Metal reinforcement element covered with an adhesive composition

Abstract

The invention relates to a metallic reinforcement element covered with a layer of adhesive composition, which layer covers at least a part of the reinforcement element, characterized in that the adhesive composition comprises at least: - a compound having at least two epoxy functions; - a phenol having one or more aromatic ring(s), it being understood that: in the case of a single aromatic ring, the latter carries at least three hydroxyl functions; or in the case of several aromatic rings, at least two of them each carry at least three hydroxyl functions, it being understood that at least one ortho position of at least one of these hydroxyl functions is unsubstituted; and - a compound comprising at least one double bond which may have a linear, branched and / or cross-linked macrostructure which may organize itself into a structure of the type "core shell rubber" or micelle or particle.

Description

Title of the invention: Metallic reinforcement element coated with an adhesive composition

[0001] The field of the present invention is that of metallic reinforcing elements and adhesive compositions or "glues" intended to make such metallic reinforcing elements adhere to rubber matrices such as those commonly used in semi-finished rubber articles or products.

[0002] The present invention relates more particularly to metallic reinforcement elements covered by at least one adhesive layer based on a compound comprising at least two epoxy functions, a phenol comprising one or more aromatic ring(s), and a compound comprising at least one double bond which may have a linear, branched and / or cross-linked macrostructure which may organize itself into a "core shell rubber" type structure or micelle or particle.

[0003] Prior art is known of steel reinforcement elements coated with aqueous adhesive layers based on a phenol-aldehyde resin and an unsaturated elastomer latex, in particular coated steel reinforcement elements capable of reinforcing tire structures, in particular of application EP 3102407.

[0004] Prior art is also known from document EP 3688110 of metallic reinforcement elements covered with an adhesive composition based on at least one phosphate salt and a resin based on a compound comprising at least one aldehyde function and a phenol and in particular coated steel reinforcement elements capable of reinforcing tire structures.

[0005] The problem with aqueous metal-rubber adhesive compositions is that they are most often sensitive to water and it is interesting to improve their protective action against thermal aging mechanisms under a humid atmosphere.

[0006] However, during their research, the Applicant discovered an adhesive composition that meets the above objective while maintaining an acceptable level of adhesion.

[0007] The invention aims to find a metallic reinforcement element covered with a layer of adhesive composition to remedy these drawbacks.

[0008] To this end, the invention relates to a metallic reinforcement element covered with a layer of adhesive composition, which layer covers at least a part of the reinforcement element, characterized in that the adhesive composition comprises at least: - a compound comprising at least two epoxy functions; - a phenol comprising one or more aromatic ring(s), it being understood that: in the case of a single aromatic ring, the latter must bear at least three hydroxyl groups; or in the case of several aromatic rings, at least two of them each carry at least three hydroxyl functions, it being understood that at least one ortho position of at least one of these hydroxyl functions is unsubstituted; and - a compound comprising at least one double bond which may have a linear, branched and / or cross-linked macrostructure which may organize itself into a "core shell rubber" type structure or micelle or particle.

[0009] This multi-component formulation offers an excellent compromise in terms of the mechanical strength of the assembly after manufacturing and over time. The epoxy resin formed from the hardener and the compound comprising at least two epoxy functional groups ensures good adhesion to the metal and also protects it from thermal aging, particularly in humid environments.

[0010] By "core shell rubber" is meant a block elastomer organizing itself in a core-crown structure.

[0011] By phenol, we mean a phenolic hardener.

[0012] Preferably, the metallic reinforcement element is wire.

[0013] By wire reinforcement element, we mean long, elongated elements of great length relative to their cross-section, regardless of the shape of the latter, for example, circular, oblong, rectangular, square, or even flat. This wire element may be straight or non-straight, for example, twisted or corrugated. When circular in shape, the diameter of each wire reinforcement element is preferably less than 5 mm, more preferably within a range of 0.1 to 0.5 mm. Also included are strips or bands that have a great length relative to their thickness.

[0014] The expression "composition based on" should of course be understood as a composition comprising the mixture and / or reaction products of the various basic constituents used for this composition, some of which may be intended to react or are likely to react with each other or with their immediate chemical environment, at least in part, during the various manufacturing phases of the composition, the reinforcing element, the composites or the finished articles, in particular during a baking step.

[0015] Any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than a to less than b (i.e. excluding bounds a and b) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from a to b (i.e. including the strict bounds a and b).

[0016] Within the scope of the invention, the carbon products mentioned in the description may be of fossil origin or bio-based. In the latter case, they may be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass.

[0017] Within the scope of the invention, it may also be envisaged that the carbon products mentioned in the description include isotopes of certain chemical elements.

[0018] Preferably, the covered metal reinforcement element comprises one or more wire reinforcement elements, each comprising a steel core. The steel core is monolithic, that is to say, it is, for example, formed from raw material or by casting.

[0019] Steel may have a pearlitic, ferritic, austenitic, bainitic, martensitic microstructure or a microstructure resulting from a mixture of these microstructures.

[0020] Preferably, the steel comprises a carbon content of 0.2% to 1% by mass, and more preferably 0.5% to 0.95% by mass. Preferably, the steel comprises a manganese content of 0.3% to 0.8% by mass, a silicon content of 0.1% to 0.6% by mass, a phosphorus content of up to 0.05% included terminal by mass, a sulfur content of up to 0.05% included terminal by mass, and a nitrogen content of up to 0.008% included terminal by mass. Optionally, the steel comprises up to 0.1% included terminal, preferably 0.05% included terminal, and more preferably 0.02% included terminal by mass of vanadium and / or molybdenum.

[0021] In one embodiment, the steel used comprises less than 0.5%, preferably at most 0.05% inclusive of terminal, and more preferably at most 0.02% inclusive of terminal, by mass of chromium.

[0022] In another embodiment using so-called stainless steel, the steel comprises at least 0.5% inclusive terminal, preferably at least 5% inclusive terminal and more preferably at least 15% inclusive terminal by mass of chromium.

[0023] Preferably, the steel comprises at least 2% inclusive terminal, preferably at least 4% inclusive terminal and more preferably at least 10% by mass of nickel.

[0024] Advantageously, the steel core is devoid of a metallic coating layer.

[0025] Preferably, the steel core of each of the one or more wire reinforcement elements is devoid of a metallic coating layer.

[0026] By "without a metallic layer," it is meant that the steel is not coated with a metal other than itself. In particular, the reinforcing element is without a layer of zinc, copper, tin, or an alloy of these metals, for example, such as brass and bronze.

[0027] Thus, in the embodiment in which the coated steel reinforcement element comprises a single wire reinforcement element, the adhesive layer may cover certain parts of this element or its entirety. In the embodiment in which the coated steel reinforcement element comprises several wire reinforcement elements, the adhesive layer may cover several wire elements without covering others, or it may cover only certain parts of some or all of the wire elements.

[0028] Advantageously, the adhesive composition directly covers a layer of a metallic coating directly covering at least a part of the steel core of the wire reinforcement element or each element.

[0029] Preferably, the metal of the metallic coating layer directly covering at least a portion of the steel core of the wire reinforcement element(s) is selected from zinc, copper, tin, and alloys of these metals. Brass is an example of an alloy of these metals.

[0030] Advantageously, the adhesive composition comprises less than 5% by weight of water, preferably less than 1% by weight of water and more preferably is free of water.

[0031] Advantageously, the adhesive composition comprises less than 5% by weight of organic solvent, preferably less than 1% by weight of organic solvent and more preferably is free of organic solvent.

[0032] This "epoxy-hardener-double-bonded compound" adhesive composition is formulated without solvents, while remaining liquid to facilitate its application to the reinforcement. This significantly reduces the environmental impact and industrial production cost of the adhesive composition. No energy is required to evaporate and process the organic solvent. There are no VOC (volatile organic compound) emissions during the coating or heat treatment of the adhesive composition.

[0033] By definition, an organic solvent is understood to be a compound that must be removed at least once during the manufacturing of the adhesive composition. Thus, the organic solvent dissolves the reactants and brings them into contact. The organic solvent does not react chemically with the dissolved compounds; it is inert.

[0034] In one embodiment, the layer of adhesive composition directly covers the reinforcing element.

[0035] By layer covering "directly" an object, it is understood that the layer is in contact with the object without any other object, in particular another layer or another coating, being interposed between the two.

[0036] In another preferred embodiment, the adhesive layer covers wire-drawing residues present on the surface of the reinforcing element. These residues on the surface of the reinforcements are heterogeneous in composition and quantity. Thus, in this embodiment, the adhesive layer may not completely cover the reinforcing element.

[0037] The adhesive composition therefore comprises at least one (i.e. one or more) "epoxy-hardener-compound comprising a double bond" resin based on at least one (i.e. one or more) compound comprising at least one epoxy function, at least one (i.e. one or more) phenol comprising one or more aromatic ring(s) and at least one (i.e. one or more) compound comprising at least one double bond having a "core shell rubber" or micelle or particle type structure, constituents which will be described in detail below.

[0038] 1.1 - Compound comprising at least two epoxy functions

[0039] The first constituent of the adhesive composition is a compound comprising at least two epoxy functions.

[0040] Preferably, the compound comprising at least two epoxy functions is chosen from 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, bis (3,4-epoxycyclohexylmethyl) adipate and diglycidyl 1,2-cyclohexanedicarboxylate.

[0041] Preferably, the adhesive composition comprises at least two compounds having at least two epoxy functions, preferably the second compound is chosen from diglycidyl ether, poly (propylene glycol) diglycidyl ether and 1,4-butanediol diglycidyl ether.

[0042] 1,2 - Phenol comprising one or more aromatic ring(s)

[0043] The second constituent of the adhesive composition is a phenol comprising one or more aromatic ring(s).

[0044] In the case of a phenol comprising a single aromatic ring, the latter carries at least three hydroxyl functions.

[0045] Preferably, the phenol is chosen from the group consisting of phloroglucinol, hydroxycatechol, pyrogallol, gallic acid, tannic acid and mixtures of these compounds.

[0046] 1.3 - Compound comprising at least one double bond which may have a structure linear, branched or a "core shell rubber" type structure or micelle or particle

[0047] The third constituent of the adhesive composition is a compound comprising at least one double bond which may have a linear, branched and / or cross-linked macro structure which may organize itself into a "core shell rubber" type structure or micelle or particle.

[0048] Preferably, the compound comprising at least one double bond which may have a linear, branched and / or cross-linked macrostructure which may organize itself into a "core shell rubber" type structure or micelle or particle is chosen from dicarboxy-terminated poly(acrylonitrile-co-butadiene), polybutadienes, polyisoprene, famesene-butadiene copolymers and a polybutadiene core shell rubber which may already be dispersed in the compound comprising at least two epoxy functions and mixtures of these compounds.

[0049] Preferably, the "core shell rubber" are block elastomers, containing polybutadiene blocks which are in the form of core-crown particles ("shell" in English) and are pre-dispersed in the compound having at least two epoxy functions such as, for example, Kaneka's MX553 compound.

[0050] 1.4 - Manufacture of the adhesive composition

[0051] The constituents of the adhesive composition are mixed at a suitable temperature chosen by a person skilled in the art in relation to the physical properties of the raw materials, for example 100°C, until a homogeneous mixture is obtained.

[0052] The mixture is used directly or can be stored before use and can be heated to adapt the viscosity according to the coating method chosen on the metal reinforcement element.

[0053] Preferably, in the final adhesive composition thus prepared, the hardener content, i.e. phenol comprising one or more aromatic rings, ranges from 5 to 50% by weight and preferably from 10 to 30% by weight.

[0054] Method for manufacturing the coated reinforcement element

[0055] Another object of the invention relates to a method of coating the reinforcing element in the composite in which a first heat treatment step is carried out on the adhesive composition on the reinforcing element, by heating to a temperature ranging from 50 to 300°C and in a second step, the coated metallic reinforcing element is heated in the rubber matrix to form the composite at a temperature above 100°C.

[0056] During the process described above, at least part of the metal reinforcement element is covered by the adhesive layer comprising the adhesive composition described above.

[0057] This coating step can be carried out by any suitable method, in particular by any known coating technique such as, for example, spraying, free coating, pultrusion or other equivalent thin or ultra-thin film deposition technique, or by a combination of one or more of these techniques.

[0058] The thickness of the layer made up of the adhesive composition coating each wire reinforcement element is within a range of values ​​from 0.1 to 100 pm, preferably from 1 to 100 pm and more preferably from 1 to 40 pm.

[0059] Prior to the step of coating the metallic reinforcement element with the adhesive layer comprising the adhesive composition, each wire reinforcement element may undergo treatment steps, for example descaling, cleaning, or even heat treatment or plasma activation. Examples of these treatment steps are described in particular in documents US20100170624, US5535612, and JP2000219938.

[0060] Composite

[0061] Another object of the invention relates to a rubber composite reinforced with at least one coated metal reinforcement element as described above comprising a rubber matrix in which the coated metal reinforcement element is embedded.

[0062] Such composites include pipes, seals, belts, conveyor belts, tracks, and vehicle tires, both in their raw state (i.e., before cross-linking or vulcanization) and in their cured state (after cross-linking or vulcanization). In preferred configurations, such composites take the form of a sheet or strips.

[0063] First, the adhesive composition is coated onto the metal reinforcement from a gluing line at a predetermined temperature range, this temperature being lower than the initial curing temperature of the composition, while being adapted to the chosen process. Then, curing is carried out at a temperature range from 100 to 250°C chosen by those skilled in the art.

[0064] Obtaining the composite requires a further step in which the metallic reinforcing element is trapped in the elastomeric composition to achieve adhesion with the elastomeric matrix during the curing of the composite.

[0065] A particularly preferred method for coating the adhesive composition is that described in application FR2213647.

[0066] A person skilled in the art will be able to adjust, where necessary, the temperature and duration of the above heat treatment, according to the specific conditions of implementation of the invention, in particular the exact nature of the adhesive composition or the type of steel. In particular, a person skilled in the art will benefit from performing temperature and treatment duration sweeps in order to determine, through successive approximations, the operating conditions leading to the best adhesion results for each specific embodiment of the invention.

[0067] The invention therefore applies to any type of rubber composite that can be obtained by the process described above, comprising at least one matrix of rubber, in particular diene elastomer, bonded to the metal reinforcement element via an adhesive interface based on the adhesive composition described above.

[0068] The diene elastomer of the rubber matrix is ​​preferably chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR), butadiene-styrene-isoprene copolymers (SBIR) and mixtures of these elastomers. We can also mention the copolymer of ethylene and a 1,3-diene obtained, a copolymer of ethylene and 1,3-butadiene, and an ethylene-butadiene elastomer, designated under the term "EBR". A preferred embodiment consists of 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), synthetic polyisoprenes (IR), the various isoprene copolymers and mixtures of these elastomers.Among butadiene copolymers, butadiene-styrene (SBR), isoprene-butadiene (BIR), and isoprene-butadiene-styrene (SBIR) copolymers are particularly noteworthy. This butadiene elastomer is preferably a cis-1,4 polybutadiene. The isoprene elastomer is preferably natural rubber or a synthetic cis-1,4 polyisoprene.

[0069] PNEUMATIC

[0070] Another object of the invention relates to a tire comprising at least one covered metal reinforcement element or a rubber composite as described above.

[0071] The covered reinforcement elements are advantageously usable for the reinforcement of tires of all types of vehicles, in particular passenger vehicles or industrial vehicles such as heavy goods vehicles.

[0072] By way of example, the attached [Fig.1] represents in a very schematic way (without respecting a specific scale), a radial section of a tire according to the invention for a heavy goods vehicle.

[0073] This tire 1 comprises a crown 2 reinforced by a crown reinforcement or belt 6, two sidewalls 3, and two bead 4, each of these bead 4 being reinforced with a bead 5. The crown 2 is surmounted by a tread not shown in this schematic figure. A carcass reinforcement 7 is wound around the two bead 5 in each bead 4, the folded end 8 of this reinforcement 7 being, for example, oriented towards the outside of the tire 1, which is shown here mounted on its rim 9. The carcass reinforcement 7 is, in a manner known per se, made up of at least one layer reinforced by so-called "radial" cables, for example, metallic ones, that is to say, these cables 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 (plane perpendicular to the axis of rotation of the tire which is located halfway between the two ridges 4 and passes through the middle of the apex reinforcement 6).

[0074] This tire 1 of the invention has, for example, the characteristic that at least one apex reinforcement 6 and / or its carcass reinforcement 7 comprises a coated metallic reinforcement element or a composite according to the invention.

[0075] Of course, the invention relates to the objects previously described, namely the coated metal reinforcement element and the rubber composite as pneumatic comprising it, both in the raw state (before baking or vulcanization) and in the baked state (after baking).

[0076] EXAMPLES OF IMPLEMENTATION OF THE INVENTION AND COMPARATIVE TESTS

[0077] These tests demonstrate that: - adhesion to a rubber matrix of metallic reinforcement elements covered by an adhesive composition according to the invention is acceptable; - The adhesive composition allows for long-lasting adhesion of the reinforcement elements over time and enables resistance to thermal aging in humid atmospheres.

[0078] To this end, several adhesive compositions, hereinafter referred to as Cl to C-3 and Tl to T3, were prepared as described above. Their formulations (expressed as mass percentages) are presented in the attached Table 1.

[0079] Each adhesive composition Cl to C-3 is based on an adhesive composition according to the invention.

[0080] The composition Tl covered by application EP3688110 is an aqueous composition based on phloroglucinol, terephthalaldehyde, sodium phosphate, elastomer latex and ammonia.

[0081] Compositions T2 and T3 are control compositions outside the scope of the invention.

[0082] Here, metallic reinforcing elements forming an assembly of the type have been tested. 1+6+12 with the center wire having a diameter of 0.20 mm and the other wires of 0.18 mm (19.18 cables) commonly used for making carcass plies of heavy-duty tires: - For 19.18 uncoated steel, the unit wires of the metal reinforcement elements are uncoated steel wires; - For the 19.18 brass-plated steel, the individual wires of the metal reinforcement elements are steel wires coated with a layer of brass. The brass thickness ranges from 50 nm to 300 nm.

[0083] The rubber composition of the rubber matrix is ​​a conventional composition usable for calendering metallic tire plies, based on natural rubber, carbon black and usual additives. In this case, the rubber composition includes 100 parts natural rubber, 47 parts 300 series carbon black, 1.5 parts Nl, 3-dimethylbutyl-N-phenyl-para-phenylenediamine, 1.1 parts a cobalt salt, 0.9 parts stearic acid, 4.5 parts insoluble molecular sulfur, 0.8 parts N,N-dicyclohexyl-2-benzothiazolesulfamide, 0.15 parts a retarder and 7.5 parts ZnO.

[0084] The reinforcements are coated with the adhesive compositions and then undergo a heat treatment for cross-linking for 2 minutes at 220°C (for example). The coated reinforcements and the rubber compositions are used to make a reinforced product in the form of a test specimen according to the following protocol: A rubber block is made from two plates, applied one on top of the other before curing. The two plates of the block consist of the same rubber composition. During the block's preparation, the metallic reinforcement elements are sandwiched between the two plates in their raw state, at equal distances, leaving one end of the reinforcement element protruding on either side of the plates, long enough for subsequent tensile strength. The block containing the reinforcements is then cured.As an example, in this case, the block is cooked at 140°C for a time varying from 5 minutes to 50 minutes depending on the composition under pressure of 6 tonnes.

[0085] After curing, the composite specimen, consisting of the cross-linked block and coated metal reinforcement elements, is placed in the jaws of a suitable tensile testing machine to allow each section to be tested individually at a given speed and temperature (for example, in this case, 100 mm / min and ambient temperature). The adhesion levels are characterized by measuring the pull-out force required to detach the sections from the specimen. The initial pull-out test at 20°C is shown in Table 1 below. A pull-out force result marked (+) indicates that the initial pull-out level is below the control value T1, and a pull-out force result marked (++) indicates that the initial adhesion is acceptable.

[0086] [Tables 1] Adhesive compositions Cl C-l' C-2 C-3 Tl T-2 T-3 Phloroglucinol (1) 14 12 - - 1.33 16.5 - Resorcinol (2) - - - - - - 17 Tannic acid (3) - - 26 - - - - Gallic acid (4) - - - 22 - - - Neopentylglycol diglycidyl ether (5) 36 - 24 28 - 41.2 33 MX-553 (6) 50 50 50 50 - - 50 3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate (7) - 38 - - - 42.3 - Terephthalaldehyde (8) - - - - 0.71 - - Sodium phosphate - - - - 0.75 - - Elastomer latex - - - - 14.15 - - Ammonia - - - - 0.55 - - Water - - - - 80.5 - - Pull-out test on a reinforcing element 19.18 Adhesion 19.18 to brass-plated steel ++ ++ ++ ++ ++ + + Adhesion 19.18 to uncoated steel ++ ++ ++ ++ Not tested ++ 1. Phloroglucinol (from Chem Pacific; 99% purity); 2. Resorcinol (from the company Sigma-Aldrich); 3. Tannic acid (CAS No. 1401-55-4 from Sigma-Aldrich); 4. Gallic acid (CAS No. 149-91-7 from Sigma-Aldrich); 5. Neopentyl glycol diglycidyl ether (from the company Sigma Aldrich); 6. MX553: 3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate containing 30% by mass of "core shell rubber" (from the company Kaneka); 7. 3,4-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (from the Sigma Aldrich company); 8. 1,4 benzenedicarboxaldehyde (from the company Sigma-Aldrich).

[0087] Thus it is observed that the Cl to C-3 reinforcing elements according to the invention, whether brass-plated or not, have acceptable levels of adhesion initially.

[0088] Table 2 below represents the evolution of the pull-out force on base 100 at t=0 for all the brass-plated reinforcing elements 19.18 as described above uncoated and coated by the compositions Tl, Cl and C2 and we look at the evolution over time of the pull-out force of each reinforcing element in thermal aging under humid atmosphere, 95% relative humidity (RH) and 55°C.

[0089] These measurements are carried out at t=0 then at t= 7 and 14 days after aging at 55°C under 95% relative humidity.

[0090] [Tables2] Pull-out force (in N) Reinforcement 19.18 brass-plated steel, uncoated R0 Reinforcement 19.18 brass-plated steel, green coated with T1 Reinforcement 19.18 brass-plated steel, green coated with Cl Reinforcement 19.18 brass-plated steel, green coated with C2 T0 100% 100% 100% 100% T7 85% 45% 98% 100% T14 73% 37% 96% 100%

[0091] Compared to the uncoated brass witness R0 and the reinforcement covered by the aqueous adhesive composition Tl, the reinforcements covered with compositions Cl and C2 according to the invention do indeed show a durability of the adhesion of the reinforcement element in humid aging: 95% RH and 55°C.

[0092] Thus the reinforcement elements according to the invention make it possible to constitute effective protection against thermal aging mechanisms under a humid atmosphere.

[0093] As another advantage related to the invention, it will be noted that the adhesive composition is usable and effective on steel reinforcement elements comprising wire reinforcement elements without metallic coating and more preferably without metallic coating chosen from zinc, copper, tin and alloys of these metals, for example brass.

[0094] The invention is not limited to the embodiments described above.

[0095] It may also be possible to cover several wire reinforcement elements, each comprising a steel core. In one embodiment, the wire reinforcement elements are assembled, and then the steel cores of the wire reinforcement elements are collectively covered with the adhesive composition. In another embodiment, the steel core of each wire reinforcement element is individually covered with the adhesive composition, and then the wire reinforcement elements are assembled together.

[0096] It may also be possible to consider the use of coated steel reinforcement elements comprising an intermediate layer of non-metallic adhesion directly coated the steel core of the wire reinforcement elements, the layer of adhesive composition then directly covering this intermediate non-metallic adhesion layer.

Claims

Demands

1. A metallic reinforcing element covered with a layer of adhesive composition, which layer covers at least a part of the reinforcing element, characterized in that the adhesive composition comprises at least: - a compound having at least two epoxy functions; - a phenol having one or more aromatic ring(s), it being understood that: in the case of a single aromatic ring, the latter bears at least three hydroxyl functions; or in the case of several aromatic rings, at least two of them each bear at least three hydroxyl functions, it being understood that at least one ortho position of at least one of these hydroxyl functions is unsubstituted; and - a compound comprising at least one double bond which may have a linear, branched and / or cross-linked macrostructure which may organize itself into a structure of the type "core shell rubber" or micelle or particle.

2. A metal reinforcement element covered according to the preceding claim, comprising one or more wire reinforcement elements each comprising a steel core.

3. A coated metallic reinforcement element according to claim 2, wherein the steel core is devoid of a metallic coating layer.

4. A coated metallic reinforcement element according to claim 2, wherein the adhesive composition directly covers a layer of a metallic coating directly covering at least a portion of the steel core of the wire reinforcement element(s).

5. A coated metal reinforcement element according to the preceding claim, wherein the metal of the layer of the metal coating directly covering at least a part of the steel core of the wire reinforcement element(s) is selected from zinc, copper, tin and alloys of these metals.

6. A metal reinforcement element coated according to any one of the preceding claims, wherein the adhesive composition comprises less than 5% by weight of water, preferably less than 1% by weight of water and more preferably is free of water.

7. A coated metal reinforcement element according to any one of the preceding claims, wherein the adhesive composition comprises less than 5% by weight of organic solvent, preferably less than 1% by weight of organic solvent and more preferably is free of organic solvent.

8. A coated metal reinforcement element according to any one of the preceding claims, wherein the compound comprising at least two epoxy functions is selected from 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, bis(3,4-epoxycyclohexylmethyl) adipate and diglycidyl 1,2-cyclohexanedicarboxylate.

9. A coated metal reinforcement element according to the preceding claim, wherein the adhesive composition comprises at least two compounds having at least two epoxy functions, preferably the second compound being selected from diglycidyl ether, poly(propylene glycol) diglycidyl ether and 1,4-butanediol diglycidyl ether.

10. A coated metallic reinforcing element according to any one of the preceding claims, wherein the phenol is selected from the group consisting of phloroglucinol, hydroxycatechol, pyrogallol, gallic acid, tannic acid and mixtures of these compounds.

11. A coated metallic reinforcement element according to any one of the preceding claims, wherein the compound comprising at least one double bond which may have a linear, branched and / or cross-linked macro structure which may organize itself into a "core shell rubber" type structure or micelle or particle is selected from dicarboxy-terminated poly(acrylonitrile-co-butadiene), polybutadienes, polyisoprene, farnesene-butadiene copolymers and a polybutadiene core shell rubber which may be already dispersed in the compound comprising at least two epoxy functions and mixtures of these compounds.

12. Rubber composite reinforced with at least one metal reinforcement element covered according to any one of claims 1 to 11 comprising a rubber matrix in which the covered metal reinforcement element is embedded.

13. A method for coating the reinforcing element in the rubber composite according to the preceding claim, wherein a first heat treatment step is carried out on the adhesive composition on the reinforcing element by heating to a temperature from 50 to 300°C and in a second step, the coated metal reinforcing element is heated in the rubber matrix to form the composite at a temperature above 100°C.

14. A tire comprising at least one metallic reinforcement element covered according to any one of claims 1 to 11 or a rubber composite according to claim 12.

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