Rubber composition for tire, and tire

Abstract

The present invention addresses the problem of providing: a rubber composition for a tire, the rubber composition coming to exhibit excellent wet grip performance and excellent rolling resistance characteristics; and a tire produced using the composition. This rubber composition for a tire comprises 100 parts by mass of a rubber component including SBR, a resin, and 10-300 parts by mass of silica, wherein the resin has a proportion of protons derived from an aromatic hydrocarbon, as determined by an NMR method, of 20% or higher and has a parameter S of 300 or greater, the content of the resin being 1-200 mass% with respect to the SBR content. kn represents a retention factor for the nth peak from the shorter-retention-time side in a total ion chromatogram of the resin obtained by pyrolysis gas chromatography / mass spectrometry; α represents the n of the peak having a maximum retention factor satisfying kn≤6.0; and An represents a proportion (%) of the area of the nth peak to the total area of peaks satisfying kn≤6.0.

Description

Rubber composition for tires and tires

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

[0002] BACKGROUND ART Conventionally, rubber compositions for tires containing petroleum resins have been known from the viewpoint of controlling properties such as viscoelasticity (for example, Patent Document 1).

[0003] JP 2024-002387 A

[0004] Recently, from the viewpoints of safety, environmental issues, etc., there has been a demand for both wet grip performance and rolling resistance characteristics at high levels. In this context, the present inventors have studied the rubber composition for tires described in Patent Document 1, and have found that the performance 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 tires that exhibits excellent wet grip performance and rolling resistance characteristics when made into a tire, and a tire manufactured using the rubber composition for tires.

[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-mentioned problems can be solved by the following configuration.

[0007] (1) A rubber composition for a tire, comprising 100 parts by mass of a rubber component containing styrene-butadiene rubber, a resin, and 10 to 300 parts by mass of silica, wherein the resin has a ratio of aromatic hydrocarbon-derived protons of 20% or more as determined by an NMR method and a parameter S (described later) of 300 or more, and a content of the resin relative to the content of the styrene-butadiene rubber is 1 to 200% by mass. (2) The rubber component contains a specific styrene-butadiene rubber having a styrene content of 25% by mass or less and a glass transition temperature of -40°C or less, wherein the content of the specific styrene-butadiene rubber is 30% by mass or more in the rubber component, and the styrene content of the specific styrene-butadiene rubber and the parameter S of the resin satisfy the following formula (1): Formula (1): (Styrene content of specific styrene-butadiene rubber) × (parameter S - 300) ≧ 400 (3) The rubber composition for a tire according to (1) above, wherein the content of the styrene-butadiene rubber is 30% by mass or more in the rubber component, and further contains a resin (C2) in addition to the resin (C1), the resin (C2) being a resin having a ratio of aromatic hydrocarbon-derived protons determined by an NMR method of 1 to 15% and having the parameter S of 200 or less, and the total content of the resin (C1) and the resin (C2) relative to the content of the styrene-butadiene rubber is 2 to 100% by mass. (4) The rubber composition for a tire according to any of (1) to (3) above, wherein the parameter S is 330 or more. (5) A tire manufactured using the rubber composition for a tire according to any of (1) to (4) above.

[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 wet grip performance and rolling resistance characteristics when made into a tire, and a tire manufactured using the rubber composition for a tire.

[0009] 1 is a total ion chromatogram obtained by pyrolysis GC-MS of Resin A in Example A. FIG. 2 is a partial cross-sectional schematic view showing an example of an embodiment of a tire of the present invention.

[0010] The rubber composition for tires 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 two or more may be used in combination. When two or more components are used in combination, the content of the components refers to the total content unless otherwise specified. Regarding the rubber composition for tires, the wet grip performance, rolling resistance, abrasion resistance, and dry performance of a tire made from the tire composition are also referred to simply as "wet grip performance," "rolling resistance," "abrasion resistance," and "dry performance," respectively. Excellent wet grip performance, rolling resistance, abrasion resistance, and dry performance are also referred to as "excellent effects of the present invention."

[0011] [I] Rubber Composition for Tire The rubber composition for tire of the present invention (hereinafter also referred to as "the composition of the present invention") contains 100 parts by mass of a rubber component containing styrene-butadiene rubber, a resin, and 10 to 300 parts by mass of silica, wherein 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, and the content of the resin relative to the content of the styrene-butadiene rubber is 1 to 200% by mass.

[0012] The composition of the present invention is believed to be able to solve the above-mentioned problems because of its configuration. 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 an aromatic hydrocarbon-derived proton ratio of 20% or more as determined by NMR (nuclear magnetic resonance) and a parameter S (described below) of 300 or more relative to styrene-butadiene rubber (hereinafter also referred to as "SBR"). The specific resin has a structure similar to SBR because the aromatic hydrocarbon-derived proton ratio (hereinafter also referred to as an "aromatic proton ratio") is 20% or more. Furthermore, the specific resin has a parameter S (hereinafter also referred to as an "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") obtained by pyrolysis gas chromatography mass spectrometry (hereinafter also referred to as "pyrolysis GC-MS") using a packing material (structure shown below) similar in structure to SBR, and represents the retention of the monomers that make up the resin to the packing material. The specific resin has an S value equal to or greater than a specific value, and is therefore considered to have extremely high compatibility with SBR.

[0013]

[0014] As a result, in the composition of the present invention, the rubber component containing SBR and the specific resin are compatible to an extremely high degree, which is thought to lead to excellent wet grip performance and rolling resistance characteristics.

[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 containing styrene-butadiene rubber (SBR). The rubber component may contain rubber components other than SBR. The rubber component may be modified with an alkoxy group, an alkoxysilyl group, or the like.

[0017] [SBR] SBR is a copolymer of styrene and butadiene.

[0018] [Styrene Content] The styrene content of SBR is not particularly limited, but is preferably 10 to 50% by mass, and more preferably 20 to 45% by mass, for reasons of better effects of the present invention. Here, the styrene content refers to the proportion (% by mass) of repeating units derived from styrene relative to the total SBR. Another preferred embodiment of the styrene content is 25% by mass or less.

[0019] [Vinyl Unit Content] The vinyl unit content of SBR is not particularly limited, but is preferably 20 to 60 mol %, more preferably 20 to 50 mol %, for reasons of better effects of the present invention. Here, the vinyl unit content refers to the proportion (mol %) of repeating units of 1,2-vinyl unit bonds among repeating units derived from butadiene in SBR.

[0020] [Glass Transition Temperature] The glass transition temperature (Tg) of SBR is not particularly limited, but is preferably −85° C. to −10° C., and more preferably −50° C. to −20° C., for reasons of better effects of the present invention. The glass transition temperature can be adjusted, for example, by the styrene content or the vinyl unit content. In this specification, the glass transition temperature (Tg) is measured using a differential scanning calorimeter (DSC) at a temperature rise rate of 10° C. / min and calculated by the midpoint method. Another preferred embodiment of the Tg is −40° C. or lower.

[0021] [Preferred embodiment] For reasons of better effects of the present invention, the styrene-butadiene rubber is also preferably a styrene-butadiene rubber having a styrene content of 25% by mass or less and a glass transition temperature of −40° C. or less (hereinafter also referred to as “specific styrene-butadiene rubber”).

[0022] [Content] The content of SBR in the rubber component is preferably 10% by mass or more, more preferably 30% by mass or more, and even more preferably 50% by mass or more, because the effects of the present invention are more excellent. The rubber component may be composed of only SBR. Multiple SBRs may be used in combination.

[0023] [Other Rubber Components] The rubber component may contain rubber components other than SBR (other rubber components). Examples of such other rubber components include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), and chloroprene rubber (CR). Of these, NR and BR are preferred because they provide better effects of the present invention.

[0024] [Average Tg] The glass transition temperature of the entire rubber component (hereinafter also referred to as "average Tg") is not particularly limited, but for reasons of better effects of the present invention, it is preferably −100° C. to −20° C., and more preferably −80° C. to −20° 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, because 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, because the effects of the present invention are more excellent. It is preferable that the Mw and / or Mn of at least one rubber component contained in the rubber component fall 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) (hereinafter also referred to as "resin (C1)" or "resin C1") having a ratio of aromatic hydrocarbon-derived protons (aromatic proton ratio) of 20% or more as determined by an NMR method 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. Because the effects of the present invention are more excellent, the aromatic proton ratio is preferably 22% or more, more preferably 24% or more, even more preferably 26% or more, and particularly preferably 28% or more. There is no particular upper limit to the ratio, but because the effects of the present invention are more excellent, it is preferably 80% or less, and more preferably 50% or less.

[0028] The aromatic proton ratio is determined as follows: １ A H-NMR spectrum is measured. In the spectrum, the ratio of the area of ​​the peak of protons derived from aromatic hydrocarbons (aromatic rings) to the sum of the areas 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 areas of the peaks of protons derived from polystyrene.

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

[0030]

[0031] Here, k ｎ represents the retention coefficient 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, and α represents the retention coefficient 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, 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.

[0032] The S value is preferably 330 or more, and more preferably 350 or more, because the effects of the present invention are more excellent. There is no particular upper limit to the S value, but the S value is preferably 500 or less, and more preferably 400 or less, because the effects of the present invention are more excellent.

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

[0034] (Conditions) - Apparatus name: GCMS-QP2020 manufactured by Shimadzu Corporation - Pyrolysis apparatus name: Double Shot Pyrolyzer PY-2020iD manufactured by Frontier Labs - Pyrolysis temperature: 550°C - Injection port temperature: 320°C - Column used: 5% Diphenyldimethyl polysiloxane (UA-5 manufactured by GL Sciences) - Column size: Length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm - Method (column temperature conditions): 70°C (3 minutes) → Heat at 10°C / minute (25 minutes) → Final temperature 320°C - Carrier gas: Ultra-high purity helium gas (total flow rate: 104 mL / minute, column flow rate 1 mL / minute) - Injection amount: 1 μL

[0035] A specific example of a method for calculating the S value is shown below. Figure 1 shows a total ion chromatogram (TIC) obtained by pyrolysis GC-MS of Resin A in Example A (or Resin H in Example C) (both are the same), which will be described later. The pyrolysis GC-MS conditions are as described above. As shown in Figure 1, there are two peaks in the TIC of Resin A. The retention coefficient k of the peak with the shortest retention time (the left peak) is １ is 1.7, and the retention factor k of the second smallest peak (the peak on the right) is ２ The retention factor of the two peaks is 6.0 or less, so k ｎ The peak with the largest retention factor that satisfies ≦6.0 is the right peak. Since the right peak is the second peak from the shortest retention time, α in the parameter S is 2. Also, the ratio A of the area of ​​the left peak to the sum of the areas of the two peaks is １is 40(%), and the ratio A of the area of ​​the right peak to the total area of ​​the two peaks is ２ Therefore, the S value of Resin A is calculated as 1.7×40+2.8×60=236.

[0036] Examples of methods for achieving an S value of 300 or greater include polymerizing a resin using a monomer containing an aromatic hydrocarbon having a polymerizable group, and increasing the proportion of components in the aromatic hydrocarbons that have a high retention coefficient (the retention coefficient described above) (preferably components with a retention coefficient of 2 or greater, and more preferably components with a retention coefficient of 3 or greater). To achieve superior 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. It should be noted that, because 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 constituting 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 (e.g., a vinyl group, an isopropenyl group, etc.) because the effects of the present invention are more excellent. Specific examples of the aromatic hydrocarbon include styrene, α-methylstyrene, vinyltoluene, isopropenyltoluene, indene, and methylindene. Among them, vinyltoluene, isopropenyltoluene, indene, and methylindene are preferred because the effects of the present invention are more excellent, and isopropenyltoluene, indene, and methylindene are more preferred.

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

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

[0040] When the monomers constituting the specific resin contain aliphatic hydrocarbons (e.g., C5 fractions) in addition to the aromatic hydrocarbons described above, the content of the aromatic hydrocarbons in the monomers is preferably 30 to 99% by mass, more preferably 50 to 97% by mass, and even more preferably 70 to 95% by mass, because the effects of the present invention are more excellent. When the monomers constituting the specific resin contain aliphatic hydrocarbons (e.g., C5 fractions) in addition to the aromatic hydrocarbons described above, the content of the aliphatic hydrocarbons in the monomers is preferably 1 to 70% by mass, more preferably 3 to 50% by mass, and even more preferably 5 to 30% by mass, because the effects of the present invention are more excellent.

[0041] It is also preferable that the styrene content of the above-mentioned styrene-butadiene rubber (particularly the above-mentioned specific styrene-butadiene rubber) and the parameter S (S value) of the specific resin satisfy the following formula (1) because the effects of the present invention are more excellent. Formula (1): (styrene content of styrene-butadiene rubber) × (parameter S - 300) ≧ 400 In formula (1), the styrene content of the styrene-butadiene rubber and the parameter S (S value) of the specific resin are as described above. The unit of the styrene content of the styrene-butadiene rubber is "mass%". In this specification, "(styrene content of styrene-butadiene rubber) × (parameter S - 300)" in formula (1) is also simply referred to as "St amount × (S value - 300)". The lower limit of St amount × (S value - 300) is preferably 500 or more, more preferably 800 or more, and even more preferably 1000 or more because the effects of the present invention are more excellent. Although there is no particular upper limit for St amount×(S value−300), it is preferably 3000 or less, and more preferably 2000 or less, for reasons of better effects of the present invention.

[0042] When the styrene content of the styrene-butadiene rubber is 25% by mass or less and the above formula (1) is satisfied, the S value of the specific resin is 316 or more. In the above formula (1), when the styrene content of the styrene-butadiene rubber is 25% by mass, the S value of the specific resin is 316. Furthermore, when the styrene content of the styrene-butadiene rubber is 25% by mass or less, it can be derived from the relationship with the above formula (1) that the S value of the specific resin is 316 or more. For reasons of better effects of the present invention, the S value is preferably 320 or more, more preferably 330 or more, and even more preferably 350 or more. There is no particular upper limit for the S value, but for reasons of better effects of the present invention, it is preferably 500 or less, more preferably 400 or less.

[0043] [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.

[0044] In the composition of the present invention, the content of the specific resin relative to the content of the SBR (hereinafter also referred to as "specific resin / SBR") is 1 to 200% by mass. For reasons of better effects of the present invention, the content of specific resin / SBR is preferably 2 to 150% by mass, and more preferably 3 to 100% by mass.

[0045] In the composition of the present invention, the content of the specific resin is preferably 1 to 200 parts by mass, more preferably 2 to 150 parts by mass, and even more preferably 3 to 100 parts by mass, per 100 parts by mass of the rubber component, for reasons of better effects of the present invention.

[0046] [3] Silica The composition of the present invention contains silica. There are no particular limitations on the type of silica, and any conventionally known silica can be used. Examples of silica include wet silica, dry silica, fumed silica, and diatomaceous earth. Silica derived from biomass, such as rice husks, may also be used. The silica may be one type alone or two or more types in combination.

[0047] [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 more excellent, it is preferably 70 to 300 m ２ / g, and 110 to 250m ２ Here, the CTAB adsorption specific surface area is a value measured in accordance with JIS K6430:2008, Appendix G.

[0048] In the composition of the present invention, the content of silica is 10 to 300 parts by mass relative to 100 parts by mass of the rubber component. For reasons of better effects of the present invention, the content is preferably 30 to 200 parts by mass, more preferably 40 to 160 parts by mass, and even more preferably 50 to 150 parts by mass.

[0049] [4] Optional Components The composition of the present invention may contain components (optional components) other than the above-mentioned components, if necessary. Examples of such components include resins other than the specific resin (e.g., resin (C2) described below), fillers other than silica (preferably, carbon black or aluminum hydroxide), silane coupling agents, thermally expandable microcapsules, 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.

[0050] [Resin (C2)] In order to obtain better effects of the present invention, the composition of the present invention preferably contains, in addition to the above-described resin C1, a resin having an aromatic proton ratio of 1 to 15% and an S value of 200 or less (hereinafter also referred to as "resin (C2)" or "resin C2").

[0051] [Aromatic Proton Ratio] The aromatic proton ratio of resin C2 is 1 to 15%. For reasons of better effects of the present invention, the aromatic proton ratio is preferably 3% or more, more preferably 5% or more, and even more preferably 7% or more. The method for determining the aromatic proton ratio is as described above.

[0052] [S Value] Resin C2 has an S value of 200 or less. In particular, for reasons of better effects of the present invention, the S value is preferably 100 to 190, more preferably 120 to 170, and even more preferably 130 to 150. The S value is determined as described above.

[0053] Examples of methods for setting the S value to 200 or less include polymerizing a resin using a monomer containing an aromatic hydrocarbon having a polymerizable group, and increasing the proportion of components in the aromatic hydrocarbons that have a low retention coefficient (the retention coefficient described above) (preferably components with a retention coefficient of 3 or less, more preferably components with a retention coefficient of 2 or less). For reasons of superior effects of the present invention, the proportion is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. The upper limit of the proportion is not particularly limited, and is 100% by mass. It should be noted that, because 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 constituting the resin is thought to have little effect on the S value.

[0054] [Preferred embodiment] The monomer constituting Resin C2 preferably contains an aromatic hydrocarbon having a polymerizable group (e.g., a vinyl group, an isopropenyl group, etc.) because the effects of the present invention are more excellent. Specific examples of the aromatic hydrocarbon include styrene, α-methylstyrene, vinyltoluene, isopropenyltoluene, indene, and methylindene. Among these, styrene and α-methylstyrene are preferred, and styrene is more preferred, because the effects of the present invention are more excellent.

[0055] For reasons why the effects of the present invention are more excellent, the retention coefficient of the aromatic hydrocarbons (the retention coefficient described above) is preferably 3 or less, and more preferably 2 or less. There is no particular lower limit to the retention coefficient, but for reasons why the effects of the present invention are more excellent, it is preferably 1 or more.

[0056] The monomers constituting the resin C2 preferably contain aliphatic hydrocarbons (preferably aliphatic hydrocarbons containing unsaturated double bonds) in addition to the aromatic hydrocarbons described above, because this provides a more excellent effect of the present invention. The aliphatic hydrocarbons may be linear, branched, or cyclic. Specific examples of the aliphatic hydrocarbons include aliphatic hydrocarbons constituting C5 fractions, such as isoprene, cyclopentadiene, pentane, and dicyclopentadiene (DCPD).

[0057] The content of the aromatic hydrocarbon in the monomer is preferably 1 to 70% by mass, more preferably 5 to 50% by mass, and even more preferably 20 to 40% by mass, because the effects of the present invention are more excellent. The content of the aliphatic hydrocarbon in the monomer is preferably 30 to 99% by mass, more preferably 50 to 95% by mass, and even more preferably 60 to 80% by mass, because the effects of the present invention are more excellent.

[0058] Resin C2 is preferably an aromatic modified terpene resin, since this provides better effects of the present invention.

[0059] [Molecular Weight] The preferred range of Mw of Resin C2 is the same as that of Resin C1 described above.

[0060] [Content] In the composition of the present invention, the content of resin C2 relative to the content of SBR described above is preferably 0.5 to 50 mass%, more preferably 1 to 40 mass%, even more preferably 2 to 30 mass%, and particularly preferably 5 to 20 mass%, for reasons of better effects of the present invention.

[0061] In the composition of the present invention, the content of resin C2 is preferably 0.5 to 50 parts by mass, more preferably 1 to 40 parts by mass, even more preferably 2 to 30 parts by mass, and particularly preferably 5 to 20 parts by mass, per 100 parts by mass of the rubber component, for reasons of better effects of the present invention.

[0062] [Resin Content] In the composition of the present invention, the total content of the above-mentioned resin (C1) and the above-mentioned resin (C2) relative to the content of the above-mentioned styrene-butadiene rubber (SBR) (hereinafter also referred to as "resin content") is preferably 2 to 100 mass%, more preferably 5 to 70 mass%, even more preferably 10 to 50 mass%, and particularly preferably 20 to 40 mass%, for reasons of better effects of the present invention.

[0063] [C2 / C1] In the composition of the present invention, the content of the above-mentioned resin C2 relative to the content of the above-mentioned resin C1 (hereinafter also referred to as "C2 / C1") is preferably 0.1 to 10, more preferably 0.2 to 5, and even more preferably 0.5 to 2, for reasons of better effects of the present invention.

[0064] [Carbon Black] The composition of the present invention preferably contains carbon black 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 of carbon black such as SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, IISAF-HS, HAF-HS, HAF, HAF-LS, FEF, GPF, and SRF may be used.

[0065] [N ２ SA] The nitrogen adsorption specific surface area (N ２ SA) is not particularly limited, but is preferably 50 to 200 m because the effect of the present invention is more excellent. ２ / g, and 70 to 150m ２ Here, the nitrogen adsorption specific surface area (N2SA) is a value obtained by measuring the amount of nitrogen adsorbed onto the surface of carbon black in accordance with JIS K6217-2:2001 "Part 2: Determination of specific surface area - Nitrogen adsorption method - Single point method."

[0066] [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, the content 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.

[0067] [Silane Coupling Agent] The composition of the present invention preferably contains a silane coupling agent, because the effects of the present invention are more excellent.

[0068] 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, but 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.

[0069] The organic functional group is not particularly limited, but is preferably a group capable of forming a chemical bond with an organic compound, such as an epoxy group, a vinyl group, an acryloyl group, a methacryloyl group, an amino group, a sulfide group, a mercapto group, a blocked mercapto group (protected mercapto group) (e.g., an octanoylthio group), and the like. Among these, a sulfide group (particularly a disulfide group or a tetrasulfide group), a mercapto group, or a blocked mercapto group is preferred because the effects of the present invention are more excellent. The silane coupling agent may be used alone or in combination of two or more.

[0070] The silane coupling agent is preferably a sulfur-containing silane coupling agent, since this provides a better effect of the present invention.

[0071] 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 polysiloxanes represented by the average composition formula of the following formula (1) (hereinafter also referred to as "specific polysiloxanes"), and the like. One of these may be used alone, or two or more may be used in combination.

[0072] (A) ａ (B) ｂ (C) ｃ (D) ｄ (R １ ) ｅ SiO （４－２ａ－ｂ－ｃ－ｄ－ｅ）／２ (1) In formula (1), A represents a divalent organic group containing a sulfide group. B represents a monovalent hydrocarbon group having 5 to 20 carbon atoms. C represents a hydrolyzable group. D represents an organic group containing a mercapto group. R １ represents a monovalent hydrocarbon group having 1 to 4 carbon atoms, and a to e satisfy the following relational expressions: 0<a<1, 0<b<1, 0<c<3, 0≦d<1, 0≦e<2, 0<2a+b+c+d+e<4.

[0073] [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 described above, because this provides better effects of the present invention.

[0074] 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.

[0075] [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 in which the above-mentioned components are kneaded using known methods and devices (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 in the sulfur or vulcanization accelerator. In addition, the composition of the present invention can be vulcanized or crosslinked under conventionally known vulcanization or crosslinking conditions.

[0076] [II] Tire 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.

[0077] Fig. 2 shows 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. 2.

[0078] In Figure 2, reference numeral 1 denotes a bead portion, reference numeral 2 denotes a sidewall portion, and reference numeral 3 denotes a tire tread portion. A carcass layer 4 having fiber cords embedded therein is mounted between the pair of left and right bead portions 1, and the ends of this carcass layer 4 are folded back and wound up around a bead core 5 and a bead filler 6 from the inside to the outside of the tire. In the tire tread portion 3, a belt layer 7 is disposed around the entire circumference of the tire on the outside of the carcass layer 4. In the bead portion 1, a rim cushion 8 is disposed in the portion that contacts the rim. At least one of reference numerals 2-3, 5-6, and 8 (preferably reference numeral 3) is formed from the composition of the present invention described above.

[0079] 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.

[0080] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0081] [Example A]

[0082] [Production of Rubber Composition for Tires] The components shown in Tables 1 and 2 below were blended in the ratios (parts by mass) shown in the tables. Specifically, first, the components except for sulfur and 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 vulcanization accelerator were kneaded into the obtained master batch using an open roll to obtain a rubber composition for tires. Note that the parts by mass in the SBR column represent the net parts by mass of rubber in the SBR (parts by mass excluding extender oil).

[0083] [Wet Grip Performance and Rolling Resistance Properties] 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 produce a vulcanized rubber sheet. Tan δ of the obtained vulcanized rubber sheet was measured at temperatures of 0°C and 60°C using a viscoelasticity spectrometer (manufactured by Toyo Seiki Seisaku-sho, Ltd.) in accordance with JIS K6394:2007 under conditions of an elongation deformation strain rate of 10%±2% and a vibration frequency of 20 Hz. Wet grip performance was evaluated from tan δ at 0°C, and rolling resistance properties were evaluated from tan δ at 60°C. Wet grip performance is shown in Tables 1 and 2 (tan δ (0°C)), with the value of Comparative Example 1 set to 100. A higher index indicates better wet grip performance. In practice, an index greater than 100 is preferable. The rolling resistance characteristics are shown in Tables 1 and 2 as an index (tan δ (60°C)) with the value of Comparative Example 1 being 100. A smaller index means better rolling resistance characteristics (smaller rolling resistance). In practice, an index smaller than 100 is preferable.

[0084]

[0085]

[0086] In Tables 1 and 2, the "Aromatic Proton Ratio" and "S Value" columns show the aromatic proton ratio and S value of the resin (Resins A to G) used in each example, respectively. In Tables 1 and 2, the "Resin / SBR" column shows the content (mass%) of the resin (Resins A to G) relative to the content of SBR in each example.

[0087] [Resins] The resins in Tables 1 and 2 are as follows. Note that resins D to F 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 B and G have an S value of less than 300, and therefore none of them fall under the above-mentioned specific resins. Furthermore, resin C has an aromatic proton ratio of less than 20%, and therefore does not fall under the above-mentioned specific resins. Furthermore, the Mw of resins A to G is all less than 100,000. Resin A: Resin obtained by thermally polymerizing α-methylstyrene and styrene in a ratio of 6 / 5 (mass ratio) (aromatic proton ratio: 54%, S value: 236) Resin B: Resin obtained by thermally polymerizing styrene and indene in a ratio of 2 / 3 (mass ratio) (aromatic proton ratio: 53%, S value: 283) Resin C: Resin obtained by thermally polymerizing C5 fraction and indene in a ratio of 4 / 1 (mass ratio) (aromatic proton ratio: 12%, S value: 355) Resin D: Resin obtained by thermally polymerizing styrene, α-methylstyrene, vinyltoluene, indene, and isopropenyltoluene in a ratio of 3 / 14 / 68 / 13 / 2 (mass ratio) (aromatic proton ratio: 37%, S value: 308, Mw: 1522) Resin E: A resin obtained by thermally polymerizing a C5 fraction, styrene, α-methylstyrene, vinyltoluene, indene, isopropenyltoluene, and methylindene in a ratio of 100 / 3 / 4 / 24 / 28 / 9 / 32 (mass ratio) (aromatic proton ratio: 25%, S value: 336, Mw: 1936). Resin F: A resin obtained by thermally polymerizing a C5 fraction, indene, and methylindene in a ratio of 10 / 63 / 27 (mass ratio) (aromatic proton ratio: 41%, S value: 390, Mw: 1037). Resin G: Petrotack 90 (C5 / C9 resin) manufactured by Tosoh Corporation (aromatic proton ratio: 29%, S value: 272, Mw: 2000).

[0088] [Components other than resin] In Tables 1 and 2, the components other than resin are as follows: NR: SIR20 manufactured by Indonesia SBR: TUFDENE F3420 manufactured by Asahi Kasei Corporation (styrene content: 36% by mass, vinyl unit content: 41 mol%, Tg: -27°C, contains 25 parts by mass of oil extender oil per 100 parts by mass of SBR) BR: Nipol BR1220 manufactured by Zeon Corporation Silica: ZEOSIL 1165MP manufactured by Solvay (CTAB adsorption specific surface area: 160 m ２ / g) CB: Seast N manufactured by Tokai Carbon Co., Ltd. Silane coupling agent 1: Si69 manufactured by Evonik Corporation Silane coupling agent 2: Polysiloxane 1 described in paragraph

[0056] of WO 2014 / 002750 (polysiloxane represented by the following average composition formula, average molecular weight: 860) (corresponding to the above-mentioned specific polysiloxane) (-C ３ H ６ -S ４ -C ３ H ６ -) ０．０８３ (-C ８ H １７ ) ０．６６７ (-OC ２ H ５ ) １．５０ (-C ３ H ６ SH) ０．１６７ SiO ０．７５ ・Oil: Extract No. 4S manufactured by Shell Lubricants Japan Co., Ltd. ・Stearic acid: Beads Stearic Acid YR manufactured by NOF Corporation ・Zinc oxide: Zinc oxide type 3 manufactured by Seido Chemical Industry Co., Ltd. ・Anti-aging agent: 6PPD manufactured by Flexis Co., Ltd. ・Vulcanization accelerator 1: Noccela CZ-G (CZ) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. ・Vulcanization accelerator 2: Soxinol D-G (DPG) manufactured by Sumitomo Chemical Co., Ltd. ・Sulfur: Kinkaji oil-filled fine sulfur manufactured by Tsurumi Chemical Industry Co., Ltd.

[0089] [Summary of Tables 1 and 2] As can be seen from Tables 1 and 2, Examples 1 to 6, which contained a specific resin at a predetermined ratio relative to the SBR content, exhibited excellent wet grip performance and rolling resistance characteristics. Comparing Examples 1 to 3 (comparisons between embodiments that differ only in the type of specific resin), Examples 2 and 3, in which the specific resin had an S value of 330 or greater, exhibited better wet grip performance and rolling resistance characteristics. Of these, Example 3, in which the specific resin had an S value of 350 or greater, exhibited even better wet grip performance and rolling resistance characteristics. Furthermore, comparing Examples 1, 5, and 6 (comparisons between embodiments that used Resin D as the specific resin), Examples 1 and 6, in which the specific resin / SBR ratio was 2% by mass or greater, exhibited better wet grip performance. Of these, Example 1, in which the specific resin / SBR ratio was 50% by mass or less, exhibited better rolling resistance characteristics. Furthermore, when comparing Example 1 and Example 4 (comparison between embodiments differing only in the type of silane coupling agent), Example 4, in which the silane coupling agent was a specific polysiloxane, exhibited superior wet grip performance.

[0090] On the other hand, Comparative Examples 1 to 3 and 6, which contained a resin other than the specific resin instead of the specific resin, had insufficient wet grip performance. Comparative Examples 1 and 6 also had insufficient rolling resistance properties. Furthermore, Comparative Example 4, which contained the specific resin but no SBR, had insufficient wet grip performance. Furthermore, Comparative Example 5, which did not contain silica, had insufficient rolling resistance properties.

[0091] [2] Example B

[0092] [Synthesis of SBR] [Production Example 1] Production of modified initiator Two 4 L stainless steel pressure vessels that had been vacuum dried were prepared. 6,922 g of cyclohexane, 85 g of a compound represented by the following formula (3), and 60 g of tetramethylethylenediamine were charged into the first pressure vessel to produce a first reaction solution. At the same time, 180 g of 2.0 M liquid n-butyllithium and 6,926 g of cyclohexane were charged into a second pressure vessel to prepare a second reaction solution. The molar equivalent ratio of the compound represented by Formula (3), the n-butyllithium, and the tetramethylethylenediamine was 1:1:1. With the pressure of each pressure vessel maintained at 7 bar, the first reaction solution was injected into the continuous reactor through the first continuous channel at an injection rate of 1.0 g / min, and the second reaction solution was injected into the continuous reactor through the second continuous channel at an injection rate of 1.0 g / min using a mass flow meter. The temperature of the continuous reactor was maintained at -10°C, the internal pressure was maintained at 3 bar using a backpressure regulator, and the residence time in the reactor was adjusted to within 10 minutes. The reaction was terminated, yielding a modified initiator (solution state).

[0093] [Polymerization Example 1] Method for producing specific SBR1 Preparation of polymer in first reactor and transfer from first reactor to second reactor Into the first reactor of a continuous reactor in which three reactors were connected in series, a styrene solution in which styrene was dissolved in n-hexane at 60 wt% (28.8 mol / h in terms of styrene), a 1,3-butadiene solution in which 1,3-butadiene was dissolved in n-hexane at 60 wt% (13.3 kg / h (147.5 mol / h in terms of 1,3-butadiene), n-hexane at 47.0 kg / h, a 1,2-butadiene solution in which 1,2-butadiene was dissolved in n-hexane at 2.0 wt% (40 g / h), a solution in which N,N,N',N'-tetramethylethylenediamine (TMEDA) was dissolved in n-hexane at 10 wt% (50.0 g / h) as a polar additive, and the modified initiator prepared in Preparation Example 1 above were continuously injected at a rate of 400.0 g / h. During this process, the temperature of the first reactor was maintained at 55°C, and when the polymerization conversion rate reached 41%, the polymer was transferred from the first reactor to the second reactor via the transfer pipe.

[0094] Preparation of Polymer in Second Reactor and Transfer from Second Reactor to Third Reactor Next, a 1,3-butadiene solution in which 1,3-butadiene was dissolved in n-hexane at a concentration of 60% by mass was injected into the second reactor at a rate of 0.65 kg / h (7.2 mol / h in terms of 1,3-butadiene). During this injection, the temperature of the second reactor was maintained at 65°C, and when the polymerization conversion rate reached 95% or more, the polymer was transferred from the second reactor to the third reactor via a transfer pipe.

[0095] Modification Step Next, a solution (solvent: n-hexane) containing N-(3-(1H-1,2,4-triazol-1-yl)propyl)-3-(trimethoxysilyl)-N-(3-(trimethoxysilyl)propyl)propan-1-amine (structure shown below) as a modifying agent was continuously added to a third reactor [modifying agent: act. Li (activated lithium) = 1:1 (molar equivalent ratio)]. The temperature of the third reactor was maintained at 65°C.

[0096] After that, a 30% by mass solution of IR1520 (manufactured by BASF) as an antioxidant was added to the polymer solution discharged from the third reactor at a rate of 170 g / h and stirred, and TDAE (treated distilled aromatic extract) was added as an extender oil and stirred. The resulting polymer was placed in hot water heated with steam and stirred to remove the solvent, thereby producing a specific SBR1 containing 4.7 parts by mass of TDAE as an extender oil per 100 parts by mass of alkoxysilyl group-modified SBR1 (net modified SBR1).

[0097] [Polymerization Example 2] Method for producing specific SBR2 Polymerization was carried out in the same manner as in the preparation of the polymer in the first reactor in the above-mentioned [Polymerization Example 1], except that a styrene solution obtained by dissolving 60% by mass of styrene in n-hexane, a 1,3-butadiene solution obtained by dissolving 60% by mass of 1,3-butadiene in n-hexane, and a 10% by mass solution of N,N,N',N'-tetramethylethylenediamine (TMEDA) in n-hexane were introduced into the first reactor at rates of 7.7 kg / h (44.4 mol / h in terms of styrene), 11.5 kg / h (127.6 mol / h in terms of 1,3-butadiene), and 40.0 g / h of a solution obtained by dissolving 10% by mass of N,N,N',N'-tetramethylethylenediamine (TMEDA) in n-hexane as a polar additive. The polymer was transferred from the first reactor to the second reactor. Next, a 1,3-butadiene solution containing 60% by mass of 1,3-butadiene dissolved in n-hexane was injected into the second reactor at a rate of 0.65 kg / h (7.2 mol / h in terms of 1,3-butadiene). The temperature of the second reactor was maintained at 65°C, and when the polymerization conversion reached 95% or higher, the polymer was transferred from the second reactor to the third reactor via a transfer pipe. Next, the same modification step and post-treatment step as in [Polymerization Example 1] described above were carried out to produce a specific SBR2 containing 20 parts by mass of TDAE as an extender oil per 100 parts by mass of SBR2 modified with alkoxysilyl groups (net modified SBR2). In the modification step, the ratio of modifier to act. Li (activated lithium) was 1:1 (molar equivalent ratio).

[0098] [Production of Rubber Composition for Tires] The components shown in Tables 3 and 4 below were blended in the ratios (parts by mass) shown in the tables. Specifically, first, all components except sulfur and 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 masterbatch. Next, sulfur and vulcanization accelerator were kneaded into the obtained masterbatch using an open roll to obtain a rubber composition for tires. Note that the parts by mass in the SBR column represent the net parts by mass of rubber in the SBR (parts by mass excluding oil-extended oil). Furthermore, when the SBR used in the examples and comparative examples was an oil-extended product containing oil-extended oil, the amount of oil-extended oil derived from the oil-extended product is not shown in Tables 3 and 4, but the oil-extended oil derived from the oil-extended product was contained in each rubber composition for tires produced as described above.

[0099] [Wet Grip Performance and Rolling Resistance Properties] 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 produce a vulcanized rubber sheet. Tan δ of the obtained vulcanized rubber sheet was measured at temperatures of 0°C and 60°C using a viscoelasticity spectrometer (manufactured by Toyo Seiki Seisaku-sho, Ltd.) in accordance with JIS K6394:2007 under conditions of an elongation deformation strain rate of 10%±2% and a vibration frequency of 20 Hz. Wet grip performance was evaluated from tan δ at 0°C, and rolling resistance properties were evaluated from tan δ at 60°C. Wet grip performance is shown in Tables 3 and 4 as an index (tan δ (0°C)), with the value of Comparative Example 1 set to 100. A higher index indicates better wet grip performance. In practice, an index greater than 100 is preferable. The rolling resistance characteristics are shown in Tables 3 and 4 as an index (tan δ (60°C)) with the value of Comparative Example 1 being 100. A smaller index means better rolling resistance characteristics (smaller rolling resistance). In practice, an index smaller than 100 is preferable.

[0100] [Wear Resistance] The obtained rubber composition for tires was vulcanized in a mold of a predetermined shape (inner dimensions: length 15 cm, width 15 cm, thickness 2 mm) at 170°C for 15 minutes to produce a vulcanized rubber sheet. The wear amount of the obtained vulcanized rubber sheet was measured using a Lambourn abrasion tester (manufactured by Iwamoto Seisakusho Co., Ltd.) in accordance with JIS K6264-2:2005 under conditions of a load of 15.0 kg (147.1 N) and a slip ratio of 25%. The abrasion resistance was measured by converting the reciprocal of the wear amount of each Example and Comparative Example into an index, with the reciprocal of the wear amount of Comparative Example 1 set to 100. The indexes calculated as above are shown in Tables 3 and 4 (Lambourn). A higher index indicates better wear resistance. An index greater than 100 is preferred.

[0101]

[0102]

[0103] In Tables 3 and 4, the "St Amount of SBR" and "Tg of SBR" columns represent the styrene content and glass transition temperature of the SBR (specific SBR 1, 2) used in each example, respectively. The numerical value in the "Tg of SBR" column represents the Tg of the net SBR in each SBR used. In Tables 3 and 4, the "Aromatic Proton Ratio of Resin" and "S Value of Resin" columns represent the aromatic proton ratio and S value of the resin (Resins 1 to 5) used in each example, respectively. In Tables 3 and 4, the "St Amount x (S Value - 300)" column represents the value calculated by multiplying the styrene content of the SBR used in each example by the parameter S-300 of the resin used in each example. In Tables 3 and 4, the column "Resin / SBR" indicates the content (mass%) of resin (Resins 1 to 5) relative to the content of SBR (Specific SBR 1, 2) in each example.

[0104] [Resins] Details of Resins 1 to 5 in Tables 3 and 4 are as follows. The Mw of all Resins 1 to 5 is less than 100,000. Resin 1: Resin obtained by thermally polymerizing a 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 2: Resin obtained by thermally polymerizing a C5 fraction, indene, and methylindene in a mass ratio of 10 / 63 / 27 (aromatic proton ratio: 41%, S value: 390, Mw: 1037). Resin 3: Synthomer E1602 partially hydrogenated resin (aromatic proton ratio: 15%, S value: 250). Resin 3 has an aromatic proton ratio of less than 20%, so it does not fall under the category of specific resins in the present invention. - Resin 4: A resin obtained by thermally polymerizing 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 5: Petrotack 90 (C5 / C9 resin) manufactured by Tosoh Corporation (aromatic proton ratio: 29%, S value: 272, Mw: 2000). Note that Resin 5 has an S value of less than 300, so it does not fall under the category of specific resins in the present invention.

[0105] [Components other than resin] In Tables 3 and 4, the components other than resin are as follows: Specific SBR1: An oil-extended product of SBR1 modified with alkoxysilyl groups, produced in [Polymerization Example 1] above. (Styrene content: 16% by mass, vinyl unit content: 25% by mole, Tg: -60°C, weight-average molecular weight: 749,000, number-average molecular weight: 358,000.)

[0106] Specific SBR2: an oil-extended product of the alkoxysilyl-modified SBR2 produced in Polymerization Example 2 above (styrene content: 25% by mass, vinyl unit content: 20% by mole, Tg: −50° C., weight-average molecular weight: 915,000, number-average molecular weight: 482,000).

[0107] BR: butadiene rubber, manufactured by Zeon Corporation, Nipol BR1220, Tg: -107°C; Silica: ZEOSIL 1165MP manufactured by Solvay (CTAB adsorption specific surface area: 160 m) ２ / g) CB: Carbon black. Vulcan MS manufactured by Cabot Japan. ２ SA: 90m ２ / g Silane coupling agent 1: Si69 manufactured by Evonik Silane coupling agent 2: Polysiloxane 1 described in paragraph

[0056] of WO 2014 / 002750 (polysiloxane represented by the following average composition formula, average molecular weight: 860) (corresponding to the specific polysiloxane described above) (-C ３ H ６ -S ４ -C ３ H ６ -) ０．０８３ (-C ８ H １７ ) ０．６６７ (-OC ２ H ５ ) １．５０ (-C ３ H ６ SH) ０．１６７ SiO ０．７５・Oil: Extract No. 4S manufactured by Shell Lubricants Japan Co., Ltd. ・Zinc oxide: Zinc oxide type 3 manufactured by Seido Chemical Industry Co., Ltd. ・Stearic acid: Beads stearate YR manufactured by NOF Corporation ・Anti-aging agent: 6PPD manufactured by Flexis Co., Ltd. ・Sulfur: Kinka-jirushi oil-containing fine sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. ・Vulcanization accelerator 1: Noccela CZ-G (CZ) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. ・Vulcanization accelerator 2: Soxinol D-G (DPG) manufactured by Sumitomo Chemical Co., Ltd.

[0108] [Summary of Tables 3 and 4] As can be seen from Tables 3 and 4, Examples 1 to 5, which contained a specific resin at a predetermined ratio relative to the SBR content, exhibited excellent wet grip performance and rolling resistance characteristics. Comparing Examples 1 and 2 (comparison between embodiments differing only in the type of specific resin), Example 2, which had a larger value of St amount x (S value - 300), exhibited better wet grip performance, rolling resistance characteristics, and wear resistance.

[0109] [3] Example C

[0110] [Production of Rubber Composition for Tires] The components shown in Tables 5 and 6 below were blended in the ratios (parts by mass) shown in the tables. Specifically, first, the components except for sulfur and 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 vulcanization accelerator were kneaded into the obtained master batch using an open roll to obtain a rubber composition for tires. Note that the parts by mass in the SBR column represent the net parts by mass of rubber in the SBR (parts by mass excluding extender oil).

[0111] [Wet Performance, Rolling Performance, and Dry Performance] 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 produce a vulcanized rubber sheet. Tan δ of the obtained vulcanized rubber sheet was measured at temperatures of 0°C, 20°C, and 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 Seisaku-sho, Ltd.) in accordance with JIS K6394:2007. Wet performance (braking performance on a wet road surface) was evaluated from tan δ at 0°C, rolling performance (RRC) was evaluated from tan δ at 20°C, and dry performance (braking performance on a dry road surface) was evaluated from tan δ at 60°C. Wet performance is shown in Tables 5 and 6 as an index with the standard example value set to 100 (Wet performance). A higher index indicates better wet performance. In practical terms, an index greater than 100 is preferable. Rolling performance is shown in Tables 5 and 6 as an index with the standard example value set to 100 (RRC). A lower index indicates better rolling performance (lower rolling resistance). In practical terms, an index less than 100 is preferable. Dry performance is shown in Tables 5 and 6 as an index with the standard example value set to 100 (Dry performance). A higher index indicates better dry performance. An index greater than 100 is preferable.

[0112]

[0113]

[0114] In Tables 5 and 6, the left number in parentheses in the resin column indicates the aromatic proton ratio (%) of the resin, and the right number indicates the S value of the resin. The resin content column indicates the total resin content (% by mass) relative to the styrene-butadiene rubber content.

[0115] [Resins] The resins in Tables 5 and 6 are as follows. Note that resins A to C 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 resin C1. Furthermore, resins D to F have an aromatic proton ratio of 1 to 15% and an S value of 200 or less, and therefore all fall under the above-mentioned resin C2. On the other hand, resins G to J do not fall under the above-mentioned resin C1 or resin C2. Furthermore, the Mw of resins A to J is all less than 100,000.Resin A: Resin obtained by thermally polymerizing C5 fraction, indene, and methylindene in a ratio of 10 / 63 / 27 (mass ratio) (aromatic proton ratio: 41%, S value: 390, Mw: 1037) Resin B: Resin obtained by thermally polymerizing C5 fraction, styrene, α-methylstyrene, vinyltoluene, indene, isopropenyltoluene, and methylindene in a ratio of 100 / 3 / 4 / 24 / 28 / 9 / 32 (mass ratio) (aromatic proton ratio: 25%, S value: 336, Mw: 1936) Resin C: Resin obtained by thermally polymerizing styrene, α-methylstyrene, vinyltoluene, indene, and isopropenyltoluene in a ratio of 3 / 14 / 68 / 13 / 2 (mass ratio) (aromatic proton ratio: 37%, S value: 308, Mw: 1522) Resin D: T-REZ manufactured by ENEOS Corporation PR803 (DCPD / C9 resin) (aromatic proton ratio: 10%, S value: 172, Mw: 863) Resin E: Yasuhara Chemical Co., Ltd. YS Resin TO-85 (aromatic modified terpene resin) (aromatic proton ratio: 10%, S value: 164, Mw: 1408) Resin F: Yasuhara Chemical Co., Ltd. YS Resin TO-125 (aromatic modified terpene resin) (aromatic proton ratio: 12%, S value: 122, Mw: 1487) Resin G: Resin obtained by thermally polymerizing C5 fraction and indene in a ratio of 4 / 1 (mass ratio) (aromatic proton ratio: 12%, S value: 355) Resin H: Resin obtained by thermally polymerizing α-methylstyrene and styrene in a ratio of 6 / 5 (mass ratio) (aromatic proton ratio: 54%, S value: 236) Resin I: A resin obtained by thermally polymerizing styrene and then hydrogenating it (aromatic proton ratio: 20%, S value: 189). Resin J: Petrotack 90 (C5 / C9 resin) manufactured by Tosoh Corporation (aromatic proton ratio: 29%, S value: 272, Mw: 2000).

[0116] [Components other than resin] In Tables 5 and 6, the components other than resin are as follows: SBR: TUFDENE F3420 manufactured by Asahi Kasei Corporation (styrene content: 36% by mass, vinyl unit content: 41 mol%, Tg: -27°C, containing 25 parts by mass of oil extender oil per 100 parts by mass of SBR) BR: Nipol BR1220 manufactured by Zeon Corporation Carbon black: SEAST N manufactured by Tokai Carbon Co., Ltd. Silica: ZEOSIL 1165MP manufactured by Solvay (CTAB adsorption specific surface area: 160 m ２ / g) Silane coupling agent: Si69 manufactured by Evonik Oil: Extract No. 4 S manufactured by Shell Lubricants Japan Zinc oxide: Zinc oxide type 3 manufactured by Seido Chemical Industry Co., Ltd. Stearic acid: Beads stearate YR manufactured by NOF Corporation Anti-aging agent: 6PPD manufactured by Flexis Sulfur: Kinka-jirushi oil-filled fine sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator (CZ): Noccela CZ-G (CZ) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Vulcanization accelerator (DPG): Soxinol D-G (DPG) manufactured by Sumitomo Chemical Co., Ltd.

[0117] [Summary of Tables 5-6] As can be seen from Tables 5-6, Examples 1-10, which contained a specific resin at a predetermined ratio relative to the SBR content, exhibited excellent wet grip performance and rolling resistance characteristics. In particular, Examples 1-8, which used a combination of resin C1 and resin C2, exhibited excellent dry performance. Furthermore, comparing Examples 1-3 (comparison of embodiments differing only in the type of resin C1), Examples 1-2, in which the S value of resin C1 was 330 or greater, exhibited better wet performance, rolling performance, and dry performance. Of these, Example 3, in which the S value of resin C1 was 350 or greater, exhibited even better wet performance, rolling performance, and dry performance. Furthermore, comparing Example 1 with Examples 4-5 (comparison of embodiments differing only in the type of resin C2), Examples 4-5, in which the S value of resin C2 was 170 or less, exhibited better wet performance, rolling performance, and dry performance. Among them, Example 5, in which the S value of resin C2 was 150 or less, exhibited even better wet performance, rolling performance, and dry performance. Furthermore, comparing Examples 1 to 6 (comparison between embodiments in which the total parts by mass of resin C1 and resin C2 was 20 parts by mass), Examples 1 to 5, in which the C2 / C1 ratio was 0.5 or more, exhibited better dry performance. Furthermore, comparing Examples 1 to 6 (comparison between embodiments in which the total parts by mass of resin C1 and resin C2 was 20 parts by mass), Example 6, in which the C2 / C1 ratio was 0.5 or less, exhibited better wet performance and rolling performance. Furthermore, comparing Example 1 and Example 7 (comparison between embodiments in which only the content of resin C1 and resin C2 differed), Example 1, in which the total content of resin C1 and resin C2 relative to the content of styrene-butadiene rubber was 10% by mass or more, exhibited better wet performance and dry performance. Furthermore, comparing Example 1 and Example 8 (comparison between embodiments differing only in the content of resin C1 and resin C2), Example 1, in which the total content of resin C1 and resin C2 relative to the content of styrene-butadiene rubber was 50 mass% or less, showed better rolling performance.Furthermore, comparing Example 1 with Example 8 (comparison between embodiments differing only in the content of resin C1 and resin C2), Example 1, in which the total content of resin C1 and resin C2 relative to the content of styrene-butadiene rubber was 50 mass% or more, showed better wet performance and dry performance.

[0118] REFERENCE SIGNS LIST 1 Bead portion 2 Sidewall portion 3 Tire tread portion 4 Carcass layer 5 Bead core 6 Bead filler 7 Belt layer 8 Rim cushion

Claims

1. A rubber composition for tires comprising 100 parts by mass of a rubber component containing styrene-butadiene rubber, a resin, and 10 to 300 parts by mass of silica, wherein 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, and the content of the resin relative to the content of the styrene-butadiene rubber is 1 to 200% by mass. 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. The rubber composition for tires according to claim 1, wherein the rubber component contains a specific styrene-butadiene rubber having a styrene content of 25% by mass or less and a glass transition temperature of -40°C or less, the content of the specific styrene-butadiene rubber is 30% by mass or more in the rubber component, and the styrene content of the specific styrene-butadiene rubber and the parameter S of the resin satisfy the following formula (1): Formula (1): (styrene content of specific styrene-butadiene rubber) × (parameter S - 300) ≥ 400 3. A rubber composition for tires according to claim 1, wherein the content of the styrene-butadiene rubber in the rubber component is 30% by mass or more, the rubber composition further contains a resin (C2) in addition to the resin (C1), the resin (C2) being a resin having a ratio of aromatic hydrocarbon-derived protons determined by an NMR method of 1 to 15% and having the parameter S of 200 or less, and the total content of the resin (C1) and the resin (C2) relative to the content of the styrene-butadiene rubber is 2 to 100% by mass.

4. The rubber composition for tires according to any one of claims 1 to 3, wherein the parameter S is 330 or more.

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

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