WO2024111599A1 - Composition de caoutchouc pour pneu, caoutchouc de bande de roulement et pneu - Google Patents

Composition de caoutchouc pour pneu, caoutchouc de bande de roulement et pneu Download PDF

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Publication number
WO2024111599A1
WO2024111599A1 PCT/JP2023/041886 JP2023041886W WO2024111599A1 WO 2024111599 A1 WO2024111599 A1 WO 2024111599A1 JP 2023041886 W JP2023041886 W JP 2023041886W WO 2024111599 A1 WO2024111599 A1 WO 2024111599A1
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Prior art keywords
rubber
group
styrene
carbon atoms
mass
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PCT/JP2023/041886
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English (en)
Japanese (ja)
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正寛 川島
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株式会社ブリヂストン
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Publication of WO2024111599A1 publication Critical patent/WO2024111599A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
    • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
    • 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
    • C08L57/00—Compositions of unspecified polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C08L57/02—Copolymers of mineral oil hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L7/00—Compositions of natural rubber
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L91/00—Compositions of oils, fats or waxes; Compositions of derivatives thereof
    • 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, tread rubber, and tires.
  • Patent Document 1 discloses that the grip performance of a tire on both dry and wet road surfaces is improved by applying a rubber composition obtained by blending 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 the tire.
  • a rubber composition obtained by blending 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 the tire.
  • a rubber composition obtained by blending 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 the tire.
  • Patent Document 1 After investigations by the present inventors, it was found that while the technology described in Patent Document 1 can improve the wet performance of tires, there is still room for improvement in fuel economy and wear resistance.
  • an object of the present invention is to provide a rubber composition for tires that can solve the above-mentioned problems of the conventional technology and improve the fuel efficiency and wear resistance of tires, and a tread rubber made of such a rubber composition.
  • Another object of the present invention is to provide a tire having improved fuel economy and wear resistance.
  • a rubber composition for tires comprising a rubber component (A), an oil component (B), a resin component (C), and a filler (D),
  • the rubber component (A) contains natural rubber or synthetic isoprene rubber
  • the resin component (C) is at least partially hydrogenated,
  • the mass ratio of the resin component (C) to the oil component (B) is ⁇ 0.5 (1)
  • the rubber composition for tires satisfies the above requirements.
  • a tread rubber comprising the rubber composition for tires described in any one of [1] to [7].
  • a rubber composition for tires capable of improving the fuel economy and wear resistance of tires, and a tread rubber made of such a rubber composition.
  • a tire having improved fuel economy and wear resistance can be provided.
  • 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 sources, biological sources, and/or renewable sources.
  • the SP value (solubility parameter) of rubber component (A), such as natural rubber, synthetic isoprene rubber, styrene-butadiene rubber, etc., and resin component (C) is calculated according to the Fedors method.
  • the glass transition temperature of rubber component (A) such as natural rubber, synthetic isoprene rubber, styrene-butadiene rubber, etc., 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 resin component (C) is measured in accordance with JIS-K2207-1996 (ring and ball method).
  • the weight average molecular weight of resin component (C) is measured by gel permeation chromatography (GPC) and calculated as a polystyrene equivalent value.
  • the rubber composition for tires of this embodiment includes a rubber component (A), an oil component (B), a resin component (C), and a filler (D).
  • the rubber component (A) includes natural rubber (NR) or synthetic isoprene rubber (IR)
  • the resin component (C) is at least partially hydrogenated
  • the rubber composition for tires of this embodiment includes a carboxylic acid ester represented by the following formula (1):
  • the mass ratio of the resin component (C) to the oil component (B) is ⁇ 0.5 (1)
  • the present invention is characterized in that:
  • the rubber composition for tires of this embodiment contains an oil component (B) and a resin component (C) that is at least partially hydrogenated, but if the ratio of the oil component (B) to the resin component (C) is high, the wear resistance of the tire to which the rubber composition is applied will decrease.
  • the mass ratio of the resin component (C)/the oil component (B) is set to 0.5 or more, and the ratio of the oil component (B) to the resin component (C) is reduced, thereby improving the wear resistance of the tire to which the rubber composition is applied.
  • the rubber component (A) contains natural rubber (NR) and/or synthetic isoprene rubber (IR), so that the breaking strength of the rubber composition can be increased.
  • NR natural rubber
  • IR synthetic isoprene rubber
  • the rubber composition for tires of this embodiment contains the oil component (B) and the resin component (C) that is at least partially hydrogenated, and therefore can improve the wet performance of tires to which the rubber composition is applied.
  • the rubber composition for a tire of the present embodiment contains a rubber component (A), which contains natural rubber or polyisoprene rubber, and may further contain other rubber components. Note that the rubber component (A) is required to contain either natural rubber or polyisoprene rubber, and may contain both natural rubber and polyisoprene rubber.
  • the natural rubber (NR) and synthetic isoprene rubber (IR) are rubbers whose main skeleton is isoprene units.
  • the rubber component (A) contains natural rubber and/or synthetic isoprene rubber, which can increase the breaking strength of the rubber composition. As a result, the rolling resistance of a tire to which the rubber composition is applied can be reduced, and the fuel economy performance can be improved, and the wear resistance of the tire can also be improved.
  • the total content of the natural rubber and synthetic isoprene rubber is preferably 1 to 80 parts by mass, and more preferably 1 to 40 parts by mass, per 100 parts by mass of the rubber component (A).
  • the total content of the natural rubber and synthetic isoprene rubber is 1 to 80 parts by mass per 100 parts by mass of the rubber component (A)
  • the fuel efficiency and wet performance of a tire to which the rubber composition is applied can be further improved.
  • the total content of the natural rubber and synthetic isoprene rubber is 1 to 40 parts by mass per 100 parts by mass of the rubber component (A)
  • the total content of the natural rubber and synthetic isoprene rubber is more preferably 10 parts by mass or more per 100 parts by mass of the rubber component (A).
  • the rubber component (A) preferably further contains styrene-butadiene rubber (SBR).
  • SBR styrene-butadiene rubber
  • the styrene-butadiene rubber preferably has a glass transition temperature of less than -40°C, more preferably less than -45°C, even more preferably less than -50°C, and preferably higher than -90°C. If the glass transition temperature of the styrene-butadiene rubber is less than -40°C, the fuel economy and wear resistance of a tire to which the rubber composition is applied can be further improved. In addition, styrene-butadiene rubber with a glass transition temperature higher than -90°C is easy to synthesize.
  • the content of the styrene-butadiene rubber is preferably 20 to 99 parts by mass, more preferably 30 to 99 parts by mass, more preferably 40 to 99 parts by mass, more preferably 50 to 99 parts by mass, and even more preferably 60 to 99 parts by mass, per 100 parts by mass of the rubber component (A).
  • the content of the styrene-butadiene rubber is 60 to 99 parts by mass per 100 parts by mass of the rubber component (A)
  • the fuel economy and wet performance of a tire to which the rubber composition for tires is applied can be further improved.
  • the difference in SP value between the natural rubber or synthetic isoprene rubber and the styrene-butadiene rubber is preferably 0.3 (cal/cm 3 ) 1/2 or more, and more preferably 0.35 (cal/cm 3 ) 1/2 or more.
  • the difference in SP value between the natural rubber or synthetic isoprene rubber and the styrene-butadiene rubber is 0.3 (cal/cm 3 ) 1/2 or more, the natural rubber or synthetic isoprene rubber and the styrene-butadiene rubber tend to be incompatible.
  • the styrene-butadiene rubber preferably has a bound styrene content of less than 15% by mass.
  • the bound styrene content of the styrene-butadiene rubber means the ratio of styrene units contained in the styrene-butadiene rubber.
  • the bound styrene content of the styrene-butadiene rubber is less than 15% by mass, the glass transition temperature is likely to be low.
  • the bound styrene content of the styrene-butadiene rubber 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 content of the styrene-butadiene rubber is preferably 5% by mass or more, more preferably 7% by mass or more, and even more preferably 8% by mass or more, from the viewpoint of the wear resistance performance of a tire to which the rubber composition is applied.
  • the amount of bound styrene in the styrene-butadiene rubber can be adjusted by the amount of monomer used in polymerization of the styrene-butadiene rubber, the degree of polymerization, and the like.
  • the styrene-butadiene rubber is preferably modified with a modifier having a functional group containing a nitrogen atom and an alkoxy group.
  • a modifier having a functional group containing a nitrogen atom and an alkoxy group the balance of wet performance, fuel economy, and wear resistance of a tire to which the rubber composition is applied 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 functional group is 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, an isocyanuric acid triester residue, a cyclic tertiary amino group, a non-cyclic tertiary amino group, a nitrile group, a pyridine residue, an onium salt residue of a cyclic tertiary amine, and an onium salt residue of a non-cyclic terti
  • the styrene-butadiene rubber (SBR) is preferably modified with an aminoalkoxysilane compound, and more preferably has its terminals modified with an aminoalkoxysilane compound from the viewpoint of having a high affinity for the filler (D).
  • SBR styrene-butadiene rubber
  • the terminals of the styrene-butadiene rubber are modified with an aminoalkoxysilane compound, the interaction between the modified styrene-butadiene rubber and the filler (D) (particularly silica) becomes particularly large.
  • the modified site of the styrene-butadiene rubber may be the molecular terminal as described above, but may also be the main chain.
  • Styrene-butadiene rubber having modified molecular terminals can be produced by reacting various modifiers with the terminals of a styrene-butadiene copolymer having active terminals, for example, according to the methods described in WO 2003/046020 and JP 2007-217562 A.
  • the styrene-butadiene rubber having modified molecular terminals can be produced by reacting an aminoalkoxysilane compound with the terminals of a styrene-butadiene copolymer having an active terminal 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, and a partial ester having one or more hydroxyl groups.
  • 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 any of 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).
  • R 11 and R 12 each independently represent a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 18 carbon atoms, at least one of R 11 and R 12 is substituted with an amino group, a is an integer of 0 to 2, and when there are multiple OR 12 , each OR 12 may be the same or different, and no active proton is contained in the molecule.
  • the aminoalkoxysilane compound is also preferably an aminoalkoxysilane compound represented by the following general formula (ii).
  • 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 is 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.
  • SBR styrene-butadiene rubber
  • I a coupling agent represented by the following general formula (I)
  • R 1 , R 2 and R 3 each independently represent a single bond or an alkylene group having 1 to 20 carbon atoms.
  • R 4 , R 5 , R 6 , R 7 and R 9 each independently represent an alkyl group having 1 to 20 carbon atoms.
  • R 8 and R 11 each independently represent an alkylene group having 1 to 20 carbon atoms.
  • R 10 represents an alkyl group or a trialkylsilyl group having 1 to 20 carbon atoms.
  • m represents an integer of 1 to 3;
  • p represents 1 or 2.
  • i, j, and k each independently represent an integer of 0 to 6, provided that (i+j+k) is an integer of 3 to 10.
  • A represents a hydrocarbon group having 1 to 20 carbon atoms, or an organic group having at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom, a silicon atom, a sulfur atom and a phosphorus atom and having no active hydrogen.
  • the hydrocarbon group represented by A includes saturated, unsaturated, aliphatic and aromatic hydrocarbon groups.
  • organic group not having active hydrogen examples include organic groups not having a functional group having active hydrogen, such as a hydroxyl group (-OH), a secondary amino group (>NH), a primary amino group (-NH 2 ) or a sulfhydryl group (-SH).
  • the styrene-butadiene rubber modified with the coupling agent represented by the above general formula (I) has a weight average molecular weight (Mw) of 20 ⁇ 10 4 to 300 ⁇ 10 4 , contains 0.25 to 30 mass% of modified styrene-butadiene rubber having a molecular weight of 200 ⁇ 10 4 to 500 ⁇ 10 4 based on the total amount of the modified styrene-butadiene rubber, and preferably has a shrinkage factor (g') of less than 0.64.
  • Mw weight average molecular weight
  • g' shrinkage factor
  • a polymer having branches tends to have a smaller molecular size compared to a linear polymer having the same absolute molecular weight
  • the contraction factor (g') is an index of the ratio of the molecular size to that of a linear polymer having the same absolute molecular weight. That is, the contraction factor (g') tends to be smaller as the branching degree of the polymer increases.
  • the intrinsic viscosity is used as an index of the molecular size
  • the contraction factor (g') at each absolute molecular weight of the modified styrene-butadiene rubber is calculated, and the average value of the contraction factor (g') at the absolute molecular weight of 100 x 10 4 to 200 x 10 4 is taken as the contraction factor (g') of the modified styrene-butadiene rubber.
  • “branch” is formed by directly or indirectly bonding one polymer to another polymer.
  • “branching degree” is the number of polymers that are directly or indirectly bonded to one branch. For example, when five styrene-butadiene copolymer chains described below are indirectly bonded to each other via coupling residues described below, the degree of branching is 5.
  • the coupling residue is a structural unit of a modified styrene-butadiene rubber bonded to the styrene-butadiene copolymer chain, and is, for example, a structural unit derived from a coupling agent produced by reacting a styrene-butadiene copolymer described below with a coupling agent.
  • the styrene-butadiene copolymer chain is a structural unit of a modified styrene-butadiene rubber, and is, for example, a structural unit derived from a styrene-butadiene copolymer produced by reacting a styrene-butadiene copolymer described below with a coupling agent.
  • the shrinkage factor (g') is preferably less than 0.64, more preferably 0.63 or less, more preferably 0.60 or less, even more preferably 0.59 or less, and even more preferably 0.57 or less.
  • the lower limit of the shrinkage factor (g') is not particularly limited and may be equal to or less than the detection limit, but is preferably 0.30 or more, more preferably 0.33 or more, even more preferably 0.35 or more, and even more preferably 0.45 or more.
  • the shrinkage factor (g') tends to depend on the degree of branching, for example, the shrinkage factor (g') can be controlled using the degree of branching as an index.
  • the shrinkage factor (g') tends to be 0.59 or more and 0.63 or less
  • the shrinkage factor (g') tends to be 0.45 or more and 0.59 or less.
  • the styrene-butadiene rubber modified by the coupling agent represented by the general formula (I) preferably has a branch and a degree of branching of 5 or more.
  • the modified styrene-butadiene rubber has one or more coupling residues and a styrene-butadiene copolymer chain bonded to the coupling residue, and more preferably, the branch includes a branch in which 5 or more styrene-butadiene copolymer chains are bonded to one coupling residue.
  • the contraction factor (g') can be more reliably made less than 0.64.
  • the number of styrene-butadiene copolymer chains bonded to one coupling residue can be confirmed from the value of the contraction factor (g').
  • the modified styrene-butadiene rubber has branches, and the degree of branching is 6 or more.
  • the modified styrene-butadiene rubber has one or more coupling residues and a styrene-butadiene copolymer chain bonded to the coupling residue
  • the above-mentioned branches include branches in which 6 or more of the styrene-butadiene copolymer chains are bonded to one coupling residue.
  • the modified styrene-butadiene rubber has branches, and the degree of branching is more preferably 7 or more, and even more preferably 8 or more.
  • the upper limit of the degree of branching is not particularly limited, but is preferably 18 or less.
  • the modified styrene-butadiene rubber has one or more coupling residues and a styrene-butadiene copolymer chain bonded to the coupling residue, and further, it is more preferable that the above-mentioned branches include a branch in which 7 or more styrene-butadiene copolymer chains are bonded to one coupling residue, and it is particularly preferable that the above-mentioned branches include a branch in which 8 or more styrene-butadiene copolymer chains are bonded to one coupling residue.
  • the shrinkage factor (g') can be made 0.59 or less.
  • At least one end of the styrene-butadiene copolymer chain is bonded to a silicon atom of the coupling residue.
  • the ends of a plurality of styrene-butadiene copolymer chains may be bonded to one silicon atom.
  • an end of the styrene-butadiene copolymer chain and an alkoxy group or hydroxyl group having 1 to 20 carbon atoms may be bonded to one silicon atom, and as a result, that one silicon atom may constitute an alkoxysilyl group or silanol group having 1 to 20 carbon atoms.
  • the modified styrene-butadiene rubber can be an oil-extended rubber to which an extender oil has been added.
  • the modified styrene-butadiene rubber may be either non-oil-extended or oil-extended, but from the viewpoint of wear resistance, the Mooney viscosity measured at 100°C is preferably 20 or more and 100 or less, and more preferably 30 or more and 80 or less.
  • the weight average molecular weight (Mw) of the modified styrene-butadiene rubber is preferably 20 ⁇ 10 4 or more and 300 ⁇ 10 4 or less, more preferably 50 ⁇ 10 4 or more, more preferably 64 ⁇ 10 4 or more, and even more preferably 80 ⁇ 10 4 or more.
  • the weight average molecular weight is preferably 250 ⁇ 10 4 or less, more preferably 180 ⁇ 10 4 or less, and more preferably 150 ⁇ 10 4 or less.
  • the weight average molecular weight is 20 ⁇ 10 4 or more, the low loss property and abrasion resistance of the rubber composition can be sufficiently improved.
  • the weight average molecular weight is 300 ⁇ 10 4 or less, the processability of the rubber composition is improved.
  • the modified styrene-butadiene rubber preferably contains 0.25% by mass or more and 30% by mass or less of a modified styrene-butadiene rubber having a molecular weight of 200 ⁇ 10 4 or more and 500 ⁇ 10 4 or less (hereinafter also referred to as "specific high molecular weight component") relative to the total amount (100% by mass) of the modified styrene-butadiene rubber.
  • specific high molecular weight component a modified styrene-butadiene rubber having a molecular weight of 200 ⁇ 10 4 or more and 500 ⁇ 10 4 or less
  • the modified styrene-butadiene rubber preferably contains 1.0% by mass or more of the specific high molecular weight component, more preferably contains 1.4% by mass or more, even more preferably contains 1.75% by mass or more, even more preferably contains 2.0% by mass or more, particularly preferably contains 2.15% by mass or more, and extremely preferably contains 2.5% by mass or more.
  • the modified styrene-butadiene rubber contains the specific high molecular weight component in an amount of preferably 28% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and still more preferably 18% by mass or less.
  • the "molecular weight" of the rubber component is the standard polystyrene equivalent molecular weight obtained by GPC (gel permeation chromatography).
  • GPC gel permeation chromatography
  • the amount of an organic monolithium compound used as a polymerization initiator described later may be adjusted.
  • a method having a residence time distribution is used, that is, the time distribution of the propagation reaction is expanded.
  • the molecular weight distribution (Mw/Mn), which is expressed as the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), is preferably 1.6 or more and 3.0 or less. If the molecular weight distribution of the modified styrene-butadiene rubber is in this range, the rubber composition will have good processability.
  • the manufacturing method of the modified styrene-butadiene rubber is not particularly limited, but it preferably has a polymerization step in which butadiene and styrene are copolymerized using an organic monolithium compound as a polymerization initiator to obtain a styrene-butadiene copolymer, and a reaction step in which a pentafunctional or higher reactive compound (hereinafter also referred to as a "coupling agent”) is reacted with the active terminal of the styrene-butadiene copolymer.
  • a pentafunctional or higher reactive compound hereinafter also referred to as a "coupling agent”
  • the polymerization step is preferably a polymerization by a propagation reaction due to a living anionic polymerization reaction, which makes it possible to obtain a styrene-butadiene copolymer having an active terminal, and thus to obtain a modified styrene-butadiene rubber with a high modification rate.
  • the styrene-butadiene copolymer is obtained by copolymerizing 1,3-butadiene and styrene.
  • the amount of the organic monolithium compound used as a polymerization initiator is preferably determined depending on the molecular weight of the target styrene-butadiene copolymer or modified styrene-butadiene rubber.
  • the amount of monomers such as 1,3-butadiene and styrene used relative to the amount of polymerization initiator used is related to the degree of polymerization, that is, the number average molecular weight and/or the weight average molecular weight. Therefore, in order to increase the molecular weight, it is preferable to adjust the amount of polymerization initiator to a smaller amount, and in order to decrease the molecular weight, it is preferable to adjust the amount of polymerization initiator to a larger amount.
  • the organic monolithium compound is preferably an alkyllithium compound from the viewpoint of industrial availability and ease of control of the polymerization reaction.
  • a styrene-butadiene copolymer having an alkyl group at the polymerization initiation terminal is obtained.
  • the alkyllithium compound include n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenelithium.
  • n-butyllithium and sec-butyllithium are preferred from the viewpoint of industrial availability and ease of control of the polymerization reaction.
  • These organic monolithium compounds may be used alone or in combination of two or more.
  • examples of the polymerization reaction mode include a batch polymerization mode and a continuous polymerization mode.
  • the continuous mode one or more connected reactors can be used.
  • a tank type or a tube type reactor equipped with an agitator is used.
  • the monomer, the inert solvent, and the polymerization initiator are continuously fed into the reactor, a polymer solution containing the polymer is obtained in the reactor, and the polymer solution is continuously discharged.
  • a tank type reactor equipped with an agitator is used for example.
  • the monomer, the inert solvent, and the polymerization initiator are fed, and if necessary, the monomer is continuously or intermittently added during the polymerization, a polymer solution containing the polymer is obtained in the reactor, and the polymer solution is discharged after the polymerization is completed.
  • a continuous mode is preferred, which allows the polymer to be continuously discharged and used for the next reaction in a short time.
  • the polymerization step is preferably carried out in an inert solvent.
  • the solvent include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons.
  • specific examples of the hydrocarbon solvent include, but are not limited to, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene, and hydrocarbons consisting of mixtures thereof.
  • styrene-butadiene copolymer having a high concentration of active ends tends to be obtained, and a modified styrene-butadiene rubber with a high modification rate tends to be obtained, which is preferable.
  • a polar compound may be added.
  • styrene By adding a polar compound, styrene can be randomly copolymerized with 1,3-butadiene, and the polar compound tends to be usable as a vinylating agent for controlling the microstructure of the 1,3-butadiene portion.
  • polar compound examples include ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis(2-oxolanyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butylate, sodium tert-butylate, and sodium tert-amylate; and phosphine compounds such as triphenylphosphine. These polar compounds may be used alone or in combination of two or more.
  • ethers such as tetrahydrofuran, diethyl ether,
  • the polymerization temperature is preferably 0°C or higher, more preferably 120°C or lower, and particularly preferably 50°C or higher and 100°C or lower. By keeping the temperature in this range, it tends to be possible to ensure a sufficient amount of reaction of the coupling agent with the active terminals after the polymerization is completed.
  • the amount of bound butadiene in the styrene-butadiene copolymer or modified styrene-butadiene rubber is not particularly limited, but is preferably from 40% by mass to 100% by mass, and more preferably from 55% by mass to 80% by mass.
  • the amount of bound styrene in the styrene-butadiene copolymer or modified styrene-butadiene rubber is not particularly limited, but is preferably more than 0 mass% and not more than 60 mass%, and more preferably 20 mass% or more and not more than 45 mass%.
  • the low loss property and the wear resistance of the rubber composition can be further improved.
  • the amount of bound styrene can be measured by ultraviolet absorption of the phenyl group, from which the amount of bound butadiene can also be calculated.
  • the amount of vinyl bonds in the butadiene bond units is not particularly limited, but is preferably 10 mol% to 75 mol%, more preferably 20 mol% to 65 mol%.
  • the amount of vinyl bonds is within the above range, the low loss property and wear resistance of the rubber composition can be further improved.
  • the amount of vinyl bonds (1,2-bonds) in the butadiene bond units can be determined by the Hampton method [R. R. Hampton, Analytical Chemistry, 21, 923 (1949)].
  • the alkoxysilyl group of the coupling agent represented by the above general formula (I) tends to react with, for example, the active terminal of the styrene-butadiene copolymer, dissociating the alkoxylithium and forming a bond between the terminal of the styrene-butadiene copolymer chain and the silicon of the coupling residue.
  • the number of alkoxysilyl groups in the coupling residue is the total number of SiOR in one molecule of the coupling agent minus the number of SiORs reduced by the reaction.
  • the azasilacycle group in the coupling agent forms an >N-Li bond and a bond between the terminal of the styrene-butadiene copolymer and the silicon of the coupling residue.
  • the >N-Li bond tends to easily become >NH and LiOH due to water, etc. during finishing.
  • the alkoxysilyl group remaining unreacted in the coupling agent tends to easily become a silanol (Si-OH group) due to water, etc. during finishing.
  • the reaction temperature in the reaction step is preferably the same as the polymerization temperature of the styrene-butadiene copolymer, more preferably from 0° C. to 120° C., and even more preferably from 50° C. to 100° C.
  • the temperature change from the end of the polymerization step to the addition of the coupling agent is preferably 10° C. or less, more preferably 5° C. or less.
  • the reaction time in the reaction step is preferably 10 seconds or more, more preferably 30 seconds or more. From the viewpoint of the coupling rate, the time from the end of the polymerization step to the start of the reaction step is preferably shorter, and more preferably within 5 minutes.
  • the mixing in the reaction step may be performed by mechanical stirring, stirring with a static mixer, or the like.
  • the reaction step is also continuous.
  • the reactor used in the reaction step may be, for example, a tank type or a tube type equipped with a stirrer.
  • the coupling agent may be diluted with an inert solvent and continuously fed to the reactor.
  • the coupling agent may be added to the polymerization reactor, or may be transferred to another reactor to carry out the reaction step.
  • A is preferably represented by any one of the following general formulas (II) to (V).
  • a represented by any one of the general formulas (II) to (V) a modified styrene-butadiene rubber with superior performance can be obtained.
  • B 1 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. When a plurality of B 1s are present, each B 1 is independent.
  • B2 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms
  • B3 represents an alkyl group having 1 to 20 carbon atoms
  • a represents an integer of 1 to 10.
  • B4 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. When a plurality of B4s are present, each B4 is independent.
  • B5 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. When a plurality of B5s are present, each B5 is independent.
  • examples of the hydrocarbon group having 1 to 20 carbon atoms include an alkylene group having 1 to 20 carbon atoms.
  • A is represented by the general formula (II) or (III), and k is 0. More preferably, in the general formula (I), A is represented by the general formula (II) or (III), k represents 0, and in the general formula (II) or (III), a represents an integer of 2 to 10. More preferably, in said general formula (I), A is represented by said general formula (II), k represents 0, and in said general formula (II), a represents an integer of 2 to 10.
  • Examples of such coupling agents include bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, and tetrakis(3-trimethoxysilylpropyl).
  • the amount of the compound represented by general formula (I) added as the coupling agent can be adjusted so that the moles of the styrene-butadiene copolymer to the moles of the coupling agent react in the desired stoichiometric ratio, which tends to achieve the desired degree of branching.
  • the specific number of moles of the polymerization initiator is preferably 5.0 times or more, more preferably 6.0 times or more, relative to the number of moles of the coupling agent.
  • the number of functional groups of the coupling agent ((m-1) x i + p x j + k) is preferably an integer of 5 to 10, and more preferably an integer of 6 to 10.
  • the molecular weight distribution (Mw/Mn) of the styrene-butadiene copolymer is preferably 1.5 or more and 2.5 or less, more preferably 1.8 or more and 2.2 or less.
  • the obtained modified styrene-butadiene rubber is one in which a single peak is detected in the molecular weight curve by GPC.
  • Mp 1 peak molecular weight of the modified styrene-butadiene rubber as measured by GPC is Mp 1 and the peak molecular weight of the styrene-butadiene copolymer is Mp 2 .
  • Mp2 peak molecular weight of the modified styrene-butadiene rubber as measured by GPC is Mp 1 and the peak molecular weight of the styrene-butadiene copolymer is Mp 2 .
  • Mp2 is more preferably 20 ⁇ 10 4 or more and 80 ⁇ 10 4 or less
  • Mp1 is more preferably 30 ⁇ 10 4 or more and 150 ⁇ 10 4 or less.
  • Mp1 and Mp2 are determined by the method described in the examples below.
  • the modification rate of the modified styrene-butadiene rubber is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass or more. A modification rate of 30% by mass or more can further improve the low loss properties and wear resistance of the rubber composition.
  • a deactivator, neutralizing agent, etc. may be added to the copolymer solution as necessary.
  • deactivators include, but are not limited to, water; alcohols such as methanol, ethanol, isopropanol, etc.
  • neutralizing agents include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a highly branched carboxylic acid mixture having 9 to 11 carbon atoms, with the main carbon atom being 10); aqueous solutions of inorganic acids, and carbon dioxide gas.
  • antioxidant such as 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol)propionate, or 2-methyl-4,6-bis[(octylthio)methyl]phenol to the modified styrene-butadiene rubber.
  • BHT 2,6-di-tert-butyl-4-hydroxytoluene
  • n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol)propionate or 2-methyl-4,6-bis[(octylthio)methyl]phenol
  • the modified styrene-butadiene rubber can be obtained from the polymer solution by known methods. Examples of such methods include a method in which the solvent is separated by steam stripping or the like, the polymer is filtered, and then dehydrated and dried to obtain the polymer, a method in which the polymer is concentrated in a flashing tank and then devolatilized using a vent extruder or the like, and a method in which the polymer is directly devolatilized using a drum dryer or the like.
  • the modified styrene-butadiene rubber obtained by reacting the coupling agent represented by the above general formula (I) with a styrene-butadiene copolymer is represented, for example, by the following general formula (VI).
  • D represents a styrene-butadiene copolymer chain
  • the weight average molecular weight of the styrene-butadiene copolymer chain is preferably 10 ⁇ 10 4 to 100 ⁇ 10 4.
  • the styrene-butadiene copolymer chain is a structural unit of a modified styrene-butadiene rubber, and is, for example, a structural unit derived from a styrene-butadiene copolymer produced by reacting a styrene-butadiene copolymer with a coupling agent.
  • R 12 , R 13 and R 14 each independently represent a single bond or an alkylene group having 1 to 20 carbon atoms.
  • R 15 and R 18 each independently represent an alkyl group having 1 to 20 carbon atoms.
  • R 16 , R 19 , and R 20 each independently represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.
  • R 17 and R 21 each independently represent an alkylene group having 1 to 20 carbon atoms.
  • R 22 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.
  • m and x are integers of 1 to 3, with x ⁇ m; p is 1 or 2; y is an integer of 1 to 3, with y ⁇ (p+1); and z is an integer of 1 or 2.
  • R 12 to R 22 , m, p, x, y, and z are each independent and may be the same or different.
  • i represents an integer from 0 to 6
  • j represents an integer from 0 to 6
  • k represents an integer from 0 to 6
  • (i+j+k) is an integer from 3 to 10
  • ((x ⁇ i)+(y ⁇ j)+(z ⁇ k)) is an integer from 5 to 30.
  • A represents a hydrocarbon group having 1 to 20 carbon atoms, or an organic group having at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom, a silicon atom, a sulfur atom, and a phosphorus atom, and having no active hydrogen.
  • the hydrocarbon group represented by A includes saturated, unsaturated, aliphatic, and aromatic hydrocarbon groups.
  • Examples of the organic group having no active hydrogen include organic groups having no functional groups having active hydrogen, such as a hydroxyl group (-OH), a secondary amino group (>NH), a primary amino group (-NH 2 ), or a sulfhydryl group (-SH).
  • A is preferably represented by any one of the above general formulas (II) to (V).
  • a represented by any one of the general formulas (II) to (V) the low loss properties and wear resistance of the rubber composition can be further improved.
  • modified styrene-butadiene rubber-- It is also preferable that at least one end of the styrene-butadiene rubber (SBR) is modified with a modifying agent containing a compound (alkoxysilane) represented by the following general formula (1).
  • SBR styrene-butadiene rubber
  • the rubber component a styrene-butadiene rubber modified with a modifier containing a compound represented by the above general formula (1) containing an oligosiloxane, which is a filler affinity functional group, and a tertiary amino group
  • the dispersibility of fillers such as silica can be improved.
  • the rubber composition of the present invention has improved filler dispersibility, and therefore has significantly improved low loss properties, reducing the rolling resistance of tires to which the rubber composition is applied, and improving fuel efficiency.
  • R 1 to R 8 are each independently an alkyl group having 1 to 20 carbon atoms; L 1 and L 2 are each independently an alkylene group having 1 to 20 carbon atoms; and n is an integer of 2 to 4.
  • R 1 to R 4 may each independently be a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms.
  • R 1 to R 4 When R 1 to R 4 are substituted, they may each independently be substituted with one or more substituents selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a cycloalkoxy group having 4 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an alkanoyloxy group having 2 to 12 carbon atoms (Ra-COO-, where Ra is an alkyl group having 1 to 9 carbon atoms), an aralkyloxy group having 7 to 13 carbon atoms, an arylalkyl group having 7 to 13 carbon atoms, and an alkylaryl group having 7 to 13 carbon atoms
  • R 1 to R 4 may be a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, and even more specifically, R 1 to R 4 may be each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.
  • R 5 to R 8 are each independently a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, specifically, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, more specifically, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and when substituted, may be substituted with the substituents described above for R 1 to R 4 .
  • R 5 to R 8 are not alkyl groups but hydrolyzable substituents, the bonds N-R 5 R 6 and N-R 7 R 8 may be hydrolyzed to N-H in the presence of moisture, which may adversely affect the processability of the polymer.
  • R 1 to R 4 can be a methyl group or an ethyl group
  • R 5 to R 8 can be an alkyl group having 1 to 10 carbon atoms.
  • the amino groups in the compound represented by formula (1) are preferably tertiary amino groups.
  • the tertiary amino groups provide the compound represented by formula (1) with better processability when used as a modifying agent.
  • a protecting group for protecting an amino group is bonded to R 5 to R 8 or when hydrogen is bonded to R 5 to R 8 , it may be difficult to realize the effect of the compound represented by formula (1).
  • the anion reacts with hydrogen during the modification process and loses reactivity, making the modification reaction itself impossible, and when a protecting group is bonded, the modification reaction takes place, but in the state bonded to the polymer end, it is deprotected by hydrolysis during post-processing to become a primary or secondary amino group, and the deprotected primary or secondary amino group may cause an increase in the viscosity of the compound during subsequent blending, which may cause a decrease in processability.
  • L 1 and L 2 in the compound represented by the formula (1) are each independently a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms. More specifically, L 1 and L 2 can each independently be an alkylene group having 1 to 10 carbon atoms, and even more specifically, an alkylene group having 1 to 6 carbon atoms, such as a methylene group, an ethylene group, or a propylene group.
  • the L 1 and L 2 are each independently an alkylene group having 1 to 3 carbon atoms such as a methylene group, an ethylene group, or a propylene group, and more specifically, a propylene group.
  • L 1 and L 2 may be substituted with the substituents described above for R 1 to R 4 .
  • the compound represented by the formula (1) is preferably, for example, any one of the compounds represented by the following structural formulas (1-1) to (1-5), because this allows for more excellent low loss properties to be achieved.
  • the compound represented by formula (1) has an alkoxysilane structure that bonds with the active terminal of the styrene-butadiene copolymer, while the Si-O-Si structure and three or more amino groups bonded to the terminal show affinity for the filler (D) such as silica, and therefore can promote the bonding between the filler (D) and the modified styrene-butadiene rubber compared to conventional modifiers containing one amino group in the molecule.
  • the degree of bonding of the active terminal of the styrene-butadiene copolymer is uniform, and when the change in molecular weight distribution before and after coupling is observed, the molecular weight distribution after coupling does not increase and remains constant compared to before.
  • the compound represented by the formula (1) can be produced through a condensation reaction represented by the following reaction scheme.
  • R 1 to R 8 , L 1 and L 2 , and n are the same as those defined in the above formula (1), and R′ and R′′ are any substituents that do not affect the condensation reaction.
  • R′ and R′′ can each independently be the same as any one of R 1 to R 4 .
  • the reaction in the above reaction scheme proceeds in the presence of an acid, and the acid can be any acid that is generally used in condensation reactions, without any restrictions.
  • the acid can be any acid that is generally used in condensation reactions, without any restrictions.
  • Those skilled in the art can select an optimal acid depending on various process variables such as the type of reactor in which the reaction is carried out, the starting materials, and the reaction temperature.
  • the styrene-butadiene rubber modified with a modifier containing the compound represented by formula (1) can have a narrow molecular weight distribution (Mw/Mn, also called “polydispersity index (PDI)”) of 1.1 to 3.0. If the molecular weight distribution of the modified styrene-butadiene rubber exceeds 3.0 or is less than 1.1, there is a risk of the tensile properties and viscoelasticity decreasing when applied to a rubber composition.
  • Mw/Mn also called “polydispersity index (PDI)
  • the molecular weight distribution of the modified styrene-butadiene rubber is preferably in the range of 1.3 to 2.0.
  • the modified styrene-butadiene rubber has a molecular weight distribution similar to that of the styrene-butadiene copolymer before modification.
  • the molecular weight distribution of the modified styrene-butadiene rubber can be calculated from the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn).
  • the number average molecular weight (Mn) is the common average of the molecular weights of individual polymers calculated by measuring the molecular weights of n polymer molecules, calculating the sum of the molecular weights, and dividing by n
  • the weight average molecular weight (Mw) represents the molecular weight distribution of a polymer composition.
  • the average of the total molecular weight can be expressed in grams per mole (g/mol).
  • the weight average molecular weight and number average molecular weight are each a polystyrene-equivalent molecular weight analyzed by gel permeation chromatography (GPC).
  • the modified styrene-butadiene rubber satisfies the above-mentioned molecular weight distribution conditions, and at the same time, the number average molecular weight (Mn) can be 50,000 g/mol to 2,000,000 g/mol, more specifically, 200,000 g/mol to 800,000 g/mol, and the weight average molecular weight (Mw) can be 100,000 g/mol to 4,000,000 g/mol, more specifically, 300,000 g/mol to 1,500,000 g/mol.
  • the weight average molecular weight (Mw) of the modified styrene-butadiene rubber is less than 100,000 g/mol or the number average molecular weight (Mn) is less than 50,000 g/mol
  • the tensile properties may be deteriorated when applied to a rubber composition.
  • the weight average molecular weight (Mw) is more than 4,000,000 g/mol or the number average molecular weight (Mn) is more than 2,000,000 g/mol
  • the processability of the modified styrene-butadiene rubber is deteriorated, the workability of the rubber composition is deteriorated, kneading becomes difficult, and it may be difficult to sufficiently improve the physical properties of the rubber composition.
  • the modified styrene-butadiene rubber satisfies the conditions of weight average molecular weight (Mw) and number average molecular weight (Mn) together with the molecular weight distribution
  • Mw weight average molecular weight
  • Mn number average molecular weight
  • the modified styrene-butadiene rubber preferably has a vinyl bond content in the butadiene portion of 5% or more, more preferably 10% or more, and more preferably 60% or less.
  • the glass transition temperature can be adjusted to an appropriate range.
  • the modified styrene-butadiene rubber may have a Mooney viscosity (MV) at 100° C. of 40 to 140, specifically 60 to 100.
  • MV Mooney viscosity
  • the Mooney viscosity can be measured using a Mooney viscometer, for example, MV2000E manufactured by Monsanto, at 100° C., rotor speed 2 ⁇ 0.02 rpm, and a large rotor.
  • the sample used here is left at room temperature (23 ⁇ 3° C.) for 30 minutes or more, and then 27 ⁇ 3 g of the sample is taken and filled into the die cavity, and the platen is operated to measure.
  • the modified styrene-butadiene rubber is preferably modified at one end with a modifier containing a compound represented by the above general formula (1), and is preferably further modified at the other end with a modifier containing a compound represented by the following general formula (2).
  • a modifier containing a compound represented by the following general formula (2) By modifying both ends of the modified styrene-butadiene rubber, the dispersibility of the filler (D) in the rubber composition is further improved, and a tire to which the rubber composition is applied can achieve both low fuel consumption performance and wet performance at a higher level.
  • R 9 to R 11 are each independently hydrogen; an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms, a heteroalkenyl group having 2 to 30 carbon atoms; a heteroalkynyl group having 2 to 30 carbon atoms; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 6 to 30 carbon atoms; or a heterocyclic group having 3 to 30 carbon atoms.
  • R 12 is a single bond; an alkylene group having 1 to 20 carbon atoms which is substituted or unsubstituted with a substituent; a cycloalkylene group having 5 to 20 carbon atoms which is substituted or unsubstituted with a substituent; or an arylene group having 5 to 20 carbon atoms which is substituted or unsubstituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.
  • R 13 is an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms; a heteroalkenyl group having 2 to 30 carbon atoms; a heteroalkynyl group having 2 to 30 carbon atoms; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 6 to 30 carbon atoms; a heterocyclic group having 3 to 30 carbon atoms; or a functional group represented by the following general formula (2a) or general formula (2b), where m is an integer of 1 to 5, and at least one of R 13 is a functional group represented by the following general formula (2a) or general formula (2b), and when m is an integer of 2 to 5, the multiple R 13 may be the same as or different from each other.
  • R 14 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms; a substituted or unsubstituted cycloalkylene group having 5 to 20 carbon atoms; or a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.
  • R 15 and R 16 are each independently an alkylene group having 1 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.
  • R 17 is hydrogen; an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms; a heteroalkenyl group having 2 to 30 carbon atoms; a heteroalkynyl group having 2 to 30 carbon atoms; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 6 to 30 carbon atoms; or a heterocyclic group having 3 to 30 carbon atoms; and X is an N, O, or S atom, with the proviso that when X is O or S, R 17 does not exist.
  • R 18 is a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms; a substituted or unsubstituted cycloalkylene group having 5 to 20 carbon atoms; or a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.
  • R 19 and R 20 are each independently an alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; an alkynyl group having 2 to 30 carbon atoms; a heteroalkyl group having 1 to 30 carbon atoms; a heteroalkenyl group having 2 to 30 carbon atoms; a heteroalkynyl group having 2 to 30 carbon atoms; a cycloalkyl group having 5 to 30 carbon atoms; an aryl group having 6 to 30 carbon atoms; or a heterocyclic group having 3 to 30 carbon atoms.
  • R 9 to R 11 are each independently hydrogen; an alkyl group having 1 to 10 carbon atoms; an alkenyl group having 2 to 10 carbon atoms; or an alkynyl group having 2 to 10 carbon atoms;
  • R 12 is a single bond; or an unsubstituted alkylene group having 1 to 10 carbon atoms;
  • R 13 is an alkyl group having 1 to 10 carbon atoms; an alkenyl group having 2 to 10 carbon atoms; an alkynyl group having 2 to 10 carbon atoms; or a functional group represented by the above general formula (2a) or general formula (2b); in the above general formula (2a), R 14 is an unsubstituted alkylene group having 1 to 10 carbon atoms; R 15 and R 16 are each independently an unsubstituted alkylene group having 1 to 10 carbon atoms; R In the above general formula (2b), R 18 is an unsubstituted alkylene group having 1 to 10 carbon atoms,
  • the compound represented by the above general formula (2) can be a compound represented by the following structural formulas (2-1) to (2-3).
  • the modifying agent containing the compound represented by formula (2) is used as a modification initiator.
  • a butadiene monomer and a styrene monomer are polymerized in a hydrocarbon solvent in the presence of a modifying agent containing the compound represented by formula (2), whereby a modifying group derived from the compound represented by formula (2) can be imparted to the styrene-butadiene copolymer.
  • the rubber component (A) may further contain other rubbers, and the content of the other rubbers in 100 parts by mass of the rubber component (A) is preferably 35 parts by mass or less.
  • other rubbers include chloroprene rubber (CR), butyl rubber (IIR), halogenated butyl rubber, ethylene-propylene rubber (EPR, EPDM), fluororubber, silicone rubber, and urethane rubber.
  • chloroprene rubber (CR) is preferred.
  • the rubber component (A) does not contain butadiene rubber (BR).
  • BR butadiene rubber
  • the rubber composition for tires of this embodiment contains an oil component (B).
  • the grip performance such as wet performance of the tire can be improved.
  • the rubber composition containing the oil component (B) the rubber composition is better cohesive during kneading, and the workability during kneading of the rubber composition is improved.
  • the oil component (B) is a general term for a liquid oil [more specifically, a liquid oil at 25° C. (room temperature)] added as a compounding agent to the rubber composition, and an extender oil contained in the rubber component (A).
  • the oil component (B) include petroleum-based softeners such as aromatic oils, paraffinic oils, and naphthenic oils; and vegetable-based softeners such as palm oil, castor oil, cottonseed oil, and soybean oil.
  • a liquid polymer can also be used as the oil component (B).
  • the liquid polymer is liquid at 25° C. (room temperature) and preferably has a weight average molecular weight of 5,000 to 100,000.
  • liquid polymers examples include liquid polybutadiene, liquid polyisoprene, and liquid polystyrene-butadiene.
  • petroleum-based softeners such as aromatic oils, paraffinic oils, and naphthenic oils are preferred as the oil component (B).
  • a naphthenic oil containing asphalt is preferable.
  • the rubber composition contains a naphthenic oil containing asphalt, the rubber composition is more easily mixed and the workability during mixing of the rubber composition is further improved.
  • the naphthenic oil containing asphalt is preferably a mixture of naphthenic base oil and asphalt in a mass ratio of (95/5) to (30/70). If the mass ratio is within this range, the compatibility between the rubber component (A) and the oil component (B) is further improved.
  • the naphthenic base oil is preferably a hydrogenated naphthenic base oil, and more preferably a hydrogenated naphthenic base oil obtained by subjecting aromatic oils or naphthenic oils to a high degree of hydrorefining using a high-pressure, high-temperature hydrorefining production apparatus.
  • hydrogenated naphthenic base oils are available as commercial products, such as SNH8, SNH46, SNH220, and SNH440 (all trademarks) manufactured by Sankyo Yuka Kogyo Co., Ltd.
  • the asphalt to be mixed with the naphthenic base oil preferably contains an asphaltene component of 5 mass% or less, taking into consideration compatibility with the rubber component (A) used and the effect of improving the cohesion during kneading of the rubber composition.
  • the asphaltene component is quantified by composition analysis measured in accordance with the JPI method [Japan Petroleum Institute Standard JPI-5S-22-83 (established in 1983), standard name "Asphalt Composition Analysis Method by Column Chromatography”].
  • Such asphalt is preferably straight asphalt, and particularly preferably naphthenic straight asphalt.
  • the asphalt preferably has a kinetic viscosity at 120°C of 300 mm 2 /sec or less.
  • the method for mixing the asphalt is not particularly limited, but from the standpoint of ease of preparation and economic efficiency, a method in which the asphalt is dissolved in a naphthenic base oil (including extender oil and blending oil) is preferred.
  • a naphthenic oil containing asphalt a product name "A/O Mix” manufactured by Sankyo Yuka Kogyo Co., Ltd., which is obtained by mixing a hydrogenated naphthenic base oil produced by a high-pressure, high-temperature hydrorefining unit with a naphthenic straight asphalt containing 5 mass % or less asphaltene in a mass ratio (63/37), is preferred.
  • the content of the oil component (B) is selected so that the mass ratio with the resin component (C) described below satisfies resin component (C)/oil component (B) ⁇ 0.5.
  • the content of the oil component (B) is preferably 1 part by mass or more, more preferably 2.5 parts by mass or more, and preferably 40 parts by mass or less, and more preferably 30 parts by mass or less, per 100 parts by mass of the rubber component (A).
  • the content of the oil component (B) is 2.5 parts by mass or more per 100 parts by mass of the rubber component (A)
  • the effect of improving the wet performance of the tire is increased.
  • the content of the oil component (B) is 30 parts by mass or less per 100 parts by mass of the rubber component (A)
  • the wear resistance of the tire is further improved.
  • the rubber composition for tires of this embodiment contains a resin component (C), which is at least partially hydrogenated.
  • a resin component (C) which is at least partially hydrogenated.
  • compatibility with natural rubber and/or synthetic isoprene rubber is increased, the mobility of the rubber component (A) is controlled, and the hysteresis loss (tan ⁇ ) in the low temperature range can be improved, thereby improving the wet performance of a tire to which the rubber composition is applied.
  • the rubber composition for a tire according to the present embodiment has the following formula (1):
  • the mass ratio of the resin component (C) to the oil component (B) is ⁇ 0.5 (1)
  • the mass ratio of resin component (C)/oil component (B) is preferably 0.8 or more, more preferably 1.0 or more, and is preferably 20 or less, more preferably 18 or less.
  • the resin component (C) preferably has an SP value difference of 1.40 (cal/cm 3 ) 1/2 or less from the natural rubber or synthetic isoprene rubber.
  • the SP value difference between the resin component (C) and the natural rubber or synthetic isoprene rubber is 1.40 (cal/cm 3 ) 1/2 or less, the compatibility of the resin component (C) with the natural rubber and/or synthetic isoprene rubber is increased, the mobility of the rubber component (A) is controlled, and the hysteresis loss (tan ⁇ ) in the low temperature region can be improved, thereby improving the wet performance of a tire to which the rubber composition is applied.
  • the difference in SP value between resin component (C) and natural rubber and/or synthetic isoprene rubber is preferably 1.35 (cal/ cm3 ) 1/2 or less, more preferably 0.50 (cal/ cm3 ) 1/2 or less, more preferably 0.45 (cal/ cm3 ) 1/2 or less, more preferably 0.3 (cal/ cm3 ) 1/2 or less, and even more preferably 0.25 (cal/ cm3 ) 1/2 or less.
  • the resin component (C) 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.
  • the softening point of the resin component (C) is higher than 110°C, the tire to which the rubber composition is applied can be sufficiently reinforced, and the wear resistance can be further improved.
  • the softening point of the resin component (C) 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 component (C) is preferably 160°C or lower, more preferably 150°C or lower, more preferably 145°C or lower, and even more preferably 141°C or lower.
  • the resin component (C) in terms of polystyrene is 200 g/mol or more, the resin component (C) is less likely to precipitate from the tire and the effects of the resin component (C) can be sufficiently exhibited, and when the weight average molecular weight is 1600 g/mol or less, the resin component (C) is easily compatible with the rubber component.
  • the polystyrene-equivalent weight average molecular weight of the resin component (C) is preferably 500 g/mol or more, more preferably 550 g/mol or more, more preferably 600 g/mol or more, still 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 component (C) is more preferably 1570 g/mol or less, more preferably 1530 g/mol or less, more preferably 1500 g/mol or less, more preferably 1470 g/mol or less, more preferably 1430 g/mol or less, more preferably 1400 g/mol or less, more preferably 1370 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 ratio (Ts HR /Mw HR ) of the softening point (Ts HR ) (unit: ° C.) of the resin component (C) to the polystyrene-equivalent weight average molecular weight (Mw HR ) (unit: g/mol) of the resin component (C) is preferably 0.07 or more, more preferably 0.083 or more, more preferably 0.095 or more, more preferably 0.104 or more, more preferably 0.125 or more, more preferably 0.135 or more, more preferably 0.14 or more, and even more preferably 0.141 or more.
  • the ratio (Ts HR /Mw HR ) is preferably 0.25 or less, preferably 0.24 or less, preferably 0.23 or less, preferably 0.19 or less, more preferably 0.18 or less, and even more preferably 0.17 or less.
  • the above-mentioned at least partially hydrogenated resin component (C) means a resin obtained by reducing and hydrogenating a resin.
  • resins that can be used as raw materials for the hydrogenated resin component (C) include C5 resins, C5 - C9 resins, C9 resins, terpene resins, dicyclopentadiene resins, and terpene-aromatic compound resins. These resins may be used alone or in combination of two or more.
  • 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 specific 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 (A).
  • “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 C9 resin refers to a C9 synthetic petroleum resin, for example, a solid polymer obtained by polymerizing a C9 fraction using a Friedel-Crafts type catalyst such as AlCl3 or BF3 .
  • Examples of C9 resins include copolymers containing indene, ⁇ -methylstyrene, vinyltoluene, or the like as main components.
  • 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 that is the raw material for the hydrogenated resin component (C) may contain, 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 component (C) is preferably at least one selected from the group consisting of hydrogenated C5 resins, hydrogenated C5 - C9 resins, hydrogenated dicyclopentadiene resins (hydrogenated DCPD resins), and hydrogenated terpene resins, more preferably at least one selected from the group consisting of hydrogenated C5 resins and hydrogenated C5 - C9 resins, and even more preferably hydrogenated C5 resins.
  • the resin has a hydrogenated DCPD structure or a hydrogenated cyclic structure in at least the monomer.
  • the resin component (C) is at least one selected from the group consisting of hydrogenated C5 resins, hydrogenated C5 - C9 resins, hydrogenated dicyclopentadiene resins, and hydrogenated terpene resins, the wet performance of the tire to which the rubber composition is applied can be further improved, and the fuel efficiency can be further improved.
  • the rubber composition for a tire according to the present embodiment has the following formula (2):
  • the mass ratio of the resin component (C) to the total amount of the natural rubber and the polyisoprene rubber is ⁇ 0.5 (2)
  • mass ratio of resin component (C) to the total amount of natural rubber and polyisoprene rubber [mass ratio of resin component (C)/total amount of natural rubber and polyisoprene rubber] is 0.5 or more, the wet performance of a tire to which the rubber composition is applied can be further improved.
  • the mass ratio of resin component (C) to the total amount of natural rubber and polyisoprene rubber is preferably 0.65 or more, more preferably 0.7 or more, and more preferably 0.8 or more, and is preferably 2.0 or less, more preferably 1.9 or less, and even more preferably 1.8 or less.
  • the content of the resin component (C) is preferably 1 part by mass or more and less than 50 parts by mass per 100 parts by mass of the rubber component (A).
  • the content of the resin component (C) in the rubber composition is 1 part by mass or more per 100 parts by mass of the rubber component (A)
  • the effect of the resin component (C) is fully manifested, and when the content is less than 50 parts by mass, the resin component (C) is less likely to precipitate from the tire, and the effect of the resin component (C) can be fully manifested.
  • the content of the resin component (C) in the rubber composition is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, more preferably 9 parts by mass or more, more preferably 15 parts by mass or more, and even more preferably 17 parts by mass or more per 100 parts by mass of the rubber component.
  • the content of the resin component (C) in the rubber composition is more preferably 45 parts by mass or less, and even more preferably 40 parts by mass or less, per 100 parts by mass of the rubber component (A).
  • the rubber composition for a tire of the present embodiment contains a filler (D).
  • a filler (D) By containing the filler (D), the reinforcing property of the rubber composition is improved.
  • the content of the filler (D) in the rubber composition is preferably in the range of 40 to 125 parts by mass relative to 100 parts by mass of the rubber component (A).
  • the content of the filler (D) in the rubber composition is 40 parts by mass or more relative to 100 parts by mass of the rubber component (A), the reinforcement of the tire to which the rubber composition is applied is sufficient, and the wear resistance performance can be further improved, and when the content is 125 parts by mass or less, the elastic modulus of the rubber composition does not become too high, and the wet performance of the tire to which the rubber composition is applied is further improved.
  • the content of the filler (D) in the rubber composition is more preferably 45 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 55 parts by mass or more relative to 100 parts by mass of the rubber component (A).
  • the content of the filler (D) in the rubber composition is more preferably 105 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 95 parts by mass or less, per 100 parts by mass of the rubber component (A).
  • the filler (D) preferably contains silica, and more preferably contains silica having 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 tire to which the rubber composition is applied can be sufficiently reinforced, and the rolling resistance of the tire can be further reduced.
  • the nitrogen adsorption specific surface area (BET method) of silica is less than 330 m 2 /g, the elastic modulus of the rubber composition does not become too high, and the wet performance of the tire to which the rubber composition is applied is further improved.
  • the nitrogen adsorption specific surface area (BET method) of silica is preferably 110 m 2 /g or more, preferably 130 m 2 /g or more, preferably 150 m 2 /g or more, and more preferably 180 m 2 /g or more.
  • the nitrogen adsorption specific surface area (BET method) of 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.
  • silica examples include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, etc., and among these, wet silica is preferred. These silicas may be used alone or in combination of two or more types.
  • the content of silica in the rubber composition is preferably 40 parts by mass or more, more preferably 45 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 55 parts by mass or more, per 100 parts by mass of rubber component (A). Also, from the viewpoint of further improving the wet performance of the tire, the content of silica in the rubber composition is preferably 125 parts by mass or less, more preferably 105 parts by mass or less, more preferably 100 parts by mass or less, and even more preferably 95 parts by mass or less, per 100 parts by mass of rubber component (A).
  • the filler (D) preferably contains carbon black, which reinforces the rubber composition and improves 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 content of carbon black in the rubber composition is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, per 100 parts by mass of the rubber component (A). Also, from the viewpoint of workability of the rubber composition, the content of carbon black in the rubber composition is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, per 100 parts by mass of the rubber component (A).
  • the proportion of silica in the total amount of silica and carbon black is preferably 80% by mass or more and less than 100% by mass, and more preferably 90% by mass or more and less than 100% by mass.
  • the proportion of silica is 80% by mass or more, the mechanical strength of a tire to which the rubber composition is applied is improved, and the rolling resistance can be further reduced.
  • the filler (D) may contain, in addition to silica and carbon black, inorganic fillers such as clay, talc, calcium carbonate, and aluminum hydroxide.
  • the above-mentioned other fillers are preferably contained in the range where the silica content in the filler (D) is 70% by mass or more.
  • the silica content in the filler (D) is more preferably 80% by mass or more, even more preferably 85% by mass or more, and even more preferably 90% by mass or more and less than 100% by mass.
  • the rubber composition for tires of this embodiment may contain a styrene-based thermoplastic elastomer (TPS).
  • the styrene-based thermoplastic elastomer (TPS) has a styrene-based polymer block (hard segment) and a conjugated diene-based polymer block (soft segment), and the styrene-based polymer portion forms a physical crosslink to become a crosslinking point, while the conjugated diene-based polymer block imparts rubber elasticity.
  • the double bonds of the conjugated diene-based polymer block (soft segment) may be partially or completely hydrogenated.
  • the styrene-based thermoplastic elastomer (TPS) is thermoplastic, whereas the rubber component (A) (preferably, a diene-based rubber) is not thermoplastic. Therefore, in this specification, the styrene-based thermoplastic elastomer (TPS) is not included in the rubber component (A).
  • the content of the styrene-based thermoplastic elastomer (TPS) is preferably in the range of 1 to 30 parts by mass per 100 parts by mass of the rubber component.
  • the styrene-based thermoplastic elastomer may include styrene/butadiene/styrene (SBS) block copolymer, styrene/isoprene/styrene (SIS) block copolymer, styrene/butadiene/isoprene/styrene (SBIS) block copolymer, styrene/butadiene (SB) block copolymer, styrene/isoprene (SI) block copolymer, styrene/butadiene/isoprene (SBI) block copolymer, styrene/ethylene/butylene/styrene (SEBS) block copolymer, styrene/ethylene/propylene/styrene (SEPS) block copolymer, styrene/ethylene/ethylene/propylene/styrene (S
  • the rubber composition for tires of this embodiment may contain the above-mentioned rubber component (A), oil component (B), resin component (C), filler (D), and styrene-based thermoplastic elastomer, as well as various components commonly used in the rubber industry, such as silane coupling agents, antioxidants, waxes, processing aids, stearic acid, zinc oxide (zinc oxide), vulcanization accelerators, vulcanizing agents, etc., which may be appropriately selected within ranges that do not impair the objects of the present invention. Commercially available products can be suitably used as these compounding ingredients.
  • silane coupling agent 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-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N
  • 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, but is preferably in the range of 0.1 to 10 parts by mass, and more preferably 1 to 8 parts by mass, per 100 parts by mass of the rubber component (A).
  • 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 (A).
  • 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 (A).
  • the method for producing the rubber composition is not particularly limited, but for example, the rubber composition can be produced by blending various components appropriately selected as necessary with the above-mentioned rubber component (A), oil component (B), resin component (C) and filler (D), and 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, the kneading temperature, the kneading time, the type of kneading device, and other conditions can be appropriately selected according to the purpose.
  • kneading devices include Banbury mixers, intermixes, kneaders, rolls, and the like that are typically used for kneading rubber compositions.
  • heat-in conditions there are no particular limitations on the heat-in conditions, and the heat-in temperature, heat-in time, heat-in equipment, and other conditions can be appropriately selected depending on the purpose.
  • the heat-in equipment include a heat-in roll machine that is typically used for heat-in 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 tread rubber of the present embodiment is characterized in that it is made of the above-mentioned rubber composition for tires. Since the tread rubber of the present embodiment is made of the above-mentioned rubber composition for tires, by applying it to tires, it is possible to improve the fuel efficiency and wear resistance of the tires. The tread rubber of the present embodiment may be applied to a new tire or a retread tire.
  • the tire of the present embodiment is characterized by including the above-mentioned tread rubber. Since the tire of the present embodiment includes the above-mentioned tread rubber, the tire has improved fuel efficiency and wear resistance.
  • the tire of this embodiment may be obtained by molding an unvulcanized rubber composition and then vulcanizing it, depending on the type of tire to which it is applied, or by molding a semi-vulcanized rubber that has been subjected to a pre-vulcanization process or the like, and then further vulcanizing it.
  • the tire of this embodiment is preferably a pneumatic tire, and the gas to be filled in 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
  • 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).
  • the measurement device used was a spectrophotometer "UV-2450" manufactured by Shimadzu Corporation.
  • the softening point and weight average molecular weight of the resin component were measured by the following methods.
  • the SP value (solubility parameter) of the resin component was calculated according to the Fedors method.
  • Abrasion resistance In accordance with JIS K 6264-2:2005, a Lambourn abrasion tester manufactured by Ueshima Seisakusho was used to attach sandpaper to the grinding wheel, and the amount of abrasion was measured at room temperature with a slip rate of 15%. The evaluation results were indexed, with the reciprocal of the amount of abrasion in Comparative Example 1 set as 100. A larger index value indicates a smaller amount of abrasion and better abrasion resistance.
  • the rubber compositions of Examples 1 to 3 according to the present invention have a greater improvement in abrasion resistance and fuel economy due to the change from non-hydrogenated resin components to hydrogenated resin components, and further, the total improvement in wet performance, abrasion resistance, and fuel economy is greater than that of the rubber compositions of Comparative Examples 6 and 7, which have a high ratio of oil components.

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Abstract

La présente invention aborde le problème consistant à fournir une composition de caoutchouc pour pneu avec laquelle il est possible d'améliorer les performances de faible consommation de carburant et les performances de résistance à l'usure des pneus. Pour résoudre le problème, la composition de caoutchouc pour pneu comprend un composant de type caoutchouc (A), un composant de type huile (B), un composant de type résine (C) et une charge (D), la composition étant caractérisée en ce que : le composant de type caoutchouc (A) comprend un caoutchouc naturel ou un caoutchouc d'isoprène synthétique ; le composant de type résine (C) est au moins partiellement hydrogéné ; et la relation suivante : (C)/(B) (rapport pondéral entre le composant de type résine (C) et le composant de type huile (B)) ≥ 0,5, est satisfaite.
PCT/JP2023/041886 2022-11-25 2023-11-21 Composition de caoutchouc pour pneu, caoutchouc de bande de roulement et pneu WO2024111599A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10204199A (ja) * 1996-11-19 1998-08-04 Mitsubishi Chem Corp 多孔質成形体
WO2021124640A1 (fr) * 2019-12-19 2021-06-24 株式会社ブリヂストン Pneu
JP2021098761A (ja) * 2019-12-19 2021-07-01 株式会社ブリヂストン タイヤ
JP2022121896A (ja) * 2021-02-09 2022-08-22 住友ゴム工業株式会社 ゴム組成物及びタイヤ

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10204199A (ja) * 1996-11-19 1998-08-04 Mitsubishi Chem Corp 多孔質成形体
WO2021124640A1 (fr) * 2019-12-19 2021-06-24 株式会社ブリヂストン Pneu
JP2021098761A (ja) * 2019-12-19 2021-07-01 株式会社ブリヂストン タイヤ
JP2022121896A (ja) * 2021-02-09 2022-08-22 住友ゴム工業株式会社 ゴム組成物及びタイヤ

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