REINFORCED RUBBER COMPOSITION

Description

[0001] The present invention relates to rubber compositions reinforced with a reinforcing filler, in particular intended for the manufacture of tires or semi-finished products for tires, in particular the treads of these tires.

[0002] The rubber compositions used in the manufacture of tires usually comprise natural or synthetic rubbers which are diene elastomers comprising carbon-carbon double bonds, also called unsaturations, in their main chain. The presence of these double bonds makes these elastomers sensitive in particular to thermo-oxidation, such as for example heating which occurs during the use of the tire. This heating can lead to modifications of the properties of the rubber compositions and in particular to changing the mechanical properties of these compositions and the behavior of the semi-finished articles containing them.

[0003] Furthermore, it is a constant objective for tire manufacturers to find solutions to improve the endurance of tires.

[0004] One solution being considered would be to partially replace the elastomers traditionally used with elastomers containing few or no double bonds in their main chain, such as, for example, ethylene and vinyl acetate copolymers (EVA copolymers).

[0005] EVA copolymers are thermoplastic copolymers with elastomeric properties. They are mainly used in the packaging, food and adhesive industries.

[0006] In the field of tires, document EP1085049A2 describes the use of EVA copolymers in a minority quantity compared to the usual diene elastomers to improve the grip of treads for winter tires.

[0007] Indeed, it is known from document WO2014 / 042943A1 that the presence of reinforcing fillers, such as silica or carbon black, have a detrimental effect on the stability of EVA copolymers at high temperature (use temperature).

[0008] However, the presence of reinforcing fillers is essential in a rubber composition to obtain tires with good wear resistance. To solve the problem linked to the presence of fillers in a composition comprising EVA copolymers, document WO2014 / 042943A1 teaches the addition of a polyamide to the composition, at a rate ranging from 5 to 60% by weight. These compositions have the disadvantage of being too rigid and are not suitable for pneumatic use.

[0009] Furthermore, document WO 2016 / 005536 discloses expanded compositions comprising a polymer P, an acrylate A, a peroxide, which can be immobilized on a calcium carbonate and silica support, and a swelling agent. The support does not act as a reinforcing filler. ante, satisfactory properties cannot be obtained for pneumatic application.

[0010] There is therefore still a need to produce rubber compositions or mixtures having stable properties, such as rigidity for example, despite the thermal changes (variations) undergone by these compositions or mixtures during their use.

[0011] The inventors have discovered, surprisingly and contrary to what was known, that EVA copolymers could totally or partially replace the usual diene elastomers in tire rubber compositions. Indeed, a specific combination of a copolymer based on at least one ethylene monomer and at least one vinyl acetate monomer and a copolymer based on at least one alpha-olefin monomer and at least one functionalized monomer, in the presence of inorganic reinforcing fillers, made it possible to obtain compositions having a rigidity that changes little as a function of temperature while maintaining resistance to large deformations and good reinforcement.

[0012] Thus, the invention relates to a rubber composition based on at least: a copolymer A with a content greater than or equal to 50 phr, said copolymer A being a copolymer based on at least one ethylene monomer and at least one vinyl acetate monomer, an inorganic reinforcing filler which is characterized by the presence of hydroxyl groups on its surface, the content of inorganic reinforcing filler being greater than or equal to 20 phr, as a coupling agent between said copolymer A and said inorganic reinforcing filler a copolymer B different from said copolymer A, said copolymer B being a copolymer based on at least one alpha-olefin monomer and at least one functional monomer Y, the functional monomer Y being chosen from monomers carrying an epoxide function and monomers carrying a carboxylic acid function, the molar percentage of said functional monomer Y in said copolymer B is greater than or equal to 0.5%, and a crosslinking system with peroxides.

[0013] Preferably, in the composition as defined above, the molar rate of ethylene monomer in copolymer A is greater than or equal to 51%, preferably greater than or equal to 55%.

[0014] Preferably, in the composition as defined above, the molar rate of ethylene monomer in copolymer A ranges from 57% to 90%.

[0015] Preferably, in the composition as defined above, the molar percentage of the functional monomer Y in the copolymer B is greater than or equal to 0.7%.

[0016] Preferably, in the composition as defined above, the molar percentage of the functional monomer Y in the copolymer B ranges from 0.7% to 10%.

[0017] Preferably, in the composition as defined above, the functional monomer Y of the copolymer B is a monomer carrying an epoxide function, said functional monomer Y being chosen from aliphatic glycidyl esters, aliphatic glycidyl ethers, alicyclic glycidyl esters and alicyclic glycidyl ethers.

[0018] Preferably, in the composition as defined above, the functional monomer Y of the copolymer B is chosen from glycidyl methacrylate and glycidyl acrylate.

[0019] Preferably, in the composition as defined above, the alpha-olefin monomer of copolymer B is ethylene.

[0020] Preferably, in the composition as defined above, the copolymer B is chosen from ethylene / glycidyl methacrylate copolymers, ethylene / glycidyl acrylate copolymers, ethylene / C1-C10 alkyl acrylate / glycidyl methacrylate copolymers, ethylene / C1-C10 alkyl acrylate / glycidyl acrylate copolymers, ethylene / vinyl acetate / glycidyl acrylate copolymers, ethylene / vinyl acetate / glycidyl methacrylate copolymers, ethylene / C1-C10 alkyl methacrylate / glycidyl methacrylate copolymers and ethylene / C1-C10 alkyl methacrylate / glycidyl acrylate copolymers.

[0021] Preferably, in the composition as defined above, copolymer A consists of ethylene monomer and vinyl acetate monomer.

[0022] Preferably, the composition as defined above comprises a mixture of copolymers A which are different from each other.

[0023] Preferably, in the composition as defined above, the content of copolymer A or the mixture of copolymers A is equal to 100 pce.

[0024] Preferably, the composition as defined above further comprises a polymer C, different from copolymer A and copolymer B.

[0025] Preferably, in the composition as defined above, the polymer C is a diene elastomer and has a molar content of diene unit of less than 15%.

[0026] Preferably, in the composition as defined above, the rate of inorganic reinforcing filler ranges from 30 to 80 pce.

[0027] Preferably, in the composition as defined above, the content of copolymer B ranges from 1 to 25 pce.

[0028] Preferably, in the composition as defined above, the content of copolymer B is greater than or equal to 5% by weight relative to the weight of the inorganic reinforcing filler.

[0029] Preferably, in the composition as defined above, the content of copolymer B ranges from 5% to 30% by weight relative to the weight of the inorganic reinforcing filler.

[0030] Preferably, in the composition as defined above, the inorganic reinforcing filler comprises silica.

[0031] The invention also relates to a semi-finished article for a tire comprising at least one composition as described above.

[0032] The invention also relates to a tire comprising at least one composition as defined above or comprising at least one semi-finished article for a tire as described above.

[0033] The invention also relates to the use of the composition as defined above in foams or foam articles, or as impact additives for thermoplastic materials, or as additives for bitumen, or even in hot-melt structural adhesives or in the field of cabling. I. MEASURES AND TESTS USED I-1) Tensile tests

[0034] These tests determine the yield stresses and the properties at break. Unless otherwise indicated, they are carried out in accordance with the French standard NF T 46-002 of September 1988. The nominal secant moduli (or apparent stresses, in MPa) are measured at second elongation (i.e. after an accommodation cycle), at 50% elongation (denoted MA50), at 100% elongation (denoted MA100) and at 300% elongation (denoted MA300). The stresses at break (in MPa) are also measured. All these tensile measurements are carried out under standard temperature (23 ± 2°C) and hygrometry (50 ± 5% relative humidity) conditions, according to the French standard NF T 40-101 of December 1979 and under the following temperature conditions: 100 ± 2°C. I-2) Measurement of the BET specific surface area

[0035] The BET specific surface area is determined in a known manner by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" Vol. 60, page 309, February 1938, more precisely according to the French standard NF ISO 9277 of December 1996 (multipoint volumetric method (5 points) - gas: nitrogen - degassing: 1 hour at 160°C - relative pressure range p / po : 0.05 to 0.17). The CTAB specific surface area is the external surface area determined according to the French standard NF T 45-007 of November 1987 (method B). II. DETAILED DESCRIPTION

[0036] Thus, the invention relates to a rubber composition based on at least: a copolymer A with a content greater than or equal to 50 phr, said copolymer A being a copolymer based on at least one ethylene monomer and at least one vinyl acetate monomer, an inorganic reinforcing filler which is characterized by the presence of hydroxyl groups on its surface, the content of inorganic reinforcing filler being greater than or equal to 20 phr, as a coupling agent between said copolymer A and said inorganic reinforcing filler a copolymer B different from said copolymer A, said copolymer B being a copolymer based on at least one alpha-olefin monomer and at least one functional monomer Y, the functional monomer Y being chosen from monomers carrying an epoxide function and monomers carrying a carboxylic acid function, the molar percentage of said functional monomer Y in said copolymer B is greater than or equal to 0.5%, and a crosslinking system with peroxides.

[0037] In this description, unless expressly indicated otherwise, all percentages (%) indicated are percentages by mass.

[0038] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the range of values ​​from more than "a" to less than "b" (i.e., excluding the limits a and b), while any interval of values ​​designated by the expression "from a to b" means the range of values ​​from "a" to "b" (i.e., including the strict limits a and b). In this document, when an interval of values ​​is designated by the expression "from a to b", the interval represented by the expression "between a and b" is also and preferably designated.

[0039] The abbreviation "pce" (usually "phr" in English for "per hundred part of rubber") means parts by weight per hundred parts by weight of elastomer (or of the total of elastomers if several elastomers are present) or rubber present in the rubber composition. The use of this unit is conventional in the field of rubber compositions. By extension, for the compositions of the invention, the abbreviation "pce" will also mean parts by weight per hundred parts by weight of copolymer A. When the composition comprises, for example, a coupling of copolymer A and elastomer, the sum of the mass contents of copolymer A and of the elastomer(s) is equal to 100 pce and the mass content of the other constituents of the composition is expressed in pce relative to the 100 pce of copolymer A and of the elastomer(s).

[0040] By "rubber composition based on" is meant a rubber composition comprising the mixture and / or the reaction product of the different constituents used, some of these basic constituents being capable of, or intended to react with each other, at least in part, during the different phases of manufacture of the composition, in particular during its crosslinking or vulcanization.

[0041] Usually in the present application, the terms “elastomer” and “rubber” are used interchangeably in the present description. These terms are interchangeable.

[0042] By "polymer" we mean a linear or branched macromolecule having a sequence made up of several repeating units (or monomeric unit), these repeating units being able to have the same chemical structure or a different chemical structure (we will then possibly speak of a copolymer or a terpolymer).

[0043] All glass transition temperature “Tg” values ​​are measured in a known manner by DSC (Differential Scanning Calorimetry) according to ASTM D3418 of 1999 unless expressly stated otherwise.

[0044] For example, the quantity (in mass or in mol) of each monomer inside the polymer, i.e. copolymer A, copolymer B and polymer C, can be measured using known Fourier transform infrared spectroscopy techniques and the ISO8985 standard of 1998.

[0045] According to the invention, the carbon products mentioned in the description may be of fossil or bio-sourced origin. In the latter case, they may be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. This concerns in particular the compounds (such as monomers, polymers), reagents and other components mentioned in the description, such as fillers, etc. o Copolymer A

[0046] The rubber composition in accordance with the invention comprises at least one copolymer A, at a rate greater than or equal to 50 pce, said copolymer A being a copolymer based on at least one ethylene monomer and at least one vinyl acetate monomer.

[0047] By "copolymer based on at least one ethylene monomer and at least one vinyl acetate monomer" is meant a polymer based on at least one or more ethylene monomers and at least one or more vinyl acetate monomers. This type of copolymer is well known to those skilled in the art under the name EVA copolymer. This copolymer can therefore result from the polymerization of ethylene monomers (E monomers) and vinyl acetate monomers (VA monomers). It is understood that other monomers different from the ethylene and vinyl acetate monomers can optionally be present in the copolymer. This or these different monomers (X monomers) have polymerizable functions of identical or substantially identical reactivity with the E monomers and the VA monomers and can be distributed statistically along the chain of the copolymer.

[0048] The monomers X may be chosen from unsaturated carboxylic acid esters such as, for example, C1-C10 alkyl acrylates or C1-C10 alkyl methacrylates, alpha-olefins such as propene, 1-butene, 1-hexene, monomers bearing an epoxide function, monomers bearing an anhydride function, monomers bearing a carboxylic acid function. The following monomers are particularly suitable as monomer X: C1-C10 alkyl acrylates, C1-C10 alkyl methacrylates, glycidyl methacrylate, glycidyl acrylate, maleic anhydride, hemiesters of maleic anhydride, acrylic acid and methacrylic acid.

[0049] The composition according to the invention may comprise one or more copolymers A, i.e. a mixture or coupling of two or more different copolymers A. For example, the composition may comprise a copolymer of ethylene and vinyl acetate and a terpolymer of ethylene / vinyl acetate / monomer X or when the copolymer A consists of monomer of ethylene and vinyl acetate, the composition may comprise copolymers having different molar contents of ethylene monomers.

[0050] Copolymer A (or the mixture of copolymers A) is (are) the majority copolymer of the composition of the invention, that is to say that it (they) represents (represent) at least 50% by weight of the total weight of the polymers of the composition. In other words, the copolymer(s) A is (are) present in the composition at a rate greater than or equal to 50 phr, preferably strictly greater than 50 phr.

[0051] Preferably, the molar content of ethylene monomer in copolymer A is greater than or equal to 51%, preferably greater than or equal to 55%. More preferably, the molar content of ethylene monomer in copolymer A ranges from 57% to 90%, even more preferably ranges from 57% to 85%.

[0052] When copolymer A results from the copolymerization of ethylene monomers, vinyl acetate monomers and one or more monomers X, the molar percentage of the monomer(s) X (including that of the preferred monomers X above) is strictly less than 0.3%; the molar content of ethylene monomer is advantageously greater than or equal to 51%.

[0053] Preferably, when the copolymer A results from the copolymerization of ethylene monomers, vinyl acetate monomers and one or more monomers X, the molar percentage of the monomer(s) X (including that of the preferred monomers X above) is strictly less than 0.3%; the molar content of ethylene monomer advantageously ranges from 57% to 85%.

[0054] Preferably, copolymer A consists of ethylene monomers and vinyl acetate monomers. In other words, the sum of the molar percentages of ethylene monomers and vinyl acetate monomers in copolymer A is equal to 100%.

[0055] Copolymers A are preferably random polymers. They can be obtained in particular by high-pressure polymerization of the corresponding monomers using methods known to those skilled in the art. These copolymers can be obtained in particular using the methods described in documents EP0341499A2 and EP0307755A2.

[0056] The copolymers A described above have a glass transition temperature Tg in the vast majority of cases which is negative (i.e. less than 0°C, measured at atmospheric pressure). The Tg of the copolymers A described above is measured in a known manner by DSC (Differential Scanning Calorinetry) according to the ASTM D3418 standard of 1999.

[0057] Copolymers A are commercially available, notably from suppliers such as Arkema, EI du Pont de Nemours and Company, Arlanxeo.

[0058] According to one embodiment of the composition according to the invention, the content of copolymer A or of the mixture of copolymers A in the composition is equal to 100 pce. ∘ Polymer C

[0059] According to another embodiment of the invention, the composition may further comprise at least one polymer C different from the copolymer(s) A.

[0060] Preferably, this polymer C is a diene elastomer.

[0061] By "diene" elastomer, whether natural or synthetic, is meant an elastomer consisting at least in part (i.e. a homopolymer or a copolymer) of diene monomer(s) (i.e., bearing(s) two carbon-carbon double bonds, conjugated or not).

[0062] These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". "Essentially unsaturated" generally means a diene elastomer derived at least in part from conjugated diene monomers, having a content of units or motifs of diene origin (conjugated dienes) which is greater than 15% (mol %); thus, diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins such as EPDM do not fall within the previous definition and can be described in particular as "essentially saturated" diene elastomers (content of motifs of diene origin, low or very low, always less than 15% (mol %)).In the category of "essentially unsaturated" diene elastomers, a "highly unsaturated" diene elastomer is understood to mean in particular a diene elastomer having a molar content of units of diene origin (conjugated dienes) which is greater than 50% (in mol).

[0063] Given these definitions, the term diene elastomer capable of being used in the compositions in accordance with the invention is understood more particularly to mean: (a) - any homopolymer of a conjugated diene monomer, in particular any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms; (b) - any copolymer obtained by copolymerization of one or more conjugated dienes with each other or with an ethylene monomer or with one or more aromatic vinyl compounds having from 8 to 20 carbon atoms; (c) - a ternary copolymer obtained by copolymerization of ethylene, an α-olefin having from 3 to 6 carbon atoms with a non-conjugated diene monomer having from 6 to 12 carbon atoms, such as for example elastomers obtained from ethylene, propylene with a non-conjugated diene monomer of the aforementioned type such as in particular hexadiene-1,4, ethylidene norbornene, dicyclopentadiene; (d) - a copolymer of isobutene and isoprene (butyl rubber), as well as halogenated, in particular chlorinated or brominated, versions of this type of copolymer.

[0064] Although it applies to any type of diene elastomer, those skilled in the art of tires will understand that this embodiment is preferably implemented with essentially unsaturated diene elastomers, in particular of type (a) or (b) above.

[0065] Diene elastomers can have any microstructure which depends on the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the quantities of modifying and / or randomizing agent used. Diene elastomers can be, for example, block, random, sequenced, microsequenced, and can be prepared in dispersion or in solution; they can be coupled and / or star-shaped or even functionalized with a coupling and / or star-shaping or functionalizing agent.For coupling to a reinforcing inorganic filler such as silica, examples that may be mentioned are silanol or polysiloxane functional groups having a silanol end (as described for example in FR2740778A1 or US6013718, and WO2008 / 141702A1), alkoxysilane groups (as described for example in FR2765882A1 or US5977238), carboxylic groups (as described for example in WO01 / 92402A1 or US6815473, WO2004 / 096865A2 or US2006 / 0089445) or polyether groups (as described for example in EP1127909A1 or US6503973, WO2009 / 000750A1 and WO2009 / 000752A1).

[0066] Functional diene elastomers may also include those prepared by using a functional initiator, in particular those carrying an amine or tin function (see for example WO2010 / 072761A1).

[0067] As other examples of functionalized diene elastomers, usable in the invention, mention may also be made of elastomers (such as BR, NR or IR) of the epoxidized type.

[0068] Preferably, polymer C is a diene elastomer and has a molar content of diene unit of less than 15%. ∘ Inorganic reinforcing filler

[0069] As indicated above, the rubber composition of the invention comprises at least one inorganic reinforcing filler which is characterized by the presence of hydroxyl groups on its surface.

[0070] By "reinforcing inorganic filler" is meant here any inorganic or mineral filler, whatever its color and origin (natural or synthetic), also called "white" filler, "clear" filler or even "non-black" filler ("non-black filler") as opposed to carbon black; this inorganic filler being 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 tire-grade carbon black. The inorganic filler r reinforcing agent according to the invention is characterized by the presence of hydroxyl groups (-OH) on its surface, requiring, to be used as a reinforcing filler, the use of a coupling agent or system intended to ensure a stable chemical bond between the filler and the elastomeric matrix.

[0071] Suitable inorganic reinforcing fillers are, in particular, siliceous mineral fillers, preferably silica (SiO 2 ). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET surface area and a CTAB specific surface area both less than 450 m 2 < / g, preferably from 30 to 400 m 2 < / g, in particular between 60 and 300 m 2 < / g. Examples of highly dispersible precipitated silicas (known as "HDS") include "Ultrasil 7000" and "Ultrasil 7005" silicas from Evonik, "Zeosil 1165MP, 1135MP and 1115MP" silicas and "Zeosil Premium 200" silicas from Solvay, "Hi-Sil EZ150G" silicas from PPG, "Zeopol 8715, 8745 and 8755" silicas from Huber, and high specific surface silicas as described in application WO03 / 016387A1.

[0072] Of course, the term inorganic reinforcing filler also means mixtures of different reinforcing inorganic fillers, in particular highly dispersible silicas as described above or a mixture of inorganic fillers of the siliceous type and non-siliceous inorganic fillers. As non-siliceous inorganic fillers, mention may be made of mineral fillers of the aluminous type, in particular alumina (Al 2 O 3 ) or aluminum (oxide)hydroxides, or even reinforcing titanium oxides, for example those described in US6610261 and US6747087. The non-siliceous inorganic fillers, when present, are in the minority in the reinforcing filler.

[0073] The physical state in which the inorganic reinforcing filler is presented is indifferent, whether in the form of powder, microbeads, granules, or even balls.

[0074] Preferably, the inorganic reinforcing filler comprises silica. More preferably, the inorganic reinforcing filler consists of silica.

[0075] It is understood that the person skilled in the art knows how to apply the rate of inorganic reinforcing filler depending on the intended applications of the rubber composition.

[0076] The level of reinforcing filler in the rubber composition according to the invention is greater than or equal to 20 parts by weight per hundred parts of elastomer. Preferably, the level of reinforcing filler in the rubber composition according to the invention ranges from 30 to 80 parts by weight per hundred parts of elastomer.

[0077] A person skilled in the art will understand that, as a filler equivalent to the reinforcing inorganic filler described in this paragraph, a reinforcing filler of another nature, in particular organic such as carbon black, could be used, provided that this reinforcing filler is covered with an inorganic layer such as silica, or else comprises functional sites on its surface, in particular hydroxyl, requiring the use of a coupling agent to establish the bond between the filler and the copolymer(s) A. By way of example, mention may be made, for example, of carbon blacks for tires as described, for example, in patent documents WO96 / 37547A2 and WO99 / 28380A1. o Carbon black

[0078] According to one embodiment of the invention, the rubber composition may further comprise a reinforcing filler such as carbon black.

[0079] Carbon black, when present, may preferably be used at a level of less than or equal to 10 phr, preferably less than or equal to 5 phr. Preferably, the level of carbon black may range from 0.5 to 4 phr. These preferred ranges apply to any of the embodiments of the invention.

[0080] Suitable carbon blacks are all carbon blacks, in particular the blacks conventionally used in tires or their treads (so-called tire-grade blacks). Among the latter, we will mention more particularly the reinforcing carbon blacks of the 100, 200, 300 series, or the blacks of the 500, 600 or 700 series (ASTM grades), such as for example blacks N115, N134, N234, N326, N330, N339, N347, N375, N550, N683, N772). These carbon blacks can be used in the isolated state, as commercially available, or in any other form, for example as a carrier for certain of the rubber additives used. o Copolymer B

[0081] As seen previously, the rubber composition of the invention comprises at least one copolymer B, different from copolymer A, said copolymer B being a copolymer based on at least one alpha-olefin monomer and at least one functional monomer Y, the functional monomer Y being chosen from monomers carrying an epoxide function and monomers carrying a carboxylic acid function, the molar percentage of said functional monomer Y in said copolymer B is greater than or equal to 0.5%.

[0082] Copolymer B results from the copolymerization of one or more alpha-olefin monomer(s) and one or more functional monomer(s) Y. The molar percentage of the functional monomer(s) Y in copolymer B is at least 0.5%, preferably at least 0.7%. Even more preferably, the molar percentage of the functional monomer(s) Y in copolymer B ranges from 0.7 to 10%.

[0083] The functional monomer(s) Y of the copolymer B is (are) chosen from the group formed by monomers bearing an epoxide function and monomers bearing a carboxylic acid function. In other words, the function which is capable of physically and / or chemically bonding to the inorganic reinforcing filler is the carboxylic acid function or the epoxide function (or the hydroxyls resulting from the opening of the epoxide function).

[0084] Preferably, the functional monomer(s) Y of the copolymer B is (are) chosen from the group formed by aliphatic glycidyl ester monomers, aliphatic glycidyl ether monomers, alicyclic glycidyl ester monomers, alicyclic glycidyl ether monomers, acrylic acid monomers, salts of acrylic acid monomers, methacrylic acid monomers and salts of methacrylic acid monomers.

[0085] More preferably, the functional monomer(s) Y of the copolymer B is (are) a monomer carrying an epoxide function.

[0086] More preferably still, the functional monomer(s) Y of the copolymer B is (are) chosen from the group formed by aliphatic glycidyl ester monomers, aliphatic glycidyl ether monomers, alicyclic glycidyl ether ester monomers and alicyclic glycidyl ether monomers.

[0087] More preferably still, the monomer(s) Y of the copolymer B is (are) chosen from glycidyl methacrylates and glycidyl acrylates.

[0088] By "alpha-olefin monomer" is meant an alkene monomer having a carbon-carbon double bond between the first and second carbon atoms of said alkene (alpha position). Examples of alpha-olefin monomers include ethylene, propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene and 3-methyl-1-pentene.

[0089] Preferably, the alpha-olefin monomer of copolymer B is ethylene.

[0090] The copolymer B used in the present invention may also be a terpolymer, that is to say result from the polymerization of at least one alpha-olefin monomer, at least one functional monomer Y (as well as the preferred functional Y monomers) as defined above and at least one third monomer different from the two previous monomers.

[0091] Preferably, when copolymer B is a terpolymer, the third monomer is chosen from C1-C10 alkyl acrylates, C1-C10 alkyl methacrylates, alpha-olefin monomers other than ethylene, and vinyl esters of carboxylic acids. The alkyl chains of the acrylates and methacrylates may advantageously have from 1 to 6 carbon atoms.

[0092] More preferably, the third monomer is chosen from propylene, 1-butene, isobutene, methyl acrylates, ethyl acrylates, propyl acrylates, butyl acrylates, methyl methacrylates, ethyl methacrylates, propyl methacrylates, butyl methacrylates, vinyl acetate, vinyl ethanoate, vinyl propionate, vinyl butyrate.

[0093] Preferably, copolymer B is chosen from ethylene / glycidyl methacrylate polymers, ethylene / glycidyl acrylate copolymers, ethylene / C1-C10 alkyl acrylate / glycidyl methacrylate copolymers, ethylene / C1-C10 alkyl acrylate / glycidyl acrylate copolymers, ethylene / C1-C10 alkyl methacrylate / glycidyl methacrylate copolymers, ethylene / C1-C10 alkyl methacrylate / glycidyl acrylate copolymers, ethylene / vinyl acetate / glycidyl methacrylate copolymers and ethylene / vinyl acetate / glycidyl acrylate copolymers.

[0094] The copolymer B used in the present invention is a coupling agent, also called a bonding agent. The coupling agent has the function of ensuring the bond between the surface of the reinforcing inorganic filler particles and the copolymer A or copolymers A of the rubber composition, while facilitating the dispersion of this reinforcing inorganic filler within the elastomeric matrix, formed by the copolymer(s) A and optionally the polymer C. The use of a specific copolymer B as a coupling agent makes it possible to obtain compositions whose elastomeric matrix mainly comprises one or more copolymers A as described above, and which in particular have good reinforcing properties.

[0095] It is understood that those skilled in the art know how to adjust the level of copolymer B as a function of the level of inorganic reinforcing filler used in the compositions in accordance with the invention.

[0096] Preferably, the copolymer(s) B range(s) from 1 to 25 pce.

[0097] Preferably, the content of copolymer B is greater than or equal to 5% by weight relative to the weight of the inorganic reinforcing filler. Preferably, the content of copolymer B ranges from 5% to 30% by weight relative to the weight of the inorganic reinforcing filler.

[0098] Copolymer B can be obtained by any polymerization or grafting technique well known to those skilled in the art. Documents FR2569411A1, FR2498609A1, FR2660660A1, EP174244A1 and EP177378A1 illustrate methods for synthesizing copolymers B used in the compositions of the invention; in particular, these documents describe the production of ethylene-acrylate-other monomer terpolymers (in particular as cited above) under high pressure in an autoclave reactor.

[0099] B copolymers, in particular those carrying epoxy function(s), are commercially available from Arkema (under the name Lotader), Du Pont (certain Elvaloy) and Sumitomo (under the name Igetabond). ∘ Various additives

[0100] The rubber compositions in accordance with the invention may also comprise all or part of the usual additives usually used in rubber compositions, in particular intended for the manufacture of semi-finished articles, such as treads, and finished articles such as tires, such as for example pigments, protective agents such as anti-ozone waxes such as for example paraffin, chemical anti-ozonants, antioxidants, anti-fatigue agents and plasticizers. These compositions may also contain thermal stabilizers, slip or anti-blocking agents originating from commercial products of copolymers A and / or B sold in particular in powder or granule form in order to prevent the grains of powder or granule from sticking to each other. ∘ Peroxide crosslinking system

[0101] As previously specified, the composition of the invention comprises at least one peroxide crosslinking system.

[0102] The term "peroxide crosslinking system" means the use of one or more peroxides intended to crosslink a polymer, in particular a copolymer and / or an elastomer. The peroxide(s) form(s) during its (their) activation free radicals on the copolymer, in particular on the elastomer(s), which allows the crosslinking of the chains of the copolymer (of the elastomer) without the peroxide(s) being(s) integrated into these chains. Peroxides are well known to those skilled in the art.

[0103] Among the peroxides, well known to those skilled in the art, it is preferable to use for the invention at least one peroxide chosen from the family of organic peroxides. By organic peroxide is meant any hydrocarbon molecule comprising a function of the peroxy OO type. For example, useful organic peroxides are those which decompose rapidly in the temperature range of 140°C to 220°C.

[0104] The organic peroxides may advantageously be chosen from the families of dialkyl peroxides or peroxyesters. In particular, the organic peroxide(s) may be chosen from tert-butyl 2-ethylperhexanoate, dicumyl peroxide, benzoyl peroxide, dibenzoyl peroxide, ditertbutyl peroxide, tert-butylcumyl peroxide, 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, and mixtures thereof.

[0105] There are various packaged products on the market, known by their trademarks; these include: "Dicup" from Hercules Powder Co., "Perkadox Y12" from Noury ​​van der Lande, "Peroximon F40" from Montecatini Edison SpA, "Trigonox" from Noury ​​van der Lande, "Varox" from RTVanderbilt Co., and "Luperko" from Wallace & Tiernan, Inc.

[0106] Preferably, the quantity of peroxides to be used for the purposes of the invention is less than or equal to 3 phr. Preferably, the quantity of peroxides in the composition is within a range from 0.1 to 3 phr. More preferably, the quantity of peroxides in the composition is within a range from 0.2 to 2 phr.

[0107] The peroxide crosslinking system may further comprise a coagent and / or a solvent such as those described in particular in document WO2011 / 067504A1. ∘ Manufacture of the compositions in accordance with the invention

[0108] The rubber compositions of the invention are manufactured in suitable mixers, using two successive preparation phases according to a general procedure well known to those skilled in the art.

[0109] The first (non-productive) phase is preferably carried out in several thermomechanical stages. During a first stage, the copolymer A based on ethylene monomers and vinyl acetate monomers, optionally one or more elastomers different from the copolymer A based on ethylene monomers and vinyl acetate monomers, the inorganic reinforcing filler(s), the copolymer B and / or other ingredients with the exception of the peroxide crosslinking system, are introduced into a suitable mixer such as a conventional internal mixer, at a temperature between 20°C and 100°C and preferably between 25°C and 100°C.After a few minutes, preferably 0.5 to 2 min and a rise in temperature to reach 100°C, the other ingredients (i.e. those remaining if not all were added at the start) are added all at once or in parts, with the exception of the peroxide crosslinking system during mixing lasting from 20 seconds to a few minutes. The total mixing time, in this non-productive phase, is preferably between 2 and 10 minutes at a temperature less than or equal to 180°C, and preferably less than or equal to 170°C and under pressure of a few bar (1 bar = 100,000 Pa). The person skilled in the art knows how to adapt the pressure according to the mixer used.

[0110] After cooling the mixture thus obtained, the peroxide crosslinking system is then incorporated at low temperature (typically below 100°C), generally in an external mixer such as a cylinder mixer; everything is then mixed (second phase known as the productive phase) for a few minutes, for example between 5 and 15 min. A person skilled in the art knows how to choose the appropriate peroxide crosslinking system depending on the copolymers and polymers used and the temperature at which the crosslinking takes place.

[0111] The final composition thus obtained is then calendered, for example in the form of a sheet or plate, in particular for characterization in the laboratory, or extruded, to form for example a rubber profile used for the manufacture of semi-finished products in order to obtain products such as a tread. These products can then be used for the manufacture of tires, according to techniques known to those skilled in the art.

[0112] Crosslinking (or curing) is carried out in a known manner at a temperature generally between 130°C and 200°C, under pressure of a few tens of bars, for a sufficient time which can vary for example between 5 and 90 min depending in particular on the curing temperature, the crosslinking system adopted, the crosslinking kinetics of the composition considered or the size of the tire. ∘ Semi-finished article for tires

[0113] Another subject of the present invention relates to a semi-finished article for a tire comprising at least one crosslinkable (to be crosslinked) rubber composition (suitable or crosslinked) as defined above or capable of being obtained by the process described above.

[0114] A semi-finished product is a rubber product intended for the manufacture of tires. It can be any type of rubber strip, such as treads, underlays, crown reinforcement plies (for example working plies, protective plies or hooping plies), carcass reinforcement plies, sidewall plies, bead plies, protector plies, underlay plies, rubber block plies and other plies providing the interface between the aforementioned areas of the tires. Preferably, the semi-finished article is a tread. ∘ Pneumatic

[0115] The invention also relates to a tire comprising at least one semi-finished tire article as mentioned above or comprising at least one composition as defined above.

[0116] The tire according to the invention may be intended to equip in particular non-engine vehicles such as bicycles, passenger-type motor vehicles, SUVs (Sport Utility Vehicles), two-wheelers (in particular motorcycles), airplanes, industrial vehicles chosen from vans, heavy goods vehicles (i.e. the metro, buses, road machinery (trucks and trailers)), off-road vehicles, such as agricultural or civil engineering machinery, other transport or handling vehicles. ∘ Foam

[0117] The invention also relates to a foam or a foam article, in particular a foam or a foam article based on the above composition and blowing agents having insulating, soundproofing, anti-vibration or reinforcing properties, used in the field of sport and leisure - as a ball structure, protective shoulder pad. By "foam" or "foam structure" is meant an object or article or material of density lower than that of the starting product. ∘ Use as additives

[0118] The invention also relates to the use of the composition as defined above as impact additives (to increase the impact resistance) of thermoplastic materials, as additives for bitumen. ∘ Glue, wiring

[0119] The composition according to the invention can also be used in hot-melt structural adhesives or in the field of cabling, in particular as an insulating layer or as a flame-retardant layer; in the latter use, the composition can advantageously contain a non-halogenated fire-resistant additive. III. EXAMPLES

[0120] The following examples illustrate the invention; however, the latter cannot be limited to these examples alone. III-1) Preparation of compositions:

[0121] For the following tests, the compositions are prepared as follows: the copolymer(s) and polymer(s), the inorganic reinforcing filler (silica), the coupling agent are introduced into an internal mixer, filled to 70% and with an initial tank temperature of approximately 50°C, and then, after one to two minutes of mixing, the various other ingredients except for the crosslinking system or the vulcanization system. Thermomechanical work (non-productive phase) is then carried out in one step (total mixing time equal to approximately 5 min), until a maximum "drop" temperature of approximately 165°C at atmospheric pressure (Pa) is reached.

[0122] The mixture thus obtained is recovered, cooled and then the crosslinking system (peroxides) or vulcanization (sulfur and accelerator) is added to an external mixer (homo-finisher) at 70°C, mixing everything (productive phase) for approximately 5 to 6 min.

[0123] The compositions thus obtained are then calendered either in the form of plates (thickness of 2 to 3 mm) or thin sheets of rubber for the measurement of their physical or mechanical properties after curing, or in the form of profiles which can be used directly, after cutting and / or assembly to the desired dimensions, for example as semi-finished products for tires, in particular as tire treads.

[0124] To be used in tires, rubber compounds must have a certain number of properties, including rigidity that changes little with temperature, good reinforcement and good breaking stress.

[0125] More particularly, for the composition according to the present invention, these properties are obtained when: (a) the ratio of the nominal secant moduli at 50% elongation (MA50) measured at 23°C and at 100°C is less than or equal to 2, i.e. ((MA50 (at 23°C) / MA50 (at 100°C) ≤ 2); (b) the ratio of the nominal secant moduli at 100% elongation (MA100) measured at 23°C and at 100°C is less than or equal to 2, i.e. ((MA100 (at 23°C) / MA100 (at 100°C) ≤ 2); (c) the ratio of the nominal secant modulus at 300% elongation (MA 300) measured at 23°C to the nominal secant modulus at 100% elongation (MA 100) measured at 23°C is greater than or equal to 3 or ((MA300 (at 23°C) / MA100 (at 23°C) ≥ 3); (d) the ratio of the nominal secant modulus at 300% elongation (MA 300) measured at 100°C and the nominal secant modulus at 100% elongation (MA 100) measured at 100°C is greater than or equal to 3 or ((MA300 (at 100°C) / MA100 (at 100°C) ≥ 3); (e) a nominal breaking stress strictly greater than 12.5 MPa; (f) a nominal secant modulus at 300% elongation measured at 23°C (MA300) strictly greater than 7.5 MPa.

[0126] Measurements (a) and (b) relate to the change in stiffness as a function of temperature. Measurements (c) and (d) relate to the reinforcement properties at low temperature (23°C) and high temperature (100°C) respectively. Measurement (e) represents the resistance to large deformations. Measurement (f) relates to the stiffness of the rubber composition.

[0127] Composition T1 is a control composition conventionally used and marketed for the manufacture of tire treads. It meets criteria (a) to (f) listed above, and therefore has the properties sought for use in tires.

[0128] Attempts have been made to obtain these properties, or even to improve some of them, by modifying the elastomer used. These modifications are detailed in tests A. Tests B to D illustrate other embodiments of the invention. III-2) Test A:

[0129] The examples presented in Table 1 are intended to compare the different rubber properties of composition C1 in accordance with the invention with a series of control compositions (T1 to T4). The results of the properties measured after curing are presented in Table 2.

[0130] The rates of the various constituents of the compositions presented in Table 1 are expressed in pce (part by weight per hundred parts by weight of elastomer).

[0131] Although the pce levels of silica and coupling agent vary, the control compositions (T1, T2, T4) and the composition according to the invention (C1) comprise the same volume fraction of silica (16% by volume) and the same mass percentage of coupling agent relative to the silica (10%) with the exception of composition T3 which does not comprise a coupling agent. Composition T3 has a volume fraction of silica of approximately 16% by volume. These compositions can therefore be compared with each other. Table 1: Composition T1 T2 T3 T4 C1 Elastomer (1) 100 100 (-) (-) (-) Copolymer A1 (2) (-) (-) 100 100 100 Silica (3) 45 45 45 45 43,5 Coupling agent (4) 4,5 4,5 (-) 4,5 (-) Coupling agent (5) (-) (-) (-) (-) 4,35 Crosslinking system (6) 1,5 (-) (-) (-) (-) Crosslinking system (7) (-) 1,5 1,5 1,5 1,5 (1) Styrene-butadiene elastomer SBR comprising 27% styrene and in the polybutadiene part 24% -1,2 (vinyl) units, 28% -1,4 cis units and 48% -1,4 trans units; its glass transition temperature Tg, measured by DSC (Differential Scanning Calorimetry) according to the ASTM D3418 standard of 1999 is equal to - 48°C; (2) Copolymer A1: Ethylene / vinyl acetate copolymer (EVA) marketed by Arkema under the reference Evatane 42-60. Copolymer A1 has a molar percentage of ethylene monomer (E) equal to 81% and a molar percentage of vinyl acetate monomer (VA) equal to 19%.It has an MFI at 190°C ranging from 65 to 85 g / 10 min (MFI = Melt Flow Index and measured according to the ISO 1133 standard of 2011) and a melting temperature Tf, measured according to the ISO 11357 standard of 2013, equal to 48°C; (3) Silica “160 MP” marketed by Solvay and whose BET specific surface area measured by the method described in paragraph I-2) is 160 m 2 < / g; (4) Coupling agent: bis(3-triethoxysilpropyl) tetrasulfide (TESPT) marketed by Evonik under the reference “SI69”; (5) Coupling agent: copolymer B1 marketed by Arkema under the reference Lotader AX8900. Copolymer B1 has a molar percentage of ethylene monomer (E), methyl acrylate monomer (MA) and glycidyl methacrylate monomer (GMA) respectively equal to 88%; 10% and 2%; (6) Sulfur vulcanization system comprising 1.5 phr of sulfur and 1.5 phr of accelerator N-cyclohexyl-2-benzothiazyl-sulfenamide (CBS).The accelerator is marketed under the name “Santocure CBS” by Flexys; (7) Crosslinking system: dicumyl peroxide (DICUP) marketed by Sigma Aldrich.

[0132] Composition T2 differs from composition T1 in the nature of the crosslinking agent. The sulfur crosslinking (vulcanization) system of composition T1 has been replaced by peroxide crosslinking.

[0133] Composition T3 differs from composition T2 in that it does not include a coupling agent. In addition, the chemical nature of the elastomer is different. The styrene-butadiene copolymer (SBR) in composition T2 has been replaced by a copolymer based on ethylene and vinyl acetate (EVA) (copolymer A1).

[0134] Composition T4 differs from composition T3 by the presence of a coupling agent usually used for rubber compositions. This is an organosilane polysulfide.

[0135] The composition according to the invention (C1) differs from composition T4 by the nature of the coupling agent. The coupling agent usually used in rubber compositions, intended in particular for tires, has been replaced by a copolymer based on at least one alpha-olefin monomer and at least one functional monomer Y (copolymer B1).

[0136] The properties of the compositions obtained after cooking (approximately 20 min at 170°C) are presented in Table 2 below. Table 2 Composition No. T1 T2 T3 T4 C1 MA50 (at 23°C) / MA50 (at 100°C) 1,0 0,9 2,1 9,7 2,0 MA100 (at 23°C) / MA100 (at 100°C) 1,1 1,0 1,9 9,9 1,9 MA300 (at 23°C) / MA100 (at 23°C) 4,3 NC 2,2 2,5 3,0 MA300 (at 100°C) / MA100 (at 100°C) 4,2 NC 2,8 1,5 3,6 Nominal stress at break in MPa (at 23°C) 21,4 12,3 20,8 10,0 24,2 MA300 in MPa (at 23°C) 9,7 NC 7,2 6,7 10,1 NC: not communicated because it was not possible to carry out the measurements.

[0137] Compared to the T1 composition, the T2 composition has too much rigidity and breaks even before the MA 300 modulus measurement is carried out. This composition is not acceptable for use in a tire.

[0138] By replacing the SBR elastomer with an EVA copolymer and removing the coupling agent, the control composition T3 is obtained which, compared to the control composition T2, exhibits a less good change in rigidity at temperature than the control composition T2 but is nevertheless acceptable (conditions (a) and (b) respected). The breaking stress of the composition T3 has been improved compared to that of the composition T2 and is at an acceptable level for the use considered (condition (e) respected). The reinforcement at 23°C and at 100°C is significantly improved compared to that of the control composition T2; however, the desired level is not reached (conditions (c) and (d) not respected). The same is true for the rigidity (condition (f) not respected). This control composition T3 does not exhibit all of the desired properties.

[0139] A coupling agent commonly used in rubber compositions intended for tires, such as the organosilane bis(3-triethoxysilylpropyl) tetrasulfide, was added to the control composition T3 (control composition T4 was obtained). As expected, the reinforcing properties at 23°C (condition (c)) of the control composition T4 were improved compared to those of the control composition T3. However, all other properties were degraded and this control composition T4 is not suitable for tire use.

[0140] Surprisingly, by replacing the organosilane tetrasulfide coupling agent with a copolymer based on at least one alpha-olefin monomer and at least one Y functional monomer (copolymer B1), it is found that the composition C1 according to the invention exhibits all of the desired properties. Indeed, the composition C1 according to the invention exhibits a rigidity which does not change or changes little as a function of the temperature (conditions (a) and (b) respected), good reinforcing properties at 23°C and 100°C (conditions (c) and (d) respected), a good breaking stress and a good rigidity (conditions (e) and (f) respected respectively). The breaking stress and rigidity properties of the composition C1 according to the invention are even superior to those of the control composition T1. III-3) Test B:

[0141] The examples presented in Table 3 are intended to show the rubber properties of the compositions in accordance with the invention C1 to C3 as a function of the level of specific coupling agent used. The results of the properties measured after curing are presented in Table 4 and are compared with the results of the control composition T3 previously described.

[0142] The rates of the different constituents of compositions C1 to C3 and T3 presented in Table 3 are expressed in pce. All compositions have the same volume fraction of silica (16%). Only the rate of coupling agent varies. Table 3 Composition T3 C2 C1 C3 Copolymer A1 (1) 100 100 100 100 Silica (2) 45 43 43,5 46 Coupling agent (3) (-) 2,15 4,35 9,2 Crosslinking system (4) 1,5 1,5 1,5 1,5 Mass percentage of coupling agent relative to the mass of silica 0 5 10 20 (1) Copolymer A1: ethylene / vinyl acetate (EVA) copolymer marketed by Arkema under the reference Evatane 42-60. Copolymer A1 has a molar percentage of ethylene monomer (E) equal to 81% and a molar percentage of vinyl acetate monomer (VA) equal to 19%. It has an MFI at 190°C ranging from 65 to 85 g / 10 min (MFI = Melt Flow Index and measured according to the ISO 1133 standard of 2011) and a melting temperature Tf, measured according to the ISO 11357 standard of 2013, equal to 48°C; (2) “160 MP” silica marketed by Solvay and whose BET specific surface area measured by the method described in paragraph I-2) is 160 m 2 < / g. (3) Coupling agent: Copolymer B1 marketed by Arkema under the reference Lotader AX8900.Copolymer B1 has a molar percentage of ethylene monomer (E), methyl acrylate monomer (MA) and glycidyl methacrylate monomer (GMA) respectively equal to 88%; 10% and 2%; (4) Crosslinking system: dicumyl peroxide (DICUP) marketed by Sigma Aldrich.

[0143] The properties obtained after cooking (approximately 20 min at 170°C) of the compositions are presented in table 4 below. Table 4 Composition N° T3 C2 C1 C3 MA50 (at 23°C) / MA50 (at 100°C) 2,1 2,0 2,0 2,0 MA100 (at 23°C) / MA100 (at 100°C) 1,9 1,9 1,9 2,0 MA300 (at 23°C) / MA100 (at 23°C) 2,2 3,0 3,0 3,1 MA300 (at 100°C) / MA100 (at 100°C) 2,8 3,7 3,6 4,0 Nominal stress at break in MPa (at 23°C) 20,8 24,3 24,2 23,8 MA300 in MPa (at 23°C) 7,2 10,5 10,1 12,4

[0144] Composition C1 of this test is identical to composition C1 of test A. Compositions C2 and C3 according to the invention represent another embodiment of the invention in which the level of coupling agent (copolymer B1) has been modified. This level was gradually increased from C2 to C1 then to C1 to C3.

[0145] Table 4 shows the properties of compositions C1 to C3 according to the invention compared to a control composition T3 which does not comprise any coupling agent.

[0146] It is noted that the three compositions according to the invention C1 to C3 have a rigidity which does not change or changes little with respect to the temperature, just like the control composition T3. However, the compositions C1 to C3 according to the invention have better reinforcement properties at 23°C and at 100°C, and surprisingly, a better breaking stress and a better rigidity compared to those of the control composition T3, and this whatever the level of copolymer coupling agent B1 used. III-4) Test C:

[0147] The examples presented in Table 5 are intended to show the rubber properties of the compositions according to the invention C1, C4 and C5 which comprise different copolymers A. The results of the properties measured after curing are presented in Table 6 and are compared with the results of the control composition T1 previously described.

[0148] The rates of the different constituents of compositions C1, C4 and C5 and T1 presented in Table 5 are expressed in pce. All compositions have the same volume fraction of silica (16%) and the same mass percentage of coupling agent relative to silica (10%). These compositions are comparable with each other. Table 5 Composition T1 C1 C4 C5 Elastomer (1) 100 (-) (-) (-) Copolymer A1 (2) (-) 100 (-) (-) Copolymer A2 (3) (-) (-) 100 (-) Copolymer A3 (4) (-) (-) (-) 100 Silica (5) 45 43,5 43,5 43,5 Coupling agent (6) 4,5 (-) (-) (-) Coupling agent (7) (-) 4,35 4,35 4,35 Crosslinking system (8) 1,5 (-) (-) (-) Crosslinking system (9) (-) 1,5 1,5 1,5 (1) Styrene-butadiene copolymer SBR comprising 27% styrene and in the polybutadiene part 24% -1,2 (vinyl) units, 28% -1,4 cis units and 48% -1,4 trans units; its glass transition temperature Tg, measured by DSC (Differential Scanning Calorimetry) according to ASTM D3418 of 1999 is equal to -48°C. (2) Copolymer A1: ethylene / vinyl acetate (EVA) copolymer marketed by Arkema under the reference Evatane 42-60. Copolymer A1 has a molar percentage of ethylene monomer (E) equal to 81% and a molar percentage of vinyl acetate monomer (VA) equal to 19%. It has an MFI at 190°C ranging from 65 to 85 g / 10 min (MFI = Melt Flow Index and measured according to the ISO 1133 standard of 2011) and a melting temperature Tf, measured according to the ISO 11357 standard of 2013, equal to 48°C; (3) Copolymer A2: ethylene / vinyl acetate copolymer (EVA) marketed by Arlanxeo under the reference LEVAPREN 500.Copolymer A2 has a molar percentage of ethylene monomer (E) equal to 75% and a molar percentage of vinyl acetate monomer (VA) equal to 25%. It has a Mooney viscosity index equal to 27±4 UM (Mooney index 1+4 at 100°C measured according to standard ASTM D1646 (UM = Mooney unit, 1UM=0.83 Newton.meter); (4) Copolymer A3: ethylene / vinyl acetate (EVA) copolymer marketed by Arlanxeo under the reference LEVAPREN 700. Copolymer A3 has a molar percentage of ethylene monomer (E) equal to 30% and a molar percentage of vinyl acetate monomer (VA) equal to 70%.It has a Mooney viscosity index equal to 27±4 UM (Mooney index 1+4 at 100°C measured according to the ASTM D1646 standard; (5) “160 MP” silica marketed by Solvay and whose BET specific surface area measured by the method described in paragraph I-2) is 160 m 2 < / g; (6) Coupling agent: bis(3-triethoxysilylpropyl) tetrasulfide (TESPT) marketed by Evonik under the reference “SI69”; (7) Coupling agent: Copolymer B1 Lotader AX8900 marketed by Arkema (mass percentage of ethylene (E), methyl acrylate (MA) and glycidyl methacrylate (GMA) monomers (E / MA / GMA 68 / 24 / 8 respectively); (8) Sulfur vulcanization system comprising 1.5 pce of sulfur and 1.5 pce of N-cyclohexyl-2-benzothiazyl-sulfenamide (CBS) accelerator. The accelerator is marketed under the name “Santocure CBS” by Flexys; (9) Crosslinking system: dicumyl peroxide (DICUP) marketed by Sigma Aldrich.

[0149] The properties obtained after cooking (approximately 20 min at 170°C) of the compositions are presented in table 6 below. Table 6 Composition No. T1 C1 C4 C5 MA50 (at 23°C) / MA50 (at 100°C) 1,0 2,0 1,9 2,0 MA100 (at 23°C) / MA100 (at 100°C) 1,1 1,9 1,8 1,8 MA300 (at 23°C) / MA100 (at 23°C) 4,3 3,0 3,7 3,9 MA300 (at 100°C) / MA100 (at 100°C) 4,2 3,6 4,6 4,9 Nominal stress at break in MPa (at 23°C) 21,4 24,2 24,9 21,6 MA300 in MPa (at 23°C) 9,7 10,1 9,9 9,4

[0150] Compositions T1 and C1 of this test are identical to compositions T1 and C1 of test A. Compositions C4 and C5 represent another embodiment of the invention in which the nature of copolymer A is different.

[0151] Table 6 shows that the properties of compositions C4 and C5 according to the invention are comparable to the properties of composition C1 according to the invention. All of the compositions according to the invention C1, C4 and C5 have the desired properties in terms of change in rigidity as a function of temperature, reinforcement at 23°C and at 100°C, breaking stress and rigidity. Some of these properties are even improved compared to those of the control composition T1 conventionally used for the manufacture of treads, intended to equip tires (composition T1). III-5) Test D:

[0152] The examples presented in Table 7 are intended to show the rubber properties of the compositions in accordance with the invention C3, C6 and C7 as a function of the different coupling agents (copolymers B) used. The results of the properties measured after curing are presented in Table 8 and are compared with the results of the control composition T3 previously described.

[0153] The rates of the different constituents of compositions C3, C6 and T3 presented in Table 7 are expressed in pce. All compositions have the same volume fraction of silica (16%) and the same mass percentage of coupling agent relative to silica (20%) with the exception of composition T3 which does not include a coupling agent. These compositions are comparable with each other. Table 7 Composition T3 C3 C6 C7 Copolymer A1 (1) 100 100 100 100 Silica (2) 45 46 46 46 Coupling agent (3) (-) 9,2 (-) (-) Coupling agent (4) (-) (-) 9,2 (-) Coupling agent (5) (-) (-) (-) 9,2 Crosslinking system (6) 1,5 1,5 1,5 1,5 (1) Copolymer A1: ethylene / vinyl acetate (EVA) copolymer marketed by Arkema under the reference Evatane 42-60. Copolymer A1 has a molar percentage of ethylene monomer (E) equal to 81% and a molar percentage of vinyl acetate monomer (VA) equal to 19%. It has an MFI at 190°C ranging from 65 to 85 g / 10 min (MFI = Melt Flow Index and measured according to the ISO 1133 standard of 2011) and a melting temperature Tf, measured according to the ISO 11357 standard of 2013, equal to 48°C; (2) Silica “160 MP” marketed by the company Solvay and whose BET specific surface area measured by the method described in paragraph I-2) is 160 m 2 < / g; (3) Coupling agent: Copolymer B1 marketed by Arkema under the reference Lotader AX8900.This copolymer B1 has a molar percentage of ethylene monomer (E), methyl acrylate monomer (MA) and glycidyl methacrylate monomer (GMA) respectively equal to 88%; 10% and 2%; (4) Coupling agent: Copolymer B2 marketed by Arkema under the reference Lotader AX8930. This copolymer B2 has a molar percentage of ethylene monomer (E), methyl acrylate monomer (MA) and glycidyl methacrylate monomer (GMA) respectively equal to 89%; 10% and 1%; (5) Coupling agent: Copolymer B3 EVA-GMA copolymer synthesized by the company Arkema according to the process described in EP174244A1 or EP177378A1). This copolymer B3 has a molar percentage of ethylene monomer (E), vinyl acetate monomer (VA) and glycidyl methacrylate monomer (GMA) respectively equal to 80%; 18% and 2%; (6) Crosslinking system: dicumyl peroxide (DICUP) marketed by Sigma Aldrich.

[0154] The properties obtained after cooking (approximately 20 min at 170°C) of the compositions are presented in table 8 below. Table 8 Composition No. T3 C3 C6 C7 MA50 (at 23°C) / MA50 (at 100°C) 2,1 2,0 2,0 1,9 MA100 (at 23°C) / MA100 (at 100°C) 1,9 2,0 2,0 1,8 MA300 (at 23°C) / MA100 (at 23°C) 2,2 3,1 3,0 3,1 MA300 (at 100°C) / MA100 (at 100°C) 2,8 4,0 3,6 3,7 Nominal stress at break in MPa (at 23°C) 20,8 23,8 25,0 29,1 MA300 in MPa (at 23°C) 7,2 12,4 14,8 11,9

[0155] Compositions T3 and C3 of this test are identical to compositions T3 and C3 of test B. Compositions C6 and C7 represent other embodiments of the invention in which the nature of the coupling agent (copolymer B) is different from that of the previous compositions.

[0156] Table 8 shows that the properties of compositions C6 and C7 according to the invention are comparable to the properties of composition C3 according to the invention. All of the compositions according to the invention C3, C6 and C7 have the desired properties in terms of change in stiffness as a function of temperature, reinforcement at 23°C and 100°C, breaking stress and stiffness.

Claims

1. Rubber composition based on at least: - a copolymer A with a content of greater than or equal to 50 phr, said copolymer A being a copolymer based on at least one ethylene monomer and on at least one vinyl acetate monomer, - a reinforcing inorganic filler characterized by the presence of hydroxyl groups at its surface, the content of reinforcing inorganic filler is greater than or equal to 20 phr, - as agent for coupling between said copolymer A and said reinforcing inorganic filler, a copolymer B different from said copolymer A, said copolymer B being a copolymer based on at least one alpha-olefin monomer and on at least one functional monomer Y, the functional monomer Y of the copolymer B being chosen from monomers bearing an epoxide function and monomers bearing a carboxylic acid function, the molar percentage of said functional monomer Y in said copolymer B is greater than or equal to 0.5%, and - a peroxide crosslinking system.

2. Composition according to Claim 1, wherein the molar content of ethylene monomer in the copolymer A is greater than or equal to 51%, preferably greater than or equal to 55%, preferably ranges from 57% to 90%.

3. Composition according to any one of Claims 1 to 2, wherein the molar percentage of said functional monomer Y in said copolymer B is greater than or equal to 0.7%, preferably ranges from 0.7% to 10%.

4. Composition according to any one of the preceding claims, wherein the functional monomer Y of the copolymer B is a monomer bearing an epoxide function, said functional monomer Y being chosen from aliphatic glycidyl esters, aliphatic glycidyl ethers, alicyclic glycidyl esters and alicyclic glycidyl ethers.

5. Composition according to Claim 4, wherein the functional monomer Y of the copolymer B is chosen from glycidyl methacrylate and glycidyl acrylate.

6. Composition according to any one of Claims 1 to 5, wherein the alpha-olefin monomer of the copolymer B is ethylene.

7. Composition according to any one of Claims 1 to 6, also comprising a polymer C, different from the copolymer A and the copolymer B.

8. Composition according to Claim 7, wherein the polymer C is a diene elastomer having a molar content of diene units of less than 15%.

9. Composition according to any one of Claims 1 to 8, wherein the content of copolymer B ranges from 1 to 25 phr.

10. Composition according to any one of Claims 1 to 9, wherein the reinforcing inorganic filler comprises silica.

11. Semi-finished article for tyre comprising at least one composition in accordance with any one of Claims 1 to 10.

12. Tyre comprising at least one composition in accordance with any one of Claims 1 to 10 or comprising at least one semi-finished article for tyre in accordance with Claim 11.

13. Use of the composition in accordance with any one of Claims 1 to 10 in foams or foam articles, or as impact additives in thermoplastic materials, or as additives for bitumen, or else in structural hot-melt adhesives or in the field of cable making.