High-load capacity tire with tear-resistant sidewalls

Abstract

A passenger vehicle tire (10) includes a crown (12), two beads (32), and two sidewalls (30) connecting each bead (32) to the crown (12). The tire (10) is of the high-load capacity type as defined in the 2021 ETRTO standard manual. At least one of the two sidewalls (30) contains an elastomer composition based on at least one elastomer matrix, at least one reinforcing filler, and at least one rubber powder. The sum of the reinforcing filler content and the rubber powder content is 30 phr or more. The mass ratio of the rubber powder content, expressed in phr, to the reinforcing filler content, expressed in phr, is in the range of 0.20 to 1.50.

Description

Technical Field

[0001] The present invention relates to a tire. The term "tire" should be understood to mean a tire casing intended to form a cavity by interacting with a support element, such as a rim, which cavity can be pressurized to a pressure higher than atmospheric pressure. The tire according to the present invention has a substantially annular structure that exhibits rotational symmetry about the main axis of the tire.

Background Art

[0002] The advent of electric or hybrid passenger vehicles has led to an increase in the weight of the vehicle, particularly due to the battery. The weight of the battery is relatively large and is substantially proportional to the cruising range (autonomous driving range) of the vehicle. Therefore, for example, in order to extend the cruising range of an electric vehicle, it is necessary to increase the size of its battery, resulting in an increase in the weight of the vehicle. Put simply, it is currently estimated that the vehicle weight increases by 1 kilogram for every 1 kilometer increase in the cruising range of an electric motor. Therefore, in order to achieve a cruising range of 500 kilometers, it is necessary to increase the weight of a vehicle propelled by a combustion engine by approximately 500 kg. Such a vehicle needs to be equipped with tires that can withstand very high loads. Therefore, tire manufacturers decided to develop a new type of tire. This new type became known as "High Load Capacity" (or High Load) in the 2021 ETRTO standard manual. This new tire makes it possible to guarantee that a tire of a certain size can withstand a higher load than an extra-load tire of the same size. For example, in the 255 / 35R18 size, the High Load Capacity tire has a load index equivalent to 98, suggesting that it can withstand a load of 750 kg at a pressure of 290 kPa. For comparison, in the same 255 / 35R18 size, the extra-load tire has a load index equivalent to 94, suggesting that it can withstand a load of 670 kg at a pressure of 290 kPa. One problem encountered is that, in certain sizes, high-load capacity tires are required to withstand relatively high loads, which can cause significant flexing of the sidewall and make them susceptible to tearing, especially when driving over deep potholes or large bumps in the road, when suddenly driving onto paved roads, when used at pressures significantly lower than recommended, or when used at loads significantly higher than maximum loads. [Overview of the Initiative]

[0003] The objective of the present invention is to provide a tire that can withstand a greater load than existing tires, while simultaneously increasing its tear strength. For this purpose, the present invention relates to a tire for a passenger vehicle, comprising a crown, two beads, and two sidewalls connecting each bead to the crown, wherein the tire is of the high-load capacity type as defined in the 2021 ETRTO Standards Manual, and at least one of the two sidewalls comprises an elastomer composition based on at least one elastomer matrix, at least one reinforcing filler, and at least one rubber powder, wherein the sum of the reinforcing filler content and the rubber powder content is in the range of 46 to 62 phr, and the mass ratio of the rubber powder content expressed in phr to the reinforcing filler content expressed in phr is in the range of 0.20 to 1.50. To our surprise, the inventors discovered that one way to solve this problem is to use a specific elastomer composition based on at least one elastomer matrix, at least one reinforcing filler, and at least one rubber powder, having certain weight characteristics of the reinforcing filler content and the rubber powder content. This elastomer composition has excellent tear strength.

[0004] According to the present invention, the tire is for passenger vehicles. Such a tire is defined, for example, in the 2021 edition of the ETRTO (European Tire and Rim Technology Organization) Standards Manual. Such a tire generally has markings on at least one sidewall that conform to the markings of the 2021 edition of the ETRTO Standards Manual, indicating the tire size in the form X / YαVUβ, where X represents the nominal section width, Y represents the nominal aspect ratio, α represents the structure and can be R or ZR, V represents the nominal rim diameter, U represents the load index, and β represents the speed symbol. By increasing the load index of the tire compared to the load index of a tire of the same size in its extra-load specification, the present invention enables an increase in the load-bearing capacity of the tire without altering the dwelling space, compactness, and comfort of the vehicle in which it is used. Specifically, since the size of the tire of the present invention is the same as the size of its extra-load specification tire, this tire does not occupy more space than its extra-load specification tire. The tire of the present invention may be marked with a distinctive designation, such as HL (High Load) or XL+ (Extra Load+), so that it can be distinguished from both its standard load specification and its extra-load specification. Such designations are disclosed, in particular, on page 3 of the section titled "General Notes - Passenger Car Tires" in the 2021 ETRTO Standards Manual, in order to specify high-load capacity tires. Examples of sizes are also disclosed on page 44, paragraph 9.1, of the section titled "Passenger Car Tires - Metric Designation" in the 2021 ETRTO Standards Manual.

[0005] High-load capacity tires may be characterized by their load index LI such that LI ≥ LI'+1 (wherein LI' is the load index of an extra-load tire of the same size, in accordance with the 2021 ETRTO Standards Manual). The load index LI' is the load index of an extra-load tire of the same size, i.e., the same nominal section width, the same nominal aspect ratio, the same construction (R and ZR are considered identical), and the same nominal rim diameter. The load index LI' is given in the 2021 ETRTO Standards Manual, particularly on pages 22-43 of the section titled "Passenger car tires - Metric specified tires". LI = LI'+1, or LI = LI'+2, or LI = LI'+3, or LI = LI'+4, depending on the size. In most embodiments, LI'+1 ≤ LI ≤ LI'+4, and furthermore, LI'+2 ≤ LI ≤ LI'+4. The tire according to the present invention has a substantially annular shape with respect to a rotation axis that substantially coincides with the tire's axis of rotation. This rotation axis defines three directions as conventionally used by those skilled in the art: axial, circumferential, and radial. The term "axial direction" refers to the direction substantially parallel to the tire's axis of rotation, i.e., the tire's axis of rotation. The term "circumferential direction" refers to a direction that is substantially perpendicular to both the axial direction and the radius of the tire (in other words, a direction tangent to the circle centered on the tire's axis of rotation).

[0006] The term "radial direction" refers to any direction along the radius of the tire, that is, any direction that intersects the tire's axis of rotation and is substantially perpendicular to that axis. The term "midline of the tire" (indicated by M) refers to a plane located axially midway between the two beads, passing through the axial center of the crown reinforcement, and perpendicular to the tire's axis of rotation. The expression "tire equatorial plane" refers to a combination of planes that pass through the tire equator (indicated as E) in each meridian section and are perpendicular to the median plane and radial direction. The tire equator is an axis parallel to the tire's axis of rotation in the meridian section (a plane perpendicular to the circumferential direction and parallel to the radial and axial directions), and is equidistant from the outermost point in the radial direction of the tread intended to contact the ground and the innermost point in the radial direction of the tire intended to contact a support, such as the rim, and the distance between these two points is equal to H. The term "meridian plane" refers to a plane that is parallel to and contains the axis of rotation of the tire, and is perpendicular to the circumferential direction.

[0007] The terms "radially inward / inside" and "radially outward / outside" mean closer to the tire's axis of rotation and further away from the tire's axis of rotation, respectively. The terms "axially inward / inside" and "axially outward / outside" mean closer to the tire's midline and further away from the tire's midline, respectively. The term "bead" refers to the portion of a tire intended to enable it to be mounted to a mounting support, such as a wheel including a rim. Therefore, each bead is specifically intended to allow mounting in contact with the flange of the rim. Accordingly, the radially outer edge of the outer surface of the tire bead is defined, in accordance with the 2021 ETRTO standard manual, as the radially outermost point on the outer surface of the tire in contact with the measuring rim when the tire is inflated to its nominal pressure on this measuring rim. The expression "between a and b" indicates a range of values ​​from a value greater than a to a value less than b (i.e., excluding endpoints a and b), while the expression "from a to b" indicates a range of values ​​from a to b (i.e., strictly including endpoints a and b).

[0008] The expression “composition based on” should be understood to mean a composition comprising a mixture of the various components used and / or the products of an in situ reaction, some of which are intended to react, at least partially, during the various stages of the preparation of the composition and / or react with each other, and for this reason the composition may be fully or partially crosslinked or uncrosslinked. For the purposes of this invention, the expression "parts by mass per 100 parts by mass of elastomer" (or phr) should be understood to mean parts by mass per 100 parts by mass of elastomer in the sense of the preparation of the composition before curing. In other words, if rubber powder is present, the term "phr" means parts by mass per 100 parts of "novel" elastomer, and therefore the elastomer contained in the rubber powder is excluded from the base 100. In this text, unless otherwise indicated, all percentages (%) expressed are mass percentages (%). When referring to a “main” compound, this means that, for the purposes of the present invention, this compound is dominant among the compounds of the same type in the composition, i.e., it represents the largest amount by mass among the compounds of the same type. Thus, for example, the main elastomer is the elastomer that represents the largest mass relative to the total mass of elastomers in the composition. Similarly, the “main” filler is the one that represents the largest mass among the fillers in the composition. For example, in a system containing only one elastomer, the latter is dominant for the purposes of the present invention, and in a system containing two elastomers, the main elastomer represents more than half the mass of these elastomers. In contrast, the “lesser” compound is the compound that does not represent the largest mass fraction among the compounds of the same type. Preferably, the term “main” means present in amounts greater than 50%, preferably greater than 51%, greater than 60%, greater than 70%, greater than 80%, greater than 90%, and more preferably the “main” compound represents 100%.

[0009] The compounds referred to herein may be of fossil origin or may be derived from biological sources. In the latter case, the compounds may be partially or completely biomass-derived or obtained from renewable biomass-derived raw materials. Clearly, the compounds referred to may be derived from recycled materials already in use; that is, the compounds may be partially or completely derived from recycling processes or obtained from raw materials whose raw materials themselves are derived from recycling processes. In particular, these include polymers, plasticizers, fillers, and the like. The elastomer composition comprises at least one elastomer, for example, a diene elastomer. In some arbitrary embodiments, the elastomer composition comprises several elastomers, in particular several diene elastomers. For the remainder of this specification, this elastomer or this mixture of elastomers, in particular diene elastomers, is referred to as the elastomer matrix. If the composition comprises several elastomers, these elastomers are, of course, all different from one another.

[0010] The term "elastomer" refers to a polymer with elastic properties obtained after crosslinking, i.e., a homopolymer or copolymer. The term "rubber" is a common synonym for elastomer. "Diene elastomers" (or, without distinction, "diene rubbers"), whether natural or synthetic, refer to elastomers (i.e., homopolymers or copolymers) that are at least partially composed of diene monomer units (monomers that hold two conjugated or unconjugated carbon-carbon double bonds), as is well known. By definition, diene elastomers are non-thermoplastic. Preferably, the elastomer matrix comprises at least two different diene elastomers. These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated." "Essentially unsaturated" is intended to mean diene elastomers derived from conjugated diene monomers that generally contain at least a portion of diene-derived units (conjugated dienes) greater than 15% (mol%). For this reason, diene elastomers such as butyl rubber or copolymers of dienes and EPDM-type α-olefins do not fit the above definition and may be specifically referred to as "essentially saturated" diene elastomers (low or very low content, always less than 15% diene-derived units).

[0011] The diene elastomers that can be used in elastomer compositions are understood to mean, in particular, the following: - Any homopolymer of conjugated or unconjugated diene monomers having 4 to 18 carbon atoms; - Any copolymer of a conjugated or unconjugated diene having 4 to 18 carbon atoms and at least one other monomer, the other monomer may be ethylene, an olefin, or a conjugated or unconjugated diene. Suitable conjugated dienes include those containing 4 to 12 carbon atoms, particularly 1,3-dienes, especially 1,3-butadiene and isoprene. Suitable non-conjugated dienes include those containing 6 to 12 carbon atoms, such as 1,4-hexadiene, ethylidene norbornene, or dicyclopentadiene. Suitable olefins include vinyl aromatic compounds containing 8 to 20 carbon atoms and aliphatic α-monoolefins containing 3 to 12 carbon atoms.

[0012] Suitable vinyl aromatic compounds include, for example, styrene, ortho-, meta-, or para-methylstyrene, a commercially available mixture called "vinyltoluene," or para-(tert-butyl)styrene. Suitable aliphatic α-monoolefins include acyclic aliphatic α-monoolefins, in particular, that contain 3 to 18 carbon atoms. More specifically, diene elastomers are as follows: - Any homopolymer of conjugated diene monomers, in particular any homopolymer obtained by polymerization of conjugated diene monomers having 4 to 12 carbon atoms; - Any copolymer obtained by copolymerization of one or more conjugated dienes with each other or by copolymerization with one or more vinyl aromatic compounds having 8 to 20 carbon atoms; - Any copolymer obtained by copolymerization of one or more conjugated or non-conjugated dienes with ethylene, α-monoolefins, or mixtures thereof, such as elastomers obtained from ethylene and the above-mentioned non-conjugated diene monomers, or from propylene and the above-mentioned non-conjugated diene monomers.

[0013] According to an advantageous embodiment that enables improved tear strength, the elastomer matrix comprises at least one isoprene elastomer and at least one butadiene elastomer. The term "isoprene elastomer" means, in known ways, isoprene homopolymer or isoprene copolymer; in other words, isoprene elastomers may be selected from the group consisting of natural rubber (NR), synthetic polyisoprene (IR), various isoprene copolymers, and mixtures of these elastomers. Isoprene copolymers particularly include isobutene / isoprene (butyl rubber-IIR), isoprene / styrene (SIR), isoprene / butadiene (BIR), or isoprene / butadiene / styrene (SBIR) copolymers. Preferably, isoprene elastomers may be selected from the group consisting of natural rubber, synthetic cis-1,4-polyisoprene, and mixtures of these elastomers. More preferably, isoprene elastomers are further selected from the group consisting of natural rubber, synthetic polyisoprene with a cis-1,4 bond content (mol%) greater than 90% (more preferably greater than 98%), and mixtures of these elastomers. In a preferred embodiment, the isoprene elastomer content is in the range of 20 to 80 phr, preferably 30 to 70 phr, more preferably between 30 and 70 phr, and even more preferably between 35 and 65 phr.

[0014] The term "butadiene elastomer" means a diene elastomer that may be selected from the group consisting of butadiene homopolymers or copolymers, particularly polybutadiene (BR), various butadiene copolymers, and mixtures thereof, in known ways. Among butadiene copolymers, butadiene / styrene (SBR) or ethylene / butadiene (EBR) copolymers are particularly mentioned. Preferably, the butadiene elastomer may be cis-1,4-polybutadiene, particularly polybutadiene with a cis-1,4 bond content (mol%) greater than 90%, more preferably greater than 96%. In preferred embodiments, the butadiene elastomer content is in the range of 20-80 phr, preferably 30-70 phr, more preferably between 30 and 70 phr, and even more preferably between 35 and 65 phr. Preferably, in this advantageous embodiment, the elastomer matrix comprises at least one isoprene elastomer selected from the group consisting of natural rubber (NR), synthetic cis-1,4-polyisoprene (IR), particularly those having a cis-1,4 bond content (mol%) greater than 90% (more preferably greater than 98%), isoprene / styrene copolymer (SIR), isoprene / butadiene copolymer (BIR), isoprene / butadiene / styrene copolymer (SBIR), and mixtures of these elastomers, and at least one butadiene elastomer selected from the group consisting of polybutadiene (BR), particularly cis-1,4-polybutadiene having a cis-1,4 bond content (mol%) greater than 90% (more preferably greater than 96%), butadiene / styrene copolymer (SBR), ethylene / butadiene copolymer (EBR), and mixtures of these elastomers.

[0015] More preferably, the elastomer matrix comprises at least one isoprene elastomer selected from the group consisting of natural rubber (NR), synthetic cis-1,4-polyisoprene (IR), particularly those having a cis-1,4 bond content (mol%) greater than 90% (more preferably greater than 98%), and mixtures of these elastomers, and at least one butadiene elastomer which is polybutadiene (BR), particularly cis-1,4-polybutadiene having a cis-1,4 bond content (mol%) greater than 90% (more preferably greater than 96%). More preferably, the elastomer matrix comprises at least one isoprene elastomer which is natural rubber (NR), and at least one butadiene elastomer which is polybutadiene (BR), particularly cis-1,4-polybutadiene having a cis-1,4 bond content (mol%) greater than 90% (more preferably greater than 96%).

[0016] In a preferred embodiment, the elastomer matrix comprises at least one isoprene elastomer and at least one butadiene elastomer, wherein the isoprene elastomer content is in the range of 20 to 80 phr and the butadiene elastomer content is in the range of 20 to 80 phr. Preferably, in this embodiment, the isoprene elastomer content is in the range of 30 to 70 phr and the butadiene elastomer content is in the range of 30 to 70 phr. More preferably, the isoprene elastomer content is in the range of 30 to 70 phr and the butadiene elastomer content is in the range of 30 to 70 phr. Even more preferably, the isoprene elastomer content is in the range of 35 to 65 phr and the butadiene elastomer content is in the range of 35 to 65 phr. These content levels enable the acquisition of sidewalls with good tear strength. In a particularly advantageous embodiment, the elastomer matrix comprises at least one isoprene elastomer and at least one butadiene elastomer, wherein the isoprene elastomer is selected from the group consisting of natural rubber (NR), synthetic cis-1,4-polyisoprene (IR), and in particular, those having a cis-1,4 bond content (mol%) greater than 90% (more preferably greater than 98%), and the content of this isoprene elastomer is 20 to 80 phr, preferably 30 to 70 phr. Preferably between 30 and 70 phr, more preferably in the range of 35 to 65 phr, the butadiene elastomer is polybutadiene (BR), in particular cis-1,4-polybutadiene with a cis-1,4 linkage content (mol%) greater than 90% (more preferably greater than 96%), and the content of this butadiene elastomer is 20 to 80 phr, preferably 30 to 70 phr, more preferably between 30 and 70 phr, more preferably in the range of 35 to 65 phr.

[0017] Reinforcement filler The elastomer composition for the sidewall of the present invention comprises at least one reinforcing filler (i.e., one or more reinforcing fillers). It is possible to use any kind of "reinforcing" filler known for its ability to reinforce elastomer compositions, especially those used in tire manufacturing, such as organic fillers like carbon black, inorganic fillers like silica or alumina, or mixtures of these types of fillers. For the purposes of the present invention, the rubber powder described below is not considered a reinforcing filler in the meaning of the present invention. As a result, the content of rubber powder is not included in the content of the reinforcing filler and is a different content from the latter. Preferably, the content of the reinforcing filler is in the range of 5 to 70 phr, preferably 5 to 60 phr, more desirably 5 to 55 phr, even more desirably between 5 and 55 phr, very desirably between 10 and 50 phr, and most desirably in the range of 20 to 45 phr. With these contents, it becomes possible to obtain a sidewall having good tear strength characteristics.

[0018] Suitable carbon blacks include all carbon blacks, especially those conventionally used in tires. Among the latter, more specifically, reinforcing carbon blacks of series 100, 200 or 300, or carbon blacks of series 500, 600 or 700 (ASTM D - 1765 - 2017 grades), such as N115 black, N134 black, N234 black, N326 black, N330 black, N339 black, N347 black, N375 black, N550 black, N683 black and N772 black are mentioned. These carbon blacks can be used in isolated form, as commercial products, or in any other form, for example as a support for some rubber processing additives used. Carbon black may already be incorporated in diene elastomers, especially isoprene elastomers, for example in the form of masterbatches (see for example application WO97 / 36724 - A2 or WO99 / 16600 - A1).

[0019] The term “reinforcement inorganic filler” should be understood herein to mean any inorganic or mineral filler, known as “white filler,” “clear filler,” or even “non-black filler,” regardless of its color or origin (natural or synthetic), in contrast to carbon black, which can reinforce elastomer compositions intended for tire manufacturing by itself without the use of means other than intermediate coupling agents. In known ways, some reinforcement inorganic fillers can be characterized in particular by the presence of hydroxyl (-OH) groups on their surface. Silicate-containing mineral fillers, preferably silica (SiO2), or aluminum-type, particularly alumina (Al2O3), are especially suitable as reinforcing inorganic fillers. Any reinforcing silica known to those skilled in the art, especially one with a BET specific surface area and CTAB specific surface area of ​​450 m², is suitable. 2 Less than 30-400mg / g 2 / g, especially 60-300m 2 The BET specific surface area can be any precipitated silica or fumed silica within the range of / g. The BET specific surface area is determined by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" (vol. 60, page 309, February 1938), more specifically according to a method derived from standard NF ISO 5794-1, June 2010, Appendix E [multipoint (5-point) volumetric method - gas: nitrogen - degassing under vacuum: 160°C for 1 hour - relative pressure p / p0 range: 0.05~0.17]. The CTAB specific surface value of silica was determined according to standard NF ISO 5794-1, June 2010, Appendix G. This method is based on the adsorption of CTAB (N-hexadecyl-N,N,N-trimethylammonium bromide) on the "outer" surface of the reinforcing filler.

[0020] All types of precipitated silica, particularly highly dispersible precipitated silica (HDS), can be used. These precipitated silicas, whether highly dispersible or not, are well known to those skilled in the art. For example, it is possible to refer to the silica described in applications WO03 / 016215-A1 and WO03 / 016387-A1. Among commercially available HDS silicas, it is possible to use Evonik's UltraSil® 5000GR and UltraSil® 7000GR silica or Solvay's ZeoSil® 1085GR, ZeoSil® 1115MP, ZeoSil® 1165MP, ZeoSil® Premium 200MP and ZeoSil® HRS 1200MP silica. The physical state in which the reinforcing inorganic filler is provided—whether in the form of powder, micropearls, granules, beads, or other suitable densifying forms—is not important. Needless to say, the term “reinforcing inorganic filler” also refers to mixtures of various reinforcing inorganic fillers, particularly the silica mixtures mentioned above.

[0021] To bond reinforcing inorganic fillers, particularly silica, to diene elastomers, it is possible to use at least a bifunctional coupling agent (or binder) in known methods, which aims to provide a good correlation of chemical and / or physical properties between the inorganic filler (the surface of its particles) and the diene elastomer. In particular, at least a bifunctional organosilane or polyorganosiloxane having a first functional group that can interact with the inorganic filler and a second functional group that can interact with the diene elastomer is used. For example, such a bifunctional compound may include a first functional group containing a silicon atom that can interact with the hydroxyl group of the inorganic filler, and a second functional group containing a sulfur atom that can interact with the diene elastomer. Preferably, the organosilane is selected from the group consisting of organosilane polysulfides (symmetric or asymmetric), such as bis(3-triethoxysilylpropyl)tetrasulfide (abbreviated as TESPT), sold by Evonik under the name Si69, or bis(3-triethoxysilylpropyl) disulfide (abbreviated as TESPD), sold by Evonik under the name Si75, polyorganosiloxane, mercaptosilane, and blocked mercaptosilane, such as S-(3-(triethoxysilyl)propyl)octanthioate, sold by Momentive under the name NXTsilane. More preferably, the organosilane is an organosilane polysulfide.

[0022] According to an advantageous embodiment that can impart good tear strength properties and can be combined with other embodiments, the reinforcing filler mainly comprises carbon black, i.e., at least 51% by mass of carbon black relative to the total mass of the reinforcing filler. Optionally in this advantageous embodiment, the reinforcing filler may also comprise silica or another reinforcing inorganic filler. Preferably in this advantageous embodiment, the carbon black constitutes more than 60% by mass, preferably more than 80% by mass, more preferably more than 90% by mass, and preferably 100% by mass of the total mass of the reinforcing filler. Preferably, the content of the reinforcing filler in the elastomer composition is in the range of 5 to 70 phr, and carbon black accounts for more than 51% by mass, more than 60% by mass, preferably more than 80% by mass, more preferably more than 90% by mass, and preferably 100% by mass of the total mass of the reinforcing filler. More preferably, the content of the reinforcing filler in the elastomer composition is in the range of 5 to 60 phr, and carbon black is present in an amount of more than 51% by mass, more than 60% by mass, preferably more than 80% by mass, more preferably more than 90% by mass, and preferably 100% by mass of the total mass of the reinforcing filler.

[0023] More preferably, the content of the reinforcing filler in the elastomer composition is in the range of 5 to 55 phr, and the carbon black is present in an amount of more than 51% by mass, more than 60% by mass, preferably more than 80% by mass, more preferably more than 90% by mass, and preferably 100% by mass of the total mass of the reinforcing filler. More preferably, the content of the reinforcing filler in the elastomer composition is in the range of 5 to 55 phr, and the carbon black is present in an amount of more than 51% by mass, more than 60% by mass, preferably more than 80% by mass, more preferably more than 90% by mass, and preferably 100% by mass of the total mass of the reinforcing filler. More preferably, the content of the reinforcing filler in the elastomer composition is in the range of 10 to 50 phr, and the carbon black is in the range of more than 51% by mass, more than 60% by mass, preferably more than 80% by mass, more preferably more than 90% by mass, and preferably 100% by mass of the total mass of the reinforcing filler. More preferably, the content of the reinforcing filler in the elastomer composition is in the range of 20 to 45 phr, and the carbon black is present in an amount of more than 51% by mass, more than 60% by mass, preferably more than 80% by mass, more preferably more than 90% by mass, and preferably 100% by mass of the total mass of the reinforcing filler.

[0024] rubber powder The sidewall elastomer compositions useful within the scope of the present invention also contain rubber powder. The powders usable within the scope of this invention exist in granular form and are processed into rubber sheets as needed. Generally, these powders are obtained by grinding or micronizing vulcanized elastomer compositions already used in first applications, such as tires, shoe soles, and seals. These powders are products of the recycling of these materials. All rubber powders produced from recycled elastomer compositions, especially those produced from worn tires, are suitable. As is known, rubber powder can be obtained by breaking down worn tires or other rubber into granules, and then removing reinforcing materials such as steel or textile fibers, and any other contaminants such as sand, glass, or stone, from these granules.

[0025] For example, rubber powder was prepared by cryogenic grinding of a worn tire by the method described in reference US7445170, which includes a series of independent steps: granulation, separation of metal and textile reinforcements, cooling, and micronization, in order to obtain a coarse distribution of micron particles (also called fine particles) of the vulcanization mixture. This micronization may be carried out using a conical impact mill as described in reference US7861958. The cryogenically ground input is placed in a mill (e.g., a Netsch CUM150 mill or an Alpine CW250 mill can be used) and then transferred to a rotor that rotates at high speed by gravity. In this way, the cryogenically ground input is sprayed multiple times against the walls of the rotor chamber to achieve micronization. These particles may then be passed through a series of two vibrating screens of the same size to separate the last elements that do not consist of the vulcanization mixture. A coarse distribution of micron particles of the vulcanization mixture is obtained. The term “fine particles” is understood to mean particles whose size, i.e., their diameter in the case of spherical particles, or their maximum dimension in the case of unequal particles, is tens or hundreds of micrometers. The size of minute particles can be determined by techniques known to those skilled in the art, such as microscopic examination. In the embodiment, the rubber powder is not further processed and is simply pulverized / micronized rubber. It is also a known practice to subject the rubber powder to a treatment for modification. This treatment may consist of chemical functionalization or desulfurization modification. This may also be a thermomechanical, thermochemical, or biological treatment.

[0026] According to an advantageous embodiment that imparts good tear strength characteristics to the sidewall and can be combined with other embodiments, the rubber powder is a powder that has not undergone any modification by treatment selected from the group consisting of thermal, mechanical, biological and chemical treatments and combinations thereof. According to an advantageous embodiment that imparts good tear strength characteristics to the sidewall and can be combined with other embodiments, the rubber powder may have a particle size distribution such that less than 1 mass of particles that do not pass through a 600 μm sieve and less than 10% by mass of particles that do not pass through a 105 μm sieve relative to the total mass of particles in the rubber powder; more preferably, a particle size distribution such that less than 1% by mass of particles that do not pass through a 600 μm sieve and less than 10% by mass of particles that do not pass through a 149 μm sieve; even more preferably, a particle size distribution such that less than 1% by mass of particles that do not pass through a 600 μm sieve and less than 10% by mass of particles that do not pass through a 177 μm sieve relative to the total mass of particles in the rubber powder. The distribution of rubber powder particles is measured in accordance with the standard ASTM D5644-01:2013.

[0027] According to an advantageous embodiment that imparts good tear strength characteristics to the sidewall and can be combined with other embodiments, the rubber powder may have a particle size distribution such that it includes particles that do not pass through a 250 μm sieve and particles that do not pass through a 177 μm sieve, with respect to the total mass of fine particles in the rubber powder being less than 1 mass. To obtain such rubber powder having such a distribution, an additional sieving step was performed according to a size criterion. Sieving can be performed by various techniques known to those skilled in the art (vibration, centrifugation, suction). Preferably, this sieving step is performed using a series of sieves stacked in size order (e.g., sieves with calibrated mesh sizes, such as commercially available products from Gericke). Thus, larger particles remain on the sieve, while smaller particles pass down to the next sieve. Those skilled in the art will understand that the distribution considered below may consist of all particles passing through a given sieve or all particles held between two sieves. Rubber powder is typically made from components obtained from elastomer compositions used in tires. In other words, rubber powder is typically made from a composition based on at least one elastomer and at least one filler, particularly a reinforcing filler. It may also typically contain all the components used in elastomer compositions, especially those for tire manufacturing, such as plasticizers, antioxidants, and vulcanizing additives. These components have been described above and will not be repeated here for brevity.

[0028] Therefore, the rubber powder contains at least one diene-based elastomer and at least one carbon black. The diene-based elastomer is preferably at least 30% by mass, more preferably at least 35% by mass, and even more preferably at least 40% by mass, relative to the mass of the rubber powder, and the proportion is determined in accordance with the standard ASTM E1131-03. The carbon black is preferably present in the rubber powder in an amount ranging from 20% to 40% by mass, more preferably 25% to 35% by mass, relative to the mass of the rubber powder, and the proportion is determined according to the method described above. The mass fraction of carbon black is measured by thermogravimetric analysis (TGA) in accordance with standard NF T-46-07 using a Mettler-Toledo instrument, model "TGA / DSC1". Approximately 20 g of the sample is introduced into the thermal analyzer and then subjected to a temperature program of 25-600°C (thermal decomposition phase) under an inert atmosphere, followed by 400-750°C (oxidative phase) under an oxidizing atmosphere. The mass of the sample is measured continuously throughout the temperature program. The organic matter content corresponds to the mass loss measured during the thermal decomposition phase relative to the initial mass of the sample. The carbon black content corresponds to the mass loss measured during the oxidative phase relative to the initial mass of the sample.

[0029] Those skilled in the art will know how to adapt the rubber powder content to the needs of the present invention. Rubber powders usable within the scope of the present invention are commercially available from suppliers such as Lehi Technologies. Preferably, the rubber powder content is in the range of 2 to 35 phr, more preferably between 5 and 33 phr, more preferably between 6 and 32 phr, more preferably between 7 and 31 phr, and even more preferably between 8 and 30 phr. According to an advantageous embodiment that imparts good tear strength characteristics to the sidewall, the mass ratio of the content of rubber powder represented by phr to the content of reinforcing filler represented by phr is in the range of 0.25 to 1.50, preferably 0.25 to 1.30, more preferably 0.25 to 1.10, and even more preferably 0.28 to 1.03. Crosslinked system In the embodiment, the elastomer composition includes at least one crosslinking system. The crosslinking system can be any type known to those skilled in the art in the field of elastomer compositions for tires. The crosslinking system may be based in particular on sulfur and / or peroxide and / or bismaleimide.

[0030] Preferably, the crosslinking system is sulfur-based, also known as the vulcanizing system. Sulfur can be provided in any form, particularly as molecular sulfur or a sulfur donor. At least one vulcanization accelerator is also preferably present, and optionally and preferably, a variety of known vulcanizing activators may be used, such as zinc oxide, stearic acid or equivalent compounds, such as transition metal salts and multiple salts of stearic acid, guanidine derivatives (particularly diphenylguanidine), or known vulcanization retarders. As accelerators, any compound that can act as an accelerator for vulcanizing diene elastomers in the presence of sulfur, particularly thiazole type and derivatives thereof, or as an accelerator of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea, and xanthanthate type may be used. Sulfur may be used in a desirable content of 0.5 to 12 phr, particularly within the range of 0.7 to 7 phr. The vulcanization accelerator may be used in a desirable content of 0.5 to 10 phr, more preferably within the range of 0.5 to 5.0 phr.

[0031] Other additives The elastomer composition may also contain all or some of the common additives and processing aids known to those skilled in the art and commonly used in elastomer compositions, particularly for the manufacture of tires, especially sidewalls, such as plasticizers (such as plasticizing oils and / or plasticizing resins), non-reinforcing fillers, dyes, protective agents, ozone-proof waxes, chemical ozone-proofing agents, antioxidants, anti-fatigue agents, or reinforcing resins (for example, those described in application WO02 / 10269). plasticizer In embodiments that allow the sidewall to be made softer and thus less susceptible to tearing, the elastomer composition may contain at least one plasticizer (i.e., one or more plasticizers). In addition to improving tear strength, the plasticizer helps reduce hysteresis in the tire sidewall and thus reduce the tire's rolling resistance. In any preferred embodiment, the plasticizer is selected from the group consisting of plasticizing oils, plasticizing resins having a high Tg, and mixtures thereof. According to an advantageous embodiment that imparts good tear strength properties to the sidewall and can be combined with other embodiments, the elastomer composition comprises a plasticizer, the plasticizer content of which is in the range of 2 to 28 phr, more preferably 7 to 24 phr, and even more preferably 10 to 20 phr.

[0032] Any extender oil, whether aromatic or non-aromatic, whose plasticizing properties toward the elastomer matrix are known, may be used. These oils, which are more or less viscous at room temperature (23°C), are liquid (for the record, substances capable of taking the shape of their containers) in contrast to hydrocarbon resins, which have particularly high Tg and are essentially solid at room temperature and atmospheric pressure. Plasticizing oils generally have a glass transition temperature (Tg) of less than -20°C, preferably less than -40°C. The Tg of plasticizing oils is measured in accordance with the standard ASTM D3418 (2008). In some embodiments, plasticizing oils selected from the group consisting of naphthenic oil (high or low viscosity, especially hydrogenated or unhydrogenated), paraffinic oil, DAE (distilled aromatic extract) oil, polyolefin oil, MES (medium extraction solvate) oil, TDAE (treated distilled aromatic extract) oil, RAE (residual aromatic extract) oil, TRAE (treated residual aromatic extract) oil, and SRAE (safe residual aromatic extract) oil, mineral oil, vegetable oil, ether-based plasticizers, ester-based plasticizers, phosphate-based plasticizers, sulfonate-based plasticizers, and mixtures thereof are particularly suitable as plasticizers for elastomer compositions.

[0033] According to an advantageous embodiment that imparts good tear strength characteristics to the sidewall and can be combined with other embodiments, the plasticizer is an oil selected from the group consisting of MES oil, TDAE oil, RAE oil, TRAE oil, SRAE oil, mineral oil, vegetable oil, and mixtures thereof of plasticizing oils. By definition, hydrocarbon resins with high Tg are solid at room temperature and ambient pressure (23°C, 1 atm), while plasticizing oils are liquid at room temperature, and hydrocarbon resins with low Tg are viscous at room temperature. Hydrocarbon resins, also known as hydrocarbon plasticizers, are polymers well known to those skilled in the art, which are essentially based on carbon and hydrogen but may contain other types of atoms, such as oxygen, and can be used particularly as plasticizers or tackifiers in polymer matrices. They are essentially miscible (i.e., compatible) to act as true diluents in the amounts used with the polymer composition in question. These are described, for example, in the study entitled "Hydrocarbon Resins" by R. Mildenberg, M. Zander, and G. Collin (New York, VCH, 1997, ISBN 3-527-28617-9), Chapter 5 of which is directed towards these applications, particularly in the field of tire rubber (5.5. "Rubber Tires and Mechanical Goods"). In known ways, these hydrocarbon resins may also be described as thermoplastic resins, in the sense that they soften when heated and are therefore moldable.

[0034] The softening point of hydrocarbon resins is measured according to standard ISO 4625 ("ring and ball" method). The Tg of hydrocarbon resins is measured according to standard ASTM D3418 (2008). The macrostructure (Mw, Mn, and PDI) of hydrocarbon resins is determined by size exclusion chromatography (SEC): solvent is tetrahydrofuran, temperature is 35°C, concentration is 1 g / l, flow rate is 1 ml / min, solution filtered through a filter with a porosity of 0.45 μm before injection, Moore calibration with polystyrene standard, setup of three Waters columns in series (Styragel HR4E, HR1, and HR0.5), detection by differential refractometer (Waters 2410) and its associated operating software (Waters Empower). Hydrocarbon resins can be aliphatic, aromatic, or aliphatic / aromatic, i.e., based on aliphatic monomers and / or aromatic monomers. They may be natural or synthetic, and may be petroleum-based (in the case of petroleum-based, also known as petroleum resins) or not. Examples of suitable aromatic monomers include styrene, α-methylstyrene, indene, ortho-, meta-, para-methylstyrene, vinyltoluene, para-tert-butylstyrene, methoxystyrene, chlorostyrene, vinylmesitylene, divinylbenzene, vinylnaphthalene, and any vinyl aromatic monomer derived from C9 cut (or more generally C8-C10 cut). Preferably, the vinyl aromatic monomer is styrene or a vinyl aromatic monomer derived from C9 cut (or more generally C8-C10 cut). Preferably, the vinyl aromatic monomer is a small amount of monomer in the copolymer under consideration and is expressed as a mole fraction.

[0035] In some embodiments, the hydrocarbon plasticizer resin is selected from the group consisting of homopolymer or copolymer resins of cyclopentadiene (abbreviated as CPD) or dicyclopentadiene (abbreviated as DCPD), terpene homopolymer or copolymer resins, terpene phenol homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins, C9-cut homopolymer or copolymer resins, α-methylstyrene homopolymer and copolymer resins, and mixtures of these resins that are particularly suitable as plasticizers for elastomer compositions. The term "terpene" herein refers to a combination of α-pinene monomer, β-pinene monomer, and limonene monomer in known ways, preferably limonene monomer, which exists in known ways in the form of three possible isomers: L-limonene (levorotatory enantiomer), D-limonene (dextrorotatory enantiomer), or dipentene, which is a racemic mixture of the dextrorotatory and levorotatory enantiomers. Among the hydrocarbon-based plasticizers mentioned above, homopolymer or copolymer resins of α-pinene, β-pinene, dipentene, or polylimonene are particularly mentioned.

[0036] Most preferably, the hydrocarbon resin is composed primarily of units derived from C5 monomers. The term "C5 monomer" is conventionally understood by those skilled in the art to mean monomers derived from C4-C6 oil cuts. Suitable examples include 1,3-pentadiene, pentene, cyclopentadiene, cyclopentene, piperine, and isoprene, which can be cis and trans. In addition to these units, this "C5" resin, composed primarily of units derived from C5 monomers, may also contain a small number of aliphatic units, aromatic units, or aliphatic / aromatic units, i.e., units based on aliphatic monomers other than C5 and / or aromatic monomers. Preferably, the hydrocarbon resin that may be used is composed primarily of units derived from C5 monomers, with an aromatic proton content of less than 20%, preferably less than 15%, and more preferably in the range of 7-15%, preferably 9-13%. Also preferably, this hydrocarbon resin has an ethylenic proton content of less than 15%, preferably less than 7%, and more preferably less than 5%. Preferably, the C5 hydrocarbon resin has a glass transition temperature (Tg) in the range of 30°C to 80°C, preferably 40°C to 60°C. The C5 hydrocarbon resin has an average molecular weight (Mn) in the range of 500 g / mol to 3000 g / mol, preferably 700 to 2000 g / mol. Preferably, the hydrocarbon resin has a polydispersity index (PI) in the range of 1 to 4, preferably 1.5 to 3.5, more preferably 1.7 to 3. Numerous hydrocarbon resins are commercially available. These resins may have different properties depending on the supplier, particularly in terms of chemical composition, Tg, Mn, aromatic or ethylenically proton content, or PI. The macrostructure (Mw, Mn, PI, and Mz) of hydrocarbon resins is determined by size exclusion chromatography (SEC) based on standards ISO 16014 (Determination of average molecular weight and molecular weight distribution of polymers using size exclusion chromatography), ASTM D5296 (Average molecular weight and molecular weight distribution of polystyrene by high-speed size exclusion chromatography), and DIN 55672 (Size exclusion chromatography). Aromatic proton content (%AH) and ethylenic proton content (%EH) are measured by 1H NMR.This determination is performed on all detected signals. Therefore, the results obtained are expressed as a percentage of the peak region. C5 resins are commercially available, for example, from Eastman under the trade names Piccotac 1105 or Impera R1507, from Exxon under the trade name Escorez 1102, from Kolon under the trade name Hikorez A1100, or from Clay Valley Total under the trade name Wingtack 98. C5-C9 resins are commercially available, for example, from Exxon under the trade name Oppera 373, from Eastman under the trade name Piccotac 8090, or from Clay Valley Total under the trade name Wingtack STS.

[0037] When the plasticizer is a mixture of hydrocarbon resin and oil, the plasticizer content, in the above ratio calculation, is the sum of the hydrocarbon resin content (expressed in phr) and the oil content (expressed in phr). According to an advantageous embodiment for imparting good tear strength properties to the sidewall, the elastomer composition contains a plasticizer, and the mass ratio of the content of the reinforcing filler, represented by phr, to the content of the plasticizer, represented by phr, is 4.50 or less, preferably 4.00 or less, and more preferably 3.75 or less. According to an advantageous embodiment for imparting good tear strength properties to the sidewall, the elastomer composition contains a plasticizer, and the mass ratio of the content of the reinforcing filler, represented by phr, to the content of the plasticizer, represented by phr, is 1.00 or more, preferably 2.00 or more, and more preferably 2.42 or more.

[0038] Ozone-proof wax Ozone-protective waxes are known and may be, for example, paraffin wax, microcrystalline wax, or a mixture of paraffin wax and microcrystalline wax. These mainly consist of a mixture of linear and nonlinear alkanes (isoalkanes, cycloalkanes, branched alkanes) resulting from the refining of oils containing chains of at least 20 carbon atoms or catalytic hydrogenation with carbon monoxide (Fischer-Tropsch process). For example, all known ozone-protective waxes, including natural waxes such as candelilla wax or carnauba wax, may be used. Furthermore, these waxes may be used as a blend. Ozone-blocking waxes are commercially available, for example, Varazon 4959, Varazon 6500, and Varazon 6810 from Sasol, Ozoace 0355 from Nippon Seiro Co., Ltd., Negozone 9343 from H&R, and H3841 from Yangoo Huatai.

[0039] According to a preferred embodiment of the elastomer composition, which may be used within the scope of the present invention and can be combined with embodiments of the present invention, the wax content is in the range of 1 to 3 phr, more preferably in the range of 1.2 phr to 2.8 phr. A method for preparing an elastomer composition usable within the scope of the present invention. Elastomer compositions usable within the scope of the present invention are manufactured in a suitable mixer using a two-step sequential preparation well known to those skilled in the art: - A first stage of thermomechanical processing or kneading (known as the "non-productive" stage) can be carried out in a single thermomechanical step, during which various other optional additives, except for the necessary components, particularly the elastomer matrix, reinforcing fillers, rubber powders, and crosslinking systems, are introduced into a suitable mixer, such as a standard internal mixer (e.g., a "Banbury" type). The non-productive stage may be carried out at high temperatures, generally for 2 to 10 minutes, with a maximum temperature in the range of 110°C to 200°C, preferably 130°C to 185°C; - The mixture obtained during the first non-productive stage is cooled to a low temperature, usually below 120°C, for example, in the range of 40°C to 100°C, and then a second stage of mechanical processing (known as the "productive" stage) is carried out in an external mixer such as an open mill. A crosslinking system, preferably a vulcanizing system (in particular a vulcanizing agent, a vulcanization accelerator, and optionally a vulcanization retarder if present) is then incorporated, and the combined mixture is then mixed for several minutes, for example, 5 to 15 minutes.

[0040] The final elastomer composition thus obtained can then be calendered, for example, in the form of sheets or specks, particularly for laboratory characterization, or extruded into the form of rubber semi-finished products (or profile elements) that can be used for tire sidewalls. The elastomer composition may be in an unprocessed state (before crosslinking or vulcanization) or a cured state (after crosslinking or vulcanization), and may be a semi-finished product that can be used in tires. Crosslinking of elastomer compositions, particularly vulcanization, can be carried out by methods known to those skilled in the art, for example, under pressure and at temperatures in the range of 130°C to 200°C. The tire is intended for passenger vehicles as defined in the 2021 ETRTO Standard Manual. Such a tire has a cross section in a meridian section plane characterized by a section height H and a nominal section width S as defined in the 2021 ETRTO Standard Manual, and therefore, optionally, the H / S ratio, expressed as a percentage, is 90 or less, preferably 50 or less, more preferably 40 or less, and 20 or more, preferably 25 or more, and the nominal section width S is 155 mm or more, preferably 205 mm or more, more preferably 225 mm or more, and 385 mm or less, preferably 335 mm or less. Furthermore, the diameter at the flange D that defines the diameter of the tire mounting rim is 12 inches or more, preferably 16 inches or more, and 24 inches or less.

[0041] Optionally, the tire includes the bead or at least one carcass layer fixed to each bead, and includes carcass reinforcements extending radially in the sidewall or within each sidewall, axially within the crown, and radially toward the interior of the crown reinforcement. Optionally, the carcass layer or each carcass layer may be axially separated by two axle ends and include a carcass reinforcing element that extends axially in the principal direction from one axle end of the carcass layer to the other, which may, and preferably, form an absolute angle of 60° or more, more preferably 80° to 90°, with respect to the circumferential direction of the tire. In certain variations, the carcass reinforcement includes one carcass layer fixed to the bead or each bead, extending radially within each sidewall, axially within the crown, and radially toward the interior of the crown reinforcement. The presence of this one carcass layer fixed to the bead or each bead is understood to mean that the carcass reinforcement is not reinforced by any reinforcing elements other than the carcass layer, and does not include any layers fixed to this bead or each bead. Reinforcing elements of such reinforcing layers excluded from the carcass reinforcement of the tire include metal reinforcing elements and woven reinforcing elements. The carcass reinforcement is very preferably formed by one carcass layer. More preferably, the tire further lacks the sidewall reinforcement layers as defined below herein.

[0042] In a first configuration of a carcass reinforcement comprising one carcass layer, the carcass layer fixed to each bead wraps around the circumferential reinforcement element of each bead such that the axially inward portion of the carcass layer fixed to each bead is axially positioned toward the inside of the axially outward portion of the carcass layer fixed to each bead. In a second configuration of a carcass reinforcement comprising one carcass layer, each bead includes an axial inner circumferential reinforcing element axially positioned toward the inside of the carcass layer and an axial outer circumferential reinforcing element axially positioned toward the outside of the carcass layer, as described, for example, in WO2021 / 123522. In certain deformations, the carcass reinforcement includes first and second carcass layers that are fixed to the bead or each bead and extend radially within each sidewall and radially inward toward the interior of the crown reinforcement within the crown. In the first configuration of the carcass reinforcement, which includes first and second carcass layers, the first carcass layer wraps around the circumferential reinforcing elements of each bead such that the axially inward portion of the first carcass layer is axially positioned toward the inside of the axially outward portion of the first carcass layer, and each axial end of the first carcass layer is radially positioned toward the outside of each circumferential reinforcing element, and each axial end of the second carcass layer is radially positioned toward the inside of each axial end of the first layer.

[0043] In the first variation of the first configuration, each axial end of the second carcass layer is positioned axially between the axially inward and outward portions of the first carcass layer. In this variation, the second carcass layer is positioned radially toward the outside of the first carcass layer within the crown. In the second variation of the first configuration, each axial end of the second carcass layer is axially positioned toward the inside of each axially inward portion of the first carcass layer. In this variation, the second carcass layer is radially positioned toward the inside of the first carcass layer within the crown, and axially positioned toward the inside of the first carcass layer within each sidewall. Such arrangement of the first and second carcass layers in the first and second deformations makes it possible to obtain an effective mechanical connection between the first and second carcass layers, thereby reducing the shear between the first and second carcass layers. Subsequently, considering that shear is particularly pronounced under high loads, this reduces energy loss and increases tire temperature.

[0044] Furthermore, due to the unique arrangement of the first and second carcass layers, surprisingly, a tire is obtained that exhibits optimal energy loss and optimal operating temperature in the sidewall at pressures below the recommended pressure for tires of the same size in its standard load or extra load specifications, especially under high loads. This is all the more surprising considering that the unique arrangement of the first and second carcass layers allows for a reduction in energy loss in one area of ​​the tire, in this case the bead or near the bead, but away from the bead, in this case the sidewall. It has been found that the unique arrangement of the carcass reinforcements, namely the fact that each axle end of the second carcass layer is positioned axially between the axially inward and outward portions of the first carcass layer, or axially toward the inside of the axially inward portion of the first carcass layer, allows for a reduction in the tension difference between the first and second carcass layers. In fact, as the reduction in the tension difference between the first and second carcass layers increases, the shear generated between these first and second carcass layers decreases, resulting in less energy loss. In the third variation of the first configuration, each axial end of the second carcass layer is axially positioned toward the outside of each axially outward portion of the first carcass layer. In this variation, the second carcass layer is radially positioned toward the outside of the first carcass layer within the crown, and axially positioned toward the outside of the first carcass layer within each sidewall.

[0045] This third modification is particularly advantageous for tires with relatively high sidewalls. Specifically, for high-load capacity tires with relatively large sidewall heights, the tension at the edges of the first carcass layer is high. Therefore, unlike the arrangements described in the first and second configurations, it is preferable to assume that each axle end of the second carcass layer is axially positioned toward the outside of each axially outward portion of the first carcass layer. By using such a carcass reinforcement arrangement, the tension at the edges of the first carcass layer will be reduced to a lower level. In a second configuration of the carcass reinforcement including first and second carcass layers, using each bead including at least first and second circumferential reinforcing elements, portions of each of the first and second carcass layers are axially positioned between at least two of the first and second circumferential reinforcing elements. Such configurations are described in particular in WO2021 / 123522. Regardless of the number of carcass layers in each first configuration, in a certain deformation, each axle end of this carcass layer or the first carcass layer is positioned radially toward the inside of the tire equator, and more preferably further positioned within a radial distance of 30 mm from the radial inner end of each circumferential reinforcing element of each bead.

[0046] By positioning each axle end of the enclosed carcass layer toward the inside of the tire's equator, the mass of the carcass reinforcement is significantly reduced. Furthermore, the vast majority of rims currently used for passenger vehicle tires have a J-shaped flange that is less than 30 mm in height in all cases. A very favorable positioning of each axle end in a region substantially radially corresponding to the rim flange makes it possible to mechanically protect each axle end. Specifically, if each axle end is positioned radially excessively high beyond each circumferential reinforcing element of each bead, i.e., at a radial distance strictly exceeding 30 mm from the radially inner end of each circumferential reinforcing element, each axle end lies in a flexible region of the tire that is exposed to excessively high stresses, and these stresses are extremely high in the case of high-load capacity tires. Regardless of the number of carcass layers in each first configuration, in other variations, each axle end of this carcass layer or the first carcass layer is radially positioned toward the outside of the tire's equator. Advantageously, in these other embodiments, it is highly desirable that each axle end of this carcass layer or the first carcass layer be axially positioned toward the inside of the axle end of this crown layer or at least one crown layer of the crown reinforcement. In further variations, the carcass reinforcement includes one carcass layer fixed to each bead and extending radially within each sidewall and axially within the crown towards the interior of the crown reinforcement, and the tire includes a sidewall reinforcement layer extending at least radially within each sidewall, and has the following: - The radial inner end of the tire, which is positioned radially toward the inside of the equator, and - The radially outer edge of the tire, positioned radially toward the outside of the equator.

[0047] Furthermore, in these other variations, the present invention makes it possible to avoid the use of a second carcass layer that extends radially toward the interior of the crown reinforcement, particularly axially within the crown. As a result, the sidewall reinforcement layer is not continuous below the crown of the tire. The sidewall reinforcement layer is not fixed to the tire bead. Therefore, the radial inner end of the sidewall reinforcement layer is positioned radially toward the outside of the bead. In some advantageous embodiments, the crown reinforcement comprises a machined reinforcement having at least one machined layer and a hoop reinforcement having at least one hoop layer, wherein the hoop reinforcement is radially positioned toward the outside of the machined reinforcement. Optionally, the hoop layer or each hoop layer is axially separated by two shaft ends. The hoop layer or each hoop layer includes one or more hoop reinforcing elements spirally wound around the hoop layer in such a manner that they extend axially in the principal direction from one shaft end of the hoop layer to the other. Optionally, and preferably, the principal direction forms an angle with the circumferential direction of the tire at an absolute value of 10° or less, preferably 7° or less, and more preferably 5° or less. Optionally, this processed layer or each processed layer is axially separated by two shaft ends. This processed layer or each processed layer optionally includes a processed reinforcement element that extends axially from one shaft end to the other, substantially parallel to each other, in the principal direction which forms an angle with the circumferential direction of the tire and in an absolute value of more than 10°, preferably 15° to 50°, and more preferably 25° to 45°.

[0048] Preferably, this hoop or each hoop, processing, and carcass reinforcing element is a filamentous reinforcing element. The term "reinforcement element" refers to an element that provides mechanical reinforcement to the polymer matrix into which it is intended to be embedded. Preferably, each reinforcing element is filamentous, meaning that each reinforcing element, regardless of its shape—circular, elliptical, oblong, polygonal, and especially rectangular, square, or oval—has a length at least 10 times greater than the maximum dimension of its cross-section. In the case of a rectangular cross-section, the filamentous reinforcing element is strip-shaped. In an optional but advantageous embodiment, the tire has a sidewall height H defined as H = SW × AR / 100, where SW is the nominal section width, AR is the nominal aspect ratio of the tire, and the load index LI satisfies 0.72 ≤ H / LI ≤ 0.98, preferably 0.82 ≤ H / LI ≤ 0.98, and more preferably 0.82 ≤ H / LI ≤ 0.92, with SW, AR, and LI defined in accordance with the 2021 ETRTO Standards Manual. The nominal section width SW and nominal aspect ratio AR are derived from the size markings stamped on the tire sidewall, for example, in accordance with the 2021 ETRTO Standards Manual. Such an H / LI ratio is characteristic of a tire where the sidewall is considerably more flexible, considering the height of the sidewall relative to the maximum load it can withstand. The present invention is given merely as a non-limiting example and will be better understood by reading the following description, which is made with reference to the drawings. [Brief explanation of the drawing]

[0049] [Figure 1] This is a diagram of a tire according to the first embodiment of the present invention, in a meridian section plane parallel to the rotation axis of the tire. [Figure 2] These are diagrams of tires according to the second, third, fourth, fifth, and sixth embodiments of the present invention, similar to Figure 1. [Figure 3]These are diagrams of tires according to the second, third, fourth, fifth, and sixth embodiments of the present invention, similar to Figure 1. [Figure 4] These are diagrams of tires according to the second, third, fourth, fifth, and sixth embodiments of the present invention, similar to Figure 1. [Figure 5] These are diagrams of tires according to the second, third, fourth, fifth, and sixth embodiments of the present invention, similar to Figure 1. [Figure 6] These are diagrams of tires according to the second, third, fourth, fifth, and sixth embodiments of the present invention, similar to Figure 1. [Modes for carrying out the invention]

[0050] The reference coordinate systems X, Y, and Z, corresponding to the normal axial (Y), radial (Z), and circumferential (X) directions of the tire, are shown in the drawings related to the tire. Figure 1 shows a tire according to the present invention, indicated by general reference number 10. Tire 10 has a substantially toric shape with respect to a rotation axis substantially parallel to the axial Y. Tire 10 is for passenger vehicles and is size 255 / 35 R18. Tire 10 is a high-load capacity type according to the 2021 ETRTO standard manual. In various figures, tire 10 is shown as new, i.e., unused. Tire 10 has a sidewall height H defined as H = SW × AR / 100, where SW is the nominal section width, in this case 255, and AR is the nominal aspect ratio of the tire, in this case 35. The load index LI is equal to 98 in this case. Thus, the load index LI satisfies 0.72 ≤ H / LI ≤ 0.98, preferably 0.82 ≤ H / LI ≤ 0.98, and more preferably 0.82 ≤ H / LI ≤ 0.92, in which case H / LI = 0.91. SW, AR, and LI are defined in accordance with the 2021 edition of the ETRTO standards manual.

[0051] The tire 10 includes a crown 12 with a tread 14 intended to contact the ground during driving, and a crown reinforcement 16 extending into the crown 12 in the circumferential direction X. The tire 10 also includes an airtight inner liner 18, which is impermeable to the expansion gas and is intended to separate the internal cavity intended to be pressurized with the expansion gas when the tire 10 is fixed to a mounting support, such as a rim, from the mounting support of the tire 10. The airtight inner liner 18 has an inner surface 19 of the tire 10. The tire 10 also has an outer surface 31. The crown reinforcement 16 includes a processed reinforcement 20 and a hoop reinforcement 22, each of which reinforcements 20 and 22 includes at least one crown layer. The processed reinforcement 20 includes at least one processed layer, in which case it includes two processed layers, including a radially inward processed layer 24 radially positioned toward the inside of a radially outward processed layer 26. The hoop reinforcement 22 includes at least one hoop layer, in this case one hoop layer 28. The crown reinforcement 16 is positioned radially toward the inside of the tread 14. In this case, the hoop reinforcement 22, in this case the hoop layer 28, is positioned radially toward the outside of the processed reinforcement 20, and is therefore inserted radially between the processed reinforcement 20 and the tread 14.

[0052] The tire 10 includes two sidewalls 30 that radially connect the crown 12 toward the inside. The tire 10 also has two beads 32 radially inside the sidewalls 30. Each sidewall 30 connects each bead 32 to the crown 12. Each sidewall 30 has a portion of its outer surface 31. Each sidewall 30 contains an elastomer composition as described above and in the following embodiments. The tire 10 includes a carcass reinforcement 34. The crown reinforcement 16 is positioned radially between the tread 14 and the carcass reinforcement 34. The carcass reinforcement 34 includes at least one carcass layer 36, in this case one carcass layer 36 fixed to each bead 32. The carcass layer 36 extends radially within each sidewall 30, axially within the crown 12, and radially into the interior of the crown reinforcement 16. For the purpose of fixing the carcass layer 36, the tire 10 includes an axial inner circumferential reinforcing element 38 axially positioned toward the inside of the carcass layer 36 and an axial outer circumferential reinforcing element 40 axially positioned toward the outside of the carcass layer 36. Here, each reinforcing element 38, 40 includes a continuous filament-like reinforcing element that is wound several times in the circumferential direction, for example, as described in WO2021 / 123522.

[0053] In this case, the crown reinforcement 16 includes two axial ends 161 and 162 that coincide with the ends of the widest layer in the axial direction of the crown reinforcement 16. Each processed layer 24, 26, hoop layer 28, and carcass layer 36 includes a polymer matrix, in this case an elastomer matrix, into which one or more reinforcing elements, in this case filamentous reinforcing elements, are embedded in the corresponding layer. The matrix is ​​called a polymer matrix because it is based on a polymer composition, which probably includes one or more polymers selected from, for example, thermoplastic polymers, thermosetting polymers, elastomers, and thermoplastic elastomers, and also includes fillers and other components commonly used in the field of tire compositions, particularly compositions for embedding reinforcing elements. The hoop reinforcement 22, in this case the hoop layer 28, is axially separated by two shaft ends, in this case shaft ends 161 and 162. The hoop reinforcement 22 includes one or more filamentary hoop reinforcement elements wound spirally around the hoop layer 28 so as to extend axially from one shaft end to the other in the main direction D0. The main direction D0 forms an angle AF with the circumferential direction X of the tire 10 at an absolute value of 10° or less, preferably 7° or less, and more preferably 5° or less. In this case, AF = -5°.

[0054] The radially inward-facing machined layer 24 is axially separated by two shaft ends. The radially inward-facing machined layer 24 includes filamentous machined reinforcing elements that extend axially from one shaft end to the other, substantially parallel to each other in the principal direction D1. Similarly, the radially outward-facing machined layer 26 is axially separated by two shaft ends. The radially outward-facing machined layer 26 includes filamentous machined reinforcing elements that extend axially from one shaft end to the other, substantially parallel to each other in the principal direction D2. Each principal direction D1 and D2 forms angles AT1 and AT2, respectively, opposite to the circumferential direction X of the tire 10. Each principal direction D1 and D2 forms angles AT1 and AT2, respectively, with the circumferential direction X of the tire 10, with an absolute value of more than 10°, preferably 15° to 50°, and more preferably 25° to 45°. In this case, AT1 = -33° and AT2 = +33°. The carcass layer 36 is axially divided by two axle ends 361 and 362. The carcass layer 36 includes filamentous carcass reinforcing elements that extend axially from one axle end 361 or 362 to the other in the circumferential direction X of the tire 10 and in the principal direction D3, which forms an angle AC, in absolute value of 60° or more, preferably 80° to 90°, in this case AC = +90°. Each filamentous hoop reinforcing element, processed reinforcing element, and carcass reinforcing element is identical to those described, for example, in application WO2021 / 123522.

[0055] The tread 14 includes a tread surface 38 in which the tread 14 contacts the ground. The tread 14 includes several circumferential cuts, in this case several circumferential grooves, including first, second, third and fourth circumferential cuts designated by reference numbers 52, 54, 56 and 58, respectively. The tread 14 also includes several central ribs, designated here by reference numbers 62, 64, and 66, respectively, as the first, second, and third central ribs. Each central rib 62, 64, and 66 is axially positioned between two of the adjacent circumferential cuts 52–58 and is axially separated by two adjacent circumferential cuts 52–58. The tread 14 also includes the first and second lateral ribs 68 and 70. Although not visible in Figure 1, each central rib 62, 64, 66 and each transverse rib 68, 70 includes transverse cuts made in each central rib 62, 64, 66 and each transverse rib 68, 70. The tires according to the second, third, fourth, fifth, and sixth embodiments of the present invention are now described with reference to Figures 2 to 6, respectively, in which components similar to those shown in the preceding figures are shown with the same reference numerals.

[0056] Unlike the tire according to the first embodiment, the tire 10 according to the second embodiment in Figure 2 is configured such that the carcass layers 36 fixed to each bead 32 wrap around the circumferential reinforcing element 35 of each bead 32, in this case the bead wire, with the axially inward portions 3611 and 3621 of the carcass layers 36 fixed to each bead 32 axially positioned toward the inside of the axially outward portions 3612 and 3622 of the carcass layers 36 fixed to each bead 32, and the axle ends 361 and 362 that divide the carcass layers 36 fixed to each bead 32 axially are arranged radially toward the outside of the circumferential reinforcing element 35. The axle ends 361 and 362 of the carcass layers 36 fixed to each bead 32 are arranged radially toward the inside of the tire's equator E. More precisely, each axial end 361, 362 of the carcass layer 36 fixed to each bead 32 is positioned within a radial distance RNC of 30 mm from the radial inner end 351 of each circumferential reinforcing element 33 of each bead 32. In this case, RNC = 23 mm. Unlike the tire according to the second embodiment, the tire 10 according to the third embodiment in Figure 3 is configured such that each axle end 361, 362 of the carcass layer 36 is radially positioned toward the outside of the equator E. In this case, it is highly desirable that each axle end 361, 362 of the carcass layer 36 be axially positioned toward the inside of each axle end 161, 162 of the hoop layer 28.

[0057] Unlike the tire according to the preceding embodiment, the carcass reinforcement 34 of the tire 10 according to the fourth embodiment of Figure 4 includes first and second carcass layers 36, 37 fixed to each bead 32 and extending radially within each sidewall 30, axially within the crown 12, and radially toward the interior of the crown reinforcement 16. The second carcass layer 37 is axially positioned toward the outside of the first carcass layer 36 within each sidewall and radially positioned toward the outside of the first carcass layer 37 within the crown 12. The second carcass layer 37 is axially separated by two axle ends 371 and 372. The second carcass layer 37 includes filamentous carcass reinforcing elements that extend axially from one axle end 371 or 372 to the other along the circumferential direction X of the tire 10 and the principal direction D4, which forms an angle AC, in this case AC = +90°, with an absolute value of 60° or more, preferably 80° to 90°. Unlike the tire according to the fourth embodiment, the tire 10 according to the fifth embodiment in Figure 5 has the first carcass layer 36 arranged as in the second embodiment shown in Figure 2. Furthermore, each axle end 371, 372 of the second carcass layer 37 is axially positioned between the axially inward portions 3611, 3621 and the axially outward portions 3612, 3622 of the first carcass layer 36. The second carcass layer 37 is radially positioned within the crown 12 toward the outside of the first carcass layer 36.

[0058] As previously described in the general description of this application, other alternative arrangements of the second carcass layer 37 are possible. Unlike the first and second embodiments, the tire 10 according to the sixth embodiment of Figure 6 includes two sidewall reinforcement layers 42, 43 that extend radially within at least each sidewall 30 and have radially inner ends 421, 431 positioned radially toward the inside of the equator E, and radially outer ends 422, 432 positioned radially toward the outside of the equator E. Thus, the tire 10 includes two sidewall reinforcement layers 42, 43 that are discontinuous below the crown 12. Official Exam To confirm the properties of elastomer compositions that can be used within the scope of the present invention, 11 elastomer compositions (reference elastomer composition T1 and elastomer compositions C1 to C10) were used. The formulations of each elastomer composition are shown in Table 1, and the amounts of each component are expressed in phr. Each elastomer composition was produced as follows: various other components, excluding reinforcing fillers, elastomer matrices, ozone-proof wax, rubber powder (if present), plasticizers, and vulcanizing agents, were continuously introduced into an internal mixer with an initial tank temperature of 60°C; the "Bandury" type internal mixer was filled to approximately 70% by volume. Subsequently, thermomechanical processing (non-productive stage) was carried out in a single step, continuing for 3-4 minutes until a maximum "decrease" temperature of 165°C was reached. The resulting mixture was collected and cooled, and then the vulcanizing agent (sulfur) and a crosslinking vulcanization accelerator (N-cyclohexyl-2-benzothiazole sulfenamide) were added to an external mixer (homofinisher) at a temperature of 30°C, and everything was mixed for more than 5 minutes but less than 12 minutes (productive stage). To measure these tear strength properties, the elastomer compositions thus obtained were calendered in sheet form.

[0059] Tear test The tear strength is measured using the following method: The force required to break (FRD, in MPa (N / mm)) is determined at 100°C, and the strain at break (DRD, in %) is measured at 100°C. To do this, a test specimen measuring 10 × 145 × 2.5 mm is used, with three cuts exceeding 3 mm in depth made in the center of its length, and the specimen is allowed to break. This allows for the determination of the energy that causes the specimen to break (breaking energy), which is the product of FRD and DRD. To break the specimen, the force required to break and the strain at break are measured for a specimen stretched at 375 mm / min. The results (tear resistance) are expressed using 100 as the baseline; that is, a value of 100 is assigned to the baseline tear energy (T1), and the values ​​for the elastomer compositions are shown in Table 1. The higher the value, the less likely the material is to tear; in other words, the higher the tear resistance.

[0060] [Table 1]

[0061] (1) Isoprene elastomer: natural rubber; (2) Butadiene elastomer: cis-1,4-polybutadiene synthesized using a neodymium catalyst with a cis-1,4 bond content of at least 98 mol%; (3) Carbon black of grade ASTM N550 according to ASTM D1765-14, with an STSA of 39 m² / g as measured according to ASTM D6556-10 and a COAN index of 85 ml / 100 g as measured according to ASTM D3493-16; (4) Total mass of rubber powder particles and unmodified rubber powder, according to ASTM (5)- Rubber powder solid sold by Lehigh Technologies, obtained by recycling (partial reduction of tires), measured in accordance with D5644-01:2013, where the proportion of fine powder particles held on a 250 μm sieve is less than 1% by mass and the proportion of powder particles held on a 177 μm sieve is less than 10% by mass; (6)- Ozone-preventing wax sold by Sasol under the trade name "Vazazon 4959"; (7)- TDAE oil sold by H&R under the trade name "VivaTec 500"; (8)- A mixture of two antioxidants: (N-(1,3-dimethylbutyl)-N-phenyl-p-phenylenediamine sold by Flexsys under the trade name "Santoflex 6-PPD" and 2,2,4-trimethyl-1,2-dihydroquinolone sold by Lanxess); (9)- Pristerene (4931) Stearic acid sold by Unikema; ​​(9) Zinc oxide sold by Umicore: professional grade; (10) N-dicyclohexyl-2-benzothiazole sulfenamide sold by Flexsys under the product name "Santocure CBS".

[0062] In Table 1 above, the mass ratio A / C is the ratio of the content of reinforcing filler expressed in phr to the content of plasticizer expressed in phr, the total A+B is the sum of the content of reinforcing filler expressed in phr and the content of rubber powder expressed in phr, and the mass ratio B / A is the ratio of the content of rubber powder expressed in phr to the content of reinforcing filler expressed in phr. The results in Table 1 show that the elastomer composition according to the present invention exhibits improved tear resistance compared to the control elastomer composition T1 and to elastomer compositions not according to the present invention. In high-load capacity tires with sidewalls that can bend significantly, this performance helps reduce the risk of tearing. The present invention is not limited to the embodiments described above.

Claims

1. A tire (10) for a passenger vehicle, comprising a crown (12), two beads (32), and two sidewalls (30) connecting each bead (32) to the crown (12), wherein the tire is of the high-load capacity type as defined in the 2021 ETRTO Standards Manual, and at least one of the two sidewalls (30) comprises an elastomer composition based on at least one elastomer matrix, at least one reinforcing filler, and at least one rubber powder, the sum of the reinforcing filler content and rubber powder content is in the range of 46 to 62 phr, and the mass ratio of the rubber powder content expressed in phr to the reinforcing filler content expressed in phr is in the range of 0.20 to 1.

50.

2. The tire (10) according to claim 1, wherein the elastomer composition contains a plasticizer, and the mass ratio of the content of the reinforcing filler represented by phr to the content of the plasticizer represented by phr is 4.50 or less, preferably 4.00 or less, and more preferably 3.75 or less.

3. The tire (10) according to claim 1 or 2, wherein the elastomer composition contains a plasticizer, and the mass ratio of the content of the reinforcing filler represented by phr to the content of the plasticizer represented by phr is 1.00 or more, preferably 2.00 or more, and more preferably 2.42 or more.

4. The tire (10) according to any one of claims 1 to 3, wherein the mass ratio of the content of rubber powder represented by phr to the content of reinforcing filler represented by phr is in the range of 0.25 to 1.50, preferably 0.25 to 1.30, more preferably 0.25 to 1.10, and even more preferably 0.28 to 1.

03.

5. The tire (10) according to any one of claims 1 to 4, wherein the reinforcing filler content is in the range of 5 to 70 phr, preferably 5 to 60 phr, more preferably 5 to 55 phr, even more preferably between 5 and 55 phr, very preferably between 10 and 50 phr, and most preferably between 20 and 45 phr.

6. The tire (10) according to any one of claims 1 to 5, wherein the elastomer composition contains a plasticizer, and the plasticizer content is in the range of 2 to 28 phr, more preferably 7 to 24 phr, and even more preferably 10 to 20 phr.

7. A tire (10) according to any one of claims 1 to 6, wherein the rubber powder content is in the range of 2 to 35 phr, more preferably between 5 and 33 phr, more preferably between 6 and 32 phr, more preferably between 7 and 31 phr, and even more preferably between 8 and 30 phr.

8. The tire (10) according to any one of claims 1 to 7, wherein the reinforcing filler mainly comprises carbon black.

9. The tire (10) according to any one of claims 1 to 8, wherein the elastomer matrix comprises at least one isoprene elastomer and at least one butadiene elastomer.

10. The tire (10) according to any one of claims 1 to 9, wherein the elastomer matrix contains at least one butadiene elastomer in a content of 20 to 80 phr, preferably 30 to 70 phr, more preferably between 30 and 70 phr, and even more preferably between 35 and 65 phr.

11. The tire (10) according to any one of claims 1 to 10, wherein the elastomer matrix contains at least one isoprene elastomer in a content within the range of 20 to 80 phr, preferably 30 to 70 phr, more preferably between 30 and 70 phr, and even more preferably between 35 and 65 phr.

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