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WO2025109840A1 - Pneumatique - Google Patents

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Publication number
WO2025109840A1
WO2025109840A1 PCT/JP2024/032423 JP2024032423W WO2025109840A1 WO 2025109840 A1 WO2025109840 A1 WO 2025109840A1 JP 2024032423 W JP2024032423 W JP 2024032423W WO 2025109840 A1 WO2025109840 A1 WO 2025109840A1
Authority
WO
WIPO (PCT)
Prior art keywords
mass
rubber
silane coupling
coupling agent
parts
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2024/032423
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English (en)
Japanese (ja)
Inventor
直也 大島
真基 飯田
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bridgestone Corp
Original Assignee
Bridgestone Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bridgestone Corp filed Critical Bridgestone Corp
Publication of WO2025109840A1 publication Critical patent/WO2025109840A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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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
    • 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
    • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
    • B60C9/18—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers
    • B60C9/20—Structure or arrangement of belts or breakers, crown-reinforcing or cushioning layers built-up from rubberised plies each having all cords arranged substantially parallel
    • 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
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds
    • C08K3/36—Silica
    • 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
    • C08K5/00—Use of organic ingredients
    • C08K5/54—Silicon-containing compounds
    • C08K5/548—Silicon-containing compounds containing sulfur
    • 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
    • C08K9/00—Use of pretreated ingredients
    • C08K9/04—Ingredients treated with organic substances
    • C08K9/06—Ingredients treated with organic substances with silicon-containing compounds
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L25/00—Compositions of, homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Compositions of derivatives of such polymers
    • C08L25/02—Homopolymers or copolymers of hydrocarbons
    • C08L25/04—Homopolymers or copolymers of styrene
    • C08L25/08—Copolymers of styrene
    • C08L25/10—Copolymers of styrene with conjugated dienes
    • 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 tires.
  • Patent Document 1 discloses that applying a rubber composition made by compounding a rubber component containing 70% by mass or more of natural rubber with a thermoplastic resin and a filler containing silica to the tread rubber of a tire improves the braking performance of the tire on both dry and wet road surfaces.
  • Patent Document 2 discloses a rubber composition that contains emulsion-polymerized styrene-butadiene rubber and solution-polymerized styrene-butadiene rubber, both of which have a glass transition temperature Tg of -25°C or higher, and a polymer with a low Tg, with the aim of achieving both wet grip performance and low fuel consumption performance in tires.
  • Patent Document 1 shows that while the technology described in Patent Document 1 can improve the wet grip performance of tires, the addition of a softening component resin (thermoplastic resin) reduces the rigidity of the rubber, lowering the plunger level of the tire and resulting in insufficient cut resistance. Furthermore, when attempting to supplement the cut resistance of tires, the amount of resin, which is a softening component, that can be added is limited, resulting in insufficient wet grip performance.
  • a softening component resin thermoplastic resin
  • Patent Document 2 makes it possible to achieve both wet grip performance and fuel economy to a certain extent, it is necessary to further improve wet grip performance and fuel economy.
  • the present inventors conducted research and found that wet grip performance and fuel economy can be improved by blending a silane coupling agent having a thiol group.
  • rubber compositions containing silane coupling agents having a thiol group are prone to discoloration of the appearance, such as becoming shiny black over time.
  • the present invention aims to solve the problems of the conventional technology described above, and to provide a tire that has improved wet grip performance, fuel efficiency, and wear resistance without compromising cut resistance, and that also suppresses discoloration of the exterior.
  • a tire comprising a tread rubber layer located on the outermost surface of a tread portion and a belt layer located radially inward of the tread rubber layer,
  • the tread rubber layer is made of a rubber composition containing a rubber component, a filler, and a silane coupling agent,
  • the rubber component contains a styrene-butadiene rubber (A) modified with a modifier having at least one atom of nitrogen, silicon, and tin and having a glass transition temperature of ⁇ 50° C. or lower, and an unmodified styrene-butadiene rubber (B) having a glass transition temperature 30° C.
  • A styrene-butadiene rubber
  • B unmodified styrene-butadiene rubber
  • the filler contains at least silica
  • the silane coupling agent contains at least a silane coupling agent (A) having a thiol group and a silane coupling agent (B) having a sulfide bond
  • the content of the silane coupling agent (A) is 1 to 10 parts by mass relative to 100 parts by mass of the silica
  • the total content of the silane coupling agent (A) and the silane coupling agent (B) is more than 1 part by mass and not more than 15 parts by mass relative to 100 parts by mass of the silica
  • the belt layer includes a cord having a structure formed by twisting filaments together, When the diameter of the filament constituting the cord of the belt layer is X (mm) and the tensile strength of the filament is Y (MPa), the following formula is satisfied: 4000-2000X ⁇ Y ⁇ 4500-2000X A tire characterized by satisfying the above.
  • [4] A tire according to any one of [1] to [3], in which the mass ratio (B/A) of the content of the silane coupling agent (B) to the content of the silane coupling agent (A) is 0.3 or more and less than 3.
  • the filler further contains carbon black,
  • the tire according to any one of [1] to [4], wherein a content ratio of the silica in a total amount of the silica and the carbon black is 80 mass% or more and less than 100 mass%.
  • [7] A tire according to any one of [1] to [6], in which the silane coupling agent (A) has a carbon number of 20 to 75.
  • [8] A tire according to any one of [1] to [7], in which the rubber component contains 15% by mass or more and less than 85% by mass of the styrene-butadiene rubber (A).
  • the rubber composition constituting the tread rubber layer further contains a resin,
  • the present invention provides a tire that has improved wet grip performance, fuel economy, and wear resistance without compromising cut resistance, and also suppresses discoloration of the exterior.
  • FIG. 1 is a cross-sectional view of one embodiment of a tire of the present invention.
  • the compounds described herein may be derived in whole or in part from fossil sources, from biological sources such as plant sources, from recycled sources such as used tires, or from a mixture of two or more of fossil, biological and/or renewable sources.
  • the glass transition temperature of styrene-butadiene rubber is determined in accordance with ISO 22768:2006 by recording a DSC curve while increasing the temperature within a specified temperature range, and the peak top (inflection point) of the DSC differential curve is taken as the glass transition temperature.
  • the softening point of the resin is measured in accordance with JIS-K2207-1996 (ring and ball method).
  • the weight average molecular weight of the resin is measured by gel permeation chromatography (GPC) and calculated as a polystyrene equivalent value.
  • Fig. 1 is a cross-sectional view of one embodiment of a tire of the present invention.
  • the tire 1 shown in Fig. 1 has a pair of bead portions 2, a pair of sidewall portions 3, and a tread portion 4 connected to both sidewall portions 3.
  • the tire 1 also includes a carcass 5 extending in a toroidal shape between the pair of bead portions 2 to reinforce these portions 2, 3, and 4, and a belt 6 disposed on the outer side of a crown portion of the carcass 5 in the tire radial direction.
  • the carcass 5 of the tire shown in Figure 1 is composed of one carcass ply made of multiple parallel-arranged cords covered with a coating rubber, and the carcass 5 is composed of a main body portion that extends in a toroidal shape between the bead cores 7 embedded in each of the bead portions 2, and a folded-up portion that is wound up radially outward from the inner side toward the outer side in the tire width direction around each bead core 7, but the number and structure of the plies of the carcass 5 in the tire of the present invention are not limited to this.
  • the tire belt 6 shown in FIG. 1 is made up of two belt layers 6A and 6B, but in the tire of the present invention, the number of belt layers constituting the belt 6 is not limited to this, and the number of belt layers may be three or more.
  • the belt layer is usually made up of a rubber-coated layer of metal cords (preferably steel cords) that extend at an angle to the tire equatorial plane, and the two belt layers are laminated so that the metal cords constituting the belt layers cross each other with the tire equatorial plane in between to form the belt 6.
  • the tire 1 of the present embodiment includes a tread rubber layer 8 located on the outermost surface of the tread portion 4, and belt layers 6A, 6B located on the inner side in the tire radial direction of the tread rubber layer 8.
  • the tread rubber layer 8 is made of a rubber composition containing a rubber component, a filler, and a silane coupling agent,
  • the rubber component contains a styrene-butadiene rubber (A) modified with a modifier having at least one atom of nitrogen, silicon, and tin and having a glass transition temperature of ⁇ 50° C. or lower, and an unmodified styrene-butadiene rubber (B) having a glass transition temperature 30° C.
  • the filler contains at least silica
  • the silane coupling agent contains at least a silane coupling agent (A) having a thiol group and a silane coupling agent (B) having a sulfide bond
  • the content of the silane coupling agent (A) is 1 to 10 parts by mass relative to 100 parts by mass of the silica
  • the total content of the silane coupling agent (A) and the silane coupling agent (B) is more than 1 part by mass and not more than 15 parts by mass relative to 100 parts by mass of the silica
  • the belt layers 6A and 6B include cords having a structure formed by twisting filaments together, and the filaments constituting the cords of the belt layers 6A and 6B have a diameter of X (mm) and a tensile strength of Y (MPa) that satisfies the following formula: 4000-2000X ⁇ Y ⁇ 4500-2000X
  • the present invention is characterized in that
  • the tire of the present invention may be modified in various ways as long as it comprises a tread rubber layer located on the outermost surface of the tread portion and a belt layer located radially inward of the tread rubber layer.
  • a tread rubber layer located on the outermost surface of the tread portion and a belt layer located radially inward of the tread rubber layer.
  • the tread rubber layer 8 is formed from a rubber composition containing a rubber component containing the specific modified styrene-butadiene rubber (A) and unmodified styrene-butadiene rubber (B), a filler containing silica, and a silane coupling agent, thereby improving wet grip performance, fuel efficiency, and wear resistance.
  • the silane coupling agent (A) having a thiol group has a high effect of increasing the dispersibility of silica, if the content is large, it may cause the discoloration of the tire's appearance over time.
  • the silane coupling agent (A) having a thiol group and the silane coupling agent (B) having a sulfide bond are used in combination, and the content of the silane coupling agent (A) is 10 parts by mass or less per 100 parts by mass of silica, while the total content of the silane coupling agent (A) and the silane coupling agent (B) is 15 parts by mass or less per 100 parts by mass of silica, thereby suppressing the discoloration of the appearance.
  • the cord has a structure in which filaments are twisted together, and the filaments constituting the cord have a diameter X (mm) and a tensile strength Y (MPa) that satisfies the following formula: 4000-2000X ⁇ Y ⁇ 4500-2000X
  • the strength of the belt layers 6A and 6B is improved, the plunger level is improved, and the cut resistance of the tire 1 is compensated for. Therefore, the tire 1 of the present embodiment has improved wet grip performance, fuel efficiency, and wear resistance without deteriorating cut resistance, and furthermore, discoloration of the appearance is suppressed.
  • the tread rubber layer is made of a rubber composition containing a rubber component, a filler, and a silane coupling agent.
  • a rubber component a rubber component, a filler, and a silane coupling agent.
  • the rubber component contains a styrene-butadiene rubber (A) (modified SBR) that has been modified with a modifier having at least one atom of nitrogen, silicon, and tin and has a glass transition temperature of -50°C or lower, and an unmodified styrene-butadiene rubber (B) (unmodified SBR) that has a glass transition temperature that is 30°C or higher than that of the styrene-butadiene rubber (A).
  • A styrene-butadiene rubber
  • B unmodified SBR
  • styrene-butadiene rubber (A) and styrene-butadiene rubber (B) in the rubber component can improve the wet grip performance of the tire.
  • the use of styrene-butadiene rubber (A) modified with a modifier having at least one atom of nitrogen, silicon, and tin as the rubber component can improve the dispersibility of fillers in the rubber composition, such as silica.
  • the tire of this embodiment has significantly improved low heat generation and improved dispersibility of fillers, which can also improve performance such as reinforcement, fuel efficiency, and wear resistance.
  • the styrene-butadiene rubber (A) is a styrene-butadiene rubber modified with a modifier having at least one atom of nitrogen, silicon, and tin, and has a glass transition temperature of -50°C or lower.
  • the styrene-butadiene rubber (A) has a glass transition temperature of -50°C or lower, preferably -55°C or lower, and preferably higher than -90°C. If the glass transition temperature of the styrene-butadiene rubber (A) is -50°C or lower, the fuel economy and wear resistance of the tire can be sufficiently improved. In addition, styrene-butadiene rubber with a glass transition temperature higher than -90°C is easy to synthesize.
  • the glass transition temperatures of the styrene-butadiene rubber (A) and the styrene-butadiene rubber (B) described below can be measured, for example, as follows. Using each styrene-butadiene rubber as a sample, a DSC curve is recorded using a TA Instruments DSC250 while heating from -100°C at 20°C/min under a helium flow of 50 mL/min, and the peak top (inflection point) of the DSC differential curve is taken as the glass transition temperature.
  • the content ratio of the styrene-butadiene rubber (A) in the rubber component is preferably 15% by mass or more and less than 85% by mass, more preferably 20 to 85% by mass, more preferably 30 to 80% by mass, and even more preferably 40 to 80% by mass.
  • the content ratio of the styrene-butadiene rubber (A) in the rubber component is 15% by mass or more and less than 85% by mass, the fuel economy performance and wet grip performance of the tire can be further improved.
  • the styrene-butadiene rubber (A) preferably has a bound styrene amount of less than 15% by mass.
  • the bound styrene amount of the styrene-butadiene rubber (A) means the ratio of styrene units contained in the styrene-butadiene rubber.
  • the bound styrene amount is less than 15% by mass, the glass transition temperature is likely to be low.
  • the bound styrene amount is more preferably 14% by mass or less, more preferably 13% by mass or less, and even more preferably 12% by mass or less.
  • the bound styrene amount is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 8% by mass or more.
  • the amount of bound styrene in the styrene-butadiene rubber (A) can be adjusted by the amount of monomers used in the polymerization of the styrene-butadiene rubber, the degree of polymerization, and the like.
  • the styrene-butadiene rubber (A) is modified with a modifier having at least one atom of nitrogen, silicon, and tin. From the viewpoint of achieving a higher level of fuel economy, wear resistance, and wet grip performance of the tire, it is preferable that the rubber is modified with a modifier having a nitrogen atom and a silicon atom, and it is more preferable that the rubber is modified with a modifier having a functional group containing a nitrogen atom and an alkoxy group.
  • the styrene-butadiene rubber (A) is modified with a modifier having a nitrogen atom and a silicon atom, the balance between the wet grip performance, fuel economy, and wear resistance of the tire is further improved, and in particular, the fuel economy and wear resistance can be further improved.
  • the styrene-butadiene rubber (A) is modified with a modifier having a functional group containing a nitrogen atom and an alkoxy group, the balance between the wet grip performance, fuel economy, and wear resistance of the tire is further improved, and in particular, the fuel economy and wear resistance can be further improved.
  • the modifying agent having a functional group containing a nitrogen atom and an alkoxy group is a general term for modifying agents having at least one functional group containing a nitrogen atom and at least one alkoxy group.
  • the functional group containing a nitrogen atom is preferably selected from the following: The monovalent hydrocarbon group having 1 to 30 carbon atoms and containing a straight-chain, branched, alicyclic or aromatic ring, and having a functional group selected from the group consisting of a primary amino group, a primary amino group protected with a hydrolyzable protecting group, an onium salt residue of a primary amine, an isocyanate group, a thioisocyanate group, an imine group, an imine residue, an amide group, a secondary amino group protected with a hydrolyzable protecting group, a cyclic secondary amino group, an onium salt residue of a cyclic secondary amine, a non-cyclic secondary amino group, an onium salt residue of a non-cyclic secondary amine
  • the styrene-butadiene rubber (A) is preferably modified with an aminoalkoxysilane compound, and from the viewpoint of having a high affinity for fillers such as silica, it is even more preferable that the terminals are modified with an aminoalkoxysilane compound.
  • the terminals of the styrene-butadiene rubber are modified with an aminoalkoxysilane compound, the interaction between the styrene-butadiene rubber (A) and the filler (particularly silica) becomes particularly strong.
  • the modified site of the styrene-butadiene rubber (A) may be the molecular terminal as described above, but may also be the main chain.
  • the styrene-butadiene rubber (A) having a modified molecular end can be produced, for example, by reacting various modifiers with the ends of a styrene-butadiene copolymer having active ends according to the methods described in WO 2003/046020 and JP 2007-217562 A.
  • the styrene-butadiene rubber (A) having a modified molecular end can be produced by reacting an aminoalkoxysilane compound with an end of a styrene-butadiene copolymer having an active end with a cis-1,4 bond content of 75% or more, and then reacting the resulting mixture with a carboxylic acid partial ester of a polyhydric alcohol for stabilization, according to the methods described in WO 2003/046020 and JP 2007-217562 A.
  • the carboxylic acid partial ester of a polyhydric alcohol means an ester of a polyhydric alcohol and a carboxylic acid, which has one or more hydroxyl groups. Specifically, an ester of a sugar or modified sugar having 4 or more carbon atoms and a fatty acid is preferably used.
  • this ester include (1) a fatty acid partial ester of a polyhydric alcohol, in particular a partial ester (which may be a monoester, diester, or triester) of a saturated higher fatty acid or an unsaturated higher fatty acid having 10 to 20 carbon atoms and a polyhydric alcohol, and (2) an ester compound in which 1 to 3 partial esters of a polycarboxylic acid and a higher alcohol are bonded to a polyhydric alcohol.
  • the polyhydric alcohol used as a raw material for the partial ester is preferably a saccharide having 5 or 6 carbon atoms and at least three hydroxyl groups (which may or may not be hydrogenated), glycol, polyhydroxy compound, etc.
  • the raw material fatty acid is preferably a saturated or unsaturated fatty acid having 10 to 20 carbon atoms, such as stearic acid, lauric acid, or palmitic acid.
  • fatty acid partial esters of polyhydric alcohols sorbitan fatty acid esters are preferred, and specific examples thereof include sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, and sorbitan trioleate.
  • the aminoalkoxysilane compound is not particularly limited, but is preferably an aminoalkoxysilane compound represented by the following general formula (i).
  • aminoalkoxysilane compound an aminoalkoxysilane compound represented by the following general formula (ii) is also preferred.
  • a 1 is at least one functional group selected from a saturated cyclic tertiary amine compound residue, an unsaturated cyclic tertiary amine compound residue, a ketimine residue, a nitrile group, a (thio)isocyanate group, an isocyanuric acid trihydrocarbyl ester group, a nitrile group, a pyridine group, a (thio)ketone group, an amide group, and a primary or secondary amino group having a hydrolyzable group.
  • a 1 When n4 is 2 or more, A 1 may be the same or different, and A 1 may be a divalent group that bonds with Si to form a cyclic structure.
  • R 21 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and when n1 is 2 or more, R 21 may be the same or different.
  • R 22 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, either of which may contain a nitrogen atom and/or a silicon atom.
  • R 22 When n2 is 2 or greater, R 22 may be the same or different from each other, or may be joined together to form a ring.
  • R 23 represents a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or a halogen atom, and when n3 is 2 or greater, may be the same or different.
  • R 24 is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and when n4 is 2 or greater, R 24 may be the same or different.
  • the hydrolyzable group in the hydrolyzable group-containing primary or secondary amino group a trimethylsilyl group or a tert-butyldimethylsilyl group is preferred, and a trimethylsilyl group is particularly preferred.
  • aminoalkoxysilane compound represented by the above general formula (ii) is preferably an aminoalkoxysilane compound represented by the following general formula (iii).
  • p1+p2+p3 2 (wherein p2 is an integer of 1 or 2, and p1 and p3 are integers of 0 or 1).
  • A2 is NRa (Ra is a monovalent hydrocarbon group, a hydrolyzable group, or a nitrogen-containing organic group).
  • R 25 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • R 26 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or a nitrogen-containing organic group, any of which may contain a nitrogen atom and/or a silicon atom.
  • R 26 may be the same or different from each other, or may be joined together to form a ring.
  • R 27 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or a halogen atom.
  • R 28 is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • a trimethylsilyl group or a tert-butyldimethylsilyl group is preferred, and a trimethylsilyl group is particularly preferred.
  • aminoalkoxysilane compound represented by the above general formula (ii) is also preferably an aminoalkoxysilane compound represented by the following general formula (iv) or (v).
  • R 31 is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • R 32 and R 33 each independently represent a hydrolyzable group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • R 34 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and when q1 is 2, may be the same or different.
  • R 35 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and when q2 is 2 or greater, R 35 may be the same or different.
  • R 36 is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • R 37 is a dimethylaminomethyl group, a dimethylaminoethyl group, a diethylaminomethyl group, a diethylaminoethyl group, a methylsilyl(methyl)aminomethyl group, a methylsilyl(methyl)aminoethyl group, a methylsilyl(ethyl)aminomethyl group, a methylsilyl(ethyl)aminoethyl group, a dimethylsilylaminomethyl group, a dimethylsilylaminoethyl group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and when r1 is 2 or more, they may be the same or different.
  • R 38 is a hydrocarbyloxy group having 1 to 20 carbon atoms, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and when r2 is 2, they may be the same or different.
  • a specific example of the aminoalkoxysilane compound represented by the general formula (v) is N-(1,3-dimethylbutylidene)-3-triethoxysilyl-1-propaneamine.
  • aminoalkoxysilane compound represented by the above general formula (ii) is also preferably an aminoalkoxysilane compound represented by the following general formula (vi) or (vii).
  • R 40 represents a trimethylsilyl group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • R 41 is a hydrocarbyloxy group having 1 to 20 carbon atoms, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • R 42 is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • TMS represents a trimethylsilyl group (hereinafter the same).
  • R 43 and R 44 each independently represent a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • R 45 is a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, and each R 45 may be the same or different.
  • aminoalkoxysilane compound represented by the above general formula (ii) is also preferably an aminoalkoxysilane compound represented by the following general formula (viii) or the following general formula (ix).
  • s1+s2 is 3 (wherein s1 is an integer of 0 to 2, and s2 is an integer of 1 to 3).
  • R 46 is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • R 47 and R 48 are each independently a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms. Multiple R 47s or R 48s may be the same or different.
  • X is a halogen atom.
  • R 49 is a divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • R 50 and R 51 are each independently a hydrolyzable group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, or R 50 and R 51 combine together to form a divalent organic group.
  • R 52 and R 53 each independently represent a halogen atom, a hydrocarbyloxy group, a monovalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • R 50 and R 51 are preferably a hydrolyzable group, and the hydrolyzable group is preferably a trimethylsilyl group or a tert-butyldimethylsilyl group, and particularly preferably a trimethylsilyl group.
  • aminoalkoxysilane compound represented by the above general formula (ii) is also preferably an aminoalkoxysilane compound represented by the following general formula (x), the following general formula (xi), the following general formula (xii), or the following general formula (xiii).
  • R 54 to R 92 in general formulas (x) to (xiii) may be the same or different and are a monovalent or divalent aliphatic or alicyclic hydrocarbon group having 1 to 20 carbon atoms, or a monovalent or divalent aromatic hydrocarbon group having 6 to 18 carbon atoms.
  • ⁇ and ⁇ are integers of 0 to 5.
  • N1,N1,N7,N7-tetramethyl-4-((trimethoxysilyl)methyl)heptane-1,7-diamine 2-((hexyl-dimethoxysilyl)methyl)-N1,N1,N3,N3-2-pentamethylpropane-1,3-diamine, N1-(3-(dimethylamino)propyl)-N3,N3-dimethyl-N1-(3-(trimethoxysilyl)propyl)propane-1,3-diamine, and 4-(3-(dimethylamino)propyl)-N1,N1,N7,N7-tetramethyl-4-((trimethoxysilyl)methyl)heptane-1,7-diamine are particularly preferred.
  • the method for producing the styrene-butadiene rubber (A) is not particularly limited.
  • the method for producing the styrene-butadiene rubber (A) may include: 1) polymerizing styrene-butadiene rubber in a hydrocarbon solvent in the presence of an organic alkali metal compound to produce an activated polymer having an alkali metal bonded to at least one end; and 2) reacting the activated polymer with a modifier such as the aminoalkoxysilane compound.
  • the step 1) is a step for producing an activated polymer having an alkali metal bonded to at least one end, and can be carried out by polymerizing a styrene-based monomer and a butadiene-based monomer in a hydrocarbon solvent in the presence of an organic alkali metal compound.
  • the hydrocarbon solvent is not particularly limited, but may be, for example, one or more selected from the group consisting of n-pentane, n-hexane, n-heptane, isooctane, cyclohexane, toluene, benzene, and xylene.
  • the organic alkali metal compound may be used in an amount of 0.1 mmol to 1.0 mmol based on 100 g of the total monomer.
  • the organic alkali metal compound is not particularly limited, and for example, one or more compounds selected from the group consisting of methyl lithium, ethyl lithium, propyl lithium, n-butyl lithium, s-butyl lithium, t-butyl lithium, hexyl lithium, n-decyl lithium, t-octyl lithium, phenyl lithium, 1-naphthyl lithium, n-eicosyl lithium, 4-butylphenyl lithium, 4-tolyl lithium, cyclohexyl lithium, 3,5-di-n-heptylcyclohexyl lithium, 4-cyclopentyl lithium, naphthyl sodium, naphthyl potassium, lithium alkoxide, sodium alkoxide, potassium alkoxide, lithium sulfonate, sodium sulfon
  • the polymerization in step 1) may be carried out by further adding a polar additive as necessary, and the polar additive may be added in an amount of 0.001 to 1.0 parts by weight based on 100 parts by weight of the total monomers, specifically, 0.005 to 0.5 parts by weight, more specifically, 0.01 to 0.3 parts by weight based on 100 parts by weight of the total monomers.
  • polar additive for example, one or more selected from the group consisting of tetrahydrofuran, ditetrahydrofurylpropane, diethyl ether, cycloamyl ether, dipropyl ether, ethylene dimethyl ether, ethylene dimethyl ether, diethyl glycol, dimethyl ether, tert-butoxyethoxyethane, bis(3-dimethylaminoethyl)ether, (dimethylaminoethyl)ethyl ether, trimethylamine, triethylamine, tripropylamine, and tetramethylethylenediamine can be used.
  • the polymerization in the step 1) can be carried out via adiabatic polymerization or isothermal polymerization.
  • the adiabatic polymerization refers to a polymerization method including a step of polymerizing the organic alkali metal compound by self-reaction heat without adding any heat after the organic alkali metal compound is added
  • the isothermal polymerization refers to a polymerization method in which the temperature of the polymer is kept constant by adding or removing heat after the organic alkali metal compound is added.
  • the polymerization may be carried out in a temperature range of 20°C to 200°C, specifically 0°C to 150°C, more specifically 10°C to 120°C.
  • the step 2) is a modification reaction step in which the activated polymer is reacted with a modifier such as the aminoalkoxysilane compound described above to produce styrene-butadiene rubber (A).
  • a modifier such as the aminoalkoxysilane compound described above to produce styrene-butadiene rubber (A).
  • the modifier may be the same as that described above, and may be used in an amount of 0.1 to 2.0 moles per mole of the organic alkali metal compound.
  • the reaction in step 2) is a modification reaction for introducing a functional group into the polymer, and each reaction can be carried out at a temperature range of 0° C. to 90° C. for 1 minute to 5 hours.
  • the above-mentioned manufacturing method may further include, after step 2), one or more steps of recovering the solvent and unreacted monomer and drying, if necessary.
  • the content ratio of the styrene-butadiene rubber (A) modified by a modifying agent such as the aminoalkoxysilane compound in the rubber component is not particularly limited, but is preferably 15% by mass or more, more preferably 20% by mass or more, preferably less than 85% by mass, more preferably 60% by mass or less, and even more preferably 50% by mass or less.
  • a modifying agent such as the aminoalkoxysilane compound in the rubber component
  • the content ratio of the styrene-butadiene rubber (A) in the rubber component is 60% by mass or less, the styrene-butadiene rubber (B) described below can be sufficiently contained, and the wet grip performance of the tire can be well maintained.
  • the rubber component further contains, in addition to the styrene-butadiene rubber (A), an unmodified styrene-butadiene rubber (B) having a glass transition temperature at least 30° C. higher than that of the styrene-butadiene rubber (A).
  • the glass transition temperature of the styrene-butadiene rubber (B) must be at least 30°C higher than the glass transition temperature of the styrene-butadiene rubber (A), and is preferably at least 35°C higher.
  • the content ratio of the styrene-butadiene rubber (B) in the rubber component is not particularly limited, but is preferably 15% by mass or more, more preferably 20% by mass or more, and also preferably less than 85% by mass, more preferably 80% by mass or less.
  • the content ratio of the styrene-butadiene rubber (B) in the rubber component is 15% by mass or more, the wet grip performance of the tire can be further improved.
  • the content ratio of the styrene-butadiene rubber (B) in the rubber component is less than 85% by mass, the fuel economy performance and wear resistance performance of the tire can be well maintained. Therefore, by having the rubber component contain 15% by mass or more and less than 85% by mass of the styrene-butadiene rubber (B), the wet grip performance can be further improved while maintaining the fuel economy performance and wear resistance performance well.
  • the content ratio of the styrene-butadiene rubber (B) is greater than the content ratio of the styrene-butadiene rubber (A) [content ratio of styrene-butadiene rubber (B)/content ratio of styrene-butadiene rubber (A)>1].
  • the rubber component may contain a rubber (other rubber) different from the styrene-butadiene rubber (A) and the styrene-butadiene rubber (B) as a rubber component for the purpose of improving the fuel efficiency performance, wear resistance, etc. of the tire.
  • the other rubbers can be appropriately selected depending on the required performance.
  • diene rubbers such as natural rubber (NR), butadiene rubber (BR), synthetic isoprene rubber (IR), ethylene-propylene copolymer rubber, and non-diene rubbers such as butyl rubber can be used.
  • the rubber component consists of only the styrene-butadiene rubber (A) and the styrene-butadiene rubber (B).
  • the amount of the filler is not particularly limited, but is preferably 20 parts by mass or more, more preferably 30 parts by mass or more, and even more preferably 40 parts by mass or more, and is preferably 150 parts by mass or less, more preferably 140 parts by mass or less, and even more preferably 120 parts by mass or less, per 100 parts by mass of the rubber component.
  • wet grip performance, fuel efficiency, and abrasion resistance can be achieved at a higher level.
  • the filler amount is 20 parts by mass or more, sufficient wet grip performance, fuel efficiency, and abrasion resistance can be obtained, and when the filler amount is 150 parts by mass or less, deterioration of low heat generation performance and processability can be suppressed.
  • the silica contained in the filler is not particularly limited, and can be appropriately selected according to the required performance.
  • wet silica hydrated silicic acid
  • dry silica anhydrous silicic acid
  • calcium silicate aluminum silicate, etc.
  • wet silica is preferred.
  • These silicas can be used alone or in combination of two or more kinds.
  • the wet silica may be precipitated silica, which is obtained by growing primary silica particles in a reaction solution at a relatively high temperature and in a neutral to alkaline pH range in the early stages of production, and then agglomerating the primary particles by controlling the reaction solution to an acidic pH range.
  • silica derived from silicic acid plants is also preferred from the viewpoint of reducing the environmental load.
  • the silicic acid plants are present, for example, in mosses, ferns, horsetails, Cucurbitaceae, Urticaceae, and Gramineae plants.
  • Gramineae plants are preferred.
  • Examples of the Gramineae plants include rice, bamboo, and sugarcane, and among these, rice is preferred. Since rice is widely cultivated for food, it can be procured locally in a wide area, and since rice husks are generated in large quantities as industrial waste, it is easy to secure the amount.
  • silica derived from rice husks (hereinafter also referred to as "rice husk silica”) is particularly preferred as silica.
  • rice husk silica By using the rice husk silica, rice husks that become industrial waste can be effectively utilized, and since the raw material can be procured locally near the tire manufacturing plant, the energy and cost of transportation and storage can be reduced, which is environmentally preferable from various viewpoints.
  • the rice husk charcoal thus obtained is pulverized using a known pulverizer (e.g., a ball mill), and then sorted and classified into a predetermined particle size range to obtain rice husk charcoal powder.
  • a known pulverizer e.g., a ball mill
  • the precipitated silica derived from rice husks can be produced by the method described in JP 2019-38728 A, etc.
  • the silica preferably has a CTAB (cetyltrimethylammonium bromide) specific surface area of 50 m 2 /g to 350 m 2 /g.
  • CTAB cetyltrimethylammonium bromide
  • the silica preferably has a nitrogen adsorption specific surface area (BET method) of 80 m 2 /g or more and less than 330 m 2 /g.
  • BET method nitrogen adsorption specific surface area
  • the tread rubber layer can be sufficiently reinforced, and the fuel efficiency performance of the tire can be further improved.
  • the nitrogen adsorption specific surface area (BET method) of silica is less than 330 m 2 /g, the elastic modulus of the tread rubber layer does not become too high, and the wet grip performance of the tire is further improved.
  • the nitrogen adsorption specific surface area (BET method) of the silica is preferably 130 m 2 /g or more, preferably 150 m 2 /g or more, preferably 170 m 2 /g or more, preferably 180 m 2 /g or more, preferably 190 m 2 /g or more, and more preferably 195 m 2 /g or more.
  • the nitrogen adsorption specific surface area (BET method) of the silica is preferably 300 m 2 /g or less, more preferably 280 m 2 /g or less, and even more preferably 270 m 2 /g or less.
  • the amount of the silica is preferably 20 parts by mass or more and less than 100 parts by mass per 100 parts by mass of the rubber component.
  • the silica content is 20 parts by mass or more and less than 100 parts by mass with respect to 100 parts by mass of the rubber component, deterioration of low heat generation and processability can be suppressed while sufficient wet grip performance, fuel efficiency and abrasion resistance can be obtained.
  • the content of the silica is more preferably 40 parts by mass or more, more preferably 50 parts by mass or more, even more preferably 62 parts by mass or more, even more preferably 65 parts by mass or more, and particularly preferably 68 parts by mass or more, relative to 100 parts by mass of the rubber component.
  • the content of the silica is more preferably 90 parts by mass or less, even more preferably 85 parts by mass or less, and particularly preferably 82 parts by mass or less, relative to 100 parts by mass of the rubber component.
  • the filler preferably further contains carbon black, which can reinforce the rubber composition and improve the abrasion resistance of the rubber composition.
  • the carbon black is not particularly limited, and examples thereof include GPF, FEF, HAF, ISAF, and SAF grade carbon black. These carbon blacks may be used alone or in combination of two or more. The carbon black may also be recycled carbon black.
  • waste carbon black refers to carbon black recovered from raw materials that are waste materials that have been recycled.
  • waste materials that have been recycled include rubber products (especially vulcanized rubber products) that contain carbon black, such as used rubber and used tires, and waste oil.
  • Recycled carbon black is different from carbon black that is produced directly from raw materials such as hydrocarbons, such as petroleum and natural gas, i.e., carbon black that is not recycled. Note that “used” here does not only include carbon black that has actually been used and then discarded, but also carbon black that has been produced but discarded without actually being used.
  • the content of silica in the total amount of the silica and the carbon black is preferably 80% by mass or more and less than 100% by mass, more preferably 85% by mass or more and less than 100% by mass, and even more preferably 90% by mass or more and less than 100% by mass.
  • the content of silica in the total amount of the silica and the carbon black is 80% by mass or more, it is possible to suppress a decrease in fuel efficiency performance due to an increase in carbon black, and when it is less than 100% by mass, it is possible to reliably ensure the reinforcing effect of carbon black.
  • the filler further contains carbon black and the content of silica in the total amount of the silica and the carbon black is 80% by mass or more and less than 100% by mass, it is possible to reliably ensure the reinforcing effect of carbon black while suppressing a decrease in fuel efficiency performance.
  • nM ⁇ xSiO y ⁇ zH 2 O... (I) is at least one selected from the group consisting of metals selected from the group consisting of Al, Mg, Ti, Ca, and Zr, oxides or hydroxides of these metals, and hydrates thereof, and carbonates of these metals; n, x, y, and z are integers of 1 to 5, integers of 0 to 10, integers of 2 to 5, and integers of 0 to 10, respectively.
  • the filler contains other inorganic compounds, the content thereof is preferably about 5 to 30 parts by mass based on 100 parts by mass of the rubber component.
  • Examples of the inorganic compound of the above formula (I) include alumina (Al 2 O 3 ) such as ⁇ -alumina and ⁇ -alumina; alumina monohydrate (Al 2 O 3 .H 2 O) such as boehmite and diaspore; aluminum hydroxide [Al(OH) 3 ] such as gibbsite and bayerite; aluminum carbonate [Al 2 (CO 3 ) 3 ], magnesium hydroxide [Mg(OH) 2 ], magnesium oxide (MgO), magnesium carbonate (MgCO 3 ), talc (3MgO.4SiO 2.H 2 O), attapulgite (5MgO.8SiO 2.9H 2 O), titanium white (TiO 2 ), titanium black (TiO 2n-1 ), calcium oxide (CaO), calcium hydroxide [Ca(OH) 2 ], aluminum magnesium oxide (MgO.Al 2 O 3 ), clay (Al 2 O 3.2SiO 2 ), kaolin (Al 2 O 3.2
  • the rubber composition for the tread rubber layer further contains a silane coupling agent in addition to the rubber component and the filler.
  • a silane coupling agent in addition to the rubber component and the filler.
  • the inclusion of the silane coupling agent enhances the dispersibility of the silica contained as a filler, and contributes to achieving both wet grip performance, fuel efficiency and abrasion resistance.
  • the silane coupling agent contains at least a silane coupling agent (A) having a thiol group and a silane coupling agent (B) having a sulfide bond.
  • the silane coupling agent (A) having thiol group has a high effect of enhancing the dispersibility of silica described above, but when the content is large, it may cause discoloration such as black luster on tire with aging.
  • the silane coupling agent (B) having sulfide bond as the silane coupling agent and adjusting the content of these silane coupling agents it is possible to suppress discoloration such as black luster while achieving both wet grip performance of tire, low fuel consumption performance and wear resistance (excellent discoloration resistance).
  • the total content of the silane coupling agent (A) and the silane coupling agent (B) is more than 1 part by mass and not more than 15 parts by mass with respect to 100 parts by mass of the silica.
  • the total content of the silane coupling agent is more than 1 part by mass with respect to 100 parts by mass of the silica, so that the wet grip performance of the tire can be sufficiently achieved, as well as the low fuel consumption performance and the wear resistance performance, and the total content of the silane coupling agent is not more than 15 parts by mass with respect to 100 parts by mass of the silica, so that the discoloration resistance can be sufficiently ensured.
  • the total content of the silane coupling agent (A) and the silane coupling agent (B) is preferably 2 to 14 parts by mass, more preferably 3 to 13 parts by mass, and even more preferably 5 to 12 parts by mass, relative to 100 parts by mass of the silica.
  • the content of the silane coupling agent (A) is 1 to 10 parts by mass relative to 100 parts by mass of the silica.
  • the content of the silane coupling agent (A) is 1 part by mass or more relative to 100 parts by mass of the silica, the tire wet grip performance, fuel efficiency performance and wear resistance can be sufficiently achieved, and when the content of the silane coupling agent (A) is 10 parts by mass or less relative to 100 parts by mass of the silica, discoloration resistance can be sufficiently ensured.
  • the content of the silane coupling agent (A) is preferably 2 to 9.5 parts by mass, more preferably 3 to 9 parts by mass relative to 100 parts by mass of the silica.
  • the content of the silane coupling agent (B) is appropriately selected within a range in which the content of the silane coupling agent (A) is within a range of 1 to 10 parts by mass relative to 100 parts by mass of the silica, and the total content of the silane coupling agent (A) and the silane coupling agent (B) is 15 parts by mass or less relative to 100 parts by mass of the silica.
  • the content of the silane coupling agent (B) is preferably 0.5 to 9.5 parts by mass, more preferably 1 to 9 parts by mass relative to 100 parts by mass of the silica.
  • the silane coupling agent (A) is not particularly limited as long as it has a thiol group (-SH).
  • examples of the silane coupling agent (A) having a thiol group include 3-(trimethoxysilyl)-1-propanethiol, 3-(triethoxysilyl)-1-propanethiol, 3-(methyldimethoxysilyl)-1-propanethiol, 2-(trimethoxysilyl)-1-ethanethiol, 2-(triethoxysilyl)-1-ethanethiol, 2-(methyldimethoxysilyl)-1-ethanethiol, (trimethoxysilyl)methanethiol, (triethoxysilyl)methanethiol, (methyldimethoxysilyl)methanethiol, 3-[ethoxybis(3,6,9,12,15-pentaoxaoctacosan-1-yloxy)silyl]
  • the silane coupling agent (B) is not particularly limited as long as it has a sulfide bond (-S-).
  • a plurality of sulfide bonds may be connected to form a polysulfide bond [-(S) n -, where n is a natural number of 2 or more], but this does not include -SH, in which hydrogen is directly bonded to sulfur (i.e., the above-mentioned thiol group).
  • silane coupling agent (B) having a sulfide bond examples include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, 3-triethoxysilylpropyl-N,N-dimethyl thiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazolyl tetrasulfide, 3-trie
  • bioethanol can also be used as a raw material for the silane coupling agent.
  • Bioethanol is produced mainly using sugars and/or cellulose as biological resources, and other biological resources such as proteins, lipids, and amino acids cannot be effectively utilized.
  • sugars compete with food, and excessive use of cellulose leads to deforestation. Therefore, it is preferable to use multiple types of monomer components derived from biological resources as the monomer components derived from the biological resources, or to use a combination of monomer components derived from biological resources, monomer components derived from renewable resources, and monomer components derived from fossil resources, depending on the supply situation of various biological resources, the supply situation of renewable resources, the supply situation of fossil resources, and market demands (for example, demand for biomass resources as food).
  • This makes it possible to effectively utilize a wide range of biological resources and renewable resources such as sugars, proteins, and lipids without relying on a single type of biological resource, and also to take the environment into consideration depending on the situation at the time of production.
  • the C5 resin may be an aliphatic petroleum resin obtained by (co)polymerizing a C5 fraction obtained by thermal cracking of naphtha in the petrochemical industry.
  • the C5 fraction usually contains olefinic hydrocarbons such as 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene, and diolefinic hydrocarbons such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, and 3-methyl-1,2-butadiene, etc.
  • olefinic hydrocarbons such as 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene
  • diolefinic hydrocarbons such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, and 3-methyl-1,2-butadiene, etc.
  • the C5 - C9 resin refers to a C5 - C9 synthetic petroleum resin.
  • the C5 - C9 resin include solid polymers obtained by polymerizing a petroleum-derived C5 - C11 fraction using a Friedel-Crafts catalyst such as AlCl3 or BF3 . More specifically, examples of the C5-C9 resin include copolymers mainly composed of styrene, vinyltoluene, ⁇ -methylstyrene, indene, etc.
  • a resin having a small amount of C9 or more components is preferred from the viewpoint of compatibility with the rubber component.
  • "having a small amount of C9 or more components” means that the amount of C9 or more components in the total amount of the resin is less than 50 mass%, preferably 40 mass% or less.
  • Commercially available C5 - C9 resins can be used.
  • the terpene resin is a solid resin obtained by blending turpentine, which is obtained at the same time as rosin is obtained from pine trees, or a polymerization component separated from this, and polymerizing it using a Friedel-Crafts catalyst, and examples of this include ⁇ -pinene resin and ⁇ -pinene resin.
  • a representative example of a terpene-aromatic compound resin is terpene-phenol resin. This terpene-phenol resin can be obtained by reacting terpenes with various phenols using a Friedel-Crafts catalyst, or by further condensing with formalin.
  • terpenes used as raw materials there are no particular restrictions on the terpenes used as raw materials, and monoterpene hydrocarbons such as ⁇ -pinene and limonene are preferred, and those containing ⁇ -pinene are more preferred, with ⁇ -pinene being particularly preferred. Styrene, etc. may also be included in the skeleton.
  • the dicyclopentadiene-based resin refers to a resin obtained by polymerizing dicyclopentadiene using a Friedel-Crafts type catalyst such as AlCl3 or BF3 .
  • the resin is preferably at least partially hydrogenated, i.e., a hydrogenated resin, which can improve the hysteresis loss (tan ⁇ ) in the low temperature range by at least partially hydrogenating the resin, thereby further improving the wet grip performance of the tire.
  • the at least partially hydrogenated resin means a resin obtained by reducing and hydrogenating a resin.
  • the resin that is the raw material for the hydrogenated resin may include, for example, a resin obtained by copolymerizing a C5 fraction with dicyclopentadiene (DCPD) ( C5 -DCPD-based resin).
  • DCPD dicyclopentadiene
  • the C5- DCPD-based resin is considered to be included in the dicyclopentadiene-based resin.
  • the C5 - DCPD-based resin is considered to be included in the C5- based resin.
  • the resin preferably has a softening point higher than 110° C. and a weight average molecular weight in terms of polystyrene of 200 to 1600 g/mol.
  • a rubber composition containing such a resin to a tread rubber layer of a tire, the wear resistance of the tire can be further improved.
  • the softening point of the resin is higher than 110° C., the tread rubber layer of the tire can be sufficiently reinforced, and the wear resistance can be further improved.
  • the softening point of the resin is preferably 116° C. or higher, more preferably 120° C. or higher, more preferably 123° C. or higher, and even more preferably 127° C. or higher.
  • the softening point of the resin is preferably 160° C. or lower, more preferably 150° C. or lower, more preferably 145° C. or lower, more preferably 141° C. or lower, and even more preferably 136° C. or lower.
  • the polystyrene-equivalent weight average molecular weight of the resin can be calculated by measuring the average molecular weight by gel permeation chromatography (GPC) under the following conditions, for example. Column temperature: 40°C ⁇ Injection volume: 50 ⁇ L Carrier and flow rate: Tetrahydrofuran 0.6 mL/min Sample preparation: About 2.5 mg of resin was dissolved in 10 mL of tetrahydrofuran.
  • the softening point of the resin can be measured, for example, in accordance with JIS-K2207-1996 (ring and ball method).
  • the polystyrene-equivalent weight average molecular weight of the resin is preferably 500 g/mol or more, more preferably 550 g/mol or more, more preferably 600 g/mol or more, more preferably 650 g/mol or more, and even more preferably 700 g/mol or more.
  • the polystyrene-equivalent weight average molecular weight of the resin is preferably 1350 g/mol or less, more preferably 1330 g/mol or less, more preferably 1300 g/mol or less, more preferably 1200 g/mol or less, more preferably 1100 g/mol or less, more preferably 1000 g/mol or less, and even more preferably 950 g/mol or less.
  • the content of the resin is preferably 1 to 50 parts by mass per 100 parts by mass of the rubber component.
  • the content of the resin in the rubber composition is 1 part by mass or more per 100 parts by mass of the rubber component, the effect of the resin is fully expressed, and when it is 50 parts by mass or less, the resin is less likely to precipitate from the tire and the effect of the resin can be fully expressed. Therefore, when the content of the resin is 1 to 50 parts by mass per 100 parts by mass of the rubber component, the effect of the resin can be fully expressed while suppressing the resin from precipitating from the tire.
  • the content of the resin in the rubber composition is preferably 5 parts by mass or more per 100 parts by mass of the rubber component, more preferably 7 parts by mass or more, and even more preferably 9 parts by mass or more.
  • the content of the resin in the rubber composition is more preferably 45 parts by mass or less per 100 parts by mass of the rubber component, more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less.
  • the rubber composition for the tread rubber layer may contain, in addition to the above-mentioned rubber components, fillers, silane coupling agents, and resins, various components commonly used in the rubber industry, such as antioxidants, waxes, softeners, processing aids, stearic acid, zinc oxide (zinc oxide), vulcanization accelerators, vulcanizing agents, etc., as necessary, appropriately selected within a range that does not impair the object of the present invention. Commercially available products can be suitably used as these compounding agents.
  • the antioxidants include N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6C), 2,2,4-trimethyl-1,2-dihydroquinoline polymer (TMDQ), 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (AW), N,N'-diphenyl-p-phenylenediamine (DPPD), etc.
  • TMDQ 2,2,4-trimethyl-1,2-dihydroquinoline polymer
  • AW 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline
  • DPPD N,N'-diphenyl-p-phenylenediamine
  • wax examples include paraffin wax and microcrystalline wax.
  • amount of the wax is preferably in the range of 0.1 to 5 parts by mass, and more preferably 1 to 4 parts by mass, per 100 parts by mass of the rubber component.
  • the amount of zinc oxide (zinc white) is not particularly limited, and is preferably 8 parts by mass or less, more preferably 6 parts by mass or less, and even more preferably less than 4 parts by mass, per 100 parts by mass of the rubber component. If the amount of zinc white is too high (more than 8 parts by mass), it may not disperse and the fracture properties may deteriorate.
  • the vulcanization accelerator may be a sulfenamide-based vulcanization accelerator, a guanidine-based vulcanization accelerator, a thiazole-based vulcanization accelerator, a thiuram-based vulcanization accelerator, a dithiocarbamate-based vulcanization accelerator, or the like. These vulcanization accelerators may be used alone or in combination of two or more. There are no particular limitations on the content of the vulcanization accelerator, and the content is preferably in the range of 0.1 to 5 parts by mass, and more preferably in the range of 0.2 to 4 parts by mass, per 100 parts by mass of the rubber component.
  • the vulcanizing agent may be sulfur.
  • the content of the vulcanizing agent is preferably in the range of 0.1 to 10 parts by mass, more preferably 1 to 4 parts by mass, in terms of sulfur content per 100 parts by mass of the rubber component.
  • the method for producing the rubber composition for the tread rubber layer is not particularly limited.
  • the rubber composition can be produced by blending various components appropriately selected as necessary with the above-mentioned rubber components, filler, and silane coupling agent, kneading, heating, extruding, etc.
  • the obtained rubber composition can be vulcanized to produce a vulcanized rubber.
  • kneading there are no particular limitations on the conditions for the kneading, and the input volume of the kneading device, the rotation speed of the rotor, the ram pressure, etc., as well as the conditions for the kneading temperature, kneading time, type of kneading device, etc., can be appropriately selected according to the purpose.
  • kneading devices include Banbury mixers, intermixes, kneaders, rolls, etc., which are typically used for kneading rubber compositions.
  • heat-in process temperature heat-in process time
  • heat-in process equipment heat-in process equipment
  • other conditions can be appropriately selected depending on the purpose.
  • the heat-in process equipment include a heat-in process roll machine that is typically used for heat-in process of rubber compositions.
  • extrusion conditions there are no particular limitations on the extrusion conditions, and various conditions such as extrusion time, extrusion speed, extrusion equipment, and extrusion temperature can be appropriately selected depending on the purpose.
  • extrusion equipment include extruders that are typically used for extruding rubber compositions.
  • the extrusion temperature can be appropriately determined.
  • Typical vulcanization equipment includes a mold vulcanizer that uses a mold used to vulcanize rubber compositions.
  • the vulcanization temperature is, for example, about 100 to 190°C.
  • the belt layer includes a cord having a structure formed by twisting filaments, and the cord of the belt layer is further coated with a belt coating rubber.
  • the filament constituting the cord of the belt layer has a diameter of X (mm) and a tensile strength of Y (MPa) that satisfies the following formula: 4000-2000X ⁇ Y ⁇ 4500-2000X
  • the hardness of the surface layer of the filament constituting the cord of the belt layer is preferably 90 to 110% of the hardness of the inner layer, and 100% is particularly preferable.
  • the hardness can be measured, for example, by Vickers hardness.
  • the surface layer of the filament means the layer from the outermost surface to a depth of 0.01 mm, and the area inside this refers to the inner layer of the filament.
  • the hardness can be measured in a region 0.005 mm deep from the outermost surface for the surface layer, and 0.04 mm deep for the inner layer.
  • the method for producing the filaments constituting the cords of the belt layer is not particularly limited.
  • the filaments may be obtained, for example, by refining iron ore and drawing wire, by refining scrap iron and drawing wire, or by recycling steel extracted from tires.
  • a plurality of cords are arranged in parallel.
  • Such cords are generally steel cords. There is no particular limitation on the structure of such cords.
  • the cord can have a 1xN open structure in which the filaments are twisted together with a gap between them and do not touch each other.
  • a cord with an open structure has better fatigue resistance than a cord in which the filaments are twisted together while touching each other.
  • a cord with a 1xN open structure can be formed by sandwiching unvulcanized rubber between the filaments and twisting them together, or by covering the surfaces of the filaments with unvulcanized rubber and then twisting them together.
  • the cord density in the belt layer is preferably 60 cords/dm or more and 95 cords/dm or less. In this case, the tire can effectively achieve both cut resistance and low fuel consumption performance.
  • the diameter of the cord of the belt layer is preferably 0.5 mm or more and 1.0 mm or less. In this case, the tire can effectively achieve both cut resistance and low fuel consumption performance.
  • the coating rubber is not particularly limited as long as it is a general rubber composition capable of coating steel cords.
  • rubber components include diene rubbers, and in particular, natural rubber or isoprene rubber is preferred.
  • the natural rubber may be modified. In the case of modified natural rubber, it is preferable that the modified natural rubber has a nitrogen content of, for example, 0.1 to 0.3% by mass. It is also preferable that the modified natural rubber has had proteins removed by a centrifugation process, enzyme treatment, or urea treatment. It is also preferable that the phosphorus content of the modified natural rubber is more than 200 ppm and 900 ppm or less.
  • the coating rubber may contain a filler such as carbon black as long as it does not affect the performance of the coating rubber, such as adhesion and durability.
  • the tire of the present embodiment may be obtained by molding and then vulcanizing an unvulcanized rubber composition or an unvulcanized treat (a cord-rubber composite in which a cord is coated with rubber) or the like, depending on the type of tire to be applied, or may be obtained by molding and then vulcanizing a semi-vulcanized rubber that has been subjected to a pre-vulcanization process or the like instead of an unvulcanized rubber composition.
  • the components of the tire of the present embodiment other than the tread rubber layer and the belt layer are not particularly limited, and known components can be used.
  • the tire of this embodiment is preferably a pneumatic tire, and the gas filled into the pneumatic tire may be normal air or air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, or helium.
  • Tg glass transition temperature
  • bound styrene content of the styrene-butadiene rubber were measured by the following method.
  • Tg Glass transition temperature
  • the synthesized styrene-butadiene rubber was used as a sample, and a DSC curve was recorded using a TA Instruments DSC250 while heating from ⁇ 100° C. at 20° C./min under a helium flow of 50 mL/min. The peak top (inflection point) of the DSC differential curve was determined as the glass transition temperature.
  • Bound styrene content The synthesized styrene-butadiene rubber was used as a sample, and 100 mg of the sample was dissolved in chloroform to prepare a measurement sample. The bound styrene content (mass%) relative to 100 mass% of the sample was measured based on the amount of absorption of ultraviolet light by the phenyl group of styrene at a wavelength (near 254 nm). A spectrophotometer "UV-2450" manufactured by Shimadzu Corporation was used as the measurement device.
  • a belt layer is prepared by covering with a coating rubber a cord having a structure and diameter shown in Table 1.
  • the placement density of the cord in each belt layer is as shown in Table 1.
  • the strength of the obtained belt layer and the strength of the cord alone are measured by the following method.
  • the strength of the belt is calculated from the strength of the individual cord used and the density of the cord in the belt layer.
  • the evaluation result is expressed as an index, with the strength of the belt using the conventional cord being set at 100. The higher the index value, the higher the strength of the belt.
  • Rubber compositions of the examples and comparative examples were prepared by blending and kneading each component according to the formulation shown in Tables 2 and 3.
  • the blended amounts of the rubber components shown in Tables 2 and 3 are shown as values including the amount of oil extension.
  • the blended amount of each component is shown as the amount (parts by mass) per 100 parts by mass of the rubber component.
  • the obtained rubber compositions of the Examples and Comparative Examples were vulcanized to obtain vulcanized rubber test pieces.
  • Abrasion resistance performance index ⁇ (amount of wear of test piece of Comparative Example 1)/(amount of wear of each test piece) ⁇ 100
  • the cut resistance index is the sum of the improvement range of the storage modulus (E') index, the improvement range of the belt strength index, and 100, and here, when each index is lower than the standard, the improvement range is a negative value.
  • Tg modified SBR SBR obtained using butyl lithium as an initiator, with a glass transition temperature (Tg) of -38 ° C., and a styrene-butadiene rubber modified with N-(1,3-dimethylbutylidene)-3-triethoxysilyl-1-propaneamine at the end.
  • Tire 2 Bead portion 3: Sidewall portion 4: Tread portion 5: Carcass 6: Belt 6A, 6B: Belt layer 7: Bead core 8: Tread rubber layer

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  • Chemical Kinetics & Catalysis (AREA)
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  • Organic Chemistry (AREA)
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Abstract

La présente invention aborde le problème de la fourniture d'un pneumatique dans lequel les performances d'adhérence sur sol mouillé, les performances de faible consommation de carburant et les performances de résistance à l'usure sont améliorées sans dégrader la résistance à la coupure, et qui inhibe la décoloration de l'aspect extérieur. La solution est un pneumatique (1) pourvu d'une couche de caoutchouc de bande de roulement (8) et de couches de ceinture (6A, 6B) positionnées sur le côté interne dans la direction radiale du pneumatique. La couche de caoutchouc de bande de roulement (8) comprend un composite de caoutchouc contenant un SBR modifié spécifique, un SBR non modifié, de la silice, un agent de couplage au silane (A) ayant un groupe thiol, et un agent de couplage au silane (B) ayant une liaison sulfure. La quantité contenue de l'agent de couplage au silane (A) et la quantité totale contenue de l'agent de couplage au silane (A) et de l'agent de couplage au silane (B) se trouvent dans des plages spécifiques. Les couches de ceinture (6A, 6B) comprennent des cordes obtenues en torsadant ensemble des filaments qui, lorsque le diamètre des filaments est défini comme X (mm) et que la résistance à la traction est définie comme Y (MPa), satisfont à 4 000-2 000X ≤ Y ≤ 4 500-2 000X.
PCT/JP2024/032423 2023-11-24 2024-09-10 Pneumatique Pending WO2025109840A1 (fr)

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JP2023-199441 2023-11-24

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006175922A (ja) * 2004-12-21 2006-07-06 Bridgestone Corp 空気入りラジアルタイヤ
JP2012106570A (ja) * 2010-11-16 2012-06-07 Toyo Tire & Rubber Co Ltd 空気入りラジアルタイヤ
JP2013144720A (ja) * 2010-04-23 2013-07-25 Jsr Corp ゴム組成物及びタイヤ
JP2014098065A (ja) * 2012-11-13 2014-05-29 Toyo Tire & Rubber Co Ltd タイヤトレッド用ゴム組成物及び空気入りタイヤ
JP2017101352A (ja) * 2015-12-01 2017-06-08 株式会社ブリヂストン ゴム物品補強用スチールコードおよびこれを用いたタイヤ
JP2020204007A (ja) * 2019-06-19 2020-12-24 株式会社ブリヂストン タイヤ
JP2022018873A (ja) * 2020-07-16 2022-01-27 住友ゴム工業株式会社 タイヤ
JP2022107205A (ja) * 2021-01-08 2022-07-21 横浜ゴム株式会社 空気入りタイヤ

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006175922A (ja) * 2004-12-21 2006-07-06 Bridgestone Corp 空気入りラジアルタイヤ
JP2013144720A (ja) * 2010-04-23 2013-07-25 Jsr Corp ゴム組成物及びタイヤ
JP2012106570A (ja) * 2010-11-16 2012-06-07 Toyo Tire & Rubber Co Ltd 空気入りラジアルタイヤ
JP2014098065A (ja) * 2012-11-13 2014-05-29 Toyo Tire & Rubber Co Ltd タイヤトレッド用ゴム組成物及び空気入りタイヤ
JP2017101352A (ja) * 2015-12-01 2017-06-08 株式会社ブリヂストン ゴム物品補強用スチールコードおよびこれを用いたタイヤ
JP2020204007A (ja) * 2019-06-19 2020-12-24 株式会社ブリヂストン タイヤ
JP2022018873A (ja) * 2020-07-16 2022-01-27 住友ゴム工業株式会社 タイヤ
JP2022107205A (ja) * 2021-01-08 2022-07-21 横浜ゴム株式会社 空気入りタイヤ

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