moldable reinforcement layer

Abstract

The present invention relates to a reinforcing ply comprising a plurality of reinforcing elements arranged side by side parallel to each other in a main direction (A) and embedded in a polymer composition, each reinforcing element comprising a first and a second filamentary member, the first filamentary member having an excessive length of A1% with respect to the stationary length of the second filamentary member at rest, where 0% < A1 < AR and AR represents the elongation at break in percent of the second filamentary member.

Description

[Technical Field]

[0001] The present invention relates to the field of reinforcing plies, in particular for vehicle tires, and to the field of vehicle tires including such plies. [Background technology]

[0002] The reinforcing ply generally consists of a plurality of reinforcing elements embedded in a matrix, such as an elastomeric matrix; these reinforcing elements can be fabric, an assembly of non-woven fibers ("nonwoven"), or a plurality of fabric or metallic threads or cords arranged side-by-side and parallel to one another.

[0003] A reinforcing ply should have sufficient strength properties to ensure its reinforcing role when incorporated into an object, such as a pneumatic tire, while at the same time offering as low resistance as possible during the manufacture of said object, such as during the construction of the pneumatic tire, in order to facilitate its manufacture. As a result of these conflicting requirements, the design of the reinforcing ply can be complex.

[0004] In the course of their research, the applicant has discovered a reinforcing ply that can be molded under very light loads while having a great ability to provide the necessary reinforcement when molded. This ply is particularly, but not exclusively, suitable for use as a carcass ply in pneumatic tires. In particular, this ply can greatly simplify the manufacturing process of pneumatic tires that include a reinforcing structure within an internal toroidal cavity, such as that described in WO 2019 / 115917. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 115917 Summary of the Invention [Means for solving the problem]

[0006] The present invention relates to at least one of the embodiments shown below. 1. A reinforcing ply comprising a plurality of reinforcing elements arranged side by side parallel to each other in the main direction (A) and embedded in a polymer composition, each reinforcing element including first and second filamentary members, the first filamentary member having an excessive length of A1% with respect to the stationary length of the second filamentary member at rest, 0% < A1 < AR, where AR represents the elongation at break in percentage units of the second filamentary member, and when any elongation rate in the main direction (A) of the ply is A1% or less, the second filamentary member is plastically deformed, and for each reinforcing element, M1 / M2 < 1, where M1 is the elastic modulus of the reinforcing element when any elongation rate of the ply is K1×A1% or less, M2 is the elastic modulus of the reinforcing element when any elongation rate of the ply is K2×A1% or more, K1 ranges from 0.8 to 0.95, K2 ranges from 1.05 to 1.2, and the elastic moduli M1, M2 and the elongation at break AR are measured in accordance with ASTM standard D885 - 03, ply. 2. For each reinforcing element, Ml / M2 is 0.5 or less, preferably 0.1 or less, preferably 0.05 or less, the ply according to Embodiment 1. 3. When any elongation rate of the ply in the main direction (A) is less than K1×A1%, each reinforcing element has an elastic modulus of 10 / A1 N or less, preferably 8 / A1 N or less, preferably 7 / A1 N or less, the ply according to Embodiment 1 or 2. 4. When any elongation rate of the ply in the main direction (A) is greater than K2×A1%, each reinforcing element has an elastic modulus of 10 N or more, preferably 15 N or more, the ply according to any one of Embodiments 1 to 3. 5. K2 ranges from 1.1 to 1.2, preferably from 1.15 to 1.2, preferably K2 = 1.2, the ply according to any one of Embodiments 1 to 4. 6. A ply according to any one of embodiments 1 to 5, wherein K1 is in the range of 0.85 to 0.95, preferably in the range of 0.9 to 0.95, preferably K1=0.95. 7. A ply according to any one of embodiments 1 to 6, wherein A1 is present in the range of from 15 to 50%, preferably in the range of from 15 to 45%, very preferably in the range of from 15 to 25%. 8. A ply according to any one of embodiments 1 to 8, wherein for each reinforcing element, the second filamentary member has an elongation before break AR of greater than or equal to 30%, preferably greater than or equal to 50%, preferably greater than or equal to 60%, preferably greater than or equal to 80%, very preferably equal to 100%, measured according to ASTM standard D885-03. 9. A ply according to any one of embodiments 1 to 8, wherein in each reinforcing element, the second filamentary members are substantially straight and the first filamentary members are wound substantially helically around the second filamentary members. 10. A ply according to embodiment 9, wherein the first filamentary members form substantially periodic loops. 11. A ply according to any one of embodiments 1 to 10, wherein the tenacity of the second filamentary members is 20 cN / tex or less, preferably 15 cN / tex or less, and more preferably 10 cN / tex or less. 12. A ply according to any one of embodiments 1 to 11, wherein the tensile strength of the first filamentary members is 30 cN / tex or more, preferably 40 cN / tex or more, and more preferably 60 cN / tex or more. 13. A ply according to any one of embodiments 1 to 12, wherein each of the first and second filamentary members does not break when the elongation of any of the plies in the main direction (A) is A1% or less. 14. A ply according to any one of embodiments 1 to 13, wherein the first filamentary member comprises at least one multifilament strand comprising a plurality of monofilaments each formed of a material selected from polyester, polyamide, polyketone, polyurethane, natural fibers and assemblies of these materials, preferably selected from polyester, polyamide, polyketone, polyurethane and assemblies of these materials, more preferably selected from assemblies of polyester and polyester. 15. A ply according to any one of embodiments 1 to 14, wherein the second filamentary members are formed of a material selected from polyesters, polyamides, polyketones and assemblies of these materials, preferably selected from polyesters, polyamides, polyketones and assemblies of these materials, more preferably made of polyamide, very preferably selected from aliphatic polyamides, very preferably selected from nylon PA4.6, PA6, PA6.6 and PA6.10. 16. A ply according to any one of embodiments 1 to 15, wherein the second filamentary member comprises at least one monofilament, preferably two monofilaments. 17. A ply according to any one of embodiments 1 to 15, wherein the second filamentary member comprises at least one multifilament strand comprising a plurality of monofilaments. 18. A ply according to any one of embodiments 1 to 17, wherein the reinforcing element also includes means for joining the first and second filamentary members together. 19. A ply according to embodiment 18, wherein the joining means is a connecting thread wound substantially helically around the first and second filamentary members. 20. A ply according to embodiment 19, in which the joining means is formed of a material selected from polyesters, polyamides, polyketones and assemblies of these materials, preferably selected from polyesters, polyamides, polyketones and assemblies of these materials, more preferably made of polyamide, very preferably selected from nylon, in particular aliphatic polyamides such as nylon PA4.6, PA6, PA6.6 or PA6.10. 21. A ply according to any one of embodiments 1 to 20, wherein the polymer composition comprises at least one elastomer selected from diene-based elastomers, olefin-based elastomers, thermoplastic elastomers, and mixtures thereof. 22. The ply according to embodiment 21, wherein the polymer composition comprises an elastomer selected from the group consisting of synthetic polyisoprene (IR), natural rubber (NR), isoprene copolymers, and mixtures thereof. 23. A ply according to any one of embodiments 1 to 22, wherein the polymer composition comprises a reinforcing filler selected from carbon black, silica, and mixtures thereof. 24. A reinforcing ply for a pneumatic vehicle tire according to any one of embodiments 1 to 23, wherein the laying pitch p of the reinforcing elements in a direction (X) perpendicular to the direction (A) is in the range of 0.5 to 1.5 mm, preferably in the range of 0.7 to 1.5 mm, and wherein the direction (A) is substantially parallel to the axial direction (YY') of the pneumatic tire. 25. A reinforcing ply according to embodiment 24, in which the wireless D / (pD) is in the range of 0.6 to 4.5, preferably in the range of 0.8 to 4.2, and D represents the diameter of the reinforcing element. 26. A reinforcing ply according to any of embodiments 24 and 25, wherein the average thickness of the ply is 3 mm or less, preferably 3 mm or less, and more preferably 1.5 mm or less. 27. A rubber article comprising a ply according to any one of embodiments 1 to 26. 28. A pneumatic or non-pneumatic vehicle tire comprising a ply according to any one of embodiments 1 to 26. 29. A pneumatic vehicle tire intended to be mounted on a rim, the pneumatic vehicle tire having, in an inflated mounted state, an axial width S and a radial height H, a radially outer tread surface intended to contact the ground, a crown having two axial ends each extending radially inward by a sidewall portion and then by a bead portion intended to contact the rim, and at least one carcass reinforcement extending from the bead portion through the sidewall portion to the crown, the crown, sidewall portion and bead portion defining an internal annular cavity, the reinforcement being fixed to the two bead portions, and the carcass reinforcement being a ply according to any one of embodiments 1 to 26. 30. A pneumatic tire according to embodiment 29, comprising a reinforcing structure (7) including two reinforcing elements (8), each reinforcing element (8) extending continuously within the annular internal cavity (6) from a crown interface (81) connected to the radially inner surface of the crown (23) to a bead interface (82) connected to the axially inner surface of the bead portion (41), the reinforcing structure (7) being distributed circumferentially around the entire circumference of the tire, the crown interface (81) being positioned at an axial distance A from an equatorial plane (XZ) passing through the center of its tread surface (21) and perpendicular to the axis of rotation (YY') that is at most equal to 0.45 times the axial width S, and the bead interface (82) being positioned at a radial distance B from the radially innermost point (I) of the axially inner surface of the bead portion (41) that is at least equal to 0.10 times the radial height H and at most equal to 0.5 times the radial height H. 31. A method for manufacturing a pneumatic tire according to one of embodiments 27 to 29, comprising: A sleeve is constructed by successively laying the various elements constituting the sleeve around a tire building drum that exhibits substantial rotational symmetry about its axis of rotation, the sleeve comprising at least i. Two bead portions intended to contact the rim and positioned approximately equidistant in the axial direction from the equatorial plane (XZ) of the green configuration, and two sidewall portions each extending axially inward from the bead portions; ii. a carcass reinforcement located radially inward, connecting the two sidewall portions to one another and fixed in each bead portion at circumferential reinforcing elements, and made up of a reinforcing ply according to the invention; widening the inner annular space by radially outwardly moving at least a portion of the sleeve located between the sidewall portions, the portion intended to form the crown portion of the green configuration, a crown including a radially outer tread surface intended to come into contact with the ground and a crown reinforcement intended to reinforce the crown of a pneumatic tire, the crown including two axial ends of each sidewall portion extending toward the bead portion after being laid on the sleeve; 32. The method according to embodiment 31, wherein the inner annular space is expanded by pressurizing the inner annular space using an inflation gas. 33. A method according to embodiment 30 or 31, wherein the green form includes a reinforcing structure including two reinforcing elements, the reinforcing structure being connected on one side to the radially inner surface of the crown by a crown interface and on the other side to the bead portion by an axially inner bead interface, the reinforcing structure being circumferentially distributed around the entire circumference of the pneumatic tire. [Brief explanation of the drawings]

[0007] [Figure 1] 1 shows a pneumatic tire according to the present invention; [Figure 2] FIG. 1 is a schematic diagram of a sleeve and crown under construction. [Figure 3] FIG. 10 is a diagram showing a schematic view of the annular inner space (6) being enlarged by molding a sleeve. [Figure 4] 2 to 4 show diagrammatically a pneumatic tire manufactured using the method according to the invention, the general implementation of which is shown in sequence. DETAILED DESCRIPTION OF THE INVENTION

[0008] definition In the following text, by convention, the circumferential direction XX', the axial direction YY', and the radial direction ZZ' mean the direction tangential to the tire tread surface in the tire rotational direction, the direction parallel to the tire rotational axis, and the direction perpendicular to the tire rotational axis, respectively. "Radially inner" and "radially outer" mean "the side closer to the tire rotational axis" and "the side farther from the tire rotational axis", respectively. "Axially inner" and "axially outer" mean "the side closer to the tire equatorial plane" and "the side farther from the tire equatorial plane", respectively, and the tire equatorial plane XZ is a plane that passes through the center of the tire tread surface and is perpendicular to the tire rotational axis.

[0009] "Substantially parallel" or "extending substantially along" means that the angle formed by the two directions in question is less than 10°, preferably less than 5°, more preferably less than 2°, and most preferably no more than the error in measuring the angle by the preferred method.

[0010] The "general direction" of an object means the general direction in which the object extends along its greatest length. In the case of a fabric, the general direction of the fabric is parallel to the longitudinal edges of the fabric. Thus, for example, a fabric wound on a reel rotating about an axis has a general direction that is substantially parallel to the winding direction of the fabric (i.e., the circumferential direction), which is perpendicular to the axial and radial directions of the reel.

[0011] Any numerical range expressed as "between a and b" refers to a numerical range greater than a and less than b (i.e., excluding the endpoints a and b), whereas a numerical range expressed as "from a to b" refers to a numerical range from the endpoint a to the endpoint b (i.e., including the exact endpoints a and b).

[0012] The expression "element based on ~" means an element that includes a mixture of various components or materials used and / or the product of an in-situ reaction, and some of these components or materials can react with each other at least partially during various manufacturing stages of the element and / or are intended to react.

[0013] The carbon-containing compounds referred to in this specification can be of fossil or biobased origin. In the latter case, they are partially or completely derived from biomass or obtained from renewable starting materials derived from biomass. These are, inter alia, polymers, plasticizers, fillers, etc.

[0014] Reinforcement ply The reinforcing ply according to the present invention includes a plurality of reinforcing elements arranged side by side parallel to each other in the main direction (A) and embedded in a polymer composition. Each reinforcing element includes a first and a second filamentous member. The first filamentous member has an excessive length of A1% with respect to the stationary length of the second filamentous member at rest, where 0% < A1 < AR, and AR represents the elongation at break in percentage units of the second filamentous member. When the elongation rate in any direction in the main direction (A) of the ply is A1% or less, the second filamentous member is plastically deformed, and for each reinforcing element, M1 / M2 < 1, where M1 is the elastic modulus of the reinforcing element when the elongation rate of any part of the ply is K1×A1% or less, and M2 is the elastic modulus of the reinforcing element when the elongation rate of any part of the ply is K2×A1% or more. K1 ranges from 0.8 to 0.95, and K2 ranges from 1.05 to 1.2. The elastic moduli M1, M2, and the elongation at break AR are measured in accordance with ASTM standard D885-03.

[0015] Thus, the reinforcing ply according to the invention has a moderate resistance to elongation when the elongation of any of the plies in the main direction (A) is less than A1% and the reinforcing elements have an elastic modulus M1, and a greater resistance when the elongation of any of the plies in the main direction (A) is higher than A1% due to the higher elastic modulus M2 than M1. Therefore, when incorporating this ply into an object, it is easy to adapt the design of the ply according to the desired shape by substantially aligning the main direction (A) with the deformation direction of the object incorporating the ply.

[0016] Preferably, M1 / M2 is equal to or less than 0.5, more preferably equal to or less than 0.1, and most preferably equal to or less than 0.05. This ratio represents the difference in the behavior of the plies in terms of elongation resistance in the main direction (A). The smaller this ratio, the greater the elongation resistance at elongations above A1% compared to elongations below A1%.

[0017] The values ​​of the elastic moduli M1 and M2, the number of reinforcements and the laying density of the reinforcements, expressed as the number of threads per dm measured in the plane of the ply and perpendicular to the main direction (A), will be adapted by the skilled person depending on the specific requirements of the ply, in particular through the appropriate selection of the constituent materials of the reinforcing elements.

[0018] Preferably, when the elongation of any of the plies in the main direction (A) is less than K1 x A1%, each reinforcing element has a modulus of elasticity of 10 / A1 N or less, preferably 8 / A1 N or less, preferably 7 / A1 N or less. For example, and just as an example of calculation, if A1 = 20, and the elongation of the plies in the main direction (A) is less than K1 x 20%, each reinforcing element has a modulus of elasticity of 10 / 20 N or less, preferably 8 / 20 N or less, more preferably 7 / 20 N or less. Therefore, the force required to elongate the plies in the main direction (A) to an elongation of K1 x A1% is relatively small.

[0019] Preferably, when the elongation rate of any ply in the main direction (A) is greater than K2×A1%, each reinforcing element has a modulus of elasticity of 10 N or more, preferably 15 N or more. Thus, the ply exhibits a significantly greater elongation resistance when any elongation rate exceeds K2×A1%. Very preferably, each reinforcing element has a modulus of elasticity of 25 N or less, preferably 20 N or less.

[0020] The coefficients K1 and K2 represent a transition zone in which the modulus of elasticity of the reinforcing element lies between M1 and M2. K2 is preferably in the range from 1.1 to 1.2, more preferably in the range from 1.15 to 1.2, and preferably K2 = 1.2. K1 is preferably in the range from 0.85 to 0.95, more preferably in the range from 0.9 to 0.95, and preferably K1 = 0.95.

[0021] First filamentary member Each reinforcing element of the reinforcing ply according to the present invention includes first and second filamentary members, and the first filamentary member has an excessive length of A1% with respect to the stationary length of the second filamentary member at rest, where 0% < A1 < AR, and AR represents the elongation at break in percentage units of the second filamentary member and is measured in accordance with ASTM standard D885 - 03. The excessive length of A1% means that the first filamentary member has a length equal to (100 + A1)% of the stationary length of the second filamentary member at rest.

[0022] Preferably, the first filamentary member comprises at least one multifilament strand including a plurality of monofilaments each formed of a material selected from polyester, polyamide, polyketone, polyurethane, natural fibers, and assemblies of these materials, preferably selected from polyester, polyamide, polyketone, polyurethane, and assemblies of these materials, and more preferably selected from assemblies of polyester and polyester. Polyester is advantageous because of its high tensile strength, low cost, thermal integrity making it suitable for use in pneumatic tires, and standard heat shrink options.

[0023] The first filamentary elements have an excess length of A1% at rest relative to the rest length of the second filamentary elements. Preferably, A1 lies within the range of 15 to 50%, preferably 15 to 45%, and most preferably 15 to 25%. Thus, when the ply is stretched in the main direction (A), the second filamentary elements plastically deform while the first filamentary elements expand due to their excess length. When the ply reaches an elongation of A1%, the first filamentary elements are fully expanded and contribute more fully to the ply's elongation resistance in the main direction (A).

[0024] The rest length of the first filamentary member is measured in the main direction of the first filamentary member and corresponds to the overall length of the first filamentary member when it is not incorporated into a reinforcing element and is at rest, i.e., not stretched or compressed in the general direction of the first filamentary member, and therefore exhibits zero elongation.

[0025] The tensile strength of the first filamentary members is preferably 30 cN / tex or greater, preferably less than 40 cN / tex, and more preferably less than 60 cN / tex, as determined in accordance with ASTM standard D885-03.

[0026] Second filamentous member The second filamentary members of each reinforcing element of the reinforcing ply according to the invention are such that they are plastically deformed when the elongation of the ply in the main direction (A) is less than or equal to A1%.

[0027] Preferably, when the elongation of any of the plies in the main direction (A) is A1% or less, each of the first and second filamentary members will not break.

[0028] Preferably, the elongation at break of the second filamentary members is sufficient to maintain the integrity of the reinforcing ply during elongation. Preferably, for each reinforcing element, the second filamentary members have an elongation before break AR of 30% or more, preferably 50% or more, preferably 60% or more, preferably 80% or more, very preferably 100% or more, 150% or more, very preferably 200% or more.

[0029] The elongation at break of the second filamentary members is measured within the reinforcing element (ie, when assembled in the reinforcing element) according to ASTM standard D885-03.

[0030] The tensile strength of the second filamentary members is preferably 20 cN / tex or less, more preferably 15 cN / tex or less, and more preferably 10 cN / tex or less. The tensile strength of the second filamentary members is determined in accordance with ASTM standard D885-03. The low tensile strength associated with the plastic nature of the second filamentary members allows them to plastically deform very easily under low stress without breaking, thus providing the reinforcing ply according to the present invention with the ability to stretch uniformly, homogeneously, and without jerking in the general direction (A) without elastic return during molding steps carried out during the manufacture of an article, such as a pneumatic tire, incorporating the ply, thereby significantly reducing the risk of obtaining an out-of-spec article before curing.

[0031] The second filamentary members are preferably made of a material selected from polyesters, polyamides, polyketones and assemblies of these materials, preferably selected from polyesters, polyamides, polyketones and assemblies of these materials, more preferably made of polyamides, and very preferably selected from nylons, in particular aliphatic polyamides such as nylon PA4.6, PA6, PA6.6 or PA6.10. Nylon filamentary members have the advantage of having a relatively high elongation at break and a lower tensile strength than commonly used materials such as rayon.

[0032] In each reinforcing element, the second filamentary members are preferably substantially straight and the first filamentary members are preferably wound substantially helically around the second filamentary members. Thus, when the reinforcing element is deformed in its main direction (A), the second filamentary members stretch while plastically deforming, while the first filamentary members expand. Thus, in one configuration, the reinforcing element is of the wound type.

[0033] A second filamentary member particularly suited to the needs of the present invention is, for example, a nylon thread having a count of 20 to 30 tex and a breaking strength of 200 to 250 cN, such as the commercially available thread "Webflex HEN" from Coats.

[0034] Preferably, the first filamentary members are helically wound around the second filamentary members to form substantially periodic loops, with the second filamentary members being substantially straight. In one preferred configuration, the reinforcing element is of the loop type.

[0035] Loop-type reinforcing elements ("loop yarn" or "boucle yarn") are well known to those skilled in the art. They differ from wrap-type elements (or "gimp yarn") in that a first filamentary member, commonly known as a "covering thread" or "effect thread," is supplied in excess during the manufacture of the element. Loop-type reinforcing elements can be manufactured using conventional methods, such as ring-type screw machines, which allows for the employment of a second filamentary member with lower tensile strength than that of the fragile core machine-type methods of manufacturing wrap-type elements.

[0036] Thus, the use of loop-type reinforcing elements allows the ply according to the invention to employ second filamentary members that deform plastically under low stress, thereby allowing for easy, uniform and homogeneous deformation of the ply according to the invention during the forming operation.

[0037] In one preferred configuration, the second filamentary member comprises at least one monofilament, preferably two monofilaments. In another preferred configuration, the second filamentary member comprises at least one multifilament strand comprising a plurality of monofilaments.

[0038] The reinforcing element may also comprise means for joining the first and second filamentary members together, preferably a connecting thread wound substantially helically around the first and second filamentary members to join them together, and the connecting means, e.g. the connecting thread, is preferably made of a material selected from polyesters, polyamides, polyketones and assemblies of these materials, preferably selected from polyesters, polyamides, polyketones and assemblies of these materials, more preferably made of polyamide, very preferably selected from nylon, in particular aliphatic polyamides such as nylon PA4.6, PA6, PA6.6 or PA6.10.

[0039] polymer composition A reinforcing ply according to the present invention comprises a plurality of reinforcing elements embedded in a polymeric composition.

[0040] The term "embedded" means that each reinforcing element is surrounded by the polymer composition.

[0041] In one embodiment, the polymer composition comprises at least one elastomer selected from diene-based elastomers, olefin-based elastomers, thermoplastic elastomers, and mixtures thereof. Diene-type elastomers or rubbers (these terms are synonymous) are generally elastomers (i.e., homopolymers or copolymers) derived at least in part from diene monomers (monomers having two conjugated or non-conjugated carbon-carbon double bonds). The composition can then be in an uncured or cured state.

[0042] The diene elastomer of the rubber composition is particularly preferably selected from the group comprising polybutadiene (BR), synthetic polyisoprene (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers, and even more preferably such copolymers are selected from the group comprising butadiene / styrene copolymers (SBR), isoprene / butadiene copolymers (BIR), isoprene / styrene copolymers (SIR), isoprene / butadiene / styrene copolymers (SBIR) and mixtures of such copolymers.

[0043] Each polymer composition may contain only one diene elastomer or a mixture of diene elastomers, and these diene elastomer(s) may be used in combination with any type of synthetic elastomer other than diene elastomers, or with polymers other than elastomers, such as thermoplastic polymers.

[0044] Furthermore, in this embodiment, each polymer composition, in addition to the elastomer, which is preferably a diene elastomer, also comprises a reinforcing filler, such as carbon black, silica or mixtures thereof, a crosslinking system, such as a vulcanization system, and various additives.

[0045] In another embodiment, each polymer composition comprises at least one thermoplastic polymer. By definition, a thermoplastic polymer is hot-meltable. Examples of such thermoplastic polymers are aliphatic polyamides, such as nylon, polyesters, such as PET or PEN, and thermoplastic elastomers.

[0046] Thermoplastic elastomers (abbreviated as "TPEs") are elastomers that come in the form of block copolymers based on thermoplastic blocks. They have a structure intermediate between thermoplastic polymers and elastomers and are formed in known manner from hard thermoplastic, particularly polystyrene, sequences connected by soft elastomeric sequences, such as polybutadiene or polyisoprene sequences for unsaturated TPEs or poly(ethylene / butylene) sequences for saturated TPEs. Therefore, in known manner, such TPE block copolymers are generally characterized by the presence of two glass transition peaks: a first peak (lower, generally negative temperature) associated with the elastomeric sequences of the TPE copolymer, and a second peak (higher positive temperature, usually above 80 °C for preferred elastomers of the TPS type) associated with the thermoplastic (e.g., styrene block) portion of the TPE copolymer. These TPE elastomers are often triblock elastomers, with two hard segments connected by a soft segment. The hard and soft segments can be arranged linearly or in a star-branched or branched configuration. TPE elastomers can also be diblock elastomers, in which a single rigid segment is connected to a soft segment. Typically, each of these segments or blocks contains at least five, and typically more than ten, base units (e.g., styrene and isoprene units for a styrene / isoprene / styrene block copolymer).

[0047] Preferably, the thermoplastic elastomer is unsaturated. By definition and in a known manner, an unsaturated TPE elastomer means a TPE elastomer that has ethylenic unsaturation, i.e., contains (conjugated or non-conjugated) carbon-carbon double bonds, and conversely, is "saturated". Naturally, a TPE elastomer is a TPE elastomer that does not have such double bonds.

[0048] The reinforcing ply according to the invention is particularly suitable for use in pneumatic or non-pneumatic tires. Preferably, with regard to the constraints specific to tires intended to support a vehicle, a reinforcing ply for a pneumatic vehicle tire, i.e. a reinforcing ply that can be used in a vehicle tire, has a laying pitch p of the reinforcing elements in a direction (X) perpendicular to the direction (A) ranging from 0.5 to 1.5 mm, preferably from 0.7 to 1.5 mm, and in a direction (X) substantially parallel to the axial direction (YY') of the pneumatic tire. This laying pitch allows sufficient reinforcement against the stresses to which the pneumatic tire is subjected.

[0049] Preferably, in reinforcing plies suitable for use in pneumatic tires, the ratio D / (pD) is in the range of 0.6 to 4.5, preferably in the range of 0.8 to 4.2, where D represents the diameter of the reinforcing element. When this ratio is respected, the size of the rubber bridge, i.e. the rubber located between two consecutive reinforcing elements, is particularly suitable for use in pneumatic tires.

[0050] Preferably, reinforcing plies suitable for use in pneumatic tires have an average thickness of not more than 3 mm, preferably not more than 2 mm, preferably not more than 1.5 mm, in order to limit the overall thickness of the tire and therefore, inter alia, the rolling resistance of the pneumatic tire.

[0051] Finished or semi-finished products and tires The subject of the present invention is also a finished or semi-finished product comprising a reinforcing ply according to the invention. The finished or semi-finished product can be any article comprising a reinforcing ply. Non-limiting examples that may be mentioned include conveyor belts and pneumatic or non-pneumatic tires.

[0052] A pneumatic vehicle tire intended to be mounted on a rim has, in an inflated mounted state, an axial width S and a radial height H, and includes a crown having a radially outer tread surface intended to contact the ground and two axial ends each extending radially inward by a sidewall portion and then by a bead portion intended to contact the rim. The crown, sidewall portion and bead portion define an internal annular cavity. The pneumatic tire includes at least one carcass reinforcement extending from the bead portion through the sidewall portion to the crown, this reinforcement being fixed to the two bead portions. A pneumatic tire according to the invention is characterized in that the carcass reinforcement is a ply according to the invention.

[0053] Preferably, and with reference to Figure 1 used for non-limiting illustration, a pneumatic tire (1) according to the invention, intended to be mounted on a rim (5), comprises a crown (2) having a radially outer tread surface (21) intended to come into contact with the ground and two axial ends (22) each extending radially inward by a sidewall portion (3) and then by a bead portion (4) intended to come into contact with the rim (5). The crown, sidewall portions and bead portions define an internal annular cavity (6). The pneumatic tire (1) comprises at least one carcass ply made of the reinforcing ply according to the invention, and a reinforcing structure (7) comprising two reinforcing elements (8) each extending continuously within the annular internal cavity (6) from a crown interface (81) connected to the radially inner surface of the crown (23) to a bead interface (82) connected to the axially inner surface of the bead portion (41), the reinforcing structure (7) being distributed circumferentially around the entire circumference of the tire, the crown interface (81) being located at an axial distance A from an equatorial plane (XZ) passing through the center of the tread surface (21) of the tire and perpendicular to the axis of rotation (YY') that is at most equal to 0.45 times the axial width S, and the bead interface (82) being located at a radial distance B from the radially innermost point (I) of the axially inner surface of the bead portion (41) that is at least equal to 0.10 times the radial height H and at most equal to 0.5 times the radial height H.

[0054] The principle of the pneumatic tire according to this variant of the invention is to incorporate into a conventional tire a reinforcing structure intended to increase the overall stiffness of the tire, this stiffness having a structural component called structural stiffness provided by the reinforcing structure of the tire and a tire component called tire stiffness provided by the pressure of the inflation gas, the reinforcing structure contributing to the tire stiffness.

[0055] Method for manufacturing a tire according to the present invention Unvulcanized tires, commonly known as "green forms," ​​are generally manufactured from drums by following the known steps of flat manufacturing on a first drum, building on a second drum, and then finishing. In the final vulcanization step, the unvulcanized plastic material becomes elastic, among other things, due to the vulcanization. During the building step, the inner annular space of the pneumatic tire is generally formed by expanding the green form of the pneumatic tire assembled on the drum or by deforming this green form with the aid of a membrane or deformable wall.

[0056] In the following text, for non-limiting purposes, reference is made to Figures 1 to 4 in which like elements are provided with the same reference numerals.

[0057] Another subject of the invention is a method for manufacturing a pneumatic tire according to the invention, comprising: - constructing a sleeve (15) by successively laying the various elements that make up the sleeve around a tire building drum that exhibits substantial rotational symmetry about its axis of rotation, said sleeve (15) comprising at least - two bead portions (4) intended to contact the rim and positioned approximately equidistant in the axial direction from the equatorial plane (XZ) of the green configuration, and two sidewall portions (3) each extending axially inward from the bead portions (4); - a carcass reinforcement (9) located radially inside, connecting the two sidewall portions (3) to one another and fixed in each bead portion (4) at circumferential reinforcing elements (11), and made up of a reinforcing ply according to the invention, - optionally a rubber layer (13) ("inner liner") located radially inside the carcass reinforcement and airtight to inflation gases; - widening the inner annular space (6) by radially outwardly displacing at least the portion (16) of the sleeve located between the sidewalls, which is intended to form the crown portion of the green configuration, - laying radially outward of the green form a crown (2) including a radially outer tread surface (21) intended to come into contact with the ground, and a crown reinforcement (10) intended to reinforce the crown of a pneumatic tire, the crown (2) including two axial ends (22) of each sidewall portion (3) extending towards the bead portion (4) after being laid on the sleeve.

[0058] The equatorial plane (XZ) is the plane perpendicular to the axis of rotation of the tire or green form and passing through the center of its tread surface. Green form is understood to be the pneumatic tire in its uncured state, i.e., before the composition that constitutes it has been crosslinked.

[0059] The inner annular space (6) is preferably expanded by pressurizing the inner annular space using inflation gas.

[0060] The green form includes a reinforcing structure (7) including two reinforcing elements (8), which are connected on one side to the radially inner surface of the crown by a crown interface (81) and on the other side to the bead portion by an axially inner bead interface (82), the reinforcing structure being preferably distributed circumferentially around the entire circumference of the pneumatic tire (1).

[0061] Thus, when the inner annular space (6) is expanded, each of the two elements (8) of the reinforcing structure (7) extends continuously within the annular internal cavity from the crown interface to the bead interface.

[0062] The reinforcing ply according to the invention is particularly suitable for the construction of pneumatic tires containing structures within the toroidal interior space. In particular, if the length L1 between the attachment points on the inner surface of the tire of this structure is smaller than the length L2 between the attachment points measured along said inner surface, it would be impossible to build such a tire by carrying out flat construction as is commonly practiced. The extensibility of the reinforcing ply according to the invention, used as a crown ply and designed so that A1 is substantially equal to (L2 / L1-1) x 100, allows the different elements in green form to be laid flat.

[0063] Measurement method The modulus of elasticity and elongation at break of the reinforcing elements are measured according to ASTM standard D885-003.

Claims

1. A reinforcing ply comprising a plurality of loop-type reinforcing elements arranged side by side in parallel with each other in a main direction (A) and embedded in a polymer composition, each reinforcing element including first and second filamentary members, the first filamentary member having an overlength of A1% with respect to the rest length of the second filamentary member at rest, 0% < A1 < AR, where AR represents the elongation at break in percentage units of the second filamentary member, when any elongation rate in the main direction (A) of the ply is A1% or less, the second filamentary member is plastically deformed, and for each reinforcing element, M1 / M2 < 1, where M1 is the modulus of the reinforcing element when any elongation rate of the ply is K1×A1% or less, M2 is the modulus of the reinforcing element when any elongation rate of the ply is K2×A1% or more, K1 ranges from 0.8 to 0.95, K2 ranges from 1.05 to 1.2, and the moduli M1, M2 and the elongation at break AR are measured according to ASTM standard D885-03. A ply characterized by the above.

2. For each reinforcing element, M1 / M2 is 0.5 or less, preferably 0.1 or less, and preferably 0.05 or less. The ply according to Claim 1.

3. When any elongation rate of the ply in the main direction (A) is less than K1×A1%, each reinforcing element has a modulus of 10 / A1 N or less, preferably 8 / A1 N or less, and preferably 7 / A1 N or less. The ply according to Claim 1 or 2.

4. When any elongation rate of the ply in the main direction (A) is greater than K2×A1%, each reinforcing element has a modulus of 10 N or more, preferably 15 N or more. The ply according to any one of Claims 1 to 3.

5. A1 exists within the range of 15 to 50%, preferably within the range of 15 to 45%, and very preferably within the range of 15 to 25%. The ply according to any one of Claims 1 to 4.

6. For each reinforcing element, the second filamentary member has an elongation at pre-break AR of 30% or more, preferably 50% or more, preferably 60% or more, preferably 80% or more, and very preferably equal to 100%, measured according to ASTM standard D885-03. The ply according to any one of claims 1 to 5.

7. The tensile strength of the second filamentary member is 20 cN / tex or less, preferably 15 cN / tex or less, and more preferably 10 cN / tex or less. The ply according to any one of claims 1 to 6.

8. The tensile strength of the first filamentary member is 30 cN / tex or more, preferably 40 cN / tex or more, and more preferably 60 cN / tex or more. The ply according to any one of claims 1 to 7.

9. The laying pitch p of the reinforcing element in the direction (X) perpendicular to the direction (A) is in the range from 0.5 to 1.5 mm, preferably in the range from 0.7 to 1.5 mm, and the direction (A) is substantially parallel to the axial direction (YY') of the pneumatic tire. The reinforcing ply for a pneumatic vehicle tire according to any one of claims 1 to 8.

10. Including the ply according to any one of claims 1 to 9. A pneumatic or non-pneumatic vehicle tire, characterized in that.

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