Multi-composite reinforcement based on glass-resin composite

Abstract

The invention relates to a multi-composite reinforcement (R1, R2) comprising at least one single strand (10) of a glass-resin composite having glass filaments (101) embedded in a cross-linked resin (102), the at least one single strand (10) being covered with a layer of a thermoplastic material (12), the thermoplastic material (12) being based on a thermoplastic elastomer comprising at least one polyether-type elastomer block and at least one non-styrenic-type thermoplastic block. Figure 2

Description

Title of the invention: Multi-composite reinforcement based on a glass-resin composite. TECHNICAL FIELD OF THE INVENTION

[0001] The field of the present invention is that of composite reinforcements and multilayer laminates usable in particular for the reinforcement of semi-finished products or finished articles in rubber such as tires for vehicles, of pneumatic or non-pneumatic type.

[0002] It relates more particularly to composite reinforcements based on monostrands of the "CVR" type (abbreviated for Composite Glass-Resin) with high mechanical and thermal properties, comprising multifilament glass fibers embedded in a cross-linked resin and usable in particular as reinforcement elements of these bandages. STATE OF THE ART

[0003] Bandage designers have long been searching for textile or composite "reinforcements" (longitudinal reinforcing elements) of low density, which can advantageously and effectively replace conventional wires or metal cables, in order to reduce the weight of these bandages and also to overcome any corrosion problems.

[0004] Thus, document EP 1,167,080 (or US 7,032,637) has long described CVR monostrands with very high mechanical properties, comprising continuous, unidirectional glass fibers impregnated in a thermosetting polyester resin matrix, in particular vinylester. It has been demonstrated that, thanks to these very high properties, it is advantageous to substitute such CVR monostrands for steel cables as reinforcements for pneumatic tires, thereby significantly lightening the structure of these tires.

[0005] More recently, documents WO 2015 / 014578 and WO 2015 / 014579 described CVR single strands with even improved physical and mechanical properties, obtained through a specific production process.

[0006] Finally, documents WO 2015 / 090973, WO 2015 / 165777, WO 2016 / 116457, WO 2016 / 189209 and WO 2016 / 189126 also described multi-composite reinforcements based on such CVR monostrands, this time with a layer of a thermoplastic material, in particular polyester, individually covering each monostrand or collectively covering a bundle of several monostrands. This layer of thermoplastic material has been shown, thanks in particular to a supposed compression-fitting effect, to give these composite reinforcements properties in compression, bending or under transverse shear which have been significantly improved, particularly at high temperature, compared to those of previously known CVR single strands.

[0007] Experience shows, however, that these multi-composite materials or reinforcements based on single-strand CVR can be further improved, particularly when used in bandages designed to bear heavy loads. Indeed, the greater the load supported, the stronger the reinforcing element must be while also being able to deform to ensure significant impact resistance.

[0008] Thus, manufacturers are constantly seeking solutions to improve the strength of the reinforcing elements in multi-composite reinforcements based on single-strand CVR and therefore to improve the impact resistance of these reinforcements. BRIEF DESCRIPTION OF THE INVENTION

[0009] Continuing its research, the Applicant unexpectedly discovered that substituting thermoplastic with a specific thermoplastic elastomer makes it possible to further improve CVR monostrands with regard to the aforementioned problem.

[0010] Thus the invention relates to a multi-composite reinforcement (RI, R2) comprising at least one monostrand (10) of glass-resin composite comprising glass filaments (101) embedded in a crosslinked resin (102), the at least one monostrand (10) being covered with a layer of a thermoplastic material (12), characterized in that the thermoplastic material (12) is based on a thermoplastic elastomer comprising at least one polyether type elastomer block and at least one non-styrenic type thermoplastic block.

[0011] The invention also relates to a multilayer laminate comprising this reinforcement, arranged between and in contact with two layers, at least one of which is a layer of rubber composition, in particular diene, and / or at least one layer of thermoplastic. It also relates to an article comprising this reinforcement or this laminate, in particular a tire for a vehicle, preferably a non-pneumatic tire.

[0012] The multi-composite reinforcement can be used as a reinforcement element in top reinforcements (or belts) or in carcass reinforcements of pneumatic tires, as described in particular in the aforementioned documents.

[0013] The multi-composite reinforcement of the invention is also advantageously usable, due to its low density and its improved compression, bending and transverse shear properties, as a reinforcement element in non-pneumatic type flexible tires or wheels, i.e. structurally supported (without internal pressure). Such tires or wheels are well known to those skilled in the art (see, for example, EP 1 242 254 or US 6,769,465, EP 1 359 028 or US 6,994,135, EP 1 242 254 or US 6,769,465, US 7,201,194, WO 00 / 37269 or US 6,640,859, WO 2007 / 085414, WO 2008 / 080535, WO 2009 / 033620, WO 2009 / 135561, WO 2012 / 032000); when they are associated with any mechanical element These rigid reinforcements, designed to ensure the connection between the flexible tire and the wheel hub, replace the assembly consisting of the tire, rim, and disc as found on most current road vehicles. The multi-composite reinforcement of the invention is particularly advantageous in the annular shear layers (or "shear layers") that form the belt of such tires.

[0014] The bandages of the invention, in particular, can be intended for motor vehicles, without any particular limitation.

[0015] The invention and its advantages will be readily understood in the light of the detailed description and embodiments that follow, as well as Figures 1 to 8 relating to these embodiments, which schematically illustrate (without regard to a specific scale). BRIEF DESCRIPTION OF THE FIGURES

[0016] [Fig.1] In cross-section, a single strand (10) in CVR usable in a multi-composite reinforcement according to the invention.

[0017] [Fig.2] In cross-section, two examples (Rl and R-2) of multi-composite reinforcements according to the invention (Fig. 2a and Fig. 2b).

[0018] [Fig.3] In cross-section, another example (R-3) of multi-composite reinforcement according to the invention.

[0019] [Fig.4] In cross-section, another example (R-4) of multi-composite reinforcement according to the invention.

[0020] [Fig.5] In cross-section, another example (R-5) of multi-composite reinforcement according to the invention.

[0021] [Fig.6] In cross-section, another example (R-6) of multi-composite reinforcement according to the invention.

[0022] [Fig.7] In cross-section, an example (20) of a multilayer laminate according to the invention comprising a multi-composite reinforcement according to the invention (R-7) itself embedded in a diene rubber matrix.

[0023] [Fig.8] A device usable for manufacturing a single strand (10) in CVR usable as a basic constituent element of a multi-composite reinforcement according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] In the present, the expression "composition based on" means a composition comprising the mixture and / or the in situ reaction product of the different constituents used, some of these constituents being able to react and / or being intended to react with each other, at least partially, during the different phases of manufacturing the composition; the composition can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0025] By "elastomer matrix" is meant all the elastomers in the composition, including the thermoplastic elastomers defined below.

[0026] Unless otherwise indicated, the rates of units resulting from the insertion of a monomer into a copolymer are expressed as a molar percentage relative to the total monomer units of the copolymer.

[0027] The expression "part by weight per hundred parts by weight of elastomer" (or pce) is to be understood in the context of the present invention as the part, by mass per hundred parts of elastomer present in the rubber composition considered and constituting a layer.

[0028] In this document, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0029] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​from greater than a to less than b (i.e., excluding the bounds a and b), while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​from a to b (i.e., including the strict bounds a and b). In the present case, when an interval of values ​​is designated by the expression "from a to b", the interval represented by the expression "between a and b" is also and preferably designated.

[0030] The compounds mentioned in the description may be of fossil origin or bio-based. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. Similarly, the compounds mentioned may also come from the recycling of materials already in use, that is to say, they may be partially or totally derived from a recycling process, or obtained from raw materials themselves derived from a recycling process. This includes, in particular, polymers, plasticizers, fillers, etc.

[0031] The invention therefore relates to a multi-composite reinforcement, in other words a composite of composites, usable in particular for the reinforcement of rubber articles such as vehicle tires, which has as its essential characteristic of comprising at least, first of all, one or more single strands (10) of glass-resin composite (abbreviated "VRC") as schematically shown in Figures 1 and 2, comprising glass filaments (101) embedded in a crosslinked resin (102), the at least one single strand (10) being covered with a layer of a thermoplastic material (12), the thermoplastic material (12) being based on a thermoplastic elastomer comprising at least one polyether type elastomer block and at least one non-styrenic type thermoplastic block.

[0032] Typically, glass filaments are present in the form of a single multifilament fiber or several associated multifilament fibers between them. In the latter case, the multifilament fibers are preferably essentially unidirectional. Each multifilament fiber can comprise several dozen, hundreds, or even thousands of individual glass filaments. These very fine individual filaments generally and preferably have an average diameter in the range of 5 to 30 µm, more preferably 10 to 20 µm. The cross-section of the individual filaments can be, for example, cylindrical, oval, square, or rectangular.

[0033] By way of example of glass fibers usable within the framework of the present invention, one may cite Owens Corning's "R25H" or "SE1200" glass fibers, Nippon Electric Glass's "AR320S-920S", "AR640S-920S", or "AR1200S-920S" alkali-resistant glass fibers, or Owens Corning's "Cem-fil". Those skilled in the art are well aware of how to adapt the sizing to the surface of the filaments to improve the compatibility of the filaments with the resin used in the glass-resin composite, particularly with the help of a silane-type compatibilizing agent.

[0034] By “crosslinked resin”, it is understood that the resin is hardened (photocured and / or thermocured), in other words in the form of a network of three-dimensional bonds, in a state proper to so-called thermosetting polymers (as opposed to so-called thermoplastic polymers).

[0035] The crosslinked resin is advantageously based on a resin composition comprising at least a photocrosslinkable resin and a crosslinking system comprising a photoinitiator agent.

[0036] By "resin composition" is meant the resin as such or any composition based on this resin and comprising at least one additive (i.e. one or more additives) before crosslinking.

[0037] The crosslinkable resin used is by definition a crosslinkable (i.e., hardenable) resin capable of being crosslinked (hardened) by any known method, in particular and preferably by UV (or UV-visible) radiation.

[0038] Preferably, the crosslinking resin is a photocurable resin selected from the group consisting of vinyl ester, epoxy, polyester, novolac resins and mixtures thereof, preferably from the group consisting of vinyl ester, epoxy resins and mixtures thereof, and preferably again from the group consisting of vinyl ester resins and mixtures thereof. As is known to those skilled in the art, these photocurable resins may contain a diluent, such as styrene, in a concentration of up to approximately 40% by weight of the photocurable resin. Commercially available photocurable resins are often sold diluted.

[0039] The term "polyester" resin is commonly understood to mean an unsaturated polyester resin. "Vinylester" resins, on the other hand, are well known in the field of composite materials.

[0040] Without this definition being limiting, the vinyl ester resin is preferably of the epoxy vinyl ester type. More preferably, a vinyl ester resin, in particular of the epoxy type, is used which is at least partly based on (i.e. grafted onto a structure of the type) novolac (also called phenoplast) and / or bisphenolic, or preferably a vinyl ester resin based on novolac, bisphenolic, or novolac and bisphenolic.

[0041] A novolac-based epoxyvinylester resin (part in brackets in formula I below) corresponds, for example, in a known manner, to the following formula (I):

[0042] A bisphenol A-based epoxyvinylester resin (part in brackets of formula (II) below) corresponds, for example, to formula (II) (the "A" indicating that the product is manufactured using acetone): fl (II)

[0043] A novolac- and bisphenolic-type epoxyvinylester resin has shown excellent results. Examples of such a resin include the vinyl ester resins "ATLAC 590" and "ATLAC E-Nova FW 2045" from AOC (diluted with approximately 40% styrene) described in applications EP 1 074 369 and EP 1 174 250. Epoxyvinylester resins are available from other manufacturers such as, for example, AOC (USA - "VIPEL" resins).

[0044] The proportion of crosslinkable resin, preferably photocurable, in the resin composition may be in the range of more than 93% to 99.5% by weight, preferably more than 94.5% to 99% by weight, and preferably more than 96% to 99% by weight, relative to the total weight of the resin composition. When the (photo)curable resin includes a diluent, the aforementioned proportions of (photo)curable resin include said diluent.

[0045] Preferably, the crosslinking system of the resin composition comprises a UV-sensitive (reactive) photoinitiator above 300 nm, preferably between 300 and 450 nm. This photoinitiator is used at a preferential rate of 0.5% to 3% by weight. more preferably from 1% to 2.5% by weight, preferably from 1% to 2% by weight, relative to the total weight of the resin composition.

[0046] For the purposes of the invention, particularly when the photocurable resin is chosen from the group consisting of vinyl ester, epoxy, polyester, novolac resins and mixtures thereof, the photoinitiator is preferably chosen from the group consisting of type I photoinitiators and mixtures thereof. The photoinitiator may also be a photoinitiator that is not a type I photoinitiator, for example a type II or other photoinitiator, but this is not preferred.

[0047] Type I photoinitiators are selected from the group consisting of benzoin ethers, benzyl ketals, alpha-dialkoxyacetophenones, alpha-hydrodyalkylphenones, alpha-aminoalkylphenones, phosphine oxides, and mixtures thereof. Preferably, the photoinitiating agent is selected from the group consisting of phosphine oxides and mixtures thereof. The phosphine oxide may advantageously be a bis(acyl)phosphine oxide.

[0048] By way of example of a photoinitiating agent usable within the scope of the present invention, one may mention bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (“Omnirad 819” from IGM or “speedcureBPO” from Lambson) or a mono(acyl)phosphine oxide (for example, “Esacure TPO” from IGM), such phosphine compounds being able to be used in mixture with other photoinitiators, for example, alpha-hydroxy-ketone type photoinitiators such as dimethylhydroxy-acetophenone (e.g., “Omnirad 1173” from IGM) or 1-hydroxy-cyclohexyl-phenyl-ketone (e.g., “Omnirad 184” from IGM), benzophenones such as 2,4,6-trimethylbenzophenone (e.g., “Esacure TZT” from IGM) and / or thioxanthone derivatives such as isopropylthioxanthone (e.g., "Esacure Omnirad ITX" from IGM).

[0049] The resin crosslinking system may also include a crosslinking agent other than the photoinitiator, for example at a rate of between 0% and 30% by weight, preferably from 1% to 15% by weight, preferably from 5% to 15% by weight, relative to the total weight of the resin composition. Alternatively, the resin composition may not include any crosslinking agent other than the photoinitiator.

[0050] As an example of a crosslinking agent other than the photoinitiator, we can cite the multifunctional acrylate or methacrylate derivatives well known to those skilled in the art.

[0051] The crosslinking agent, other than the photoinitiator, may be chosen from the group consisting of multifunctional (meth)acrylates and mixtures thereof, preferably from the group consisting of tri(meth)acrylates and mixtures thereof. In particular, The crosslinking agent can be chosen from the group consisting of the triacrylate family.

[0052] The glass filaments (101) advantageously represent 60% to 85%, preferably 65% ​​to 80%, by weight of the single strand (10) of fiber-resin composite. The crosslinked resin (102) advantageously represents 15% to 40%, preferably 20% to 35%, by weight, of the single strand (10) of fiber-resin composite.

[0053] The weight percentage of the filaments is calculated by dividing the initial fiber count by the final monofilament count. The count (or linear density) is determined on at least three samples, each corresponding to a length of 50 m, by weighing this length; the count is given in tex (weight in grams of 1000 m of product – as a reminder, 0.111 tex is equivalent to 1 denier). The percentage by weight of crosslinked resin can be obtained by calculating the difference between the final monofilament count and the initial fiber count.

[0054] Furthermore, the volume fraction of glass fiber (101) in the CVR monostrand (10) is advantageously within a range of 40% to 75%, preferably from 45% to 55%. The volume fraction of crosslinked resin (102) in the CVR monostrand (10) is advantageously within a range of 35% to 60%, preferably from 45% to 55%.

[0055] The volume fractions of glass fiber and crosslinked resin in the final CVR monostrand (10) correspond respectively to the surface fraction of glass fiber or crosslinked resin in a cross-section of the CVR monostrand relative to its total cross-sectional area. The surface fractions of glass fiber and crosslinked resin can be determined by any method that allows for the measurement of surfaces. For example, the volume fractions can be determined according to the following protocol: - we take a single-strand CVR cross-linked wire, - it is coated with a cold coating resin, of the epoxy type, in a vacuum coating machine (CitoVac from the company Stuers), -the single-strand CVR is cut using a hydraulic guillotine (SH-5214 from Baileigh) - The section of the single-strand CVR is polished using a mechanical polisher from the company Mecapol to a final grit of 0.25 µm, - a deposit of 1 to 4 nm of gold is made using a gold metallizer (Cerssington series 108 or 208 from the Eloïse company), - The cross-section of the single strand in CVR is observed using a scanning electron microscope under vacuum (15kV), and - Using an image processing program, such as FIJI, we calculate the surface percentage of glass filaments or crosslinked resin (%fibers of glass = area of ​​glass fibers / (area of ​​glass fibers + area of ​​crosslinked resin) * 100) and (%resin = area of ​​crosslinked resin / (area of ​​glass fibers + area of ​​crosslinked resin) * 100).

[0056] Preferably, in each single strand (10) in CVR or, if there are several, in all or at least part (preferably the majority) of the single strands (10) in CVR, the alignment rate of the glass filaments is such that more than 85% (% by number) of the filaments have an inclination with respect to the axis of the single strand that is less than 2.0 degrees, more preferably less than 1.5 degrees, this inclination (or misalignment) being measured as described in the publication "Critical compressive stress for continuon fiber unidirectional composites" by Thompson et al, Journal of Composite Materials, 46 (26), 3231-3245.

[0057] The single strand (10) in glass-resin composite advantageously has an average diameter DM within a range of 0.2 to 1.3 mm, preferably from 0.25 to 1.3 mm, preferably from 0.3 to 1.2 mm.

[0058] The average diameter DM covers both monostrands of essentially cylindrical shape (with a circular cross-section) and monostrands of different shapes, for example, oblong monostrands (with a more or less flattened shape, oval for example) or with a square or rectangular cross-section. The average diameter DM is advantageously defined as follows: DM = a / (S / j), where S is the cross-sectional area of ​​the glass-resin composite monostrand (10). To determine the average diameter DM, at least 5 measurements are taken at different locations on the monostrand.

[0059] The glass transition temperature (Tg) of the crosslinked resin can be greater than 170°C, for example from 175°C to 190°C. Advantageously, the Tg of the crosslinked resin is preferably greater than 190°C, preferably greater than 195°C, in particular greater than 200°C. It is measured in a known manner by DSC (Differential Scanning Calorimetry) on the second pass, for example and unless otherwise specified in this application, according to ASTM D3418 of 1999 (Mettler Toledo "822-2" DSC apparatus; nitrogen atmosphere; samples preheated from room temperature (23°C) to 250°C (10°C / min), then rapidly cooled to 23°C, before final recording of the DSC curve from 23°C to 250°C, according to a ramp of 10°C / min).

[0060] Preferably, in the multi-composite reinforcement of the invention, the single strand (10) of CVR or, if there are several, all or at least part (preferably the majority) of the single strands (10) of CVR has a density (or specific gravity in g / cm3) which is between 1.7 and 2.3, for example between 1.8 and 2.1. It is measured (at 23°C) using a specialized balance from Mettler Toledo of the "PG503 DeltaRange" type; the samples, a few cm in size, are successively weighed in air and immersed in ethanol; the device's software then determines the average density over three measurements.

[0061] According to another essential feature of the invention, as already indicated, a layer of a thermoplastic material (12) covers the single strand (10) in CVR or, if there are several, individually each single strand or collectively all or at least part (preferably the majority) of the single strands, to constitute the multi-composite reinforcement of the invention.

[0062] It has been observed that the presence of this sheath (thermoplastic material layer (12)) confers upon the CVR monostrands, and therefore upon the multi-composite reinforcement of the invention, significantly improved compression, flexural, and transverse shear (perpendicular to the axis of the monostrand) endurance properties, particularly at high temperatures, compared to those of prior art CVR monostrands. This improvement is further enhanced by the use of a thermoplastic elastomer comprising at least one polyether-type elastomer block and at least one non-styrenic-type thermoplastic block as the thermoplastic material (12).

[0063] In general, thermoplastic elastomers (abbreviated as "TPE") have an intermediate structure between thermoplastic polymers and elastomers. They are block copolymers, consisting of rigid, thermoplastic blocks linked by flexible, elastomer blocks.

[0064] For the purposes of the invention, said thermoplastic elastomer is a block copolymer comprising at least one polyether type elastomer block and at least one non-styrenic type thermoplastic block (NPST). In what follows, when a polyether block is referred to, it is therefore an elastomeric block predominantly (i.e., more than 50% by weight, preferably more than 80% by weight) composed of a polymer resulting from the polymerization of ether-type monomers, and, when a non-styrenic block is referred to, it is a block predominantly (i.e., more than 50% by weight, preferably more than 80% by weight) composed of a polymer resulting from the polymerization of monomers other than styrenic compounds (i.e., other than styrene and substituted and / or functionalized styrenes).

[0065] Preferably, the melting temperature (Tf) of the thermoplastic elastomer is in the range of 120°C to 195°C. Advantageously, the Tf of the thermoplastic elastomer is in the range of 130°C to 180°C, preferably from 135°C to 170°C. The melting temperature is measured in a known manner by Differential Scanning Calorimetry (DSC) according to ASTM D3418 (1999).

[0066] It can be noted that the Tf of the thermoplastic elastomer corresponds to the Tf of the thermoplastic blocks of the thermoplastic elastomer.

[0067] The number-average molecular weight (Mn) of the thermoplastic elastomer is preferably between 30,000 and 500,000 g / mol, preferably between 40,000 and 400,000 g / mol. Even more preferably, the Mn of the thermoplastic elastomer is in the range of 50,000 to 300,000 g / mol, and better still, of 60,000 to 150,000 g / mol.

[0068] The number-average molecular weight (Mn) of the thermoplastic elastomer is determined in a known manner by size-exclusion chromatography (SEC). For example, in the case of styrenic thermoplastic elastomers, the sample is first solubilized in tetrahydrofuran at a concentration of approximately 1 g / L; then the solution is filtered through a 0.45 µm pore size filter before injection. The apparatus used is a WATERS alliance chromatographic system. The elution solvent is tetrahydrofuran, the flow rate is 0.7 mL / min, the system temperature is 35°C, and the analysis time is 90 min. A set of four WATERS columns in series, with the trade names "STYRAGEL" ("HMW7", "HMW6E", and two "HT6E"), is used. The injected volume of the polymer sample solution is 100 µL.The detector is a WATERS 2410 differential refractometer, and its associated software for processing chromatographic data is the WATERS MILLENIUM system. The calculated average molar masses are relative to a calibration curve established with polystyrene standards. The conditions are adaptable by those skilled in the art. The value of the polydispersity index Ip (reminder: Ip = Mw / Mn, where Mw is the weight-average molecular mass and Mn is the number-average molecular mass) of the thermoplastic elastomer is preferably less than 3; more preferably less than 2; and even more preferably less than 1.5.

[0069] The thermoplastic elastomer can be in a linear form. For example, the thermoplastic elastomer is a diblock copolymer: polyether block / TPNS block. The thermoplastic elastomer can also be a triblock copolymer: polyether block / TPNS block / polyether block, that is, a central elastomer block and two terminal thermoplastic blocks, one at each end of the elastomer block. Similarly, the multiblock thermoplastic elastomer can be a linear sequence of polyether elastomer blocks and non-styrenic thermoplastic blocks.

[0070] Alternatively, the thermoplastic elastomer useful for the purposes of the invention may be in a star shape with at least three points. For example, the thermoplastic elastomer may then consist of a star-shaped polyether elastomer block with at least three points and a TPNS thermoplastic block located at the end of each of the points of the polyether elastomer block. The number of points of the central elastomer may vary, for example, from 3 to 12, and preferably from 3 to 6.

[0071] Alternatively, the thermoplastic elastomer may be in a branched or dendrimer form. The thermoplastic elastomer may then consist of a branched polyether or dendrimer elastomer block and a TPNS thermoplastic block, located at the end of the branches of the dendrimer elastomer block.

[0072] Preferably, the thermoplastic elastomer is in linear and multiblock form.

[0073] The volume fraction of polyether elastomer block in the thermoplastic elastomer is in the range of 1% to 95%, preferably from 10% to 92%, more preferably from 30% to 90%. Preferably, it is in the range of 40% to 85%, preferably from 50% to 80%.

[0074] The volume fraction of TPNS block in the thermoplastic elastomer is in the range of 5% to 99%, preferably from 8% to 90%, more preferably from 10% to 70%. Preferably, it is in the range of 15% to 60%, preferably from 20% to 50%.

[0075] The elastomer blocks of the thermoplastic elastomer for the purposes of the invention can be any polyether type elastomers known to those skilled in the art.

[0076] These polyether type elastomer blocks preferably have a Tg (glass transition temperature) measured by DSC according to ASTM D3418 of 1999, less than 25°C, preferably having a Tg within a range of -110°C to 25°C, preferably from -70°C to 20°C and more particularly from -50°C to 0°C.

[0077] The polyether elastomer blocks of the thermoplastic elastomer can be composed of monomers selected from cyclic alcohols or ethers, preferably aliphatic cyclic alcohols or ethers, such as, for example, ethanol or tetrahydrofuran. Preferably, the polyether elastomer block(s) of the thermoplastic elastomer are selected from the group consisting of polytetramethylene glycol (PTMG), polyethylene glycols (PEG), polypropylene ether glycol (PPG), polyhexamethylene ether glycol, polytrimethylene ether glycol (PO3G), poly(3-alkyltetrahydrofurans), and mixtures thereof. Preferably, the polyether elastomer block(s) of the thermoplastic elastomer are chosen from the group consisting of polytetramethylene glycols (PTMG), polyethylene glycols (PEG) and their mixtures.

[0078] The elastomeric blocks may further comprise polyester blocks. Examples of polyesters include polyethylene terephthalate, polybutene terephthalate, and polyethylene-2,6-naphthalate, as well as polybutylene succinate and polyethylene adipate. These blocks advantageously exhibit a Tg measured by DSC according to ASTM D3418:2015, below 90°C, preferably between -70°C and 20°C, and more particularly between -50°C and 0°C.

[0079] Advantageously, the elastomeric blocks of the thermoplastic elastomer have, in total, an average number molecular mass ("Mn") ranging from 25,000 g / mol to 350,000 g / mol, preferably from 35,000 g / mol to 250,000 g / mol so as to give the thermoplastic elastomer good elastomeric properties and sufficient mechanical strength compatible with use in the rubber article according to the invention.

[0080] The polyether elastomer block can also be made up of several polyether elastomer blocks as defined above.

[0081] The thermoplastic blocks of the thermoplastic elastomer are non-styrenic blocks, that is to say preferably thermoplastics resulting from the polymerization of any suitable monomer and not comprising styrenic monomers or less than 5%.

[0082] Preferably, the thermoplastic blocks of the thermoplastic elastomer are chosen from the group consisting of polyamides, polyesters and their mixtures, preferably the non-styrenic thermoplastic block(s) of the thermoplastic elastomer are chosen from the group consisting of polyamides.

[0083] Most preferably, the thermoplastic blocks of the thermoplastic elastomer are chosen from the group consisting of the polyamides PA6, PAU, PA12, PA4.12, PA4.14, PA4.18, PA6.10, PA6.12, PA6.14, PA6.18, PA9.12, PA10.10, PA10.12, PA10.14, PA10.18 and their mixtures, preferably the thermoplastic blocks of the thermoplastic elastomer are chosen from the group consisting of the polyamides PA6, PAU, PA12 and their mixtures.

[0084] Particular thermoplastic elastomers in which the non-styrenic thermoplastic blocks are polyamides are usually denoted TPE-A or TPA (thermoplastic copolyamide) or PEBA (block amide copolyether), and they are particularly preferred for the purposes of the invention. Advantageously, the thermoplastic elastomer is chosen from the group consisting of polyether and polyamide block copolymers (PEBA).

[0085] According to the invention, the thermoplastic blocks of the thermoplastic elastomer have, in total, an average number molecular mass ("Mn") ranging from 5,000 g / mol to 150,000 g / mol, so as to give the thermoplastic elastomer good elastomeric properties and sufficient mechanical strength compatible with use in the rubber article according to the invention.

[0086] The thermoplastic block can also be made up of several thermoplastic blocks as defined above.

[0087] Examples of commercially available thermoplastic elastomers include PEBA elastomers of the "PEBAX" type, marketed by Arkema, for example under the name "PEBAX 4033", "PEBAX 6333”, “PEBAX 35R53”, “PEBAX 55R53” or even the “VESTAMID E” marketed by EVONIK, for example under the name “VESTAMID E55” or “VESTAMID E62”. We can also mention the polyether / polyester elastomers (COPE), marketed by the company Envalior under the name “Arnitel® ECO L460”.

[0088] In the thermoplastic material (12), the proportion of the polyether and TPNS block TPE elastomer (i.e., the TPE elastomer(s)) is preferably in the range of 50 to 100 parts per cent, preferably from 80 to 100 parts per cent. Preferably, the thermoplastic elastomer constitutes 100% of the elastomer matrix of the thermoplastic material (12), i.e., its proportion is 100 parts per cent.

[0089] The thermoplastic material (12) may optionally include all or part of the usual additives normally used in elastomer compositions for bandage reinforcement elements, such as fillers, crosslinking agents, plasticizers (such as plasticizing oils and / or plasticizing resins), pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents, adhesion promoters, reinforcing resins (such as described for example in application WO 02 / 10269).

[0090] Advantageously, the thermoplastic material (12) comprises a single thermoplastic material.

[0091] Fig. 2 schematically shows, in cross-section, two examples (R1 and R-2) of multi-composite reinforcements according to the invention, in which a single monostrand (10) of CVR as described above, for example of diameter DM equal to 1 mm, has been covered by its layer, sheath of thermoplastic material (12), for example PEBA, of minimum thickness denoted Em (for example equal to about 0.2 mm); in these two examples, the cross-section of the multi-composite reinforcement is either rectangular (here essentially square) or circular (respectively Fig. 2a and Fig. 2b).

[0092] Preferably, the minimum thickness (denoted Em) as schematically shown for example in [Fig.2], of the layer of thermoplastic material covering the monostrand (10) or each monostrand (10) if there are several (measured "on the back" of each monostrand), is between 0.05 and 0.5 mm, preferably between 0.1 and 0.4 mm, in particular between 0.1 and 0.3 mm.

[0093] The diameter (for Fig. 2a) or the thickness (for Fig. 2b) noted DR of these reinforcements Rl and R-2 of the invention, equal to DM+2 Em, is therefore about 1.4 mm in these two examples.

[0094] Thanks to the combined presence of its glass filaments (101), its crosslinked resin (102) and the thermoplastic sheath (12) fulfilling a function of the single-strand (10) in CVR, the multi-composite reinforcement of the invention (Rl, R-2) is characterized by a high shear deformation capacity, high dimensional, mechanical and thermal stability and improved impact resistance.

[0095] In the case where several CVR monostrands are used, the thermoplastic layer or sheath can be deposited individually on each of the monostrands as illustrated for example in Figures 2, 5 and 6, or deposited collectively on several of the monostrands arranged appropriately, for example aligned along a main direction, as illustrated for example in Figures 3, 4 and 7.

[0096] Figure 3 schematically shows, in cross-section, another example of a multi-composite reinforcement (R-3) in which two single strands of CVR (10), of substantially the same diameter (for example, approximately 1 mm), have been covered together with a sheath of thermoplastic material (12), for example, PEBA, of minimum thickness Em (for example, approximately 0.25 mm). In these examples, the cross-section of the multi-composite reinforcement is rectangular, with a thickness DR equal to DM + 2 Em, i.e., for example, approximately 1.5 mm.

[0097] Fig. 4 schematically shows, in cross-section, another example of a multi-composite reinforcement (R-4) in which four single strands of CVR (10), substantially of the same diameter (for example equal to about 0.5 mm) have been covered with a sheath of thermoplastic material, for example PEBA, to constitute a multi-composite reinforcement of substantially square cross-section, of thickness DR.

[0098] The thermoplastic and therefore thermofusible nature of the material (12) covering each strand (10) in CVR allows, very advantageously, the manufacture by thermal bonding of a wide variety of multi-strand, multi-composite reinforcements with different shapes and cross-sections. This is achieved by at least partial melting of the covering material, followed by cooling of all the strands (10) sheathed in thermoplastic material (12) once they have been arranged together in an appropriate configuration. This at least partial melting will preferably be carried out at a temperature between the melting temperature Tf of the thermoplastic material (12) and the glass transition temperature of the cross-linked resin (102).

[0099] Fig. 5 schematically represents, in cross-section, another example of a multi-composite reinforcement (R-5) according to the invention in which two elementary multi-composite reinforcements R-2 as schematically represented in Fig. 2 (Fig. 2b) have been brought into contact, glued, welded together by surface melting of their thermoplastic sheath (12) and then cooled to obtain this R-5 reinforcement of thickness DR.

[0100] [Fig.6] reproduces another example of a multi-composite reinforcement according to the invention in which three elementary multi-composite site reinforcements R-2 as schematically shown in [Fig.2] (Fig. 2b) have been aligned, brought into contact, then glued, welded together by surface melting of their thermoplastic sheath and then cooling, to obtain another multi-composite reinforcement (R-6) of straight section of thickness DR.

[0101] The invention also relates to a laminate comprising at least one multi-composite reinforcement according to the invention as described above, disposed between and in contact with two layers, of which at least one layer is a rubber composition, in particular dienic, and / or at least one thermoplastic layer.

[0102] In this application, the following definitions are commonly understood: - "laminate" or "multilayer laminate", in the sense of the international patent classification: any product comprising at least two layers, whether planar or not, which are in contact with each other, the latter being able to be bonded or connected to each other; the expression "bonded" or "connected" should be interpreted broadly so as to include all means of bonding or assembly, in particular by gluing; - "Dienic rubber": any elastomer (alone elastomer or mixture of elastomers) which is derived, at least in part (i.e., a homopolymer or a copolymer), from diene monomers, that is to say, monomers bearing two carbon-carbon double bonds, whether these are conjugated or not,

[0103] - "thermoplastic": a material which softens under the action of heat and hardens upon cooling in a reversible manner.

[0104] Fig. 7 represents an example of such a multilayer laminate (20) comprising a multi-composite reinforcement (R-7), consisting of three single strands of CVR (10a, 10b, 10c) (as schematically shown in Fig. 1) collectively embedded in their thermoplastic sheath (12), this reinforcement according to the invention R-7 being itself encased by a sheath (14) of elastomer, for example dienic, to constitute a multilayer laminate according to the invention.

[0105] This lightweight and high-performance multilayer laminate, which is insensitive to corrosion, makes it possible to advantageously replace conventional rubber plies reinforced with steel cables or conventional textile cords in vehicle tires.

[0106] It also advantageously allows the design of non-pneumatic bandages in which the annular shear layer(s) forming the belt of such bandages include this laminate.

[0107] Thanks also to the presence of a significant amount of thermoplastic material, this laminate of the invention has the advantage of being low hysteresis compared to such conventional fabrics. Now, a major objective of The goal of pneumatic tire manufacturers is precisely to lower the hysteresis of their constituents in order to reduce the rolling resistance of these tires.

[0108] Each layer of rubber composition, or hereafter "rubber layer", constituting the multilayer laminate of the invention is based on at least one elastomer, preferably of the diene type.

[0109] The diene elastomer is preferably chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), various butadiene copolymers, various isoprene copolymers, and mixtures of these elastomers, such copolymers being in particular chosen from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR) and isoprene-butadiene-styrene copolymers (SBIR).

[0110] The diene elastomer may be an "isoprene" elastomer, that is, a homopolymer or copolymer of isoprene, in other words, a diene elastomer selected from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), various isoprene copolymers, and mixtures of these elastomers. The isoprene elastomer is preferably natural rubber or a synthetic polyisoprene of the cis-1,4 type. Among these synthetic polyisoprenes, polyisoprenes with a cis-1,4 linkage percentage (molar %) greater than 90% are preferably used, and more preferably greater than 98%. According to a preferred embodiment, each layer of the rubber composition comprises 50 to 100 parts per cent of natural rubber. The diene elastomer may also be made up, in whole or in part, of another diene elastomer such as, for example, an SBR elastomer used in cutting or not with another elastomer, for example of the BR type.

[0111] The diene elastomer can also be a thermoplastic elastomer. A thermoplastic elastomer (TPE) is understood to be a polymer with a structure intermediate between a thermoplastic polymer and an elastomer. A thermoplastic elastomer consists of one or more rigid "thermoplastic" segments connected to one or more flexible "elastomer" segments. Thus, the thermoplastic elastomer(s) comprise at least one elastomer block and at least one thermoplastic block. When the diene elastomer of the sheath (14) is a thermoplastic elastomer, this thermoplastic elastomer is different from the thermoplastic elastomer of the thermoplastic material (12).

[0112] Advantageously, a rubber composition layer of the rubber layer comprises more than 50% by mass of non-thermoplastic diene elastomer.

[0113] The rubber composition of the rubber layer may contain one or more diene elastomer(s), the latter being able to be used in association with any type of synthetic elastomer other than diene, or even with polymers other than elastomers.The rubber composition may also include all or some of the additives usually used in rubber matrices for the manufacture of tires, such as, for example, reinforcing fillers like carbon black or silica, coupling agents, anti-aging agents, antioxidants, plasticizers or extending oils, whether the latter are aromatic or non-aromatic, high glass transition temperature plasticizing resins, processing agents, tackifying resins, anti-reversion agents, methylene acceptors and donors, reinforcing resins, a crosslinking or vulcanizing system.

[0114] Preferably, the crosslinking system of the rubber composition is a so-called vulcanization system, i.e., based on sulfur (or a sulfur-donating agent) and a primary vulcanization accelerator. Various known secondary accelerators or vulcanization activators may be added to this basic vulcanization system. Sulfur is used at a preferential rate of between 0.5 and 10 parts per million (ppm), and the primary vulcanization accelerator, for example a sulfenamide, is used at a preferential rate of between 0.5 and 10 ppm. The reinforcing filler content, for example carbon black or silica, is preferably greater than 50 ppm, in particular between 50 and 150 ppm.

[0115] All carbon blacks are suitable, particularly those of the HAF, ISAF, and SAF types conventionally used in tires (so-called tire-grade blacks). Among these, carbon blacks of ASTM grade 300, 600, or 700 (e.g., N326, N330, N347, N375, N683, N772) are particularly suitable. Precipitated or fumed silicas with a BET surface area of ​​less than 450 m² / g, preferably from 30 to 400 m² / g, are particularly suitable as silicas.

[0116] A person skilled in the art will be able, in light of this description, to adjust the formulation of the rubber composition in order to achieve the desired levels of properties (in particular modulus of elasticity), and to adapt the formulation to the specific application envisaged.

[0117] Preferably, the rubber composition, in its crosslinked state, has a tensile secant modulus at 10% elongation of between 4 and 25 MPa, more preferably between 4 and 20 MPa; values ​​in particular between 5 and 15 MPa have proven particularly suitable for reinforcing tire belts. The modulus measurements are carried out in tension, Unless otherwise indicated according to ASTM D 412 of 1998 (specimen "C"): the "true" secant modulus (i.e., reduced to the actual cross-section of the specimen) at 10% elongation, noted here as Ms and expressed in MPa (normal temperature and humidity conditions according to ASTM D 1349 of 1999), is measured in the second elongation (i.e. after one accommodation cycle).

[0118] Each layer of thermoplastic composition, or hereinafter "thermoplastic layer", constituting the multilayer laminate of the invention is based on at least one thermoplastic.

[0119] The thermoplastic can be selected from the group consisting of polyethylenes (PE), polyvinyl chlorides (PVC), polyethylene terephthalate (PET), polypropylenes (PP), polystyrenes (PS), polyamides (PA), polyetherimides (PEI), polyetherketoneketones (PEKK), polyetheretherketones (PEEK), polycarbonates (PC), polyphthalamides (PPA), polyoxymethylenes (POM) and their mixtures.

[0120] The multi-composite reinforcement according to the invention can be disposed between and in contact with a layer of rubber composition comprising more than 50% by mass of non-thermoplastic diene elastomer and a layer of composition comprising more than 50% by mass of thermoplastic and / or thermoplastic elastomer.

[0121] Advantageously, in the multilayer laminate (30) of the invention, the thermoplastic layer (12) is provided with an adhesive layer with respect to each layer of rubber or thermoplastic composition with which it is in contact.

[0122] To make the rubber or thermoplastic adhere to the thermoplastic material (12), any suitable adhesive system may be used, for example a simple textile glue of the "RFL" (resorcinol-formaldehyde-latex) type comprising at least one diene elastomer such as natural rubber, or any equivalent glue known to confer satisfactory adhesion between rubber and conventional thermoplastic fibers such as polyester or polyamide fibers, such as for example the adhesive compositions described in applications WO 2013 / 017421, WO 2013 / 017422, WO 2013 / 017423, as well as epoxy systems known to those skilled in the art.

[0123] By way of example, the gluing process may essentially comprise the following successive steps: passage in a glue bath, followed by dewatering (for example by blowing, calibration) to remove excess glue; then drying for example by passing through an oven or heating tunnel (for example for 30 s at 180°C) and finally heat treatment (for example for 30 s at 230°C).

[0124] Before the above gluing, it may be advantageous to activate the surface of the thermoplastic material, for example by mechanical and / or physical and / or chemical means, to to improve its glue hold and / or its final adhesion to the rubber. A mechanical treatment could consist, for example, of a preliminary step of matting or scratching the surface; a physical treatment could consist, for example, of treatment with radiation such as an electron beam; a chemical treatment could, for example, consist of a preliminary passage in a bath of epoxy resin and / or isocyanate compound.

[0125] Since the surface of the thermoplastic material (based on a thermoplastic elastomer comprising at least one polyether type elastomer block and at least one non-styrenic type thermoplastic block) is generally smooth, it may also be advantageous to add a thickener to the glue used, in order to improve the total glue adhesion of the multi-composite reinforcement during its gluing.

[0126] A person skilled in the art will easily understand that the connection between the thermoplastic polymer layer of the multi-composite reinforcement of the invention and each layer of rubber with which it is in contact in the multi-layer laminate of the invention is definitively ensured during the final curing (crosslinking) of the rubber article, in particular bandage, for which the laminate is intended.

[0127] It goes without saying that in all the particular examples of the invention previously described and schematized in Figures 1 to 7, the CVR single strands, of diameter DM and with a circular cross-section, could be replaced by CVR single strands of a different shape, for example with a rectangular (including square) or other cross-section (for example oval).

[0128] Multi-composite reinforcement or multi-layer laminate finds particularly interesting applications in non-pneumatic bandages.

[0129] A non-pneumatic bandage generally comprises, radially from the inside out: -a load-bearing structure, designed to structurally support at least part of the load and to cooperate with a rim or hub, -an annular shear strip, designed to transmit rolling forces to the load-bearing structure by shear and to contribute at least in part to load-bearing capacity, -and a tread, designed to transmit rolling forces to the annular shear band, to be worn down and to ensure the tire's grip on a surface.

[0130] The load-bearing structure includes, for example, radially from the inside out, means for connecting to a rim or hub, radial elements or spokes, and means for connecting to a shear strip. However, the load-bearing structure does not generally delimit a sealed internal cavity intended to contain a pressurized gas, as in a conventional tire. Therefore, a non-pneumatic tire does not need to have a sealed connection to a rim or hub.

[0131] The annular shear band comprises, in a known manner, radially from the inside to the outside: -a first inner membrane (or ferrule), -a shear layer, -a second outer membrane.

[0132] The vehicle tire according to the invention is advantageously a non-pneumatic tire comprising a tread, an annular band, a plurality of spokes extending transversely and radially within the annular band, and a mounting band for connecting the plurality of spokes to a wheel. Preferably, the multi-composite reinforcement or multi-layer laminate according to the invention is present in at least the shear band and / or at least one spoke of said non-pneumatic tire.

[0133] The multi-composite reinforcement or the multi-layer laminate may also be present in at least one ferrule of the annular shear band (which also corresponds to the radially inner and outer membranes of the annular shear band) of the bandage. EXAMPLE OF AN INVENTION IMPLEMENTATION

[0134] Examples of manufacturing CVR monostrands suitable for the invention are described below, followed by multi-composite reinforcements and multilayer laminates according to the invention based on these CVR monostrands.

[0135] The CVR monostrands suitable for the invention can be prepared according to a process comprising the following main steps: - to create a straight arrangement of glass fibers (filaments) and drive this arrangement in a direction of advancement: - in a vacuum chamber, degas the arrangement of fibers by the action of a vacuum; - upon exiting the vacuum chamber, after degassing, pass through a vacuum impregnation chamber so as to impregnate said arrangement of fibers with a thermosetting resin or resin composition, in liquid state, to obtain an impregnated material containing the glass filaments and the resin; - to pass said impregnated material through a calibration die having a predefined surface area and shape, to impose on it a single-strand shape (for example a monofilament with a round straight section or a ribbon with a rectangular straight section); - downstream of the process, in a UV irradiation chamber, polymerize the resin under the action of UV; - then wind up the resulting single strand for storage.

[0136] All the above steps (arrangement, degassing, impregnation, calibration, polymerization and final winding) are steps known to the person skilled in the art, as are the materials (multifilament fibers and resin compositions) used; they have, for example, been described in one and / or the other of applications EP 1 074 369 and EP 1 174 250.

[0137] It should be recalled in particular that before any impregnation of the fibres, a degassing step of the fibre arrangement by the action of vacuum should advantageously be carried out, in order in particular to strengthen the effectiveness of the subsequent impregnation and above all to guarantee the absence of bubbles inside the final composite monostrand.

[0138] After passing through the vacuum chamber, the glass filaments enter an impregnation chamber which is totally full of impregnation resin, therefore devoid of air: it is in this sense that this impregnation step can be described as "vacuum impregnation".

[0139] The impregnation resin (resin composition) preferably comprises a UV-sensitive (reactive) photoinitiator above 300 nm, preferably between 300 and 450 nm. This photoinitiator is used at a preferential rate of 0.5 to 3%, more preferably 1 to 2.5%. It may also comprise a crosslinking agent, for example at a rate of between 5% and 15% (% by weight of the impregnation composition).

[0140] Preferably, the temperature of the resin (resin composition) in the impregnation chamber is between 50°C and 95°C, more preferably between 60°C and 90°C.

[0141] The so-called "calibration" die allows, by means of a straight section of determined dimensions, generally and preferably circular or rectangular, the proportion of resin relative to the glass fibers to be adjusted while imposing on the impregnated the shape and thickness targeted for the monostrand.

[0142] The polymerization or UV irradiation chamber then has the function of polymerizing, cross-linking the resin under the action of UV.

[0143] The UV irradiation chamber comprises one or more UV irradiators (or heaters). Advantageously, the irradiation chamber comprises a plurality of UV irradiators, that is, at least two (two or more) arranged in a line around the irradiation tube. Each UV irradiator typically comprises one (at least one) UV lamp (preferably emitting in a spectrum from 200 to 600 nm) and a parabolic reflector at the focus of which is the center of the irradiation tube; it delivers a linear power preferably between 2,000 and 14,000 watts per meter. More preferably still, the irradiation chamber comprises at least three, in particular at least four, UV irradiators in a line.

[0144] Even more preferably, the linear power delivered by each UV irradiator is between 2,500 and 12,000 watts per meter, in particular within a range of 3,000 to 10,000 watts per meter.

[0145] Preferably, the irradiation conditions are adjusted so that the temperature of the single strand in CVR, at the outlet of the impregnation chamber, is greater than the Tg (Tgi) of the crosslinked resin; more preferably, this temperature is greater than the Tg (Tgi) of the crosslinked resin and less than 270°C.

[0146] UV heaters suitable for the process of the invention are well known to those skilled in the art, for example those marketed by Dr. Hônle AG (Germany) under the reference "1055 LCP AM UK", equipped with "UVAPRINT" lamps (iron-doped high-pressure mercury lamps). The nominal (maximum) power of each heater of this type is approximately 13,000 Watts, the actual power output being adjustable with a potentiometer between 30 and 100% of the nominal power.

[0147] The diameter of the irradiation tube (preferably made of glass) is preferably between 10 and 80 mm, more preferably between 20 and 60 mm.

[0148] Between the calibration die and the final receiving support, it is preferable to maintain the tensions experienced by the glass fibers at a moderate level, preferably between 0.2 and 2.0 cN / tex, more preferably between 0.3 and 1.5 cN / tex; to control this, it will be possible, for example, to measure these tensions directly at the exit of the irradiation chamber, using appropriate tensiometers well known to those skilled in the art.

[0149] The CVR monostrand thus formed through the UV irradiation chamber, in which the resin is now in a solid state, is then collected for example on a receiving reel on which it can be wound to a very long length.

[0150] Particularly advantageously, the process for manufacturing the CVR single strand of the invention comprises the following essential steps: - the speed (V ir) of passage of the single strand in the irradiation chamber is greater than 50 m / min; - the duration (D ir) of passage of the single strand in the irradiation chamber is equal to or greater than 1.5 s and equal to or less than 10 s; - the irradiation chamber includes a UV-transparent tube (such as a quartz tube or preferably a glass tube), called the irradiation tube, through which the single strand being formed circulates, this tube being traversed by a current of inert gas, preferably nitrogen.

[0151] These combined steps make it possible to achieve the preferred improved properties of the single strand in CVR. In particular, in the absence of neutral gas scanning such as nitrogen in the irradiation tube, it was found that the mechanical properties of the single-strand CVRs degraded quite rapidly during manufacturing, and therefore industrial performance was no longer guaranteed.

[0152] Furthermore, if the irradiation time Dir of the single strand in the irradiation chamber is too short (less than 1.5 s), numerous tests have revealed that the resin is not sufficiently cross-linked, leading to a degradation of mechanical properties, including tensile strength and flexural strength. Conversely, if the irradiation time Dir of the single strand in the irradiation chamber is too long (greater than 10 s, for example), this increases the risk of the resin boiling, thus creating more porosity and degrading mechanical properties, including tensile strength.

[0153] Thus, it is understood that it is thanks to the combination of the steps of the process according to the invention, in particular thanks to the steps of degassing the arrangement of glass filaments by the action of vacuum, in the vacuum chamber, and of polymerization in the irradiation tube through which a current of inert gas flows, at the speed V ir and for the duration of irradiation D ir mentioned above, that CVR single strands are obtained having a porosity rate of less than 2% and a breaking strength greater than 1050 MPa.

[0154] The porosity rate can be measured by microscopy, for example by scanning electron microscopy, preferably using surface calculation software, such as Programme FIJI. The following protocol is preferably used to perform the measurement: - we take a single-strand CVR cross-linked wire, - it is coated with a cold coating resin, such as epoxy, for example in a vacuum coating machine (CitoVac from the company Stuers for example), - The single-strand coated CVR is cut, for example using a hydraulic guillotine, such as the "SH-5214" from the Baileigh company, - The section of the CVR single strand is polished, for example using a mechanical polisher, from the company Mecapol for example, preferably to a final grit of 0.25 µm, - a deposit of 1 to 4 nm of gold is made, for example using a gold metallizer, such as the Cerssington series 108 or 208 from the Eloïse company, - the cross-section of the single strand in CVR is observed using a scanning electron microscope, preferably under vacuum (15kV), and - Using an image processing program, such as FIJI, the surface percentage of porosity is calculated. The term "porosity" of the CVR single strand refers to any gas (particularly air) or void present within the CVR single strand.

[0155] The tensile mechanical properties of the CVR single strand (tensile strength Cr and elongation at break Ar) were measured using an INSTRON 5944 tensile testing machine (BLUEHILL® UNIVERSAL software supplied with the tensile testing machine), according to ASTM D2343, at a temperature of 23°C, on glued (i.e., ready-to-use) CVR single strands. Before measurement, these single strands underwent preconditioning (storage of the single strands for at least 24 hours in a standard atmosphere according to the European standard DIN EN 20139 (temperature of 23 ± 2°C; humidity of 50 ± 5%)). To avoid damage to the glass reinforcements when gripping the sample in the jaws of the tensile testing machine, the heel gluing (Material: 50 mm long cardboard; Adhesive used: Loctite EA 9483 (two-component epoxy)) was carried out in the following manner.The surfaces of the two opposing heels, as well as the reinforcement, were bonded to minimize "dry areas" (areas without adhesive). The heels were held in place for the curing time (12 hours at 23°C) in a jig the same size as the test specimens, with weights placed on the heels to ensure good heel / reinforcement contact. The tensile modulus was determined by linear regression of the stress-strain curve, between 0.1% and 0.6% strain. This strain was recorded by the MultiXtens 1995DA801 extensometer. Tested samples, 260 mm long, were subjected to tensile testing at a nominal speed of 5 m / min, under a preload of 0.5 MPa (reference length 50 mm, distance between the jaws: 150 mm). All results given are an average of 5 measurements.

[0156] The attached [Fig.8] schematically illustrates very simply an example of a device 100 allowing the production of single strands in CVR (10) as schematically shown in [Fig.1].

[0157] A reel 110 is shown containing, in the illustrated example, glass fibers 111 (in the form of multifilaments). The reel is continuously unwound by drive, so as to create a straight arrangement 112 of these fibers 111. Generally, reinforcing fibers are supplied as "rovings," that is, already in groups of fibers wound in parallel on a reel; for example, fibers marketed by Owens Corning under the designation "Advantex" fiber, with a count of 1200 tex (as a reminder, 1 tex corresponds to 1 g / 1000 m of fiber), are used. It is, for example, the traction exerted by the rotating receiver 126 that will allow the parallel fibers and the single-strand CVR to advance along the entire length of the installation 100.

[0158] This arrangement 112 then passes through a vacuum chamber 113 (connected to a vacuum pump not shown), disposed between an inlet pipe 113a and an outlet pipe 113b opening into an impregnation chamber 114, the two pipes preferably having rigid walls and, for example, a greater minimum cross-section (typically twice as much) as the total fiber section and a length much greater (typically 50 times more) than said minimum section.

[0159] As already demonstrated by EP 1 174 250, the use of rigid-walled tubing, both for the inlet orifice in the vacuum chamber and for the outlet orifice of the vacuum chamber and for the transfer from the vacuum chamber to the impregnation chamber, proves compatible with high fiber flow rates through the orifices without breaking the fibers, while also ensuring sufficient sealing. If necessary, experimentally, it is sufficient to determine the largest possible cross-sectional area, given the total cross-section of the fibers to be treated, that still provides sufficient sealing, considering the fiber feed rate and the length of the tubing. Typically, the vacuum inside chamber 113 is, for example, on the order of 0.1 bar, and the length of the vacuum chamber is approximately 1 meter.

[0160] At the outlet of the vacuum chamber 113 and the outlet tube 113b, the arrangement 112 of fibers 111 passes through an impregnation chamber 114 comprising a feed reservoir 115 (connected to a metering pump not shown) and a sealed impregnation reservoir 116 completely filled with an impregnation composition 117 based on a vinyl ester-type curable resin (e.g., "ALTAC® E-Nova FW 2045" from AOC). By way of example, the composition 117 further comprises (at a weight percentage of 1% to 2%) a photoinitiator suitable for UV and / or UV-visible radiation with which the composition will be subsequently treated, for example, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide ("Omnirad 819" from IGM). It may also contain (for example, approximately 5% to 15%) a crosslinking agent such as tris(2-hydroxyethyl)isocyanurate triacrylate (“SR 368” from Sartomer). Of course, the impregnation composition 117 is in liquid form..

[0161] Preferably, the length of the impregnation chamber is several meters, for example between 2 and 10 m, in particular between 3 and 5 m.

[0162] Thus, from the impregnation chamber 114, in a sealed outlet tube 118 (still under primary vacuum), an impregnated material comprising, for example (% by weight) 65% to 75% of solid fibers 111, the remainder (25% to 35%) being made up of the liquid impregnation matrix 117.

[0163] The impregnated material then passes through calibration means 119 comprising at least one calibration die 120 whose channel (not shown here), for example circular, rectangular, or conical in shape, is adapted to the specific manufacturing conditions. By way of example, this channel has a minimum circular cross-section whose downstream orifice has a diameter slightly larger than that of the targeted single strand. Said die has a length that is typically at least 100 times greater than the minimum dimension of the minimum cross-section. Its function is to ensure Providing high dimensional accuracy in the finished product, it can also play a role in regulating the fiber-to-resin ratio. In one possible embodiment, the die 120 can be directly integrated into the impregnation chamber 114, thus eliminating, for example, the need for the outlet tube 118.

[0164] Preferably, the length of the calibration zone is several centimeters, for example between 5 and 50 cm, in particular between 5 and 20 cm.

[0165] Thanks to the calibration means (119, 120) a "liquid" composite monostrand (121) is obtained at this stage, liquid in the sense that its impregnation resin is still liquid at this stage, the shape of whose cross-section is preferably essentially circular.

[0166] At the output of the calibration means (119, 120), the liquid composite monostrand (121) thus obtained is then polymerized by passing through a UV irradiation chamber (122) comprising a sealed glass tube (123) through which the composite monostrand flows; said tube, the diameter of which is typically a few cm (for example 2 to 3 cm), is irradiated by a plurality (here, for example, 4) of UV irradiators (124) in line (Dr. Hônle's "UVAprint" lamps, with a wavelength of 200 to 600 nm) arranged at a short distance (a few cm) from the glass tube.

[0167] Preferably, the length of the irradiation chamber is several meters, for example between 2 and 15 m, in particular between 3 and 10 m.

[0168] In this example, the irradiation tube 123 is traversed by a nitrogen current.

[0169] The irradiation conditions are preferably adjusted so that, at the outlet of the impregnation chamber, the temperature of the CVR single strand, measured on the surface of the latter (for example using a thermocouple), is greater than the Tg (Tgi) of the crosslinked resin (in other words greater than 190°C), and preferably less than 270°C.

[0170] Once the resin has polymerized (cured), the CVR monostrand (125), now in solid state, carried in the direction of arrow F, then arrives on its final receiving reel (126).

[0171] A finished composite block is finally obtained as schematically shown in [Fig. 1], in the form of a continuous CVR monostrand (10), of very long length, whose unit glass filaments (101) are distributed homogeneously throughout the entire volume of hardened resin (102). Its diameter is, for example, approximately 1 mm.

[0172] The process described above can be implemented at high speed, preferably greater than 50 m / min, for example between 50 and 150 m / min.

[0173] Advantageously, before deposition of the thermoplastic sheath (12), the resulting CVR monostrand (10) can be subjected to an adhesion treatment to improve subsequent adhesion between the thermosetting resin (102) described above and the thermoplastic sheath (12). An appropriate chemical treatment may, by example consisting of a preliminary passage in an aqueous bath based on epoxy resin and / or isocyanate compound, followed by at least one heat treatment aimed at removing water and polymerizing the adhesive layer.

[0174] Such adhesion treatments are well known to those skilled in the art. For example, a gluing operation will be carried out by passing the product through an aqueous bath (approximately 94% water) essentially based on epoxy resin (polyglycerol polyglycidyl ether "DENACOL" EX-512 from Nagase ChemteX Corporation, approximately 1%) and isocyanate compound (caprolactam blocked, "GRILBOND" IL-6 from EMS, approximately 5%), gluing step followed by drying (30 s at 185°C) then by heat treatment (30 s at 200°C).

[0175] Once the single strand (10) in CVR is thus finished and glued, the latter is sheathed, covered in a known manner with a layer of thermoplastic material (12), for example by passing the single strand, or where appropriate several single strands arranged in parallel, through an appropriate extrusion head delivering the thermoplastic material in the molten state.

[0176] The sheathing or coating step with the thermoplastic material (12) is carried out in a manner known to those skilled in the art. It consists, for example, simply of passing the CVR monostrand or strands through one or more dies of suitable diameter, in extrusion heads heated to appropriate temperatures, or in a coating bath containing the thermoplastic material previously dissolved in a suitable organic solvent (or mixture of solvents).

[0177] By way of example, the covering of a single strand in CVR of diameter close to 1 mm by a layer of PEBA of minimum thickness E m equal to about 0.2 mm, to obtain a multi-composite reinforcement having a total diameter of about 1.4 mm, is carried out on an extrusion-sheathing line comprising two dies, a first die (counter-die or upstream die) of diameter equal to about 1.05 mm and a second die (or downstream die) of diameter equal to about 1.45 mm, both arranged in an extrusion head heated to about 290°C.

[0178] PEBA (“PEBAX® Rnew® 55R53” from Arkema; ​​Vicat softening point of approximately 156°C, melting point of approximately 167°C) is melted at a temperature of 240°C in the extruder, thus coating the CVR monostrand via the coating head, at a wire feed speed typically of several tens of meters per minute, for an extrusion pump flow rate typically of several tens of cubic centimeters per minute. After this initial coating, the wire can be immersed in a cooling tank filled with cold water to solidify and set the polyester in its amorphous state, then dried, for example, in-line by an air nozzle, or by passing the receiving spool through an oven.

[0179] At the exit of the extrusion head, the coated strand(s) are then cooled sufficiently to solidify the layer of thermoplastic material (12), for example with air or another cold gas, or by passing through a water bath followed by a drying step.

[0180] The multi-composite reinforcement of the invention thus obtained, as schematically shown for example in Fig. 2b, has the following final properties: DM equal to about 1.0 mm; E m equal to about 0.2 mm; DR equal to about 1.4.

[0181] The multi-composite reinforcement of the invention thus manufactured is advantageously usable, in particular in the form of a multi-layer laminate according to the invention, for the reinforcement of tires, pneumatic or non-pneumatic, of all types of vehicles, without particular limitation.

[0182] Particular tests in pneumatic tires were carried out, where multi-composite reinforcements according to the invention as previously manufactured were used as longitudinal reinforcements, i.e. unwired, in crossed working layers instead of conventional steel cables, as described in the aforementioned document EP 1 167 080.

[0183] These tests clearly demonstrated that the multi-composite reinforcements of the invention, thanks to their improved compression properties, did not suffer compression breakage during the manufacture of these pneumatic tires, unlike the CVR monostrands of the prior art as described in EP 1 167 080.

[0184] While significantly lightening pneumatic tires and eliminating the risks associated with corrosion, compared to tires whose belt is conventionally reinforced with steel cables, the multi-composite reinforcements of the invention have also revealed another notable advantage: that they do not increase the rolling noise of pneumatic tires, unlike other known textile (reinforcement) solutions.

[0185] These multi-composite reinforcements of the invention have also demonstrated excellent performance as circumferential reinforcements in non-pneumatic bandages as described above. In particular, they further improve the impact resistance of non-pneumatic bandages compared to those incorporating multi-composite reinforcements not conforming to the invention. EXAMPLES

[0186] The thermoplastic materials tested in accordance with the invention were based on a thermoplastic elastomer comprising at least one polyether type elastomer block and at least one non-styrenic type thermoplastic block: - C1: TPE-A COPE (“Amitel® ECO L460” from Envalior) - C2: TPE-E PEBA (“PEBAX® Rnew® 55R53” from Arkema)

[0187] The thermoplastic materials tested that did not conform to the invention were based on: - C3: Lubrizol TPE-U (“Estane® ECO 12T55D” from Lubrizol Corporation) - C4: TP PA6-1 (“PA6 “Ultramid® B22 NE 01” from BASF) - C5: TP PA6-2 (“PA6 “Akulon® K222-D” from DSM) Measurements and tests used

[0188] Longitudinal tensile tests were carried out under imposed strain on standardized dumbbell-type specimens, based on ISO 527-2 (2012), which was adapted as follows. The strain rate was 500 mm / min, and the specimen underwent five cycles from 0% to 100% with a return to 0%. A final cycle, until the specimen broke, was added. This allowed the elongation at break, Ar%, of the specimen to be recorded after severe cycling.

[0189] The measured data are the area under the curve during the first cycle and the area under the curve of subsequent cycles. The ratio between the area under the curve during the first cycle and subsequent cycles determines the thermoplastic material's ability to release energy following an impact. The closer this ratio is to 100%, the better the material's energy release during the impact.

[0190] Table 1 above presents the results obtained.

[0191] [Tables 1] Cl C2 C3 C4 C5 Area under the curve in the first cycle 98.65 149.3 140.6 357.76 345.5 Area under the curve in cycle 2 30.27 47.1 40.4 44.45 38.5 Ratio of area cycle 2 / area cycle 1 (%) 30.7 31.5 28.7 12.42 11.2 Area under the curve in cycle 3 28.2 41.7 35.6 38.34 27.9 Ratio of area cycle 3 / area cycle 2 (%) 28.6 27.9 25.3 10.86 8.1 Area under the curve in cycle 4 27.21 39.3 33.3 36.66 31.8 Ratio of area cycle 4 / area cycle 3 (%) 27.6 26.3 23.7 10.25 9.2 Area under the curve in cycle 5 26.63 35.1 31.8 34.77 30.0 Ratio of area cycle 5 / area cycle 4 (%) 27 23.5 22.6 9.72 8.7

[0192] The results presented in this table show that the ratio of area under the curve between 2 cycles, called Energy of restitution, of the compositions according to the invention (Cl, C2) is greater than that of the compositions not according to the invention (C3 to C5), regardless of the successive cycles compared.

[0193] The thermoplastic material compositions according to the invention are therefore materials of choice for covering single strands (10) of glass-resin composite comprising glass filaments (101) embedded in a crosslinked resin (102) of a multi-composite reinforcement (RI, R2). This allows the reinforcement according to the invention to be more resistant while deforming to ensure significant impact resistance, and thus to be able to support more load.

Claims

Demands

1. Multi-composite reinforcement (RI, R2) comprising at least one single strand (10) of glass-resin composite comprising glass filaments (101) embedded in a crosslinked resin (102), the at least one single strand being covered with a layer of a thermoplastic material (12), characterized in that the thermoplastic material (12) is based on a thermoplastic elastomer comprising at least one polyether-type elastomer block and at least one non-styrenic-type thermoplastic block.

2. Multi-composite reinforcement according to claim 1, wherein the crosslinked resin (102) is based on a resin composition comprising at least one photocurable resin and a crosslinking system comprising a photoinitiator agent.

3. Multi-component reinforcement according to claim 2, wherein the photocurable resin is a UV-curable resin and the photoinitiator is a UV-reactive photoinitiator beyond 300 nm.

4. Multi-composite reinforcement according to any one of the preceding claims, wherein the monostrand (10) has an average diameter DM ranging from 0.2 to 1.3 mm, preferably from 0.25 to 1.3 mm, preferably from 0.3 to 1.2 mm.

5. Multi-composite reinforcement according to any one of the preceding claims, wherein the minimum thickness (Em) of the layer of thermoplastic material covering the or each monostrand (10) is between 0.05 and 0.5 mm, preferably between 0.1 and 0.4 mm.

6. Multi-composite reinforcement according to any one of the preceding claims, wherein the polyether type elastomer block(s) of the thermoplastic elastomer are selected from polyethers having a glass transition temperature, Tg, below 25°C, preferably having a Tg within a range of -110°C to 25°C, preferably -70°C to 20°C.

7. Multi-composite reinforcement according to any one of the preceding claims, wherein the polyether elastomer block(s) of the thermoplastic elastomer are selected from the group consisting of polytetramethylene glycol (PTMG), polyethylene glycol (PEG), polypropylene ether glycol (PPG), polyhexamethylene ether glycol, and polytrimethylene ether glycol. (PO3G), poly(3-alkyltetrahydrofurans), and mixtures thereof, preferably in the group consisting of polytetramethylene glycol (PTMG), polyethylene glycols (PEG) and mixtures thereof.

8. Multi-composite reinforcement according to any one of the preceding claims, wherein the non-styrenic thermoplastic block(s) of the thermoplastic elastomer are selected from the group consisting of polyamides, polyesters and their mixtures, preferably the non-styrenic thermoplastic block(s) of the thermoplastic elastomer are selected from the group consisting of polyamides.

9. Multi-composite reinforcement according to any one of the preceding claims, wherein the non-styrenic thermoplastic block(s) of the thermoplastic elastomer are selected from the group consisting of PA6, PAU, PA12 polyamides and their mixtures.

10. Multi-composite reinforcement according to any one of the preceding claims, wherein the mass fraction of non-styrenic thermoplastic block in the thermoplastic elastomer is in the range of 15% to 60%, preferably 20% to 50%.

11. Multi-component reinforcement according to any one of the preceding claims, wherein the thermoplastic elastomer is selected from the group consisting of polyether and polyamide block copolymers (PEBA).

12. Multi-composite reinforcement according to any one of the preceding claims, wherein the thermoplastic elastomer has a melting temperature, Tf, in the range of 120°C to 195°C, preferably 130°C to 180°C, preferably 135°C to 170°C.

13. Laminate comprising at least one multi-composite reinforcement according to any one of claims 1 to 12, disposed between and in contact with two layers of which at least one layer is a rubber composition and / or at least one layer is a thermoplastic.

14. Article comprising a multi-composite reinforcement according to any one of claims 1 to 12, or a multi-layer laminate according to claim 13.

15. A vehicle tire comprising a multi-composite reinforcement according to any one of claims 1 to 12, or a multi-layer laminate according to claim 13, the tire being of preferably a non-pneumatic tire comprising a tread, an annular band, a plurality of spokes extending transversely and radially within the annular band, a mounting band for connecting the plurality of spokes with a wheel, and the multi-composite reinforcement or multi-layer laminate preferably being present in at least the shear band and / or at least one spoke of said non-pneumatic tire.

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