剤１００質量％中３０質量％以下、好ましくは０～２５質量％にするとよい。その他の無機充填剤の含有量が３０質量％を超えると低燃費性能が悪化する。
The tire rubber composition of the present invention may contain inorganic fillers other than silica and carbon black. Examples of other inorganic fillers include clay, mica, talc, calcium carbonate, aluminum hydroxide, aluminum oxide, and titanium oxide. The content of other inorganic fillers is preferably 30% by mass or less, preferably 0 to 25% by mass based on 100% by mass of inorganic fillers. When the content of other inorganic fillers exceeds 30% by mass, fuel efficiency deteriorates.
タイヤ用ゴム組成物は、その硬化物の３００％変形時の引張応力Ｍｉおよび前記硬化物を５０℃、１０００時間加熱処理した後の３００％変形時の引張応力Ｍａが以下の式；
（Ｍａ－Ｍｉ）／Ｍｉ ≦ ０．３
を満たす。上記式の関係を満たすことにより、熱老化後の劣化が抑制され、タイヤにしたときのウェットグリップ性能が、長期間使用した後でも優れていることの指標になる。本明細書において、３００％変形時の引張応力は、ＪＩＳ Ｋ６２５１に準拠して３号型ダンベル試験片を用い、引張速度５００ｍｍ／分、温度２０℃の条件で測定された３００％変形時の応力［ＭＰａ］とする。 In the tire rubber composition, the tensile stress Mi at 300% deformation of the cured product and the tensile stress Ma at 300% deformation after heat-treating the cured product at 50° C. for 1000 hours are as follows:
(Ma-Mi)/Mi ≦ 0.3
satisfy. By satisfying the relationship of the above formula, deterioration after heat aging is suppressed, and the wet grip performance of the tire becomes an indicator that it is excellent even after long-term use. In this specification, the tensile stress at 300% deformation is the stress at 300% deformation measured using a No. 3 dumbbell test piece at a tensile rate of 500 mm/min and a temperature of 20°C in accordance with JIS K6251. [MPa].
（Ｍａ－Ｍｉ）／Ｍｉ ≦ ０．３
を満たす。上記式の関係を満たすことにより、熱老化後の劣化が抑制され、タイヤにしたときのウェットグリップ性能が、長期間使用した後でも優れていることの指標になる。本明細書において、３００％変形時の引張応力は、ＪＩＳ Ｋ６２５１に準拠して３号型ダンベル試験片を用い、引張速度５００ｍｍ／分、温度２０℃の条件で測定された３００％変形時の応力［ＭＰａ］とする。 In the tire rubber composition, the tensile stress Mi at 300% deformation of the cured product and the tensile stress Ma at 300% deformation after heat-treating the cured product at 50° C. for 1000 hours are as follows:
(Ma-Mi)/Mi ≦ 0.3
satisfy. By satisfying the relationship of the above formula, deterioration after heat aging is suppressed, and the wet grip performance of the tire becomes an indicator that it is excellent even after long-term use. In this specification, the tensile stress at 300% deformation is the stress at 300% deformation measured using a No. 3 dumbbell test piece at a tensile rate of 500 mm/min and a temperature of 20°C in accordance with JIS K6251. [MPa].
タイヤ用ゴム組成物は、オイル成分の合計が、ゴム組成物１００質量％中、好ましくは２５～５０質量％、より好ましくは３０～４５質量％であるとよい。オイル成分の合計が２５質量％未満であると、雪上性能を十分に改良することができない虞がある。またオイル成分の合計が５０質量％を超えると、耐摩耗性を十分に改良することができない虞がある。なお、オイル成分の合計とは、ジエン系ゴム中の油展オイル、およびゴム組成物の調製時に添加する天然オイル、合成オイル、可塑剤などのオイル成分からなるゴム組成物が含むオイル成分の合計をいう。
In the rubber composition for tires, the total oil component is preferably 25 to 50% by mass, more preferably 30 to 45% by mass based on 100% by mass of the rubber composition. If the total amount of oil components is less than 25% by mass, there is a risk that on-snow performance may not be sufficiently improved. Moreover, if the total amount of oil components exceeds 50% by mass, there is a possibility that the wear resistance cannot be sufficiently improved. Note that the total oil component is the total oil component contained in the rubber composition, which consists of the oil extending oil in the diene rubber and oil components such as natural oil, synthetic oil, and plasticizer added during the preparation of the rubber composition. means.
タイヤ用ゴム組成物には、加硫又は架橋剤、加硫促進剤、老化防止剤、可塑剤、加工助剤、液状ポリマー、テルペン系樹脂、熱硬化性樹脂などのタイヤ用ゴム組成物に一般的に使用される各種配合剤を配合することができる。このような配合剤は一般的な方法で混練してゴム組成物とし、加硫又は架橋するのに使用することができる。これらの配合剤の配合量は本発明の目的に反しない限り、従来の一般的な配合量とすることができる。タイヤ用ゴム組成物は、公知のゴム用混練機械、例えば、バンバリーミキサー、ニーダー、ロール等を使用して、上記各成分を混合することによって製造することができる。
Commonly used in tire rubber compositions include vulcanization or crosslinking agents, vulcanization accelerators, anti-aging agents, plasticizers, processing aids, liquid polymers, terpene resins, thermosetting resins, etc. Various compounding agents commonly used can be blended. Such compounding agents can be kneaded in a conventional manner to form a rubber composition, which can be used for vulcanization or crosslinking. The amounts of these compounding agents can be any conventional and common amounts as long as they do not contradict the purpose of the present invention. The rubber composition for tires can be produced by mixing the above-mentioned components using a known rubber kneading machine such as a Banbury mixer, kneader, roll, etc.
本発明のタイヤ用ゴム組成物は、タイヤ、空気入りタイヤ、特に乗用車向けのオールシーズン用空気入りタイヤに好適に使用することができる。このゴム組成物をトレッド部に使用したタイヤは、積雪路面を走行するときの雪上性能と、非積雪路面を走行するときのウェット性能や耐摩耗性とのバランスを従来レベル以上に向上することができる。
The rubber composition for tires of the present invention can be suitably used for tires, pneumatic tires, especially all-season pneumatic tires for passenger cars. Tires using this rubber composition in their treads can improve the balance between snow performance when driving on snow-covered roads and wet performance and wear resistance when driving on non-snow-covered roads beyond conventional levels. can.
以下、実施例によって本発明を更に説明するが、本発明の範囲はこれらの実施例に限定されるものではない。
表３に示す配合剤を共通処方とし、表１～２に示す配合からなる１５種類のタイヤ用ゴム組成物（標準例、実施例１～６、比較例１～８）を調製するに当たり、それぞれ硫黄および加硫促進剤を除く成分を秤量し、１.８Ｌの密閉型ミキサーで５分間混練した後、そのマスターバッチを放出し室温冷却した。このマスターバッチを１.８Ｌの密閉型ミキサーに供し、硫黄および加硫促進剤を加え、混合しタイヤ用ゴム組成物を得た。なお、表１，２において、変性ＳＢＲ１，ＳＢＲ４および変性ＳＢＲ５は油展品であるため、正味のゴム量を括弧内に併記した。また、表３の共通処方成分の配合量は、表１，２に示すジエン系ゴム１００質量部に対する質量部として記載した。また、シリカおよびカーボンブラックの合計量を表１，２の「ＣＢ＋シリカ（質量部）」の欄に記載し、シリカおよびカーボンブラックの合計に対するシリカの質量比を「シリカ質量比（質量％）」の欄に記載した。さらに、ジエン系ゴムの平均ガラス転移温度を「ゴムの平均Ｔｇ ℃」の欄に記載し、ジエン系ゴム中のブタジエン重合成分における平均ビニル含量を「ブタジエン重合成分の平均ビニル含量（質量％）」の欄に記載した。 EXAMPLES Hereinafter, the present invention will be further explained with reference to Examples, but the scope of the present invention is not limited to these Examples.
In preparing 15 types of tire rubber compositions (standard example, Examples 1 to 6, Comparative Examples 1 to 8) having the formulations shown in Tables 1 and 2 using the compounding agents shown in Table 3 as a common formulation, each The ingredients except sulfur and vulcanization accelerator were weighed and kneaded for 5 minutes in a 1.8 L internal mixer, and then the masterbatch was discharged and cooled to room temperature. This masterbatch was placed in a 1.8L closed mixer, and sulfur and a vulcanization accelerator were added and mixed to obtain a tire rubber composition. In Tables 1 and 2, since modified SBR1, SBR4 and modified SBR5 are oil-extended products, the net rubber amount is also written in parentheses. Further, the blending amounts of the common prescription components in Table 3 are expressed as parts by mass based on 100 parts by mass of the diene rubber shown in Tables 1 and 2. In addition, the total amount of silica and carbon black is recorded in the "CB + Silica (parts by mass)" column of Tables 1 and 2, and the mass ratio of silica to the total of silica and carbon black is "Silica mass ratio (mass %)". It was written in the column. Furthermore, the average glass transition temperature of the diene rubber is written in the column "Average Tg of rubber ℃", and the average vinyl content in the butadiene polymerization component in the diene rubber is "average vinyl content (mass%) of the butadiene polymerization component". It was written in the column.
表３に示す配合剤を共通処方とし、表１～２に示す配合からなる１５種類のタイヤ用ゴム組成物（標準例、実施例１～６、比較例１～８）を調製するに当たり、それぞれ硫黄および加硫促進剤を除く成分を秤量し、１.８Ｌの密閉型ミキサーで５分間混練した後、そのマスターバッチを放出し室温冷却した。このマスターバッチを１.８Ｌの密閉型ミキサーに供し、硫黄および加硫促進剤を加え、混合しタイヤ用ゴム組成物を得た。なお、表１，２において、変性ＳＢＲ１，ＳＢＲ４および変性ＳＢＲ５は油展品であるため、正味のゴム量を括弧内に併記した。また、表３の共通処方成分の配合量は、表１，２に示すジエン系ゴム１００質量部に対する質量部として記載した。また、シリカおよびカーボンブラックの合計量を表１，２の「ＣＢ＋シリカ（質量部）」の欄に記載し、シリカおよびカーボンブラックの合計に対するシリカの質量比を「シリカ質量比（質量％）」の欄に記載した。さらに、ジエン系ゴムの平均ガラス転移温度を「ゴムの平均Ｔｇ ℃」の欄に記載し、ジエン系ゴム中のブタジエン重合成分における平均ビニル含量を「ブタジエン重合成分の平均ビニル含量（質量％）」の欄に記載した。 EXAMPLES Hereinafter, the present invention will be further explained with reference to Examples, but the scope of the present invention is not limited to these Examples.
In preparing 15 types of tire rubber compositions (standard example, Examples 1 to 6, Comparative Examples 1 to 8) having the formulations shown in Tables 1 and 2 using the compounding agents shown in Table 3 as a common formulation, each The ingredients except sulfur and vulcanization accelerator were weighed and kneaded for 5 minutes in a 1.8 L internal mixer, and then the masterbatch was discharged and cooled to room temperature. This masterbatch was placed in a 1.8L closed mixer, and sulfur and a vulcanization accelerator were added and mixed to obtain a tire rubber composition. In Tables 1 and 2, since modified SBR1, SBR4 and modified SBR5 are oil-extended products, the net rubber amount is also written in parentheses. Further, the blending amounts of the common prescription components in Table 3 are expressed as parts by mass based on 100 parts by mass of the diene rubber shown in Tables 1 and 2. In addition, the total amount of silica and carbon black is recorded in the "CB + Silica (parts by mass)" column of Tables 1 and 2, and the mass ratio of silica to the total of silica and carbon black is "Silica mass ratio (mass %)". It was written in the column. Furthermore, the average glass transition temperature of the diene rubber is written in the column "Average Tg of rubber ℃", and the average vinyl content in the butadiene polymerization component in the diene rubber is "average vinyl content (mass%) of the butadiene polymerization component". It was written in the column.
得られた１５種類のゴム組成物を所定のモールドを用いて、１６０℃で３０分間加硫して加硫ゴム試験片を作製した。得られた加硫ゴム試験片を使用し、初期の３００％変形時の引張応力Ｍｉおよび５０℃、１０００時間加熱処理した後の３００％変形時の引張応力Ｍａを以下の測定方法により評価した。
The obtained 15 types of rubber compositions were vulcanized at 160° C. for 30 minutes using a predetermined mold to produce vulcanized rubber test pieces. Using the obtained vulcanized rubber test piece, the initial tensile stress Mi at 300% deformation and the tensile stress Ma at 300% deformation after heat treatment at 50° C. for 1000 hours were evaluated by the following measuring method.
引張り特性（３００％変形時の引張応力）
上記で得られた加硫ゴム試験片、および５０℃、１０００時間加熱処理した後の加硫ゴム試験片を使用し、ＪＩＳ Ｋ６２５１に準拠して、ダンベル型ＪＩＳ３号形試験片を作製し、室温（２０℃）で５００ｍｍ／分の引張り速度で引張り試験を行い、３００％変形時の引張応力（ＭｉおよびＭａ）を測定し、（Ｍａ－Ｍｉ）／Ｍｉの値を算出した。得られた結果は、表１、２の「Ｍ３００の変化率」の欄に記載した。この値が小さいほど熱老化後の３００％変形時の引張応力の変化が小さく熱老化促進試験における劣化が抑制されていることを意味する。 Tensile properties (tensile stress at 300% deformation)
Using the vulcanized rubber test piece obtained above and the vulcanized rubber test piece heat-treated at 50°C for 1000 hours, dumbbell-shaped JIS No. 3 test pieces were prepared in accordance with JIS K6251, A tensile test was conducted at (20° C.) at a tensile speed of 500 mm/min, the tensile stress (Mi and Ma) at 300% deformation was measured, and the value of (Ma-Mi)/Mi was calculated. The obtained results are listed in the "M300 change rate" column of Tables 1 and 2. The smaller this value is, the smaller the change in tensile stress at 300% deformation after heat aging is, meaning that deterioration in accelerated heat aging tests is suppressed.
上記で得られた加硫ゴム試験片、および５０℃、１０００時間加熱処理した後の加硫ゴム試験片を使用し、ＪＩＳ Ｋ６２５１に準拠して、ダンベル型ＪＩＳ３号形試験片を作製し、室温（２０℃）で５００ｍｍ／分の引張り速度で引張り試験を行い、３００％変形時の引張応力（ＭｉおよびＭａ）を測定し、（Ｍａ－Ｍｉ）／Ｍｉの値を算出した。得られた結果は、表１、２の「Ｍ３００の変化率」の欄に記載した。この値が小さいほど熱老化後の３００％変形時の引張応力の変化が小さく熱老化促進試験における劣化が抑制されていることを意味する。 Tensile properties (tensile stress at 300% deformation)
Using the vulcanized rubber test piece obtained above and the vulcanized rubber test piece heat-treated at 50°C for 1000 hours, dumbbell-shaped JIS No. 3 test pieces were prepared in accordance with JIS K6251, A tensile test was conducted at (20° C.) at a tensile speed of 500 mm/min, the tensile stress (Mi and Ma) at 300% deformation was measured, and the value of (Ma-Mi)/Mi was calculated. The obtained results are listed in the "M300 change rate" column of Tables 1 and 2. The smaller this value is, the smaller the change in tensile stress at 300% deformation after heat aging is, meaning that deterioration in accelerated heat aging tests is suppressed.
また、１５種類のゴム組成物をキャップトレッドに用いたサイズ（２２５／６０Ｒ１８）の空気入りタイヤを加硫成形した。それぞれの空気入りタイヤを用いて、耐摩耗性、雪上性能および長期間使用後のウェットグリップ性能を下記に示す方法により評価した。
In addition, pneumatic tires of size (225/60R18) using 15 types of rubber compositions for the cap tread were vulcanized and molded. Using each pneumatic tire, abrasion resistance, on-snow performance, and wet grip performance after long-term use were evaluated by the methods shown below.
耐摩耗性
得られた空気入りタイヤをリムサイズ１８×７ＪＪのホイールに組付け、空気圧２２０ｋＰａを充填し国産２．５リットルクラスの試験車両に装着し、テストコースの１周５ｋｍの周回路の乾燥路面を速度８０ｋｍ／時で連続して１０周走行した。その後トレッド面における摩耗の状態を目視により観察し、標準例を１００として点数付け評価した。得られた結果を表１，２の「耐摩耗性」の欄に示した。評価の値が大きいほど、耐摩耗性が良いことを示す。 Wear resistance The obtained pneumatic tire was assembled on a wheel with a rim size of 18 x 7 JJ, filled with air pressure of 220 kPa, and installed on a domestically produced 2.5 liter class test vehicle, and was tested on the dry road surface of a 5 km circuit of the test course. The vehicle ran 10 laps continuously at a speed of 80 km/hour. Thereafter, the state of wear on the tread surface was visually observed, and the standard example was evaluated using a score of 100. The obtained results are shown in the "Abrasion Resistance" column of Tables 1 and 2. The larger the evaluation value, the better the wear resistance.
得られた空気入りタイヤをリムサイズ１８×７ＪＪのホイールに組付け、空気圧２２０ｋＰａを充填し国産２．５リットルクラスの試験車両に装着し、テストコースの１周５ｋｍの周回路の乾燥路面を速度８０ｋｍ／時で連続して１０周走行した。その後トレッド面における摩耗の状態を目視により観察し、標準例を１００として点数付け評価した。得られた結果を表１，２の「耐摩耗性」の欄に示した。評価の値が大きいほど、耐摩耗性が良いことを示す。 Wear resistance The obtained pneumatic tire was assembled on a wheel with a rim size of 18 x 7 JJ, filled with air pressure of 220 kPa, and installed on a domestically produced 2.5 liter class test vehicle, and was tested on the dry road surface of a 5 km circuit of the test course. The vehicle ran 10 laps continuously at a speed of 80 km/hour. Thereafter, the state of wear on the tread surface was visually observed, and the standard example was evaluated using a score of 100. The obtained results are shown in the "Abrasion Resistance" column of Tables 1 and 2. The larger the evaluation value, the better the wear resistance.
雪上性能
得られた空気入りタイヤをリムサイズ１８×７ＪＪのホイールに組付け、国産２．５リットルクラスの試験車両に装着し、空気圧２００ｋＰａの条件で積雪状態にした１周２．６ｋｍのテストコースを実車走行させ、そのときの操縦安定性を専門パネラー３名による感応評価により、標準例を１００として点数付け評価した。得られた結果を表１，２の「雪上性能」の欄に示した。評価の値が大きいほど、積雪路面における雪上性能（操縦安定性）が優れていることを意味する。 Performance on snow The obtained pneumatic tire was assembled onto a wheel with a rim size of 18 x 7JJ, mounted on a domestically produced 2.5 liter class test vehicle, and the tire was driven around a 2.6km test course in snowy conditions at an air pressure of 200kPa. The vehicle was driven in an actual vehicle, and three expert panelists evaluated the steering stability using a score rating of 100 for the standard example. The obtained results are shown in the "Snow performance" column of Tables 1 and 2. The larger the evaluation value, the better the performance on snow (steering stability) on snowy roads.
得られた空気入りタイヤをリムサイズ１８×７ＪＪのホイールに組付け、国産２．５リットルクラスの試験車両に装着し、空気圧２００ｋＰａの条件で積雪状態にした１周２．６ｋｍのテストコースを実車走行させ、そのときの操縦安定性を専門パネラー３名による感応評価により、標準例を１００として点数付け評価した。得られた結果を表１，２の「雪上性能」の欄に示した。評価の値が大きいほど、積雪路面における雪上性能（操縦安定性）が優れていることを意味する。 Performance on snow The obtained pneumatic tire was assembled onto a wheel with a rim size of 18 x 7JJ, mounted on a domestically produced 2.5 liter class test vehicle, and the tire was driven around a 2.6km test course in snowy conditions at an air pressure of 200kPa. The vehicle was driven in an actual vehicle, and three expert panelists evaluated the steering stability using a score rating of 100 for the standard example. The obtained results are shown in the "Snow performance" column of Tables 1 and 2. The larger the evaluation value, the better the performance on snow (steering stability) on snowy roads.
長期間使用後のウェットグリップ性能
得られた空気入りタイヤをリムサイズ１８×７ＪＪのホイールに組付け、試験車両に装着し、２０００ｋｍの実車走行を行った。走行試験後の空気入りタイヤをリムサイズ１８×７ＪＪのホイールに組付け、国産２．５リットルクラスの試験車両に装着し、空気圧２２０ｋＰａの条件で湿潤路面からなる１周２．６ｋｍのテストコースを実車走行させ、そのときの操縦安定性を専門パネラー３名による感応評価により、標準例を１００として点数付け評価した。得られた結果を表１，２の「長期ウェット性能」の欄に示した。評価の値が大きいほど、長期間使用後のウェットグリップ性能が優れていることを意味する。 Wet grip performance after long-term use The obtained pneumatic tire was assembled onto a wheel with a rim size of 18 x 7JJ, mounted on a test vehicle, and the vehicle was driven for 2000 km. After the running test, the pneumatic tires were assembled onto wheels with a rim size of 18 x 7 JJ, mounted on a domestically produced 2.5 liter class test vehicle, and the actual vehicle was driven around a 2.6 km test course with a wet road surface at an air pressure of 220 kPa. The vehicle was run, and the steering stability at that time was evaluated by sensitivity evaluation by three expert panelists, with the standard example being 100. The obtained results are shown in the "long-term wet performance" column of Tables 1 and 2. The larger the evaluation value, the better the wet grip performance after long-term use.
得られた空気入りタイヤをリムサイズ１８×７ＪＪのホイールに組付け、試験車両に装着し、２０００ｋｍの実車走行を行った。走行試験後の空気入りタイヤをリムサイズ１８×７ＪＪのホイールに組付け、国産２．５リットルクラスの試験車両に装着し、空気圧２２０ｋＰａの条件で湿潤路面からなる１周２．６ｋｍのテストコースを実車走行させ、そのときの操縦安定性を専門パネラー３名による感応評価により、標準例を１００として点数付け評価した。得られた結果を表１，２の「長期ウェット性能」の欄に示した。評価の値が大きいほど、長期間使用後のウェットグリップ性能が優れていることを意味する。 Wet grip performance after long-term use The obtained pneumatic tire was assembled onto a wheel with a rim size of 18 x 7JJ, mounted on a test vehicle, and the vehicle was driven for 2000 km. After the running test, the pneumatic tires were assembled onto wheels with a rim size of 18 x 7 JJ, mounted on a domestically produced 2.5 liter class test vehicle, and the actual vehicle was driven around a 2.6 km test course with a wet road surface at an air pressure of 220 kPa. The vehicle was run, and the steering stability at that time was evaluated by sensitivity evaluation by three expert panelists, with the standard example being 100. The obtained results are shown in the "long-term wet performance" column of Tables 1 and 2. The larger the evaluation value, the better the wet grip performance after long-term use.
なお、表１～２において使用した原材料の種類を下記に示す。
・変性ＳＢＲ１：ヒドロキシ基で変性された末端変性溶液重合スチレンブタジエンゴム、旭化成社製ＴＵＦＤＥＮＥ Ｅ５８１、スチレン単位含有量が３６質量％、ビニル単位含有量が４１質量％、ガラス転移温度（Ｔｇ）が－３４℃、油展オイルの含有量が２７．２７質量％。
・ＳＢＲ２：未変性の乳化重合スチレンブタジエンゴム、日本ゼオン社製Ｎｉｐｏｌ １５０２、スチレン単位含有量が２４質量％、ビニル単位含有量が４２質量％、ガラス転移温度（Ｔｇ）が－６０℃、非油展品。
・変性ＳＢＲ３：ヒドロキシ基で変性された末端変性溶液重合スチレンブタジエンゴム、日本ゼオン社製Ｎｉｐｏｌ ＮＳ６１２、スチレン単位含有量が１５質量％、ビニル単位含有量が３１質量％、ガラス転移温度（Ｔｇ）が－６１℃、非油展品。
・ＳＢＲ４：未変性の溶液重合スチレンブタジエンゴム、日本ゼオン社製Ｎｉｐｏｌ ＮＳ５２２、スチレン単位含有量が３８質量％、ビニル単位含有量が３９質量％、ガラス転移温度（Ｔｇ）が－２３℃、油展オイルの含有量が２７．２７質量％。
・変性ＳＢＲ５：グリシジルアミン基で変性された末端変性溶液重合スチレンブタジエンゴム、旭化成社製ＴＵＦＤＥＮＥ Ｆ３４２０、スチレン単位含有量が３６質量％、ビニル単位含有量が４１質量％、ガラス転移温度（Ｔｇ）が－２７℃、油展オイルの含有量が１６．６７質量％。
・ＢＲ：ブタジエンゴム、日本ゼオン社製Ｎｉｐｏｌ ＢＲ１２２０、ガラス転移温度（Ｔｇ）が－１０６℃
・ＮＲ：天然ゴム、ＰＴ．ＫＩＲＡＮＡ ＳＡＰＴＡ社製ＳＩＲ２０、ガラス転移温度（Ｔｇ）が－６１℃
・ＣＢ１：カーボンブラック、東海カーボン社製シースト７ＨＭ
・ＣＢ２：カーボンブラック、ＯＣＩ Ｃｏｍｐａｎｙ Ｌｔｄ．製ＤＡＳＨ ＢＬＡＣＫ Ｎ１３４
・シリカ１：Ｅｖｏｎｉｋ社製ＵＬＴＲＡＳＩＬ ＶＮ３ＧＲ。
・シリカ２：Ｅｖｏｎｉｋ社製ＵＬＴＲＡＳＩＬ ７０００ＧＲ。
・カップリング剤：シランカップリング剤、Ｅｖｏｎｉｋ社製Ｓｉ６９、ビス（３－トリエトキシシリルプロピル）テトラスルフィド
・アロマオイル：昭和シェル石油社製エキストラクト４号Ｓ The types of raw materials used in Tables 1 and 2 are shown below.
・Modified SBR1: terminally modified solution polymerized styrene-butadiene rubber modified with hydroxyl groups, TUFDENE E581 manufactured by Asahi Kasei, styrene unit content 36% by mass, vinyl unit content 41% by mass, glass transition temperature (Tg) - 34° C., the content of oil extension oil was 27.27% by mass.
・SBR2: Unmodified emulsion polymerized styrene butadiene rubber, Nipol 1502 manufactured by Nippon Zeon, styrene unit content 24% by mass, vinyl unit content 42% by mass, glass transition temperature (Tg) -60°C, non-oil Exhibit.
・Modified SBR3: Terminal modified solution polymerized styrene-butadiene rubber modified with hydroxy groups, Nipol NS612 manufactured by Nippon Zeon, styrene unit content 15% by mass, vinyl unit content 31% by mass, glass transition temperature (Tg) -61℃, non-oil-extended product.
・SBR4: Unmodified solution polymerized styrene-butadiene rubber, Nipol NS522 manufactured by Nippon Zeon, styrene unit content 38% by mass, vinyl unit content 39% by mass, glass transition temperature (Tg) -23°C, oil extension Oil content is 27.27% by mass.
・Modified SBR5: terminally modified solution polymerized styrene-butadiene rubber modified with glycidylamine groups, TUFDENE F3420 manufactured by Asahi Kasei, styrene unit content 36% by mass, vinyl unit content 41% by mass, glass transition temperature (Tg) -27°C, the content of oil extension oil is 16.67% by mass.
・BR: Butadiene rubber, Nipol BR1220 manufactured by Nippon Zeon, glass transition temperature (Tg) is -106°C
・NR: Natural rubber, PT. SIR20 manufactured by KIRANA SAPTA, glass transition temperature (Tg) is -61℃
・CB1: Carbon black, Seast 7HM manufactured by Tokai Carbon Co., Ltd.
・CB2: Carbon black, OCI Company Ltd. Manufactured by DASH BLACK N134
- Silica 1: ULTRASIL VN3GR manufactured by Evonik.
- Silica 2: ULTRASIL 7000GR manufactured by Evonik.
・Coupling agent: Silane coupling agent, Evonik Si69, bis(3-triethoxysilylpropyl) tetrasulfide ・Aroma oil: Showa Shell Sekiyu Extract No. 4 S
・変性ＳＢＲ１：ヒドロキシ基で変性された末端変性溶液重合スチレンブタジエンゴム、旭化成社製ＴＵＦＤＥＮＥ Ｅ５８１、スチレン単位含有量が３６質量％、ビニル単位含有量が４１質量％、ガラス転移温度（Ｔｇ）が－３４℃、油展オイルの含有量が２７．２７質量％。
・ＳＢＲ２：未変性の乳化重合スチレンブタジエンゴム、日本ゼオン社製Ｎｉｐｏｌ １５０２、スチレン単位含有量が２４質量％、ビニル単位含有量が４２質量％、ガラス転移温度（Ｔｇ）が－６０℃、非油展品。
・変性ＳＢＲ３：ヒドロキシ基で変性された末端変性溶液重合スチレンブタジエンゴム、日本ゼオン社製Ｎｉｐｏｌ ＮＳ６１２、スチレン単位含有量が１５質量％、ビニル単位含有量が３１質量％、ガラス転移温度（Ｔｇ）が－６１℃、非油展品。
・ＳＢＲ４：未変性の溶液重合スチレンブタジエンゴム、日本ゼオン社製Ｎｉｐｏｌ ＮＳ５２２、スチレン単位含有量が３８質量％、ビニル単位含有量が３９質量％、ガラス転移温度（Ｔｇ）が－２３℃、油展オイルの含有量が２７．２７質量％。
・変性ＳＢＲ５：グリシジルアミン基で変性された末端変性溶液重合スチレンブタジエンゴム、旭化成社製ＴＵＦＤＥＮＥ Ｆ３４２０、スチレン単位含有量が３６質量％、ビニル単位含有量が４１質量％、ガラス転移温度（Ｔｇ）が－２７℃、油展オイルの含有量が１６．６７質量％。
・ＢＲ：ブタジエンゴム、日本ゼオン社製Ｎｉｐｏｌ ＢＲ１２２０、ガラス転移温度（Ｔｇ）が－１０６℃
・ＮＲ：天然ゴム、ＰＴ．ＫＩＲＡＮＡ ＳＡＰＴＡ社製ＳＩＲ２０、ガラス転移温度（Ｔｇ）が－６１℃
・ＣＢ１：カーボンブラック、東海カーボン社製シースト７ＨＭ
・ＣＢ２：カーボンブラック、ＯＣＩ Ｃｏｍｐａｎｙ Ｌｔｄ．製ＤＡＳＨ ＢＬＡＣＫ Ｎ１３４
・シリカ１：Ｅｖｏｎｉｋ社製ＵＬＴＲＡＳＩＬ ＶＮ３ＧＲ。
・シリカ２：Ｅｖｏｎｉｋ社製ＵＬＴＲＡＳＩＬ ７０００ＧＲ。
・カップリング剤：シランカップリング剤、Ｅｖｏｎｉｋ社製Ｓｉ６９、ビス（３－トリエトキシシリルプロピル）テトラスルフィド
・アロマオイル：昭和シェル石油社製エキストラクト４号Ｓ The types of raw materials used in Tables 1 and 2 are shown below.
・Modified SBR1: terminally modified solution polymerized styrene-butadiene rubber modified with hydroxyl groups, TUFDENE E581 manufactured by Asahi Kasei, styrene unit content 36% by mass, vinyl unit content 41% by mass, glass transition temperature (Tg) - 34° C., the content of oil extension oil was 27.27% by mass.
・SBR2: Unmodified emulsion polymerized styrene butadiene rubber, Nipol 1502 manufactured by Nippon Zeon, styrene unit content 24% by mass, vinyl unit content 42% by mass, glass transition temperature (Tg) -60°C, non-oil Exhibit.
・Modified SBR3: Terminal modified solution polymerized styrene-butadiene rubber modified with hydroxy groups, Nipol NS612 manufactured by Nippon Zeon, styrene unit content 15% by mass, vinyl unit content 31% by mass, glass transition temperature (Tg) -61℃, non-oil-extended product.
・SBR4: Unmodified solution polymerized styrene-butadiene rubber, Nipol NS522 manufactured by Nippon Zeon, styrene unit content 38% by mass, vinyl unit content 39% by mass, glass transition temperature (Tg) -23°C, oil extension Oil content is 27.27% by mass.
・Modified SBR5: terminally modified solution polymerized styrene-butadiene rubber modified with glycidylamine groups, TUFDENE F3420 manufactured by Asahi Kasei, styrene unit content 36% by mass, vinyl unit content 41% by mass, glass transition temperature (Tg) -27°C, the content of oil extension oil is 16.67% by mass.
・BR: Butadiene rubber, Nipol BR1220 manufactured by Nippon Zeon, glass transition temperature (Tg) is -106°C
・NR: Natural rubber, PT. SIR20 manufactured by KIRANA SAPTA, glass transition temperature (Tg) is -61℃
・CB1: Carbon black, Seast 7HM manufactured by Tokai Carbon Co., Ltd.
・CB2: Carbon black, OCI Company Ltd. Manufactured by DASH BLACK N134
- Silica 1: ULTRASIL VN3GR manufactured by Evonik.
- Silica 2: ULTRASIL 7000GR manufactured by Evonik.
・Coupling agent: Silane coupling agent, Evonik Si69, bis(3-triethoxysilylpropyl) tetrasulfide ・Aroma oil: Showa Shell Sekiyu Extract No. 4 S
なお、表３において使用した原材料の種類を下記に示す。
・老化防止剤：Ｋｏｒｅａ Ｋｕｍｈｏ Ｐｅｔｒｏｃｈｅｍｉｃａｌ社製６ＰＰＤ
・ワックス：日本精蝉社製ＯＺＯＡＣＥ－００１５Ａ
・酸化亜鉛：正同化学工業社製酸化亜鉛３種
・ステアリン酸：日油社製ビーズステアリン酸
・加硫促進剤１：大内新興化学工業社製ノクセラーＣＺ－Ｇ
・加硫促進剤２：住友化学社製ソクシノールＤ－Ｇ
・硫黄：鶴見化学工業社製金華印油入微粉硫黄 The types of raw materials used in Table 3 are shown below.
・Anti-aging agent: 6PPD manufactured by Korea Kumho Petrochemical
・Wax: OZOACE-0015A manufactured by Nippon Seiseisha
・Zinc oxide: 3 types of zinc oxide manufactured by Seido Chemical Industry Co., Ltd. ・Stearic acid: Bead stearic acid manufactured by NOF Corporation ・Vulcanization accelerator 1: Noxeler CZ-G manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
・Vulcanization accelerator 2: Soccinol DG manufactured by Sumitomo Chemical Co., Ltd.
・Sulfur: Fine powder sulfur with Kinka seal oil manufactured by Tsurumi Chemical Industry Co., Ltd.
・老化防止剤：Ｋｏｒｅａ Ｋｕｍｈｏ Ｐｅｔｒｏｃｈｅｍｉｃａｌ社製６ＰＰＤ
・ワックス：日本精蝉社製ＯＺＯＡＣＥ－００１５Ａ
・酸化亜鉛：正同化学工業社製酸化亜鉛３種
・ステアリン酸：日油社製ビーズステアリン酸
・加硫促進剤１：大内新興化学工業社製ノクセラーＣＺ－Ｇ
・加硫促進剤２：住友化学社製ソクシノールＤ－Ｇ
・硫黄：鶴見化学工業社製金華印油入微粉硫黄 The types of raw materials used in Table 3 are shown below.
・Anti-aging agent: 6PPD manufactured by Korea Kumho Petrochemical
・Wax: OZOACE-0015A manufactured by Nippon Seiseisha
・Zinc oxide: 3 types of zinc oxide manufactured by Seido Chemical Industry Co., Ltd. ・Stearic acid: Bead stearic acid manufactured by NOF Corporation ・Vulcanization accelerator 1: Noxeler CZ-G manufactured by Ouchi Shinko Chemical Industry Co., Ltd.
・Vulcanization accelerator 2: Soccinol DG manufactured by Sumitomo Chemical Co., Ltd.
・Sulfur: Fine powder sulfur with Kinka seal oil manufactured by Tsurumi Chemical Industry Co., Ltd.
表１，２から明らかなように実施例１～６のタイヤ用ゴム組成物は、雪上性能および長期使用後のウェット性能と耐摩耗性とのバランスを従来レベルよりも向上させることができる。
As is clear from Tables 1 and 2, the tire rubber compositions of Examples 1 to 6 can improve performance on snow and the balance between wet performance and abrasion resistance after long-term use compared to conventional levels.
比較例１のゴム組成物は、ジエン系ゴムの平均ガラス転移温度が－５０℃より高いので、耐摩耗性および雪上性能が悪化する。
比較例２のゴム組成物は、ジエン系ゴムの平均ガラス転移温度が－７０℃より低いので、長期使用後のウェットグリップ性能が悪化する。
比較例３のゴム組成物は、無機充填剤中のシリカの重量割合が６０質量％未満、加熱処理した後の３００％変形時の引張応力の変化率が０．３より大きいので、長期使用後のウェットグリップ性能が悪化する。
比較例４のゴム組成物は、無機充填剤中のシリカの重量割合が６０質量％未満、加熱処理した後の３００％変形時の引張応力の変化率が０．３より大きいので、長期使用後のウェットグリップ性能が悪化する。
比較例５のゴム組成物は、無機充填剤が７０質量部未満なので、耐摩耗性および長期使用後のウェットグリップ性能が悪化する。
比較例６のゴム組成物は、無機充填剤中シリカが６０質量％未満であるので、雪上性能および長期使用後のウェットグリップ性能が悪化する。
比較例７のゴム組成物は、スチレンブタジエンゴム（ＳＢＲ４）が末端変性されておらず、スチレン単位含有量が３７質量％を超えるので雪上性能および長期使用後のウェットグリップ性能が悪化する。
比較例８のゴム組成物は、末端変性スチレンブタジエンゴム（変性ＳＢＲ５）の油展オイルが２３質量％未満なので耐摩耗性が悪化する。 In the rubber composition of Comparative Example 1, the average glass transition temperature of the diene rubber is higher than -50°C, so the abrasion resistance and on-snow performance deteriorate.
In the rubber composition of Comparative Example 2, the average glass transition temperature of the diene rubber is lower than -70°C, so the wet grip performance after long-term use deteriorates.
In the rubber composition of Comparative Example 3, the weight ratio of silica in the inorganic filler is less than 60% by mass, and the rate of change in tensile stress at 300% deformation after heat treatment is greater than 0.3, so it is difficult to use after long-term use. Wet grip performance deteriorates.
In the rubber composition of Comparative Example 4, the weight ratio of silica in the inorganic filler is less than 60% by mass, and the rate of change in tensile stress at 300% deformation after heat treatment is greater than 0.3, so it is difficult to use after long-term use. Wet grip performance deteriorates.
Since the rubber composition of Comparative Example 5 contains less than 70 parts by mass of inorganic filler, the abrasion resistance and wet grip performance after long-term use deteriorate.
In the rubber composition of Comparative Example 6, since the silica content in the inorganic filler is less than 60% by mass, on-snow performance and wet grip performance after long-term use deteriorate.
In the rubber composition of Comparative Example 7, the styrene-butadiene rubber (SBR4) is not terminally modified and the styrene unit content exceeds 37% by mass, resulting in poor on-snow performance and wet grip performance after long-term use.
In the rubber composition of Comparative Example 8, the abrasion resistance deteriorates because the oil extending oil in the terminal-modified styrene-butadiene rubber (modified SBR5) is less than 23% by mass.
比較例２のゴム組成物は、ジエン系ゴムの平均ガラス転移温度が－７０℃より低いので、長期使用後のウェットグリップ性能が悪化する。
比較例３のゴム組成物は、無機充填剤中のシリカの重量割合が６０質量％未満、加熱処理した後の３００％変形時の引張応力の変化率が０．３より大きいので、長期使用後のウェットグリップ性能が悪化する。
比較例４のゴム組成物は、無機充填剤中のシリカの重量割合が６０質量％未満、加熱処理した後の３００％変形時の引張応力の変化率が０．３より大きいので、長期使用後のウェットグリップ性能が悪化する。
比較例５のゴム組成物は、無機充填剤が７０質量部未満なので、耐摩耗性および長期使用後のウェットグリップ性能が悪化する。
比較例６のゴム組成物は、無機充填剤中シリカが６０質量％未満であるので、雪上性能および長期使用後のウェットグリップ性能が悪化する。
比較例７のゴム組成物は、スチレンブタジエンゴム（ＳＢＲ４）が末端変性されておらず、スチレン単位含有量が３７質量％を超えるので雪上性能および長期使用後のウェットグリップ性能が悪化する。
比較例８のゴム組成物は、末端変性スチレンブタジエンゴム（変性ＳＢＲ５）の油展オイルが２３質量％未満なので耐摩耗性が悪化する。 In the rubber composition of Comparative Example 1, the average glass transition temperature of the diene rubber is higher than -50°C, so the abrasion resistance and on-snow performance deteriorate.
In the rubber composition of Comparative Example 2, the average glass transition temperature of the diene rubber is lower than -70°C, so the wet grip performance after long-term use deteriorates.
In the rubber composition of Comparative Example 3, the weight ratio of silica in the inorganic filler is less than 60% by mass, and the rate of change in tensile stress at 300% deformation after heat treatment is greater than 0.3, so it is difficult to use after long-term use. Wet grip performance deteriorates.
In the rubber composition of Comparative Example 4, the weight ratio of silica in the inorganic filler is less than 60% by mass, and the rate of change in tensile stress at 300% deformation after heat treatment is greater than 0.3, so it is difficult to use after long-term use. Wet grip performance deteriorates.
Since the rubber composition of Comparative Example 5 contains less than 70 parts by mass of inorganic filler, the abrasion resistance and wet grip performance after long-term use deteriorate.
In the rubber composition of Comparative Example 6, since the silica content in the inorganic filler is less than 60% by mass, on-snow performance and wet grip performance after long-term use deteriorate.
In the rubber composition of Comparative Example 7, the styrene-butadiene rubber (SBR4) is not terminally modified and the styrene unit content exceeds 37% by mass, resulting in poor on-snow performance and wet grip performance after long-term use.
In the rubber composition of Comparative Example 8, the abrasion resistance deteriorates because the oil extending oil in the terminal-modified styrene-butadiene rubber (modified SBR5) is less than 23% by mass.
Claims (4)
- 末端変性スチレンブタジエンゴムを３０～６０質量％含み、平均ガラス転移温度が－７０℃～－５５℃であるジエン系ゴム１００質量部に、シリカおよびカーボンブラックを含む無機充填剤を７０質量部以上配合し、前記無機充填剤中シリカが６０質量％以上であって、前記末端変性スチレンブタジエンゴムが油展オイルを２３質量％以上含有し、そのスチレン単位含有量が３７質量％以下であるゴム組成物であって、その硬化物の３００％変形時の引張応力Ｍｉおよび前記硬化物を５０℃、１０００時間加熱処理した後の３００％変形時の引張応力Ｍａが以下の式；
（Ｍａ－Ｍｉ）／Ｍｉ ≦ ０．３
を満たすことを特徴とするタイヤ用ゴム組成物。 70 parts by mass or more of an inorganic filler containing silica and carbon black is blended into 100 parts by mass of a diene rubber containing 30 to 60 mass% of terminally modified styrene-butadiene rubber and having an average glass transition temperature of -70 to -55 °C. and a rubber composition in which silica in the inorganic filler is 60% by mass or more, the terminal-modified styrene-butadiene rubber contains 23% by mass or more of oil-extended oil, and the styrene unit content is 37% by mass or less. The tensile stress Mi at 300% deformation of the cured product and the tensile stress Ma at 300% deformation after heat treating the cured product at 50° C. for 1000 hours are expressed by the following formula;
(Ma-Mi)/Mi ≦ 0.3
A rubber composition for tires characterized by satisfying the following. - 前記ジエン系ゴム中のブタジエン重合成分における、平均ビニル含量が４０質量％以下である請求項１に記載のタイヤ用ゴム組成物。 The rubber composition for tires according to claim 1, wherein the average vinyl content in the butadiene polymerization component in the diene rubber is 40% by mass or less.
- 前記ジエン系ゴム１００質量部に、前記無機充填剤を７０質量部以上９０質量部以下配合してなる請求項１または２に記載のタイヤ用ゴム組成物。 The rubber composition for a tire according to claim 1 or 2, wherein the inorganic filler is blended in 70 parts by mass or more and 90 parts by mass or less with 100 parts by mass of the diene rubber.
- 前記無機充填剤中シリカが６０質量％以上９０質量％以下である請求項１～３のいずれかに記載のタイヤ用ゴム組成物。 The rubber composition for tires according to any one of claims 1 to 3, wherein the inorganic filler contains silica in an amount of 60% by mass or more and 90% by mass or less.
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| JP2022-059696 | 2022-03-31 | ||
| JP2022059696A JP7473825B2 (en) | 2022-03-31 | 2022-03-31 | Rubber composition for tires |
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| PCT/JP2023/012811 WO2023190688A1 (en) | 2022-03-31 | 2023-03-29 | Rubber composition for tires |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014210829A (en) * | 2013-04-17 | 2014-11-13 | 横浜ゴム株式会社 | Rubber composition and pneumatic tire using the same |
| WO2015186755A1 (en) * | 2014-06-04 | 2015-12-10 | 横浜ゴム株式会社 | Tire tread rubber composition |
| WO2019163519A1 (en) * | 2018-02-26 | 2019-08-29 | 横浜ゴム株式会社 | Rubber composition and pneumatic tire obtained using same |
| WO2020110941A1 (en) * | 2018-11-30 | 2020-06-04 | 横浜ゴム株式会社 | Rubber composition for tire |
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| JP5376008B2 (en) | 2012-04-24 | 2013-12-25 | 横浜ゴム株式会社 | Rubber composition for tire |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014210829A (en) * | 2013-04-17 | 2014-11-13 | 横浜ゴム株式会社 | Rubber composition and pneumatic tire using the same |
| WO2015186755A1 (en) * | 2014-06-04 | 2015-12-10 | 横浜ゴム株式会社 | Tire tread rubber composition |
| WO2019163519A1 (en) * | 2018-02-26 | 2019-08-29 | 横浜ゴム株式会社 | Rubber composition and pneumatic tire obtained using same |
| WO2020110941A1 (en) * | 2018-11-30 | 2020-06-04 | 横浜ゴム株式会社 | Rubber composition for tire |
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| JP7473825B2 (en) | 2024-04-24 |
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