WO2016189209A1

WO2016189209A1 - Multi-composite reinforcement made from improved glass-resin

Info

Publication number: WO2016189209A1
Application number: PCT/FR2015/051410
Authority: WO
Inventors: Antonio Delfino
Original assignee: Compagnie Generale Des Etablissements Michelin; Michelin Recherche Et Technique S.A.
Priority date: 2015-05-28
Filing date: 2015-05-28
Publication date: 2016-12-01
Also published as: BR112017025585A2; KR102360510B1; KR20180012760A; CN107709417A

Abstract

The invention relates to a multi-composite reinforcement (R1, R2) including one or more monofilament(s) (10) made from glass-resin composite comprising glass filaments (101) embedded in a thermoset resin (102) of glass transition temperature Tg₁, characterised in that a layer of thermoplastic material (12) covers the monofilament or, in the case of multiple monofilaments, covers each monofilament individually, all of the monofilaments collectively or at least some of the monofilaments. According to the invention, the monofilament or, in the case of multiple monofilaments, all of the monofilaments or at least some of the monofilaments has/have the following properties: a temperature Tg₁ equal to or greater than 190°C, an elongation at break A _(M) equal to or greater than 4.0%, and an initial modulus in extension E _(M) greater than 35 GPa. The invention also relates to a multilayer laminate comprising such a multi-composite reinforcement. The invention further relates to a pneumatic or non-pneumatic tyre reinforced with such a multilayer laminate or multi-composite reinforcement.

Description

IMPROVED GLASS-RESIN MULTI-COMPOSITE REINFORCEMENT

1. DOMAIN OF THE INVENTION

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

It relates more particularly to single-component composite reinforcements of the "CVR" type (abbreviated for Glass-Resin Composite) with high mechanical and thermal properties, comprising unidirectional continuous multifilament glass fibers embedded in a thermoset resin and particularly usable as reinforcing elements of these bandages.

2. STATE OF THE ART

The designers of bandages have long been looking for "reinforcements" (elongated reinforcing elements) of textile or composite type, with low density, which can advantageously and effectively substitute for conventional metal wires or cables, with a view in particular to reducing the weight of these bandages and also to overcome any corrosion problems.

Thus, patent EP 1 167 080 (or US Pat. No. 7,032,637) has already described a "CVR" monofilament, with high mechanical properties, comprising unidirectional, continuous glass fibers impregnated in a reticulated resin of the vinylester type. This single-strand has, besides a high compression breaking stress, greater than its extension tensile stress, an elongation at break of the order of 3.0 to 3.5% and an initial expansion module of at least GPa; its thermoset resin has a Tg (glass transition temperature) greater than 130 ° C and an initial module in extension of at least 3 GPa.

With the above properties, this patent EP 1,167,080 has shown that it was advantageously possible to substitute steel cables for such single CVR monobrins, arranged in particular under the tread in parallel sections, as new elements. reinforcement of pneumatic tire belts, thereby significantly reducing the tire structure. However, it has unexpectedly been found that these composite monobrins of the prior art, when used as belt reinforcements of certain pneumatic tires, could undergo a number of breakages in compression, by collapse or buckling of their tires. during the actual manufacture of these bandages, in particular during the shaping step and / or the final mold-baking step of these bandages, which is known to be carried out under high pressure and very high temperature, typically above 160 ° C. Thus, the applicants, in the patent application WO 2015/014578 published recently, have already proposed a new CVR monofilament with improved properties of Tg, elongation at break and modulus, giving the latter properties in compression, particularly at elevated temperature, which are significantly improved over those of the prior art CVR monobrins described in the aforementioned application EP 1 167 080, and which make it possible to overcome the aforementioned problem.

Experience shows, however, that the composite straighteners described in the patent documents described above can be further improved, especially for their use in tires, pneumatic or non-pneumatic, for vehicles.

3. BRIEF DESCRIPTION OF THE INVENTION

Continuing their research, the Applicants have discovered a new reinforcement, based on single-strand CVR, whose properties in compression, flexion or transverse shear are significantly improved over those of the composite monobrins of the prior art.

Thus, according to a first object, the present invention relates (with reference to the appended FIGS. 1 and 2) to a multi-composite reinforcement (R1, R2) comprising one or more monofilres (10) made of glass-resin composite comprising filaments. of glass (101) embedded in a thermoset resin (102) whose glass transition temperature is denoted Tgi, said multi-composite reinforcement being characterized in that: - a layer of a thermoplastic material (12) covers said single-strand or, if they are several, individually each single stranded or collectively all or at least some of the single strands;

said single strand or, if there is more than one, all or at least some of the strands has the following characteristics: a temperature Tgi equal to or greater than 190 ° C;

an elongation at break denoted A _(M) , measured at 20 ° C, equal to or greater than 4.0%; an initial module in extension noted E _(M) , measured at 20 ° C, greater than 35 GPa. The thermoplastic and therefore thermofusible nature of the material covering the single strands in CVR, also makes it possible, very advantageously, to manufacture in a manner of "gluing or thermal assembly" a wide variety of multi-composite reinforcements (multi-stranded) having different shapes. and straight sections, this by at least partial melting of the covering material, then cooling of all strands sheathed thermoplastic material once they arranged together, arranged appropriately.

The invention also relates to any multilayer laminate comprising at least one multi-composite reinforcement according to the invention, disposed between and in contact with two layers of rubber composition, in particular diene rubber.

The invention also relates to any finished article or semi-finished product made of plastic or rubber comprising a multi-composite reinforcement or a multilayer laminate according to the invention. The invention relates more particularly to a tire, pneumatic or non-pneumatic tire, the multi-composite reinforcement or the multilayer laminate being present in the belt of the tire or in the carcass reinforcement of the tire, or in the bead zone of the tire.

The invention also relates to the use of a multi-composite or multilayer laminate reinforcement according to the invention, as reinforcing element for semifinished articles or products made of plastic or rubber such as pipes, belts, conveyor belts, pneumatic or non-pneumatic tires for vehicles, and such articles, semi-finished products and bandages themselves, both in the green state (ie before firing or vulcanisation) and in the cooked state (after cooking). The bandages of the invention, in particular, may be intended for motor vehicles of the tourism, 4x4, "SUV" (Sport Utility Vehicles) type, but also for industrial vehicles chosen from light trucks, "heavy vehicles" - ie , metro, bus, road transport equipment (trucks, tractors, trailers), off-the-road vehicles -, agricultural or civil engineering machinery, airplanes, other commercial vehicles for transport or handling.

The multi-composite reinforcement and the multilayer laminate of the invention are particularly useful as reinforcing elements in crown reinforcement (or belts) or in carcass reinforcement of bandages, as described in particular in documents EP 1 167 080 or US 7,032,637 cited above. They could also be present in the bead area of such bandages. The multi-composite reinforcement of the invention is also advantageously usable, because of its low density and its properties in compression, flexion and transverse shear which are improved, as reinforcing element in tires or non-pneumatic type flexible wheels. that is, 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 Pat. No. 6,769,465, EP 1 359 028 or US Pat. No. 6,994,135, EP 1 242 254 or US Pat. No. 6,769,465, US Pat. 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 rigid mechanical element intended to ensure the connection between the flexible tire and the hub of a wheel, they replace the assembly constituted by the tire, the rim and the disc as known on most current road vehicles. The multi-composite reinforcement of the invention is particularly useful for use in bands or annular layers of shear ("shear rent") belt forming such bandages.

The invention as well as its advantages will be easily understood in the light of the detailed description and the following exemplary embodiments, as well as FIGS. 1 to 9 relating to these examples which schematize (without respecting a specific scale): transverse section, a CVR monofilament (10) that can be used in a multi-composite reinforcement according to the invention (FIG.

in cross-section, two examples (R-1 and R-2) of multi-composite reinforcements according to the invention (FIG 2a and FIG 2b);

in cross-section, another example (R-3) of multi-composite reinforcement according to the invention (FIG 3);

in cross-section, another example (R-4) of multi-composite reinforcement according to the invention (FIG 4);

in cross-section, another example (R-5) of multi-composite reinforcement according to the invention (FIG 5);

- In cross section, another example (R-6) of multi-composite reinforcement according to the invention (Figure 6);

in cross section, an example (20) of multilayer laminate according to the invention comprising a multi-composite reinforcement according to the invention (R-7) itself embedded in a diene rubber matrix (Figure 7);

a device that can be used for manufacturing a CVR monofilament (10) that can be used as the basic constituent element of a multi-composite reinforcement according to the invention (FIG.

in radial section, an example of a pneumatic tire according to the invention, incorporating a multi-composite reinforcement and a multilayer laminate according to the invention (FIG 9). 4. DETAILED DESCRIPTION OF THE INVENTION

In the present application, unless expressly indicated otherwise, all the percentages (%) indicated are percentages by mass.

Any range of values designated by the expression "between a and b" represents the range of values from more than a to less than b (i.e., terminals a and b excluded) while any range of values designated by the expression "from a to b" means the range from a to b (i.e., including the strict limits a and b).

Unless expressly indicated otherwise, all the mechanical properties in extension or in compression are measured (on single-core, thermoset resin or thermoplastic material) at a temperature of 20 ° C.

The invention therefore relates to a reinforcement of the multi-composite type, in other words a composite composite, used especially for the reinforcement of rubber articles such as tires for vehicles, which has the essential feature of comprising at least, firstly a single-strand or several single strand (10) glass-resin composite (abbreviated "CVR") as schematized in Figure 1, comprising glass filaments (101) embedded in a thermoset resin (102) whose glass transition temperature is denoted by Tgi, said single-stranded material or, if there is more than one, all or at least some of the single strands, having the following essential characteristics:

a temperature Tgi equal to or greater than 190 ° C .;

an elongation at break A _(M) , measured at 20 ° C., equal to or greater than 4.0%; and

an initial module in extension E _(M) , measured at 20 ° C., greater than 35 GPa.

Typically, the glass filaments are present in the form of a single multifilament fiber or of several multifilament fibers (if they are several, they are preferably essentially unidirectional), each of which may comprise several tens, hundreds or even thousands of fibers. unit glass filaments. These very fine unitary filaments generally and preferably have an average diameter of the order of 5 to 30 μιη, more preferably 10 to 20 μιη.

By "resin" or "thermoset resin" is meant here the resin as such and any composition based on this resin and comprising at least one additive (that is to say one or more additives). This resin is of course cross-linked (for example photocured and / or thermally hardened), in other words in the form of a network of bonds. three-dimensional, in a state specific to so-called thermosetting polymers (as opposed to so-called thermoplastic polymers).

The temperature Tgi is preferably greater than 195 ° C., more preferably greater than 200 ° C. It is measured (as Tg ₂ and Tf described below) in a known way by Differential Scanning Calorimetry (DSC), in the second pass, for example, and unless otherwise specified in the present application, according to the ASTM D3418 standard of 1999 (DSC apparatus "822-2" from Mettler Toledo, nitrogen atmosphere, samples previously brought from room temperature (23 ° C) to 250 ° C (10 ° C / min), then rapidly cooled (quenching) to a lower temperature preferably at least 50 ° C at the temperature Tg considered (for example up to 23 ° C), before final recording of the DSC curve of this quenching temperature (for example 23 ° C) up to 250 ° C, at a ramp of 10 ° C / min). The elongation at break A _(M) of the single strand or, if they are several, all or at least a part (preferably the majority) of single strands, is preferably greater than 4.2%, more preferably greater than at 4.4%. The initial modulus in extension E _(M) of the single strand or, if they are several, of all or at least a part (preferably the majority) of single strands, is preferably greater than 40 GPa, more preferably greater than 42 GPa .

The mechanical properties in extension (modulus E and elongation at break A) are measured in a known manner by means of an "INSTRON" traction machine of the type 4466 (BLUEHILL-2 software supplied with the traction machine), according to ASTM D 638, on CVR monobrins or raw composite multi-composites reinforcements that is to say unsized, or glued (that is to say ready to use), or extracts of the semi-finished product or rubber article that they reinforce. Before measurement, these monobrins or multi-composite reinforcements are subjected to a preliminary conditioning (storage for at least 24 h in a standard atmosphere according to the European standard DIN EN 20139 (temperature of 23 ± 2 ° C, hygrometry of 50 ± 5%> )). The tested samples are pulled over an initial length of 400 mm at a nominal speed of 100 m / min, under a standard pretension of 0.5 cN / tex. All results given are an average of 10 measurements.

According to another preferred embodiment, for an improved compromise of thermal and mechanical properties of the reinforcement of the invention, the real part of the complex module denoted E'i90 _(M) of the single strand or, if there are several, of the totality or at least a portion (preferably the majority) of single strands, measured at 190 ° C by the DTMA method, is greater than 30 GPa. E ' _{I9O (M)} is more preferably greater than 33 GPa, still more preferably greater than 36 GPa. According to a particularly preferred embodiment, in the case where several single strands are present in the multi-composite reinforcement of the invention, each of the single strands has the essential characteristics of Tgi, A _(M ) and E _(M) as stated. previously; more preferably, each of them has the preferential characteristics, especially more preferred, of Tgi, A _(M ), E _(M ) and ΕΊ ₉ Ο (Μ) as stated above.

According to another preferred embodiment, for an optimized compromise of thermal and mechanical properties of the reinforcement of the invention, the ratio E ' _T g1' - 2S) (M) / E '20 (Μ) is greater than 0.85 preferably greater than 0.90; E ' ₂ o (M) and E' ( _T gi '_ 25) (M) represent the real part of the complex modulus of the single strand, measured by DMTA respectively at 20 ° C and at a temperature expressed in ° C equal to (Tg ₂ '- 25), in which Tgi' represents the glass transition temperature (Tg) measured this time by DMTA. According to another more preferential embodiment, the ratio E ' _T gi' - ιοχΜ) / Ε ' ₂ ο (Μ) is greater than 0.80, preferably greater than 0.85, E' _(Tg i '_ ιοχΜ ) being the real part of the complex module of the monobrin measured by DMTA at a temperature in ° C equal to (Tgi '- 10).

The measurements of E 'and Tgi' are carried out in a known manner by DMTA ("Dynamical Mechanical Thermal Analysis"), with a "DMA ⁺ 450" viscoanalyzer from ACOEM (France), using the "Dynatest 6.83 / 2010" software piloting tests. bending, pulling or twisting.

According to this device, the three-point bending test does not allow in known manner to enter the initial geometric data for a single-strand circular section, we can only introduce the geometry of a rectangular section (or square). In order to obtain an accurate measurement of the modulus E 'for a monofilament of diameter denoted here as D _M (see FIG.1), the software therefore conventionally introduces a square section of side "a" having the same moment of inertia. surface, this in order to work at the same stiffness R tested test pieces.

The well-known relations that follow must apply (E being the modulus of the material, I _s the moment of inertia of surface of the body considered, and * the symbol of multiplication):

R ^- Ecomposite Circular Uection ^- E _C omposite Square section with. Circular Isection 1 * DM / 64 and Square Isection & / 12

It is easy to deduce the value of the "a" side of the equivalent square with the same surface inertia as that of the (circular) section of the diameter of the single-core D, according to the equation: a = D _M * (TI / 6) ⁰ ' ²⁵ . In the case where the cross-section of the tested sample is not circular (or rectangular), whatever its particular shape, the same method of calculation will apply by determining beforehand the moment of inertia of surface I _s on a straight cut of the tested sample.

The test specimen to be tested, generally of circular section and of diameter D _M , has a length of 35 mm. It is arranged horizontally on two supports 24 mm apart. A repeated bending stress is applied perpendicularly to the center of the test piece, halfway between the two supports, in the form of a vertical displacement of amplitude equal to 0.1 mm (deformation therefore asymmetrical, the inside of the specimen being stressed only in compression and not in extension), at a frequency of 10 Hz.

The following program is then applied: under this dynamic stress, the test piece is gradually heated from 25 ° C to 260 ° C with a ramp of 2 ° C / min. At the end of the test we obtain the measurements of the elastic modulus E ', the viscous modulus E "and the loss angle (δ) as a function of the temperature (where E' is the real part and E" the imaginary part of the complex module); Tgi 'is the vitreous transition temperature corresponding to the maximum (peak) of tan (δ). According to a preferred embodiment, the CVR monofilament or, if they are several, all or at least a part (preferably the majority) of the CVR monobrins, has an elastic deformation in flexural compression which is greater than 3 , 0%, more preferably greater than 3.5%, in particular greater than 4.0%; according to another preferred embodiment, their breaking stress in flexural compression is greater than 1000 MPa, more preferably greater than 1200 MPa, in particular greater than 1400 MPa.

The above properties in flexural compression are measured on single-stranded CVR as described in the aforementioned document EP 1 167 080, by the so-called loop test method (D. Inclair, J. App .. Phys 21, 380, 1950). In the present case, a loop is made which is gradually brought to the breaking point. The nature of the fracture, easily observable because of the large size of the section, immediately reveals that the single-core, bending until it ruptures, breaks on the side where the material is in extension, which the 'we identify by simple observation. Since in this case the dimensions of the loop are important, it is possible at any time to read the radius of the circle inscribed in the loop. The radius of the circle inscribed just before the breaking point corresponds to the critical radius of curvature, denoted by Rc.

The following formula then makes it possible to determine by calculation the critical elastic deformation denoted Ec (where r corresponds to the radius of the single strand, that is to say D _M / 2): Ec = r / (Rc + r)

The flexural compression failure stress denoted σ _ε is obtained by calculation by the following formula (where E is the initial module in extension):

Oc = Ec * E

When the rupture of the loop appears in the extension part, it can be concluded that, in bending, the compression breaking stress is greater than the extension tensile stress.

Bending of a rectangular bar can also be performed by the so-called three-point method (ASTM D 790). This method also makes it possible to verify, visually, that the nature of the rupture is indeed in extension.

According to a preferred embodiment, the breaking stress in pure compression is greater than 700 MPa, more preferably greater than 900 MPa, in particular greater than 1100 MPa. To avoid buckling of the CVR monobrin under compression, this quantity is measured according to the method described in the publication "Critical Compressive Stress for Continuous Fiber Unidirectional Composites" by Thompson et al, Journal of Composite Materials, 46 (26), 3231-3245. .

Preferably, in each CVR monofilament or, if they are several, in all or at least a part (preferably the majority) of the CVR monobrins, 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 which is less than 2.0 degrees, more preferably less than 1.5 degrees, this inclination (or misalignment) being measured as described in the above publication by Thompson et al.

Preferably, in the multi-composite reinforcement of the invention, the CVR monofilament or, if they are several, all or at least a part (preferably the majority) of the CVR monobrins has a weight content of glass filaments which is between 60 and 80%, more preferably between 65 and 75%.

This weight ratio is calculated by comparing the title of the initial fiberglass with the title of the single strand in final CVR. The titre (or linear density) is determined on at least three samples, each corresponding to a length of 50 m, by weighing this length; the title is given in tex (weight in grams of 1000 m of product - as a reminder, 0, 111 tex equals 1 denier). According to another preferred embodiment, in the multi-composite reinforcement of the invention, the single-strand CVR or, if they are several, the whole or at least a part (preferably the majority) of the single strands in CVR has a density (or density in g / cm ³ ) which is between 1.8 and 2.1. It is measured (at 23 ° C) using a specialized scale of the Mettler Toledo company of the "PG503 DeltaRange"type; the samples, a few cm, are successively weighed in the air and immersed in ethanol; the device software then determines the average density over three measurements. The diameter denoted D _M of the monofilament in CVR, or of each monofilament in CVR if they are several, is preferably between 0.2 and 2.0 mm, more preferably between 0.3 and 1.5 mm.

This definition covers both monofilaments of substantially cylindrical shape (circular cross section) and monofilaments of different shape, for example oblong monofilaments (more or less flattened shape) or rectangular cross section. In the case of a non-circular section and unless otherwise specified, D _M is conventionally the so-called clutter diameter, that is to say the diameter of the cylinder of imaginary revolution enveloping the single-strand, in other words the diameter of the circumscribed circle surrounding its cross section.

The resin used is, by definition, a crosslinkable resin (ie, hardenable resin) capable of being crosslinked, cured by any known method, in particular by UV (or UV-visible) radiation, preferably emitting in a spectrum of at least 300 nm at 450 nm.

As a crosslinkable resin, a polyester or vinyl ester resin, more preferably a vinylester resin, is preferably used. By "polyester" resin is meant in known manner an unsaturated polyester resin. Vinylester resins are well known in the field of composite materials.

Without this definition being limiting, the vinylester resin is preferably of the epoxyvinylester type. It is more preferable to use a vinylester resin, in particular of the epoxide type, which is at least partly based (that is to say grafted on a structure of the type) novolac (also called phenoplast) and / or bisphenol, or preferably a vinylester resin containing novolac, bisphenolic, or novolak and bisphenol.

Preferably, the initial modulus in extension of the resin once thermoset (crosslinked), measured at 23 ° C., is greater than 3.0 GPa, more preferably greater than 3.5 GPa. A novo lacquer epoxy vinyl ester (part in square brackets in formula I below), for example, in a known manner, corresponds to the following formula (I):

(I)

A bisphenol A-based epoxy vinyl ester (part in square brackets of the formula (II) below) for example meets the formula (the "A" recalling that the product is manufactured using acetone):

A novolak and bisphenol type epoxy vinyl ester has shown excellent results. By way of example of such a resin, mention may be made in particular of the vinylester resins "ATLAC 590" and "E-Nova FW 2045" from the company DSM (diluted with approximately 40% styrene) described, for example, in the EP applications -A-1 074 369 and EP-A-1 174 250. Epoxymylester resins are available from other manufacturers such as for example AOC (USA - "VIPEL" resins).

According to another essential characteristic of the invention, as already indicated, a layer of a thermoplastic material (12) covers the single-strand CVR or, if they are several, individually each single strand or collectively all or at least a part ( preferably the majority) monobrins, to constitute the multi-composite reinforcement of the invention.

It has been found that the presence of this sheath, a layer of thermoplastic material, gives the CVR monobrins and therefore the multi-composite reinforcement of the invention endurance properties in compression, flexion or transverse shear (perpendicular to the axis of the monobrin) which are noticeably improved, especially at a high temperature, compared to those of the CVR single-stranders of the prior art.

The glass transition temperature denoted Tg ₂ of this thermoplastic material (12) is preferably greater than -30 ° C, more preferably greater than 20 ° C; it is even more preferably greater than 50 ° C., in particular greater than 70 ° C. Its melting temperature (denoted Tf) is preferably greater than 100 ° C, more preferably greater than 150 ° C, even more preferably greater than 200 ° C. Preferably, the minimum thickness (denoted E _m ) as schematized for example in FIG. 2, of the layer of thermoplastic material covering the single-strand or each single strand, if they are several, is between 0.05 and 0.5 mm, more preferably between 0.1 and 0.4 mm, in particular between 0.1 and 0.3 mm. Preferably, the initial modulus in extension of this thermoplastic material (12) is between 300 and 3000 MPa, more preferably between 500 and 2500 MPa, still more preferably between 500 and 1500 MPa; its elastic elongation is preferably greater than 5%, more preferably greater than 8%, in particular greater than 10%; its elongation at break is preferably greater than 10%, more preferably 15%, in particular greater than 20%.

Typically, the thermoplastic material is a polymer or a polymeric composition (i.e. a composition based on at least one polymer and at least one additive). This thermoplastic polymer is preferably selected from the group consisting of polyamides, polyesters, polyimides and mixtures of such polymers, more particularly in the group consisting of polyesters, polyetherimides and mixtures of such polymers. Among the aliphatic polyamides, there may be mentioned polyamides 4-6, 6, 6-6, 11 or 12. The thermoplastic polymer is preferably a polyester; among the polyesters, mention may be made more particularly of PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PBT (polybutylene terephthalate), PBN (polybutylene naphthalate), PPT (polypropylene terephthalate), PPN (polypropylene naphthalate). According to another preferred embodiment, the thermoplastic polymer is a polyetherimide (PEI), for example the product "ULTEM 1000" from GE Plastics.

To the polymer or mixture of polymers above, may be optionally added to form a polymeric composition, various additives such as dye, filler, plasticizer, antioxidant or other stabilizer. We can advantageously add to the material thermoplastic above, compatible components, preferably themselves thermoplastic, capable of promoting adhesion to a diene rubber matrix, for example TPS (styrene thermoplastic) elastomers of the unsaturated type, in particular epoxidized type, as described for example in WO 2013/117474 and WO 2013/117475.

According to a preferred embodiment, the sheath (12) comprises a single thermoplastic material. Alternatively, the sheath (12) could however comprise several different thermoplastics.

As a thermoplastic polymer, one could also use thermoplastic elastomers (TPE), including TPS elastomers, saturated or unsaturated, as described for example in the applications WO2010 / 105975, WO2010 / 136389, WO2011 / 012521, WO2011 / 051204 , WO2012 / 016757, WO2012 / 038340, WO2012 / 038341, WO2012 / 069346, WO2012 / 104279, WO2012 / 104280 and WO2012 / 104281, or mixtures of nonelastomeric polymers as described above and such thermoplastic elastomers.

It will be recalled here that thermoplastic elastomers (for example styrenic), of intermediate structure between thermoplastic polymers and elastomers, consist in known manner of rigid thermoplastic blocks (for example polystyrene) linked by flexible elastomer blocks, for example polybutadiene, polyisoprene or poly (ethylene / butylene). This is the reason why, in known manner, the TPE or TPS copolymers are generally characterized by the presence of two glass transition peaks, the first peak (the lowest temperature, generally negative) being relative to the elastomeric block of the copolymer , the second peak (the highest temperature, generally and preferably positive, corresponding to Tg ₂ ) being relative to the thermoplastic part (for example styrene blocks) of the copolymer. The elongation at break noted κ>, measured at 20 ° C, of the multi-composite reinforcement of the invention is preferably equal to or greater than 3.0%, more preferably equal to or greater than 3.5%. Its initial modulus in extension noted E _(R ), measured at 20 ° C, is preferably greater than 9 GPa, more preferably greater than 12 GPa. FIG. 2 schematizes, in cross section, two examples (R1 and R-2) of multi-composite reinforcements according to the invention, in which a single CVR monofilament (10) as described above, for example of diameter D _M equal to 1 mm, was covered by its layer, sheath of thermoplastic material, for example polyester such as PET, of minimum thickness denoted E _m (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).

The diameter (for Fig. 2a) or the thickness (for Fig. 2b) noted (e) D _R of these reinforcements R1 and R-2 of the invention equal to D _M +2 E _m is therefore about 1.4 mm in these two examples.

Thanks to the combined presence of its glass filaments (101), its thermoset matrix (102) and the thermoplastic sheath (12), which to a certain extent fulfills a shrinking function of the CVR monofilament (10), the multi-composite reinforcement of the invention (R1, R-2) is characterized by improved transverse cohesion, high dimensional, mechanical and thermal stability.

In the case where several single-stranded CVRs are used, the thermoplastic layer or sheath can be deposited individually on each single-strand as illustrated for example in FIGS. 2, 5 and 6, or collectively deposited on several of the suitably arranged single strands, for example example aligned in a main direction, as illustrated for example in Figures 3, 4 and 7.

FIG. 3 schematizes, in cross-section, another example of a multi-composite reinforcement (R-3) in which two CVR monobrins (10), of substantially the same diameter (for example equal to approximately 1 mm), have been covered together with a sheath of thermoplastic material (12), for example polyester such as PET, of minimum thickness E _m (for example equal to about 0.25 mm). In these examples, the cross section of the multi-composite reinforcement is rectangular, of thickness D _R equal to D _M +2 E _m , for example of the order of 1.5 mm.

FIG. 4 schematizes, in cross-section, another example of a multi-composite reinforcement (R-4) in which four CVR monobrins (10), of substantially the same diameter (for example equal to about 0.5 mm) have were covered with a sheath of thermoplastic material, for example polyester such as PET, to form a multi-composite reinforcement of substantially square cross-section, of thickness D _R.

The thermoplastic and therefore thermally fusible nature of the material (12) covering each strand (10) made of CVR makes it very advantageous to manufacture by thermal bonding a large variety of multi-strand multi-strand reinforcements having different shapes and straight sections, this being by at least partial melting of the covering material, then cooling of all the strands (10) sheathed thermoplastic material (12) once they are arranged together, arranged appropriately. This at least partial melting will be conducted at a temperature preferably between the melting temperature Tf of the thermoplastic material (12) and the glass transition temperature Tgi of the thermoset resin (102).

Thus, FIG. 5 schematizes, in transverse section, another example of a multi-composite reinforcement (R-5) according to the invention in which two elementary multi-composite reinforcements R-2 as shown diagrammatically in FIG. 2b) were brought into contact, glued, welded together by superficial melting of their thermoplastic sheath (12) and cooling step to obtain this reinforcement R-5 thickness D _R. FIG. 6 shows another example of a multi-composite reinforcement according to the invention in which three elementary multi-composite reinforcements R-2 as schematized in FIG 2 (FIG 2b) have been aligned, brought into contact and then glued, welded together by superficial melting of their thermoplastic sheath and cooling, to obtain another multi-composite reinforcement (R-6) of cross section of thickness D _R.

The invention also relates to a multilayer laminate comprising at least one multi-composite reinforcement according to the invention as described above, disposed between and in contact with two layers of rubber or elastomer composition, in particular diene. In the present application, is meant in known manner, by:

"laminate" or "multilayer laminate", as defined in the International Patent Classification: any product having at least two layers, of flat or non-planar shape, in contact with each other, the latter being either unrelated, connected to each other; the term "bound" or "connected" should be interpreted extensively to include all connecting or joining means, in particular by gluing; "Diene" rubber: any elastomer (elastomer alone or mixture of elastomers) which is derived, at least in part (ie, a homopolymer or a copolymer), from monomers dienes, that is to say from monomers carrying two double carbon-carbon bonds, whether the latter are conjugated or not.

FIG. 7 represents an example of such a multilayer laminate (20) comprising a multi-composite reinforcement (R-7) consisting of three CVR monobrins (10a, 10b, 10c) (as shown diagrammatically in FIG. collectively embedded in their thermoplastic sheath (12), this reinforcement according to the invention R-7 itself being coated with a sheath (14) of elastomer for example diene, to form a multilayer laminate according to the invention.

This lightweight, high-performance multilayer laminate, which is insensitive to corrosion, can advantageously replace, in vehicle tires, conventional rubber plies reinforced with steel cables or conventional textile cords. In addition to the presence of a significant amount of thermoplastic material, this laminate of the invention has the advantage of being weakly hysteretic compared to such conventional fabrics. However, a major goal of tire manufacturers is precisely to lower the hysteresis of their constituents to reduce the rolling resistance of these tires.

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

This diene elastomer is preferably chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), the various butadiene copolymers, the various copolymers of isoprene, and mixtures of these elastomers, such copolymers being chosen in particular from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR) and copolymers of isoprene-butadiene-styrene (SBIR). A particularly preferred embodiment consists in using an "isoprene" elastomer, that is to say a homopolymer or a copolymer of isoprene, in other words a diene elastomer chosen from the group consisting of natural rubber (NR ), the synthetic polyisoprenes (IR), the various isoprene copolymers and the mixtures of these elastomers. The isoprene elastomer is preferably natural rubber or synthetic polyisoprene of the cis-1,4 type. Among these synthetic polyisoprenes, polyisoprenes having a content (mol%) of cis-1,4 bonds greater than 90%, more preferably still greater than 98%, are preferably used. According to a preferred embodiment, each layer of rubber composition comprises 50 to 100 phr of natural rubber. According to other preferred embodiments, the diene elastomer may consist, in whole or in part, of another diene elastomer such as, for example, an SBR elastomer used in or with another elastomer, for example type BR.

The rubber composition may contain one or more diene elastomer (s), this last one (s) may be used in combination with any type of synthetic elastomer other than diene, or even with polymers other than elastomers. The rubber composition may also comprise all or part of the additives normally used in rubber matrices intended for the manufacture of tires, such as, for example, reinforcing fillers such as carbon black or silica, coupling agents, anti-blocking agents, aging, antioxidants, plasticizing agents or extension oils, whether these are of aromatic or non-aromatic nature, plasticizing resins with high glass transition temperature, processing agents, tackifying resins, anti-eversion agents, methylene acceptors and donors, reinforcing resins, a crosslinking or vulcanization system. Preferably, the crosslinking system of the rubber composition is a so-called vulcanization system, that is to say based on sulfur (or a sulfur-donor agent) and a primary vulcanization accelerator. To this basic vulcanization system may be added various known secondary accelerators or vulcanization activators. The sulfur is used at a preferential rate of between 0.5 and 10 phr, the primary vulcanization accelerator, for example a sulfenamide, is used at a preferential rate of between 0.5 and 10 phr. The level of reinforcing filler, for example carbon black or silica, is preferably greater than 50 phr, especially between 50 and 150 phr.

Carbon blacks are suitable for all carbon blacks, in particular blacks of the HAF, ISAF, SAF type conventionally used in tires (so-called pneumatic grade blacks). Among the latter, mention will be made more particularly of carbon blacks of (ASTM) grade 300, 600 or 700 (for example N326, N330, N347, N375, N683, N772). Suitable silicas are in particular precipitated or pyrogenic silicas having a BET surface area of less than 450 m ² / g, preferably from 30 to 400 m ² / g.

Those skilled in the art will know, in the light of the present description, adjust the formulation of the rubber composition in order to achieve the desired levels of properties (including modulus of elasticity), and adapt the formulation to the application specific consideration. Preferably, the rubber composition has, in the crosslinked state, a secant modulus in extension, at 10% elongation, which is between 4 and 25 MPa, more preferably between 4 and 20 MPa; values in particular between 5 and 15 MPa have proved to be 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 secant modulus is measured in second elongation (that is to say after an accommodation cycle). "true" (that is to say, brought back to the actual section of the test piece) at 10% elongation, noted here Ms and expressed in MPa (normal temperature and humidity conditions according to standard ASTM D 1349 of 1999). According to a preferred embodiment, in the multilayer laminate of the invention, the thermoplastic layer (12) is provided with an adhesive layer with respect to each layer of rubber composition with which it is in contact. To adhere the rubber to this thermoplastic material, it is possible to use any suitable adhesive system, for example a simple textile glue of the "RFL" type (resorcinolformaldehyde latex) comprising at least one diene elastomer such as natural rubber, or any equivalent adhesive known to confer a satisfactory adhesion between rubber and conventional thermoplastic fibers such as polyester or polyamide fibers, for example the adhesive compositions described in applications WO 2013/017421, WO 2013/017422, WO 2013 / 017,423.

By way of example, the sizing process can essentially comprise the following successive steps: passing through a bath of glue, followed by dewatering (for example by blowing, calibrating) in order to eliminate the excess of glue; then drying for example by passing through a heating oven or tunnel (for example for 30 s at 180 ° C) and finally heat treatment (for example for 30 s at 230 ° C). Before the above sizing, it may be advantageous to activate the surface of the thermoplastic material, for example mechanically and / or physically and / or chemically, to improve its adhesion of adhesive and / or its final adhesion to rubber . Mechanical treatment may for example consist of a preliminary step of matting or scratching of the surface; a physical treatment may for example consist of a radiation treatment such as an electron beam; a chemical treatment may for example consist of a prior passage in an epoxy resin bath and / or isocyanate compound.

Since the surface of the thermoplastic material is generally smooth, it may also be advantageous to add a thickener to the glue used, in order to improve the total adhesive uptake of the multi-composite reinforcement during its gluing.

Those skilled in the art will readily 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 multilayer laminate of the invention is ensured definitively during the final cure (crosslinking) of the rubber article, in particular bandage, for which the laminate is intended.

It goes without saying that in all the particular examples of the invention previously described and shown schematically in FIGS. 1 to 7, the CVR monobrins, of diameter D _M and of circular cross-section, could be replaced by monobrins in CVR of different shape. , for example with rectangular cross-section (including square) or other (eg oval), D _M then representing by convention the so-called clutter diameter, that is to say the diameter of the circle circumscribing their cross section. 5. EXAMPLES OF CARRYING OUT THE INVENTION

Hereinafter are described examples of manufacture of CVR monobrins suitable for the invention, then multi-composite reinforcements and multilayer laminates according to the invention based on these single strands in CVR, and finally their use as reinforcing elements for bandages. tires.

CVR monobrins suitable for the invention may be prepared according to a process comprising the following main steps: to make a rectilinear arrangement of glass fibers (filaments) and to cause this arrangement in a direction of advancement:

in a vacuum chamber, degassing the arrangement of fibers by the action of the vacuum;

at the outlet of the vacuum chamber, after degassing, passing through a vacuum impregnation chamber so as to impregnate said fiber arrangement with a thermosetting resin or thermosetting resin composition, in the liquid state, to obtain an impregnate containing the filaments of glass and resin;

passing said impregnated through a calibration die having a section of predetermined surface and shape, to impose a form of single-strand (for example a monofilament of round cross section or a ribbon of rectangular cross section);

downstream of the die, in a UV irradiation chamber, polymerizing the resin under the action of UV;

- Then wind up for storage the monobrin thus obtained.

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

It will be recalled in particular that before any impregnation of the fibers, an essential step of degassing the fiber arrangement by the action of the vacuum must be carried out, in particular in order to reinforce the effectiveness of the subsequent impregnation and especially to guarantee the absence of bubbles inside the final composite monofilament.

After passing through the vacuum chamber, the glass filaments enter an impregnation chamber which is totally filled with impregnating resin, thus free of air: it is in this sense that this step can be described as impregnation of "vacuum impregnation". The resin (impregnating resin composition) preferably comprises a sensitive photo-initiator (reagent) with UV radiation above 300 nm, preferably between 300 and 450 nm. This photoinitiator is used at a preferred level of 0.5 to 3%, more preferably 1 to 2.5%. It may also comprise a crosslinking agent, for example at a level of between 5% and 15% (% by weight of impregnating composition).

Preferably, this photoinitiator is of the family of phosphine compounds, more preferably a bis (acyl) phosphine oxide, for example bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide ("Irgacure 819"). from BASF) or a mono (acyl) phosphine oxide (for example "Esacure TPO" from Lamberti), such phosphine compounds that can be used in a mixture with other photoinitiators, for example photoinitiators alpha-hydroxy ketone type such as for example dimethylhydroxyacetophenone (eg "Esacure KL200" from Lamberti) or 1-hydroxycyclohexyl-phenylketone (eg "Esacure KS300" from Lamberti), benzophenones such as 2,4,6-trimethylbenzophenone (eg "Lamberti TZT Esacure") and / or thioxanthone derivatives such as for example isopropylthioxanthone (eg "Lamberti's Esacure ITX").

The so-called "calibration" die makes it possible, by means of a cross-section of determined dimensions, generally and preferably circular or rectangular, to adjust the proportion of resin with respect to the glass fibers while imposing on the impregnated form and 'thickness targeted for the single-core.

The polymerization or UV irradiation chamber then has the function of polymerizing, crosslinking the resin under the action of UV. It comprises one or preferably several UV irradiators, constituted for example each by a UV lamp having a wavelength of 200 to 600 nm.

The CVR monofilament thus formed through the UV irradiation chamber, in which the resin is now in the solid state, is then harvested for example on a receiving coil on which it can be wound over a very great length.

Between the sizing die and the final receiving medium, it is preferred 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, one can for example measure these voltages directly at the output of the irradiation chamber, using appropriate tensiometers well known to those skilled in the art.

In addition to the known steps previously described, the method for manufacturing the CVR monobrin suitable for the invention comprises the following essential steps: the speed (V _Ù -) 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;

the irradiation chamber comprises a UV-transparent tube (such as a quartz tube or preferably a glass tube), referred to as an irradiation tube, through which the monofilament being formed flows, this tube being traversed by a current inert gas, preferably nitrogen.

If these essential steps are not combined, the improved properties of the single strand suitable for the invention, in particular Tgi, elongation A M> and module E M>, can not be reached. In particular, in the absence of a neutral gas sweep such as nitrogen in the irradiation tube, it has been found that the above properties are degraded rather rapidly during manufacture and therefore that the industrial performance does not improve. was more guaranteed.

Moreover, if the irradiation time Di _r of the single strand in the irradiation chamber is too short (less than 1.5 s), numerous tests have revealed (see results of the attached single table, according to tests conducted at different speeds V - greater than 50 m / min) regardless of whether the Tgi values were insufficient, below 190 ° C, or the A _(M ) values were too low, less than 4.0%. It has further been found that a high V irradiation rate (greater than 50 m / min, preferably between 50 and 150 m / min) is favorable on the one hand for an excellent level of alignment of the filaments of glass inside the CVR monofilament, on the other hand to a better maintenance of the vacuum in the vacuum chamber with a clearly reduced risk of seeing a certain impregnating resin fraction of the impregnation chamber return to the chamber empty, and therefore to a better quality of impregnation.

The diameter of the irradiation tube (preferably made of glass) is preferably between 10 and 80 mm, more preferably between 20 and 60 mm. Preferably, the speed V _Ù - is between 50 and 150 m / min, more preferably in a range of 60 to 120 m / min.

Preferably, the irradiation time D _ir is between 1, 5 and 10 s, more preferably in a range of 2 to 5 s. According to another preferred embodiment, the irradiation chamber comprises a plurality of irradiators (or radiators) UV, that is to say at least two (two or more) which are arranged in line around the tube irradiation. Each UV irradiator typically comprises one (at least one) UV lamp (emitting preferably in a spectrum of 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 in-line UV irradiators. Even more preferably, the linear power delivered by each UV irradiator is between 2,500 and 12,000 watts per meter, in particular in a range of 3,000 to 10,000 watts per meter.

UV radiators suitable for the process of the invention are well known to those skilled in the art, for example those marketed by Dr. Hoeil AG (Germany) under the reference "1055 LCP AM UK", equipped with UVAPRINT lamps. (high pressure mercury lamps doped with iron). The nominal power (maximum) of each radiator of this type is equal to about 13,000 Watts, the power actually delivered being adjustable with a potentiometer between 30 and 100% of the nominal power.

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.

According to another preferred embodiment, the irradiation conditions are adjusted in such a way that the temperature of the CVR monobrin 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.

FIG. 8 appended schematizes very simply an example of a device 100 allowing the production of CVR monobrins (10) as schematized in FIG.

It shows a coil 110 containing, in the example shown, glass fibers 111 (in the form of multiflaments). The coil is unwound continuously by driving, so as to achieve a rectilinear arrangement 112 of these fibers 111. In general, the reinforcing fibers are delivered in "rovings", that is to say already in groups of fibers wound in parallel on a coil ; for example, using fibers marketed by Owens Corning under the designation "Advantex" fiber, with a title equal to 1200 tex (as a reminder, 1 tex corresponds to 1 g / 1000 m of fiber). This is for example the traction exerted by the rotary reception 126 which will allow the advancement of the fibers in parallel and the CVR monobrin all along the installation 100. 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 onto an impregnation chamber 114, the two pipes preferably to rigid wall having for example a minimum upper section (typically twice as much) to the total fiber section and a much greater length (typically 50 times more) to said minimum section.

As already taught by the above-mentioned application EP-A-1 174 250, the use of rigid wall pipes, both for the inlet port in the vacuum chamber and for the outlet orifice of the vacuum chamber. and the transfer from the vacuum chamber to the impregnation chamber, is compatible both with high rates of passage of the fibers through the orifices without breaking the fibers, but also ensures a sufficient seal . It suffices, if necessary experimentally, to search for the largest section of passage, taking into account the total section of the fibers to be treated, again making it possible to provide sufficient sealing, taking into account the speed of advance of the fibers and the length tubing. Typically, the vacuum inside the chamber 113 is for example of the order of 0.1 bar, the length of the vacuum chamber is about 1 meter. At the outlet of the vacuum chamber 113 and the outlet pipe 113b, the arrangement 112 of fibers 111 passes through an impregnation chamber 1 14 comprising a feed tank 115 (connected to a metering pump not shown) and a reservoir impregnation impregnation 116 completely filled with impregnating composition 117 based on a curable resin vinylester type (eg, "E-Nova FW 2045" from DSM). By way of example, the composition 117 further comprises (at a weight ratio of 1 to 2%) a photoinitiator suitable for the UV and / or UV-visible radiation by which the composition will subsequently be treated, for example bis- (2,4,6-trimethylbenzoyl) -phenylphosphine oxide ("Irgacure 819" from BASF). It may also comprise (for example about 5% to 15%) of a crosslinking agent such as, for example, tris (2-hydroxyethyl) isocyanurate triacrylate ("SR 368" from Sartomer). Of course, the impregnating composition 117 is in the liquid state.

Preferably, the length of the impregnation chamber is several meters, for example between 2 and 10 m, in particular between 3 and 5 m. Thus, from impregnation chamber 114, in an impervious outlet pipe 118 (always under primary vacuum), an impregnated material which comprises for example (% by weight) from 65 to 75% of solid fibers 111, the rest (25%) 35%) being constituted by the liquid impregnation matrix 117. The impregnated material then passes through calibration means 119 comprising at least one calibration die 120 whose channel (not shown here), for example of circular, rectangular or conical shape, is adapted to the particular conditions of production. By way of example, this channel has a minimum cross section of circular shape whose downstream orifice has a diameter slightly greater than that of the targeted single-core. The die has a length that is typically greater than at least 100 times the minimum dimension of the minimum section. Its function is to ensure a high dimensional accuracy to the finished product, it can also play a role of dosing the fiber ratio with respect to the resin. According to a possible variant embodiment, the die 120 can be directly integrated with the impregnation chamber 114, which avoids, for example, the use of the outlet pipe 118.

Preferably, the length of the calibration zone is several centimeters, for example between 5 and 50 cm, in particular between 5 and 20 cm. Thanks to the calibration means (119, 120) is obtained at this stage a "liquid" composite monofilament (121), liquid in the sense that its impregnating resin is at this stage always liquid, the shape of the cross section is preferentially essentially circular.

At the outlet of the calibration means (119, 120), the liquid composite monofilament (121) thus obtained is then polymerized by passing through a UV irradiation chamber (122) comprising a sealed glass tube (123) through which circulates composite monofilament; said tube, whose diameter is typically a few cm (for example 2 to 3 cm), is irradiated with a plurality (here, for example 4 in number) of UV irradiators (124) in line ("UVAprint" lamps of the company Dr. Hnle, wavelength 200 to 600 nm) arranged at a short distance (a few cm) from the glass tube. Preferably, the length of the irradiation chamber is several meters, for example between 2 and 15 m, in particular between 3 and 10 m. In this example, the irradiation tube 123 is traversed by a stream of nitrogen. The irradiation conditions are preferably adjusted in such a way that, at the outlet of the impregnation chamber, the temperature of the CVR monofilament, measured at 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 150 ° C), and more preferably less than 270 ° C.

Once the resin has polymerized (cured), the CVR (125) solid state, this time in the solid state, driven in the direction of arrow F, then arrives on its final receiving coil (126).

Finally, a finished composite block of manufacture as shown schematically in FIG. 1 is obtained in the form of a continuous CVR monofilament (10), of very great length, whose Unitary glass filaments (101) are evenly distributed throughout the cured resin volume (102). Its diameter is for example equal to about 1 mm. The process described above can be carried out at high speed, preferably greater than 50 m / min, for example between 50 and 150 m / min.

Advantageously, before deposition of the thermoplastic material sheath (12), the resulting CVR monofilament (10) may be subjected to an adhesion treatment in order to improve the subsequent adhesion between the thermoset resin (102) previously described and the thermoplastic sheath (12). A suitable chemical treatment may for example consist of a prior passage in an aqueous bath based on epoxy resin and / or isocyanate compound, followed by at least one heat treatment to remove the water and polymerize the adhesive layer.

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

Once the CVR monobrin (10) 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 even if necessary several parallel strands arranged , through an appropriate extrusion head delivering the thermoplastic material in the molten state.

The cladding or covering step by the thermoplastic material (12) is carried out in a manner known to those skilled in the art. It consists for example simply to pass the or each CVR monofilament through a die or dies of suitable diameter, in extrusion heads heated to appropriate temperatures, or in a coating bath containing the thermoplastic material put beforehand dissolved in a suitable organic solvent (or solvent mixture).

By way of example, the covering of a single-core CVR with a diameter close to 1 mm by a layer of PET with a 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-cladding 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. The PET ("Artenius Design +" from the company Artenius, Tg ₂ equal to about 76 ° C., Tf equal to about 230 ° C.) is melted at a temperature of 280 ° C. in the extruder, thus covering the monofilament in CVR. , through the cladding head, at a thread running speed typically equal to several tens of m / min, for an extrusion pump flow typically of several tens of cm ³ / min. At the outlet of this first cladding, the wire can be immersed in a cooling tank filled with cold water, to solidify and freeze the polyester in its amorphous state, then dried for example in line by an air nozzle, or by passage from the receiving coil to the oven. At the outlet of the extrusion head, the sheath or strands thus sheathed are then cooled sufficiently so as to solidify the layer of thermoplastic material, for example with air or another cold gas, or by passing through a bath of water followed by a drying step.

The multi-composite reinforcement of the invention thus obtained, as schematized 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 is about 1.4 mm; Tgi = about 205 ° C; Tg _{2 is} about 76 ° C; A _(M ) equal to about 4.5%; E _(M ) equal to about 43 GPa; E _(R ) equal to about 14 GPa; E 'I ₉ O ₍ M ₎ equal to about 37 GPa; E _'(Tg i _ ₂₅₎ / E' ₂₀ (M) equal to about 0.92; elastic deformation in flexural compression of the single strand equal to about 3.6%; compressive stress under flexural compression of the single strand equal to about 1350 MPa; weight ratio of glass fibers in the single-core pipe equal to about 70%; initial module in extension of the thermoset vinylester resin, at 20 ° C, equal to about 3.6 GPa; initial modulus in PET extension (at 20 ° C) equal to about 1100 MPa.

The multi-composite reinforcement of the invention thus produced is advantageously usable, especially in the form of a multilayer laminate according to the invention, for reinforcing tires, pneumatic or non-pneumatic, of all types of vehicles, in particular passenger vehicles or industrial vehicles such as heavy vehicles, civil engineering, aircraft, other transport or handling vehicles.

For example, Figure 9 shows very schematically (without respecting a specific scale), a radial section of a tire, whether or not conforming to the invention in this general representation.

This tire 200 has a top 202 reinforced by a crown reinforcement 206, two sidewalls 203 and two beads 204, each of these beads 204 being reinforced with a rod 205. The top 202 is surmounted by a tread represented in this schematic figure. A carcass reinforcement 207 is wrapped around the two rods 205 in each bead 204, the upturn 208 of this armature 207 being for example disposed towards the outside of the tire 200 which is shown here mounted on its rim 209. Of course, this tire 200 also comprises, in a known manner, a layer of rubber 201, commonly known as a rubber or sealing layer, which defines the radially inner face of the tire and which is intended to protect the carcass ply from the diffusion of air from the interior space to the tire.

The carcass reinforcement 207, in the tires of the prior art, generally consists of at least one rubber ply reinforced by "radial" textile or metal reinforcements, that is to say that these reinforcements are disposed substantially parallel to each other and extend from one bead to the other so as to form an angle of between 80 ° and 90 ° with the median circumferential plane (plane perpendicular to the axis of rotation of the tire which is located halfway between the two beads 204 and passes through the middle of the crown reinforcement 206). The belt 206 is for example constituted, in the tires of the prior art, by at least two layers of rubber called "working plies" or "triangulation plies", superimposed and crossed, reinforced with metal cables arranged substantially parallel to each other. relative to the others and inclined relative to the median circumferential plane, these working plies may or may not be associated with other plies and / or fabrics of rubber. These working plies have the primary function of giving the tire a high rigidity of drift. The belt 206 may furthermore comprise, in this example, a rubber sheet called a "hooping sheet" reinforced by so-called "circumferential" reinforcing threads, that is to say that these reinforcing threads are arranged substantially parallel to each other. other and extend substantially circumferentially around the tire so as to form an angle preferably within a range of 0 to 10 ° with the medial circumferential plane. These circumferential reinforcing threads have the particular function of resisting the centrifugation of the top at high speed. A pneumatic tire 200, when in accordance with the invention, has the preferred feature that at least its belt (206) and / or its carcass reinforcement (207) comprises a multilayer laminate according to the invention, consisting of at least one multi-composite reinforcement according to the invention arranged between and in contact with two layers of diene rubber composition. According to a particular embodiment of the invention, this multi-composite reinforcement of the invention can be used in the form of parallel sections disposed under the tread, as described in the aforementioned EP 1,167,080 patent. According to another possible embodiment of the invention, it is the bead zone which can be reinforced with such a multi-composite reinforcement; it is for example the rods (5) which could consist, in whole or in part, of a multi-composite reinforcement according to the invention. In these examples of FIG. 9, the rubber compositions used for the multilayer laminates according to the invention are, for example, conventional compositions for calendering textile reinforcements, typically based on natural rubber, carbon black or silica, vulcanization system and usual additives. Thanks to the invention, compared to rubber compositions reinforced with steel cables, they may advantageously be free of metal salt such as a cobalt salt. The adhesion between the multi-composite reinforcement of the invention and the rubber layer which encapsulates it can be ensured in a simple and known manner, for example by a conventional RFL-type glue (resorcinolformol-latex), or using more recent glues as described for example in the aforementioned applications WO 2013/017421, WO 2013/017422, WO 2013/017423.

Particular tests in pneumatic tires have been carried out, where multi-composite reinforcements according to the invention as previously manufactured have been used as elongated reinforcements, that is to say non-cabled, in crossed working plies instead. conventional steel cables, as described in the aforementioned document EP 1 167 080.

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

While noticeably lightening the tires and eliminating the risks related to corrosion, compared to bandages whose belt is conventionally reinforced with steel cables, the multi-composite reinforcements of the invention have also revealed another notable advantage that not to increase the rolling noise of tires, unlike other known textile solutions (reinforcements).

These multi-composite reinforcements of the invention have also shown excellent performance as circumferential reinforcements in non-pneumatic type tires as described in the introduction to this specification.

In conclusion, the advantages of the multilayer laminate and the multi-composite reinforcement of the invention are numerous (low thickness, low density, low cost, insensitivity to corrosion) compared to conventional metal fabrics, and the results obtained thanks to the of the invention (in particular improved compression properties) open up a very large number of possible applications, in particular as a reinforcing element for the tire belt, arranged between the tread and the carcass reinforcement of such bandages. Board

Claims

1. Multi-composite reinforcement (R1, R2) comprising one or more glass-resin composite monofilaments (10) (abbreviated as "CVR") comprising glass filaments (101) embedded in a thermoset resin (102) whose glass transition temperature is denoted Tgi, characterized in that:

a layer of a thermoplastic material (12) covers said single strand or, if they are several, individually each single strand or collectively all or at least a part of the strands;

said single strand or, if there is more than one, all or at least some of the strands has the following characteristics:

a temperature Tgi equal to or greater than 190 ° C .;

an elongation at break noted A _(M) , measured at 20 ° C., equal to or greater than 4.0%; and

an initial module in extension denoted E _(M) , measured at 20 ° C., greater than 35 GPa.

2. Multi-composite reinforcement according to claim 1, wherein Tgi is greater than 195 ° C, preferably greater than 200 ° C.

3. Multi-composite reinforcement according to claims 1 or 2, wherein the glass transition temperature denoted Tg ₂ of the thermoplastic material is greater than -30 ° C, preferably greater than 20 ° C.

4. Multi-composite reinforcement according to claim 3, wherein Tg ₂ is greater than 50 ° C, preferably greater than 70 ° C.

5. Multi-composite reinforcement according to any one of claims 1 to 4, wherein A (M) is greater than 4.2%, preferably greater than 4.4%.

6. Multi-composite reinforcement according to any one of claims 1 to 5, wherein E (M) is greater than 40 GPa, preferably greater than 42 GPa.

7. multi-composite reinforcement according to any one of claims 1 to 6, wherein said single-core or, if they are several, all or at least part of the single-strand has a real part of the complex module noted ΕΊ _9Ο ( _Μ ), measured at 190 ° C by the DTMA method, which is greater than 30 GPa.

8. A multi-composite reinforcement according to any one of claims 1 to 7, wherein said single-core or, if they are several, all or at least a part of them has an elastic deformation in flexural compression which is greater than 3.0%, preferably greater than 3.5%.

9. A multi-composite reinforcement according to any one of claims 1 to 8, wherein said single-core or, if they are several, all or at least a part of them has a tensile stress in flexural compression which is greater than 1000 MPa, preferably greater than 1200 MPa.

A multi-composite reinforcement according to any one of claims 1 to 9, wherein the thermoset resin (102) of said single strand, or, if they are more than one, all or at least a portion of the single strands, is a polyester or vinylester resin, preferably vinylester.

11. Multi-composite reinforcement according to any one of claims 1 to 10, wherein the thermoset resin (102) of said single-core or, if they are several, all or at least a portion of the single strands, has a initial module in extension, measured at 20 ° C, which is greater than 3.0 GPa, preferably greater than 3.5 GPa.

12. Multi-composite reinforcement according to any one of claims 1 to 11, wherein the diameter denoted D _{M of} said single-core or each single-strand if they are several is between 0.2 and 2.0 mm, preferably between 0.3 and 1.5 mm.

13. multi-composite reinforcement according to any one of claims 1 to 12, wherein the minimum thickness denoted E _m of the layer of thermoplastic material covering said single-core or each single strand if they are more, is between 0.05 and 0.5 mm, preferably between 0.1 and 0.4 mm.

14. A multi-composite reinforcement according to any one of claims 1 to 13, wherein the thermoplastic material is a polymer or a polymer composition.

The multi-composite reinforcement according to claim 14, wherein the polymer is selected from the group consisting of polyamides, polyesters, polyimides and mixtures of such polymers, preferably from the group consisting of polyesters, polyetherimides and mixtures of such polymers.

16. multi-composite reinforcement according to any one of claims 1 to 15, wherein the initial modulus in extension of the thermoplastic material, measured at 20 ° C, is between 300 and 3000 MPa, preferably between 500 and 2500 MPa .

17. Multi-composite reinforcement according to claim 16, wherein the initial modulus in extension of the thermoplastic material, measured at 20 ° C, is between 500 and 1500 MPa.

18. Multi-composite reinforcement according to any one of claims 1 to 17, wherein the elastic elongation of the thermoplastic material, measured at 20 ° C, is greater than 5%, preferably greater than 8%.

19. Multi-composite reinforcement according to any one of claims 1 to 18, wherein the elongation at break of the thermoplastic material, measured at 20 ° C, is greater than 10%, preferably greater than 15%.

20. Multi-composite reinforcement according to any one of claims 1 to 19, whose elongation at break noted A _(R) , measured at 20 ° C, is equal to or greater than 3.0%, preferably equal to or greater than 3.5%.

21. Multi-composite reinforcement according to any one of claims 1 to 20, whose initial modulus in extension noted E _(R ), measured at 20 ° C, is greater than 9 GPa, preferably greater than 12 GPa.

22. Multilayer laminate comprising at least one multi-composite reinforcement according to any one of claims 1 to 21, disposed between and in contact with two layers of rubber composition.

23. A finished article or semi-finished product made of plastic or rubber comprising a multi-composite reinforcement according to any one of claims 1 to 21 or a multilayer laminate according to claim 22.

Pneumatic or non-pneumatic tire, comprising a multi-composite reinforcement according to any one of claims 1 to 21 or a multilayer laminate according to claim 22.

A bandage according to claim 24, wherein the multi-composite reinforcement or multilayer laminate is present in the tire belt or in the carcass reinforcement of the tire.

Bandage according to claim 24, wherein the multi-composite reinforcement or the multilayer laminate is present in the bandage zone of the bandage.

27. Use of a reinforcement according to any one of claims 1 to 21, or a multilayer laminate according to claim 22, as a reinforcing element of an article or semi-finished product of plastic or rubber.