Rubber composition, vulcanized rubber for tire tread, and tire

Abstract

Provided is a rubber composition having exceptional abrasion resistance and tear resistance while maintaining excellent fuel economy. This rubber composition contains a rubber component and carbon black. The rubber component contains a diene rubber. In the rubber composition, the loss tangent at a strain of 2% (2%tanδ) is 0.095 to 0.195, the hysteresis loss at 80°C and 200% elongation (H80°C-200%) is 0.095 or greater, and the ratio (H80°C-200% / 2%tanδ) is 0.88 or greater.

Description

Rubber composition, vulcanized rubber for tire treads, and tires

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

[0002] Traditionally, rubber products such as tires have required high rubber strength to improve their durability.

[0003] Meanwhile, in line with the growing global concern for environmental issues and the resulting global movement towards carbon dioxide emission regulations, there is a growing demand for more fuel-efficient automobiles. One way to achieve this is to reduce the rolling resistance of tires. Generally, by applying low-heat-generating rubber compositions to tires, particularly the tire tread, the rolling resistance of the tires can be reduced, thereby improving the fuel efficiency of automobiles. Furthermore, low-heat-generating rubber compositions can also be applied to rubber products other than tires to improve fuel efficiency.

[0004] To address the above-mentioned requirements, for example, Patent Document 1 discloses that by blending a predetermined amount of isoprene-based rubber and butadiene rubber with a predetermined amount of carbon black, sulfur, and a sulfide compound represented by a predetermined formula, a rubber composition can be obtained that can produce a tire with excellent fuel efficiency while maintaining rubber strength.

[0005] Japanese Patent Publication No. 2018-109198

[0006] The above-mentioned Patent Document 1 focuses on elongation at break as a measure of rubber strength. Furthermore, according to the inventors' research, it has been found that the rubber composition described in Patent Document 1 may have insufficient tear resistance (suppression of damage or cracking even after prolonged driving) when applied to tires, for example.

[0007] Furthermore, it is generally said that fuel efficiency and wear resistance are mutually exclusive. The conventional rubber compositions described above also have room for improvement in achieving the high wear resistance required for rubber products such as tires.

[0008] Therefore, the object of the present invention is to provide a rubber composition that maintains good fuel efficiency while exhibiting excellent abrasion resistance and tear resistance. Furthermore, the object of the present invention is to provide a vulcanized rubber for tire treads and a tire that maintains good fuel efficiency while exhibiting excellent abrasion resistance and tear resistance.

[0009] In other words, the gist of the present invention that solves the above problems is as follows.

[0010] [1] A rubber composition containing a rubber component and carbon black, wherein the rubber component includes a diene rubber, and the rubber composition has a loss loss tangent (2% tanδ) of 0.095 or more and 0.195 or less at 2% strain, and a hysteresis loss (H) at 80°C and 200% elongation. ８０℃－２００％ ) is 0.095 or higher, (H ８０℃－２００％ A rubber composition characterized in that (2% tanδ) is 0.88 or higher.

[0011] [2] The above (H ８０℃－２００％ The rubber composition according to [1], wherein the ratio of (2% tanδ) is 1.00 or less.

[0012] [3] The rubber composition according to [1] or [2], wherein the rubber component comprises a modified diene rubber.

[0013] [4] The rubber composition according to [3], wherein the modifying group in the modified diene rubber has atoms other than carbon and hydrogen.

[0014] [5] The rubber composition according to [4], wherein the modifying group is one or more selected from nitrogen atoms, oxygen atoms, sulfur atoms, metalloid atoms, and metal atoms.

[0015] [6] The rubber composition according to any one of [1] to [5], wherein the rubber component comprises isoprene rubber.

[0016] [7] The rubber composition according to [6], wherein the isoprene rubber comprises natural rubber.

[0017] [8] The rubber composition according to [7], wherein the proportion of natural rubber in the rubber component is 50% by mass or more and 90% by mass or less.

[0018] [9] The rubber composition according to any one of [1] to [8], wherein the carbon black content with an oil absorption amount (COAN) of the compression sample being 100 to 140 mL / 100 g and a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) being 100 to 135 m ２ / g is 20 parts by mass or more with respect to 100 parts by mass of the rubber component.

[0019]

[10] The rubber composition according to any one of [1] to [9], wherein the carbon black content with an oil absorption amount (COAN) of the compression sample being 70 to 105 mL / 100 g and a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) being 110 to 150 m ２ / g is 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the rubber component.

[0020]

[11] The rubber composition according to any one of [1] to

[10] , wherein the carbon black content with an oil absorption amount (COAN) of the compression sample being 80 to 110 mL / 100 g and a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) being 150 to 220 m ２ / g is 3 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the rubber component.

[0021]

[12] The rubber composition according to any one of [1] to

[11] , further containing silica with a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 180 m ２ / g or more.

[0022]

[13] The rubber composition according to

[12] , wherein the content of the silica with the CTAB being 180 m ２ / g or more is 15 parts by mass or less with respect to 100 parts by mass of the rubber component.

[0023]

[14] A vulcanized rubber for a tire tread, characterized by being obtained by vulcanizing the rubber composition according to any one of [1] to

[13] .

[0024]

[15] A tire, characterized by comprising the vulcanized rubber according to

[14] in a tread portion.

[0025] According to the present invention, it is possible to provide a rubber composition that maintains good low fuel consumption performance and is excellent in abrasion resistance and tear resistance. Further, according to the present invention, it is possible to provide a vulcanized rubber for a tire tread and a tire that maintain good low fuel consumption performance and are excellent in abrasion resistance and tear resistance.

[0026] Explanation diagram of the hysteresis loss (H ８０℃－２００％ )(Wd / Ws) at 80°C and 200% elongation.

[0027] Hereinafter, embodiments of the present invention will be described. However, such description is for the purpose of exemplifying the present invention and does not limit the present invention in any way.

[0028] Note that the compounds described in this specification may be partially or entirely derived from fossil resources, may be derived from biological resources such as plant resources, or may be derived from recycled resources such as used tires. Further, it may be derived from a mixture of any two or more of fossil resources, biological resources, and recycled resources.

[0029] (Rubber Composition) The rubber composition according to an embodiment of the present invention (hereinafter sometimes referred to as "the rubber composition of the present embodiment") contains a rubber component and carbon black. Further, in the rubber composition of the present embodiment, the rubber component includes a diene rubber. And the rubber composition of the present embodiment has, as a first physical property, a loss tangent (2% tan δ) at a strain of 2% of 0.095 or more and 0.195 or less, and as a second physical property, a hysteresis loss (H ８０℃－２００％ ) at 80°C and 200% elongation of 0.095 or more, and as a third physical property, (H ８０℃－２００％ / 2% tan δ) of 0.88 or more.

[0030] The present inventors have found that the relationship between the loss tangent and the hysteresis loss at high temperature and high strain affects the abrasion resistance and tear resistance. And as a result of further intensive studies by the present inventors, surprisingly, when the rubber composition has the above-described first physical property, second physical property, and third physical property, it has been found that low fuel consumption performance, abrasion resistance, and tear resistance can be achieved well in parallel.

[0031] <2% tanδ> The rubber composition of this embodiment has a first physical property, which is that the loss tangent (2% tanδ) at a strain of 2% is 0.095 or more and 0.195 or less. If the 2% tanδ is greater than 0.195, it becomes difficult to satisfy the third physical property described later, and the fuel efficiency is insufficient. Also, if the 2% tanδ is less than 0.095, there is a risk that the quality inherently required for rubber products such as tires will be insufficient. From a similar viewpoint, the 2% tanδ of the rubber composition is preferably 0.100 or more, and preferably 0.185 or less.

[0032] <H ８０℃－２００％ > The rubber composition of this embodiment has a second physical property: hysteresis loss (H) at 80°C and 200% elongation. ８０℃－２００％ ) is 0.095 or higher. H ８０℃－２００％ If H is less than 0.095, it becomes difficult to satisfy the third physical property described later, and there is a risk that the quality originally required for rubber products such as tires will be insufficient. On the other hand, H ８０℃－２００％ The upper limit is not particularly limited. However, H ８０℃－２００％ From the viewpoint of achieving a higher balance of fuel efficiency, wear resistance, and tear resistance, a value of 0.195 or less is preferred, and 0.175 or less is more preferred.

[0033] <H ８０℃－２００％ / 2% tanδ> The rubber composition of this embodiment has a third physical property, (H ８０℃－２００％ The ratio ( / 2% tanδ) is 0.88 or higher. Based on the diligent research of the inventors, H ８０℃－２００％ By having a 2% tanδ of 0.88 or higher, it is possible to achieve a high level of both abrasion resistance and tear resistance. On the other hand, H ８０℃－２００％ If the 2% tanδ is less than 0.88, at least one of the abrasion resistance and tear resistance may be poor.

[0034] In the rubber composition of this embodiment, H ８０℃－２００％ From the viewpoint of achieving a higher level of balance between fuel efficiency, wear resistance, and tear resistance, it is preferable that the tanδ of / 2% is 1.00 or less.

[0035] Furthermore, adjustment of 2% tanδ in the rubber composition, and H ８０℃－２００％These adjustments are not limited to, but can be made by appropriately controlling, for example, the types and compositions of the components constituting the rubber composition (rubber components, fillers, antioxidants, vulcanization accelerators, etc.), as well as the types and amounts of coupling agents.

[0036] <Rubber Components> The rubber composition of this embodiment contains at least a diene rubber as a rubber component. Examples of the above-mentioned diene rubber include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), styrene-isoprene-butadiene rubber (SIBR), butyl rubber, ethylene-propylene rubber (EPM), ethylene-propylene diene rubber (EPDM), chloroprene rubber (CR), acrylonitrile butadiene rubber (NBR), and the like. The diene rubber may be a single type or a combination of two or more types.

[0037] -Modified diene rubber- The above rubber component preferably includes modified diene rubber. In other words, the rubber composition of this embodiment preferably contains modified diene rubber as the diene rubber. By including modified diene rubber, fuel efficiency (low rolling resistance) can be further improved. Modified diene rubber is diene rubber that has been modified with a modifying agent. Modified diene rubber may be a single type or a combination of two or more types.

[0038] The above-mentioned modified diene rubber preferably contains modified butadiene rubber (modified BR). In this case, the dispersion form of carbon black in the rubber component becomes better, and a higher level of balance between tear resistance, wear resistance, and fuel efficiency can be achieved.

[0039] The modifying agent used to obtain the modified diene rubber is not particularly limited, as long as it is capable of modifying the diene rubber (capable of imparting modifying groups to the diene rubber). However, it is preferable that the modifying groups in the modified diene rubber have atoms other than carbon and hydrogen. In this case, the dispersion form of carbon black in the rubber component becomes better, and a higher level of balance between tear resistance, abrasion resistance, and fuel efficiency can be achieved.

[0040] In modified diene rubber, it is more preferable that the modifying group has one or more atoms selected from nitrogen atoms, oxygen atoms, sulfur atoms, metalloid atoms, and metal atoms. In this case, the dispersion form of carbon black in the rubber component of the rubber composition becomes even better, and a higher level of balance between tear resistance, abrasion resistance, and fuel efficiency can be achieved.

[0041] Examples of metalloid atoms include boron, silicon, germanium, arsenic, antimony, and tellurium, but among these, one or more atoms selected from boron, silicon, and germanium are more preferred, and silicon is particularly preferred. Examples of metal atoms include tin, titanium, zirconium, bismuth, and aluminum, but among these, one or more atoms selected from tin and titanium are more preferred, and tin is particularly preferred.

[0042] In the rubber composition of this embodiment, the proportion of modified diene rubber in the rubber component is preferably 10% by mass or more and 50% by mass or less. If the proportion of modified diene rubber is within the above range, carbon black can be dispersed as desired while forming a good sea-island structure together with isoprene rubber, thereby further improving at least one of tear resistance, abrasion resistance, and fuel efficiency. From a similar viewpoint, the proportion of modified diene rubber in the rubber component is more preferably 15% by mass or more, even more preferably 20% by mass or more, even more preferably 40% by mass or less, and even more preferably 35% by mass or less.

[0043] -Isoprene-based rubber- The above rubber component preferably contains isoprene-based rubber. In other words, the rubber composition of this embodiment preferably contains isoprene-based rubber as the diene-based rubber. By including isoprene-based rubber, the mechanical strength can be effectively increased.

[0044] Isoprene rubber is rubber having an isoprene skeleton. Examples of isoprene rubber include natural rubber (NR) and isoprene rubber (IR). Isoprene rubber may be a single type or a combination of two or more types.

[0045] From the viewpoint of dispersing carbon black as desired, isoprene-based rubber preferably contains natural rubber (NR).

[0046] The rubber composition of this embodiment may also contain modified isoprene rubber (modified natural rubber, modified isoprene rubber, etc.). In this case, such modified isoprene rubber will be treated as a modified diene rubber, not an isoprene rubber, by definition. That is, in this specification, isoprene rubber is substantially unmodified isoprene rubber.

[0047] In the rubber composition of this embodiment, the proportion of natural rubber in the rubber component is preferably 50% by mass or more and 90% by mass or less. If the proportion of natural rubber is within the above range, carbon black can be dispersed as desired while forming a good sea-island structure together with the modified diene rubber, thereby further improving at least one of tear resistance, abrasion resistance, and fuel efficiency. From a similar viewpoint, the proportion of natural rubber in the rubber component is more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 85% by mass or less, and even more preferably 80% by mass or less.

[0048] -Other Rubber Components- The rubber composition of this embodiment may contain other rubber components as rubber components other than the modified diene rubber and isoprene rubber described above. However, from the viewpoint of more reliably obtaining the desired effect, the proportion of the above-mentioned other rubber components to the rubber component is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 0% by mass.

[0049] <Carbon Black> The rubber composition of this embodiment contains carbon black as a filler. By including carbon black, wear resistance and tear resistance can be improved. Carbon black may be used alone or in combination of two or more types.

[0050] In the rubber composition of this embodiment, the carbon black content is preferably 30 parts by mass or more and 55 parts by mass or less per 100 parts by mass of rubber component. If the content is 30 parts by mass or more, the interaction with the rubber component is sufficiently increased, and the abrasion resistance and / or tear resistance can be effectively improved. If the content is 55 parts by mass or less, fuel efficiency can be better maintained and processability can be maintained. From a similar viewpoint, the carbon black content per 100 parts by mass of rubber component is more preferably 35 parts by mass or more, more preferably 50 parts by mass or less, and even more preferably 45 parts by mass or less.

[0051] The rubber composition of this embodiment has an oil absorption capacity (COAN) of 100 to 140 mL / 100 g of compressed sample and a CTAB of 100 to 135 m ２ It is preferable to contain carbon black at a concentration of 1 / g (hereinafter sometimes referred to as "carbon black belonging to Group A"). Furthermore, in the rubber composition of this embodiment, it is preferable that the content of carbon black belonging to Group A is 20 parts by mass or more per 100 parts by mass of the rubber component. In this case, the high-structure carbon black is well dispersed in the rubber component, thereby further improving abrasion resistance. Furthermore, it is preferable that the content of carbon black belonging to Group A per 100 parts by mass of the rubber component is 50 parts by mass or less.

[0052] The COAN of the carbon black belonging to Group A above is preferably 110 mL / 100 g or more, and also preferably 130 mL / 100 g or less. Furthermore, the CTAB of the carbon black belonging to Group A above is preferably 110 mL ２ It is 120 m or more. ２ It is less than or equal to / g.

[0053] In this specification, the oil absorption capacity (COAN) (mL / 100g) of the compressed sample is a value measured in accordance with ASTM D3493. COAN is generally used as an indicator of the degree of structure development. In this specification, the specific surface area (CTAB) of cetyltrimethylammonium bromide adsorption (m²) is also used.２ The value ( / g) is measured in accordance with JIS K6217-3.

[0054] The rubber composition of this embodiment has a COAN content of 70 to 105 mL / 100 g and a CTAB content of 110 to 150 mL ２ It is preferable to contain carbon black at a concentration of 1 / g (hereinafter sometimes referred to as "carbon black belonging to Group B"). Furthermore, in the rubber composition of this embodiment, it is preferable that the content of the carbon black belonging to Group B is 3 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the rubber component. If the above content is 3 parts by mass or more and 20 parts by mass or less, tear resistance can be effectively improved while suppressing an excessive increase in loss.

[0055] The COAN of the carbon black belonging to Group B is preferably 75 mL / 100 g or more, and preferably 95 mL / 100 g or less. Furthermore, the CTAB of the carbon black belonging to Group B is preferably 115 mL / 100 g. ２ It is 122m or more, and preferably 122m ２ It is less than or equal to / g.

[0056] The rubber composition of this embodiment has a COAN content of 80 to 110 mL / 100 g and a CTAB content of 150 to 220 mL. ２ It is preferable to contain carbon black at a concentration of 1 / g (hereinafter sometimes referred to as "carbon black belonging to Group C"). Furthermore, in the rubber composition of this embodiment, it is preferable that the content of carbon black belonging to Group C is 3 parts by mass or more and 20 parts by mass or less per 100 parts by mass of the rubber component. If the above content is 3 parts by mass or more and 20 parts by mass or less, tear resistance can be effectively improved while suppressing an excessive increase in loss.

[0057] The adjustment of COAN and CTAB of carbon black can be performed, without limitation, by controlling various conditions such as the raw material oil introduction conditions, air introduction conditions, fuel introduction conditions, and quench amount during the carbon black manufacturing process.

[0058] Furthermore, in order for the rubber composition to possess the first, second, and third physical properties described above, modified carbon black can be used as the carbon black.

[0059] <Silica> The rubber composition of this embodiment contains CTAB as a filler, with 180 m ２ It is preferable to further contain silica in a quantity of 1 / g or more. In other words, in the rubber composition of this embodiment, CTAB is 180m ２ It is preferable that the silica content is greater than 0 parts by mass per 100 parts by mass of rubber component, with a silica content of 1g or more. In this case, further improvement in wear resistance can be expected. The upper limit of the CTAB of the above silica is not particularly limited, but for example, 300m ２ It can be less than or equal to / g.

[0060] In the rubber composition of this embodiment, CTAB is 180 m ２ It is preferable that the silica content, which is 15 parts by mass or less per 100 parts by mass of rubber component, is 15 parts by mass or less. In this case, wear resistance can be effectively improved while suppressing an excessive increase in loss. From a similar viewpoint, it is preferable that the CTAB per 100 parts by mass of rubber component is 180 m ２ The silica content, which is 10 parts by mass or less, is more preferably 8 parts by mass or less, and is even more preferably 10 parts by mass or less, with a silica content of 10 parts by mass or less per gram.

[0061] <Other Components> The rubber composition of this embodiment may contain other fillers besides the fillers described above. Other fillers include, for example, CTAB 180m ２ Examples of fillers with a concentration of less than 1g include silica, aluminum hydroxide, clay, alumina, talc, mica, kaolin, glass balloons, glass beads, calcium carbonate, magnesium carbonate, magnesium hydroxide, magnesium oxide, titanium dioxide, potassium titanate, and barium sulfate. However, from the viewpoint of more reliably obtaining the effects unique to the present invention, it is preferable that the rubber composition of this embodiment does not contain the other fillers mentioned above.

[0062] Furthermore, the rubber composition of this embodiment may contain, as appropriate and within the scope of the present invention, compounding agents commonly used in the rubber industry, such as crosslinking agents (vulcanizing agents) like sulfur, crosslinking accelerators (vulcanization accelerators), antioxidants, process oils, scorch inhibitors, zinc oxide, stearic acid, etc. Commercially available compounding agents can be suitably used. The rubber composition can be manufactured by compounding a rubber component with a filler such as carbon black and various compounding agents as needed, and then kneading, heating, extruding, etc.

[0063] The method for preparing the rubber composition of this embodiment is not particularly limited, and known methods can be used. For example, it can be obtained by kneading each component, including a predetermined rubber component and a filler such as carbon black, using a kneader such as a Banbury mixer, roll mixer, or internal mixer. Alternatively, components other than the crosslinking accelerator and crosslinking agent may be mixed in a non-production (non-pro) stage, and the crosslinking accelerator and crosslinking agent may be added to the mixture and mixed in a production (pro) stage to prepare the rubber composition.

[0064] The rubber composition of this embodiment can be crosslinked or vulcanized. That is, the rubber composition of this embodiment can be crosslinked rubber (vulcanized rubber). The conditions for crosslinking or vulcanizing the rubber composition can be adjusted as appropriate, for example, the temperature can be 120 to 200°C and the heating time can be 1 minute to 900 minutes.

[0065] (Vulcanized rubber for tire treads) A vulcanized rubber for tire treads according to one embodiment of the present invention is characterized by being obtained by vulcanizing the rubber composition described above. Because such a vulcanized rubber for tire treads uses the rubber composition described above, when applied to a tire tread, it can exhibit excellent wear resistance and tear resistance while maintaining good fuel efficiency.

[0066] The conditions for vulcanizing the rubber composition described above can be adjusted as appropriate; for example, the temperature can be 120 to 200°C and the heating time can be 1 minute to 900 minutes.

[0067] (Tire) A tire according to one embodiment of the present invention is characterized by having the above-described vulcanized rubber for tire treads (the rubber composition of this embodiment that has been vulcanized) in the tread portion. Since the tread portion of the above tire is made from the rubber composition of this embodiment, it maintains good fuel efficiency while having excellent wear resistance and tear resistance.

[0068] The method for manufacturing the tire is not particularly limited to using the rubber composition (vulcanized rubber) of this embodiment for the tread, and known methods can be used.

[0069] The present invention will be described in more detail below with reference to examples, but these examples are for illustrative purposes only and do not limit the present invention in any way.

[0070] (Preparation or manufacturing of carbon black) Carbon blacks CB1 to CB3 were manufactured. In the manufacturing of these carbon blacks, various conditions (amount of raw material oil introduced, amount of air introduced, temperature, etc.) were changed as shown in Table 1. In addition, Asahi Carbon's "N234" was prepared as CB4, and Asahi Carbon's "N330" was prepared as CB5.

[0071] For each carbon black, the oil absorption amount (COAN) of the compressed sample was measured in accordance with ASTM D3493. Furthermore, for each carbon black, the cetyltrimethylammonium bromide adsorption specific surface area (CTAB) was measured in accordance with JIS K6217-3. The results are shown in Table 1. In Table 1, "Quench amount" indicates the amount of reaction stopper, and "KOH" indicates the amount of potassium hydroxide aqueous solution.

[0072]

[0073] (Preparation of Rubber Composition) Next, a rubber composition was prepared by thoroughly kneading the materials according to the formulation shown in Table 2. The obtained rubber composition was evaluated according to the following procedure.

[0074] <2% tanδ (Fuel Efficiency)> A 1 mm thick rubber sheet was prepared from the obtained rubber composition and vulcanized at 145°C for 33 minutes to produce a vulcanized rubber sheet. A 4.7 mm x 40 mm strip-shaped test piece was prepared from the vulcanized rubber sheet. The loss tangent (2% tanδ) of the test piece was measured using a spectrometer (manufactured by Toyo Seiki Co., Ltd.) in accordance with JIS K 6394, at a test environment temperature of 30°C, a chuck distance of 10 mm, a strain of 2%, and a frequency of 52 Hz. The results are shown in Table 2. A smaller loss tangent (2% tanδ) indicates better fuel efficiency. Specifically, if the 2% tanδ is 0.195 or less, it can be evaluated as having excellent fuel efficiency.

[0075] <H ８０℃－２００％ > A 2 mm thick rubber sheet was prepared from the obtained rubber composition and vulcanized at 145°C for 33 minutes to produce a vulcanized rubber sheet. From this vulcanized rubber sheet, a donut-shaped test piece with an outer diameter of 12 mm, an inner diameter of 8 mm, and a width of 2 mm was prepared. The test piece was subjected to a tensile testing machine (K18003) manufactured by System One, at 80°C and a chuck distance of 20 mm, stretched to 200% 10 times (after repeating the cycle of 0% → 200% stretch → 0% 10 times), and the hysteresis loss (H) was measured at a tensile speed of 10 mm / min. ８０℃－２００％ The hysteresis loss (H) was calculated (Wd / Ws, energy loss / storage). ８０℃－２００％ The stress-strain ratio (ABCDA / ABCEA) was calculated by the ratio of the area enclosed by ABCDA to the area enclosed by ABCEA in the stress-strain curve diagram shown in Figure 1. The results are shown in Table 2.

[0076] <H ８０℃－２００％ / 2% tanδ> For each example, (H ８０℃－２００％ The formula ( / 2% tanδ) was calculated. The results are shown in Table 2.

[0077] <Abrasion Resistance> In accordance with JIS K 6264-2:2005, the amount of abrasion was measured using a Lambourn abrasion tester manufactured by Ueshima Seisakusho. The measured value of Comparative Example 1 was set to 100, and the reciprocal of the measured value for each example was indexed. The results are shown in Table 2. A larger index value indicates superior abrasion resistance.

[0078] <Tear Resistance> The obtained rubber composition is applied to the tread rubber, and a heavy-duty tire of size 11R22.5 is prototyped according to a standard method. This tire is mounted on the drive axle of a truck and driven for 100,000 km, after which the total length of the tear is measured. The measured value of Comparative Example 3 is set to 100, and the reciprocal of the measured value of each example is indexed, and the tear resistance is evaluated according to the following criteria. The results are shown in Table 2. 5: Index value of 120 or more 4: Index value of 105 or more and less than 120 3: Index value of 95 or more and less than 105 (no problem) 2: Index value of 80 or more and less than 95 (market needs to be limited) 1: Index value less than 80 (not suitable for use)

[0079]

[0080] *1 Modified butadiene rubber: Modified BR prepared by the following procedure *2 Silica: Solvay Silica Korea Co., Ltd, "Zeosil Premium SW MP", CTAB: 255m ２ / g *3 Coupling agent: "CABRUS (registered trademark)-2A" manufactured by Osaka Soda Co., Ltd. *4 Other chemicals: Sulfur, vulcanization accelerator, and antioxidant. The same mixing ratio is used in each example.

[0081] (Preparation of Modified BR) In a dry, nitrogen-purged pressure-resistant glass container of approximately 900 mL, 283 g of cyclohexane, 50 g of 1,3-butadiene, 0.0057 mmol of 2,2-ditetrahydrofurylpropane, and 0.513 mmol of hexamethyleneimine were added. Then, 0.57 mmol of n-butyllithium (BuLi) was added, and polymerization was carried out for 4.5 hours in a 50°C hot water bath equipped with a stirring device. The polymerization conversion rate at this time was approximately 100%. Next, 0.100 mmol of tin tetrachloride was quickly added to this polymerization reaction system as a denaturing agent (coupling agent), and the denaturation reaction was carried out by stirring at 50°C for 30 minutes. Subsequently, 0.5 mL of an isopropanol solution of 2,6-di-t-butyl-p-cresol (BHT) (BHT concentration: 5% by mass) was added to the polymerization reaction system to stop the reaction, and the reaction was further dried according to a conventional method to obtain modified butadiene rubber (modified BR) containing tin atoms. Regarding the obtained modified BR, １The amount of vinyl bonding in the butadiene portion was measured from the integration ratio of the 1H-NMR spectrum and found to be 14%. The glass transition temperature (Tg) was determined from the inflection point of the DSC curve and found to be -95°C. The coupling rate was determined from the ratio of the peak area on the highest molecular weight side to the total area of ​​the molecular weight distribution curve obtained by gel permeation chromatography (GPC) and found to be 65%.

[0082] Table 2 shows that the rubber composition of the example has a first physical property (2% tanδ) and a second physical property (H ８０℃－２００％ ), and the third physical property (H ８０℃－２００％ The combination of (2% tanδ) demonstrates that it achieves both excellent fuel efficiency and good wear resistance and tear resistance.

[0083] On the other hand, it can be seen that the comparative rubber composition does not have good abrasion resistance or tear resistance.

[0084] According to the present invention, it is possible to provide a rubber composition that maintains good fuel efficiency while exhibiting excellent abrasion resistance and tear resistance. Furthermore, according to the present invention, it is possible to provide a vulcanized rubber for tire treads, as well as a tire, that maintains good fuel efficiency while exhibiting excellent abrasion resistance and tear resistance.

Claims

1. A rubber composition containing a rubber component and carbon black, wherein the rubber component includes a diene rubber, and the rubber composition has a loss loss tangent (2% tanδ) of 0.095 or more and 0.195 or less at 2% strain, and a hysteresis loss (H) at 80°C and 200% elongation. ８０℃－２００％ ) is 0.095 or higher, (H ８０℃－２００％ A rubber composition characterized in that (2% tanδ) is 0.88 or higher.

2. The above (H ８０℃－２００％ The rubber composition according to claim 1, wherein the ratio of (2% tanδ) is 1.00 or less.

3. The rubber composition according to claim 1, wherein the rubber component includes a modified diene rubber.

4. The rubber composition according to claim 3, wherein the modifying group in the modified diene rubber has atoms other than carbon and hydrogen.

5. The rubber composition according to claim 4, wherein the modifying group in the modified diene rubber is one or more selected from nitrogen atoms, oxygen atoms, sulfur atoms, metalloid atoms, and metal atoms.

6. The rubber composition according to claim 1, wherein the rubber component includes isoprene-based rubber.

7. The rubber composition according to claim 6, wherein the isoprene-based rubber includes natural rubber.

8. The rubber composition according to claim 7, wherein the proportion of natural rubber in the rubber component is 50% by mass or more and 90% by mass or less.

9. The compressed sample has an oil absorption capacity (COAN) of 100–140 mL / 100 g and a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 100–135 m². ２ The rubber composition according to claim 1, wherein the carbon black content at a concentration of / g is 20 parts by mass or more per 100 parts by mass of the rubber component.

10. The compressed sample has an oil absorption capacity (COAN) of 70–105 mL / 100 g and a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 110–150 m². ２ The rubber composition according to claim 1, wherein the carbon black content at / g is 3 parts by mass or more and 20 parts by mass or less per 100 parts by mass of rubber component.

11. The compressed sample has an oil absorption capacity (COAN) of 80–110 mL / 100 g and a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 150–220 m². ２ The rubber composition according to claim 1, wherein the carbon black content at / g is 3 parts by mass or more and 20 parts by mass or less per 100 parts by mass of rubber component.

12. The specific surface area (CTAB) for cetyltrimethylammonium bromide adsorption is 180 m². ２ The rubber composition according to claim 1, further containing silica in an amount of 1g or more.

13. The CTAB is 180m ２ The rubber composition according to claim 12, wherein the silica content, which is 15 parts by mass or less per 100 parts by mass of the rubber component, is 15 parts by mass or less.

14. A vulcanized rubber for tire treads, characterized by being obtained by vulcanizing a rubber composition according to any one of claims 1 to 13.

15. A tire characterized by having the vulcanized rubber described in claim 14 provided in the tread portion.

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