Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F136/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
  • C08F136/02—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
  • C08F136/04—Homopolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
  • C08F136/06—Butadiene
• • 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
• • 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
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F236/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds
  • C08F236/02—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds
  • C08F236/04—Copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds the radical having only two carbon-to-carbon double bonds conjugated
  • C08F236/08—Isoprene
• • 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
  • 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
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group

Definitions

• the present invention relates to a rubber composition and a tire.
• the second monomer component is introduced into the network structure formed by polymerizing and cross-linking the first monomer component.
• the semi-interpenetrating network hydrogel or the interpenetrating network hydrogel obtained by polymerizing the second monomer component and optionally cross-linking 10 mol% or more of the first monomer component has a charge. It is an unsaturated monomer, and 60 mol% or more of the second monomer component is an electrically neutral unsaturated monomer, and the amount of the first monomer component: the amount of the second monomer component is 1 in molar ratio.
• High-strength gels have been developed by hydrogels or interpenetrating networked hydrogels, ie double network gels.
• the cut resistance of the rubber component made of natural rubber and / or synthetic isoprene rubber is improved by adding syndiotactic 1,2-polybutadiene. I also found that I could do it.
• the gist structure of the present invention for solving the above problems is as follows.
• the rubber composition of the present invention contains a rubber component composed of natural rubber and / or synthetic isoprene rubber, and syndiotactic 1,2-polybutadiene, and the syndiotactic 1,2-polybutadiene has a crystal content of 7 It is characterized in that it is ⁇ 40 J / g and the number average molecular weight is 6.5 ⁇ 10 4 or more.
• fuel efficiency, wear resistance and cut resistance when applied to a tire can be achieved at a higher level.
• the content of the syndiotactic 1,2-polybutadiene is preferably 10 to 30 parts by mass with respect to 100 parts by mass of the rubber component. In this case, fuel efficiency, wear resistance and cut resistance when applied to a tire can be achieved at a higher level.
• the melting point of the syndiotactic 1,2-polybutadiene is preferably 100 to 180 ° C. In this case, fuel efficiency, wear resistance and cut resistance when applied to a tire can be achieved at a higher level.
• the 1,2-bond content of the syndiotactic 1,2-polybutadiene is preferably 80% by mass or more. In this case, fuel efficiency, wear resistance and cut resistance when applied to a tire can be achieved at a higher level.
• the rubber composition of the present invention preferably further contains a filler, more preferably the filler contains at least carbon black, and the content of the carbon black is 10 with respect to 100 parts by mass of the rubber component. It is more preferably to 70 parts by mass. In this case, the wear resistance and cut resistance of the rubber composition can be further improved.
• a rubber composition containing carbon black but not silica can also be used.
• the modulus value at 25% elongation (M25), the modulus value at 300% elongation (M300) and the modulus value at 400% elongation (M400) have the following relationship. It is preferable to satisfy the formulas (1) and (2), and it is more preferable to satisfy the relational expression (3).
• the tire of the present invention is characterized in that the rubber composition of the present invention described above is used.
• the rubber composition as a member in contact with the road surface of the tread portion. In this case, fuel efficiency, wear resistance and cut resistance can be further improved.
• the present invention it is possible to provide a rubber composition capable of improving wear resistance and cut resistance while having good fuel efficiency when applied to a tire. Further, according to the present invention, it is possible to provide a tire having excellent fuel efficiency, wear resistance and cut resistance.
• the rubber composition of the present invention contains a rubber component composed of natural rubber and / or synthetic isoprene rubber, and syndiotactic 1,2-polybutadiene.
• the syndiotactic 1,2-polybutadiene, the crystalline weight of 7 ⁇ 40 J / g, and a number average molecular weight is equal to or is 6.5 ⁇ 10 4 or more.
• the rubber composition of the present invention preferably contains syndiotactic 1,2-polybutadiene (hereinafter, may be referred to as "sPB") in a rubber component matrix of natural rubber or synthetic isoprene rubber after vulcanization.
• sPB syndiotactic 1,2-polybutadiene
• the sPB is one of the crystalline polymers, and the crystal sacrifices and breaks under high strain to obtain an effect of dissipating input energy, and the sPB is compatible with natural rubber and synthetic isoprene rubber.
• the vulcanized rubber is composed of a crystal portion of sPB and a rubber component / sPB compatible portion.
• a three-dimensional network (double network) can be formed.
• the rubber composition of the present invention is excellent because the double network structure provides a high energy dissipation effect due to the crystal portion of the sPB and flexibility due to the rubber component / sPB compatible portion. Abrasion resistance and cut resistance can be realized.
• the sPB having high crystallinity and a large molecular weight is used, crystal collapse does not occur at the input of low strain that contributes to rolling resistance, and further. Since the molecular weight is larger and the movement of the terminal chain is less than that of other general-purpose resins, deterioration of fuel efficiency can be suppressed.
• the rubber composition of the present invention comprises natural rubber (NR) and / or synthetic isoprene rubber (IR) as a rubber component.
• NR natural rubber
• IR synthetic isoprene rubber
• the rubber component is composed of one or more of natural rubber and synthetic isoprene rubber, a double network of sPB described above is formed in the vulcanized rubber composition, and therefore, when applied to a tire, the rubber component is formed. Abrasion resistance and cut resistance can be improved while having good fuel efficiency.
• Natural rubber (NR) and synthetic isoprene rubber (IR) use isoprene as a monomer and cis-1,4-polyisoprene structure as a main component.
• the natural rubber may be derived from rubber tree or other plant resources.
• isoprene monomer for synthesizing the synthetic isoprene rubber isoprene derived from petroleum or biomass can be used.
• the rubber composition of the present invention the crystal amount is 7 ⁇ 40 J / g, and comprises a number-average molecular weight of 6.5 ⁇ 10 4 or more syndiotactic 1,2-polybutadiene (sPB).
• sPB syndiotactic 1,2-polybutadiene
• the crystal content of the syndiotactic 1,2-polybutadiene is 7 to 40 J / g.
• the crystal content of the sPB is preferably 15 J / g or more, and more preferably 17 J / g or more.
• the crystal amount of sPB is too large, the melting point of sPB becomes too high and it becomes difficult to set the vulcanization temperature for forming a double network, or if the crystal amount becomes too large, the crystals become fracture nuclei. As a result, the elongation at break of the rubber may tend to decrease, and from this viewpoint, it is set to 40 J / g, preferably 36 J / g or less, and more preferably 31 J / g or less.
• the amount of sPB crystallized is the amount of heat of fusion, and is an index showing the rate at which sPB is crystallized. It can be derived from the melting peak measured by a differential scanning calorimeter.
• the number average molecular weight of the syndiotactic 1,2-polybutadiene can more reliably form the above-mentioned double network in the rubber composition after vulcanization, and has low fuel consumption and wear resistance when applied to a tire. and from the viewpoint of further improving the cut resistance, it must be at 6.5 ⁇ 10 4 or more.
• the number average molecular weight of the sPB is 8.9 ⁇ 10 4 or more, 10.0 ⁇ 10 4 or more, 11.0 ⁇ 10 4 or more, 12.0 ⁇ 10 4 or more, 13.0 ⁇ 10 4 or more, 14.0 ⁇ 10 4 or more.
• the number average molecular weight of the sPB are crack growth resistance and, from the viewpoint of preventing deterioration of riding comfort when applied to the tire, it is preferable to 50.0 ⁇ 10 4 or less.
• the number average molecular weight of the sPB is 40.0 ⁇ 10 4 or less, 39.0 ⁇ 10 4 or less, 38.0 ⁇ 10 4 or less, 37.0 ⁇ 10 4 or less, 36.010 4 or less, 35.0 ⁇ 10 4 or less, 34.7 ⁇ 10 It can be 4 or less, 34.0 ⁇ 10 4 or less, 33.0 ⁇ 10 4 or less, 32.0 ⁇ 10 4 or less, 31.0 ⁇ 10 4 or less, 30.0 ⁇ 10 4 or less.
• the amount of 1,2-bonds of sPB is preferably 80% by mass or more, preferably 85% by mass or more. Is more preferable. This is because the above-mentioned double network can be more reliably formed in the vulcanized rubber composition, and fuel efficiency, wear resistance and cut resistance when applied to a tire can be further improved. From the same viewpoint, the amount of 1,2-bonds of sPB can be 90% by mass or more, 91% by mass or more, 92% by mass or more, 93% by mass or more, 94% by mass or more, or 95% by mass or more. .. In the present invention, the amount of 1,2-bonds of sPB can be determined by 1 H and 13 C nuclear magnetic resonance (NMR) analysis.
• NMR nuclear magnetic resonance
• the syndiotactic 1,2-polybutadiene has a syndiotacticity of 60% or more, more preferably 65% or more in the 1,2-bond of sPB.
• the syndiotacticity in the 1,2-binding of sPB can be 70% or more, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more or 100%. ..
• the syndiotacticity at the 1,2-bond of sPB can be determined by 1 H and 13 C nuclear magnetic resonance (NMR) analysis.
• the syndiotactic 1,2-polybutadiene is a copolymer obtained by copolymerizing a small amount of conjugated diene such as 1,3-pentadiene and 1-pentyl-1,3-butadiene in addition to 1,3-butadiene. It may be a copolymer of 1,3-butadiene.
• the sPB contains a unit derived from a conjugated diene other than 1,3-butadiene, in one embodiment, the proportion of the unit derived from 1,3-butadiene in all the repeating units of sPB is 80% or more, 85%. It can be 90% or more, 95% or more, 98% or more, or 99% or more.
• the melting point of the syndiotactic 1,2-polybutadiene is not particularly limited, but is preferably 100 to 180 ° C. from the viewpoint of further improving the wear resistance and cut resistance of the rubber composition.
• the melting point of the sPB can be 170 ° C. or lower and 160 ° C. or lower.
• the melting point of the sPB can be 110 ° C. or higher and 120 ° C. or higher.
• the content of the syndiotactic 1,2-polybutadiene in the rubber composition of the present invention is not particularly limited, and can be appropriately changed according to the required cut resistance and other performance.
• the content of the sPB is 10 with respect to 100 parts by mass of the rubber component. It is preferably about 30 parts by mass.
• the content of the sPB is 10 parts by mass or more with respect to 100 parts by mass of the rubber component, the energy dissipation effect is enhanced, and more excellent wear resistance and cut resistance can be obtained.
• the content of the sPB can be 15 parts by mass or more and 20 parts by mass or more with respect to 100 parts by mass of the rubber component.
• the content of the sPB is 30 parts by mass or less with respect to 100 parts by mass of the rubber component, deterioration of fuel efficiency can be suppressed.
• the method for obtaining the sPB is not particularly limited, and it can be produced by itself or a commercially available product can be used.
• the 1,3-butadiene monomer can be obtained by polymerizing in an organic solvent containing an aliphatic solvent using an iron-based catalyst composition, a chromium-based catalyst composition, a cobalt-based catalyst composition, or the like.
• iron-based catalyst composition examples include (a) an iron-containing compound, (b) a catalyst composition obtained by mixing an ⁇ -acylphosphonic acid diester and (c) an organoaluminum compound, and (a) an iron-containing compound.
• a catalytic composition obtained by mixing (b) ⁇ -acylphosphonic acid diester, (c) organoaluminum compound and other organometallic compound or Lewis base, or (a) iron-containing compound and (b) dihydrocarbyl hydrogen phosphite.
• a catalyst composition containing an organoaluminum compound and the like examples include (a) an iron-containing compound, (b) a catalyst composition obtained by mixing an ⁇ -acylphosphonic acid diester and (c) an organoaluminum compound, and (a) an iron-containing compound.
• the iron-containing compound (a) is not particularly limited, but preferred examples include iron carboxylate, iron organic phosphate, iron organic phosphonate, iron organic phosphinate, and iron carbamate. Examples thereof include iron dithiocarbamate, iron xanthogenate, iron ⁇ -diketonate, iron alkoxide or aryl oxide, and organic iron compounds. Among these compounds, the iron-based catalyst composition is more reliable in that the crystal content of sPB can be controlled in the range of 7 to 40 J / g and the number average molecular weight in the range of 6.5 ⁇ 10 4 or more.
• it contains tris (2-ethylhexanoic acid) iron (III), bis (2-ethylhexyl) phosphite, triisobutylaluminum, tri-n-butylaluminum and tri-n-octylaluminum.
• the chromium-based catalyst composition examples include a three-component catalyst system containing (a) a chromium-containing compound, (b) a hydrogenated alkylaluminum compound, and (c) a hydrogen phosphite ester.
• a chromium-containing compound As the component (a) of the chromium-based catalyst composition according to the present invention, various chromium-containing compounds can be used. In general, it is advantageous to use chromium-containing compounds that are soluble in hydrocarbon solvents such as aromatic hydrocarbons, aliphatic hydrocarbons or alicyclic hydrocarbons, but simply dispersed in the polymerization medium. It is also possible that the chromium-containing compounds of the above produce catalytically active species.
• chromium-containing compound examples include, but are not limited to, chromium carboxylate, chromium ⁇ -diquetonate, chromium alkoxide or allyloxide, chromium halide, chromium halide, and an organic chromium compound. Can be mentioned.
• the cobalt-based catalyst composition includes soluble cobalt such as cobalt octoate, cobalt 1-naphthate, cobalt benzoate and the like, organoaluminum compounds such as trimethylaluminum, triethylaluminum, tributylaluminum, triphenylaluminum and the like, and carbon disulfide.
• soluble cobalt such as cobalt octoate, cobalt 1-naphthate, cobalt benzoate and the like
• organoaluminum compounds such as trimethylaluminum, triethylaluminum, tributylaluminum, triphenylaluminum and the like
• carbon disulfide soluble cobalt
• a catalyst system consisting of and the like can be mentioned.
• JSR RB registered trademark
• JSR RB registered trademark 810, 820, 830, 840 of JSR Corporation
• the rubber composition of the present invention preferably further contains a filler in addition to the above-mentioned rubber component and syndiotactic 1,2-polybutadiene.
• a filler By including the filler, the wear resistance and the cut resistance of the rubber composition can be compatible with each other at a higher level.
• the filler is not particularly limited, and carbon black, silica, aluminum hydroxide, clay, alumina, talc, mica, kaolin, glass balloon, glass beads, calcium carbonate, magnesium carbonate, magnesium hydroxide, magnesium oxide, and oxidation.
• examples thereof include titanium, potassium titanate, and barium sulfate.
• These fillers may be used alone or in combination of two or more. For example, it may have only carbon black as these fillers.
• the content of the filler is, for example, preferably 10 to 160 parts by mass, more preferably 15 to 140 parts by mass, and 15 to 120 parts by mass with respect to 100 parts by mass of the rubber component. It is more preferably 20 to 120 parts by mass. Further, the content of the filler can be 45 parts or more and 55 parts or less.
• the carbon black is not particularly limited, and for example, SAF, ISAF, IISAF, N339, HAF, FEF, GPF grade carbon black and the like can be used.
• the nitrogen adsorption specific surface area of the carbon black ( measured in accordance with N 2 SA, JIS K 6217-2: 2001) is preferably 20 to 160 m 2 / g, more preferably 25 to 160 m 2. / G, more preferably 25 to 150 m 2 / g, and particularly preferably 30 to 150 m 2 / g.
• the oil absorption of dibutyl phthalate of the carbon black is preferably 40 to 160 ml / 100 g, more preferably 40 to 150 ml / 100 g. It is preferably 50 to 150 ml / 100 g, more preferably 60 to 150 ml / 100 g, and particularly preferably 60 to 140 ml / 100 g.
• One type of carbon black may be used, or two or more types may be used in combination.
• the content of the carbon black is preferably 10 parts by mass or more, and more preferably 20 parts by mass or more with respect to 100 parts by mass of the rubber component, from the viewpoint of enhancing the reinforcing property of the rubber composition. , 30 parts by mass or more is particularly preferable.
• the content of the carbon black is preferably 70 parts by mass or less, preferably 60 parts by mass or less, with respect to 100 parts by mass of the rubber component, from the viewpoint of suppressing deterioration of low loss property and eventually fuel efficiency. Is more preferable.
• silica examples include wet silica (hydrous silicic acid), dry silica (silicic anhydride), calcium silicate, aluminum silicate, etc. Among them, wet silica is preferably used.
• the BET specific surface area (measured based on ISO 5794/1) of the wet silica is preferably 40 to 350 m 2 / g.
• Silica having a BET specific surface area in this range has an advantage that it can achieve both rubber reinforcing properties and dispersibility in rubber components. From this point of view, silica having a BET specific surface area in the range of 80 to 300 m 2 / g is more preferable.
• silica commercially available products such as "Nipcil AQ” and “Nipcil KQ” manufactured by Toso Silica Co., Ltd. and “Ultrasil VN3” manufactured by Evonik Industries can be used.
• One type of silica may be used, or two or more types may be used in combination.
• carbon black is contained as the filler, it is also possible to make a composition which does not contain silica. In this case, it is preferable in that the effect of reducing rolling resistance can be further improved.
• silica when silica is used as the filler, bis (3-triethoxysilylpropyl) polysulfide, bis (3-triethoxysilylpropyl) disulfide and 3-trimethoxysilyl are contained in the rubber composition before vulcanization. It is preferable to further contain a silane coupling agent such as propylbenzothiazil tetrasulfide.
• a silane coupling agent such as propylbenzothiazil tetrasulfide.
• the blending amount of the silane coupling agent in the rubber composition before vulcanization varies depending on the type of the silane coupling agent and the like, but is preferably selected in the range of 2 to 20 parts by mass with respect to 100 parts by mass of the silica. Ru.
• the rubber composition of the present invention appropriately contains other components usually used in the rubber industry, depending on the required performance.
• the other components include a vulcanizing agent (crosslinking agent), a vulcanization accelerator, a vulcanization retarder, an antioxidant, a reinforcing agent, a softening agent, and a vulcanization aid in a rubber composition before vulcanization. It can contain colorants, flame retardants, rubbers, foaming agents, plasticizers, processing aids, antioxidants, scorch inhibitors, UV inhibitors, antistatic agents, color inhibitors, oils and the like. These may be used individually by 1 type or in combination of 2 or more type, respectively.
• examples of the vulcanizing agent include sulfur (powdered sulfur and the like), morpholin / disulfide, and sulfur-containing cross-linking agents such as high molecular weight polysulfides.
• sulfur-containing cross-linking agents such as high molecular weight polysulfides.
• non-sulfur bridges tert-butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, dicumyl peroxide, di-tert-butyl peroxide, diisopropylbenzene hydroperoxide, tert-butyl Peroxide cross-linking such as cumyl peroxide can be mentioned.
• vulcanization accelerator examples include sulfenamide-based vulcanization accelerator, thiazole-based vulcanization accelerator, guanidine-based vulcanization accelerator, thiourea-based vulcanization accelerator, thiuram-based vulcanization accelerator, and dithiocarbamine-based vulcanization accelerator.
• Agents, xanthogenate-based vulcanization accelerators and the like can be mentioned.
• examples of the co-crosslinking agent in the peroxide cross-linking include ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, zinc methacrylate, magnesium methacrylate and the like.
• the method for preparing the rubber composition before vulcanization is not particularly limited, and a known method can be used. For example, it is obtained by adding each compounding component at the same time or in an arbitrary order and kneading using a kneader such as a Banbury mixer, a roll, or an internal mixer.
• a kneader such as a Banbury mixer, a roll, or an internal mixer.
• the method for producing the vulcanized rubber composition of the present invention is not particularly limited.
• the syndiotactic 1,2-polybutadiene and the natural rubber and / or synthetic isoprene rubber in the preparation of the unvulcanized rubber composition, the syndiotactic 1,2-polybutadiene and the natural rubber and / or synthetic isoprene rubber.
• the step of kneading each component by setting the temperature at the time of kneading (during kneading in the master batch kneading stage) to a temperature 10 to 100 ° C. higher than the melting point of the sPB, and the obtained unvulcanized rubber composition.
• Can be used with a production method comprising a step of vulcanizing the rubber at a temperature equal to or higher than the melting point of the sPB.
• the reason for limiting the temperature at the time of kneading the sPB with the natural rubber and / or the synthetic isoprene rubber is that the temperature at the time of kneading is preferably 10 to 100 ° C. higher than the melting point of the sPB. This is because the sPB can be compatible with the rubber component by kneading at a temperature higher by 10 to 50 ° C., more preferably at a temperature higher by 12 to 50 ° C.
• the sPB becomes semi-phase soluble in the rubber component and is immobilized as a network in the rubber component. This is because it is considered that the above-mentioned double network can be formed in the vulcanized rubber composition. However, this does not mean that a double network is not formed at all when vulcanized at a temperature lower than the melting point of sPB.
• the obtained vulcanized rubber composition has excellent cut resistance without deteriorating the low heat generation property.
• the method for confirming that the above-mentioned double network is formed in the vulcanized rubber composition is not particularly limited. For example, by confirming from the phase image of an atomic force microscope (AFM) that the sPB forms a network co-continuous structure in the matrix polymer natural rubber and / or isoprene rubber, the double network The formation can be confirmed.
• AFM atomic force microscope
• the temperature at the time of kneading reaches a temperature 10 ° C. higher than the melting point of the sPB.
• the sPB can be more reliably compatible with the natural rubber and / or synthetic isoprene rubber.
• the temperature at the time of kneading is 100 ° C. higher than the melting point of the sPB.
• the rubber component and the sPB can be suitably prevented from being thermally deteriorated, and as a result, the cut resistance of the obtained vulcanized rubber composition can be improved.
• a kneader such as a Banbury mixer, a roll, or an internal mixer can be used.
• the temperature at the time of kneading in the above-mentioned production method means the temperature of the masterbatch at the time when the masterbatch of the unvulcanized rubber composition is discharged from the kneading apparatus. Specifically, in the masterbatch kneading, the kneading is performed. This is the temperature measured by a temperature sensor or the like inside the masterbatch immediately after being discharged from the device. However, if there is a temperature measuring means for the unvulcanized rubber composition in the kneading device, the temperature of the master batch at the time of discharge may be measured.
• the masterbatch is a rubber composition obtained in a step of kneading the rubber component and the sPB in a kneading step in which a cross-linking agent and a vulcanization accelerator are not blended.
• the vulcanization temperature in the production method is preferably a temperature equal to or higher than the melting point of the sPB.
• the vulcanization temperature is equal to or higher than the melting point of the sPB, it becomes difficult to thermodynamically form a domain structure in which the sPB in the rubber component is in a crystalline state, and the above-mentioned double network can be formed more reliably. Is.
• the temperature at the time of vulcanization in the above-mentioned production method is the maximum temperature reached by the progress of vulcanization from the start of vulcanization (usually, the set temperature of the vulcanization apparatus).
• a known vulcanization system can be used, and it may be a sulfur vulcanization system or a non-sulfur vulcanization system.
• the above-mentioned double network is formed and the durability is improved, but preferably, the modulus value at 25% elongation (M25) and the modulus value at 300% elongation (M25). It is preferable that the M300) and the modulus value (M400) at the time of 400% elongation satisfy the following relational expressions (1) and (2).
• the vulcanized rubber composition is natural.
• M25 MPa
• the value of M400 (MPa) -M300 (MPa) becomes small.
• M25 * M300 / (M400-M300) 2 becomes large.
• the vulcanized rubber composition contains a rubber component composed of natural rubber and / or synthetic isoprene rubber and sPB, and by satisfying the relational expressions (1) and (2), it has low heat generation. Durability such as cut resistance can be improved without causing deterioration.
• the vulcanized rubber composition preferably satisfies the following relational expression (3).
• the tire according to the present invention is a tire using the rubber composition of the present invention described above. Thereby, the tire of the present invention can have excellent fuel efficiency, wear resistance and cut resistance.
• the portion of the tire using the vulcanized rubber composition of the present invention is not particularly limited.
• the vulcanized rubber composition can be suitably used for a portion such as a tread and a sidewall where high durability (particularly, wear resistance and cut resistance) is required.
• the entire tread rubber can be the vulcanized rubber composition of the present invention.
• the member of the tread portion in contact with the road surface can be at least the vulcanized rubber composition of the present invention.
• tires to which the rubber composition of the present disclosure can be expected include tires for truck buses and large tires for mines. Since durability can be expected in particular, it can be expected to be used for tires that are intended for use on rough roads.
• the vulcanized rubber composition is not foam rubber.
• Syndiotactic 1,2-polybutadiene-1 (hereinafter, may be abbreviated as "SPB-1") to Syndiotactic 1,2-polybutadiene-8 (hereinafter, “SPB-8") used in Example 1.
• SPB-1 Syndiotactic 1,2-polybutadiene-1
• SPB-8 Syndiotactic 1,2-polybutadiene-8
• Crystal amount Crystal content (J / g) is obtained by calculating the area of the melting peak observed from -100 ° C to 200 ° C, which is obtained when measuring the melting point, using differential scanning calorimetry (manufactured by TA Instruments). It was.
• a non-production kneading step was carried out with the formulations shown in Table 2.
• the maximum temperature at the time of kneading was 150 ° C.
• the components shown in Table 2 were added to the master batch obtained from the non-production kneading step, and a production vulcanization step was performed to obtain a vulcanized rubber composition.
• the temperature at the time of vulcanization was 160 ° C.
• a non-production kneading step was carried out with the formulations shown in Table 2.
• the maximum temperature at the time of kneading was 177 ° C.
• the reciprocal of the calculated value is taken and displayed as an index value when the reciprocal of the evaluation value of sample 1 is 100, and the larger the value, the better.
• the wear resistance a test piece cut out from each sample of the vulcanized rubber composition in a disk shape (diameter 16.2 mm ⁇ thickness 6 mm) was used, and according to JIS-K6264-2: 2005. A lambourn wear test was conducted to measure the amount of wear (mm 3 ) at 40 ° C and a slip ratio of 25%.
• the reciprocal of the measured value is taken and displayed as an index value when the reciprocal of the amount of wear of sample 1 is 100, and the larger the value, the better.
• the evaluation value of fuel efficiency is on the horizontal axis, and the amount of wear of wear resistance is on the vertical axis, and a straight line connecting the points where the results of Samples 1 and 2 are plotted.
• the above value was set to 100.
• the results of each sample were plotted, and the improved width or the decreased width from the straight line was shown as an index. The larger the index value, the better the wear resistance against fuel consumption.
• the reciprocal of the calculated value is taken and displayed as an index value when the reciprocal of the evaluation value of sample 1 is 100, and the larger the value, the better.
• a tensile test device (Shimadzu Seisakusho Co., Ltd.) was used to perform a test in which a pure shear type test piece was pulled and a notch was made to observe the growth of cracks, and energy was released.
• the crack growth rate was measured when the common logarithm of the rate was 4.8.
• the evaluation of cut resistance is displayed as an index value when the crack growth rate in sample 1 is 100, and the larger the index value, the better the cut resistance.
• the horizontal axis is the evaluation value of fuel efficiency and the vertical axis is the transfer energy of cut resistance, and a straight line connecting the points where the results of Samples 1 and 2 are plotted.
• the above value was set to 100. Then, the results of each sample were plotted, and the improved width or the decreased width from the straight line was shown as an index. The larger the index value, the better the cut resistance against fuel efficiency.
• Syndiotactic 1,2-polybutadiene-9 (hereinafter, may be abbreviated as "SPB-9") and Syndiotactic 1,2-polybutadiene-10 (hereinafter, “SPB-10") used in Example 2.
• SPB-9 Syndiotactic 1,2-polybutadiene-9
• SPB-10 Syndiotactic 1,2-polybutadiene-10
• the polymerization reaction mixture was aggregated with 3 liters of isopropanol containing 2,6-di-tert-butyl-4-methylphenol as an antioxidant.
• the solid content produced was isolated by filtration and dried under reduced pressure at 60 ° C. to a constant weight.
• the yield of the obtained sPB-2 was 41.1 g (yield 91%), and the melting point (melting peak temperature measured by differential scanning calorimetry) was 136 ° C.
• this sPB-2 is 1H and 1
• the 1,2-bond content was 82%
• the syndiotacticity during 1,2-bond was 78%.
• the weight average molecular weight of sPB-2 was 400,000, the crystallinity was 33%, and the crystal weight was 19 J / g.
• the melting points and crystal amounts of sPB-9 and sPB-10 were measured by the same method as in Example 1.
• the weight average molecular weight (Mw), 1,2-bond content, syndiotacticity and crystallinity of 1,2-bonds of sPB-9 and sPB-10 were measured by the following methods. .. (Weight average molecular weight (Mw)) It was measured by gel permeation chromatography [GPC: manufactured by Tosoh, HLC-8220 / HT] using a differential refractometer as a detector, and was shown in polystyrene conversion using monodisperse polystyrene as a standard.
• the column is GMHHR-H (S) HT [manufactured by Tosoh], the eluent is trichlorobenzene, and the measurement temperature is 140 ° C.
• (1,2-bonding content of butadiene, syndiotacticity during 1,2-bonding) Obtained by 1 H and 13 C nuclear magnetic resonance (NMR) analysis of syndiotactic 1,2-polybutadiene. (Crystallinity) Converted from the density measured by the underwater substitution method, assuming that the density of 1,2-polybutadiene with 0% crystallinity is 0.889 g / cm 3 and the density of 1,2-polybutadiene with 100% crystallinity is 0.963 g / cm 3. And calculated.
• Examples 2-1 to 2-9> A non-production kneading step was carried out with the formulations shown in Table 1. The kneading temperature was 160 ° C. Next, the components shown in Table 1 were added to the master batch obtained from the non-production kneading step, and a production vulcanization step was performed to obtain a vulcanized rubber composition. The temperature during vulcanization is shown in Table 1.
• the positive contact loss tan ⁇ was measured under the conditions of frequency 15 Hz, tensile strain 2%, and temperature 24 ° C. using a viscoelasticity measuring device (manufactured by Ueshima Seisakusho). did.
• the evaluation was expressed as an index when the reciprocal of the measured value of tan ⁇ was taken and the reciprocal of sample 2-1 was set to 100. The larger the index value, the smaller the tan ⁇ , indicating that the heat generation is excellent.
• the vulcanized rubber composition of the examples according to the present invention exhibits excellent effects in both the balance between fuel efficiency and abrasion resistance and the balance between fuel efficiency and cut resistance. I understand.
• Example 9 using SPB-7 vulcanization was performed at a temperature 13 ° C. lower than the melting point of SPB, and the double network was not formed, or even if it was formed, it remained in a part. Although it is possible, it can be seen that it has excellent cut resistance.
• the sample of the vulcanized rubber composition according to the present invention has specific vulcanized rubber physical characteristics and exhibits excellent effects in both low heat generation and cut resistance.
• the cut resistance of the samples of the examples showed excellent results as compared with each comparative example, and it can be inferred that this is the effect of forming a double network in the vulcanized rubber composition.
• the present invention it is possible to provide a rubber composition capable of improving wear resistance and cut resistance while having good fuel efficiency when applied to a tire. Further, according to the present invention, it is possible to provide a tire having excellent fuel efficiency, wear resistance and cut resistance.

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