DESCRIPTION

The present invention relates to a tyre for vehicle wheels.

The invention also relates to a textile reinforcing cord to be used in tyres for vehicle wheels.

The tyre of the invention is, preferably, a tyre for sports vehicle wheels, in particular high and ultra-high performance vehicles.

Tyres for high and ultra-high performance vehicles, commonly defined as "HP" or "UHP" tyres, are in particular those that allow speeds of over 190 km/h, up to more than 300 km/h, to be reached. Examples of such tyres are those carrying speed codes "T", "U", "H", "V", "Z","W", "Y", according to the E.T.R.T.O. (European Tyre and Rim Technical Organisation) standard and racing tyres, in particular for high-power four-wheeled vehicles. Typically, tyres that carry the aforementioned speed codes have a section width equal to or greater than 185 mm, preferably comprised between 195 mm and 385 mm, more preferably comprised between 195 mm and 355 mm. Such tyres are preferably mounted on rims having fitting diameters equal to or greater than 13 inches, preferably not greater than 24 inches, more preferably comprised between 16 inches and 23 inches.

However, the tyre of the invention can be used in vehicles other than the aforementioned automobiles, for example in sports motorcycles intended to offer high performance in terms of power, comfort and mileage, like for example motorcycles of the "Sport Touring" type, i.e. motorcycles designed to be used on different types of terrains and with different road surface conditions.

Typically, motorcycles of the Sport Touring type are motorcycles with large piston displacement (for example 800 cm ³ or more) and/or high power (for example 100-120 horsepower or more). The tyre of the invention comprises one or more structural components containing textile reinforcing cords including filaments made of a recycled material.

PRIOR ART

Textile reinforcing cords to be used in tyres for vehicle wheels and comprising filaments made of a recycled material are described for example in EP 2576245 Bl. These reinforcing cords in particular comprise two yarns twisted together, one of which comprises filaments made of recycled PET. It is provided for the other yarn to comprise filaments made of a non-recycled material, like for example nylon, aramid, Arselon, PEEK or polyketone (POK).

WO 2020254215 Al describes textile reinforcing cords for tyres made by twisting a yarn comprising filaments made of recycled PET with a yarn comprising filaments made of nylon.

Another type of textile reinforcing cord comprising filaments made of a recycled material and to be used in tyres for vehicle wheels is described in EP 2708380 Bl. Such a reinforcing cord comprises at least one yarn comprising both filaments made of bio-based PET and filaments made of recycled PET. Such a yarn can be twisted with another yarn having filaments that can be made of bio-based PET or other textile materials, preferably nylon.

SUMMARY OF THE INVENTION

Throughout the present description and in the following claims, when reference is made to certain values of angles, these are deemed to be absolute values, i.e. both positive values and negative values with respect to a plane or direction of reference, unless specified otherwise.

Moreover, when reference is made to any range of values comprised between a minimum value and a maximum value, the aforementioned minimum and maximum values are deemed to be included in the aforementioned range, unless expressly stated to the contrary.

Moreover, all of the ranges include any combination of the described minimum and maximum values and include any intermediate range, even if not specifically expressly described.

Even if not expressly indicated, any numerical value is deemed to be preceded by the term "about" to also indicate any numerical value that differs slightly from that described, for example to take into account the dimensional tolerances typical of the field of reference.

Hereinafter, the following definitions apply.

The term "motorcycle tyre" is used to indicate a tyre having a high curvature ratio (typically greater than 0.20) and capable of reaching high camber angles during cornering.

The term "curvature ratio" is used to indicate the ratio between the distance comprised between the radially highest point of the tread band and the maximum width of radial section (also called "maximum cord") of the tyre, and the same maximum width of the tyre, in a cross section thereof.

The term "maximum width of radial section", or "maximum cord", is used to indicate the maximum width of the profile of the tyre, i.e. the dimension of the segment having the two axially outermost points of the profile of the tread band as extremities.

The term "equatorial plane" of the tyre is used to indicate a plane perpendicular to the rotational axis of the tyre and that divides the tyre into two symmetrically equal parts.

The terms "radial" and "axial" and the expressions "radially inner/outer" and "axially inner/outer" are used with reference to a direction substantially parallel to the equatorial plane of the tyre and to a direction substantially perpendicular to the equatorial plane of the tyre, respectively, i.e. to a direction substantially perpendicular to the rotation axis of the tyre and to a direction substantially parallel to the rotation axis of the tyre, respectively.

The terms "circumferential" and "circumferentially" are used with reference to the direction of annular extension of the tyre, i.e. to the rolling direction of the tyre, which corresponds to a direction lying on a plane coinciding with or substantially parallel to the equatorial plane of the tyre.

The term "substantially axial direction" is used to indicate a direction inclined, with respect to the equatorial plane of the tyre, by an angle comprised between 70° and 90°.

The term "substantially circumferential direction" is used to indicate a direction oriented, with respect to the equatorial plane of the tyre, at an angle comprised between 0° and 10°.

The term "elastomeric material" or "elastomer" is used to indicate a material comprising a vulcanizable natural or synthetic polymer and a reinforcing filler, wherein such a material, at room temperature and after having been subjected to vulcanization, can have deformations caused by a force and is capable of quickly and energetically recovering the substantially original shape and size after the elimination of the deforming force (according to the definitions of standard ASTM D1566- 11 Standard Terminology Relating To Rubber).

The term "reinforcing cord", or more simply "cord" is used to indicate an elongated element consisting of one or more elongated elements (also called "wires", "yarns" or "strands") possibly coated with, or incorporated in, a matrix of elastomeric material.

Hereinafter, the term "wire" will be used to refer to a single elongated element consisting of a single textile filament (in this case the term "monofilament textile wire" will also be used), whereas the term "yarn" will be used to refer to an elongated element made through aggregation of a plurality of textile filaments (in this case the term "multifilament textile yarn" will also be used). Each filament can also be called "fiber".

The yarns can have one or more "ends", where the term "end" is used to indicate a bundle of filaments twisted together. For example, a single end or at least two ends twisted together can be foreseen.

The yarns can be identified with a symbol that represents the textile material, the linear density of the fiber used and the number of ends that form the yarn. For example, a yarn with ends made of PET (polyethylene terephthalate) identified with PET 1672 indicates a yarn comprising fibers made of PET with linear density 1670 dtex, formed of two ends twisted together.

Two yarns are deemed "twisted" to one another or with one another when each of the two yarns is wound on the other yarn, i.e. when each of the two yarns extends around the other yarn along a non- rectilinear trajectory, in particular along a helical trajectory or a spiral trajectory. This definition does not include the case in which one of the two yarns (first yarn) is wound around the other yarn (second yarn) but not vice-versa. In this case, the reinforcing cord is not obtained by twisting together the two yarns but rather by winding the first yarn around the second yarn. In such a reinforcing cord the first yarn extends around the second yarn along a non-rectilinear trajectory, in particular a helical trajectory or a spiral trajectory, whereas the second yarn always extends in a radially inner position with respect to the first yarn along a substantially rectilinear trajectory.

In a yarn, a monofilament textile wire is deemed "incorporated" in the filaments of the yarn when the monofilament textile wire is arranged or embedded between the filaments of the yarn. This definition does not include the case in which the monofilament textile wire defines a central core around which the filaments of the yarn are wound helically or in a spiral.

The term "strand" is used to indicate the union of at least two wires or yarns to constitute an elongated element intended to be twisted with at least another elongated element to form the reinforcing cord, the at least two elongated elements that form the reinforcing cord being equal to each other or different from one another.

The term "diameter" of a reinforcing cord, or of a wire or yarn, is used to indicate the diameter measured as prescribed by the BISFA E10 method (The International Bureau For The Standardization Of Man- Made Fibres, Internationally Agreed Methods For Testing Steel Tyre Cords, 1995 edition).

In the case of yarns, the "diameter" of a yarn is the diameter of an ideal circumference that circumscribes all the filaments that define the yarn.

The term "linear density" or "count" of a cord or of a wire/yarn is used to indicate the weight of the cord or of the wire/yarn per unit length. The linear density can be measured in dtex (grams per 10 km of length).

In this description, two materials are deemed different also when one is a recycled material and the other is a corresponding nonrecycled material. Therefore, for example, a recycled PET is a material different from a non-recycled PET.

The term "recycled material" is used to indicate a plastic material obtained from refuse or industrial waste products made of a corresponding material of plastic origin (typically, even if not necessarily, of fossil origin) and subjected to suitable mechanical and/or chemical and/or thermal treatments to be able to then give rise to re-usable products.

The term "non-recycled material" is used to indicate a plastic material of fossil origin.

The term "biologically-based material" is used to indicate a material that is not of fossil origin and that is not obtained from refuse or industrial waste products, but that is obtained from renewable sources, like for example farming and forestry products that are cultivated and/or used by people for purposes different from human or animal nutrition.

Hereinafter, when reference is made to a percentage of a product made of recycled or biologically-based material, we refer to the weight of such a product with respect to the weight of the cord/strand/yarn/wire that incorporates such a product. Therefore, for example, a cord/strand/yarn/wire made of a material that is 65% recycled or biologically-based indicates a cord/strand/yarn/wire in which 65% of the total weight of the cord/strand/yarn/wire is made of a recycled or biologically-based material and the remaining 35% of the total weight of the cord/strand/yarn/wire is made of a material of fossil origin.

The term "number of twists" is used to indicate the number of twists applied to a cord/strand/yarn/wire per unit length of cord/strand/yarn/wire. The number of twists is indicated with TPI (twists per inch) and therefore indicate the number of twists in an inch of cord/strand/yarn/wire. In the case of wires and/or yarns and/or strands that must be twisted, the twist is applied before the cord is made.

The terms "breaking load" and "elongation at break" of a cord/strand/yarn/wire are used to indicate, respectively, the load and the percentage elongation at which the cord/strand/yarn/wire breaks, evaluated in accordance with the BISFA (Bureau International pour la Standardisation des Fibres Artificielles) standard relative to the material subjected to testing according to the definition given below.

The term "modulus" is used to indicate the ratio between load (or force) and elongation measured at any point of a load-elongation curve according to the BISFA standard relative to the material subjected to testing according to the definition given below. Such a curve is drawn by calculating the first derivative of the load-elongation function that defines the aforementioned curve, normalized to the linear density expressed in Tex. The modulus is therefore expressed in cN/Tex or MPa. In a load-elongation graph, the modulus is identified by the slope of the aforementioned curve with respect to the X-axis.

The term "tenacity" of a reinforcing cord or of a strand/yarn/wire is used to indicate the ratio calculated between the modulus and the linear density. Tenacity is measured according to the BISFA standard relative to the material subjected to testing as indicated below.

For the purposes of the present invention, for the measurement of the linear density and for determining the tensile (or mechanical) properties, in particular the tenacity, reference is made to flat wires, with no twists applied in the testing phase, according to the tests regulated by the BISFA standard. In particular:

- for Polyester (PET), reference is made to BISFA - Testing methods for polyester yarns - 2004 edition:

• Determination of the linear density - Chapter 6 - Procedure A;

• Determination of the tensile properties - Chapter 7 - Procedure A;

• Preparation of laboratory samples: Preparation of samples under relaxation - paragraph 7.4.1.1 => preparation of samples on collapsible reel;

• Preparation of laboratory samples and performance of testing: Manual test - paragraph 7.5.2.1 => c);

• Start procedure => e) pretension at the start of procedure;

• Tractions carried out with Zwick - Roell Z010 dynamometer.

- for Nylon (NY), reference is made to BISFA - Testing methods for polyamide yarns - 2004 edition:

• Determination of the linear density - Chapter 6 - Procedure A;

• Determination of the tensile properties - Chapter 7 - Procedure A;

• Preparation of laboratory samples: Preparation of samples under relaxation - paragraph 7.4.1.1 => preparation of samples on collapsible reel;

• Preparation of laboratory samples and performance of testing: Manual test - paragraph 7.5.2.1 => c);

• Start procedure => e) pretension at the start of procedure;

• Tractions carried out with Zwick - Roell Z010 dynamometer.

The term "radial carcass structure" is used to indicate a carcass structure comprising a plurality of reinforcing cords, each of which being oriented, in a crown portion of the tyre, along a substantially axial direction. Such reinforcing cords can be incorporated in a single carcass ply or in a plurality (preferably two) of carcass plies radially juxtaposed over one another.

The term "crossed belt structure" is used to indicate a belt structure comprising a first belt layer including reinforcing cords substantially parallel to one another and inclined, with respect to the equatorial plane of the tyre, by a predetermined angle and at least one second belt layer arranged in a radially outer position with respect to the first belt layer and including reinforcing cords substantially parallel to one another but oriented, with respect to the equatorial plane of the tyre, with opposite inclination to that of the cords of the first belt layer.

The term "zero degrees reinforcing layer" is used to indicate a reinforcing layer comprising at least one reinforcing cord wound on the belt structure (in the case of tyres for automobiles) or on the carcass structure (in the case of tyres for motorcycles) according to a substantially circumferential winding direction. In motorcycle tyres, the zero degrees reinforcing layer can itself define the "belt structure" of such tyres or can be replaced by two juxtaposed reinforcing layers that define a crossed belt structure.

The term "structural component" of a tyre is used to indicate any ply or layer of the tyre containing reinforcing cords, like for example a carcass ply of automobile or motorcycle tyres, or a belt layer of automobile tyres, or a zero-degrees reinforcing layer (or a crossed belt structure) of a motorcycle tyre, or a stiffening layer associated with a carcass ply of automobile tyres at or close to a respective turned end edge of the carcass ply and indicated below as "flipper" and "chafer".

The term "thread count" of a structural component of the tyre is used to indicate the number of reinforcing cords per unit length provided in such a component. The thread count can be measured in cords/dm (number of cords per decimeter).

Hereinafter, when the adhesion capability of a textile reinforcing cord, and more generally of elongated elements, to the elastomeric material is discussed, it is deemed to refer to the adhesion capability given to the textile reinforcing cord solely by its shape or structure, thus without considering surface coating treatments through adhesive compositions. In the field of tyre production it is indeed known to use adhesive compositions, for example Resorcinol-Formaldehyde-Latex (RFL) composition, in order to promote the adhesion between the elongated elements and the elastomeric material and thus ensure the performance properties of the tyre during use. Such RFL-based adhesive compositions are applied to the polymeric elongated elements, generally by immersion in an aqueous RFL-based solution, i.e. a rubber latex emulsion in an aqueous solution of resorcinol and formaldehyde (or pre- condensed resin obtained from reaction between resorcin and formaldehyde). Some materials, such as rayon and aliphatic polyamides, already acquire optimal properties for adhesion to the elastomeric material through a single immersion in an RFL-based bath (dipping, one- step process) whereas others, such as polyesters or aromatic polyamides, bond with greater difficulty to the elastomeric material and therefore take advantage of special physical or chemical activating pretreatments. For example, elongated elements made of polyester or aromatic polyamides are subjected to a surface pre-activation through pre-treatment with a first activating bath (pre-dipping, two-step process) or through pretreatments with ionizing rays, with plasma or with solvents.

Tyres for sports automobiles and for motorcycles are required to have a high capability to adhere to the ground, so as to be able to effectively discharge to the ground the high drive torque which they are subjected to and, therefore, to achieve a high thrust and an effective braking force. Such tyres must also be light and provide an adequate response to the stresses which they are subjected to during travel in a straight line and during cornering.

Sports vehicle tyres typically comprise a radial carcass structure, a crossed belt structure arranged in a radially outer position with respect to the carcass structure, a zero degrees reinforcing layer arranged in a radially outer position with respect to the crossed belt structure and a tread band arranged in a radially outer position with respect to the zero degrees reinforcing layer.

In tyres for sports motorcycles, the belt structure may or may not be crossed. In the second case the belt structure defines a zerodegrees reinforcing layer.

The carcass structure is intended to provide the tyre with the desired characteristics of integrity and structural strength, whereas the crossed belt structure, in addition to contribute to provide the aforementioned characteristics of integrity and structural strength, is intended to transfer to the carcass structure the lateral and longitudinal stresses which the tyre is subjected to during travel upon contact with the road surface, so as to provide the tyre with the desired performance characteristics (i.e. grip, driving stability, controllability, directionality, road holding). The zero-degrees reinforcing layer, on the other hand, is intended to limit the radial deformation of the belt structure (in automobile tyres) or of the carcass structure (in motorcycle tyres).

In order to achieve the aforementioned structural and performance characteristics, one or more reinforcing layers are provided in the carcass structure and in the belt structure of automobile tyres and in the carcass structure of motorcycle tyres (in the carcass structure the reinforcing layer corresponds to one or more "carcass plies"), each reinforcing layer comprising a plurality of reinforcing cords suitably inclined with respect to the circumferential or rolling direction, whereas in the zero degrees reinforcing layer reinforcing cords oriented substantially parallel to the circumferential or rolling direction are provided.

At least some of the aforementioned reinforcing cords are textile reinforcing cords.

Typically, the aforementioned textile reinforcing cords comprise filaments made of plastic material of fossil origin. In many cases, the filaments are made of PET, due to the wide availability of such a material at low cost.

For example, the Applicant uses, both in the carcass structure of many of its automobile or motorcycle tyres and in the belt structure of many of its automobile tyres, textile reinforcing cords obtained by twisting together two yarns, each yarn consisting of a plurality of filaments made of PET of fossil origin.

The Applicant has however observed that the use of plastic materials of fossil origin is increasingly criticized due to the negative impact that they have on the environment.

Consequently, the Applicant has considered the possibility of using in its tyres textile reinforcing cords at least partially made of recycled or biologically-based material.

The Applicant has found that by twisting together at least two yarns made of an at least partially recycled or biologically-based material, wherein at least one of which comprises a plurality of filaments and at least one monofilament textile wire, it is possible to make textile reinforcing cords with a reduced environmental impact suitable for being used in the carcass structure of automobile and motorcycle tyres and/or in the crossed belt structure of automobile tyres, depending on the number and the diameter of the monofilament textile wires.

Since filaments are more suitable than monofilament textile wires for adhering to the surrounding elastomeric material, the Applicant has also thought of embedding the monofilament textile wire(s) in the filaments of the respective yarn.

Therefore, in a first aspect thereof the present invention relates to a tyre for vehicle wheels.

Preferably, the tyre comprises at least one structural component including a plurality of textile reinforcing cords.

Preferably, at least some of said textile reinforcing cords comprise at least two yarns twisted together.

Preferably, at least one first yarn of said at least two yarns comprises a plurality of first filaments.

Preferably, said first filaments are made of an at least partially recycled or biologically-based material.

Preferably, the structural component comprises at least one first monofilament textile wire.

Preferably, said at least one first yarn comprises said at least one first monofilament textile wire.

Preferably, in any cross section of said at least one first yarn said at least one first monofilament textile wire is at least partially embedded in said first filaments.

Preferably, at least some of said first filaments are made of an at least partially recycled or biologically-based material.

Preferably, said at least one first monofilament textile wire is made of an at least partially recycled or biologically-based material.

In a second aspect thereof, the invention relates to a textile reinforcing cord.

Preferably, the textile reinforcing cord comprises at least two yarns twisted together.

Preferably, at least one first yarn of said at least two yarns comprises a plurality of first filaments.

Preferably, the textile reinforcing cord comprises at least one first monofilament textile wire.

Preferably, said at least one first yarn comprises said at least one first monofilament textile wire.

Preferably, in any cross section of said at least one first yarn said at least one first monofilament textile wire is at least partially embedded in said first filaments.

Preferably, at least some of said first filaments are made of an at least partially recycled or biologically-based material.

Preferably, said at least one first monofilament textile wire is made of an at least partially recycled or biologically-based material.

The Applicant has verified that it is possible to make textile reinforcing cords of the type described above thanks to the fact that monofilament textile wires and yarns made at least partially from recycled or biologically-based material are available on the market.

In accordance with the invention, such reinforcing cords can be made totally from recycled material, or totally from biologically-based material, or partially from recycled material and partially from biologically-based material, or partially from recycled material and partially from material of fossil origin, or partially from biologically-based material and partially from material of fossil origin, or using recycled material and biologically-based material and material of fossil origin. In all these cases, the provision in the reinforcing cords of filaments and/or of monofilament textile wires made of a recycled and/or biologically- based material in place of corresponding filaments and monofilament textile wires made of a material of fossil origin makes it possible to obtain the desired benefits in terms of environmental sustainability. Such benefits are greater the greater the percentage of recycled or biologically- based material used.

The Applicant has found that, indeed, the aforementioned textile reinforcing cords can replace the textile reinforcing cords made with the same materials, but of fossil origin, currently used in tyres.

In particular, the Applicant has found that, by suitably selecting the number and the diameter of the monofilament textile wires contained in the aforementioned reinforcing cords, the latter can have mechanical characteristics equivalent to those of conventional reinforcing cords made with the same plastic material, but of fossil origin, thus being suitable for being used both in the carcass structure of automobile and motorcycle tyres and in the belt structure of automobile tyres (in both or only one of the aforementioned structures) of all types of vehicles where high performance is required, thus not only in sports automobiles but also for example in sports motorcycles.

The Applicant also believes that the textile reinforcing cords of the invention can be used also or only in other structural components of automobile tyres, like for example in the structural components of automobile tyres that are described below and are indicated as "flipper" and "chafer".

In accordance with the invention, the reinforcing cord described above can comprise two or more yarns twisted together. Each yarn can in turn comprise a single end or a plurality of ends twisted together. Many yarns can be twisted together to form many strands twisted together. In this last case the reinforcing cord thus comprises many strands twisted together, each strand in turn comprising at least two yarns twisted together, each yarn in turn comprising one or more ends twisted together, wherein at least one of said ends comprises a monofilament textile wire embedded among the filaments that define such an end.

In at least one of the aforementioned aspects, the present invention can have at least one of the preferred characteristics described hereinafter.

Preferably, in any cross section of said at least one first yarn said at least one first monofilament textile wire is completely embedded in said first filaments, so as to maximize the adhesion of the reinforcing cord to the surrounding elastomeric material.

Preferably, all the filaments of the first yarn are made of at least partially recycled and/or biologically-based material, so as to increase the beneficial effects with regard to the environment.

Preferably, the first filaments are made of at least partially recycled or biologically-based PET and/or nylon. The choice of the filaments material can be made depending on the availability on the market and/or the relative cost at the time of selection.

Preferably, the material of said at least one first monofilament textile wire is at least partially recycled or biologically-based PET and/or nylon.

More preferably, the material of said first filaments is identical to that of said at least one first monofilament textile wire.

Preferably, at least one second yarn of said at least two yarns comprises a plurality of second filaments made of an at least partially recycled or biologically-based material.

Preferably, all the filaments of the second yarn are made of a recycled or biologically-based material.

Preferably, the material of said second filaments is at least partially recycled or biologically-based PET and/or nylon.

More preferably, the material of said second filaments is identical to that of said first filaments.

In preferred embodiments, said at least one second yarn further comprises at least one second monofilament textile wire.

Preferably, in any cross section of said at least one second yarn said at least one second monofilament textile wire is at least partially embedded in said second filaments.

More preferably, in any cross section of said at least one second yarn said at least one second monofilament textile wire is completely embedded in said second filaments.

Preferably, said at least one second monofilament textile wire is made of a recycled or biologically-based material.

More preferably, the material of said at least one second monofilament textile wire is at least partially recycled or biologically- based PET and/or nylon.

Even more preferably, the material of said at least one second multifilament textile wire is identical to that of said at least one first multifilament textile wire.

In preferred embodiments, said textile reinforcing cords consist of a single first yarn and of a single second yarn.

Preferably, the first yarn comprises a single monofilament textile wire, preferably identical to said first monofilament textile wire.

Preferably, said second yarn comprises a single monofilament textile wire, preferably identical to said second monofilament textile wire. In some embodiments, said at least one structural component is a carcass ply.

In other embodiments of a tyre for automobiles, said at least one structural component is a stiffening layer associated with a carcass ply of a tyre for automobiles at or close to a respective turned end edge of the carcass ply, like for example a "flipper" and/or a "chafer".

In further embodiments, the textile reinforcing cords of the invention are used both in the carcass ply and in the aforementioned stiffening layer.

In further embodiments, said at least one structural component is a belt layer of a tyre for automobiles.

The textile reinforcing cords of the invention can therefore be used in the carcass ply, in the aforementioned stiffening layer, in the belt layer or in only some of the aforementioned structural components.

In first preferred embodiments, said at least one first monofilament textile wire has a diameter lower than, or equal to, 0.22 mm, more preferably lower than, or equal to, 0.21 mm, even more preferably lower than, or equal to, 0.20 mm.

The Applicant believes that in this way the contribution offered by the aforementioned monofilament textile wire with regard to the mechanical characteristics of the reinforcing cord can be considered negligible. Consequently, in the Applicant's opinion, a reinforcing cord made in this way is suitable for withstanding bending stresses but not compressive stresses and, therefore, it can replace the conventional reinforcing cords comprising only filaments of fossil origin currently used in the carcass structures of tyres for automobiles or motorcycles and/or in the flippers and/or in the chafers of tyres for automobiles.

According to the Applicant, moreover, the use of reinforcing cords comprising a monofilament textile wire with the aforementioned diameter values allows mono-ply carcass structures to be made having mechanical characteristics similar to those of conventional two-ply crossed carcass structures, with the same thread count.

In other embodiments, said at least one first monofilament textile wire and, if provided, also said at least one second monofilament textile wire, has a diameter greater than 0.22 mm, preferably greater than, or equal to, 0.25 mm, more preferably greater than, or equal to, 0.30 mm.

The Applicant believes that in this case the reinforcing cord has a stiffness suitable for allowing it to withstand the compressive stresses, such stiffness being greater the greater the diameter of the monofilament textile wire used and even greater when the reinforcing cord also comprises said at least one second monofilament textile wire. Consequently, in the Applicant's opinion, a reinforcing cord made in this way is suitable for being used in the crossed belt structures of tyres for automobiles in replacement of the current reinforcing cords comprising only multifilament textile yarns of fossil origin.

The Applicant also believes that the high stiffness of the aforementioned reinforcing cord, in addition to provide the reinforcing cord with a good behavior in terms of impact fatigue, also makes it possible to foresee thread counts lower than those typically provided in the case of use of conventional textile reinforcing cords comprising only multifilament textile yarns, with a consequent reduction in weight.

In further embodiments, the reinforcing cords of the invention comprise a first yarn including a first monofilament textile wire having a diameter lower than, or equal to, 0.22 mm, preferably lower than, or equal to, 0.21 mm, more preferably lower than, or equal to, 0.20 mm, for example equal to 0.19 mm and a second yarn including a second monofilament textile wire having a diameter greater than 0.22 mm, preferably greater than, or equal to, 0.25 mm, more preferably greater than, or equal to, 0.30 mm. Such reinforcing cords offer an excellent compromise between stiffness and resistance to fatigue and are suitable for being used both in the carcass structure of tyres for automobiles or motorcycles and in the belt structure of tyres.

Preferably, said at least one first yarn is twisted on itself with a predetermined first twisting pitch. The Applicant has found that such a provision contributes to optimizing the behavior under fatigue of the reinforcing cord.

Preferably, said first twisting pitch is equal to the twisting pitch of said at least two yarns.

Preferably, said at least one second yarn is twisted on itself with a second twisting pitch.

Preferably, said second twisting pitch is equal to the twisting pitch of said at least two yarns.

In some embodiments, in said at least one first yarn said at least one first monofilament textile wire is twisted on itself with a respective twisting pitch that, preferably, is equal to said twisting pitch. In this way, the incorporation of the monofilament textile wire in the filaments of the first yarn is maximized, to the benefit of the adhesion of the reinforcing cord to the surrounding elastomeric material.

In some embodiments, in said at least one second yarn said at least one second monofilament textile wire is twisted on itself with a respective twisting pitch that, preferably, is equal to said twisting pitch.

Preferably, the reinforcing cord is twisted on itself with a respective twisting pitch that can be equal to, or different from, the twisting pitch of the yarns and/or of the monofilament textile wires.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Further characteristics and advantages of the tyre of the present invention will become clearer from the following detailed description of preferred embodiments thereof, made with reference to the attached drawings. In such drawings:

- figure 1 is a schematic partial half-cross section view of a portion of a tyre for automobiles according to an embodiment of the present invention;

- figure 2 shows a radial cross section view of a motorcycle tyre according to an embodiment of the present invention;

- figure 3 is a schematic side view of a segment of an example of reinforcing cord in accordance with the present invention, such a reinforcing cord being used in the tyres of figures 1 and 2;

- figure 4 is an enlarged schematic view of a cross section of a first embodiment of the reinforcing cord of figure 3, such a cross section being taken on the section plane S-S indicated in figure 3;

- figure 5 is an enlarged schematic view of a cross section of a second embodiment of the reinforcing cord of figure 3, such a cross section being taken on the section plane S-S indicated in figure 3;

- figures 6-8 illustrate some graphs that show the load-elongation curves of reinforcing cords in accordance with the present invention and of conventional reinforcing cords.

Figure 1 shows only a part of an example embodiment of a tyre 100 for automobiles or four-wheeled vehicles in accordance with the present invention, the remaining part, which is not shown, being substantially identical and being arranged symmetrically with respect to the equatorial plane M-M of the tyre.

Preferably, the tyre 100 is an HP or UHP tyre for sports and/or high and ultra-high performance automobiles.

In particular, the tyre 100 carries one of the following speed codes:. "V' , "U", "H", "V", "Z","W", "Y", according to the E.T.R.T.O. standard.

In Figure 1, "a" indicates an axial direction, "c" indicates a radial direction, "M-M" indicates the equatorial plane of the tyre 100 and "R-R" indicates the rotation axis of the tyre 100.

The tyre 100 comprises a carcass structure 101 of the radial type, which in turn comprises at least one carcass ply 111.

Hereinafter, for the sake of simplicity of presentation, reference will be made to an embodiment of the tyre 100 comprising a single carcass ply 111 (mono-ply tyre). However, it is understood that what is described with reference to the carcass ply 111 is also valid for each carcass ply of tyres comprising more than one carcass ply, unless indicated to the contrary. Indeed, embodiments of the tyre 100 of the invention in which the carcass structure 101 comprises for example two carcass plies 111 (two-ply tyre) are foreseen.

The carcass ply 111 comprises a plurality of reinforcing cords 10' coated with, or incorporated in, a layer of cross-linked elastomeric material. In the case in which the tyre 100 is a two-ply tyre, the reinforcing cords of a first carcass ply can be substantially parallel to those of the other carcass ply or inclined with respect to those of the other carcass ply by an angle lower than 40°.

Preferably, the carcass ply 111 has a thread count greater than, or equal to, 70 cords/dm and lower than, or equal to, 95 cords/dm, more preferably comprised between 75 cords/dm and 90 cords/dm. For example, in a preferred embodiment of the tyre 100 of the invention, the aforementioned thread count is equal to 85 cords/dm.

Preferably, the carcass ply 111 has a thickness comprised between 0.7 mm and 1.5 mm, more preferably between 0.9 mm and 1.3 mm. For example, in the aforementioned preferred embodiment of the tyre 100 of the invention, the aforementioned thickness is equal to 1.1 mm.

The carcass ply 111 has axially opposite end edges engaged with respective annular anchoring structures 102, called bead cores, possibly associated with an elastomeric filler 104. The area of the tyre 100 comprising the bead core 102 and the possible elastomeric filler 104 forms an annular reinforcing structure 103 called "bead structure" and intended to allow the anchoring of the tyre 100 on a corresponding mounting rim, not shown.

Each annular reinforcing structure 103 is associated with the carcass structure 101 by folding back (or turning) of the opposite end edges of the at least one carcass ply 111 around the bead core 102 and the possible elastomeric filler 104, so as to form the so-called turns 101a of the carcass structure 101.

In an embodiment, the coupling between carcass structure 101 and annular reinforcing structure 103 can be made through a layer (not shown in figure 1) applied in a radially outer position with respect to the carcass ply 111.

An anti-abrasion strip 105 is arranged at each annular reinforcing structure 103 so as to wind around the annular reinforcing structure 103 along the axially inner, axially outer and radially inner areas of the annular reinforcing structure 103, thus being arranged between the latter and the rim of the wheel when the tyre 100 is mounted on the rim. Such an anti-abrasion strip 105 may however not be provided.

The tyre 100 comprises, in a radially outer position with respect to the carcass structure 101, a crossed belt structure 106 comprising at least two belt layers 106a, 106b arranged in radial juxtaposition with respect to one another.

The belt layers 106a, 106b comprise a plurality of reinforcing cords 10a, 10b, respectively. Such reinforcing cords 10a, 10b have an orientation inclined with respect to the circumferential direction of the tyre 100, or to the equatorial plane M-M of the tyre 100, by an angle comprised between 15° and 45°, preferably between 20° and 40°. For example, such an angle is equal to 30°.

The tyre 100 can also comprise a further belt layer (not shown) arranged between the carcass structure 101 and the radially innermost belt layer of the aforementioned belt layers 106a, 106b and comprising a plurality of reinforcing cords having an orientation inclined with respect to the circumferential direction of the tyre 100, or to the equatorial plane M-M of the tyre 100, by an angle equal to 90°.

The tyre 100 can also comprise a further belt layer (not shown) arranged in a radially outer position with respect to the radially outermost belt layer of the aforementioned belt layers 106a, 106b and comprising a plurality of reinforcing cords having an orientation inclined with respect to the circumferential direction of the tyre 100, or to the equatorial plane M-M of the tyre 100, by an angle comprised between 20° and 70°.

The reinforcing cords 10a, 10b of a belt layer 106a, 106b are parallel to each other and have a crossed orientation with respect to the reinforcing cords of the other belt layer 106b, 106a.

In ultra-high performance tyres, the belt structure 106 can be a turned crossed belt structure. Such a belt structure is made by arranging at least one belt layer on a support element and by turning the opposite side end edges of said at least one belt layer. Preferably, a first belt layer is initially deposited on the support element, then the support element is radially expanded, then a second belt layer is deposited on the first belt layer and finally the opposite axial end edges of the first belt layer are turned over the second belt layer to at least partially cover the second belt layer, which is the radially outermost one. In some cases, it is possible to arrange a third belt layer on the second belt layer. Advantageously, the turning of the axially opposite end edges of a belt layer over another belt layer arranged on a radially outer position with respect to the first one provide the tyre with a greater reactivity and responsiveness when cornering.

The tyre 100 comprises, in a radially outer position with respect to the crossed belt structure 106, at least one zero degrees reinforcing layer 106c, commonly known as "zero degrees belt". It comprises reinforcing cords 10c oriented in a substantially circumferential direction. Such reinforcing cords 10c thus form an angle of a few degrees (typically lower than 10°, for example comprised between 0° and 6°) with respect to the equatorial plane M-M of the tyre 100.

The reinforcing cords 10a, 10b, 10c are coated with an elastomeric material or incorporated in a matrix of cross-linked elastomeric material.

A tread band 109 made of elastomeric material is applied in a radially outer position with respect to the zero degrees reinforcing layer 106c.

Respective sidewalls 108 made of elastomeric material are also applied on the side surfaces of the carcass structure 101, in an axially outer position with respect to the carcass structure 101 itself. Each sidewall 108 extends from one of the side edges of the tread band 109 up to the respective annular reinforcing structure 103.

The anti-abrasion strip 105, if provided, extends at least up to the respective sidewall 108.

In some specific embodiments, like the one shown and described herein, the stiffness and integrity of the annular reinforcing structure 103 and of the sidewall 108 can be improved by providing a stiffening layer 108, generally known as "flipper" or additional strip-like insert.

The flipper 120 is wound around a respective bead core 102 and around the elastomeric filler 104 so as to at least partially wrap around the annular reinforcing structure 103. In particular, the flipper 120 winds around the annular reinforcing structure 103 along the axially inner, axially outer and radially inner areas of the annular reinforcing structure 103.

The flipper 120 is arranged between the turned end edge of the carcass ply 111 and the respective annular reinforcing structure 103. Usually, the flipper 120 is in contact with the carcass ply 111 and the annular reinforcing structure 103.

In some specific embodiments, like the one shown and described herein, the annular reinforcing structure 103 can also comprise a further stiffening layer 121 that is generally known by the term "chafer", or protective strip, and which has the function of increasing the stiffness and integrity of the annular reinforcing structure 103.

The chafer 121 is associated with a respective turned end edge of the carcass ply 111 in an axially outer position with respect to the respective annular reinforcing structure 103 and extends radially towards the sidewall 108 and the tread band 109.

The flipper 120 and the chafer 121 comprise reinforcing cords lOd (in figure 1 those of the flipper 1 are not visible) coated with an elastomeric material or incorporated in a matrix of cross linked elastomeric material.

The tread band 109 has, in a radially outer position thereof, a rolling surface 109a intended to come into contact with the ground. Circumferential grooves (not shown in figure 1) are formed on the rolling surface 109a, said grooves being connected by transversal notches (not shown in figure 1) so as to define on the rolling surface 109a a plurality of blocks of various shapes and sizes (not shown in figure 1).

An under-layer 107 is arranged between the crossed belt structure 106 and the tread band 109.

In some specific embodiments, like the one shown and described herein, a strip 110 consisting of elastomeric material, commonly known as "mini-sidewall", can optionally be provided in the connection area between the sidewall 108 and the tread band 109. The mini-sidewall 110 is generally obtained through co-extrusion with the tread band 109 and allow an improvement of the mechanical interaction between the tread band 109 and the sidewalls 108.

Preferably, an end portion of the sidewall 108 directly covers the side edge of the tread band 109.

In the case of tubeless tyres, like the one shown and described herein, a layer of rubber 112, generally known as "liner", is provided in a radially inner position with respect to the carcass ply 111 to provide the necessary impermeability to the inflation air of the tyre 100.

At least some of the reinforcing cords 10' (preferably all the reinforcing cords 10' of the carcass structure 111) and/or of the reinforcing cords 10a, 10b (preferably all the reinforcing cords 10a of the belt layer 106a and all the reinforcing cords 10b of the belt layer 106b, also in the case in which the belt structure 106 is a turned crossed belt structure) and/or of the reinforcing cords lOd of the flipper 120 and/or of the chafer 121 are textile reinforcing cords 10 in accordance with the present invention, of the type shown in figures 3-5 and described herein below.

On the other hand, the reinforcing cords 10c are preferably reinforcing cords of a known type comprising only multi-filament textile yarns.

Figure 2 shows an embodiment of a motorcycle tyre according to the present invention. Such a tyre is indicated with 1. In particular, it is a tyre intended to be used on the rear wheel of a Sport Touring motorcycle.

The tyre 1 comprises a radial carcass structure 2 having a central crown portion 16 including at least one carcass ply 3, described hereinafter in greater detail.

The carcass structure 2 is preferably coated on the inner walls thereof by a sealing layer 11, or so-called "liner", essentially consisting of an airtight layer of elastomeric material, adapted to provide the tyre itself, once inflated, with the hermetic seal. The carcass ply 3 has its axially opposite side edges 3a turned around respective annular reinforcing structures 4, or bead cores.

A tapered elastomeric filler 5 is applied on the outer perimeter edge of the bead cores 4. The filler 5 occupies the space defined between the carcass ply 3 and the corresponding turned side edge 3a of the carcass ply 3.

In an alternative embodiment, that is not shown, the carcass ply has the opposite side edges thereof associated without turning with particular annular reinforcing structures provided with two metallic annular inserts. In this case, a filler made of elastomeric material can be arranged in an axially outer position with respect to the first annular insert. The second annular insert, on the other hand, is arranged in an axially outer position with respect to the end of the carcass ply. Finally, is possible to provide a further filler in an axially outer position with respect to said second annular insert, and not necessarily in contact with it. This further filler ends the building of the annular reinforcing structure.

The area of the tyre comprising the bead core 4 and the filler 5 forms the so-called "bead", globally indicated in figure 2 with 15, which is intended for anchoring the tyre 1 on a corresponding mounting rim, not shown.

A belt structure 6, also described hereinafter in greater detail, is provided in a radially outer position with respect to the aforementioned carcass structure 2.

A tread band 8 is provided in a radially outer position with respect to the belt structure 6. The tyre 1 makes contact with the ground by the tread band 8.

The tyre 1 can also comprise a pair of sidewalls 2a applied laterally to the carcass structure 2 on axially opposite sides to the equatorial plane M-M thereof. The sidewalls 2a extend from the tread band 8 to the bead 15 of the tyre 1. The carcass ply 3 is preferably made of elastomeric material and comprises a plurality of reinforcing cords 10" arranged parallel to one another and perpendicular to the equatorial plane M-M.

Preferably, the belt structure 6 comprises reinforcing cords lOe which are arranged substantially parallel and side-by-side in the axial direction on the crown portion 16 of the carcass structure 2, to form a plurality of turns. Such turns are substantially oriented according to the rolling direction of the tyre 1 (in particular with an angle comprised between 0° and 5° with respect to the equatorial plane M-M), such a direction usually being called "zero degrees" or "circumferential". The aforementioned turns preferably extend over the entire crown portion 16 of the carcass structure 2.

Preferably, the belt structure 6 comprises windings of a single reinforcing cord lOe, or of a band of rubber-coated fabric comprising reinforcing cords lOe, preferably up to five, arranged side-by-side, wound in a spiral on the crown portion 16 of the carcass structure 2 from one end to the other end of the crown portion 16.

Alternatively, the belt structure 6 can comprise at least two radially juxtaposed layers, each consisting of an elastomeric material reinforced with reinforcing cords arranged parallel to one another. The layers are arranged so that the reinforcing cords of the first belt layer are oriented obliquely with respect to the equatorial plane of the tyre, whereas the reinforcing cords of the second layer also have an oblique orientation, but such an orientation is symmetrically crossed with respect to that of the reinforcing cords of the first layer, to form the so-called "crossed belt".

Preferably, the belt structure 6 comprises a support layer 9 substantially consisting of a sheet of elastomeric material arranged between the layer of reinforcing cords lOe and the carcass ply 3 and on which the aforementioned turns are wound. The layer 9 preferably extends on a surface having an axial extension substantially corresponding to the surface on which the aforementioned turns extend. Alternatively, the layer 9 can extend over a surface smaller than the surface of extension of the turns, for example only on opposite side portions of the belt structure 6.

In a further embodiment that is not shown, an additional layer of elastomeric material is arranged between the belt structure 6 and the tread band 8. Such a layer preferably extends over a surface corresponding to the surface of extension of the belt structure 6. Alternatively, the aforementioned additional layer can extend over a surface smaller than the surface of extension of the belt structure 6, for example only on opposite side portions of the belt structure 6.

The tread band 8 has a tread pattern defined by a plurality of grooves (some of which are indicated in figure 2 with 17) formed on the outer surface of the tread band 8 through a molding operation carried out concurrently with the vulcanization of the tyre 1.

At least some of the reinforcing cords 10" (preferably all the reinforcing cords 10") are textile reinforcing cords 10 in accordance with the present invention, of the type shown in figures 3-5 and described below.

On the other hand, the reinforcing cords lOe are preferably reinforcing cords of a known type comprising only multi-filament textile yarns.

With reference to figures 3-5, the reinforcing cord 10 comprises two yarns 20a, 20b twisted to one another with a predetermined twisting pitch P.

The twisting pitch P is preferably comprised between about 1 mm and about 20 mm, more preferably between about 2 mm and about 15 mm, for example equal to about 12.5 mm.

In the embodiment of figure 4, the two yarns 20a, 20b are different from one another. In particular, the yarn 20a comprises a single monofilament textile wire 21a embedded in the filaments 22a of a multifilament textile yarn 23a, whereas the yarn 20b comprises a plurality of filaments 22b of a multifilament textile yarn 23b and no monofilament textile wire. However, the yarn 20a could comprise more than one monofilament textile wire and many multifilament textile yarns. The yarn 20b could comprise many multifilament textile yarns as well.

In the embodiment of figure 5, the two yarns 20a and 20b are identical. In particular, each yarn 20a, 20b comprises a single monofilament textile wire 21a, 21b embedded in a plurality of filaments 22a, 22b of respective multifilament textile yarns 23a, 23b. However, each yarn 20a, 20b could comprise more than one monofilament textile wire and many multifilament textile yarns.

In the rest of this description reference will be made to the embodiment of figure 5. It is understood that what is described with reference to the yarn 20a of such an embodiment applies analogously to the yarn 20a of the embodiment of figure 4, while what is described with reference to the yarn 20b of the embodiment of figure 5 applies analogously to the yarn 20b of the embodiment of figure 4 except for what is stated regarding the monofilament textile wire 21b, which is not present in the yarn 20b of the embodiment of figure 4.

In any cross section of the reinforcing cord 10, the monofilament textile wire 21a, 21b is embedded in the filaments 22a, 22b of the respective yarn 20a, 20b, i.e. the filaments 22a, 22b are arranged around the respective monofilament textile wire 21a, 21b so as to completely surround the monofilament textile wire 21a, 21b, which is thus not visible from the outside since it is entirely covered by the filaments 22a, 22b of the respective yarn 20a, 20b.

Although it is particularly preferred an embodiment, like the one of figures 3-5, in which the monofilament textile wire 21a, 21b is, in any cross section of the reinforcing cord 10, completely embedded in the filaments 22a, 22b of the respective yarn 20a, 20b, other embodiments which are deemed equally preferred are those in which, in any cross section of the reinforcing cord 10, the monofilament textile wire 21a, 21b is only partially embedded in the filaments 22a, 22b of the respective yarn 20a, 20b, and in particular those in which at least 50% of the outer surface of the monofilament textile wire 21a, 21b is embedded in the filaments 22a, 22b of the respective yarn 20a, 20b.

The monofilament textile wires 21a, 21b extend along a longitudinal direction A, shown in figure 3.

The mutual arrangement of the monofilament textile wires 21a, 21b and of the filaments 22a, 22b of the respective yarns 20a, 20b along the longitudinal direction A can be such that the monofilament textile wires 21a, 21b extend substantially parallel to the filaments 22a, 22b of the respective yarn 20a, 20b, or such that the filaments 22a, 22b are wound in a helix on the respective monofilament textile wire 21a, 21b with a predetermined winding pitch that, preferably, is equal to the twisting pitch P.

In this last case, the direction of twisting of the two yarns 20a, 20b is preferably the same as that of winding of the filaments 22a, 22b on the respective monofilament textile wire 21a, 21b, but it is possible to foresee opposite directions.

The yarns 20a, 20b may or may not be twisted on themselves with respective twisting pitches that, preferably, are equal to the twisting pitch P.

The direction of twisting of the yarns 20a, 20b on themselves can be the same as or opposite to the direction of twisting of the two yarns 20a, 20b to each other.

In each of the yarns 20a, 20b the respective monofilament textile wires 21a, 21b may or may not be twisted on themselves with respective twisting pitches that, preferably, are equal to the twisting pitch P.

The direction of twisting of the monofilament textile wires 21a, 21b on themselves can be the same as or opposite to that of twisting of the two yarns 20a, 20b to each other.

The filaments 22a, 22b of the yarns 20a, 20b are made of recycled or biologically-based material, in particular recycled or biologically-based PET or nylon. For example, it is possible to use one or more of the following materials: 100% recycled PET, 30% biologically- based PET, nylon 4.10 (70% biologically-based), nylon 6.10 (100% biologically-based), nylon 56 (45% biologically-based).

The monofilament textile wires 21a, 21b are made of recycled or biologically-based material, in particular recycled or biologically-based PET or nylon. For example, it is possible to use one or more of the following materials: 100% recycled PET, nylon 6.10 (60% biologically- based), nylon 1010 (up to 99% biologically-based).

Irrespective of the specific type of textile material used for the filaments 22a, 22b, such a material is made suitably adhesive on the surface so as to offer adequate adhesion to the surrounding elastomeric material. Typically, the adhesion treatment can be carried out by coating with an adhesive substance or through a chemical or physical treatment.

For example, the adhesion treatment is carried out through immersion of the reinforcing cord 10 in a solution comprising the adhesive substance after having twisted together the two yarns 20a, 20b.

Preferably, the yarns 20a, 20b have a linear density comprised between about 400 dtex and about 4000 dtex, preferably between about 800 dtex and about 2500 dtex, depending on the structural component of the tyre 100 in which the reinforcing cords 10 are arranged.

The monofilament textile wire 21a, 21b has a diameter selected within a range of values that varies depending on the structural component in which the reinforcing cord 10 is intended to be used.

For example, in the case in which the reinforcing cord 10 is used in a carcass ply 111 and/or in the flippers 120 and/or in the chafers 121 of the tyre 100 of figure 1 or in the carcass ply 3 of the tyre 1 of figure 2, the diameter of the monofilament textile wire 21a, 21b is preferably lower than, or equal to, 0.22 mm, more preferably lower than, or equal to, 0.21 mm, even more preferably lower than, or equal to, 0.20 mm, for example equal to 0.19 mm.

Differently, in the case in which the reinforcing cord 10 is used in the belt layers 106a, 106b of the tyre 100 (or in the possible crossed belt layers of the tyre 1), the diameter of the monofilament textile wire 21a, 21b is greater than 0.22 mm, more preferably greater than, or equal to, 0.25 mm, even more preferably greater than, or equal to, 0.30 mm, for example equal to 0.30 mm or 0.40 mm.

In general, the Applicant has verified that by suitably selecting the number of yarns, the number of monofilament textile wires in each yarn (in all or only some of said yarns), the diameter of the monofilament textile wire, the linear density of the yarns and possibly the number of twists of the yarns it is possible to make reinforcing cords 10 having different mechanical behavior and therefore suitable for being used in the carcass structure 101 of the tyre 100 of figure 1 and in the carcass structure 2 of the tyre 1 of figure 2, in the crossed belt structure 106 of the tyre 100 of figure 1, and in further structural components, like for example the flippers 120 and the chafers 121 of the tyre 100 of figure 1.

In specific embodiments of the tyre 100 of figure 1, only the reinforcing cords 10', and not also the reinforcing cords 10a, 10b and lOd, or vice-versa, are reinforcing cords 10 of the type described above.

In other specific embodiments, only the reinforcing cords 10a, and not also the reinforcing cords 10', 10b and lOd, or vice-versa, are reinforcing cords 10 of the type described above. In some embodiments, only the reinforcing cords 10a and/or 10b, and not also the reinforcing cords 10' and lOd, are reinforcing cords 10 of the type described above.

In yet other embodiments, only the reinforcing cords lOd, and not also the reinforcing cords 10', 10a and/or 10b, are reinforcing cords 10 of the type described above.

When the reinforcing cords lOd are reinforcing cords 10 of the type described above, such reinforcing cords 10 can be used only in the flipper 120 (if provided and when the chafer 121 is not provided or is provided and comprises conventional reinforcing cords), only in the chafer 121 (if provided and when the flipper 120 is not provided or is provided and comprises conventional reinforcing cords), or both in the flipper 120 and in the chafer 121 (if both are provided).

Some preferred embodiments of reinforcing cords 10 in accordance with the present invention which can be used in tyres for automobiles and motorcycles are described in the following "COMPARATIVE TESTS" paragraph.

COMPARATIVE TESTS

The Applicant has made a plurality of reinforcing cords in accordance with the present invention and has subjected such reinforcing cords to comparative tests in order to compare the mechanical behavior of such reinforcing cords with that of conventional reinforcing cords made of material of fossil origin.

The result of such comparative tests is shown in figures 6-8.

Figure 6 shows the result of a comparative test performed on four samples of a first preferred embodiment of the reinforcing cord 10 shown in figures 3 and 4.

Such a reinforcing cord 10 comprised two yarns 20a, 20b twisted together, in which the yarn 20a comprised filaments 22a made of 100% recycled PET with linear density equal to 1670 dtex and a monofilament textile yarn 21a made of 100% recycled PET and having a diameter equal to 0.197 mm, whereas the yarn 20b comprised filaments 22b made of 100% recycled PET with linear density equal to 1670 dtex.

A first sample of such a reinforcing cord 10 was made by imparting 300 twists to the yarns 20a, 20b and 200 twists to the reinforcing cord 10. Such a sample is indicated here with INV 1.1.

A second sample of such a reinforcing cord 10 was made by imparting 270 twists to the yarns 20a, 20b and 220 twists to the reinforcing cord 10. Such a sample is indicated here with INV 1.2.

A third sample of such a reinforcing cord 10 was made by imparting 300 twists to the yarns 20a, 20b and 250 twists to the reinforcing cord 10. Such a sample is indicated here with INV 1.3.

A fourth sample of such a reinforcing cord 10 was made by imparting 330 twists to the yarns 20a, 20b and 280 twists to the reinforcing cord 10. Such a sample is indicated here with INV 1.4.

The four samples identified above were subjected to traction tests, so as to verify their stiffness and therefore their capability to withstand to bending stresses, like those which the carcass structures of automobile tyres are typically subjected to.

A sample of a conventional textile reinforcing cord (reference sample) typically used by the Applicant in the carcass plies, in the flippers and in the chafers of its automobile tyres was also subjected to an analogous traction test. The reference sample comprised two multifilament textile yarns twisted together, each of the two yarns comprising filaments made of PET of fossil origin with linear density equal to 1670 dtex and being without any monofilament textile wires. Such a reference sample was made by imparting 330 twists to the two yarns and 330 twists to the reinforcing cord. The reference sample is indicated here with REF.

As can be seen in figure 6, all the samples of the reinforcing cords 10 of the present invention have a mechanical behavior (in particular modulus, tenacity, breaking load, elongation at break) absolutely comparable to that of the reference sample REF, in some cases even better than the already excellent one of the reference sample, confirming the fact that the reinforcing cords 10 identified above with INV 1.1, INV 1.2, INV 1.3 and INV 1.4 are all suitable for being used in the carcass ply(-ies) and/or in the flippers and/or in the chafers of automobile tyres in place of the conventional reinforcing cords (made of material of fossil origin) currently used by the Applicant.

Figure 7 shows the result of a comparative test performed on three samples of a second preferred embodiment of the reinforcing cord 10 of the present invention.

Such a reinforcing cord 10 comprised three strands, each of which comprising two yarns 20a, 20b twisted together, each of the two yarns in turn comprising a plurality of filaments 22a, 22b and a monofilament textile wire 21a, 21b.

A first sample of such a reinforcing cord 10 was made using filaments 22a, 22b made of PET of fossil origin with linear density equal to 1670 dtex and monofilament textile wires 21a, 21b made of 100% recycled PET having a diameter equal to 0.40 mm. Such a sample is indicated here with INV 2.1.

A second sample of such a reinforcing cord 10 was made using filaments 22a, 22b made of 100% recycled PET with linear density equal to 1100 dtex and monofilament textile wires 21a, 21b made of 100% recycled PET having a diameter equal to 0.40 mm. Such a sample is indicated here with INV 2.2.

A third sample of such a reinforcing cord 10 was made using filaments 22a, 22b made of 100% PET of fossil origin with linear density equal to 1670 dtex and monofilament textile wires 21a, 21b made of 100% recycled PET with a diameter equal to 0.30 mm. Such a sample is indicated here with INV 2.3.

The three samples identified above were subjected to compression tests, so as to verify their capability to withstand to stresses like those which the belt structures of automobile tyres are typically subjected to.

Three samples of a conventional textile reinforcing cord (reference samples) typically used by the Applicant in the belt layers of its automobile tyres were subjected to an analogous compression test.

A first reference sample, indicated here with REF 1, had a construction identical to that of the sample INV 2.1 and differed from the latter only in that the monofilament textile wires were made of PET of fossil origin.

A second reference sample, indicated here with REF 2, had a construction identical to that of the sample INV 2.2 and differed from the latter only in that both the filaments of the two yarns and the monofilament textile wires were made of PET of fossil origin.

A third reference sample, indicated here with REF 3, had a construction identical to that of the sample INV 2.3 and differed from the latter only in that the monofilament textile wires were made of PET of fossil origin.

As can be seen in figure 7, the samples of the reinforcing cords 10 of the present invention all have a mechanical behavior absolutely comparable to that of the reference samples of analogous construction, in many cases even better than the already excellent one of the reference sample, confirming the fact that the reinforcing cords 10 identified above with INV 2.1, INV 2.2 and INV 2.3 are all suitable for being used in the belt layer of automobile tyres in place of the conventional reinforcing cords (made of material of fossil origin) currently used by the Applicant.

Figure 8 shows the result of a comparative test performed on a sample of a third preferred embodiment of the reinforcing cord 10 shown in figures 3 and 4.

Such a sample, indicated here with INV*, comprised two yarns 20a, 20b twisted together, in which the yarn 20a comprised a plurality of filaments 22a made of 100% recycled PET with linear density equal to 3340 dtex and a monofilament textile wire 21a made of 100% recycled PET and having a diameter equal to 0.197 mm, whereas the yarn 20b comprised a plurality of filaments 22b made of 100% recycled PET with linear density equal to 3340 dtex.

The sample INV* was subjected to a traction test, so as to verify its stiffness and therefore its capability to withstand to bending stresses, like those which the reinforcing cords used in the carcass plies of motorcycle tyres are typically subjected to.

A sample of a conventional textile reinforcing cord (reference sample) typically used by the Applicant in the carcass plies of its motorcycle tyres was also subjected to an analogous traction test. The reference sample comprised two multifilament textile yarns twisted together, each of the two yarns comprising filaments made of PET of fossil origin with linear density equal to 3340 dtex and being without any monofilament textile wires. The reference sample is indicated here with REF*.

As can be seen in figure 8, the traction curve of the sample of the reinforcing cord 10 of the present invention has a mechanical behavior (in particular modulus, tenacity and elongation at break) absolutely comparable to that of the reference sample REF*, confirming the fact that the reinforcing cord 10 identified above with INV* is suitable for being used in the carcass ply(-ies) of motorcycle tyres in place of the conventional reinforcing cords (made of material of fossil origin) currently used by the Applicant.

Of course, those skilled in the art can make further modifications and variants to the present invention described above in order to satisfy specific and contingent application requirements, these variants and modifications in any case being within the scope of protection defined by the following claims.