Tire

Abstract

The invention provides a tire capable of improving the comprehensive performance of low fuel consumption and high-speed durability. A tire is provided with: a carcass provided with carcass cords; a belt layer provided with belt layer cords and provided on the outside of the carcass in the tire radial direction; a cap ply provided with a cap ply cord and provided on the outside of the belt layer in the tire radial direction; and a tread provided on the outside of the cap ply in the radial direction of the tire, in which cap ply cords include polyethylene terephthalate fibers, the carcass is formed using carcass cords having a total fineness of more than 2400 dtex, and the tread is provided on the outside of the cap ply in the radial direction of the tire. The tread is formed using a rubber composition containing more than 20 parts by mass of an isoprene rubber in 100 parts by mass of a rubber component such that the rubber hardness (Shore hardness) Hs is more than 70 pt, and the sum (Bar + Ber + Carr + Trg) of the cap ply cord diameter Bar (mm), the belt ply cord diameter Ber (mm), the carcass cord diameter Carr (mm), and the tread thickness Trg (mm) is less than 20.

Description

Technical Field

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

[0002] As described in Patent Document 1, in a passenger car tire, from the aspect of preventing tire deformation caused by centrifugal force during high-speed driving, a crown ply (also called a cap ply) is usually provided between the tread and the belt layer.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-38812 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] The problem of the present invention is to improve the comprehensive performance of low fuel consumption and high-speed durability.

[0008] Means for Solving the Problems

[0009] The present invention relates to a tire, which includes:

[0010] A carcass including carcass cords;

[0011] A belt layer including belt layer cords and disposed radially outside the carcass of the tire;

[0012] A crown ply including crown ply cords and disposed radially outside the belt layer of the tire; and

[0013] A tread disposed radially outside the crown ply of the tire,

[0014] The tire is characterized in that

[0015] The crown ply cords include polyethylene terephthalate fibers,

[0016] The carcass is formed using carcass cords with a total fineness exceeding 2400 dtex,

[0017] The tread is formed using a rubber composition containing more than 20 parts by mass of isoprene rubber in 100 parts by mass of a rubber component to have a rubber hardness (Shore hardness) Hs exceeding 70 pt,

[0018] Furthermore, the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the crown ply cords, the diameter Ber (mm) of the belt layer cords, the diameter Car (mm) of the carcass cords, and the thickness Trg (mm) of the tread is less than 20.

[0019] Advantages of the Invention

[0020] According to the present invention, it is possible to improve the comprehensive performance of low fuel consumption and high-speed durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic cross-sectional view showing the structure of a tire according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] [1] Features of the Tire of the Present Invention

[0023] First, the features of the tire of the present invention will be described.

[0024] 1. Outline

[0025] The tire of the present invention includes: a carcass having carcass cords; a belt layer having belt layer cords and provided on the radially outer side of the carcass in the tire; a crown belt layer having crown belt layer cords and provided on the radially outer side of the belt layer in the tire; and a tread provided on the radially outer side of the crown belt layer in the tire. Further, the crown belt layer cords include polyethylene terephthalate fibers (PET fibers). In addition, the carcass is formed using carcass cords with a total fineness exceeding 2400 dtex. Further, the tread is formed of a rubber composition containing more than 20 parts by mass of isoprene rubber in 100 parts by mass of the rubber component to have a rubber hardness (Shore hardness) Hs exceeding 70 pt. Further, the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the crown belt layer cords, the diameter Ber (mm) of the belt layer cords, the diameter Car (mm) of the carcass cords, and the thickness Trg (mm) of the tread is less than 20.

[0026] By having these features, as described later, it is considered possible to improve the comprehensive performance of low fuel consumption and high-speed durability.

[0027] It should be noted that in this specification, regarding the "diameter of the cords" among the diameter of the crown belt layer cords, the diameter of the belt layer cords, and the diameter of the carcass cords, when the circumscribed circle of the cross-section perpendicular to the cord extending direction is a perfect circle, it refers to the diameter, and when it is an ellipse or the like, it refers to the equivalent circle diameter (the diameter of the circle assuming the same cross-sectional area).

[0028] 2. Mechanism of Effect Expression in the Tire of the Present Invention

[0029] Regarding the mechanism of the above-described effect expression in the tire of the present invention, the following can be considered.

[0030] (1) Crown Belt Layer

[0031] The crown belt layer can be one layer or two layers. Additionally, the crown belt layer can be formed across the entire width of the tread. Alternatively, it can be formed only at both ends of the tread. It is preferable to use a combination of a crown belt layer formed across the entire width of the tread and a crown belt layer formed at both ends in the width direction of the tread.

[0032] In the tire of the present invention, the crown belt layer cord uses a cord containing PET fibers (PET cord).

[0033] The crown belt layer cord can be composed of fibers. As the fibers constituting the crown belt layer 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 fibers recycled from used products or waste (recycled PET) and fibers synthesized from biomass (biomass PET). Additionally, the crown belt layer cord can also be a mixed cord combining PET fibers and other fibers (such as aramid fibers).

[0034] As described above, the PET cord has higher rigidity than the nylon 66 cord. Therefore, by using the PET cord in the crown belt layer cord, compared with the case of using the nylon 66 cord, the cord thickness (the diameter of the crown belt layer cord) can be reduced, and the cord thickness (the thickness of the crown belt layer) can be reduced. As a result, the cord weight (the weight of the crown belt layer) can be reduced, the tire weight can be reduced, and LRR can be achieved.

[0035] (2) Carcass

[0036] However, as described above, the PET cord has poor compression fatigue resistance compared with the nylon 66 cord. Therefore, there is a possibility of reducing the high-speed durability of the tire.

[0037] Therefore, in the tire of the present invention, first, a carcass formed using a carcass cord with a total fineness exceeding 1200 dtex is used as the carcass.

[0038] By forming the carcass using a relatively thick carcass cord with a total fineness exceeding 1200 dtex, the lateral spring constant can be increased, the degree of deflection generated in the sidewall during driving can be changed (reduced), and the strength of the tire can be ensured. Therefore, it is considered that an improvement in handling stability and an improvement in high-speed durability can be achieved. It should be noted that the total fineness of the carcass cord is preferably 1500 dtex or more, more preferably 2000 dtex or more. As the upper limit, for example, it is preferably 5000 dtex or less, more preferably 4500 dtex or less.

[0039] It should be noted that the total fineness of the above-mentioned carcass cord can be measured according to the method specified in JIS L1017:2002.

[0040] The carcass cord is formed by twisting more than 1 yarn, and preferably by twisting 2 yarns. In the case of twisting 2 yarns, the fineness of each yarn is preferably 1200 dtex or more, and preferably 2500 dtex or less.

[0041] The carcass cord may be composed of fibers. As the fibers constituting the carcass cord, conventionally known fibers can be used, 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, and aromatic polyamide fibers. The fibers constituting the carcass cord may be fibers recycled from used products or waste products (recycled materials), or may be fibers synthesized from biomass (biomass materials).

[0042] Moreover, the carcass may be 1 layer or 2 layers, and preferably 1 layer. By forming a carcass having a 1-layer structure, it is considered that the weight reduction and LRR of the tire can be further achieved as compared with the case of using a 2-layer structure carcass.

[0043] In addition, by forming such a carcass portion, the axial bending rigidity can be sufficiently reduced, and when there is an outer camber angle during turning, the sidewall portion can be sufficiently bent, and the tread can contact the ground more, so it is considered that the handling stability can be improved.

[0044] (3) Tread

[0045] Next, in the tire of the present invention, by using a rubber composition containing more than 20 parts by mass of an isoprene rubber in 100 parts by mass of the rubber component, the tread is formed to have a rubber hardness (Shore hardness) Hs exceeding 70 pt, and the LRR due to the weight reduction of the tire and the high-speed durability are also achieved. It should be noted that the tread may be 1 layer, 2 layers, or 3 layers or more. In the case where the tread is 2 layers or more, it is preferable that the layer on the ground contact side (running surface layer) uses a rubber composition containing more than 20 parts by mass of an isoprene rubber in 100 parts by mass of the rubber component, and the tread is formed with a rubber hardness (Shore hardness) Hs exceeding 70 pt.

[0046] By containing more than 20 parts by mass of an 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 formed, so it is considered that LRR can be achieved. In addition, since the reduction in the rigidity (modulus) of the PET cord caused by the temperature rise of the tread can be suppressed, it is considered that the 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 an upper limit, for example, it is preferably 70 parts by mass or less, more preferably 60 parts by mass or less.

[0047] At this time, if the rubber hardness (Shore hardness) Hs of the tread is small and soft, the amount of deformation of the tread during high-speed driving increases, and the compression applied to the belt layer increases. There is a possibility that the high-speed durability deteriorates due to compression fatigue. Therefore, in the present invention, the rubber hardness (Shore hardness) Hs of the tread exceeds 70 pt.

[0048] Thus, since sufficient rigidity can be ensured and the tread deformation during high-speed driving can be suppressed, it is considered that the compression fatigue applied to the belt layer can be reduced, and an improvement in high-speed durability can be achieved. In addition, 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. Therefore, 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 further preferably more than 75 pt. As an upper limit, for example, it is preferably 85 pt or less, and more preferably 80 pt or less.

[0049] It should be noted that the above rubber hardness (Shore hardness) Hs can be measured using a Type A durometer according to the method specified in JIS K6253-3:2012.

[0050] (4) Bar + Ber + Car + Trg

[0051] In the present invention, the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the belt layer cord, the diameter Ber (mm) of the belt ply cord, the diameter Car (mm) of the carcass cord, and the thickness Trg (mm) of the tread is controlled to be less than 20. Thus, the various effects brought about by the use of the above PET cord, the structure of the carcass, and the characteristics of the tread rubber composition are synergistically exerted, and it is considered that an improvement in the comprehensive performance of low fuel consumption and high-speed durability can be achieved. It is preferably 18 or less, and more preferably 15 or less. As a lower limit, for example, it is preferably 8 or more.

[0052] [2] Preferred embodiments

[0053] By adopting the following methods, greater effects can be obtained.

[0054] 1. Belt layer cord

[0055] In the present invention, as described above, a PET cord is used as the belt layer cord, and a PET cord containing sustainable PET fibers is preferably used. Sustainable PET fibers are fibers containing sustainable materials such as recycled PET and bio-based PET. It should be noted that in this specification, among specific materials (such as PET), materials obtained by recycling used products or waste materials, or materials obtained from biomass as raw materials are referred to as sustainable materials (such as sustainable PET).

[0056] It should be noted that for the lightweight of the tire, the diameter of the cap ply cord (cord diameter) is preferably small, preferably 0.2 mm or more and 0.9 mm or less, more preferably 0.3 mm or more and 0.7 mm or less. In addition, the total fineness of the cap ply cord is preferably 1000 dtex or more, more preferably 1500 dtex or more, and further preferably 2000 dtex or more. In addition, the total fineness of the cap ply cord is preferably 5000 dtex or less, more preferably 4500 dtex or less, and further preferably 4000 dtex or less.

[0057] 2. Belt layer

[0058] The belt layer can be 1 layer, 2 layers or 3 layers or more.

[0059] As the belt layer cord constituting the belt layer, steel cord is preferred. From the aspect of the lightweight of the tire, cord composed of multiple filaments is preferred, and it can also be a strand twisted by multiple filaments. The number of filaments constituting the cord is preferably 1 or more and 8 or less, more preferably 1 or more and 4 or less. It should be noted that as the lower limit, for example, 2 or more is preferably used. In the case of the belt layer cord with the number of filaments being 1 or more and 4 or less, the twisting method can be single twist (for example, 1×2 structure, etc.) or layer twist (for example, 2+2 structure, etc.), etc. In addition, it can also be untwisted (no twist). As the material of the filaments constituting the belt layer cord, metal is preferred, and iron is more preferred. The cross-section of the filaments constituting the belt layer cord can be circular or elliptical, preferably circular, and can be corrugated or treated by plating. In addition, for the lightweight of the tire, the diameter of the belt layer cord (cord diameter) is preferably small, preferably 0.2 mm or more and 0.9 mm or less, more preferably 0.3 mm or more and 0.7 mm or less.

[0060] 3. Tire weight and maximum load capacity

[0061] 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, further preferably less than 0.012, and particularly preferably less than 0.009. As the lower limit, for example, 0.008 or more is preferably used.

[0062] The tire weight can be reduced, for example, by reducing the fineness of various cords (cap ply cord, belt layer cord, carcass cord) constituting the tire components, thinning the thickness of the tread or sidewall, or reducing the density of the rubber composition used for them.

[0063] Thus, a tire with a smaller tire weight compared to the maximum load-bearing capacity of the tire has a relatively thinner rubber thickness, so it can fully suppress the overall temperature rise of the tire, reduce the deformation amount, and can further improve the durability of the tire during driving. It is considered that it can take into account the advantages of LRR improvement and high-speed durability brought by lightweight. It should be noted that in the above text, "tire weight (kg)" refers to the weight of the tire alone without including the weight of the rim.

[0064] Moreover, regarding the "maximum load-bearing capacity (kg)", when the tire cross-sectional width measured in the normal state is set as Wt (mm), the tire cross-sectional height is set as Ht (mm), and the tire outer diameter is set as Dt (mm), it can be obtained as WL through the following formula. In the following formula, V is the hypothetical volume of the tire (mm 3 ). Here, regarding the tire cross-sectional width Wt, in the normal state, when there are patterns or characters on the tire sidewall, it is the maximum width between the outer surfaces of the sidewalls excluding them. And the tire cross-sectional height Ht is half of the difference between the outer diameter of the tire and the nominal diameter of the rim.

[0065] V = {(Dt / 2) 2 - (Dt / 2 - Ht) 2} × π × Wt

[0066] WL = 0.000011 × V + 175

[0067] In the above description, the "normal state" means that the tire is installed on a normal rim, filled with normal internal pressure, and in a load-free state. It should be noted that the "normal internal pressure" refers to the air pressure specified for each tire by each standard in the standard system including the standard on which the tire is based. If it is JATMA (Japan Automobile Tire Association), it refers to the "maximum air pressure". If it is ETRTO (The European Tyre and Rim Technical Organisation), it refers to the "INFLATION PRESSURE (inflation pressure)". If it is TRA (The Tire and Rim Association, Inc.), it refers to the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". Similar to the normal rim, refer to it in the order of JATMA, ETRTO, and TRA. If there is a applicable size during the reference, follow that standard. In the case of a tire not specified in the standard, it refers to the normal internal pressure (but above 250 KPa) of other tire sizes (specified in the standard) for which the above normal rim is recorded as the standard rim. It should be noted that in the case where there are multiple normal internal pressures above 250 KPa, it refers to the minimum value among them.

[0068] It should be noted that a "regular rim" refers to the rim specified for each tire in a standard system including the standards on which the tire is based. For example, in the case of JATMA, it refers to the standard rim in the applicable sizes recorded in the "JATMA YEAR BOOK"; in the case of ETRTO, it refers to the "Measuring Rim" recorded in the "STANDARDS MANUAL"; in the case of TRA, it refers to the "Design Rim" recorded in the "YEAR BOOK". References are made in the order of JATMA, ETRTO, and TRA. When there are applicable sizes, the standard is followed. Additionally, in the case of a tire not specified in the standard, it refers to a rim that can assemble the tire and maintain the internal pressure, that is, a rim that does not leak air between the rim / tire, and among such rims, the one with the smallest rim diameter and then the narrowest rim width.

[0069] 4. Material of carcass cords

[0070] The material of the carcass cords is not particularly limited. 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 bio-based PET. The PET cord has higher rigidity than the nylon 66 cord. Therefore, by using the PET cord in the carcass cords, the high-speed durability can be improved. Additionally, when comparing the PET cord with the nylon 66 cord having the same binding force, the cord diameter becomes smaller. Therefore, by using the PET cord, the tire weight can be reduced, and the LRR effect brought by lightweight can be achieved.

[0071] 5. Diameter of carcass cords Car

[0072] For the lightweight of the tire, the diameter of the carcass cords (cord diameter) is preferably small, 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.

[0073] 6. Thickness of tread Trg

[0074] The thickness of the tread is preferably 4 mm or more, and more preferably 6 mm or more. Thereby, the compression on the belt layer can be reduced, so the compression fatigue resistance can be improved, and the high-speed durability can be improved. It should be noted that if the tread is too thick, the tire weight increases, and the LRR effect brought by the lightweight of the tire components other than the tread is eliminated. Additionally, sometimes the rigidity of the tire decreases and the handling stability tends to deteriorate. Therefore, as the upper limit, it is preferably 20 mm or less, more preferably 15 mm or less, and further preferably 10 mm or less.

[0075] The thickness of the tread refers to the thickness of the tread on the tire equatorial plane in the radial cross-section of the tire. In the case where the tread is formed of a single rubber composition, it is the thickness of the rubber composition. In the case where it is formed of a laminated structure of two or more rubber compositions, it refers to the total thickness of these layers. In the cross-section cut out from the tire in the radial direction, it is measured with the bead portion in a state consistent with the normal rim width.

[0076] [3] Embodiment

[0077] Hereinafter, the present invention will be specifically described based on the embodiment.

[0078] 1. Tire of the present embodiment

[0079] Figure 1 is a schematic cross-sectional view showing the structure of the tire of the present embodiment. Figure 1 In, the up-down direction is the radial direction of the tire, the left-right direction is the rotational axis direction of the tire, and the direction perpendicular to the paper surface is the circumferential direction of the tire. It should be noted that Figure 1 in, the dotted line CL represents the tire equatorial plane. It should be noted that the shape of this tire is symmetric with respect to the equatorial plane except for the tread pattern, and therefore Figure 1 shows 1 / 4 of the entire tire.

[0080] As Figure 1 shown, the tire 1 includes a tread 2, a pair of sidewalls 3, a pair of chafing parts 4, a pair of beads 5, an inner liner 6, a carcass 7, a belt layer 8, a pair of fillers 9, and a cap ply 10. The carcass 7, the belt layer 8, the cap ply 10, and the tread 2 are arranged from the inner side to the outer side in the tire radial direction.

[0081] With such a configuration, as described above, as the cap ply cord, a cord obtained by twisting one yarn containing PET fiber is used, the tread and the carcass are appropriately formed, and further, by appropriately controlling the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the cap ply cord, the diameter Ber (mm) of the belt layer cord, the diameter Car (mm) of the carcass cord, and the thickness Trg (mm) of the tread, it is possible to improve the comprehensive performance of low fuel consumption and high-speed durability.

[0082] 2. Rubber composition for tread

[0083] In the present 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 anti-aging agent.

[0084] (1) Compounding materials

[0085] (a) Rubber component

[0086] As the rubber component, isoprene rubbers such as natural rubber (NR) can be used alone, or a combination of an isoprene rubber and a diene rubber other than an isoprene rubber can be used. As the diene rubber other than an isoprene rubber, for example, diene rubbers such as styrene-butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), chloroprene rubber (CR), and butyl rubber (IIR) can be used, and two types (NR and SBR or NR and BR) can be used in combination, or three types (NR, SBR, and BR) can be used in combination.

[0087] (①) Isoprene rubber

[0088] As the isoprene rubber, natural rubber (NR), and isoprene rubbers other than NR (modified natural rubber (modified NR), modified natural rubber (modified NR), synthetic polyisoprene (isoprene rubber (IR), modified isoprene rubber (modified IR)), etc.) such as synthetic polyisoprene rubbers can be used.

[0089] As NR, for example, NR commonly used in the tire industry such as SVR-L, SIR20, RSS#3, and TSR20 can be used. NR has excellent strength compared to other rubbers.

[0090] The content of NR in 100 parts by mass of the rubber component exceeds 20 parts by mass, preferably 30 parts by mass or more, more preferably 40 parts by mass or more. As the upper limit, it is preferably 70 parts by mass or less, more preferably 60 parts by mass or less.

[0091] As the isoprene rubber other than NR, isoprene rubber (IR), modified NR, modified NR, modified IR, etc. can be cited. As IR, there is no particular limitation, and for example, IR2200 manufactured by Zeon Corporation can be used, which is commonly used in the tire industry. As modified NR, deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), etc. can be cited. As modified NR, epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), grafted natural rubber, etc. can be cited. As modified IR, epoxidized isoprene rubber, hydrogenated isoprene rubber, grafted isoprene rubber, etc. can be cited. They can be used alone or in combination of two or more.

[0092] As the upper limit of the content of the isoprene rubber in 100 parts by mass of the rubber component, it is preferably 100 parts by mass or less, more preferably 90 parts by mass or less, 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.

[0093] (②) SBR

[0094] The weight-average molecular weight of the SBR is, for example, more than 100,000 and less than 2,000,000. The styrene content of the 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 the 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. It should be noted that the structural identification (determination of styrene content and vinyl content) of the SBR can be carried out, for example, using a device of the JNM-ECA series manufactured by JEOL Ltd.

[0095] There is no particular limitation on the SBR, and for example, emulsion-polymerized styrene-butadiene rubber (E-SBR), solution-polymerized styrene-butadiene rubber (S-SBR), etc. can be used. The SBR can be either unmodified SBR or modified SBR. In addition, hydrogenated SBR obtained by hydrogenating the butadiene part in the SBR can be used. The hydrogenated SBR can also be obtained by subsequently hydrogenating the BR part in the SBR, or the same structure can be obtained by copolymerizing styrene, ethylene, and butadiene.

[0096] As the modified SBR, an SBR having a functional group that interacts with a filler such as silica is preferred. Examples include a terminal-modified SBR (a terminal-modified SBR having the above functional group at the terminal) obtained by modifying at least one terminal of the SBR with a compound (modifying agent) having the above functional group; a main-chain modified SBR having the above functional group in the main chain; a main-chain and terminal modified SBR having the above functional group in the main chain and at the terminal (for example, a main-chain and terminal modified SBR having the above functional group in the main chain and modifying at least one terminal with the above modifying agent); a terminal-modified SBR modified (coupled) with a polyfunctional compound having two or more epoxy groups in the molecule and introducing a hydroxyl group, an epoxy group, etc.

[0097] 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 thioether group, a disulfide group, a sulfonyl group, a sulfinyl group, a thiocarbonyl group, an ammonium group, an imide group, a hydrazine 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. It should be noted that these functional groups can have substituents.

[0098] In addition, as the modified SBR, for example, an SBR modified with a compound (modifying agent) represented by the following formula can be used.

[0099] [Chemical formula 1]

[0100]

[0101] It should be noted that 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 can be bonded to form a ring structure together with the nitrogen atom. n represents an integer.

[0102] As the modified SBR modified with the compound (modifier) 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 Japanese Patent Laid-Open No. 2010-111753, etc.) can be used.

[0103] As R 1 , R 2 and R 3 , an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms) is suitable. As R 4 and R 5 , an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms) is suitable. n is preferably 1 to 5, more preferably 2 to 4, and further preferably 3. In addition, when R 4 and R 5 are bonded to form a ring structure together with the nitrogen atom, a 4- to 8-membered ring is preferred. It should be noted that the alkoxy group also includes a cycloalkoxy group (such as cyclohexyloxy) and an aryloxy group (such as phenoxy and benzyloxy).

[0104] Specific examples of the above modifier include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, etc. They can be used alone or in combination of two or more.

[0105] In addition, as the modified SBR, a modified SBR modified with the following compounds (modifiers) can also be used. Examples of the modifiers include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, and 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, and polyepoxidized liquid polybutadiene; epoxy group-containing tertiary amines such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl-o-toluidine, tetraglycidyl-m-xylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-bis(aminomethyl)cyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamoyl chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamoyl chloride, and N,N-diethylcarbamoyl chloride; epoxy group-containing silane compounds such as 1,3-bis(epoxypropylpropyl)-tetramethyldisiloxane and (3-epoxypropylpropyl)-pentamethyldisiloxane; thioether group-containing silane compounds such as (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, and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide; N-substituted aziridine compounds such as aziridine and propyleneimine; alkoxysilanes such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, and 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-tert-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-tert-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; and N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tri-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-trione, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylvinylurea, 1,3-divinylvinylurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-acetone, 1,7-bis(methylethylamino)-4-heptanone, etc. It should be noted that the modification by the above compounds (modifiers) can be carried out by known methods.

[0106] As the SBR, for example, SBR manufactured and sold by Sumitomo Chemical Co., Ltd., ENEOS Materials Co., Ltd., Asahi Kasei Corporation, Zeon Corporation, etc. can be used. It should be noted that the SBR can be used alone or in combination of two or more.

[0107] 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 further preferably 40 parts by mass or more. As the upper limit, it is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and further preferably 55 parts by mass or less.

[0108] (③) BR

[0109] 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. It should be noted that the cis content can be measured by infrared absorption spectrometry.

[0110] 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.

[0111] [Chemical formula 2]

[0112]

[0113] It should be noted that in the formula, R 1 , R 2 and R 3 are the same or different and represent an alkyl group, an alkoxy group, a siloxy 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 can be bonded to form a ring structure together with the nitrogen atom. n represents an integer.

[0114] As the modified BR modified with the compound (modifying agent) represented by the above formula, BR obtained by modifying the polymerization terminal (active terminal) with the compound represented by the above formula can be cited.

[0115] As R 1 , R 2 and R 3 , an alkoxy group (preferably an alkoxy group having 1 to 8 carbon atoms, more preferably 1 to 4 carbon atoms) is suitable. As R 4 and R 5 , an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms) is suitable. n is preferably 1 to 5, more preferably 2 to 4, and further preferably 3. In addition, when R 4 and R 5 are bonded to form a ring structure together with the nitrogen atom, a 4- to 8-membered ring is preferred. It should be noted that the alkoxy group also includes a cycloalkoxy group (such as cyclohexyloxy) and an aryloxy group (such as phenoxy and benzyloxy).

[0116] As specific examples of the above-mentioned modifiers, 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, 3-diethylaminopropyltriethoxysilane, etc. can be cited. They can be used alone or in combination of two or more kinds.

[0117] In addition, as the modified BR, a modified BR obtained by modifying 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, glycerol triglycidyl ether, trimethylolethane triglycidyl ether, and trimethylolpropane triglycidyl ether; polyglycidyl ethers of aromatic compounds having two or more phenol groups such as diglycidylated bisphenol A; polyepoxides such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxidized liquid polybutadiene; tertiary amines containing epoxy groups such as 4,4'-diglycidyl-diphenylmethanamine and 4,4'-diglycidyl-dibenzylmethanamine; diglycidylamino compounds such as diglycidylaniline, N,N'-diglycidyl-4-glycidyloxyaniline, diglycidyl-o-toluidine, tetraglycidyl-m-xylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-bis(aminomethyl)cyclohexane; amino group-containing acid chlorides such as bis-(1-methylpropyl)carbamoyl chloride, 4-morpholinecarbonyl chloride, 1-pyrrolidinecarbonyl chloride, N,N-dimethylcarbamoyl chloride, and N,N-diethylcarbamoyl chloride; silane compounds containing epoxy groups such as 1,3-bis-(glycidoxypropyl)-tetramethyldisiloxane and (3-glycidoxypropyl)-pentamethyldisiloxane; thioether group-containing silane compounds such as (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, and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl]sulfide; N-substituted aziridine compounds such as aziridine and propyleneimine; alkoxysilanes such as methyltriethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)-3-aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, and N,N-bis(trimethylsilyl)aminoethyltriethoxysilane;(Thio)benzophenone compounds having amino groups and / or substituted amino groups such as 4-N,N-dimethylaminobenzophenone, 4-N,N-di-tert-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 amino groups and / or substituted amino groups 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-tert-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; and N,N-bis-(2,3-epoxypropoxy)-aniline, 4,4-methylene-bis-(N,N-glycidylaniline), tri-(2,3-epoxypropyl)-1,3,5-triazine-2,4,6-trione, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylvinylurea, 1,3-divinylvinylurea, 1,3-diethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-acetone, 1,7-bis(methylethylamino)-4-heptanone, etc. It should be noted that the modification by the above compounds (modifiers) can be carried out by known methods. It should be noted that these modified BRs can be used alone or in combination of two or more.

[0118] As the BR, products of, for example, Ube Industries, Ltd., ENEOS Materials Co., Ltd., Asahi Kasei Corporation, Nippon Zeon Co., Ltd. etc. can be used.

[0119] 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.

[0120] (④) Other rubber components

[0121] In the rubber composition, as other rubber components, rubber (polymers) such as nitrile rubber (NBR) that are commonly used in the manufacture of tires may be included as needed.

[0122] It should be noted that the raw materials (monomers) of the above-mentioned synthetic rubbers such as IR, SBR, and BR can be derived from underground resources such as petroleum and natural gas, or can be recycled from rubber products such as tires or non-rubber products such as polystyrene.

[0123] The monomers obtained by recycling (recycled monomers) are not particularly limited, and examples include recycled polyisoprene, recycled butadiene, recycled aromatic vinyl monomers, etc. As the above-mentioned butadiene, 1,2-butadiene and 1,3-butadiene can be cited. As the above-mentioned aromatic vinyl monomer, it is not particularly limited, and styrene etc. can be cited. Among them, recycled polyisoprene (recycled isoprene), butadiene (recycled butadiene) and / or recycled styrene (recycled styrene) from recycling are preferably used as raw materials.

[0124] The method for manufacturing recycled monomers is not particularly limited, and examples include synthesis from recycled naphtha obtained by decomposing rubber products such as tires. In addition, the method for manufacturing recycled naphtha is not particularly limited. For example, rubber products such as tires can be decomposed under high temperature and high pressure, or can be decomposed by microwaves, or can be extracted after mechanical pulverization.

[0125] In addition, the raw materials (monomers) of synthetic rubbers such as IR, SBR, and BR can be derived from biomass. In this specification, biomass refers to substances from natural resources such as plants. Biomass is not particularly limited, and examples include agricultural, forestry, and fishery products, sugars, woods, plant residues after obtaining useful components, plant-derived ethanol, biomass naphtha, etc.

[0126] The monomers derived from biomass (biomass monomers) are not particularly limited, and examples include butadiene derived from biomass, aromatic vinyl monomers derived from biomass, etc. As the above-mentioned butadiene, 1,2-butadiene and 1,3-butadiene can be cited. As the above-mentioned aromatic vinyl monomer, it is not particularly limited, and styrene etc. can be cited. In addition, the method for manufacturing biomass monomers is not particularly limited, and examples include methods based on biological and / or chemical and / or physical conversion of animals and plants. As biological conversion, fermentation using microorganisms is representative, and as chemical and physical conversion, conversion using catalysts, conversion using high heat, conversion using high pressure, conversion using electromagnetic waves, conversion using critical liquids, and combinations thereof can be cited.

[0127] As a polymer synthesized from biomass monomer components (biomass polymer), there is no particular limitation, and examples include polybutadiene rubber synthesized from butadiene derived from biomass, and aromatic vinyl monomer / butadiene copolymers synthesized from butadiene derived from biomass and / or aromatic vinyl monomers derived from biomass. As the above-mentioned aromatic vinyl monomer / butadiene copolymer, for example, styrene-butadiene rubber synthesized from butadiene derived from biomass and / or styrene derived from biomass can be mentioned.

[0128] Whether the raw material of the polymer is derived from biomass can be judged by pMC (percent Modern Carbon) measured according to ASTM D 6866-10.

[0129] pMC refers to the 14 ratio of the C concentration of the sample to the 14 C concentration of the modern standard reference, and it is a value used as an index to represent the biomass ratio of a compound. The meaning of this value is as follows.

[0130] In 1 mole (6.02×10 23 ), there are approximately one trillionth of ordinary carbon atoms, that is, about 6.02×10 11 atoms of 14 C. 14 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 them to decay. Therefore, after carbon dioxide in the atmosphere is taken in and fixed by plants, etc., it is considered that in fossil fuels such as coal, oil, and natural gas that have passed more than 226,000 years, all the 14 C elements contained in these substances at the time of fixation have decayed. Therefore, in the present of the 21st century, fossil fuels such as coal, oil, and natural gas do not contain 14 C elements at all. Therefore, chemical substances produced from these fossil fuels also do not contain 14 C elements at all.

[0131] On the other hand, cosmic rays undergo nuclear reactions in the atmosphere and continuously generate 14 C, which is in balance with the decrease caused by radiation decay, and the amount of 14 C in the earth's atmospheric environment is a certain amount. Therefore, the -12 C concentration of substances derived from biomass resources that are recycled in the current environment is about 1×10mol% with respect to the overall C atoms as described above. Therefore, by using the difference between these values, the biomass ratio in a certain compound can be calculated.

[0132] This14 The measurement of C is generally carried out as follows. Using accelerator mass spectrometry based on a tandem accelerator, 13 the concentration of 13 C / 12 C), 14 the concentration of 14 C / 12 C) is measured. In the measurement, the concentration of 14 C in the cyclic carbon in nature in 1950 is used as 14 the reference for the concentration of 14 C, that is, the modern standard reference. As a specific reference material, the oxalic acid standard provided by NIST (National Institute of Standards and Technology) is used. The specific radioactivity of carbon in this oxalic acid (the radioactivity intensity of 13 C per 1 g of carbon) is separated into each carbon isotope, corrected to a certain value for 14 C, and decay correction is carried out from 1950 AD to the measurement date, and the obtained value is used as the value of the standard

[0133] concentration of 14 C (100%). The ratio of this value to the value of the actually measured sample becomes the pMC value.

[0134] Therefore, if rubber is made from a material that is 100% derived from biomass (natural system), although there are regional differences, etc., it generally does not reach 100 under normal conditions at present, so it shows a value of about 110 pMC. On the other hand, for chemical substances derived from fossil fuels such as petroleum, when measuring the

[0135] (b) Blending materials other than rubber components

[0136] (①) Filler

[0137] The rubber composition preferably contains silica or carbon black as a reinforcing agent, but other fillers such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, etc. can also be contained as needed. It should be noted that when using silica, it is preferably used in combination with a silane coupling agent.

[0138] The compounding amount of the filler is preferably 60 parts by mass or more, more preferably 80 parts by mass or more, and further preferably 110 parts by mass or more with respect to 100 parts by mass of the rubber component. On the other hand, from the aspect of dispersibility in the rubber composition, it is preferably 150 parts by mass or less, more preferably 140 parts by mass or less.

[0139] (i) silica

[0140] Silica has OH groups on its surface. Therefore, by containing a large amount, hydrogen bonds are generated between the silica surfaces, and it also interacts with the rubber component. Therefore, when driving, it is possible to easily generate and transmit forces inside the rubber, and it is possible to easily transmit the forces generated during turning, ensuring excellent handling stability. 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 enhanced. It should be noted that the content of silica is preferably 50 parts by mass or more, more preferably 70 parts by mass or more, and further preferably 90 parts by mass or more with respect to 100 parts by mass of the rubber component. As the upper limit, it is preferably 150 parts by mass or less, more preferably 130 parts by mass or less.

[0141] From the aspect of obtaining good durability performance, the BET specific surface area of silica is preferably more than 100 m 2 / g, more preferably more than 130 m 2 / g. On the other hand, it is preferably less than 250 m 2 / g, more preferably less than 200 m 2 / g. It should be noted that the above BET specific surface area is the N2SA value measured by the BET method in accordance with ASTM D3037-93.

[0142] There is no particular limitation on the silica, and for example, silica prepared by the dry method (anhydrous silica), silica prepared by the wet method (hydrous silica), etc., which are commonly used 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.

[0143] There is no particular limitation on the raw material of silica. For example, it can be a raw material from a mineral source such as quartz, or a raw material from a biological source such as rice husk (for example, silica using biomass materials such as rice husk as the raw material), and silica recycled from products containing silica can also be used. Among them, due to the large number of silanol groups, hydrous silica prepared by the wet method is preferred. Among them, sustainable silica (silica using biomass materials as the raw material or silica recycled from products containing silica) is preferred.

[0144] Silica made from biomass materials can be obtained, for example, as follows: Silicate is extracted from rice husk ash obtained by burning rice husks using a sodium hydroxide solution, and the precipitation of silica produced by reacting with sulfuric acid is filtered, washed with water, dried, and pulverized in the same manner as existing wet silica using this silicate, whereby it can be obtained.

[0145] Silica recycled from products containing silica can use, for example, silica recovered from products containing silica such as semiconductor and other electronic components, tires, desiccants, filter materials such as diatomaceous earth, etc. In addition, as the recovery method, there is no particular limitation, and examples include thermal decomposition, decomposition using electromagnetic waves, etc. Among them, silica recovered from semiconductor and other electronic components or tires is preferred.

[0146] When silica crystallizes, it is insoluble in water and the silicic acid as its component cannot be utilized. By controlling the combustion temperature and combustion time, crystallization of silica in rice husk ash can be suppressed (refer to Japanese Patent Laid-Open No. 2009-2594, Akita Prefectural University Online Journal B / 2019, vol. 6, p. 216-222, etc.).

[0147] Amorphous silica extracted from rice husks can use commercially available amorphous silica such as that from Wilmar Corporation.

[0148] It should be noted that these silicas can be used alone or in combination of two or more. It should be noted that from the aspect of environmental protection (sustainability), it is suitable to use biomass silica and recycled silica.

[0149] (ii) Silane coupling agent

[0150] When using silica, in order to improve the dispersibility of silica and at the same time achieve improvements in mechanical properties, moldability, etc. through reaction with silica, it is preferable to use a silane coupling agent in combination.

[0151] As the silane coupling agent, there is no particular limitation, and examples thereof include 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 and other sulfur-containing compounds, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, NXT, NXT-Z manufactured by Momentive and other mercapto compounds, vinyltriethoxysilane, vinyltrimethoxysilane and other vinyl compounds, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane and other amino compounds, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane and other glycidoxy compounds, 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane and other nitro compounds, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane and other chlorine compounds. Among them, a silane coupling agent having a thiocarbonyl group such as the above-mentioned NXT is preferred. They can be used alone or in combination of two or more.

[0152] As the silane coupling agent, 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.

[0153] The content of the silane coupling agent is preferably more than 2 parts by mass, more preferably 3 parts by mass or more, and further 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 further preferably 9 parts by mass or less.

[0154] (iii) Carbon black

[0155] Carbon black is preferably used for the purpose of improving the crack growth resistance, durability, ultraviolet degradation resistance etc. of the tire.

[0156] From the aspect of the reinforcement of 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 further preferably 60 m 2 / g or more. On the other hand, from the aspect of heat generation, it is preferably 250 m 2 / g or less, more preferably 150 m 2 / g or less, and further preferably 120 m 2 / g or less. It should be noted that the nitrogen adsorption specific surface area of carbon black is measured according to ASTM D4820-93.

[0157] From the aspect of the rigidity of rubber, the dibutyl phthalate (DBP) absorption 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 aspect of the followability of rubber deformation, it is preferably 250 ml / 100 g or less, more preferably 150 ml / 100 g or less. It should be noted that the DBP absorption of carbon black is measured according to ASTM D2414-93.

[0158] There is no particular limitation on the carbon black, and examples thereof include furnace black (such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF); acetylene black; thermal carbon black (such as FT and MT); channel carbon black (such as EPC, MPC, and CC), etc. In addition, as the part number, examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, N762, etc. They can be used alone or in combination of two or more.

[0159] In addition to mineral oil, the raw material of carbon black can also be biomass materials such as lignin and vegetable oil, or pyrolysis oil (recycled carbon black) obtained by pyrolyzing rubber products containing carbon black such as waste tires. As carbon black, sustainable carbon black (carbon black with biomass materials as raw materials or recycled carbon black) is preferably used.

[0160] In addition, the manufacturing method of carbon black can be manufactured by combustion such as the furnace method, or can be manufactured by hydrothermal carbonization (HTC), or can also be manufactured by pyrolysis of methane based on the thermal carbon black method, etc.

[0161] 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. They can be used alone or in combination of two or more.

[0162] 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. As the upper limit, it is preferably 30 parts by mass or less, more preferably 25 parts by mass or less.

[0163] (iv) Rubber powder

[0164] Vulcanized rubber particles are particles made of vulcanized rubber. Specifically, rubber powder specified in JIS K 6316:2017 can be used, etc. From the aspects of environmental consideration and cost, recycled rubber powder made from crushed waste tires, etc. is preferred. They can be used alone or in combination of two or more.

[0165] (v) Other fillers

[0166] In addition to the above carbon black and silica, the rubber composition may further contain fillers commonly used in the tire industry such as graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, magnesium sulfate, etc. Relative to 100 parts by mass of the rubber component, when containing them, the content is, for example, more than 0.1 part by mass and less than 150 parts by mass.

[0167] (②) Softener component

[0168] In the rubber composition, from the aspect of imparting plasticity to the rubber component during mixing and appropriately dispersing the powder materials, it is preferably to use a softener component as needed. It should be noted that the softener component here refers to the concept including both softeners that are liquid at 25°C and softeners that are solid at 25°C.

[0169] Examples of softeners can include resin components, oils, liquid polymers, ester plasticizers, etc. These softeners can be derived from mineral resources such as petroleum or natural gas, can also be derived from biomass, and can also be derived from naphtha recycled from rubber products or non-rubber products. In addition, low-molecular-weight hydrocarbon components obtained by pyrolyzing and extracting used tires or products containing various components can also be used as softeners, among which softeners derived from biomass or from recycling are preferably used as sustainable softeners.

[0170] It should be noted that these softeners can be used alone or in combination of two or more. As the content of the plasticizer component relative to 100 parts by mass of the rubber component, it is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and further preferably 7 parts by mass or more. As the upper limit, it is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and further preferably 15 parts by mass or less. It should be noted that the content of the plasticizer component also includes the amount of oil contained in rubber (oil-extended rubber), etc.

[0171] (i) Oil

[0172] Examples of the oil include mineral oil, vegetable oil, animal oil, etc. In addition, from the aspect of life cycle assessment, oil refined from waste oil used in a rubber mixer or an engine, or waste cooking oil used in a cooking shop can also be used.

[0173] (i-1) Mineral oil

[0174] In this specification, 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, aromatic oil, etc.

[0175] 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), etc.

[0176] In addition, for environmental countermeasures, oil with a low content of polycyclic aromatic compound (PCA) can also be used. Examples of the oil with a low PCA content include MES, TDAE, heavy naphthenic oil, etc.

[0177] Examples of commercially available mineral oil include oils such as paraffinic, aromatic, and naphthenic oils. Products of Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Corporation, OLISOY, H&R, Toyokuni Oil Co., Ltd., Showa Shell Sekiyu KK, Fujikosan Co., Ltd., etc. can be used. They can be used alone or in combination of two or more.

[0178] (i-2) Vegetable oil

[0179] Examples of vegetable oils include, for example, linseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice oil, tall oil, sesame oil, fragrant oil, castor oil, tung oil, pine oil, pine tar, 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.

[0180] In addition, examples of vegetable oils also include refined oils (such as salad oil) obtained by refining the above-mentioned various oils, transesterified oils after transesterification, solidified oils after hydrogenation, thermally polymerized oils after thermal polymerization, oxidation-polymerized oils after oxidation, waste cooking oils recovered after being used as edible oils, etc. It should be noted that vegetable oils can be liquid or solid at room temperature (25°C). They can be used alone or in combination of two or more.

[0181] As vegetable oils, it is preferred to contain acylglycerols, and more preferably to contain triacylglycerols. It should be noted that acylglycerols refer to compounds in which the hydroxyl groups of glycerol form ester bonds with fatty acids. There is no particular limitation on acylglycerols, which can be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. In addition, acylglycerols can be monomers, dimers, or polymers of trimers or more. It should be noted that acylglycerols of dimers or more can be obtained by thermal polymerization or oxidation polymerization, etc. In addition, acylglycerols can be liquid or solid at room temperature (25°C).

[0182] As a method for confirming whether acylglycerols are contained in the rubber composition, there is no particular limitation, and it can be confirmed by 1 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, 1H-NMR is measured at room temperature. 1 When the signal of tetramethylsilane (TMS) is set to 0.00 ppm, signals around 5.26 ppm, around 4.28 ppm, and around 4.15 ppm are observed. It is speculated that these signals are signals from hydrogen atoms bonded to carbon atoms adjacent to the oxygen atom of the ester group. Therefore, it can be confirmed that acylglycerols are contained. It should be noted that "around" here refers to a range of ±0.10 ppm.

[0183] It should be noted that there is no particular limitation on fatty acids, which can be unsaturated fatty acids or saturated fatty acids. Examples of unsaturated fatty acids include monovalent unsaturated fatty acids such as oleic acid, and polyvalent unsaturated fatty acids such as linoleic acid and linolenic acid. In addition, examples of saturated fatty acids include butyric acid and lauric acid.

[0184] Among them, as the above fatty acids, fatty acids with fewer double bonds, that is, saturated fatty acids or monounsaturated fatty acids, are preferably included, and oleic acid is preferred. As the vegetable oil containing such fatty acids, for example, a vegetable oil containing saturated fatty acids or monounsaturated fatty acids can be used, or a modified vegetable oil such as a transesterified vegetable oil can also be used. In addition, in order to produce a vegetable oil containing such fatty acids, plants can also be improved by variety improvement, genetic recombination, genome editing, etc.

[0185] As the vegetable oil, for example, commercially available vegetable oils such as those produced by Idemitsu Kosan Co., Ltd., Sankyo Yuka Kogyo Co., Ltd., ENEOS Co., Ltd., OLISOY Co., H&R Co., Toyokuni Oil Co., Ltd., Fuji Kogyo Co., Ltd., and Nisshin Oillio Group Co., Ltd. can be used.

[0186] (ii) Liquid rubber

[0187] Liquid rubber refers to a polymer in a liquid state at normal temperature (25 °C), and is a rubber component that can be extracted from vulcanized tires by acetone extraction. Examples of liquid rubber include farnesene-based polymers, liquid diene-based polymers, and their hydrides.

[0188] A farnesene-based polymer refers to a polymer obtained by polymerizing farnesene and has a structural unit based on farnesene. 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) exist in farnesene.

[0189] The farnesene-based polymer can be a homopolymer of farnesene (farnesene homopolymer) or a copolymer of farnesene and a vinyl monomer (farnesene-vinyl monomer copolymer).

[0190] 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), etc.

[0191] The polystyrene-reduced weight average molecular weight (Mw) of the liquid diene-based polymer measured by gel permeation chromatography (GPC) is, for example, more than 1.0×10 3 and less than 2.0×10 5 . Here, the Mw of the liquid diene-based polymer is the polystyrene-reduced value measured by gel permeation chromatography (GPC).

[0192] As the liquid rubber, products of, for example, Kuraray Co., Ltd. and Cray Valley Co., Ltd. can be used.

[0193] (iii) Resin component

[0194] The resin component also functions as an adhesion - imparting component. It can be solid or liquid at normal temperature. As specific resin components, for example, rosin - based resins, styrene - based resins, benzofuran - based resins, terpene - based resins, C5 resins, C9 resins, C5C9 resins, acrylic resins, etc. can be cited, and two or more of them can be used in combination. It should be noted that these resin components can also be given a modified group capable of reacting with silica, etc. as required. 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, relative to 100 parts by mass of the rubber component.

[0195] The rosin - based resin is a resin mainly composed of rosin acid obtained by processing pine resin. This rosin - based resin (rosin) can be classified according to whether it is modified or not, and can be classified into unmodified rosin (unmodified rosin) and rosin modified products (rosin derivatives). As unmodified rosin, tall oil rosin (also known as tall oil rosin), gum rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosins can be cited. Rosin modified products are modified products of unmodified rosin, and rosin esters, unsaturated carboxylic acid - modified rosins, unsaturated carboxylic acid - modified rosin esters, amide compounds of rosin, amine salts of rosin, etc. can be cited.

[0196] The styrene - based resin is a polymer using styrene - based monomers as constituent monomers, and polymers obtained by polymerizing styrene - based monomers as the main component (50 mass% or more) can be cited. Specifically, in addition to homopolymers obtained by homopolymerizing styrene - based monomers (styrene, o - methylstyrene, m - methylstyrene, p - methylstyrene, α - methylstyrene, p - methoxystyrene, p - tert - butylstyrene, p - phenylstyrene, o - chlorostyrene, m - chlorostyrene, p - chlorostyrene, etc.) respectively, and copolymers obtained by copolymerizing two or more styrene - based monomers, copolymers of styrene - based monomers and other monomers capable of copolymerizing with them can also be cited.

[0197] As the above - mentioned other monomers, acrylonitrile - based monomers such as acrylonitrile and methacrylonitrile, unsaturated carboxylic acids such as acrylic acid and 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 or their acid anhydrides such as maleic anhydride; etc. can be exemplified.

[0198] Among benzofuran resins, benzofuran indene resins are preferred. Benzene indene resins are resins containing benzofuran and indene as monomer components constituting the backbone (main chain) of the resin. Examples of monomer components contained in the backbone other than benzofuran and indene include styrene, α-methylstyrene, methylindene, vinyltoluene, and the like.

[0199] 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 refers to the amount of potassium hydroxide required to neutralize acetic acid bonded to the hydroxyl group when 1 g of the resin is acetylated, expressed in milligrams, and is a value measured by potentiometric titration (JIS K 0070: 1992).

[0200] The softening point of the coumarone indene resin is, for example, higher than 30° C. and lower than 160° C. The softening point is a softening point specified in JIS K 6220-1:2001 and measured using a ring and ball softening point measuring apparatus, and is a temperature at which a ball falls.

[0201] Examples of terpene resins include polyterpenes, terpene phenols, and aromatic modified terpene resins. Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrogenated products. Terpene compounds are composed of (C5H8) n The hydrocarbons and their oxygenated derivatives are classified as monoterpenes (C 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32 ) and the like as a basic skeleton, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, alloocimene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinolene, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, γ-terpineol, etc. can be mentioned.

[0202] As polyterpenes, in addition to terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, β-pinene / limonene resin, etc. which are made from the above-mentioned terpene compounds as raw materials, hydrogenated terpene resins obtained by hydrogenating the terpene resins can also be cited. As terpene phenols, resins copolymerized from the above-mentioned terpene compounds and phenolic compounds, and resins obtained by hydrogenating such resins can be cited. Specifically, resins obtained by condensing the above-mentioned terpene compounds, phenolic compounds and formaldehyde can be cited. It should be noted that as phenolic compounds, for example, phenol, bisphenol A, cresol, xylenol, etc. can be cited. As aromatic modified terpene resins, resins obtained by modifying terpene resins with aromatic compounds, and resins obtained by hydrogenating such resins can be cited. It should be noted that as aromatic compounds, as long as they are compounds having an aromatic ring, there is no particular limitation, and for example, phenolic compounds such as phenol, alkylphenol, alkoxyphenol, phenol containing an unsaturated hydrocarbon group, etc.; naphthol compounds such as naphthol, alkylnaphthol, alkoxynaphthol, naphthol containing an unsaturated hydrocarbon group, etc.; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, styrene containing an unsaturated hydrocarbon group, etc.; benzofuran, indene, etc. can be cited.

[0203] "C5 resin" refers to a resin obtained by polymerizing a C5 fraction. As the C5 fraction, for example, petroleum fractions corresponding to 4 to 5 carbon atoms such as cyclopentadiene, pentene, pentadiene, isoprene, etc. can be cited. As C5-based petroleum resins, dicyclopentadiene resin (DCPD resin) is preferably used.

[0204] "C9 resin" refers to a resin obtained by polymerizing a C9 fraction, or a resin obtained by hydrogenating or modifying them. As the C9 fraction, for example, petroleum fractions corresponding to 8 to 10 carbon atoms such as vinyltoluene, alkylstyrene, indene, methylindene, etc. can be cited. As a specific example, for example, benzofuran indene resin, benzofuran resin, indene resin and aromatic vinyl-based resins are preferably used. As aromatic vinyl-based resins, for reasons of economy, easy processing and excellent heat generation properties, α-methylstyrene (AMS resin) or a homopolymer of styrene or a copolymer of α-methylstyrene and styrene is more preferably used, and a copolymer of α-methylstyrene and styrene is even more preferably used. As aromatic vinyl-based resins, for example, aromatic vinyl-based resins commercially available from companies such as KRATON and Eastman Chemical can be used.

[0205] "C5C9 resin" refers to a resin obtained by copolymerizing the above-mentioned C5 fraction and the above-mentioned C9 fraction, or a resin obtained by hydrogenating or modifying them. As the C5 fraction and the C9 fraction, the above-mentioned petroleum fractions can be cited. As C5C9 resins, for example, resins commercially available from Tosoh Corporation, LUHUA Company, etc. can be used.

[0206] The acrylic resin is not particularly limited, and for example, a solvent-free acrylic resin can be used.

[0207] Solvent-free acrylic resins include (meth) acrylic resins (polymers) synthesized by a high-temperature continuous polymerization method (high-temperature continuous bulk polymerization method) (methods described in U.S. Patent No. 4,414,370, Japanese Patent Publication No. 59-6207, Japanese Patent Publication No. 5-58005, Japanese Patent Publication No. 1-313522, U.S. Patent No. 5,010,166, East Asia Synthesis Research Annual Report TREND 2000 No. 3, p. 42-45, etc.) without using a polymerization initiator, a chain transfer agent, an organic solvent, etc. as secondary raw materials as much as possible. It should be noted that (meth) acrylic acid refers to methacrylic acid and acrylic acid.

[0208] Examples of the monomer components constituting the acrylic resin include (meth)acrylic acid, (meth)acrylic acid esters (alkyl esters, aryl esters, arylalkyl esters, etc.), (meth)acrylamide, and (meth)acrylic acid derivatives such as (meth)acrylamide derivatives.

[0209] As monomer components constituting the acrylic resin, aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene may be used together with (meth)acrylic acid or a (meth)acrylic acid derivative.

[0210] The acrylic resin may be a resin composed only of a (meth)acrylic acid component or a resin containing components other than the (meth)acrylic acid component as constituent elements. In addition, the acrylic resin may have a hydroxyl group, a carboxyl group, a silanol group, or the like.

[0211] As the resin component, for example, products of Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Corporation, Rutgers Chemicals, BASF, KRATON, Nippon Paint Chemicals Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Co., Ltd., Arakawa Chemical Industries, Ltd., and Taoka Chemical Industries, Ltd. can be used.

[0212] (③) Wax

[0213] The rubber composition may contain wax. The content of the 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, based on 100 parts by mass of the rubber component.

[0214] As the wax, there is no particular limitation, and any wax commonly used in the tire industry can be suitably used. For example, mineral waxes, waxes of plant origin, etc. can be cited. Mineral waxes refer to waxes derived from mineral resources such as oil and natural gas. Among them, waxes of plant origin are preferred.

[0215] As waxes of plant origin, for example, rice bran wax, carnauba wax, candelilla wax, etc. can be cited. As mineral waxes, for example, paraffin wax, microcrystalline wax, their selected special waxes, etc. can be cited, and paraffin wax is preferred. It should be noted that the wax does not include stearic acid.

[0216] It should be noted that as the wax, for example, waxes commercially available from Ouchi Shinko Chemical Industry Co., Ltd., Nippon Seiro Co., Ltd., Paramelt Corporation, etc. can be used. These waxes can be used alone or in combination of two or more.

[0217] (④)Antioxidant

[0218] 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 relative to 100 parts by mass of the rubber component.

[0219] There is no particular limitation on the antioxidant, and examples thereof include naphthylamine-based antioxidants such as phenyl-α-naphthylamine; diphenylamine-based antioxidants such as octylated diphenylamine, 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; p-phenylenediamine-based antioxidants 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'-dimethylxyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based antioxidants such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based antioxidants such as 2,6-di-tert-butyl-4-methylphenol, styrenated phenol; bisphenol-based, triphenol-based, polyphenol-based antioxidants such as tetrakis[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, etc. Among them, p-phenylenediamine-based antioxidants and quinoline-based antioxidants are preferred, and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and polymers of 2,2,4-trimethyl-1,2-dihydroquinoline are more preferred. They can be used alone or in combination of two or more.

[0220] As commercial products, products of, for example, Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinko Chemical Industry Co., Ltd., Flexis Corporation, etc. can be used.

[0221] (⑤)Processing aids

[0222] The rubber composition may contain a processing aid. Examples of the processing aid include metal salts (compounds in which a hydrogen atom of an acid is replaced by a metal ion), fatty acid amides, amide esters, fatty acid esters, etc. They 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.

[0223] 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. In addition, magnesium, zinc, nickel, molybdenum, etc. can also be used. Among them, alkali metals are preferred.

[0224] Examples of the acid used in the metal salt include fatty acids such as lauric acid, myristic acid, and palmitic acid. In addition, boric acid, carbonic acid, hydrochloric acid, nitric acid, sulfuric acid, etc. can also be used.

[0225] As commercially available products of the processing aid, products of Kishida Chemical Co., Ltd., Kenzo Pharmaceutical Co., Ltd., Struktol Company, Performance Additives Company, etc. can be used.

[0226] The content of the processing aid is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the rubber component. As the upper limit, it is preferably 6 parts by mass or less, more preferably 4 parts by mass or less.

[0227] (⑥) Lubricant (stearic acid)

[0228] The rubber composition may contain a lubricant. As the lubricant, a lubricant based on a fatty acid derivative such as stearic acid is preferably used. As stearic acid, conventionally known stearic acid can be used. Specifically, products of Nippon Oil Corporation, NOF Corporation, Kao Corporation, Fujifilm Wako Pure Chemical Corporation, Chiba Fatty Acids Co., Ltd., etc. can be used. In addition, Struktol WB16 manufactured by Struktol Company can also be used.

[0229] The content of stearic acid is preferably more than 0.5 parts by mass and less than 10.0 parts by mass relative to 100 parts by mass of the rubber component.

[0230] (⑦) Zinc oxide

[0231] The rubber composition may contain zinc oxide. The content of zinc oxide is, for example, more than 0.5 parts by mass and less than 10 parts by mass relative to 100 parts by mass of the rubber component. As zinc oxide, conventionally known substances can be used. Products of Mitsui Mining & Smelting Co., Ltd., Toho Zinc Co., Ltd., HAKUSUI TECH Co., Ltd., Sho Do Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc. can be used.

[0232] (⑧) Crosslinking agent and vulcanization accelerator

[0233] 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 relative to 100 parts by mass of the rubber component. It should be noted that the content of sulfur is the pure sulfur component, and in the case of using insoluble sulfur, it is the content after removing the oil component.

[0234] Examples of sulfur include powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, soluble sulfur, etc., which are commonly used in the rubber industry. They can be used alone or in combination of two or more.

[0235] It should be noted that as sulfur, products of, for example, Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Kasei Kogyo Co., Ltd., Flexis Co., Ltd., Nippon Karyu Kogyo Co., Ltd., Hosoi Chemical Industry Co., Ltd., etc. can be used.

[0236] Crosslinking agents other than sulfur can also be used. Specifically, for example, TACKROLV200 manufactured by Tago Chemical Industry Co., Ltd., DURALINK HTS (1,6 - hexamethylene - disodium dithiocarbamate dihydrate) manufactured by Flexis Co., Ltd., KA9188 (1,6 - bis(N,N’ - dibenzylthiocarbamoyl disulfide): hybrid crosslinking agent) manufactured by LANXESS Co., Ltd., etc., which are sulfur - containing vulcanizing agents, and organic peroxides such as dicumyl peroxide can be used.

[0237] Moreover, 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 relative to 100 parts by mass of the rubber component.

[0238] Examples of the vulcanization accelerator include thiazole - type vulcanization accelerators such as 2 - mercaptobenzothiazole, di - 2 - benzothiazolyl disulfide, N - cyclohexyl - 2 - benzothiazolyl sulfenamide; thiuram - type vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), tetra(2 - ethylhexyl)thiuram disulfide (TOT - N); sulfenamide - type vulcanization accelerators such as N - cyclohexyl - 2 - benzothiazole sulfenamide, N - tert - butyl - 2 - benzothiazolyl sulfenamide, N - ethylene oxide - 2 - benzothiazole sulfenamide, N - ethylene oxide - 2 - benzothiazole sulfenamide, N,N’ - diisopropyl - 2 - benzothiazole sulfenamide; guanidine - type vulcanization accelerators such as diphenylguanidine, di - o - tolylguanidine, o - tolylbiguanide. They can be used alone or in combination of two or more.

[0239] (⑨) Others

[0240] In the rubber composition, in addition to the above components, additives commonly used in the tire industry, such as organic fillers like cellulose fibers, organic peroxides, etc., can be blended as needed. The content of these additives is, for example, more than 0.1 part by mass and less than 50 parts by mass relative to 100 parts by mass of the rubber component.

[0241] It should be noted that various materials containing carbon atoms in the above materials (such as rubber, oil, resin, vulcanization accelerator, anti-aging agent, surfactant, etc.) can be derived from carbon dioxide in the atmosphere. As a method for obtaining the blend of the present invention from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through a methanation process for synthesizing methane via carbon dioxide can be converted.

[0242] After treating the cap ply cord with an adhesive and bonding it to a specified rubber composition for the cap ply, a cap ply can be formed.

[0243] (2) Preparation of the rubber composition

[0244] The rubber composition can be prepared by a general method, for example, a manufacturing method including a basic kneading process of kneading a rubber component and a filler such as silica, and a refining kneading process of kneading the kneaded product obtained in the above basic kneading process and a crosslinking agent.

[0245] Kneading can be carried out using a known (closed-type) kneader such as a Banbury mixer, a kneader, an open mill, etc.

[0246] The kneading temperature in the basic kneading process is, for example, more than 50°C and less than 200°C, and the kneading time is, for example, more than 30 seconds and less than 30 minutes. In the basic kneading process, in addition to the above components, compounding agents used in the existing rubber industry, such as softeners like oil, stearic acid, zinc oxide, anti-aging agents, waxes, vulcanization accelerators, etc., can be appropriately added as needed and kneaded.

[0247] In the refining kneading process, the kneaded product obtained in the above basic kneading process and the crosslinking agent are kneaded. The kneading temperature in the refining kneading process is, for example, more than room temperature and less than 80°C, and the kneading time is, for example, more than 1 minute and less than 15 minutes. In the refining kneading process, in addition to the above components, vulcanization accelerators, zinc oxide, etc. can be appropriately added as needed and kneaded.

[0248] 3. Manufacture of the tire

[0249] The tire of the present embodiment can be manufactured by a conventional method. First, using the rubber composition obtained above, the tread is formed in such a manner that the rubber hardness (Shore hardness) Hs exceeds 70 pt as described above. As a method for adjusting the rubber hardness (Shore hardness) Hs of the tread, for example, the rubber hardness (Shore hardness) Hs of the tread can be increased by increasing the compounding amount of fillers such as silica or carbon in the rubber composition, increasing the compounding amount of the crosslinking agent, or decreasing the compounding amount of the plasticizer (oil or resin, etc.). The tread can be formed by extrusion processing, for example. Next, it is combined with other rubber components on a tire molding machine to produce an unvulcanized tire.

[0250] Specifically, on a molding drum, an inner liner layer as a component for ensuring the airtightness of the tire, a carcass as a component for bearing the load, impact, and inflation pressure of the tire, a belt layer component as a component for strongly clamping the carcass and improving the tread rigidity, a crown ply, etc. are wound. While fixing both ends of the carcass at both side edges, a bead portion as a component for fixing the tire to a rim is arranged. After being formed into a ring shape, the tread is attached to the central portion of the outer periphery, and the sidewall is attached to the radially outer side to form a sidewall portion, thereby producing an unvulcanized tire. In the tire of the present embodiment, as described above, the carcass is formed into a single-layer structure using a carcass cord having a total fineness exceeding 2400 dtex. In addition, as the crown ply cord constituting the crown ply, a cord obtained by single-twisting (1×4 structure) filaments having a circular cross-section without corrugation treatment is used.

[0251] Then, the tire is obtained by heating and pressurizing the unvulcanized tire produced above in a vulcanizer. The vulcanization process can be carried out by applying known vulcanization means. As the vulcanization temperature, for example, it exceeds 120°C and is less than 200°C, and the vulcanization time is, for example, more than 5 minutes and less than 15 minutes.

[0252] In the tire obtained above, as described above, by appropriately controlling the sum of the diameter Bar (mm) of the crown ply cord, the diameter Ber (mm) of the belt layer cord, the diameter Car (mm) of the carcass cord, and the thickness Trg (mm) of the tread, the effects brought by the use of the PET crown ply and the effects brought by the appropriately formed tread and carcass act synergistically, and an improvement in the comprehensive performance of low fuel consumption and high-speed durability can be achieved.

[0253] Moreover, the tire of the present invention can be suitably used as a passenger car tire, a large passenger car tire, a large SUV tire, a truck / bus tire, a two-wheeler tire, a racing tire, a studless snow tire (winter tire), an all-season tire, a run-flat tire, etc., and is particularly preferably used as a passenger car tire.

[0254] Examples

[0255] Examples (embodiments) considered preferable in implementation are shown below, but the scope of the present invention is not limited to these embodiments.

[0256] Research was conducted on tires (tire size: 195 / 65R15) composed of treads formed from various compounding materials shown below, as well as tire components such as the crown ply and belt ply. The results calculated based on the evaluation methods described later regarding low fuel consumption and high-speed durability are shown together in the lower part of Table 1.

[0257] 1. Preparation of rubber composition

[0258] Using the various compounding materials shown below, a rubber composition for the tread was prepared.

[0259] (1) Compounding materials

[0260] (a) Rubber components

[0261] (①) NR: TSR20

[0262] (②) SBR: HPR840 manufactured by ENEOS Materials

[0263] (Styrene content: 10% by mass, vinyl content: 42 mol%, Tg: -60 °C, non-extended oil)

[0264] (③) BR: UBEPOL BR (registered trademark) 150B manufactured by Ube Industries, Ltd.

[0265] (b) Compounding materials other than rubber components

[0266] (①) Carbon black: DIABLACK N220 manufactured by Mitsubishi Chemical Corporation

[0267] (N2SA: 115 m 2 / g)

[0268] (②) Silica: ULTRASIL VN3 manufactured by Evonik Industries AG

[0269] (N2SA: 175 m 2 / g, average primary particle size: 17 nm)

[0270] (③) Coupling agent: NXT manufactured by Momentive

[0271] (3-octanoylthiopropyltriethoxysilane)

[0272] (④) Oil: Mineral oil A / OMIX manufactured by Sankyo Yuka Kogyo Co., Ltd.

[0273] (⑤) Resin: YS Resin PX850 manufactured by Yasuhara Chemical Co., Ltd.

[0274] (Softening point 85°C, β-pinene resin (terpene resin))

[0275] (⑥) Wax: OZOACE 0355 manufactured by Nippon Seiro Co., Ltd.

[0276] (⑦) Antioxidant-1: NOCRAC 6C manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

[0277] (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine)

[0278] (⑧) Antioxidant-2: ANTAGE RD manufactured by Kawaguchi Chemical Industry Co., Ltd.

[0279] (Poly(2,2,4-trimethyl-1,2-dihydroquinoline)

[0280] (⑨) Stearic acid: Bead stearic acid "Tsubaki" manufactured by NOF Corporation

[0281] (⑩) Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd.

[0282] Sulfur: Powder sulfur manufactured by Karuizawa Sulfur Co., Ltd.

[0283] Vulcanization accelerator-1: NOCCELER CZ manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

[0284] (N-cyclohexylbenzothiazole-2-sulfenamide)

[0285] Vulcanization accelerator-2: NOCCELER D manufactured by Ouchi Shinko Chemical Industrial Co., Ltd.

[0286] (N,N'-diphenylguanidine)

[0287] (2) Preparation of the rubber composition for tread

[0288] Based on the respective ratios of A to C shown in Table 1, using a 1.7 L Banbury mixer manufactured by Kobe Steel, Ltd., the materials other than sulfur and vulcanization accelerator were kneaded at 150°C for 5 minutes to obtain a kneaded product.

[0289] Next, sulfur and vulcanization accelerator were added to the kneaded product, and it was kneaded at 80°C for 5 minutes using a two-roll mill to obtain the rubber compositions for tread with ratios A to C.

[0290] 2. Molding of tire components (tread, crown ply, belt ply)

[0291] (1) Molding of the tread

[0292] Next, using the rubber composition obtained above, the tread is molded with each thickness shown in Table 2.

[0293] (2) Molding of the belt layer

[0294] Meanwhile, the specified rubber composition for the belt layer is applied to each belt layer cord shown in Table 2, and each belt layer is molded.

[0295] (3) Molding of the carcass ply

[0296] Similarly, the specified rubber composition for the carcass ply is applied to each carcass ply cord shown in Table 2, and each carcass ply is molded.

[0297] 3. Manufacture of the tire

[0298] Next, the obtained treads, belt layers, and carcass plies are assembled with other tire components to form an unvulcanized tire, which is then press-vulcanized at 170 °C for 10 minutes to manufacture the test tires of Examples 1 to 4 and Comparative Examples 1 to 6.

[0299] 4. Performance evaluation test

[0300] (1) High-speed durability evaluation

[0301] Each test tire is assembled onto a rim (size = 15×6J), filled with air, and after adjusting the internal pressure to 280 kPa, it is installed on a drum rolling test machine, and a longitudinal load of 4.22 kN is applied. Starting from 200 km / h, the speed is gradually increased in steps of 10 km / h, and the time and speed until the tire is damaged are measured. The time obtained is divided by the time taken to increase to the next speed, multiplied by 10 km / h, and the resulting value is added to the obtained speed to calculate the total value. The index with the result of Comparative Example 1 set to 100 is used as the index for high-speed durability.

[0302] Next, with the result of Comparative Example 1 set to 100, it is indexed based on the following formula for high-speed durability evaluation. The larger the value, the better the high-speed durability.

[0303] High-speed durability evaluation = [(Result of the test tire) / (Result of Comparative Example 1)] × 100

[0304] (2) Low fuel consumption evaluation

[0305] Using a rolling resistance testing machine, for each test tire, the rolling resistance coefficient (RRC: Rolling Resistance Coefficient) was measured when traveling on a drum at a speed of 80 km / h under the following conditions.

[0306] Rim used: 15×6J

[0307] Internal pressure: 210 kPa

[0308] Load: 4.35 kN

[0309] Next, taking the result in Comparative Example 1 as 100, it was exponentiated based on the following formula for the low fuel consumption evaluation. The larger the value, the more excellent the low fuel consumption performance.

[0310] Low fuel consumption evaluation = [(Result of Comparative Example 1) / (Result of the test tire)] × 100

[0311] (3) Comprehensive evaluation

[0312] Furthermore, the results of (1) and (2) were totaled as the comprehensive evaluation. The evaluation results are shown in Table 2.

[0313] [Table 1]

[0314] (parts by mass) Ratio A Ratio B Ratio C NR 16 40 50 SBR 64 50 50 BR 20 10 0 Carbon black 10 10 20 Silica 60 80 110 Coupling agent 3.6 4.8 6.6 Oil 16 8 6 Resin 20 8 4 Wax 2 2 2 Antioxidant - 1 2 2 2 Antioxidant - 2 0.5 0.5 0.5 Processing aid 1 1 1 Stearic acid 2.5 2.5 2.5 Zinc oxide 2 2 2 Sulfur 1.1 1.2 1.2 Vulcanization accelerator - 1 1.7 1.7 1.7 Vulcanization accelerator - 2 1.2 1.5 1.5 Total amount (phr) 222.4 223.7 259.5 Hs (pt) 55 67 77

[0315] [Table 2]

[0316]

[0317] As described above, the present invention has been explained 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.

[0318] The present invention (1) relates to a tire, which comprises:

[0319] A carcass having carcass cords;

[0320] A belt having belt cords and disposed radially outside the carcass of the tire;

[0321] A crown belt having crown belt cords and disposed radially outside the belt of the tire; and

[0322] A tread disposed radially outside the crown belt of the tire,

[0323] The tire is characterized in that

[0324] The above-mentioned crown belt cords contain polyethylene terephthalate fibers,

[0325] The above carcass is formed using carcass cords with a total fineness exceeding 2400 dtex.

[0326] The above tread is formed using a rubber composition containing more than 20 parts by mass of isoprene rubber in 100 parts by mass of the rubber component, and has a rubber hardness (Shore hardness) Hs exceeding 70 pt.

[0327] Furthermore, the sum (Bar + Ber + Car + Trg) of the diameter Bar (mm) of the above cap ply cord, the diameter Ber (mm) of the above belt ply cord, the diameter Car (mm) of the above carcass cord, and the thickness Trg (mm) of the above tread is less than 20.

[0328] The tire according to the present invention (2), as described in the present invention (1), is characterized in that the above carcass is formed into a single-layer structure.

[0329] The tire according to the present invention (3), as described in the present invention (1), is characterized in that the above belt ply cord is a cord composed of 1 or more and 4 or less filaments.

[0330] The tire according to the present invention (4), as described in the present invention (1), is characterized in that the above rubber hardness (Shore hardness) Hs exceeds 71 pt.

[0331] The tire according to the present invention (5), as described in the present invention (4), is characterized in that the above rubber hardness (Shore hardness) Hs exceeds 73 pt.

[0332] The tire according to the present invention (6), as described in the present invention (5), is characterized in that the above rubber hardness (Shore hardness) Hs exceeds 75 pt.

[0333] The tire according to the present invention (7), as described in the present invention (1), is 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.

[0334] The tire according to the present invention (8), as described in the present invention (1), is characterized in that the above polyethylene terephthalate fiber is a sustainable polyethylene terephthalate fiber.

[0335] The tire according to the present invention (9), as described in the present invention (1), is characterized in that the above rubber composition contains vegetable oil.

[0336] The tire according to the present invention (10), as described in the present invention (1), is characterized in that the above rubber composition contains sustainable carbon black.

[0337] The tire according to the present invention (11), as described in the present invention (1), is characterized in that the above rubber composition contains sustainable silica.

[0338] Symbol Explanation

[0339] 1 Tire

[0340] 2 Tread

[0341] 3 Sidewall

[0342] 4 Abrasion Protection Part

[0343] 5 Bead

[0344] 6 Innerliner

[0345] 7 Carcass

[0346] 8 Belt

[0347] 9 Filler

[0348] 10 Apex

[0349] Equatorial Plane of CL Tire

Claims

1. A tire, comprising: A carcass having carcass cords; a belt layer including belt layer cords and arranged on the tire radial direction outer side of the carcass; a cap layer including cap layer cords and disposed on the outer side of the belt layer in the tire radial direction; and A tread, which is arranged on the outer side of the cap layer in the tire radial direction, The tire is characterized by: The cap layer cords include polyethylene terephthalate fibers, The carcass is formed by using carcass cords with a total fineness exceeding 2400 dtex, The tread is formed by using a rubber composition containing more than 20 parts by mass of isoprene-based rubber per 100 parts by mass of the rubber component, and has a rubber hardness, that is, a Shore hardness Hs, of more than 70 pt. Further, the sum of the diameter Bar of the cap layer cord, the diameter Ber of the belt layer cord, the diameter Car of the carcass cord and the thickness Trg of the tread Bar+Ber+Car+Trg is less than 20, wherein, The units of the diameter Bar, the diameter Ber, the diameter Car and the thickness Trg are mm.

2. The tire according to claim 1, characterized in that The carcass is formed into a 1-layer structure.

3. The tire according to claim 1, characterized in that The belt cords are cords composed of one or more and four or less filaments.

4. The tire according to claim 1, characterized in that The rubber hardness, that is, the Shore hardness Hs, exceeds 71 ​​pt.

5. The tire according to claim 4, characterized in that The rubber hardness, that is, the Shore hardness Hs, exceeds 73 pt.

6. The tire according to claim 5, characterized in that The rubber hardness, that is, the Shore hardness Hs, exceeds 75 pt.

7. The tire according to claim 1, characterized in that The ratio of the tire weight to the maximum load-bearing capacity of the tire, ie, tire weight / maximum load-bearing capacity, is less than 0.02, wherein the unit of the tire weight is kg, and the unit of the maximum load-bearing capacity is kg.

8. The tire according to claim 1, characterized in that The polyethylene terephthalate fiber is a sustainable polyethylene terephthalate fiber.

9. The tire according to claim 1, characterized in that The rubber composition contains vegetable oil.

10. The tire according to claim 1, characterized in that The rubber composition contains sustainable carbon black.

11. The tire according to claim 1, characterized in that The rubber composition contains sustainable silica.

Images