Tire

Abstract

To improve total performance of low fuel consumption and high-speed durability.SOLUTION: A tire comprises: a carcass comprising a carcass cord; a belt which comprises a belt cord and is provided outside the carcass in a tire radial direction; a band which comprises a band cord and is provided outside the belt in the tire radial direction; and a tread provided outside the band in the tire radial direction. The band cord comprises a polyethylene terephthalate fiber. The carcass is formed by using a carcass cord having a total fineness of more than 2400 dtex. The tread is formed, by using a rubber composition comprising more than 20 pts.mass of isoprene rubber in 100 pts.mass of a rubber component, so as to have rubber hardness (Shore hardness) Hs of more than 70 pt. A sum of a band cord diameter Bar (mm), a belt cord diameter Ber (mm), a carcass cord diameter Car (mm), and a tread thickness Trg (mm), i.e., (Bar+Ber+Car+Trg), is less than 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tire.

Background Art

[0002] In a passenger car tire, as in Patent Document 1, generally, a band (also called a cap ply) is provided between the tread and the belt from the viewpoint of preventing deformation of the tire due to centrifugal force during high-speed driving.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to improve the overall performance of low fuel consumption and high-speed durability.

Means for Solving the Problems

[0005] The present invention is a carcass including carcass cords, a belt including belt cords and provided on the outer side in the tire radial direction of the carcass, a band including band cords and provided on the outer side in the tire radial direction of the belt, and a tire including a tread provided on the outer side in the tire radial direction of the band, wherein the band cords contain polyethylene terephthalate fibers, the carcass is formed using carcass cords having a total fineness of more than 2400 dtex, the tread is formed to have a rubber hardness (Shore hardness) Hs of more than 70 pt using a rubber composition containing more than 20 parts by mass of isoprene rubber in 100 parts by mass of the rubber component. Furthermore, the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the band cord, the diameter Ber (mm) of the belt cord, the diameter Car (mm) of the carcass cord, and the thickness Trg (mm) of the tread is less than 20, and the tire is characterized by this.

Effect of the Invention

[0006] According to the present invention, it is possible to improve the overall performance of low fuel consumption and high-speed durability.

Brief Description of the Drawings

[0007]

Figure 1

Mode for Carrying Out the Invention

[0008] [1] Features of the tire according to the present invention First, the features of the tire according to the present invention will be described.

[0009] 1. Outline The tire according to the present invention includes a carcass having a carcass cord, a belt having a belt cord and provided on the outer side in the tire radial direction of the carcass, a band having a band cord and provided on the outer side in the tire radial direction of the belt, and a tread provided on the outer side in the tire radial direction of the band. The band cord contains polyethylene terephthalate fiber (PET fiber). The carcass is formed using a carcass cord having a total fineness of more than 2400 dtex. The tread is formed with a rubber hardness (Shore hardness) Hs of more than 70 pt using a rubber composition containing more than 20 parts by mass of isoprene rubber in 100 parts by mass of the rubber component. Furthermore, the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the band cord, the diameter Ber (mm) of the belt cord, the diameter Car (mm) of the carcass cord, and the thickness Trg (mm) of the tread is less than 20.

[0010] By having these features, it is considered that, as described later, it is possible to improve the overall performance of low fuel consumption and high-speed durability.

[0011] In this specification, the "cord diameter" in the belt cord diameter, belt cord diameter, and carcass cord diameter means the diameter when the circumscribed circle of the cross section perpendicular to the cord extending direction is a perfect circle, and in the case of an ellipse or the like, it refers to the equivalent circle diameter (the diameter of the circle assumed when the cross-sectional area is the same).

[0012] 2. Mechanism of effect manifestation in the tire according to the present invention Regarding the mechanism of the above-described effect manifestation in the tire according to the present invention, it is considered as follows.

[0013] (1) Band The band may be one layer or two layers. Also, the band may be formed over the entire width direction of the tread, or may be formed only at both ends of the tread. However, it is preferable to use in combination a band formed over the entire width direction of the tread and a band formed at both ends in the width direction of the tread.

[0014] In the tire according to the present invention, a cord containing PET fiber (PET cord) is used for the band cord.

[0015] The band cord can be composed of fibers. As the fibers constituting the band cord, polyester fibers such as PET (polyethylene terephthalate) fibers and PEN (polyethylene naphthalate) fibers can be used. The fibers constituting the carcass cord are preferably sustainable PET such as those recycled from used products or waste products (recycled PET) and those synthesized from biomass (biomass PET). Also, the band cord may be a hybrid cord using a combination of PET fibers and other fibers (such as aramid fibers).

[0016] Since the PET cord is more rigid than the nylon 66 cord as described above, by adopting the PET cord as the band cord, the cord gauge (the diameter of the band cord) can be made smaller and the prep gauge (the thickness of the band) can be made smaller than when using the nylon 66 cord. As a result, the prep weight (the weight of the band) can be reduced, the tire weight can be reduced, and the LRR can be achieved.

[0017] (2) Carcass However, as described above, since the PET cord is inferior in compression fatigue resistance to the nylon 66 cord, there is a risk of degrading the high-speed durability of the tire.

[0018] Therefore, in the tire according to the present invention, first, as the carcass, a carcass formed using a carcass cord having a total fineness of more than 1200 dtex is used.

[0019] By forming the carcass using a carcass cord having a total fineness of more than 1200 dtex and a certain thickness or more, the lateral spring constant can be increased, and the degree of deflection generated in the side portion during driving can be changed (decreased), and the strength of the tire can be ensured. Therefore, it is considered that the handling stability can be improved and the high-speed durability can be improved. The total fineness of the carcass cord is preferably 1500 dtex or more, and more preferably 2000 dtex or more. As the upper limit, for example, it is preferably 5000 dtex or less, and more preferably 4500 dtex or less.

[0020] The total fineness of the carcass cord described above can be measured in accordance with the method specified in JIS L1017:2002.

[0021] The carcass cord is twisted from one or more yarns, and preferably twisted from two yarns. In the case of two-ply twisting, the fineness of each yarn is preferably 1200 dtex or more and preferably 2500 dtex or less.

[0022] The carcass cords can be made of fibers. As the fibers constituting the carcass cords, conventionally known ones such as polyester fibers such as PET (polyethylene terephthalate) fibers and PEN (polyethylene naphthalate) fibers, polyamide fibers such as nylon 6 fibers and nylon 66 fibers, aramid fibers, etc. can be used. The fibers constituting the carcass cords may be recycled from used products or waste products (recycled materials), or may be synthesized from biomass (biomass materials).

[0023] And the carcass may be one layer or two layers, but preferably one layer. By using a one-layer carcass structure, it is considered that the weight reduction and LRR (Low Rolling Resistance) of the tire can be achieved more effectively compared to the case of using a two-layer carcass structure.

[0024] Also, by using such a carcass part, the bending rigidity in the axial direction is sufficiently reduced, and when a camber angle is formed during cornering, the side part can be sufficiently deflected to bring more of the tread surface into contact with the ground, so it is considered that the handling stability can be improved.

[0025] (3) Tread Next, in the tire according to the present invention, by forming a tread with a rubber hardness (shore hardness) Hs exceeding 70 pt using a rubber composition containing more than 20 parts by mass of isoprene rubber in 100 parts by mass of the rubber component, the LRR improvement due to tire weight reduction and the high-speed durability are achieved. The tread may be one layer, two layers, or three or more layers. When the tread is two or more layers, it is preferable to form the tread with a rubber hardness (shore hardness) Hs exceeding 70 pt using a rubber composition containing more than 20 parts by mass of isoprene rubber in 100 parts by mass of the rubber component for the layer on the ground contact side (cap layer).

[0026] By containing more than 20 parts by mass of isoprene rubber in 100 parts by mass of the rubber component, a low heat-generating tread capable of reducing heat generation during high-speed driving can be obtained, so it is considered that LRR can be achieved. In addition, since it is possible to suppress a decrease in the rigidity (modulus) of the PET cord that occurs as the temperature of the tread rises, it is considered that high-speed durability can be improved. The blending amount of the isoprene rubber is preferably 30 parts by mass or more, more preferably 40 parts by mass or more, in 100 parts by mass of the rubber component. As the upper limit, for example, it is preferably 70 parts by mass or less, more preferably 60 parts by mass or less.

[0027] At this time, if the rubber hardness (Shore hardness) Hs of the tread is small and soft, during high-speed driving, the deformation amount of the tread increases, the compression applied to the band increases, and there is a risk that the high-speed durability deteriorates due to compression fatigue. Therefore, in the present invention, the rubber hardness (Shore hardness) Hs of the tread is set to more than 70 pt.

[0028] Thereby, sufficient rigidity can be ensured and the deformation of the tread during high-speed driving can be suppressed. Therefore, it is considered that the compression fatigue applied to the band can be reduced and the high-speed durability can be improved. Furthermore, by ensuring the rigidity of the tread, the deformation of the tread during turning can be suppressed and the generated force can be easily transmitted, so that the handling stability can be ensured. The rubber hardness (Shore hardness) Hs of the tread is preferably more than 71 pt, more preferably more than 73 pt, and even more preferably more than 75 pt. As the upper limit, for example, it is preferably 85 pt or less, more preferably 80 pt or less.

[0029] The above-mentioned rubber hardness (Shore hardness) Hs can be measured using a Type A durometer in accordance with the method specified in JIS K6253-3:2012.

[0030] (4)Bar+Ber+Car+Trg In the present invention, the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the band cord, the diameter Ber (mm) of the belt cord, the diameter Car (mm) of the carcass cord, and the thickness Trg (mm) of the tread is controlled to be less than 20. Thereby, the respective effects due to the use of the above-described PET cord, the carcass structure, and the characteristics of the tread rubber composition cooperate to improve the overall performance of low fuel consumption and high-speed durability. It is preferably 18 or less, and more preferably 15 or less. As the lower limit, for example, it is preferably 8 or more.

[0031] [2] Preferred embodiments By adopting the following embodiments, a greater effect can be obtained.

[0032] 1. Band cord In the present invention, as described above, a PET cord is used as the band cord, but a PET cord containing sustainable PET fibers is preferably used. Sustainable PET fibers are fibers containing sustainable materials such as recycled PET and biomass PET. In this specification, among specific materials (for example, PET), materials obtained by recycling used products or waste materials, or materials obtained using biomass as a raw material are referred to as sustainable materials (for example, sustainable PET).

[0033] In addition, the diameter (cord diameter) of the band cord is preferably small for reducing the weight of the tire, but is preferably 0.2 mm or more and 0.9 mm or less, and more preferably 0.3 mm or more and 0.7 mm or less. Further, the total fineness of the band cord is preferably 1000 dtex or more, more preferably 1500 dtex or more, and even more preferably 2000 dtex or more. Also, the total fineness of the band cord is preferably 5000 dtex or less, more preferably 4500 dtex or less, and even more preferably 4000 dtex or less.

[0034] 2. Belt The belt may be single-layered, double-layered, or triple-layered or more.

[0035] As the belt cord constituting the belt, a steel cord is preferable. From the viewpoint of reducing the weight of the tire, it is preferably a cord composed of a plurality of filaments, and may be a stranded wire in which a plurality of filaments are twisted. The number of filaments constituting the cord is preferably 1 or more and 8 or less, and more preferably 1 or more and 4 or less. As the lower limit, for example, it is preferably 2 or more. In the case of a belt cord having 1 or more and 4 or less filaments, the twisting method may be single-twist (for example, 1×2 structure, etc.) or layer-twist (for example, 2+2 structure, etc.), or it may be untwisted (non-twisted). The material of the filaments constituting the belt cord is preferably a metal, and more preferably iron. The cross-section of the filaments constituting the belt cord may be circular or elliptical, but a circle is preferable, and it may be corrugated or may be treated by plating. Also, the diameter of the belt cord (cord diameter) is preferably small for reducing the weight of the tire, but is preferably 0.2 mm or more and 0.9 mm or less, and more preferably 0.3 mm or more and 0.7 mm or less.

[0036] 3. Tire weight and maximum load capacity The ratio of the tire weight (kg) to the maximum load capacity (kg) of the tire (tire weight / maximum load capacity) is preferably less than 0.02, more preferably less than 0.015, still more preferably less than 0.012, and particularly preferably less than 0.009. As the lower limit, for example, it is preferably 0.008 or more.

[0037] The tire weight can be reduced, for example, by reducing the fineness of various cords (band cord, belt cord, carcass cord) constituting the tire member, reducing the thickness of the tread and sidewall, or reducing the density of the rubber composition used for them.

[0038] Thus, a tire with a tire weight smaller than the maximum load capacity of the tire has a relatively thin rubber thickness, so it can sufficiently suppress the temperature rise of the entire tire and reduce the deformation amount, and can further improve the durability of the tire during driving. It is considered that the merits of LRR improvement due to weight reduction and high-speed durability can be achieved simultaneously. Here, in the above, "tire weight (kg)" refers to the weight of the tire alone excluding the weight of the rim.

[0039] And, "maximum load capacity (kg)" can be obtained as WL from the following formula when the tire cross-sectional width measured in the normal state is Wt (mm), the tire cross-sectional height is Ht (mm), and the tire outer diameter is Dt (mm). In the following formula, V is the virtual volume of the tire (mm 3 ). Here, the tire cross-sectional width Wt is the maximum width between the outer surfaces of the sidewalls excluding patterns or letters etc. on the tire side surface in the normal state. And the tire cross-sectional height Ht is half of the difference between the outer diameter of the tire and the nominal rim diameter. V ={(Dt / 2) 2 -(Dt / 2 - Ht) 2}×π×Wt WL = 0.000011×V + 175

[0040] In the above description, the "normal state" means that the tire is mounted on the normal rim and filled with the normal internal pressure, and moreover, it is in a no-load state. Note that the "normal internal pressure" refers to the air pressure defined for each tire in the standard system including the standard on which the tire is based. For JATMA (Japan Automobile Tire Association), it is the "maximum air pressure"; for ETRTO (The European Tyre and Rim Technical Organisation), it is "INFLATION PRESSURE"; for TRA (The Tire and Rim Association, Inc.), it refers to the maximum value described in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". Similar to the normal rim, refer to JATMA, ETRTO, and TRA in that order, and follow the relevant standard if there is an applicable size during the reference. In the case of a tire not defined in the standard, it refers to the normal internal pressure (however, 250 kPa or more) of another tire size (defined in the standard) described with the normal rim as the standard rim. Note that when there are multiple normal internal pressures of 250 kPa or more described, it refers to the minimum value among them.

[0041] Note that the "normal rim" is the rim defined for each tire in the standard system including the standard on which the tire is based. For example, for JATMA, it is the standard rim for the applicable size described in the "JATMA YEAR BOOK"; for ETRTO, it is the "Measuring Rim" described in the "STANDARDS MANUAL"; for TRA, it refers to the "Design Rim" described in the "YEAR BOOK". Refer to JATMA, ETRTO, and TRA in that order, and follow the relevant standard if there is an applicable size during the reference. In the case of a tire not defined in the standard, it refers to the rim that can be mounted on the tire and can hold the internal pressure, that is, among the rims that do not cause air leakage between the rim / tire, the one with the smallest rim diameter and then the narrowest rim width.

[0042] 4. Material of carcass cord The material of the carcass cord is not particularly limited, but it is preferably a cord containing PET fibers (PET cord), and more preferably contains sustainable PET fibers. Sustainable PET fibers include sustainable materials such as recycled PET and biomass PET. Since PET cord has higher rigidity compared to nylon 66 cord, adopting PET cord as the carcass cord can improve high-speed durability. Also, when comparing PET cord with nylon 66 cord having the same binding force, the cord diameter becomes smaller. Therefore, by using PET cord, the tire weight can be reduced, and the LRR can be achieved by weight reduction.

[0043] 5. Diameter of Carcass Cord Car The diameter of the carcass cord (cord diameter) is preferably small for tire weight reduction, but is preferably 0.2 mm or more and 0.9 mm or less, and more preferably 0.4 mm or more and 0.8 mm or less.

[0044] 6. Thickness of Tread Trg The thickness of the tread is preferably 4 mm or more, and more preferably 6 mm or more. This can reduce the compression received by the band, so the compression fatigue resistance can be improved and the high-speed durability can be improved. If the tread is made too thick, the tire weight will increase, and the LRR effect due to the weight reduction of tire members other than the tread will be canceled out. Also, if the rigidity of the tire decreases, the handling stability may deteriorate. Therefore, as the upper limit, it is preferably 20 mm or less, more preferably 15 mm or less, and even more preferably 10 mm or less.

[0045] The thickness of the tread refers to the thickness of the tread on the tire equator plane in the radial cross-section of the tire. When the tread is formed of a single rubber composition, it is the thickness of the rubber composition. When it is formed of a laminated structure of a plurality of rubber compositions, it refers to the total thickness of these layers. It can be measured by making the bead portion conform to the normal rim width in the cross-section obtained by cutting the tire in the radial direction.

[0046] [3] Embodiment Hereinafter, based on the embodiment, the present invention will be specifically described.

[0047] 1. Tire according to this embodiment FIG. 1 is a schematic cross-sectional view for explaining the structure of the tire according to this embodiment. In FIG. 1, the vertical direction is the radial direction of the tire, the horizontal direction is the rotational axis direction of the tire, and the direction perpendicular to the paper surface is the circumferential direction of the tire. In FIG. 1, the dashed-dotted line CL represents the equatorial plane of the tire. Since the shape of this tire is symmetric with respect to the equatorial plane except for the tread pattern, 1 / 4 of the whole tire is shown in FIG. 1.

[0048] As shown in FIG. 1, the tire 1 includes a tread 2, a pair of sidewalls 3, a pair of chafer 4, a pair of beads 5, an inner liner 6, a carcass 7, a belt 8, a pair of fillers 9, and a band 10. The carcass 7, the belt 8, the band 10, and the tread 2 are arranged from the inner side to the outer side in the tire radial direction.

[0049] With such a configuration, as described above, a cord obtained by twisting one yarn containing PET fiber as a band cord is used to appropriately form the tread and the carcass. Further, by appropriately controlling the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the band cord, the diameter Ber (mm) of the belt cord, the diameter Car (mm) of the carcass cord, and the thickness Trg (mm) of the tread, it is possible to improve the overall performance of low fuel consumption and high-speed durability.

[0050] 2. Rubber composition for tread In this embodiment, the rubber composition for tread can be obtained by kneading various compounding materials such as a rubber component, a filler (reinforcing material), a softening agent component (oil, resin component, etc.), and an antioxidant.

[0051] (1) Compounding materials (a) Rubber component As the rubber component, isoprene rubbers such as natural rubber (NR) may be used alone, or isoprene rubbers and diene rubbers other than isoprene rubbers may be used in combination. Examples of diene rubbers other than isoprene rubbers include diene rubbers such as styrene butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR). Two types (NR and SBR or NR and BR) may be used in combination, or three types (NR, SBR, and BR) may be used in combination.

[0052] (i) Isoprene rubber As isoprene rubbers, natural rubber (NR) and synthetic polyisoprene rubbers such as synthetic polyisoprene (isoprene rubber (IR), modified isoprene rubber (modified IR)) and other isoprene rubbers other than NR (modified natural rubber (modified NR), denatured natural rubber (denatured NR)) can be used.

[0053] As NR, for example, those commonly used in the tire industry such as SVR-L, SIR20, RSS#3, TSR20, etc. can be used. NR is excellent in strength compared to other rubbers.

[0054] The content of NR in 100 parts by mass of the rubber component is more than 20 parts by mass, preferably 30 parts by mass or more, and more preferably 40 parts by mass or more. The upper limit is preferably 70 parts by mass or less, and more preferably 60 parts by mass or less.

[0055] Examples of isoprene rubbers other than NR include isoprene rubber (IR), modified NR, denatured NR, denatured IR, etc. IR is not particularly limited, and for example, general ones such as IR2200 manufactured by Nippon Zeon Co., Ltd. can be used in the tire industry. Examples of modified NR include deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc. Examples of denatured NR include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. Examples of denatured IR include epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, etc. These may be used alone or in combination of two or more.

[0056] The upper limit of the content of isoprene rubber in 100 parts by mass of the rubber component is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, still more preferably 80 parts by mass or less, further preferably 70 parts by mass or less, and particularly preferably 60 parts by mass or less.

[0057] (b) SBR The weight average molecular weight of SBR is, for example, more than 100,000 and less than 2 million. The styrene content of SBR is preferably more than 5% by mass, more preferably more than 10% by mass, and still more preferably more than 15% by mass. On the other hand, it is preferably less than 40% by mass, more preferably less than 35% by mass, and still more preferably less than 30% by mass. The vinyl content (amount of 1,2-bonded butadiene units) of SBR is preferably more than 5% by mass, more preferably more than 10% by mass, and still more preferably more than 15% by mass. On the other hand, it is preferably less than 70% by mass, more preferably less than 40% by mass, and still more preferably less than 30% by mass. The structure identification of SBR (measurement of styrene content and vinyl content) can be carried out using, for example, an apparatus of the JNM-ECA series manufactured by JEOL Ltd.

[0058] The SBR is not particularly limited, and for example, emulsion polymerization styrene butadiene rubber (E-SBR), solution polymerization styrene butadiene rubber (S-SBR), etc. can be used. The SBR may be either unmodified SBR or modified SBR. Further, hydrogenated SBR in which the butadiene part in the SBR is hydrogenated may be used, and the hydrogenated SBR may be obtained by post-hydrogenation treatment of the BR part in the SBR, or styrene, ethylene, and butadiene may be copolymerized to obtain a similar structure.

[0059] As the modified SBR, it is preferably SBR having a functional group that interacts with a filler such as silica. For example, a terminal-modified SBR in which at least one terminal of the SBR is modified with a compound (modifying agent) having the above functional group (terminal-modified SBR having the above functional group at the terminal), a main-chain modified SBR having the above functional group in the main chain, a main-chain terminal-modified SBR having the above functional group in the main chain and at the terminal (for example, a main-chain terminal-modified SBR having the above functional group in the main chain and at least one terminal modified with the above modifying agent), and a terminal-modified SBR modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and having a hydroxyl group or an epoxy group introduced therein, etc. can be mentioned.

[0060] Examples of the above functional group include an amino group, an amide group, a silyl group, an alkoxysilyl group, an isocyanate group, an imino group, an imidazole group, a urea group, an ether group, a carbonyl group, an oxycarbonyl group, a mercapto group, a sulfide group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazo group, an azo group, a diazo group, a carboxyl group, a nitrile group, a pyridyl group, an alkoxy group, a hydroxyl group, an oxy group, an epoxy group, etc. Note that these functional groups may have substituents.

[0061] Further, as the modified SBR, for example, SBR modified with a compound (modifying agent) represented by the following formula can be used.

[0062]

Chemical formula

[0063] In the formula, R 1 , R 2 and R 3 are the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH), or a derivative thereof. R 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group. R 4 and R 5 may combine to form a ring structure together with a nitrogen atom. n represents an integer.

[0064] As the modified SBR modified with the compound (modifying agent) represented by the above formula, SBR obtained by modifying the polymerization terminal (active terminal) of solution-polymerized styrene-butadiene rubber (S-SBR) with the compound represented by the above formula (modified SBR described in JP-A-2010-111753, etc.) can be used.

[0065] R 1 , R 2 and R 3 is preferably an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms). R 4 and R 5 is preferably an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and still more preferably 3. Also, when R 4 and R 5 combine to form a ring structure together with a nitrogen atom, it is preferably a 4- to 8-membered ring. The alkoxy group includes a cycloalkoxy group (such as a cyclohexyloxy group) and an aryloxy group (such as a phenoxy group and a benzyloxy group).

[0066] Specific examples of the above-mentioned modifier include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, and the like. These may be used alone or in combination of two or more.

[0067] In addition, as the modified SBR, modified SBR modified with the following compounds (modifying agents) can also be used. Examples of the modifying agent include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine, 4,4'-diglycidyl-dibenzylmethylamine; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl orthotoluidine, tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamic acid chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamic acid chloride, N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane, (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide and other sulfide group-containing silane compounds; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; alkoxysilanes such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyltriethoxysilane; (thio)benzophenone compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone; benzaldehyde compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-t-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam; in addition, N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-triones, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylethyleneurea, 1,3-divinylethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone and the like can be mentioned. The modification with the above compounds (modifying agents) can be carried out by known methods.;

[0068] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., ENEOS MATERIALS Co., Ltd., Asahi Kasei Corporation, Nippon Zeon Co., Ltd. and the like can be used. The SBR may be used alone or in combination of two or more kinds.;

[0069] The content of SBR in 100 parts by mass of the rubber component is preferably 10 parts by mass or more, more preferably 25 parts by mass or more, and still more preferably 40 parts by mass or more. The upper limit is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and still more preferably 55 parts by mass or less.;

[0070] (c) BR The weight average molecular weight of BR is, for example, more than 100,000 and less than 2,000,000. The vinyl content of BR is, for example, more than 1% by mass and less than 30% by mass. The cis content of BR is, for example, more than 1% by mass and 98% by mass or less. The trans content of BR is, for example, more than 1% by mass and less than 60% by mass. The cis content can be measured by infrared absorption spectroscopy.;

[0071] BR is not particularly limited, and BR with a high cis content (cis content of 90% or more), BR with a low cis content, BR containing syndiotactic polybutadiene crystals, etc. can be used. BR can be either unmodified BR or modified BR. As the modified BR, for example, BR modified with a compound (modifying agent) represented by the following formula can be used.

[0072]

Chemical formula

[0073] In the formula, R 1 , R 2 and R 3 are the same or different and represent an alkyl group, an alkoxy group, a silyloxy group, an acetal group, a carboxyl group (-COOH), a mercapto group (-SH), or a derivative thereof. R 4 and R 5 are the same or different and represent a hydrogen atom or an alkyl group. R 4 and R 5 may combine to form a ring structure together with a nitrogen atom. n represents an integer.

[0074] Examples of the modified BR modified with the compound (modifying agent) represented by the above formula include BR in which the polymerization terminal (active terminal) is modified with the compound represented by the above formula.

[0075] R 1 , R 2 and R 3 are preferably alkoxy groups (preferably alkoxy groups having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms). R 4 and R 5 are preferably alkyl groups (preferably alkyl groups having 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and still more preferably 3. Also, R 4 and R 5When they combine to form a ring structure together with a nitrogen atom, it is preferably a 4- to 8-membered ring. The alkoxy group includes a cycloalkoxy group (such as a cyclohexyloxy group), an aryloxy group (such as a phenoxy group, a benzyloxy group), etc.

[0076] Specific examples of the above-mentioned modifier include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, etc. These may be used alone or in combination of two or more.

[0077] In addition, as the modified BR, modified BR modified with the following compounds (modifying agents) can also be used. Examples of the modifying agent include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerin triglycidyl ether, trimethylolethane triglycidyl ether, trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidylated bisphenol A; polyepoxy compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine, 4,4'-diglycidyl-dibenzylmethylamine; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl orthotoluidine, tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamic acid chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamic acid chloride, N,N-diethylcarbamic acid chloride; epoxy group-containing silane compounds such as 1,3-bis-(glycidyloxypropyl)-tetramethyldisiloxane, (3-glycidyloxypropyl)-pentamethyldisiloxane;(Trimethylsilyl)[3-(trimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldipropoxysilyl)propyl]sulfide, (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide and other sulfide group-containing silane compounds; N-substituted aziridine compounds such as ethyleneimine and propyleneimine; alkoxysilanes such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethyltriethoxysilane; (thio)benzophenone compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-t-butylaminobenzophenone, 4-N,N-diphenylaminobenzophenone, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(diphenylamino)benzophenone, N,N,N',N'-bis-(tetraethylamino)benzophenone; benzaldehyde compounds having an amino group and / or a substituted amino group such as 4-N,N-dimethylaminobenzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde; N-substituted pyrrolidones such as N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-t-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone; N-substituted piperidones such as N-methyl-2-piperidone, N-vinyl-2-piperidone, N-phenyl-2-piperidone;N-substituted lactams such as N-methyl-ε-caprolactam, N-phenyl-ε-caprolactam, N-methyl-ω-laurolactam, N-vinyl-ω-laurolactam, N-methyl-β-propiolactam, N-phenyl-β-propiolactam; In addition, N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tris-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-triones, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethyl ethyleneurea, 1,3-divinyl ethyleneurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone and the like can be mentioned. The modification with the above compounds (modifying agents) can be carried out by known methods. These modified BRs may be used alone or in combination of two or more.;

[0078] As the BR, for example, products of Ube Industries, Ltd., ENEOS MATERIALS Co., Ltd., Asahi Kasei Corporation, Nippon Zeon Co., Ltd. and the like can be used.

[0079] The upper limit of the content of BR in 100 parts by mass of the rubber component is preferably 30 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 5 parts by mass or less.

[0080] (ii) Other rubber components The rubber composition may contain, as other rubber components, rubber (polymers) generally used in the production of tires such as nitrile rubber (NBR), if necessary.

[0081] The raw materials (monomers) of the synthetic rubbers such as IR, SBR, and BR described above may be derived from underground resources such as petroleum and natural gas, or may be recycled from rubber products such as tires and non-rubber products such as polystyrene.

[0082] The monomers obtained by recycling (recycled monomers) are not particularly limited, and examples include polyisoprene derived from recycling, butadiene derived from recycling, and aromatic vinyl derived from recycling. Examples of the butadiene include 1,2-butadiene and 1,3-butadiene. The aromatic vinyl is not particularly limited, and examples include styrene. Among them, it is preferable to use polyisoprene derived from recycling (recycled isoprene), butadiene (recycled butadiene) and / or styrene derived from recycling (recycled styrene) as raw materials.

[0083] The method for producing recycled monomers is not particularly limited, and examples include being synthesized from recycled naphtha obtained by decomposing rubber products such as tires. Further, the method for producing recycled naphtha is not particularly limited, and for example, rubber products such as tires may be decomposed under high temperature and high pressure, decomposed by microwaves, or extracted after mechanical pulverization.

[0084] Furthermore, the raw materials (monomers) of synthetic rubbers such as IR, SBR, and BR may be derived from biomass. In this specification, biomass refers to substances derived from natural resources such as plants. The biomass is not particularly limited, and examples include agricultural and forestry products, sugars, wood chips, plant residues after obtaining useful components, ethanol derived from plants, and biomass naphtha.

[0085] The biomass-derived monomers (biomass monomers) are not particularly limited, and examples thereof include biomass-derived butadiene and biomass-derived aromatic vinyls. Examples of the butadiene include 1,2-butadiene and 1,3-butadiene. The aromatic vinyl is not particularly limited, and examples thereof include styrene. Further, the method for producing the biomass monomer is not particularly limited, and examples thereof include those by biological and / or chemical and / or physical conversion of animals and plants. Fermentation by microorganisms is typical as the biological conversion, and examples of the chemical and / or physical conversion include those by a catalyst, high heat, high pressure, electromagnetic waves, a critical liquid, and combinations thereof.

[0086] The polymers synthesized from the biomass monomer components (biomass polymers) are not particularly limited, and examples thereof include polybutadiene rubber synthesized from biomass-derived butadiene, and aromatic vinyl / butadiene copolymers synthesized from biomass-derived butadiene and / or biomass-derived aromatic vinyls. Examples of the aromatic vinyl / butadiene copolymer include styrene butadiene rubber synthesized from biomass-derived butadiene and / or biomass-derived styrene.

[0087] Whether the raw material of the polymer is derived from biomass can be determined by pMC (percent Modern Carbon) measured in accordance with ASTM D6866-10.

[0088] pMC is the ratio of the 14 C concentration of the sample to the 14 C concentration of the standard modern carbon (modern standard reference), and is a value used as an index indicating the biomass ratio of a compound. The significance of this value will be described below.

[0089] In one mole (6.02 × 10 23 pieces) of carbon atoms, there are about 6.02 × 10 11 pieces, which is about one trillionth of ordinary carbon atoms, of 14C exists. 14 C is called a radioactive isotope, and its half-life is 5730 years and it decreases regularly. It takes 226,000 years for all of these to decay. Therefore, after carbon dioxide in the atmosphere and the like are taken up and fixed by plants and the like, in fossil fuels such as coal, oil, and natural gas, for which it is considered that more than 226,000 years have passed, at the beginning of fixation, it was also included in these 14 All of the C element has decayed. Therefore, at present in the 21st century, in fossil fuels such as coal, oil, and natural gas 14 No C element is contained at all. Therefore, in chemical substances produced using these fossil fuels as raw materials 14 No C element is contained at all.

[0090] On the other hand, 14 C is constantly generated by nuclear reactions of cosmic rays in the atmosphere, and is in balance with the decrease due to radioactive decay. In the earth's atmospheric environment, 14 The amount of C is a constant amount. Therefore, for substances derived from biomass resources that are circulating in the current environment 14 The C concentration is about 1×10 -12 mol% with respect to the total C atoms as described above. Therefore, by utilizing the difference between these values, the biomass ratio in a certain compound can be calculated.

[0091] This 14 C is generally measured as follows. Using accelerator mass spectrometry based on a tandem accelerator, 13 C concentration ( 13 C / 12 C), 14 C concentration ( 14 C / 12 C) is measured. In the measurement, 14 As a modern standard reference for the concentration of C, in the circulating carbon in nature at the time of 1950 14The C concentration is adopted. As a specific reference substance, the oxalic acid standard provided by NIST (National Institute of Standards and Technology) is used. The specific radioactivity of carbon in this oxalic acid (radioactivity intensity of 14 C per 1 g of carbon) is separated for each carbon isotope, 13 and for 14 C, it is corrected to a fixed value, and the value after applying the decay correction from 1950 AD to the measurement date is used as the standard

[0092] C concentration value (100%). The ratio of this value to the value of the actually measured sample is the pMC value.

[0093] Therefore, if the rubber is made of a 100% biomass (natural system) - derived material, although there are regional differences, etc., it usually does not reach 100 under normal conditions at present, so it will show a value of approximately 110 pMC. On the other hand, for chemical substances derived from fossil fuels such as petroleum, when this

[0094] (b) Blending materials other than the rubber component (i) Filler The rubber composition preferably contains silica or carbon black as a reinforcing agent, but may contain other fillers as required, for example, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc. When using silica, it is preferably used in combination with a silane coupling agent.

[0095] The compounding amount of the filler is preferably 60 parts by mass or more, more preferably 80 parts by mass or more, and even more preferably 110 parts by mass or more with respect to 100 parts by mass of the rubber component. On the other hand, from the viewpoint of dispersibility in the rubber composition, it is preferably 150 parts by mass or less, and more preferably 140 parts by mass or less.

[0096] (i) Silica Since silica has OH groups on its surface, by containing a large amount, hydrogen bonds are generated between silica surfaces and also interact with the rubber component. Therefore, during driving, force can be easily generated and transmitted inside the rubber, making it easier to transmit the force generated during turning, and excellent handling stability can be ensured. In addition, the OH groups on the surface can capture ozone, so the ozone resistance is improved and the durability of the tire can be improved. The content of silica is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and even more preferably 90 parts by mass or more with respect to 100 parts by mass of the rubber component. The upper limit is preferably 150 parts by mass or less, and more preferably 130 parts by mass or less.

[0097] The BET specific surface area of silica is preferably more than 100 m 2 / g, and more preferably more than 130 m 2 / g. On the other hand, it is preferably less than 250 m 2 / g, and more preferably less than 200 m 2 / g. The above-mentioned BET specific surface area is the value of N2SA measured by the BET method according to ASTM D3037-93.

[0098] Silica is not particularly limited. For example, silica prepared by the dry method (anhydrous silica), silica prepared by the wet method (hydrous silica), etc., which are common in the tire industry, can be used. As commercially available products, products of Evonik Industries, Rhodia, Tosoh Silica Corporation, Solvay Japan Co., Ltd., Tokuyama Corporation, etc. can be used.

[0099] The raw material of silica is not particularly limited. For example, it may be a raw material derived from minerals such as quartz, or it may be a raw material derived from organisms such as rice husks (for example, silica obtained from biomass materials such as rice husks), or silica recycled from products containing silica may also be used. Among them, hydrous silica prepared by the wet method is preferred because it has many silanol groups. However, sustainable silica (silica made from biomass materials or silica recycled from products containing silica) is preferred.

[0100] Silica made from biomass materials can be obtained, for example, by extracting silicate from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and reacting the silicate with sulfuric acid in the same manner as conventional wet silica to obtain a precipitate of silicon dioxide, which is then filtered, washed with water, dried, and pulverized.

[0101] Silica recycled from products containing silica can be used, for example, silica recovered from products containing silica such as electronic components such as semiconductors, tires, desiccants, and filter materials such as diatomaceous earth. Also, the recovery method is not particularly limited, and examples include pyrolysis and decomposition by electromagnetic waves. Among them, silica recovered from electronic components such as semiconductors or tires is preferred.

[0102] When silica crystallizes, it is insoluble in water and the silicic acid that is its component cannot be utilized. By controlling the combustion temperature and combustion time, crystallization of silica in rice husk ash can be suppressed (see, for example, Japanese Patent Laid-Open No. 2009-2594, Akita Prefectural University Web Journal B / 2019, vol. 6, p. 216-222, etc.).

[0103] Amorphous silica extracted from rice husks can be those commercially available from companies such as Wilmar.

[0104] These silicas may be used alone or in combination of two or more. Using biomass silica or recycled silica is preferable from the viewpoint of environmental protection (sustainability).

[0105] (ii) Silane coupling agent When using silica, it is preferable to use a silane coupling agent in combination to enhance the dispersibility of silica and improve mechanical properties and moldability through reaction with silica.

[0106] The silane coupling agent is not particularly limited. For example, bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(2-triethoxysilylethyl)trisulfide, bis(4-trimethoxysilylbutyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, bis(4-trimethoxysilylbutyl)disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, etc. sulfide-based, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, mercapto-based such as NXT and NXT-Z manufactured by Momentive, vinyl-based such as vinyltriethoxysilane and vinyltrimethoxysilane, amino-based such as 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane, glycidoxy-based such as γ-glycidoxypropyltriethoxysilane and γ-glycidoxypropyltrimethoxysilane, nitro-based such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane, chloro-based such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane, etc. can be mentioned. Among these, a silane coupling agent having a thiocarbonyl group such as the above-mentioned NXT is preferred. These may be used alone or in combination of two or more.

[0107] As the silane coupling agent, for example, products of Evonik Industries, Momentive, Shin-Etsu Silicone Co., Ltd., Tokyo Chemical Industry Co., Ltd., Azmax Co., Ltd., Toray Dow Corning Co., Ltd. etc. can be used.

[0108] The content of the silane coupling agent is preferably more than 2 parts by mass, more preferably 3 parts by mass or more, and still more preferably 5 parts by mass or more with respect to 100 parts by mass of silica. As the upper limit, it is preferably less than 15 parts by mass, more preferably 12 parts by mass or less, and still more preferably 9 parts by mass or less.

[0109] (iii) Carbon black Carbon black is preferably used for the purpose of improving the crack growth resistance, durability, ultraviolet degradation resistance, etc. of tires.

[0110] From the viewpoint of the reinforcing property to rubber, the nitrogen adsorption specific surface area (N2SA) of carbon black is preferably 30 m 2 / g or more, more preferably 50 m 2 / g or more, and still more preferably 60 m 2 / g or more. On the other hand, from the viewpoint of heat generation property, it is preferably 250 m 2 / g or less, more preferably 150 m 2 / g or less, and still more preferably 120 m 2 / g or less. The nitrogen adsorption specific surface area of carbon black is measured according to ASTM D4820-93.

[0111] From the viewpoint of the rigidity of rubber, the dibutyl phthalate (DBP) absorption amount of carbon black is preferably 50 ml / 100 g or more, more preferably 100 ml / 100 g or more. On the other hand, from the viewpoint of the followability to the deformation of rubber, it is preferably 250 ml / 100 g or less, more preferably 150 ml / 100 g or less. The DBP absorption amount of carbon black is measured according to ASTM D2414-93.

[0112] The carbon black is not particularly limited, and examples include furnace black (furnace carbon black) such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black (acetylene carbon black); thermal black (thermal carbon black) such as FT and MT; channel black (channel carbon black) such as EPC, MPC, and CC. Also, examples of the product numbers include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. These may be used alone or in combination of two or more.

[0113] In addition to mineral oil, the raw material of carbon black may be biomass materials such as lignin and vegetable oil, or may be pyrolysis oil obtained by pyrolyzing rubber products containing carbon black such as waste tires (recycled carbon black). It is preferable to use sustainable carbon black (carbon black whose raw material is biomass material or recycled carbon black) as the carbon black.

[0114] Also, the production method of carbon black may be by combustion such as the furnace method, by hydrothermal carbonization (HTC), or by thermal decomposition of methane by the thermal black method or the like.

[0115] As commercially available products, products of Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Corporation, Lion Corporation, Nippon Steel Carbon Co., Ltd., Columbian Carbon Company, etc. can be used. These may be used alone or in combination of two or more.

[0116] The content of carbon black relative to 100 parts by mass of the rubber component is preferably 5 parts by mass or more, more preferably 10 parts by mass or more. The upper limit is preferably 30 parts by mass or less, more preferably 25 parts by mass or less.

[0117] (iv) Rubber powder The vulcanized rubber particles are particles made of vulcanized rubber. Specifically, rubber powder defined in JIS K 6316:2017 can be used. From the perspectives of environmental consideration and cost, recycled rubber powder produced from crushed waste tires is preferred. These may be used alone or in combination of two or more.

[0118] (v) Other fillers In addition to the above-mentioned carbon black and silica, the rubber composition may further contain fillers generally used in the tire industry, such as graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, magnesium sulfate, etc. When these are contained, the content is, for example, more than 0.1 part by mass and less than 150 parts by mass with respect to 100 parts by mass of the rubber component.

[0119] (b) Softening agent component In the rubber composition, from the viewpoint of imparting plasticity to the rubber component and appropriately dispersing the powder material during kneading, it is preferable to use a softening agent component as needed. Here, the softening agent component is a concept including both softening agents that are liquid at 25°C and softening agents that are solid at 25°C.

[0120] Examples of the softening agent include resin components, oils, liquid polymers, ester plasticizers, etc. These softening agents may be derived from mineral resources such as petroleum and natural gas, may be derived from biomass, or may be derived from recycled naphtha from rubber products or non-rubber products. Also, low-molecular-weight hydrocarbon components obtained by pyrolyzing and extracting used tires and products containing various components may be used as softening agents. Among these, softening agents derived from biomass or recycling are preferred as sustainable softening agents.

[0121] In addition, these softeners may be used alone or in combination of two or more. The content of the plasticizer component with respect to 100 parts by mass of the rubber component is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and still more preferably 7 parts by mass or more. The upper limit is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and still more preferably 15 parts by mass or less. Note that the content of the plasticizer component includes the amount of oil contained in rubber (oil-extended rubber) and the like.

[0122] (i) Oil Examples of the oil include mineral oil, vegetable oil, and animal oil. Also, from the perspective of life cycle assessment, waste oil after use in a rubber mixer or engine, or refined waste cooking oil used in a restaurant may be used.

[0123] (i-1) Mineral oil In this specification, the mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of the mineral oil include paraffinic oil (mineral oil), naphthenic oil, and aromatic oil.

[0124] Specific examples of the mineral oil include MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), RAE (Residual Aromatic Extract), and the like.

[0125] Also, an oil with a low content of polycyclic aromatic (PCA) compounds can be used for environmental protection. Examples of the low-PCA-content oil include MES, TDAE, and heavy naphthenic oil.

[0126] Examples of commercially available mineral oils include oils such as paraffinic, aromatic, and naphthenic oils. For example, products of Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Orisoy Co., H&R Co., Toyokuni Oil Co., Ltd., Showa Shell Sekiyu K.K., Fuji Kogyo Co., Ltd., etc. can be used. These may be used alone or in combination of two or more.

[0127] (i-2) Vegetable oil Examples of vegetable oils include linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, perilla oil, castor oil, tung oil, pine oil, pine tar oil, sunflower oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grape seed oil, wood wax, etc.

[0128] Furthermore, examples of vegetable oils include refined oils (such as salad oil) obtained by refining each of the above oils, transesterified oils obtained by transesterification, hydrogenated hardened oils, thermally polymerized oils obtained by thermal polymerization, oxidation polymerized oils obtained by oxidation, and waste cooking oils recovered from those used as edible oils, etc. Note that vegetable oils may be liquid or solid at room temperature (25°C). These may be used alone or in combination of two or more.

[0129] Vegetable oils preferably contain acylglycerol, and more preferably contain triacylglycerol. Note that acylglycerol refers to a compound in which the hydroxy group of glycerin and a fatty acid are ester-bonded. Acylglycerol is not particularly limited and may be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, acylglycerol may be a monomer, a dimer, or a multimer of three or more. Note that acylglycerol dimers or more can be obtained by thermal polymerization, oxidation polymerization, etc. Also, acylglycerol may be liquid or solid at room temperature (25°C).

[0130] As a method for confirming whether acylglycerol is contained in the rubber composition, it is not particularly limited, but 1 it can be confirmed by 1H-NMR measurement. For example, a rubber composition containing triacylglycerol is immersed in deuterated chloroform at room temperature (25 °C) for 24 hours. After removing the rubber composition, at room temperature 1 1H-NMR is measured. When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals are observed around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm. Since these signals are presumed to be signals derived from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group, the content of acylglycerol can be confirmed. Here, "around" refers to the range of ±0.10 ppm.

[0131] The fatty acid is not particularly limited and may be an unsaturated fatty acid or a saturated fatty acid. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0132] Among them, as the fatty acid, it is desirable to contain a fatty acid with few double bonds, that is, a saturated fatty acid or a monounsaturated fatty acid, and oleic acid is preferred. As the vegetable oil containing such a fatty acid, for example, a vegetable oil containing a saturated fatty acid or a monounsaturated fatty acid may be used, or a modified vegetable oil obtained by transesterification or the like may be used. In addition, in order to produce a vegetable oil containing such a fatty acid, plants may be improved by variety improvement, genetic recombination, genome editing, or the like.

[0133] As the vegetable oil, for example, those commercially available from Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., Orisoy Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., Nisshin Oillio Group Co., Ltd., etc. can be used.

[0134] (ii) Liquid rubber Liquid rubber is a polymer in a liquid state at room temperature (25 °C) and is a rubber component that can be extracted from a vulcanized tire by acetone extraction. Examples of liquid rubber include farnesene-based polymers, liquid diene-based polymers, and hydrogenated products thereof.

[0135] A farnesene-based polymer is a polymer obtained by polymerizing farnesene and has a structural unit based on farnesene. Farnesene has isomers such as α-farnesene ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecatetraene) and β-farnesene (7,11-dimethyl-3-methylene-1,6,10-dodecatriene).

[0136] The farnesene-based polymer may be a homopolymer of farnesene (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer).

[0137] Examples of liquid diene-based polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), liquid styrene-isoprene copolymer (liquid SIR), and the like.

[0138] The liquid diene-based polymer has a polystyrene-equivalent weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of, for example, less than 1.0×10 3 super, 2.0×10 5 Here, the Mw of the liquid diene-based polymer is a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0139] As the liquid rubber, for example, products of Kuraray Co., Ltd., Kraiburg Co., etc. can be used.

[0140] (iii) Resin component The resin component also functions as an adhesiveness-imparting component and may be solid or liquid at normal temperature. Specific resin components include, for example, rosin-based resins, styrene-based resins, coumarone-based resins, terpene-based resins, C5 resins, C9 resins, C5C9 resins, acrylic resins, etc. Two or more of them may be used in combination. In addition, these resin components may be provided with a modifying group capable of reacting with silica or the like as necessary. The blending amount of the resin component is preferably 1 to 10 parts by mass or less, more preferably 2 to 6 parts by mass or less, based on 100 parts by mass of the rubber component.

[0141] The rosin-based resin is a resin mainly composed of rosin acid obtained by processing pine resin. This rosin-based resin (rosins) can be classified according to the presence or absence of modification, and can be classified into unmodified rosin (non-modified rosin) and rosin modified products (rosin derivatives). Examples of unmodified rosin include tall rosin (also known as tall oil rosin), gum rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins. Rosin modified products are modified products of unmodified rosin, and examples include rosin esters, unsaturated carboxylic acid-modified rosins, unsaturated carboxylic acid-modified rosin esters, amide compounds of rosin, and amine salts of rosin.

[0142] The styrene-based resin is a polymer using a styrene-based monomer as a constituent monomer, and examples include polymers polymerized with a styrene-based monomer as a main component (50% by mass or more). Specifically, homopolymers obtained by polymerizing each styrene-based monomer (styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.) alone, copolymers obtained by copolymerizing two or more styrene-based monomers, and copolymers of a styrene-based monomer and other monomers copolymerizable therewith are also included.

[0143] Examples of the other monomer include acrylonitriles such as acrylonitrile and methacrylonitrile, acrylates, unsaturated carboxylic acids such as methacrylic acid, unsaturated carboxylic acid esters such as methyl acrylate and methyl methacrylate, dienes such as chloroprene, butadiene and isoprene, olefins such as 1-butene and 1-pentene; α,β-unsaturated carboxylic acids such as maleic anhydride or acid anhydrides thereof; and the like.

[0144] Among coumarone resins, coumarone-indene resins are preferred. A coumarone-indene resin is a resin containing coumarone and indene as monomer components constituting the resin skeleton (main chain). Examples of monomer components contained in the skeleton other than coumarone and indene include styrene, α-methylstyrene, methyl indene, vinyltoluene and the like.

[0145] The hydroxyl value (OH value) of the coumarone-indene resin is, for example, more than 15 mgKOH / g and less than 150 mgKOH / g. The OH value represents the amount of potassium hydroxide in milligrams required to neutralize acetic acid bonded to hydroxyl groups when 1 g of the resin is acetylated, and is a value measured by the potentiometric titration method (JIS K 0070:1992).

[0146] The softening point of the coumarone-indene resin is, for example, more than 30°C and less than 160°C. The softening point is the temperature at which the ball drops when measured with a ring and ball softening point measuring device according to the softening point specified in JIS K 6220-1:2001.

[0147] Examples of terpene resins include polyterpene, terpene phenol, aromatic modified terpene resin and the like. Polyterpene is a resin obtained by polymerizing terpene compounds and hydrogenated products thereof. Terpene compounds are hydrocarbons represented by the composition of (C5H8) n and oxygen-containing derivatives thereof, and include monoterpenes (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H32 ) It is a compound having a terpene as a basic skeleton and classified into, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, allo-ocimene, ocimene, α-farnesene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, etc.

[0148] Examples of polyterpenes include terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, β-pinene / limonene resin, etc. using the above-mentioned terpene compounds as raw materials, and hydrogenated terpene resins obtained by hydrogenating the terpene resins. Examples of terpene phenols include resins obtained by copolymerizing the above-mentioned terpene compounds and phenolic compounds, and resins obtained by hydrogenating the resins. Specifically, resins obtained by condensing the above-mentioned terpene compounds, phenolic compounds and formalin are included. Examples of phenolic compounds include phenol, bisphenol A, cresol, xylenol, etc. Examples of aromatic-modified terpene resins include resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating the resins. The aromatic compound is not particularly limited as long as it has an aromatic ring. Examples include phenolic compounds such as phenol, alkylphenol, alkoxyphenol, and unsaturated hydrocarbon group-containing phenol; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, and unsaturated hydrocarbon group-containing naphthol; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, and unsaturated hydrocarbon group-containing styrene; coumarone, indene, etc.

[0149] "C5 resin" refers to a resin obtained by polymerizing a C5 fraction. Examples of the C5 fraction include petroleum fractions corresponding to 4 to 5 carbon atoms such as cyclopentadiene, pentene, pentadiene, isoprene, etc. As the C5-based petroleum resin, dicyclopentadiene resin (DCPD resin) is preferably used.

[0150] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, which may be hydrogenated or modified. Examples of the C9 fraction include petroleum fractions equivalent to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, and methylindene. As specific examples, for instance, coumarone-indene resin, coumarone resin, indene resin, and aromatic vinyl resins are preferably used. Among the aromatic vinyl resins, α-methylstyrene (AMS resin) or a homopolymer of styrene or a copolymer of α-methylstyrene and styrene is preferred, and a copolymer of α-methylstyrene and styrene is more preferred, because they are economical, easy to process, and excellent in heat generation properties. As the aromatic vinyl resins, those commercially available from companies such as Crayton and Eastman Chemical can be used.

[0151] "C5C9 resin" refers to a resin obtained by copolymerizing the C5 fraction and the C9 fraction, which may be hydrogenated or modified. Examples of the C5 fraction and the C9 fraction include the above-mentioned petroleum fractions. As the C5C9 resins, those commercially available from companies such as Toray Industries, Inc. and LUHUA can be used.

[0152] The acrylic resin is not particularly limited, and for example, a solventless acrylic resin can be used.

[0153] The solventless acrylic resin is a (meth)acrylic resin (polymer) synthesized by a high-temperature continuous polymerization method (high-temperature continuous bulk polymerization method) (the methods described in U.S. Patent No. 4,414,370, JP-A-59-6207, JP-B-5-58005, JP-A-1-313522, U.S. Patent No. 5,010,166, and TREND 2000, No. 3, pp. 42-45 of the Annual Report of Toagosei Co., Ltd., etc.) without using a polymerization initiator, a chain transfer agent, an organic solvent, etc. as auxiliary raw materials as much as possible. Note that "(meth)acrylic" means methacrylic and acrylic.

[0154] Examples of the monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (such as alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0155] As the monomer components constituting the acrylic resin, aromatic vinyls such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used together with (meth)acrylic acid or (meth)acrylic acid derivatives.

[0156] The acrylic resin may be a resin composed only of the (meth)acrylic component or a resin having components other than the (meth)acrylic component as constituent elements. Further, the acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, etc.

[0157] Examples of the resin component include products of Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, Clayton, Nippon Paint Co., Ltd., Nippon Catalyst Co., Ltd., ENEOS Corporation, Arakawa Chemical Industries, Ltd., Tago Chemical Industry Co., Ltd., etc.

[0158] (C) Wax The rubber composition may contain wax. The content of wax is preferably 0.5 to 20 parts by mass, more preferably 1.0 to 15 parts by mass, and even more preferably 1.5 to 10 parts by mass with respect to 100 parts by mass of the rubber component.

[0159] The wax is not particularly limited, and any wax commonly used in the tire industry can be preferably used. Examples include mineral waxes and plant-derived waxes. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Among them, plant-derived waxes are preferred.

[0160] Examples of plant-derived waxes include rice wax, carnauba wax, candelilla wax, etc. Examples of mineral waxes include paraffin wax, microcrystalline wax, and these selected special waxes, etc., and paraffin wax is preferred. Note that stearic acid is not included in the wax.

[0161] Note that as the wax, for example, those commercially available from Ouchi Shinsei Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramoelt Co., etc. can be used. These waxes may be used alone or in combination of two or more.

[0162] (ii) Antioxidant The rubber composition may contain an antioxidant. The content of the antioxidant is, for example, more than 1 part by mass and less than 10 parts by mass with respect to 100 parts by mass of the rubber component.

[0163] The anti-aging agent is not particularly limited, but examples include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; p-phenylenediamine-based anti-aging agents such as N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditoly-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based anti-aging agents such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based anti-aging agents such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; bis, tris, polyphenol-based anti-aging agents such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, etc. Among them, p-phenylenediamine-based anti-aging agents and quinoline-based anti-aging agents are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymers of 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. These may be used alone or in combination of two or more kinds.

[0164] As commercially available products, for example, products of Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Industry Co., Ltd., Flexsys Co., etc. can be used.

[0165] (Co) Processing aids The rubber composition may contain a processing aid. Examples of the processing aid include metal salts (compounds in which the hydrogen atom of an acid is replaced by a metal ion), fatty acid amides, amide esters, fatty acid esters, etc. These may be used alone or in combination of two or more. Among them, metal salts and fatty acid amides are preferred, and metal salts are more preferred.

[0166] Examples of the metal used in the metal salt include alkali metals such as potassium and sodium, alkaline earth metals such as calcium and barium, etc. Further, magnesium, zinc, nickel, molybdenum, etc. can also be used. Among them, alkali metals are preferred.

[0167] Examples of the acid used in the metal salt include fatty acids such as lauric acid, myristic acid, palmitic acid, etc. Further, boric acid, carbonic acid, hydrochloric acid, nitric acid, sulfuric acid, etc. can also be used.

[0168] As commercially available products of the processing aid, products of Kinoshita Chemical Co., Ltd., Ken-etsu Pharmaceutical Co., Ltd., Struktol, Performance Additives, etc. can be used.

[0169] The content of the processing aid is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more with respect to 100 parts by mass of the rubber component. The upper limit is preferably 6 parts by mass or less, more preferably 4 parts by mass or less.

[0170] (F) Lubricant (Stearic acid) The rubber composition may contain a lubricant. As the lubricant, lubricants based on fatty acid derivatives such as stearic acid can be preferably used. As stearic acid, conventionally known ones can be used. Specifically, for example, products of NOF Corporation, Kao Corporation, Fuji Film Wako Pure Chemical Corporation, Chiba Fatty Acids Co., Ltd., etc. can be used. Further, Struktol WB16 manufactured by Struktol can also be used.

[0171] The content of stearic acid is preferably more than 0.5 parts by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component.

[0172] (T) Zinc oxide The rubber composition may contain zinc oxide. The content of zinc oxide is, for example, more than 0.5 part by mass and less than 10 parts by mass with respect to 100 parts by mass of the rubber component. As the zinc oxide, conventionally known ones can be used, for example, products of Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., Hakusui Tech Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

[0173] (d) Crosslinking agent and vulcanization accelerator The rubber composition preferably contains a crosslinking agent such as sulfur. The content of the crosslinking agent is, for example, more than 0.1 part by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component. Note that the content of sulfur is the pure sulfur content, and when insoluble sulfur is used, it is the content excluding the oil component.

[0174] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, soluble sulfur, etc. generally used in the rubber industry. These may be used alone or in combination of two or more.

[0175] Note that as sulfur, for example, products of Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexsys, Nippon Kankyu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

[0176] Crosslinking agents other than sulfur may be used. Specifically, for example, Tackiol V200 manufactured by Tago Chemical Industry Co., Ltd., DURALINK HTS (sodium 1,6 - hexamethylene - dithiolsulfate dihydrate) manufactured by Flexsys, KA9188 (1,6 - bis(N,N’ - dibenzylthiocarbamoyldithio)hexane: hybrid crosslinking agent) manufactured by Rancess, etc., sulfur - containing vulcanizing agents, and organic peroxides such as dicumyl peroxide can be used.

[0177] And the rubber composition preferably contains a vulcanization accelerator. The content of the vulcanization accelerator is, for example, more than 0.3 part by mass and less than 10.0 parts by mass with respect to 100 parts by mass of the rubber component.

[0178] Examples of the vulcanization accelerator include thiazole - type vulcanization accelerators such as 2 - mercaptobenzothiazole, di - 2 - benzothiazolyldisulfide, N - cyclohexyl - 2 - benzothiazylsulfenamide; thiuram - type vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), tetrakis(2 - ethylhexyl)thiuram disulfide (TOT - N); sulfenamide - type vulcanization accelerators such as N - cyclohexyl - 2 - benzothiazole sulfenamide, N - t - butyl - 2 - benzothiazolylsulfenamide, N - oxyethylene - 2 - benzothiazole sulfenamide, N - oxyethylene - 2 - benzothiazole sulfenamide, N,N’ - diisopropyl - 2 - benzothiazole sulfenamide; and guanidine - type vulcanization accelerators such as diphenylguanidine, di - ortho - tolylguanidine, ortho - tolylbiguanidine. These can be used alone or in combination of two or more.

[0179] (V) Others In addition to the above - mentioned components, the rubber composition may be blended with additives generally used in the tire industry, such as organic fillers like cellulose fibers, organic peroxides, etc., as required. The content of these additives is, for example, more than 0.1 part by mass and less than 50 parts by mass with respect to 100 parts by mass of the rubber component.

[0180] Among the above - mentioned various materials, various materials containing carbon atoms (such as rubber, oil, resin, vulcanization accelerator, anti - aging agent, surfactant, etc.) may be derived from carbon dioxide in the atmosphere. As a method for obtaining the formulation of the present invention from carbon dioxide, carbon dioxide may be directly converted, or methane obtained through the methanation step of synthesizing methane from carbon dioxide may be converted.

[0181] After treating the band cord with an adhesive and then adhering it to a predetermined rubber composition for the band, a band can be obtained.

[0182] (2) Preparation of the rubber composition The rubber composition can be produced by a production method including a base kneading step of kneading a rubber component and a filler such as silica by a general method, and a finishing kneading step of kneading the kneaded product obtained in the base kneading step and a crosslinking agent.

[0183] Kneading can be carried out using a known (closed-type) kneader such as a Banbury mixer, a kneader, an open roll, etc.

[0184] The kneading temperature in the base kneading step is, for example, above 50°C and below 200°C, and the kneading time is, for example, above 30 seconds and below 30 minutes. In the base kneading step, in addition to the above components, compounding agents conventionally used in the rubber industry, such as softening agents such as oil, stearic acid, zinc oxide, anti-aging agents, waxes, vulcanization accelerators, etc., may be appropriately added and kneaded as necessary.

[0185] In the finishing kneading step, the kneaded product obtained in the base kneading step and a crosslinking agent are kneaded. The kneading temperature in the finishing kneading step is, for example, above room temperature and below 80°C, and the kneading time is, for example, above 1 minute and below 15 minutes. In the finishing kneading step, in addition to the above components, vulcanization accelerators, zinc oxide, etc. may be appropriately added and kneaded as necessary.

[0186] 3. Tire manufacturing The tire according to this embodiment can be manufactured by a normal method. First, using the rubber composition obtained as described above, a tread is formed so that the rubber hardness (Shore hardness) Hs is above 70 pt as described above. As a method for adjusting the rubber hardness (Shore hardness) Hs of the tread, for example, by increasing the blending amount of fillers such as silica and carbon in the rubber composition, increasing the blending amount of the crosslinking agent, or decreasing the blending amount of plasticizers (such as oil and resin), the rubber hardness (Shore hardness) Hs of the tread can be increased. The tread can be formed, for example, by extrusion. Next, it is combined with other rubber members on a tire molding machine to produce an unvulcanized tire.

[0187] Specifically, on the forming drum, an inner liner as a member for ensuring the airtightness of the tire, a carcass as a member for withstanding the load, impact, and inflation air pressure received by the tire, a belt member as a member for strongly clamping the carcass to increase the rigidity of the tread, a band, etc. are wound, both ends of the carcass are fixed to both side edges, and a bead portion as a member for fixing the tire to the rim is arranged. After forming into a toroidal shape, a tread is attached to the central portion of the outer periphery, and a sidewall is bonded to the radially outer side to form a side portion, thereby producing an unvulcanized tire. As described above, in the tire according to the present embodiment, the carcass is formed in a single-layer structure using a carcass cord with a total fineness exceeding 2400 dtex. Further, as the band cord constituting the band, a cord obtained by single-twisting (1×4 structure) a filament having a circular cross-section without corrugating is used.

[0188] Thereafter, the unvulcanized tire produced as described above is heated and pressurized in a vulcanizer to obtain a tire. The vulcanization process can be carried out by applying known vulcanization means. The vulcanization temperature is, for example, above 120°C and below 200°C, and the vulcanization time is, for example, above 5 minutes and below 15 minutes.

[0189] As described above, the tire obtained as above appropriately controls the sum of the diameter Bar (mm) of the band cord, the diameter Ber (mm) of the belt cord, the diameter Car (mm) of the carcass cord, and the thickness Trg (mm) of the tread, so that the effect of using the PET band and the effects of the appropriately formed tread and carcass cooperate to improve the overall performance of low fuel consumption and high-speed durability.

[0190] And the tire according to the present invention can be preferably used as a passenger car tire, a large passenger car tire, a large SUV tire, a truck and bus tire, a motorcycle tire, a racing tire, a studless tire (winter tire), an all-season tire, a run-flat tire, etc., and particularly preferably as a passenger car tire.

Example

[0191] Hereinafter, examples (embodiments) considered preferable in implementation are shown, but the scope of the present invention is not limited to such embodiments.

[0192] A tire (tire size: 195 / 65R15) composed of a tread formed from various compounding materials shown below and tire members such as bands and belts is considered, and the results calculated based on the evaluation methods described later regarding low fuel consumption and high-speed durability are shown together at the bottom of Table 1.

[0193] 1. Preparation of rubber composition Using the various compounding materials shown below, a rubber composition for a tread is prepared.

[0194] (1) Compounding materials (a) Rubber components (i) NR: TSR20 (ii) SBR: HPR840 manufactured by ENEOS Materials (Styrene content: 10% by mass, vinyl content: 42 mol%, Tg: -60°C, non-oil product) (iii) BR: UBEPOL BR (registered trademark) 150B manufactured by Ube Industries, Ltd.

[0195] (b) Compounding materials other than rubber components (i) Carbon black: DIABLACK N220 manufactured by Mitsubishi Chemical Corporation (N2SA: 115 m 2 / g) (ii) Silica: ULTRASIL VN3 manufactured by Evonik Industries (N2SA: 175 m 2 / g, average primary particle diameter: 17 nm) (iii) Coupling agent: NXT manufactured by Momentive (3-octanoylthiopropyltriethoxysilane) (iv) Oil: Mineral oil A / OMIX manufactured by Sankyo Oil & Chemical Co., Ltd. (v) Resin: YS resin PX850 manufactured by Yasuhara Chemical Co., Ltd. (Softening point 85°C, β-pinene resin (terpene resin)) (Hex) Wax: Oz Ace 0355 manufactured by Nippon Seiko Co., Ltd. (Tor) Antioxidant - 1: Nocrack 6C manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine) (Chi) Antioxidant - 2: ANTAGE RD manufactured by Kawaguchi Chemical Industry Co., Ltd. (Poly(2,2,4-trimethyl-1,2-dihydroquinoline) (Ri) Stearic acid: Bead Stearic acid "Tsubaki" manufactured by NOF Corporation (Nu) Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. (Ru) Sulfur: Powder sulfur manufactured by Karuizawa Sulfur Co., Ltd. (Wo) Vulcanization accelerator - 1: Nocceler CZ manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N-cyclohexylbenzothiazole-2-sulfenamide) (Wa) Vulcanization accelerator - 2: Nocceler D manufactured by Ouchi Shinko Chemical Industry Co., Ltd. (N,N’-diphenylguanidine)

[0196] (2) Preparation of rubber composition for tread Based on each formulation of A to C shown in Table 1, using a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd., materials other than sulfur and vulcanization accelerators are kneaded at 150°C for 5 minutes to obtain a kneaded product.

[0197] Next, sulfur and vulcanization accelerators are added to the kneaded product, and it is kneaded for 5 minutes at 80°C using an open roll to obtain rubber compositions for tread of formulations A to C.

[0198] 2. Molding of tire components (tread, band, belt) (1) Molding of tread Next, using the rubber composition obtained above, the tread is molded at each thickness shown in Table 2.

[0199] (2) Molding of band In parallel, a predetermined rubber composition for band is topped on each band cord shown in Table 2 to mold each band.

[0200] (3) Belt forming Similarly, a predetermined rubber composition for the belt is topped on each belt code shown in Table 2 to form each belt.

[0201] 3. Tire manufacturing Next, each tread, band, and belt obtained above are bonded together with other tire members to form an unvulcanized tire, which is press-vulcanized at 170 °C for 10 minutes to manufacture each test tire of Examples 1 to 4 and Comparative Examples 1 to 6.

[0202] 4. Performance evaluation test (1) High-speed durability evaluation Each test tire is incorporated into a rim (size = 15×6J), the tire is filled with air, and after adjusting the internal pressure to 280 kPa, it is mounted on a drum running tester, a vertical load of 4.22 kN is applied, and the speed is gradually increased from 200 km / h by 10 km / h each time. The time and speed until the tire is damaged are measured. The obtained time is divided by the time required to increase to the next speed, and the value obtained by multiplying by 10 km / h is added to the obtained speed. The index when the result in Comparative Example 1 is set to 100 is used as an index of high-speed durability.

[0203] Next, with the result in Comparative Example 1 set to 100, it is indexed based on the following formula for high-speed durability evaluation. The larger the numerical value, the better the high-speed durability. High-speed durability evaluation = [(result of test tire) / (result of Comparative Example 1)] × 100

[0204] (2) Low fuel consumption evaluation Using a rolling resistance tester, the rolling resistance coefficient (RRC: Rolling Resistance Coefficient) is measured when each test tire runs on a drum at a speed of 80 km / h under the following conditions. Rim used: 15×6J Internal pressure: 210 kPa Load: 4.35 kN

[0205] Next, taking the result in Comparative Example 1 as 100, it is exponentiated based on the following formula for low fuel consumption evaluation. The larger the numerical value, the better the low fuel consumption performance. Low fuel consumption evaluation =[(Result of Comparative Example 1) / (Result of test tire)] × 100

[0206] (3) Comprehensive evaluation Then, (1) and (2) are added together for comprehensive evaluation.

[0207] The evaluation results are shown in Table 2.

[0208]

Table 1

[0209]

Table 2

[0210] As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above embodiments. Various modifications can be made to the above embodiments within the same and equivalent scope as the present invention.

[0211] The present invention (1) is a carcass provided with carcass cords, a belt provided with belt cords and provided on the outer side in the tire radial direction of the carcass, a band provided with band cords and provided on the outer side in the tire radial direction of the belt, a tire comprising a tread provided on the outer side in the tire radial direction of the band, wherein the band cords contain polyethylene terephthalate fibers, the carcass is formed using carcass cords with a total fineness exceeding 2400 dtex, The tread is formed with a rubber hardness (Shore hardness) Hs of over 70 pt using a rubber composition containing over 20 parts by mass of isoprene rubber in 100 parts by mass of a rubber component. Furthermore, a tire characterized in that the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the band cord, the diameter Ber (mm) of the belt cord, the diameter Car (mm) of the carcass cord, and the thickness Trg (mm) of the tread is less than 20.

[0212] The present invention (2) is a tire according to the present invention (1), characterized in that the carcass is formed in a single-layer structure.

[0213] The present invention (3) is a tire according to the present invention (1), characterized in that the belt cord is a cord composed of 1 or more and 4 or less filaments.

[0214] The present invention (4) is a tire according to the present invention (1), characterized in that the rubber hardness (Shore hardness) Hs is over 71 pt.

[0215] The present invention (5) is a tire according to the present invention (4), characterized in that the rubber hardness (Shore hardness) Hs is over 73 pt.

[0216] The present invention (6) is a tire according to the present invention (5), characterized in that the rubber hardness (Shore hardness) Hs is over 75 pt.

[0217] The present invention (7) is a tire according to the present invention (1), characterized in that the ratio (tire weight / maximum load capacity) of the tire weight (kg) to the maximum load capacity (kg) of the tire is less than 0.02.

[0218] The present invention (8) The polyethylene terephthalate fiber is a sustainable polyethylene terephthalate fiber, and the tire is the tire according to the present invention (1).

[0219] The present invention (9) is The rubber composition contains vegetable oil, and the tire is the tire according to the present invention (1).

[0220] The present invention (10) is The rubber composition contains sustainable carbon black, and the tire is the tire according to the present invention (1).

[0221] The present invention (11) is The rubber composition contains sustainable silica, and the tire is the tire according to the present invention (1).

Explanation of symbols

[0222] 1 Tire 2 Tread 3 Sidewall 4 Chafer 5 Bead 6 Inner liner 7 Carcass 8 Belt 9 Filler 10 Band CL Equatorial plane of the tire

Claims

1. A carcass comprising a carcass cord; A belt comprising a belt cord and provided on the outer side in the tire radial direction of the carcass; A band comprising a band cord and provided on the outer side in the tire radial direction of the belt; A tire comprising a tread provided on the outer side in the tire radial direction of the band, wherein the band cord contains polyethylene terephthalate fiber; the carcass is formed using a carcass cord with a total fineness exceeding 2400 dtex; the tread is formed with a rubber hardness (Shore hardness) Hs exceeding 70 pt using a rubber composition containing more than 20 parts by mass of isoprene rubber in 100 parts by mass of the rubber component; furthermore, the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the band cord, the diameter Ber (mm) of the belt cord, the diameter Car (mm) of the carcass cord, and the thickness Trg (mm) of the tread is less than 20. A tire characterized by this.

2. The tire according to Claim 1, wherein the carcass is formed in a single layer structure.

3. The tire according to Claim 1, wherein the belt cord is a cord composed of one or more and four or fewer filaments.

4. The tire according to Claim 1, wherein the rubber hardness (Shore hardness) Hs exceeds 71 pt.

5. The tire according to Claim 4, wherein the rubber hardness (Shore hardness) Hs exceeds 73 pt.

6. The tire according to Claim 5, wherein the rubber hardness (Shore hardness) Hs exceeds 75 pt.

7. The tire according to Claim 1, wherein the ratio (tire weight / maximum load capacity) of the tire weight (kg) to the maximum load capacity (kg) of the tire is less than 0.

02.

8. The tire according to Claim 1, wherein the polyethylene terephthalate fiber is a sustainable polyethylene terephthalate fiber.

9. The tire according to Claim 1, wherein the rubber composition contains vegetable oil.

10. The tire according to Claim 1, wherein the rubber composition contains sustainable carbon black.

11. The tire according to Claim 1, wherein the rubber composition contains sustainable silica.

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