Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C1/00—Tyres characterised by the chemical composition or the physical arrangement or mixture of the composition
  • B60C1/0016—Compositions of the tread
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
  • C08K3/013—Fillers, pigments or reinforcing additives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/34—Silicon-containing compounds
  • C08K3/36—Silica
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L15/00—Compositions of rubber derivatives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L21/00—Compositions of unspecified rubbers
• • 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
• • 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 and a tire rubber composition.
• the objective of the present invention is to provide a rubber composition with improved rolling resistance and grip properties (wet grip properties and/or ice grip properties).
• the present inventors have conducted extensive research to solve the above problems and have completed the present invention. That is, the present invention includes the following preferred embodiments.
• the rubber composition comprises 5 to 30 parts by mass of a modified liquid diene-based polymer (B) having a modifying group represented by the following formula: [2]
• the modified liquid diene polymer (B) contains a structural unit (B-1) derived from butadiene, and the amount of the structural unit (B-1) is 20 to 100 mass% based on the total amount of the modified liquid diene polymer (B).
• the modified liquid diene-based polymer (B) contains a structural unit (B-1) derived from butadiene, and the amount of 1,2-bond units having vinyl groups relative to the total amount of the structural units (B-1) is 0 to 70 mol %.
• the modified liquid diene-based polymer (B) contains a structural unit (B-1) derived from butadiene, and the amount of cis-1,4-bond units in the structural unit (B-1) relative to the total amount of 1,4-bond units is 20 to 60 mol %.
• the modified liquid diene-based polymer (B) contains a structural unit (B-1) derived from butadiene, and the amount of trans-1,4-bond units in the structural unit (B-1) relative to the total amount of 1,4-bond units is 30 to 80 mol %.
• the solid rubber (A) contains 0.1 to 70 mass% of a structural unit derived from styrene based on the total amount of the solid rubber (A).
• the solid rubber (A) is a styrene-butadiene rubber having a weight average molecular weight of 100,000 to 2,500,000.
• the present invention provides a rubber composition that has improved rolling resistance and improved grip (wet grip and/or ice grip).
• the rubber composition of the present invention contains 100 parts by mass of solid rubber (A), 5 to 30 parts by mass of modified liquid diene polymer (B) having a modifying group represented by formula (I) described below, and 30 to 150 parts by mass of filler (C).
• Solid rubber (A) The rubber composition of the present invention contains at least one solid rubber (A).
• Solid rubber (A) refers to rubber that can be handled in a solid state at 20°C.
• the Mooney viscosity ML(1+4) of solid rubber (A) at 100°C is usually 20 to 200.
• solid rubber (A) include natural rubber, styrene butadiene rubber (hereinafter also referred to as "SBR"), butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, ethylene propylene diene rubber, butadiene acrylonitrile copolymer rubber, chloroprene rubber, acrylic rubber, fluororubber, and urethane rubber.
• SBR styrene butadiene rubber
• SBR styrene butadiene rubber
• isoprene rubber butyl rubber
• halogenated butyl rubber ethylene propylene diene rubber
• butadiene acrylonitrile copolymer rubber chloroprene rubber
• acrylic rubber fluor
• the number average molecular weight (Mn) of the solid rubber (A) is preferably 80,000 or more, and more preferably within the range of 100,000 to 3,000,000, from the viewpoint of fully exhibiting the properties of the resulting rubber composition and crosslinked product.
• the number average molecular weight in this specification is the number average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).
• natural rubber examples include TSR (Technically Specified Rubber) such as SMR (TSR produced in Malaysia), SIR (TSR produced in Indonesia), and STR (TSR produced in Thailand), as well as natural rubber commonly used in the tire industry, such as RSS (Ribbed Smoked Sheet), high-purity natural rubber, epoxidized natural rubber, hydroxylated natural rubber, hydrogenated natural rubber, and modified natural rubber such as grafted natural rubber.
• TSR Technically Specified Rubber
• SMR Technically Specified Rubber
• SIR SIR
• STR TSR produced in Thailand
• RSS Rabbed Smoked Sheet
• high-purity natural rubber high-purity natural rubber
• epoxidized natural rubber epoxidized natural rubber
• hydroxylated natural rubber hydroxylated natural rubber
• hydrogenated natural rubber and modified natural rubber
• modified natural rubber such as grafted natural rubber.
• SMR20, STR20, and RSS#3 are preferred in terms of less variation in quality and ease of availability.
• the SBR a typical SBR used for tires can be used.
• the styrene content is preferably 0.1 to 70 mass%, more preferably 5 to 50 mass%, and even more preferably 15 to 35 mass%.
• the vinyl content is preferably 0.1 to 60 mass%, and more preferably 0.1 to 55 mass%.
• the "vinyl content" in the SBR means the proportion of 1,2-bonds contained in the butadiene structural unit, and can be determined by 1 H-NMR measurement.
• the weight average molecular weight (Mw) of SBR is preferably 100,000 to 2,500,000, more preferably 150,000 to 2,000,000, and even more preferably 200,000 to 1,500,000. Within the above range, both processability and mechanical strength can be achieved. Note that the weight average molecular weight in this specification is the polystyrene-equivalent weight average molecular weight determined by gel permeation chromatography (GPC) measurement.
• the glass transition temperature of SBR determined by differential thermal analysis is preferably -95 to 0°C, and more preferably -95 to -5°C. By setting the glass transition temperature within the above range, the viscosity of the SBR can be set within a range that is easy to handle.
• SBR is obtained by copolymerizing styrene and butadiene.
• the manufacturing method of SBR there are no particular limitations on the manufacturing method of SBR, and any of the emulsion polymerization method, solution polymerization method, gas phase polymerization method, and bulk polymerization method can be used, but among these manufacturing methods, the emulsion polymerization method and solution polymerization method are preferred.
• Emulsion-polymerized styrene butadiene rubber (hereinafter also referred to as E-SBR) can be produced by a known or similar normal emulsion polymerization method. For example, it can be obtained by emulsifying and dispersing a given amount of styrene and butadiene monomers in the presence of an emulsifier, and then emulsion-polymerizing them with a radical polymerization initiator.
• Solution-polymerized styrene-butadiene rubber (hereinafter also referred to as S-SBR) can be produced by a conventional solution polymerization method. For example, it can be obtained by polymerizing styrene and butadiene using an active metal capable of anionically polymerizing in a solvent, optionally in the presence of a polar compound.
• Solvents include, for example, aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane; and aromatic hydrocarbons such as benzene and toluene. These solvents are usually preferably used in a range in which the monomer concentration is 1 to 50% by mass.
• active metals capable of anion polymerization include alkali metals such as lithium, sodium, and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium, and barium; and lanthanoid rare earth metals such as lanthanum and neodymium.
• alkali metals and alkaline earth metals are preferred, and alkali metals are more preferred.
• organic alkali metal compounds are more preferably used.
• the organic alkali metal compounds include, for example, organic monolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; polyfunctional organic lithium compounds such as dilithiomethane, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, and 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene, and the like.
• organic lithium compounds are preferred, and organic monolithium compounds are more preferred.
• the amount of the organic alkali metal compound used is determined appropriately according to the molecular weight of the required S-SBR.
• the organic alkali metal compounds can also be used as organic alkali metal amides by reacting them with secondary amines such as dibutylamine, dihexylamine, and dibenzylamine.
• the polar compound there are no particular limitations on the polar compound, so long as it is one that is normally used in anionic polymerization to adjust the microstructure of the butadiene moiety and the distribution of styrene in the copolymer chain without inactivating the reaction.
• examples include ether compounds such as dibutyl ether, tetrahydrofuran, and ethylene glycol diethyl ether; tertiary amines such as tetramethylethylenediamine and trimethylamine; alkali metal alkoxides, and phosphine compounds.
• the temperature of the polymerization reaction is usually in the range of -80 to 150°C, preferably 0 to 100°C, and more preferably 30 to 90°C.
• the polymerization method may be either batchwise or continuous. In order to improve the random copolymerization of styrene and butadiene, it is preferable to continuously or intermittently supply styrene and butadiene to the reaction liquid so that the composition ratio of styrene and butadiene in the polymerization system is within a specific range.
• the polymerization reaction can be stopped by adding an alcohol such as methanol or isopropanol as a polymerization terminator. After the polymerization reaction has been stopped, the solvent can be separated from the polymerization solution by direct drying or steam stripping, and the desired S-SBR can be recovered. Note that the polymerization solution can also be mixed with an extender oil before removing the solvent, and the resulting product can be recovered as oil-extended rubber.
• an alcohol such as methanol or isopropanol
• the solvent can be separated from the polymerization solution by direct drying or steam stripping, and the desired S-SBR can be recovered. Note that the polymerization solution can also be mixed with an extender oil before removing the solvent, and the resulting product can be recovered as oil-extended rubber.
• modified SBR in which functional groups have been introduced may be used as long as the effects of the present invention are not impaired.
• functional groups include amino groups, alkoxysilyl groups, hydroxyl groups, epoxy groups, and carboxyl groups.
• a method for producing modified SBR includes, for example, a method of adding a coupling agent such as tin tetrachloride, tetrachlorosilane, dimethyldichlorosilane, dimethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, 3-aminopropyltriethoxysilane, tetraglycidyl-1,3-bisaminomethylcyclohexane, or 2,4-tolylenediisocyanate that can react with the polymerization active terminals, or a polymerization terminal modifier such as 4,4'-bis(diethylamino)benzophenone or N-vinylpyrrolidone, or other modifiers described in JP 2011-132298 A, before adding a polymerization terminator.
• the position of the polymer where the functional group is introduced may be the polymerization terminal or a side chain of the polymer chain.
• butadiene rubber for example, commercially available butadiene rubber polymerized using Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel; lanthanoid rare earth metal catalysts such as triethylaluminum-organic acid neodymium-Lewis acid; or organic alkali metal compounds as with S-SBR can be used.
• Butadiene rubber polymerized using Ziegler catalysts has a high cis content and is therefore preferred.
• butadiene rubber with an ultra-high cis content obtained using a lanthanoid rare earth metal catalyst may be used.
• the vinyl content of the butadiene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.
• the glass transition temperature varies depending on the vinyl content, but is preferably -40°C or less, and more preferably -50°C or less.
• the weight average molecular weight (Mw) of the butadiene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is within the above range, the processability and mechanical strength are good.
• the butadiene rubber may have a branched structure or polar functional groups by using a polyfunctional modifier, such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an alkoxysilane containing an amino group.
• a polyfunctional modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an alkoxysilane containing an amino group.
• isoprene rubber for example, commercially available isoprene rubber polymerized using Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel; lanthanoid rare earth metal catalysts such as triethylaluminum-organic acid neodymium-Lewis acid; or organic alkali metal compounds as with S-SBR can be used.
• Ziegler catalysts such as titanium tetrahalide-trialkylaluminum, diethylaluminum chloride-cobalt, trialkylaluminum-boron trifluoride-nickel, and diethylaluminum chloride-nickel
• lanthanoid rare earth metal catalysts such as triethylaluminum-organic acid neodymium-Lewis acid
• the vinyl content of the isoprene rubber is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.
• the glass transition temperature varies depending on the vinyl content, but is preferably -20°C or less, and more preferably -30°C or less.
• the weight average molecular weight (Mw) of isoprene rubber is preferably 90,000 to 2,000,000, and more preferably 150,000 to 1,500,000. When Mw is within the above range, the processability and mechanical strength are good.
• the isoprene rubber may have a branched structure or polar functional groups by using a polyfunctional modifier, such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an alkoxysilane containing an amino group.
• a polyfunctional modifier such as tin tetrachloride, silicon tetrachloride, an alkoxysilane having an epoxy group in the molecule, or an alkoxysilane containing an amino group.
• the content of the modified liquid diene polymer (B) per 100 parts by mass of the solid rubber (A) is 5 to 30 parts by mass.
• the dispersion state of the filler (C) in the rubber composition becomes ideal, the rigidity of the resulting composition and crosslinked product is improved, and it is considered that the gripping properties (wet gripping properties and/or ice gripping properties) of tires and the like are improved, thereby improving the steering stability.
• the rolling resistance can be reduced, and the rolling resistance performance is improved.
• the content of the modified liquid diene polymer (B) per 100 parts by mass of the solid rubber (A) is preferably 5 to 25 parts by mass, more preferably 5 to 20 parts by mass, and even more preferably 10 to 20 parts by mass.
• the content of the solid rubber (A) is preferably 20 to 90 mass %, more preferably 25 to 85 mass %, and even more preferably 30 to 80 mass %, based on the total amount of the rubber composition.
• the content of the solid rubber (A) is within the above range, the rubber composition has a good balance between gripping properties and abrasion resistance.
• the rubber composition of the present invention comprises at least one rubber component of formula (I): [Wherein, R 1 represents an alkylene group having 1 to 10 carbon atoms or a phenylene group; R2 represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms; * represents a bond.
• the modified liquid diene polymer (B) has a modifying group represented by the following formula: Hereinafter, the modified liquid diene polymer (B) is also referred to as "polymer (B)".
• Polymer (B) is a polymer that contains structural units derived from conjugated diene monomers, is modified with a modifying group represented by formula (I), and is liquid at room temperature (25°C).
• Conjugated diene monomers include, for example, butadiene, isoprene, ⁇ -farnesene, etc.
• the modified liquid diene polymer may be a homopolymer of one type of conjugated diene monomer, or a copolymer of two or more types of conjugated diene monomers.
• the conjugated diene monomer is preferably at least one selected from the group consisting of butadiene, isoprene, and ⁇ -farnesene, more preferably at least one selected from the group consisting of butadiene and isoprene, and even more preferably butadiene.
• the amount of structural units derived from conjugated diene monomers in polymer (B) is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and even more preferably 95 to 100% by mass, based on the total amount of polymer (B), from the viewpoints of vulcanization reactivity with solid rubber (A) and flowability.
• the conjugated diene monomer preferably contains butadiene, in other words, polymer (B) preferably contains structural units derived from butadiene.
• polymer (B) contains structural units derived from butadiene.
• the amount of structural units derived from butadiene is preferably 20 to 100 mass%, more preferably 30 to 100 mass%, even more preferably 35 to 100 mass%, even more preferably 40 to 100 mass%, and particularly preferably 50 to 100 mass%, based on the total amount of polymer (B).
• the amount of structural units derived from butadiene is equal to or greater than the above lower limit, the modification point is sufficient, and a decrease in productivity of the modified liquid diene-based polymer can be suppressed.
• the amount of the structural unit derived from the conjugated diene monomer and the amount of the structural unit derived from butadiene in the modified liquid diene polymer (B) can be calculated by 1 H-NMR or 13 C-NMR measurement, or from the amount of the conjugated diene monomer or butadiene monomer in the monomer mixture used in producing the modified liquid diene polymer.
• the structural unit derived from butadiene is not particularly limited as long as it is a structural unit derived from the monomer 1,3-butadiene.
• Examples include 1,2-bond units, 1,4-bond units (cis-1,4-bond units and trans-1,4-bond units), and structural units in which a modifying group is bonded to these.
• Each of the 1,2-bond units, cis-1,4-bond units, and trans-1,4-bond units has a vinyl group in the structural unit derived from butadiene.
• Examples of structural units in which a modifying group is bonded to these include structural units obtained by bonding a modifying group to a portion derived from the vinyl group in the 1,2-bond unit, and these structural units do not have a vinyl group.
• the amount of 1,2-bond units having a vinyl group relative to the total amount of 1,4-bond units and 1,2-bond units having a vinyl group in the structural unit (B-1) derived from butadiene is preferably 0 to 70 mol %, more preferably 5 to 70 mol %, and even more preferably 5 to 68 mol % from the viewpoint of handleability (viscosity).
• the amounts of 1,2-bond units having a vinyl group, 1,4-bond units, cis-1,4-bond units, and trans-1,4-bond units described below can be measured by 1 H-NMR and infrared absorption spectroscopy, respectively, and specifically, can be measured by the method described in the Examples.
• the structural unit derived from butadiene preferably includes a structural unit in which a modifying group represented by formula (I) is bonded to a portion derived from a vinyl group in a 1,2-bond unit.
• the amount of the structural unit is preferably 0.1 to 15 mol%, more preferably 1 to 10 mol%, and even more preferably 2 to 9 mol% relative to the total amount of structural units derived from butadiene.
• the amount of the structural unit can be calculated from the molecular weight of each monomer constituting the modified liquid diene polymer, the weight average molecular weight of the modified liquid diene polymer, the approximate value of the number of monomers constituting the modified liquid diene polymer, the approximate value of the number of each bond unit, and the average content of the modifying group determined as described above.
• the amount of 1,4-bond units relative to the total amount of structural units derived from butadiene is preferably 30 to 100 mol%, more preferably 30 to 95 mol%, and even more preferably 32 to 95 mol%, based on the total amount of structural units derived from butadiene, from the viewpoints of handleability and manufacturability of the polymer having the modifying group represented by formula (I).
• the modified liquid diene polymer (B) contains a structural unit (B-1) derived from butadiene, and the amount of cis-1,4-bond units relative to the total amount of 1,4-bond units in the structural unit (B-1) is preferably 20 to 60 mol %, more preferably 30 to 50 mol %.
• the modified liquid diene polymer (B) contains a structural unit (B-1) derived from butadiene, and the amount of trans-1,4-bond units relative to the total amount of 1,4-bond units in the structural unit (B-1) is preferably 30 to 80 mol %, more preferably 40 to 80 mol %, and even more preferably 50 to 70 mol %.
• the weight average molecular weight of polymer (B) is preferably 4,000 to 150,000, more preferably 4,500 to 135,000, even more preferably 4,500 to 125,000, even more preferably 4,500 to 100,000, and particularly preferably 4,500 to 50,000.
• the weight average molecular weight of the liquid diene polymer is the weight average molecular weight in terms of polystyrene determined by measurement using gel permeation chromatography (GPC).
• GPC gel permeation chromatography
• the number average molecular weight of the modified liquid diene polymer is preferably 200 to 150,000, more preferably 900 to 135,000, even more preferably 2,000 to 125,000, even more preferably 2,600 to 100,000, particularly preferably 2,600 to 50,000, and especially preferably 3,800 to 50,000, from the viewpoint of handleability such as threading.
• the number average molecular weight of the liquid diene polymer can also be measured by gel permeation chromatography (GPC).
• the molecular weight distribution (Mw/Mn) of polymer (B) is preferably 1.0 to 20.0, more preferably 1.0 to 15.0, even more preferably 1.0 to 10.0, even more preferably 1.0 to 5.0, particularly preferably 1.0 to 2.0, particularly preferably 1.0 to 1.5, and most preferably 1.0 to 1.3. If Mw/Mn is within the above range, the viscosity of the resulting polymer (B) will vary less, which is more preferable.
• the molecular weight distribution (Mw/Mn) refers to the ratio of the weight average molecular weight (Mw)/number average molecular weight (Mn) calculated in terms of standard polystyrene, determined by GPC measurement.
• the modified liquid diene polymer (B) has the formula (I): [Wherein, R 1 represents an alkylene group having 1 to 10 carbon atoms or a phenylene group; R2 represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms; * represents a bond.
• the polymer (B) has a modifying group represented by the formula (I).
• the modifying group is hereinafter also referred to as a modifying group (I).
• the polymer (B) may be modified with one type of modifying group represented by the formula (I), or may be modified with two or more types of modifying groups represented by the formula (I).
• R 1 represents an alkylene group having 1 to 10 carbon atoms or a phenylene group.
• alkylene groups having 1 to 10 carbon atoms include methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, and decylene.
• the alkylene group may be linear or branched.
• the alkylene group preferably has 1 to 10 carbon atoms, and more preferably 2 to 6 carbon atoms.
• the phenylene group is a divalent group having two bonds on the phenyl ring, and the two bonds may be in the ortho, meta, or para position.
• the phenylene group may be a group in which at least one hydrogen atom bonded to a carbon atom on the phenyl ring is substituted with an alkyl group having 1 to 4 carbon atoms.
• R 1 in the formula (I) is preferably an alkylene group having 2 to 6 carbon atoms.
• R2 represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms.
• the alkyl group having 1 to 2 carbon atoms is a methyl group or an ethyl group.
• R2 in formula (I) is preferably a hydrogen atom.
• the * in formula (I) represents a bond.
• the bond is preferably bonded to a structural unit derived from a conjugated diene monomer of the modified liquid diene polymer (B), more preferably to a portion derived from a side chain vinyl group of a structural unit derived from a conjugated diene monomer, and even more preferably to a portion derived from a side chain vinyl group of a 1,2-bond unit derived from butadiene.
• the bond is bonded to a structural unit derived from butadiene, more preferably to a portion derived from a vinyl group of a 1,4-bond unit or a portion derived from a vinyl group of a 1,2-bond unit, even more preferably to a portion derived from a vinyl group of a 1,2-bond unit, and even more preferably to a portion derived from a side chain vinyl group of a 1,2-bond unit. Therefore, the modifying group represented by formula (I) is preferably included in the side chain of the polymer (B).
• the structure of the modifying group represented by formula (I) can be analyzed, for example, by structural analysis of the resulting polymer using NMR analysis, or from the structure of the modifying compound used in synthesizing the polymer.
• the average content of the modifying group represented by formula (I) is preferably 0.5 to 10, more preferably 0.5 to 7, even more preferably 0.5 to 5, still more preferably 1 to 5, and particularly preferably 1 to 4.5 per molecule of the modified liquid diene polymer from the viewpoint of improving the dispersibility of the filler (C) in the rubber composition, the wet grip property, and the ice grip property, and from the viewpoint of suppressing bleed-out of the polymer (B), etc.
• the average content of the modifying group represented by formula (I) can be determined by 1 H-NMR.
• the modified liquid diene polymer (B) is a polymer containing structural units derived from a conjugated diene monomer, and may be a homopolymer of one type of conjugated diene monomer, a copolymer of two or more types of conjugated diene monomer, or a copolymer of one or more types of conjugated diene monomer and one or more types of other monomers (e.g., aromatic vinyl compounds).
• the polymer (B) may have only structural units derived from one or more types of conjugated diene monomers (e.g., butadiene), or may have structural units derived from aromatic vinyl compounds in addition to the structural units derived from the conjugated diene monomer.
• the polymer (B) is a copolymer, it may be a random copolymer or a block copolymer.
• the polymer (B) preferably does not have a hydroxyl group at its terminal. Whether or not the polymer has a hydroxyl group at its terminal can be confirmed by the neutralization titration method of the hydroxyl value according to JIS K 0070-1992, infrared absorption spectrum (IR), or 1H -NMR.
• the above-mentioned polymer (B) has the effect of improving the dispersibility of the filler (C) in the rubber composition of the present invention, and therefore can improve the rigidity, rolling resistance, wet grip properties, and ice grip properties of the rubber composition or its crosslinked product. These properties are also affected by the type and amount of filler contained in the rubber composition and the molecular weight of the polymer (B), but these may be adjusted to a desired range for various purposes required of the rubber composition.
• the rubber composition of the present invention can provide a rubber composition that has improved rigidity, rolling resistance, wet grip properties, and ice grip properties compared to a rubber composition that contains a liquid diene-based polymer that does not fall under the modified liquid diene-based polymer of the present invention and has a similar weight average molecular weight and contains a similar amount of filler.
• the method for producing the modified liquid diene polymer is not particularly limited. For example, it is preferable to produce an unmodified liquid diene polymer by polymerizing butadiene and other monomers copolymerizable with butadiene, which are included as necessary, by, for example, a solution polymerization method, and then reacting the unmodified liquid polymer with a modifying compound to produce the modified liquid diene polymer.
• a monomer containing butadiene is polymerized in a solvent using a Ziegler catalyst, a metallocene catalyst, or an anionically polymerizable active metal or active metal compound, if necessary in the presence of a polar compound.
• Solvents include, for example, aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, and isooctane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane; and aromatic hydrocarbons such as benzene, toluene, and xylene.
• aliphatic hydrocarbons such as n-butane, n-pentane, isopentane, n-hexane, n-heptane, and isooctane
• alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane
• aromatic hydrocarbons such as benzene, toluene, and xylene.
• active metals capable of anion polymerization include alkali metals such as lithium, sodium, and potassium; alkaline earth metals such as beryllium, magnesium, calcium, strontium, and barium; and lanthanoid rare earth metals such as lanthanum and neodymium.
• alkali metals and alkaline earth metals are preferred, and alkali metals are more preferred.
• an organic alkali metal compound is preferred.
• the organic alkali metal compound include organic monolithium compounds such as methyllithium, ethyllithium, n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; polyfunctional organic lithium compounds such as dilithiomethane, dilithionaphthalene, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, and 1,3,5-trilithiobenzene; sodium naphthalene, potassium naphthalene, and the like.
• organic lithium compounds are preferred, and organic monolithium compounds are more preferred.
• the amount of organic alkali metal compound used can be set appropriately depending on the desired melt viscosity, molecular weight, etc. of the modified liquid diene polymer, but it is usually used in an amount of 0.01 to 3 parts by mass per 100 parts by mass of total monomers.
• organic alkali metal compounds can also be reacted with secondary amines such as dibutylamine, dihexylamine, and dibenzylamine to be used as organic alkali metal amides.
• secondary amines such as dibutylamine, dihexylamine, and dibenzylamine
• polar compounds are usually used to adjust the microstructure (e.g., vinyl content) of the unmodified liquid diene polymer without deactivating the reaction.
• polar compounds include ether compounds such as dibutyl ether, tetrahydrofuran, and ethylene glycol diethyl ether; tertiary amines such as tetramethylethylenediamine and trimethylamine; alkali metal alkoxides, and phosphine compounds.
• Polar compounds are usually used in an amount of 0.01 to 1,000 moles per mole of the organic alkali metal compound.
• the temperature for solution polymerization is usually in the range of -80 to 150°C, preferably in the range of 0 to 100°C, and more preferably in the range of 10 to 90°C.
• the polymerization method may be either batch or continuous.
• the polymerization reaction can be stopped by adding a polymerization terminator.
• polymerization terminators include alcohols such as methanol and isopropanol.
• the resulting polymerization reaction liquid can be poured into a poor solvent such as methanol to precipitate the unmodified liquid diene polymer, or the polymerization reaction liquid can be washed with water, separated, and then dried to isolate the unmodified liquid diene polymer.
• the unmodified liquid diene polymer thus obtained may be modified by reacting it as it is (without hydrogenation) with a compound that provides the functional group represented by formula (I), or it may be modified by reacting it with a compound that provides the functional group represented by formula (I) after hydrogenating at least a portion of the unsaturated bonds contained in the unmodified liquid diene polymer thus obtained.
• the unmodified liquid diene polymer is not modified with a functional group such as a hydroxyl group.
• a functional group such as a hydroxyl group.
• the stability of the resulting modified liquid diene polymer tends to be superior.
• the interaction (e.g., reactivity) of the functional group represented by formula (I) contained in the modified liquid diene polymer with a filler (e.g., silica) tends to be superior.
• the unmodified liquid diene-based polymer may be, for example, a compound represented by the formula (II): [ R1 and R2 in formula (II) are the same as R1 and R2 in formula (I), respectively]
• a modified liquid diene polymer modified with a modifying group represented by the above formula (I) can be produced by reacting the unmodified liquid diene polymer with one type of compound (II) or two or more types of compound (II).
• the mercapto group (-SH) of compound (II) undergoes a radical addition reaction with the carbon-carbon unsaturated bond contained in the unmodified liquid diene polymer, thereby introducing the functional group represented by the above formula (I) into the polymer.
• this radical addition reaction it is presumed that the radical addition reaction occurs preferentially with the carbon-carbon unsaturated bond in the side chain contained in the butadiene unit having a 1,2-bond in the unmodified liquid diene polymer.
• R1 and R2 in the above formula (II) are the same as the definitions and specific examples of R1 and R2 in the above formula (I).
• Specific compounds represented by the above formula (II) include 2-aminoethanethiol, 2-methylaminoethanethiol, 2-ethylaminoethanethiol, 2-dimethylaminoethanethiol, 2-diethylaminoethanethiol, p-aminothiophenol, p-methylaminothiophenol, and p-dimethylaminothiophenol.
• the method of adding the compound represented by formula (II) to the unmodified liquid diene polymer is not particularly limited, and for example, a method can be adopted in which the compound represented by formula (II) and, if necessary, a radical catalyst are added to the unmodified liquid diene polymer, and the mixture is heated in the presence or absence of an organic solvent.
• a radical catalyst there is no particular limit to the radical generator used, and commercially available organic peroxides, azo compounds, hydrogen peroxide, etc. can be used.
• organic peroxides include, for example, methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, acetylacetone peroxide, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, and 2,2-bis(t-butylperoxy).
• the above azo compounds include, for example, 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), 2,2'-azobis(2-(2-imidazolin-2-yl)propane), 2,2' -Azobis(2,4,4-trimethylpentane), 2,2'-azobis(2-methylpropane), 2,2'-azobis(2-hydroxymethylpropiononitrile), 4,4'-azobis(4-cyanovaleric acid), dimethyl 2,2'-azobis(2-methylpropionate), 2-cyano-2-propylazoformamide, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, etc.
• the organic solvents used in the above method generally include hydrocarbon solvents and halogenated hydrocarbon solvents.
• hydrocarbon solvents such as n-butane, n-hexane, n-heptane, cyclohexane, benzene, toluene, and xylene are preferred.
• an anti-aging agent may be added to suppress side reactions.
• Preferred antioxidants for use in this case include, for example, 2,6-di-t-butyl-4-methylphenol (BHT), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol) (AO-40), 3,9-bis[1,1-dimethyl-2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl) propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (AO-80), 2,4-bis[(octylthio)methyl]-6-methylphenol (Irganox 1520L), 2,4-bis[(dodecylthio)methyl]-6-methylphenol (Irganox 1726), 2-[1-(2-hydroxy-3,5-di-t-pentylpheny
• the amount of antioxidant added is preferably 0 to 10 parts by mass, and more preferably 0 to 5 parts by mass, per 100 parts by mass of unmodified liquid diene polymer.
• the position at which the functional group is introduced may be the end of the polymer chain or a side chain of the polymer chain, but from the viewpoint of easily introducing multiple functional groups, a side chain of the polymer chain is preferable.
• the functional group may be contained alone or in combination with two or more types.
• the modified liquid diene polymer may be modified with one type of modifying compound, or may be modified with two or more types of modifying compounds.
• the mixing ratio of the unmodified liquid diene polymer and the modified compound may be appropriately set so that the average number of functional groups per molecule of the modified liquid diene polymer is the desired value, but it is preferable to mix the unmodified liquid diene polymer and the modified compound (e.g., compound (II)) so that the mass ratio (unmodified liquid diene polymer/modified compound) is 0.3 to 50.
• the modified compound e.g., compound (II)
• a method for producing a modified liquid diene polymer having specific properties it is effective to carry out a radical addition reaction of a modified compound (e.g., compound (II)) at an appropriate reaction temperature for a sufficient reaction time.
• a modified compound e.g., compound (II)
• the temperature in the reaction of adding a modified compound to an unmodified liquid diene polymer is preferably 10 to 200°C, more preferably 50°C to 180°C.
• the reaction time is preferably 1 to 200 hours, more preferably 1 to 100 hours, and even more preferably 1 to 50 hours.
• the rubber composition of the present invention contains at least one filler (C).
• the filler (C) include inorganic fillers such as carbon black, silica, clay, mica, calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, titanium oxide, glass fiber, fibrous filler, and glass balloons; and organic fillers such as resin particles, wood powder, and cork powder.
• inorganic fillers such as carbon black, silica, clay, mica, calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, titanium oxide, glass fiber, fibrous filler, and glass balloons
• organic fillers such as resin particles, wood powder, and cork powder.
• carbon black and silica are preferred among the above fillers (C).
• These fillers (C) may be used alone or in combination of two or more.
• the filler (C) at least one selected from the group consisting of carbon black and silica is preferred.
• carbon black examples include furnace black, channel black, thermal black, acetylene black, and ketjen black.
• furnace black is preferred from the viewpoint of improving the crosslinking rate and mechanical strength.
• carbon blacks may be used alone or in combination of two or more types.
• the average particle size of carbon black is preferably 5 to 100 nm, more preferably 5 to 80 nm, even more preferably 5 to 70 nm, and even more preferably 5 to 25 nm, from the viewpoint of improving dispersibility, mechanical strength, hardness, etc.
• the average particle size of carbon black can be determined by measuring the particle diameter using a transmission electron microscope and calculating the average value.
• furnace black products include, for example, "Diablack” manufactured by Mitsubishi Chemical Corporation and “Seat” manufactured by Tokai Carbon Co., Ltd.
• acetylene black products include, for example, “Denka Black” manufactured by Denki Kagaku Kogyo Co., Ltd.
• ketjen black products include, for example, "ECP600JD” manufactured by Lion Corporation.
• the carbon black may be subjected to an acid treatment with nitric acid, sulfuric acid, hydrochloric acid or a mixed acid thereof, or a surface oxidation treatment by heat treatment in the presence of air.
• the carbon black may be subjected to a heat treatment at 2,000 to 3,000° C. in the presence of a graphitization catalyst.
• boron As the graphitization catalyst, boron, boron oxides (e.g., B 2 O 2 , B 2 O 3 , B 4 O 3 , B 4 O 5 , etc.), boron oxoacids (e.g., orthoboric acid, metaboric acid, tetraboric acid, etc.) and salts thereof, boron carbides (e.g., B 4 C, B 6 C, etc.), boron nitride (BN), and other boron compounds are preferably used.
• boron carbides e.g., B 4 C, B 6 C, etc.
• BN boron nitride
• Carbon black can also be used after adjusting the particle size by grinding or other methods.
• High-speed rotary grinders hammer mills, pin mills, cage mills), various ball mills (rolling mills, vibrating mills, planetary mills), stirring mills (bead mills, attritors, flow-tube mills, annular mills), etc. can be used to grind carbon black.
• silica examples include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, and aluminum silicate.
• wet silica is preferred from the viewpoint of further improving processability, mechanical strength, and abrasion resistance.
• These silicas may be used alone or in combination of two or more types.
• the average particle size of silica is preferably 0.5 to 200 nm, more preferably 5 to 150 nm, even more preferably 10 to 100 nm, and even more preferably 10 to 50 nm.
• the average particle size of silica can be determined by measuring the diameter of the particles using a transmission electron microscope and calculating the average value.
• the rubber composition preferably contains carbon black and/or silica as the filler (C), and more preferably contains silica.
• the rubber composition also preferably contains carbon black having an average particle size of 5 to 100 nm and/or silica having an average particle size of 0.5 to 200 nm.
• the content of the filler (C) relative to 100 parts by mass of the solid rubber (A) is 30 to 150 parts by mass.
• the content of the filler (C) is 30% by mass or more, it is preferable from the viewpoint of the wear resistance of the rubber composition, and when it is 150% by mass or less, it is preferable from the viewpoint of the gripping property of the rubber composition.
• the content of the filler (C) is preferably 33 to 140 parts by mass, more preferably 35 to 130 parts by mass, even more preferably 40 to 120 parts by mass, even more preferably 50 to 110 parts by mass, and extremely preferably 60 to 100 parts by mass.
• the amount of filler other than silica and carbon black in filler (C) is not particularly limited, but may be, for example, 0 to 120 parts by mass, preferably 0 to 90 parts by mass, more preferably 0 to 80 parts by mass, and even more preferably 0 to 70 parts by mass, per 100 parts by mass of solid rubber (A).
• the total mass of the solid rubber (A), modified liquid diene polymer (B), and filler (C) contained in the rubber composition is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 85 to 100% by mass, based on the total amount of the rubber composition, from the viewpoint of the stability of the rubber composition.
• the rubber composition may further contain a crosslinking agent (D) to crosslink the rubber.
• a crosslinking agent (D) include sulfur, sulfur compounds, oxygen, organic peroxides, phenolic resins, amino resins, quinones and quinone dioxime derivatives, halogen compounds, aldehyde compounds, alcohol compounds, epoxy compounds, metal halides and organometallic halides, and silane compounds.
• sulfur compounds include morpholine disulfide and alkylphenol disulfides.
• organic peroxides examples include cyclohexanone peroxide, methyl acetoacetate peroxide, t-butyl peroxyisobutyrate, t-butyl peroxybenzoate, benzoyl peroxide, lauroyl peroxide, dicumyl peroxide, di-t-butyl peroxide, and 1,3-bis(t-butylperoxyisopropyl)benzene.
• crosslinking agents (D) may be used alone or in combination of two or more.
• the crosslinking agent (D) is preferably contained in an amount of 0.1 to 10 parts by mass, more preferably 0.5 to 10 parts by mass, and even more preferably 0.8 to 5 parts by mass, per 100 parts by mass of the solid rubber (A).
• the rubber composition may further contain a vulcanization accelerator (E).
• a vulcanization accelerator (E) examples include guanidine compounds, sulfenamide compounds, thiazole compounds, thiuram compounds, thiourea compounds, dithiocarbamic acid compounds, aldehyde-amine compounds, aldehyde-ammonia compounds, imidazoline compounds, and xanthate compounds. These vulcanization accelerators (E) may be used alone or in combination of two or more.
• the vulcanization accelerator (E) is preferably contained in an amount of 0.1 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the solid rubber (A).
• the rubber composition may further contain a vulcanization aid (F).
• a vulcanization aid examples include fatty acids such as stearic acid, metal oxides such as zinc oxide, and fatty acid metal salts such as zinc stearate. These vulcanization aids (F) may be used alone or in combination of two or more types.
• the amount of the vulcanization aid (F) is preferably 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass, per 100 parts by mass of the solid rubber (A).
• the rubber composition contains silica as the filler (C)
• the rubber composition further contains a silane coupling agent.
• silane coupling agents include sulfide compounds, mercapto compounds, vinyl compounds, amino compounds, glycidoxy compounds, nitro compounds, and chloro compounds.
• Sulfide compounds include, for example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-trimethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, and 3-trimethoxysilylpropyl-N,N-dimethylsilyl.
• thiocarbamoyl tetrasulfide 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-trimethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl benzothiazole tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, and 3-octanoylthio-1-propyltriethoxysilane.
• Examples of mercapto compounds include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane.
• vinyl compounds examples include vinyltriethoxysilane and vinyltrimethoxysilane.
• amino compounds include 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-(2-aminoethyl)aminopropyltrimethoxysilane.
• glycidoxy compounds include gamma-glycidoxypropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, and gamma-glycidoxypropylmethyldimethoxysilane.
• nitro compounds include 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane.
• chloro-based compounds examples include 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane.
• Other compounds include, for example, octyltriethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, and hexadecyltrimethoxysilane.
• silane coupling agents may be used alone or in combination of two or more.
• silane coupling agents bis(3-triethoxysilylpropyl) disulfide, bis(3-triethoxysilylpropyl) tetrasulfide, and 3-mercaptopropyltrimethoxysilane are preferred from the viewpoints of the large additive effect and cost.
• the amount of the silane coupling agent is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and even more preferably 1 to 15 parts by mass, per 100 parts by mass of silica. If the content of the silane coupling agent is within the above range, dispersibility, coupling effect, reinforcement, and abrasion resistance are improved.
• the rubber composition according to a preferred embodiment of the present invention contains at least one resin.
• the resin may be a synthetic resin or a natural resin. These resins may be used alone or in combination of two or more types.
• Synthetic resins include petroleum-based resins, and oligomers obtained by polymerizing raw materials consisting of C5 fractions, C9 fractions, refined components of C5 fractions, refined components of C9 fractions, or mixtures of these fractions or refined components can be used. Oligomers obtained in this manner that have been modified by hydrogenation or the like can also be used.
• C5 fractions include cyclopentadiene, dicyclopentadiene, isoprene, 1,3-pentadiene, 2-methyl-1-butene, 2-methyl-2-butene, 1-pentene, 2-pentene, and cyclopentene.
• C9 fractions include styrene, allylbenzene, ⁇ -methylstyrene, vinyltoluene, ⁇ -methylstyrene, and indene.
• alkylphenol resins and xylene resins can also be used.
• a rosin-based resin or a terpene-based resin can be used as the natural resin.
• the rosin-based resin is a resin obtained from pine trees, and the main component is a mixture of abietic acid and its isomers. It also includes those modified by esterification, polymerization, hydrogenation, etc. Examples of unmodified rosin-based resins include tall rosin, gum rosin, and wood rosin. It also includes polymerized rosin, disproportionated rosin, hydrogenated rosin, maleic acid-modified rosin, fumaric acid-modified rosin, and those modified by esterification, hydrogenation, etc.
• the terpene-based resin is an oligomer obtained by polymerizing a raw material containing a terpene-based monomer. It also includes oligomers modified by hydrogenation, etc. of this oligomer.
• the terpene monomer include ⁇ -pinene, ⁇ -pinene, dipentene, limonene, myrcene, alloocimene, ocimene, ⁇ -phellandrein, ⁇ -terpinene, ⁇ -terpinene, terpinolene, 1,8-cineole, 1,4-cineole, ⁇ -terpineol, ⁇ -terpineol, ⁇ -terpineol, sabinene, paramentadienes, carenes, etc., which have a monoterpene, sesquiterpene, diterpene, etc., skeleton.
• coumarone monomers such as benzofuran (C 8 H 6 O), vinyl aromatic compounds, phenol monomers, etc., which are copolymerizable with the terpene monomer, may be included, and the resulting oligomers may also be modified by hydrogenation or the like.
• the amount of resin in the rubber composition is preferably 0 to 400 parts by mass, more preferably 0 to 200 parts by mass, and even more preferably 0 to 150 parts by mass, per 100 parts by mass of solid rubber.
• the rubber composition contains a resin, it is possible to impart adhesion to the rubber composition, improve processability, and improve the slipperiness of the rubber.
• the rubber composition may contain silicone oil, aromatic oil, TDAE (Treated Distilled Aromatic Extracts), MES (Mild Extracted Solvates), RAE (Residual Aromatic Extracts), process oils such as paraffin oil and naphthene oil, and resin components such as coumarone-indene resins as softeners as necessary for the purpose of improving processability, fluidity, etc., within the scope of not impairing the effects of the present invention.
• the rubber composition contains the above process oil as a softener, the content is preferably less than 50 parts by mass per 100 parts by mass of the solid rubber (A).
• the rubber composition may contain additives such as antiaging agents, waxes, antioxidants, lubricants, light stabilizers, scorch inhibitors, processing aids, colorants such as pigments and dyes, flame retardants, antistatic agents, matting agents, antiblocking agents, UV absorbers, release agents, foaming agents, antibacterial agents, antifungal agents, and fragrances, as necessary, to improve weather resistance, heat resistance, oxidation resistance, and the like, within a range that does not impair the effects of the present invention.
• antioxidants include hindered phenol compounds, phosphorus compounds, lactone compounds, and hydroxyl compounds.
• antiaging agents include amine-ketone compounds, imidazole compounds, amine compounds, phenol compounds, sulfur compounds, and phosphorus compounds. These additives may be used alone or in combination of two or more.
• the method for producing the rubber composition is not particularly limited as long as the above-mentioned components can be mixed uniformly.
• Examples of the apparatus used for producing the rubber composition include tangential or intermeshing internal mixers such as kneader-ruder, Brabender, Banbury mixer, and internal mixer, single screw extruder, twin screw extruder, mixing roll, and roller.
• the rubber composition can usually be produced at a temperature range of 70 to 270°C.
• a crosslinked product can be obtained by crosslinking the above rubber composition.
• the crosslinking conditions of the rubber composition can be appropriately set depending on the application, etc. For example, when sulfur or a sulfur compound is used as a crosslinking agent and the rubber composition is placed in a mold and heated to crosslink (vulcanize), the crosslinking temperature is usually 120 to 200°C and the pressure condition is usually 0.5 to 2.0 MPa, and crosslinking (vulcanization) can be performed.
• the extraction rate of the modified liquid diene polymer (B) from the crosslinked product is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less.
• the extraction rate can be calculated by immersing 2 g of the crosslinked product in 400 mL of toluene at 23°C for 48 hours and calculating the amount of modified liquid diene polymer (B) extracted into the toluene.
• the rubber composition and the cross-linked product of the rubber composition can also be used as at least a part of a tire.
• the tire obtained in this manner has excellent rolling resistance performance, good abrasion resistance, and excellent gripping properties (wet gripping properties and/or ice gripping properties) because the filler (C) is ideally dispersed (e.g., the Payne effect is sufficiently reduced).
• the bleed-out of the modified liquid diene polymer can be suppressed, and the stability is excellent.
• the present invention also provides a tire rubber composition containing the rubber composition of the present invention and/or the cross-linked product of the rubber composition.
• tire parts in which the above rubber composition and the cross-linked product of the rubber composition can be used include treads (cap treads, under treads), sidewalls, rubber reinforcing layers for run-flat tires (liners, etc.), rim cushions, bead fillers, bead insulation, bead apexes, clinch apexes, belts, belt cushions, breakers, breaker cushions, chafers, chafer pads, strip apexes, etc.
• tires for which the rubber composition and the crosslinked product of the rubber composition can be used include pneumatic tires and non-pneumatic tires, among which pneumatic tires are preferred.
• the tire can be suitably used as a summer tire or a winter tire (such as a studless tire, a snow tire, or a studded tire).
• the tire can be used as a passenger car tire, a large passenger car tire, a large SUV tire, a heavy-duty tire for trucks and buses, a light truck tire, a two-wheeled vehicle tire, a run-flat tire, a racing tire (high-performance tire), or the like.
• the rubber composition and the cross-linked product of the rubber composition can be used for purposes other than tires, such as packing, sheet members, hoses, belts, rubber-coated fabrics, footwear, and adhesives.
• the weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw/Mn) of the modified liquid diene polymer were determined in terms of standard polystyrene by gel permeation chromatography (GPC) using the following measuring device and conditions: ⁇ Apparatus: Tosoh Corporation's GPC device "HLC-8320GPC” Separation column: Tosoh Corporation "TSKgel Super HZ4000 x 2" Eluent: Tetrahydrofuran Eluent flow rate: 0.35 mL/min Sample concentration: 5 mg/10 mL Column temperature: 40°C
• the peak integral values of the peak derived from the 1,2-bond and the peaks derived from the 1,2-bond and the 1,4-bond were determined in the 1 H-NMR spectrum obtained in Measurement 1.
• the abundance ratios (X, Y, Z) (molar ratio) of the peak derived from the 1,2-bond, the peak derived from the 1,4-bond, and the peak derived from 2-aminoethanethiol were calculated from the ratio of the peak integral values obtained in Measurement 1.
• the ratio (mol%) of the 1,2-bond unit having a vinyl group to the total amount of the structural units derived from butadiene in the modified liquid diene polymer was calculated.
• melt viscosity of the unmodified liquid diene polymer at 38° C. was measured by a Brookfield viscometer (manufactured by BROOKFIELD ENGINEERING LABS. INC.).
• the weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw/Mn), proportion of cis-1,4-bond units and proportion of trans-1,4-bond units in 1,4-bond units, and melt viscosity of the unmodified liquid diene-based polymers 1 and 2 obtained as described above were measured according to the methods described above. The results are shown in Table 1.
• the amount of structural units derived from butadiene in the unmodified polymers 1 and 2 was 100% by mass based on the total amount of the polymer.
• proportion (a) is the proportion (mol %) of each bond unit relative to the total amount of structural units derived from butadiene in the modified liquid diene polymer
• proportion (b) is the proportion (mol %) of each bond unit relative to the total amount of 1,4-bond units in the modified liquid diene polymer.
• Solution-polymerized styrene-butadiene rubber HPR355 (manufactured by ENEOS Materials Corporation, alkoxysilyl groups introduced at the ends, styrene content 28% by mass, vinyl content 56% by mass)
• STR20 Natural rubber produced in Thailand Butadiene rubber: BR01 (manufactured by ENEOS Materials Corporation, Mw: 550,000, cis content: 95% by mass)
• Silica-silane coupling agent > Silica: ULTRASIL7000GR (manufactured by Evonik Japan, wet silica, average particle size 14 nm) Silane coupling agent: Si-75 (manufactured by Evonik Japan)
• Zinc oxide ZnO (manufactured by Sakai Chemical Industry Co., Ltd.) Stearic acid: Lunac S-20 (Kao Corporation) Wax: Suntite S (Seiko Chemical Co., Ltd.) Antioxidant: Norak 6C (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)
• Vulcanizing agent Insoluble sulfur Myucron OT-20 (manufactured by Shikoku Chemical Industry Co., Ltd.)
• Vulcanization accelerator 1 Noccela CZ (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)
• Vulcanization accelerator 2 Noccelaer D (manufactured by Ouchi Shinko Chemical Industry Co., Ltd.)
• Examples 1 to 10 and Comparative Examples 1 to 6 Production of Rubber Compositions
• the solid rubber, polymer, filler, plasticizer, silane coupling agent, zinc oxide, stearic acid, wax and antioxidant were each charged into an internal Banbury mixer and kneaded for 6 to 8 minutes so that the starting temperature was 60° C. and the resin temperature was 145 to 160° C., and then the mixture was taken out of the mixer and cooled to room temperature. Next, this mixture was again charged into the internal Banbury mixer and kneaded for 4 to 6 minutes so that the starting temperature was 90° C.
• the obtained rubber composition was press molded (150-170°C, 30-50 minutes) to prepare a vulcanized rubber sheet (thickness 2 mm), and the physical properties were evaluated based on the following methods.
• the measurement methods for each evaluation are as follows. The obtained evaluation results are shown in Tables 3 to 5.
• ⁇ Rolling resistance performance> A test piece measuring 40 mm long x 5 mm wide was cut out from the sheet of the rubber composition prepared in the examples and comparative examples, and tan ⁇ was measured using a dynamic viscoelasticity measuring device manufactured by GABO under the conditions of a measurement temperature of 60 ° C., a frequency of 10 Hz, a static strain of 10%, and a dynamic strain of 2%, and the reciprocal of the obtained result was used as an index of rolling resistance performance.
• Example 1 the reciprocal of tan ⁇ of Examples 1 to 3 is Comparative Example 1
• Example 4 is Comparative Example 2
• Examples 5 to 6 are Comparative Example 3
• Examples 7 to 8 are Comparative Example 4
• Example 9 is Comparative Example 5
• Example 10 is Comparative Example 6 is shown in Tables 3 to 5 as rolling resistance performance when the reciprocal of tan ⁇ is set to 100. The higher the value, the better the rolling resistance performance of the rubber composition.
• the rubber composition of the present invention has improved rolling resistance and grip performance (wet grip performance and/or ice grip performance) compared to a rubber composition containing a diene polymer of a similar molecular weight and a similar amount of filler. In addition, improved rigidity and bleed-out suppression effects were also obtained.

Landscapes

• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=93851870

Family Applications (1)

Country Status (5)

Citations (6)

• 2024
  • 2024-06-04 WO PCT/JP2024/020376 patent/WO2024257653A1/ja not_active Ceased
  • 2024-06-04 EP EP24823272.0A patent/EP4729575A1/en active Pending
  • 2024-06-04 CN CN202480039207.1A patent/CN121311538A/zh active Pending
  • 2024-06-04 JP JP2025527852A patent/JPWO2024257653A1/ja active Pending
  • 2024-06-14 TW TW113122046A patent/TW202506749A/zh unknown

Patent Citations (6)

Also Published As

Similar Documents

Legal Events