Tire

Abstract

The invention provides a tire. The purpose of the present invention is to further improve the steering stability during high-speed travel of a tire in which sustainable cords are used among the ply cords of a carcass ply. Provided is a tire provided with a tread section having a crown rubber layer and a carcass section, in which sustainable polyester cords are used as ply cords in a carcass ply constituting the carcass section. The complex elastic modulus E * (MPa) and the thickness A (mm) of the center part of the tread part of the crown rubber layer, which are measured under the conditions of a temperature of 30 DEG C, an initial strain of 5%, a dynamic strain of 1%, a frequency of 10 Hz, and a deformation mode: elongation, satisfy the following formula. E * / A > = 1.3.

Description

Technical Field

[0001] This invention relates to tires. Background Technology

[0002] In recent years, there has been a strong demand for reducing environmental burden and saving resources. As a component of the tire carcass, sustainable cords such as cords derived from biological sources and recycled cords have been studied (e.g., Patent Document 1).

[0003] On the other hand, with the improvement of highways in recent years, it is not uncommon to travel long distances on highways. In this case, the requirements for handling stability at high speeds are very high, and various solutions have been proposed (such as patent documents 2 and 3).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2023-23658

[0007] Patent Document 2: Japanese Patent No. 4621127

[0008] Patent Document 3: Japanese Patent Application Publication No. 2023-021772 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, tires that use sustainable cords in the carcass ply do not yet have sufficient handling stability at high speeds, and further improvements are needed.

[0011] The objective of this invention is to further improve the handling stability of tires that use sustainable cords in the carcass ply cords at high speeds.

[0012] Methods for solving problems

[0013] This invention relates to a tire having a tread portion having a crown rubber layer and a carcass portion, characterized in that,

[0014] In the tire carcass ply that constitutes the aforementioned tire carcass portion, sustainable polyester cords are used as the ply cords.

[0015] The complex elastic modulus E of the aforementioned crown rubber layer was measured under the following conditions: temperature 30℃, initial strain 5%, dynamic strain 1%, frequency 10Hz, and deformation mode: tension. * The thickness A (mm) of the center part of the tread area (MPa) and the thickness A (mm) of the tread area satisfy the following formula.

[0016] E* / A≥1.3

[0017] Invention Effects

[0018] According to the present invention, it is possible to further improve the handling stability performance of tires that use sustainable cords in the carcass ply cords at high speeds. Attached Figure Description

[0019] Figure 1 This is a schematic cross-sectional view illustrating the structure of a tire according to one embodiment of the present invention. Detailed Implementation

[0020] [1] Features of the tire of the present invention

[0021] First, the features of the tire of the present invention will be described.

[0022] 1. Summary

[0023] The tire of the present invention comprises a tread portion having a crown rubber layer and a carcass portion. In the carcass ply constituting the carcass portion, sustainable polyester cords are used as ply cords. Furthermore, the complex elastic modulus E of the crown rubber layer was measured under the following conditions: temperature 30°C, initial strain 5%, dynamic strain 1%, frequency 10Hz, and deformation mode: tension. * The thickness A (mm) of the center portion of the tread (MPa) and the center portion of the tread (tread center portion) satisfy the following formula.

[0024] E * / A≥1.3

[0025] By incorporating these features, as described later, it is possible to further improve the handling stability of tires using sustainable cords in the ply cords at high speeds.

[0026] 2. The mechanism of the effect in the tire of the present invention

[0027] The mechanism by which the tire of the present invention improves handling stability is considered as follows.

[0028] (1) Use of sustainable cords in the carcass ply

[0029] In this invention, as described above, sustainable polyester cords are used as cords in the tire carcass ply that constitute the tire carcass.

[0030] Here, "sustainable polyester cord" refers to recycled polyester cord made from plastic waste such as PET bottles or old clothes, or polyester cord made from biological raw materials, which can reduce environmental burden and save resources.

[0031] However, sustainable polyester cords may not be able to fully realize their performance due to differences in raw materials and / or manufacturing methods compared to general-purpose polyethylene terephthalate cords.

[0032] (2) The complex elastic modulus of the crown rubber layer and the thickness of the center of the tread

[0033] Therefore, in this invention, as described above, the complex elastic modulus E of the crown rubber layer is measured under the conditions of a temperature of 30°C, an initial strain of 5%, a dynamic strain of 1%, a frequency of 10Hz, and a deformation mode of elongation. * The thickness A (mm) of the center part of the tread area and the pressure (MPa) satisfy the following formula.

[0034] E * / A≥1.3

[0035] Complex elastic modulus E * It is a parameter representing the rigidity of the rubber layer, determined by the complex elastic modulus E of the crown rubber layer. * The thickness A relative to the center of the tread increases to 1.3 or more (E * Even with a tire carcass ply made of sustainable polyester cord (A≥1.3), the tread can deform sufficiently to ensure that the road surface and the tire tread surface make roughly uniform contact. Therefore, it is believed that further improvement in handling stability at high speeds can be achieved.

[0036] It should be noted that, as mentioned above, the complex elastic modulus can be determined as follows: a test piece with a length of 20mm × width of 4mm × thickness of 1mm is cut from the crown rubber layer of the tire tread with the tire circumference as the long side and the tire radius as the thickness direction. The test piece is then measured using a dynamic viscoelasticity measuring device (such as the EPLEXOR series manufactured by GABO Corporation, a registered trademark).

[0037] In addition, the thickness of the center part of the tread refers to the thickness of the tread portion on the tire equatorial plane in the tire radial direction section. When there is a groove on the tire equatorial plane, it refers to the thickness of the tread portion at the interface between the intersection of the straight line connecting the outermost end of the tire radial direction connecting the groove and the tire equatorial plane.

[0038] It should be noted that the tread portion refers to the component that forms the contact patch with the tire, and specifically the portion further outward in the radial direction from components containing fibrous materials such as the carcass, belt ply, and belt reinforcement ply. The thickness of the tread portion can be measured by ensuring that the bead portion matches the width of a standard rim on a cross-section cut radially from the tire.

[0039] Here, "standard rim" refers to the rim specified for each tire within a standard system that includes the standard upon which the tire is based. For example, if it's JATMA (Japan Automobile Tire Association), it refers to the standard rim with applicable dimensions listed in the "JATMA YEAR BOOK"; if it's ETRTO (The European Tyre and Rim Technical Organization), it refers to the "Measuring Rim" listed in the "STANDARDS MANUAL"; and if it's TRA (The Tire and Rim Association, Inc.), it refers to the "Design Rim" listed in the "YEAR BOOK". The reference order is JATMA, ETRTO, then TRA. If applicable dimensions are available, that standard is followed. Additionally, in cases where the standard does not specify a rim, it refers to the rim with the smallest diameter and second narrowest width among rims that can be assembled and maintain internal pressure—that is, rims that do not leak air between the rim and tire.

[0040] [2] A more preferred embodiment of the tire of the present invention

[0041] The tire of the present invention can achieve greater effects by employing the following methods.

[0042] 1. Multi-layered tread

[0043] In this invention, the tread can be formed by only one crown rubber layer that contacts the road surface, or it can be formed by setting a base rubber layer inside the crown rubber layer to form two layers. Alternatively, it can be three layers or more than four layers.

[0044] Thus, when the tread layer is multi-layered, the thickness of the crown rubber layer in the overall tread is preferably 10% or more. This ensures sufficient friction between the tread surface and the road surface, even at high speeds, and effectively transmits the frictional force to the tire interior, thereby improving grip and further enhancing handling stability at high speeds. It should be noted that, considering the friction between the tread surface and the road surface, the thickness of the crown rubber layer is more preferably 70% or more.

[0045] It should be noted that when there are grooves on the equatorial surface of the tire, the proportion of the crown rubber layer thickness in the entire tread can be obtained by calculating the thickness of the crown rubber layer and the thickness of the base rubber layer at the center of the land portion of the tread closest to the equatorial surface.

[0046] Furthermore, the tread portion refers to the component that forms the contact patch of the tire, and specifically refers to the portion further outward in the radial direction from components containing fibrous materials, such as the tire carcass, belt ply, and belt reinforcement ply. The thickness of the tread portion can be measured by ensuring that the bead portion matches the width of a standard rim on a cross-section cut radially from the tire.

[0047] 2. The complex elastic modulus of the crown rubber layer and the thickness of the tread center.

[0048] In this invention, as described above, (E * / A) Controlled to 1.3 or higher (E) * / A≥1.3), more preferably 1.5 or more (E * / A≥1.5). As an upper limit, it is preferred, for example, to be 1.9 or less (E * / A≤1.9), more preferably 1.7 or less (E * / A≤1.7).

[0049] It should be noted that the complex modulus of elasticity of the aforementioned crown rubber layer can be appropriately adjusted by modifying, for example, the amount of styrene, silica, carbon black, and other fillers in the rubber composition constituting the crown rubber layer (crown rubber composition), the content of the softener component, and the content of the resin component. Specifically, for example, increasing the amount of styrene in the rubber component (polymer), increasing the amount of silica, carbon black, and other fillers, decreasing the content of the softener component, and increasing the content of the resin component can improve the complex modulus of elasticity. Conversely, decreasing the amount of styrene in the polymer, decreasing the amount of silica, carbon black, and other fillers, increasing the content of the softener component, and decreasing the content of the resin component can decrease the complex modulus of elasticity.

[0050] 3. Number of cords in the tire tread layer

[0051] In this invention, the number (density) D (columns / 5cm) of the cords (sustainable polyester cords) in the tread layer within a 5cm width perpendicular to its length direction is the same as the above (E) * The product of / A) ((E) * / A)×D) Preferably more than 39((E) * / A)×D>39).

[0052] By controlling ((E) * / A)×D) exceeds 39((E) * / A)×D>39), the effect of the rigidity of the carcass ply layer and (E) * The effects of the control ( / A) work synergistically, thus it is believed that further improvements in handling stability at high speeds can be achieved. More preferably, it is 50 or more ((E)* / A)×D≥50). As an upper limit, it is preferably 65 or less ((E) * / A)×D≤65), more preferably 60 or less ((E) * / A)×D≤60).

[0053] It should be noted that the density of the cords in the above-mentioned ply can be determined according to the method specified in JIS L1017:2002 "Test Method for Cords of Chemical Fiber Tires".

[0054] 4. Cords and their characteristics in fabric layers

[0055] (1) Material

[0056] In this invention, sustainable polyester cords are used as the fabric layer cords, and sustainable polyethylene terephthalate (PET) cords are preferred among various sustainable polyester cords. Sustainable polyethylene terephthalate (PET) cords have high rigidity, and therefore it is believed that further improvements in handling stability can be achieved during high-speed driving.

[0057] (2) Content of isophthalic acid

[0058] In the case of sustainable polyester cords made from recycled polyester cords derived from PET fibers, PET bottles, etc., isophthalic acid, as an impurity, may sometimes be present, potentially leading to instability in the quality of the sustainable polyester cords. Therefore, the isophthalic acid content in sustainable polyester cords is preferably less than 0.1 mol%, and particularly preferably 0.0 mol%. This is considered to obtain sustainable polyester cords with stable quality, which can further improve handling stability at high speeds.

[0059] It should be noted that the isophthalic acid content (IF, mol%) in sustainable polyester cord is different from that mentioned above (E). * / A)×D) preferably satisfies the following formula.

[0060] (E * / A)×D×(100-IF)>5000

[0061] (3) Strength (tensile strength)

[0062] The strength S (cN / dtex) of the sustainable polyester cord is preferably 6.0 cN / dtex or higher. This allows the tire carcass to absorb and suppress tread deformation during high-speed driving, thus further improving handling stability at high speeds. More preferably, it is 6.3 cN / dtex or higher, and even more preferably 6.6 cN / dtex or higher.

[0063] It should be noted that the above strength can be determined according to the method specified in JIS L1017:2002 "Test Method for Chemical Fiber Tire Cords".

[0064] (4) Density and strength

[0065] The product of the strength S (cN / dtex) of the sustainable polyester cord and the density D (cords / 5cm) (S×D) is preferably 160 or more (S×D≥160). This allows the tire carcass to more fully absorb and suppress tread deformation during high-speed driving, thus further improving handling stability at high speeds. More preferably, it is 200 or more (S×D≥200), and even more preferably 250 or more (S×D≥250).

[0066] (5) Intermediate elongation and density

[0067] The intermediate elongation E (%) at a specified load L (cN / dtex) of sustainable polyester cord preferably satisfies the following formula between the density D (cords / 5cm) mentioned above.

[0068] 12≤L×D / E≤20

[0069] By appropriately controlling (L×D / E), the tire carcass portion can more fully absorb and suppress tread deformation during high-speed driving, thus it is believed that further improvements in handling stability at high speeds can be achieved. More preferably, it is 13.5 or more and 18.5 or less (13.5≤L×D / E≤18.5).

[0070] It should be noted that the above-mentioned intermediate elongation can be determined according to the method specified in JIS L1017:2002 "Test Method for Chemical Fiber Tire Cords".

[0071] (6) Elongation at break

[0072] The elongation at break (%) of the sustainable polyester cord is preferably 10% or more. This allows for more thorough absorption and suppression of tread deformation during high-speed driving by utilizing the carcass portion, thus enabling further improvement in handling stability at high speeds. More preferably, it is 12% or more.

[0073] It should be noted that the above-mentioned elongation at break can be determined according to the method specified in JIS L1017:2002 "Test Method for Chemical Fiber Tire Cords".

[0074] (7) Strength retention rate in damp heat resistance

[0075] The moisture and heat resistance strength retention rate (%) of the sustainable polyester cord is preferably 80% or more. This ensures that it can maintain handling stability at high speeds over a long period. More preferably, it is 85% or more, and even more preferably 90% or more.

[0076] It should be noted that the above-mentioned strength retention rate of resistance to damp heat can be calculated by measuring the ratio of the strength after treatment with saturated water vapor at 135°C for 48 hours (damp heat treatment) to the strength before treatment.

[0077] 5. Flatness

[0078] Aspect ratio is the ratio of tire section height to tire section width. The smaller this ratio (lower aspect ratio), the better the contact patch with the road surface, and therefore it is believed to further improve handling stability at high speeds. On the other hand, if the aspect ratio is too low, it may lead to a deterioration in ride comfort.

[0079] Taking these aspects into consideration, the aspect ratio of the tire of the present invention is preferably 30% or more and 60% or less.

[0080] It should be noted that the above aspect ratio (%) can be calculated using the tire's section height Ht (mm), section width Wt (mm), tire outer diameter Dt (mm), and rim diameter R (mm) when the internal pressure is set to 250 kPa, by the following formula.

[0081] Flatness ratio (%) = (Ht / Wt) × 100 (%)

[0082] Ht=(Dt-R) / 2

[0083] 6. Land area

[0084] In the tire of the present invention, the land ratio of the tread portion of the tire assembled into a regular rim and set to a regular internal pressure is preferably 55% or more, more preferably 60% or more, and even more preferably 63% or more.

[0085] The "land ratio" is the ratio of the actual contact area to the imaginary contact area where all the grooves on the tread surface are filled. A larger land ratio means a larger contact area with the road surface, thus improving ground contact and believed to further enhance handling stability at high speeds.

[0086] It should be noted that there is no particular upper limit to the land ratio, but it is preferably 85% or less, more preferably 80% or less, and even more preferably 75% or less.

[0087] The above-mentioned land ratio can be determined based on the grounding shape under normal wheel rim, normal internal pressure, and normal load conditions.

[0088] Specifically, the tire is mounted on a standard rim, a standard internal pressure is applied, and after standing at 25°C for 24 hours, ink is applied to the tire tread surface, a standard load is applied, and the tire is pressed against thick paper (camber angle 0°) to transfer the image onto the paper, thus obtaining the ground contact shape. The tire is then rotated 72° circumferentially, and the image is transferred at five locations, resulting in five ground contact shapes. For each of the five ground contact shapes, the interrupted sections in the contour of the ground contact shape are smoothly connected, and the resulting shape is used as the imaginary ground contact surface.

[0089] Furthermore, the land ratio can be calculated as (average area of ​​the 5 grounding shapes (ink portions) transferred onto the thick paper / average area of ​​the imaginary ground surface obtained from the 5 grounding shapes) × 100 (%).

[0090] In the above text, "standard internal pressure" refers to the air pressure specified by the aforementioned standard for each tire. If it's JATMA, it refers to the maximum air pressure; if it's ETRTO, it refers to "inflation pressure"; and if it's TRA, it refers to the maximum value recorded in the table "TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES". Similar to the case of "standard rim", the reference order is JATMA, ETRTO, then TRA, and the standard is followed. Furthermore, for tires not specified in the standard, it refers to the standard internal pressure (of which 250 kPa or higher) for other tire sizes (tire sizes specified in the standard) for which the aforementioned standard rim is listed as the standard rim. It should be noted that if multiple standard internal pressures of 250 kPa or higher are recorded, the minimum value among them is used.

[0091] Furthermore, "standard load" refers to the load specified for each tire in the standard system, including the standards upon which the aforementioned tires are based. This refers to the maximum mass the tire is allowed to bear. For JATMA, it refers to maximum load capacity; for ETRTO, it refers to "load capacity"; and for TRA, it refers to the maximum value recorded in the table "TIRE LOAD LIMITS ATVARIOUS COLD INFLATION PRESSURES". Similar to the cases of "standard rim" and "standard internal pressure" mentioned above, the standard load is referenced in the order of JATMA, ETRTO, and TRA, and the standard must be followed. In the case of tires not specified in the standard, the standard load W is calculated using the following methods. L .

[0092] V = {(Dt / 2)} 2 -(Dt / 2-Ht) 2}×π×Wt

[0093] W L =0.000011×V+175

[0094] W L Normal load (kg)

[0095] V: Imaginary volume of the tire (mm) 3 )

[0096] Dt: Tire outer diameter Dt (mm)

[0097] Ht: Tire section height (mm)

[0098] Wt: Tire cross-sectional width (mm)

[0099] [3] Implementation

[0100] The present invention will be specifically described below based on the embodiments.

[0101] 1. The tire of this embodiment

[0102] Figure 1 This is a schematic cross-sectional view illustrating the structure of the tire according to this embodiment, showing a radial section of the tire including the axis of rotation in its normal state.

[0103] like Figure 1 As shown, tire 1 includes: a tire body 6, a bead core 5 extending from the tread portion 2 through the sidewall portion 3 to the bead portion 4; and a belt layer 7 disposed on the outer side of the tire body 6 in the tire radial direction and on the inner side of the tread portion 2. It should be noted that C is the centerline.

[0104] The fetal body consists of at least one piece ( Figure 1 The tire carcass consists of one layer of plywood 6A, which is secured by the bead core 5, which folds back from the inside to the outside from the tread portion 2, through the sidewall portion 3, and around the bead portion 4. It should be noted that... Figure 1 In the middle, 6a is the inner main body of the carcass ply 6A, and 6b is the outer fold-back part. Between the inner main body 6a and the outer fold-back part 6b, there is a bead triangle rubber 8 that extends outward from the bead core 5 in the radial direction of the tire.

[0105] In this embodiment, the carcass ply 6A uses sustainable polyester cord as the ply cord, and is constructed by covering both sides of the sustainable polyester cord arrangement that is stretched at a specified density with coated rubber.

[0106] By using such a carcass ply to form the carcass portion, and appropriately forming the thickness of the tread center portion in the crown rubber layer having the aforementioned complex elastic modulus, it is possible to further improve the handling stability performance of tires using sustainable ply cords at high speeds.

[0107] 2. Rubber composition forming the crown rubber layer (crown rubber composition)

[0108] In this embodiment, the crown rubber composition can be obtained by mixing various blending materials such as rubber components, reinforcing agents, anti-aging agents, oils, resin materials, and anti-aging agents.

[0109] (1) Mixed materials

[0110] (a) Rubber composition

[0111] There are no particular limitations on the rubber components used; for example, isoprene-based rubbers (natural rubber (NR), isoprene rubber (IR), etc.), styrene-butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), and other diene-based rubbers can be used. They can be used alone or in combination of two or more. In this invention, it is preferred to use NR, SBR, and BR in combination.

[0112] (①)SBR

[0113] The weight-average molecular weight of the SBR is, for example, greater than 100,000 and less than 2,000,000. The styrene content of the SBR is preferably greater than 5% by mass, more preferably greater than 10% by mass, and even more preferably greater than 15% by mass. On the other hand, it is preferably less than 40% by mass, more preferably less than 35% by mass, and even more preferably less than 30% by mass. The vinyl content (1,2-bonded butadiene unit weight) of the SBR is preferably greater than 5% by mass, more preferably greater than 10% by mass, and even more preferably greater than 15% by mass. On the other hand, it is preferably less than 70% by mass, more preferably less than 40% by mass, and even more preferably less than 30% by mass. It should be noted that the structural identification of the SBR (determination of styrene content and vinyl content) can be performed, for example, using a JNM-ECA series device manufactured by Nippon Egis Corporation.

[0114] There are no particular limitations on SBR; emulsion-polymerized styrene-butadiene rubber (E-SBR) and solution-polymerized styrene-butadiene rubber (S-SBR) can be used. SBR can be either unmodified or modified. Alternatively, hydrogenated SBR can be obtained by hydrogenating the butadiene portion of SBR. Hydrogenated SBR can also be obtained by subsequently hydrogenating the BR portion of SBR, or by copolymerizing styrene, ethylene, and butadiene to obtain the same structure.

[0115] As a modified SBR, an SBR having functional groups that interact with fillers such as silica is preferred. Examples include, for instance, an end-modified SBR obtained by modifying at least one end of an SBR with a compound (modifier) ​​having the aforementioned functional groups (an end-modified SBR with the aforementioned functional groups at the end); a main-chain modified SBR with the aforementioned functional groups in the main chain; a main-chain end-modified SBR with the aforementioned functional groups in both the main chain and the end (e.g., a main-chain end-modified SBR with the aforementioned functional groups in the main chain and at least one end modified with the aforementioned modifier); and an end-modified SBR modified (coupled) by means of a polyfunctional compound having two or more epoxy groups in the molecule, or by introducing hydroxyl groups, epoxy groups, etc.

[0116] Examples of functional groups mentioned above include amino, amide, silyl, alkoxysilyl, isocyanate, imino, imidazo, urea, ether, carbonyl, oxycarbonyl, mercapto, thioether, dithio, sulfonyl, sulfinyl, thiocarbonyl, ammonium, imide, hydrazine, azo, diazo, carboxyl, nitrile, pyridyl, alkoxy, hydroxyl, oxygen, and epoxy groups. It should be noted that these functional groups may contain substituents.

[0117] Alternatively, as a modified SBR, an SBR modified with, for example, a compound (modifier) ​​represented by the following formula can be used.

[0118] [Chemistry 1]

[0119]

[0120] It should be noted that, in the formula, R 1 R 2 and R 3 Same or different, indicating alkyl, alkoxy, silyloxy, acetal, carboxyl (-COOH), mercapto (-SH) or their derivatives. R 4 and R 5 Same or different, indicating hydrogen atoms or alkyl groups. R 4 and R 5 It can bond with nitrogen atoms to form a ring structure. n represents an integer.

[0121] As a modified SBR modified by the compound (modifier) ​​represented by the above formula, an SBR obtained by modifying the polymerization end (active end) of solution-polymerized styrene-butadiene rubber (S-SBR) with the compound represented by the above formula (such as the modified SBR described in Japanese Patent Application Publication No. 2010-111753).

[0122] As R 1 R 2 and R 3Suitable for use as an alkoxy group (preferably with 1 to 8 carbon atoms, more preferably with 1 to 4 carbon atoms). As R 4 and R 5 Suitable for use as an alkyl group (preferably an alkyl group with 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and even more preferably 3. Additionally, in R... 4 and R 5 When the alkoxy group forms a ring structure with the nitrogen atom through bonding, a 4- to 8-membered ring is preferred. It should be noted that alkoxy groups also include cycloalkoxy groups (such as cyclohexyloxy groups) and aryloxy groups (such as phenoxy and benzyloxy groups).

[0123] Specific examples of the aforementioned modifiers include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. These can be used individually or in combination of two or more.

[0124] Additionally, modified SBRs can also be made from the following compounds (modifiers). Examples of modifiers include polyglycidyl ethers of polyols 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 phenolic groups, such as diglycidylated bisphenol A; polyepoxide compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxide liquid polybutadiene; tertiary amines containing epoxy groups such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; and diglycidyl aniline, N,N'-diglycidyl... Diglycidylamino compounds such as glyceryl-4-epoxypropoxyaniline, diglycidyl-o-toluidine, tetraglycidyl-m-phenylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-diaminomethylcyclohexane; amino-containing acyl chlorides such as bis-(1-methylpropyl)carbamoyl chloride, 4-morpholine carbamoyl chloride, 1-pyrrolidine carbamoyl chloride, N,N-dimethylcarbamoyl chloride, and N,N-diethylcarbamoyl chloride; and 1,3-bis-(epoxypropoxypropyl)-tetramethyldisiloxane, (3-epoxypropoxy... Epoxy-containing silane compounds such as (trimethylsilyl)-pentamethyldisiloxane; (trimethylsilyl)[3-(trimethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl] sulfide, (trimethylsilane) Silane compounds containing thioether groups, such as (trimethylsilyl)[3-(methyldipropoxysilyl)propyl] sulfide and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl] sulfide; N-substituted nitrogen-containing heterocyclic propane compounds, such as aproidine and acrylamide; 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;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, and other (thio)benzophenone compounds having an amino group and / or substituted amino group; 4-N,N-dimethylamino Benzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde, and other benzaldehyde compounds containing amino groups and / or substituted amino groups; N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone, and other N-substituted pyrrolidones; N-methyl-2-piperidinone, N-vinyl-2-piperidinone, N-phenyl-2-piperidinone N-substituted piperidinones; 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, and N-phenyl-β-propiolactam; as well as 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-Triones, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylvinylurea, 1,3-divinylvinylurea, 1,3-diethyl-2-imidazolinone, 1-methyl-3-ethyl-2-imidazolinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone, etc. It should be noted that modification using the above compounds (modifiers) can be carried out using known methods.

[0125] As an SBR (Self-Borne Technology Reactor), SBRs manufactured and sold by companies such as Sumitomo Chemical Co., Ltd., ENEOS Materials Co., Ltd., Asahi Kasei Corporation, and Zeon Corporation can be used. It should be noted that SBRs can be used alone or in combination with two or more other types.

[0126] The SBR content in 100 parts by weight of the rubber component is preferably 40 parts by weight or more, more preferably 45 parts by weight or more, and even more preferably 50 parts by weight or more. As an upper limit, it is preferably 70 parts by weight or less, more preferably 65 parts by weight or less, and even more preferably 60 parts by weight or less.

[0127] (②) Isoprene rubber

[0128] As for isoprene-based rubbers, examples include natural rubber (NR), isoprene rubber (IR), modified NR, modified NR, and modified IR. From the perspective of superior strength, NR is preferred.

[0129] For NR (Normally Induced Rubber), commonly used NRs in the tire industry, such as SVR-L, SIR20, RSS#3, and TSR20, can be used. For IR (Induced Rubber), there are no particular limitations; commonly used IRs in the tire industry, such as IR2200 manufactured by Zeon Corporation of Japan, can be used. Examples of modified NRs include deproteinized natural rubber (DPNR) and high-purity natural rubber (UPNR). Examples of modified NRs include epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), and grafted natural rubber. Examples of modified IRs include epoxidized isoprene rubber, hydrogenated isoprene rubber, and grafted isoprene rubber. These can be used individually or in combination of two or more.

[0130] The content of isoprene-based rubber in 100 parts by weight of the rubber component is preferably 5 parts by weight or more, more preferably 10 parts by weight or more. As an upper limit, it is preferably 50 parts by weight or less, more preferably 30 parts by weight or less.

[0131] (③)BR

[0132] The weight-average molecular weight of BR is, for example, greater than 100,000 and less than 2,000,000. The vinyl content of BR is, for example, greater than 1% by mass and less than 30% by mass. The cis content of BR is, for example, greater than 1% by mass and less than 98% by mass. The trans content of BR is, for example, greater than 1% by mass and less than 60% by mass. It should be noted that the cis content can be determined by infrared absorption spectroscopy.

[0133] There are no particular limitations on the type of BR used; BR with high cis content (cis content of 90% or more), BR with low cis content, BR containing syndiotactic polybutadiene crystals, etc., can be used. BR can be any of unmodified BR or modified BR. As a modified BR, BR can be obtained by modification with, for example, a compound (modifier) ​​represented by the following formula.

[0134] [Chemistry 2]

[0135]

[0136] It should be noted that, in the formula, R 1 R 2 and R 3 Same or different, indicating alkyl, alkoxy, silyloxy, acetal, carboxyl (-COOH), mercapto (-SH) or their derivatives. R 4 and R 5 Same or different, indicating hydrogen atoms or alkyl groups. R4 and R 5 It can bond with nitrogen atoms to form a ring structure. n represents an integer.

[0137] As an example of a modified BR obtained by modifying the polymer end (active end) with the compound (modifier) ​​represented by the above formula, a BR obtained by modifying the polymer end (active end) with the compound represented by the above formula can be cited.

[0138] As R 1 R 2 and R 3 Suitable for use as an alkoxy group (preferably with 1 to 8 carbon atoms, more preferably with 1 to 4 carbon atoms). As R 4 and R 5 Suitable for use as an alkyl group (preferably an alkyl group with 1 to 3 carbon atoms). n is preferably 1 to 5, more preferably 2 to 4, and even more preferably 3. Additionally, in R... 4 and R 5 When the alkoxy group forms a ring structure with the nitrogen atom through bonding, a 4- to 8-membered ring is preferred. It should be noted that alkoxy groups also include cycloalkoxy groups (such as cyclohexyloxy groups) and aryloxy groups (such as phenoxy and benzyloxy groups).

[0139] Specific examples of the aforementioned modifiers include 2-dimethylaminoethyltrimethoxysilane, 3-dimethylaminopropyltrimethoxysilane, 2-dimethylaminoethyltriethoxysilane, 3-dimethylaminopropyltriethoxysilane, 2-diethylaminoethyltrimethoxysilane, 3-diethylaminopropyltrimethoxysilane, 2-diethylaminoethyltriethoxysilane, and 3-diethylaminopropyltriethoxysilane. These can be used individually or in combination of two or more.

[0140] Alternatively, modified BRs obtained by modifying the following compounds (modifiers) can also be used as modified BRs. Examples of modifiers include polyglycidyl ethers of polyols 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 phenolic groups, such as diglycidylated bisphenol A; polyepoxide compounds such as 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, and polyepoxide liquid polybutadiene; tertiary amines containing epoxy groups such as 4,4'-diglycidyl-diphenylmethylamine and 4,4'-diglycidyl-dibenzylmethylamine; diglycidyl aniline, N,N'-diglycidyl... Diglycidylamino compounds such as glyceryl-4-epoxypropoxyaniline, diglycidyl-o-toluidine, tetraglycidyl-m-phenylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, and tetraglycidyl-1,3-diaminomethylcyclohexane; amino-containing acyl chlorides such as bis-(1-methylpropyl)carbamoyl chloride, 4-morpholine carbamoyl chloride, 1-pyrrolidine carbamoyl chloride, N,N-dimethylcarbamoyl chloride, and N,N-diethylcarbamoyl chloride; and 1,3-bis-(epoxypropoxypropyl)-tetramethyldisiloxane, (3-epoxypropoxy... Epoxy-containing silane compounds such as (trimethylsilyl)-pentamethyldisiloxane; (trimethylsilyl)[3-(trimethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(triethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(tripropoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(tributoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(methyldimethoxysilyl)propyl] sulfide, (trimethylsilyl)[3-(methyldiethoxysilyl)propyl] sulfide, (trimethylsilane) Silane compounds containing thioether groups, such as (trimethylsilyl)[3-(methyldipropoxysilyl)propyl] sulfide and (trimethylsilyl)[3-(methyldibutoxysilyl)propyl] sulfide; N-substituted nitrogen-containing heterocyclic propane compounds, such as aproidine and acrylamide; 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;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, and other (thio)benzophenone compounds having an amino group and / or substituted amino group; 4-N,N-dimethylamino Benzaldehyde, 4-N,N-diphenylaminobenzaldehyde, 4-N,N-divinylaminobenzaldehyde, and other benzaldehyde compounds containing amino groups and / or substituted amino groups; N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-phenyl-2-pyrrolidone, N-tert-butyl-2-pyrrolidone, N-methyl-5-methyl-2-pyrrolidone, and other N-substituted pyrrolidones; N-methyl-2-piperidinone, N-vinyl-2-piperidinone, N-phenyl-2-piperidinone N-substituted piperidinones; 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, and N-phenyl-β-propiolactam; as well as 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-Triones, N,N-diethylacetamide, N-methylmaleimide, N,N-diethylurea, 1,3-dimethylvinylurea, 1,3-divinylvinylurea, 1,3-diethyl-2-imidazolinone, 1-methyl-3-ethyl-2-imidazolinone, 4-N,N-dimethylaminoacetophenone, 4-N,N-diethylaminoacetophenone, 1,3-bis(diphenylamino)-2-propanone, 1,7-bis(methylethylamino)-4-heptanone, etc. It should be noted that modification using the above compounds (modifiers) can be carried out using known methods. It should also be noted that these modified BRs can be used alone or in combination of two or more.

[0141] As a BR (Brandinger), products from companies such as Ube Industries, Ltd., ENEOS Materials Co., Ltd., Asahi Kasei Corporation, and Zeon Corporation can be used.

[0142] The BR content in 100 parts by weight of the rubber component is preferably 5 parts by weight or more, more preferably 10 parts by weight or more. On the other hand, it is preferably 30 parts by weight or less, more preferably 25 parts by weight or less.

[0143] (④) Other rubber components

[0144] In the crown rubber composition, as other rubber components, nitrile rubber (NBR) and other rubbers (polymers) commonly used in tire manufacturing may be included as needed.

[0145] It should be noted that the raw materials (monomers) for the aforementioned synthetic rubbers such as SBR and BR can come 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.

[0146] The monomer obtained through recycling (recycled monomer) is not particularly limited, and examples include recycled isoprene, recycled butadiene, and recycled aromatic vinyl monomers. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl monomers are not particularly limited, and examples include styrene. Preferably, recycled isoprene (recycled isoprene), butadiene (recycled butadiene), and / or recycled styrene (recycled styrene) are used as raw materials.

[0147] There are no particular limitations on the manufacturing method of the recycled monomer; for example, it can be synthesized from recycled naphtha obtained by decomposing rubber products such as tires. Furthermore, there are no particular limitations on the manufacturing method of the recycled naphtha; for example, it can be produced by decomposing rubber products such as tires under high temperature and pressure, by microwave decomposition, or by extraction after mechanical crushing.

[0148] Furthermore, the raw materials (monomers) for synthetic rubbers such as IR, SBR, and BR can be derived from biomass. In this specification, biomass refers to substances derived from natural resources such as plants. There are no particular limitations on biomass; examples include agricultural, forestry, and aquatic products, sugar, sawdust, plant residues after the useful components have been extracted, plant-derived ethanol, and biomass naphtha.

[0149] The term "biomass monomer" is not particularly limited and can include butadiene and aromatic vinyl monomers derived from biomass. Examples of butadiene include 1,2-butadiene and 1,3-butadiene. Examples of aromatic vinyl monomers include styrene. Furthermore, the method of manufacturing biomass monomers is not particularly limited and can include, for example, methods based on biological and / or chemical and / or physical conversions of plants and animals. Examples of biological conversions include fermentation using microorganisms, and examples of chemical and / or physical conversions include conversions using catalysts, conversions using high heat, conversions using high pressure, conversions using electromagnetic waves, conversions using critical liquids, and combinations thereof.

[0150] The term "biomass polymer" is not particularly limited to polymers synthesized from biomass monomer components. 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. Examples of the aforementioned aromatic vinyl monomer / butadiene copolymers include styrene-butadiene rubber synthesized from butadiene derived from biomass and / or styrene derived from biomass.

[0151] The pMC (percent Modern Carbon) measured according to ASTM D6866-10 can be used to determine whether the raw material of the polymer comes from biomass.

[0152] pMC refers to the sample 14 C concentration relative to standard modern carbon (modern standard reference) 14 The C concentration ratio is a value used as an indicator of the proportion of compounds in biomass. The significance of this value is as follows.

[0153] In 1 mole (6.02 × 10⁻⁶) 23 Approximately one trillionth of ordinary carbon atoms, or about 6.02 × 10⁻⁶, are present in each carbon atom. 11 indivual 14 C. 14 Carbon (C) is known as a radioactive isotope, with a half-life of 5730 years that decreases regularly. It would take 226,000 years for it to completely disintegrate. Therefore, after carbon dioxide and other substances in the atmosphere are absorbed and fixed by plants and other organisms, it is believed that over 226,000 years, fossil fuels such as coal, oil, and natural gas will have retained some of the carbon dioxide originally contained in these substances. 14 All carbon (C) has dissolved. Therefore, in the 21st century, fossil fuels such as coal, oil, and natural gas contain absolutely no carbon. 14 Therefore, the chemical substances produced from these fossil fuels do not contain any carbon (C). 14 C element.

[0154] On the other hand, cosmic rays undergo nuclear reactions in the atmosphere, continuously generating... 14 C, in equilibrium with the reduction caused by radiative decay, exists in Earth's atmosphere. 14 The amount of C is constant. Therefore, in the current environment, the matter cycling originates from biomass resources. 14 The C concentration, as described above, is approximately 1 × 10⁻⁶ relative to the total C atom concentration. -12 The values ​​are approximately mol%. Therefore, the proportion of biomass in a compound can be calculated using the difference between these values.

[0155] Should14 C is typically determined as follows. Accelerator mass spectrometry based on a tandem accelerator is used. 13 C concentration ( 13 C / 12 C) 14 C concentration ( 14 C / 12 C) Determination. In this determination, the carbon from naturally occurring cycles in 1950 was used. 14 C concentration as 14 The baseline for C concentration is the modern standard reference. As a specific standard substance, the oxalic acid standard provided by NIST (National Institute of Standards and Technology, USA) is used. The radioactivity of carbon in this oxalic acid (the ratio of carbon to radioactivity per gram of carbon) is then used. 14 The radioactivity intensity of C is distinguished into individual carbon isotopes, for 13 The C correction is a fixed value, and attenuation correction is performed from the Gregorian calendar year 1950 until the date of measurement. The resulting value is used as the standard. 14 The value of C concentration (100%). The ratio of this value to the value of the actual sample measured is called the pMC value.

[0156] Therefore, if rubber is made from materials 100% derived from biomass, although there are regional differences, it is generally not 100% biomass under normal conditions, thus showing a value of approximately 110 pMC. On the other hand, for chemicals derived from fossil fuels such as petroleum, when measuring... 14 At C concentrations, the result shows a value of approximately 0 pMC (e.g., 0.3 pMC). This value corresponds to a biomass ratio of 0% as mentioned above.

[0157] In summary, from an environmental protection (sustainability) perspective, materials such as rubber with high pMC values, i.e., rubber with a high proportion of biomass (sustainable materials), are suitable for use in crown rubber compositions.

[0158] (b) Compound materials other than rubber components

[0159] (①) Filler

[0160] The crown rubber composition preferably contains silica and carbon black as reinforcing agents, but may also contain other fillers as needed, such as calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, vulcanized rubber granules (rubber powder), etc. It should be noted that when using silica, it is preferable to use it in combination with a silane coupling agent.

[0161] (i) Silicon dioxide

[0162] Silica has OH groups on its surface, which can capture ozone, thus improving ozone resistance and tire durability. Furthermore, by containing a large amount (more than 75 parts by mass) of silica, hydrogen bonds are formed between the silica surfaces, and it also interacts with the rubber components. Therefore, forces can be easily generated and transmitted within the rubber during driving, easily transmitting forces generated during cornering, ensuring excellent handling stability.

[0163] From the perspective of achieving good durability, the BET specific surface area of ​​silica is preferably greater than 100 m². 2 / g, more preferably over 130m 2 / g. On the other hand, it is preferable to have less than 250m. 2 / g, more preferably less than 200m 2 / g. It should be noted that the above BET specific surface area is the N2SA value determined by the BET method according to ASTM D3037-93.

[0164] There are no particular limitations on the silica used. For example, silica prepared by the dry method (anhydrous silica) or silica prepared by the wet method (hydrated silica) commonly used in the tire industry can be used. As commercially available products, products from Evonik Industries, Rhodia, Tosoh Silica Co., Ltd., Solvay Japan Co., Ltd., Tokuyama Co., Ltd., etc. can be used.

[0165] There are no particular limitations on the raw materials used for silica. For example, it can be mineral-derived raw materials such as quartz, or biological-derived raw materials such as rice husks (e.g., silica made from biomass materials such as rice husks), or silica recycled from silica-containing products. Among these, hydrated silica prepared by a wet process is preferred due to its high silanol group content. One type of silica can be used alone, or two or more types can be used in combination.

[0166] Silica made from biomass materials (biomass silica) can be obtained, for example, by extracting silicates from rice husk ash obtained from burning rice husks using sodium hydroxide solution, and then filtering, washing, drying, and pulverizing the silica precipitate produced by the reaction with sulfuric acid using the silicates in the same manner as existing wet silica.

[0167] Silica recycled from products containing silica (recycled silica) can be, for example, silica recovered from products containing silica such as electronic components like semiconductors, tires, desiccants, and filter materials like diatomaceous earth. Furthermore, there are no particular limitations on the recycling method; examples include thermal decomposition and decomposition using electromagnetic waves. Of these, silica recovered from electronic components like semiconductors or tires is preferred.

[0168] If silica crystallizes, it becomes insoluble in water and cannot be utilized by silicic acid, which is a component of silica. By managing the combustion temperature and combustion time, the crystallization of silica in rice husk ash can be suppressed (see Japanese Patent Application Publication No. 2009-2594, Akita Prefectural University Online Journal B / 2019, vol.6, pp.216-222, etc.).

[0169] Amorphous silica extracted from rice husks can be commercially available from companies such as Wilmar.

[0170] It should be noted that these silicas can be used alone or in combination with two or more. From an environmental protection perspective, sustainable silicas such as biomass silica obtained from biomass as a raw material and recycled silica obtained from the recycling of old products or waste are more suitable.

[0171] As described above, the content of silica relative to 100 parts by weight of the rubber component is preferably more than 60 parts by weight, more preferably more than 80 parts by weight. As an upper limit, it is preferably less than 150 parts by weight, more preferably less than 130 parts by weight.

[0172] (ii) Silane coupling agents

[0173] When using silica, in order to improve the dispersibility of silica and improve mechanical properties and formability through reaction with silica, it is preferable to use a silane coupling agent.

[0174] As a silane coupling agent, there are no particular limitations, but examples 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, and bis(4-trimethoxysilylpropyl)tetrasulfide. Alkyl butyl 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-dimethylthio Carbamoyl tetrasulfide, 2-triethoxysilyl ethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-triethoxysilyl propyl methacrylate monosulfide and other sulfide systems, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, NXT and NXT-Z manufactured by Momentive, and other thiol-based products, vinyltriethoxysilane and vinyltrimethoxysilane, and 3-amino... Silane coupling agents containing thiocarbonyl groups, such as 3-aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, 3-nitropropyltrimethoxysilane, 3-nitropropyltriethoxysilane, and chlorine-based agents, are preferred. They can be used alone or in combination of two or more.

[0175] Products from companies such as Evonik Industries, Momentive, Shin-Etsu Silicon Co., Ltd., Tokyo Chemical Industry Co., Ltd., AZmax Co., Ltd., and Toray D. Corning Co., Ltd. can be used as silane coupling agents.

[0176] The content of the silane coupling agent relative to 100 parts by weight of silicon dioxide is preferably more than 3 parts by weight, more preferably more than 5 parts by weight, and even more preferably more than 7 parts by weight. As an upper limit, it is preferably less than 15 parts by weight, more preferably less than 12 parts by weight, and even more preferably less than 9 parts by weight.

[0177] (iii) Carbon black

[0178] Carbon black is preferred for use in order to improve tires’ resistance to crack growth, durability, and resistance to UV degradation.

[0179] From the perspective of reinforcing rubber, the nitrogen adsorption specific surface area (N2SA) of carbon black is preferably, for example, 30 m² / s. 2 / g or more, preferably 50m 2 / g or more, further preferably 60m 2 / g or more. On the other hand, from the perspective of pyrogenicity, 250m is preferred. 2 / g or less, more preferably 150m 2 / g or less, more preferably 120m 2 / g or less. It should be noted that the nitrogen adsorption specific surface area of ​​carbon black was determined according to ASTM D4820-93.

[0180] From the perspective of rubber rigidity, the dibutyl phthalate (DBP) absorption of carbon black is preferably 50 ml / 100g or more, more preferably 100 ml / 100g or more. On the other hand, from the perspective of adaptability to rubber deformation, it is preferably 250 ml / 100g or less, more preferably 150 ml / 100g or less. It should be noted that the DBP absorption of carbon black is measured according to ASTM D2414-93.

[0181] There are no particular limitations on carbon black; examples include furnace blacks such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black; thermal blacks such as FT and MT; and channel blacks such as EPC, MPC, and CC. Additionally, as part numbers, examples include N134, N110, N220, N234, N219, N339, N330, N326, N351, N550, and N762. These can be used individually or in combination with two or more.

[0182] Besides mineral oil, carbon black can also be made from biomass materials such as lignin and vegetable oil, or from recycled materials such as pyrolysis oil obtained by pyrolyzing waste tires and other rubber products. From an environmental protection perspective, sustainable carbon black, such as biomass carbon black made from biomass materials and recycled carbon black made from recycled materials such as old products or waste, is more suitable.

[0183] In addition, carbon black can be manufactured by combustion in a furnace, by hydrothermal carbonization (HTC), or by pyrolysis of methane based on thermal cracking carbon black methods.

[0184] As commercially available products, those from Asahi Carbon Co., Ltd., Cabot Japan Co., Ltd., Tokai Carbon Co., Ltd., Mitsubishi Chemical Co., Ltd., LION Co., Ltd., Nippon Steel Carbon Co., Ltd., Columbian Carbon Co., Ltd., etc. can be used. They can be used individually or in combination of two or more.

[0185] The carbon black content relative to 100 parts by weight of the rubber component is preferably 5 parts by weight or more, more preferably 10 parts by weight or more. As an upper limit, it is preferably 25 parts by weight or less, more preferably 20 parts by weight or less.

[0186] (iv) Other fillers

[0187] In addition to the aforementioned carbon black and silica, the crown rubber composition may further contain fillers commonly used in the tire industry, such as graphite, calcium carbonate, talc, alumina, clay, aluminum hydroxide, mica, and magnesium sulfate. Their content relative to 100 parts by weight of the rubber component is, for example, more than 0.1 parts by weight and less than 150 parts by weight.

[0188] (②) Plasticizer (softener) components

[0189] From the perspective of imparting plasticity to the rubber components during mixing and properly dispersing the powder material, a softener (plasticizer) component is preferably used in the crown rubber composition as needed. It should be noted that the softener component here refers to both a softener that is liquid at 25°C and a softener that is solid at 25°C.

[0190] Examples of plasticizers include resin components, oils, liquid polymers, and ester-based plasticizers. These plasticizers can be derived from mineral resources such as petroleum or natural gas, from biomass, or from naphtha recycled from rubber or non-rubber products. Alternatively, low-molecular-weight hydrocarbon components obtained through the pyrolysis and extraction of used tires or products containing various components can also be used as plasticizers; plasticizers derived from biomass or from recycling are preferred as sustainable plasticizers.

[0191] It should be noted that these softeners can be used alone or in combination of two or more. The content of the softener component relative to 100 parts by weight of the rubber component is preferably 45 parts by weight or more, more preferably 50 parts by weight or more. As an upper limit, it is preferably 90 parts by weight or less, more preferably 85 parts by weight or less. It should be noted that the content of the softener component also includes the amount of oil contained in the rubber (oil-extended rubber), etc.

[0192] (i)Oil

[0193] Examples of oils include mineral oil, vegetable oil, and animal oil. Additionally, from a life cycle assessment perspective, oil refined from waste oil used in rubber mixers or engines, or waste cooking oil used in restaurants, can also be used.

[0194] (i-1) mineral oil

[0195] In this specification, mineral oil refers to oil derived from mineral resources such as petroleum and natural gas. Examples of mineral oils include alkane-based oils, cycloalkane-based oils, and aromatic oils.

[0196] Specific examples of mineral oils include MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), and RAE (Residual Aromatic Extract).

[0197] Alternatively, for environmental reasons, oils with low polycyclic aromatic compounds (PCA) content can be used. Examples of such low PCA content oils include MES, TDAE, and heavy cycloalkane oils.

[0198] Commercially available mineral oils include, for example, alkane-based, aromatic, and cycloalkane-based oils. Products from companies such as Idemitsu Kosan Co., Ltd., Sankyo Oil & Chemical Co., Ltd., ENEOS Co., Ltd., OLISOY Corporation, H&R Corporation, Toyokuni Oil Co., Ltd., Showa Shell Oil Co., Ltd., and Fuji Kosan Co., Ltd. can be used. These can be used alone or in combination of two or more.

[0199] (i-2) Vegetable oils

[0200] Examples of vegetable oils include flaxseed oil, rapeseed oil, safflower oil, soybean oil, corn oil, cottonseed oil, rice bran oil, tall oil, sesame oil, fragrant oil, castor oil, tung oil, pine oil, pine tar, sunflower seed oil, coconut oil, palm oil, palm kernel oil, olive oil, camellia oil, jojoba oil, macadamia nut oil, peanut oil, grapeseed oil, and wood wax.

[0201] In addition, examples of vegetable oils include refined oils (such as salad oil) refined from the aforementioned oils, transesterified oils, hydrogenated solidified oils, thermally polymerized oils, oxidized polymerized oils, and waste edible oils recycled after use as cooking oils. 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 with two or more.

[0202] As a vegetable oil, it is preferable to contain acylglycerols, and more preferably 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 the type of acylglycerol; it can be 1-monoacylglycerol, 2-monoacylglycerol, 1,2-diacylglycerol, 1,3-diacylglycerol, or triacylglycerol. Furthermore, acylglycerols can be monomers, dimers, or polymers of trimer or higher. It should be noted that acylglycerols of dimer or higher form can be obtained through thermal polymerization or oxidative polymerization. Additionally, acylglycerols can be liquid or solid at room temperature (25°C).

[0203] There are no particular limitations on the method for confirming whether a rubber composition contains acylglycerol; it can be done by... 1 Confirmation is achieved by ¹H-NMR determination. For example, a rubber composition mixed with triacylglycerol is impregnated in deuterated chloroform at room temperature (25°C) for 24 hours, and after removing the rubber composition, the concentration is determined at room temperature. 1 H-NMR, with the tetramethylsilane (TMS) signal set to 0.00 ppm, observed signals around 5.26 ppm, 4.28 ppm, and 4.15 ppm. It is speculated that these signals originate from hydrogen atoms bonded to the carbon atom adjacent to the oxygen atom of the ester group, thus confirming the presence of acylglycerol. It should be noted that "around" here refers to a range of ±0.10 ppm.

[0204] It should be noted that, as a fatty acid, there are no particular limitations; it can be either unsaturated or saturated fatty acids. Examples of unsaturated fatty acids include monounsaturated fatty acids such as oleic acid, and polyunsaturated fatty acids such as linoleic acid and linolenic acid. Examples of saturated fatty acids include butyric acid and lauric acid.

[0205] Among these, fatty acids with fewer double bonds are preferred, namely saturated fatty acids or monounsaturated fatty acids, with oleic acid being the most preferred. Vegetable oils containing such fatty acids can be, for example, vegetable oils containing saturated or monounsaturated fatty acids, or vegetable oils that have undergone transesterification or other modifications. Furthermore, to produce vegetable oils containing such fatty acids, plants can be improved through variety improvement, gene recombination, genome editing, or other methods.

[0206] As for vegetable oils, commercially available vegetable oils can be used, such as those from Idemitsu Kosan Co., Ltd., Sankyo Oil & Chemical Co., Ltd., ENEOS Co., Ltd., OLISOY Co., Ltd., H&R Co., Ltd., Toyokuni Oil Co., Ltd., Fuji Kosan Co., Ltd., Nissin Oliyo Group Co., Ltd., etc.

[0207] (ii) Liquid rubber

[0208] Liquid rubber refers to polymers that are liquid at room temperature (25°C) and are rubber components that can be extracted from vulcanized tires using acetone extraction. Examples of liquid rubber include farnesene polymers, liquid diene polymers, and their hydrides.

[0209] Farnese polymers are polymers obtained by polymerizing farnese and have structural units based on farnese. Farnese contains isomers such as α-farnese ((3E,7E)-3,7,11-trimethyl-1,3,6,10-dodecathetene) and β-farnese (7,11-dimethyl-3-methylene-1,6,10-dodecathetene).

[0210] Farnese polymers can be homopolymers of farnese (farnese homopolymers) or copolymers of farnese and vinyl monomers (farnese-vinyl monomer copolymers).

[0211] Examples of liquid diene polymers include liquid styrene-butadiene copolymer (liquid SBR), liquid butadiene polymer (liquid BR), liquid isoprene polymer (liquid IR), and liquid styrene-isoprene copolymer (liquid SIR).

[0212] The weight-average molecular weight (Mw) of polystyrene-based liquid diene polymers, as determined by gel permeation chromatography (GPC), is, for example, greater than 1.0 × 10⁻⁶. 3 And less than 2.0 × 10 5 Here, the Mw of the liquid diene polymer is the polystyrene equivalent determined by gel permeation chromatography (GPC).

[0213] As a liquid rubber, products from companies such as KURARAY Co., Ltd. and Cray Valley Co., Ltd. can be used.

[0214] (iii) Resin composition

[0215] The tread rubber composition preferably contains a resin component. By including a resin component in the rubber composition, the adhesive properties of the resin component improve the contact with the road surface, thus it is believed that further improvements in handling stability at high speeds can be achieved.

[0216] The resin component also functions as an adhesive agent. It can be solid or liquid at room temperature. Specific resin components include, for example, rosin-based resins, styrene-based resins, benzofuran-based resins, terpene-based resins, C5 resins, C9 resins, C5C9 resins, and acrylic resins; two or more can be used in combination. It should be noted that these resin components can also be endowed with modifying groups capable of reacting with silica, etc., as needed. Furthermore, the content relative to 100 parts by weight of the rubber component is preferably 10 parts by weight or more, more preferably 20 parts by weight or more. As an upper limit, it is preferably 60 parts by weight or less, more preferably 50 parts by weight or less.

[0217] Rosin-based resins are resins obtained by processing rosin, with rosin acid as the main component. These rosin-based resins (rosin derivatives) can be classified according to whether they have been modified or not, into unmodified rosin and modified rosin derivatives. Examples of unmodified rosin include tall oil rosin, resin rosin, wood rosin, disproportionated rosin, polymerized rosin, hydrogenated rosin, and other chemically modified rosin. Modified rosin derivatives are modifications of unmodified rosin, including rosin esters, unsaturated carboxylic acid-modified rosin derivatives, unsaturated carboxylic acid-modified rosin esters, rosin amide compounds, and rosin amine salts.

[0218] Styrene-based resins are polymers that use styrene-based monomers as constituent monomers. Examples include polymers formed by polymerizing styrene-based monomers as the main component (50% by mass or more). 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.), copolymers obtained by copolymerizing two or more styrene-based monomers, copolymers of styrene-based monomers and other monomers that can be copolymerized with them can also be cited.

[0219] Other monomers mentioned above may include acrylonitrile, methacrylonitrile and other acrylonitrile derivatives; acrylic acid derivatives, methacrylic acid and other unsaturated carboxylic acids; methyl acrylate, methyl methacrylate and other unsaturated carboxylic acid esters; dienes such as chloroprene, butadiene, isoprene and other dienes; alkenes such as 1-butene, 1-pentene; α,β-unsaturated carboxylic acids or their anhydrides such as maleic anhydride; etc.

[0220] Among benzofuran-based resins, benzofuran-indene resin is preferred. Benzofuran-indene resin is a resin containing benzofuran and indene as monomeric components constituting the resin's backbone (main chain). Examples of monomeric components in the backbone other than benzofuran and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

[0221] The hydroxyl value (OH value) of benzofuran indene resin is, for example, greater than 15 mg KOH / g and less than 150 mg KOH / g. It should be noted that the OH value refers to the amount of potassium hydroxide required, expressed in milligrams, to neutralize the acetic acid bonded to the hydroxyl group when 1 g of resin is acetylated, and is determined by potentiometric titration (JIS K 0070:1992).

[0222] The softening point of benzofuran indene resin is, for example, above 30°C and below 160°C. It should be noted that the softening point is determined using a ring-and-ball softening point tester, as specified in JIS K 6220-1:2001, and is the temperature at which the ball drops.

[0223] Examples of terpene-based resins include polyterpenes, terpene phenols, and aromatic modified terpene resins. Polyterpenes are resins obtained by polymerizing terpene compounds and their hydrides. Terpene compounds are composed of (C5H8) resins. n The composition of hydrocarbons and their oxygen-containing derivatives is represented by the class of monoterpenes (C64- ... 10 H 16 ), sesquiterpenes (C 15 H 24 ), diterpenes (C 20 H 32 Compounds with terpenes as their basic skeleton include, for example, α-pinene, β-pinene, dipentene, limonene, myrcene, allocirrhene, ocimene, α-phellandrene, α-terpinene, γ-terpinene, terpinene oil, 1,8-cineole, 1,4-cineole, α-terpineol, β-terpineol, and γ-terpineol.

[0224] As polyterpenes, in addition to terpene resins such as α-pinene resin, β-pinene resin, limonene resin, dipentene resin, and β-pinene / limonene resin, which are made from the aforementioned terpene compounds, hydrogenated terpene resins that have undergone hydrogenation treatment can also be cited. As terpene phenols, resins copolymerized with the aforementioned terpene compounds and phenolic compounds, as well as resins that have undergone hydrogenation treatment, can be cited. Specifically, resins formed by condensing the aforementioned terpene compounds, phenolic compounds, and formaldehyde can be cited. It should be noted that phenolic compounds include, for example, phenol, bisphenol A, cresol, and xylenol. As aromatic modified terpene resins, resins obtained by modifying terpene resins with aromatic compounds, as well as resins that have undergone hydrogenation treatment, can be cited. It should be noted that, as aromatic compounds, there are no particular limitations as long as they have an aromatic ring. Examples include phenols such as phenol, alkylphenols, alkoxyphenols, and phenols containing unsaturated hydrocarbon groups; naphthols such as naphthols, alkylnaphthols, alkoxynaphthols, and naphthols containing unsaturated hydrocarbon groups; styrene derivatives such as styrene, alkylstyrene, alkoxystyrene, and styrene containing unsaturated hydrocarbon groups; benzofurans, indene, etc.

[0225] "C5 resin" refers to resin obtained by polymerizing C5 fractions. Examples of C5 fractions include petroleum fractions with 4 to 5 carbon atoms, such as cyclopentadiene, pentene, pentadiene, and isoprene. Dicyclopentadiene resin (DCPD resin) is a suitable C5-based petroleum resin.

[0226] "C9 resin" refers to a resin obtained by polymerizing C9 fractions, or a resin obtained by hydrogenation or modification of C9 fractions. Examples of C9 fractions include petroleum fractions with 8 to 10 carbon atoms, such as vinyltoluene, alkylstyrene, indene, and methylindene. Specific examples include benzofuran-indene resin, benzofuran resin, indene resin, and aromatic vinyl resins. As aromatic vinyl resins, α-methylstyrene (AMS resin) or homopolymers of styrene or copolymers of α-methylstyrene and styrene are preferred for economic reasons, ease of processing, and excellent heat dissipation; copolymers of α-methylstyrene and styrene are more preferred. Commercially available aromatic vinyl resins, such as those from KRATON and Eastman Chemical, can be used.

[0227] "C5C9 resin" refers to a resin obtained by copolymerizing the aforementioned C5 fraction and C9 fraction, or it can be a resin obtained by hydrogenation or modification of these fractions. Examples of C5 and C9 fractions include the aforementioned petroleum fractions. As the C5C9 resin, commercially available resins such as those from Tosoh Corporation and Luhua Corporation can be used.

[0228] There are no particular limitations on the acrylic resin; for example, solvent-free acrylic resins can be used.

[0229] Solvent-free acrylic resins include (meth)acrylic resins (polymers) synthesized via high-temperature continuous polymerization (high-temperature continuous bulk polymerization) without using polymerization initiators, chain transfer agents, organic solvents, etc., as byproducts (as described in US Patent No. 4,414,370, Japanese Patent Application Publication No. 59-6207, Japanese Patent Application Publication No. 5-58005, Japanese Patent Application Publication No. 1-313522, US Patent No. 5,010,166, and the Toa Synthetic Research Yearbook TREND2000 No. 3, pp. 42-45). It should be noted that in this invention, (meth)acrylic acid refers to both methacrylic acid and acrylic acid.

[0230] Examples of monomeric components constituting the above-mentioned acrylic resins include (meth)acrylic acid, (meth)acrylates (alkyl esters, aryl esters, aralkyl esters, etc.), (meth)acrylamide, and (meth)acrylamide derivatives.

[0231] In addition, as a monomer component constituting the above-mentioned acrylic resin, aromatic vinyl monomers such as styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, and divinylnaphthalene can be used together with (meth)acrylic acid or (meth)acrylic acid derivatives.

[0232] The aforementioned acrylic resins can be resins composed solely of (meth)acrylic acid, or resins that incorporate components other than (meth)acrylic acid as constituent elements. Furthermore, the aforementioned acrylic resins may contain hydroxyl, carboxyl, or silanol groups, etc.

[0233] As a resin component, products from companies such as Maruzen Petrochemical Co., Ltd., Sumitomo Bakelite Co., Ltd., Yasuhara Chemical Co., Ltd., Tosoh Co., Ltd., Rutgers Chemicals Co., Ltd., BASF Corporation, KRATON Corporation, Nippon Paint Co., Ltd., Nippon Shokubai Co., Ltd., ENEOS Co., Ltd., Arakawa Chemical Industry Co., Ltd., Taoka Chemical Industry Co., Ltd., etc. can be used.

[0234] (③) Wax

[0235] The crown rubber composition may contain wax. The wax content relative to 100 parts by weight of the rubber component is preferably 0.5 parts by weight or more, more preferably 1.0 parts by weight or more, and even more preferably 1.5 parts by weight or more. As an upper limit, it is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, and even more preferably 10 parts by weight or less.

[0236] As for waxes, there are no particular limitations; any wax commonly used in the tire industry is suitable. Examples include mineral-based waxes and plant-derived waxes. Mineral-based waxes refer to waxes derived from mineral resources such as oil and natural gas. Plant-derived waxes refer to waxes derived from natural resources such as plants. Among these, mineral-based waxes are preferred.

[0237] Examples of plant-derived waxes include rice bran wax, carnauba wax, and candelilla wax. Examples of mineral-based waxes include paraffin wax, microcrystalline wax, and selected special waxes thereof, with paraffin wax being preferred. It should be noted that the waxes in this invention do not contain stearic acid.

[0238] It should be noted that, as a wax, commercially available waxes such as those from Ouchi Shinshin Chemical Industry Co., Ltd., Nippon Seiwa Co., Ltd., and Paramelt Co., Ltd. can be used. These waxes can be used alone or in combination of two or more.

[0239] (④) Anti-aging agents

[0240] The crown rubber composition may contain an anti-aging agent. The content of the anti-aging agent is, for example, more than 1 part by weight and less than 10 parts by weight per 100 parts by weight of the rubber component.

[0241] There are no particular limitations on anti-aging agents; examples include naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; diphenylamine-based anti-aging agents such as octyl diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; 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), and N,N'-xylyl-p-phenylenediamine. Anti-aging agents include p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and N,N'-di-2-naphthyl-p-phenylenediamine (DNPD); quinoline-based anti-aging agents such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based anti-aging agents such as 2,6-di-tert-butyl-4-methylphenol and styrylated phenol; and bisphenol-based, triphenol-based, and polyphenol-based anti-aging agents such as tetra-[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane. Among these, p-phenylenediamine-based and quinoline-based anti-aging agents are preferred, with polymers of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 2,2,4-trimethyl-1,2-dihydroquinoline being more preferred. These agents can be used alone or in combination of two or more.

[0242] As commercially available products, you can use products from companies such as Seiko Chemical Co., Ltd., Sumitomo Chemical Co., Ltd., Ouchi Shinsei Chemical Co., Ltd., and Flexis.

[0243] (⑤) Processing aids

[0244] The crown rubber composition may contain processing aids. Examples of processing aids include metal salts (compounds in which the hydrogen atoms of an acid are replaced by metal ions), fatty amides, amide esters, and fatty acid esters. They may be used alone or in combination of two or more. Among these, metal salts and fatty amides are preferred, and metal salts are more preferred.

[0245] Metals used in metal salts include alkali metals such as potassium and sodium, and alkaline earth metals such as calcium and barium. Magnesium, zinc, nickel, and molybdenum can also be used. Alkali metals are preferred.

[0246] Examples of acids used as metal salts include fatty acids such as lauric acid, myristic acid, and palmitic acid. Other acids that can be used include boric acid, carbonic acid, hydrochloric acid, nitric acid, and sulfuric acid.

[0247] Commercially available processing aids include products from Kishida Chemical Co., Ltd., Kenei Pharmaceutical Co., Ltd., Struktol Co., Ltd., and Performance Additives Co., Ltd.

[0248] The content of processing aids relative to 100 parts by weight of rubber component is preferably 1 part by weight or more, more preferably 2 parts by weight or more. As an upper limit, it is preferably 6 parts by weight or less, more preferably 4 parts by weight or less.

[0249] (⑥) Lubricant (stearic acid)

[0250] The crown rubber composition may contain a lubricant. Preferably, a lubricant based on fatty acid derivatives such as stearic acid is used. As stearic acid, existing known stearic acid can be used; specifically, products from companies such as Nippon Yu Corporation, NOF Corporation, Kao Corporation, Fujifilm, Kojun Pharmaceutical Co., Ltd., and Chiba Fatty Acid Co., Ltd. can be used. Alternatively, Struktol WB16 manufactured by Struktol Corporation can also be used.

[0251] The content of stearic acid relative to 100 parts by weight of the rubber component is preferably more than 0.5 parts by weight and less than 10.0 parts by weight.

[0252] (⑦) Zinc oxide

[0253] The crown rubber composition may contain zinc oxide. The content of zinc oxide is, for example, more than 0.5 parts by weight and less than 10 parts by weight per 100 parts by weight of the rubber component. As zinc oxide, existing known zinc oxides can be used, such as products from Mitsui Metal Mining Co., Ltd., Toho Zinc Co., Ltd., HAKUSUI TECH Co., Ltd., Seido Chemical Industry Co., Ltd., Sakai Chemical Industry Co., Ltd., etc.

[0254] (⑧) Crosslinking agents and vulcanization accelerators

[0255] The crown rubber composition preferably contains a crosslinking agent such as sulfur. The content of the crosslinking agent is, for example, more than 0.1 parts by weight and less than 10.0 parts by weight per 100 parts by weight of the rubber component. It should be noted that the sulfur content is the amount of pure sulfur, or, in the case of using insoluble sulfur, the content after removing oil.

[0256] Examples of sulfur compounds commonly used in the rubber industry include powdered sulfur, settled sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, and soluble sulfur. These can be used individually or in combination of two or more.

[0257] It should be noted that, as sulfur, products from companies such as Tsurumi Chemical Industry Co., Ltd., Karuizawa Sulfur Co., Ltd., Shikoku Chemical Industry Co., Ltd., Flexis Co., Ltd., Nippon Kanryu Kogyo Co., Ltd., and Hosoi Chemical Industry Co., Ltd. can be used.

[0258] Crosslinking agents other than sulfur can also be used. Specifically, sulfur-containing vulcanizing agents such as TACKROL V200 manufactured by Taoka Chemical Industry Co., Ltd., DURALINK HTS (1,6-hexamethylene-dithiosulfate sodium dihydrate) manufactured by Flexis, and KA9188 (1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane: hybrid crosslinking agent) manufactured by LANXESS, as well as organic peroxides such as dicumyl peroxide, can be used.

[0259] Furthermore, the crown rubber composition preferably contains a vulcanization accelerator. The content of the vulcanization accelerator relative to 100 parts by weight of the rubber component is, for example, more than 0.3 parts by weight and less than 10.0 parts by weight.

[0260] Examples of vulcanization accelerators include thiazole-based accelerators such as 2-mercaptobenzothiazole, di-2-benzothiazole disulfide, and N-cyclohexyl-2-benzothiazole sulfenamide; thiuram-based accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetra(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, N-ethylene oxide-2-benzothiazole sulfenamide, N,N'-diisopropyl-2-benzothiazole sulfenamide; and guanidine-based accelerators such as diphenylguanidine, di-o-tolylguanidine, and o-tolylbiguanidine. These accelerators can be used alone or in combination of two or more.

[0261] (⑨) Other

[0262] In addition to the components mentioned above, the crown rubber composition may also be formulated with additives commonly used in the tire industry, such as organic fillers like cellulose fibers and organic peroxides, as needed. The content of these additives relative to 100 parts by weight of the rubber component is, for example, more than 0.1 parts by weight and less than 50 parts by weight.

[0263] It should be noted that, in this invention, the various materials containing carbon atoms (e.g., 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 mixture of this invention from carbon dioxide, carbon dioxide can be directly converted, or methane obtained through a methanation process of synthesizing methane from carbon dioxide can be converted.

[0264] (2) Preparation of crown rubber composition

[0265] The crown rubber composition can be manufactured by a general method, such as a basic mixing process including a compounded rubber component and a filler such as silica, and a refining mixing process of the compound obtained in the basic mixing process and a crosslinking agent.

[0266] Mixing can be carried out using well-known (closed) mixing machines such as Banbury mixers, kneaders, and open mills.

[0267] The mixing temperature in the basic mixing process is, for example, above 50°C and below 200°C, and the mixing time is, for example, above 30 seconds and below 30 minutes. In addition to the above-mentioned components, in the basic mixing process, appropriate compounding agents used in the existing rubber industry may also be added as needed, such as softeners like oils, stearic acid, zinc oxide, anti-aging agents, waxes, vulcanization accelerators, etc., and then mixed.

[0268] In the refining and mixing process, the mixture obtained in the basic mixing process and the crosslinking agent are mixed together. The mixing temperature in the refining and mixing process is, for example, above room temperature but below 80°C, and the mixing time is, for example, above 1 minute but below 15 minutes. In addition to the above-mentioned components, in the refining and mixing process, vulcanization accelerators, zinc oxide, etc., may also be added as needed and mixed together.

[0269] The crown rubber composition obtained above is then extruded and processed into a specified shape, thereby forming a tire tread.

[0270] 3. Tire manufacturing

[0271] The tire of this embodiment can be manufactured using conventional methods. First, the tread is manufactured by molding the crown rubber composition obtained above into a predetermined shape. Next, it is assembled with other rubber components on a tire forming machine to produce an uncured tire.

[0272] It should be noted that, when the tread layer is made into a multi-layered structure with the base rubber layer, the aforementioned rubber components and compounding materials can be used essentially, with appropriate variations in their mixing ratios, and the mixture can be compounded in the same way to obtain a rubber composition (base rubber composition) that forms the base rubber layer. Furthermore, the tread rubber, extruded together with the crown rubber layer to form a tread rubber of a specified shape, is then molded together with other tire components on a tire forming machine using conventional methods, thereby producing a tire in the form of an uncured tire.

[0273] Specifically, on the forming drum, the inner liner layer, which serves as a component to ensure the airtightness of the tire, the tire carcass, which serves as a component to bear the load, impact, and air pressure borne by the tire, the belt layer component, which serves as a component to strongly clamp the tire carcass and improve the tread rigidity, and the crown belt layer are wound together. While fixing the two ends of the tire carcass at both sides, a bead portion, which serves as a component to fix the tire to the rim, is arranged. After being formed into a ring shape, the tread is attached to the center of the outer periphery to form the tread portion, and the tire sidewall is attached to the radially outer side to form the sidewall portion, thereby producing an uncured tire.

[0274] Then, the uncured tires prepared above are heated and pressurized in a vulcanizing machine to obtain a tire. The vulcanization process can be carried out using known vulcanization methods. For example, the vulcanization temperature is above 120°C and below 200°C, and the vulcanization time is above 5 minutes and below 15 minutes.

[0275] As described above, the complex elastic modulus of the crown rubber layer and the thickness of the center of the tread layer are appropriately controlled, thus enabling a further improvement in the handling stability of tires using sustainable cords in the carcass ply layer at high speeds.

[0276] Furthermore, the tires of this invention are not particularly limited in type and can be used as tires for passenger cars, large passenger cars, large SUVs, trucks / buses, two-wheeled vehicles, racing tires, studless anti-skid tires (winter tires), all-season tires, run-flat tires, aircraft tires, mining tires, non-pneumatic tires, etc., with passenger car tires being the preferred option. Additionally, pneumatic tires are preferred.

[0277] Example

[0278] The following are examples (embodiments) that are considered preferred in practice, but the scope of the invention is not limited to these embodiments.

[0279] The handling stability performance of tires (tire size: 225 / 55R16, land ratio: 85%) consisting of various carcasses, treads and other rubber components shown below was studied, and the results are shown in the lower part of Tables 1 and 2.

[0280] 1. Manufacturing of the crown rubber composition

[0281] Crown rubber compositions are prepared using the various compounded materials shown below.

[0282] (1) Mixed materials

[0283] (a) Rubber composition

[0284] (①)NR: TSR20

[0285] (②)SBR-1: Modified S-SBR obtained by the method shown in the following paragraph.

[0286] (Styrene content: 25% by mass, Vinyl content: 27% by mass)

[0287] (③)SBR-2: SLR6430 (S-SBR) manufactured by Trinseo.

[0288] (Styrene content: 40% by mass, vinyl content: 24% by mass, 37.5% oil-extended)

[0289] (④) SBR-3: HPR840 (S-SBR) manufactured by ENEOS Materials.

[0290] (Styrene content: 10% by mass, Vinyl content: 42% by mass)

[0291] (⑤) BR: Ubepol BR150B (high cis BR) manufactured by Ube Industries, Ltd.

[0292] (cis content 97% by mass, trans content 2% by mass, vinyl content 1% by mass)

[0293] (Manufacturing of SBR-1)

[0294] The SBR-1 described above was prepared according to the following steps. First, two high-pressure reactors with an internal volume of 10L, an inlet at the bottom, an outlet at the head, and equipped with a stirrer and a jacket were connected in series. Butadiene, styrene, and cyclohexane were mixed in a specified ratio. This mixture was then passed through a dehydration column filled with activated alumina. To remove impurities, n-butyllithium was mixed in a static mixer and continuously supplied from the bottom of the first reactor. 2,2-bis(2-oxacyclopentyl)propane (as a polar substance) and n-butyllithium (as a polymerization initiator) were then continuously supplied from the bottom of the first reactor at a specified rate, maintaining the reactor temperature at 95°C. The polymer solution was continuously discharged from the head of the reactor and supplied to the second reactor. The temperature of the second reactor was maintained at 95°C. A mixture of tetraglycidyl-1,3-diaminomethylcyclohexane (monomer) as a modifier and the oligomer components was continuously added at a prescribed rate in the form of a 1000-fold diluted cyclohexane solution to carry out the modification reaction. The polymer solution was continuously discharged from the reactor, and an antioxidant was continuously added using a static mixer. After removing the solvent, the modified diene polymer (SBR-1) was obtained as the target product.

[0295] (b) Compound materials other than rubber components

[0296] (①) Carbon black: Show Black N134 manufactured by Cabot Japan Co., Ltd.

[0297] (CTAB specific surface area: 135m²) 2 / g)

[0298] (②) Silica: Ultrasil VN3 manufactured by Evonik Industries

[0299] (N2SA: 175m) 2 / g, average particle size: 18nm)

[0300] (③) Oil: DIANA PROCESS AH-24 (fragrant oil) manufactured by Idemitsu Kosan Co., Ltd.

[0301] (④) Silane coupling agent: Si266 manufactured by Evonik Industries

[0302] (bis(3-triethoxysilylpropyl)disulfide)

[0303] (⑤) Resin: SYLVATRAXX4401 manufactured by Kraton Company

[0304] (α-Methylstyrene resin)

[0305] (⑥) Zinc oxide: Two types of zinc oxide manufactured by Mitsui Metals Mining Co., Ltd.

[0306] (⑦) Stearic acid: Beaded stearic acid "Camellia" manufactured by Nippon Oil Company.

[0307] (⑧) Wax: Sunnoc N, manufactured by Daichi Shinshin Chemical Industry Co., Ltd.

[0308] (9) Anti-aging agent-1: Antigen 6C manufactured by Sumitomo Chemical Co., Ltd.

[0309] (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine)

[0310] (⑩) Anti-aging agent-2: Antigen RD manufactured by Sumitomo Chemical Co., Ltd.

[0311] (Polymer of 2,2,4-trimethyl-1,2-dihydroquinoline)

[0312] Sulfur: Powdered sulfur (containing 5% oil) manufactured by Tsurumi Chemical Industry Co., Ltd.

[0313] Vulcanization Accelerator-1: NOCCELER CZ manufactured by Ouchi Shinshin Chemical Industry Co., Ltd.

[0314] (N-Cyclohexyl-2-benzothiazolylsulfonamide)(CBS)

[0315] Vulcanization accelerator-2: SOXINOL D (DPG) manufactured by Sumitomo Chemical Co., Ltd.

[0316] (N,N'-diphenylguanidine)

[0317] (2) Manufacturing of crown rubber composition

[0318] According to the mixing contents shown in Tables 1 and 2, use a Banbury mixer to mix the materials other than sulfur and vulcanization accelerator at 150°C for 5 minutes to obtain the mixture. It should be noted that each mixing amount is in parts by mass.

[0319] Next, sulfur and vulcanization accelerator are added to the mixture, and it is mixed for 5 minutes at 80°C using an open mill to obtain the rubber compositions for each crown.

[0320] 2. Manufacturing of the tread area

[0321] Using the crown rubber compositions obtained above and the separately prepared base rubber composition, the tread portion is manufactured by extrusion in a specified shape with the thickness A (mm) of the center portion of the tread portion as shown in Tables 1 and 2. The tread portion thickness is 80%.

[0322] 3. Manufacturing of the carcass ply

[0323] In addition, the tire cords of each ply are manufactured using the specifications shown in Tables 1 and 2, except for the ply cords of the same specifications. It should be noted that in Tables 1 and 2, PET (bio) refers to polyester cords manufactured using raw materials derived from biological sources, and PET (recycled) refers to recycled polyester cords recycled from plastic waste such as PET bottles or old clothes.

[0324] 4. Manufacturing of pneumatic tires

[0325] Then, it is bonded together with other tire components to form an uncured tire, and then vulcanized under pressure at 170°C for 10 minutes to manufacture the test tires of Examples 1 to 6 and Comparative Examples 1 to 3.

[0326] Next, rubber test pieces for viscoelasticity testing were prepared by cutting a piece from the crown rubber layer of the tread of each test tire, with the tire circumference as the long side. The piece was 20 mm long, 4 mm wide, and 1 mm thick. For each test piece, the complex elastic modulus E was determined using the "EPLEXOR" series manufactured by GABO under the conditions of 30°C, 10 Hz frequency, 5% initial strain, and 1% dynamic strain, in the deformation mode: elongation. * (MPa).

[0327] It should be noted that the thickness direction of the sample is the tire radius direction. It should also be noted that when the same proportion is used in multiple embodiments, the values ​​are the average of those measured from each test tire.

[0328] 5. Parameters

[0329] Then, calculate (E) * / A), ((E) * / A)×D) and ((E * / A)×D×(100-IF)).

[0330] 6. Performance Evaluation (Evaluation of handling stability performance at high speeds)

[0331] All test tires were installed on all wheels of a domestically produced FR car (2000cc engine), and inflated with air to achieve an internal pressure of 250 kPa (the standard internal pressure for passenger cars). After a break-in period on a test route with a road surface temperature of 25°C and dry asphalt, the vehicle was driven at approximately 120 km / h to conduct a comprehensive sensory evaluation of steering control stability (steering wheel responsiveness to small steering angle changes, responsiveness to sudden lane changes, etc.). In the evaluation, 10 drivers provided feedback on a 5-point scale (higher values ​​are better), and the total score for each driver's evaluation was calculated.

[0332] Next, the result from Comparative Example 1 was set to 100 and exponentialized based on the following formula to evaluate the handling stability performance at high speeds. The larger the value, the better the handling stability performance at high speeds.

[0333] Handling stability performance at high speed = [(Results of the test tires) / (Results of Comparative Example 1)] × 100 [Table 1]

[0334]

[0335] [Table 2]

[0336]

[0337] The present invention has been described above based on the embodiments, but the present invention is not limited to the embodiments described above. Various modifications can be made to the above embodiments within the same and equivalent scope as the present invention.

[0338] This invention (1) relates to a tire having a tread portion having a crown rubber layer and a carcass portion, characterized in that,

[0339] In the tire carcass ply that constitutes the aforementioned tire carcass portion, sustainable polyester cords are used as the ply cords.

[0340] The complex elastic modulus E of the aforementioned crown rubber layer was measured under the following conditions: temperature 30℃, initial strain 5%, dynamic strain 1%, frequency 10Hz, and deformation mode: elongation. * The thickness A (mm) of the center part of the tread area (MPa) and the thickness A (mm) of the tread area satisfy the following formula.

[0341] E * / A≥1.3

[0342] This invention (2) relates to the tire described in this invention (1), characterized in that the above (E) * / A) satisfies the following formula.

[0343] E * / A≥1.5

[0344] This invention (3) relates to the tire described in invention (1) or (2), characterized in that the number D (columns / 5cm) of the sustainable polyester cords present in the tread portion within a width of 5cm in a direction perpendicular to its length direction is the same as that of the tire described in invention (E). * The product of / A) ((E) * / A)×D) satisfies the following formula.

[0345] (E * / A)×D>39

[0346] This invention (4) relates to the tire described in this invention (3), characterized in that the above ((E) * / A)×D) satisfies the following formula.

[0347] (E * / A)×D≥50

[0348] The present invention (5) relates to tires in any combination with any of the present inventions (1) to (4), characterized in that the above-mentioned sustainable polyester cord is a sustainable polyethylene terephthalate cord.

[0349] The present invention (6) relates to tires in any combination with any of the present inventions (1) to (5), characterized in that the content of isophthalic acid in the above-mentioned sustainable polyester cord is less than 0.1 mol%.

[0350] This invention (7) relates to the tire described in this invention (6), characterized in that the isophthalic acid content in the above-mentioned sustainable polyester cord is 0.0 mol%.

[0351] The present invention (8) relates to a tire in any combination with any of the present inventions (1) to (7), characterized in that the above (E) * / A) The number D (columns / 5cm) of the sustainable polyester cords present in the above tire tread in a 5cm width in a direction perpendicular to its length direction, and the isophthalic acid content IF (%) in the above sustainable polyester cords satisfy the following formula.

[0352] (E * / A)×D×(100-IF)>5000

[0353] The present invention (9) relates to a tire in any combination with any of the present inventions (1) to (8), characterized in that the strength S (cN / dtex) of the aforementioned sustainable polyester cord is 6.0 cN / dtex or more.

[0354] The present invention (10) relates to a tire in any combination of any of the present inventions (1) to (9), characterized in that the product (S×D) of the strength S (cN / dtex) of the sustainable polyester cord and the number D (cords / 5cm) of the sustainable polyester cord in the tread portion within a width of 5cm in a direction perpendicular to its length direction satisfies the following formula.

[0355] S×D≥160

[0356] The present invention (11) relates to the tire described in the present invention (10), characterized in that the above (S×D) satisfies the following formula.

[0357] S×D≥200

[0358] The present invention (12) relates to a tire in any combination of any of the present inventions (1) to (11), characterized in that the intermediate elongation E (%) of the sustainable polyester cord under a specified load L (cN / dtex) satisfies the following formula between the number D (cords / 5cm) of the sustainable polyester cord in the tread portion within a width of 5cm in a direction perpendicular to its length direction.

[0359] 12≤L×D / E≤20

[0360] The present invention (13) relates to the tire described in the present invention (12), characterized in that the above (L×D / E) satisfies the following formula.

[0361] 13.5 ≤ L × D / E ≤ 18.5

[0362] The present invention (14) relates to tires in any combination with any of the present inventions (1) to (13), characterized in that the breaking elongation of the aforementioned sustainable polyester cord is 10% or more.

[0363] The present invention (15) relates to tires in any combination with any of the present inventions (1) to (14), characterized in that the moisture heat resistance strength retention rate of the above-mentioned sustainable polyester cord is 80% or more.

[0364] Symbol Explanation

[0365] 1 tire

[0366] Second pregnancy face

[0367] 3rd tire side

[0368] 4 tire bead area

[0369] 5-Tire Bead

[0370] 6 fetuses

[0371] 6A carcass ply

[0372] 6a Inner Main Body

[0373] 6b Outer foldback

[0374] 7-band layer

[0375] 8 tire bead triangle

[0376] C centerline

Claims

1. A tire comprising a tread portion having a crown rubber layer and a carcass portion, characterized in that, In the tire carcass ply that constitutes the tire carcass portion, sustainable polyester cords are used as the ply cords. The complex elastic modulus E of the crown rubber layer was measured under the following conditions: temperature 30°C, initial strain 5%, dynamic strain 1%, frequency 10Hz, and deformation mode: elongation. * The thickness A of the center portion of the tread portion satisfies the following formula, wherein the complex elastic modulus E * The unit is MPa, and the unit of the thickness A is mm. AND * / A≥1.3。 2. The tire according to claim 1, characterized in that, The E * / A satisfies the following formula. AND * / A≥1.5。 3. The tire according to claim 1 or 2, characterized in that, The number D of the sustainable polyester cords present in the tread portion within a 5cm width perpendicular to its length direction and the number E * / A product (E * / A)×D satisfies the following formula, where the unit of the number of roots D is roots / 5cm. (AND * / A)×D>39。 4. The tire according to claim 3, characterized in that, The (E) * / A)×D satisfies the following formula. (AND * / A)×D≥50。 5. The tire according to claim 1 or 2, characterized in that, The sustainable polyester cord is a sustainable polyethylene terephthalate cord.

6. The tire according to claim 1 or 2, characterized in that, The isophthalic acid content in the sustainable polyester cord is less than 0.1 mol%.

7. The tire according to claim 6, characterized in that, The sustainable polyester cord contains 0.0 mol% isophthalic acid.

8. The tire according to claim 1 or 2, characterized in that, The E * / A. The number D of the sustainable polyester cords present in the tread portion within a 5cm width perpendicular to its length direction, and the isophthalic acid content IF in the sustainable polyester cords satisfy the following formula, wherein the number D is expressed in cords / 5cm, and the content IF is expressed in %. (E * / A)×D×(100-IF)>5000。 9. The tire according to claim 1 or 2, characterized in that, The strength S of the sustainable polyester cord is above 6.0 cN / dtex, wherein the unit of strength S is cN / dtex.

10. The tire according to claim 1 or 2, characterized in that, The product S×D of the strength S of the sustainable polyester cord and the number D of the sustainable polyester cords present in the tread portion within a 5cm width perpendicular to its length direction satisfies the following formula, where the unit of the strength S is cN / dtex and the unit of the number D is cords / 5cm. S×D≥160.

11. The tire according to claim 10, characterized in that, The S×D satisfies the following formula. S×D≥200.

12. The tire according to claim 1 or 2, characterized in that, The following formula applies to the relationship between the intermediate elongation E of the sustainable polyester cord under a specified load L and the number D of the sustainable polyester cord in the tread portion within a 5cm width perpendicular to its length direction, where the specified load L is in cN / dtex, the intermediate elongation E is in %, the number D is in cords / 5cm, and 12 ≤ L × D / E ≤ 20.

13. The tire according to claim 12, characterized in that, The L×D / E satisfies the following formula. 13.5≤L×D / E≤18.

5.

14. The tire according to claim 1 or 2, characterized in that, The sustainable polyester cord has a breaking elongation of more than 10%.

15. The tire according to claim 1 or 2, characterized in that, The sustainable polyester cord retains more than 80% of its strength in terms of resistance to damp heat.

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