CONVEYOR BELT CONTAINING A COMPOSITION OF HIGHLY SATURATED ELASTOMER

Description

[0001] The present invention relates to conveyor belts having improved mechanical properties.

[0002] Conveyor belts, also known as conveyor belts or conveyor belts, are essentially endless belts and are usually supported and driven by motorized pulleys. They can thus transport materials or goods over varying distances, up to several kilometers.

[0003] In the mining and quarrying sectors in particular, conveyor belts are required to receive large quantities of ore, pebbles, rocks, etc., often in a rough manner. They must therefore have excellent mechanical properties for as long as possible to maximize their service life. Elongation at break is a particularly important mechanical property to consider given the deformations undergone by the conveyor belt when receiving heavy loads that may have aggressive indentations, such as rock.

[0004] It is therefore important to have conveyor belts whose rubber composition has good mechanical properties, in particular elongation at break.

[0005] For this purpose, document DE102017202753 proposes a rubber composition for conveyor belts based on styrene-butadiene copolymer (SBR) in which a carbon black and a plasticizer are dispersed before the incorporation of the other ingredients of the composition. Document JP10168257 describes compositions for conveyor belts based on ethylene-propylene-diene monomer rubber (EPDM) or ethylene-propylene copolymer (EPM).

[0006] Furthermore, conveyor belts must meet other requirements such as good abrasion resistance and good resistance to crack propagation. These two properties, like the maintenance of mechanical properties, help to increase the service life of conveyor belts containing a rubber composition.

[0007] However, it is always of interest to manufacturers to have compositions that allow them to further improve the compromise between the aforementioned performances and thus have conveyor belts with the longest possible lifespan.

[0008] Continuing its research, the Applicant unexpectedly discovered that the use of a specific elastomer based on ethylene and 1,3-diene, the ethylene units in the copolymer representing more than 50% by mole of the monomer units of the copolymer, makes it possible to further improve the aforementioned performance compromise.

[0009] Thus, the subject of the invention is a conveyor belt comprising a rubber composition at least based on more than 50 pce of a copolymer of ethylene and 1,3-diene, the ethylene units in the copolymer representing more than 50% by mole of the monomer units of the copolymer, a filler and a crosslinking system, in which the volume fraction of filler in the composition is less than or equal to 19%. I- DEFINITIONS

[0010] The expression "based on" used to define the constituents of a catalytic system or a composition means the mixture of these constituents, or the product of the reaction of some or all of these constituents with each other, at least partially, during the different phases of manufacturing the catalytic system or the composition. In the case of a composition, it can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0011] By “elastomer matrix” is meant all the elastomers in the composition, including the copolymer defined below.

[0012] By the expression "part by weight per hundred parts by weight of elastomer" (or pce), it is meant, within the meaning of the present invention, the part, by mass per hundred parts of elastomer present in the rubber composition considered.

[0013] In this document, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0014] 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.

[0015] When a "majority" compound is referred to, within the meaning of the present invention, this compound is the majority among the compounds of the same type in the composition, i.e. it is the one that represents the largest quantity by mass among the compounds of the same type. Thus, for example, a majority elastomer is the elastomer representing the largest mass relative to the total mass of the elastomers in the composition. In the same way, a so-called majority filler is the one representing the largest mass among the fillers in the composition. For example, in a system comprising a single elastomer, this is the majority within the meaning of the present invention; and in a system comprising two elastomers, the majority elastomer represents more than half of the mass of the elastomers. On the contrary, a "minority" compound is a compound that does not represent the largest mass fraction among the compounds of the same type.Preferably by majority, we mean present at more than 50%, preferably more than 60%, 70%, 80%, 90%, and more preferably the “majority” compound represents 100%.

[0016] In the present application, the term "all the monomer units of the copolymer" or "all the monomer units of the copolymer" means all the repeating units constituting the copolymer which result from the insertion of the monomers into the copolymer chain by polymerization. Unless otherwise indicated, the contents of a monomer unit or repeating unit in the copolymer of ethylene and 1,3-diene are given as a molar percentage calculated on the basis of all the monomer units of the copolymer.

[0017] The compounds 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. Similarly, the compounds mentioned may also come from the recycling of materials already in use, i.e. they may be, partially or totally, derived from a recycling process, or obtained from raw materials themselves derived from a recycling process. This includes, in particular, polymers, plasticizers, fillers, etc.

[0018] Unless otherwise stated, all glass transition temperature “Tg” values ​​described herein are measured in a known manner by DSC (Differential Scanning Calorimetry) according to ASTM D3418 (1999). II- BRIEF DESCRIPTION OF THE FIGURES

[0019] [ Fig 1 ] There Figure 1represents a diagram of a cross-section of a conveyor belt. III- DESCRIPTION OF THE INVENTION III-1 Elastomeric matrix

[0020] The rubber composition of the conveyor belt according to the invention has the essential characteristic of being based on more than 50 pce of a copolymer of ethylene and 1,3-diene, the ethylene units in the copolymer representing more than 50% by mole of the monomer units of the copolymer. In the present, the “copolymer of ethylene and 1,3-diene, the ethylene units in the copolymer representing more than 50% by mole of the monomer units of the copolymer” may be designated by “copolymer” or by “copolymer of ethylene and 1,3-diene” for the sake of simplification of the wording.

[0021] The term "ethylene-1,3-diene copolymer" means any copolymer whose monomer units are those resulting from the polymerization of ethylene and a 1,3-diene. The ethylene-1,3-diene copolymer therefore results from the polymerization of only the monomers ethylene and 1,3-diene.

[0022] As is well known, the expression "ethylene unit" refers to the -(CH 2 -CH 2 )- motif resulting from the insertion of ethylene into the elastomer chain.

[0023] As is known, the term "1,3-diene unit" refers to the units resulting from the insertion of 1,3-diene by a 1,4-addition, a 1,2-addition or a 3,4-addition in the case of isoprene. The 1,3-diene units are those, for example, of a 1,3-diene or a mixture of 1,3-dienes, the 1,3-diene(s) having 4 to 12 carbon atoms, such as, in particular, 1,3-butadiene and isoprene. Preferably, the 1,3-diene is 1,3-butadiene.

[0024] Advantageously, the ethylene units in the copolymer represent between 50% and 95%, preferably between 55% and 90%, by mole of the monomer units of the copolymer.

[0025] The copolymer of ethylene and a 1,3-diene advantageously contains units of formula (I) and / or (II). The presence of a saturated 6-membered cyclic unit, 1,2-cyclohexanediyl, of formula (I) as a monomeric unit in the copolymer may result from a series of very specific insertions of ethylene and 1,3-butadiene into the polymer chain during its growth. -CH 2 -CH(CH=CH 2 )- (II)

[0026] For example, the copolymer of ethylene and a 1,3-diene may be devoid of units of formula (I). In this case, it preferably contains units of formula (II).

[0027] When the copolymer of ethylene and a 1,3-diene comprises units of formula (I) or units of formula (II) or units of formula (I) and units of formula (II), the molar percentages of the units of formula (I) and the units of formula (II) in the copolymer, respectively o and p, preferably satisfy the following equation (eq. 1), more preferably equation (eq. 2), o and p being calculated on the basis of all the monomer units of the copolymer. 0 < o + p ≤ 25 0 < o + p < 20

[0028] Advantageously also, the copolymer has a crystallinity of less than 20%, more advantageously less than 15%, even more advantageously less than 10%. The techniques used for the determination of the molar fractions, the average molar masses (Mn), the glass transition temperatures and the crystallinity are described below in the examples.

[0029] According to the invention, the copolymer of ethylene and a 1,3-diene (preferably 1,3-butadiene) is a random copolymer.

[0030] Advantageously, the number average mass (Mn) of the copolymer, preferably of the copolymer of ethylene and a 1,3-diene (preferably 1,3-butadiene) is within a range from 100,000 to 300,000 g / mol, preferably from 150,000 to 250,000 g / mol.

[0031] The copolymer can be obtained according to different synthesis methods known to those skilled in the art, in particular depending on the targeted microstructure of the copolymer. Generally, it can be prepared by copolymerization of at least one 1,3-diene, preferably 1,3-butadiene, and ethylene and according to known synthesis methods, in particular in the presence of a catalytic system comprising a metallocene complex. Mention may be made, in this respect, of catalytic systems based on metallocene complexes, which catalytic systems are described in documents EP 1 092 731, WO 2004035639, WO 2007054223 and WO 2007054224 in the name of the Applicant. The copolymer, including when it is random, can also be prepared by a process using a preformed type catalytic system such as those described in documents WO 2017093654 A1, WO 2018020122 A1 and WO 2018020123 A1.

[0032] The copolymer may consist of a mixture of ethylene and 1,3-diene copolymers which differ from each other in their microstructures and / or in their macrostructures.

[0033] Advantageously, the content of the ethylene and 1,3-diene copolymer in the composition of the conveyor belt according to the invention is within a range from 60 to 100 pce, preferably from 80 to 100 pce.

[0034] The elastomer matrix may advantageously comprise only, as elastomer, the copolymer of ethylene and 1,3-diene.

[0035] Alternatively, the elastomer matrix may further comprise a diene elastomer other than the ethylene and 1,3-diene copolymer (also referred to herein as "the other elastomer"). The other elastomer of the elastomer matrix of the tire according to the invention may be chosen from the group of highly unsaturated diene elastomers such as polybutadienes (abbreviated as "BR"), synthetic polyisoprenes (IR), natural rubber (NR), butadiene copolymers, isoprene copolymers and blends of these elastomers. The term "highly unsaturated diene elastomer" generally means a diene elastomer derived at least in part from conjugated diene monomers, having a content of units or patterns of diene origin (conjugated dienes) which is greater than 50% (mol %).

[0036] The other elastomer, when present, is in the minority, that is to say that it represents less than 50%, 40%, 30%, 20%, or even less than 10% by weight of the elastomer matrix. For example, the rate of the other elastomer, in the composition of the conveyor belt according to the invention, can be within a range from 0 to 40 phr, preferably from 0 to 20 phr. III-2 Charge

[0037] The composition of the conveyor belt according to the invention also has the essential characteristic of being based on a filler, the volume fraction of filler in the composition being less than 19%.

[0038] The volume fraction of filler in a rubber composition is defined as the ratio of the volume of the filler to the volume of all the constituents of the composition, it being understood that the volume of all the constituents is calculated by adding the volume of each of the constituents of the composition.

[0039] By filler is meant here any type of filler, whether reinforcing (typically with nanometric particles, and preferably with an average weight size of less than 500 nm, in particular between 20 and 200 nm) or non-reinforcing or inert (typically with micrometric particles, and preferably with an average weight size of greater than 1 µm, for example between 2 and 200 µm). The average weight size being measured in a manner well known to those skilled in the art (for example, according to application WO2009 / 083160 paragraph I.1). Examples of fillers known as reinforcing by those skilled in the art include carbon black or a reinforcing inorganic filler such as silica in the presence of a coupling agent, or a blend of these two types of filler. Indeed, as is known, silica is a reinforcing filler in the presence of a coupling agent allowing it to bind to the elastomer.Examples of fillers other than reinforcing fillers, or inert fillers known to those skilled in the art, include those chosen from the group consisting of ash (i.e., combustion residues), microparticles of natural (chalk) or synthetic calcium carbonates, synthetic or natural silicates (such as kaolin, talc, mica, cloisite), silicas (in the absence of a coupling agent), titanium oxides, aluminas, aluminosilicates (clay, bentonite), and mixtures thereof. Coloring or colored fillers, for example by pigments, may advantageously be used to color the composition according to the desired color. Preferably, the composition of the invention comprises a filler other than reinforcing chosen from the group consisting of chalk, talc, kaolin and mixtures thereof.

[0040] According to the invention, the filler advantageously comprises carbon black, silica or a mixture thereof. Preferably, the filler comprises more than 50% by weight, preferably more than 80% by weight of carbon black. More preferably, the filler consists exclusively of carbon black, i.e. the carbon black represents 100% by weight of the filler.

[0041] Suitable carbon blacks are all carbon blacks, including those conventionally used in tires or their treads. Among the latter, we will particularly mention the reinforcing carbon blacks of the 100, 200, 300 series, or the blacks of the 500, 600 or 700 series (ASTM D-1765-2017 grades), such as for example blacks N115, N134, N234, N326, N330, N339, N347, N375, N550, N683, N772. These carbon blacks can be used in their isolated state, as commercially available, or in any other form, for example as a carrier for some of the rubber additives used.

[0042] Among the aforementioned carbon blacks, those having a BET specific surface area in the range of 60 to 160 m 2 < / g are particularly preferred.

[0043] Thus, preferably, the filler comprises more than 50% by weight, preferably more than 80% by weight, of at least one carbon black having a BET specific surface area in a range from 60 to 160 m 2 < / g, preferably from 70 to 130 m 2 < / g, preferably from 100 to 120 m 2 < / g. The BET specific surface area of ​​the carbon blacks is measured according to the ASTM D6556-10 standard [multipoint method (at least 5 points) - gas: nitrogen - relative pressure range P / P0: 0.1 to 0.3].

[0044] Any type of precipitated silica is suitable as silica, in particular highly dispersible precipitated silicas (known as "HDS" for "highly dispersible" or "highly dispersible silica"). These precipitated silicas, whether highly dispersible or not, are well known to those skilled in the art. Examples include the silicas described in applications WO03 / 016215-A1 and WO03 / 016387-A1. Among the commercial HDS silicas, we can notably use the silicas “Ultrasil ®< 5000GR”, “Ultrasil ®< 7000GR” from the company Evonik, the silicas “Zeosil ®< 1085GR”, “Zeosil ®< 1115 MP”, “Zeosil ®< 1165MP”, “Zeosil ®< Premium 200MP”, “Zeosil ®< HRS 1200 MP” from the company Solvay.As non-HDS silica, the following commercial silicas can be used: silicas “Ultrasil ®< VN2GR”, “Ultrasil ®< VN3GR” from Evonik, silica “Zeosil ®< 175GR” from Solvay, silicas “Hi-Sil EZ120G(-D)”, “Hi-Sil EZ160G(-D)”, “Hi-Sil EZ200G(-D)”, “Hi-Sil 243LD”, “Hi-Sil 210”, “Hi-Sil HDP 320G” from PPG.

[0045] To couple the silica to the diene elastomer, it is possible to use, in a well-known manner, an at least bifunctional coupling agent (or bonding agent) intended to ensure a sufficient connection, of a chemical and / or physical nature, between the inorganic filler (surface of its particles) and the diene elastomer. In particular, at least bifunctional organosilanes or polyorganosiloxanes are used. By "bifunctional", we mean a compound having a first functional group capable of interacting with the inorganic filler and a second functional group capable of interacting with the diene elastomer. For example, such a bifunctional compound may comprise a first functional group comprising a silicon atom, said first functional group being capable of interacting with the hydroxyl groups of an inorganic filler and a second functional group comprising a sulfur atom, said second functional group being capable of interacting with the diene elastomer.

[0046] Preferably, when used, the organosilanes are chosen from the group consisting of polysulfurized organosilanes (symmetrical or asymmetrical) such as bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated to TESPT, marketed under the name “Si69” by the company Evonik or bis-(triethoxysilylpropyl) disulfide, abbreviated to TESPD, marketed under the name “Si75” by the company Evonik, polyorganosiloxanes, mercaptosilanes, blocked mercaptosilanes, such as S-(3-(triethoxysilyl)propyl) octanethioate marketed by the company Momentive under the name “NXT Silane”. More preferably, the organosilane is a polysulfurized organosilane.

[0047] When a silica-elastomer coupling agent is used, the coupling agent content can easily be adjusted by a person skilled in the art. Typically, the coupling agent content is from 0.5% to 15% by weight relative to the amount of silica.

[0048] The filler content can easily be adjusted by a person skilled in the art depending on the use of the rubber composition. Advantageously, the filler content, in the composition of the conveyor belt according to the invention, is within a range from 10 to less than 100 phr, preferably from 15 to 90 phr, more preferably from 20 to 75 phr. More particularly, the filler content, in the composition of the conveyor belt according to the invention, is within a range from 10 to less than 49 phr, preferably from 15 to 48 phr, more preferably from 20 to 47 phr.

[0049] Advantageously, the charge volume fraction is within a range from 10% to less than 19%, preferably from 10.5% to 18.5%, preferably from 11% to 18%, more preferably from 12% to 17%. III-3 Crosslinking system

[0050] The crosslinking system may be any type of system known to those skilled in the art in the field of tire rubber compositions. It may in particular be based on sulfur, and / or peroxide and / or bismaleimides.

[0051] Preferably, the crosslinking system is sulfur-based, in which case it is referred to as a vulcanization system. The sulfur can be provided in any form, in particular in the form of molecular sulfur and / or at least one sulfur-donating agent. At least one vulcanization accelerator is also preferably present, and, optionally, also preferably, various known vulcanization activators can be used, such as zinc oxide, stearic acid or equivalent compounds such as stearic acid salts and transition metal salts, guanidine derivatives (in particular diphenylguanidine), or even known vulcanization retarders.

[0052] Sulfur is used at a preferential rate of between 0.5 and 12 pce, in particular between 1 and 10 pce. The vulcanization accelerator is used at a preferential rate of between 0.5 and 10 pce, more preferably between 0.5 and 5.0 pce.

[0053] Any compound capable of acting as an accelerator for the vulcanization of diene elastomers in the presence of sulfur may be used as an accelerator, in particular accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include, but are not limited to, the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated as "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-tert-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-tert-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds. III-4 Plasticizing system

[0054] The rubber composition of the conveyor belt according to the invention may comprise a plasticizing system, but this is not obligatory.

[0055] For example, the rubber composition of the conveyor belt may not include a liquid plasticizer at 23°C, or may include less than 40 pce, preferably less than 30 pce.

[0056] Advantageously, the rubber composition of the conveyor belt comprises a liquid plasticizer at 23°C, preferably at a rate in a range from more than 0 to less than 40 pce, preferably from 2 to 30 pce, preferably from 3 to 20 pce.

[0057] The liquid plasticizer at 23°C may be chosen from the group consisting of naphthenic oils (low or high viscosity, in particular hydrogenated or not), paraffinic oils, MES oils, TDAE oils, RAE oils, TRAE oils, SRAE oils, mineral oils, vegetable oils, ether plasticizers, ester plasticizers, phosphate plasticizers, sulfonate plasticizers and mixtures thereof. Preferably, the liquid plasticizer at 23°C is chosen from the group consisting of MES oils, TDAE oils, naphthenic oils, vegetable oils and mixtures thereof.

[0058] Liquid plasticizers are said to be "low Tg", that is to say they have a Tg which is preferably lower than -20°C, preferably lower than -40°C

[0059] Furthermore, the rubber composition of the conveyor belt preferably does not comprise any hydrocarbon plasticizing resin (or plasticizing resin) or comprises less than 10 phr, preferably less than 5 phr. Particularly advantageously, the rubber composition of the conveyor belt does not comprise any hydrocarbon plasticizing resin. The term "resin" is known to those skilled in the art as a compound which is solid at room temperature (23°C), as opposed to a liquid plasticizing compound such as an oil. Plasticizing resins have been described, for example, in the work entitled " Hydrocarbon Resins" by R. Mildenberg, M. Zander and G. Collin (New York, VCH, 1997, ISBN 3-527-28617-9) of which chapter 5 is devoted to their applications, notably in pneumatic rubber (5.5. "Rubber Tires and Mechanical Goods") . III-5 Possible additives

[0060] The rubber composition of the conveyor belt according to the invention may optionally also comprise all or part of the usual additives usually used in elastomer compositions for conveyor belts, such as, for example, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents, etc. III-6 Conveyor belt

[0061] The conveyor belt according to the invention may be any type of conveyor belt comprising a rubber composition.

[0062] In simplified terms, with reference to the Figure 1 , a conveyor belt (1) comprises a loading layer (2), a reinforcing layer (3) and a driving layer (4). Conventionally, the reinforcing layer (3) is located between the loading layer (2) and the driving layer (4).

[0063] A conveyor belt loading layer can be defined as the layer of the conveyor belt on which loads of all types are received, for example consumer goods, materials such as rocks, pebbles or ore, etc. A conveyor belt reinforcing layer can be defined as a layer for strengthening the conveyor belt, in particular by limiting its deformation. A conveyor belt drive layer, also called a pulley cover layer, can be defined as the layer driven by any mechanical means, for example pulleys or motorized gears.

[0064] The reinforcing layer (3) may comprise a plurality of steel reinforcing elements (5), such as steel cables, which are embedded in the elastomeric matrix (6) of the reinforcing layer (3). The reinforcing layer (3) may alternatively consist of one or more fabric reinforcing layers (not shown).

[0065] The conveyor belt (1) may further comprise one or more further layers which may be located between the loading layer (2) and the reinforcing layer (3) and / or between the reinforcing layer (3) and the drive layer (4).

[0066] The composition of the conveyor belt according to the invention is particularly well suited to constituting the loading layer (2) of the conveyor belt (1).

[0067] Thus, the conveyor belt (1) according to the invention preferably comprises at least one loading layer (2), a reinforcing layer (3) and a driving layer (4), in which the loading layer (2) is made of a rubber composition of the conveyor belt described previously. III-7 Preparation of rubber compositions

[0068] The compositions in accordance with the invention can be manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art: a first working phase or thermomechanical mixing (so-called "non-productive" phase), which can be carried out in a single thermomechanical step during which all the necessary constituents, in particular the elastomer matrix, the reinforcing filler, any other various additives, with the exception of the crosslinking system, are introduced into a suitable mixer such as a conventional internal mixer (for example of the 'Banbury' type). The incorporation of the possible filler into the elastomer can be carried out in one or more stages by thermomechanical mixing. The non-productive phase can be carried out at high temperature, up to a maximum temperature of between 110°C and 200°C, preferably between 130°C and 185°C, for a duration generally of between 2 and 10 minutes.a second phase of mechanical work (so-called "productive" phase), which can be carried out in an external mixer such as a roller mixer, after cooling the mixture obtained during the first non-productive phase to a lower temperature, typically below 120°C, for example between 40°C and 100°C. The crosslinking system is then incorporated, and everything is then mixed for a few minutes, for example between 5 and 15 min.

[0069] Such phases have been described for example in applications EP-A-0501227, EP-A-0735088, EP-A-0810258, WO00 / 05300 or WO00 / 05301.

[0070] The final composition thus obtained is then calendered, for example, in the form of a sheet or plate, in particular for laboratory characterization, or extruded (or co-extruded with another rubber composition) in the form of a semi-finished (or profiled) rubber product that can be used, for example, as a conveyor belt loading layer. These products can then be used for the manufacture of conveyor belts, according to techniques known to those skilled in the art.

[0071] The composition can be either in the raw state (before crosslinking or vulcanization), or in the cured state (after crosslinking or vulcanization).

[0072] The crosslinking of the composition can be carried out in a manner known to those skilled in the art, for example at a temperature between 130°C and 200°C, under pressure. IV- PREFERRED EMBODIMENTS

[0073] In view of the foregoing, preferred embodiments of the invention are described below: 1. Conveyor belt comprising a rubber composition at least based on more than 50 pce of a copolymer of ethylene and 1,3-diene, the ethylene units in the copolymer representing more than 50% by mole of the monomer units of the copolymer, a filler and a crosslinking system, in which the volume fraction of filler in the composition is less than or equal to 19%. 2. Conveyor belt according to embodiment 1, in which the ethylene units in the copolymer represent between 50% and 95% by mole of the monomer units of the copolymer. 3. A conveyor belt according to any preceding embodiment, wherein the 1,3-diene is 1,3-butadiene. 4.Conveyor belt according to any one of the preceding embodiments, in which the copolymer contains units of formula (I) or units of formula (II) or units of formula (I) and formula (II). -CH2-CH(CH=CH2)- (II) 5. Conveyor belt according to embodiment 4, in which the molar percentages of the units of formula (I) and of the units of formula (II) in the copolymer, respectively o and p, satisfy the following equation (eq. 1), preferentially to equation (eq. 2), o and p being calculated on the basis of all the monomer units of the copolymer. 0 < o + p ≤ 25 0 < o + p < 20 6. Conveyor belt according to any one of the preceding embodiments, in which the copolymer has a crystallinity of less than 20%, preferably less than 15%, more preferably less than 10%. 7.A conveyor belt according to any preceding embodiment, wherein the ethylene-1,3-diene copolymer is a random copolymer. 8. Conveyor belt according to any one of the preceding embodiments, in which the content of the copolymer in the composition is within a range from 60 to 100 pce, preferably from 80 to 100 pce. 9. A conveyor belt according to any preceding embodiment, wherein the filler comprises carbon black, silica or a mixture thereof. 10. A conveyor belt according to any preceding embodiment, wherein the filler comprises more than 50% by weight, preferably more than 80% by weight of carbon black. 11. Conveyor belt according to any one of the preceding embodiments, in which the filler consists exclusively of carbon black. 12.Conveyor belt according to any one of embodiments 9 to 11, in which the filler comprises more than 50% by weight of at least one carbon black having a BET specific surface area in a range from 60 to 160 m 2 < / g, preferably from 70 to 130 m 2 < / g. 13. Conveyor belt according to any one of the preceding embodiments, in which the load rate is within a range from 10 to less than 100 pce, preferably from 15 to 90 pce. 14. Conveyor belt according to any one of embodiments 1 to 12, in which the load rate is within a range from 10 to less than 49 pce, preferably from 15 to 48 pce, more preferably from 20 to 47 pce. 15.Conveyor belt according to any one of the preceding embodiments, in which the volume fraction of filler in the composition is comprised in a range from 10% to less than 19%, preferably from 10.5% to 18.5%, preferably from 11% to 18%. 16. Conveyor belt according to any one of the preceding embodiments, in which the composition does not comprise any hydrocarbon plasticizing resin or comprises less than 10 pce, preferably less than 5 pce. 17. Conveyor belt according to any one of the preceding embodiments, the composition does not comprise a hydrocarbon plasticizing resin. 18. Conveyor belt according to any one of the preceding embodiments, in which the composition does not comprise a liquid plasticizer at 23°C, or comprises it at a rate less than or equal to 40 pce or less than 30 pce. 19.Conveyor belt according to any one of embodiments 1 to 17, in which the composition comprises a liquid plasticizer at 23°C, preferably at a level within a range from more than 0 to less than 40 pce, preferably from 2 to 30 pce. 20. Conveyor belt according to embodiment 18 or 19, in which the liquid plasticizer at 23°C is chosen from the group consisting of naphthenic oils, paraffinic oils, MES oils, TDAE oils, RAE oils, TRAE oils, SRAE oils, mineral oils, vegetable oils, ether plasticizers, ester plasticizers, phosphate plasticizers, sulfonate plasticizers and mixtures thereof. 21. Conveyor belt according to embodiment 18 or 19, in which the liquid plasticizer at 23°C is chosen from the group consisting of MES oils, TDAE oils, naphthenic oils, vegetable oils and their mixtures. 22.Conveyor belt according to any one of the preceding embodiments, in which the crosslinking system is a vulcanization system based on molecular sulfur and / or based on a sulfur donor agent. 23. Conveyor belt (1) according to any one of the preceding embodiments, comprising a loading layer (2), a reinforcing layer (3) and a driving layer (4), wherein the loading layer (2) is made of a rubber composition as defined in any one of embodiments 1 to 22. V- EXAMPLES V-1 Measures and tests used V-1.1 Determination of the microstructure of elastomers :

[0074] The microstructure of ethylene and butadiene copolymers is determined by 1H NMR analysis, supplemented by 13C NMR analysis when the resolution of 1H NMR spectra does not allow the attribution and quantification of all species. Measurements are carried out using a BRUKER 500MHz NMR spectrometer at frequencies of 500.43 MHz for proton observation and 125.83MHz for carbon observation. For non-soluble elastomers with the ability to swell in a solvent, a 4mm z-grad HRMAS probe is used to observe the proton and carbon in proton-decoupled mode. Spectra are acquired at rotation speeds of 4000Hz to 5000Hz. For measurements on soluble elastomers, a liquid NMR probe is used to observe the proton and carbon in proton-decoupled mode.The preparation of insoluble samples is done in rotors filled with the analyzed material and a deuterated solvent allowing swelling, generally deuterated chloroform (CDCl3). The solvent used must always be deuterated and its chemical nature can be adapted by the skilled person. The quantities of material used are adjusted to obtain spectra with sufficient sensitivity and resolution. Soluble samples are dissolved in a deuterated solvent (approximately 25mg of elastomer in 1mL), generally deuterated chloroform (CDCl3). The solvent or solvent blend used must always be deuterated and its chemical nature can be adapted by the skilled person. In both cases (soluble sample or swollen sample). For proton NMR, a single 30° pulse sequence is used. The spectral window is adjusted to observe all the resonance lines belonging to the analyzed molecules.The number of accumulations is adjusted to obtain a sufficient signal-to-noise ratio for the quantification of each pattern. The recycling time between each pulse is adapted to obtain a quantitative measurement. For carbon NMR, a single 30° pulse sequence is used with proton decoupling only during acquisition to avoid “Nuclear Overhauser” (NOE) effects and remain quantitative. The spectral window is adjusted to observe all the resonance lines belonging to the analyzed molecules. The number of accumulations is adjusted to obtain a sufficient signal-to-noise ratio for the quantification of each pattern. The recycling time between each pulse is adapted to obtain a quantitative measurement. NMR measurements are performed at 25°C. V-1.2 Determination of the macrostructure of polymers by size exclusion chromatography (SEC):

[0075] a) Principle of measurement: Size exclusion chromatography or SEC (Size Exclusion Chromatography) separates macromolecules in solution according to their size through columns filled with a porous gel. The macromolecules are separated according to their hydrodynamic volume, the largest being eluted first. Combined with 3 detectors (3D), a refractometer, a viscometer and a 90° light scattering detector, SEC allows the absolute molar mass distribution of a polymer to be understood. The different number-average absolute molar masses (Mn), weight-average absolute molar masses (Mw) and the dispersity (D = Mw / Mn) can also be calculated. b) Preparation of the polymer: Each sample is solubilized in tetrahydrofuran at a concentration of approximately 1 g / L. Then the solution is filtered through a 0.45µm porosity filter before injection.c) 3D SEC analysis: To determine the number-average molar mass (Mn), and where appropriate the weight-average molar mass (Mw) and the polydispersity index (Ip) of the polymers, the method below is used.

[0076] The number-average molar mass (Mn), weight-average molar mass (Mw) and polydispersity index of the polymer (hereinafter referred to as sample) are determined absolutely by triple detection size exclusion chromatography (SEC). Triple detection size exclusion chromatography has the advantage of measuring average molar masses directly without calibration.

[0077] The refractive index increment dn / dc value of the sample solution is measured online using the peak area detected by the refractometer (RI) of the liquid chromatography equipment. To apply this method, it must be ensured that 100% of the sample mass is injected and eluted through the column. The RI peak area depends on the sample concentration, the RI detector constant and the dn / dc value.

[0078] To determine the average molar masses, the previously prepared and filtered 1g / l solution is used and injected into the chromatographic system. The equipment used is a "WATERS alliance" chromatographic chain. The elution solvent is tetrahydrofuran containing 250 ppm of BHT (2,6-diter-butyl 4-hydroxy toluene), the flow rate is 1 mL.min -1< , the system temperature is 35° C and the analysis time is 60 min. The columns used are a set of three AGILENT columns with the trade name "PL GEL MIXED B LS". The injected volume of the sample solution is 100 µL. The detection system is composed of a Wyatt differential viscometer with the trade name “VISCOSTAR II”, a Wyatt differential refractometer with the trade name “OPTILAB T-REX” with a wavelength of 658 nm, a Wyatt multi-angle static light scattering detector with a wavelength of 658 nm and the trade name “DAWN HELEOS 8+”.

[0079] For the calculation of the number-average molar masses and the polydispersity index, the value of the refractive index increment dn / dc of the sample solution obtained above is integrated. The software for processing the chromatographic data is the “ASTRA de Wyatt” system. V-1.3 Determination of crystallinity

[0080] Crystallinity is measured by measuring the enthalpy of fusion observed in the case of ethylene and 1,3-diene copolymers. This endothermic phenomenon is observed during the analysis of the thermogram of the DSC (Differential Scanning Calorimetry) measurement. The measurement is carried out by back and forth scanning from -150°C to 200°C under an inert atmosphere (helium) with a ramp of 20°C / min.

[0081] The signal corresponding to the endothermic phenomenon (melting) is integrated and the crystallinity rate is the ratio between the measured enthalpy and that of perfectly crystalline polyethylene (290J / g). V-1.4 Abrasion resistance after baking

[0082] Abrasion resistance measurement carried out on a rotating drum at 23°C according to ISO 4649 (2017). The volume of rubber lost during the test is expressed in mm 3< . The lower this volume, the higher the abrasion resistance performance.

[0083] The results are presented on a base of 100 compared to the control. A result greater than 100 indicates a decrease in the value concerned (corresponding to a decrease in the quantity of material torn off), i.e. an improvement in wear resistance. V-1.5 Dynamic properties after curing: Tensile test

[0084] These tensile tests are used to determine the yield stresses and the properties at break. Unless otherwise stated, they are carried out in accordance with French standard NF T 46-002 of September 1988. Processing the tensile records also allows the modulus curve to be plotted as a function of elongation. The modulus used here is the nominal (or apparent) secant modulus measured at first elongation, calculated by referring to the initial section of the specimen.

[0085] The elongation at break (AR%) tests are based on the NF ISO 37 standard of December 2005 on a type H2 dumbbell specimen and are measured at a tensile speed of 500 mm / min. The elongation at break is expressed as a % elongation. The breaking stress is expressed in MPa.

[0086] All these traction measurements are carried out under normal temperature (23±2°C) and hygrometry (50±5% relative humidity) conditions, according to the French standard NF T 40-101 (December 1979).

[0087] The results are presented on a base of 100 compared to the control. A result greater than 100 indicates an increase in the value concerned, i.e. an improvement in the elongation at break. V-1.6 Resistance to fatigue crack propagation after curing (DeMattia Fatigue)

[0088] DeMattia fatigue resistance was determined using the “crack propagation” method according to French standard ISO 132.

[0089] The data retrieved are the number of cycles required for the notch to elongate from L0 mm to (L0 + 2) mm, from L0 mm to (L0 + 6) mm, and from L0 mm to (L0 + 10) mm.

[0090] The higher this number of cycles, the better the composition is considered in terms of fatigue resistance. V-2 Synthesis of the copolymer

[0091] In polymer synthesis, all reagents are obtained commercially except for metallocenes. BOMAG butyloctylmagnesium (20% in heptane, C = 0.88 mol.L -1< ) ​​is obtained from Chemtura and is stored in a Schlenk tube under an inert atmosphere. Ethylene, N35 grade, is obtained from Air Liquide and is used without prior purification.

[0092] The copolymer of ethylene and 1,3-butadiene: elastomer E1 (in accordance with the invention) is synthesized according to the procedure described below.

[0093] In a reactor containing methylcyclohexane at 80°C, as well as ethylene (Et) and butadiene (Bd) in the proportions indicated in Table 1, butyloctylmagnesium (BOMAG) is added to neutralize the impurities in the reactor, then the catalytic system (see Table 1). At this point, the reaction temperature is regulated at 80°C and the polymerization reaction starts. The polymerization reaction proceeds at a constant pressure of 8 bar. The reactor is supplied throughout the polymerization with ethylene and butadiene (Bd) in the proportions defined in Table 1. The polymerization reaction is stopped by cooling, degassing the reactor and adding ethanol. An antioxidant is added to the polymer solution. The copolymer is recovered by drying in a vacuum oven to constant mass. The catalytic system is a preformed catalytic system.It is prepared in methylcyclohexane from a metallocene, [Me 2 SiFlu 2 Nd(µ-BH 4 ) 2 Li(THF)], a co-catalyst, butyloctylmagnesium (BOMAG), and a preformation monomer, 1,3-butadiene, in the contents indicated in Table 1. It is prepared according to a preparation method in accordance with paragraph II.1 of patent application WO 2017 / 093654 A1.

[0094] The microstructure of copolymer E1 and its properties are shown in Tables 2 and 3. For the microstructure, Table 2 shows the molar ratios of ethylene units (Eth), 1,3-butadiene units, 1,2-cyclohexanediyl units (cycle). [Table 1] Synthesis E1 Metallocene concentration (mmol / L) 0,07 Alkylating agent concentration (mmol / L) 0,33 Preformation monomer / Nd metal molar ratio 90 Diet composition (%mol Et / Bd) 80 / 20 [Table 2] Elastomer E1 And (mol%) 79 Bd (mol%) 14 1,2-cyclohexanediyl (mol%) 7 [Table 3] Elastomer E1 Tg (°C) -41 Mn (g / mol) 130 700 V-3 Preparation of compositions

[0095] In the following examples, the rubber compositions were produced as described in point III.7 above. In particular, the “non-productive” phase was carried out in a 3-liter mixer for 5.5 minutes, for an average paddle speed of 60 revolutions per minute until a maximum drop temperature of 160°C was reached. The “productive” phase was carried out in a 3-liter mixer for 3.5 minutes, for an average paddle speed of 30 revolutions per minute, until a maximum drop temperature of 90°C was reached.

[0096] The crosslinking of the composition was carried out at a temperature between 130°C and 200°C, under pressure, in a manner well known to those skilled in the art. V-4 Rubber composition tests

[0097] The examples presented below are intended to compare the performance compromise between resistance to crack propagation and elongation at break as well as the maintenance of elongation at break performance over time, of a composition in accordance with the invention (C1) with two control compositions (T1 and T2).

[0098] Compositions C1, T1 and T2 differ only in the nature of the elastomer matrix. Since the elastomer of composition T1 is extended using a liquid plasticizer, a corresponding level of liquid plasticizer was added to compositions T2 and C1.

[0099] Table 4 shows the compositions tested (in pce), and Table 5 the results obtained. [Table 4] Components T1 T2 C1 EPDM(1) 115 - - SBR(2) - 100 - EBR(3) - - 100 Liquid plasticizer(4) - 15 15 Carbon black(5) 45 45 45 Anti-ozone wax(6) 2,5 2,5 2,5 Antioxidant(7) 3 3 3 TMQ(8) 3 3 3 Stearic acid 1 1 1 ZnO(9) 5 5 5 Sulfur 1,2 1,2 1,2 Accelerator (10) 1,4 1,4 1,4 (1) EPDM extended to 15% by weight of oil (i.e. 4.5 pce in composition T1) having 54% by weight of ethylene, 10% by weight of norbornene marketed under the name “Vistalon 8800” by the company ExxonMobil (2) ESBR “KER1502” from the company Synthos (3) Elastomer E1 prepared above: Elastomer with 79% by mole of ethylene unit, 7% by mole of 1,2-cyclohexanediyl unit, 8% by mole of 1,2 unit, 6% by mole of 1,4 unit (4) Liquid plasticizer “Primol 352” from the company ExxonMobil (5) Carbon black grade N234 according to standard ASTM D-1765 (6) Anti-ozone wax “VARAZON 4959” from the company Sasol Wax (7) N-1,3-dimethylbutyl-N-phenylparaphenylenediamine “Santoflex 6-PPD” from Flexsys (8) 2,2,4-trimethyl-1,2-dihydroquinoline from Flexys (9) Industrial grade zinc oxide from Umicore (10) N-tert-butyl-2-benzothiazyl sulfenamide “Santocure TBBS” from Flexsys [Table 5] Properties T1 T2 C1 Abrasion resistance (base 100) 100 66 107 Fatigue DeMattia L+2 (number of kilocycles) 205 7 000 425 Fatigue DeMattia L+6 (number of kilocycles) 610 22 212 2 189 Fatigue DeMattia L+10 (number of kilocycles) 961 45 885 5 342 Elongation at Break (%) (base 100) 100 151 129 Constraint Break (base 100) 100 61 118

[0100] The results presented in Table 5 above show that the substitution of a prior art EPDM by a copolymer of ethylene and 1,3-diene in accordance with the invention makes it possible to improve both the abrasion resistance, the resistance to crack propagation and the mechanical properties of the rubber composition. The use of a styrene-butadiene copolymer certainly makes it possible to significantly improve the resistance to crack propagation, but this is at the expense of a significant reduction in the abrasion resistance and breaking stress properties.

[0101] Thus, only the composition in accordance with the invention, containing the particular ethylene and 1,3-diene copolymer, makes it possible to improve the aforementioned compromise of properties. This composition also has the advantage of making it possible to use only one elastomer, which makes it possible to simplify the manufacturing process of the composition.

Claims

1. Conveyor belt comprising a rubber composition at least based on more than 50 phr of a copolymer of ethylene and of 1,3-diene, the ethylene units in the copolymer representing more than 50 mol% of the monomer units of the copolymer, on a filler and on a crosslinking system, in which the volume fraction of filler in the composition is less than or equal to 19%.

2. Conveyor belt according to Claim 1, wherein the ethylene units in the copolymer represent between 50 mol% and 95 mol% of the monomer units of the copolymer.

3. Conveyor belt according to Claim 1 or 2, wherein the 1,3-diene is 1,3-butadiene.

4. Conveyor belt according to any one of the preceding claims, wherein the copolymer contains units of formula (I) or units of formula (II) or else units of formula (I) and of formula (II).         -CH2-CH(CH=CH2)-     (II) 5. Conveyor belt according to any one of the preceding claims, wherein the copolymer has a crystallinity of less than 20%, preferably less than 15%, more preferably less than 10%.

6. Conveyor belt according to any one of the preceding claims, wherein the copolymer of ethylene and of 1,3-diene is a random copolymer.

7. Conveyor belt according to any one of the preceding claims, wherein the content of the copolymer in the composition is within a range extending from 60 to 100 phr, preferably from 80 to 100 phr.

8. Conveyor belt according to any one of the preceding claims, wherein the filler comprises carbon black, silica or a mixture thereof.

9. Conveyor belt according to any one of the preceding claims, wherein the filler comprises more than 50% by weight, preferably more than 80% by weight, of carbon black.

10. Conveyor belt according to any one of the preceding claims, wherein the volume fraction of filler in the composition is within a range extending from 10% to less than 19%, preferably from 11% to 18%.

11. Conveyor belt according to any one of the preceding claims, wherein the composition does not comprise any hydrocarbon-based plasticizing resin or comprises less than 10 phr thereof, preferably less than 5 phr thereof.

12. Conveyor belt according to any one of the preceding claims, wherein the composition comprises a plasticizer that is liquid at 23°C, preferably at a content within a range extending from more than 0 to less than 40 phr, preferably from 2 to 30 phr.

13. Conveyor belt according to Claim 12, wherein the plasticizer that is liquid at 23°C is chosen from the group consisting of naphthenic oils, paraffinic oils, MES oils, TDAE oils, RAE oils, TRAE oils, SRAE oils, mineral oils, vegetable oils, ether plasticizers, ester plasticizers, phosphate plasticizers, sulfonate plasticizers and mixtures thereof.

14. Conveyor belt according to any one of the preceding claims, wherein the crosslinking system is a vulcanization system based on molecular sulfur and / or based on a sulfur-donating agent.

15. Conveyor belt (1) according to any one of the preceding claims, comprising a loading layer (2), a reinforcement layer (3) and a drive layer (4), in which the loading layer (2) consists of a rubber composition as defined in any one of Claims 1 to 14.