Elastomer composition containing phenolic compounds and monosaccharide family compounds

Abstract

The present invention relates to a rubber composition based on at least one elastomer, at least one phenolic compound and at least one compound of the monosaccharide family, wherein the aromatic nucleus of said phenolic compound is substituted with at least one hydrocarbon substituent and wherein the molar mass of said phenolic compound is at most equal to 1000 g / mol.

Description

[Technical Field]

[0001] The present invention relates to an elastomer-based rubber composition, a composite material containing the composition, a finished or semi-finished product containing the composition or the composite material, and a pneumatic tire containing the composition or the composite material. [Background technology]

[0002] The plies used to reinforce pneumatic tires typically consist of a rubber mixture and reinforcing cords, which are often metallic and coated with brass. Since these plies are subjected to high stress during the rotation of the pneumatic tire, the adhesion between the rubber mixture and the reinforcing elements is considered a crucial characteristic. Adhesion generally requires specific formulations for rubber mixtures, particularly high sulfur and zinc oxide content, small amounts of stearic acid and cobalt salts, and the use of retarding agents. However, these high-sulfur vulcanization systems pose a significant constraint during the manufacturing of semi-finished products, especially in order to avoid premature crosslinking. Therefore, it is advantageous for manufacturers of pneumatic tires to formulate a rubber composition that allows for the omission of sulfur from the composition while simultaneously enabling good adhesion to the reinforced cable. International applications 2017 / 081387 and 2017 / 081388 present rubber compositions and composite materials based on a polymer matrix containing a functional diene polymer. This functional diene polymer supports at least one aromatic group, which is substituted with at least two adjacent hydroxyl functional groups. Crosslinking of the rubber composition is carried out using a vulcanization system or a system based on one or more peroxide compounds. Good adhesion properties of the rubber composition to metals are obtained, but the use of grafted polymers is required. Therefore, a simpler solution for improving adhesion properties would be advantageous. Japanese Patent Publication No. 2011252107 describes a rubber composition that adheres well to metals, and this composition comprises a diene elastomer and a cobalt salt. Gallic acid or gallic acid hydrate promotes the dissolution of the cobalt salt. The composition is crosslinked with a sulfur-based system. This composition has good adhesive properties, but uses both sulfur and a cobalt salt.

[0003] International application No. 2019 / 122586 teaches a rubber composition comprising a specific phenol compound, in which the crosslinking system is sulfur-free and has excellent adhesive properties to metal reinforcers. International applications 2020 / 058613 and 2020 / 058614 describe rubber compositions containing high molar mass polyphenol compounds that exhibit excellent adhesion properties to metal reinforcers. However, this type of compound can be expensive and therefore less practical for use in pneumatic tires. Through continuous research, the applicant has discovered a rubber composition that enables the resolution of the aforementioned problems and exhibits very good performance with respect to adhesion to metal supports. [Overview of the project]

[0004] The present invention relates to at least one embodiment as described below. 1. A rubber composition comprising at least one diene elastomer, a reinforcing filler, a crosslinking system based on at least one or more radical polymerization initiators, and at least one phenol compound having a molar mass equal to 1000 g / mol, wherein the hydrocarbon group is interrupted and / or substituted by an oxygen atom, and may be interrupted and / or substituted by one or more heteroatoms, and the rubber composition further comprises at least one compound of a monosaccharide family selected from aldoses and ketoses. 2. A rubber composition according to Embodiment 1, wherein the phenol group of the phenol compound is substituted with at least two hydrocarbon groups which may be interrupted and / or substituted by one or more heteroatoms, at least one of the hydrocarbon groups is interrupted and / or substituted by an oxygen atom, and the two hydrocarbon groups can form a ring together with the carbon atoms of the aromatic ring of the phenol group to which they are bonded, which may be interrupted and / or substituted by one or more heteroatoms. 3. Phenol compounds have general formula (I)

[0005] [ka] [In the formula, - G1 represents a hydroxyl, carboxyl, or alkoxy group, or a hydrogen atom. - G2 represents a hydroxyl, carboxyl, or carbonyl group, or a hydrogen atom. - G3 represents a hydroxyl, carboxyl, hydrogenocarbonyl, carboxyalkyl, carboxyalkylene, alkoxy, amino, aminoalkyl, amide, or vinyl group, or a hydrogen atom. This corresponds to, At least one of substituents G1 to G3 contains an oxygen atom, the molar mass of the phenol compound is equal to a maximum of 1000 g / mol, and the rubber composition further comprises at least one compound from the monosaccharide family selected from aldoses and ketoses. A rubber composition according to any one of Embodiments 1 to 2. 4. A rubber composition according to any one of Embodiments 1 to 3, wherein the phenol compound is substituted with at least two hydroxyl groups. 5. A rubber composition according to any one of Embodiments 1 to 4, wherein the phenol compound is substituted with at least one carboxyl group.

[0006] 6. A rubber composition according to any one of Embodiments 1 to 5, wherein the phenol compound is substituted at least at the para position relative to the hydroxyl group. 7. A rubber composition according to Embodiment 6, wherein the phenol compound is substituted with a carboxyl group at the para position relative to the hydroxyl group. 8. A rubber composition according to any one of Embodiments 3 to 7, wherein G1, G2, and G3 are independently selected from hydroxyl and carboxyl groups and hydrogen atoms, and preferably independently selected from hydroxyl and carboxyl groups. 9. A composition according to any one of Embodiments 1 to 8, wherein the molar mass of the phenol compound is less than 800 g / mol, preferably less than 600 g / mol, very preferably less than 400 g / mol, and very preferably less than 220 g / mol. 10. A rubber composition according to Embodiment 1, wherein the phenol compound is selected from 1,4-dihydroxy-2-naphthoic acid, curcumin, resveratrol, daidzein, genistein, apigenin, umbelliferone, l-tyrosine, guaiacol, 2-hydroxy-4-methoxybenzaldehyde, isovanillin, salicylic acid, acetaminophen, 4-hydroxybenzaldehyde, caffeic acid, 5-aminosalicylic acid, 3,4-dihydroxybenzaldehyde, 2,5-dihydroxyterephthalic acid, vanillin, 2,5-dihydroxybenzoic acid, gallic acid, protocatechuic acid, 4-hydroxyisophthalic acid, 2,3,4-trihydroxybenzoic acid, 3-O-methylgallic acid, 4,5-dihydroxyphthalic acid, 2,4,5-trihydroxybenzoic acid, and mixtures thereof.

[0007] 11. A rubber composition according to Embodiment 1, wherein the phenol compound is selected from acetaminophen, 4-hydroxybenzaldehyde, caffeic acid, 5-aminosalicylic acid, 3,4-dihydroxybenzaldehyde, 2,5-dihydroxyterephthalic acid, vanillin, 2,5-dihydroxybenzoic acid, gallic acid, protocatechuic acid, 4-hydroxyisophthalic acid, 2,3,4-trihydroxybenzoic acid, 3-O-methylgallic acid, 4,5-dihydroxyphthalic acid, 2,4,5-trihydroxybenzoic acid, and mixtures thereof. 12. A rubber composition according to Embodiment 1, wherein the phenol compound is selected from caffeic acid, gallic acid, protocatechuic acid, 4-hydroxyisophthalic acid, 2,3,4-trihydroxybenzoic acid, 3-O-methylgallic acid, 4,5-dihydroxyphthalic acid, 2,4,5-trihydroxybenzoic acid, and mixtures thereof, and is preferably selected from caffeic acid, gallic acid, and protocatechuic acid. 13. A composition according to any one of Embodiments 1 to 12, wherein the content of the phenol compound is between 0.1 and 25 phr. 14. A composition according to any one of Embodiments 1 to 13, wherein the compound of the monosaccharide family is selected from trioses, tetroses, pentoses, and hexoses, preferably from pentoses and hexoses.

[0008] 15. A composition according to Embodiment 14, wherein the compound of the monosaccharide family is selected from fructose, psicose, sorbose, tagatose, allose, altrose, glucose, mannose, growth, idose, galactose, and talose, preferably selected from fructose, glucose, mannose, and galactose, and very preferably selected from fructose and glucose. 16. A composition according to any one of Embodiments 1 to 15, wherein the content of monosaccharide family compounds is between 0.1 and 15 phr, preferably between 0.1 and 10 phr. 17. A composition according to any one of Embodiments 1 to 16, which does not contain a cobalt salt or contains less than 1 phr of one cobalt salt. 18. A rubber composition according to any one of Embodiments 1 to 17, wherein the reinforcing filler comprises carbon black, silica, or a mixture of carbon black and silica. 19. A rubber composition according to any one of Embodiments 1 to 18, wherein the content of the reinforcing filler is between 20 and 200 phr. 20.1 A rubber composition according to any one of Embodiments 1 to 19, wherein the crosslinked peroxide compound based on one or more peroxide compounds accounts for 0.01 to 10 phr.

[0009] 21. A composition according to any one of Embodiments 1 to 20, which is free of sulfur molecules or contains less than 1 phr of them. 22. A composite material comprising at least a component having a metallic surface and a composition according to any one of Embodiments 1 to 21. 23. Composite materials according to embodiments 1 to 22, wherein the parts have a length equal to at least 1 millimeter. 24. A composite material according to any one of embodiments 22 and 23, wherein the component is a thread or a cable. 25. A composite material according to any one of embodiments 22 to 24, wherein the metallic surface of the part is made of a different material from the rest of the part. 26. A composite material according to any one of embodiments 22 to 25, wherein the metallic surface of the part comprises a metal selected from the group consisting of iron, copper, zinc, tin, aluminum, cobalt, nickel, and alloys containing at least one of these metals. 27. A composite material according to any one of embodiments 22 to 26, wherein the metal of the metallic surface is selected from iron, copper, tin, zinc, or an alloy containing at least one of these metals, and is preferably selected from the group consisting of brass, steel, zinc, and bronze.

[0010] 28. A finished product or a semi-finished product comprising a composition according to any one of Embodiments 1 to 21 or a composite material according to any one of Embodiments 22 to 27. 29. A pneumatic tire comprising a composition according to any one of Embodiments 1 to 21 or a composite material according to any one of Embodiments 22 to 27. A pneumatic tire comprising an inner layer containing a composition according to any one of Embodiments 1 to 21 or a composite material according to any one of Embodiments 22 to 27.

Mode for Carrying Out the Invention

[0011] Definition The expression "composition based on" should be understood to mean a composition comprising a mixture and / or product of in-situ reactions of the various constituents used, some of these (base) constituents being able to react at least partially with each other and / or being intended to react as such during the various manufacturing stages of the composition which modifies the composition as prepared at the start. Thus, the compositions used for the purposes of the present invention may be different in the uncrosslinked and crosslinked states. For the purposes of the present invention, the expression "parts by weight per 100 parts by weight of elastomer" (or phr) should be understood to mean parts by mass per 100 parts by mass of elastomer.

[0012] In the documents of the present invention, unless otherwise clearly indicated, all percentages (%) indicated are percentages by mass. Furthermore, any interval of values indicated by the expression "between a and b" represents a range of values extending from greater than a to less than b (i.e., the limit values a and b are excluded), while any interval of values indicated by the expression "a to b" means a range of values extending from a to b (i.e., including the exact limit values a and b). In the documents of the present invention, when an interval of values is indicated by the expression "a to b", the interval represented by the expression "between a and b" is also preferably indicated. The carbon-containing compounds mentioned in this description can be of fossil origin or of biobased origin. In the latter case, they can be derived partially or completely from biomass or obtained from renewable starting materials derived from biomass. This applies particularly to polymers, plasticizers, fillers and the like.

[0013] Elastomer The composition according to the present invention comprises at least one diene elastomer, preferably a highly unsaturated diene elastomer. It should be noted that the terms “dienelastomer” or “rubber” (the two terms are synonymous and interchangeable, as is well known) should be understood to mean an elastomer (i.e., a homopolymer or copolymer) obtained at least partially from a diene monomer (a monomer supporting two conjugated or unconjugated carbon-carbon double bonds). In this application, dienelastomers are, by definition, non-thermoplastic. Since diene elastomers have a negative Tg, i.e., a value below 0°C, they can be classified into two categories, as is well known: those called "essentially unsaturated" and those called "essentially saturated." "Essentially unsaturated" diene elastomers are understood to refer to diene elastomers obtained at least partially from conjugated diene monomers that have a content of more than 15% (mol%) of diene-derived units (conjugated dienes). In the classification of "essentially unsaturated" diene elastomers, "highly unsaturated" diene elastomers specifically refer to diene elastomers that have a content of more than 50% of diene-derived units (conjugated dienes).

[0014] In contrast, the term "essentially saturated" diene elastomer refers to elastomers that always have a low or very low content of diene-derived units, such as butyl rubber, or copolymers of dienes and EPDM-type α-olefins. Based on these definitions, the term "diene elastomer" that can be used in the compositions according to the present invention refers to any of the above classifications, as follows: (a) Any homopolymer of conjugated or unconjugated diene monomers containing 4 to 18 carbon atoms, (b) Any copolymer of a conjugated or unconjugated diene monomer containing 4 to 18 carbon atoms and at least one other monomer. Other monomers may be ethylene, olefins, or conjugated or unconjugated dienes. An example of such copolymer is ethylene-butadiene rubber (EBR).

[0015] Furthermore, the expression "diene elastomers that can be used in the compositions according to the present invention" is intended to mean the following: (a1) Any homopolymer obtained by polymerization of conjugated diene monomers containing 4 to 12 carbon atoms, (b1) Any copolymer obtained by copolymerizing one or more dienes conjugated to one or more dienes conjugated to one or more aromatic vinyl compounds containing 8 to 20 carbon atoms, (c1) A ternary copolymer obtained by copolymerizing ethylene and an α-olefin containing 3 to 6 carbon atoms with a non-conjugated diene monomer containing 6 to 12 carbon atoms, such as ethylene and propylene, and an elastomer obtained from the above type of non-conjugated diene monomer, particularly 1,4-hexadiene, ethylidene norbornene, or dicyclopentadiene. (d1) Isobutene and isoprene copolymers (diene butyl rubber) and halogenated versions thereof, in particular chlorinated or brominated versions of this type of copolymer.

[0016] 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C1-C5 alkyl)-1,3-butadiene, such as 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, or 2-methyl-3-isopropyl-1,3-butadiene, aryl-1,3-butadiene, 1,3-pentadiene, and 2,4-hexadiene are particularly suitable as conjugated dienes. Examples of aromatic vinyl compounds suitable for use include styrene, ortho-, meta-, or para-methylstyrene, commercial mixtures of "vinyltoluene," para-(tert-butyl)styrene, methoxystyrene, chlorostyrene, vinylmesitylene, divinylbenzene, and vinylnaphthalene. The copolymer may contain diene units between 99% and 20% by mass and aromatic vinyl units between 1% and 80% by mass. It is preferable to use at least one highly unsaturated diene elastomer, particularly one selected from the group consisting of natural rubber (NR), synthetic polyisoprene (IR), polybutadiene (BR), butadiene copolymer, isoprene copolymer, and mixtures thereof. Such copolymers are more preferably selected from the group consisting of butadiene / styrene copolymer (SBR), isoprene / butadiene copolymer (BIR), isoprene / styrene copolymer (SIR), isoprene / butadiene / styrene copolymer (SBIR), and mixtures thereof.

[0017] Preferably, the following are suitable: Polybutadiene, especially with a 1,2-unit content between 4% and 80% or a cis-1,4-unit content greater than 80%; polyisoprene, butadiene / styrene copolymer, especially with a styrene content between 5% and 50% by mass, more particularly between 20% and 40%, with a 1,2-bond content of the butadiene portion between 4% and 65%, and a trans-1,4-bond content between 20% and 80%; butadiene / isoprene copolymer, especially with an isoprene content between 5% and 90% by mass, and a glass transition temperature of -40°C to -80°C; or isoprene / styrene copolymer, especially with a styrene content between 5% and 50% by mass, T g It must be between -25°C and -50°C.

[0018] In the case of butadiene / styrene / isoprene copolymers, any butadiene / styrene / isoprene copolymer is particularly suitable, having a styrene content between 5% and 50% by mass, more particularly between 10% and 40% by mass; an isoprene content between 15% and 60% by mass, more particularly between 20% and 50% by mass; a butadiene content between 5% and 50% by mass, more particularly between 20% and 40% by mass; a 1,2-unit content of the butadiene moiety between 4% and 85%; a trans-1,4-unit content of the butadiene moiety between 6% and 80%; a 1,2- and 3,4-unit content of the isoprene moiety between 5% and 70%; a trans-1,4-unit content of the isoprene moiety between 10% and 50%; and more generally, a Tg between -20°C and 70°C. Elastomers can have any microstructure, which depends on the polymerization conditions used, particularly the presence or absence of modifiers and / or randomizers, and the amount of modifiers and / or randomizers used. Elastomers can be prepared, for example, in dispersions or solutions, and can be coupled and / or star-branched or functionalized using coupling agents and / or star-branching agents or functionalizing agents.

[0019] Examples of coupling of carbon black include functional groups containing C-Sn bonds or amination functional groups, such as benzophenone, and examples of coupling to inorganic reinforced fillers, such as silica, include silanol functional groups or polysiloxane functional groups having silanol termini (for example, as described in French Patent No. 2740778 or U.S. Patent No. 6013718), alkoxysilane groups (for example, as described in French Patent No. 2765882 or U.S. Patent No. 5977238), carboxyl groups (for example, as described in International Application No. 01 / 92402 or U.S. Patent No. 6815473, International Application No. 2004 / 096865 or U.S. Patent No. 2006 / 0089445), or polyether groups (for example, as described in European Patent No. 1127909 or U.S. Patent No. 6503973). Other examples of functionalized elastomers include epoxidized elastomers (e.g., SBR, BR, NR, or IR). The T of the above polymer g As is well known, it is measured, for example, by DSC (Differential Scanning Calorimetry) in accordance with ASTM standard D3418 (1999) unless otherwise specifically indicated in this application.

[0020] Crosslinked system Crosslinking generally improves the elastic properties of rubber compositions. Crosslinking systems are intended to react with elastomers in particular to bring about crosslinking in rubber compositions. Preferably, the rubber composition according to the present invention is free of sulfur molecules or contains less than 1 phr, preferably less than 0.5 phr, and more preferably less than 0.2 phr. Very preferably, the composition is free of any sulfur molecules as a crosslinking agent. The crosslinking system is based on at least one radical polymerization initiator. Radical polymerization initiators are free radical sources necessary for the polymerization of the rubber composition according to the present invention. These initiators are well known to those skilled in the art, and are described in particular, for example, International Application No. 2002 / 22688 and French Patent No. 2899808, as well as in the literature by Denisov et al. (Handbook of free radical initiators, John Wiley & Sons, 2003).

[0021] Preferably, according to the present invention, at least one radical polymerization initiator is selected from the group consisting of peroxides, azo compounds, redox (oxidation / reduction) systems and mixtures thereof, preferably from the group consisting of peroxides, azo compounds and mixtures thereof. More preferably, at least one radical polymerization initiator is a peroxide or a mixture of several peroxides. At least one radical polymerization initiator can be any peroxide known to those skilled in the art, as described, for example, in International Application No. 2017103387. Among the peroxides known to those skilled in the art, in the context of the present invention, it is preferable to use organic peroxides. The peroxide compound preferably accounts for 0.01 to 10 phr. The term "organic peroxide" is understood to mean an organic compound containing an -OO- group (two oxygen atoms linked by a single covalent bond), i.e., a carbon-containing compound.

[0022] During the crosslinking process, organic peroxides decompose at their unstable OO bonds, generating free radicals. These free radicals then enable the formation of crosslink bonds. According to one embodiment, the organic peroxide is selected from the group consisting of dialkyl peroxides, monoperoxy carbonates, diacyl peroxides, peroxyketals, and peroxyesters. Preferably, the dialkylperoxide is selected from the group consisting of dicumylperoxide, di(t-butyl)peroxide, t-butylcumylperoxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-amylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)hexa-3-yne, 2,5-dimethyl-2,5-di(t-amylperoxy)hexa-3-yne, α,α'-di[(t-butylperoxy)isopropyl]benzene, α,α'-di[(t-amylperoxy)isopropyl]benzene, di(t-amyl)peroxide, 1,3,5-tri[(t-butylperoxy)isopropyl]benzene, 1,3-dimethyl-3-(t-butylperoxy)butanol, and 1,3-dimethyl-3-(t-amylperoxy)butanol.

[0023] Dicumyl peroxide and mixtures of 1,3- and 1,4-isopropyl cumyl peroxide (e.g., sold by Arkema under the trademark Luperox® DC60) are also advantageous. Certain monoperoxycarbonates, such as OO-tert-butyl O-(2-ethylhexyl) monoperoxycarbonate, OO-tert-butyl O-isopropyl monoperoxycarbonate, and OO-tert-amyl O-(2-ethylhexyl) monoperoxycarbonate, can also be used. Among diacyl peroxides, the preferred peroxide is benzoyl peroxide.

[0024] Among peroxyketals, preferred peroxides are selected from the group consisting of 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl4,4-di(t-butylperoxy)valerate, ethyl3,3-di(t-butylperoxy)butyrate, 2,2-di(t-amylperoxy)propane, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxynonane (or methyl ethyl ketone peroxide cyclic trimer), 3,3,5,7,7-pentamethyl-1,2,4-trioxepane, n-butyl4,4-bis(t-amylperoxy)valerate, ethyl3,3-di(t-amylperoxy)butyrate, 1,1-di(t-butylperoxy)cyclohexane, 1,1-di(t-amylperoxy)cyclohexane, and mixtures thereof.

[0025] Preferably, the peroxyester is selected from the group consisting of tert-butylperoxybenzoate, tert-butylperoxy-2-ethylhexanoate, and tert-butylperoxy-3,5,5-trimethylhexanoate. Particularly preferred are organic peroxides such as dicumyl peroxide, aryl or diaryl peroxide, diacetyl peroxide, benzoyl peroxide, dibenzoyl peroxide, di(tert-butyl) peroxide, tert-butylcumyl peroxide, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, n-butyl 4,4'-di(tert-butylperoxy)valerate, O,O-(t-butyl)O-(2-ethylhexyl) monoperoxycarbonate, tert-butylperoxyisopropyl carbonate, tert-butylperoxybenzoate, tert-butylperoxy-3,5, From the group consisting of 5-trimethylhexanoate, 1,3(4)-bis(tert-butylperoxyisopropyl)benzene and mixtures thereof, more preferably selected from the group consisting of dicumyl peroxide, n-butyl 4,4'-di(tert-butylperoxy)valerate, O,O-(t-butyl)O-(2-ethylhexyl)monoperoxycarbonate, tert-butylperoxyisopropyl carbonate, tert-butylperoxybenzoate, tert-butylperoxy-3,5,5-trimethylhexanoate, 1,3(4)-bis(tert-butylperoxyisopropyl)benzene and mixtures thereof.

[0026] In a preferred embodiment, the rubber composition according to the present invention does not contain any crosslinking systems other than those described above, based on one or more peroxide compounds. The composition preferably does not contain any vulcanization accelerators or activators known to those skilled in the art, or contains them in amounts of less than 1 phr, preferably less than 0.5 phr, and more preferably less than 0.2 phr. Reinforced filler Any type of reinforcing filler known for its ability to strengthen rubber compositions that can be used in the manufacture of pneumatic tires, such as organic fillers, such as carbon black; inorganic reinforcing fillers, such as silica; or blends of these two types of fillers, particularly a blend of carbon black and silica, may be used. All carbon blacks, particularly HAF, ISAF, or SAF type blacks ("tire-grade" blacks) conventionally used in pneumatic tires, are suitable as carbon blacks. Among the latter types, particularly, are the 100, 200, or 300 series (ASTM grade) reinforced carbon blacks, such as N115, N134, N234, N326, N330, N339, N347, or N375 blacks, or, depending on the target application, higher-grade series blacks (e.g., N660, N683, or N772). Carbon black may already be incorporated into isoprene elastomers, for example, in the form of a masterbatch (see, for example, International Application No. 97 / 36724 or International Application No. 99 / 16600).

[0027] Examples of organic fillers other than carbon black include, for example, the functionalized polyvinyl organic fillers described in International Applications Nos. 2006 / 069792, 2006 / 069793, 2008 / 003434, and 2008 / 003435. In this application, the term “inorganic reinforcing filler” should be understood, by definition, to mean any inorganic or mineral filler (regardless of its color and origin, natural or synthetic) also known as “white filler,” “clear filler,” or even “non-black filler,” in contrast to carbon black, which can, by itself alone, reinforcing rubber compositions intended for the manufacture of pneumatic tires, without the use of any means other than intermediate coupling agents, in other words, can replace conventional tire-grade carbon black in its reinforcing role, and such fillers are generally characterized by the presence of hydroxyl (-OH) groups on their surface, as is well known.

[0028] The physical state in which the inorganic reinforced filler is provided, whether in the form of powder, microbeads, granules, beads, or any other suitable high-densification form, is not important. Naturally, “inorganic reinforced filler” is understood to also mean the various inorganic reinforced fillers described below herein, for example, mixtures of highly dispersible silica and / or alumina fillers. Silica-type mineral fillers, especially silica (SiO2), or alumina-type mineral fillers, especially alumina (Al2O3), are particularly suitable as inorganic strengthening fillers. Any strengthening silica known to those skilled in the art, especially both 450m, can be used. 2 Less than 30-400mg / g 2 Any precipitated or fumed silica exhibiting a BET surface area and CTAB specific surface area of ​​1 / g may be used. Examples of highly dispersible precipitated silica ("HDS") include Ultrasil 7000 and Ultrasil 7005 silica from Degussa, Zeosil 1165MP, 1135MP and 1115MP silica from Rhodia, Hi-Sil EZ150G silica from PPG, Zeopol 8715, 8745 and 8755 silica from Huber, or silicas with a high specific surface area as described in International Application No. 03 / 16837.

[0029] The inorganic reinforced filler used, especially if silica, is preferably 45-400m 2 Between / g, 60-300m is preferred. 2 It has a BET surface area between / g. Preferably, the total content of reinforcing fillers (carbon black and / or inorganic reinforcing fillers, e.g., silica) is between 20 and 200 phr, more preferably between 30 and 150 phr. The optimal total content, as is well known, varies depending on the specific application being targeted. For example, the expected level of reinforcement for bicycle tires is naturally below the level required for tires that can travel at high speeds for extended periods, such as motorcycle tires, passenger vehicle tires, or work vehicle tires, such as heavy-duty vehicle tires. According to preferred embodiments of the present invention, an organic filler, particularly a reinforcing filler containing carbon black, may also contain silica, in a content between 30 and 150 phr, more preferably between 50 and 120 phr, wherein the silica, if present, is used in a content of less than 20 phr, more preferably less than 10 phr (e.g., between 0.1 and 10 phr).

[0030] Alternatively, according to another preferred embodiment of the present invention, an inorganic filler, particularly silica, may be used in a concentration between 30 and 150 phr, more preferably between 50 and 120 phr, and may also contain carbon black, where the carbon black, if present, is used in a concentration of less than 20 phr, more preferably less than 10 phr (e.g., between 0.1 and 10 phr). To couple an inorganic reinforced filler to an elastomer, as is well known, at least a bifunctional coupling agent (or binder), particularly a bifunctional organosilane or polyorganosiloxane, can be used, intended to provide a satisfactory chemical and / or physical bond between the inorganic filler (the surface of its particles) and the elastomer.

[0031] In particular, silane polysulfides referred to as "symmetrical" or "asymmetrical" may be used depending on their specific structure, as described, for example, in International Patent Application No. 03 / 002648 (or U.S. Patent Application No. 2005 / 016651) and International Patent Application No. 03 / 002649 (or U.S. Patent Application No. 2005 / 016650). More specifically, examples of silane polysulfides include bis((C1-C4)alkoxyl(C1-C4)alkylsilyl(C1-C4)alkyl) polysulfides (especially disulfides, trisulfides, or tetrasulfides), such as bis(3-trimethoxysilylpropyl) or bis(3-triethoxysilylpropyl) polysulfide. Among these compounds, bis(3-triethoxysilylpropyl)tetrasulfide of formula [(C2H5O)3Si(CH2)3S2]2, abbreviated as TESPT, or bis(triethoxysilylpropyl)disulfide of formula [(C2H5O)3Si(CH2)3S]2, abbreviated as TESPD, are particularly used. Preferred examples include bis(mono(C1-C4)alkoxyldi(C1-C4)alkylsilylpropyl) polysulfides (especially disulfides, trisulfides, or tetrasulfides), and more particularly, bis(monoethoxydimethylsilylpropyl)tetrasulfide, as described in, for example, U.S. Patent Application No. 2004 / 132880.

[0032] Other coupling agents besides alkoxysilane polysulfides include, in particular, bifunctional POS (polyorganosiloxane), or hydroxysilane polysulfides described in, for example, International Applications No. 02 / 30939 and 02 / 31041, or silanes or POS supporting azodicarbonyl functional groups described in, for example, International Applications No. 2006 / 125532, 2006 / 125533 and 2006 / 125534. The content of the coupling agent in the rubber composition according to the present invention is preferably between 4 and 12 phr, and more preferably between 4 and 8 phr. In another embodiment, the rubber composition according to the present invention contains no coupling agent whatsoever. Those skilled in the art will understand that other types of reinforcing fillers, particularly organic ones, may be used as equivalent fillers to the inorganic reinforcing fillers described in the section of the present invention, provided that these reinforcing fillers are coated with an inorganic layer, such as silica, or have functional sites, particularly hydroxyl sites, on their surface, which enable the establishment of bonds between the filler and the elastomer, in the presence or absence of a coating agent or coupling agent.

[0033] Phenolic compounds The composition according to the present invention comprises at least one phenol compound having a molar mass equal to a maximum of 1000 g / mol, wherein the hydrocarbon group is interrupted and / or substituted by an oxygen atom, and may be interrupted and / or substituted by one or more heteroatoms. The term "heteroatom" is intended to mean at least a monovalent atom distinct from hydrogen and carbon atoms, preferably selected from nitrogen and oxygen. Preferably, the phenol group of the phenol compound is substituted with at least two hydrocarbon groups, which may be interrupted and / or substituted by one or more heteroatoms, at least one of the hydrocarbon groups being interrupted and / or substituted by an oxygen atom, and the two hydrocarbon groups together with the carbon atoms of the aromatic ring of the phenol group to which they are bonded can form a ring, which may be interrupted and / or substituted by one or more heteroatoms. In preference, phenol compounds are those of general formula (I)

[0034] [ka] [In the formula, - G1 represents a hydroxyl, carboxyl, or alkoxy group, or a hydrogen atom. - G2 represents a hydroxyl or carboxyl group, or a hydrogen atom. - G3 represents a hydroxyl, carboxyl, hydrogencarbonyl, carboxyalkyl, carboxyalkylene, alkoxy, amino, aminoalkyl, amide or vinyl group, or a hydrogen atom corresponds to At least one of the substituents G1 to G3 contains an oxygen atom, and the molar mass of the phenolic compound is at most equal to 1000 g / mol. The term "carboxyl group" or "carboxylic acid functional group" means a group of the formula -COOH in which a carbon atom is linked to an oxygen atom via a double bond and to a hydroxy group -OH via a single bond. The term "carboxyalkyl group" means a radical of the formula -C n H 2n -COOH, where n is an integer preferably in the range from 1 to 15, more preferably from 1 to 10, very preferably from 1 to 5, and preferably from 1 to 3.

[0035] The term "alkoxy group" means a group of the formula -OC n H 2n+1 where n represents an integer in the range from 1 to 10, very preferably from 1 to 5, and preferably from 1 to 3. The term "hydrogencarbonyl group" means a group of the formula -CHO in which a carbon atom is linked to an oxygen atom via a double bond and to a hydrogen atom via a single bond. The term "amino group" means a group of the formula -NH2. The term "aminoalkyl group" means a radical of the formula -C n H 2n -NH2, where n is an integer preferably in the range from 1 to 15, more preferably from 1 to 10, very preferably from 1 to 5, and preferably from 1 to 3. Preferably, the phenolic compound is substituted with at least two hydroxy groups. Preferably, G1, G2 and G3 independently represent a hydroxyl or carboxyl group, or a hydrogen atom, and more preferably independently represent a hydroxyl or carboxyl group.

[0036] Advantageously, the phenol compound is substituted with at least one carboxyl group. Advantageously, the phenol compound is substituted at least at the para position relative to the hydroxyl group. The term “substituted at the para position” means, as is known to those skilled in the art, that the aromatic nucleus of the phenol compound is substituted at position 4, the hydroxyl group is considered to be at position 1, and positions 1 through 6 correspond to the carbon atoms constituting the aromatic nucleus. Surprisingly, the applicant has found that the adhesive properties of the compositions according to the present invention are particularly improved when the phenol compound is substituted at least at the para position relative to the hydroxyl group. The adhesive properties are particularly advantageous when the phenol compound is substituted with a carboxyl group at the para position relative to the hydroxyl group. Regardless of the preferred embodiment, the molar mass of the phenol compound is at most 1000 g / mol, preferably less than 800 g / mol, preferredly less than 600 g / mol, very preferably less than 400 g / mol, very preferably less than 220 g / mol, very preferably less than 200 g / mol, or even equal to 180 g / mol. Among the phenolic compounds used as necessary for the present invention, examples include 1,4-dihydroxy-2-naphthoic acid, curcumin, resveratrol, daidzein, genistein, apigenin, umbelliferone, l-tyrosine, guaiacol, 2-hydroxy-4-methoxybenzaldehyde, isovanillin, salicylic acid, acetaminophen, 4-hydroxybenzaldehyde, caffeic acid, 5-aminosalicylic acid, 3,4-dihydroxybenzaldehyde, 2,5-dihydroxyterephthalic acid, vanillin, 2,5-dihydroxybenzoic acid, gallic acid, protocatechuic acid, 4-hydroxyisophthalic acid, 2,3,4-trihydroxybenzoic acid, 3-O-methylgallic acid, 4,5-dihydroxyphthalic acid, 2,4,5-trihydroxybenzoic acid, and mixtures thereof.

[0037] Among these compounds, particularly preferred are acetaminophen, 4-hydroxybenzaldehyde, caffeic acid, 5-aminosalicylic acid, 3,4-dihydroxybenzaldehyde, 2,5-dihydroxyterephthalic acid, vanillin, 2,5-dihydroxybenzoic acid, gallic acid, protocatechuic acid, 4-hydroxyisophthalic acid, 2,3,4-trihydroxybenzoic acid, 3-O-methylgallic acid, 4,5-dihydroxyphthalic acid, 2,4,5-trihydroxybenzoic acid, and mixtures thereof. Preferably, the compound is selected from caffeic acid, gallic acid, protocatechuic acid, 4-hydroxyisophthalic acid, 2,3,4-trihydroxybenzoic acid, 3-O-methylgallic acid, 4,5-dihydroxyphthalic acid, 2,4,5-trihydroxybenzoic acid, and mixtures thereof, with caffeic acid, gallic acid, and protocatechuic acid being preferred. Very preferably, the phenol compound is gallic acid.

[0038] The rubber composition according to the present invention preferably contains a phenol compound in an amount of 0.1 to 25 phr, and more preferably 2 to 15 phr. Below 0.1 phr, the phenol compound has no notable effect on the adhesive properties of the rubber composition according to the present invention. Above 25 phr, no further significant benefits are observed. Compounds of the monosaccharide family The rubber composition according to the present invention comprises at least one compound from a monosaccharide family selected from aldoses and ketoses. Monosaccharides are carbohydrate monomers. Aldoses are monosaccharides whose carbonyl functional group is an aldehyde. Ketoses are monosaccharides whose carbonyl functional group is a ketone. It has been discovered that in rubber compositions crosslinked with a peroxide-based crosslinking system, a combination of specific phenolic compounds and monosaccharide family compounds can provide excellent adhesion to metal parts.

[0039] Preferably, the monosaccharide family compound is selected from triose, tetrose, pentose, and hexose, with a preference for pentose and hexose. Preferably, the monosaccharide family compound is selected from fructose, psicose, sorbose, tagatose, allose, altrose, glucose, mannose, growth, idose, galactose, and talose, with a preference for fructose, glucose, mannose, and galactose, and a very preference for fructose and glucose. Preferably, the content of monosaccharide family compounds is between 0.1 and 15 phr, more preferably between 0.1 and 10 phr. Various additives The rubber compositions according to the present invention may also include, in whole or in part, common additives known to those skilled in the art and generally used in rubber compositions for pneumatic tires, particularly in inner layer compositions as further defined herein, such as plasticizers (plasticizing oils and / or plasticizing resins), reinforcing or non-reinforcing fillers other than those described herein, pigments, protective agents, such as anti-ozone waxes, chemical anti-ozone or antioxidant agents, fatigue inhibitors, or reinforcing resins (such as those described in International Application No. 02 / 10269).

[0040] These compositions may also contain, in addition to coupling agents, coupling activators, agents for coating inorganic fillers, or, more generally, processing aids that can improve the ability to be processed in the raw state by improving the dispersion of fillers in the rubber matrix and by reducing the viscosity of the composition, as is well known. These agents are, for example, hydrolyzable silanes, such as alkylalkoxysilanes (e.g., octyltriethoxysilane or octeosilane), polyols, polyethers, primary, secondary or tertiary amines, or hydroxylated or hydrolyzable polyorganosiloxanes.

[0041] Surprisingly, the excellent adhesion of the compositions according to the present invention to reinforced cables is achieved without the need to use cobalt salts. Therefore, the compositions according to the present invention either do not contain cobalt salts, which are known to those skilled in the art, for their known effect of improving adhesion, or contain them in amounts of less than 1 phr, preferably less than 0.5 phr, more preferably less than 0.2 phr, and very preferably less than 0.1 phr. Preparation of rubber composition The rubber composition according to the present invention is manufactured using a suitable mixer and preparation steps well known to those skilled in the art. - A thermomechanical work or mixing stage may be carried out in a single thermomechanical step while all essential components, in particular the elastomer matrix, phenolic compounds, fillers, and any various other additives are introduced into a suitable mixer, e.g., a standard internal mixer (e.g., a "Banbury" type). The incorporation of fillers into the elastomer may be carried out in one or more stages while thermomechanically mixing. If the fillers, in particular carbon black, are already incorporated into the elastomer, either completely or partially, in the form of a masterbatch, as described, for example, in International Application No. 97 / 36724 or International Application No. 99 / 16600, then the fillers are the masterbatch that is directly mixed, and where appropriate, other elastomers or fillers that are not in masterbatch form are present in the composition, and any various other additives are incorporated.

[0042] Thermomechanical mixing is generally carried out at a high temperature between 110°C and 200°C, preferably up to a maximum temperature between 130°C and 185°C, for a period of 2 to 10 minutes. - Subsequently, the second stage of mechanical work can be carried out in an external mixer, such as an open mill, after the mixture obtained during the first stage has been cooled to a lower temperature, typically below 120°C, for example, between 40°C and 100°C. When crosslinking is performed, any crosslinking system is added during the first or second stage in accordance with the knowledge of those skilled in the art. Peroxide-based crosslinking systems are typically added during the second stage. The resulting final composition is then calendered, for example, in the form of a sheet or plate, particularly for laboratory characterization, or extruded in the form of a rubber semi-finished product (or a profiled element).

[0043] The composition may be in a raw state (before crosslinking) or a cured state (after crosslinking), or it may be a semi-finished product that can be used in pneumatic tires. Curing can generally be carried out at a temperature between 130°C and 200°C under pressure for a sufficient time, for example, 5 to 90 minutes, which can vary as a function of the curing temperature of the composition of particular consideration, the crosslinking system employed, the crosslinking dynamics, or the size of the pneumatic tire, in a manner known to those skilled in the art. composite material The present invention also relates to a component having a metallic surface and a composite material based at least on a rubber composition according to the present invention. The expression "composite material based at least on the parts and compositions according to the present invention" should be understood to mean a composite material comprising parts and compositions, wherein the compositions were able to react with the surface of the parts during various stages of the manufacturing of the composite material, particularly during the crosslinking of the compositions, or during the manufacturing of the composite material before the compositions are crosslinked.

[0044] The aforementioned component may be entirely or partially metallic. The metallic surface of the component is intended to constitute at least a portion, preferably all, of the surface of the component and to be in contact with the composition according to the present invention. The composition according to the present invention coats at least a portion, and preferably all, of the component. The component is advantageously partially or completely metallic, and the metallic portion includes at least a metallic surface. Preferably, the component is entirely made of metal. According to a first modification of the present invention, the metallic surface of a part is made of a different material from the rest of the part. In other words, the part is made of a material that is at least partially, preferably entirely, coated with a metallic layer that forms a metallic surface. The material that is at least partially, preferably entirely, coated with a metallic surface is metallic or non-metallic, and preferably metallic in nature.

[0045] According to a second modification of the present invention, the parts are made from the same material, in this case the parts are made from the same metal as the metal of the metallic surface. According to one embodiment of the present invention, the metallic surface comprises a metal selected from the group consisting of iron, copper, zinc, tin, aluminum, cobalt, nickel, and alloys containing at least one of these metals. The alloy may be, for example, a binary or ternary alloy, such as steel, bronze, and brass. Preferably, the metal of the metallic surface is iron, copper, tin, zinc, or an alloy containing at least one of these metals. More preferably, the metal of the metallic surface is steel, brass (Cu-Zn alloy), zinc, or bronze (Cu-Sn alloy), even more preferably brass or zinc, and very preferably brass. In this application, the expression "the metal of the metallic surface is the metal shown below" means that the metallic surface is made from the metal shown below. For example, the expression "the metal of the metallic surface is brass" written earlier means that the metallic surface is made from brass. Certain metals undergo oxidation when they come into contact with ambient air, so metals can be partially oxidized, with the exception of stainless steel. If the metallic surface is made of steel, the steel is preferably carbon steel or stainless steel. If the steel is carbon steel, its carbon content is preferably between 0.01% and 1.2%, or between 0.05% and 1.2%, or between 0.2% and 1.2%, particularly between 0.4% and 1.1%. If the steel is stainless steel, it preferably contains at least 11% chromium and at least 50% iron.

[0046] The components can be of any shape. Preferably, the components are provided in the form of threads or cables. According to certain embodiments of the present invention, the component has a length equal to at least 1 millimeter. Length refers to the longest dimension of the component. Examples of components having a length equal to at least 1 millimeter include pneumatic tires for vehicles, and reinforcing elements used in thread-like elements (monofilament or cable) and non-thread-like elements. According to a particularly preferred embodiment of the present invention, the composite material is a reinforced structure in which components constitute reinforcing elements and the composition according to the present invention coats the reinforcing elements. In particular, according to a preferred embodiment, the composite material is a reinforced product comprising reinforcing elements and calendered rubber in which the reinforcing elements are embedded, each reinforcing element comprising a component already defined according to any one embodiment of the present invention and calendered rubber comprising a rubber composition according to the present invention. According to this embodiment, the reinforcing elements are generally arranged adjacent to each other along the central direction. Thus, in applications envisioned for pneumatic tires, the composite material can constitute a reinforcing material for pneumatic tires.

[0047] The composite material according to the present invention may be in a green state (before crosslinking of the rubber composition) or a cured state (after crosslinking of the rubber composition). The composite material hardens after the part is brought into contact with the rubber composition according to the present invention. Composite materials can be manufactured by a process that includes the following steps: - A step of preparing two layers of the composition according to the present invention, - By placing the component between the two layers, the step of sandwiching the component between the two layers, - If appropriate, a step to cure the composite material. Alternatively, the composite material may be manufactured by placing a component on top of a layer, which then folds itself to cover the component so that it is sandwiched over its entire length or part of its length.

[0048] The layers can be created by calendering. During the curing of the composite material, the rubber composition is crosslinked. When composite materials are intended to be used as reinforcements in pneumatic tires, the curing of the composite material generally occurs during the curing of the pneumatic tire casing. Finished product or semi-finished product The subject matter of the present invention is also finished or semi-finished products comprising compositions or composite materials according to the present invention. The term "finished product" means an article that can be used as is, for example, a conveyor belt. The term "semi-finished product" means an article intended to be incorporated into a final product, for example, a reinforced ply for a pneumatic tire.

[0049] pneumatic tires Another subject of the present invention, a pneumatic tire, has the essential feature of comprising a composition or composite material according to the present invention. The pneumatic tire may be in a raw state (before crosslinking of the rubber composition) or a cured state (after crosslinking of the rubber composition). Generally, during the manufacture of a pneumatic tire, the composition or composite material is placed in the structure of the pneumatic tire in a raw state (i.e., before crosslinking of the rubber composition) before the step of curing the pneumatic tire. The present invention relates in particular to a pneumatic tire intended to be installed on passenger vehicles, SUVs (sport utility vehicles), or two-wheeled vehicles (especially motorcycles), or aircraft, or vans, heavy vehicles, i.e., subway trains, buses, heavy road transport vehicles (cargo trucks, tow trucks, trailers), or off-road vehicles, such as agricultural vehicles or construction vehicles, selected from industrial vehicles.

[0050] In the case of pneumatic tires, it is possible to define the following three types of areas: • The radially outer region in contact with the ambient air, this region essentially consists of the tread and outer wall of the pneumatic tire. The outer wall is an elastomer layer located outside the carcass reinforcement relative to the internal cavity of the pneumatic tire, between the crown and the bead, so as to completely or partially cover the region of the carcass reinforcement extending from the crown to the bead. • The radially inner region in contact with the expanding gas, this region generally consists of an airtight layer relative to the expanding gas, which is sometimes known as the inner airtight layer or inner liner. • The inner region of a pneumatic tire, i.e., the region between the outer and inner regions. This region includes layers or plies referred to here as the inner layers of the pneumatic tire. These are, for example, carcass plies, tread sublayers, pneumatic tire belt plies, or any other layers that do not come into contact with the ambient air or the inflation gas of the pneumatic tire. The compositions defined in this description are particularly well-suited for the inner layer of pneumatic tires. Accordingly, the present invention also relates to a pneumatic tire comprising an inner layer containing a composition or composite material according to the present invention. According to the present invention, the inner layer may be selected from the group consisting of carcass plies, crown plies, bead wire fillings, crown feet, decoupling layers, tread underlayers, and combinations thereof. Preferably, the inner layer is selected from the group consisting of carcass plies, crown plies, bead wire fillings, crown feet, decoupling layers, and combinations thereof. [Examples]

[0051] The following procedure is used to prepare different rubber compositions: The diene elastomer and then all other components of the mixture are sequentially introduced into an internal mixer (final filling density: approximately 70 vol%), with an initial container temperature of approximately 60°C. Next, a thermomechanical operation is performed in one step until the maximum "decay" temperature reaches 150°C. The resulting mixture is then collected and cooled to 30°C in an external mixer (homofinisher) to mix everything together. The prepared rubber compositions are shown in Table 1.

[0052] [Table 1] All compositions are indicated by phr. (1) Natural rubber (2) N347 (3) Supplied by Sigma-Aldrich It should be noted that composition "T1" does not contain any specific phenol compounds or compounds from the monosaccharide family. Composition "T2" contains only specific phenol compounds, while composition "T3" contains only compounds from the monosaccharide family, in this case aldoses having six carbon atoms. Composition "C1" contains both specific phenol compounds and compounds from the ketose family, and composition "C2" contains both specific phenol compounds and compounds from the aldose family.

[0053] The quality of the bond between the rubber composition and the component is determined by a test based on ASTM standard D2229, which measures the force required to pull out individual thread sections with metallic surfaces from the crosslinked rubber composition. For this purpose, the composite material is prepared in the form of test specimens containing, on the one hand, a 2.30NF22 type metal reinforcer, which is conventionally used in the field of pneumatic tires as a component with a metallic surface, and on the other hand, an elastomer mixture containing the crosslinked rubber composition. Preparation of test specimens The following protocol is used to prepare composite materials in the form of test specimens using a rubber composition. A rubber block is produced consisting of two plates stacked on top of each other before curing. The two plates of the block are made of the same rubber composition. During the formation of the block, the reinforcing agent is trapped equidistant between the two raw plates, while leaving an end of the reinforcing agent, long enough for subsequent tensile testing, protruding onto one of the sides of these plates. The block containing the reinforcing agent is then placed in a mold adapted to the target test conditions, to the discretion of those skilled in the art. For example, in the present invention, the block is cured at 170°C under a pressure of 5.5 tons for a time ranging from 25 to 90 minutes, according to the composition.

[0054] The reinforcement is a 2.30NF22 cable consisting of 0.6 mm steel threads coated with brass. The thickness of the brass coating is 200 nm to 1 μm. A test specimen prepared using the composition according to the present invention corresponds to a composite material according to the present invention. Adhesion test Once curing is complete, the test specimens, consisting of the crosslinked blocks and reinforcing agent, are placed on the jaws of a tensile testing machine, which has been adapted to allow each section to be tested separately at a given speed and temperature (for example, 100 mm / min and ambient temperature in the present invention). The level of adhesion is characterized by measuring the "peel" force that separates the reinforcing agent from each section of the test specimen. The results are expressed with a base of 100 against a control test specimen containing a reinforcing agent with the same properties as that of the tested specimen and containing the rubber composition "T1" shown in Table 1. A value exceeding the value set to 100 for the control specimen by discretion indicates an improved result, i.e., a peeling force greater than that of the control specimen whose value was set to 100 by discretion.

[0055] [Table 2] Table 2 shows the results of adhesion tests conducted on control specimens and specimens according to the present invention. It should be noted that a comparison of T2 and T1 demonstrates that using gallic acid alone can improve the adhesion of materials to the reinforcing agent. The combination of a specific phenolic compound in the examples, in this case gallic acid, with a monosaccharide family compound such as glucose or fructose, makes it possible to significantly improve the adhesion of the rubber composition to the reinforcing agent.

Claims

1. A rubber composition comprising at least one diene elastomer, a reinforcing filler, a crosslinking agent based on at least one radical polymerization initiator, and at least one phenol compound having a molar mass equal to 1000 g / mol, wherein the phenol compound is gallic acid, and the hydrocarbon group is interrupted and / or substituted by an oxygen atom, which may be interrupted and / or substituted by one or more heteroatoms, and the rubber composition further comprises at least one compound of a monosaccharide family selected from aldoses and ketoses.

2. The composition according to claim 1, wherein the content of the phenol compound is between 0.1 and 25 phr.

3. The composition according to claim 1 or 2, wherein the monosaccharide family compound is selected from fructose, psicose, sorbose, tagatose, allose, altrose, glucose, mannose, growth, idose, galactose, and talose.

4. The composition according to any one of claims 1 to 3, wherein the content of monosaccharide family compounds is between 0.1 and 15 phr.

5. A component having at least a metallic surface and a composite material based on the composition described in any one of claims 1 to 4.

6. A finished product or a semi-finished product comprising the composition according to any one of claims 1 to 4 or the composite material according to claim 5.

7. A pneumatic tire comprising the composition according to any one of claims 1 to 4 or the composite material according to claim 5.

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