Tire

Abstract

To provide a tire capable of achieving both wear resistance and workability in manufacturing the tire.SOLUTION: The tire 1 includes a pair of bead parts 3, a pair of sidewall parts 4, and a tread part 2 continuing to both sidewall parts 4, and the tread part 2 is divided into at least three parts by a center part 9 including a tire equatorial plane 11 and a pair of shoulder parts 10 including tread ends 12 in the tire width direction. In the tire 1, the tread rubber 7 of the center portion is made of a rubber composition containing at least a rubber ingredient, a filler, and a softener, the rubber ingredient contains at least one selected from styrene-butadiene rubber and butadiene rubber, the softener contains resins, and the resins include C5 resins and C5C9 resins.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire. [Background technology]

[0002] Conventionally, in the field of motorcycle tire treads, a method has been developed in which the tread is divided into three parts in the tire width direction and two types of tread rubber are used to achieve a certain degree of compatibility between the performance required for straight-line driving and the performance required for cornering.

[0003] For example, Patent Document 1 discloses a motorcycle tire having a pair of bead portions, a pair of sidewall portions, and a tread portion connected to both sidewall portions, the tread portion being divided into three portions in the tire width direction by a center portion including the tire equatorial plane and a pair of shoulder portions including the tread ends, in which the tread rubber of the center portion and the tread rubber of the shoulder portions both contain a rubber component including a styrene-butadiene rubber and a modified conjugated diene polymer, and silica, and contains 40 to 120 parts by mass of a filler per 100 parts by mass of the rubber component, and the silica content of the filler is 80% by mass or more. Patent Document 2 also discloses a rubber composition for tires that includes a rubber component, a filler, and a softener, wherein the rubber component includes at least one selected from styrene-butadiene rubber and butadiene rubber, the filler includes silica and carbon black, and the total content of the silica and the carbon black is 65 to 140 parts by mass per 100 parts by mass of the rubber component, and the softener includes a liquid softener component and a hydrogenated resin, and the proportion of the hydrogenated resin in the total content of the softener is 40 mass% or more, and the hydrogenated resin has a softening point exceeding 110°C and a weight average molecular weight in terms of polystyrene of 200 to 1600 g / mol. The rubber composition for tires and a tire that includes such a rubber composition are also disclosed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 204236 [Patent Document 2] Japanese Patent Publication No. 2022-187976 Summary of the Invention [Problem to be solved by the invention]

[0005] The above Patent Document 1 aims to provide a tire having excellent wet grip performance and wear resistance of the tread, while the above Patent Document 2 aims to provide a tire that achieves both good tire grip performance and ease of manufacturing. However, although tires are also required to have both wear resistance and ease of work during tire manufacturing, no studies have been conducted on tires that can achieve both of these properties. Therefore, there is a demand for tires that can achieve both wear resistance and ease of work during tire manufacturing.

[0006] Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional technology and to provide a tire that can achieve both wear resistance and workability during tire manufacturing. [Means for solving the problem]

[0007] The gist of the tire of the present invention that solves the above problems is as follows.

[0008] [1] A tire having a pair of bead portions, a pair of sidewall portions, and a tread portion connected to both sidewall portions, the tread portion being divided into at least three portions in the tire width direction by a center portion including the tire equatorial plane and a pair of shoulder portions including the tread edges, the tread rubber of the center portion is made of a rubber composition containing at least a rubber component, a filler, and a softener, the rubber component contains at least one selected from styrene-butadiene rubber and butadiene rubber, The tire, wherein the softener contains a resin, and the resin contains a C5-based resin and a C5C9-based resin. The tire described in the above [1] achieves both wear resistance and workability during tire production.

[0009] [2] The tire according to [1], wherein the filler contains 70 parts by mass or more of silica per 100 parts by mass of the rubber component. The tire described in [2] above has both excellent wear resistance and workability during tire production.

[0010] [3] The tire according to [1] or [2], wherein the filler contains carbon black. The tire described in [3] above has improved wear resistance.

[0011] [4] The tire according to any one of [1] to [3], wherein the amount of the resin is 10 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the rubber component. The tire described in [4] above can achieve both high wear resistance and high workability during tire production.

[0012] [5] The tire according to any one of [1] to [4], wherein the softener further contains a liquid plasticizer. The tire described in [5] above has improved workability.

[0013] [6] The tire according to any one of [1] to [5], wherein the content of the softener is 40 parts by mass or more per 100 parts by mass of the rubber component. The tire described in [6] above can achieve both high wear resistance and high workability during tire production.

[0014] [7] The tire according to any one of [1] to [6], wherein the rubber component contains a styrene-butadiene rubber and a butadiene rubber. The tire described in [7] above can achieve both high wear resistance and high workability during tire production.

[0015] [8] The tire according to any one of [1] to [7], wherein the ratio of the storage modulus at 60°C of the tread rubber of the center portion to the storage modulus at 60°C of the tread rubber of the shoulder portions exceeds 1.72. The tire described in [8] above can achieve both high wear resistance and high workability during tire production.

[0016] [9] The tire according to any one of [1] to [8], which is for a motorcycle. Tires for motorcycles require wear resistance and also require ease of work during tire manufacturing, so the tire of this embodiment is suitable. [Effects of the Invention]

[0017] According to the present invention, it is possible to provide a tire that can achieve both wear resistance and workability during tire production. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic cross-sectional view showing an example of a tire of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The tire of the present invention will be described in detail below by way of example based on an embodiment thereof.

[0020] <Definition> The compounds described herein may be derived in part or in whole from fossil sources, biological sources such as plant sources, recycled sources such as used tires, or a mixture of two or more of fossil, biological, and recycled sources.

[0021] In the present invention, the extender oil contained in the rubber component is included in the softener.

[0022] <Tires> The tire of this embodiment is A tire comprising a pair of bead portions, a pair of sidewall portions, and a tread portion connected to both sidewall portions, the tread portion being divided into at least three portions in the tire width direction by a center portion including the tire equatorial plane and a pair of shoulder portions including tread edges, The tread rubber of the center portion is made of a rubber composition containing at least a rubber component, a filler, and a softener, The rubber component contains at least one selected from styrene-butadiene rubber and butadiene rubber, The softener contains a resin, and the resin contains a C5 resin and a C5C9 resin. The tire has both good abrasion resistance and good workability during tire production.

[0023] The rubber composition in the tread rubber of the center portion contains at least one rubber component selected from styrene-butadiene rubber and butadiene rubber, and thus has sufficient breaking properties. Furthermore, the rubber composition of the tread rubber in the center portion contains a filler, which improves the abrasion resistance. Furthermore, when the rubber composition in the tread rubber of the center portion contains both a C5 resin and a C5C9 resin, the C5 resin acts as an incompatible component with the polymer and is more likely to migrate to the surface. Therefore, the tire of this embodiment can achieve both wear resistance and workability during tire production.

[0024] (Tire structure) First, the structure of the tire of this embodiment will be described with reference to FIG. The tire 1 of this embodiment comprises a pair of bead portions 3, a pair of sidewall portions 4, and a tread portion 2 connected to both sidewall portions 4, and the tread portion 2 is divided into at least three portions in the tire width direction by a center portion 9 including the tire equatorial plane 11 and a pair of shoulder portions 10 including the tread ends 12.

[0025] Each bead portion 3 normally has a bead core 5, and one or more carcass layers 6 are provided so as to extend in a toroidal shape between the pair of bead cores 5. The carcass layer 6 is made of a plurality of carcass cords coated with rubber.

[0026] The sidewall portion 4 extends radially outward from the bead portion 3 on the side surface of the tire to reinforce and protect the side surface.

[0027] The tread portion 2 extends across both sidewall portions 4 . In the tire 1 of this embodiment, the tread portion 2 uses a divided tread that is divided into a center portion 9 and two shoulder portions 10 that sandwich the center portion 9. In the divided tread, the tread portion 2 is divided into at least three portions by the center portion 9 that includes the tire equatorial plane 11 and a pair of shoulder portions 10 that include a tread edge 12. The divided tread may have an additional portion between the center portion 9 and the shoulder portion 10, or the center portion 9 may be divided into multiple portions. For example, the tread portion 2 may be divided into the center portion 9 and the shoulder portions 10 in order from the tread edge 12, such as a first shoulder portion, a second shoulder portion, a first center portion, a second center portion, a third shoulder portion, and a fourth shoulder portion. The divided tread is preferably divided into three sections by a center section 9 and a pair of shoulder sections 10 . The tire equator is a latitude line of the tire that passes through the center of the tire in the width direction, and the surface in the tire circumferential direction that includes the tire equator is called the tire equatorial plane 11.

[0028] More specifically, the center portion 9 has a widthwise curved length (L C ) is the maximum length of the curved line in the width direction of the entire tread surface (L T (=L c +L s +L s The widthwise curve length (L C) is the maximum length of the curved line in the width direction of the entire tread surface (L T ) is 30% to 60%, wear resistance can be ensured.

[0029] The widthwise curve length (L S ) may be different between one shoulder portion 10 and the other shoulder portion 10, but it is usually preferable that they are the same, and the curve length in the width direction of the shoulder portion 10 (one side) is L T It is preferable that the value is (100-Lc) / 2% of the above.

[0030] Hereinafter, the rubber constituting the tread portion 2 may be referred to as tread rubber. Also, the tread rubber 8 in the shoulder portion is the rubber constituting the shoulder portion and may be simply referred to as "shoulder rubber." The tread rubber 7 in the center portion is the rubber constituting the center portion and may be simply referred to as "center rubber."

[0031] (tread rubber) In the tire of this embodiment, the tread rubber in the center portion is made of a rubber composition containing at least a rubber component, a filler, and a softener.

[0032] In the tire of this embodiment, the storage modulus of the tread rubber in the center portion at 60°C is preferably 12 MPa or more, more preferably 13 MPa or more, from the viewpoint of abrasion resistance, and is preferably 15 MPa or less, more preferably 14 MPa or less, from the viewpoint of steering stability.

[0033] In addition, in the tire of this embodiment, the storage modulus of the tread rubber in the shoulder portion at 60°C is preferably 5.0 MPa or more, more preferably 7.0 MPa or more, from the viewpoint of abrasion resistance, and is preferably 10 MPa or less, more preferably 8.0 MPa or less, from the viewpoint of steering stability.

[0034] The storage modulus of the center tread rubber and the shoulder tread rubber at 60°C can be measured using a viscoelasticity measuring device under conditions of 60°C, strain of 1.0%, and frequency of 52 Hz.

[0035] In the tire of this embodiment, the ratio of the storage modulus of the center portion tread rubber at 60°C to the storage modulus of the tread rubber of the shoulder portions (storage modulus of tread rubber of center portion / storage modulus of tread rubber of shoulder portions) preferably exceeds 1.72. When the ratio of the storage modulus of the center portion tread rubber at 60°C to the storage modulus of the tread rubber of the shoulder portions exceeds 1.72, the tire achieves both high levels of wear resistance and workability. From the same viewpoint, the ratio of the storage modulus of the center portion tread rubber at 60°C to the storage modulus of the tread rubber of the shoulder portions is more preferably 1.75 or greater, and even more preferably 1.8 or greater.

[0036] (Rubber composition) In the tire of this embodiment, the rubber composition constituting the tread rubber of the center portion contains at least a rubber component, a filler, and a softener, The rubber component contains at least one selected from styrene-butadiene rubber and butadiene rubber, The softener includes a resin, and the resin includes a C5-based resin and a C5C9-based resin. Each component contained in the rubber composition will be described below.

[0037] [Rubber component] The rubber component of the tread rubber in the center portion contains at least one selected from styrene-butadiene rubber (SBR) and butadiene rubber (BR). The rubber component preferably contains both styrene-butadiene rubber and butadiene rubber. Styrene-butadiene rubber and butadiene rubber are relatively difficult to adhere to each other and have excellent fracture properties.

[0038] The rubber component may be unmodified or modified, or may be a blend of unmodified and modified rubbers.

[0039] In the rubber component, the total proportion of styrene-butadiene rubber (SBR) and butadiene rubber (BR) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and may be 100% by mass.

[0040] -Styrene-butadiene rubber- The rubber component preferably contains styrene-butadiene rubber (SBR). From the viewpoint of improving handling stability, the rubber component preferably contains 50 parts by mass or more, more preferably 60 parts by mass or more, and even more preferably 65 parts by mass or more of styrene-butadiene rubber per 100 parts by mass of the rubber component. Also, from the viewpoint of improving abrasion resistance, the rubber component preferably contains 90 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 70 parts by mass or less of styrene-butadiene rubber per 100 parts by mass of the rubber component.

[0041] The styrene-butadiene rubber preferably has a styrene content of 5 to 50% by mass, more preferably 8 to 45% by mass. If the styrene content of the styrene-butadiene rubber is 5% by mass or more, the abrasion resistance of the rubber composition is further improved. The styrene unit can be determined by an infrared method (Morello method).

[0042] -Butadiene rubber- From the viewpoint of improving abrasion resistance, the rubber component preferably contains 10 parts by mass or more, more preferably 20 parts by mass or more, and even more preferably 30 parts by mass or more of butadiene rubber per 100 parts by mass of the rubber component. Also, from the viewpoint of improving handling stability, the rubber component preferably contains 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less of styrene-butadiene rubber per 100 parts by mass of the rubber component.

[0043] -Other rubber- The rubber component may contain other rubbers in addition to the styrene-butadiene rubber and butadiene rubber. The content of the other rubbers in the rubber component is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and may even be 0% by mass. Examples of such other rubbers include natural rubber (NR), isoprene rubber (IR), chloroprene rubber (CR), styrene-isoprene rubber (SIR), acrylonitrile-butadiene rubber (NBR), butyl rubber (IIR), and halogenated butyl rubber. These other rubbers may be used alone or in combination of two or more.

[0044] The rubber component may be partially or entirely oil-extended. When the rubber component is oil-extended, the extender oil is classified as a softener, which will be described later, and the amount of the extender oil is included as part of the amount of the softener.

[0045] [Filler] The rubber composition constituting the tread rubber of the center portion contains a filler. The filler preferably contains at least one selected from silica and carbon black, and more preferably contains both silica and carbon black. The filler reinforces the rubber composition and can improve the fracture properties of the rubber composition. The filler may also contain fillers other than silica and carbon black.

[0046] -silica- The filler preferably contains silica, which contributes to improving the abrasion resistance of the tire.

[0047] Silica has a nitrogen adsorption specific surface area (BET method) of 80m 2 / g or more 330m 2 The nitrogen adsorption specific surface area (BET method) of silica is preferably less than 80 m 2 / g or more 330m 2 When the specific surface area of ​​the silica is less than 100 m / g, a tire containing the rubber composition can be sufficiently reinforced.2 / g or more is more preferable, and 120m 2 / g or more is more preferable, and 140m 2 / g or more is more preferable, and 150m 2 / g or more is more preferable, and 170m 2 / g or more is more preferable, and 180m 2 / g or more is more preferable, and 190m 2 / g or more is more preferable, and 195m 2 From the viewpoint of both abrasion resistance and workability during tire production, the nitrogen adsorption specific surface area of ​​silica (BET method) is preferably 300 m 2 / g or less is more preferable, and 280m 2 / g or less is even more preferable, 2 It is more preferable that the saturation coefficient is 1 / g or less. The nitrogen adsorption specific surface area of ​​silica can be measured by a single point value of the BET method specified by a method in accordance with ISO5794 / 1.

[0048] The silica preferably has a cetyltrimethylammonium bromide adsorption specific surface area (CTAB) of 150 m 2 / g or more, and more preferably 150 to 300m 2 / g, more preferably 150 to 250 m 2 / g, particularly preferably 150 to 220m 2 / g. CTAB is 150m 2 When the CTAB is 300m / g or more, a tire to which the rubber composition is applied can be sufficiently reinforced. 2 When the molecular weight is 1 / g or less, workability is less likely to decrease. The cetyltrimethylammonium bromide adsorption specific surface area (CTAB) can be measured in accordance with ASTM D3765-92.

[0049] Examples of silica include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, and aluminum silicate, and among these, wet silica is preferred. These silicas may be used alone or in combination of two or more.

[0050] From the viewpoint of improving abrasion resistance, the content of silica in the rubber composition is preferably 70 parts by mass or more, more preferably 75 parts by mass or more, and even more preferably 80 parts by mass or more, per 100 parts by mass of the rubber component. Also, from the viewpoint of achieving both abrasion resistance and workability during tire production, the content of silica in the rubber composition is preferably 110 parts by mass or less, more preferably 100 parts by mass or less, per 100 parts by mass of the rubber component.

[0051] -Carbon black- The rubber composition preferably contains carbon black, which reinforces the rubber composition and can improve the fracture properties of the rubber composition, thereby improving the fracture properties of the tire.

[0052] The carbon black is not particularly limited, and examples thereof include GPF, FEF, HAF, ISAF, and SAF grade carbon black. These carbon blacks may be used alone or in combination of two or more.

[0053] From the viewpoints of the fracture properties of the rubber composition and the abrasion resistance of the tire, the content of carbon black in the rubber composition is preferably more than 0 part by mass, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, per 100 parts by mass of the rubber component. Furthermore, from the viewpoint of achieving both abrasion resistance and workability, the content of carbon black in the rubber composition is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of the rubber component.

[0054] The nitrogen adsorption specific surface area (N2SA) of carbon black is not particularly limited and can be selected appropriately depending on the purpose. 2 / g or more. The nitrogen adsorption specific surface area (N2SA) of the carbon black is preferably 70 m 2 / g or more, the abrasion resistance can be improved satisfactorily. The nitrogen adsorption specific surface area (N2SA) of carbon black can be measured in accordance with JIS K 6217-2:2001.

[0055] When the rubber composition of this embodiment contains both silica and carbon black, the ratio of silica to the total content of silica and carbon black is preferably 50% by mass or more and 95% by mass or less, more preferably 70% by mass or more, and more preferably 90% by mass or less.

[0056] -Other fillers- The filler may contain, in addition to carbon black and silica, other fillers such as clay, talc, calcium carbonate, aluminum hydroxide, etc. The amount of these other fillers can be appropriately changed within a range that does not impair the effects of the present invention.

[0057] [Softener] In the tire of the present embodiment, the rubber composition contains a softener. The softener contains a resin, and the resin contains a C5 resin and a C5C9 resin. The softener is a compounding agent that has the effect of softening the rubber composition, and specific examples thereof include resins and liquid plasticizers.

[0058] In the rubber composition, the content of the softener is preferably 40 parts by mass or more per 100 parts by mass of the rubber component. When the content of the softener is 40 parts by mass or more per 100 parts by mass of the rubber component, both wear resistance and workability during tire production can be more highly achieved. From the same viewpoint, the content of the softener is more preferably 45 parts by mass or more per 100 parts by mass of the rubber component. Furthermore, from the viewpoint of suppressing a decrease in wear resistance, the content of the softener is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, per 100 parts by mass of the rubber component. In the present invention, the content of the softener includes not only the content of the softener blended together with the rubber component but also the content of the extender oil blended in advance with the rubber component.

[0059] -resin- In the rubber composition, the resin contains a C5 resin and a C5C9 resin. By containing both a C5 resin and a C5C9 resin, it is possible to achieve both wear resistance and workability of the tire.

[0060] The resin content is preferably 10 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the rubber component. From the viewpoint of achieving both abrasion resistance and workability of the tire, the resin content is preferably 15 parts by mass or more and more preferably 20 parts by mass or less per 100 parts by mass of the rubber component.

[0061] C5 resin refers to a C5 synthetic petroleum resin, and examples of such C5 resins include aliphatic petroleum resins obtained by polymerizing a C5 fraction obtained by thermal cracking of naphtha in the petrochemical industry using a Friedel-Crafts catalyst such as AlCl3 or BF3. The C5 fraction typically includes olefinic hydrocarbons such as 1-pentene, 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene, and diolefinic hydrocarbons such as 2-methyl-1,3-butadiene, 1,2-pentadiene, 1,3-pentadiene, and 3-methyl-1,2-butadiene. As the C5 resin, commercially available products can be used, and examples thereof include the "ESCOLETZ (registered trademark) 1000 series" aliphatic petroleum resins manufactured by ExxonMobil Chemical Corporation, "A100, B170, M100, R100" of the "QUINTONE (registered trademark) 100 series" aliphatic petroleum resins manufactured by Zeon Corporation, and "T-REZ RA100" manufactured by Tonen Chemical Industry Co., Ltd.

[0062] C5C9 resin refers to a C5C9 synthetic petroleum resin. Examples of C5C9 resins include solid polymers obtained by polymerizing petroleum-derived C5 fractions and C9 fractions using a Friedel-Crafts catalyst such as AlCl3 or BF3. More specifically, examples include copolymers primarily composed of styrene, vinyltoluene, α-methylstyrene, indene, etc. As the C5C9 resin, resins with low C9 or higher components are preferred from the viewpoint of compatibility with rubber components. Here, "low C9 or higher components" refers to a resin in which the C9 or higher components are less than 50% by mass, preferably 40% by mass or less, of the total resin. Commercially available C5C9 resins include those sold under the trade name "Quinton (registered trademark) G100B" (manufactured by Zeon Corporation), the trade name "ECR213" (manufactured by ExxonMobil Chemical Corporation), and the trade name "T-REZ RD104" (manufactured by Tonen Chemical Industry Co., Ltd.).

[0063] In the rubber composition, the ratio of the C5 resin content to the C5C9 resin content is preferably 0.1 or more and 1.0 or less. When the ratio of the C5 resin content to the C5C9 resin content is 0.1 or more and 1.0 or less, excellent workability is achieved. From the viewpoint of workability, the ratio of the C5 resin content to the C5C9 resin content is more preferably 0.3 or more, even more preferably 0.5 or more, more preferably 0.7 or less, and even more preferably 0.6 or less.

[0064] The resin may contain other resins in addition to the C5 resin and the C5C9 resin, such as a C9 resin, a dicyclopentadiene resin, a terpene phenol resin, a terpene resin, a rosin resin, and an alkylphenol resin.

[0065] C9 resins are resins obtained by polymerizing aromatic compounds with a carbon number of 9, primarily consisting of vinyltoluene, alkylstyrene, and indene, which are by-products of petrochemical base materials such as ethylene and propylene produced during the thermal decomposition of naphtha in the petrochemical industry. Specific examples of C9 fractions obtained by thermal decomposition of naphtha include vinyltoluene, α-methylstyrene, β-methylstyrene, γ-methylstyrene, o-methylstyrene, p-methylstyrene, and indene. The C9 resins can also be obtained by copolymerizing the C8-C10 fractions as a mixture with, for example, a Friedel-Crafts catalyst, using as raw materials the C9 fraction, C8 fractions such as styrene, C10 fractions such as methylindene and 1,3-dimethylstyrene, and even naphthalene, vinylnaphthalene, vinylanthracene, and p-tert-butylstyrene. The C9 resins may also be modified petroleum resins modified with compounds containing hydroxyl groups, unsaturated carboxylic acid compounds, and the like. Commercially available C9 resins can be used. For example, unmodified C9 petroleum resins include those under the trade names "Nippon Oil Neopolymer (registered trademark) L-90," "Nippon Oil Neopolymer (registered trademark) 120," "Nippon Oil Neopolymer (registered trademark) 130," and "Nippon Oil Neopolymer (registered trademark) 140" (manufactured by JX Nippon Oil & Energy Corporation).

[0066] Dicyclopentadiene resin is a petroleum resin produced primarily from dicyclopentadiene obtained by dimerizing cyclopentadiene. Commercially available dicyclopentadiene resins can be used, such as alicyclic petroleum resins manufactured by Zeon Corporation under the trade name Quinton (registered trademark) 1000 Series (product numbers 1105, 1325, and 1340).

[0067] Terpene phenolic resins can be obtained, for example, by reacting terpenes with various phenols using a Friedel-Crafts catalyst or by further condensing them with formalin. The terpenes used as raw materials are not particularly limited, but monoterpene hydrocarbons such as α-pinene and limonene are preferred, with α-pinene being more preferred, and α-pinene being particularly preferred. Commercially available terpene phenolic resins include those sold under the trade names "Tamanol 803L" and "Tamanol 901" (manufactured by Arakawa Chemical Industries, Ltd.), and the "YS Polystar® U" series, "YS Polystar® T" series, "YS Polystar® S" series, "YS Polystar® G" series, "YS Polystar® N" series, "YS Polystar® K" series, and "YS Polystar® TH" series (manufactured by Yasuhara Chemical Co., Ltd.).

[0068] Terpene resins are solid resins obtained by blending turpentine oil, which is obtained simultaneously when rosin is obtained from pine trees, or a polymerization component separated from this, and polymerizing the blend using a Friedel-Crafts catalyst, and examples of such resins include β-pinene resin and α-pinene resin. Commercially available terpene resins can be used, such as those sold under the trade name "YS Resin" series (PX-1250, TR-105, etc.) by Yasuhara Chemical Co., Ltd. and those sold under the trade name "Picolite" series (A115, S115, etc.) by Hercules.

[0069] Rosin resin is the residue remaining after collecting balsams such as pine resin (pine tar), which is the sap of plants in the Pinaceae family, and distilling turpentine essential oil. It includes natural resins whose main component is rosin acid (abietic acid, palustric acid, isopimaric acid, etc.), as well as modified and hydrogenated resins obtained by modifying, hydrogenating, or otherwise processing these. Examples include natural resin rosin, its polymerized rosin, and partially hydrogenated rosin; glycerin ester rosin, its partially hydrogenated rosin, fully hydrogenated rosin, and polymerized rosin; pentaerythritol ester rosin, its partially hydrogenated rosin, and polymerized rosin. Natural resin rosins include gum rosin, tall oil rosin, and wood rosin, which are contained in raw pine resin and tall oil. The rosin resin may be a commercially available product, such as "Neotol 105" (manufactured by Harima Chemical Co., Ltd.), "SN Tack 754" (manufactured by San Nopco Ltd.), "Lime Resin No. 1," "Pensel A," and "Pensel AD" (manufactured by Arakawa Chemical Industries, Ltd.), "Polypale" and "Pentalin C" (manufactured by Eastman Chemical Co., Ltd.), or "Hi-Rosin (registered trademark) S" (manufactured by Taisho Matsu Oil Co., Ltd.).

[0070] The alkylphenol resin can be obtained, for example, by condensation reaction of alkylphenol and formaldehyde in the presence of a catalyst. Commercially available alkylphenol resins include those sold under the trade name "Hitanol 1502P" (an alkylphenol formaldehyde resin, manufactured by Hitachi Chemical Co., Ltd.), "Tackirol 201" (an alkylphenol formaldehyde resin, manufactured by Taoka Chemical Co., Ltd.), "Tackirol 250-I" (a brominated alkylphenol formaldehyde resin, manufactured by Taoka Chemical Co., Ltd.), "Tackirol 250-III" (a brominated alkylphenol formaldehyde resin, manufactured by Taoka Chemical Co., Ltd.), and those sold under the trade names "R7521P," "SP1068," "R7510PJ," "R7572P," and "R7578P" (manufactured by SI Group Inc.).

[0071] The resin contained in the rubber composition may be hydrogenated.

[0072] -Liquid plasticizer- The softener preferably further contains a liquid plasticizer. When the rubber composition contains a liquid plasticizer, workability during tire production can be improved. Here, the liquid plasticizer is liquid at 25°C (room temperature).

[0073] Examples of liquid plasticizers include oils. Examples of such oils include, but are not limited to, petroleum-based softeners such as aromatic oils, paraffinic oils, and naphthenic oils; and plant-based softeners such as palm oil, castor oil, cottonseed oil, and soybean oil. Among these, petroleum-based softeners such as aromatic oils, paraffinic oils, and naphthenic oils are preferred.

[0074] The content of the liquid plasticizer is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and even more preferably 8 parts by mass or more per 100 parts by mass of the rubber component from the viewpoint of improving workability during tire production. Also, the content of the liquid plasticizer is preferably 10 parts by mass or less per 100 parts by mass of the rubber component from the viewpoint of suppressing a decrease in abrasion resistance.

[0075] [Other ingredients] In addition to the rubber components, fillers, and softeners described above, the rubber composition may contain compounding agents commonly used in the rubber industry, such as silane coupling agents, stearic acid, antioxidants, zinc oxide (zinc white), vulcanization accelerators, vulcanizing agents, etc., selected appropriately within the scope that does not impair the object of the present invention.

[0076] Examples of the silane coupling agent include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N ,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazolyl tetrasulfide, 3-triethoxysilylpropyl benzothiazolyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis(3-diethoxymethylsilylpropyl)tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, dimethoxymethylsilylpropyl benzothiazolyl tetrasulfide, etc. The content of the silane coupling agent is preferably in the range of 2 to 20 parts by mass, more preferably in the range of 5 to 15 parts by mass, per 100 parts by mass of silica.

[0077] Examples of the antioxidant include N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6C), 2,2,4-trimethyl-1,2-dihydroquinoline polymer (TMDQ), 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (AW), N,N'-diphenyl-p-phenylenediamine (DPPD), etc. The content of the antioxidant is not particularly limited, and is preferably in the range of 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass, per 100 parts by mass of the rubber component.

[0078] Examples of the vulcanization accelerator include sulfenamide-based vulcanization accelerators, guanidine-based vulcanization accelerators, thiazole-based vulcanization accelerators, thiuram-based vulcanization accelerators, and dithiocarbamate-based vulcanization accelerators. Examples of the vulcanizing agent include sulfur. The total content of the vulcanization system (vulcanization package) containing the vulcanization accelerator, vulcanizing agent, and stearic acid is not particularly limited, but is preferably in the range of 1 to 25 parts by mass, and more preferably 5 to 20 parts by mass, per 100 parts by mass of the rubber component.

[0079] (Other components) So far, the rubber composition in the tread rubber of the center portion has been described, but the component compositions of other rubber compositions such as the rubber composition in the shoulder portion constituting the tread rubber (shoulder rubber) in the shoulder portion and the rubber compositions constituting other tire parts are not particularly limited.

[0080] The other rubber composition may contain the rubber component, filler, softener, and silane coupling agent that may be contained in the rubber composition of the tread rubber in the center portion, and may also contain stearic acid, an antioxidant, zinc oxide (zinc white), a vulcanization accelerator, a vulcanizing agent, etc.

[0081] From the viewpoint of grip, it is preferable that the total amount of softener in the rubber composition of the tread rubber of the shoulder portion is greater than the total amount of softener in the rubber composition of the tread rubber of the center portion.

[0082] (Tire manufacturing method) The tire of the present embodiment is obtained by molding and vulcanizing the rubber composition. The method for producing the rubber composition is not particularly limited, but it can be produced, for example, by blending the above-mentioned rubber component, filler, and softener with various components appropriately selected as necessary, and kneading, heating, extruding, etc. The obtained rubber composition can be vulcanized to produce a vulcanized rubber.

[0083] The kneading conditions are not particularly limited, and various conditions such as the input volume of the kneading device, the rotation speed of the rotor, the ram pressure, the kneading temperature, the kneading time, the type of kneading device, etc. can be appropriately selected depending on the purpose. Examples of the kneading device include a Banbury mixer, an intermix, a kneader, a roll, etc. that are usually used for kneading rubber compositions.

[0084] The conditions for the heat-in are not particularly limited, and various conditions such as the heat-in temperature, heat-in time, and heat-in device can be appropriately selected depending on the purpose. Examples of the heat-in device include a heat-in roll mill typically used for heat-in of rubber compositions.

[0085] The extrusion conditions are not particularly limited, and various conditions such as extrusion time, extrusion speed, extrusion device, and extrusion temperature can be appropriately selected depending on the purpose. Examples of the extrusion device include an extruder typically used for extruding rubber compositions. The extrusion temperature can be appropriately determined.

[0086] The vulcanization equipment, method, conditions, etc. are not particularly limited and can be appropriately selected depending on the purpose. Examples of vulcanization equipment include a molding vulcanizer using a mold used for vulcanizing rubber compositions. The vulcanization temperature is, for example, about 100 to 190°C.

[0087] The tire of this embodiment may be obtained by molding an unvulcanized rubber composition and then vulcanizing it, depending on the type of tire to be applied, or by molding a semi-vulcanized rubber that has been subjected to a pre-vulcanization step and then further vulcanizing it. The tire of this embodiment is preferably a pneumatic tire, and the gas to be filled into the pneumatic tire may be normal air or air with an adjusted oxygen partial pressure, or an inert gas such as nitrogen, argon, or helium.

[0088] (Application) The tire of this embodiment can be used for various purposes, not limited to two-wheeled vehicles and four-wheeled vehicles, but the effects of the present invention can be easily achieved by using it for two-wheeled vehicles in particular. When used as a motorcycle tire, it may be a front tire or a rear tire, but in the present invention, since it is possible to achieve high levels of both wear resistance and workability during tire production, the effects of the present invention are particularly likely to be achieved when applied to a rear tire. The type of motorcycle is not particularly limited and can be appropriately selected depending on the purpose. Examples of types of motorcycle include racing motorcycles, motorcycles for general public roads, motorcycles for on-road use, and motorcycles for off-road use. Among these, motorcycles for general public roads and motorcycles for on-road use are preferred as motorcycles in which the effects of the present invention are particularly likely to be realized, and motorcycles for general public roads are more preferred. [Example]

[0089] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0090] <Preparation of Rubber Composition for Tread Rubber of Shoulder Portion> According to the compounding recipe shown in Table 1, a rubber composition for the tread rubber of the shoulder portion (rubber composition for shoulder rubber) was prepared using a conventional Banbury mixer. In Table 1, the "total amount of softener" means the total amount of the softener as a compounding component and the oil-extended amount of the rubber component.

[0091] [Measurement of rubber composition in tread rubber in shoulder area] -Storage modulus- The storage modulus of the rubber composition in the tread rubber of the shoulder portion was measured using a viscoelasticity measuring device (manufactured by Ueshima Seisakusho Co., Ltd.) at a temperature of 60° C., a frequency of 52 Hz, and a strain of 1.0%. The measurement results are shown in Table 1.

[0092] [Table 1]

[0093] *1 SBR: Styrene-butadiene rubber, manufactured by ENEOS Materials Corporation, emulsion-polymerized styrene-butadiene rubber, product name "HP755B", contains 37.5 parts by mass of extender oil per 100 parts by mass of rubber component. The middle row indicates the rubber component content and the bottom row indicates the extender oil content. *2 BR: Butadiene rubber, manufactured by ENEOS Materials Corporation, product name "BR01" *3 Carbon black, manufactured by Asahi Carbon Co., Ltd., product name "ASAHI#107" *4 Silica: Tosoh Silica Corporation, product name "Nipsil AQ" *5 Oil: JX Nippon Oil & Energy Corporation, product name "A / O MIX" *6 C5C9 resin: ENEOS Corporation, product name "T-REZ RD104" *7 Coupling agent: Shin-Etsu Chemical Co., Ltd., product name "ABC-856" *8 Other chemicals: Total amount including wax, anti-aging agents, and workability improvers *9 Vulcanization package: total amount including vulcanization accelerator, sulfur, and stearic acid

[0094] <Preparation of Rubber Composition for Tread Rubber of Center Portion> Using a conventional Banbury mixer, rubber compositions for the tread rubber of the center portion (rubber compositions for center rubber) of Example 1 and Comparative Examples 1 to 3 were prepared according to the compounding recipes shown in Table 2. Table 2 shows the compounding recipes and evaluation results. In Table 2, the "total amount of softener" means the total amount of the softener as a compounding component and the oil-extended amount of the rubber component.

[0095] [Measurement of rubber composition of tread rubber in the center part] -Storage modulus- The storage modulus of the rubber composition in the tread rubber of the center portion was measured using a viscoelasticity measuring device (manufactured by Ueshima Seisakusho Co., Ltd.) at a temperature of 60°C, a frequency of 52 Hz, and a strain of 1.0%. In addition, from the measurement results of the storage modulus of the rubber composition in the tread rubber of the shoulder portion and the rubber composition in the tread rubber of the center portion, the ratio of the storage modulus of the tread rubber of the center portion at 60°C to the storage modulus of the tread rubber of the shoulder portion at 60°C (storage modulus (center portion) / storage modulus (shoulder portion)) was calculated. The measurement results and calculation results are shown in Table 2.

[0096] <Tire manufacturing> Using each of the prepared rubber compositions, motorcycle tires (size: 180 / 55ZR17) were manufactured in a conventional manner, each having a pair of bead portions, a pair of sidewall portions, and a tread portion connected to both sidewall portions, with the tread portion being divided into three portions in the tire width direction by a center portion including the tire equatorial plane and a pair of shoulder portions including the tread ends.

[0097] <Evaluation> The workability during tire production and the abrasion resistance were evaluated by the following methods.

[0098] (1) Workability The adhesive strength between the unvulcanized rubber composition and metal at 90° C. was measured using a tack meter, and the reciprocal of the adhesive strength of Comparative Example 1 was set to 100 and expressed as an index. The larger the index, the smaller the adhesive force and the better the workability.

[0099] (2) Abrasion resistance A test rider drove the vehicle 3,500 km at 80 km / h on a paved test course. After the run, the remaining tread depth was measured and the tire wear resistance was evaluated based on the remaining tread depth. The evaluation result of Comparative Example 1 was expressed as an index, with 100 as the index. The larger the index, the more excellent the abrasion resistance.

[0100] [Table 2]

[0101] *10 C5 resin: Manufactured by ENEOS, product name "T-REZ RA100"

[0102] From Table 2, it can be seen that the tire of this embodiment is able to achieve both workability and wear resistance. [Industrial Applicability]

[0103] According to the present invention, it is possible to provide a tire that can achieve both wear resistance and workability during tire production.

[0104] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] The SDGs have been proposed to realize a sustainable society. One embodiment of the present invention is thought to be a technology that can contribute to "No. 12 Responsible Consumption and Production" and "No. 13 Take concrete action against climate change." [Explanation of symbols]

[0105] 1: Tires 2: Tread section 3: Bead section 4: Sidewall 5: Bead core 6: Carcass layer 7: Center tread rubber 8: Tread rubber on shoulder 9: Center section 10: Shoulder section 11: Equatorial plane 12: Tread edge

Claims

1. A tire comprising a pair of bead portions, a pair of sidewall portions, and a tread portion connected to both sidewall portions, the tread portion being divided into at least three portions in the tire width direction by a center portion including the tire equatorial plane and a pair of shoulder portions including tread edges, the tread rubber of the center portion is made of a rubber composition containing at least a rubber component, a filler, and a softener, the rubber component contains at least one selected from styrene-butadiene rubber and butadiene rubber, The tire, wherein the softener contains a resin, and the resin contains a C5-based resin and a C5C9-based resin.

2. The tire according to claim 1, wherein the filler contains 70 parts by mass or more of silica per 100 parts by mass of the rubber component.

3. The tire of claim 1 wherein the filler comprises carbon black.

4. The tire according to claim 1, wherein an amount of the resin is equal to or greater than 10 parts by mass and equal to or less than 25 parts by mass per 100 parts by mass of the rubber component.

5. The tire of claim 1 , wherein the softener further comprises a liquid plasticizer.

6. The tire according to claim 1, wherein the content of the softener is 40 parts by mass or more per 100 parts by mass of the rubber component.

7. The tire of claim 1, wherein the rubber component comprises styrene-butadiene rubber and butadiene rubber.

8. The tire according to claim 1, wherein a ratio of a storage modulus at 60°C of the tread rubber of the center portion to a storage modulus at 60°C of the tread rubber of the shoulder portions exceeds 1.

72.

9. The tire according to claim 1, which is for a motorcycle.

Images