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    • 专利摘要:
    The present invention relates to an aircraft tire whose tread comprises a rubber composition based on at least a first diene elastomer, a reinforcing filler and a crosslinking system, which first diene elastomer is a terpolymer of ethylene, an α-olefin and a nonconjugated diene. Such a tire has a greatly improved landing performance, especially with respect to the very high speed wear resistance.
    公开号:FR3024155A1
    申请号:FR1457052
    申请日:2014-07-22
    公开日:2016-01-29
    发明作者:Da Silva José-Carlos Araujo；Aurelie Triguel
    申请人:Michelin Recherche et Technique SA Switzerland ；Compagnie Generale des Etablissements Michelin SCA；Michelin Recherche et Technique SA France；
    IPC主号:
    专利说明:

    [0001] The present invention relates to tires for equipping aircraft.
    [0002] As is known, an aircraft tire must withstand high pressure, load and speed conditions. In addition it must also meet the requirements of resistance to wear and endurance. Endurance means the ability of the tire to withstand over time the cyclic stresses to which it is subjected. When the tread of an aircraft tire is worn, marking the end of a first life of use, the tire is retreaded, that is to say that the worn tread is replaced by a new tread to allow a second life of use. Improved wear resistance allows for more landings per life of use. An improved endurance allows to increase the number of lives of use of the same tire. It is known to use, in aircraft tire treads, rubber compositions based on natural rubber and carbon black, these two main elements making it possible to obtain compositions having properties compatible with the conditions of the invention. use of an airplane tire. In addition to these main elements, these compositions comprise the usual additives of this type of compositions such as a vulcanization system and protective agents. Such aircraft tire tread compositions have been used for many years and have mechanical properties to withstand the very particular wear conditions of aircraft tires. Indeed, these tires are subject to very large temperature and speed variations, especially at landing where they must go from a zero speed to a very high speed, causing considerable heating and wear.
    [0003] It is therefore always interesting for aircraft tire manufacturers to find more efficient and more resistant solutions, in particular more resistant to the extreme wear conditions caused by landing aircraft. A study (SK Clark "Touchdown Dynamics", Precision Measurement Company, Ann Arbor, Mt. NASA, Langley Research Center, Computational Modeling of Tires, pages 9-19, published August 1995) described the stresses on airframe tires in Canada. the landing and proposed a method of evaluating the performance of the aircraft tires during these requests. In their research, the Applicants have found that a particular composition of aircraft tire treads can improve the properties of aircraft tires, particularly for the landing phase of these tires. Accordingly, the invention relates to an aircraft tire whose tread comprises a rubber composition based on at least a first diene elastomer, a reinforcing filler and a crosslinking system, which first elastomer diene is a terpolymer of ethylene, an α-olefin and a nonconjugated diene. I. DETAILED DESCRIPTION OF THE INVENTION By the term "base-based" composition is meant a composition comprising the mixture and / or the reaction product of the various constituents used, some of these basic constituents being capable of , or intended to react with each other, at least in part, during the various phases of manufacture of the composition, in particular during its crosslinking or vulcanization.
    [0004] By the term "part by weight per hundred parts by weight of elastomer" (or phr) is meant for the purposes of the present invention, the part, by weight per hundred parts of elastomer. In the present description, unless expressly indicated otherwise, all the percentages (%) indicated are percentages (%) by mass. On the other hand, any range of values designated by the expression "between a and h" represents the range of values from more than a to less than b (i.e. terminals a and b excluded) while any range of values designated by the expression "from a to h" means the range from a to b (i.e., including the strict limits a and b).
    [0005] Generally speaking, a tire comprises a tread intended to come into contact with the ground via a running surface, and connected via two sidewalls to two beads intended to provide a link between the tire and the rim on which it is mounted.
    [0006] In the following, the circumferential, axial and radial directions respectively designate a direction tangent to the running surface of the tire in the direction of rotation of the tire, a direction parallel to the axis of rotation of the tire and a direction perpendicular to the tire. axis of rotation of the tire. By "radially inner, respectively radially outer" is meant "closer or further away from the axis of rotation of the tire". By "axially inner, respectively axially outer" is meant "closer or more distant from the equatorial plane of the tire", the equatorial plane of the tire being the plane passing through the middle of the running surface of the tire and perpendicular to the tire. rotation axis of the tire. A radial tire more particularly comprises a reinforcing reinforcement, comprising a crown reinforcement, radially inner to the tread, and a carcass reinforcement, radially inner to the crown reinforcement.
    [0007] The carcass reinforcement of an aircraft tire generally comprises a plurality of carcass layers extending between the two beads and distributed between a first and a second family. The first family consists of carcass layers, wound in each bead from the inside to the outside of the tire, around a circumferential reinforcing element, called a bead wire, to form a reversal of which the end is generally radially external to the most radially outer point of the rod. The upturn is the carcass layer portion between the most radially inner point of the carcass layer and its end. The carcass layers of the first family are the carcass layers closest to the inner cavity of the tire and therefore the most axially inner, in the flanks. The second family consists of carcass layers extending, in each bead, from the outside to the inside of the tire, to a generally radially inner end at the most radially outer point of the bead wire. The carcass layers of the second family are the carcass layers closest to the outer surface of the tire and therefore the most axially outer, in the flanks.
    [0008] Usually, the carcass layers of the second family are positioned, throughout their entire length, outside the carcass layers of the first family, that is to say they envelop, in particular, the overturnings of the carcass layers of the first family. Each carcass layer of the first and second families consists of reinforcing members parallel to each other, making an angle of between 80 ° and 100 ° with the circumferential direction. The reinforcing elements of the carcass layers are most often cables consisting of textile filament yarns, preferably of aliphatic polyamide or aromatic polyamide, and characterized by their mechanical properties in extension. The textile reinforcing elements are pulled over an initial length of 400 mm at a nominal speed of 200 mm / min. All results are an average of 10 measurements. In use, an aircraft tire is subjected to a combination of load and pressure inducing a high bending rate, typically greater than 30% (e.g. 32% or 35%). The bending rate of a tire is, by definition, its radial deformation, or its radial height variation, when it changes from an uncharged inflated state to a statically loaded inflated state in a radial state. pressure and load conditions as defined, for example, by the standard of the Tire and Rim Association or TRA. It is defined by the ratio of the variation of the radial height of the tire on the half of the difference between the outside diameter of the tire, measured statically in an unfilled state inflated to the reference pressure, and the maximum diameter of the tire. rim, measured on the rim flange. The TRA standard defines in particular the crushing of an aircraft tire by its crushed radius, that is to say by the distance between the axis of the wheel of the tire and the plane of the ground with which the tire is in contact under the conditions of pressure and reference load. An aircraft tire is also subjected to a high inflation pressure, typically greater than 9 bar. This high pressure level involves a large number of carcass layers, since the carcass reinforcement is dimensioned to provide the resistance of the tire at this pressure level with a high safety factor. By way of example, the carcass reinforcement of a tire whose working pressure, as recommended by the TRA standard, is equal to 15 bars, must be dimensioned to withstand a pressure equal to 60 bars, in the assumption of a safety factor of 4. With textile materials commonly used for reinforcing elements, such as aliphatic polyamides or aromatic polyamides, the carcass reinforcement may, for example, comprise at least 5 carcass layers. In use, the mechanical stresses of rolling induce bending cycles in the beads of the tire, which roll up on the rim flanges. In particular, in the carcass layer portions in the rim flexion zone, these bending cycles 25 produce curvature variations combined with variations in elongation of the carcass layer reinforcing elements. These variations in elongation or deformations, in particular in the most axially outer carcass layers, may have negative minimum values, corresponding to compression.
    [0009] This compression is likely to induce a fatigue failure of the reinforcing elements and therefore premature degradation of the tire. Thus, the aircraft tire according to the invention is preferably an aircraft tire which is subjected during its use to a combination of load and pressure inducing a bending rate greater than 30. Similarly, the aircraft tire according to the invention The invention is preferably an air tire comprising in addition to the tread, an internal structure comprising a plurality of carcass layers extending between the two beads and distributed between a first and a second family, the first family consisting of by carcass layers, wrapping, in each bead, from the inside to the outside of the tire and the second family being constituted by carcass layers extending in each bead, outside to the inside of the tire.
    [0010] The tread composition of the aircraft tires according to the invention comprises a terpolymer of ethylene, an α-olefin and a nonconjugated diene. The α-olefin may be a mixture of alpha olefins. The α-olefin generally comprises 3 to 16 carbon atoms. Suitable α-olefins are, for example, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and 1-dodecene. Advantageously, the α-olefin is propylene, in which case the terpolymer is commonly called an EPDM (in English "EPDM rubber"). The non-conjugated diene generally comprises 6 to 12 carbon atoms. As non-conjugated diene, there may be mentioned dicyclopentadiene, 1,4-hexadiene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 1,5-cyclooctadiene. Advantageously, the non-conjugated diene is 5-ethylidene-2-norbornene. According to one embodiment of the invention, the first diene elastomer has at least one of the following characteristics, preferably all: the ethylene units represent between 20 and 90%, preferably between 30 and 70% by weight of the first elastomer diene, the α-olefin units represent between 10 and 80%, preferably from 15 to 70% by weight of the first diene elastomer, the non-conjugated diene units represent between 0.5 and 20% by weight of the first diene elastomer. The first diene elastomer preferably has a weight average molecular weight (Mw) of at least 60,000 g / mol and at most 1,500,000 g / mol, preferably at least 100,000 g / mol and not more than 700 000 g / mol. The values of Mw are measured according to the SEC method described in paragraph 11.1-a). It is understood that the first diene elastomer may consist of a mixture of terpolymers of ethylene, α-olefin and non-conjugated diene which differ from each other by their macrostructure or their microstructure, in particular by the respective mass ratio. ethylene, α-olefin and non-conjugated diene units. According to one embodiment of the invention, the first diene elastomer is the only elastomer of the rubber composition.
    [0011] According to a particular embodiment of the invention, the rubber composition further comprises a second elastomer, preferably diene, that is to say comprising diene monomeric units. When the rubber composition comprises a second elastomer, it preferably comprises more than 50 phr, more preferably more than 60 phr of the first diene elastomer. The second elastomer may be a "substantially unsaturated" or "essentially saturated" diene elastomer. The term "essentially unsaturated" is generally understood to mean a diene elastomer derived at least in part from conjugated diene monomers having a level of units or units 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 of the EPDM type do not fall within the above definition and may in particular be described as "essentially saturated" diene elastomers ( low or very low diene origin, always less than 15%).
    [0012] In the category of "essentially unsaturated" diene elastomers, the term "highly unsaturated" diene elastomer is particularly understood to mean a diene elastomer having a diene origin ratio (conjugated dienes) of greater than 50%. Given these definitions, the second diene elastomer that may be used in the compositions in accordance with the invention may be: (a) - any homopolymer of a conjugated diene monomer, especially any homopolymer obtained by polymerization of a diene monomer conjugate having from 4 to 12 carbon atoms; (b) - any copolymer obtained by copolymerization of one or more conjugated dienes with each other or with one or more vinyl aromatic compounds having 8 to 20 carbon atoms; (c) - a ternary copolymer obtained by copolymerization of ethylene, an α-olefin having 3 to 6 carbon atoms with a non-conjugated diene monomer having from 6 to 12 carbon atoms, for example elastomers obtained from ethylene, propylene with a non-conjugated diene monomer of the aforementioned type such as in particular 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene; (d) an unsaturated olefinic copolymer whose chain comprises at least olefinic monomer units, ie units resulting from the insertion of at least one α-olefin or ethylene, and diene monomeric units derived from of at least one conjugated diene.
    [0013] The second elastomer is preferably a diene elastomer selected from the group of "highly unsaturated" diene elastomers consisting of polybutadienes, polyisoprenes, butadiene copolymers, isoprene copolymers and mixtures of these elastomers. Polyisoprenes can be synthetic (IR) or natural rubber 40 (NR). It is understood that the second diene elastomer may consist of a mixture of diene elastomers which differ from each other by their microstructure, by their macrostructure or by the presence of a function, by the nature or the position of the latter on the elastomeric chain. The reinforcing filler, known for its ability to reinforce a rubber composition which can be used for the manufacture of tires, can be a carbon black, a reinforcing inorganic filler such as silica with which a coupling agent is associated in a known manner, or a mixture of these two types of filler. Such a reinforcing filler typically consists of nanoparticles whose mean (mass) size is less than one micrometer, generally less than 500 nm, most often between 20 and 200 nm, in particular and more preferably between 20 and 150 nm. . The carbon black has a BET surface area of preferably at least 90 m 2 / g, more preferably at least 100 m 2 / g. As such are suitable black conventionally used in tires or their treads (so-called pneumatic grade black). Among these, more particularly include reinforcing carbon blacks of the series 100, 200, 300 (ASTM grade), such as blacks N115, N134, N234, N375. The carbon blacks can be used in the isolated state, as commercially available, or in any other form, for example as a carrier for some of the rubber additives used. The BET surface area of the carbon blacks is measured according to the D6556-10 standard [multipoint method (at least 5 points) - gas: nitrogen - relative pressure range P / PO: 0.1 to 0.3].
    [0014] According to one embodiment of the invention, the reinforcing filler also comprises a reinforcing inorganic filler. "Reinforcing inorganic filler" means any inorganic or mineral filler, irrespective of its color and origin (natural or synthetic), also called "white" filler, "clear" filler or even "non-black" filler. As opposed to carbon black, capable of reinforcing on its own, without any means other than an intermediate coupling agent, a rubber composition intended for the manufacture of pneumatic tires, in other words able to replace, in its reinforcement function, a conventional carbon black of pneumatic grade; such a filler is generally characterized, in known manner, by the presence of hydroxyl groups (-OH) on its surface.
    [0015] Suitable reinforcing inorganic fillers are mineral fillers of the siliceous type, preferentially silica (5iO 2). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or fumed silica having a BET surface and a CTAB specific surface area both less than 40 450 m2 / g, preferably from 30 to 400 m2 / g, especially between 60 and 300 m2 / g. P10-3400 3024155 8 The physical state under which the reinforcing inorganic filler is present is indifferent, whether in the form of powder, microbeads, granules or beads. Of course, the term "reinforcing inorganic filler" is also understood to mean mixtures of different reinforcing inorganic fillers, in particular of highly dispersible silicas as described above. In the present description, with regard to silica, the BET surface area is determined in a known manner by gas adsorption using the method of Brunauer-Emmett-Teller described in "The Journal of the American Chemical Society" Flight . 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 is the external surface determined according to the French standard NF T 45-007 of November 1987 (method B).
    [0016] In order to couple the reinforcing inorganic filler to the diene elastomer, an at least bifunctional coupling agent (or bonding agent) is well known to provide a sufficient chemical and / or physical connection between the filler. inorganic (surface of its particles) and the diene elastomer. In particular, organosilanes or at least bifunctional polyorganosiloxanes are used.
    [0017] In particular, but not limited to the following definition, polysulfide silanes having the following general formula (I): (I) Z - A - Sx - A - Z, wherein: - x is an integer from 2 to 8 (preferably from 2 to 5); the symbols A, identical or different, represent a divalent hydrocarbon radical (preferably a C1-C18 alkylene group or a C6-C12 arylene group, more particularly a C1-C10 alkylene, especially C1-C4 alkylene, in particular propylene); The symbols Z, which may be identical or different, correspond to one of the following three formulas: ## STR1 ## in which: the radicals Ft 1, substituted or unsubstituted, identical or different from each other; represent a C 1 -C 18 alkyl, C 5 -C 18 cycloalkyl or C 6 -C 18 aryl group (preferably C 1 -C 6 alkyl, cyclohexyl or phenyl groups, especially C 1 -C 4 alkyl groups, more particularly methyl and / or ethyl). The radicals R2, substituted or unsubstituted, which are identical to or different from one another, represent a C1-C18 alkoxyl or a C5-C18 cycloalkoxyl group (preferably a group chosen from C1-C8 alkoxyls and cycloalkoxyls in the C5-C18 alkoxy group); C5-C8, more preferably still a group selected from C1-C4 alkoxyls, in particular methoxyl and ethoxyl).
    [0018] As examples of polysulfide silanes, polysulfides (especially disulfides, trisulphides or tetrasulfides) of bis- (C 1 -C 4 alkoxy) -alkyl (C 1 -C 4) silylalkyl (C 1 -C 4) are particularly suitable. for example polysulfides of bis (3-trimethoxysilylpropyl) or bis (3-triethoxysilylpropyl). Among these compounds, bis (3-triethoxysilylpropyl) tetrasulfide, abbreviated to TESPT, of formula [(C2H50) 3Si (CH2) 3S2] 2 or bis (triethoxysilylpropyl) disulfide, abbreviated to TESPD, is especially used. of formula [(C2H50) 3Si (CH2) 3S] 2. By way of examples of other organosilanes, mention may be made, for example, of silanes bearing at least one thiol function (-SH) (called mercaptosilanes) and / or of at least one blocked thiol group, as described, for example, in patents or patent applications US 6,849,754, WO 99/09036, WO 2006/023815, WO 2007/098080, WO 2010/072685 and WO 2008/055986. The content of coupling agent is advantageously less than 12 phr, it being understood that it is generally desirable to use as little as possible. Typically the level of coupling agent is 0.5% to 15% by weight based on the amount of inorganic filler. Its level is preferably between 0.5 and 9 phr, more preferably in a range from 3 to 9 phr. This level is easily adjusted by those skilled in the art according to the level of inorganic filler used in the composition. According to a preferred embodiment of the invention, the reinforcing filler consists of 100% by weight of carbon black. According to another embodiment of the invention, the level of reinforcing filler is in a range from 20 to 70 phr, preferably from 25 to 50 phr.
    [0019] The crosslinking system may be based on either sulfur or sulfur and / or peroxide donors and / or bismaleimides. The crosslinking system is preferably a vulcanization system, that is to say a system based on sulfur (or a sulfur-donor agent) and a primary vulcanization accelerator. To this basic vulcanization system are added, incorporated during the first non-productive phase and / or during the production phase as described later, various known secondary accelerators or vulcanization activators such as zinc, stearic acid or equivalent compounds, guanidine derivatives (in particular diphenylguanidine), or known vulcanization retarders. P10-3400 3024155 Sulfur is used at a preferential rate of between 0.5 and 12 phr, in particular between 1 and 10 phr. The primary vulcanization accelerator is used at a preferred level of between 0.5 and 10 phr, more preferably between 0.5 and 5.0 phr.
    [0020] The rubber composition may also comprise all or part of the usual additives usually used in elastomer compositions intended to constitute treads, such as, for example, plasticizers, pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, anti-oxidants, anti-fatigue agents.
    [0021] According to a preferred embodiment of the invention, the rubber composition contains from 0 to 20 phr of a liquid plasticizer, preferably it is devoid of any liquid plasticizer.
    [0022] A plasticizer is considered liquid when, at 23 ° C, it has the capacity to eventually take the shape of its container, this definition being given in contrast to plasticizing resins which are inherently solid at room temperature. As liquid plasticizer, there may be mentioned vegetable oils, mineral oils, plasticizers ethers, esters, phosphates, sulfonates and mixtures thereof.
    [0023] The rubber composition according to the invention can be manufactured in suitable mixers, using two successive preparation phases according to a general procedure well known to those skilled in the art: a first phase of work or thermo-mechanical mixing (sometimes qualified non-productive phase) at a high temperature, up to a maximum temperature of between 130 ° C. and 200 ° C., preferably between 145 ° C. and 185 ° C., followed by a second phase of mechanical work ( sometimes referred to as a "productive" phase) at a lower temperature, typically below 120 ° C, for example between 60 ° C and 100 ° C, a finishing phase during which the chemical crosslinking agent is incorporated, in particular the vulcanization system.
    [0024] The rubber composition according to the invention can be either in the green state (before crosslinking or vulcanization) or in the fired state (after crosslinking or vulcanization), can be a semi-finished product that can be used in a tire, in particular in a tire tread.
    [0025] The aforementioned features of the present invention, as well as others, will be better understood on reading the following description of several exemplary embodiments of the invention, given by way of illustration and not limitation.
    [0026] 40 II. EXAMPLES OF EMBODIMENT OF THE INVENTION II.1-Measurements and Tests Used: 11.1-a) Size Exclusion Chromatography Size Exclusion Chromatography (SEC) is used. The SEC allows the macromolecules to be separated in solution according to their size through columns filled with a porous gel. The macromolecules are separated according to their hydrodynamic volume, the larger ones being eluted first. Without being an absolute method, the SEC allows to apprehend the distribution of the molar masses of a polymer. From commercial standard products, the various average molar masses (Mn) and weight (Mw) can be determined and the polymolecularity index (Ip = Mw / Mn) calculated via a calibration called MOORE. Preparation of the polymer: There is no particular treatment of the polymer sample before analysis. This is simply solubilized in (tetrahydrofuran + 1% vol diisopropylamine + 1% vol triethylamine + 1% vol distilled water) or in chloroform at a concentration of about 1 g / I . The solution is then filtered through a 0.45 μm porosity filter before injection. SEC analysis: The equipment used is a "WATERS alliance" chromatograph. The elution solvent is tetrahydrofuran + 1% vol. of diisopropylamine + 1% vol. triethylamine or chloroform depending on the solvent used for dissolving the polymer. The flow rate is 0.7 ml / min, the system temperature 35 ° C and the analysis time 90 min. A set of four WATERS columns in series, trade names "STYRAGEL HMW7", "STYRAGEL HMW6E" and two "STYRAGEL HT6E" are used. The injected volume of the solution of the polymer sample is 100 μl. The detector is a WATERS 2410 differential refractometer and the chromatographic data exploitation software is the WATERS EMPOWER system. The average molar masses calculated relate to a calibration curve made from commercial standard polystyrene "PSS READY CAL-KIT". 11.1-b) Loss of mass This test makes it possible to determine the loss of mass of an aircraft tire tread composition sample when it is subjected to an abrasion test on a high-speed abrasive tester. The high speed abrasion test is performed according to the principle described in SK Clark's "Touchdown Dynamics" article, Precision Measurement Company, Ann Arbor, NASA Mt., 35 Langley Research Center, Computational Modeling of Tires pages 9-19 published in August 1995. The tread material rubs on a surface such as a Norton Vulcan A30S-BF42. The linear velocity during contact is 70 m / s with an average contact pressure of 15 to 20 bar. The device is designed to scrub until a power of 10 to 20 MJ / m2 of contact area is exhausted. P10-3400 3024155 12 The elements of the constant energy tribometry device according to the S.K. Clark article mentioned above are a motor, a clutch, a turntable and a sample holder. The performance is evaluated on the basis of mass loss according to the following formula: Mass loss performance = loss of control mass / loss of mass sample. The results are expressed in base 100. A performance for the sample greater than 100 is considered better than the control. 11.1-c) Rheometry: The measurements are carried out at 150 ° C. with an oscillating chamber rheometer according to DIN 53529 - Part 3 (June 1983). The evolution of the rheometric torque, ACouple (in dN.m), as a function of time describes the evolution of the stiffening of the composition as a result of the vulcanization reaction. The measurements are processed according to DIN 53529 - Part 2 (March 1983): T0 is the induction time, that is to say the time required for the beginning of the vulcanization reaction; Ta (for example T99) is the time necessary to reach a conversion of a%, that is to say a% (for example 99%) of the difference between the minimum and maximum couples. The conversion rate constant denoted by K (expressed in min-1), of order 1, calculated between 30% and 80% conversion, which makes it possible to evaluate the kinetics of vulcanization, is also measured. 11.1-d) Tensile tests: These tensile tests make it possible to determine the modulus of elasticity and the properties at break and are based on the NF ISO 37 standard of December 2005 on a dumbbell test tube type 2. Elongation The rupture thus measured at 23 ° C. is expressed as% elongation. II.2-Preparation of the compositions and their properties for firing: The compositions, in the species Cl to C24, T1 and T2 whose formulation in phr appears in Tables 1, 2, 4 to 7 are prepared in the following manner: In an internal mixer (final filling ratio: about 70% by volume), the initial batch temperature of which is approximately 80 ° C., the diene elastomers, the reinforcing fillers and the various other ingredients are introduced successively. the exception of the vulcanization system. Thermomechanical work (non-productive phase) is then carried out in one step, which lasts a total of about 3 to 4 minutes, until a maximum "falling" temperature of 165 ° C. is reached. The mixture thus obtained is recovered, cooled and then sulfur and a sulphonamide type accelerator are incorporated on a mixer (homo-finisher) at 70 ° C., mixing the whole (productive phase) for a suitable time (for example a dozen minutes). The compositions thus obtained are then calendered either in the form of plates 40 (thickness 2 to 3 mm) or thin sheets of rubber for the measurement of their physical or mechanical properties, or extruded in the form of a strip. Pneumatic tire rolling. T1 and T2 are two control compositions. T1 corresponds to the composition of an aircraft rolling strip conventionally used by those skilled in the art to manufacture an air tire tread; it is based on natural rubber. T2 also contains natural rubber, but the filler rate and the vulcanization system differ from the T1 control composition.
    [0027] Tests C1 to C24 are in accordance with the invention, since the compositions corresponding to these tests contain an EPDM, possibly a highly unsaturated diene elastomer (different rates illustrated), a reinforcing filler (carbon black or silica at various illustrated rates) and a crosslinking system. They differ in the microstructure or macrostructure of the EPDM, the respective level of EPDM and diene elastomer 15 highly unsaturated, by the nature and the rate of reinforcing filler, silica or carbon black, or the crosslinking system, sulfur or peroxide. Test 1: This test is intended to show the influence of the EPDM level in the rubber composition on the firing properties of the rubber composition. Table 1 T2 Cl C2 C3 C4 C5 NR (1) 100 - 10 20 40 60 EPDM 1 (2) - 100 90 80 60 40 Carbon black (3) Antioxidant (4) 1.5 1, 5 1.5 1.5 1.5 1.5 Stearic Acid (5) 2.5 2.5 2.5 2.5 2.5 2.5 Zinc Oxide (6) 3 3 3 3 3 3 Accelerator (5) 7) 2 2 2 2 2 2 Sulfur 0.8 0.8 0.8 0.8 0.8 0.8 Elongation Rupture at 23 ° C (%) 528 634 664 658 560 465 Performance mass loss (%) 100 173 146 132 123 119 (1) Natural rubber (2) EPDM Nordel IP 4570 from Dow 25 (3) carbon black N234 grade according to ASTM D-1765 (4) N-1,3-dimethylbutyl-N Phenylparaphenylenediamine "Santoflex 6-PPD" from Flexsys (5) Stearin "Pristerene 4931" from Uniqema (6) Industrial grade zinc oxide from Umicore P10-3400 3024155 14 (7) N-cyclohexyl-2 The result of this test shows that the loss of mass performance is always improved compared to the control T2. On the other hand, below an EPDM level of 50 phr, deposition of the mechanical properties is observed, with regard to the level of the elongation rupture. Thus, the invention has the advantage of allowing a better mass loss performance, representative of a better wear resistance during the landing phase of the aircraft. It is observed that the use of more than 50 phr of EPDM in the rubber composition leads to a better compromise of performance between the loss of mass and the elongation fracture. Test 2: This test aims to show the influence of the macrostructure of the EPDM and its microstructure. In particular, the influence of ethylene unit level in EPDM as well as the influence of non-conjugated diene units has been studied. The characteristics of the EPDMs used in this test are shown in Table 3, the monomer unit rates are mass ratios per 100 g of EPDM. Table 2 T1 Cl C6 C7 C8 C9 NR (1) 100 - EPDM 1 (2) - 100 - EPDM 2 (3) - 100 - EPDM 3 (4) - 100 - EPDM 4 (5) EPDM 5 (6) ) - 100 Carbon black (7) 47.5 30 30 30 30 30 Antioxidant (8) 1.5 1.5 1.5 1.5 1.5 1.5 Stearic acid (9) 2.5 2.5 2.5 2.5 2.5 2.5 Zinc Oxide (10) 3 3 3 3 3 3 Accelerator (11) 0.8 2 2 2 2 2 Sulfur 1.5 0.8 0.8 0.8 0 , 8 0.8 Performance mass loss (%) 100 195 197 173 130 183 20 (1) Natural rubber (2) EPDM "Nordel IP 4570" from Dow (3) EPDM "Keltan 9950" from Lanxess ( 4) EPDM "9090M" from the Mitsui Company (5) EPDM "Keltan 4460D" from the Lanxess Company 25 (6) EPDM "Nordel IP 4770R" from the Dow Company (7) N234 grade carbon black according to the ASTM D standard (8) N-1,3-dimethylbutyl-N-phenylparaphenylenediamine "Santoflex 6-PPD" from Flexsys (9) Stearin "Pristerene 4931" from Uniqema (10) Zinc oxide industrial grade of Umicore 5 (11) N-cyclohexyl-2-benzothiazyl sulfenamide "Santocure CBS" from Flexsys Table 3 EPDM Ethylene Nature Diene Mw * diene (g / mol) EPDM 1 50 ENB 4.9 390000 EPDM 2 48 ENB 9 498000 EPDM 3 41 ENB 14 442000 EPDM 4 58 DCPD 4.5 230000 EPDM 5 70 ENB 4.9 NM ** ENB: 5-Ethylidene-2-norbornene DCPD: dicyclopentadiene 10 * SEC method described in Section 11.1-a) ** Not measured. The result of this test shows that the mass loss performance is always improved compared to the control.
    [0028] At substantially equal ethylene level, the effect of the nature of the nonconjugated diene was studied. The performance of the corresponding materials, that is to say compositions C1 and C8 according to the invention, remains higher than the control. It is observed that the EPDMs whose nonconjugated diene is the ENB give the best results. At a substantially equal ethylene level, the increase in the level of non-conjugated diene unit in the EPDM induces a very weak effect on the mass loss performance, with regard to the performances of the compositions Cl, C6 and C7. In fact, a 5% non-conjugated diene unit rate leads to the same mass loss performance as a 9% rate whereas a 14% rate only leads to a very slight decrease in the mass loss performance. Finally, the increase in the ethylene unit level in the EPDM has a very small effect on the mass loss performance, with respect to the performances of the compositions Cl, C7 and C9. The performance is always improved compared to the witness. Test 3: This test aims to show the influence of the crosslinking system.
    [0029] Table 4 T1 Cl C10 C11 C12 NR (1) 100 - EPDM 1 (2) - 100 100 100 100 Carbon black (3) 47.5 30 30 30 30 Antioxidant (4) 1.5 1 , 1.5 1.5 1.5 Stearic acid (5) 2.5 2.5 2.5 2.5 2.5 Zinc oxide (6) 3 3 3 3 3 Accelerator (7) 0.8 2 0.8 2 2 Peroxide (8) - 3.2 Ultra Accelerator (9) - 1.5 - Sulfur 1.5 0.8 1.5 1 1 Cooking T99 (min) 15 36 80 18 51 Cooking K (min. 1) 0.56 0.15 0.07 0.30 0.10 Performance mass loss (%) 100 195 189 216 210 (1) Natural rubber (2) EPDM "Nordel IP 4570" from the Dow Company (3) Carbon black of grade N234 according to ASTM D-1765 5 (4) N-1,3-dimethylbutyl-N-phenylparapenylenediamine "Santoflex 6-PPD" from Flexsys (5) Stearin "Pristerene 4931" from Uniqema (6) Industrial grade zinc oxide from the company Umicore (7) N-cyclohexyl-2-benzothiazyl sulfenamide "Santocure CBS" from the company Flexsys 10 (8) Dicumyl peroxide "Lupérox" from the company Archema (9) "Dibenzyld The result of this test shows that the mass loss performance is always improved compared to the control. Various vulcanization systems can be used, which makes it possible to adjust the T99, for example, to approach the cooking times of a control mixture, and not to be penalized in terms of industrial productivity. Test 4: This test is intended to show the influence of the level of liquid plasticizer in the rubber composition.
    [0030] P10-3400 3024155 17 Table 5 T2 Cl C13 C14 NR (1) 100 - - - EPDM (2) - 100 100 100 Plasticizer (3) - - 9 20 Carbon Black (4) 30 30 32.5 35.7 Antioxidant (5) 1.5 1.5 1.5 1.5 Stearic Acid (6) 2.5 2.5 2.5 2.5 Zinc Oxide (7) 3 3 3 3 Accelerator (8) 2 2 2 2 Sulfur 0.8 0.8 0.8 0.8 Performance mass loss (%) 100 173 164 155 Table 6 T1 C15 C16 C17 NR (1) 100 - - - EPDM (2) - 100 100 100 Plasticizer (3) ) Carbon black (4) 47.5 47.5 51.5 56.5 Antioxidant (5) 1.5 1.5 1.5 1.5 Stearic acid (6) 2.5 2.5 2, 5 2.5 Zinc Oxide (7) 3 3 3 3 Accelerator (8) 0.8 2 2 2 Sulfur 1.5 0.8 0.8 0.8 Performance mass loss (%) 100 149 143 136 5 ( 1) Natural rubber (2) EPDM "Nordel IP 4570" from the Dow Company (3) Tudalen oil 1968 from Klaus Dahleke (4) Carbon black N234 grade according to ASTM D-1765 (5) N-1 3-dimethylbutyl-N-phenylparapenylenediamine "Santoflex 6-PPD" from Flexsys (6) Stearin "Pristerene 4931" from the company (7) Industrial Grade Zinc Oxide from Umicore (8) N-cyclohexyl-2-benzothiazyl sulfenamide "Santocure CBS" Company of Flexsys The compositions Cl, C13 and C14 of the invention have a increasing dilution, as well as increasing charge rate. They have the characteristic of presenting the same volume fraction of charge as the control composition T2. The same applies to the compositions P10-3400 3024155 18 C15, C16 and C17, which have the same volume fraction of filler as the composition T1. The loss of mass performance decreases with the increase of the dilution rate but remains always higher than the control. However, those skilled in the art understand that beyond 20 phr of plasticizer, rigidity is penalized. Therefore a liquid plasticizer level of less than or equal to 20 phr is preferred. Test 5: This test is intended to show the influence of the nature and the level of reinforcing filler in the rubber composition. Table 7 T1 Cl C15 C18 C19 C20 C21 C22 C23 C24 NR (1) 100 - - - - - - - - - EPDM (2) - 100 100 100 100 100 100 100 100 100 Carbon black 1 (3) 47.5 30 47,5 70 - - - - - - Carbon black 2 (4) - - - - 30 47,5 - - - - Carbon black 3 (5) - - - - - - 30 47,5 - - Silica (6) - - - - - - - - 30 47.5 Silane (7) - - - - - - - - 2,4 3,8 Antioxidant (8) 1,5 1,5 1,5 1,5 1 , 1.5 1.5 1.5 1.5 1.5 Stearic acid (9) 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2 , 5 Zinc Oxide (10) 3 3 3 3 3 3 3 3 3 3 Accelerator (11) 0.8 2 2 2 2 2 2 2 0.8 0.8 Sulfur 1.5 0.8 0.8 0, 8 0.8 0.8 0.8 0.8 1.5 1.5 Performance mass loss (%) 100 195 149 112 184 151 182 153 157 126 (1) Natural rubber (2) EPDM "Nordel IP 4570" From the Dow Company (3) Grade N234 Carbon Black to ASTM D-1765 15 (4) Grade N115 Carbon Black to ASTM D-1765 (5) Grade N550 Carbon Black to ASTM D-1765 (6) Silica of grade 160MP (7) Silane liquid "Si69" of the company Dégussa (8) N-1,3-dimethylbutyl-N-phenylparapenylenediamine "Santoflex 6-PPD" from Flexsys (9) Stearin "Pristerene 4931" from Uniqema (10) Industrial grade zinc oxide from Umicore (11) N-cyclohexyl-2-benzothiazyl sulfenamide "Santocure CBS" Flexsys P10-3400 3024155 19 The result of this test shows that the loss of mass performance is always improved compared to the control. It is also observed that carbon black, especially at a level of less than 70 phr, leads to a better result than silica.
    [0031] In summary, the compositions based on at least one terpolymer of ethylene, an α-olefin and a nonconjugated diene, a reinforcing filler and a crosslinking system, which constitute the treads of tires for aircraft give the tires a landing performance greatly improved, especially vis-à-vis the resistance to wear at very high speed.
    [0032] 10 P10-3400
    权利要求:
    Claims (14)
    [0001]
    REVENDICATIONS1. Aircraft tire whose tread comprises a rubber composition based on at least a first diene elastomer, a reinforcing filler and a crosslinking system, which first diene elastomer is a terpolymer of ethylene, an α-olefin and a non-conjugated diene.
    [0002]
    2. The tire of claim 1 wherein the α-olefin is propylene.
    [0003]
    A tire according to any of claims 1 to 2 wherein the non-conjugated diene is 5-ethylidene-2-norbornene or dicyclopentadiene.
    [0004]
    4. A tire according to any one of claims 1 to 3 wherein the first diene elastomer has at least one of the following characteristics, preferably all: the ethylene units represent between 20 and 90%, preferably between 30 and 70% by weight. mass of the first diene elastomer, the α-olefin units represent between 10 and 80%, preferably from 15 to 70% by weight of the first diene elastomer, the non-conjugated diene units represent between 0.5 and 20% by weight of the first diene elastomer.
    [0005]
    A tire according to any one of claims 1 to 4, wherein the rubber composition further comprises a second elastomer, preferably diene.
    [0006]
    The tire of claim 5 wherein the second elastomer is a highly unsaturated diene elastomer selected from the group consisting of polybutadienes, polyisoprenes, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.
    [0007]
    7. A tire according to any one of claims 1 to 6 wherein the level of the first diene elastomer in the rubber composition is more than 50 phr, preferably more than 60 phr.
    [0008]
    8. A tire according to any one of claims 1 to 4, wherein the first diene elastomer is the only elastomer of the rubber composition.
    [0009]
    9. A tire according to any one of claims 1 to 8 wherein the reinforcing filler comprises a carbon black. P10-3400 3024155 21
    [0010]
    10. The tire of claim 9 wherein the reinforcing filler is made of 100% by weight of a carbon black.
    [0011]
    11. A tire according to any one of claims 1 to 9 wherein the reinforcing filler comprises an inorganic filler, preferably a silica.
    [0012]
    12. A tire according to any one of claims 1 to 11 wherein the reinforcing filler content is 20 to 70 phr, preferably 25 to 50 phr.
    [0013]
    A tire according to any one of claims 1 to 12 wherein the rubber composition contains 0 to 20 phr of a liquid plasticizer.
    [0014]
    Tire according to Claim 13, in which the level of liquid plasticizer is equal to 0. P10-3400
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    同族专利:
    公开号 | 公开日
    BR112017000797A2|2019-02-05|
    FR3024155B1|2016-07-22|
    EP3172062A1|2017-05-31|
    EP3172062B1|2018-09-12|
    WO2016012261A1|2016-01-28|
    BR112017000797B1|2021-04-13|
    US20170204260A1|2017-07-20|
    CN106536217A|2017-03-22|
    引用文献:
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    US20040023002A1|2002-07-30|2004-02-05|Edward Wyndham|Ultimate drywall tape|
    WO2011078859A1|2009-12-23|2011-06-30|Michelin Recherche Et Technique S.A.|Rubber composition for aircraft tire treads|
    FR2989633A1|2012-04-24|2013-10-25|Michelin & Cie|CARCASS FRAME FOR AIRCRAFT TIRE|
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    US3093621A|1960-03-29|1963-06-11|Du Pont|Sulfur-curable elastomeric copolymers of ethylene, alpha-olefins, and 5-methylene-2-norbornene|
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    US3331793A|1964-05-25|1967-07-18|Du Pont|Abrasion resistant vulcanizates comprising epd rubber, carbon black, and minor amounts of natural rubber or sbr|
    US4814384A|1986-05-14|1989-03-21|Uniroyal Chemical Company, Inc.|Tire having tread composition comprised of EPDM/unsaturated rubber blend|
    JPH0618950B2|1986-06-17|1994-03-16|株式会社ブリヂストン|Rubber composition|
    AU6302801A|2000-05-09|2001-11-20|Verizon Lab Inc|Stream-cipher method and apparatus|
    FR2999582B1|2012-12-17|2015-02-13|Michelin & Cie|PNEUMATIC COMPRISING A RUBBER COMPOSITION COMPRISING AN EPOXY RESIN AND A POLYACID|FR3044008B1|2015-11-19|2017-12-08|Michelin & Cie|TIRE TREAD FOR TIRE AIRCRAFT|
    FR3044009B1|2015-11-19|2017-12-08|Michelin & Cie|TIRE TREAD FOR TIRE AIRCRAFT|
    FR3044010A1|2015-11-19|2017-05-26|Michelin & Cie|TIRE TREAD FOR TIRE AIRCRAFT|
    FR3044007B1|2015-11-19|2017-12-08|Michelin & Cie|TIRE TREAD FOR TIRE AIRCRAFT|
    法律状态:
    2015-06-26| PLFP| Fee payment|Year of fee payment: 2 |
    2016-01-29| PLSC| Publication of the preliminary search report|Effective date: 20160129 |
    2016-07-21| PLFP| Fee payment|Year of fee payment: 3 |
    2017-07-24| PLFP| Fee payment|Year of fee payment: 4 |
    2018-07-25| PLFP| Fee payment|Year of fee payment: 5 |
    2020-04-10| ST| Notification of lapse|Effective date: 20200306 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1457052A|FR3024155B1|2014-07-22|2014-07-22|PNEUMATIC FOR AIRCRAFT|FR1457052A| FR3024155B1|2014-07-22|2014-07-22|PNEUMATIC FOR AIRCRAFT|
    CN201580039597.3A| CN106536217A|2014-07-22|2015-07-09|Aircraft tyre|
    US15/327,901| US20170204260A1|2014-07-22|2015-07-09|Aircraft tire|
    PCT/EP2015/065760| WO2016012261A1|2014-07-22|2015-07-09|Aircraft tyre|
    EP15738042.9A| EP3172062B1|2014-07-22|2015-07-09|Aircraft tyre|
    BR112017000797-5A| BR112017000797B1|2014-07-22|2015-07-09|AIRPLANE PNEUMATIC|
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