Rubber composition and tire

Abstract

To provide a rubber composition which is excellent in wet grip performance, and has high strength and tensile product.SOLUTION: A rubber composition contains diene-based rubber, silica, and a silane-modified resin. The silane-modified resin is a resin having an alkoxysilyl group as a modified group, tensile elastic modulus of 700 to 1,200 MPa and a melting temperature Tm of 110 to 140°C, for example, silane-modified polyethylene is preferably used.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] It is known that a resin such as polyethylene is blended into a rubber composition containing a diene rubber. For example, Patent Document 1 describes a rubber composition having a density of 0.910 g / cm 3 More than 0.940g / cm 3 It is described that by compounding a low density polyethylene and carbon black of less than 1000 g / m² to a rubber composition, cut resistance and abrasion resistance can be improved.

[0003] Patent Document 2 describes that the cut resistance is improved by compounding an ethylene-vinyl acetate copolymer and carbon black into a rubber composition.

[0004] Patent Document 3 describes that by blending a silane-modified hydrocarbon resin obtained by modifying a hydrocarbon resin containing 20 to 70 mass% of 1,3-pentadiene monomer units, 10 to 35 mass% of alicyclic monoolefin monomer units having 4 to 6 carbon atoms, and 3 to 30 mass% of acyclic monoolefin monomer units having 4 to 8 carbon atoms with an organic silane compound into a rubber composition, it is possible to obtain excellent processability and an excellent balance between rolling resistance and wet grip performance in tire applications. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-14856 A [Patent Document 2] JP 2019-14857 A [Patent Document 3] International Publication No. 2017 / 170839 Summary of the Invention [Problem to be solved by the invention]

[0006] Compared to the elastic modulus of typical diene rubber, resins such as polyethylene have a high elastic modulus, so adding such a resin with a high elastic modulus increases the strength of the rubber composition. However, when the rubber composition is deformed, there is no interaction between the diene rubber as a matrix and the filler, so voids are generated, and it has been found that this results in a low modulus during deformation and a low tensile product because the voids become the breaking points.

[0007] On the other hand, the silica compounded in the rubber composition has a strong tendency to aggregate, and without the dispersing effect of a silane coupling agent, the tan δ at around 0° C. will be low, and the excellent wet grip performance will not be exhibited.

[0008] In view of the above, an object of an embodiment of the present invention is to provide a rubber composition that is excellent in wet grip performance, and also has high strength and a high tensile product. [Means for solving the problem]

[0009] The present invention includes the embodiments set forth below. [1] A rubber composition comprising a diene rubber, silica, and a silane-modified resin having an alkoxysilyl group as a modifying group, a tensile modulus of elasticity of 700 to 1200 MPa, and a melting temperature Tm of 110 to 140°C. [2] The rubber composition according to [1], wherein the silane-modified resin is a silane-modified polyethylene. [3] The rubber composition according to [1] or [2], wherein the amount of the silica is 30 to 150 parts by mass per 100 parts by mass of the diene rubber, and the amount of the silane-modified resin is 3 to 30 parts by mass per 100 parts by mass of the silica. [4] The rubber composition according to any one of [1] to [3], further comprising a silane coupling agent, wherein a mass ratio of the silane-modified resin to the silane coupling agent is 2 / 3 to 2 / 1. [5] A tire obtained by using the rubber composition according to any one of [1] to [4]. Effect of the Invention

[0010] According to an embodiment of the present invention, it is possible to provide a rubber composition that has excellent wet grip performance, high strength, and a high tensile product. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The rubber composition according to the present embodiment includes a diene rubber as a rubber component, silica as a reinforcing filler, and a silane-modified resin having a tensile modulus of 700 to 1200 MPa and a melting temperature Tm of 110 to 140°C. In general, the role of the silane compound in a rubber composition containing silica is, first, to improve the dispersibility of the silica by reacting with the silica surface to hydrophobize the silica. Such a rubber composition having high dispersibility of silica can increase tan δ around 0°C and improve wet grip performance. The role of the silane compound is, second, to improve the interaction between the dispersed silica and the diene rubber as a matrix. For example, a sulfide silane coupling agent, which is often used in rubber compositions for tires, increases the interaction between the silica and the matrix rubber by reacting the sulfide portion with the double bond portion of the diene rubber, thereby increasing the reinforcing property of the rubber composition. On the other hand, the silane-modified resin according to the present embodiment improves the dispersibility of the silica by reacting the alkoxysilyl group with the silica. Although the reactivity with diene rubber is low, the silica is in the form of a polymer as a resin, and has the above melting temperature, so that it is in a state of being melted into the matrix rubber. Therefore, the interaction between the silica and the matrix rubber can be increased to improve the reinforcing properties. Moreover, the strength of the rubber composition can be increased by adding a resin having a high elastic modulus as described above. Therefore, according to this embodiment, it is considered that a rubber composition having excellent wet grip performance due to the improved dispersibility of silica, as well as high strength and high tensile product can be obtained.

[0012] In this embodiment, the diene rubber refers to a rubber having a repeating unit corresponding to a diene monomer having a conjugated double bond, and contains a carbon-carbon double bond in the main chain of the polymer. Specific examples of the diene rubber include various diene rubbers that are usually used in rubber compositions, such as natural rubber (NR), synthetic isoprene rubber (IR), polybutadiene rubber (BR), styrene butadiene rubber (SBR), nitrile rubber (NBR), chloroprene rubber (CR), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, and styrene-isoprene-butadiene copolymer rubber. These diene rubbers also include those whose terminals or main chains are modified as necessary (for example, terminal-modified SBR), and those whose main chains are modified to impart desired properties (for example, modified NR). These diene rubbers may be used alone or in combination of two or more.

[0013] In one embodiment, the diene rubber may include styrene butadiene rubber. The styrene butadiene rubber may be solution polymerized styrene butadiene rubber (SSBR) or emulsion polymerized styrene butadiene rubber (ESBR). The styrene butadiene rubber may be modified styrene butadiene rubber (modified SBR) or unmodified styrene butadiene rubber (unmodified SBR).

[0014] More preferably, the diene rubber contains modified SBR (preferably modified SSBR) into which a functional group has been introduced. The functional group of the modified SBR preferably contains an oxygen atom and / or a nitrogen atom, and examples thereof include at least one selected from the group consisting of an amino group, a hydroxyl group, an alkoxy group, an epoxy group, a silyl group, and a carboxyl group. By containing modified SBR modified with such a functional group, the dispersibility of silica as a filler can be improved.

[0015] In one embodiment, the amount of styrene butadiene rubber (preferably modified styrene butadiene rubber) in 100 parts by mass of diene rubber is not particularly limited, but is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and even more preferably 80 parts by mass or more, and may be 100 parts by mass.

[0016] In the present embodiment, examples of silica include wet silica and dry silica. It is preferable to use wet silica such as wet precipitation silica and wet gelation silica.

[0017] The amount of silica is preferably 30 to 150 parts by mass, more preferably 35 to 120 parts by mass, more preferably 40 to 100 parts by mass, and further preferably 45 to 80 parts by mass, based on 100 parts by mass of the diene rubber.

[0018] The reinforcing filler to be blended in the rubber composition may be silica alone, or may be blended with silica and carbon black. The reinforcing filler preferably contains 80% by mass or more of silica, more preferably 90% by mass or more. The content of carbon black is not particularly limited, and may be 15 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less, or 0 parts by mass, relative to 100 parts by mass of the diene rubber.

[0019] In this embodiment, as the silane-modified resin, a thermoplastic resin having an alkoxysilyl group as a modifying group, a tensile modulus of elasticity of 700 to 1200 MPa, and a melting temperature Tm of 110 to 140° C. is used.

[0020] In the case of the silane-modified resin, the alkoxysilyl group reacts with the silanol group on the surface of silica, thereby improving the dispersibility of silica.As the alkoxysilyl group, for example, the trialkoxysilyl group such as trimethoxysilyl group, triethoxysilyl group, alkyl dialkoxysilyl group such as methyl dimethoxysilyl group, ethyl diethoxysilyl group, dialkyl alkoxysilyl group such as dimethyl methoxysilyl group, diethyl ethoxysilyl group, etc., these may contain one kind or two or more kinds.Among these, the trialkoxysilyl group is preferred.

[0021] The silane-modified resin having an alkoxysilyl group as a modifying group may be obtained by, for example, grafting an alkoxysilane (for example, vinylalkoxysilane) into a base resin to modify it with silane, or may be obtained by randomly copolymerizing the monomer of the base resin with vinylalkoxysilane. The method of silane modification by grafting can be carried out according to a known method, for example, solution modification, melt modification, solid-phase modification by irradiation with electron beam or ionizing radiation, modification in supercritical fluid, etc.

[0022] The alkoxysilyl group may be introduced at the terminal of the base resin, but is preferably introduced randomly into the main chain by the above-mentioned graft introduction or random copolymerization.

[0023] The tensile modulus of the silane-modified resin is 700 MPa or more, thereby enabling the reinforcing effect to be enhanced. The tensile modulus of the silane-modified resin is more preferably 720 to 1100 MPa, more preferably 750 to 1000 MPa, and further preferably 770 to 900 MPa.

[0024] In this specification, the tensile modulus of elasticity of the silane-modified resin is the tensile modulus of elasticity Et measured in accordance with JIS K7161-1:2014, and refers to the slope of the stress / strain curve corresponding to two strain points of ε1 = 0.05% and ε2 = 0.25%. In detail, it is measured by performing a tensile test using a test piece having a thickness of 4 mm and a width of 10 mm, with a gauge length of 50 mm, a grip distance of 115 mm, and a test speed of 1 mm / min.

[0025] The melting temperature Tm of the silane-modified resin is 140°C or lower, so that the resin can be mixed with the diene rubber that melts during kneading of the rubber composition to become the matrix. The melting temperature Tm is 110°C or higher, so that the strength reduction during use of the rubber composition after vulcanization can be suppressed. The melting temperature Tm of the silane-modified resin is more preferably higher than 110°C and 135°C or lower, and further preferably 115 to 130°C.

[0026] In this specification, the melting temperature Tm of the silane-modified resin is the melting peak temperature (Tpm) measured according to JIS K7121-1987, that is, the temperature at the apex of the melting peak. In detail, in differential scanning calorimetry (heat flux method DSC), the sample was heated from -80°C to 250°C at a rate of 10°C / min to obtain a DSC curve, from which the melting peak temperature was determined. When two or more melting peaks appear, the temperature is taken to be the apex temperature of the highest melting peak.

[0027] The base resin for the silane-modified resin is not particularly limited as long as it is a polymer that gives the tensile modulus and melting temperature Tm of the silane-modified resin in the above-mentioned numerical ranges, and examples thereof include polyethylene and terpene resins.

[0028] Terpene resins are resins obtained by polymerizing terpene monomers such as α-pinene, β-pinene, limonene, and dipentene. Examples of terpene resins include polyterpene resins produced using only terpene monomers, as well as terpene phenol resins and aromatic modified terpene resins.

[0029] The base resin of the silane-modified resin is preferably polyethylene. That is, the silane-modified resin according to a preferred embodiment is silane-modified polyethylene. As the silane-modified polyethylene, for example, it is preferable to use Linkron (registered trademark), which is a silane crosslinkable resin sold by Mitsubishi Chemical Corporation. Specific examples include "Linkron SH710N", "Linkron SL800N", "Linkron SS732N", "Linkron CF700N", "Linkron XCF710N", "Linkron XLE830N", "Linkron LE760N", "Linkron XHE740N", "Linkron HM600A", etc.

[0030] The density of the silane-modified polyethylene is not particularly limited and is, for example, 0.85 to 0.96 g / cm 3 may be used, but preferably 0.85 to 0.93 g / cm 3 and more preferably 0.86 to 0.89 g / cm 3 Here, the density is measured in accordance with JIS K7112:1999.

[0031] The amount of the silane-modified resin (preferably silane-modified polyethylene) is preferably 3 to 30 parts by mass, more preferably 5 to 25 parts by mass, and further preferably 6 to 20 parts by mass, relative to 100 parts by mass of the silica. The amount of the silane-modified resin relative to 100 parts by mass of the diene rubber is not particularly limited, and may be, for example, 0.5 to 30 parts by mass, 1 to 20 parts by mass, or 2 to 15 parts by mass.

[0032] The rubber composition according to the present embodiment may further contain a silane coupling agent. By compounding the silane coupling agent together with the silane-modified resin, the wet grip performance can be further improved. In this case, the amount of the silane coupling agent is not particularly limited, but is preferably 3 to 20 parts by mass, more preferably 4 to 15 parts by mass, and further preferably 5 to 12 parts by mass, relative to 100 parts by mass of silica.

[0033] From the viewpoint of the balance between wet grip performance, strength and tensile product, the mass ratio of the silane-modified resin to the silane coupling agent (amount of silane-modified resin / amount of silane coupling agent) is preferably 2 / 3 to 2 / 1, and more preferably 2 / 3 to 4 / 3.

[0034] Examples of the silane coupling agent include sulfide silane coupling agents such as bis(3-triethoxysilylpropyl) tetrasulfide, bis(3-triethoxysilylpropyl) disulfide, bis(2-triethoxysilylethyl) tetrasulfide, bis(4-triethoxysilylbutyl) disulfide, bis(3-trimethoxysilylpropyl) tetrasulfide, and bis(2-trimethoxysilylethyl) disulfide; 3-mercaptopropyltrimethoxysilane; Examples of the silane coupling agents include mercaptosilane coupling agents such as mercaptotriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyldimethylmethoxysilane, and mercaptoethyltriethoxysilane, and thioester group-containing silane coupling agents such as 3-octanoylthio-1-propyltriethoxysilane, 3-propionylthiopropyltrimethoxysilane, 3-hexanoylthio-1-propyltriethoxysilane, and 3-octanoylthio-1-propyltrimethoxysilane. These can be used alone or in combination of two or more.

[0035] In addition to the above components, the rubber composition according to the present embodiment may contain, as optional components, various additives that are generally used in rubber compositions, such as zinc oxide, stearic acid, oil, an antioxidant, wax, a vulcanizing agent, and a vulcanization accelerator.

[0036] The content of zinc oxide is not particularly limited, and may be, for example, 0 to 10 parts by mass, 0.5 to 5 parts by mass, or 1 to 4 parts by mass relative to 100 parts by mass of the diene rubber.

[0037] The content of stearic acid is not particularly limited, and may be, for example, 0 to 10 parts by mass, 0.5 to 5 parts by mass, or 1 to 4 parts by mass relative to 100 parts by mass of the diene rubber.

[0038] The content of the oil is not particularly limited, and may be, for example, 0 to 40 parts by mass, 5 to 35 parts by mass, or 10 to 30 parts by mass relative to 100 parts by mass of the diene rubber.

[0039] Examples of the antiaging agent include various antiaging agents such as amine-ketone type, aromatic secondary amine type, monophenol type, bisphenol type, and benzimidazole type, and any one or more of them can be used in combination. The content of the antiaging agent is not particularly limited, and may be, for example, 0 to 10 parts by mass, 0.5 to 5 parts by mass, or 1 to 4 parts by mass relative to 100 parts by mass of the diene rubber.

[0040] The content of the wax is not particularly limited, and may be, for example, 0 to 10 parts by mass, 0.5 to 5 parts by mass, or 1 to 4 parts by mass relative to 100 parts by mass of the diene rubber.

[0041] As the vulcanizing agent, sulfur is preferably used. The content of the vulcanizing agent is not particularly limited, but may be 0.1 to 10 parts by mass, 0.5 to 5 parts by mass, or 1 to 3 parts by mass, based on 100 parts by mass of the diene rubber.

[0042] Examples of the vulcanization accelerator include various vulcanization accelerators such as sulfenamide-based, guanidine-based, thiuram-based, and thiazole-based, and any one of them can be used alone or in combination of two or more. The content of the vulcanization accelerator is not particularly limited, but is preferably 0.1 to 7 parts by mass, more preferably 0.5 to 5 parts by mass, and may be 1 to 4 parts by mass, relative to 100 parts by mass of the diene rubber.

[0043] The rubber composition according to the present embodiment can be prepared by kneading in a conventional manner using a mixer such as a Banbury mixer, a kneader, or a roll. That is, for example, in the first mixing stage (non-pro kneading step), additives other than the vulcanizing agent and the vulcanization accelerator are added and mixed with the diene rubber together with silica and the silane-modified resin. Next, in the final mixing stage (pro kneading step), the vulcanizing agent and the vulcanization accelerator are added and mixed to the obtained mixture. This makes it possible to prepare an unvulcanized rubber composition. In the non-pro kneading step, in order to melt the silane-modified resin, the discharge temperature from the mixer is preferably 140°C or higher, more preferably 150 to 170°C.

[0044] The rubber composition according to the present embodiment can be used for various rubber members such as tires, anti-vibration rubber, and conveyor belts. It is preferably for tires, and can be applied to various parts of tires such as treads, sidewalls, and beads of pneumatic tires of various sizes for various purposes such as tires for passenger cars and large tires for trucks and buses. It is more preferably used in tire treads. That is, a tire according to one embodiment includes a tread rubber formed from the above rubber composition.

[0045] In one embodiment, a tire including a rubber portion (e.g., tread rubber, sidewall rubber, etc.) made of the rubber composition is manufactured as follows. The rubber composition is molded into a predetermined shape by a conventional method, for example, extrusion processing. A green tire is manufactured by combining the obtained molded product with other parts. A pneumatic tire can be manufactured by vulcanizing the green tire at, for example, 140 to 180°C. EXAMPLES

[0046] Examples will be shown below, but the present invention is not limited to these examples.

[0047] Details of the raw materials used in the examples and comparative examples are as follows. SBR: Terminal amine modified SSBR, "HPR350" manufactured by ENEOS Material Co., Ltd. Silica: "Nipsil AQ" manufactured by Tosoh Silica Corporation Zinc oxide: "Zinc oxide No. 3" manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: Kao Corporation's "Lunac S-20" Oil: JX Nippon Oil & Energy Corporation "Process NC-140" Sulfur: "Powdered sulfur" manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator 1: "Soxinol CZ" manufactured by Sumitomo Chemical Co., Ltd. Vulcanization accelerator 2: "Noccelaer D" manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0048] Silane coupling agent: Bis(3-triethoxysilylpropyl) disulfide, "Si75" manufactured by Evonik Japan Co., Ltd. Propyltriethoxysilane: manufactured by Tokyo Chemical Industry Co., Ltd. PE: Unmodified polyethylene, Ube Maruzen Polyethylene Co., Ltd. "Yumerit 0520F" (tensile modulus = 870 MPa, melting temperature Tm = 111°C) Silane-modified BR: Silane-modified liquid butadiene rubber, Kuraray Co., Ltd. "GS-L-BR-114" Silane-modified PP: Silane-modified polypropylene, Mitsubishi Chemical Corporation's "Linklon PK500N" (tensile modulus = 1200 MPa, melting temperature Tm = 210°C) Silane-modified PE1: Triethoxysilyl-modified polyethylene, Mitsubishi Chemical Corporation's "Linklon SH710N" (density = 0.89 g / cm 3 , tensile modulus = 840MPa, melting temperature Tm = 120℃) Silane-modified PE2: Triethoxysilyl-modified polyethylene, Mitsubishi Chemical Corporation's "Linklon SL800N" (density = 0.87 g / cm 3 , tensile modulus = 800MPa, melting temperature Tm = 120℃)

[0049] The evaluation methods in the examples and comparative examples are as follows. (1)S100 and tensile product: A tensile test (dumbbell-shaped No. 3) was carried out on a 2 mm thick vulcanized rubber sample using an autograph manufactured by Shimadzu Corporation in accordance with JIS K6251:2017 to measure the tensile strength (tensile speed = 500 mm / min).

[0050] The tensile stress S100 at 100% elongation was then determined, and the values ​​for Comparative Example 1 in Table 1, Comparative Example 5 in Table 2, Comparative Example 7 in Table 3, Comparative Example 8 in Table 4, Comparative Example 12 in Table 5, and Comparative Example 14 in Table 6 were each shown as an index set to 100. A larger index indicates a larger S100 and higher reinforcing properties.

[0051] In addition, the tensile strength at break Tb (MPa) and elongation at break Eb (%) were determined to calculate the tensile product (Tb × Eb ÷ 100), and the values ​​for Comparative Example 1 in Table 1, Comparative Example 5 in Table 2, Comparative Example 7 in Table 3, Comparative Example 8 in Table 4, Comparative Example 12 in Table 5, and Comparative Example 14 in Table 6 were each shown as an index set to 100. A larger index indicates a larger tensile product value and higher durability.

[0052] (2) 0℃ tan δ: A viscoelasticity test was performed in a tensile mode on a vulcanized rubber sample having a thickness of 2 mm, using a viscoelasticity tester manufactured by Ueshima Seisakusho Co., Ltd., at a frequency of 10 Hz, a static strain of 10%, a dynamic strain of 1%, and a temperature of 0°C, to measure the loss factor tan δ. The tan δ of Comparative Example 1 in Table 1, the tan δ of Comparative Example 5 in Table 2, the tan δ of Comparative Example 7 in Table 3, the tan δ of Comparative Example 8 in Table 4, the tan δ of Comparative Example 12 in Table 5, and the tan δ of Comparative Example 14 in Table 6 are each shown as an index with 100 as the index. The larger the index, the larger the tan δ, i.e., the larger the energy loss, which indicates that the tire has excellent wet grip performance.

[0053] [First Experimental Example] According to the formulation (parts by mass) shown in Table 1 below, diene rubber was masticated for 30 seconds using a Daihan lab mixer (300cc), and then the components excluding sulfur and vulcanization accelerator were added and kneaded for 240 seconds, and then discharged (discharge temperature = 170 ° C). Next, the discharged rubber composition was added to the lab mixer, kneaded for 180 seconds, and then discharged (discharge temperature = 165 ° C). Furthermore, the discharged rubber composition, sulfur, and vulcanization accelerator were added to the lab mixer and kneaded for 60 seconds (discharge temperature = 105 ° C) to prepare the unvulcanized rubber compositions of Comparative Examples 1 to 4 and Examples 1 and 2. The obtained rubber composition was sheeted using two rolls to a thickness of 2 mm, and then vulcanization press was performed at 160 ° C for 20 minutes to obtain a vulcanized rubber sample. The obtained vulcanized rubber sample was evaluated for S100, tensile product, and 0 ° C tan δ.

[0054] The results are shown in Table 1. Comparative Example 1 is an example in which a low molecular weight silane was used as a silica dispersant, and the 0°C tan δ was high due to improved dispersibility, and the wet grip performance was excellent, but the tensile stress S100 and tensile product were low.

[0055] Comparative Example 2 is an example in which PE, i.e., polyethylene not modified with silane, was blended. In this case, since polyethylene is harder than diene rubber, the tensile stress S100 was improved, but the tensile product and 0°C tan δ were reduced.

[0056] Comparative Example 3 is an example in which silane-modified BR was blended. Silane-modified BR is a liquid rubber at room temperature, so its melting temperature Tm is lower than room temperature, and it does not retain its original shape, so its tensile modulus cannot be measured. In Comparative Example 3, the flexibility and low-temperature properties specific to butadiene rubber are excellent, so the tensile product is large and the 0°C tan δ is also good, but the original modulus of elasticity is lower than that of the matrix rubber, so the tensile stress S100 is lower than that of Comparative Example 1, and the reinforcing properties are poor.

[0057] Comparative Example 4 is an example in which silane-modified PP was blended. The silane-modified PP has a high melting temperature and does not melt when kneaded with the diene rubber, remaining as raw material pellets, so it was not possible to produce a uniform rubber sheet. Therefore, the above physical property measurements and evaluations were not performed.

[0058] In contrast, Examples 1 and 2, which used silane-modified PE1 and 2 having predetermined tensile modulus and melting temperature Tm, had the same or better 0°C tan δ (wet grip performance) as Comparative Example 1, while improving the tensile stress S100 and tensile product, and were excellent in reinforcement and durability.

[0059] [Table 1]

[0060] [Second Experimental Example] Rubber compositions of Comparative Examples 5 and 6 and Example 3 were prepared in the same manner as in the first experimental example, according to the formulation (parts by mass) shown in Table 2 below. The obtained rubber compositions were used to prepare vulcanized rubber samples, and S100, tensile product, and 0°C tan δ were evaluated.

[0061] The results are shown in Table 2 below. Even if the amount of the silane compound was increased, the same effect as in the first experimental example was confirmed. That is, in Comparative Example 6, which used PE not modified with silane, the tensile stress S100 was improved compared to Comparative Example 5, which used a low molecular weight silane, but the 0°C tan δ was decreased. In contrast, in Example 3, which used silane-modified PE, the tensile stress S100 and tensile product were significantly improved while the excellent 0°C tan δ (wet grip performance) was further improved compared to Comparative Example 5, and the reinforcement and durability were excellent.

[0062] [Table 2]

[0063] [Third Experimental Example] Rubber compositions of Comparative Example 7 and Example 4 were prepared in the same manner as in the first experimental example, according to the formulation (parts by mass) shown in Table 3 below. The obtained rubber compositions were used to prepare vulcanized rubber samples, and S100, tensile product, and 0°C tan δ were evaluated.

[0064] The results are shown in Table 3. When the amount of silica was reduced to 30 parts by mass, the effect was reduced, but Example 4, which used silane-modified PE, had improved tensile stress S100 and tensile product while maintaining or improving excellent 0°C tan δ (wet grip performance), compared to Comparative Example 7, which used a low molecular weight silane.

[0065] [Table 3]

[0066] [Fourth Experimental Example] Rubber compositions of Comparative Examples 8 to 11 and Examples 5 and 6 were prepared in the same manner as in the first experimental example according to the formulation (parts by mass) shown in Table 4 below. The obtained rubber compositions were used to prepare vulcanized rubber samples, and S100, tensile product, and 0°C tan δ were evaluated.

[0067] The results are shown in Table 4 below. Even when the amount of silica was increased to 75 parts by mass, the same effect as in the first experimental example was confirmed. That is, in Comparative Example 9, which used PE not modified with silane, the tensile stress S100 was improved, but the tensile product and 0°C tan δ were decreased, compared to Comparative Example 8, which used a low molecular weight silane. In Comparative Example 10, which was compounded with silane-modified BR, the tensile product and 0°C tan δ were improved, but the tensile stress S100 was decreased, and the reinforcement was poor. In Comparative Example 11, which was compounded with silane-modified PP, a uniform rubber sheet could not be produced. In contrast, in Examples 5 and 6, which used silane-modified PE1 and 2, the tensile stress S100 and tensile product were improved while the excellent 0°C tan δ (wet grip performance) was further improved compared to Comparative Example 8, and the reinforcement and durability were excellent.

[0068] [Table 4]

[0069] [Fifth Experimental Example] Rubber compositions of Comparative Examples 12 and 13 and Examples 7 and 8 were prepared in the same manner as in the first experimental example, according to the formulation (parts by mass) shown in Table 5 below. The rubber compositions obtained were used to prepare vulcanized rubber samples, and S100, tensile product, and 0°C tan δ were evaluated.

[0070] The results are shown in Table 5 below. The same effect as in the first experimental example was confirmed in the system in which a silane coupling agent was used in combination. That is, in Comparative Example 13 in which a non-silane-modified PE was used in combination with a silane coupling agent, the tensile stress S100 was improved, but the tensile product and 0°C tan δ were reduced, compared to Comparative Example 12 in which a low molecular weight silane was used in combination with a silane coupling agent. In contrast, in Examples 7 and 8 in which silane-modified PE1 and 2 were used in combination with a silane coupling agent, the tensile stress S100 and tensile product were improved while maintaining the excellent 0°C tan δ (wet grip performance) compared to Comparative Example 12, and the reinforcement and durability were excellent.

[0071] [Table 5]

[0072] [Experimental Example 6] According to the formulation (parts by mass) shown in Table 6 below, and otherwise in the same manner as in the first experimental example, the rubber compositions of Comparative Example 14 and Examples 9 to 12 were prepared, and the obtained rubber compositions were used to prepare vulcanized rubber samples, and S100, tensile product, and 0°C tan δ were evaluated.

[0073] The results are shown in Table 6 below. In Examples 9 to 12, the mass ratio of the silane coupling agent and silane-modified PE1 and 2 was changed in a system in which the silane coupling agent and silane-modified PE1 and 2 were used in combination. In Examples 9 to 12, the tensile stress S100 and tensile product were improved while improving 0°C tan δ (wet grip performance) compared to Comparative Example 14 in which no silane-modified PE was blended. In particular, Examples 9 and 10, which had a high mass ratio of silane-modified PE, showed a high improvement effect on tensile stress, and Examples 11 and 12, which had a high mass ratio of silane coupling agent, showed a high improvement effect on tensile product and 0°C tan δ.

[0074] [Table 6]

[0075] In addition, the various numerical ranges described in the specification can be arbitrarily combined with their upper and lower limits, and all such combinations are considered to be preferred numerical ranges described in the specification. In addition, a numerical range described as "X to Y" means from X to Y.

Claims

1. Diene rubber, Silica, and a silane-modified resin having an alkoxysilyl group as a modifying group, a tensile modulus of elasticity of 700 to 1200 MPa, and a melting temperature Tm of 110 to 140° C.; A rubber composition comprising:

2. The rubber composition according to claim 1 , wherein the silane-modified resin is a silane-modified polyethylene.

3. The amount of the silica is 30 to 150 parts by mass per 100 parts by mass of the diene rubber, and the amount of the silane-modified resin is 3 to 30 parts by mass per 100 parts by mass of the silica.

4. The rubber composition according to claim 1, further comprising a silane coupling agent, wherein a mass ratio of the silane-modified resin to the silane coupling agent is from 2 / 3 to 2 / 1.

5. A tire obtained by using the rubber composition according to any one of claims 1 to 4.

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