Cross-linkable elastomeric composition and tire

Abstract

This invention relates to: a cross-linkable elastomeric composition comprising an unsaturated heterocyclic compound; a process for preparing an elastomeric compound; a tire component comprising the aforementioned elastomeric compound; and a tire for vehicle wheels comprising at least the aforementioned tire component.

Description

[0001] TITLE

[0002] “Cross-linkable elastomeric composition and tire:

[0003] TECHNICAL FIELD OF THE INVENTION

[0004] The present invention relates to unsaturated heterocyclic compounds, used as components for the production of cross-linkable elastomeric compositions.

[0005] STATE OF THE ART

[0006] The peculiar characteristic of elastomeric composites is entropic elasticity, which occurs above the glass transition temperature (Tg) of elastomers and underlies their performance. Diene elastomers, i.e., elastomers with unsaturation in the main chain, such as poly(1 ,4-cis-butadiene) and poly(1 ,4-cis-isoprene), are characterized by high main chain mobility, due to the easy rotation of the polymer chain around single bonds near the unsaturations. With the cross-linking of the polymer chains of these unsaturated elastomers, the composite acquires the property of entropic elasticity. However, despite their exceptional elasticity, elastomeric composites as such do not have the mechanical properties required for demanding applications, such as in tire compounds. To achieve such properties, the composites must be loaded with reinforcing fillers.

[0007] Since the early twentieth century, carbon black has been used as a reinforcing filler for elastomeric composites. Thanks to the addition of carbon black, the static and dynamic mechanical properties of elastomeric composites improve. However, carbon black also causes a significant increase in hysteresis and, therefore, energy dissipation in elastomeric composites. It is known that the elastic modulus of a composite material loaded with carbon black, when subjected to sinusoidal stresses, decreases, going from a minimum deformation up to about 25% deformation. This phenomenon is known as the "Payne effect" and is an indicator of the material's energy dissipation.

[0008] To achieve mechanical reinforcement and low energy dissipation, silica is commonly used as a reinforcing filler, replacing or together with carbon black. However, the difference in polarity between silica fillers and rubber polymers leads to considerable difficulties in the mixing process, such as high Mooney viscosities induced by poor dispersion, resulting in worsened processability and shortened shelf life of the composites.

[0009] By using a coupling agent, typically a silane containing sulfur atoms, a chemical bond is established between silica and the elastomer chains; this results in reduced hysteresis and energy dissipation. Indeed, through the chemical reaction between silica and silane, generally referred to as silanization, the polarity of silica is significantly reduced, thus ensuring improved processability and filler dispersion.

[0010] The use of silica has drastically increased in recent decades, despite the abovedescribed disadvantages associated with its use. These disadvantages essentially derive from the surface activity of silica, due to the presence of polar groups capable of promoting extensive supramolecular interactions.

[0011] Moreover, it has been said that the use of silica, as such, entails disadvantages in terms of compound processability, which may require longer mixing cycles, an increase in mixing steps, and may have a significant impact on the curing behavior of the compound.

[0012] A specific problem related to this last disadvantage is the so-called "marching modulus," a phenomenon often observed in the vulcanization of tread compounds S- SBR / BR loaded with silica. In particular, such compounds often show characteristic vulcanization profiles that do not present a distinct maximum in the vulcanization curve, nor a plateau profile within an acceptable time scale, making it difficult to determine the correct curing time of the compound.

[0013] Furthermore, not only is it difficult to determine the optimal vulcanization time, but the physical properties of the rubber compound may vary. It is known that the vulcanization behavior of silica-based rubber compounds is related to several factors, including the degree of dispersion of the reinforcing filler, silanization and the filler- polymer coupling reaction, as well as the donation of free sulfur by the silane coupling agent.

[0014] Another crucial problem is that the reaction between an elastomeric composition, for example a tire compound, under normal operating conditions, with oxygen and ozone, leads to modification of the chemical structure of the polymer chains. The reaction with oxygen introduces oxygenated functional groups into the polymer chain, which negatively affect the properties of elastomers. The reaction with ozone is particularly harmful as it leads to chain scission.

[0015] Paraphenylenediamines are organic compounds containing primary, secondary, or tertiary amine groups and are typically used as antioxidant and antiozonant agents. The most used paraphenylenediamine in tire compounds is N-(1 ,3- dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), a substance that is raising some environmental concerns.

[0016] W02020222103A1 relates to adducts between sp2-hybridized carbon allotropes and linear and / or cyclic dicarboxylic acids derivatives, as components for the production of cross-linkable elastomeric compositions.

[0017] WO2024127265A1 relates to an improved process for preparing an elastomeric composition comprising a linear or cyclic dicarboxylic acid, or a derivative thereof. The use of such compounds has found application in carbon black-based compounds, possibly mixed with silica, but not in compounds based solely on silica as a reinforcing filler, which may encounter the marching modulus problems described above.

[0018] Furthermore, the linear or cyclic dicarboxylic acids described in W02020222103A1 and WO2024127265A1 are sometimes scarcely commercially available and relatively expensive.

[0019] SUMMARY OF THE INVENTION

[0020] The Applicant has addressed the need to develop elastomeric compositions that overcome, at least in part, the disadvantages of the prior art.

[0021] In particular, the Applicant has addressed the problem of providing elastomeric compositions that exhibit a vulcanization profile characterized by slow kinetics in the initial steps (Ts2 and T30), indicative of good processability of the compounds, and fast kinetics at longer times (T90, T95, and T100), with a plateau profile achievable within an acceptable time scale, especially in silica-based compounds, thus mitigating the problem of the "marching modulus."

[0022] Furthermore, the Applicant has addressed the problem of providing elastomeric compositions effectively protected from reaction with oxygen and ozone, with a reduced content of potentially toxic chemicals.

[0023] The Applicant has also addressed the problem of obtaining such elastomeric compositions by simple processes, with reduced environmental impact, using standard solid-state mixing techniques commonly employed in the tire industry.

[0024] The Applicant has found that such results can be achieved by adding particular unsaturated heterocyclic compounds, preferably by a simplified process that involves adding such compounds directly into the elastomeric composition.

[0025] Moreover, the Applicant has found that these unsaturated heterocyclic compounds are a valid alternative to the dicarboxylic acids used in the compound in the process described in WO2024127265A1 or to diacids, sometimes being, at the same time, more easily available on the market and at decidedly lower costs.

[0026] In particular, the Applicant has found that elastomeric compositions comprising these unsaturated heterocyclic compounds exhibit improved vulcanization kinetics, with a substantial reduction of the "marching modulus" problem, which is present in analogous silica-based compositions in the absence of said heterocyclic compounds. Furthermore, the Applicant has also found that such unsaturated heterocyclic compounds, used in elastomeric compositions, can provide antioxidant and antiozonant properties, thus replacing more toxic chemical compounds typically used as antioxidants and antiozonants, such as paraphenylenediamines and, in particular, 6PPD.

[0027] According to a first aspect, the invention relates to a cross-linkable elastomeric composition comprising: a) one or more elastomeric polymers; b) a compound of formula wherein

[0028] X1is selected from the group consisting of: hydrogen, 0, N-R5, or S, wherein, if X1is hydrogen, R1is absent;

[0029] Y is selected from the group consisting of: N-R6, 0, or S;

[0030] Z is 0 or S; and wherein

[0031] R1, R5and R6are independently selected from the group consisting of: hydrogen, C1-C20 acyl, linear or branched C1-C20 alkyl, linear or branched Ci- 020 hydroxyalkyl, linear or branched C2-C6 alkenyl or alkynyl, aryl, linear or branched Ci-Ce alkyl-aryl, linear or branched C2-C6 alkenyl-aryl, linear or branched C2-C6 alkynyl-aryl, and heteroaryl; and

[0032] R2, R3and R4are independently selected from the group consisting of: hydrogen, hydroxyl, C1-C20 ester, linear or branched C1-C20 alkoxyl, linear or branched C1-C6 alkyl, linear or branched C1-C6 hydroxyalkyl, linear or branched C2-C6 alkenyl or alkynyl, aryl, linear or branched C1-C6 alkyl-aryl, linear or branched C2-C6 alkenyl-aryl, linear or branched C2-C6 alkynyl-aryl, and heteroaryl; c) at least one reinforcing filler; and d) a cross-linking system.

[0033] According to a second aspect, the invention relates to a process for preparing an elastomeric compound according to the present invention. This process comprises the following steps: i) providing one or more elastomeric polymers, a compound of formula (I), at least one reinforcing filler, a cross-linking system, and optionally one or more additives; and ii) carrying out at least one mixing step.

[0034] According to a third aspect, the invention relates to a tire component comprising the elastomeric compound according to the present invention.

[0035] According to a fourth aspect, the invention relates to a tire for vehicle wheels comprising at least the above-mentioned tire component.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The description is illustrated here with reference to the attached drawings, which are provided solely by way of example and do not limit the invention.

[0038] Figure 1 schematically shows a semi-sectional view of a tire for vehicle wheels according to the present invention.

[0039] Figure 2 shows the graph of S’ (torque, dNm) as a function of time (s), in which the vulcanization kinetics curves of the formulations of Example 4 (dotted line) and Comparative Example 3 (solid line) are reported.

[0040] DETAILED DESCRIPTION OF THE INVENTION

[0041] Definitions

[0042] In the context of this description and the following claims, the term “phr” (“parts per hundred of rubber”) indicates parts by weight of a particular component per 100 parts by weight of the dry elastomeric polymer.

[0043] Note that, unless otherwise indicated, all percentages are expressed as weight percentages. The term “elastomeric composition” refers to a composition comprising at least one elastomeric polymer and one or more additives, which, when mixed, provides an elastomeric compound suitable for use in tire components.

[0044] Generally, the components of the elastomeric composition are not all introduced into the mixer at the same time but are added sequentially. In particular, the components of the cross-linking system, such as cross-linking agents and, optionally, cross-linking accelerators and / or cross-linking retarders, are usually added in a substep of mixing, after the incorporation and processing of all other components.

[0045] The term “cross-linkable elastomeric composition” refers to an elastomeric composition that comprises at least one elastomeric polymer, a reinforcing filler, and a cross-linking system (or bundle).

[0046] “Cross-linked elastomeric composition (or compound)” means the material obtainable by cross-linking an elastomeric compound.

[0047] By “elastomeric polymer” is meant a natural or synthetic polymer which, after cross-linking, can be repeatedly stretched at room temperature to at least twice its original length and, after removal of the tensile load, returns substantially immediately and forcefully to its approximate original length (as defined in ASTM D1566-11 Standard Terminology Relating to Rubber).

[0048] The term “vulcanization” refers to the cross-linking reaction in a natural or synthetic rubber induced by a sulfur-based vulcanizing agent.

[0049] The term “green” refers to a material, compound, component, or tire that has not yet been vulcanized.

[0050] The term “cross-linking accelerator” refers to a chemical agent capable of decreasing the duration of the cross-linking process and / or the operating temperature. Among the accelerators commonly used for such purposes are, for example, TBBS, sulfonamides, thiazoles, dithiophosphates, dithiocarbamates, guanidines, and sulfur donors, such as, for example, thiurams.

[0051] The term “cross-linking activator” refers to a chemical agent that can further facilitate cross-linking, causing it to occur in a shorter time and, optionally, at lower temperatures. An example of an activator typically used for such purposes is the stearic acid-zinc oxide system.

[0052] The term “cross-linking retarder” refers to a chemical agent capable of delaying the onset of the cross-linking reaction and / or suppressing undesirable side reactions. Among the commonly used retarders is, for example, N-(cyclohexylthio)phthalimide (CTP).

[0053] The term “cross-linking system (or bundle)” refers to a system of chemical agents that comprises at least one cross-linking agent, and optionally, at least one cross-linking accelerator, at least one cross-linking retarder, and / or at least one crosslinking activator.

[0054] The term “reinforcing filler” refers to a reinforcing material typically used industrially to improve the mechanical properties of tires. Among the reinforcing fillers commonly used for such purposes are, for example, carbon black or other sp2- hybridized carbon allotropes such as graphite, graphene, or carbon nanotubes, conventional silica, in particular silica precipitated with strong acids, preferably in amorphous form, diatomaceous earth, calcium carbonate, titanium dioxide, talc, alumina, aluminosilicates, kaolin, silicate fibers, and mixtures thereof.

[0055] The term “white filler” refers to a reinforcing material conventionally used in the industry, selected from conventional silica and silicates, such as sepiolite, palygorskite, also known as attapulgite, montmorillonite, halloysite, and the like, possibly modified by acid treatment and / or derivatization. Note that, in general, white fillers have hydroxyl groups on their surface.

[0056] The term “first mixing step” (or “mixing step 1”) refers to the step of the process for preparing the elastomeric compound in which one or more additives can be incorporated by mixing and, optionally, heating, under specific pressure and temperature conditions, with the exception of the cross-linking agent, which is added in the second mixing step. The first mixing step is also called the “non-productive step.” In the preparation of a compound, there may be several “non-productive” mixing substeps, which may be referred to as 1 a, 1 b, 1 c, 1 d, etc.

[0057] The term “second mixing step” (or “mixing step 2”) refers to the step following mixing step 1 in the process of preparing the elastomeric compound, in which the cross-linking agent and, optionally, further additives and / or ingredients of the crosslinking system are introduced into the elastomeric composition obtained from mixing step 1 and mixed at a controlled temperature, generally at a temperature below 120 °C, so as to provide the cross-linkable elastomeric compound. The second mixing step is also referred to as the “productive step.”

[0058] Note that each mixing step may include several intermediate steps or sub-steps of processing, characterized by the temporary interruption of mixing to allow the addition of one or more ingredients, but without intermediate unloading of the compound.

[0059] According to this description, the expressions “carbon allotrope” and “carbonbased filler” are used interchangeably and / or are both indicated by the abbreviation CA.

[0060] For the purposes of this description and the following claims, the compounds of formula (I) disclosed herein also include derivatives, such as esters, salts, enantiomers, diastereoisomers, preferably esters and salts.

[0061] Detailed description

[0062] According to a first aspect, the invention relates to a cross-linkable elastomeric composition comprising: a) one or more elastomeric polymers; b) a compound of formula wherein

[0063] X1is selected from the group consisting of: hydrogen, 0, N-R5, or S, wherein, if X1is hydrogen, R1is absent;

[0064] Y is selected from the group consisting of: N-R6, 0, or S;

[0065] Z is 0 or S; and wherein

[0066] R1, R5and R6are independently selected from the group consisting of: hydrogen, C1-C20 acyl, linear or branched C1-C20 alkyl, linear or branched Ci- 020 hydroxyalkyl, linear or branched C2-C6 alkenyl or alkynyl, aryl, linear or branched Ci-Ce alkyl-aryl, linear or branched C2-C6 alkenyl-aryl, linear or branched C2-C6 alkynyl-aryl, and heteroaryl; and

[0067] R2, R3and R4are independently selected from the group consisting of: hydrogen, hydroxyl, C1-C20 ester, linear or branched C1-C20 alkoxyl, linear or branched Ci-Ce alkyl, linear or branched Ci-Ce hydroxyalkyl, linear or branched C2-C6 alkenyl or alkynyl, aryl, linear or branched C-i-Ce alkyl-aryl, linear or branched C2-C6 alkenyl-aryl, linear or branched C2-C6 alkynyl-aryl, and heteroaryl; c) at least one reinforcing filler; and d) a cross-linking system.

[0068] Please note that the number of carbon atoms (e.g., C2-C6), as expressed for linear or substituted alkyl-aryl, alkenyl-aryl, and alkynyl-aryl substituents, refers exclusively to the carbons of the alkyl, alkenyl, and alkynyl portions, respectively, and therefore excludes any reference to the number of carbon atoms in the aryl portion.

[0069] Preferably, said X1is 0.

[0070] Preferably, said Y is 0.

[0071] Preferably, said Z is 0.

[0072] According to a preferred embodiment, R1, R5and R6are independently selected from the group consisting of: hydrogen, C1-C6 acyl, linear or branched C1-C6 alkyl, linear or branched C1-C6 hydroxyalkyl, linear or branched C2-C6 alkenyl or alkynyl, aryl, linear or branched C1-C6 alkyl-aryl, linear or branched C2-C6 alkenyl-aryl, linear or branched C2-C6 alkynyl-aryl, and heteroaryl; and

[0073] R2, R3and R4are independently selected from the group consisting of: hydrogen, hydroxyl, linear or branched C1-C6 alkoxyl, linear or branched C1-C6 alkyl, linear or branched C1-C6 hydroxyalkyl, linear or branched C2-C6 alkenyl or alkynyl, aryl, linear or branched C1-C6 alkyl-aryl, linear or branched C2-C6 alkenyl-aryl, linear or branched C2-C6 alkynyl-aryl, and heteroaryl.

[0074] Preferably, said R2and R3are independently selected from the group consisting of: hydrogen, hydroxyl, linear or branched C1-C6 alkyl, linear or branched C1-C6 hydroxyalkyl, more preferably hydroxymethyl; and R4is hydrogen.

[0075] Preferably, R2is selected from linear or branched C1-C6 alkyl, R3is selected from hydrogen, linear or branched C1-C6 alkyl, preferably methyl or ethyl, and R4is hydrogen. More preferably, R2is selected from methyl and ethyl. More preferably, R3is hydrogen.

[0076] Preferably, the compound of formula (I) is represented by at least one of the following formulas:

[0077]

[0078] In particularly preferred embodiments, the compound of formula (I) is selected from the group consisting of: maltol, having the structure of formula (II); ethyl maltol, having the structure of formula (III); and their mixtures. It should be noted that, advantageously, maltol and ethyl maltol are well-known compounds commonly used in the food industry, which exhibit high biocompatibility as well as substantial nontoxicity. Furthermore, these compounds are also easily commercially available, given their widespread use in the food industry, at relatively low cost. Alternatively, said compound of formula (I) is represented by the following formula (XI): wherein

[0079] R7is linear or branched C1-C19 alkyl, preferably linear C4-C17 alkyl, or linear or branched C2-C19 alkenyl, preferably linear C15-C19 alkenyl. More preferably, R7is the alkyl residue of a saturated fatty acid, such as, for example, lauric acid, myristic acid, palmitic acid, stearic acid, or the alkenyl residue of an unsaturated fatty acid, such as, for example, oleic acid or linoleic acid. Even more preferably, said R7is the alkyl residue of oleic acid.

[0080] According to a preferred embodiment, the compound of formula (I) is contained in the cross-linkable elastomeric composition in an amount of at least 0.1 phr, more preferably at least 0.15 phr, and even more preferably at least 1 phr.

[0081] Preferably, the compound of formula (I) is contained in the cross-linkable elastomeric composition in an amount of at most 8 phr, more preferably at most 6 phr, even more preferably at most 4 phr.

[0082] Preferably, the at least one of said one or more elastomeric polymers is an unsaturated elastomeric polymer, selected from the group consisting of: cis-1 ,4- polyisoprene, natural and / or synthetic, 3,4-polyisoprene, polybutadiene, preferably polybutadiene with a high content of 1 ,4-cis units or polybutadiene with a high content of 1 ,2-butadiene monomeric units, isoprene / isobutene copolymers, preferably halogenated isoprene / isobutene copolymers, preferably butyl rubber, more preferably halogenated butyl rubber, even more preferably chlorobutyl rubber or bromobutyl rubber, styrene / 1 ,3-butadiene copolymers, styrene / isoprene / 1 ,3-butadiene copolymers, partially hydrogenated styrene-1 ,3-butadiene, and mixtures thereof.

[0083] By partially hydrogenated styrene-1 , 3-butadiene is meant styrene-1 ,3- butadiene having a degree of hydrogenation of the conjugated diene units between 60 and 99 mol%.

[0084] By polybutadiene with a high content of 1 ,4-cis monomeric units is meant polybutadiene having a content of 1 ,4-cis monomeric units of at least 95%.

[0085] By polybutadiene with a high content of 1 ,2-butadiene monomeric units is meant polybutadiene having a content of 1 ,2-butadiene monomeric units of at least 10%. According to a particularly preferred embodiment, the one or more elastomeric polymers is selected from the group consisting of: cis-1 ,4-polyisoprene, natural (natural rubber or NR) and / or synthetic, 1 ,4-polybutadiene (BR), styrene-butadiene copolymer (SBR), and mixtures thereof.

[0086] In this context, styrene-butadiene copolymer (SBR) means a copolymer comprising styrene and butadiene monomer units, with a styrene content preferably between 10 and 42% by weight and a vinyl content between 10 and 70% by weight, relative to the butadiene.

[0087] Preferably, the styrene-butadiene copolymer has a Tg comprised between -70 and -10 °C, more preferably between -65 and -25 °C, and preferably contains from 10 to 30% by weight of styrene and from 25 to 67% by weight of vinyl.

[0088] The styrene-butadiene copolymer may contain, in addition to styrene and butadiene units, a small amount, for example equal to or less than 5% by weight, of additional monomer units such as isoprene, dimethylbutadiene, pentadiene, methylstyrene, ethylstyrene, divinylbenzene, and diisopropenylbenzene.

[0089] Preferably, the styrene-butadiene copolymer is a random polymer.

[0090] In a particularly preferred embodiment, the styrene-butadiene copolymer is prepared by solution polymerization (S-SBR).

[0091] Solution synthesis generally yields polymers with a narrower molecular weight distribution, fewer chain branches, higher molecular weight, and greater control over the mode of butadiene insertion, compared to analogous polymers obtainable by emulsion polymerization.

[0092] The styrene-butadiene copolymer can also be prepared by emulsion polymerization (E-SBR).

[0093] Preferably, the styrene-butadiene copolymer is a random and coupled polymer.

[0094] Note that the unsaturated elastomeric polymer can be an unsaturated elastomer based on diene or non-diene monomers, functionalized by reaction with suitable functionalizing groups, such as chain terminators and / or coupling agents. This reaction can be promoted by an organometallic initiator, such as, for example, an alkyllithium.

[0095] Preferably, the styrene-butadiene copolymer is a functionalized SBR copolymer.

[0096] Preferably, said functional groups are selected from the group consisting of: alkoxysilanes, mercaptosilanes, sulfur-containing groups, amine groups, amide groups, epoxides, hydroxides, and their combinations. The alkoxysilane groups suitable for the purposes of the present invention include monoalkoxy, dialkoxy, and trialkoxy silanes. The sulfur-containing groups suitable for the purposes of the present invention are selected from the group consisting of: thiol, thioether, thioglycol, thioester, sulfide, or sulfanilic group. The suitable amine functional groups for the purposes of the present invention are selected from primary, secondary, and tertiary amine groups.

[0097] In a further preferred embodiment, the styrene-butadiene copolymer is a random, coupled, and functionalized copolymer.

[0098] The diene elastomeric polymers are preferably solid.

[0099] Among the SBR copolymers suitable for the purposes of the present invention are, for example, SPRINTAN™ SLR 4630, SPRINTAN™ SLR 4602, and SPRINTAN™ SLR 3402 by Trinseo.

[0100] Among the natural cis-1 ,4-polyisoprene (NR) polymers suitable for the purposes of the present invention are, for example, solid natural rubber SIR20 by Eatern GR Thailand - Chonburi, solid natural rubber STR20 by Von Bundit, natural rubber of the SMR20 type by LEE RUBBER CO. PTE LTD, KUALA KRAI, and GEB type by Hevea- TEC.

[0101] Examples of poly(1 ,4-cis-butadiene) (BR) suitable for the purposes of the present invention include Europrene Neocis® by Polimeri Europa, SKD NHEODIMIO NIZHN by PAO Nizhnekamskneftekhim, HIGH CIS POLYBUTADIENE (NICKEL TYPE) by Trinseo, and Europrene Neocis BR40 (S-0129) by Versalis.

[0102] In a first preferred embodiment, the at least one elastomeric polymer is a mixture of cis-1 ,4-polyisoprene, preferably natural (NR), S-SBR, and 1 ,4-polybutadiene (BR).

[0103] In a second preferred embodiment, the at least one elastomeric polymer is a mixture of 1 ,4-polybutadiene (BR) and S-SBR.

[0104] In a third preferred embodiment, the at least one elastomeric polymer is a mixture of cis-1 ,4-polyisoprene, preferably natural (NR), and 1 ,4-polybutadiene (BR).

[0105] In a fourth preferred embodiment, the at least one elastomeric polymer is cis- 1 ,4-polyisoprene, preferably natural (NR).

[0106] The cross-linkable elastomeric composition may further comprise at least one elastomer of one or more mono-olefins. The mono-olefins may be selected from: ethylene and 1 -olefins having a number of carbon atoms ranging from 3 to 12, such as, for example, propylene, 1 -butene, 1 -pentene, 1 -hexene, 1 -octene, or mixtures thereof.

[0107] The elastomer of one or more mono-olefins may comprise a diene, which generally has from 4 to 20 carbon atoms and is preferably selected from: 1 ,3- butadiene, isoprene, 1 ,4-hexadiene, 1 ,4-cyclohexadiene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, vinylnorbornene, or mixtures of these dienes. The diene may optionally be halogenated. Among these elastomers of one or more mono-olefins, the following are preferred: ethylene / propylene copolymers (EPR), ethylene / propylene / diene copolymers (EPDM), and poly(isobutene).

[0108] Preferably, the at least one reinforcing filler is selected from the group consisting of: sp2-hybridized carbon allotrope, silica, layered silicates, optionally modified magnesium silicates, mixed aluminum and magnesium oxides with a lamellar structure, alumina, aluminum silicates, and mixtures thereof.

[0109] It should be noted that silica may be a modified silica.

[0110] In particular, silica may be modified, for example, by reaction with siloxanes (as described in W02018078480A1 ), with pyrroles (as described in W02016050887A1 ), or with suitable silanizing agents. Commercial examples of silanizing agents suitable for the purposes of the present invention include Si69, Dynasilan AMEO, and Dynasilan GLYEO by Evonik.

[0111] Modified silica may be a sulfur-silanized silica. Sulfur-silanized silica is a silica prepared by reacting a silica or a metal silicate with at least one sulfur-containing silanizing agent. A suitable commercial example of sulfur-silanized silica is Agilon 400 silica by PPG.

[0112] Commercial examples of silica suitable for the purposes of the present invention include Zeosil 1165 MP, Zeosil 1115 MP, Zeosil 185 GR, Efficium by Solvay, Newsil HD90 and Newsil HD200 by Wuxi, K160 and K195 by Wilmar, H160AT and H180 AT by IQE, Zeopol 8755 and 8745 by Huber, Perkasil TF100 by Grace, Hi-Sil EZ 120 G, EZ 160G, EZ 200G by PPG, Ultrasil 7000 GR and Ultrasil 9100 GR by Evonik, and K 160 (rice husk silica) by Wilmar.

[0113] Preferably, said sp2-hybridized carbon allotrope is selected from the group consisting of: carbon black, graphene, bilayer graphene, multilayer graphene (from 3 to 10 layers), graphite, single-wall or multi-wall carbon nanotubes, carbon nanotubes with longitudinal or helical extension, nanocones, nanohorns, nanotoroids, fullerenes, and mixtures thereof.

[0114] Preferably, carbon black is selected from those having a surface area not less than 20 m2 / g, preferably greater than 50 m2 / g (as determined by STSA - statistical thickness surface area according to ISO 18852:2005).

[0115] Examples of carbon black suitable for the purposes of the present invention include: N110, N115, N121 , N134, N220, N234, N326, N330, N375, N550, and N660, marketed by Birla Group (India) or Cabot Corporation; Vulcan® 1391 supplied by Cabot Corporation or by Birla Carbon™ 2115 supplied by Birla Group.

[0116] Preferably, said graphite is high surface area graphite.

[0117] High surface area graphite refers to graphite having a surface area, measured by the BET method, of at least 330 m2 / g.

[0118] Preferably, the at least one reinforcing filler is contained in the cross-linkable elastomeric composition in an amount comprised between 10 and 150 phr.

[0119] In accordance with a first preferred embodiment, the at least one reinforcing filler is silica.

[0120] In accordance with said first preferred embodiment, silica is contained in the cross-linkable elastomeric composition in an amount of at least 30 phr, preferably at least 45 phr.

[0121] According to this first preferred embodiment, silica is contained in the cross- linkable elastomeric composition in an amount of at most 130 phr, preferably at most 80 phr, more preferably at most 75 phr.

[0122] Also according to said first preferred embodiment, carbon black is optionally contained in the cross-linkable elastomeric composition in an amount of at most 10 phr, preferably at most 5 phr.

[0123] In accordance with a second preferred embodiment, the at least one reinforcing filler is a mixture of carbon black and silica.

[0124] In accordance with this second preferred embodiment, silica is contained in the cross-linkable elastomeric composition in an amount of at least 30 phr, preferably at least 45 phr.

[0125] Further according to this second preferred embodiment, silica is present in the cross-linkable elastomeric composition in an amount of at most 100 phr, preferably at most 75 phr, more preferably at most 60 phr.

[0126] Also in accordance with this second preferred embodiment, carbon black is contained in the cross-linkable elastomeric composition in an amount of at least 10 phr, preferably at least 20 phr.

[0127] Also according to this preferred second embodiment, carbon black is contained in the cross-linkable elastomeric composition in an amount of at most 45 phr, preferably at most 35 phr.

[0128] In accordance with a third preferred embodiment, the at least one reinforcing filler is carbon black.

[0129] In accordance with said third preferred embodiment, carbon black is contained in the cross-linkable elastomeric composition in an amount of at least 10 phr, preferably at least 20 phr.

[0130] Also according to said third preferred embodiment, carbon black is contained in the cross-linkable elastomeric composition in an amount of at most 60 phr.

[0131] In accordance with a fourth preferred embodiment, the at least one reinforcing filler is a white filler selected from the group consisting of: silica, layered silicates, optionally modified magnesium silicates, and mixtures thereof, in combination with single-wall or multi-wall carbon nanotubes, and optionally in combination with carbon black.

[0132] In accordance with said fourth preferred embodiment, the at least one white filler is contained in the cross-linkable elastomeric composition in an amount of at least 15 phr, preferably at least 20 phr.

[0133] Also in accordance with said fourth preferred embodiment, the at least one white filler is contained in the cross-linkable elastomeric composition in an amount of at most 130 phr, preferably a most 75 phr, more preferably at most 45 phr, and even more preferably at most 35 phr.

[0134] According to said fourth preferred embodiment, single-wall or multi-wall carbon nanotubes are contained in the cross-linkable elastomeric composition in an amount of at most 5 phr.

[0135] Also in accordance with said fourth preferred embodiment, carbon black is contained in the cross-linkable elastomeric composition in an amount of at most 10 phr, preferably at most 5 phr.

[0136] Preferably, said cross-linkable elastomeric composition comprises one or more additives, said one or more additives being selected from the group consisting of: antiaging agents, plasticizers, adhesives, modifying resins, coupling agents, and mixtures thereof.

[0137] Preferably, said anti-aging agents are selected from the group consisting of:

[0138] • at least one antioxidant,

[0139] • at least one antiozonant, and

[0140] • mixtures thereof.

[0141] Preferably, said anti-aging agents are contained in the cross-linkable elastomeric composition in a total amount of at least 1 phr.

[0142] Still preferably, said anti-aging agents are contained in the cross-linkable elastomeric composition in a total amount of at most 20 phr.

[0143] Preferably, said at least one antioxidant is a quinoline antioxidant, more preferably TMQ, and / or a phenolic antioxidant, more preferably 4,6- bis(octylthiomethyl)-o-cresol. Said at least one antioxidant may be added as such, or may be supported on a reinforcing filler (such as, for example, carbon black or silica), in order to facilitate its incorporation into the elastomeric composition. A phenolic antioxidant particularly suitable for the purposes of the invention is, for example, 4,6- bis(octylthiomethyl)-o-cresol supported at 67% active on amorphous silica.

[0144] Preferably, said at least one antioxidant is contained in the cross-linkable elastomeric composition in an amount of at least 0.1 phr, more preferably at least 0.5 phr, and even more preferably at least 1 phr.

[0145] Still preferably, said at least one antioxidant is contained in the cross-linkable elastomeric composition in an amount of at most 20 phr, more preferably at most 15 phr, and even more preferably at most 10 phr.

[0146] Preferably, said at least one antiozonant is selected from at least one p- phenylenediamine, and / or at least one static protective agent selected from a wax and / or a polymeric static protective agent. Preferably, said at least one antiozonant is contained in the cross-linkable elastomeric composition in an amount of at least 0.1 phr, more preferably at least 0.5 phr, even more preferably at least 1 phr.

[0147] Still more preferably, said at least one antiozonant is contained in the cross- linkable elastomeric composition in an amount of at most 20 phr, more preferably at most 10 phr, even more preferably at most 7 phr.

[0148] The wax may be, for example, a petroleum wax or a mixture of paraffins.

[0149] Among the commercial examples of waxes suitable for the purposes of the present invention are the N-paraffin mixture by Repsol, the microcrystalline wax Antilux® 654 by Rhein Chemie, and Riowax BNO1 by SER S.p.A.

[0150] Preferably, the polymeric static protective agent is selected from the group consisting of polyether, ethylene-propylene rubber, and (meth)acrylic copolymer.

[0151] Preferably, said polyether is polyethylene glycol, more preferably PEG1500.

[0152] Preferably, said (meth)acrylic copolymer is a copolymer of (meth)acrylic acid with ethylenically unsaturated monomers containing polyoxyethylene side chains.

[0153] Still more preferably, said ethylene-propylene rubber is liquid EDPM.

[0154] Among the commercial examples of polymeric static protective agents suitable for the purposes of the present invention are Melflux PP100 F by BASF and Trilene CP1100 by Lion Elastomers.

[0155] The static protective agent may be contained in the cross-linkable elastomeric composition in an amount of at least 1 phr, preferably at least 1 .5 phr.

[0156] The static protective agent may be contained in the cross-linkable elastomeric composition in an amount of at most 20 phr, preferably at most 10 phr, more preferably at most 3 phr.

[0157] Preferably, the wax is contained in the cross-linkable elastomeric composition in an amount of at least 0.1 phr, preferably at least 0.3 phr, more preferably at least 0.5 phr, even more preferably at least 1 phr.

[0158] Preferably, the wax is contained in the cross-linkable elastomeric composition in an amount of at most 4 phr, more preferably at most 3 phr, even more preferably at most 2 phr.

[0159] P-phenylenediamines suitable for the purposes of the present invention are preferably selected from the group consisting of: N-isopropyl-N'-phenyl-p- phenylenediamine (IPPD), N-(1 ,3-dimethyl-butyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-bis-(1 ,4-dimethylpentyl)-p-phenylenediamine (77PD), N, N'-bis-(1 -ethyl- 3-methyl-pentyl)-p-phenylenediamine (DOPD), N,N'-bis-(1 ,4-dimethyl-pentyl)-p- phenylenediamine, N,N'-diphenyl-p-phenylenediamine (DPPD), N, N'-ditolyl-p- phenylenediamine (DTPD), N,N'-di-beta-naphthyl-p-phenylenediamine (DNPD), N,N'- bis(1 -methylethyl)-p-phenylenediamine, N,N'-di-sec-butyl-p-phenylenediamine (44PD), N-phenyl-N-cyclohexyl-p-phenylenediamine, N-phenyl-N'-1 -methylethyl-p- phenylenediamine and the like, and their mixtures, preferably N-(1 ,3-dimethylbutyl)-N'- phenyl-p-phenylenediamine (6PPD). A commercial example of a suitable anti-ozonant for the purposes of the present invention is 6PPD Santoflex™ produced by Flexsys. The at least one p-phenylenediamine may be present in the cross-linkable elastomeric composition in an amount preferably of at least 0.5 phr.

[0160] Preferably, at least one p-phenylenediamine is contained in the cross-linkable elastomeric composition in an amount of at most 3.0 phr.

[0161] Preferably, the cross-linking system comprises:

[0162] - at least one cross-linking agent; and

[0163] - at least one cross-linking activator;

[0164] - at least one cross-linking accelerator; and / or

[0165] - at least one cross-linking retarder.

[0166] Preferably, said cross-linking agent is a vulcanizing agent, preferably selected from sulfur (Ss) and / or sulfur donors.

[0167] Among the commercial examples of vulcanizing agents suitable for the purposes of the present invention are soluble sulfur from Zolfindustria (Italy) or insoluble sulfur (at 67%) from Flexsys Verkauf GmbH.

[0168] Among the particularly preferred sulfur donors are, for example, sulfurated agents such as bis[(trialkoxysilyl)propyl] polysulfides, thiurams, dithiomorpholines, and caprolactam disulfide.

[0169] Preferably, at least one cross-linking agent may be contained in the cross- linkable elastomeric composition in an amount of at least 0.2 phr, more preferably at least 0.5 phr.

[0170] Preferably, at least one cross-linking agent may be comprised in the cross- linkable elastomeric composition in an amount of at most 15 phr, more preferably at most 10 phr.

[0171] Preferably, at least one cross-linking activator is selected from the group consisting of: ZnO, ZnCO3, zinc salts of saturated or unsaturated fatty acids, and mixtures thereof.

[0172] It should be noted that the zinc salts of saturated or unsaturated fatty acids are preferably formed in situ in the cross-linkable elastomeric composition, starting from ZnO and at least one saturated and / or unsaturated fatty acid having from 8 to 18 carbon atoms. Generally, zinc stearate is used, preferably formed in situ from ZnO and stearic acid in the elastomeric composition.

[0173] An example of a commercially available cross-linking activator is Aktiplast ST by Rheinchemie. Preferably, the at least one cross-linking activator is contained in the cross- linkable elastomeric composition in an amount preferably of at least 0.2 phr, more preferably at least 1 phr.

[0174] Preferably, the at least one cross-linking activator is contained in the cross- linkable elastomeric composition in an amount preferably of at most 15 phr, more preferably at most 10 phr.

[0175] Preferably, said at least one cross-linking accelerator is selected from the group consisting of: tetraisobutylthiuram disulfide (TiBTD), N-cyclohexyl-2-benzothiazole sulfenamide (CBS), and TBBS, mercaptobenzothiazole (MBT), mercaptobenzothiazole disulfide (MBTS), and mixtures thereof.

[0176] Commercial examples of cross-linking accelerators suitable for use in the present elastomeric composition are N-cyclohexyl-2-benzothiazole sulfenamide Vulkacit® (CBS or CZ) and N-tert-butyl-2-benzothiazole sulfenamide, Vulkacit® NZ / EGC, marketed by Lanxess.

[0177] Preferably, at least one cross-linking retarder is selected from the group consisting of: urea, phthalic anhydride, N-nitrosodiphenylamine, N- cyclohexylthiophthalimide (CTP or PVI), and mixtures thereof.

[0178] A commercial example of a cross-linking retarder suitable for the purposes of the present invention is N-cyclohexylthiophthalimide VULKALENT G by Lanxess.

[0179] The at least one cross-linking retarder may be present in the present elastomeric composition preferably in an amount ranging from 0.05 phr to 2 phr.

[0180] Preferably, said plasticizers are at least one oil selected from the group consisting of: mineral oils, vegetable oils, synthetic oils, and mixtures thereof.

[0181] The at least one oil may be a petroleum-derived oil selected from paraffins (saturated hydrocarbons), naphthenics, polycyclic aromatics, and mixtures thereof.

[0182] Petroleum-derived oils suitable for the purposes of the present invention are preferably selected from the group consisting of: aromatic oil, paraffinic and / or naphthenic oil, such as, for example, MES (Mild Extract Solvated), DAE (Distillate Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), TRAE (Treated Residual Aromatic Extract), RAE (Residual Aromatic Extract).

[0183] The at least one oil may be a process oil derived from petroleum with a low aromatic content, selected, for example, from TDAE, TRAE, MES, paraffinic or naphthenic oils. Among these, naphthenic oils are the most preferred. Examples of suitable petroleum-derived oils are NYTEX 4700 by Nynas, EXTENSOIL 1471 by Repsol, VIVATEC 500 by H&R.

[0184] Vegetable oils suitable for the purposes of the present invention are preferably selected from the group consisting of: sunflower oil, soybean oil, linseed oil, rapeseed oil, castor oil, and cottonseed oil.

[0185] Examples of suitable commercial vegetable oils are: RADIA 6132 by Oleon, Agripure AP 18 and Agripure AP 75 by Cargill, soybean oil by Wilmar.

[0186] Preferably, the modifying resins comprise at least one resin selected from the group consisting of: hydrocarbon resin, phenolic resin, natural terpene resin, natural rosin resin, and mixtures thereof. More preferably, the at least one resin is a hydrocarbon resin.

[0187] The hydrocarbon resin may comprise at least one aliphatic resin, at least one aromatic resin, at least one resin comprising both aliphatic and aromatic monomers, or combinations thereof.

[0188] The hydrocarbon resin may be natural (for example, of vegetable origin or petroleum-derived) or synthetic. In some cases, without limiting the invention, this type of resin contains essentially only hydrogen and carbon atoms.

[0189] Preferably, the hydrocarbon resin is selected from homo- or copolymers of cyclopentadiene (CPD), dicyclopentadiene (DCPD), homo- or copolymers of terpenes, homo- or copolymers of the C5 fraction, and their mixtures, preferably DCPD / vinylaromatic copolymers, DCPD / terpene copolymers, DCPD / C5 fraction copolymers, terpene / vinylaromatic copolymers, C5 fraction / vinylaromatic copolymers, and their combinations.

[0190] Examples of vinylaromatic monomers are styrene, alpha-methylstyrene, ortho-, meta-, para-methylstyrene, vinyl-toluene, para-tert-butylstyrene, methoxy-styrene, chloro-styrene, vinyl-mesilene, divinyl-benzene, vinyl-naphthalene, vinylaromatic monomers derived from the C8-C10 fraction, in particular C9.

[0191] The hydrocarbon resin is preferably selected from resins based on coumaroneindene, styrene-indene, styrene-alkylstyrene, and aliphatic resins.

[0192] Specific examples of commercial hydrocarbon resins are NOVARES C resins by RUTGERS CHEMICAL GmbH (synthetic resins based on indene-coumarone), preferably NOVARES C10, C30, and C90.

[0193] Examples of commercially available styrene-indene hydrocarbon resins include UNILENE At 100 by Braskem and Novares TL 90 by Rain Carbon.

[0194] Examples of commercially available alkyl-styrene hydrocarbon resins include: Sylvares SA 85 by Arzona Chemical, Kristalex F 85 by Synthomer, Kristalex 5140 by Synthomer.

[0195] Commercially available aliphatic hydrocarbon resins suitable for the purposes of the present invention include, for example: Escorez® 1102 by ExxonMobil, Piccotac 1100 by Eastman, Quintone A 100 by Zeon Chemicals.

[0196] The phenolic resin may be selected from resins based on alkylphenolformaldehyde, alkylphenolic resins modified with rosin, resins based on alkylphenolacetylene, modified alkylphenolic resins, and terpene-phenol-based resins.

[0197] Examples of commercially available phenolic resins that can be used in the present invention are: RESINA SP-1068 (by SI GROUP Inc.) (octylphenolformaldehyde resin); DUREZ 32333 (by Sumitomo Bakelite) (phenol-formaldehyde resin); KORESIN (by BASF Company) (p-t-butylphenol-acetylene resin); SYLVARES TP 115 (by Arizona Chemicals) (terpene-phenolic resin).

[0198] The natural terpene resin may be a polyterpene resin selected from homo- or copolymers of alpha-pinene, beta-pinene, limonene, possibly in mixture with vinylaromatic (styrene) and / or phenolic monomers.

[0199] Examples of commercially available natural terpene resins suitable for the purposes of the present invention are: Piccolyte F90 and Piccolyte F105 by PINOVA, Dercolyte A 115 and Dercolyte M 115 by DRT.

[0200] The term "rosin" commonly refers to mixtures of isomeric organic acids (rosin acids), characterized by a common structure comprising three fused C6 rings, double bonds in varying number and position, and a single carboxyl group, where the main component is abietic acid (C20H30O2) and its dihydroabietic (C20H32O2) and dehydroabietic (C20H28O2) derivatives.

[0201] Examples of commercially available natural rosin resins suitable for the purposes of the present invention include HYDROGRAL G and DERTOLINE P 105, marketed by DRT, or STAYBELITE™ ESTER 3-E by Synthomer.

[0202] Preferably, said at least one coupling agent is a silane coupling agent.

[0203] Preferably, said silane coupling agent is contained in the cross-linkable elastomeric composition in an amount of at least 0.5 phr, more preferably at least 1 phr or 2 phr, and even more preferably at least 2 phr or 3 phr. Preferably, said silane coupling agent is contained in the cross-linkable elastomeric composition in an amount of at most 20.0 phr, more preferably at most 15.0 phr, and even more preferably at most 10.0 phr.

[0204] Preferably, said silane coupling agent is selected from those having at least one hydrolyzable silane group, which can be identified, for example, by the following general formula:

[0205] (R’)3Si-CnH2n-X where the R' groups, identical or different from each other, are selected from: alkyl, alkoxy, or aryloxy groups or halogen atoms, provided that at least one of the R' groups is an alkoxy or aryloxy; n is an integer from 1 to 6; X is a group selected from: nitroso, mercapto, amino, epoxy, vinyl, imide, chloro, -(S)mCnH2n-Si-(R')3, and -S- COR', where m and n are integers from 1 to 6 and the R' groups are as defined above.

[0206] Particularly preferred silane coupling agents are bis(3- triethoxysilylpropyl)tetrasulfide and bis(3-triethoxysilylpropyl)disulfide. These coupling agents can be added as such or in a mixture with an inert filler (such as, for example, carbon black), in order to facilitate their incorporation into the elastomeric composition.

[0207] Examples of silane coupling agents suitable for the purposes of the present invention are TESPT bis(3-triethoxysilylpropyl)tetrasulfide Si69 by Evonik, TESPD bis(3-triethoxysilylpropyl)disulfide Si266 by Evonik, and TESPD (at 50% by weight supported on carbon black) by Jingzhou Jianghan Fine Chemical Co., LTD.

[0208] According to a second aspect, the invention relates to a process for preparing the elastomeric compound according to the present invention, said process comprising the following steps: i) providing one or more elastomeric polymers, a compound of formula (I), at least one reinforcing filler, a cross-linking system, and optionally one or more additives; and ii) carrying out at least one mixing step.

[0209] Preferably, step ii) of carrying out at least one mixing step comprises a first mixing step.

[0210] Typically, this first mixing step is carried out by mixing together the polymeric components with the reinforcing fillers and any other additives present, according to techniques known in the art.

[0211] The first mixing step is preferably conducted at a temperature between 40 °C and 160 °C.

[0212] In general, mixing can be performed, for example, using an open mill mixer and / or an internal mixer with tangential rotors (Banbury®), and / or with intermeshing rotors (Intermix™), and / or in continuous mixers such as Ko-Kneader™, and / or twin- screw or multi-screw mixers, and / or planetary mixers.

[0213] The ingredients are generally not all introduced into the mixer simultaneously but are typically added sequentially.

[0214] The cross-linking agents, including a cross-linking agent and optionally at least one cross-linking activator, at least one cross-linking accelerator, and / or at least one cross-linking retarder, are preferably added in a second mixing step, downstream of the first mixing step.

[0215] The second mixing step is an additional mixing step carried out according to techniques known in the art, preferably using sulfur-based cross-linking systems, which are commonly used for diene elastomeric polymers.

[0216] For this purpose, after one or more steps of thermo-mechanical treatment, a sulfur-based cross-linking agent is incorporated into the materials together with crosslinking accelerators, cross-linking activators, and / or cross-linking retarders.

[0217] In the second mixing step, the temperature is generally kept below 120 °C and preferably below 100 °C, in order to avoid any undesired pre-cross-linking phenomena.

[0218] Therefore, in a preferred embodiment, step ii) of carrying out at least one mixing step comprises a second mixing step.

[0219] The compound of formula (I) can be introduced in the first mixing step, in the second step, or in both the aforementioned first and second mixing steps.

[0220] It should be noted that the compound of formula (I) can be introduced as such or in the form of a preformed adduct with a sp2-hybridized carbon allotrope, preferably high surface area graphite. In the latter case, said adduct is prepared according to any of the preparation methods described in W02020222103A1 , which is incorporated herein by reference, replacing the carboxylic acid derivatives described therein with the compound of formula (I) of the present invention.

[0221] In the elastomeric compound, the individual components of the cross-linkable elastomeric composition do not always remain unchanged or individually traceable, as they may be transformed, wholly or in part, due to interaction with other components or as a result of energy such as heat and / or mechanical energy supplied. According to a third aspect, the invention concerns a tire component comprising the elastomeric compound according to the present invention.

[0222] Said tire component is preferably selected from: tread band, underlayer, antiabrasive strip, sidewall, sidewall insert, mini-sidewall, liner, inner liner, rubber layers, bead filler, bead reinforcement layers (flipper), bead protection layers (chafer), rubberizing compounds for fabrics (polymeric or metallic).

[0223] In a particularly preferred embodiment, the tire component is a tread band.

[0224] According to a fourth aspect, the invention relates a tire for vehicle wheels comprising the at least one tire component comprising the elastomeric compound according to the present invention.

[0225] In one embodiment, the tire for vehicle wheels according to the present invention comprises at least the following components:

[0226] - a carcass structure comprising at least one carcass ply with opposite lateral edges associated with the respective bead structures;

[0227] - a pair of sidewalls applied to the lateral surfaces of the carcass structure, each in an axially outer position;

[0228] - optionally, a belt structure applied in a radially outer position with respect to the carcass structure;

[0229] - a tread band applied in a radially outer position with respect to the carcass structure or, if present, to the belt structure;

[0230] - optionally, a layer of elastomeric material, called an underlayer, applied in a radially inner position with respect to said tread band; where at least one component, preferably the tread band, comprises the crosslinked elastomeric compound obtained by cross-linking the cross-linkable elastomeric compound according to the present invention.

[0231] In a preferred embodiment, the tire according to the present invention can be produced by a process comprising:

[0232] (a) producing a green tire comprising a green tread band applied in a radially outer position of the tire;

[0233] (b) subjecting said green tire to molding and cross-linking in order to obtain a finished tire; in which said green tread band comprises the elastomeric compound of the invention. In one embodiment, the tire according to the invention is a tire for passenger cars, with standard or high performance, or for off-road vehicles, preferably a tire for passenger cars, designed for personal use vehicles such as sedans, coupes, crossovers, SLIVs, minivans, and small pickups.

[0234] In a further embodiment, the tire according to the invention is a tire for motorcycles.

[0235] The tire according to the invention can be a tire for vehicles with two, three, or four wheels.

[0236] In a further embodiment, the tire according to the invention is a tire for bicycle wheels. A tire for bicycle wheels typically comprises a carcass structure turned around a pair of bead cores, at the beads, and a tread band arranged in a radially outer position with respect to the carcass structure.

[0237] An example of a tire for vehicle wheel is illustrated in a radial half-section in Figure 1 .

[0238] In Figure 1 , "a" indicates an axial direction and "X" indicates a radial direction; in particular, X-X indicates the profile of the equatorial plane. For simplicity, Figure 1 shows only a portion of the tire, while the remaining portion not shown is identical and arranged symmetrically with respect to the equatorial planeHX-X".

[0239] In the embodiment shown in Figure 1 , tire 100 for vehicle wheels is a tire 100 for four-wheeled vehicles. The tire 100 for four-wheeled vehicles comprises at least a carcass structure, which includes at least one carcass ply 101 having opposite terminal edges, with respective annular anchoring structures 102, called beads, which may be associated with a bead filler 104.

[0240] The area of the tire comprising bead 102 and bead filler 104 forms a bead structure 103, configured for anchoring the tire to a corresponding mounting rim, not shown in Figure 1 .

[0241] The carcass structure is usually of the radial type, meaning that the reinforcing elements of at least one carcass ply 101 are located on planes that include the axis of rotation of the tire and are substantially perpendicular to the equatorial plane of the tire. These reinforcing elements are generally made of textile cords.

[0242] Each bead structure is associated with the carcass structure by folding the opposite lateral edges of at least one carcass ply 101 around the annular anchoring structure 102, so as to form the so-called carcass turn-ups 101 a, as illustrated in Figure 1.

[0243] In one embodiment, the coupling between the carcass structure and the bead structure can be provided by a second carcass ply (not shown in Figure 1 ), applied in an axially outer position with respect to the first carcass ply.

[0244] An anti-abrasive strip 105, possibly made of elastomeric material, is arranged on the outer side of each bead structure 103.

[0245] The carcass structure is associated with a belt structure 106, comprising one or more belt plies 106a, 106b, arranged in radial superposition with respect to the carcass ply, with reinforcing cords typically made of textile and / or metallic material, embedded in a layer of elastomeric material.

[0246] These reinforcing cords may have a crossed orientation with respect to the circumferential direction of development of the tire 100.

[0247] The term "circumferential direction" refers to a direction generally oriented along the direction of rotation of the tire.

[0248] At least one zero-degree reinforcement ply 106c, commonly known as a "0° belt," can be applied in a radially outer position to the belt plies 106a, 106b, and generally incorporates a plurality of elongated reinforcing elements, typically metallic or textile cords, oriented in a substantially circumferential direction, thus forming an angle of a few degrees (for example, an angle between about 0° and 6°) with respect to a direction parallel to the equatorial plane of the tire, these metallic or textile cords being coated with an elastomeric material.

[0249] A tread band 109 comprising the elastomeric compound according to the invention is applied in a radially outer position to the belt structure 106. In addition, the respective sidewalls 108 made of elastomeric material are applied in an axially outer position on the lateral surfaces of the carcass structure, each of which extends from one of the lateral edges of the tread band 109 to the respective bead structure 103.

[0250] In the radially outer position, the tread band 109 has a rolling surface 109a intended to come into contact with the ground. On this surface 109a, which for simplicity is shown as smooth in Figure 1 , there are generally circumferential grooves connected by transverse sipes (not shown in Figure 1 ) so as to define a plurality of blocks of various shapes and sizes distributed over the rolling surface 109a.

[0251] Between the belt structure 106 and the tread band 109, an underlayer 111 may be arranged, comprising the elastomeric compound according to the invention. In the area connecting the sidewalls 108 and the tread band 109, there may optionally be a strip of elastomeric material 110, commonly known as a "mini-sidewall," generally obtained by co-extrusion with the tread band 109, which serves to improve the mechanical interaction between the tread band 109 and the sidewalls 108. Preferably, the terminal part of the sidewall 108 directly covers the lateral edge of the tread band 109.

[0252] In the case of tubeless tires, a rubber layer 112, generally known as a "liner," which provides the necessary impermeability to the inflation air of the tire, may also be present in a radially inner position with respect to the carcass layer 101 . The rigidity of the tire sidewall 108 can be improved by providing the bead structure 103 with a reinforcement layer 120, generally known as a flipper or additional insert similar to a strip. The flipper 120 is a reinforcement layer that is wrapped around the respective bead wire 102 and the bead filler 104 so as to at least partially surround them; this reinforcement layer is arranged between at least one carcass layer 101 and the bead structure 103. Usually, the flipper is in contact with at least one carcass layer 101 and with the bead structure 103.

[0253] The flipper 120 typically comprises a plurality of textile cords embedded in a layer of elastomeric material. The annular reinforcement or bead structure 103 of the tire may include an additional protective layer, generally known as "chafer" 121 or protective strip, which serves to increase the rigidity and integrity of the bead structure 103. The chafer 121 usually comprises a plurality of cords embedded in a layer of rubber made from elastomeric material. These cords are generally made from textile materials (such as aramid or rayon) or metallic materials (such as steel cords). Between the belt structure and the carcass structure, a layer or sheet of elastomeric material may be arranged. This layer may have a uniform thickness. Alternatively, the layer may have a thickness that varies in the axial direction. For example, the layer may be thicker near the outer axial edges than in the central area (crown).

[0254] Advantageously, the layer or sheet may extend over a surface substantially corresponding to the extension surface of the belt structure. The elastomeric compound according to the present invention can be advantageously incorporated into one or more of the above-mentioned tire components, preferably in the tread band, underlayer, sidewall, bead filler, and / or anti-abrasive strip.

[0255] According to an embodiment not shown, the tire may be a motorcycle tire, typically a tire with a highly curved tread.

[0256] The manufacturing of tire 100, as described above, can be carried out by assembling the respective semi-finished products suitable for forming the tire components on a forming drum (not shown), using at least one assembly device.

[0257] At least part of the components intended to form the carcass structure of the tire can be built and / or assembled on the forming drum. In particular, the forming drum is intended to first receive any liner layer and then the carcass structure. Subsequently, the devices (not shown) coaxially fit one of the annular anchoring structures around each of the plies, position an outer sleeve comprising the belt structure and the tread band in a coaxially centered position around the cylindrical sleeve of the carcass, and shape the carcass sleeve into a toroidal configuration by means of a radial expansion of the carcass structure, so as to apply it against an internal radial surface of the outer sleeve.

[0258] After the building of the green tire, a molding and vulcanization treatment is carried out to achieve the structural stabilization of the tire through the vulcanization of the cross-linkable elastomeric compositions contained therein, as well as to imprint the desired tread pattern on the tread band and any distinctive graphic marks on the sidewalls.

[0259] EXPERIMENTAL PART

[0260] Materials

[0261] This section lists all the materials used in Examples 1-8 described below.

[0262] The elastomeric polymers used are:

[0263] - poly(1 ,4-cis-isoprene) (NR), solid natural rubber SIR20 by Eatern GR Thailand - Chonburi. Mooney viscosity (ML(1 +4) at 100°C): 73 MU;

[0264] - solution butadiene-styrene rubber (S-SBR), SPRINTAN™ SLR 4602 by Trinseo;

[0265] - poly( 1 ,4-cis-butadiene) (butadiene rubber, BR) Europrene Neocis® by Polimeri Europa.

[0266] Carbon black (CB) used is selected from:

[0267] -1N375 by Cabot Corporation;

[0268] -2N234 by Cabot Corporation;

[0269] -3N550 by Birla Carbon.

[0270] The resin used is selected from: -4Kristalex by Eastman Chemical Company;

[0271] -5Escorez® 1102 by ExxonMobil.

[0272] The oil used is selected from:

[0273] -6Naphthenic oil NYTEX 4700 by Nynas;

[0274] -7TDAE (“Treated distillate aromatic extracts”) by H&R Olwerke Schindler GmbH.

[0275] Other ingredients for the preparation of the elastomeric compositions:

[0276] - Maltol by Sigma Aldrich;

[0277] - Ethyl maltol by Sigma Aldrich;

[0278] - Quercetin by Sigma Aldrich;

[0279] - Hydrated catechin by Sigma Aldrich;

[0280] - Stearic acid by llndesa;

[0281] - Silica: Zeosil® 1165 MP by Solvay;

[0282] - ZnO by Zincol Ossidi;

[0283] - 6PPD ((1 ,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine) SantoflexTM by Flexsys;

[0284] - Wax: RIOWAX BN01 by SER S.p.A.;

[0285] - TBBS (N-tert-butyl-2-benzothiazole sulfenamide) Vulkacit® NZ / EGC by Lanxess;

[0286] - TMQ (2,2,4-Trimethyl-1 ,2-dihydroquinoline) NAUGARD Q by CHEMTURA CORPORATION;

[0287] - TESPT (bis[3-(triethoxysilyl)propyl] tetrasulfide) by Evonik Industries AG;

[0288] - TESPD ((bis(S-triethoxysilylpropyl) disulfide)) by JINGDEZHEN HUNG PAI;

[0289] - 4,6-bis(octylthiomethyl)-o-cresol (67% active supported on amorphous silica), IRGANOX 1520 by BASF;

[0290] - 4,6-bis(octylthiomethyl)-o-cresol (100% active), IRGANOX 1520 L by BASF;

[0291] - Soluble sulfur by Zolfindustria (Italy);

[0292] Insoluble sulfur (67%) by Flexsys Verkauf GmbH;

[0293] - Thioperoxydicarbonic diamide, ISOBUTYL TUADS® (TiBTD) by Shandong Yanggu Huatai Chemical Co., Ltd;

[0294] - CBS (N-cyclohexyl-2-benzothiazole sulfenamide) by General Quimica;

[0295] - Masterbatch NR 25phr MWCNT by KUMHO PETROCHEMICAL.

[0296] Analysis methods Scorch time

[0297] The measurement was carried out according to ISO 289-2 (1994), at a temperature of 127°C.

[0298] Mooney viscosity

[0299] The measurement was carried out according to the procedure specified in ISO 289-1 (1994), at 100°C, on the final elastomeric composition before vulcanization.

[0300] MDR Rheometric Analysis

[0301] The tests were carried out according to ISO 6502 using an MDR2000 Alpha Technologies rheometer, at 170 °C for 20 minutes, with an oscillation frequency of 1 .66 Hz (100 oscillations per minute) and an oscillation amplitude of ± 0.5°. The time required to reach an increase of two rheometric units (Ts2) and to reach 30% (T30), 60% (Teo), 90% (Too), 95% (T95), and 100% (T100) of the maximum torque (MH) were measured. The maximum torque (MH) and the minimum torque (ML) were also measured.

[0302] IRHD Hardness

[0303] The IRHD hardness (23°C) was measured on the vulcanized elastomeric compositions according to ISO 48:2007.

[0304] Ring Tensile Tests

[0305] The tests were conducted according to ISO 8496. The force was measured at different elongations (50%, 100%, and 300%, respectively indicated as Ca0.5, Ca1 , Ca3). The tensile strength (indicated as “TS”) and the elongation at break (indicated as “EAB”) were also measured.

[0306] Dynamic Mechanical Analysis (MTS)

[0307] The dynamic mechanical properties were measured using an Instron dynamic device in tension-compression mode, according to the following methods. A specimen of the cross-linked elastomeric composition with a cylindrical shape (length = 25 mm; diameter = 12 mm) and maintained at the set temperature (23, 70 °C, and 100°C) for the entire duration of the test, was preloaded by compression up to a longitudinal deformation of 25% relative to the initial length and then subjected to a dynamic sinusoidal deformation with an amplitude of ±3.5% relative to the preloaded length, at a frequency of 100 Hz. The dynamic mechanical properties are expressed in terms of storage modulus (E’) and loss factor (Tan delta). The tan delta value is calculated as the ratio between the loss (E”) and the storage modulus (E’). Dynamic Test with RPA (Rubber Process Analyzer)

[0308] This test was used to measure the dynamic parameters of a cross-linked compound and the curing kinetics, the Payne effect (dG1) by means of Strain Sweep, G', and Tan delta at 9% strain. The procedure included the following steps and conditions

[0309] - Curing of the sample for 10 minutes at 170 °C under dynamic conditions (frequency 1.66 Hz, oscillation angle 0.5°C).

[0310] - Waiting for 10 minutes to ensure the material recovers after curing and reaches a temperature of 70 °C,

[0311] - Strain Sweep from 0.3% to 10% at 10 Hz and 70 °C,

[0312] - Mechanical preconditioning of 100 cycles at 70 °C, 10 Hz, and 9% strain,

[0313] - Dynamic characterization at 70 °C, 10 Hz, at 9% strain.

[0314] Ozone test (static and dynamic)

[0315] For the static ozone test, the tests were conducted according to ISO 1431 -1 , using air containing 50 pphm of ozone, for 70 hours at 50°C, with 20% deformation. Dynamic ozone test

[0316] Fot the dynamic ozone test, the tests were conducted according to ISO 1431 -1 , using air containing 50 pphm of ozone, for 70 hours at 50°C, with 20% strain at 0.5 Hz. The specimens were visually examined for cracks.

[0317] Resistivity

[0318] The resistivity measurement was performed according to ISO 14309, following both surface and volume methods.

[0319] Below, Table 1 summarizes the measured properties above.

[0320] Tablel

[0321] EXAMPLES

[0322] Starting from the formulations shown in Tables 2, 4, 6, 8, and 10, the corresponding compounds were prepared according to the following process.

[0323] The mixing of the components was carried out in a multi-step process using an internal Banbury-type mixer.

[0324] As an example, the detailed procedure for preparing the compositions of Example 1 is described below.

[0325] Step 1 a: 15 phr of NR, 55 phr of SBR, and 30 phr of BR were introduced into a Banbury- type internal mixer, at a chamber temperature of 40°C, with a rotor speed of 75 rpm. Silica and silane were then added, and the mixture was mixed for 45 seconds. Stearic acid, wax, carbon black, additional silica, naphthenic oil, and resin were added and mixed for 60 seconds before the compound was unloaded.

[0326] Step 1 b: After 24 hours, the compounds were reloaded into the internal mixer at a chamber temperature of 40°C with a rotor speed of 75 rpm. Zinc oxide, TMQ, 6PPD, silica, and 4,6-bis(octylthiomethyl)-o-cresol were further mixed for 120 seconds before being unloaded.

[0327] Step 2: After 24 hours, the compounds were reloaded into the Banbury mixer at a chamber temperature of 50°C with a rotor speed of 50 rpm, together with the vulcanizing bundle (TiBTD, CBS, sulfur) and maltol, quercetin, and hydrated catechin, when present, and discharged after 120 seconds of mixing.

[0328] Example 1 : Silica-based tread compound

[0329] The elastomeric composition of Example 1 (“Ex. 1”) was prepared by melt- mixing, according to the qualitative and quantitative composition shown below in Table 2.

[0330] The elastomeric composition of Example 1 was compared with an analogous composition without maltol (Comparative Example 1 , “Comp. Ex. 1”), as well as with a composition in which maltol was replaced with the same concentration of quercetin (Comparative Example 2, “Comp. Ex. 2”).

[0331] Below, for comparison purposes, the structural formulas of maltol and quercetin are provided.

[0332] Table 2

[0333] 1N375 by Cabot Corporation;4Kristalex by Eastman Chemical Company;6Naphtenic oil NYTEX 4700 by Nynas.

[0334] Measured properties for the silica-based tread compound

[0335] The characteristics of the elastomeric compounds obtained from the compositions of Example 1 and Comparative Examples 1 and 2 are summarized below in Table 3.

[0336] Table 3

[0337]

[0338] The results obtained for Example 1 showed:

[0339] - an improved scorch time compared to the composition of Comparative Example

[0340] 1 , which did not contain maltol; in contrast, the composition of Comparative Example 2 showed a marked worsening of scorch time;

[0341] - a Mooney viscosity comparable to that of Comparative Example 1 , whereas Comparative Example 2 showed a significant increase in viscosity;

[0342] - a slower vulcanization kinetics in the initial step (higher Ts2 and T30), compared to Comparative Example 1 , indicating better processability of the compound;

[0343] - a faster vulcanization kinetics at longer times (T90 and T95) compared to Comparative Examples 1 and 2, indicating a resolution of the “marching modulus” problem;

[0344] - a higher level of static reinforcement (Ca0.5, Ca1 , Ca3) compared to Comparative Examples 1 and 2, with a slight decrease in breaking properties (TS, EAB); and

[0345] - improved ozone resistance compared to Comparative Examples 1 and 2.

[0346] Examples 2-4: Silica-based tread compound

[0347] Each elastomeric composition of Examples 2-4 (“Ex. 2-4”) was prepared by melt-mixing, according to the qualitative and quantitative composition shown below in Table 4.

[0348] It should be noted that the elastomeric compound of Example 2 was compared with the analogous compound of Comparative Example 3 (“Comp. Ex. 3”), in which maltol is absent. Compared to the formulation of Example 2, in the compound of Example 3 the anti-aging agent bundle (TMQ, 6PPD, and paraffinic and hydrocarbon wax) was replaced with 4,6-bis(octylthiomethyl)-o-cresol (Irganox 1520 L, 100% active), at a concentration of 4.5 phr, while in the formulation of Example 4 the concentration of maltol was also doubled, from 1 .7 phr (Examples 2 and 3) to 3.4 phr (Ex. 4). The compounds of Examples 3 and 4 were therefore compared with that of Comparative Example 4 (“Comp. Ex. 4”), in which maltol is absent.

[0349] Table 4

[0350] 1N375 by Cabot Corporation;4Kristalex by Eastman Chemical Company;6Naphtenic oil NYTEX 4700 by Nynas.

[0351] Measured properties for the silica-based tread compounds

[0352] The characteristics of each of the elastomeric compounds obtained from the compositions of Examples 2-4 and Comparative Examples 3 and 4 are summarized below in Table 5.

[0353] Table 5

[0354] The results obtained for Example 2 showed:

[0355] - a slower vulcanization kinetics, compared to Comparative Example 3, in the initial step (higher TS2 and T30), indicating the maintenance and / or improvement of the compound’s processability;

[0356] - a significantly faster vulcanization kinetics, compared to Comparative Example 3, at longer times (lower T90 and T95), indicating a resolution of the “marching modulus” problem;

[0357] Moreover, the dynamic modulus (E1) and Tan Delta data for Example 2 indicated a stiffening at all temperatures, and a reduction in hysteresis at higher temperatures (70 °C and 100 °C), compared to Comparative Example 3.

[0358] As previously described, Comparative Example 4 refers to a compound in which the anti-aging agent bundle (wax, 6PPD, and TMQ), present in the formulations of Example 2 and Comparative Example 3, was replaced with 4,6-bis(octylthiomethyl)-o- cresol (IRGANOX 1520 L, 67% active), resulting in improved kinetics compared to Comparative Example 3 but lower static and dynamic modulus values, as well as a significant worsening of both static and dynamic ozone resistance.

[0359] That said, the presence of maltol in the formulations of Examples 3 and 4 showed, compared to Comparative Example 4, the following:

[0360] - the vulcanization kinetics were slower in the initial step (higher Ts2 and T30), indicating better processability of the compound, and progressively accelerated at longer times (lower T90 and T95), indicating a resolution of the “marching modulus” problem. This effect can be observed in the graph of Figure 2, where the vulcanization curves of the compositions of Example 4 (dotted line) and Comparative Example 3 (solid line) are compared. In particular, Figure 2 shows that the vulcanization curve of Example 4 of the invention displays: 1 ) a slower trend in the initial steps of vulcanization (at times less than about 145 s), compared to the curve of Comparative Example 3; and 2) a faster trend in the subsequent steps of vulcanization (at times greater than about 145 s), reaching the plateau in a shorter time compared to the curve of Comparative Example 3, which continues to rise without ever reaching the plateau, a behavior typical of compounds exhibiting the “marching modulus” problem.

[0361] - MH was higher, at equal ML, indicating greater effectiveness of the vulcanizing agents in the presence of maltol;

[0362] - ozone resistance was improved, surprisingly in line with Comparative Example 3 in the static ozone test, despite the absence of wax and 6PPD;

[0363] - the static and dynamic moduli progressively increased, without compromising the breaking properties (TS and EAB) of the compound;

[0364] - cold hysteresis (23°C, 100 Hz) progressively increased, indicating a possible improvement in braking and wet performance of the tire containing such a tread compound;

[0365] - hot hysteresis (70°C and 100°C, 100 Hz) remained substantially in line with that of Comparative Example 4, particularly for Example 3, i.e., at a maltol concentration of 1 .7 phr.

[0366] Example 5: Tread compound based on carbon black and silica

[0367] The elastomeric composition of Example 5 (“Ex. 5”) was prepared by meltmixing, according to the qualitative and quantitative composition shown below in Table 6.

[0368] The formulation of Example 5 was compared with an analogous compound in which maltol (3-hydroxy-2-methyl-4-pyrone) is absent (Comparative Example 5, “Comp. Ex. 5”).

[0369] Table 6

[0370] 2N234 by Cabot Corporation;4Kristalex by Eastman Chemical Company;7TDAE (“Treated distillate aromatic extracts”) by H&R Olwerke Schindler GmbH.

[0371] Measured properties for the tread compound based on carbon black and silica The characteristics of each of the elastomeric compounds obtained from the compositions of Example 5 and Comparative Example 5 are summarized below in Table 7.

[0372] Table 7

[0373]

[0374] The results obtained for Example 5 showed:

[0375] - higher dynamic moduli, with substantially comparable hysteresis and only a minimal loss of breaking properties, compared to Comparative Example 5;

[0376] - overall improved vulcanization kinetics; specifically: o kinetics in line with those of Comparative Example 5 in the initial step (lower TS2 and T30), indicating maintained or improved processability of the compound; o faster kinetics, compared to Comparative Example 5, at longer times (lower T90, T95, and T100), indicating a resolution of the “marching modulus” problem; o a higher MH value, with a substantially equal (or slightly reduced) ML, compared to Comparative Example 5, indicating greater reinforcement;

[0377] - significantly higher static and dynamic modulus values (consistent with a higher MH value), compared to those of Comparative Example 5, with only a minimal decrease in tensile strength;

[0378] - hysteretic properties substantially in line with those of Comparative Example 5, thus showing an improved modulus / hysteresis ratio, which could potentially be exploited to obtain compounds with equal modulus and reduced hysteresis.

[0379] Example 6: Carbon black-based compound

[0380] The elastomeric composition of Example 6 (“Ex. 6”) was prepared by meltmixing, according to the qualitative and quantitative composition shown below in Table 8.

[0381] The elastomeric compound of Example 6 was compared with an analogous compound in which maltol is absent (Comparative Example 6, “Comp. Ex. 6”), as well as with an analogous compound in which maltol was replaced with quercetin in the same concentration (Comparative Example 7, “Comp. Ex. 7”).

[0382] Table 8

[0383] 3N550 by Birla Carbon;5Escorez® 1102 by ExxonMobil.

[0384] Measured properties for the carbon black-based compounds The characteristics of each of the elastomeric compounds obtained from the compositions of Example 6 and Comparative Examples 6 and 7 are summarized below in Table 9. Table 8

[0385] The results obtained for Example 6 showed:

[0386] - faster kinetics compared to Comparative Examples 6 and 7 at all times;

[0387] - a higher MH value compared to Comparative Example 6, with a substantially equal ML;

[0388] - a higher dynamic shear modulus compared to Comparative Example 6, with comparable hysteresis;

[0389] - an improvement in ozone resistance in the dynamic test compared to Comparative Example 7, in the presence of quercetin. Examples 7 and 8: Compound with carbon nanotubes

[0390] Each of the elastomeric compositions of Examples 7 and 8 (“Ex. 7-8”) was prepared by melt-mixing, according to the qualitative and quantitative composition shown below in Table 10.

[0391] The formulations of Examples 7 and 8 differ from each other only in that they contain, respectively, maltol (Example 7) and ethyl maltol (Example 8). These elastomeric compositions were compared with an analogous compound in which both maltol and ethyl maltol are absent (Comparative Example 8, “Comp. Ex. 8”).

[0392] Table 10

[0393] 5Escorez® 1102 by ExxonMobil.

[0394] AMasterbatch based on NR containing 25 phr of multi-walled carbon nanotubes (MWCNT). Note that the 12.5 phr of masterbatch included in the formulations of Examples 7 and 8 comprise 10 phr of NR and 2.5 phr of MWCNT.

[0395] Measured properties for the silica-based tread compounds The characteristics of each of the elastomeric compounds obtained from the compositions of Examples 7 and 8 and Comparative Example 8 are summarized below in Table 11.

[0396] Table 11 The results obtained for Examples 7 and 8 showed:

[0397] - vulcanization kinetics comparable to those of the compound of Comparative Example 8; - higher MH values, at equal ML, compared to the compound of Comparative Example 8, indicating greater reinforcement;

[0398] - a higher static modulus than that of Comparative Example 8, while maintaining substantially unchanged breaking properties; - dynamic moduli, both in shear and compression, higher than those of

[0399] Comparative Example 8, with substantially comparable hysteresis;

[0400] - higher hardness than that of Comparative Example 8, further confirming the increased reinforcement;

[0401] - substantially unchanged electrical conductivity.

Claims

CLAIMS1 . Cross-linkable elastomeric composition, comprising: a) one or more elastomeric polymers; b) a compound of formulawhereinX1is selected from the group consisting of: hydrogen, 0, N-R5, or S, wherein, if X1is hydrogen, R1is absent;Y is selected from the group consisting of: N-R6, 0, or S;Z is 0 or S; and whereinR1, R5and R6are independently selected from the group consisting of: hydrogen, C1-C20 acyl, linear or branched C1-C20 alkyl, linear or branched C1- C20 hydroxyalkyl, linear or branched C2-C6 alkenyl or alkynyl, aryl, linear or branched C1-C6 alkyl-aryl, linear or branched C2-C6 alkenyl-aryl, linear or branched C2-C6 alkynyl-aryl, and heteroaryl; andR2, R3and R4are independently selected from the group consisting of: hydrogen, hydroxyl, C1-C20 ester, linear or branched C1-C20 alkoxyl, linear or branched C1-C6 alkyl, linear or branched C1-C6 hydroxyalkyl, linear or branched C2-C6 alkenyl or alkynyl, aryl, linear or branched C1-C6 alkyl-aryl, linear or branched C2-C6 alkenyl-aryl, linear or branched C2-C6 alkynyl-aryl, and heteroaryl; c) at least one reinforcing filler; e d) a cross-linking system.

2. Composition according to claim 1 , wherein R1, R5and R6are independently selected from the group consisting of: hydrogen, C1-C6 acyl, linear or branched C1-C6 alkyl, linear or branched C1-C6 hydroxyalkyl, linear or branched C2-C6 alkenyl or alkynyl, aryl, linear or branched C1-C6 alkyl-aryl, linear or branched C2-C6 alkenyl-aryl, linear or branched C2-C6 alkynyl-aryl, and heteroaryl; andR2, R3and R4are independently selected from the group consisting of: hydrogen, hydroxyl, linear or branched C1-C6 alkoxyl, linear or branched C1-C6 alkyl, linear or branched C1-C6 hydroxyalkyl, linear or branched C2-C6 alkenyl or alkynyl, aryl, linear or branched C1-C6 alkyl-aryl, linear or branched C2-C6 alkenyl-ary I , linear or branched C2-C6 alkyny l-ary I, and heteroaryl.

3. Composition according to claim 1 or 2, wherein X1is 0.

4. Composition according to any one of claims from 1 to 3, wherein Y is 0.

5. Composition according to any one of claims from 1 to 4, wherein Z is 0.

6. Composition according to any one of claims from 1 to 5, wherein:R2and R3are independently selected from the group consisting of: hydrogen, hydroxyl, linear or branched C1-C6 alkyl, linear or branched C1-C6 hydroxyalkyl, preferably hydroxymetyl; andR4is hydrogen.

7. Composition according to claim 6, wherein:R2is selected from linear or branched C1-C6 alkyl, preferably methyl and ethyl, more preferably is methyl;R3is selected from hydrogen, linear or branched C1-C6 alkyl, preferably methyl or ethyl, more preferably is hydrogen; andR4is hydrogen.

8. Composition according to claim 1 , wherein the compound of formula (I) is represented by at least one of the following formulas:.

9. Composition according to claim 1 , wherein the compound of formula (I) is represented by the following formula (XI):whereinR7is linear or branched C1-C19 alkyl, preferably linear C4-C17 alkyl, or linear or branched C2-C19 alkenyl, preferably linear C15-C19 alkenyl.

10. Composition according to any one of claims from 1 to 9, wherein the compound of formula (I) is in an amount of at least 0.1 phr.11 . Composition according to any one of claims from 1 to 10, wherein at least one of said one or more elastomeric polymers is an unsaturated elastomeric polymer selected from the group consisting of: natural and / or synthetic cis-1 ,4- polyisoprene, polybutadiene, preferably polybutadiene with a high content of monomeric cis-1 ,4 units or polybutadiene with a high content of monomeric 1 ,2- butadiene units, isoprene / isobutene copolymers, preferably halogenated isoprene / isobutene copolymers, preferably butyl rubber, more preferably halogenated butyl rubber, even more preferably chlorobutyl rubber orbromobutyl rubber, styrene / 1 ,3-butadiene copolymers, styrene / isoprene / 1 ,3- butadiene copolymers, partially hydrogenated styrene-1 ,3-butadiene, and mixtures thereof.

12. Composition according to any one of claims from 1 to 11 , wherein the at least one reinforcing filler is selected from the group consisting of: sp2-hybridized carbon allotrope, silica, layered silicates, magnesium silicates optionally modified, mixed aluminum and magnesium oxides with lamellar structure, alumina, aluminium silicates, and mixtures thereof.

13. Composition according to claim 12, wherein said sp2-hybridized carbon allotrope is selected from the group consisting of: carbon black, graphene, 2- layer graphene, 3 to 10 layers graphene, graphite, preferably high surface area graphite, single-walled or multi-walled carbon nanotubes, carbon nanotubes of longitudinal or helical extension, nanocones, nanocorns, nanotoroids, fullerene, and mixtures thereof.

14. Composition according to claim 12, wherein said sp2-hybridized carbon allotrope is carbon black.

15. Composition according to claim 14, wherein carbon black is in an amount of at least 10 phr.

16. Composition according to any one of claims from 1 to 12, wherein said at least one reinforcing filler is silica or a mixture of sp2-hybridized carbon allotrope, preferably carbon black, and silica.

17. Composition according to claim 16, wherein silica is in an amount of at most 130 phr.

18. Composition according to any one of claims from 1 to 17, wherein said at least one reinforcing filler is in an amount comprised between 10 and 150 phr.

19. Composition according to any one of claims from 1 to 18, comprising one or more additives, said one or more additives being selected from the group consisting of: anti-aging agents, plasticizers, adhesives, modifying resins, coupling agents, and mixtures thereof.

20. Composition according to claim 19, wherein said anti-aging agents are selected from the group consisting of:• at least one antioxidant, preferably at least one quinoline antioxidant, more preferably TMQ, and / or a phenolic antioxidant, preferably 4,6- bis(octylthiomethyl)-o-cresol;• at least one antiozonant, preferably selected from at least one p- phenylenediamine (PPD), and / or at least one static protective agent selected from a wax and / or a polymeric static protective agent, said at least one p-phenylenediamine being preferably selected from the group consisting of: N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N-(1 ,3- dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N, N'-bis-(1 ,4- dimethylpentyl)-p-phenylenediamine (77PD), N,N'-bis-(1 -ethyl-3-methyl- pentyl)-p-phenylenediamine (DOPD), N, N'-bis-(1 ,4-dimethyl-pentyl)-p- phenylenediamine, N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'- ditolyl-p-phenylenediamine (DTPD), N,N'-di-beta-naphthyl-p- phenylenediamine (DNPD), N,N'-bis(1 -methylethyl)-p- phenylenediamine, N,N'-di-sec-butyl-p-phenylenediamine (44PD), N- phenyl-N-cyclohexyl-p-phenylenediamine, N-phenyl-N'-1 -methylethyl-p- phenylenediamine and the like, and mixtures thereof, even more preferably is N-(1 ,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD); and• mixtures thereof, preferably a mixture of TMQ, wax and 6PPD.21 . Composition according to claim 19 or 20, wherein the at least one antioxidant and / or the at least one antiozonant are in an amount of at least 0.1 phr and of at most 20 phr.

22. Composition according to claim 20 or 21 , wherein the at least one p- phenylenediamine is in an amount equal to or less than 2.0 phr or it is absent.

23. Composition according to any one of claims from 1 to 22, wherein the crosslinking system comprises:- at least one cross-linking agent, preferably selected from sulfur and / or sulfur-donor; and, preferably- at least one cross-linking activator, preferably selected from the group consisting of: ZnO, ZnCOs, zinc salts of saturated or unsaturated fatty acids comprising 8 to 18 carbon atoms, and mixtures thereof; and / or- at least one cross-linking accelerator; and / or- at least one cross-linking retarder.

24. Composition according to any one of claims from 19 to 23, wherein the plasticizers comprise at least one oil selected from the group consisting of: mineral oils, vegetable oils, synthetic oils, and mixtures thereof, preferably aromatic oils, naphthenic oils, soybean oils, and mixtures thereof, more preferably naphthenic oils.

25. Composition according to any one of claims from 19 to 24, wherein the modifying resins comprise at least one resin selected from the group consisting of: hydrocarbon resin, phenolic resin, natural terpenic resin, natural rosin resin, and mixtures thereof, preferably hydrocarbon resin.

26. Composition according to any one of claims from 19 to 25, wherein the coupling agents comprise at least one silane coupling agent, preferably selected from bis(3-triethoxysilylpropyl)tetrasulfide and bis(3-triethoxysilylpropyl)disulfide.

27. Process for preparing an elastomeric compound, comprising the following steps: i) providing said one or more elastomeric polymers, said compound of formula (I), said at least one reinforcing filler, said cross-linking system, and optionally one or more additives, of the cross-linkable elastomeric composition according to claims from 1 to 26; and ii) carrying out at least one mixing step.

28. Tire component comprising an elastomeric compound prepared by the process according to claim 27.

29. Tire for vehicle wheels comprising at least one tire component according to claim 28.

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