Composite comprising a metallic reinforcing element and an elastomeric composition comprising a phenol-aldehyde resin

Abstract

The invention relates to a composite comprising at least one reinforcing element having a surface comprising a copper-zinc alloy, said reinforcing element being embedded in an elastomeric composition based on at least one diene elastomer, a reinforcing filler, a sulfur-based crosslinking system comprising a metal oxide, stearic acid or one of its derivatives and a vulcanization accelerator, and a phenol-aldehyde resin based on: - at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functions in meta positions relative to each other, the two ortho positions of at least one of the hydroxyl functions being unsubstituted, and - at least one dialdehyde compound comprising two aldehyde functions, in which the phenol-aldehyde resin content ranges from 0.5 to 2 parts per million, and the mass ratio of metal oxide to stearic acid or one of its derivatives is greater than or equal to 8.

Description

Title of the invention: Composite comprising a metallic reinforcing element and an elastomeric composition comprising a phenol-aldehyde resin. Technical field of the invention

[0001] The present invention relates to the field of reinforced rubber products, in particular for pneumatic or non-pneumatic tires, as well as to articles comprising such reinforced products. Previous art

[0002] Reinforcing plies for tires or rubber-reinforced articles typically comprise a rubber compound, known as the calendered compound, and metal reinforcing cords. The calendered compound must meet numerous requirements, such as good adhesion to the metal reinforcing cords, hysteresis properties that result in a low contribution to rolling resistance, and good resistance to cracking throughout the tire's service life.

[0003] Adhesion between the wire ropes and the surrounding rubber is one of the key properties for the effectiveness of reinforcement plies in pneumatic tires or rubber-reinforced articles. Calendering compositions, which include a diene elastomer, particularly natural rubber, and a reinforcing filler, also generally include a specific vulcanization system and, as an adhesion promoter, cobalt salts. This specific vulcanization system usually includes a high sulfur content, a high zinc oxide to stearic acid mass ratio, a so-called slow vulcanization accelerator, and a vulcanization retarder. In these systems, adhesion between the calendering composition and the wire rope is created via the sulfidation of the brass-coated surface of the rope, with the cobalt salts acting to ensure the durability of the adhesion.

[0004] Numerous studies have been conducted by tire manufacturers to limit the levels of sulfur, metal oxide, and / or cobalt salts while maintaining one or more of the performance characteristics of the calendering compositions, as well as their durability. For example, documents WO2016 / 058942 and WO2016 / 0589431 propose sheathing the metal reinforcement elements, which reduces the levels of sulfur and zinc oxide in the calendering compositions of the sheathed reinforcements and decreases, or even eliminates, the cobalt content from the calendering composition. However, this approach requires sheathing the reinforcement elements.

[0005] Document EP 3 476 624 describes a composite comprising an elastomeric composition and a reinforcing element whose surface comprises brass and 1 to 10% by weight of one or more metals selected from cobalt, nickel, tin, indium, manganese, iron, bismuth, and molybdenum. The examples show that elastomeric compositions comprising an adhesion-promoting resin (resorcinol / hexa(methoxymethyl)melamine system, denoted H3M) and not comprising cobalt salts exhibit good long-term adhesion properties.

[0006] However, the combination of H3M with a phenolic compound such as resorcinol, the use of which is being restricted due to its HSE impact, produces formaldehyde during the curing of the rubber composition. Therefore, much research is focused on replacing this methylene acceptor / donor system with one that has a lower environmental impact. Document WO2017 / 103404, for example, illustrates a rubber composition that can be used for calendering reinforcement elements and includes a phloroglucinol / 1,4-benzene-dicarboxaldehyde system used at high levels to stiffen the rubber composition. This document does not address the issue of adhesion to the reinforcement elements.

[0007] Document WO2022 / 207998 describes the use of a phloroglucinol / 1,4-benzene-dicarboxaldehyde system at lower concentrations to improve the crack resistance of calendered compositions, with a moderate impact on adhesion, stiffness, and hysteresis performance. Although small, it would nevertheless be desirable to further minimize the impact on the properties of the compositions, particularly on stiffness and hysteresis, in order to reduce the contribution to rolling resistance while limiting as much as possible the increase in the plasticity of the raw compositions so as to simplify their processing.

[0008] Continuing its research, the applicant discovered a composite comprising at least one reinforcing element having a surface comprising a copper-zinc alloy, said reinforcing element being embedded in an elastomeric composition based on at least one diene elastomer, a reinforcing filler, a sulfur-based crosslinking system comprising a metal oxide, stearic acid or one of its derivatives and a vulcanization accelerator, and a phenol-aldehyde resin based on: - of at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl groups in meta positions relative to each other, the two ortho positions of at least one of the hydroxyl groups being unsubstituted, and - of at least one dialdehyde compound comprising two aldehyde functional groups,

[0009] wherein the phenol-aldehyde resin content ranges from 0.5 to 2 parts per million, and the mass ratio metallic oxide on stearic acid or one of its derivatives is greater than or equal to 8, preferably greater than 8. Detailed description of the invention Definitions

[0010] The carbon-containing compounds mentioned in the description may be of fossil origin or bio-based. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. This includes, in particular, polymers, plasticizers, fillers, etc. Composite

[0011] The invention relates to a composite comprising at least one reinforcing element having a surface comprising a copper, zinc alloy, said reinforcing element being embedded in an elastomeric composition.

[0012] By the expression composite "comprising at least one reinforcing element, said reinforcement being embedded in an elastomeric composition", it is to be understood that a composite comprising the reinforcing element and said composition, the composition having been able to react with the surface of the reinforcing element during the different phases of manufacturing the composite, in particular during the crosslinking of the composition or during the making of the composite before crosslinking of the composition, said reinforcing element being totally covered with said composition.

[0013] Said reinforcing element is a wire element. It may be entirely or partially metallic. A wire element is defined as an element having a length at least 10 times greater than the longest dimension of its cross-section, regardless of the shape of the latter: circular, elliptical, oblong, polygonal, and in particular rectangular, square, or oval. In the case of a rectangular cross-section, the wire element has the form of a strip.

[0014] Said reinforcing element comprises a metallic surface.

[0015] The metallic surface of the reinforcing element constitutes at least a part, and preferably the entire surface, of said element and is intended to come into direct contact with the elastomeric composition. Preferably, the reinforcing element is metallic, that is to say, made of a metallic material. Preferably, the reinforcing element is a steel reinforcing element coated with a metallic surface as defined herein.

[0016] The steel of the steel reinforcement element is preferably carbon steel or stainless steel. When the steel is carbon steel, its carbon content, expressed as a percentage by weight, is preferably between 0.01% and 1.2% or between 0.05% and 1.2%, or even between 0.2% and 1.2%, in particular between 0.4% and 1.1%. When the steel is stainless, it preferably contains at least 11% by weight of chromium and at least 50% by weight of iron.

[0017] The reinforcing element has a mechanical resistance ranging from 1000 MPa to 5000 MPa. Such mechanical resistances correspond to the steel grades commonly encountered in the field of tires, namely, grades NT (Normal Tensile), HT (High Tensile), ST (Super Tensile), SHT (Super High Tensile), UT (Ultra Tensile), UHT (Ultra High Tensile) and MT (Mega Tensile), the use of high mechanical resistances possibly allowing for improved reinforcement of the elastomeric composition in which the reinforcing element is embedded, and a reduction in the weight of the elastomeric composition thus reinforced.

[0018] The elastomeric composition encases the entire reinforcement element, with the possible exception of the cutting planes of the composite.

[0019] Preferably, the metallic surface of the reinforcing element comprises 55 to 75% by weight of copper.

[0020] Since some metals are subject to oxidation in contact with ambient air, the metal may be partially oxidized.

[0021] According to a preferred embodiment, the composite is a reinforced product comprising several reinforcing elements as defined above and a calendered elastomeric composition in which the reinforcing elements are embedded, the calendered elastomeric composition being the elastomeric composition of the composite according to the invention. According to this embodiment, the reinforcing elements are generally arranged side by side along a principal direction. For an application envisaged in a pneumatic tire, the composite can therefore constitute a reinforcing structure for the pneumatic tire.

[0022] The composite according to the invention may be in its raw state (before crosslinking of the elastomeric composition) or in its cured state (after crosslinking of the elastomeric composition). The composite is cured after contacting the reinforcing element(s) with the elastomeric composition described herein.

[0023] The composite can be manufactured by a process which comprises the following steps: - Creating two layers of the elastomeric composition of the composite according to the invention, - Sandwich the reinforcement element(s) between the two layers by placing it / them between the two layers, - If necessary, cook the composite.

[0024] Alternatively, the composite can be manufactured by depositing the reinforcing element onto a portion of a layer, the layer is then folded back on itself to cover the reinforcing element which is thus sandwiched along its entire length or part of its length.

[0025] The layers can be produced by calendering. During the curing of the composite, the elastomeric composition is cross-linked.

[0026] When the composite is intended to be used as a reinforcing reinforcement in a pneumatic tire, the baking of the composite generally takes place during the baking of the pneumatic tire. Diene elastomers

[0027] The composite according to the invention comprises an elastomeric composition based on at least one diene elastomer. By diene type elastomer, it should be understood that an elastomer which is derived at least in part (i.e. a homopolymer or a copolymer) from diene monomers (monomers bearing two carbon-carbon double bonds, conjugated or not).

[0028] These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". Generally, "essentially unsaturated" means a diene elastomer derived at least in part from conjugated diene monomers, having a proportion of diene motifs or units (conjugated dienes) greater than 15% (mole percent). Thus, diene elastomers such as butyl rubbers or EPDM-type diene-alpha-olefin copolymers do not fall under the preceding definition and can be described, in particular, as "essentially saturated" diene elastomers (low or very low proportion of diene motifs, always less than 15% (mole percent)). The diene elastomers included in the composition according to the invention are preferably essentially unsaturated.

[0029] The term diene elastomer, which can be used in compositions according to the invention, is particularly understood to mean: a. any homopolymer of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms; b. any copolymer of a diene, conjugated or not, having from 4 to 18 carbon atoms and at least one other monomer.

[0030] The other monomer may be ethylene, an olefin or a diene, conjugated or not.

[0031] Suitable conjugated dienes are those having from 4 to 12 atoms of carbon, in particular 1,3-dienes, such as 1,3-butadiene and isoprene.

[0032] Suitable olefins are vinylaromatic compounds having 8 to 20 carbon atoms and aliphatic α-monoolefins having 3 to 12 carbon atoms.

[0033] Suitable examples of vinylaromatic compounds include styrene, ortho-, meta-, para-methylstyrene, the commercial "vinyl-toluene" mixture, para-tert-butylstyrene.

[0034] As aliphatic α-monoolefins, acyclic aliphatic α-monoolefins having from 3 to 18 carbon atoms are particularly suitable.

[0035] The diene elastomer is preferably a diene elastomer of the highly unsaturated type, in particular a diene elastomer selected from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), polybutadienes (BR), butadiene copolymers, isoprene copolymers and mixtures of these elastomers. Such copolymers are more preferably selected from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR), isoprene-butadiene-styrene copolymers (SBIR), ethylene-butadiene copolymers (EBR) and mixtures of such copolymers.

[0036] The above diene elastomers can, for example, be block, statistical, sequenced, microsequenced, and be prepared in dispersion or in solution; they can be coupled and / or star-shaped or functionalized with a coupling and / or star-shaped or functionalizing agent, for example epoxy-coated.

[0037] Preferably, the elastomeric composition of the composite according to the invention comprises at least 50 parts per annum, preferably at least 70 parts per annum, and preferably at least 90 parts per annum of at least one isoprene elastomer. In a highly preferred embodiment, the elastomeric composition of the composite according to the invention comprises 100 parts per annum of at least one isoprene elastomer.

[0038] By "isoprene elastomer" is meant a homopolymer or a copolymer of isoprene, in other words a diene elastomer selected from the group consisting of natural rubber (NR) which can be plasticized or peptized, synthetic polyisoprenes (IR), the various isoprene copolymers, in particular isoprene-styrene copolymers (SIR), isoprene-butadiene copolymers (BIR) or isoprene-butadiene-styrene copolymers (SBIR), and mixtures of these elastomers.

[0039] Preferably, the isoprene elastomer is chosen from the group consisting of synthetic polyisoprenes, natural rubber, isoprene copolymers and mixtures thereof, preferably from the group consisting of natural rubber, polyisoprenes comprising a cis 1,4 linkage mass percentage of at least 90%, more preferably at least 98%, relative to the mass of the isoprene elastomer and mixtures thereof. Most preferably, the isoprene elastomer is natural rubber. Reinforcing load

[0040] The elastomeric composition of the composite according to the invention comprises a reinforcing filler. Any type of reinforcing filler known for its ability to reinforce an elastomeric composition usable for the manufacture of pneumatic tires can be used, for example an organic filler such as carbon black, a reinforcing inorganic filler such as silica, or a blend of these two types of filler, in particular a blend of carbon black and silica.

[0041] All carbon blacks are suitable as carbon blacks, particularly those of the HAF, ISAF, and SAF types conventionally used in tires (so-called tire-grade blacks). Among these, carbon blacks of the 100, 200, or 300 series (ASTM grades) are particularly suitable, such as NI 15, N134, N234, N326, N330, N339, N347, and N375, or, depending on the intended application, blacks of higher series (e.g., N550, N660, N683, N772). Carbon blacks could, for example, already be incorporated into an isoprene elastomer in the form of a masterbatch (see, for example, applications WO 97 / 36724 or WO 99 / 16600). The specific surface area BET of carbon blacks is measured according to standard D6556-10 [multipoint method (minimum 5 points) - gas: nitrogen - relative pressure range P / P0: 0.1 to 0.3].

[0042] In the present application, "reinforcing inorganic filler" should be understood, by definition, as any inorganic or mineral filler (regardless of its color and whether of natural or synthetic origin), also called "white" filler, "light" filler or even "non-black filler" as opposed to carbon black, capable of reinforcing on its own, without any other means than an intermediate coupling agent, a rubber composition intended for the manufacture of pneumatic tires, in other words, capable of replacing, in its reinforcing function, a conventional carbon black of pneumatic grade; such a filler is generally characterized, in a known way, by the presence of hydroxyl groups (-OH) on its surface.

[0043] Suitable inorganic reinforcing fillers include mineral fillers of the siliceous type, in particular silica (SiO2), or of the aluminous type, in particular alumina (Al2O3). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or fumed silica having a BET surface area and a CTAB specific surface area both less than 450 m2 / g, preferably from 30 to 400 m2 / g. Examples of highly dispersible precipitated silicas (known as "HDS") include "Ultrasil 7000" and "Ultrasil 7005" silicas from Degussa, "Zeosil 1165MP", "1135MP" and "1115MP" silicas from Rhodia, "Hi-Sil EZ150G" silica from PPG, "Zeopol 8715", "8745" and "8755" silicas from Huber, and high specific surface area silicas as described in application WO 03 / 16837.

[0044] The physical state of the reinforcing inorganic filler is irrelevant, whether it is in the form of powder, microbeads, granules, spheres, or any other suitable densified form. Of course, the term "reinforcing inorganic filler" also includes mixtures of different reinforcing inorganic fillers, in particular highly dispersible siliceous and / or aluminous fillers.

[0045] The reinforcing inorganic filler used, in particular if it is silica, preferably has a BET surface area of ​​between 45 and 400 m2 / g, more preferably between 60 and 300 m2 / g.

[0046] In a preferred arrangement, the elastomeric composition of the composite according to the invention comprises from 10 to 100 parts per annum, more preferably from 10 to 80 parts per annum, and preferably from 10 to 70 parts per annum, of carbon black, the optimum being known to differ depending on the particular applications intended: the level of reinforcement expected on a bicycle tire, for example, is of course lower than that required on a tire suitable for sustained high-speed driving, for example, a motorcycle tire, a passenger car tire, or a commercial vehicle tire such as a truck. In a preferred arrangement, the reinforcing filler comprises mainly carbon black, and preferably is made of carbon black.

[0047] Preferably, the elastomeric composition of the composite according to the invention comprises from 10 to 150 parts per liter, preferably from 10 to 100 parts per liter, of silica. In a preferred arrangement, the reinforcing filler comprises predominantly silica and preferably less than 5 parts per liter of carbon black, preferably less than 3 parts per liter of carbon black, preferably less than 2 parts per liter of carbon black, and preferably no carbon black. The composition of the composite according to the invention, in this preferred arrangement, exhibits excellent properties in terms of processability, hysteresis, and stiffness.

[0048] To couple the reinforcing inorganic filler to the elastomer, optionally a coupling agent (or bonding agent) at least bifunctional can be used in a known manner to ensure a sufficient connection, of a chemical and / or physical nature, between the inorganic filler (surface of its particles) and the elastomer, in particular organosilanes, or bifunctional polyorganosiloxanes.

[0049] In particular, polysulfide silanes, called "symmetric" or "asymmetric" depending on their particular structure, can be used, as described for example in applications WO03 / 002648 (or US 2005 / 016651) and WO03 / 002649 (or US 2005 / 016650).

[0050] By way of examples of polysulfurized silanes, particular mention will be made of the polysulfides (in particular disulfides, trisulfides or tetrasulfides) of bis-(alkoxyl(Cl- C4)-alkyl(Cl-C4)silyl-alkyl(Cl-C4)), such as bis(3-trimethoxysilylpropyl) or bis(3-triethoxysilylpropyl) polysulfides. Among these compounds, bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT, with the formula [(C2H5O)3Si(CH2)3S2]2, or bis-(triethoxysilylpropyl) disulfide, abbreviated TESPD, with the formula [(C2H5O)3Si(CH2)3S]2, are used in particular. We will also cite as preferential examples the polysulfides (in particular disulfides, trisulfides or tetrasulfides) of bis-(monoalkoxyl(Cl-C4)-dialkyl(Cl-C4)silylpropyl), more particularly the tetrasulfide of bis-monoethoxydimethylsilylpropyl as described in US patent application 2004 / 132880.

[0051] As a coupling agent other than polysulfurized alkoxysilane, mention shall be made in particular of bifunctional POS (polyorganosiloxanes) or hydroxysilane polysulfides as described in patent applications WO 02 / 30939 and WO 02 / 31041, or silanes or POS bearing azo-dicarbonyl functional groups, as described for example in patent applications WO 2006 / 125532, WO 2006 / 125533, WO 2006 / 125534.

[0052] In the elastomeric compositions according to the invention, the content of coupling agent is preferably in a range of 5 to 18% by weight relative to the amount of silica, preferably in a range of 8 to 12% by weight relative to the amount of silica.

[0053] A person skilled in the art will understand that, as an equivalent charge to the reinforcing inorganic charge described in this paragraph, a reinforcing charge of another nature, in particular organic, could be used, provided that this reinforcing charge is covered with an inorganic layer such as silica, or has functional sites on its surface, in particular hydroxyl sites, allowing the bond to be established between the charge and the elastomer in the presence or not of a coating or coupling agent. Crosslinking system

[0054] The elastomeric composition of the composite according to the invention comprises a sulfur-based crosslinking system including a metal oxide, stearic acid or one of its derivatives, and a vulcanization accelerator. This is referred to as a vulcanization system. The sulfur may be supplied in any form, in particular as molecular sulfur, or as a sulfur-donating agent.

[0055] Sulfur is used at a rate preferably between 4 and 12 parts per cent.

[0056] The vulcanization accelerator is used at a preferential rate such that the sulfur / vulcanization accelerator mass ratio is strictly greater than 3, preferably strictly greater than 3.1.

[0057] Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur can be used as an accelerator. including accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds.

[0058] The mass ratio of metal oxide to stearic acid or one of its derivatives in the crosslinking system is greater than or equal to 8, preferably greater than 8. The metal oxide is preferably zinc oxide.

[0059] The crosslinking system may also optionally include a vulcanization retarder. Phenolaldehyde resin

[0060] According to the invention, the elastomeric composition of the composite according to the invention is based on a phenol-aldehyde resin based on: • of at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl groups in meta positions relative to each other, the two ortho positions of at least one of the hydroxyl groups being unsubstituted, and • of at least one dialdehyde compound comprising two aldehyde functional groups.

[0061] The phenol-aldehyde resin content in the elastomeric composition of the composite according to the invention ranges from 0.5 to 2 parts per million. Phenol-aldehyde resin content refers to the sum of the aromatic polyphenol and aldehyde compound contents based on the phenol-aldehyde resin. These levels allow the resin not only to perform its role as an adhesion promoter without significantly altering the rigidity of the crosslinked mixture, but also, in combination with the metal oxide to stearic acid mass ratio or one of its derivatives, to obtain improved performance in terms of rigidity and hysteresis behavior, while ensuring good processability of the raw composition.

[0062] Aromatic polyphenol

[0063] In one embodiment, the aromatic polyphenol may be a simple molecule comprising one or more aromatic rings, at least one of these aromatic rings, or even each aromatic ring, bearing at least two hydroxyl groups in meta positions relative to each other, the two ortho positions of at least one of the hydroxyl groups being unsubstituted. Such a simple molecule does not comprise a repeating motif.

[0064] In another embodiment, the aromatic polyphenol may be a precondensed resin based on: • of at least one aromatic polyphenol, comprising at least one aromatic ring bearing at least two hydroxyl groups in meta positions relative to each other, the two ortho positions of at least one of the hydroxyl groups being unsubstituted; and • of at least one dialdehyde compound comprising two aldehyde groups.

[0065] Such a pre-condensed aromatic polyphenol-based resin conforms to the invention and, unlike the simple molecule described above, comprises a repeating motif. In this case, the repeating motif comprises at least one aromatic ring bearing at least two hydroxyl groups in a meta position relative to each other.

[0066] In another embodiment, the aromatic polyphenol is a mixture of an aromatic polyphenol forming a simple molecule and a pre-condensed resin based on aromatic polyphenol.

[0067] In the following particular embodiments, the aromatic ring(s) of the aromatic polyphenol are described. For clarity, the "aromatic polyphenol" is described therein in its simple molecular form. This aromatic polyphenol can then be condensed and will partly define the repeating motif.

[0068] In a preferred embodiment, the aromatic core of the aromatic polyphenol has three -OH groups in meta positions relative to each other.

[0069] Preferably, the two ortho positions of each -OH group of the aromatic polyphenol are unsubstituted. This means that the two carbon atoms located on either side (in ortho positions) of the carbon atom bearing the -OH group each bear a single hydrogen atom.

[0070] Even more preferably, the remainder of the aromatic ring of the aromatic polyphenol is unsubstituted. This means that the other carbon atoms of the remainder of the aromatic ring (those other than the carbon atoms bearing the -OH groups) bear a single hydrogen atom.

[0071] In one embodiment, the aromatic polyphenol comprises several aromatic rings, at least two of them each bearing at least two -OH groups in meta positions relative to each other, the two ortho positions of at least one of the -OH groups of at least one aromatic ring being unsubstituted.

[0072] In a preferred embodiment, at least one of the aromatic rings of the aromatic polyphenol has three -OH groups in meta positions relative to each other.

[0073] Preferably, the two ortho positions of each -OH group of at least one aromatic ring are unsubstituted.

[0074]

[0075]

[0076]

[0077] Even more preferentially, the two ortho positions of each -OH group of each aromatic ring are unsubstituted. Advantageously, the aromatic ring or rings of the aromatic polyphenol are benzene rings. As an example of an aromatic polyphenol containing a single aromatic ring, we can cite in particular resorcinol and phloroglucinol, with respective formulas I and II: (I) HO QH (II) HO "OH As examples, in the case where the aromatic polyphenol has several aromatic rings, at least two of these aromatic rings, identical or different, are chosen from those with general formulas: OH HO (Ill-a) 'OH

[0078]

[0079]

[0080] (Ill-b) HO (III-c) OH OH OH (Ill-d)

[0081] wherein the symbols Zb Z2, identical or different if there are several on the same aromatic ring, represent an atom (for example carbon, sulfur or oxygen) or a bonding group by definition at least divalent, which links at least these two aromatic rings to the rest of the aromatic polyphenol.

[0082] Another example of an aromatic polyphenol is 2,2',4,4'-tetrahydroxydiphenyl sulfide, having the following formula: (IV)

[0083] Another example of an aromatic polyphenol is 2,2',4,4'-tetrahydroxydiphenyl benzophenone, with the following formula: (V)

[0084] It is noted that each compound IV and V is an aromatic polyphenol comprising two aromatic rings (of formula III-c) each of which carries at least two (in this case two) -OH groups in meta position relative to each other.

[0085] It is noted that in the case of an aromatic polyphenol comprising at least one aromatic ring conforming to formula Ill-b, the two ortho positions of each -OH group of at least one aromatic ring are unsubstituted. In the case of an aromatic polyphenol comprising several aromatic rings conforming to formula IH-b, the two ortho positions of each -OH group of each aromatic ring are unsubstituted.

[0086] According to one embodiment of the invention, the aromatic polyphenol is selected from the group consisting of resorcinol I, phloroglucinol II, 2,2',4,4'-tetrahydroxydiphenyl sulfide IV, 2,2',4,4'-tetrahydroxybenzophenone V, and mixtures of these compounds. In a particularly advantageous embodiment, the aromatic polyphenol is phloroglucinol II.

[0087] Dialdehyde compound

[0088] Preferably, the dialdehyde compound is an aromatic dialdehyde compound. Such an aldehyde is very advantageous because it avoids the production of formaldehyde, unlike conventional methylene donors. A dialdehyde aromatic is a compound comprising at least one aromatic ring, this aromatic ring bearing at least two aldehyde functions.

[0089] In a preferred arrangement, the aromatic dialdehyde compound is an aldehyde of formula A: (HAS) H

[0090] in which X comprises N, S or O and R represents -CHO.

[0091] According to a preferred embodiment, X represents O. The aromatic dialdehyde compound then has the formula Bb: / O. (Bb) HH

[0092] In this embodiment, the aromatic dialdehyde compound is preferably 2,5-furanedicarboxaldehyde.

[0093] In another preferred embodiment, X comprises N. In a variant of this embodiment, X represents NH. The aromatic dialdehyde compound then has the formula Ca: H

[0094] Preferably, in this variant, the aromatic dialdehyde compound is 2,5-IH-pyrroledicarboxaldehyde.

[0095] In another variant of this embodiment, X represents NR1 with RI representing a radical chosen from the group consisting of alkyl, aryl, arylalkyl, alkylaryl, cycloalkyl radicals. The aromatic dialdehyde compound then has the formula Cb: RI (Cb) H

[0096] In another preferred embodiment, X comprises S. In a variant of this embodiment, X represents S and the aromatic dialdehyde compound then has the formula Da: H

[0097] Preferably, in this variant, the aromatic dialdehyde compound is 2,5-thiophenedic arboxaldéhy de.

[0098] In another variant of this embodiment, X represents SR2 with R2 representing a radical chosen from the group consisting of alkyl, aryl, arylalkyl, alkylaryl, and cycloalkyl radicals. The aromatic dialdehyde compound then has the formula Db: R2 (dB) HAS rW H

[0099] In another variant of this embodiment, X represents R3-S-R2, with R2 and R3 each independently representing a radical chosen from the group consisting of alkyl, aryl, arylalkyl, alkylaryl, and cycloalkyl radicals. The aromatic dialdehyde compound then has the formula De: R2s R3 (From) H

[0100] In another variant of this embodiment, X represents S=O. The aromatic dialdehyde compound then has the formula Dd: H

[0101] In another variant of this embodiment, X represents O=S=O. The aromatic dialdehyde compound then has the formula De: , O (Of) rV H

[0102] Among the various embodiments described above, preference will be given to those embodiments and variants in which X represents NH, S, or O. In these embodiments of realization and variants, we will preferably have R, which represents the -CHO group, in position 5 and the -CHO group in position 2 on the aromatic ring.

[0103] Most preferably, the aromatic aldehyde is chosen from the group consisting of 1,4-benzene-dicarboxaldehyde, 1,3-benzene-dicarboxaldehyde, 2,5-furanedicarboxaldehyde and mixtures of these compounds, and most preferably 1,4-benzene-dicarboxaldehyde. Various additives

[0104] The elastomeric composition of the composite according to the invention may also include all or part of the usual additives commonly used in elastomeric compositions for the manufacture of pneumatic tires, such as plasticizers or extension oils, whether the latter are aromatic or non-aromatic, pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents.

[0105] Preferably, the elastomeric composition of the composite according to the invention does not comprise cobalt salts or comprises less than 1 part per annum, preferably less than 0.5 parts per annum, preferably less than 0.2 parts per annum, and preferably does not comprise any cobalt salts at all. Indeed, the properties of the elastomeric composition of the composite according to the invention make it possible to achieve good adhesion properties without the need to use such salts.

[0106] Thus, the specific characteristics of the elastomeric composition and the metallic surface of the composite according to the invention make it possible to achieve and maintain excellent performance, in particular in terms of adhesion, rigidity, hysteretic losses and resistance to cracking as well as good processability of the raw compositions. Finished or semi-finished article and pneumatic

[0107] The invention also relates to a finished or semi-finished article comprising a composite according to the invention. The finished or semi-finished article may be any article comprising a composite. Examples include, but are not limited to, conveyor belts, pneumatic or non-pneumatic tires.

[0108] The pneumatic tire, another object of the invention, has as its essential characteristic the inclusion of the composite according to the invention. The pneumatic tire may be in its raw state (before crosslinking of the elastomeric composition) or in its cured state (after crosslinking of the elastomeric composition). Generally, during the manufacture of the pneumatic tire, the composite is deposited in its raw state (i.e., before crosslinking of the elastomeric composition) within the structure of the pneumatic tire prior to the curing step.

[0109] The invention relates particularly to pneumatic tires intended to equip motor vehicles of the passenger car type, SUVs ("Sport Utility Vehicles"), or two wheels (in particular motorcycles), or aircraft, or even industrial vehicles chosen from among vans, "Heavy Goods Vehicles", i.e. metro, buses, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering vehicles, and others. Examples Preparing the test tubes

[0110] The following tests are carried out as follows: the diene elastomer, the reinforcing filler, and the various other ingredients, including phloroglucinol (with the exception of the vulcanizing system and terephthalaldehyde when a resin is present in the composition), are successively introduced into an internal mixer (final filling level: approximately 70% by volume) with an initial tank temperature of approximately 60°C. A thermomechanical process (non-productive phase) is then carried out in a single step, lasting approximately 3 to 4 minutes in total, until a maximum "drop" temperature of 165°C is reached.

[0111] The mixture thus obtained is recovered, cooled, and then sulfur, the accelerator (sulfenamide), the retarder, and terephthalaldehyde when a resin is present in the composition are incorporated on a mixer (homo-finisher) at 30 °C, mixing everything (productive phase) for an appropriate time (for example between 5 and 12 min).

[0112] The compositions thus obtained are then calendered into plates (thickness of 2 to 3 mm) or thin sheets of rubber and are then either subjected to a baking step before measuring their physical or mechanical properties or used to make the measuring specimens for the Tan(d) max tests at 60°C and tensile test as described below. Measurement methods

[0113] Mooney Plasticity

[0114] The Mooney plasticity test is performed according to the following principle and in accordance with ASTM D-1646. The raw composition (before the baking step) is molded in a cylindrical chamber heated to a given temperature, usually 100°C. After one minute of preheating, an L-type rotor rotates within the specimen at 2 revolutions per minute, and the torque required to maintain this rotation is measured after 4 minutes of rotation. The Mooney plasticity (ML 1+4) is expressed in "Mooney units" (MU, with 1 MU = 0.83 Newton-meters).

[0115] The results are expressed on a scale of 100, with 100 being assigned to the control. A result greater than 100 indicates that the composition of the example considered presents a Mooney index higher than that of the control. A result below 100 is therefore favorable for improving the processability of the raw composition.

[0116] Tan(d) max at 60°C

[0117] The dynamic loss tan(d)max at 60°C is a dynamic property well known to those skilled in the art and is measured on a Metravib VA4000 or DMA+450 type viscoanalyzer using specimens comprising a baked composition. The response of the specimens subjected to a sinusoidal alternating simple shear load at a frequency of 10 Hz is recorded under determined temperature conditions (here 60°C) according to ASTM DI349-99. A strain amplitude sweep is performed from 0.1% cc to 100% cc (forward cycle), then from 100% cc to 0.1% cc (reverse cycle), cc meaning peak-to-peak. The specimen is of cylindrical cross-section as described in ASTM D 5992-96 (version reapproved in 2011, originally approved in 1996) in Figure X2.1 (circular embodiment) and has a diameter of 10 mm [0 to +0.04 mm] and a thickness of 2 mm [1.83-2.33].The tangent tan(d) of the phase angle d between the force exerted on the sample and its displacement represents a dynamic loss and is equal to the ratio G” / G’. The maximum value tan(d) max of the tangent tan(d) of the phase angle d observed on the deformation return cycle is recorded.

[0118] The results are expressed on a base of 100, with the value 100 assigned to the control. A result greater than 100 indicates that the composition of the example considered has a tan(d) value greater than that of the control. A result less than 100 is therefore favorable because it reflects a lower hysteresis.

[0119] Tensile tests

[0120] The measurement is carried out on dumbbell-type test specimens, 2.5mm thick, whose dimensions are shown in [Fig.1].

[0121] The nominal secant modulus at X% elongation is called the modulus of the mixture measured during a uniaxial tensile test, at a strain value of X / 100. X can take the values ​​10, 50, 100 and 300. If X = 10, we therefore measure the MA 10 modulus, that is to say the nominal secant modulus at 10% strain.

[0122] For this, a constant uniaxial tensile speed of 500mm / min is imposed on the specimen, and its elongation and force are measured.

[0123] The measurement is carried out using an INSTRON type tensile testing machine, at a temperature of 60°C and a relative humidity of 50% (ISO 23529 standard). The measurement and results processing conditions for determining elongation and stress are as described in standard NF ISO 37:2012-03.

[0124] Before proceeding with the measurement, a pre-accommodation of the sample is performed. The imposed displacement level depends on the measured modulus (MA10, MA50, etc.): 9mm for an MA10, 45mm for an MA50, 90mm for MA100 and 270mm for MA300.

[0125] The nominal stress F / SO is determined, with F being the force measured for a strain of X / 100, SO the initial cross-section of the specimen, and the secant modulus of elasticity at X% elongation is calculated by dividing this stress value by the strain value (Delta / SO): A [MPaJ - SJmm2] [A] [MPaJ - SJmm2] [ALM

[0126] The results are expressed on a scale of 100, with the value 100 assigned to the control. A result greater than 100 indicates that the composition of the example considered exhibits greater rigidity than the control. Results

[0127] The tables below show the results of measurements carried out on different mixtures. Mixture T1 serves as a control for mixture C1, mixture T2 serves as a control for mixtures C2 and C3, mixture T3 serves as a control for mixtures C4 and C5, and mixture T4 serves as a control for mixtures C6 and C7.

[0128] The mixtures Tl, Cl, T2, C2 and C3 are cooked at 140°C for 50 min.

[0129] Mixtures T3, C4, C5, T4, C6 and C7 are cooked at 160°C for 15 minutes.

[0130] [Tables 1] Tl Cl T2 C2 C3 T3 C4 C5 T4 C6 C7 HR 190 100 100 100 100 100 100 100 100 100 100 N375 QQ 0 0 0 31 31 31 0 0 0 N5S0 S 0 0 0 0 34 34 34 p, P 0 N326 YES YES 47 47 47 0 3 3 3 3 0 SL 120MP 0 0 GGGG 0 0 50 50 50 Dr / sitane 0 0 0 0 0 0 0 0 6.5 6.5 6.5 DPG Q o 0 0 0 0 0 0 0.9 0.9 0.9 Anti-oxidant iSPPD) 1.8 1.8 1.5 1.5 1.5 2 2 2 2 2 2 Acide stearique 0.6 0.6 0.9 0.9 0.9 0.6 0.6 0.6 0.5 0.5 0.5 Oxyde de Sic 9.3 9.3 7.5 7.5 7.5 S 8 8 8 8 B Phloroglucinol 1 0.5 0.5 0.2.5 0.5 0.25 0.5 9.25 T é f ephta iatdé hyd é 2 1 9 :0.5 9 0.5 9 0.5 Soufre 7 7 5 5 5 4 4 4 5 5 5 A ccé ié ra te ur TB BS 0 0 0 0 0 0.8 0.8 0.8 1.5 1.5 1.5 Accélérateur DC8S 0.9 0.9 0.8 0.8 0.8 0 0 0 0 0 0 Retardateur CTP 0.0 0.0 0.2 0.2 0.2 ■ 0.2 Q 0.2 0.0 0.0 0.0 ZnO / Ac stéa rtq ue 15.5 15.5 8.3 8.3 8.3 13.3 13.3 13.3 : 16.0 16.0 16.0 S / accélérateur 7.5 7.5 5.6 5.6 5.6 5.5 5.5 5.5 3.2 3.2 3.2 Results [Base 100} Mooney 100 92 100 80 75 100 93 91 ISO 52 46 MA1O0 100 102 100 101 97 100 114 119 wo 120 128 tan(d) max {6QSC) 100 100 100 95 95 100 94 88 100 90 90 100 100 100 98 96 100 106 139 130 110 113 .

[0131] Composition Cl corresponds to a reduced resin content compared to its control Tl. Processability and rigidity are improved without impacting hysteresis.

[0132] Compositions C2 and C3 correspond to a reduced resin content compared to their control T2. Processability is further improved as the resin content decreases, and in all cases, hysteresis is improved. For composition C3, the stiffness is slightly lower than that of the control but remains very close to it.

[0133] Compositions C4 and C5 correspond to a reduced resin content compared to their control T3. Processability, rigidity and hysteresis are all three improved compared to the control T3.

[0134] Compositions C6 and C7 correspond to a reduced resin content compared to their control T4. Processability, rigidity and hysteresis are all three significantly improved compared to the control T4.

Claims

Demands

1. Composite comprising at least one reinforcing element having a surface comprising a copper-zinc alloy, said reinforcing element being embedded in an elastomeric composition based on at least one diene elastomer, a reinforcing filler, a sulfur-based crosslinking system comprising a metal oxide, stearic acid or one of its derivatives and a vulcanization accelerator, and a phenol-aldehyde resin based on: - at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functions in meta positions relative to each other, the two ortho positions of at least one of the hydroxyl functions being unsubstituted, and - at least one dialdehyde compound comprising two aldehyde functions, in which the phenol-aldehyde resin content is from 0.5 to 2 pc, and the metal oxide to stearic acid or one of its derivatives mass ratio is greater than or equal to 8.

2. Composite according to the preceding claim in which the dialdehyde compound comprises at least one aromatic ring.

3. Composite according to one of the two preceding claims wherein the dialdehyde compound is selected from 1,4-benzene-dicarboxaldehyde and 1,3-benzene-dicarboxaldehyde.

4. Composite according to any one of the preceding claims wherein the sulfur-based crosslinking system comprises from 4 to 12 parts per annum of sulfur.

5. Composite according to any one of the preceding claims wherein the sulfur-to-vulcanization accelerator mass ratio is strictly greater than 3, preferably strictly greater than

6. JJ J- • Composite according to any one of the preceding claims in which the surface of the reinforcing element comprises from 55 to 75% by weight of copper.

7. Composite according to any one of the preceding claims wherein the elastomeric composition comprises at least 50 parts, preferably at least 70 parts, preferably at least 90 parts of at least one isoprene elastomer, and most preferably 100 parts of at least one isoprene elastomer.

8. Composite according to any one of the preceding claims wherein the elastomeric composition does not comprise cobalt salts or comprises less than 1 pc, preferably less than 0.5 pc, preferably less than 0.2 pc and preferably does not comprise cobalt salts.

9. Composite according to any one of the preceding claims wherein the reinforcing filler of the elastomeric composition comprises predominantly carbon black.

10. Composite according to any one of claims 1 to 8 wherein the reinforcing filler of the elastomeric composition comprises predominantly silica.

11. Composite according to the preceding claim wherein the elastomeric composition comprises a silica coupling agent, the content of the coupling agent being in a range of 5 to 18% by weight relative to the amount of silica, preferably in a range of 8 to 12% by weight relative to the amount of silica.

12. Composite according to claim 11 in which the elastomeric composition comprises less than 5 pc of carbon black, preferably less than 3 pc of carbon black, preferably less than 2 pc of carbon black and preferably does not comprise carbon black.

13. Finished or semi-finished article comprising a composite according to any one of the preceding claims.

14. Pneumatic bandage comprising a composite according to any one of claims 1 to 12.

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