BR112017025585B1 - MULTI-COMPOSITE REINFORCEMENT MADE OF IMPROVED GLASS-RESIN - Google Patents

Abstract

multicomposite reinforcement made from improved resin glass. multicomposite reinforcement (r1, r2) comprising one or more monofilament(s) (10) made of glass-resin composite comprising glass filaments (101) embedded within a thermoset resin (102) of glass transition temperature tg1, characterized by the fact that: - a layer of a thermoplastic material (12) covers said monofilament or, if there are several of them, individually each monofilament or collectively the entirety or at least a part of the monofilaments; - said monofilament or, if there are several of them, all or at least part of the monofilaments has the following characteristics: - a tg1 temperature equal to or greater than 190ºc; - an elongation at break a(m) equal to or greater than 4.0%; - an initial module in extension e(m) greater than 35 gpa. belt, pneumatic or non-pneumatic, reinforced by such multi-composite or multi-layer laminated reinforcement.

Description

FIELD OF THE INVENTION

[001] 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 made of rubber such as vehicle belts, of the pneumatic or non-pneumatic type.

[002] It refers more especially to composite reinforcements based on monofilaments of the type made of “CVR” (short for Composite Glass-Resin) of high mechanical and thermal properties, which comprise continuous, unidirectional, multifilament glass fibers embedded in a thermoset resin and usable in particular as reinforcing elements for these straps.

STATUS OF THE TECHNIQUE

[003] The designers of straps have been looking for a long time for “reinforcements” (longilinear reinforcing elements) of the textile or composite type, of low density, which can be advantageously and effectively substituted for conventional metallic wires or cables, taking into account with a view to significantly reducing the weight of these belts and also correcting any corrosion problems.

[004] Thus, the patent EP 1 167 080 (or US 7 032 637) has already described a monofilament made of "CVR", of high mechanical properties, which comprises continuous, unidirectional glass fibers, impregnated inside a crosslinked resin of the type vinylester. This monofilament presents, in addition to a high compressive rupture stress, higher than its extension rupture tension, an elongation at rupture of the order of 3.0 to 3.5% and an initial modulus in extension of at least 30 GPa; its thermoset resin has a TG (glass transition temperature) above 130°C and an initial modulus in extension of at least 3 GPa.

[005] Thanks to the above properties, that patent EP 1 167 080 showed that it was advantageously possible to replace steel cables with such monofilaments made of CVR, arranged in particular under the tread in parallel segments, as new reinforcing elements of pneumatic belts, which make it possible to significantly lighten the structure of the tires.

[006] It was found, however, unexpectedly, that these composite monofilaments of the prior art, when they were used as belt reinforcements of certain pneumatic belts, could be subjected to a certain number of breaks in compression, by collapsing or buckling. of the structure thereof, during the actual manufacture of these belts, in particular during the forming stage and/or the final stage of baking in mold of these belts, which is known to be carried out under high pressure and at a very high temperature, typically higher at 160°C.

[007] This is how the Applicants, in the recently published patent application WO 2015/014578, have already proposed a monofilament made of new CVR with improved Tg, elongation at break and modulus properties, which give the latter properties in compression , especially under high temperature, which are remarkably improved over those of the prior art CVR monofilaments described in the cited application EP 1 167 080, and which allow the aforementioned problem to be corrected.

[008] Experience shows, however, that the composite monofilaments described in the patent documents described above can be further improved, more especially for their use in pneumatic or non-pneumatic belts for vehicles.

BRIEF DESCRIPTION OF THE INVENTION

[009] Continuing their research, the Applicants discovered a new reinforcement, based on monofilaments made of CVR, whose properties in compression, bending or under transverse shear are remarkably improved over those of the composite monofilaments of the prior art.

[0010] Thus, according to a first object, the present invention relates (referring to the attached figures 1 and 2) to a multicomposite reinforcement (R1, R2) comprising one or more monofilament(s) (10) made of glass-resin composite comprising glass filaments (101) embedded within a thermosetting resin (102) whose glass transition temperature is noted Tg1, said multicomposite reinforcement being characterized by the fact that: - a layer of a thermoplastic material (12) ) covers said monofilament or, if they are several, individually each monofilament or collectively all or at least a part of the monofilaments; - said monofilament or, if there are several, all or at least a part of the monofilaments has the following characteristics: - a temperature Tgi equal to or greater than 190°C; - an elongation at break annotated A(M), measured at 20°C, equal to or greater than 4.0%; - an initial module in extension annotated E(M), measured at 20°C, greater than 35 GPa.

[0011] The thermoplastic and therefore thermofusible character of the material that covers the monofilaments made of CVR allows, on the other hand, quite advantageously, to manufacture in a certain way by “gluing or thermal bonding” a wide variety of multicomposite reinforcements (with several filaments) that have different shapes and cross-sections, by at least partial melting of the covering material, and then cooling the set of filaments coated with thermoplastic material, once the latter are arranged together, arranged in an appropriate manner.

[0012] The invention also relates to any multi-layer laminate that comprises at least one multi-composite reinforcement according to the invention, arranged between and in contact with two layers of rubber composition, notably dienic rubber.

[0013] The invention also relates to any finished article or semi-finished product made of plastics material or made of rubber which comprises a multi-composite reinforcement or a multi-layer laminate according to the invention. More especially, the invention relates to a belt, pneumatic or non-pneumatic, the multi-composite reinforcement or the multi-layer laminate being present in the band of the belt or in the carcass reinforcement of the belt, or in the bead region of the belt.

[0014] The invention also relates to the use of a multi-composite or multi-layer laminated reinforcement according to the invention, as a reinforcing element for finished articles or semi-finished products made of plastics or rubber defects such as tubes, belts, conveyor belts, belts, pneumatic or non-pneumatic, for vehicles, as well as these articles themselves, semi-finished products and belts, both in the raw state (that is to say before cooking or vulcanization) and in the cooked state (after cooking).

[0015] The belts of the invention, in particular, can be intended for motor vehicles of the tourist type, 4x4, “SUV” (Sport Utility Vehicles), but also for industrial vehicles chosen among pickup trucks, “Heavy vehicles” - ie, subway , buses, road transport equipment (trucks, tractors, trailers), off-road vehicles -, agricultural or civil engineering equipment, airplanes, transport or maintenance utility vehicles.

[0016] The multi-composite reinforcement and the multi-layer laminate of the invention are more especially usable as reinforcing elements in top reinforcements (or straps) or in strap carcass reinforcements, as described notably in EP 1 167 080 or US 7 032 637 valued. They could also be present in the bead zone of such straps.

[0017] The multicomposite reinforcement of the invention is also advantageously usable, due to its low density and its properties in compression, bending and under transverse shear which are improved, as reinforcement elements in belts or flexible wheels of the non-pneumatic type, either say structurally supported (no internal pressure). Such belts or wheels are well known to the person 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 rigid mechanical element intended to ensure the connection between the flexible belt and the hub of a wheel, they replace the set consisting of the pneumatic belt, the rim and the disc as they are known in most road vehicles current. The multi-composite reinforcement of the invention is particularly advantageously usable in the shear layer which forms the band of such belts.

[0018] The invention as well as its advantages will be easily understood in the light of the detailed description and the examples of implementation that follow, as well as the figures 1 to 9 relating to these examples which schematize (without respecting a specific scale): - in cross-section, a monofilament (1) made of CVR usable in a multicomposite reinforcement according to the invention (Fig. 1); - 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 multicomposite reinforcement according to the invention (Fig. 3); - in cross-section, another example (R-4) of multicomposite reinforcement according to the invention (Fig. 4); - in cross section, another example (R-5) of multicomposite reinforcement according to the invention (Fig. 5); - in cross-section, another example (R-6) of multicomposite reinforcement according to the invention (Fig. 6); - in cross-section, an example (20) of a multi-layer laminate according to the invention comprising a multi-composite reinforcement according to the invention (R-7) itself embedded in a dienic rubber matrix (Fig. 7); - a device usable for manufacturing a monofilament (10) made of CVR usable as a basic constitutive element of a multicomposite reinforcement according to the invention (Fig. 8); - in radial section, an example of a pneumatic belt according to the invention, which incorporates a multi-composite reinforcement and a multi-layer laminate according to the invention (Fig. 9).

DETAILED DESCRIPTION OF THE INVENTION

[0019] In the present application, unless expressly stated otherwise, all percentages (%) indicated are percentages by mass.

[0020] Every range of values designated by the expression “between a and b” represents the range of values that goes from more than a to less than b (meaning limits a and b excluded) while every interval of values designated by the expression “from aab” means the domain of values that goes from a to b (that is, it includes the strict limits a and b).

[0021] Unless expressly stated otherwise, all mechanical properties in extension or in compression are measured (in monofilament, thermoset resin, or even thermoplastic material) at a temperature of 20°C.

[0022] The invention therefore relates to a reinforcement of the multicomposite type, in other words a composite composite, usable in particular for the reinforcement of articles made of rubber such as belts for vehicles, whose essential characteristic is to comprise at least, firstly, a monofilament or several monofilaments (1) made of glass-resin composite (in abbreviated “CVR”) such as schematized in Figure 1, comprising glass filaments (101) embedded within a thermosetting resin (102) of which the transition temperature vitreous, the said monofilament or, if there are several, all or at least a part of the monofilaments, having the following essential characteristics: - a temperature Tgi equal to or greater than 190°C is noted as Tg1; - an elongation at break A(M), measured at 20°C, equal to or greater than 4.0%; and - an initial module in ECM extension), measured at 20°C, greater than 35 GPa.

[0023] Typically the glass filaments are present in the form of a single multifilament fiber or several multifilament fibers (if they are several, they are preferably essentially unidirectional), each of which may comprise several tens, hundreds and even thousands of fibers. single glass filaments. Such very fine unitary filaments generally and preferably have an average diameter of the order of 5 to 30 µm, more preferably 10 to 20 µm.

[0024] By "resin" or "thermoset resin" is understood herein the resin as such and any composition based on that resin and which comprises at least one additive (that is to say one or more additives). This resin is obviously cross-linked (for example photo-hardened and/or heat-cured), in other words in the form of a network of three-dimensional bonds, in a state specific to so-called thermoset polymers (as opposed to so-called thermoplastic polymers).

[0025] The temperature Tgi is preferably above 195°C, more preferably above 200°C. It is measured (as Tg2 and Tf described below) in a manner known as DSC (Differential Scanning Calorimetry), on the second pass, for example, and unless otherwise specified in the present application, in accordance with ASTM D 3418 of 1999 (device Mettler Toledo DSC “822-2”; nitrogen atmosphere; samples previously brought from room temperature (23°C) to 259°C (10°C/min.), then rapidly cooled (quenched) to a preferably lower temperature of at least 50°C at the considered Tg temperature (eg up to 23°C), before final recording of the DSC curing from that quench temperature (eg 23°C) up to 250°C, according to a ramp of 10 °C/min.).

[0026] The elongation at break A(M) of the monofilament or, if there are several, of all or at least a part (preferably most) of the monofilaments, is preferably greater than 4.2%, more preferably greater at 4.4%. The initial modulus in length E(M) of the monofilament or, if there are several, of all or at least a part (preferably most) of the monofilaments, is preferably greater than 40 GPa, more preferably greater than 42 GPa.

[0027] The mechanical properties in extension (module E and elongation at break A) are measured in a known manner with the aid of an “INSTRON” type 4466 traction machine (BLUEHILL-2 software supplied with the traction machine), so in accordance with ASTM D 638, in monofilaments made of CVR or multicomposite reinforcements, raw manufacturing means not sized, or else sized (meaning ready for use), or even in extracts from the semi-finished product or from the article made of rubber that they reinforce. Prior to measurement, these monofilament or multi-composite reinforcements are subjected to preconditioning (storage for at least 24 h in a standard atmosphere in accordance with European standard DIN EN 20139 (temperature 23 ± 2°C; hygrometry of 50 ± 5 % )). The tested samples are subjected to tension over an initial length of 400 mm at a nominal speed of 100 m/min., under a standard pre-tension of 0.5 cN/tex. All results given are an average of 10 measurements.

[0028] 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 annotated E'190(M) of the monofilament or, if they are several, of the all or at least a part (preferably most) of the monofilaments, measured at 190°C by the DTMA method, is greater than 30 GPa, E'190(M) is more preferably greater than 33 GPa, even more preferably greater than 36 GPa.

[0029] According to an especially preferred embodiment, in cases where several monofilaments are present in the multicomposite reinforcement of the invention, each of the monofilaments has essential characteristics of Tg1, A(M) and E(M) as stated above ; more preferably, each exhibits the preferred, notably more preferred, characteristics of Tg1, A(M), E(M) and E'190(M) as stated above.

[0030] According to another preferred embodiment, for an optimized compromise of thermal and mechanical properties of the reinforcement of the invention, the ratio E'(Tg1' - 25(M) / E'20(M) is greater than 0 .85, preferably greater than 0.90; E'20(M) and E'(Tg1' - 25)(M) represent the real part of the complex module of the monofilament, measured by DTMA respectively at 20°C and at a temperature expressed in °C equal to (Tg2' - 25), expression in which Tgi' represents the glass transition temperature (Tg) measured this time by DMTA.

[0031] According to another more preferred embodiment, the ratio E'(Tg1' - 10(M) / E'20(M) is greater than 0.80, preferably greater than 0.85, E' (Tg1' - 10(M) being the real part of the complex module of the monofilament measured by DTMA at a temperature in °C equal to (Tg1' - 10).

[0032] The measurements of E' and Tg1' are carried out in a way known as DTMA (Dynamic Mechanical Thermal Analysis), with a viscosity analyzer “DMA+ 450” from ACOEM (France), which uses the software “Dynatest 6.83 / 2010 ” that commands bending, tensile or torsional tests.

[0033] According to this device, the three-point bending test does not allow in a known way to enter the initial geometric data for a monofilament of circular section, it is only possible to enter the geometry of a rectangular (or square) section. In order to obtain an accurate measurement of the modulus E' for a monofilament of diameter denoted here DM (see Fig. 10, therefore, by convention, a square section of side “a” which has the same surface moment of inertia is introduced into the software by convention). , this in order to work at the same stiffness R of the tested specimens.

[0034] The following well-known relationships must be applied (E being the modulus of the material, Is the surface moment of inertia of the considered body, and * the multiplication symbol):

[0035] The value of side “a” of the square equivalent of the same surface inertia as that of the (circular) section of the monofilament of diameter D is easily deduced from this, according to the equation:

[0036] In the case where the cross section of the tested sample is not circular (nor rectangular), whatever the special shape, the same calculation method will be applied, previously determined for this the surface moment of inertia Is in a straight cut of the sample tested.

[0037] The specimen to be tested, generally of circular section and diameter DM, 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 specimen, halfway between the two supports, in the form of a vertical displacement of amplitude equal to 0.1 mm (thus asymmetrical deformation, the interior of the specimen being only requested in compression and not in compression), at a frequency of 10 Hz.

[0038] The following program is then applied: under this dynamic load, the specimen is progressively heated from 25°C to 260°C with a ramp of 2°C/min. At the end of the test, the elastic modulus E', the viscous modulus E'' and the loss angle (δ) as a function of temperature are obtained (where E' is the real part and E'' the imaginary part of the complex modulus ); Tg1' is the glass transition temperature that corresponds to the maximum (peak) of tan(δ).

[0039] According to a preferred embodiment, the monofilament made of CVR or, if there are several, all or at least a part (preferably the majority) of the monofilaments made of CVR, presents an elastic deformation in compression under flexure which is greater than 3.0%, more preferably greater than 3.5%, especially greater than 4.0%; according to another preferred embodiment, the tensile strength in compression under bending thereof is greater than 1000 MPa, more preferably greater than 1200 MPa, in particular greater than 1400 MPa.

[0040] The above properties in compression under bending are measured on monofilaments made of CVR as described in the aforementioned 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 progressively raised to the breaking point. The nature of the rupture, easily observable due to the large size of the section, allows us to immediately perceive that the monofilament, when flexed until rupture, breaks on the side on which the material is in extension, which is identified by simple observation. Since in this case the dimensions of the loop are large, it is possible at any time to read the radius of the circle inscribed within the loop. The radius of the circle inscribed just before the breaking point corresponds to the critical radius of curvature, designated by Rc.

[0041] The following formula then allows the calculation of the annotated critical elastic strain Ec (where r corresponds to the radius of the monofilament, that is DM/2) to be determined:

[0042] The failure stress in compression under bending annotated c is obtained by calculating the following formula (where E is the initial modulus in extension):

[0043] When the breakage of the loop appears in the part in extension, it is possible to conclude from this that, in bending, the breaking stress in compression is superior to the breaking stress in extension.

[0044] It is also possible to proceed with the bending failure of a rectangular bar according to the so-called three-point method (ASTM D 790). This method also makes it possible to visually verify that the nature of the rupture is even in extension.

[0045] According to a preferred embodiment, the tensile strength 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 monofilament made of CVR under compression, this quantity is measured according to the method described in the publication “Critical compressive stress for continuous fiber unidectional composites” by Thompson et al., Journal of Composite Materials, 46 (26), 3231-3245.

[0046] Preferably, in each monofilament made of CVR or, if they are several, all or at least a part (preferably most) of the monofilaments made of CVR, the alignment rate of the glass filaments is such that more 85% (% by number) of the filaments have an inclination with respect to the monofilament axis that is less than 2.0 degrees, more preferably less than 1.5 degrees, that inclination (or misalignment) being measured as described in above publication by Thompson et al.

[0047] Preferably, in the multicomposite reinforcement of the invention, the monofilament made of CVR or, if there are several, all or at least a part (preferably the majority) of the monofilaments made of CVR has a weight ratio of glass filaments that is comprised between 60 and 80%, more preferably between 65 and 75%.

[0048] This weight ratio is calculated by making the ratio of the initial fiberglass titer to the titer of the monofilament made from final CVR. The titer (or linear density) is determined on at least three samples, each corresponding to a length of 50 m, by weighing that length; the title is given in tex (weight in grams of 1000 m of product - as a reminder, 0.111 tex is equivalent to 1 denier).

[0049] According to another preferred embodiment, in the multicomposite reinforcement of the invention, the monofilament made of CVR or, if there are several, all or at least a part (preferably the majority) of the monofilaments made of CVR presents a density (or density in g/cm3) which is comprised between 1.8 and 2.1. It is measured (at 23°C) using a specialized balance from the company Mettler Toledo, type “PG503 DeltaRange”; the samples, of a few cm, are successively weighed in air and dipped in ethanol; the instrument software then determines the average density of the three measurements.

[0050] The annotated diameter DM of the monofilament made of CVR, or of each monofilament made of CVR if they are several, is preferably comprised between 0.2 and 2.0 mm, more preferably between 0.3 and 1.5 mm .

[0051] This definition covers both monofilaments of essentially cylindrical shape (of circular cross section) and monofilaments of different shape, for example oblong monofilaments (of more or less flattened shape) or of rectangular cross section. In the case of a non-circular section and unless otherwise specified, EM is by convention the so-called volume diameter, that is to say the diameter of the imaginary cylinder of revolution that surrounds the monofilament, in other words the diameter of the circumscribed circle that surrounds its straight section. .

[0052] Resin is by definition a crosslinkable (ie, hardenable) resin capable of being crosslinked, cured by any known method, in particular by UV (or UV-visible) radiation, preferably emitting within a spectrum ranging at least from 3000 nm to 450 nm.

[0053] As a crosslinkable resin, a polyester or vinylester resin is preferably used, more preferably a vinylester resin. By "polyester" resin, a resin of the unsaturated polyester type is understood in a known manner. Vinyl ester resins are, for their part, well known in the field of composite materials.

[0054] Without this definition being limiting, the vinyl ester resin is preferably of the epoxyvinyl ester type. More preferably a vinylester resin, notably of the epoxy type, which is at least partially based (that is, grafted onto a structure of the type) novolac (also called phenoplastic) and/or bisphenolic, or preferably a novolac based vinylester resin is used. , bisphenolic or novolac and bisphenolic.

[0055] Preferably, the initial stretch modulus of the resin once it has been thermoset (crosslinked), measured at 23°C, is greater than 3.0 GPa, more preferably greater than 3.5 GPa.

[0056] A novolac-based epoxyvinyl ester resin (part in square brackets in formula I below) responds, for example, in a known manner, to the following formula (I):

[0057] An epoxyvinyl ester resin with a bisphenolic base A (part between square brackets in formula (II) below) responds, for example, to the formula (the “A” remembering that the product is manufactured with the aid of acetone):

[0058] A novolac and bisphenolic epoxyvinyl ester resin showed excellent results. As an example of such a resin, mention may be made of the vinylester resins "ATLAC 590" and "E-Nova FW 2045" from the company DSM (diluted with about 40 5 of styrene) described, for example, in applications EP-A- 1 074 369 and EP-A-1 174 250. Epoxyvinyl ester resins are available from other manufacturers such as for example AOC (USA - “VIPEL” resins).

[0059] According to another essential feature of the invention, as already indicated, a layer of a thermoplastic material (12) covers the monofilament made of CVR or, if there are several, each monofilament individually or collectively the entirety or at least one part (preferably the majority) of the monofilaments, to constitute the multicomposite reinforcement of the invention.

[0060] It was found that the presence of this sheath, a layer of thermoplastic material, conferred to the monofilaments made of CVR and, therefore, to the multicomposite reinforcement of the invention, resistance properties in compression, bending or under transverse shear (perpendicularly to the axis of the monofilament) that are remarkably improved, especially at elevated temperature, over those of prior art CVR-made monofilaments.

[0061] The annotated glass transition temperature Tg 2 of that thermoplastic material (12) is preferably greater than -30°C, more preferably greater than 20°C; it is even more preferably above 50°C, in particular above 70°C. Its melting temperature (noted Tf) is preferably above 100°C, more preferably above 150°C, even more preferably above 200°C.

[0062] Preferably, the minimum thickness (noted Em) as schematized for example in Figure 2, of the layer of thermoplastic material that covers the monofilament or each monofilament if they are several, is comprised between 0.05 and 0.5 mm , more preferably between 0.1 and 0.4 mm, especially between 0.1 and 0.3 mm.

[0063] Preferably, the initial modulus in extension of that thermoplastic material (12) is comprised between 300 and 3000 MPa, more preferably between 500 and 2500 MPa, even more preferably between 500 and 1500 MPa; its elastic elongation is preferably greater than 5%, more preferably greater than 8%, especially greater than 10%; its elongation at break is preferably greater than 10%, more preferably greater than 15%, in particular greater than 20%.

[0064] Typically, the thermoplastic material is a polymer or a polymeric composition (that is, a composition based on at least one polymer and at least one additive).

[0065] This thermoplastic polymer is preferably chosen from the group consisting of polyamides, polyesters, polyimides and mixtures of such polymers, more especially from the group consisting of polyesters, polyetherimides and mixtures of such polymers.

[0066] Among the aliphatic polyamides, polyamides 4-6, 6, 6-6, 11 or 12 can be mentioned in particular. The thermoplastic polymer is preferably a polyester; Among the polyesters, mention may be made more especially 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 the company GE Plastics.

[0067] To the above polymer or mixture of polymers, various additives such as dye, plasticizer, antioxidant or other stabilizer may be added, to form a polymeric composition. It will be possible to advantageously add to the above thermoplastic material compatible components, preferably thermoplastics themselves, capable of favoring adhesion to a dienic rubber matrix, for example TPS elastomers (styrenic thermoplastics) of the installed type, notably epoxidized, as described for example in applications WO 2013/117474 and WO 2013/117475.

[0068] According to a preferred embodiment, the sheath (12) comprises a single thermoplastic material. In a variant, the sheath (120) could, however, comprise several different thermoplastic materials.

[0069] As a thermoplastic polymer, it would also be possible to use thermoplastic elastomers (TPE), notably TPS elastomers, saturated or unsaturated, as described for example in applications WO 2010/105975, WO 2010/136389, WO 2011/012521, WO 2011/015204 , WO 2012/016757 , WO 2012/0383340 , WO 2012/038341 , WO 2012/069346 , WO 2012/104279 , WO 2012/104280 and WO 2012/104281 , or else blends of such non-elastomeric polymers are described above and from such thermoplastic elastomers.

[0070] It will be remembered here that thermoplastic elastomers (e.g. styrenics), with an intermediate structure between thermoplastic polymers and elastomers, are constituted in a known manner by rigid thermoplastic sequences (e.g. polystyrene) linked by flexible elastomer sequences, e.g. polybutadiene, polyisoprene or poly(ethylene/butylene). This is the reason why, in a known manner, TPE or TPS copolymers are generally characterized by the presence of two glass transition peaks, the first peak (the lowest temperature, usually negative) being relative to the elastomer sequence of the copolymer, the second peak (the highest temperature, generally and preferably positive, which corresponds to Tg 2 ) being relative to the thermoplastic part (eg styrene blocks) of the copolymer.

[0071] The annotated elongation at break A<R>, measured at 20°C, of the multicomposite reinforcement of the invention is preferably equal to or greater than 3.0%, more preferably equal to or greater than 3.5%. Its annotated initial modulus in extension E(R), measured at 20°C, is preferably greater than 9 GPa, more preferably greater than 12 GPa.

[0072] Figure 2 schematises, in cross-section, two examples (R-1 and R-2) of multicomposite reinforcements according to the invention, in which a single monofilament made of CVR (10) as described above, for example of diameter DM equal to 1 mm, it was covered by its layer, sheath of thermoplastic material, for example made of polyester such as PET, with a minimum thickness annotated Em (for example equal to about 0.2 mm); in these two examples the cross section of the multicomposite reinforcement is either rectangular (here essentially square) or circular (Fig. 2a and Fig. 2b, respectively).

[0073] The annotated diameter (for Fig. 2a) or thickness (for Fig. 2b) DR of these R-1 and R-2 reinforcements of the invention, equal to DM + 2 Em, is therefore about 1.4 mm in these two examples.

[0074] Thanks to the combined presence of its glass filaments (101), of its thermoset matrix (102) and of the thermoplastic sheath (12) that performs, in a certain way, a function of lining the monofilament made of CVR (10), the reinforcement The multicomposite of the invention (R-1, R-2) is characterized by improved transverse cohesion, high dimensional, mechanical and thermal stability.

[0075] In the case where several monofilaments made of CVR are used, the thermoplastic layer or sheath can be placed individually on each of the monofilaments as illustrated for example in figures 2, 5 and 6, or else collectively placed on several of the monofilaments arranged appropriately, for example aligned according to a main direction, as illustrated for example in figures 3, 4 and 7.

[0076] Figure 3 schematizes, in cross-section, another example of a multicomposite reinforcement (R-3) in which two monofilaments made of CVR (10), of substantially the same diameter (e.g. equal to about 1 mm), were covered together by a sheath of thermoplastic material (12), for example made of polyester such as PET, of minimum thickness Em (for example equal to about 0.25 mm). In these examples, the cross section of the multicomposite reinforcement is rectangular, with a thickness DR equal to DM + 2 Em, or for example of the order of 1.5 mm.

[0077] Figure 4 schematizes, in cross section, or another example of a multicomposite reinforcement (R-4) in which four monofilaments made of CVR (10), of substantially the same diameter (e.g. equal to about 0.5 mm ) were covered by a sheath of thermoplastic material, for example made of polyester such as PET, to form a multi-composite reinforcement of substantially square cross-section, with thickness DR.

[0078] The thermoplastic and therefore thermofusible character of the material (12) that covers each filament (10) made of CVR, allows very advantageously to manufacture by thermal bonding a wide variety of multi-composite reinforcements with several filaments, which have different shapes and straight sections, this by at least partial melting of the covering material, and then cooling the set of filaments (10) coated with thermoplastic material (12) once the latter are arranged together, arranged properly. This at least partial melting will be carried out at a temperature preferably comprised between the melting temperature Tf of the thermoplastic material (12) and the glass transition temperature Tg1 of the thermoset resin (12).

[0079] Thus, figure 5 schematizes, in cross-section, another example of a multicomposite reinforcement (R-5) according to the invention in which two elemental multicomposite reinforcements R-2 as schematized in figure 2 (Fig. 2b) ) were placed in contact, glued, welded together by superficial fusion of the thermoplastic sheath (12) of the same and then a cooling step to obtain this R-5 reinforcement of thickness DR.

[0080] Figure 6 reproduces another example of a multicomposite reinforcement according to the invention in which three R-2 elemental multicomposite reinforcements such as schematized in figure 2 (Fig. 2b) were aligned, placed in contact, and then glued, welded together by superficial fusion of the thermoplastic sheath of the same and then cooling, to obtain another multicomposite reinforcement (R-6) of cross section of thickness DR.

[0081] The invention also relates to a multilayer laminate comprising at least one multicomposite reinforcement according to the invention as described above, arranged between and in contact with two layers of rubber or elastomeric composition, notably dienic.

[0082] In the present application, it is understood in a known way, by: - "layered" or "multilayer layered", in the sense of the international classification of patents: any product that comprises at least two layers, flat or non-planar, which they are in contact with each other, the latter may or may not be linked, connected to each other; the expression “connected” or “connected” should be interpreted broadly to include all means of connection or joining, in particular by gluing; - “dienic” rubber: any elastomer (elastomer alone or a mixture of elastomers) that is derived, at least in part (ie; a homopolymer or a copolymer), from diene monomers, that is, from monomers bearing two carbon-carbon double bonds, whether the latter are conjugated or not.

[0083] Figure 7 represents an example of such a multi-layer laminate (20) comprising a multi-composite reinforcement (R-7), consisting of three monofilaments made of CVR (10a, 10b, 10c) (as schematized in Fig. 1). ) collectively embedded in its thermoplastic sheath (12), this reinforcement according to the invention R-7 being itself coated with a sheath (14) of elastomer, for example diene, to constitute a multilayer stratified according to the invention.

[0084] This lightweight, high-performance multilayer laminate, insensitive to corrosion, makes it possible to advantageously replace conventional plies made of rubber reinforced with steel cables or conventional textile cables in vehicle strapping.

[0085] On the other hand, thanks to the presence of a considerable amount of thermoplastic material, this laminate of the invention has the advantage of being less hysteretic compared to such conventional fabrics. Now, a major objective of pneumatic belt manufacturers is precisely to lower the hysteresis of their constituents to reduce the rolling resistance of these belts.

[0086] Each layer of rubber composition, or below "rubber layer" constitutive of the multilayer stratified of the pneumatic belt of the invention is based on at least one elastomer, preferably diene.

[0087] This dienic elastomer is preferably chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), different butadiene copolymers, different isoprene copolymers, and mixtures of these elastomers, such copolymers being notably chosen from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR) and isoprene-butadiene-styrene copolymers (SBIR). ).

[0088] 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 dienic elastomer chosen from the group consisting of natural rubber (NR), synthetic polyisoprenes ( IR), by the different isoprene copolymers and by the mixtures of these elastomers. The isoprene elastomer is preferably natural rubber or a cis-1,4-type synthetic polyisoprene. Among these synthetic polyisoprenes, polyisoprenes are preferably used which have a rate (mol %) of cis-1,4 linkages greater than 90%, more preferably still greater than 98%. In a preferred embodiment, each layer of rubber composition comprises 50 to 100 pcs of natural rubber. According to other preferred embodiments, the dienic elastomer may consist, in whole or in part, of another dienic elastomer, such as, for example, an SBR elastomer used in admixture or not with another elastomer, for example of the BR

[0089] The rubber composition may contain one or more diene elastomer(s), the latter(s) being able to be used in association with any type of synthetic elastomer other than the diene, and even with polymers other than elastomers. The rubber composition may also comprise all or part of the additives commonly used in rubber matrices intended for the manufacture of tires, such as reinforcing fillers such as carbon black or silica, coupling agents, anti-aging agents, antioxidants, plasticizers or extension oils, whether the latter are aromatic or non-aromatic in nature, high-temperature glass transition plasticizing resins, casting agents, tackifying resins, anti-reversion agents, methylene acceptors and donors, reinforcing resins, a crosslinking system or vulcanization.

[0090] 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. Several known secondary accelerators or vulcanization activators can be added to these base vulcanization systems. Sulfur is used at a preferential rate of between 0.5 and 10 pce, the primary vulcanization accelerator, for example a sulfenamide, is used at a preferential rate of between 0.5 and 10 pce. The rate of reinforcing filler, for example carbon black, or silica, is preferably greater than 50pce, notably between 50 and 150pce.

[0091] All carbon blacks are suitable as carbon blacks, notably the HAF, ISAF, SAF type blacks conventionally used in tires (so-called pneumatic grade blacks). Among the latter, carbon blacks of grade (ASTM) 300, 600 or 700 (for example N326, N330, N347, N375, N683, N772) will be mentioned more especially. Precipitated or fumed silicas which have a BET surface of less than 450 m 2 /g, preferably 30 to 400 m 2 /g, are particularly suitable as silicas.

[0092] The professional will know, in light of the present description, to adjust the formulation of the rubber composition in order to reach the desired levels of properties (notably modulus of elasticity) and adapt the formulation to the specific application considered.

[0093] Preferably, the rubber composition, in the crosslinked state, has a drying modulus in extension, at 10% elongation, which is comprised between 4 and 25 MPa, more preferably between 4 and 20 MPa; values between notably 5 and 15 MPa have proved to be particularly suitable for reinforcing tire belt bands. The modulus measurements are carried out in tension, unless otherwise stated in accordance with ASTM D 412 of 1988 (specimen “C”): the secant modulus “ true” (meaning taken to the actual section of the specimen) at 10 % elongation, noted here Ms and expressed in MPa (normal temperature and hygrometry conditions according to ASTM D 1349 of 1999).

[0094] According to a preferred embodiment, in the multilayer laminate of the invention, the thermoplastic layer (12) is provided with an adhesive layer in relation to each layer of rubber composition with which it is in contact.

[0095] To make the rubber adhere to this thermoplastic material, it will be possible to use any suitable adhesive system, for example a simple textile glue of the "RFL" type (resorcinol-formaldehyde-latex) which comprises at least one dienic elastomer such as rubber natural, or any equivalent glue known to impart satisfactory adhesion between rubber and conventional thermoplastic fibers such as fibers made of polyester or made of polyamide, as for example the adhesive compositions described in applications WO 2013/017421, WO 2013/017422, WO 2013 /017423.

[0096] By way of example, the sizing process can essentially comprise the following successive steps: passage in a glue bath, followed by drying (for example by blowing, sizing) to eliminate excess glue; and 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).

[0097] Prior to 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 glue grip and/or its final adhesion to the rubber. A mechanical treatment may consist, for example, of a previous stage of matting or striation of the surface; a physical treatment may consist, for example, of a treatment by a radiation such as an electron beam; a chemical treatment may, for example, consist of a previous passage into a bath of epoxy resin and/or isocyanate compound.

[0098] The surface of the thermoplastic material being generally smooth, it can also be advantageous to add a thickener to the glue used, in order to improve the total glue grip of the multicomposite reinforcement when it is glued.

[0099] The professional will easily understand that the connection between the thermoplastic polymer layer of the multi-composite reinforcement of the invention and each rubber layer with which it is in contact in the multi-layer laminate of the invention is definitively ensured during the final firing (crosslinking) of the article made of rubber, notably a belt, for which the laminate is intended.

[00100] It goes without saying that in all the special examples of the invention previously described and schematized in Figures 1 to 7, the monofilaments made of CVR, of diameter DM and of circular cross section, could be replaced by monofilaments made of CVR in a different, for example rectangular (including square) or other (for example oval) cross-sections, DM representing in this case by convention the diameter of said volume, that is to say the diameter of the circle that circumscribes their cross-section.

EXAMPLES OF ACHIEVEMENT

[00101] Examples of manufacturing monofilaments made of CVR according to the invention are described below, and after multicomposite reinforcements and multilayer laminates according to the invention based on these monofilaments made of CVR, finally their use as reinforcement elements of pneumatic belts.

[00102] The monofilaments made of CVR according to the invention can be prepared according to a process comprising the following main steps: - making a rectilinear arrangement of glass fibers (filaments) and dragging this arrangement in an advancing direction: - within a vacuum chamber, degassing the fiber array by the action of vacuum; - at the exit of the vacuum chamber, after degassing, passing through a vacuum impregnation chamber in order to impregnate said fiber array with a resin or thermoset resin composition, in liquid state, to obtain an impregnate containing the filaments of glass and resin; - passing said impregnate through a sizing die having a predefined surface section and shape, to impose a monofilament shape thereon (for example a round cross-section monofilament or a rectangular cross-section tape); - downstream of the spinneret, inside a UV radiation chamber, polymerize the resin under the action of UV rays; - and then winding up the monofilament thus obtained for storage.

[00103] All the steps above (arrangement, degassing, impregnation, calibration, polymerization and final winding) are steps known to the professional, as are the materials (multifilament fibers and resin compositions) used; they have, for example, been described in one and/or the other of the cited applications EP-A-1 074 369 and EP-A-1 174 250.

[00104] It will be remembered in particular that before any impregnation of the fibers, an essential step of degassing the arrangement of fibers by the action of vacuum must be carried out, in order notably to reinforce the effectiveness of the subsequent impregnation and above all to guarantee the absence of bubbles in the interior of the final composite monofilament.

[00105] After crossing the vacuum chamber, the filaments made of glass enter an impregnation chamber that is completely filled with impregnation resin, and therefore devoid of air: it is in this sense that it is possible to qualify this stage of “vacuum impregnation” impregnation.

[00106] The impregnating resin (resin composition) preferably comprises a photoinitiator sensitive (reactive) to UV above 300 nm, preferably between 300 and 450 nm. Such a photoinitiator is used at a preferred rate of from 0.5 to 3%, more preferably from 1 to 2.5%. It may also comprise a crosslinking agent, for example at a rate comprised between 5% and 15% (% by weight of impregnation composition).

[00107] Preferably, this photoinitiator is from the family of phosphine compounds, more preferably a bis(acyl)phosphine oxide such as, for example, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide ("Irgacure 819" from company BASF) or a mono(acyl)phosphine oxide (for example “Esacure TPO” from the company Lamberti), such phosphine compounds can be used in mixture with other photoinitiators, for example alpha-hydroxy ketone type photoinitiators such as for example dimethylhydroxyacetophenone (eg "Esacure KS300" from Lamberti), benzophenones such as 2,4,6-trimethylbenzonphenone (eg "Esacure TZT" from Lamberti) and/or thioxanthones derivatives such as isopropylthioxanthone (eg "Esacure ITX" from Lamberti).

[00108] The so-called “calibration” die allows, thanks to a straight section of determined dimensions, generally and preferably circular or rectangular, to adjust the proportion of resin in relation to glass fibers while imposing the shape of the impregnated material. and the target thickness for the monofilament.

[00109] The polymerization or UV radiation chamber then has the function of polymerizing, crosslinking the resin under the action of UV rays. It comprises one or preferably several UV radiators, each consisting, for example, of a UV lamp with a wavelength of 200 to 600 nm.

[00110] The monofilament made of CVR thus formed through the UV radiation chamber, in which the resin is now in a solid state, is then collected, for example, in a receiving coil on which it can be wound to a very large length. .

[00111] Between the sizing die and the final receiving support, it is preferred to keep the stresses suffered 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 voltages directly at the output of the irradiation chamber, with the aid of appropriate tensiometers well known to the professional.

[00112] In addition to the previously described known steps, the process for manufacturing the monofilament made of CVR according to the invention comprises the following essential steps: - the speed (Vir) of passage of the monofilament inside the radiation chamber is greater than 50 m/min.; - the duration time (Dir) of passage of the monofilament inside the radiation chamber is equal to or greater than 1.5 s; - the radiation chamber comprises a UV-transparent tube (such as a tube made of quartz or preferably made of glass), said radiation tube, through which the monofilament circulates in the course of formation, this tube being traversed by a current of inert gas, preferably nitrogen.

[00113] If these essential steps are not combined, the improved properties of the monofilament suitable for the invention, notably Tg1, elongation A(M) and modulus E(M), cannot be achieved.

[00114] In particular, in the absence of sweeping neutral gas such as nitrogen into the radiation tube, it was found that the above properties degraded quite rapidly in the course of manufacturing and therefore that industrial performance was no longer guaranteed.

[00115] On the other hand, if the radiation duration time (Dir on the monofilament inside the radiation chamber is too short (less than 1.5 s), numerous tests have revealed (see the results in the attached single table), according to with tests conducted at different Vir speeds greater than 50 m/min.) that either the Tgi values were insufficient, below 190°C, or the A(M) values were too low, below 4.0%.

[00116] On the other hand, it was found that a high velocity of Vir radiation (above 50 m/min., preferably between 50 and 150 m/min.) was favorable, on the one hand, to an excellent rate of alignment of the filaments of glass inside the monofilament made of CVR, on the other hand to better maintenance of the vacuum inside the vacuum chamber with a markedly reduced risk of seeing a certain fraction of impregnation resin rise from the impregnation chamber to the vacuum chamber, and therefore better impregnation quality.

[00117] The diameter of the radiation tube (preferably made of glass) is preferably comprised between 10 and 80 mm, more preferably between 20 and 60 mm.

[00118] Preferably, the Vir speed is comprised between 50 and 150 m/min., but preferably within a range of 60 to 120 m/min.

[00119] Preferably, the duration time Dir is comprised between 1.5 and 10 s, more preferably within a range of 2 to 5 s.

[00120] According to another preferred embodiment, the radiation chamber comprises a plurality of UV irradiators (or radiators), that is to say at least two (two or more than two) which are arranged in a line around the UV tube. radiation. Each UV radiator typically comprises one (at least one) UV lamp (preferably emitting within a spectrum of 200 to 600 nm) and a parabolic reflector center of which the center of the radiation tube is located; it supplies a linear power preferably comprised between 2000 and 14000 watts per meter. More preferably still, the radiation chamber comprises at least three, in particular at least four UV radiators in a row.

[00121] Even more preferably, the linear power supplied by each UV radiator is comprised between 2,500 and 12,000 watts per meter, especially within a range of 3,000 to 10,000 watts per meter.

[00122] UV radiators suited to the process of the invention are well known to the professional, for example those marketed by the company Dr. Honle AG (Germany) under the reference "1055 LCP AM UK", equipped with "UVAPRINT" lamps (mercury lamps high-pressure iron-doped pump). The nominal (maximum) power of each radiator of this type is equal to approximately 13 000 Watts, the power supplied effectively being able to be regulated with a potentiometer between 30 and 100 % of the nominal power.

[00123] Preferably, the temperature of the resin (resin composition) within the impregnation chamber is between 50°C and 95°C, more preferably between 60°C and 90°C.

[00124] According to another preferred embodiment, the radiation conditions are adjusted in such a way that the temperature of the monofilament made of CVR, at the exit of the impregnation chamber, is higher than the Tg (Tg1) of the crosslinked resin; more preferably, that temperature is above the Tg (Tg1) of the crosslinked resin and below 270°C.

[00125] Figure 8 schematically attaches very simply an example of a device 100 that allows the production of monofilaments made of CVR (10) such as schematized in Figure 1.

[00126] There is seen a coil 110 which, in the illustrated example, contains glass fibers 111 (in the form of multifilaments). The spool is unrolled continuously by driving, so as to make a rectilinear arrangement 112 of these fibers 111. In general, the reinforcing fibers are delivered in "rovings", that is, in groups of fibers wound in parallel on a spool; for example, fibers sold by Owens Corning under the name of “Advantex” fiber are used, with a title equal to 1200 tex (as a reminder, 1 tex corresponds to 1 g/1000 m of fiber). It is, for example, the traction exerted by the swivel reception 126 that will allow the advancement of the parallel fibers and the monofilament made of CVR throughout the entire installation 100.

[00127] This arrangement 112 then passes through a vacuum chamber 113 (connected to a vacuum pump not shown), arranged between an inlet pipe 113a and an outlet pipe 113b which opens into an impregnation chamber 114, the two pipes preferably of rigid wall having for example a minimum section greater (typically twice as long) than the total fiber section and a length much greater (typically 50 times more) than said minimum section.

[00128] As already taught by the aforementioned application EP-A-1 174 250, the use of pipes with a rigid wall, both for the inlet hole in the vacuum chamber and for the outlet orifice of the vacuum chamber and the transfer from from the vacuum chamber to the impregnation chamber, it proves to be compatible at the same time with high rates of passage of the fibers through the holes without breaking the fibers, but also allows to ensure a sufficient tightness. It is enough, if experimentally necessary, to look for the largest passage section, considering the total section of the fibers to be treated, still allowing to offer a sufficient watertightness, considering the speed of advance of the fibers and the length of the pipes. Typically, the vacuum inside the chamber 113 is for example on the order of 0.1 bar, the length of the vacuum chamber is about 1 meter.

[00129] At the outlet of the vacuum chamber 113 and the outlet pipe 113b, the arrangement 112 of fibers 111 passes through an impregnation chamber 114 comprising a supply reservoir 115 (connected to a metering pump not shown) and an impregnation reservoir 116 fully filled with impregnation composition 117 based on a hardenable vinylester resin (eg “E-Nova FW 2045” by DSM). By way of example, composition 117 further comprises (at a weight ratio of 1 to 2%) a photoinitiating agent suitable for UV and/or UV-visible radiation with which the composition will be further treated, for example bis-(2,4,6-trimethylbenzoyl)-phenylphosphine ("Irgacure 819" from BASF). It may also comprise (for example about 5% to 15%) a crosslinking agent such as for example tris(2-hydroxyethyl)isocyanurate triacrylate ("SR 368" from the company Sartomer). Of course, the impregnation composition 117 is in a liquid state.

[00130] Preferably, the length of the impregnation chamber is several meters, for example between 2 and 10 m, in particular between 3 and 5 m.

[00131] Thus, from the impregnation chamber 114, in a watertight outlet pipe 118 (still under primary vacuum), an impregnate that comprises for example (% by weight) from 65 to 75% of solid fibers 111, the rest ( 25 to 35%) consisting of the liquid impregnation matrix 117.

[00132] The impregnate then passes through the calibrating means 119 which comprise at least one calibrating die 120 of which the channel (not shown here), for example circular, rectangular or even conical, is adapted to the special conditions of Realization. By way of example, this channel has a minimal circular cross-section whose downstream orifice has a diameter slightly larger than that of the targeted monofilament. Said 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 great dimensional accuracy to the finished product, it can also play a role in dosing the ratio of fiber to resin. According to a possible variant of embodiment, the die 120 can be directly integrated into the impregnation chamber 114, which, for example, avoids the use of the outlet pipe 118.

[00133] Preferably, the length of the sizing zone is several centimeters, for example between 5 and 50 cm, in particular between 5 and 20 cm.

[00134] Thanks to the calibration means (119, 120) a “liquid” composite monofilament (121) is obtained at this stage, liquid in the sense that its impregnation resin is at this stage still liquid, of which the shape of the cross section is preferably essentially circular.

[00135] At the outlet of the calibration means (119, 120), the liquid composite monofilament (121) thus obtained is then polymerized by passing it through a UV radiation chamber (122) comprising a tube made of watertight glass (123) through which the composite monofilament runs; said tube, of which the diameter is typically a few cm (for example 2 to 3 cm), is irradiated by a plurality (here, for example in number of 4) of UV radiators (124) in line ("UVAprint" lamps) from the company Dr. Honle, of wavelength 200 to 600 nm) arranged at a short distance (a few cm) from the tube made of glass. Preferably, the length of the radiation chamber is several meters, for example between 2 and 15 m, in particular between 3 and 10 m. The radiation tube 123 is in this example carried by a stream of nitrogen.

[00136] The radiation conditions are preferably adjusted in such a way that, at the exit of the impregnation chamber, the temperature of the monofilament made of CVR, measured on the surface of the latter (for example with the aid of a thermocouple), is higher than Tg (Tg1) of the crosslinked resin (in other terms greater than 150°C, and more preferably less than 270°C.

[00137] Once the resin has been polymerized (hardened), the monofilament made of CVR (125), this time in solid state, dragged in the direction of arrow F, then arrives at the final receiving coil (126).

[00138] Finally, a finished composite block of manufacture is obtained as outlined in figure 1, in the form of a monofilament made of continuous CVR (10), of very large length, from which the unitary glass filaments (101) are distributed homogeneously throughout the volume of hardened resin (102). Its diameter is for example equal to about 1 mm. The process described above can be carried out at high speed, preferably above 50 m/min., for example between 50 and 150 m/min.

[00139] Advantageously, before placing the thermoplastic material sheath (12), the monofilament made of CVR thus obtained can be subjected to an adhesion treatment in order to improve the subsequent adhesion between the previously described thermoset resin (102) and the thermoplastic sheath (12). An appropriate chemical treatment could, for example, consist of a previous passage in an aqueous bath based on epoxy resin and/or isocyanate compound, followed by at least one thermal treatment that aims to eliminate the water and polymerize the adhesive layer.

[00140] Such adhesion treatments are well known to the practitioner. For example, a sizing operation will be carried out by passing through an aqueous bath (about 94% water) essentially based on epoxy resin (polyglycerol polyglycidyl ether "DENACOL" EX-512 from Nagase ChemteX Corporation, approx. 1 %) and isocyanate compound (caprolactam blocked, “GRILBOND” IL-6 from EMS, approx. 5 %), sizing step followed by drying (30 s at 185°C) and then heat treatment (30 s at 200 °C).

[00141] Once the monofilament (10) made of CVR is thus finished and glued, the latter is coated, covered in a known way with a layer of thermoplastic material (12), for example by passing the monofilament, and even if it is the case of several monofilaments, arranged in parallel, through an appropriate extrusion head that delivers the thermoplastic material in the molten state.

[00142] The step of coating or coating by the thermoplastic material (12) is carried out in a manner known to the professional. It consists, for example, of simply making the or each monofilament made of CVR pass through one or more dies of an adapted diameter, in extrusion heads heated to appropriate temperatures, or even in a coating bath that contains the thermoplastic material previously placed in solution. within an appropriate organic solvent (or mixture of solvents).

[00143] By way of example, the coating of a monofilament made of CVR with a diameter close to 1 mm by a layer of PET with a minimum thickness Em equal to 0.2 mm, to obtain a multicomposite reinforcement that has a total diameter of about 1.4 mm, is carried out in an extrusion-coating line that comprises two dies, a first die (counter or upstream die) with a diameter equal to about 1.05 mm and a second die (or downstream) of diameter equal to about 1.45 mm, both arranged in an extrusion head brought to about 290°C.

[00144] The PET (“Artenius Design +” from the Artenius company; Tg2 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 made of CVR, through the coating head, at a wire travel speed typically equal to several tens of m/min., for an extrusion pump flow rate typically of several tens of cm3/min. At the exit of this first coating, the yarn can be immersed inside a cooling tank filled with cold water, to solidify and condense the polyester in its amorphous state, and then dried, for example in line by an air nozzle, or by passing the receiving coil in the greenhouse.

[00145] At the exit of the extrusion head, the filament(s) thus coated 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 water bath followed by a drying step.

[00146] The multicomposite reinforcement of the invention thus obtained, as schematized for example in figure 2b, has the following final properties:

[00147] MD equal to about 1.0 mm; In equal to about 0.2 mm; DR equal to about 1.4 mm; Tgi equals about 205°C, Tg2 equals about 76°C. A(M) equals about 4.5%.; (M) equal to about 43 GPa; E(R) equal to about 14 GPa; E'190(M) equal to about 37 GPa; E'(Tg1-25) / E'20(M) equal to about 0.92; elastic deformation in compression under bending of the monofilament equal to about 3.6%; flexural compression rupture stress of the monofilament equal to about 1350 MPa; weight ratio of glass fibers in the monofilament equal to about 70%; initial modulus in extension of the thermoset vinylester resin, at 20°C, equal to about 3.6 GPa; initial modulus in extension of PET (at 20°C) equal to about 1100 MPa.

[00148] 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 reinforcing belts, pneumatic or non-pneumatic, of all types of vehicles, in particular vehicles of tourism or industrial vehicles such as Heavy Vehicles, Civil Engineering, Airplanes, other transport or maintenance vehicles.

[00149] By way of example, figure 9 represents in a very schematic way (without respecting a specific scale), a radial section of a pneumatic belt, according to the invention not in this general representation.

[00150] This pneumatic belt 200 comprises a top 202 reinforced by butt armor or strip 206, two flanks 203 and two lugs 204, each of these lugs 204 being reinforced with a cord 205. The top 202 is topped by a band of tread not shown in this schematic figure. A carcass armature 207 is wound around the two cords 205 on each bead 204, the turning 208 of this armature 207 being, for example, arranged towards the outside of the tire 200 which is shown here mounted on its rim 209. Of course, this pneumatic belt 200 also comprises, in a known manner, a layer of gum 201 commonly called a gum or sealing layer, which defines the radially inner face of the belt and which is intended to protect the carcass ply from the diffusion of air coming from the space inside the belt. pneumatic belt.

[00151] The carcass reinforcement 207, in the belts of the prior art, is generally constituted by at least one rubber canvas reinforced by textile or metallic reinforcements called "radial", that is to say that these reinforcements are arranged practically parallel to each other and extend from one bead to the other so as to form an angle between 80° and 90] with the median circumferential plane (a plane perpendicular to the tire's axis of rotation which is situated halfway between the two beads 204 and passes through the middle of the top.

[00152] The band 206 is, for example, constituted in the belts of the prior art, by at least two rubber plies called "working plies" or "triangulation plies", superimposed and crossed, reinforced by metallic cables arranged substantially parallel to each other. to the others and inclined in relation to the median circumferential plane, these work plies may or may not be associated with other plies and/or rubber fabrics. The main function of these working plies is to give the pneumatic belt high drift stiffness. The band 206 can also comprise in this example a rubber tarpaulin called "lining canvas" reinforced by reinforcement threads called "circumferential", that is to say that these reinforcement threads are arranged practically parallel to each other and extend substantially circumferentially in around the pneumatic belt so as to form an angle preferably comprised in a range of 0 to 10° with the median circumferential plane. These circumferential reinforcing threads have the main function of resisting the top spinning at high speed.

[00153] A pneumatic belt 200, when it is according to the invention, has as a preferred characteristic that at least its belt (206) and/or its carcass armor 92070 comprises a multilayer laminate according to the invention, consisting of at least at least one multicomposite reinforcement according to the invention disposed between and in contact with two layers of dienic rubber composition. According to a special embodiment of the invention, this multi-composite reinforcement of the invention can be used in the form of parallel segments arranged under the tread, as described in the cited patent EP 1 167 080. According to another possible embodiment of the invention, it is the bead zone that can be reinforced by such a multi-composite reinforcement; are, for example, the cords (5) which could be made up, in whole or in part, of a multicomposite reinforcement according to the invention.

[00154] In these examples of figure 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. , a vulcanization system and the usual additives. Thanks to the invention, compared to steel cable reinforced rubber compositions, they can advantageously be devoid of a metal salt such as a cobalt salt. The adhesion between the multi-composite reinforcement of the invention and the rubber layer that covers it can be ensured in a simple and known way, for example with a usual glue of the RFL type (resorcinol-formaldehyde-latex), or with the aid of more recent glues. such as described for example in the cited applications WO 2013/017421 , WO 2013/017422 , WO 2013/017423 .

[00155] Special tests on pneumatic belts were carried out, in which multi-composite reinforcements d according to the invention as previously manufactured were used as elongated reinforcements, that is to say non-twisted, in crossed working plies in place of cables made of conventional steel, as described in the aforementioned document EP 1 167 080.

[00156] These tests clearly demonstrated that the multi-composite reinforcements of the invention, thanks to their improved compression properties, did not suffer compression breaks during the actual manufacture of these pneumatic belts, contrary to prior art CVR monofilaments such as described in EP 1 167 080.

[00157] While making pneumatic belts lighter and eliminating the risks related to corrosion, in relation to belts of which the belt is conventionally reinforced with steel cables, the multicomposite reinforcements of the invention also revealed as another notable advantage that of not increasing the rolling noise of pneumatic beads, contrary to other known textile solutions (reinforcements).

[00158] These multi-composite reinforcements of the invention have also shown excellent performance as circumferential reinforcements in non-pneumatic type belts such as described in the introduction to this report.

[00159] In conclusion, the advantages of the multilayer laminate and the multicomposite reinforcement of the invention are numerous (small thickness, small density, low cost, insensitivity to corrosion) compared to conventional metallic fabrics, and the results obtained thanks to the invention (in particular in improved compression) open up a very large number of possible applications for it, notably as a reinforcing element for the pneumatic belts band, arranged between the tread and the carcass armor of such belts. Table

Claims (27)

1. Multicomposite reinforcement (R1, R2) comprising one or more monofilament(s) (10) made of glass-resin composite (in abbreviated “CVR”) comprising glass filaments (101) embedded within a thermoset resin (102 ) whose glass transition temperature is recorded Tgi, characterized by the fact that: - a layer of thermoplastic material (12) covers said monofilament or, if there are several, each monofilament individually or collectively all or at least part of the monofilaments; - said monofilament or, if there are several, all or at least a part of the monofilaments 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 extension module, annotated E(M), measured at 20°C, greater than 35 GPa. 2. Multicomposite reinforcement according to claim 1, characterized in that Tgi is greater than 195°C, preferably greater than 200°C. 3. Multicomposite reinforcement according to claims 1 and 2, characterized in that the annotated glass transition temperature Tg2 of the thermoplastic material is greater than -30°C, preferably greater than 20°C. 4. Multicomposite reinforcement according to claim 3, characterized in that Tg2 is greater than 50°C, preferably greater than 70°C. 5. Multicomposite reinforcement according to any one of claims 1 to 4, characterized in that A(M) is greater than 4.2%, preferably greater than 4.4%. 6. Multicomposite reinforcement according to any one of claims 1 to 5, characterized in that E(M) is greater than 40 GPa, preferably greater than 42 GPa. 7. Multicomposite reinforcement according to any one of claims 1 to 6, characterized in that said monofilament or, if there are several, all or at least a part of the monofilaments presents a real part of the complex module annotated E'I90 (M>, measured at 190°C by the DTMA method, which is greater than 30 GPa. 8. Multi-composite reinforcement according to any one of claims 1 to 7, characterized in that said monofilament or, if there are several, the entirety or at least a part between them presents an elastic deformation in compression under bending that is superior to 3.0%, preferably greater than 3.5%. 9. Multicomposite reinforcement according to any one of claims 1 to 8, characterized in that said monofilament or, if there are several, the entirety or at least a part between them presents a breaking stress in compression under bending that is greater than 1000 MPa, preferably greater than 1200 MPa. 10. Multicomposite reinforcement according to any one of claims 1 to 9, characterized in that the thermoset resin (102) of said monofilament or, if there are several, of all or at least a part of the monofilaments is a polyester resin or vinylester, preferably vinylester. 11. Multicomposite reinforcement according to any one of claims 1 to 10, characterized in that the thermoset resin (102) of said monofilament or, if there are several, of all or at least part of the monofilaments, has a modulus initial in extension, measured at 20°C, which is greater than 3.0 GPa, preferably greater than 3.5 GPa. 12. Multicomposite reinforcement according to any one of claims 1 to 11, characterized in that the noted diameter DM of said monofilament or of each monofilament if there are several is comprised between 0.2 and 2.0 mm, preferably between 0 .3 and 1.5 mm. 13. Multicomposite reinforcement according to any one of claims 1 to 12, characterized in that the minimum thickness noted Em of the layer of thermoplastic material that covers said monofilament or each monofilament if there are several, is between 0.05 and 0.5 mm, preferably between 0.1 and 0.4 mm. 14. Multicomposite reinforcement according to any one of claims 1 to 13, characterized in that the thermoplastic material is a polymer or a polymer composition. 15. Multicomposite reinforcement according to claim 14, characterized in that the polymer is chosen 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. Multicomposite reinforcement according to any one of claims 1 to 15, characterized in that the initial modulus in extension of the thermoplastic material, measured at 20°C, is between 300 and 3,000 MPa, preferably between 500 and 2 500 MPa. 17. Multicomposite reinforcement according to claim 16, characterized in that the initial modulus in extension of the thermoplastic material, measured at 20°C, is between 500 and 1,500 MPa. 18. Multicomposite reinforcement according to any one of claims 1 to 17, characterized in that the elastic elongation of the thermoplastic material, measured at 20°C, is greater than 5%, preferably greater than 8%. 19. Multicomposite reinforcement according to any one of claims 1 to 18, characterized in that the elastic elongation of the thermoplastic material, measured at 20°C, is greater than 10%, preferably greater than 15%. 20. Multicomposite reinforcement according to any one of claims 1 to 19, characterized in that the elongation at break annotated A(R), measured at 20°C, is greater than 3.0%, preferably equal to or greater than 3.5%. 21. Multicomposite reinforcement according to any one of claims 1 to 20, characterized in that the initial modulus in extension annotated E(R), measured at 20°C, is greater than 9 GPa, preferably greater than 12 GPa. 22. Multi-layer laminate characterized in that it comprises at least one multi-composite reinforcement as defined in any one of claims 1 to 21, disposed between and in contact with two layers of rubber composition. 23. Finished article or semi-finished product made of plastic material or made of rubber characterized in that it comprises a multi-composite reinforcement as defined in any one of claims 1 to 21 or a multi-layer laminate as defined in claim 22. 24. Strap, pneumatic or non-pneumatic, characterized in that it comprises a multi-composite reinforcement as defined in any one of claims 1 to 21, or a multi-layer laminate as defined in claim 22. 25. Strap according to claim 24, characterized by the fact that the multi-composite reinforcement or the multi-layer laminate is present in the strap band or in the strap's carcass armor. 26. Strap according to claim 24, characterized in that the multi-composite reinforcement or the multi-layer laminate is present in the bead zone of the strap. Use of a reinforcement as defined in any one of claims 1 to 21, or of a multilayer laminate as defined in claim 22, characterized in that it is used as a reinforcing element in an article or semi-finished product made of plastics or made of rubber.

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