Tires for vehicle wheels comprising sustainable polymers

Abstract

The present invention relates to a vulcanizable elastomeric composition comprising a diene elastomeric polymer, a reinforcing filler, at least one vulcanizing agent, and an amorphous polyester obtained by the copolymerization of at least one diol, preferably at least two diols, at least one dicarboxylic acid, preferably at least two dicarboxylic acids, more preferably three dicarboxylic acids, and optionally at least one hydroxycarboxylic acid or cyclic lactones thereof, as defined in the description, and to a tire for vehicle wheels or a green structural component thereof comprising such a vulcanizable elastomeric composition.

Description

[0001] TITLE

[0002] “Tires for vehicle wheels comprising sustainable polymers”

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to vulcanizable elastomeric compositions comprising sustainable polymers suitable for the production of tire for vehicle wheels, and to a tire for vehicle wheels comprising at least one structural component comprising a vulcanized elastomeric compound obtained by vulcanizing a vulcanizable elastomeric composition comprising such sustainable polymers.

[0005] PRIOR ART

[0006] A tire for vehicle wheels typically comprises a carcass structure comprising at least one carcass layer having opposite lateral edges associated with respective bead structures, a belt structure applied in a radially external position to the carcass structure, a pair of sidewalls applied laterally on the opposite sides with respect to the carcass structure, and a tread band disposed in a position radially external to the belt structure.

[0007] The carcass structure is designed, in addition to supporting the weight of the vehicle, to resist the inflation pressure and all the lateral and longitudinal stresses to which the running tire is subjected following contact with the road surface.

[0008] The belt structure is designed to transfer the above-mentioned lateral and longitudinal stresses to the carcass structure and helps to confer the desired features of structural strength, grip, driving stability, controllability, directionality, road grip, comfort and to maintain these performances over time.

[0009] The bead structures are designed to withstand the circumferential, transverse, and combined stresses that are transmitted between the wheel rim and the tire during normal conditions of use, for example in acceleration, braking and when turning, possibly even at high speed.

[0010] The sidewall construction are designed to balance flexibility, structural strength and protection to ensure optimal performance, durability and riding comfort.

[0011] The tread band is designed to confer the desired features of dry and wet grip, driving comfort, fuel efficiency, handling and stability, and to maintain such features throughout the life of the tire.

[0012] The several structural components of a finished tire comprise a vulcanized elastomeric compound. The matrix of vulcanized elastomeric compound is made through the vulcanization of an elastomeric composition comprising at least one diene elastomeric polymer, and at least one reinforcing filler in order to improve the features of the cross-linked products obtained, in particular the mechanical properties.

[0013] Typical elastomers for dynamic-mechanical applications, such as those in tire compounds, are poly(1 ,4-cis-isoprene) from natural sources (natural rubber, NR) and from Ziegler-Natta polymerization (isoprene rubber, IR), poly(1 ,4-cis-butadiene), poly(styrene-co-butadiene), from emulsion (E-SBR) and solution (S-SBR) polymerization, poly(isobutene-isoprene), optionally halogenated. The 1 ,4-cis unit of a hydrocarbon monomer is strategic to have high elasticity. Fortunately, the most important elastomer, natural rubber, has this feature and comes from natural sources.

[0014] However, all the mentioned elastomers have a major flaw that they are not hydrolysable and thus are not readily biodegradable and / or compostable.

[0015] This is indeed a major technical problem. According to the International Union for Conservation of Nature and Natural Resources, an organization which has observer and consultative status at the United Nations, the particles from tire abrasion, so called tire debris, account for about 30% of the primary microplastics in the environment and in the oceans, the second largest source of microplastics after textile fibers (IUCN. Primary Microplastics in the Oceans: A Global Evaluation of Sources. 2017. Authors: Julien Boucher, Damien Friot), https: / / portals.iucn.org / library / sites / library / files / documents / 2017-002-En.pdf.

[0016] It would be highly desirable to reproduce the properties of elastomers suitable for dynamic-mechanical applications, such as those in tire compounds, with elastomers which could be hydrolysable, readily biodegradable, or compostable.

[0017] It would be desirable to prepare these elastomers from natural sources.

[0018] These elastomers should substitute the traditional hydrocarbon elastomers, which are not readily biodegradable or compostable or should partially replace them.

[0019] Hence, it would be desirable to have compatibility of the sustainable biodegradable / compostable polymers with the traditional hydrocarbon elastomers. They should be crosslinkable with the same crosslinking system. In the case of compounds for tires, they should be crosslinkable with sulfurbased systems. Moreover, they should be reinforced with all the traditional fillers used to reinforce the traditional hydrocarbon elastomers, mainly carbon black and silica.

[0020] Due to its high reinforcing efficiency, carbon black is a particularly used reinforcing filler. However, carbon black represents a non-renewable raw material, deriving mainly from partial combustion processes of fossil fuels, mainly naphtha, methane gas, and other hydrocarbons. In addition, carbon black can be of environmental concern as it is a potential pollutant if not properly disposed of. The replacement or reduction of the use of carbon black therefore represents an objective not only of interest for tire manufacturers, but of common interest for the community.

[0021] Silica is used as reinforcing filler, in place of or together with carbon black, to have mechanical reinforcement and low dissipation of energy. Silica has reactive silanol groups on its surface and, thanks to the use of a coupling agent, typically a silane containing sulfur atoms, a chemical bond is formed between silica and the elastomers’ chains. This leads to the reduction of the filler network, i.e. of the filler-filler interactions, which are reversible and promote the energy dissipation of the elastomer compounds which experience dynamic-mechanical stresses. Hence, silica has been increasingly used in tire compounds over the last decades. Moreover, silica sourced from renewable feedstock such as rice husk is emerging as an available industrial product.

[0022] However, silica is characterized by significant flaws. Silica leads to the increase of the compound viscosity, to the worsening of processability and to the shortening of the storage time of the compounds. Such drawbacks arise from the surface activity of silica because the polar groups promote extensive supramolecular interactions. A shorter storage time results in the need for a specific planning for the compounds’ production and the procedures for storing and moving the compounds, with a clear impact on the logistics. Moreover, to achieve efficient mixing of silica-based compounds, specific energy and cost intensive mixing equipment are required. Due to the use of a silane, silica- based compounds have increased adhesiveness to the metal parts of the mixing machines, and this requires special treatments of the metal surfaces. Finally, silica is abrasive, and this as well requires special treatments of the metal surfaces and the revision of the maintenance procedures. These drawbacks are relevant at the industrial scale, for example when silica based elastomeric compounds are used for tire compounds. To obtain higher dynamic-mechanical reinforcement, a greater amount of silica is used. The hysteresis does not increase as much as in the case of carbon black, but the mentioned drawbacks do.

[0023] However, tire compounds, particularly those used for tire treads, are typically almost exclusively based on silica as the reinforcing filler and increasing research efforts are made to use silica in place of carbon black, also in tire compounds other than the tire tread. This is because the prevailing objective is the reduction of energy dissipation of a rolling tire.

[0024] It would be thus highly desirable to obtain the same properties of a silica- based compound by reducing the amount of silica. More in particular, it would be desirable to introduce a material able to increase the mechanical reinforcement of the compound, mainly the dynamic rigidity, without enhancing the hysteresis and thus opening a route to reduce the amount of silica matching the desired mechanical properties and even improving hysteresis, especially in the temperature range corresponding to rolling resistance prediction. It would be desirable to achieve this objective without appreciably modifying the formulation of the elastomer compound, definitely without adding a further filler. It would be desirable if this objective could be achieved by adding a further ingredient in a minor amount. In consideration of the beneficial effect of the reactivity with the elastomer chains of the compound ingredients, it could indeed be desirable to add a minor ingredient able to react with the elastomer chains, typically in the vulcanization step.

[0025] In the prior art, it has been reported the addition of minor reactive ingredients, to modify the dynamic-mechanical properties of a compound, particularly of a silica-based compound. Typically, they are low molecular weight polymers (oligomers) of 1 ,3-butadiene and styrene, homo- and copolymers. They are used in place of processing oils.

[0026] In US2007135564, a sulfur-vulcanizable rubber compound for tire treads, with a large amount of silica, contains a liquid polybutadiene with a molecular weight of 1500-1000 g / mol and a vinyl content of 15-50%. By replacing a processing oil with the liquid polybutadiene, a moderate increase of tensile properties was obtained. The amount of silica is the same in all the compounds.

[0027] In US4840988, a liquid BR which flows below 20°C is used in place of a softening agent (aromatic oil, naphthenic oil) in a compound based on carbon black as the reinforcing filler. At equal amount, the hardness is very similar or even the same.

[0028] In US2013289197, a liquid polybutadiene rubber, with a number average molecular weight from 500 to 9000 g / mol is in a compound with a large amount of silica. What is claimed is the improvement of abrasion and rolling. It is not shown any improvement of the mechanical reinforcement and the amount of silica is the same in all the compounds.

[0029] In WO2017 / 046771 , the compound should have a lower Tg and higher hysteresis between - 10°C and 0°C and higher dynamic rigidity at T>70°C. This objective is achieved by using a liquid rubber, such as low molecular weight poly(butadiene) and poly(isoprene) and a resin. The liquid rubber is responsible for the low temperature properties, whereas the resin, which is a polymer which cannot be crosslinked, for example a hydrocarbon or phenolic resin, gives the high temperature rigidity. Hence, also in this prior art, the low molecular weight polymer is not able to afford high rigidity and the resin is not reactive.

[0030] In CN116444953A, a rubber composition comprising 100 phr of diene rubber, 0-70 phr of carbon black, 0-70 phr of silica, 0-7 phr of a silane coupling agent, 0.2-15 phr of a polyester, 0.5-4 phr of a vulcanizing agent and a conventional auxiliary agent is described. The data in CN116444953A, in particular considering the results of Comparative example 2 and Comparative example 4, suggest that the addition of even only 1 phr of polyester to the rubber composition led to significant changes in static properties, such as, for example, showing that stress at 300% elongation (CA3) changed from 12.4 to 14.1 MPa with a 13.7% difference.

[0031] Hence, in the examples available in the prior art, there is no teaching on how to use low molecular weight polymers to prepare compounds with substantially higher dynamic rigidity. This is due to the chemical nature of the low molecular weight polymers. They contain unsaturations and can thus react with the vulcanization system and can enter in a common network with the elastomers. However, they do not contain functional groups which could allow a direct reaction with the filler. In particular, they do not contain functional groups which could allow a direct reaction with silica as the filler. Indeed, the interaction of an unsaturated low molecular weight polymer with the filler and in particular with silica is mediated by the sulphur-based silane, as the interaction of a high molecular weight elastomer.

[0032] Moreover, the low molecular weight polymers are oil based and this has a clear impact on the environmental sustainability. Actually, the low molecular weight polymers based on 1 ,3-butadiene and styrene could be prepared from natural sources. However, their chemical structure is the same, whatever is the source of the monomer, and so their interaction with the filler and with silica remains the same.

[0033] Moreover, the low molecular weight polymers traditionally used in the prior art are not readily biodegradable or compostable. Indeed, their main chain is based on carbon-carbon bonds which cannot be hydrolyzed.

[0034] In the literature, examples of biobased polymers with a chemical structure suitable to interact with the filler were reported.

[0035] In (Macromolecules 2012, 45, 6830-6839), poly(diisoamyl itaconate-co- isoprene) elastomer was prepared by emulsion polymerization of diisoamyl itaconate and isoprene by using persulfate and redox initiators. Diisoamyl itaconate was prepared from isoamyl alcohol and itaconic acid. High molecular weight and low glass transition were obtained. Silica-reinforced compounds were prepared.

[0036] In (J. Mater. Chem. A, 2016, 4, 13058-13062), poly-(di-n-alkyl itaconate-co- isoprene) and poly(di-n-butyl itaconate-co-butadiene) were prepared through a redox initiated emulsion copolymerization. Itaconic acid was from renewable resources and aliphatic alcohols for preparing the itaconates were derived from biomass. The double bonds coming from an unsaturated comonomer allowed the reaction with a sulfur-based silane and thus the formation of a chemical bond with silica.

[0037] In (Composites Science and Technology 133 (2016) 136-156), a review of the copolymers, based on itaconates prepared in the above-mentioned works, was reported.

[0038] In (Processes 2020, 8, 1527), poly(dibutyl itaconate-co-butadiene) elastomers were prepared by emulsion copolymerization and nanocomposites were prepared by using silica and carbon black. In (Composites Part B 248 (2023) 110383), bio-based elastomers were prepared with a renewable monomer such as dimethyl itaconate and partially petroleum-derived butadiene, by emulsion copolymerization and composites were prepared with silica. The unsaturation allows the reaction with the sulfur based crosslinking system. The copolymers containing glycidyl methacrylate revealed pronounced interaction with silica.

[0039] In the above-mentioned works, the use of isoprene or butadiene was intended to “provide double bonds for the further crosslinking and increase the macromolecular flexibility of obtained polymer” (Composites Science and Technology 133 (2016) 136-156). However, the use of the diene monomers as well as of the itaconate comonomer led to a backbone chain of the elastomer based on carbon-carbon bond. Hence, the elastomer is not expected to be hydrolysable, readily biodegradable, or compostable.

[0040] In the literature, examples of sustainable polymers, potentially biobased, with a chemical structure suitable to be hydrolyzed were reported. These sustainable polymers are expected to be biodegradable or at least compostable.

[0041] In (Advanced Engineering Materials 2012, 14, No. 1 -2) and in (Composites Science and Technology 133 (2016): 136-156), potentially bio-based monomers such as sebacic acid, itaconic acid, succinic acid, 1 ,3-propanediol, and 1 ,4 butanediol were chosen to generate so called bio-based engineering elastomers through melting step growth polycondensation. Almost noncrystalline copolyester elastomers with low glass transition temperature (Tg) were obtained. The unsaturation in the polymer was from itaconic acid. Silica nanoparticles were used to achieve strengthening. Chemical crosslinking was performed with peroxide.

[0042] In (AIP Conference Proceedings 1864, 020221 (2017)), poly (butylene itaconate) (PBI) was synthesized by melt polycondensation from itaconic acid (IA) and 1 ,4-butandiol. Low molecular weight was obtained and was to some extent increased by using other comonomers, such as dimethyl terephthalate, adipic acid and sebacic acid.

[0043] In (Adv. Healthcare Mater. 2019, 8, 1900245), poly(itaconate-co-citrate-co- octanediol) was prepared by a polycondensation followed by radical crosslinking.

[0044] Sustainable polyesters prepared by high temperature melt polycondensation are reported in the prior art with the furan ring in one of the comonomers. It is well known that furan-based chemicals can be prepared from biosources.

[0045] Indeed, in (Polym. Chem., 2015, 6, 5961 -5983), sustainable polyesters and other polymers from 2,5-furandicarboxylic acid are reviewed as “a tribute to furan excellency”.

[0046] In (ACS Sustainable Chemistry & Engineering 8.11 (2020): 4400-4406.), thermoplastic furan-based copolymers are presented. However, thermoplastic materials cannot be used for elastomer compounds, particularly for tires.

[0047] Poly(hexamethylene 2,5-furanodicarboxylate)-b-poly(tetrahydrofuran) is mentioned in the review (Molecules 2021 , 26, 4454). Poly(hexamethylene 2,5- furanodicarboxylate) is indicated as a rigid block. It is reported that the polymers clearly show crystallinity. Crystallinity should not be present in an elastomer. Moreover, there is not any teaching that these polymeric structures could be crosslinked and could react with a vulcanization system.

[0048] SUMMARY OF THE INVENTION

[0049] The Applicant perceived that it would be highly desirable to use a polymer which could be hydrolysable, biodegradable or at least compostable to replace, at least partially, the traditional hydrocarbon ingredients used in an elastomeric compound for dynamic-mechanical applications, such as those for tire compounds.

[0050] The Applicant also perceived that it would be highly desirable to use a polymer, as an ingredient of an elastomeric compound, which could lead to the enhancement of the dynamic rigidity of the compound, thus allowing the reduction of the filler content, without negatively affecting the other mechanical properties. The enhancement of the dynamic rigidity and the reduction of the filler content would bring about the enhancement of properties such as the hysteresis, the ultimate tensile properties, the abrasion resistance.

[0051] It would be desirable that the hydrolysable polymer was not an oligomer and had low glass transition temperature and very low crystallinity. Ideally, the sustainable polymers should be amorphous.

[0052] It would be desirable to prepare the polymer by means of a traditional polymerization, by using the usual polymerization techniques, without having technical problems. In particular, it would be highly desirable to have high reactivity with the sulfur-based crosslinking system, without having undesired side reactions, such as radical crosslinking, during the synthesis of the polymer.

[0053] It would be desirable that the hydrolysable polymer could establish a pronounced interaction with the reinforcing filler(s), particularly with silica.

[0054] The Applicant has carried out an intense research activity in order to get the above-mentioned desires starting from the sustainable polymers known in the literature.

[0055] After extensive experimentation, the Applicant surprisingly found that certain amorphous sustainable polyesters obtained by the co-polymerization of diols and dicarboxylic acids and having a glass transition temperature ranging from -20° to -70°C and a number average molecular weight (Mn) ranging from 7,000 Da to 70,000 Da can be useful as ingredients for vulcanizable elastomeric compositions suitable for the production of tires for vehicle wheels when used in an amount of from 2% to 25% by weight with respect the total weight of the vulcanizable elastomeric composition.

[0056] The vulcanizable elastomeric composition comprising such amorphous sustainable polyesters showed several advantages compared to conventional vulcanizable elastomeric composition known in the art.

[0057] At first, the presence of a hydrolysable, likely biodegradable or at least compostable ingredient made such a vulcanizable elastomeric composition, at least partially, more sustainable from an environmental point of view.

[0058] Further, the vulcanizable elastomeric composition comprising the amorphous sustainable polyesters showed a remarkably higher crosslinking efficiency, a higher dynamic rigidity at any temperature between 10°C and 70°C and a better balance between dynamic rigidity and tensile properties, which in turn would allow to reduce the amount of filler, and therefore to have better values of Tan delta, with the obtainment of a tire with better grip, and lower rolling resistance and thus lower fuel consumption.

[0059] Therefore, in a first aspect thereof, the present invention relates to a vulcanizable elastomeric composition comprising:

[0060] (i) at least one diene elastomeric polymer selected from the group of natural and synthetic diene elastomeric polymers,

[0061] (ii) a reinforcing filler, and (iii) at least one vulcanizing agent, characterized in that said vulcanizable elastomeric composition further comprises an amorphous polyester obtained by the copolymerization of at least one diol, preferably at least two diols, at least one dicarboxylic acid, preferably at least two dicarboxylic acids, more preferably three dicarboxylic acids, and optionally at least one hydroxycarboxylic acid or cyclic lactones thereof, wherein said diol is selected from the group consisting of ethylene glycol, 1 ,3 propanediol, 1 ,2-propanediol, 1 ,4-butanediol, 1 ,3-butanediol, 1 ,2-butanediol, 2,3-butanediol, 1 ,5-pentanediol, 1 ,6-hexanediol, cis-1 ,4-butenediol, trans-1 ,4- butenediol, 1 ,8-octanediol, 1 ,10-decanediol, 1 ,12-dodecanediol, 1 ,16- hexadecanediol, and 2,5-furandimethanol, said dicarboxylic acid is selected from the group consisting of 2,5- furandicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, muconic acid, and 3,3-dithiodipropionic acid, said hydroxycarboxylic acid is selected from the group consisting of lactic acid, glycolic acid, mandelic acid and co-hydroxy acids having four to eighteen carbon atoms, wherein said polyester has a glass transition temperature ranging from -20° to -70°C and a number average molecular weight (Mn) ranging from 7,000 Da to 70,000 Da, and wherein the amount of said polyester ranges from 2% to 25% by weight with respect the total weight of the vulcanizable elastomeric composition.

[0062] In a second aspect thereof, the present invention relates to a green tire structural component comprising a vulcanizable elastomeric composition according to the first aspect of the present invention.

[0063] In a third aspect thereof, the present invention relates to a tire for vehicle wheels comprising at least one structural component comprising a vulcanized elastomeric compound obtained by vulcanizing a vulcanizable elastomeric composition according to the first aspect of the present invention. DEFINITIONS

[0064] The term “amorphous” referred to the sustainable polyester useful in the present invention has the meaning known in the art, i.e. , relating to a polymer which does not have a regular or ordered crystal structure, but having molecular chains randomly and / or disordered arranged, and that, when submitted to Differential Scanning Calorimetry (DSC), does not show a clear and distinct melting peak, but showing a glass transition.

[0065] The term “elastomeric composition” means a composition comprising at least one diene elastomeric polymer and one or more additives, which by mixing and possible heating provides an elastomeric compound suitable for use in tires and components thereof.

[0066] The components of the elastomeric composition are not generally introduced simultaneously into the mixer but typically added in sequence. In particular, the vulcanization additives, such as the vulcanizing agent and possibly the accelerant and retardant agents, are usually added in a downstream step with respect to the incorporation and processing of all the other components.

[0067] In the final vulcanizable elastomeric compound, the individual components of the elastomeric composition may be altered or no longer individually traceable as modified, completely or in part, due to the interaction with the other components, of heat and / or mechanical processing. The term “elastomeric composition” herein is meant to include the set of all the components that are used in the preparation of the elastomeric compound, regardless of whether they are actually present simultaneously, are introduced sequentially or are then traceable in the elastomeric compound or in the final tire.

[0068] The term “elastomeric polymer” indicates a natural or synthetic polymer which, after vulcanization, may be stretched repeatedly at room temperature to at least twice its original length and after removal of the tensile load substantially immediately returns with force to approximately its original length (according to the definitions of the ASTM D1566-11 Standard terminology relating to Rubber).

[0069] The term “diene elastomeric polymer” indicates a polymer or copolymer derived from the polymerization of one or more different monomers, among which at least one of them is a conjugated diene (conjugated diolefin). The term “elastomeric compound” indicates the compound obtainable by mixing and possibly heating at least one elastomeric polymer with at least one of the additives commonly used in the preparation of tire compounds.

[0070] The term “vulcanizable elastomeric compound” indicates the elastomeric compound ready for vulcanization, obtainable by incorporation into an elastomeric compound of all the additives, including those of vulcanization.

[0071] The term “vulcanized elastomeric compound” means the material obtainable by vulcanization of a vulcanisable elastomeric compound.

[0072] The term “green” indicates a material, a compound, a composition, a component or a tire not yet vulcanized.

[0073] The term “vulcanization” refers to the cross-linking reaction in a natural or synthetic rubber induced by a typically sulfur-based cross-linking agent.

[0074] The term “vulcanizing agent” indicates a product capable of transforming natural or synthetic rubber into elastic and resistant material by virtue of the formation of a three-dimensional network of inter- and intra-molecular bonds. Typical vulcanizing agents are sulfur-based compounds such as elemental sulfur, polymeric sulfur, sulfur-donor agents such as bis[(trialkoxysilyl)propyl]polysulphides, thiurams, dithiodimorpholines and caprolactam-disulphide.

[0075] The term “vulcanization accelerant” means a compound capable of decreasing the duration of the vulcanization process and / or the operating temperature, such as sulphenamides, thiazoles, dithiophosphates, dithiocarbamates, guanidines, as well as sulfur donors such as thiurams.

[0076] The term “vulcanization activating agent” indicates a product capable of further facilitating the vulcanization, making it happen in shorter times and possibly at lower temperatures. An example of activating agent is the stearic acid-zinc oxide system.

[0077] The term “vulcanization retardant” indicates a product capable of delaying the onset of the vulcanization reaction and / or suppressing undesired secondary reactions, for example N-(cyclohexylthio)phthalimide (CTP).

[0078] The term “vulcanization package” is meant to indicate the vulcanizing agent and one or more vulcanization additives selected from vulcanization activating agents, accelerants and retardants. The term “reinforcing filler” is meant to refer to a reinforcing material typically used in the sector to improve the mechanical properties of tire rubbers, preferably selected from carbon black, conventional silica, such as silica from sand precipitated with strong acids, preferably amorphous, diatomaceous earth, calcium carbonate, titanium dioxide, talc, alumina, aluminosilicates, kaolin, silicate fibres and mixtures thereof.

[0079] The term “mixing step (1 )” indicates the step of the preparation process of the elastomeric compound in which one or more additives may be incorporated by mixing and possibly heating, except for the vulcanizing agent which is fed in step (2). The mixing step (1 ) is also referred to as “non-productive step”. In the preparation of a compound there may be several “non-productive” mixing steps which may be indicated with 1a, 1 b, etc.

[0080] The term “mixing step (2)” indicates the next step of the preparation process of the elastomeric compound in which the vulcanizing agent and, possibly, the other additives of the vulcanization package are introduced into the elastomeric compound obtained from step (1 ), and mixed in the material, at controlled temperature, generally at a compound temperature lower than 120°C, so as to provide the vulcanisable elastomeric compound. The mixing step (2) is also referred to as “productive step”.

[0081] The term “structural component” of a tire means any layer of elastomeric material of the tire, such as the carcass structure, the belt structure, the pair of sidewalls and the tread band.

[0082] The term “radial carcass structure” indicates a carcass structure comprising a plurality of reinforcing elements, each substantially lying along a respective plane passing through the radius of the tire. Such reinforcing elements may be incorporated in a single carcass ply or in several carcass plies (preferably two) radially superimposed on each other.

[0083] The terms “radial” and “axial” and the expressions “radially internal / external” and “axially internal / external” are used referring respectively to a direction substantially parallel to the equatorial plane of the tire and to a direction substantially perpendicular to the equatorial plane of the tire, i.e. respectively to a direction substantially perpendicular to the axis of rotation of the tire and to a direction substantially parallel to the axis of rotation of the tire.

[0084] The term “crossed belt structure” means a belt structure comprising a first belt layer including reinforcing elements substantially parallel to each other and inclined with respect to the equatorial plane of the tire by a predetermined angle and at least a second belt layer disposed in a radially external position with respect to the first belt layer and including reinforcing elements substantially parallel to each other but lying, with respect to the equatorial plane of the tire, with an inclination opposite to that of the reinforcing elements of the first layer.

[0085] The term “zero-degree belt structure” indicates a reinforcing layer comprising at least one reinforcing element wound on the belt structure according to a substantially circumferential winding direction, i.e. according to a winding direction having an inclination of less than 6° with respect to the equatorial plane of the tire.

[0086] The terms “circumferential” and “circumferentially” are used with reference to the direction of the annular extension of the tire, i.e. to the rolling direction of the tire, which corresponds to a direction lying on a plane coinciding with or substantially parallel to the equatorial plane of the tire.

[0087] By “substantially axial direction” it is meant a direction inclined, with respect to the equatorial plane of the tire, by an angle of between about 70° and about 90°.

[0088] By “substantially circumferential direction” it is meant a direction stretched, with respect to the equatorial plane of the tire, at an angle of between about 0° and about 10°.

[0089] For the purposes of the present description and the following claims, the term “phr” (acronym for parts per hundreds of rubber) indicates the parts by weight of a given elastomeric compound component per 100 parts by weight of the elastomeric polymer, considered net of any extension oils.

[0090] Unless otherwise indicated, all the percentages are expressed as percentages by weight.

[0091] Sustainable polyester

[0092] In an embodiment of the present invention, the sustainable polyester is obtained by the copolymerization of at least one diol and at least one dicarboxylic acid.

[0093] In an embodiment of the present invention, the sustainable polyester is obtained by the copolymerization of at least two diols and at least one dicarboxylic acid. In an embodiment of the present invention, the sustainable polyester is obtained by the copolymerization of at least one diol and at least two dicarboxylic acids.

[0094] In an embodiment of the present invention, the sustainable polyester is obtained by the copolymerization of at least two diols and at least two dicarboxylic acids.

[0095] In an embodiment of the present invention, the sustainable polyester is obtained by the copolymerization of at least one diol, at least one dicarboxylic acid, and at least one hydroxycarboxylic acid.

[0096] In an embodiment of the present invention, the sustainable polyester is obtained by the copolymerization of at least two diols, at least one dicarboxylic acid, and at least one hydroxycarboxylic acid.

[0097] In an embodiment of the present invention, the sustainable polyester is obtained by the copolymerization of at least one diol, at least two dicarboxylic acids, and at least one hydroxycarboxylic acid.

[0098] In an embodiment of the present invention, the sustainable polyester is obtained by the copolymerization of at least two diols, at least two dicarboxylic acids, and at least one hydroxycarboxylic acid.

[0099] In an embodiment of the present invention, the sustainable polyester is obtained by the copolymerization of two diols and three dicarboxylic acids.

[0100] In an embodiment of the present invention, the sustainable polyester is obtained by the copolymerization of two diols, three dicarboxylic acids, and at least one hydroxycarboxylic acid.

[0101] In an embodiment of the present invention, the sustainable polyester comprises a pyrrole ring linked to the alcoholic end of said polyester through an ester bond.

[0102] In an embodiment of the present invention, the sustainable polyester comprises a pyrrole ring linked to the carboxylic end of said polyester through an ester bond.

[0103] In an embodiment of the present invention, the sustainable polyester comprises a pyrrole ring linked to a carbon atom of the diol through an ether or thio bond.

[0104] In an embodiment of the present invention, the sustainable polyester comprises a pyrrole ring linked to a carbon atom of the dicarboxylic acid through an ether or thio bond.

[0105] In an embodiment, the dicarboxylic acid employed to prepare the sustainable polyester of the present invention is selected from the group consisting of 2,5-furandicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, succinic acid, adipic acid, sebacic acid, itaconic acid, and mixture thereof.

[0106] In an embodiment, the diol employed to prepare the sustainable polyester of the present invention is selected from the group consisting of ethylene glycol, 1 ,3-propanediol, 1 ,4 butanediol, and mixture thereof.

[0107] In an embodiment, the hydroxycarboxylic acid employed to prepare the sustainable polyester of the present invention is selected from the group consisting of lactic acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 8- hydroxycaprylic acid, 10-hydroxycapric acid, and cyclic lactones thereof.

[0108] The sustainable polyester of the present invention can be represented by any of the following schematic formulas, wherein the sequence has only to be intended as illustrative without to be limiting to a specific order of the monomers.

[0109] (1 ) Ri-0-[0C-A1 -C0]ai-[0-D1 -0]di-R2

[0110] (2) R2-[0-D1 -0]di-[C0-A1 -CO]ai-[O-D2-O]d2-R2

[0111] (3) Ri-0-[0C-A1 -C0]ai-[0-D1 -O]di-[CO-A2-CO]a2-O-Ri

[0112] (4) Ri-0-[0C-A1 -C0]ai-[0-D1 -O]di-[CO-A2-CO]a2-[O-D2-O]d2-R2

[0113] (5) Ri-0-[0C-A1 -C0]ai-[0-D1 -O]di-[CO-A2-CO]a2-[O-D2-O]d2-[OC-A3-

[0114] C0]a3-0-Rl

[0115] (6) R1-O-[OC-A1 -C0]ai-[0-HA1 -C0]hai-[0-D1-0]di-R2

[0116] (7) R2-[0-D1 -0]di-[C0-A1 -C0]ai-[0-HA1 -CO]hai-[O-D2-O]d2-R2

[0117] (8) Ri-0-[0C-A1 -C0]ai-[0-HA1 -C0]hai-[0-D1 -O]di-[CO-A2-CO]a2-O-Ri

[0118] (9) Ri-0-[0C-A1 -C0]ai-[0-HA1 -C0]hai-[0-D1 -O]di-[CO-A2-CO]a2-[O-D2- O]d2-R2

[0119] (10) R1-O-[OC-A1 -CO]ai-[O-HA1 -CO]hai-[O-D1 -O]di-[CO-A2-CO]a2-[O-D2- O]d2-[OC-A3-CO]a3-O-Ri

[0120] In any one of the above-mentioned formulas (1 ) to (10) the following meaning is applicable, where necessary.

[0121] Any one of A1 , A2, and A3, different from each other, is a residue of a dicarboxylic acid selected from the group consisting of 2,5-furandicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, muconic acid, and 3,3- dithiodipropionic acid.

[0122] Any one of D1 and D2, different from each other, is a residue of a diol selected from the group consisting of ethylene glycol, 1 ,3 propanediol, 1 ,2- propanediol, 1 ,4-butanediol, 1 ,3-butanediol, 1 ,2-butanediol, 2,3-butanediol,

[0123] 1 .5-pentanediol, 1 ,6-hexanediol, cis-1 ,4-butenediol, trans-1 ,4-butenediol, 1 ,8- octanediol, 1 ,10-decanediol, 1 ,12-dodecanediol, 1 ,16-hexadecanediol, and

[0124] 2.5-furandimethanol.

[0125] HA1 is a residue of a hydroxycarboxylic acid selected from the group consisting of lactic acid, glycolic acid, mandelic acid and co-hydroxy acids having four to eighteen carbon atoms.

[0126] Ri is a hydrogen atom or a pyrrole residue having the following formula (I), wherein R4 and R5, equal or different from each other, being hydrogen atom or a C1 -C3 alkyl group, and n being an integer from 1 to 3.

[0127] R2 is a hydrogen atom or a pyrrole residue having the following formula (II), wherein R4 and R5, equal or different from each other, being hydrogen atom or a C1 -C3 alkyl group, and n being an integer from 1 to 3.

[0128] In a preferred embodiment, at least one of A1 , A2, A3, D1 , and D2 comprises a divalent carbon residue having formula -CHR3-, wherein R3 is a hydrogen atom or a pyrrole residue having the following formula (III), wherein R4 and R5, equal or different from each other, are hydrogen atom or a C1-C3 alkyl group, X is oxygen or sulfur atom, n is an integer from 1 to 3, and m is an integer from 0 to 3.

[0129] For sake of greater clarity, it is specified that said bivalent carbon residue having the formula -CHR3- replaces a group -CH2- present in at least one of A1 , A2, A3, D1 and D2, or, in other words, that the group R3 replaces a hydrogen of a group -CH2- present in at least one of A1 , A2, A3, D1 and D2.

[0130] In any one of the above-mentioned formulas (1 ) to (10), the indexes a1 , a2, a3, d1 , d2, and ha1 represent a mole fraction ranging from 0.05 to 0.95 of the respective monomers within the polyester, wherein the sum thereof is always equal to 1 in each of said formula (1 ) to (10).

[0131] In any one of the above-mentioned formulas (1 ) to (10), the sum of the indexes “a”, i.e., a1 or a1 + a2 or a1 + a2 + a3, and, if present, “ha1”, is ranging from 0.40 to 0.60 mole fraction, preferably from 0.50 to 0.60.

[0132] In any one of the above-mentioned formulas (1 ) to (10), the sum of the indexes “d”, i.e., d1 or d1 + d2, is ranging from 0.40 to 0.60 mole fraction, preferably from 0.40 to 0.50.

[0133] In an embodiment of the present invention, the sustainable polyester has a glass transition temperature ranging from -25° to -65°C, more preferably from -30° to -60°C.

[0134] In an embodiment of the present invention, the sustainable polyester has a number average molecular weight (Mn) ranging from 9,000 Da to 50,000 Da, more preferably from 10,000 Da to 40,000 Da

[0135] Diene elastomeric polymer

[0136] The diene elastomeric polymer that is used in the present invention may be selected from those commonly used in sulfur-cross-linkable elastomeric materials, which are particularly suitable for producing tires, i.e. from elastomeric polymers or copolymers with an unsaturated chain characterized by a glass transition temperature (Tg) generally lower than 20°C, preferably in the range of from 0°C to -110°C. These polymers or copolymers may be of natural origin or may be obtained by solution polymerization, emulsion polymerization or gas-phase polymerization of one or more conjugated diolefins, optionally mixed with at least one comonomer selected from monovinylarenes and / or polar comonomers.

[0137] The conjugated diolefins generally contain from 4 to 12, preferably from 4 to 8 carbon atoms and may be selected, for example, from the group comprising: 1 ,3-butadiene, isoprene, 2,3-dimethyl-1 ,3-butadiene, 1 ,3- pentadiene, 1 ,3-hexadiene, 3-butyl-1 ,3-octadiene, 2-phenyl-1 ,3-butadiene or mixtures thereof. 1 ,3-butadiene and isoprene are particularly preferred.

[0138] Monovinylarenes, which may optionally be used as comonomers, generally contain from 8 to 20, preferably from 8 to 12 carbon atoms and may be selected, for example, from: styrene; 1 -vinylnaphthalene; 2-vinylnaphthalene; various alkyl, cycloalkyl, aryl, alkylaryl or arylalkyl derivatives of styrene, such as, for example, a-methylstyrene, 3-methylstyrene, 4-propylstyrene, 4- cyclohexylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4-p-tolyl- styrene, 4-(4-phenylbutyl)styrene, or mixtures thereof. Styrene is particularly preferred.

[0139] Polar comonomers that may optionally be used, can be selected, for example, from: vinylpyridine, vinylquinoline, acrylic acid and alkylacrylic acid esters, nitriles, or mixtures thereof, such as, for example, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, acrylonitrile or mixtures thereof.

[0140] Preferably, the diene elastomeric polymer which can be used in the present invention can be selected, for example, from: cis-1 ,4-polyisoprene (natural or synthetic, preferably natural rubber), 3,4-polyisoprene, polybutadiene (in particular polybutadiene with a high content of 1 ,4-cis), optionally halogenated isoprene / isobutene copolymers, 1 ,3-butadiene / acrylonitrile copolymers, styrene / 1 ,3-butadiene copolymers, styrene / isoprene / 1 ,3-butadiene copolymers, styrene / 1 , 3-butadiene / acrylonitrile copolymers, or mixtures thereof.

[0141] A diene elastomeric polymer functionalized by reaction with suitable terminating agents or coupling agents may also be used. In particular, the diene elastomeric polymers obtained by anionic polymerization in the presence of an organometallic initiator (in particular, an organolithium initiator) may be functionalized by reacting the residual organometallic groups derived from the initiator with suitable terminating agents or coupling agents such as, for example, imines, carbodiimides, alkyltin halides, substituted benzophenones, alkoxysilanes or aryloxysilanes.

[0142] Reinforcing filler

[0143] At least one reinforcing filler may advantageously be added to the elastomeric composition reported above, in an amount generally comprised between 10 phr and 140 phr, preferably between about 12 phr and about 100 phr. The reinforcing filler may be selected from those commonly used for crosslinked products, in particular for tires, such as carbon black, silica, silicates, alumina, aluminosilicates, such as sepiolite, paligorskite also known as attapulgite, montmorillonite, alloisite and the like, possibly modified by acid treatment and / or derivatised., calcium carbonate, kaolin or mixtures thereof. Carbon black, silica and mixtures thereof are particularly preferred.

[0144] According to an embodiment, the carbon black reinforcing filler which may be used in the present invention may be selected from those having a surface area of not less than 20 m2 / g (as determined by STSA - Statistical Thickness Surface Area - according to ISO 18852:2005).

[0145] The silica that may be used in the present invention may generally be a pyrogenic silica or, preferably a precipitated silica, with a BET surface area (measured according to the ISO 5794 / 1 Standard) of between about 50 m2 / g and about 500 m2 / g, preferably between about 70 m2 / g and about 200 m2 / g.

[0146] Examples of silica reinforcing fillers which may be used in the present invention and are commercially available are the products known under the names of Hi-Sil® 190, Hi-Sil® 210, Hi-Sil® 233, Hi-Sil® 243, available from PPG Industries (Pittsburgh, Pa.); or the products known by the names of Ultrasil® VN2, Ultrasil® VN3, Ultrasil® 7000 from Evonik; or the products known by the names of Zeosil® 1165MP and 1115MP from Solvay.

[0147] According to an embodiment, the reinforcing filler is present in the elastomeric composition in an amount greater than about 15 phr, preferably greater than about 20 phr. Preferably, the reinforcing filler is present in the elastomeric composition in an amount of less than about 120 phr, preferably less than about 100 phr.

[0148] According to an embodiment, the elastomeric composition may comprise a silane coupling agent able to interact with the silica possibly present as reinforcing filler and / or the silicates and to bind it to the diene elastomeric polymer during the vulcanization.

[0149] According to an embodiment, the silane coupling agent which may be used in the present invention may be selected from those having at least one hydrolysable silane group, which may be identified, for example, by the following general formula (IV):

[0150] (R)3Si-CnH2n-X (IV) where the R groups, which may be the same or different, are selected from: alkyl, alkoxy or aryloxy groups or from halogen atoms, provided that at least one of the R groups is an alkoxy or aryloxy group; n is an integer of between 1 and 6, inclusive; X is a group selected from: nitrous, mercapto, amino, epoxide, vinyl, imide, chlorine, -(S)mCnH2n-Si-(R)3 and -S-COR, where m and n are integers of between 1 and 6 inclusive and the R groups are as defined above.

[0151] According to an embodiment, said silane coupling agent may be present in the elastomeric composition in an amount ranging between 0.5 phr and about 15 phr, preferably between about 1 phr and about 12 phr.

[0152] Vulcanizing agent

[0153] The elastomeric composition may be vulcanized according to known techniques, in particular with sulfur-based vulcanizing systems commonly used for diene elastomeric polymers. To this end, in the elastomeric compound obtained from the elastomeric composition after one or more thermomechanical treatment steps, a sulfur-based vulcanizing agent is incorporated together with vulcanization accelerants. In the final treatment step, the temperature is generally kept below 120°C and preferably below 100°C, so as to prevent any undesired pre-cross-linking phenomena.

[0154] Preferably, said vulcanizing agent comprises sulfur-based vulcanizing systems comprising sulfur or sulfur-containing molecules (sulfur donors) together with vulcanization accelerants and / or activators known in the art.

[0155] Activators that are particularly effective are zinc compounds, and in particular ZnO, ZnCOs, zinc salts of saturated or unsaturated fatty acids containing from 8 to 18 carbon atoms, such as, for example, zinc stearate, which are preferably formed in situ in the elastomeric composition from ZnO and fatty acid, or mixtures thereof.

[0156] The accelerants which are commonly used may be selected from: dithiocarbamates, guanidine, thiourea, thiazoles, sulphenamides, thiurams, amines, xanthates or mixtures thereof.

[0157] According to a preferred embodiment, said cross-linkable elastomeric composition comprises an amount of vulcanizing agent equal to or greater than about 0,2 phr, preferably equal to or greater than about 0,5 phr.

[0158] Preferably, the amount of vulcanizing agent is less than or equal to about

[0159] 7.5 phr, preferably less than or equal to about 7 phr.

[0160] Advantageously, the amount of sulfur is between about 0,5 phr and about

[0161] 6.5 phr.

[0162] Other additives

[0163] The elastomeric composition according to the present invention may comprise other commonly used additives, selected on the basis of the specific application for which the composition is intended. For example, said materials may be admixed with: antioxidants, anti-ageing agents, plasticisers, adhesives, anti-ozone agents, modifying resins, or mixtures thereof.

[0164] In particular, in order to improve the processability, said vulcanisable elastomeric composition may be admixed with a plasticiser generally selected from mineral oils, vegetable oils, synthetic oils or mixtures thereof, such as, for example, aromatic oil, naphthenic oil, phthalates, soybean oil or mixtures thereof. The amount of plasticiser generally ranges from 0 phr and about 70 phr, preferably from about 5 phr to about 30 phr.

[0165] Preparation of the elastomeric composition

[0166] The elastomeric composition of the present invention comprises at least one diene elastomeric polymer selected from the group of natural and synthetic diene elastomeric polymers, a reinforcing filler, at least one vulcanizing agent, and an amorphous sustainable polyester as described above.

[0167] In an embodiment of the present invention, the elastomeric composition of the present invention comprises an amount of the sustainable polyester ranging from 2% to 25% by weight, with respect the total weight of the vulcanizable elastomeric composition.

[0168] According to a preferred embodiment, the elastomeric composition of the present invention comprises an amount of the sustainable polyester ranging from 3% to 20% by weight, more preferably 5% to 15% by weight, with respect the total weight of the vulcanizable elastomeric composition.

[0169] The elastomeric composition may be prepared by mixing the necessary amount of diene elastomeric polymer with the sustainable polyester, the reinforcing filler, the vulcanizing agent, and any other additives possibly present according to the techniques known in the industry.

[0170] The mixing may be carried out, for example, using at least one batch mixer and / or at least one continuous mixer.

[0171] In the context of the present description and the subsequent claims, the term “batch mixer (or mixing device)” indicates a mixing device configured to be periodically fed with the various ingredients of the material to be prepared in predefined amounts and for mixing them for a predetermined time in order to obtain a batch of said material.

[0172] At the end of the mixing step, the entire batch of material obtained is completely discharged from the mixing device in a single solution. Examples of batch mixers are internal mixers of the type with tangential rotors (Banbury®) or with interpenetrating rotors (Intermix®).

[0173] In the context of the present description and of the subsequent claims, the term “continuous mixer (or mixing device)” indicates a mixing device configured to continuously feed the ingredients of the material to be prepared, typically by means of controlled dosage dispensers, to mix the ingredients in order to produce the material and to discharge it in a continuous flow (except possible stoppages of the mixing device due to maintenance, or change of the recipe of the material).

[0174] In the jargon of the elastomeric mixers sector, the continuous mixing device is sometimes referred to as: “mixing extruder”, which is herein considered equivalent to a “continuous mixer”.

[0175] The continuous mixer (in particular its active elements, such as screws or mixer satellites) is then provided with mixing portions able to impart a high shear stress to the material being mixed and, alternating with the mixing portions, transport portions able to impart a thrust to the material being processed to feed it from one longitudinal end to the other of the inner chamber. It may further be provided with possible redistribution portions. Examples of continuous mixing devices are twin-screw or multi-screw mixers (e.g. ring mixers), co-penetrating and co-rotating, or planetary mixing devices.

[0176] Both the batch mixer and the continuous mixer are able to impart to the material to be produced with them sufficient energy to mix and homogeneously disperse the various components even in the case of cold feeding of the ingredients and, in the case of a material comprising an elastomeric component, to chew the elastomeric compound raising the temperature thereof so as to make it workable and plastic to facilitate the incorporation and / or distribution of the ingredients within the elastomeric polymeric matrix.

[0177] The elastomeric compound thus obtained may then be stored or sent directly to the subsequent production steps of the tire according to the present invention.

[0178] The tire

[0179] According to an embodiment, the tire for vehicle wheels according to the invention comprises:

[0180] - a carcass structure comprising at least a carcass ply having opposite lateral edges associated to respective bead structures;

[0181] - optionally a belt structure applied in radially external position with respect to the carcass structure;

[0182] - a tread band applied in a radially external position to said carcass structure and to said belt structure, if present,

[0183] - a pair of sidewalls applied laterally on the opposite sides with respect to said carcass structure, and

[0184] - optionally, an underlayer and / or an anti-abrasive elongate member and / or a sidewall and / or a sidewall insert and / or a mini-sidewall and / or an underliner and / or a rubberising layer and / or flipper and / or chafer and / or a bead filler and / or a sheet.

[0185] The carcass structure is intended to give the tire the desired features of structural integrity and strength, while the belt structure is also intended to transfer to the carcass structure the lateral and longitudinal stresses to which the running tire is subjected as a result of the contact with the road surface, so as to impart the desired performance of grip, driving stability, controllability, directionality, road grip and comfort.

[0186] The tread band is designed to confer the desired features of dry and wet grip, driving comfort, fuel efficiency, handling and stability, and to maintain such features throughout the life of the tire.

[0187] Preferably, the carcass structure is a radial carcass structure. In an embodiment, the plurality of reinforcing elements is incorporated in two carcass plies radially superimposed on each other.

[0188] Preferably, the belt structure comprises at least one reinforcing element wound on the carcass structure according to a substantially circumferential winding direction.

[0189] Preferably, the tread band is a mono-layer or a two-layer structure. The two- layer structure comprises the rolling layer (called cap) and a substrate (called base) forming the so-called cap-and-base structure.

[0190] A strip consisting of elastomeric compound, commonly known as “minisidewall”, may optionally be provided in the connecting zone the tread band and sidewalls.

[0191] In one embodiment, at least one bead reinforcement layer may be associated with the carcass layer at or in proximity to a respective anchoring structure. Preferably, said at least one bead reinforcement layer comprises at least one reinforcing element. Said at least one bead reinforcement layer may be interposed between a respective turned up end flap of said at least one carcass layer and a respective anchoring structure.

[0192] More preferably, said at least one bead reinforcement layer may at least partially surround said anchoring structure or bead. This bead reinforcement layer is also referred to by the term “flipper”.

[0193] A sidewall reinforcement layer may be associated with the respective turned up end flap of the at least one carcass layer in an axially outermost position with respect to the respective annular anchoring structure.

[0194] More preferably, said at least one sidewall reinforcement layer may extend from said carcass structure along the sidewall towards the tread band. Such sidewall reinforcement layer is also referred to by the term “chafer”.

[0195] In a preferred embodiment, the structural component according to the invention is selected from the group consisting of tread band, either with the mono-layer structure or with the cap-and-base structure, and mini-sidewall.

[0196] The tire according to the invention may be used on two, three or four- wheeled vehicles. The tire according to the invention may be for summer or winter use or for all seasons.

[0197] The tire according to the invention may be a tire for passenger cars, including both automobile tires, such as for example the high-performance tires, and tires for light transport vehicles, for example vans, campers, pick-up, typically with total mass at full load equal to or less than 3500 kg.

[0198] The tire according to the invention may be a tire for motorcycles, such as for example motorcycles belonging to the scooter, road enduro, custom, hypersport, supersport, and sport touring categories. The term “tire for motorcycle wheels” means a tire having a high curvature ratio (typically greater than 0.200), capable of reaching high angles of inclination (roll angles) during cornering of the motorcycle.

[0199] The tire according to the invention may be a tire for bicycle wheels, such as for example for wheels of racing bicycles, off-road bicycles, and city bicycles. Racing bicycles comprise high performance bicycles for road or track competitions, such as, recumbent bicycles, time trial bicycles, triathlon bicycles, and / or so-called fitness bikes. Off-road bicycles comprise bicycles for uneven or irregular terrain, such as muddy, sandy, rocky, compact, soft ground, and so on, and include in particular mountain bikes (MTB) or all terrain bikes (ATB), conventionally divided into the Cross Country (XC), Marathon, Trail, All Mountain, Enduro, Freeride, and Downhill categories. City bicycles comprise bicycles for urban use on mainly asphalted road or cycleways, such as urban bikes, city bikes, trekking bikes and touring bikes.

[0200] DRAWINGS

[0201] The description is given hereinafter with reference to the accompanying drawings, provided only for illustrative and, therefore, non-limiting purposes, in which:

[0202] - Figure 1 schematically shows a semi-sectional view of a tire for vehicle wheels according to the present invention;

[0203] - Figure 2 shows the1H-NMR spectra of 2-(2,5-dimethyl-1 H-pyrrol-1 -yl) ethan-1-ol dissolved in DMSO-de and collected with 400 MHz Broker spectrometer; - Figure 3 shows the1H-NMR spectra of Polymer 2 dissolved in DMSO- de and collected with 400 MHz Broker spectrometer;

[0204] - Figure 4 shows the1H-NMR spectra of Polymer 3 dissolved in DMSO- de and collected with 400 MHz Broker spectrometer;

[0205] - Figure 5 shows the1H-NMR spectra of Polymer 5 dissolved in DMSO- de and collected with 400 MHz Broker spectrometer;

[0206] - Figure 6 shows the1H-NMR spectra of Polymer 7 dissolved in DMSO- de and collected with 400 MHz Broker spectrometer;

[0207] - Figure 7 shows the1H-NMR spectra of Polymer 8 dissolved in DMSO- de and collected with 400 MHz Broker spectrometer;

[0208] - Figure 8 shows the DSC thermogram of Polymer 1 , 3, 5 and 7;

[0209] - Figure 9 shows the DSC thermogram of Polymer 4 and Polymer 8;

[0210] DETAILED DESCRIPTION OF THE INVENTION

[0211] The present invention will be illustrated in further detail by means of an illustrative embodiment with reference to the accompanying Figure 1 , where “a” indicates an axial direction and “r” indicates a radial direction. For simplicity, Figure 1 shows only a part of the tire, the remaining part not shown being identical and disposed symmetrically with respect to the radial direction “r”.

[0212] The reference numeral 100 indicates in Figure 1 a tire for vehicle wheels, which generally comprises a carcass structure 101 having respectively opposite end flaps engaged with respective annular anchoring structures 102, called bead cores, possibly associated with a bead filler 104. The tire area comprising the bead core 102 and the filler 104 forms a bead structure 103 intended for anchoring the tire onto a corresponding mounting rim, not shown. Each bead structure 103 is associated to the carcass structure by folding back of the opposite lateral edges of the at least one carcass layer 101 around the bead core 102 so as to form the so-called carcass flaps 101 a as shown in Figure 1 .

[0213] The carcass structure 101 is possibly associated with a belt structure 106 comprising one or more belt layers 106a, 106b placed in radial superposition with respect to one another and with respect to the carcass structure 101 , having typically metal reinforcing cords. Such reinforcing cords may have crossed orientation with respect to a circumferential extension direction of the tire 100. By “circumferential” direction we mean a direction generally facing according to the direction of rotation of the tire, or in any case slightly inclined with respect to the direction of rotation of the tire.

[0214] The belt structure 106 further comprises at least one radially external reinforcing layer 106c with respect to the belt layers 106a, 106b. The radially external reinforcing layer 106c comprises textile or metal cords, disposed according to a substantially zero angle with respect to the circumferential extension direction of the tire and immersed in the elastomeric material. Preferably, the cords are disposed substantially parallel and side by side to form a plurality of turns. Such turns are substantially oriented according to the circumferential direction (typically with an angle of between 0° and 5°), such direction being usually called “zero degrees” with reference to the laying thereof with respect to the equatorial plane X-X of the tire. By “equatorial plane” of the tire it is meant a plane perpendicular to the axis of rotation of the tire and which divides the tire into two symmetrically equal parts.

[0215] A tread band 109 of a vulcanized elastomeric compound is applied in a radially external position with respect to the carcass structure 101 and / or if present (as in the illustrated case) to the belt structure 106.

[0216] In a radially external position, the tread band 109 has a rolling portion 109a intended to come into contact with the ground. Circumferential grooves, which are connected by transverse notches (not shown in Figure 1 ) so as to define a plurality of blocks of various shapes and sizes distributed in the rolling portion 109a, are generally made in this portion 109a, which for simplicity is represented smooth in Figure 1 .

[0217] To optimise the performance of the tread, the tread band may be made in a two-layer structure.

[0218] Such two-layer structure comprises the rolling layer or portion 109a (called cap) and a substrate 111 (called base) forming the so-called cap-and-base structure. It is thus possible to use an elastomeric material capable of providing a low rolling resistance for the cap 109a and at the same time high resistance to wear and to the formation of cracks while the elastomeric material of the substrate 111 may be particularly aimed at a low hysteresis to cooperate in reducing rolling resistance. The under-layer 111 of vulcanized elastomeric compound may be disposed between the belt structure 106 and the rolling portion 109a. Moreover, respective sidewalls 108 of vulcanized elastomeric compound are further applied in an axially external position to said carcass structure 101 , each extending from one of the lateral edges of the tread band 109 up to the respective bead structure 103.

[0219] A strip consisting of elastomeric compound 110, commonly known as “minisidewall”, of vulcanized elastomeric compound may optionally be provided in the connecting zone between sidewalls 108 and the tread band 109, this minisidewall generally being obtained by co-extrusion with the tread band 109 and allowing an improvement of the mechanical interaction between the tread band 109 and the sidewalls 108. Preferably, the end portion of sidewall 108 directly covers the lateral edge of the tread band 109.

[0220] In some specific embodiments, such as the one illustrated and described herein, the stiffness of the bead 103 may be improved by providing a reinforcing layer 120 generally known as a “flipper” in the tire bead.

[0221] The flipper 120 is wrapped around the respective bead core 102 and the bead filler 104 so as to at least partially surround them. The flipper 120 is disposed between the carcass layer 101 and the bead structure 103. Usually, the flipper 120 is in contact with the carcass layer 101 and said bead structure 103. The flipper 120 typically comprises a plurality of metal or textile cords incorporated in a vulcanized elastomeric compound.

[0222] In some specific embodiments, such as the one illustrated and described herein, the bead structure 103 may further comprise a further reinforcing layer 121 which is generally known by the term of “chafer” and which has the function to increase the rigidity and integrity of the bead structure 103.

[0223] The chafer 121 usually comprises a plurality of cords incorporated in a vulcanized elastomeric compound; such cords are generally made of textile material (for example aramid or rayon), or of metallic material (for example steel cords).

[0224] Optionally, an anti-abrasive strip 105 is disposed so as to wrap the bead structure 103 along the axially internal and external and radially internal areas of the bead structure 103, thus interposing itself between the latter and the wheel rim when the tire 100 is mounted on the rim.

[0225] Moreover, a radially internal surface of tire 100 is preferably internally lined by a layer of substantially airtight elastomeric material, or so-called liner 112. According to an embodiment not shown, the tire may be a tire for motorcycle wheels. The profile of the straight section of the tire for motorcycle (not shown) has a high transversal curvature since it must guarantee a sufficient footprint area in all the inclination conditions of the motorcycle. The transverse curvature is defined by the value of the ratio between the distance f of the ridge of the tread from the line passing through the laterally opposite ends of the tread itself, measured on the equatorial plane of the tire, and the width C defined by the distance between the laterally opposite ends of the tread itself. A tire with high transverse curvature indicates a tire whose transverse curvature ratio (f / C) is at least 0.20.

[0226] Any of the above elastomeric elements of the tire may be advantageously made with the elastomeric composition comprising the sustainable polyester according to the present invention, preferably the tread band 109, and / or the cap 109a, and / or the base 111 and / or the mini-sidewall 110.

[0227] The building of the tire 100 as described above is carried out by assembling respective semi-finished products onto a forming drum, not shown, by at least one assembly device.

[0228] At least a part of the components intended to form the carcass structure 101 of the tire 100 is built and / or assembled on the forming drum. More particularly, the forming drum is intended to first receive the possible liner 112, and then the carcass ply 101. Thereafter, devices non shown coaxially engage one of the annular anchoring structures 102 around each of the end flaps, position an external sleeve comprising the belt structure 106 and the tread band 109 in a coaxially centred position around the cylindrical carcass sleeve and shape the carcass sleeve according to a toroidal configuration through a radial expansion of the carcass ply 101 , so as to cause the application thereof against a radially internal surface of the external sleeve.

[0229] After building of the green tire 100, a molding and vulcanization treatment is generally carried out in order to determine the structural stabilization of the tire 100 through vulcanization of the elastomeric compounds, as well as to impart a desired tread pattern on the tread band 109 and to impart any distinguishing graphic signs at the sidewalls 108.

[0230] The present invention will be further illustrated below by means of a number of preparatory examples, which are provided for indicative purposes only and without any limitation of the present invention. EXAMPLES

[0231] Characterization methods

[0232] 1H-NMR analysis

[0233] Microstructure composition of samples was determined by dissolving 10 ± 1 mg into 1 .5 mL of d6-dmso solvent, and 0.75 mL of the solution obtained was transferred to an NMR test tube and analyzed with 400 MHz Bruker nuclear magnetic resonance spectrometer.

[0234] Differential scanning calorimetry

[0235] Differential scanning calorimetry (DSC) analysis was performed on polymer sample of 10 ± 1 mg.

[0236] Heating / cooling cycles consisted in a first thermal scansion from 25°C to 120°C to cancel the thermal history of the sample, then sample was cooled from 120°C to -70°C and subsequently heated from -70°C to 120°C. Heating / cooling rate adopted in all the cycles was 10°C / min. Thermal transitions were determined in the second heating cycle.

[0237] Gel Permeation Chromatography

[0238] Molecular weight distribution of the polymer was determined GPC-MALS on 3.0 ± 0.1 mg polymer sample of dissolved in in 1 mL of tetrahydrofuran (THF) as solvent.

[0239] The molecular weights were detected with a triple detector consisting in light scattering, refractive index, and viscosity detection.

[0240] Using the GPC-MALS technique, which combines a light scattering detector with a refractive index detector, it is possible to perform an absolute measurement of molecular weight without the need to create a calibration curve using standard polymer samples of known molecular weight.

[0241] The molecular weights of the samples were measured using a triple detector system manufactured by Wyatt Technology Corporation, consisting of a miniDAWN® TREOS multi-angle light scattering detector, an Optilab® T-rEX Refractive Index Detector and a ViscoStar® II Viscometer.

[0242] The HPLC column bench used consists of three Tosoh columns of the TSKgel® G1000HHR, G2000HHR, and G2500HHR types.

[0243] The measurement is carried out under thermal equilibrium conditions, conditioning the system for at least 12 hours at 30°C with a flow of 1 ml / min of THF.

[0244] MDR rheometric analysis

[0245] MDR rheometric analysis was performed by using a rheometer Monsanto R.P.A. 2000 using the following procedure: 5.0 g of green compound were charged into the RPA at 50°C for 1 minute and the first strain-sweep test was conducted (low deformations, 0.1 -25% strain) at 50°C. The sample was then cross-linked at 170°C for 10’ at 1.7 Hz of frequency and with an oscillation angle of 6.98% (0.5 rad).

[0246] The following parameters were obtained: Minimum torque (M L), Maximum torque (MH), induction time (tsi) and times to achieve the optimum level of vulcanization (too), curing rate. The curing rate was calculated by using the following equation:

[0247] Dynamic-mechanical analysis in the shear mode. Strain sweep test

[0248] The storage G’ modulus, the loss G” modulus and Tan Delta were determined by using a rheometer Monsanto R.P.A. 2000 using the following procedure: 5.0 g of green compound were charged into the RPA at 50°C for 1 minute and the first strain-sweep test was conducted (low deformations, 0.1 - 25% strain) at 50°C. The sample was then cross-linked at 170°C for 10’ at 1 .7 Hz of frequency and with an oscillation angle of 6.98% (0.5 rad). After vulcanization, the sample was kept at 50°C for 20 minutes. The final values of G’, G” and Tan Delta were obtained with a strain sweep test at low deformations (0.1 - 25% strain) at 50°C and with 1 Hz frequency.

[0249] Dynamic-mechanical analysis in the axial mode.

[0250] The dynamic-mechanical properties in the axial mode, the storage E’ modulus, the loss E” modulus and Tan Delta were measured using an Instron dynamic device in the traction-compression mode according to the following methods. The crosslinked elastomers with a cylindrical form (length= 25mm; diameter = 12 mm) were kept at the prefixed temperature of 10°C, 23°C and 70° C for the whole duration of the test. The samples were initially precompressed up to a 25% longitudinal deformation with respect to the initial length and then submitted to a dynamic sinusoidal strain with an amplitude of ± 3.5% with respect to the original length. The frequency used was 100 Hz. The measured properties were dynamic storage modulus (E’), dynamic loss modulus (E”) and consequently tan delta (loss factor) through the ratio of the two moduli (E” / E’). Each modulus was plotted against temperature for the frequency used (100 Hz) to observe the effect of temperature on the dynamic mechanical properties in each sample.

[0251] Tensile test

[0252] Tensile strength test was carried out according to ISO 37 standard at 23°C for each sample, using Zwick Roell Z010. Tensile testing is a destructive test process that provides information about the tensile strength, yield strength, and ductility of the material. It measures the force required to break a specimen and the extent to which the specimen stretches or elongates to that breaking point. Tensile measurements were determined on samples of the elastomeric compounds vulcanized at 170°C for 10 minutes. Three replicates of each rubber compound were prepared and tested.

[0253] The stress at 50% (Ca0.5), 100% (Ca1 ), and 300% elongation (Ca3), together with stress at break (CR) and elongation at break (AR) were evaluated through this test, as average values of the 3 replicates.

[0254] Synthesis of the pyrrole derivative

[0255] In a single-necked round bottom flask equipped with reflux condenser, ethanolamine (35,9 mmol, 2.19 g) was added and heated at 140 °C under magnetic stirring. After 5 minutes, 2,5 hexandione (35,9 mmol, 4,10 g) was added dropwise. The reaction mixture was left under stirring for 2,5 hours.

[0256] After that, the reflux condenser was removed, and the reaction was left under stirring at 145°C for other 30 minutes. A dark yellow solid product was obtained.

[0257] The following scheme gives a schematic representation of the abovedescribed synthesis giving the 2-(2,5-dimethyl-1 H-pyrrol-1 -yl) ethan-1-ol product.

[0258] The1H-NMR spectra of 2-(2,5-dimethyl-1 H-pyrrol-1 -yl) ethan-1-ol dissolved in DMSO-de and collected with 400 MHz Broker spectrometer is illustrated in Figure 2.

[0259] Synthesis of the sustainable polyesters

[0260] Synthesis of Polymer 1

[0261] In a three neck round bottom flask equipped with Claisen condenser linked to the vacuum line, mechanical stirrer, and nitrogen inlet, were added in sequence itaconic acid (45.20 mmol 5.88 g), 1 ,3 propanediol (175.02 mmol, 13.32 g), 1 .4 butanediol (165.77 mmol, 14.94 g), succinic acid (129.14 mmol, 15.25 g), sebacic acid (127.33 mmol, 25.75 g), hydroquinone (0.33 mmol, 36 mg) and orthophosphoric acid (0.25 mmol, 24 mg). The mixture was heated at 180°C under nitrogen atmosphere and stirred at 400 rpm for three hours.

[0262] After that, tetrabutyl titanate (0.14 mmol, 49 mg) was added to the mixture at 180°C always maintaining the nitrogen atmosphere, and then the temperature was gradually raised up to 210°C over 4 hours with the pressure reduced to 30 kPa. The copolyester obtained was cooled down to room temperature and washed three times with ethanol. The polymer was filtered and dried under vacuum at 40°C until constant weight.

[0263] The number average molecular weight of the polyester was 24,560 and the weight average molecular weight was 39,050, the polydispersity coefficient is 1.59.

[0264] The following scheme gives a schematic representation of the synthesis of poly(propylene-co-butylene) itaconate-co-sebacate-co-succinate (Polymer 1 ). Here and in all similar schemes the sequence of monomers is purely illustrative.

[0265] The glass transition temperature (Tg) of Polymer 1 resulting from DSC analysis was -46.4°C. The DSC thermogram of Polymer 1 is illustrated in Figure 8. Synthesis of Polymer 2

[0266] In a three neck round bottom flask equipped with Claisen condenser linked to the vacuum line, mechanical stirrer, and nitrogen inlet, were added in sequence itaconic acid (30.26 mmol 3.94 g), 1 ,3 propanediol (84.24 mmol, 6.41 g), 1.4 butanediol (82.95 mmol, 7.48 g), succinic acid (63.86 mmol, 7.54 g), sebacic acid (63.80 mmol, 12.90 g), hydroquinone (0.21 mmol, 23 mg) and orthophosphoric acid (0.87 mmol, 85 mg). The mixture was heated at 180°C under nitrogen atmosphere and stirred at 400 rpm for three hours.

[0267] After that, tetrabutyl titanate (0.13 mmol, 45 mg) was added to the mixture at 180°C always maintaining the nitrogen atmosphere, and then the temperature was gradually raised up to 210°C over 4 hours with the pressure reduced to 30 kPa.

[0268] The copolyester obtained was cooled down to room temperature and washed three times with ethanol. The polymer was filtered and dried under vacuum at 40°C until constant weight.

[0269] The number average molecular weight of the polyester was 10,860 and the weight average molecular weight was 18,860, the polydispersity coefficient is 1.74.

[0270] The following scheme gives a schematic representation of the synthesis of poly(propylene-co-butylene) itaconate-co-sebacate-co-succinate (Polymer 1 ). The1H-NMR spectra of Polymer 2 dissolved in DMSO-de and collected with

[0271] 400 MHz Broker spectrometer is illustrated in Figure 3. The glass transition temperature (Tg) of Polymer 2 resulting from DSC analysis was -50.2°C.

[0272] Synthesis of Polymer 3 In a three neck round bottom flask equipped with Claisen condenser linked to the vacuum line, mechanical stirrer, and nitrogen inlet, were added in sequence 2.5 furandicarboxylic acid (35.7 mmol 5.57 g), ethylene glycol (112.12 mmol, 6.96 g), 1 ,3 propanediol (110.71 mmol, 8.424 g), hydroquinone (0.42 mmol, 46 mg) and orthophosphoric acid (0.42 mmol, 41 mg). The mixture was heated at 180°C under nitrogen atmosphere and stirred at 400 rpm for one hour. Then, succinic acid (85.00 mmol, 10.04 g) and sebacic acid (80.00 mmol, 16.18 g) were added to the mixture at 180 °C always maintaining the nitrogen atmosphere. The mixture was stirred at 180°C under nitrogen atmosphere for two additional hours. After that, tetrabutyl titanate (0.14 mmol, 46 mg) was added to the mixture at 180°C always maintaining the nitrogen atmosphere, and then the temperature was gradually raised up to 220°C over 4 hours with the pressure reduced to 30 kPa.

[0273] The copolyester obtained was cooled down to room temperature and washed three times with ethanol. The polymer was filtered and dried under vacuum at 40°C until constant weight.

[0274] The number average molecular weight of the polyester was 20, 170 and the weight average molecular weight was 45,770, the polydispersity coefficient is 2.27. The following scheme gives a schematic representation of the synthesis of poly(ethylene-co-propylene) furanoate-co-sebacate-co-succinate (Polymer 4).

[0275] The1H-NMR spectra of Polymer 3 dissolved in DMSO-de and collected with 400 MHz Broker spectrometer is illustrated in Figure 4. The glass transition temperature (Tg) of Polymer 3 resulting from DSC analysis was -36.6°C. The DSC thermogram of Polymer 3 is illustrated in Figure 8.

[0276] Synthesis of Polymer 4

[0277] In a three neck round bottom flask equipped with Claisen condenser linked to the vacuum line, mechanical stirrer, and nitrogen inlet, were added in sequence 2.5 furandicarboxylic acid (30.39 mmol 4.74 g), ethylene glycol (206.36 mmol, 12.81 g), hydroquinone (0.57 mmol, 63 mg) and orthophosphoric acid (0.82 mmol, 81 mg). The mixture was heated at 180°C under nitrogen atmosphere and stirred at 400 rpm for one hour. Then, 1 ,3 propanediol (28.9 mmol, 2.20 g), succinic acid (85.00 mmol, 10.04 g) and sebacic acid (85.00 mmol, 17.19 g) were added to the mixture at 180 °C always maintaining the nitrogen atmosphere. The mixture was stirred at 180°C under nitrogen atmosphere for two additional hours.

[0278] After that, tetrabutyl titanate (0.14 mmol, 46 mg) was added to the mixture at 180 °C always maintaining the nitrogen atmosphere, and then the temperature was gradually raised up to 220°C over 4 hours with the pressure reduced to 30 kPa.

[0279] The copolyester obtained was cooled down to room temperature and washed three times with ethanol. The polymer was filtered and dried under vacuum at 40°C until constant weight. The number average molecular weight of the polyester was 12,580 and the weight average molecular weight was 15,810, the polydispersity coefficient is 1.26.

[0280] The following scheme gives a schematic representation of the synthesis of poly(ethylene-co-propylene) furanoate-co-sebacate-co-succinate (Polymer 4).

[0281] The glass transition temperature (Tg) of Polymer 4 resulting from DSC analysis was -30.8°C. The DSC thermogram of Polymer 4 is illustrated in Figure 9. Synthesis of Polymer 5

[0282] In a three neck round bottom flask equipped with Claisen condenser linked to the vacuum line, mechanical stirrer, and nitrogen inlet, were added in sequence bis-(2-hydroxyethyl) terephthalate (8.65 g, 34.00 mmol), sebacic acid (20.23g, 100.03 mmol), succinic acid (11.81 g, 100.02 mmol), hydroquinone (0.57 mmol, 63 mg) and orthophosphoric acid (0.82 mmol, 81 mg). The mixture was heated at 180°C under nitrogen atmosphere and stirred at 400 rpm for one hour.

[0283] Then, ethylene glycol (5.34 g, 85.99 mmol) and 1 ,3-propanediol (7.62 g, 100.11 mmol) were added to the mixture at 180 °C always maintaining the nitrogen atmosphere. The mixture was stirred at 180°C under nitrogen atmosphere for two additional hours. After that, tetrabutyl titanate (0.14 mmol, 46 mg) was added to the mixture at 180 °C always maintaining the nitrogen atmosphere, and then the temperature was gradually raised up to 220°C over 4 hours with the pressure reduced to 30 kPa.

[0284] The copolyester obtained was cooled down to room temperature and washed three times with ethanol. The polymer was filtered and dried under vacuum at 40°C until constant weight.

[0285] The number average molecular weight of the polyester was 10,080 and the weight average molecular weight was 11 ,460, the polydispersity coefficient is 1.14.

[0286] The1H-NMR spectra of Polymer 5 dissolved in DMSO-de and collected with 400 MHz Broker spectrometer is illustrated in Figure 5. The glass transition temperature (Tg) of Polymer 5 resulting from DSC analysis was -38.2°C. The DSC thermogram of Polymer 5 is illustrated in Figure 8.

[0287] Synthesis of Polymer 6

[0288] In a three neck round bottom flask equipped with Claisen condenser linked to the vacuum line, mechanical stirrer, and nitrogen inlet, were added in sequence adipic acid (15.01 mmol 2.19 g), 1 ,3 propanediol (48.31 mmol, 3.68 g), 1.4 butanediol (48.70 mmol, 4.39 g), succinic acid (42.58 mmol, 5.03 g), sebacic acid (42.52 mmol, 8.60 g), hydroquinone (0.21 mmol, 23 mg) and orthophosphoric acid (0.21 mmol, 21 mg). The mixture was heated at 180°C under nitrogen atmosphere and stirred at 400 rpm for three hours.

[0289] After that, tetrabutyl titanate (0.13 mmol, 45 mg) was added to the mixture at 180°C always maintaining the nitrogen atmosphere, and then the temperature was gradually raised up to 220°C over 4 hours with the pressure reduced to 30 kPa.

[0290] The copolyester obtained was cooled down to room temperature and washed three times with ethanol. The polymer was filtered and dried under vacuum at 40°C until constant weight.

[0291] The number average molecular weight of the polyester was 10, 160 and the weight average molecular weight was 12,293, the polydispersity coefficient is 1.21. The glass transition temperature (Tg) of Polymer 6 resulting from DSC analysis was -54.1 °C.

[0292] Synthesis of Polymer 7

[0293] In a three neck round bottom flask equipped with Claisen condenser linked to the vacuum line, mechanical stirrer, and nitrogen inlet, were added in sequence adipic acid (49.45 mmol 7.23 g), 1 ,3 propanediol (115.35 mmol, 8.78 g), 1.4 butanediol (66.48 mmol, 5.99 g), succinic acid (82.51 mmol, 9.74 g), sebacic acid (33.08 mmol, 6.69 g), and hydroquinone (0.18 mmol, 20 mg). The mixture was heated at 180°C under nitrogen atmosphere and stirred at 400 rpm for three hours.

[0294] After that, tetrabutyl titanate (0.13 mmol, 45 mg) was added to the mixture at 180°C always maintaining the nitrogen atmosphere, and then the temperature was gradually raised up to 220°C over 4 hours with the pressure reduced to 30 kPa.

[0295] The copolyester obtained was cooled down to room temperature and washed three times with ethanol. The polymer was filtered and dried under vacuum at 40°C until constant weight.

[0296] The number average molecular weight of the polyester was 32050 and the weight average molecular weight was 48350, the polydispersity coefficient is 1.51.

[0297] The1H-NMR spectra of Polymer 7 dissolved in DMSO-de and collected with 400 MHz Broker spectrometer is illustrated in Figure 6. The glass transition temperature (Tg) of Polymer 7 resulting from DSC analysis was -52.1 °C. The DSC thermogram of Polymer 7 is illustrated in Figure 8.

[0298] Synthesis of Polymer 8

[0299] In a three neck round bottom flask equipped with Claisen condenser linked to the vacuum line, mechanical stirrer, and nitrogen inlet, were added in sequence adipic acid (49.45 mmol 7.23 g), 1 ,3 propanediol (115.35 mmol, 8.78 g), 1.4 butanediol (66.49 mmol, 5.99 g), succinic acid (82.51 mmol, 9.74 g), sebacic acid (33.08 mmol, 6.69 g) and hydroquinone (0.18 mmol, 20 mg). The mixture was heated at 180°C under nitrogen atmosphere and stirred at 400 rpm for three hours.

[0300] After that, tetrabutyl titanate (0.13 mmol, 45 mg) was added to the mixture at 180°C always maintaining the nitrogen atmosphere, and then the temperature was gradually raised up to 220°C over 4 hours with the pressure reduced to 30 kPa.

[0301] The copolyester obtained was cooled down to room temperature and washed three times with ethanol. The polymer was filtered and dried under vacuum at 40°C until constant weight.

[0302] After that, 2-(2,5-dimethyl-1 H-pyrrol-1 -yl)ethan-1 -ol (6.99 mmol, 0.97 g) and tetrabutyl titanate (0.07 mmol, 25 mg) were added to the copolyester and the mixture was heated at 100°C under reduced pressure for two hours.

[0303] The product obtained was cooled down to room temperature and washed three times with a solution water / ethanol (3:7 v / v). The polymer was filtered and dried under vacuum at 40°C until constant weight. The number average molecular weight of the polyester was 57,550 and the weight average molecular weight was 82,730, the polydispersity coefficient is 1.44.

[0304] The following scheme gives a schematic representation of the synthesis of poly(propylene-co-butylene) adipate-co-sebacate-co-succinate terminated with ethanol pyrrole (Polymer 8).

[0305] The1H-NMR spectra of Polymer 8 dissolved in DMSO-de and collected with 400 MHz Broker spectrometer is illustrated in Figure 7. The glass transition temperature (Tg) of Polymer 8 resulting from DSC analysis was -50.1 °C. The DSC thermogram of Polymer 8 is illustrated in Figure 9.

[0306] Preparation of rubber compounds Example 1

[0307] A masterbatch was prepared in a first step including styrene-butadiene rubber, natural rubber, 2 / 3 of the total amount of silica, silane and stearic acid.

[0308] The recipes of the elastomeric compounds are reported in the following Table 1.1. The amounts are expressed in phr. The amounts in parenthesis are expressed in percent by weight with respect to the total weight of the compositions.

[0309] In the second step the masterbatch was first introduced in the internal mixer, Brabender® type, and mixed for 2 minutes at 150°C. Then, the remaining amount (1 / 3) of silica impregnated with conventional oils or sustainable polymers was added at 150°C and mixed for 3 minutes.

[0310] The obtained compound was discharged, and the internal mixer temperature lowered to 70°C. At this temperature, in the third step the compound was reloaded and mixed for 1 minute. Then, zinc oxide and 6PPD were added and mixed for another minute. After that, TBBS and Sulphur were added and mixed for 1 minutes at 70 °C. At the end of the mixing, the elastomeric composite was unloaded.

[0311] TABLE 1.1

[0312] SBR1 styrene-butadiene rubber partially coupled to Si, comprising 25% by weight of styrene and 63% by weight of vinyl with respect to the butadiene content, produced by anionic polymerisation in solution using an organo-lithium initiator; extended with 37.5 parts of TDAE oil for every 100 parts of dry polymer (SPRINTAN™ SLR 4630; Trinseo)

[0313] SBR2 functionalized styrene butadiene copolymer - microstructure with 21 % styrene and 62.5% vinyl on the butadiene fraction (SPRINTAN™ SLR 4602; Trinseo)

[0314] NR natural rubber (Standard Thai Rubber STR 20 - Thaiteck Rubber);

[0315] Silica Zeosil® 1165 MP, standard grade with surface area of approx. 175 m2 / g from

[0316] Solvay;

[0317] Silane TESPT, bis[3-(triethoxysilyl)propyl]tetrasulphide JH-S69 from ChemSpec Ltd.;

[0318] Oil1 T-DAE (treated distilled aromatic extract), Vivatec 500 (H & R Group, Hamburg, Germany)

[0319] Oil2 low molecular weight (Mn 4500) liquid styrene butadiene copolymer, 25% styrene (Ricon 100®, Cray Valley)

[0320] 6PPD N-(1 ,3-dimethylbutyl)-N’-phenyl-p-phenylene-diamine SANTOFLEX 6PPD from EASTMAN

[0321] ZnO Standard Zn oxide from A-Esse

[0322] TBBS N-tert-butyl-2-benzothiazole sulfonamide, (Lanxess Deutschland GmbH, Germany)

[0323] Sulfur Sulphur 98.50% (1% oil) - Zolfindustria

[0324] The resulting elastomeric compounds were tested according to the abovedescribed procedures. The results are summarized below. Results

[0325] The results of MDR rheometric analysis are reported in the following Table 1.2. TABLE 1.2

[0326] The compounds containing the sustainable polymers of the present invention (11 and I2) show ML value higher than the ML of reference compounds (R1 and R2), containing the T-DAE oil and the low molecular weight SBR respectively. However, all the ML values are in a narrow range. The ML value is an index of compound viscosity. Hence, all the compounds have similar viscosities, could be processed with the same equipment, and could have similar processing behavior. This is indeed a relevant result, as T-DAE is an oil and the low molecular weight SBR does not have any specific interaction with the filler, so that both are ingredients expected to lead to the reduction of the viscosity of the composite. On the contrary, the polyesters are expected to have a pronounced interaction with the filler, and this could have led to a remarkable enhancement of the viscosity, that was not observed.

[0327] The compounds containing the sustainable polymers of the present invention (11 and I2) showed MH value (and MH - ML values) higher than the MH (and MH - ML values) of reference compounds (R1 and R2) containing the T-DAE oil and the low molecular weight SBR respectively. The MH value is correlated with the crosslinking network but also with the filler network, as the extent of the strain adopted during curing is not enough to completely disrupt the filler network. However, the much higher value of MH-ML allows to comment that the compounds of the present invention (11 and I2) containing the polyesters (Polymer 2 and Polymer 4) have a higher crosslinking degree.

[0328] The compounds containing the polyesters (Polymer 2 and 4) lead to appreciably higher curing rate. In conclusion, the compounds of the present invention (11 and I2) have remarkably higher crosslinking efficiency.

[0329] The results of dynamic-mechanical analysis in the shear mode are reported in the following Table 1 .3. TABLE 1.3

[0330] The compounds containing the sustainable polymers of the present invention (11 and I2) showed G'Y=o.4% and G'Y=25% values higher than the G' Y=O.4% and G'Y=25% values of reference compounds (R1 and R2) containing the T-DAE oil and the low molecular weight SBR respectively.

[0331] The AG' I G'Y=o.4% value for the compounds containing the sustainable polymers of the present invention (11 and I2) is slightly higher than the AG' I G' Y=O.4% value of the reference compound (R1 and R2).

[0332] However, the Tan delta max values appear to be in a narrow range for all the compounds and the compounds containing the sustainable polymers of the present invention did not show the highest value.

[0333] The results of dynamic-mechanical analysis in the axial mode are reported in the following Table 1 .4.

[0334] TABLE 1.4

[0335] The compounds containing the sustainable polymers of the present invention (11 and I2) showed E’ values remarkably higher than the E’ values of the reference compounds (R1 and R2), containing the T-DAE oil and the low molecular weight SBR respectively. Hence, the polyesters lead to the highest dynamic rigidity.

[0336] The compounds of the present invention (11 and I2) showed tan delta values between 10°C and 70°C substantially in line with the tan delta values of the compound R1 with T-DAE. The polyesters appeared as ingredients suitable to reduce the hysteresis of a silica-based compound. In fact, the higher dynamic rigidity (E’ values) of the compounds of the present invention (11 and I2) would allow to reduce the amount of filler, hence the tan delta of the compounds.

[0337] The results of tensile test are reported in the following Table 1 .5.

[0338] TABLE 1.5

[0339] With respect to the reference compound (R1 ) with T-DAE, the compound of the present invention containing polymer 4 (I2) showed stresses at the different elongations and at break, which was substantially in line, whereas the compound of the present invention containing polymer 2 (11 ) showed values somewhat lower, however substantially similar.

[0340] With respect to the reference compound (R2) with the low molecular weight SBR, the compounds of the present inventions (11 and I2) showed higher values of stresses at 100% and 300% strain and lower ultimate properties, confirming that the polymers of the invention, although of relatively low MW, do not behave in compound like standard low molecular weight dienic polymers.

[0341] The overall results of axial dynamic mechanical and tensile measurements demonstrated that the compounds of the present invention (11 and I2) showed the better balance between dynamic rigidity and tensile properties.

[0342] Example 2

[0343] Elastomeric compounds were prepared according to the recipes of the reported in the following Table 2.1. The amounts are expressed in phr. The amounts in parenthesis are expressed in percent by weight with respect to the total weight of the compositions.

[0344] Sustainable polyesters were physically mixed with 50 wt% of silica with Speedmixer instrument for 8 minutes at 3,000 rpm.

[0345] Stirene-butadiene rubber and natural rubber were first introduced in the internal mixer, Brabender® type, and mixed for 1 minute at 140°C. After that, the sustainable polyester-silica physical mixture and silane were added at 140°C and mixed for 1 minute. Then, remaining percentage (50%) of silica, carbon black, and stearic acid were added at 140°C and mixed for 1 minute. Then, zinc oxide and 6PPD were added and mixed for 3 minutes.

[0346] The obtained compound was discharged, and the internal mixer temperature lowered to 70°C. At this temperature, the compound was reloaded and mixed for 1 minute. After that, TBBS and sulphur were added and mixed for 2 minutes at 70°C. At the end of the mixing, the elastomeric compound was unloaded.

[0347] TABLE 2.1

[0348] SBR1 styrene-butadiene rubber partially coupled to Si, comprising 25% by weight of styrene and 63% by weight of vinyl with respect to the butadiene content, produced by anionic polymerisation in solution using an organo-lithium initiator; extended with 37.5 parts of TDAE oil for every 100 parts of dry polymer (SPRINTAN™ SLR 4630; Trinseo)

[0349] SBR2 functionalized styrene butadiene copolymer - microstructure with 21 % styrene and 62.5% vinyl on the butadiene fraction (SPRINTAN™ SLR 4602; Trinseo)

[0350] NR natural rubber (Standard Thai Rubber STR 20 - Thaiteck Rubber);

[0351] Silica Zeosil® 1165 MP, standard grade with surface area of approx. 175 m2 / g from Solvay;

[0352] Silane TESPT, bis[3-(triethoxysilyl)propyl]tetrasulphide JH-S69 from ChemSpec Ltd.;

[0353] CB Carbon black N326, Cabot Corporation

[0354] 6PPD N-(1 ,3-dimethylbutyl)-N’-phenyl-p-phenylene-diamine SANTOFLEX 6PPD from EASTMAN

[0355] ZnO Standard Zn oxide from A-Esse

[0356] TBBS N-tert-butyl-2-benzothiazole sulfonamide, (Lanxess Deutschland GmbH, Germany)

[0357] Sulfur Sulphur 98.50% (1% oil) - Zolfindustria

[0358] The resulting elastomeric compounds were tested according to the abovedescribed procedures. The results are summarized below. Results The results of MDR rheometric analysis are reported in the following Table

[0359] 2.2 and illustrated in Figure 7.

[0360] TABLE 2.2

[0361] The compounds containing the sustainable polyesters of the present invention (11 -13) showed ML value lower than the ML of reference compound (R1 ) containing only the traditional elastomers. The ML value is an index of compound viscosity. Hence, all the compounds containing the polyesters have similar viscosities and could have similar processing behavior. This can be attributed to the use of the low molecular weight polyester in place of the high molecular weight SBR.

[0362] The compounds containing the sustainable polyesters of the present invention (11-13) showed MH value (and MH - ML values) similar to the MH (and MH - ML values) of reference compound (R1 ). It appears that the torque values can be tuned by changing the chemical composition of the polyesters.

[0363] The values of tsiare slightly higher for the compounds containing the sustainable polyesters of the present invention (11 -13). A longer scorch time is a positive feature for a compound.

[0364] At the same time, also the values of too are higher for the compounds containing the sustainable polyesters of the present invention (11 -13), though the difference is not remarkable. The higher crosslinking times can be attributed to the lower amount of a high molecular weight polymer. Indeed, the crosslinking degree is estimated by measuring a torque.

[0365] The curing rate of the reference compound (R1 ) lies within the values of the curing rate of the compounds of the present invention (11 -13). It appears that the curing rate can be tuned by changing the chemical composition of the polyesters.

[0366] The results of dynamic-mechanical analysis in the shear mode are reported in the following Table 2.3.

[0367] TABLE 2.3

[0368] The compounds containing the sustainable polyesters of the present invention (11 -13) showed G'Y=o.4% and G'Y=25% value higher than the G'Y=o.4% and G'Y=25% values of the reference compound (R1 ).

[0369] The AG' I G'Y=o.4% value for the compounds containing the sustainable polyesters of the present invention (11 -13) is higher than the AG' I G'Y=o.4% value of the reference compound (R1 ).

[0370] However, the Tan delta max values for all the compounds remains in a narrow range.

[0371] The results of dynamic-mechanical analysis in the axial mode are reported in the following Table 2.4.

[0372] TABLE 2.4

[0373] The compounds containing the sustainable polyesters of the present invention (11 -13) showed tan delta values substantially in line with the tan delta value of the reference compound (R1 ). They are only slightly lower at low temperature and slightly higher at high temperature.

[0374] The polyesters appear as ingredients suitable to reduce the hysteresis of a silica-based compound. In fact, the higher dynamic rigidity (E’ values) of the compounds of the present invention (11 -13) would allow to reduce the amount of filler, hence the Tan delta of the compounds.

[0375] The results of tensile test are reported in the following Table 2.5.

[0376] TABLE 2.5

[0377] The compounds containing the sustainable polyesters of the present invention (11 -13) showed similar stress-strain curves and demonstrated better ultimate properties than the reference compound (R1 ), which is very surprising as a part of the high molecular weigh dienic polymer was substituted with a much lower molecular weight polyester polymer. Example 3

[0378] The recipes of the elastomeric compounds are reported in the following Table 3.1 . The amounts are expressed in phr. The amounts in parenthesis are expressed in percent by weight with respect to the total weight of the compositions.

[0379] Natural rubber and styrene-butadiene rubber were first introduced in the internal mixer, Brabender® type, and mixed for 2 minutes at 150°C. Then, silica, stearic acid, and silane was added at 150°C and mixed for 3 minutes.

[0380] The obtained compound was discharged, and the internal mixer temperature lowered to 70°C. At this temperature, the compound was reloaded, added with the bio-based polyesters, and mixed for 1 minute. Then, zinc oxide and 6PPD were added and mixed for another minute. After that, TBBS and Sulfur were added and mixed for 1 minutes at 70 °C. At the end of the mixing, the elastomeric composite was unloaded. TABLE 3.1 SBR1 styrene-butadiene rubber partially coupled to Si, comprising 25% by weight of styrene and 63% by weight of vinyl with respect to the butadiene content, produced by anionic polymerisation in solution using an organo-lithium initiator; extended with 37.5 parts of TDAE oil for every 100 parts of dry polymer (SPRINTAN™ SLR 4630; Trinseo)

[0381] NR natural rubber (Standard Thai Rubber STR 20 - Thaiteck Rubber);

[0382] Silica Zeosil® 1165 MP, standard grade with surface area of approx. 175 m2 / g from Solvay;

[0383] Silane TESPT, bis[3-(triethoxysilyl)propyl]tetrasulphide JH-S69 from ChemSpec Ltd.;

[0384] 6PPD N-(1 ,3-dimethylbutyl)-N’-phenyl-p-phenylene-diamine SANTOFLEX 6PPD from EASTMAN

[0385] ZnO Standard Zn oxide from A-Esse

[0386] TBBS N-tert-butyl-2-benzothiazole sulfonamide, (Lanxess Deutschland GmbH, Germany)

[0387] Sulfur Sulphur 98.50% (1% oil) - Zolfindustria

[0388] The resulting elastomeric compounds were tested according to the abovedescribed procedures. The results are summarized below. Results

[0389] The results of MDR rheometric analysis are reported in the following Table 3.2.

[0390] TABLE 3.2 The compounds containing the sustainable polyesters (C1-C3) and the reference compound (R1 ) without sustainable polyesters showed very similar values of the parameters obtained from the curing experiments.

[0391] The results of dynamic-mechanical analysis in the shear mode are reported in the following Table 3.3.

[0392] TABLE 3

[0393] The compounds containing the sustainable polyesters (C1 -C3) and the reference compound (R1 ) without sustainable polyesters showed very similar values of the parameters obtained from the strain sweep experiments performed by applying the stress in the shear mode.

[0394] The results of dynamic-mechanical analysis in the axial mode are reported in the following Table 3.4. TABLE 4 The compounds containing the sustainable polyesters (C1 -C3) and the reference compound (R1) without sustainable polyesters showed similar values, i.e., values differing less than 10% of the reference value, of E’ and very similar values of Tan delta, determined by applying the stress in the axial mode.

[0395] The results of tensile test are reported in the following Table 3.5.

[0396] TABLE 3.5

[0397] The compounds containing the sustainable polyesters (C1 -C3) and the reference compound (R1) without sustainable polyesters showed similar tensile properties, all values falling in the interval = reference value ±10%.

[0398] The sustainable polyesters used in low amount as ingredient of a silica- based composite based on S-SBR as the main rubber, led to negligible changes in the properties of the composite. The data of Table 3.5 demonstrated that compounds containing the sustainable polyesters of the present invention (C1 -C4) provided no difference adding 2 phr of such sustainable polyesters.

[0399] Example 4

[0400] Sustainable polyesters were physically mixed with 50 wt% of silica with Speedmixer instrument for 8 minutes at 3,000 rpm.

[0401] Stirene-butadiene rubber and natural rubber were first introduced in the internal mixer, Brabender® type, and mixed for 1 minutes at 140 °C. After that, the sustainable polyester-silica physical mixture and silane were added at 140°C and mixed for 1 minute. Then, remaining percentage (50%) of silica and stearic acid were added at 140°C and mixed for 3 minutes.

[0402] The obtained compound was discharged, and the internal mixer temperature lowered to 70°C. At this temperature, the compound was reloaded and mixed for 1 minute. Then, zinc oxide and 6PPD were added and mixed for another minute. After that, TBBS and sulphur were added and mixed for 2 minutes at 70°C. At the end of the mixing, the elastomeric compound was unloaded.

[0403] The recipes of the elastomeric compounds are reported in the following Table 4.1.

[0404] TABLE 4.1

[0405] SBR styrene-butadiene rubber partially coupled to Si, comprising 25% by weight of styrene and 63% by weight of vinyl with respect to the butadiene content, produced by anionic polymerisation in solution using an organo-lithium initiator; extended with 37.5 parts of TDAE oil for every 100 parts of dry polymer (SPRINTAN™ SLR 4630-SCHKOPAU; Trinseo) NR natural rubber (Standard Thai Rubber STR 20 - Thaiteck Rubber);

[0406] Silica Zeosil® 1165 MP, standard grade with surface area of approx. 175 m2 / g from Solvay;

[0407] Silane TESPT, bis[3-(triethoxysilyl)propyl]tetrasulphide JH-S69 from ChemSpec Ltd.;

[0408] 6PPD N-(1 ,3-dimethylbutyl)-N’-phenyl-p-phenylene-diamine SANTOFLEX 6PPD from EASTMAN

[0409] ZnO Standard Zn oxide from A-Esse

[0410] TBBS N-tert-butyl-2-benzothiazole sulfonamide, (Lanxess Deutschland GmbH, Germany)

[0411] Sulfur Sulphur 98.50% (1% oil) - Zolfindustria

[0412] The resulting elastomeric compounds were tested according to the abovedescribed procedures. The results are summarized below.

[0413] Results The results of MDR rheometric analysis are reported in the following Table 4.2.

[0414] TABLE 4.2

[0415] The compounds containing the sustainable polyesters of the present invention (11-12) showed higher tsi, lower too values and higher curing rate than the reference compound (R1 ) without the sustainable polyesters. Hence, they show a more efficient curing. Compounds 11 and I2 showed higher ML and lower MH, however without revealing dramatic differences.

[0416] This is probably due to the strong interaction of the sustainable polyesters with silica, which led to the increase of viscosity, promoted the formation of a network and prevented a strong reduction of the modulus. The results of dynamic-mechanical analysis in the shear mode are reported in the following Table 4.3.

[0417] TABLE 4.3

[0418] The compounds containing the sustainable polyesters of the present invention (11 -12) showed higher values of AG' I G' y=0.4% and of Tan delta at 70°C. These findings indicated the presence of a large extent of filler network. To reduce the filler network and to have lower values of the mentioned parameters, a lower amount of filler could be used.

[0419] The results of dynamic-mechanical analysis in the axial mode are reported in the following Table 4.4.

[0420] TABLE 4.4 The compounds containing the sustainable polyesters of the present invention (11 -12) showed higher dynamic modulus than the reference (R1 ) in all the temperature range, and also higher Tan delta values. To reduce the Tan delta values, the amount of filler should be reduced. This would be allowed by the higher dynamic rigidity.

[0421] The results of tensile test are reported in the following Table 4.5.

[0422] TABLE 4.5 The compounds containing the sustainable polyesters of the present invention (11 -12) showed lower values of stresses at all the elongations and lower ultimate properties, in particular in the case of ultimate stress, while elongation at break remained close to the reference compound. In some applications such deterioration of mechanical properties could still be acceptable, in view of the higher sustainability content of the compound, however the above data point to the fact that the sustainable polyesters of the present invention cannot be used as the main polymer, but rather in a well- defined interval between 2% and 25% weight.

Claims

1. CLAIMS1 . A vulcanizable elastomeric composition comprising:(i) at least one diene elastomeric polymer selected from the group of natural and synthetic diene elastomeric polymers,(ii) a reinforcing filler, and(iii) at least one vulcanizing agent, characterized in that said vulcanizable elastomeric composition further comprises an amorphous polyester obtained by the copolymerization of at least one diol, preferably at least two diols, at least one dicarboxylic acid, preferably at least two dicarboxylic acids, more preferably three dicarboxylic acids, and optionally at least one hydroxycarboxylic acid or cyclic lactones thereof, wherein said diol is selected from the group consisting of ethylene glycol, 1 ,3 propanediol, 1 ,2-propanediol, 1 ,4-butanediol, 1 ,3-butanediol, 1 ,2-butanediol, 2,3-butanediol, 1 ,5-pentanediol, 1 ,6-hexanediol, cis-1 ,4-butenediol, trans-1 ,4- butenediol, 1 ,8-octanediol, 1 ,10-decanediol, 1 ,12-dodecanediol, 1 ,16- hexadecanediol, and 2,5-furandimethanol, said dicarboxylic acid is selected from the group consisting of 2,5- furandicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, muconic acid, and 3,3-dithiodipropionic acid, said hydroxycarboxylic acid is selected from the group consisting of lactic acid, glycolic acid, mandelic acid and co-hydroxy acids having four to eighteen carbon atoms, wherein said amorphous polyester has a glass transition temperature ranging from -20° to -70°C and a number average molecular weight (Mn) ranging from 7,000 Da to 70,000 Da, and wherein the amount of said amorphous polyester ranges from 2% to 25% by weight with respect the total weight of the vulcanizable elastomeric composition.

2. A green tire structural component comprising a vulcanizable elastomeric composition according to claim 1 .

3. A tire for vehicle wheels comprising at least one structural component comprising a vulcanized elastomeric compound obtained by vulcanizing a vulcanizable elastomeric composition according to claim 1.

4. The elastomeric composition according to claim 1 , the structural component according to claim 2, or the tire for vehicle wheels according to claim 3, characterized in that said dicarboxylic acid is selected from the group consisting of 2,5-furandicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, succinic acid, adipic acid, sebacic acid, itaconic acid, and mixture thereof.

5. The elastomeric composition according to claim 1 , the structural component according to claim 2, or the tire for vehicle wheels according to claim 3, characterized in that said diol is selected from the group consisting of ethylene glycol, 1 ,3-propanediol, 1 ,4 butanediol, and mixture thereof.

6. The elastomeric composition according to claim 1 , the structural component according to claim 2, or the tire for vehicle wheels according to claim 3, characterized in that said hydroxycarboxylic acid is selected from the group consisting of lactic acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 8-hydroxycaprylic acid, 10-hydroxycapric acid, and cyclic lactones thereof.

7. The elastomeric composition according to claim 1 , the structural component according to claim 2, or the tire for vehicle wheels according to claim 3, characterized in that said amorphous polyester is schematically represented by the following formulas (1 ) to (10),(1 ) Ri-O-[OC-A1 -CO]ai-[O-D1 -O]di-R2(2) R2-[O-D1 -O]di-[CO-A1 -CO]ai-[O-D2-O]d2-R2(3) Ri-O-[OC-A1 -CO]ai-[O-D1 -O]di-[CO-A2-CO]a2-O-Ri(4) Ri-0-[0C-A1 -C0]ai-[0-D1 -O]di-[CO-A2-CO]a2-[O-D2-O]d2-R2(5) Ri-0-[0C-A1 -C0]ai-[0-D1 -O]di-[CO-A2-CO]a2-[O-D2-O]d2-[OC-A3- C0]a3-0-Rl(6) Ri-0-[0C-A1 -C0]ai-[0-HA1 -C0]hai-[0-D1-0]di-R2(7) R2-[0-D1 -0]di-[C0-A1 -C0]ai-[0-HA1 -CO]hai-[O-D2-O]d2-R2(8) Ri-0-[0C-A1 -C0]ai-[0-HA1 -C0]hai-[0-D1 -O]di-[CO-A2-CO]a2-O-Ri(9) Ri-0-[0C-A1 -C0]ai-[0-HA1 -C0]hai-[0-D1 -O]di-[CO-A2-CO]a2-[O-D2-O]d2-R2(10) Ri-O-[OC-A1 -CO]ai-[O-HA1 -CO]hai-[O-D1 -O]di-[CO-A2-CO]a2-[O-D2- O]d2-[OC-A3-CO]a3-O-Ri wherein any one of A1 , A2, and A3, different from each other, is a residue of a dicarboxylic acid selected from the group consisting of 2,5- furandicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, muconic acid, and 3,3-dithiodipropionic acid, any one of D1 and D2, different from each other, is a residue of a diol selected from the group consisting of ethylene glycol, 1 ,3 propanediol, 1 ,2- propanediol, 1 ,4-butanediol, 1 ,3-butanediol, 1 ,2-butanediol, 2,3-butanediol,1 .5-pentanediol, 1 ,6-hexanediol, cis-1 ,4-butenediol, trans-1 ,4-butenediol, 1 ,8- octanediol, 1 ,10-decanediol, 1 ,12-dodecanediol, 1 ,16-hexadecanediol, and2.5-furandimethanol,HA1 is a residue of a hydroxycarboxylic acid selected from the group consisting of lactic acid, glycolic acid, mandelic acid and co-hydroxy acids having four to eighteen carbon atoms,R1 is a hydrogen atom or a pyrrole residue having the following formula (I),wherein R4 and R5, equal or different from each other, being hydrogen atom or a C1 -C3 alkyl group, and n being an integer from 1 to 3,R2is a hydrogen atom or a pyrrole residue having the following formula (II),wherein R4and Rs, equal or different from each other, being hydrogen atom or a C1 -C3 alkyl group, and n being an integer from 1 to 3, at least one of A1 , A2, A3, D1 , and D2 comprises a divalent carbon residue having formula -CHR3-, wherein R3 is a hydrogen atom or a pyrrole residue having the following formula (III),wherein R4and Rs, equal or different from each other, are hydrogen atom or a C1-C3 alkyl group, X is oxygen or sulfur atom, n is an integer from 1 to 3, and m is an integer from 0 to 3, and the indexes a1 , a2, a3, d1 , d2, and ha1 represent a mole fraction ranging from 0.05 to 0.95 of the respective monomers within the polyester, wherein the sum thereof is always equal to 1 in each of said formula (1 ) to (10).

8. The elastomeric composition according to claim 1 , the structural component according to claim 2, or the tire for vehicle wheels according to claim 3, characterized in that in the amorphous polyester as defined in claim 7 at least one of R1, R2, and R3 is different from hydrogen atom.

9. The elastomeric composition according to claim 1 , the structural component according to claim 2, or the tire for vehicle wheels according to claim 3, characterized in that said amorphous polyester has a glass transition temperature ranging from -25° to -65°C, preferably from -30° to -60°C.

10. The elastomeric composition according to claim 1 , the structural component according to claim 2, or the tire for vehicle wheels according toclaim 3, characterized in that said amorphous polyester has a number average molecular weight (Mn) ranging from from 9,000 Da to 50,000 Da, preferably from 10,000 Da to 40,000 Da.

11. The structural component according to claim 2, or the tire for vehicle wheels according to claim 3, characterized in that said structural component is selected from the group consisting of tread band (109), cap (109a), base (111 ), and mini-sidewall (110).

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