Sealant tires

Abstract

A sealant tire comprising a sealant layer on an inner circumferential surface thereof, wherein, when the cross-sectional width and the outer diameter of the sealant tire which is incorporated with a regular rim and is set to have an internal pressure of 250 kPa are respectively defined as Wt (mm) and Dt (mm), Wt and Dt satisfy formula (1), and the dynamic complex elastic modulus G* of the sealant layer is 0.50-3.50 kPa when being measured in compliance with ISO 13145 in an atmosphere at 100°C with a 100% strain at a frequency of 0.1 Hz.　Formula (1): 1600 ≤ (Dt2×π / 4) / Wt ≤ 2827.4

Description

[Technical Field]

[0001] The present disclosure relates to a self-sealing tire. [Background technology]

[0002] Patent Document 1 discloses a tire that improves fuel economy by increasing the tire's outer diameter relative to its contact patch width compared to conventional tires. However, such narrow, large-diameter tires have a problem in that the tire's contact patch area is small, making it difficult to ensure steering stability.

[0003] Patent Document 2 discloses a tire that uses a sealant material that has excellent tear sealing properties. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2012 / 176476 [Patent Document 2] International Publication No. 2017 / 094653 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide a self-sealing tire having improved overall performance in terms of handling stability and air sealing performance. [Means for solving the problem]

[0006] As a result of extensive investigation, it was discovered that the above problem can be solved by setting the dynamic complex modulus of the sealant layer within a predetermined range in a narrow, large-diameter tire whose tire section width and outer diameter satisfy predetermined requirements.

[0007] Specifically, the present disclosure relates to a self-sealing tire having a sealant layer on its inner circumferential surface, wherein when the self-sealing tire is mounted on a regular rim and the internal pressure is set to 250 kPa, Wt (mm) is the cross-sectional width of the self-sealing tire, and Dt (mm) is the outer diameter of the self-sealing tire, and the Wt and Dt satisfy the following formula (1), and the dynamic complex modulus G* of the self-sealing tire measured in accordance with ISO 13145 under conditions of an atmosphere at 100°C, 100% strain, and a frequency of 0.1 Hz is 0.50 to 3.50 kPa: 1600≦(Dt 2 ×π / 4) / Wt≦2827.4 (1) [Effects of the Invention]

[0008] According to the present disclosure, a self-sealing tire is provided that has improved overall performance in terms of handling stability and air sealing performance. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram schematically illustrating an example of a cross section of a self-sealing tire. DETAILED DESCRIPTION OF THE INVENTION

[0010] A tire that is one embodiment of the present disclosure is a self-sealing tire having a sealant layer on its inner circumferential surface, and when mounted on a regular rim and the internal pressure is set to 250 kPa, the cross-sectional width of the self-sealing tire is Wt (mm) and the outer diameter is Dt (mm), where Wt and Dt satisfy the following formula (1): The dynamic complex modulus G* of the sealant layer, measured in accordance with ISO 13145 under conditions of an atmosphere at 100°C, 100% strain, and a frequency of 0.1 Hz, is 0.50 to 3.50 kPa (preferably 0.55 to 3.20 kPa, more preferably 0.60 to 2.90 kPa, and even more preferably 0.65 to 2.70 kPa). 1600≦(Dt 2 ×π / 4) / Wt≦2827.4 (1)

[0011] In this disclosure, the tire section width Wt (mm), tire section height Ht (mm), and tire outer diameter Dt (mm) are measured when the tire is mounted on a standard rim, inflated to an internal pressure of 250 kPa or more, and under no load. The "tire section width" refers to the maximum width between the outer sidewall surfaces in the above-mentioned state, excluding any patterns or letters on the tire sidewalls. The tire section height Ht is the distance from the bottom of the bead portion to the outermost surface of the tread, and is half the difference between the tire's outer diameter and the nominal rim diameter.

[0012] "Genuine rim" refers to the rim specified for each tire by the standard system that includes the standard on which the tire is based, for example, standard rim for JATMA, "Design Rim" for TRA, and "Measuring Rim" for ETRTO. In the case of a tire size that is not specified in the above standard system, it refers to the narrowest rim among the smallest diameter rims that can be mounted on the tire and do not cause air leakage between the rim and tire.

[0013] The self-sealing tire of the present disclosure is shaped so that the area of ​​the tire when viewed from the side is larger than the tire's cross-sectional width within a predetermined range. This improves the heat dissipation performance of the sidewalls, enabling the tire to achieve sufficient fuel economy. Specifically, when the tire is mounted on a standard rim and the internal pressure is set to 250 kPa, the cross-sectional width Wt (mm) and the outer diameter Dt (mm) of the tire are characterized by satisfying the following formula (1): 1600≦(Dt 2 ×π / 4) / Wt≦2827.4 (1)

[0014] If the tire shape satisfies formula (1), the area (mm ) when viewed from the side of the tire is calculated based on the tire cross-sectional width Wt (mm). 2 ), i.e., [(Dt / 2) 2 ×π)=(Dt 2×π / 4)] is appropriately ensured, improving the heat dissipation performance of the side portion, thereby sufficiently reducing rolling resistance and achieving good fuel efficiency.

[0015] Here, as Dt increases, the value of formula (1) increases, and conversely, as Dt decreases, the value decreases. On the other hand, as Wt increases, the value of formula (1) decreases, and conversely, as Wt decreases, the value increases. Therefore, by focusing on this point and adjusting Dt and Wt, Dt and Wt can be adjusted so that they satisfy formula (1). The value of formula (1) is preferably 1963.4 or more, more preferably 2000 or more. The value of formula (1) is also preferably 2800 or less, more preferably 2700 or less, and even more preferably 2600 or less.

[0016] Specific examples of tire sizes that satisfy formula (1) include 125 / 65R19, 145 / 60R18, 145 / 60R19, 155 / 55R18, 155 / 55R19, 155 / 70R17, 155 / 70R19, 165 / 55R20, 165 / 55R21, 165 / 60R19, 165 / 65R19, 165 / 70R18, 175 / 55R19, 175 / 55R20, 175 / 55R22, 175 / 60R18, 185 / 55R19, 185 / 60R20, 195 / 50R20, 195 / 55R20, and 205 / 55R16.

[0017] However, when a tire with the above-described shape is manufactured, the centrifugal force during rolling increases, causing the tire radius to grow significantly. As a result, there is a concern that the contact pressure will become uneven and the handling stability will deteriorate. In particular, the wider the tire cross-sectional width Wt of the tire, the greater the difference between the contact pressure at the tread center and the contact pressure at the tread shoulder will tend to become, which is thought to be more likely to lead to a deterioration in handling stability.

[0018] Therefore, when the dynamic complex modulus G* of the sealant layer satisfies the above requirements, the resulting self-sealing tire has improved overall performance in terms of steering stability and air sealing performance. The reason for this is thought to be as follows, without intending to be bound by theory.

[0019] By providing a sealant layer with a dynamic complex modulus G* of 0.50 kPa or more, it is believed that handling stability can be improved by increasing the reaction force against torsion of the tire while maintaining the shape of the sealant layer. Also, by setting the dynamic complex modulus G* of the sealant layer to 3.50 kPa or less, the flowability of the sealant layer can be optimized, sealing tears and ensuring air sealing performance.

[0020] The self-sealing tire of the present disclosure preferably has a Dt / G* of 150 or more, more preferably 240 or more, even more preferably 330 or more, even more preferably 420 or more, and particularly preferably 500 or more. The sealant of the present disclosure has a large tire outer diameter and a small dynamic complex modulus, which raises concerns about a decrease in steering stability. Therefore, steering stability can be improved by reducing the tire outer diameter in accordance with the dynamic complex modulus. Furthermore, Dt / G* is preferably 1500 or less, more preferably 1300 or less, even more preferably 1100 or less, and particularly preferably 1000 or less.

[0021] The self-sealing tire of the present disclosure preferably has a Wt / G* of 400 or less, more preferably 320 or less, even more preferably 300 or less, and particularly preferably 280 or less. The self-sealing tire of the present disclosure has a small tire section width and a small dynamic complex modulus, which raises concerns about a decrease in steering stability. Therefore, steering stability can be improved by increasing the tire section width in accordance with the dynamic complex modulus. Furthermore, Wt / G* is preferably 30 or more, more preferably 40 or more, even more preferably 50 or more, and particularly preferably 60 or more.

[0022] The self-sealing tire of the present disclosure has a cross-sectional area of ​​the sealant layer of S (mm 2), S / G* is preferably 3000 or less, more preferably 2000 or less, even more preferably 1500 or less, even more preferably 1000 or less, still more preferably 900 or less, still more preferably 850 or less, and particularly preferably 800 or less. Furthermore, S / G* is preferably 100 or more, preferably 150 or more, even more preferably 200 or more, still more preferably 250 or more, and particularly preferably 300 or more. The self-sealing tire of the present disclosure has a small tire section width and a small dynamic complex modulus, which raises concerns about a decrease in steering stability. Therefore, it is believed that by increasing the cross-sectional area of ​​the sealant layer in accordance with the dynamic complex modulus, steering stability can be improved and air sealing performance can also be ensured.

[0023] In the self-sealing tire of the present disclosure, G*×S / Wt is preferably 30 or less, more preferably 20 or less, even more preferably 10 or less, still more preferably 8.0 or less, and particularly preferably 7.0 or less. G*×S / Wt is preferably 0.5 or more, more preferably 1.0 or more, and even more preferably 1.5 or more. The self-sealing tire of the present disclosure has a small tire section width and a small dynamic complex modulus, which raises concerns about a decrease in steering stability. Therefore, it is believed that by increasing the cross-sectional area of ​​the sealant layer in accordance with the dynamic complex modulus, steering stability can be improved and air sealing performance can also be ensured.

[0024] The self-sealing tire of the present disclosure preferably has an aspect ratio of 40% or more, more preferably 45% or more, even more preferably 47.5% or more, even more preferably 50% or more, still more preferably 52.5% or more, and particularly preferably 55% or more. By ensuring that the aspect ratio is within the above range, the height of the tire's sidewalls can be increased to suppress localized deformation of the tire, thereby further improving tire durability. The aspect ratio (%) is calculated by multiplying the cross-sectional height Ht (mm) and cross-sectional width Wt (mm) of the tire at an internal pressure of 250 kPa by (Ht / Wt) x 100.

[0025] The tire outer diameter Dt is preferably 515 mm or more, more preferably 558 mm or more, even more preferably 585 mm or more, and particularly preferably 632 mm or more. The tire outer diameter Dt is preferably less than 843 mm, more preferably less than 725 mm, even more preferably less than 707 mm, still more preferably less than 685 mm, and particularly preferably less than 655 mm.

[0026] The tire section width Wt is preferably 115 mm or more, more preferably 125 mm or more, even more preferably 150 mm or more, and particularly preferably 170 mm or more. The tire section width Wt is preferably less than 305 mm, more preferably less than 245 mm, even more preferably less than 210 mm, and particularly preferably less than 200 mm.

[0027] The tire section height Ht is preferably 37 mm or more, more preferably 60 mm or more, and even more preferably 80 mm or more. The tire section height Ht is preferably less than 180 mm, more preferably less than 152 mm, and even more preferably less than 115 mm.

[0028] In the self-sealing tire of the present disclosure, from the viewpoint of ride comfort stability during running, (Dt-2×Ht) is preferably 360 mm or more, more preferably 380 mm or more, even more preferably 400 mm or more, and particularly preferably 420 mm or more. On the other hand, from the viewpoint of deformation of the tread portion, it is preferably less than 560 mm, more preferably less than 530 mm, and even more preferably less than 510 mm.

[0029] In addition, the virtual volume V (mm) of the space occupied by the tire when it is mounted on a standard rim and the internal pressure is set to 250 kPa. 3 ) can be calculated from the following formula (2) based on the cross-sectional width Wt (mm), outer diameter Dt (mm), and cross-sectional height Ht (mm). V=[(Dt / 2) 2 -{(Dt / 2)-Ht} 2 ]×π×Wt (2)

[0030] The virtual volume V is 1.2×10 7 mm 3More than 1.6×10 is preferable. 7 mm 3 More preferably, 2.0 x 10 7 mm 3 On the other hand, the virtual volume V is 8.8×10 7 mm 3 Less than 6.6 x 10 is preferable. 7 mm 3 Less than 4.4 x 10 is preferable. 7 mm 3 Less than 3.9 × 10 is more preferable. 7 mm 3 Less than 1000 is particularly preferred.

[0031] In addition, the self-sealing tire of the present disclosure has a virtual volume V (mm 3 ) and the cross-sectional width Wt (mm) preferably satisfy the following formula (3): [(V+1.5×10 7 ) / Wt]≦4.02×10 5 ···(3)

[0032] In this way, by reducing the virtual volume V of the tire in accordance with the reduction in the cross-sectional width Wt of the tire and reducing the volume of the tire itself, it is possible to reduce the rate of growth of the outer diameter due to centrifugal force, thereby reducing the amount of deformation in the bead portion of the side and also suppressing rounding of the tread portion.

[0033] Virtual volume of tire V (mm 3 ) and the cross-sectional width Wt (mm) more preferably satisfy the following formula (4), and even more preferably satisfy the following formula (5). [(V+2.0×10 7 ) / Wt]≦4.02×10 5 ···(4) [(V+2.5×10 7 ) / Wt]≦4.02×10 5 ···(5)

[0034] The procedure for producing a self-sealing tire including a sealant layer, which is one embodiment of the present disclosure, is described in detail below. However, the following description is an example for explaining the present disclosure and is not intended to limit the technical scope of the present disclosure to only this described range. Note that in this specification, when a numerical range is indicated using "to" it is intended to include both ends of the range.

[0035] <Rubber component> A sealant tire can be produced by a conventional method, for example, by mixing the components constituting the sealant to prepare a sealant, and then applying the resulting sealant to the inner circumferential surface of a tire by coating or the like to form a sealant layer. The sealant tire has a sealant layer on the radially inner side of the inner liner. The sealant is not particularly limited as long as it has adhesive properties, and a typical rubber composition used for sealing punctures in tires can be used.

[0036] The rubber composition constituting the sealant layer according to the present disclosure (hereinafter, sometimes simply referred to as the "rubber composition of the present disclosure") preferably contains a butyl-based rubber as a rubber component. Examples of butyl-based rubber include butyl rubber (IIR) and halogenated butyl rubbers (X-IIR) such as brominated butyl rubber (Br-IIR) and chlorinated butyl rubber (Cl-IIR), with halogenated butyl rubber being preferred. Among these, brominated butyl rubber is particularly preferred because of its fast reactivity. It is preferable to use pelletized butyl-based rubber. This allows the butyl-based rubber to be accurately and appropriately supplied to the continuous mixer, enabling efficient production of the sealant material.

[0037] Other rubber components other than butyl rubber may be used in combination, such as diene rubbers such as natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene butadiene rubber (SBR), styrene isoprene butadiene rubber (SIBR), ethylene propylene diene rubber (EPDM), chloroprene rubber (CR), and acrylonitrile butadiene rubber (NBR). From the viewpoint of flowability, the content of butyl rubber in 100% by mass of the rubber component is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 81% by mass or more, even more preferably 85% by mass or more, even more preferably 87% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Alternatively, the rubber component may consist solely of butyl rubber.

[0038] The rubber composition of the present disclosure may contain, for example, a composite material or the like containing at least one functional group having metal coordinating ability in its molecular structure. The functional group having metal coordinating ability is not particularly limited as long as it has metal coordinating ability, and examples thereof include functional groups containing metal coordinating atoms such as oxygen, nitrogen, and sulfur. Specific examples include dithiocarbamic acid groups, phosphate groups, carboxylic acid groups, carbamic acid groups, dithioic acid groups, aminophosphate groups, and thiol groups. Only one type of the above functional group may be contained, or two or more types may be contained.

[0039] Examples of the metals coordinated to the functional group include Fe, Cu, Ag, Co, Mn, Ni, Ti, V, Zn, Mo, W, Os, Mg, Ca, Sr, Ba, Al, and Si. 1 In the case of polymer materials containing compounds having the metal-coordinating functional groups (such as -COO), each -COOM 1 are coordinated to form many -COOM 1 The metal atoms (M 1 The blending amount of ) is preferably 0.01 to 200 parts by mass per 100 parts by mass of the polymer component in the polymer material.

[0040] The rubber composition of the present disclosure preferably contains a liquid polymer. Examples of liquid polymers include liquid polybutene, liquid polyisobutene, liquid polyisoprene, liquid polybutadiene, liquid polyα-olefin, liquid isobutylene, liquid ethylene α-olefin copolymer, liquid ethylene propylene copolymer, and liquid ethylene butylene copolymer. Among these, liquid polybutene is preferred due to its good compatibility with butyl-based rubber. Examples of liquid polybutene include copolymers containing isobutene as the main component and having a molecular structure of long-chain hydrocarbons obtained by further reacting normal butene, and hydrogenated liquid polybutene can also be used.

[0041] The dynamic viscosity of the liquid polymer at 100°C is 100cSt (100mm 2 / s) or more, more preferably 200 cSt or more, even more preferably 5000 cSt or more, and particularly preferably 1000 cSt or more. 2 / s) or less, more preferably 5500 cSt or less, even more preferably 5000 cSt or less, and particularly preferably 4500 cSt or less. In the present disclosure, the kinematic viscosity of the liquid polymer is measured in accordance with ASTM D445.

[0042] The content of the liquid polymer per 100 parts by mass of the rubber component is preferably 50 parts by mass or more, more preferably 100 parts by mass or more, and even more preferably 150 parts by mass or more, from the viewpoint of air sealing performance, and is preferably 400 parts by mass or less, more preferably 350 parts by mass or less, and even more preferably 300 parts by mass or less, from the viewpoint of shape retention of the sealant.

[0043] The rubber composition of the present disclosure preferably contains an inorganic filler. Examples of the inorganic filler include carbon black, silica, and mM 2 ·xSiOy·zH2O (where M 2represents at least one metal selected from the group consisting of aluminum, calcium, magnesium, titanium and zirconium, or an oxide, hydroxide, hydrate or carbonate of said metal; m represents a number in the range of 1 to 5, x represents a number in the range of 0 to 10, y represents a number in the range of 2 to 5, and z represents a number in the range of 0 to 10.) From the viewpoint of preventing deterioration due to ultraviolet rays, carbon black is preferred.

[0044] The above mM 2 Specific examples of inorganic fillers represented by ·xSiOy·zH2O include aluminum hydroxide (Al(OH)3), alumina (Al2O3, Al2O3·3H2O), clay (Al2O3·2SiO2), kaolin (Al2O3·2SiO2·2H2O), pyrophyllite (Al2O3·4SiO2·H2O), bentonite (Al2O3·4SiO2·2H2O), aluminum silicate (Al2SiO5, Al4(SiO2)3·5H2O, etc.), and calcium aluminum silicate. (Al2O3·CaO·2SiO2), calcium hydroxide (Ca(OH)2), calcium oxide (CaO), calcium silicate (Ca2SiO4), calcium magnesium silicate (CaMgSiO4), magnesium hydroxide (Mg(OH)2), magnesium oxide (MgO), talc (MgO·4SiO2·H2O), attapulgite (5MgO·8SiO2·9H2O), aluminum magnesium oxide (MgO·Al2O3), titanium white (TiO2), titanium black (Ti n O 2n-1 In a rubber composition containing such a filler, the filler aggregates to form clusters. The amount of the filler to be compounded is preferably 10 to 200 parts by mass per 100 parts by mass of the rubber component.

[0045] The carbon black is not particularly limited, and those commonly used in the tire industry, such as GPF, FEF, HAF, ISAF, and SAF, can be used. Specifically, N110, N115, N120, N125, N134, N135, N219, N220, N231, N234, N293, N299, N326, N330, N339, N343, N347, N351, N356, N358, N375, N539, N550, N582, N630, N642, N650, N660, N683, N754, N762, N765, N772, N774, N787, N907, N908, N990, and N991 can be preferably used. In addition to these, in-house synthesized products can also be preferably used. These carbon blacks may be used alone or in combination of two or more.

[0046] The content of the inorganic filler (preferably carbon black) per 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, from the viewpoint of suppressing a decrease in sealing property due to deterioration by ultraviolet light. Also, from the viewpoint of suppressing a decrease in sealing property due to an increase in the viscosity of the sealant, the content is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less.

[0047] <Other compounding agents> In addition to the above components, the rubber composition of the present disclosure may appropriately contain compounding agents that are conventionally commonly used in the tire industry, such as oil, a resin component, wax, zinc oxide, stearic acid, an antioxidant, a crosslinking agent, and a vulcanization accelerator.

[0048] Examples of oils include process oil, vegetable oils, and animal fats. Examples of the process oil include paraffinic process oil, naphthenic process oil, and aromatic process oil. Furthermore, as an environmental measure, process oil with a low content of polycyclic aromatic compounds (PCA) can also be used. Examples of the low-PCA process oil include mild extract solvates (MES), treated distillate aromatic extracts (TDAE), and heavy naphthenic oil.

[0049] When oil is contained, the amount per 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, and is preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 15 parts by mass or less.

[0050] The resin component is not particularly limited, but examples thereof include petroleum resins, terpene resins, rosin resins, phenolic resins, etc., which are commonly used in the tire industry, and petroleum resins are preferred. These resin components may be used alone or in combination of two or more.

[0051] When a resin component is contained, the content per 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 15 parts by mass or more, and is preferably 100 parts by mass or less, more preferably 60 parts by mass or less, even more preferably 40 parts by mass or less, and particularly preferably 30 parts by mass or less.

[0052] When stearic acid is contained, the content per 100 parts by mass of the rubber component is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, from the viewpoint of processability, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, from the viewpoint of vulcanization rate.

[0053] When zinc oxide is contained, the content per 100 parts by mass of the rubber component is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 4 parts by mass or more, and particularly preferably 6 parts by mass or more, from the viewpoint of shape retention of the sealant, and is preferably 20 parts by mass or less, more preferably 18 parts by mass or less, even more preferably 15 parts by mass or less, and particularly preferably 12 parts by mass or less, from the viewpoint of air sealing performance.

[0054] Examples of vulcanizing agents include sulfur, organic peroxides, alkylphenol-sulfur chloride condensates, sodium 1,6-hexamethylenedithiosulfate dihydrate, 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane, etc. Examples of sulfur that can be used include powdered sulfur, oil-treated sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, and highly dispersible sulfur.

[0055] When a vulcanizing agent is contained, the content thereof per 100 parts by mass of the rubber component is preferably less than 1.0 part by mass, more preferably less than 0.5 part by mass, even more preferably less than 0.1 part by mass, and particularly preferably less than 0.01 part by mass, from the viewpoint of suppressing heat aging of the sealant layer and ensuring air sealing performance until the end of running, and the vulcanizing agent may not be contained. Note that when oil-containing sulfur is used as the vulcanizing agent, the content of the vulcanizing agent is the total content of pure sulfur contained in the oil-containing sulfur.

[0056] The vulcanization accelerator is not particularly limited, but examples thereof include sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamate-based, aldehyde-amine-based, aldehyde-ammonia-based, imidazoline-based, xanthogenic acid-based, and quinonedioxime compound (quinoid compound) vulcanization accelerators, and among these, sulfenamide-based, thiazole-based, and guanidine-based vulcanization accelerators are preferred because they more suitably achieve the desired effects.

[0057] Examples of sulfenamide vulcanization accelerators include N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-(tert-butyl)-2-benzothiazolylsulfenamide (TBBS), N-oxyethylene-2-benzothiazolylsulfenamide, N,N'-diisopropyl-2-benzothiazolylsulfenamide, and N,N-dicyclohexyl-2-benzothiazolylsulfenamide. Examples of thiazole vulcanization accelerators include 2-mercaptobenzothiazole and di-2-benzothiazolyl disulfide. Examples of thiuram vulcanization accelerators include tetramethylthiuram monosulfide, tetramethylthiuram disulfide, and tetrabenzylthiuram disulfide (TBzTD). Examples of guanidine vulcanization accelerators include diphenyl guanidine (DPG), di-orthotolyl guanidine, and orthotolyl biguanidine. Examples of dithiocarbamate vulcanization accelerators include zinc dimethyldithiocarbamate (ZnMDC). These vulcanization accelerators may be used alone or in combination of two or more.

[0058] When a vulcanization accelerator is contained, the content thereof per 100 parts by mass of the rubber component is preferably 8.0 parts by mass or less, more preferably 7.0 parts by mass or less, and even more preferably 6.0 parts by mass or less. The lower limit of the content is not particularly limited, and can be, for example, 0.1 parts by mass or more, 0.5 parts by mass or more, 1.0 parts by mass or more, 1.5 parts by mass or more, 2.0 parts by mass or more, or 2.5 parts by mass.

[0059] Furthermore, from the viewpoint of suppressing thermal aging of the sealant layer and ensuring air sealing performance until the end of the running period, the content of the vulcanization accelerator can be, for example, less than 1.0 part by mass, less than 0.5 parts by mass, less than 0.1 parts by mass, or less than 0.01 parts by mass, and it is also possible for the vulcanization accelerator to be absent.

[0060] The content of the thiuram vulcanization accelerator per 100 parts by mass of the rubber component is preferably less than 1.0 part by mass, more preferably less than 0.5 part by mass, even more preferably less than 0.1 part by mass, and particularly preferably less than 0.01 part by mass, and the rubber composition may not contain a thiuram vulcanization accelerator.

[0061] The content of the dithiocarbamate vulcanization accelerator per 100 parts by mass of the rubber component is preferably less than 1.0 part by mass, more preferably less than 0.5 part by mass, even more preferably less than 0.1 part by mass, particularly preferably less than 0.01 part by mass, and the dithiocarbamate vulcanization accelerator may not be contained.

[0062] A sealant tire having a sealant layer A on the radially inner side of the inner liner can be manufactured by mixing the aforementioned materials to prepare a sealant and applying the prepared sealant to the inner circumferential surface of the tire (preferably the radially inner portion of the inner liner). The materials constituting the sealant can be mixed using, for example, a known continuous mixer. Among these, mixing using a co-rotating or counter-rotating multi-screw kneading extruder, particularly a twin-screw kneading extruder, is preferred.

[0063] Mixing in a continuous mixer (particularly a twin-screw mixer / extruder) is preferably carried out at a barrel temperature of 30°C (preferably 50°C) to 150°C from the viewpoints of ease of mixing, extrudability, dispersibility, and crosslinking reaction.

[0064] From the viewpoint of sufficient mixing, the mixing time of the materials is preferably 1 to 30 minutes, more preferably 2 to 20 minutes. In the present disclosure, the mixing time refers to the residence time from when the materials are supplied to a continuous mixer (particularly a twin-screw mixer / extruder) until when they are discharged.

[0065] The temperature of the sealant material discharged from the outlet can be adjusted by adjusting the screw rotation speed of the continuous mixer (particularly a twin-screw mixer / extruder) and the settings of the temperature regulator, which in turn controls the cure acceleration rate of the sealant material. In a continuous mixer (particularly a twin-screw mixer / extruder), increasing the screw rotation speed increases the mixability and material temperature. Note that the screw rotation speed does not affect the discharge rate. From the viewpoint of sufficient mixing and control of the cure acceleration rate, the screw rotation speed is preferably 50 to 700 rpm, and more preferably 50 to 550 rpm.

[0066] The temperature of the sealant discharged from the outlet of a continuous mixer (particularly a twin-screw mixer / extruder) is preferably 70 to 150°C, more preferably 90 to 130°C, from the viewpoints of sufficient mixing and control of the cure acceleration rate. When the temperature of the sealant is within the above range, the crosslinking reaction begins at the time of application, and the sealant has good adhesion to the inner circumferential surface of the tire and the crosslinking reaction proceeds more suitably, making it possible to produce a sealant tire with good sealing properties and without the need for a crosslinking step.

[0067] The sealant may be applied to at least the inner circumferential surface of the tire corresponding to the tread, more preferably at least the inner circumferential surface of the tire corresponding to the breaker. By omitting application of the sealant to areas where it is not necessary, a sealant tire can be manufactured with higher productivity. Here, the inner circumferential surface of the tire corresponding to the tread means the inner circumferential surface of the tire located radially inward of the tread that contacts the road surface, and the inner circumferential surface of the tire corresponding to the breaker means the inner circumferential surface of the tire located radially inward of the breaker. The breaker is a component equipped with cords such as steel cords that is arranged inside the tread and radially outward of the carcass.

[0068] The sealant layer A is preferably formed by continuously and spirally applying a generally string-shaped sealant to the inner circumferential surface of the tire. When the sealant is generally string-shaped, a sealant layer A consisting of a single layer of sealant can be formed by continuously and spirally applying the sealant to the inner circumferential surface of the tire. When the sealant is generally string-shaped, the applied sealant has a certain thickness, so that even with a sealant layer consisting of a single layer of sealant, deterioration of tire uniformity can be prevented, and a sealant tire with excellent weight balance and good sealing properties can be produced. Furthermore, because it is necessary to apply only one layer of sealant rather than stacking multiple layers, sealant tires can be produced with higher productivity.

[0069] The number of times the sealant is wrapped around the inner circumferential surface of the tire is preferably 20 to 70 times, more preferably 20 to 60 times, and even more preferably 35 to 50 times, because this can prevent deterioration of tire uniformity, provide excellent weight balance, and enable more productive production of sealant tires with good sealing properties. Here, wrapping twice means that the sealant is applied so that it wraps around the inner circumferential surface of the tire twice.

[0070] From the viewpoint of reliably sealing the puncture hole when the tire is punctured, the thickness of the sealant layer A is preferably 1.0 mm or more, more preferably 1.5 mm or more, even more preferably 2.0 mm or more, and particularly preferably 2.5 mm or more. There is no particular upper limit to the thickness of the sealant layer A, but it is preferably 10.0 mm or less, more preferably 8.0 mm or less, even more preferably 5.0 mm or less, and particularly preferably 4.0 mm or less. The thickness of the sealant can be adjusted by adjusting the tire rotation speed, the tire widthwise movement speed, the distance between the nozzle tip and the inner circumferential surface of the tire, etc.

[0071] It is preferable that the thickness of the sealant layer A is substantially constant. This can better prevent deterioration of tire uniformity and produce a self-sealing tire with better weight balance. Here, in this specification, "substantially constant thickness" means that the thickness fluctuation is within 90 to 110% (preferably 95 to 105%, more preferably 98 to 102%, and even more preferably 99 to 101%).

[0072] The cross-sectional area S of the sealant layer A is 50 mm 2 More than 100mm is preferable. 2 More than 150mm is more preferable. 2 More preferably, 200 mm or more 2 The above is particularly preferable. In addition, the cross-sectional area S of the sealant layer A is 1500 mm 2 Less than 1200mm is preferable 2 Less than 1000mm is preferable. 2 Less than 800mm is more preferable 2Less than 700mm is more preferable. 2 Less than 600mm is more preferable 2 The following are particularly preferred:

[0073] The dynamic complex modulus G* herein refers to the dynamic complex modulus (kPa) measured in accordance with ISO 13145 under conditions of 100°C atmosphere, 100% strain, and 0.1 Hz frequency. From the viewpoints of maintaining the shape of the sealant and improving handling stability, the G* of the sealant layer A is 0.50 kPa or more, preferably 0.55 kPa or more, more preferably 0.60 kPa or more, even more preferably 0.65 kPa or more, and particularly preferably 0.70 kPa or more. On the other hand, from the viewpoint of air sealing performance, the G* of the sealant layer is 3.50 kPa or less, preferably 3.20 kPa or less, more preferably 2.90 kPa or less, even more preferably 2.70 kPa or less, even more preferably 2.50 kPa or less, even more preferably 2.30 kPa or less, and particularly preferably 2.10 kPa or less.

[0074] The G* of the sealant layer A can be adjusted as appropriate by adjusting the liquid polymer content, the dynamic viscosity of the liquid polymer, the zinc oxide content, etc. Specifically, the G* value tends to decrease as the liquid polymer content increases, and conversely, the G* value tends to increase as the liquid polymer content decreases. The G* value tends to increase as the dynamic viscosity of the liquid polymer increases, and conversely, the G* value tends to decrease as the liquid polymer content decreases. The G* value tends to increase as the zinc oxide content increases, and conversely, the G* value tends to decrease as the zinc oxide content decreases.

[0075] In this specification, the term "elongation at break (EB) (%)" refers to the elongation at break (elongation at break) measured in accordance with JIS K 6251:2017 at a tensile speed of 500 mm / sec in an atmosphere of 25°C. From the viewpoint of ensuring air sealing performance at low temperatures, the EB of the sealant layer A is preferably 500% or more, more preferably 520% ​​or more, and even more preferably 540% or more. The upper limit of the EB is not particularly limited.

[0076] The self-sealing tire of the present disclosure may have a sound absorbing layer B provided on the radially inner side of the inner liner. Because the sealant material constituting the sealant layer A has adhesive strength, the sound absorbing layer B can be easily provided on the radially inner side of the sealant layer A by bringing the sound absorbing layer B into contact with the sealant layer A.

[0077] Any material that can exert a sound-damping effect in the tire cavity can be suitably used as the sound-absorbing layer B. The sound-absorbing layer B is made of, for example, a porous sponge material. The sponge material is a spongy porous structure, and includes, for example, a sponge itself with open cells formed by foaming rubber or synthetic resin, as well as a web-like structure formed by intertwining animal fibers, plant fibers, synthetic fibers, or the like. The term "porous structure" also includes those with not only open cells but also closed cells. From the standpoints of sound-damping properties, light weight, foam adjustability, durability, and the like, a sponge material made of polyurethane is suitably used as the sound-absorbing layer B. [Example]

[0078] Hereinafter, the present disclosure will be described based on examples, but the present disclosure is not limited to these examples.

[0079] The various chemicals used in the examples and comparative examples are listed below. Butyl rubber: Bromobutyl 2255 (brominated butyl rubber) manufactured by JSR Corporation Carbon black: Diablack H (N330) manufactured by Mitsubishi Chemical Corporation Liquid polymer 1: HV-1900 manufactured by ENEOS Corporation (liquid polybutene, kinematic viscosity at 100°C: 3710 cSt) Liquid polymer 2: HV-100 manufactured by ENEOS Corporation (liquid polybutene, kinematic viscosity at 100°C: 220 cSt) Liquid polymer 3: Lucant HC-1100 (liquid ethylene α-olefin copolymer, kinematic viscosity at 100°C: 1100 cSt) manufactured by Mitsui Chemicals, Inc. Resin component: Quintone A100 (aliphatic hydrocarbon resin) manufactured by Zeon Corporation Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. Stearic acid: Camellia stearic acid beads manufactured by NOF Corporation

[0080] Examples and Comparative Examples According to the formulations shown in Tables 1 and 2, butyl rubber, carbon black, liquid polymer, resin component, zinc oxide, stearic acid, and optional vulcanization accelerator were charged into a 3-L twin-screw extruder and mixed at a barrel temperature of 120-135°C and 200 rpm to prepare sealants. The sealant (approximately string-like, 3 mm thick, 4 mm wide) was extruded from the twin-screw extruder and continuously spirally applied through a nozzle to the inner circumferential surface of each tire shown in Table 1 (size: 175 / 55R20, rim: 5.5x20J) and Table 2 (size: 205 / 55R16, rim: 6.5x16J) to form a sealant layer, thereby producing test tires. The resulting sealants and test tires were evaluated as follows.

[0081] <Measurement of dynamic complex modulus G*> The dynamic complex modulus G* of each punched rubber test piece was measured using a Premier RPA manufactured by Alpha Technologies in accordance with ISO 13145 under the conditions of a 100°C atmosphere, 100% strain, and a frequency of 0.1 Hz.

[0082] <Tensile test> A 1 mm thick dumbbell-shaped No. 7 test piece was cut from inside the sealant layer of each test tire so that the tensile direction was the tire circumferential direction, and a tensile test was carried out in accordance with JIS K 6251:2017 at a temperature of 25°C and a tensile speed of 500 mm / sec to measure the elongation at break EB (%). The thickness direction of the sample was the tire radial direction.

[0083] <Handling stability> Each test tire was mounted on all wheels of a vehicle (a domestically produced FF vehicle with an engine displacement of 2000cc), which was driven around a test course with a dry asphalt road surface, and the lap time was measured. The handling stability was expressed as an index using the following formula. A higher index indicates better handling stability. The reference tire is a tire without a sealant layer, and is a tire whose lap time is longer (slower) than those of the examples and comparative examples. The reference comparative example is the tire of comparative example 2 in Table 1, and the tire of comparative example 4 in Table 2. (Handling stability performance) = [(Lap time of reference tire - Lap time of test tire) / (Lap time of reference tire - Lap time of reference comparative tire)] x 100

[0084] <Air seal performance> A nail with a diameter of 4 mm and a length of 50 mm was driven into a sealant tire prepared by the above method while it was inflated to an internal pressure of 230 kPa. After 3 hours, the nail was removed and the internal pressure was measured immediately afterwards. The air sealing performance was expressed as an index using the following formula. The reference comparative example is the tire of Comparative Example 2 in Table 1 and the tire of Comparative Example 4 in Table 2. The larger the index, the smaller the drop in internal pressure and the better the air sealing performance. (Air seal performance index) = (internal pressure of each test tire) / (internal pressure of standard comparative tire) × 100

[0085] The target performance value for the overall performance of handling stability and air seal performance (the sum of the handling stability performance index and the air seal performance index) is over 200.

[0086] [Table 1]

[0087] [Table 2]

[0088] The results in Tables 1 and 2 show that the sealant tires of the present disclosure, which have tire cross-sectional width, tire outer diameter, and sealant layer dynamic complex modulus within specified ranges, have improved overall performance in terms of handling stability and air sealing performance.

[0089] <Embodiment> Examples of embodiments of the present disclosure are provided below.

[0090] [1] A self-sealing tire having a sealant layer on its inner peripheral surface, wherein when the self-sealing tire is mounted on a regular rim and the internal pressure is set to 250 kPa, Wt (mm) is the cross-sectional width of the self-sealing tire, and Dt (mm) is the outer diameter of the self-sealing tire, and Wt and Dt satisfy the following formula (1), and the dynamic complex modulus G* of the self-sealing tire, measured in accordance with ISO 13145 under conditions of an atmosphere of 100°C, 100% strain, and a frequency of 0.1 Hz, is 0.50 to 3.50 kPa (preferably 0.55 to 3.20 kPa, more preferably 0.60 to 2.90 kPa, and even more preferably 0.65 to 2.70 kPa). 1600≦(Dt 2 ×π / 4) / Wt≦2827.4 (1) [2] The self-sealing tire according to [1] above, having a Dt / G* of 150 or more. [3] The self-sealing tire according to [2] above, having a Dt / G* of 240 or more. [4] The cross-sectional area of ​​the sealant layer is S (mm 2 ) the S / G* is 100 to 3000. [5] The self-sealing tire according to [4] above, wherein S / G* is 150 to 900. [6] The cross-sectional area of ​​the sealant layer is S (mm 2 ) the self-sealing tire according to any one of [1] to [5] above, wherein G*×S / Wt is 0.5 to 30. [7] The self-sealing tire according to the above [6], wherein G*×S / Wt is 1.0 to 10. [8] The self-sealing tire according to any one of the above [1] to [7], having an aspect ratio of 40% or more (preferably 45% or more, more preferably 50% or more, and even more preferably 55% or more). [9] The self-sealing tire according to any one of the above [1] to [8], wherein the outer diameter Dt of the self-sealing tire is less than 843 mm (preferably less than 725 mm, more preferably less than 707 mm, and even more preferably less than 685 mm).

[10] The self-sealing tire according to any one of [1] to [9] above, wherein the cross-sectional width Wt of the self-sealing tire is less than 305 mm (preferably less than 245 mm, more preferably less than 210 mm, and even more preferably less than 200 mm).

[11] A self-sealing tire according to any one of [1] to

[10] above, wherein, when the cross-sectional height of the self-sealing tire is Ht (mm) when mounted on a regular rim and the internal pressure is set to 250 kPa, (Dt-2×Ht) is 360 mm or more (preferably 380 mm or more, more preferably 400 mm or more, and even more preferably 420 mm or more).

[12] The virtual volume V (mm 3 The self-sealing tire according to any one of the above [1] to

[11] , wherein Wt satisfies the following formula (3): [(V+1.5×10 7 ) / Wt]≦4.02×10 5 ···(3)

[13] The virtual volume V (mm 3 ) and the Wt satisfy the following formula (4). [(V+2.0×10 7 ) / Wt]≦4.02×10 5 ···(4)

[14] The virtual volume V (mm 3 ) and the Wt satisfy the following formula (5). [(V+2.5×10 7 ) / Wt]≦4.02×10 5 ···(5) [Explanation of symbols]

[0091] A. Sealant layer B: Sound-absorbing layer Wt: Section width of sealant tire Dt...Outer diameter of sealant tire Ht: Section height of sealant tire

Claims

1. A self-sealing tire having a sealant layer on the inner circumferential surface of the tire, When the self-sealing tire is mounted on a regular rim and the internal pressure is set to 250 kPa, the cross-sectional width of the self-sealing tire is Wt (mm) and the outer diameter is Dt (mm), and Wt and Dt satisfy the following formula (1): the sealant layer has a dynamic complex modulus G* of 0.50 to 3.50 kPa as measured in accordance with ISO 13145 under conditions of a 100°C atmosphere, a 100% strain, and a frequency of 0.1 Hz; Dt / G* is 240 or more, The self-sealing tire has an S / G* ratio of 100 to 3,000, where S (mm 2 ) is the cross-sectional area of ​​the sealant layer. 1600≦(Dt 2 ×π / 4) / Wt≦2827.4 ・・・(1)

2. 2. The self-sealing tire according to claim 1, wherein S / G* is 150 to 900.

3. A sealant tire according to claim 1 or 2, wherein G*×S / Wt is 0.5 to 30.

4. 3. The self-sealing tire according to claim 1, wherein G*×S / Wt is 1.0 to 10.

5. The self-sealing tire according to any one of claims 1 to 4, wherein the aspect ratio is 40% or more.

6. The self-sealing tire according to any one of claims 1 to 5, wherein the self-sealing tire has an outer diameter Dt of less than 843 mm.

7. The self-sealing tire according to any one of claims 1 to 6, wherein the self-sealing tire has a cross-sectional width Wt of less than 305 mm.

8. The self-sealing tire according to any one of claims 1 to 7, wherein, when the cross-sectional height of the self-sealing tire is Ht (mm) when mounted on a regular rim and subjected to an internal pressure of 250 kPa, (Dt - 2 x Ht) is 360 mm or more.

9. The virtual volume V (mm 3 9. The self-sealing tire according to claim 1, wherein Wt satisfies the following formula (3): [(V+1.5×10) 7 ) / Wt]≦4.02×10 5 ・・・(3)

10. The virtual volume V (mm 3 10. The self-sealing tire according to claim 9, wherein Wt satisfies the following formula (4): [(V+2.0×10) 7 ) / Wt]≦4.02×10 5 ・・・(4)

11. The virtual volume V (mm 3 11. The self-sealing tire according to claim 10, wherein Wt satisfies the following formula (5): [(V+2.5×10) 7 ) / Wt]≦4.02×10 5 ・・・(5)

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