Rubber composition for tire, and tire

Abstract

To provide a rubber composition for a tire exhibiting excellent ICE-WET balance and rolling resistance characteristics when formed into a tire, and to provide a tire produced by using the composition.SOLUTION: A rubber composition for a tire comprising a rubber component, a resin, and silica, wherein the rubber component comprises 30% by mass or more of a butadiene rubber, a total content of a natural rubber and the butadiene rubber is 80% by mass or more, the resin is a resin having an aromatic proton ratio of 20% or more and the following parameter S of 300 or more, and a content of the resin relative to a content of the butadiene rubber is 10 to 100% by mass: Kn represents the retention factor of the n-th peak from the smallest retention time in the total ion chromatogram obtained by pyrolysis gas chromatography-mass spectrometry of the resin, α represents the n of the peak of the maximum retention factor satisfying kn ≤ 6.0, and An represents the ratio (%) of the area of the n-th peak to the total area of the peaks satisfying kn ≤ 6.0.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a rubber composition for a tire and a tire. [Background technology]

[0002] BACKGROUND ART Conventionally, rubber compositions for tires that contain petroleum resins in order to control properties such as viscoelasticity have been known (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-002387 Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, from the viewpoint of safety, there has been a demand for tires (particularly studless tires) to have an improved balance between ice performance and wet performance (hereinafter also referred to as "ice-wet balance"). Furthermore, from the viewpoint of environmental issues, there has also been a demand for improved rolling resistance characteristics. Under these circumstances, the present inventors have studied the rubber composition for tires described in Patent Document 1, and have found that the performance of the rubber composition when used in tires may not necessarily be sufficient.

[0005] In view of the above circumstances, an object of the present invention is to provide a rubber composition for a tire that exhibits excellent ICE-WET balance and rolling resistance properties when made into a tire, and a tire manufactured using the rubber composition for a tire. [Means for solving the problem]

[0006] As a result of extensive research into the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by blending specific resins in a predetermined ratio, and have arrived at the present invention. That is, the present inventors have found that the above problems can be solved by the following configuration.

[0007] (1) A rubber composition containing a rubber component, a resin, and silica, the rubber component contains 30% by mass or more of butadiene rubber, and the total content of natural rubber and butadiene rubber is 80% by mass or more; The resin has a ratio of aromatic hydrocarbon-derived protons determined by an NMR method of 20% or more and a parameter S described below of 300 or more, A rubber composition for tires, wherein the content of the resin relative to the content of the butadiene rubber is 10 to 100% by mass. (2) Further, it contains an aromatic modified terpene resin, The rubber component contains natural rubber, The rubber composition for tires according to (1) above, wherein the content of the aromatic modified terpene resin relative to the content of the natural rubber is 1 to 100% by mass. (3) The rubber composition for a tire according to (1) or (2) above, wherein the parameter S is 300 or more and less than 340. (4) A tire manufactured using the rubber composition for a tire according to any one of (1) to (3) above. [Effects of the Invention]

[0008] As will be described below, according to the present invention, it is possible to provide a rubber composition for a tire that exhibits excellent ICE-WET balance and rolling resistance properties when made into a tire, and a tire manufactured using the rubber composition for a tire. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a total ion chromatogram obtained by pyrolysis GC-MS of resin A. [Figure 2] 1 is a partial cross-sectional schematic view showing an example of an embodiment of a tire of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The rubber composition for tires and the like of the present invention will be described below. In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. Each component may be used alone or in combination of two or more. When two or more components are used in combination, the content of the components refers to the total content unless otherwise specified. Furthermore, with regard to a rubber composition for tires, the ICE-WET balance and rolling resistance characteristics when made into a tire are also simply referred to as "ICE-WET balance" and "rolling resistance characteristics", respectively.

[0011] [I] Rubber composition for tires The rubber composition for tires of the present invention (hereinafter also referred to as "the composition of the present invention") is Contains a rubber component, a resin, and silica, the rubber component contains 30% by mass or more of butadiene rubber, and the total content of natural rubber and butadiene rubber is 80% by mass or more; The resin has a ratio of aromatic hydrocarbon-derived protons determined by an NMR method of 20% or more and a parameter S described below of 300 or more, In the rubber composition for tires, the content of the resin relative to the content of the butadiene rubber is 10 to 100% by mass.

[0012] It is believed that the composition of the present invention can solve the above-mentioned problems because of its structure. The reason for this is not clear, but is presumed to be as follows. As described above, the composition of the present invention contains a predetermined amount of a resin (hereinafter also referred to as a "specific resin") having a ratio of aromatic hydrocarbon-derived protons of 20% or more as determined by NMR (nuclear magnetic resonance) and a parameter S (described below) of 300 or more relative to butadiene rubber (hereinafter also referred to as "BR"). The specific resin has a ratio of aromatic hydrocarbon-derived protons (hereinafter also referred to as "aromatic proton ratio") of 20% or more. The specific resin also has a parameter S (hereinafter also referred to as "S value") described below of 300 or more. Here, the S value is a parameter related to the retention coefficient of peaks (for peaks with a retention coefficient of 6 or less) and area ratio in a total ion chromatogram (hereinafter also referred to as "TIC") of pyrolysis gas chromatography mass spectrometry (hereinafter also referred to as "pyrolysis GC-MS") using a packing material having the following structure, and represents the retention of the monomers constituting the resin on the above packing material.

[0013] Since the specific resin has low compatibility with natural rubber, it is believed that in the composition of the present invention in which the total content of natural rubber and butadiene rubber in the rubber component is 80% by mass or more, the specific resin is incorporated into the butadiene rubber. As a result, the storage modulus at around -20°C does not increase, and the ratio (E'(-20°C) / E'(20°C)) described below becomes small (excellent ice-wet balance).

[0014] [ka]

[0015] Each component contained in the composition of the present invention will be described below.

[0016] [1] Rubber component The composition of the present invention contains a rubber component that contains 30% by mass or more of butadiene rubber, and the total content of natural rubber and butadiene rubber is 80% by mass or more. The rubber component may contain a rubber component other than natural rubber and butadiene rubber. The rubber component may be modified with an alkoxy group, an alkoxysilyl group, or the like.

[0017] [Butadiene rubber] As mentioned above, the rubber component includes butadiene rubber (BR).

[0018] [Content] The content of butadiene rubber in the rubber component is 30% by mass or more. Among them, for reasons of better effects of the present invention, it is preferably 40 to 90% by mass, and more preferably 45 to 70% by mass. The rubber component may be composed only of BR. Multiple BRs may be used in combination.

[0019] [Natural rubber] The rubber component preferably contains natural rubber (NR) because this provides better effects of the present invention.

[0020] [Content] The content of natural rubber in the rubber component is not particularly limited, but is preferably 10 to 70% by mass, more preferably 40 to 60% by mass, for reasons of better effects of the present invention.

[0021] [Total content of natural rubber and butadiene rubber] The total content of natural rubber and butadiene rubber in the rubber component is 80% by mass or more. In particular, 90% by mass or more is preferred for the reason that the effects of the present invention are more excellent. The upper limit of the content is not particularly limited, and is 100% by mass.

[0022] [Other rubber components] The rubber component may contain rubber components other than BR and NR (other rubber components). Examples of such other rubber components include aromatic vinyl-conjugated diene copolymer rubber, isoprene rubber (IR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), and chloroprene rubber (CR). Examples of the aromatic vinyl-conjugated diene copolymer rubber include styrene-butadiene rubber (SBR) and styrene-isoprene copolymer rubber. The other rubber component is preferably SBR, since this provides a better effect of the present invention.

[0023] [Content] The content of other rubber components in the rubber component is preferably 20% by mass or less, and more preferably 10% by mass or less, for the reason that the effects of the present invention are more excellent.

[0024] [Average Tg] The glass transition temperature of the rubber component as a whole (hereinafter also referred to as "average Tg") is not particularly limited, but for reasons of superior effects of the present invention, it is preferably from -120°C to -30°C, and more preferably from -100°C to -50°C. Here, the average Tg of the rubber component is the sum (weighted average value of glass transition temperatures) obtained by multiplying the glass transition temperature (Tg) of each rubber component by the mass fraction of each rubber component.

[0025] [Molecular weight] The weight average molecular weight (Mw) of the rubber component is preferably 100,000 to 10,000,000, and more preferably 300,000 to 3,000,000, for the reason that the effects of the present invention are more excellent. The number average molecular weight (Mn) of the rubber component contained in the composition of the present invention is preferably 50,000 to 5,000,000, and more preferably 150,000 to 1,500,000, for reasons of better effects of the present invention. It is preferable that the Mw and / or Mn of at least one rubber component contained in the rubber component falls within the above range, and it is more preferable that the Mw and / or Mn of all rubber components contained in the rubber component fall within the above range. In this specification, Mw and Mn are values ​​calculated as standard polystyrene obtained by gel permeation chromatography (GPC) measurement under the following conditions. Solvent: Tetrahydrofuran Detector: RI detector

[0026] [2] Specific resin The composition of the present invention contains a resin (specific resin) having a ratio of aromatic hydrocarbon-derived protons (aromatic proton ratio) of 20% or more as determined by NMR and a parameter S (S value) described below of 300 or more.

[0027] [Aromatic proton ratio] The aromatic proton ratio of the specific resin is 20% or more. The aromatic proton ratio is preferably 22% or more, more preferably 24% or more, because the effects of the present invention are more excellent. There is no particular upper limit to the ratio, but the aromatic proton ratio is preferably 80% or less, more preferably 50% or less, because the effects of the present invention are more excellent.

[0028] The aromatic proton ratio is determined as follows. Resin is dissolved in a solvent 1 The H-NMR spectrum is measured. In the spectrum, the ratio of the area of ​​the peaks of protons derived from aromatic hydrocarbons (aromatic rings) to the total area of ​​the peaks of protons derived from the resin is calculated, and this is taken as the aromatic proton ratio. For example, when the resin is a styrene polymer (polystyrene), the aromatic proton ratio is the ratio of the peak area of ​​protons derived from benzene rings to the sum of the peak areas of protons derived from polystyrene.

[0029] [S value] The specific resin has a parameter S (S value) of 300 or more.

[0030]

number

[0031] where k n represents the retention coefficient of the nth peak from the smallest retention time in the total ion chromatogram obtained by pyrolysis gas chromatography mass spectrometry of the resin, and α represents the retention coefficient of the nth peak from the smallest retention time in the total ion chromatogram obtained by pyrolysis gas chromatography mass spectrometry of the resin, and k n represents the n above of the peak with the maximum retention factor of ≦6.0, and A n is k n It represents the ratio (%) of the area of ​​the nth peak to the total area of ​​peaks that satisfy the condition ≦6.0.

[0032] For reasons of better effects of the present invention, the S value is preferably 300 or more and less than 340. Among these, for reasons of better effects of the present invention, the S value is preferably 310 or more, more preferably 320 or more, and even more preferably 330 or more.

[0033] The pyrolysis gas chromatography mass spectrometry (pyrolysis GC-MS) is carried out under the following conditions.

[0034] (conditions) - Instrument name: Shimadzu GCMS-QP2020 Pyrolysis equipment name: Frontier Labs Double Shot Pyrolyzer PY-2020iD ·Thermal decomposition temperature: 550℃ ·Inlet temperature: 320℃ Column used: 5% diphenyldimethl polysiloxane (GL Sciences UA-5) Column size: Length 30m, inner diameter 0.25mm, film thickness 0.25μm Method (column temperature conditions): 70°C (3 min) → Heat at 10°C / min (25 min) → Final temperature 320°C Carrier gas: Ultra-high purity helium gas (total flow rate: 104 mL / min, column flow rate: 1 mL / min) ·Injection volume: 1μL

[0035] A specific example of how to calculate the S value is shown below. 1 shows a total ion chromatogram (TIC) obtained by pyrolysis GC-MS of Resin A, which will be described later. The pyrolysis GC-MS conditions were as described above. As shown in Figure 1, the TIC of Resin A has two peaks. The retention factor k1 of the peak with the shortest retention time (the left peak) is 1.7, and the retention factor k2 of the peak with the second shortest retention time (the right peak) is 2.8. Since the retention factors of both peaks are 6.0 or less, k nThe peak with the largest retention factor that satisfies ≦6.0 is the right peak. Because the right peak is the second peak from the shortest retention time, α in the parameter S is 2. Furthermore, the ratio A1 of the area of ​​the left peak to the sum of the areas of the two peaks is 40(%), and the ratio A2 of the area of ​​the right peak to the sum of the areas of the two peaks is 60(%). Therefore, the S value of Resin A is calculated as 1.7×40+2.8×60=236.

[0036] One example of a method for achieving an S value of 300 or greater is to polymerize a resin using a monomer containing an aromatic hydrocarbon having a polymerizable group, and increase the proportion of components in the aromatic hydrocarbons that have a high retention coefficient (the aforementioned retention coefficient) (preferably components with a retention coefficient of 2 or greater, more preferably components with a retention coefficient of 3 or greater). To enhance the effects of the present invention, the proportion is preferably 50% by mass or greater, more preferably 70% by mass or greater, and even more preferably 90% by mass or greater. The upper limit of the proportion is not particularly limited, and is 100% by mass. Since aliphatic hydrocarbons are likely to decompose at the decomposition temperature (550°C) of the pyrolysis GC-MS described above, the presence of aliphatic hydrocarbons in the monomers that make up the resin is thought to have little effect on the S value.

[0037] [Preferred embodiment] The monomer constituting the specific resin preferably contains an aromatic hydrocarbon having a polymerizable group (for example, a vinyl group, an isopropenyl group, etc.) because this provides a better effect of the present invention. Specific examples of the aromatic hydrocarbon include styrene, α-methylstyrene, vinyltoluene, isopropenyltoluene, indene, and methylindene. Among these, vinyltoluene, isopropenyltoluene, indene, and methylindene are preferred, and isopropenyltoluene, indene, and methylindene are more preferred, because they provide better effects of the present invention.

[0038] For reasons of better effects of the present invention, the retention coefficient of the aromatic hydrocarbons (the retention coefficient described above) is preferably 1 or more, more preferably 2 or more, and even more preferably 3 or more. There is no particular upper limit to the retention coefficient, but for reasons of better effects of the present invention, it is preferably 6 or less, and more preferably 5 or less.

[0039] The monomers constituting the specific resin 6 preferably contain aliphatic hydrocarbons (preferably aliphatic hydrocarbons containing unsaturated double bonds) in addition to the above-mentioned aromatic hydrocarbons. The aliphatic hydrocarbon may be linear, branched, or cyclic. Specific examples of the aliphatic hydrocarbons include aliphatic hydrocarbons that constitute C5 fractions, such as isoprene and cyclopentadiene.

[0040] When the monomer constituting the specific resin contains aliphatic hydrocarbons (e.g., C5 fractions) in addition to the aromatic hydrocarbons described above, the content of the aromatic hydrocarbons in the monomer is preferably 10 to 90 mass%, more preferably 20 to 80 mass%, even more preferably 30 to 70 mass%, and particularly preferably 40 to 60 mass%, for reasons of better effects of the present invention. When the monomer constituting the specific resin contains aliphatic hydrocarbons (e.g., C5 fraction) in addition to the aromatic hydrocarbons described above, the content of the aliphatic hydrocarbons in the monomer is preferably 10 to 90 mass%, more preferably 20 to 80 mass%, even more preferably 30 to 70 mass%, and particularly preferably 40 to 60 mass%, for reasons of better effects of the present invention.

[0041] [Molecular weight] The weight average molecular weight (Mw) of the specific resin is preferably 100 or more and less than 100,000, more preferably 200 to 50,000, and even more preferably 500 to 10,000, for reasons of better effects of the present invention.

[0042] [Content] In the composition of the present invention, the content of the specific resin relative to the content of the BR is 10 to 100% by mass, preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and even more preferably 30 to 70% by mass, because this provides better effects of the present invention.

[0043] In the composition of the present invention, the content of the specific resin is preferably 1 to 100 parts by mass, more preferably 5 to 50 parts by mass, and even more preferably 10 to 30 parts by mass, per 100 parts by mass of the rubber component, because this provides better effects of the present invention.

[0044] [3] Silica The composition of the present invention contains silica. The silica is not particularly limited, and any conventionally known silica can be used. Examples of silica include wet silica, dry silica, fumed silica, and diatomaceous earth. Biomass-derived silica such as rice husks may also be used. The silica may be used alone or in combination of two or more types.

[0045] [CTAB] The cetyltrimethylammonium bromide (CTAB) adsorption specific surface area of ​​silica (hereinafter, "CTAB adsorption specific surface area" may be simply referred to as "CTAB") is not particularly limited, but for the reason that the effect of the present invention is superior, it is preferred that the specific surface area be 70 to 300 m 2 / g, and 110 to 250m 2 / g is more preferred. Here, the CTAB adsorption specific surface area is a value obtained by measuring the amount of CTAB adsorbed onto the silica surface in accordance with JIS K6217-3:2001 "Part 3: Determination of specific surface area - CTAB adsorption method." Here, the CTAB adsorption specific surface area is a value measured in accordance with JIS K6430:2008, Appendix G.

[0046] [Content] In the composition of the present invention, the content of silica is not particularly limited, but in order to achieve better effects of the present invention, the content is preferably 10 to 300 parts by mass, more preferably 30 to 200 parts by mass, and even more preferably 50 to 150 parts by mass, per 100 parts by mass of the rubber component.

[0047] [4] Optional component The composition of the present invention may contain components (optional components) other than the above-mentioned components, if necessary. Such components include, for example, thermoplastic resins other than the specific resin, fillers other than silica (preferably carbon black or aluminum hydroxide), silane coupling agents, additives for improving performance on ice, such as thermally expandable microcapsules and foaming agent components, microparticle aggregates and porous particles such as cellulose having voids, zinc oxide (zinc white), stearic acid, antioxidants, waxes, processing aids, liquid polymers, thermosetting resins, vulcanizing agents (e.g., sulfur), vulcanization accelerators (accelerators), vulcanization activators, and various other additives commonly used in rubber compositions.

[0048] [Carbon black] The composition of the present invention preferably contains carbon black (hereinafter also referred to as "CB") because the effects of the present invention are more excellent. The carbon black may be used alone or in combination of two or more types. The carbon black is not particularly limited, and various grades such as SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, IISAF-HS, HAF-HS, HAF, HAF-LS, FEF, GPF, and SRF can be used.

[0049] [N2SA] The nitrogen adsorption specific surface area (N2SA) of the carbon black is not particularly limited, but is preferably 50 to 200 m for the reason that the effect of the present invention is more excellent. 2 / g, and 70 to 150m 2 / g is more preferred. Here, the nitrogen adsorption specific surface area (N2SA) is the amount of nitrogen adsorbed onto the surface of carbon black measured according to JIS K6217-2:2001 "Part 2: Determination of specific surface area - Nitrogen adsorption method - Single point method."

[0050] [Content] In the composition of the present invention, the content of carbon black is not particularly limited, but in order to achieve better effects of the present invention, it is preferably 1 to 130 parts by mass, and more preferably 2 to 100 parts by mass, per 100 parts by mass of the rubber component described above.

[0051] [Silane coupling agents] The composition of the present invention preferably contains a silane coupling agent, because this provides better effects of the present invention.

[0052] The silane coupling agent is not particularly limited as long as it is a silane compound having a hydrolyzable group and an organic functional group. The hydrolyzable group is not particularly limited, and examples thereof include an alkoxy group, a phenoxy group, a carboxyl group, and an alkenyloxy group. Of these, an alkoxy group is preferred because the effects of the present invention are more excellent. When the hydrolyzable group is an alkoxy group, the number of carbon atoms in the alkoxy group is preferably 1 to 16, and more preferably 1 to 4, because the effects of the present invention are more excellent. Examples of alkoxy groups having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, and a propoxy group.

[0053] The organic functional group is not particularly limited, but is preferably a group capable of forming a chemical bond with an organic compound, and examples thereof include an epoxy group, a vinyl group, an acryloyl group, a methacryloyl group, an amino group, a sulfide group, a mercapto group, and a blocked mercapto group (protected mercapto group) (for example, an octanoylthio group). Of these, a sulfide group (particularly a disulfide group or a tetrasulfide group), a mercapto group, and a blocked mercapto group are preferred because they provide better effects of the present invention. The silane coupling agents may be used alone or in combination of two or more.

[0054] The silane coupling agent is preferably a sulfur-containing silane coupling agent, since this provides a better effect of the present invention.

[0055] Specific examples of the silane coupling agent include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)disulfide, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl-tetrasulfide, trimethoxysilylpropyl-mercaptobenzothiazole tetrasulfide, triethoxysilylpropyl-methacrylate-monosulfide, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl-tetrasulfide, 3-octanoylthio-1-propyltriethoxysilane, and the like. One of these may be used alone, or two or more may be used in combination.

[0056] [Content] In the composition of the present invention, the content of the silane coupling agent is not particularly limited, but is preferably 2 to 20 parts by mass per 100 parts by mass of the rubber component, because this provides better effects of the present invention.

[0057] In addition, in the composition of the present invention, the content of the silane coupling agent relative to the content of silica described above is preferably 1 to 20 mass %, and more preferably 5 to 15 mass %, because this provides better effects of the present invention.

[0058] [Aromatic modified terpene resin] The composition of the present invention preferably contains an aromatic modified terpene resin as the thermoplastic resin other than the specific resin, because this provides a more excellent effect of the present invention. Examples of aromatic modified terpene resins include YS RESIN TO-85, TO-105, and TO-125 manufactured by Yasuhara Chemical Co., Ltd., Dercolyte TS125 manufactured by DRT, and Sylvatraxx 5000 and Sylvatraxx 5216 manufactured by Kraton.

[0059] [Content] In the composition of the present invention, the content of the aromatic modified terpene resin is not particularly limited, but in order to obtain better effects of the present invention, it is preferably 1 to 50 parts by mass, and more preferably 2 to 10 parts by mass, per 100 parts by mass of the rubber component described above.

[0060] When the rubber component contains natural rubber, the content of the aromatic modified terpene resin relative to the content of the natural rubber is preferably 1 to 100 mass%, more preferably 2 to 50 mass%, and even more preferably 2 to 20 mass%, because this provides better effects of the present invention.

[0061] [5] Method for preparing rubber composition for tires The method for producing the composition of the present invention is not particularly limited, and specific examples thereof include a method of kneading the above-mentioned components using a known method or apparatus (e.g., a Banbury mixer, a kneader, a roll, etc.) When the composition of the present invention contains sulfur or a vulcanization accelerator, it is preferable to first mix the components other than the sulfur and the vulcanization accelerator at a high temperature (preferably 100 to 160°C), cool the mixture, and then mix the sulfur or the vulcanization accelerator. The composition of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

[0062] [II] Tires The tire of the present invention is a tire manufactured using the composition of the present invention described above. The tire of the present invention is preferably a pneumatic tire, and can be filled with air, an inert gas such as nitrogen, or other gases. The tire of the present invention exhibits excellent ICE-WET balance and rolling resistance characteristics, and is therefore particularly suitable as a studless tire.

[0063] 2 is a partial cross-sectional schematic view of a tire showing one example of an embodiment of the tire of the present invention, although the tire of the present invention is not limited to the embodiment shown in FIG.

[0064] In FIG. 2, reference numeral 1 denotes a bead portion, reference numeral 2 denotes a sidewall portion, and reference numeral 3 denotes a tire tread portion. Between the pair of left and right bead portions 1, a carcass layer 4 with fiber cords embedded therein is mounted, and the ends of this carcass layer 4 are folded back and wrapped around the bead core 5 and bead filler 6 from the inside to the outside of the tire. In the tire tread portion 3, a belt layer 7 is disposed on the outer side of the carcass layer 4 around the entire circumference of the tire. In addition, a rim cushion 8 is disposed in the bead portion 1 at the portion that comes into contact with the rim. At least one of the reference numerals 2 to 3, 5 to 6, and 8 (preferably reference numeral 3) is formed from the composition of the present invention described above.

[0065] The tire of the present invention can be manufactured, for example, by a conventionally known method. The gas to be filled into the tire can be normal air or air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, or helium. [Example]

[0066] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0067] [Production of rubber composition for tires] The components shown in Tables 1 and 2 below were blended in the proportions (parts by mass) shown in the tables. Specifically, first, the components except for sulfur and the vulcanization accelerator were kneaded in a 1.7-liter internal mixer for 5 minutes, and then released when the temperature reached 150°C to obtain a master batch. Next, sulfur and the vulcanization accelerator were kneaded into the obtained master batch using an open roll to obtain a rubber composition for tires.

[0068] [evaluation] The resulting rubber compositions for tires were evaluated as follows.

[0069] [ICE-WET balance] The obtained rubber composition for tires was vulcanized at 170°C for 15 minutes using a mold of a predetermined shape (inner dimensions: length 150 mm, width 150 mm, thickness 2 mm) to prepare a vulcanized rubber sheet. The storage modulus at -20°C (E'(-20°C)) and at 20°C (E'(20°C)) of the resulting vulcanized rubber sheet was measured using a viscoelasticity spectrometer (manufactured by Toyo Seiki Seisakusho, Ltd.) in accordance with JIS K6394:2007 under conditions of a tensile strain rate of 10%±2% and a vibration frequency of 20 Hz. The ratio of E'(-20°C) to E'(20°C) (E'(-20°C) / E'(20°C)) was then calculated. For tread patterns as fine as those of studless tires, a higher E'(20°C) suppresses pattern collapse, improving wet braking performance. A lower E'(-20°C) improves road-holding on ice and increases the footprint, improving ICE braking performance. Therefore, the smaller the ratio, the better the ice-wet balance. The results (reciprocal of the ratio) are shown in Tables 1 and 2. The results are expressed as an index, with the reciprocal of the ratio of the standard example being set to 100. A larger index means a smaller ratio and a better ice-wet balance. An index of 101 or more is preferred.

[0070] [Rolling resistance characteristics] Vulcanized rubber sheets were prepared as described above. The vulcanized rubber sheet thus obtained was measured for tan δ (tan δ(60°C)) at 60°C under conditions of an elongation deformation strain rate of 10%±2% and a vibration frequency of 20 Hz using a viscoelasticity spectrometer (manufactured by Toyo Seiki Seisakusho, Ltd.) in accordance with JIS K6394:2007. The results (reciprocals) are shown in Tables 1 and 2. The results are expressed as an index, with the reciprocal of tan δ (60°C) of the standard example being set to 100. A larger index means a smaller tan δ (60°C) and better rolling resistance properties (smaller rolling resistance). An index of 101 or more is preferred.

[0071] [Table 1]

[0072] [Table 2]

[0073] In Tables 1 and 2, the column "specific resin relative to BR [% by mass]" indicates the content [% by mass] of resins D to E (specific resins) relative to the BR content.

[0074] 〔resin〕 The resins in Tables 1 and 2 are as follows. Resins D to E have an aromatic proton ratio of 20% or more and an S value of 300 or more, and therefore all fall under the above-mentioned specific resins. On the other hand, resins A to C and G to H do not fall under the above-mentioned specific resins, because they have an S value of less than 300 or an aromatic proton ratio of less than 20%. Furthermore, the Mw of resins A to H is all less than 100,000. Resin A: Resin obtained by thermal polymerization of α-methylstyrene and styrene in a 6 / 5 (mass ratio) ratio (aromatic proton ratio: 54%, S value: 236) Resin B: Resin obtained by thermal polymerization of styrene and indene in a 2 / 3 (mass ratio) ratio (aromatic proton ratio: 53%, S value: 283) Resin C: A resin obtained by thermal polymerization of C5 fraction and indene in a 4 / 1 (mass ratio) ratio (aromatic proton ratio: 12%, S value: 355) Resin D: A resin obtained by thermal polymerization of styrene, α-methylstyrene, vinyltoluene, indene, and isopropenyltoluene in a mass ratio of 3 / 14 / 68 / 13 / 2 (aromatic proton ratio: 37%, S value: 308, Mw: 1522). Resin E: A resin obtained by thermal polymerization of C5 fraction, styrene, α-methylstyrene, vinyltoluene, indene, isopropenyltoluene, and methylindene in a mass ratio of 100 / 3 / 4 / 24 / 28 / 9 / 32 (aromatic proton ratio: 25%, S value: 336, Mw: 1936). Resin G: Yasuhara Chemical YS Resin TO-125 (aromatic modified terpene resin) (aromatic proton ratio: 12%, S value: 122, Mw: 1487) Resin H: Tosoh Corporation's Petrotack 90 (C5 / C9 resin) (aromatic proton ratio: 29%, S value: 272, Mw: 2000)

[0075] [Components other than resin] In Tables 1 and 2, the components other than the resin are as follows. NR: Natural rubber (STR20) SBR: Styrene butadiene rubber (Nipol 1502 manufactured by Nippon Zeon Co., Ltd.) BR: Butadiene rubber (Nipol BR1220 manufactured by Nippon Zeon Co., Ltd.) ·Silica 1: Solvay ZEOSIL 1165MP (CTAB adsorption specific surface area: 160m 2 / g) CB: Showa Cabot Show Black N339 Aromatic modified terpene resin: YS Resin TO-125 (softening point: 125±5°C, manufactured by Yasuhara Chemical Co., Ltd.) Silane coupling agent: Evonik Si69 Thermally expandable microcapsules: Matsumoto Yushi Co., Ltd., F-100D Cellulose aggregate 1: CEOLUS PH-102 manufactured by Asahi Kasei Cellulose aggregate 2: Asahi Kasei CEOLUS UF-F711 Oil: Shell Lubricants Japan Extract No. 4 S Zinc oxide: Three types of zinc oxide manufactured by Seido Chemical Industry Co., Ltd. Stearic acid: NOF Corporation Beads Stearic Acid YR Anti-aging agent: Flexis 6PPD Sulfur: Tsurumi Chemical Industry Co., Ltd. Kinka-in oil-filled fine powder sulfur Vulcanization accelerator (CZ): Noccela CZ-G manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator (DPG): Sumitomo Chemical Co., Ltd., Soxinol DG

[0076] [Summary of Tables 1 and 2] As can be seen from Tables 1 and 2, Examples 1 to 9, which contained the specific resin in a predetermined ratio relative to the BR content, exhibited excellent ice-wet balance and rolling resistance properties. Comparing Example 1 and Example 4 (comparison between embodiments differing only in the type of specific resin), Example 1, in which the S value of the specific resin was 320 or more, exhibited better ICE-WET balance and rolling resistance characteristics. Furthermore, in a comparison of Examples 1 to 3 (comparison between embodiments differing only in the type of rubber component), Examples 1 and 2, in which the butadiene rubber content in the rubber component was 40% by mass or more, exhibited a better ice-wet balance. Furthermore, in a comparison of Examples 1 to 3 (comparison between embodiments differing only in the type of rubber component), Examples 1 and 3, in which the natural rubber content in the rubber component was 40% by mass or more, exhibited better rolling resistance characteristics. Furthermore, a comparison between Example 1 and Example 5 (comparison between the two embodiments with and without Resin G) showed that Example 5, which further contained an aromatic modified terpene resin, exhibited a better ice-wet balance. Furthermore, a comparison between Example 1 and Example 6 (comparison between embodiments that differ only in the content of the specific resin) showed that Example 6, in which the content of the specific resin relative to the content of BR was 45 mass% or more, exhibited better ICE-WET balance and rolling resistance characteristics. Furthermore, a comparison of Example 5 with Examples 7 to 9 (comparison of the different aspects of the presence or absence of thermally expandable microcapsules and cellulose aggregates 1 and 2) revealed that Examples 7 to 9, which contained thermally expandable microcapsules or cellulose aggregates, exhibited better ice-wet balance and rolling resistance properties. Among them, Examples 8 and 9, which contained cellulose aggregates, exhibited even better ice-wet balance.

[0077] On the other hand, the standard example and comparative examples 4 to 7, which contained a different resin instead of the specific resin, comparative example 1, which contained the specific resin but the butadiene rubber content in the rubber component was less than 30 mass%, comparative example 2, which contained the total content of natural rubber and butadiene rubber in the rubber component was less than 80 mass%, and comparative example 3, which did not contain silica, were insufficient in at least one of the ice-wet balance and rolling resistance characteristics. [Explanation of symbols]

[0078] 1 Bead section 2 Sidewall 3 Tire tread 4 carcass layers 5 bead core 6 Bead filler 7 Belt Layer 8 Rim Cushion

Claims

1. Contains a rubber component, a resin, and silica, the rubber component contains 30% by mass or more of butadiene rubber, and the total content of natural rubber and butadiene rubber is 80% by mass or more; The resin has a ratio of aromatic hydrocarbon-derived protons determined by an NMR method of 20% or more and the following parameter S is 300 or more, The rubber composition for tires, wherein the content of the resin relative to the content of the butadiene rubber is 10 to 100 mass %. [Equation 1] Here, k ｎ represents the retention coefficient of the n-th peak from the shortest retention time in the total ion chromatogram obtained by pyrolysis gas chromatography mass spectrometry of the resin, and α represents the retention coefficient of the n-th peak from the shortest retention time in the total ion chromatogram obtained by pyrolysis gas chromatography mass spectrometry of the resin, and k ｎ represents the n of the peak having the maximum retention factor of ≦6.0, and A ｎ is k ｎ It represents the ratio (%) of the area of ​​the nth peak to the total area of ​​peaks that satisfy the condition ≦6.

0.

2. Further, it contains an aromatic modified terpene resin, The rubber component includes natural rubber, 2. The rubber composition for tires according to claim 1, wherein the content of the aromatic modified terpene resin relative to the content of the natural rubber is 1 to 100% by mass.

3. The rubber composition for a tire according to claim 1, wherein the parameter S is 300 or more and less than 340.

4. A tire manufactured using the rubber composition for tires according to any one of claims 1 to 3.

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