Rubber composition and hose incorporating same

Abstract

The invention relates to a rubber composition which can be used in the crosslinked state to form at least one layer of a hose (10), and to a hose in which at least one layer (11, 13) is made of this composition. The invention is suitable for any hose for conveying fluids under pressure, preferably a multi-layer hose for a motor vehicle. The inventive rubber composition based on at least one elastomer comprises a reinforcing filler comprising at least one shredded or thermally decomposed recycled carbon black from waste rubber-based articles, and functionalized lignin in powder form, and a cross-linking system comprising sulfur and / or peroxides.

Description

TECHNICAL FIELD

[0001] The present invention relates to a rubber composition based on at least one elastomer, which can be used to form at least one layer of a hose in a crosslinked state, and a hose in which at least one layer is made of this composition. The present invention is applicable to single-layer or multi-layer hoses for transporting fluids under pressure, preferably multi-layer hoses for transporting fluids under a pressure equal to or greater than 2×10 5 Pa, and the fluid can be a liquid (such as water or coolant), a supercritical gas or fluid (such as in an air-conditioning circuit), a gas mixture (such as air in an intake circuit), or fuel. The present invention is generally applicable to any hose for transporting fluids used in heat engines, electric motors, or fuel cells (such as hydrogen) for motor vehicles, railways, watercraft, aircraft, or spacecraft, as well as any industrial facility or residence for transporting pressurized fluids. BACKGROUND ART

[0002] It is well known that rubber hoses for motor vehicle cooling circuits generally include an inner layer designed to be in contact with the coolant being transported, at least one reinforcing structure on top of the inner layer (usually a reinforcement formed by knitted, twisted, or woven yarns, such as PET, aromatic polyamide, or rayon), and an outer layer on top of the reinforcement and exposed to the air surrounding the hose. These inner and outer layers are usually made of rubber compositions reinforced with fillers, the fillers containing carbon black of fossil origin and of reinforcing grade (i.e., conventional carbon black usually described as "virgin", usually obtained by thermal decomposition or incomplete combustion of hydrocarbons), which may be coupled with or replaced by mineral reinforcing inorganic fillers such as silica or kaolin.

[0003] In recent years, studies have been conducted on coupling such carbon black with another reinforcing filler that is neither of fossil origin nor of mineral origin (i.e., a filler of biological origin (from biomass), such as lignin), in order to reduce the portion of fossil or mineral components in the composition and, in exchange, increase the portion of components of biological origin. The following patent documents related to rubber compositions for hoses containing partially bio-based reinforcing fillers can be particularly mentioned.

[0004] WO2023 / 025808A1 has, for example, a rubber composition crosslinked by peroxide for a hose, which contains:

[0005] - In its Examples 1-2: 150 parts by mass of EPDM rubber, 70 PCE of "L1" lignin modified by hydrothermal treatment, and 60 PCE of virgin carbon black "N-550", and

[0006] - In its Examples 3-4: 100 parts by mass of EPDM rubber, 50 PCE of "L2" lignin modified by hydrothermal treatment, and 50 PCE of virgin carbon black "N-550".

[0007] EP 4,059,996 A1 has a rubber composition crosslinked by sulfur, for example for a hose, which comprises:

[0008] - In its Example Ab: 100 parts by mass of nitrile rubber (NBR), 40 PCE of "HTC" lignin modified by hydrothermal treatment, and 20 PCE of virgin carbon black "N550",

[0009] - In its Example Bb: 100 parts by mass of polychloroprene rubber (CR), 40 PCE of "HTC" lignin modified by hydrothermal treatment, and 20 PCE of virgin carbon black "N550",

[0010] - In its Example Cb: 100 parts by mass of EPDM rubber, 40 PCE of "HTC" lignin, and 20 PCE of virgin carbon black "N550",

[0011] - In its Example Db: 100 parts by mass of natural rubber (NR), 40 PCE of "HTC" lignin, and 20 PCE of virgin carbon black "N550",

[0012] - In its Example Es: 100 parts by mass of bromobutyl rubber (BIIR), 5 PCE of "HTC" lignin modified by hydrothermal treatment, and 55 PCE of virgin carbon black "N660", and

[0013] - In its Example Eb: 100 parts by mass of bromobutyl rubber (BIIR), 40 PCE of "HTC" lignin modified by hydrothermal treatment, and 20 PCE of virgin carbon black "N660".

[0014] The drawback of the rubber compositions (which use virgin carbon black and modified lignin as reinforcing fillers) tested in these examples from WO2023 / 025808 A1 and EP 4,059,996 A1 is their reduced sustainable mass fraction, which is at most 22% in said examples. Summary of the Invention

[0016] The object of the present invention is to provide a rubber composition which can be used to form at least one layer of a hose in a crosslinked state, wherein said composition in particular remedies the above drawbacks of the prior art, while also being suitable for use in a crosslinkable state and having properties from the crosslinked state which are satisfactory for said layer of the hose.

[0017] The applicant has just found that this object is achieved if a mixed reinforcing filler comprising the following is used in a rubber composition crosslinkable with sulfur or peroxide:

[0018] - Recycled carbon black from the shredding and thermal decomposition of waste rubber-based products; and

[0019] - Functionalized lignin in powder form;

[0020] At least one layer of the hose can then be obtained, which, compared to a "control" rubber composition, differs from the composition according to the invention only in the use of virgin (i.e., non-recycled) carbon black coupled to the same functionalized lignin and which has:

[0021] - In the crosslinkable state: generally maintained, even improved, usability and scorch resistance; and

[0022] - In the crosslinked state: after thermo-oxidative aging, substantially maintained, even improved, physical and mechanical properties and, compared to the "control" composition, generally not more disadvantageous;

[0023] Thereby imparting to the hose at least equivalent service characteristics and operating performance compared to a hose incorporating said "control" composition.

[0024] In other words, a rubber composition according to the invention based on at least one elastomer can be used to form at least one layer of a hose in the crosslinked state and comprises a reinforcing filler and a crosslinking system comprising sulfur and / or peroxide, and thus the reinforcing filler comprises:

[0025] At least one recycled carbon black from the shredding or thermal decomposition of waste rubber-based products; and

[0026] Functionalized lignin in powder form.

[0027] The expression "a rubber composition that can be used to form at least one layer of a hose in the crosslinked state" should be understood as a rubber composition for a hose based on at least one elastomer.

[0028] The expression "based on" in this specification should be understood to mean that the composition or component under consideration mainly comprises the component in question by weight, i.e., a fraction of more than 50%, preferably more than 75% by mass and which can range up to 100%.

[0029] "At least one recycled carbon black from the shredding and pyrolysis of waste rubber-based articles" shall be understood to mean said or each recycled carbon black (i.e., non-prime carbon black, also known as "reclaimed carbon black") obtained substantially by shredding and then by pyrolysis (such as thermal decomposition, (steam) thermocracking or desulfurization) of shredded waste articles made of or mainly made of at least one rubber (such as tires, hoses, joints, belts or any other rubber industrial product). "Shredding" and "shredded" in this specification are generally understood to mean respectively the crushing of waste rubber-based articles, possibly supplemented by shredding, and the product of the continuous operation of crushing and possible shredding of waste articles.

[0030] "Functionalized lignin" in this specification shall be understood to mean carbon lignin modified by hydrothermal hydrolysis or by another method for modification / purification to obtain a purified lignin extract. It is well known that lignin is a major component of lignocellulosic biomass and consists of phenolic polymer-type branched macromolecules particularly containing carbonyl (C=O), aliphatic hydroxyl and phenolic hydroxyl functional groups. The functionalized lignin usable in the present invention may particularly have all or part of these functional groups.

[0031] According to an embodiment of the present invention, the functionalized lignin in powder form comprises:

[0032] - particles without surface CO or COO groups; and / or

[0033] - is kraft lignin, for example from the wood of gymnosperm trees such as conifers.

[0034] Note that the combination of said at least one recycled carbon black and functionalized lignin is used to impart physical properties (such as density, hardness, volume resistivity) and mechanical properties (such as M100 tangent modulus, elongation at break and stress, compression deformation at 100% deformation) to the crosslinked compositions according to the present invention (both with sulfur and with peroxides), which are respectively sufficient for the hoses according to the present invention, for which at least one layer is composed of this composition and has service performance and functional performance (such as pressure resistance, dynamic performance and aging resistance) equivalent to those of the hoses incorporated with the "control" composition (which differs from the composition of the present invention only in that the carbon black coupled to the same functionalized lignin is prime).

[0035] Advantageously, said at least one recycled carbon black may have reinforcing properties similar to those of the reinforcing-grade prime carbon black selected from the ASTM N300, N400, N500, N600 and N700 series, for example similar to those of the carbon black selected from the N500 or N600 series (such as similar to those of N550 or N660 carbon black, non-limiting).

[0036] According to another aspect of the present invention, in addition to the at least one elastomer, the composition comprises a crosslinking system and functionalized lignin in powder form:

[0037] A recycled powder mixture applied to the shredded waste rubber-based articles, the recycled powder mixture comprising the products of a thermal decomposition reaction by thermolysis, pyrolysis or desulfurization;

[0038] The recycled powder mixture comprises the at least one recycled carbon black and is, for example, micronized, especially in the case where the reaction is thermolysis or pyrolysis.

[0039] Advantageously, the recycled powder mixture may comprise the at least one recycled carbon black with a mass fraction of 80% to 99% and inorganic substances with a mass fraction of 1% to 20%, which particularly comprise silica and / or zinc compounds, wherein the micronized recycled powder mixture is from, for example, the pyrolysis of waste tires.

[0040] In the present specification, "reinforcing filler" should be understood to mean a filler comprising a separate reinforcing grade filler for the at least one elastomer uniformly dispersed in the composition, which is provided that the reinforcing filler may further comprise:

[0041] - Reinforcing organic fillers other than the at least one recycled carbon black, such as virgin carbon black of the same or different grade as the recycled carbon black, and / or another carbon filler (such as graphite or carbon nanotubes); and / or

[0042] - Reinforcing inorganic fillers (such as transparent fillers, such as silica), which may be of mineral or biological origin.

[0043] According to a preferred embodiment of the present invention which may comprise any one of the foregoing features, the reinforcing filler may further comprise at least one virgin (i.e., non-recycled) carbon black having, for example, a BET specific surface area measured according to ASTM D6556 standard, which is 10 - 50 m 2 / g, for example 15 - 30 m 2 / g, such as carbon black from the N500 or N600 series (such as N550 or M660, non-limiting).

[0044] According to another general feature of the present invention which may comprise any one of the foregoing features, the composition may comprise 10 - 120 PCE of the at least one recycled carbon black and 2 - 90 PCE of functionalized lignin (PCE: parts by weight relative to 100 parts of elastomer).

[0045] Note that incorporating functionalized lignin into the reinforcing filler is not incompatible with using a large amount of carbon black in the composition, which is used to impart satisfactory mechanical properties.

[0046] According to another general feature of the invention (which may include any of the foregoing features), the at least one elastomer may be selected from ethylene-propylene-diene terpolymers (EPDM), isobutene-isoprene copolymers (IIR), halogenated isobutene-isoprene copolymers (XIIR), silicone rubbers, fluorosilicone rubbers, acrylic rubbers such as polyacrylate (ACM) and ethylene polyacrylate (AEM), and brominated copolymers of isobutene-p-methylstyrene. According to one embodiment, the at least one elastomer may be selected from ethylene-propylene-diene terpolymers (EPDM) and acrylic rubbers such as polyacrylate (ACM) and ethylene polyacrylate (AEM).

[0047] However, it should be noted that other rubbers in addition to the above-mentioned rubbers may be used in the composition according to the invention as a function of the properties sought for the layer or each layer of the hose.

[0048] According to a specific embodiment of the invention:

[0049] - The at least one elastomer is made of at least one EPDM;

[0050] - The crosslinking system comprises a peroxide or sulfur; and

[0051] - The composition comprises 15-100 PCE of the at least one recycled carbon black and 5-80 PCE of the functionalized lignin.

[0052] Preferably, the at least one non-oiled EPDM has:

[0053] - A mass level of units from ethylene of 52-70% and a mass level of units from non-conjugated dienes (such as ethylidene norbornene) of 4-7%, and more preferably

[0054] - A Mooney viscosity ML(1+4) at 125 °C of 70-90.

[0055] For example, a mixture of two non-oiled EPDMs may be used, one of which has a mass level of units from ethylene of 53-57% and a Mooney viscosity ML(1+4) at 125 °C of 75-85, and the other of which has a mass level of units from ethylene of 66-70% and a Mooney viscosity ML(1+4) at 125 °C of 80-90.

[0056] According to another general aspect of the present invention which may relate to any of the foregoing features, a composition according to the present invention based on at least one EPDM comprises:

[0057] - 10 - 80 PCE of said at least one virgin carbon black, which has a BET specific surface area measured, for example, according to the ASTM D6556 standard, which is 10 - 50 m 2 / g;

[0058] - 10 - 80 PCE, preferably 15 - 80 PCE of said at least one recycled carbon black; and

[0059] - 15 - 80 PCE of said functionalized lignin;

[0060] wherein the sum of the amounts of said at least one virgin carbon black and said at least one recycled carbon black in the composition is 60 - 110 PCE.

[0061] Even more preferably, according to another general aspect of the present invention which may relate to any of the foregoing features, the sum of the amounts of said at least one virgin carbon black and said at least one recycled carbon black in a composition according to the present invention based on at least one EPDM is 70 - 100 PCE, and

[0062] the sum of the amounts of said at least one virgin carbon black, recycled carbon black and functionalized lignin in the composition is 100 - 130 PCE.

[0063] Also preferably, the reinforcing filler comprises:

[0064] - Functionalized lignin according to 15 - 30% by mass fraction; and

[0065] - Said at least one virgin carbon black and said at least one recycled carbon black according to 70 - 85% of the total mass fraction of carbon black.

[0066] According to another general aspect of the present invention which may relate to any of the foregoing features, a composition according to the present invention based on at least one EPDM or at least acrylic rubber such as (ACM) or (AEM) in the crosslinked state can advantageously have a volume resistivity per unit measured according to the IEC 626313 standard of more than 10 6 Ohm.cm, preferably more than 10 8 Ohm.cm and even more preferably more than 10 12 Ohm.cm.

[0067] Note that, thanks to the functionalized lignin, the compositions according to the invention, for example based on at least one EPDM or at least an acrylic rubber such as (ACM) or (AEM), therefore have a high resistivity, despite the use of large amounts of carbon black known to impair this resistivity (by increasing the conductivity). In particular, when the fluid is a cooling fluid (for example of the glycolic acid-water type), this high resistivity is especially useful to minimize the electrochemical breakdown of the inner layer of the hose in contact with the fluid transported by the hose, without impairing the resistance of the hose to its external environment.

[0068] Note that better resistivity can be obtained using recycled carbon black compared to compositions containing virgin carbon black.

[0069] Furthermore, it is noted that the above-mentioned amounts for the at least one recycled carbon black, the functionalized lignin and optionally the at least one virgin carbon black, combined with the use of a suitable plasticizer system, serve to limit the Mooney ML (1+4) viscosity at 100° C. of the crosslinkable composition (regardless of the elastomeric matrix used), while resisting its premature crosslinking (scorch), thus making the composition from the present invention suitable for use by compounding followed by extrusion.

[0070] As plasticizer system for the composition according to the invention, at least one plasticizer oil and / or at least one plasticizer resin can be used, wherein it is provided that the plasticizer system according to the invention preferably comprises at least one oil selected from mineral oils, oils from biomass (including modified or unmodified vegetable oils) and mixtures thereof.

[0071] Still more preferably, as plasticizer system, at least one oil is used which is chosen from paraffinic, naphthenic and aromatic mineral oils, for example at least partly naphthenic mineral oils (which contain paraffinic, naphthenic and aromatic functional groups).

[0072] As regards the crosslinking system, it is used to chemically crosslink the rubber composition by subsequently vulcanizing the hose comprising the layer or each layer made of the composition at a temperature of, for example, 160-200° C. If a peroxide is used, the crosslinking system may comprise an organic peroxide and a crosslinking auxiliary, for example selected from triallyl cyanurate (TAC) and triallyl isocyanurate (TAIC).

[0073] According to another general aspect of the invention which may relate to any of the aforementioned features, the composition may have a mass fraction of sustainable components (i.e. bio-derived and recycled) of more than 10%, preferably more than 20 or 25%, more preferably more than 30%, for example equal to or greater than 40%, wherein the sustainable components include the at least one recycled carbon black and the functionalized lignin.

[0074] Note that according to the sustainable components present in the composition being greater than 25%, 30% or even 40%, the at least one recycled carbon black and the functionalized lignin may consist of the sustainable components, or as a variant, further include one or more sustainable components.

[0075] According to another general aspect of the present invention, the crosslinkable rubber composition from the present invention is prepared by using a method substantially comprising the following consecutive steps:

[0076] a) Adding the components of the composition except for the crosslinking system to an internal mixer;

[0077] b) Performing a thermomechanical operation in the internal mixer in the step until the maximum "drop" temperature is reached, such as 120 - 130 °C;

[0078] c) Recycling and then cooling the resulting mixture; and

[0079] d) Adding the crosslinking system having sulfur or peroxide to an external mixer (such as a cylinder) at a temperature of 95 - 105 °C, and mechanically operating the resulting crosslinkable composition in the external mixer.

[0080] As a variant, the crosslinking system may be added during step b) of the thermomechanical operation, such as controlling the maximum temperature at 120 °C, or added during a second introduction into the internal mixer after the precursor mixture produced by the first step is cooled.

[0081] As demonstrated by the results shown in the following examples, the physical properties (such as density, hardness, volume resistivity) and mechanical properties (such as M100 at 100% deformation, elongation at break and stress, compression set) of the crosslinked composition according to the present invention are generally sufficient such that the hoses incorporating them can convey fluids with good dynamic strength at a pressure of at least 2×10 5 Pa, even after thermal oxidative aging at 150 °C for 168 hours.

[0082] A hose for conveying liquids, gases or supercritical fluids according to an embodiment of the present invention is suitable for conveying fluids at a pressure equal to or greater than 2×10 5 Pa, the hose being for a heat engine or an electric motor, or for a fuel cell of an automotive, railway, waterborne, aviation or aerospace vehicle, the hose comprising a radially inner rubber tube, at least one reinforcing layer, and a rubber covering layer.

[0083] The hose according to this embodiment of the present invention is such that at least one of the inner tube and the covering layer is made of the rubber composition in the crosslinked state as defined above.

[0084] Note that the hose according to this embodiment may also include a barrier layer of plastic based on at least one thermoplastic polymer. The barrier layer may form the innermost radially layer of the hose, or form an "insulating layer" between the inner tube and the reinforcing layer or between the inner tube and the rubber intermediate layer.

[0085] According to another general aspect of the invention which may involve any one of the foregoing features, a rubber composition for a hose based on at least one elastomer comprises a reinforcing filler and a crosslinking system comprising sulfur and / or peroxide, wherein the reinforcing filler comprises:

[0086] (i) A recycled powdered mixture applied to shredded waste rubber-based articles, which contains the products of a thermal decomposition reaction by pyrolysis, thermolysis or desulfurization,

[0087] The recycled powdered mixture comprises:

[0088] At least one recycled carbon black with a mass fraction of 80% to 99%, and

[0089] An inorganic substance with a mass fraction of 1% to 20%, particularly containing silica and / or zinc compounds;

[0090] (ii) Functionalized lignin in powder form, and

[0091] (iii) Optionally, at least one virgin carbon black having a BET specific surface area measured, for example, according to the ASTM D 6556 standard, which is 10 - 50 m 2 / g.

[0092] According to another general aspect of the invention which may involve any one of the foregoing features, the recycled powdered mixture applied to shredded waste rubber-based articles is micronized and contains the products of a thermal decomposition reaction by pyrolysis or thermolysis.

[0093] According to another general aspect of the invention which may involve any one of the foregoing features, the recycled powdered mixture is from the pyrolysis of waste tires. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] Other features, advantages and details of the present invention will become apparent upon reading the description of several embodiments of the implementation of the present invention given below in conjunction with the accompanying drawings, in which:

[0095] Figure 1

[0096] Figure 1 is a partially labeled lateral and perspective schematic view of a multi-layer hose according to an embodiment of the present invention.

[0097] Figure 2

[0098] Figure 2 Partial side and perspective views of a multi-layer hose according to another embodiment of the present invention, with parts labeled.

[0099] Figure 3

[0100] Figure 3 Partial side and perspective views of a multi-layer hose according to another embodiment of the present invention, with parts labeled.

[0101] Figure 4

[0102] Figure 4 Partial side and perspective views of a multi-layer hose according to another embodiment of the present invention, with parts labeled. DETAILED DESCRIPTION OF THE INVENTION

[0104] from Figure 1 The multi-layer hose 10 can convey any fluid, such as those already mentioned, under a pressure preferably equal to or greater than 2×10 5 Pa, and it includes a radially inner tube 11, a reinforcing layer 12, and a radially outer covering layer 13, where it is stipulated that at least one of the tube 11 and the covering layer 13 is made of a rubber composition according to the present invention as defined above, for example based on at least one of the following:

[0105] - EPDM, especially in the case of hoses for conveying water or coolant in the heat engines, electric motors, or fuel cells of motor vehicles; or

[0106] - ACM or AEM (e.g. type), especially in the case of hoses for conveying air (e.g. for the air intake of motor vehicles).

[0107] As described above, as a variant, the tube 11 and the covering layer 13 can each be based on at least one IIR or XIIR (halobutyl rubber, such as chlorinated or brominated), at least one silicone rubber optionally having fluorine (e.g. MQ, PMQ, PVMQ, VMQ or FMQ, FVMQ), or at least one brominated copolymer of isobutene - p-methylstyrene (e.g. trade name).

[0108] The reinforcing layer 12 can include, but is not limited to, a knitted, twisted, or woven fabric based on multifilament yarns made of one or more textile materials (e.g. polyamide (e.g. aramid), polyester (e.g. PET), or rayon), where the term "yarn" generally refers to a thread based on a large number of elementary small-diameter filaments twisted together and a ply yarn obtained by twisting several threads.

[0109] from Figure 2 The multi-layer hose 20 from Figure 1The multi-layer hose is different in that the inner tube 21 is covered by the intermediate layer 22, the intermediate layer 22 itself is covered by the reinforcing layer 23, and the reinforcing layer 23 is covered by the covering layer 24, wherein at least one of the tube 21 and the covering layer 24 is made of the composition according to the present invention.

[0110] from Figure 3 The multi-layer hose 30 from Figure 2 is different from the multi-layer hose from

[0111] in that the inner tube 31 is covered by the internal reinforcing layer 32, the internal reinforcing layer 32 itself is covered by the intermediate layer 33, the intermediate layer 33 is covered by the external reinforcing layer 34, and then covered by the covering layer 35, wherein at least one of the tube 31, the intermediate layer 33 and the covering layer 35 is made of the composition according to the present invention.

[0111] from Figure 4 The multi-layer hose 40 from Figure 2 is different from the multi-layer hose from

[0112] in that the inner tube 41 is covered by the plastic barrier layer 42 formed into a ply, and then covered by the intermediate layer 43, the intermediate layer 43 is covered by the reinforcing layer 44, and the reinforcing layer 44 itself is covered by the covering layer 45, wherein at least one of the tube 41, the intermediate layer 43 and the covering layer 45 is made of the composition according to the present invention.

[0112] Note that the multi-layer hose according to the present invention may include an arrangement of layers that are different from those shown in Figures 1 - 4 in terms of their number of layers and their respective functions.

[0113] Prepare the control rubber composition C1, the rubber compositions C2 - C6 not in accordance with the present invention, and the rubber compositions I1 - I8 according to the present invention:

[0114] The control rubber composition C1, the rubber compositions C2 - C6 not in accordance with the present invention, and the rubber compositions I1 - I8 according to the present invention are prepared substantially by the following method.

[0115] Add the components of each composition except the crosslinking system to a type internal mixer. Then, perform a thermomechanical operation (mixing length: 30 seconds to 2 minutes) in one step until a maximum "drop" temperature of about 125 °C is reached.

[0116] Recover and cool the resulting mixture, and then add the crosslinking system to an external mixer with a cylinder at 100 °C while mixing all substances for about 2 minutes in a mechanical operation step.

[0117] Then, the obtained crosslinkable rubber compositions C1-C6 and I1-I8 are formed into cylindrical test pieces for measuring the properties (Mooney viscosity and scorch time) in the non-crosslinked state, and into dumbbell-shaped test pieces for measuring the mechanical properties (hardness, M100 tangent modulus at 100% deformation, and fracture properties) in the crosslinked state after vulcanizing the test pieces at 180 °C.

[0118] For each cylindrical crosslinkable test piece, the Mooney ML(1+4) viscosity is measured at 100 °C according to the ISO 289-1 standard, and the scorch time t5 without premature crosslinking is measured at 135 °C according to the ISO 289-2 standard.

[0119] Furthermore, for each dumbbell-shaped crosslinked test piece, the following are measured:

[0120] a) The density according to the ISO 2781 standard;

[0121] b) The Shore A hardness after 3 s according to the ISO48-4 standard;

[0122] c) The M100 tangent modulus in uniaxial traction according to the ISO37:2017 standard;

[0123] d) The fracture stress and fracture elongation in uniaxial traction according to the ISO37:2017 standard;

[0124] e) Compression set:

[0125] After 30 minutes at 25%: 72 h / 130 °C, according to the ISO815-1 standard (Method B); and

[0126] After 25%: 72 h / 140 °C (“FCA” specification: Fiat Chrysler Automobiles) according to the ISO 1817 standard; and

[0127] f) The volume resistivity measured at 1000 V.

[0128] Each test piece made from the rubber compositions C1-C6 and I1-I8 is thermally oxidized and aged in hot air at 150 °C for 168 h, and then the hardness, fracture stress, and elongation are measured again as specified in b) and d) above.

[0129] Table 1 below gives the formulations of the compositions C1-C3 and I1-I5 prepared as described above.

[0130] [Table 1]

[0131] C1 C2 C3 I1 I2 I3 I4 I5 EPDM 1* 60 60 60 60 60 60 60 60 EPDM 2* 40 40 40 40 40 40 40 40 Original carbon black* 57.5 115 38.3 19.2 76.6 19.2 Lignin* 57.5 115 38.3 76.6 57.5 19.2 19.2 Recycled carbon black* 38.3 19.2 57.5 19.2 76.6 Plasticizer* 40 40 40 40 40 40 40 40 MgO 5.7 5.7 5.7 5.7 5.7 5.7 5.7 5.7 PEG 4000 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 Reagents used* 3 3 3 3 3 3 3 3 Quinoline antioxidant 1 1 1 1 1 1 1 1 Imidazole antioxidant 1 1 1 1 1 1 1 1 TAC promoter 1 1 1 1 1 1 1 1 Organic diperoxide 10.5 10.5 10.5 10.5 10.5 10.5 10.5 10.5 Total 279.1 279.1 279.1 279.0 279.1 279.1 279.1 279.1 Mass fraction of sustainable components 20％ 0％ 41％ 27％ 34％ 41％ 14％ 34％

[0132] Table 2 below gives the formulations of the compositions C4 - C6 and I6 - I8 prepared as above.

[0133] [Table 2]

[0134]

[0135]

[0136] The components used for these compositions, identified by the * symbol in Tables 1 and 2, have the following characteristics:

[0137] - EPDM 1: Mass concentration of units from ethylene: 55%; mass concentration of units from norbornene ethylidene: 5.5%; and Mooney ML(1 + 4) viscosity at 125 °C: 80.

[0138] - EPDM 2: Mass concentration of units from ethylene: 68%; mass concentration of units from norbornene ethylidene: 4.9%; and Mooney ML(1 + 4) viscosity at 125 °C: 85.

[0139] - AEM 1: A terpolymer consisting of ethylene units, methyl acrylate units, and crosslinking sites, and having a Mooney ML(1 + 4) viscosity of 16.5 at 100 °C.

[0140] - AEM 2: A terpolymer consisting of ethylene units, methyl acrylate units, and crosslinking sites, and having a Mooney ML(1 + 4) viscosity of 18.5 at 100 °C.

[0141] - Virgin carbon black (Table 1, EPDM matrix): Grade 6, BET specific surface area according to ASTM D 6556 of 20 m 2 / g, and iodine absorption index according to ASTM D 1510 of 20 mg / g.

[0142] - Virgin carbon black (Table 2, AEM matrix): Grade 5, BET specific surface area according to ASTM D 6556 of 40 m 2 / g, and iodine absorption index according to ASTM D 1510 of 43 mg / g.

[0143] - Lignin: Kraft lignin from the wood of gymnosperm trees (such as conifers), sold by UPM under product number TSD020 - 1000.

[0144] - Recycled carbon black from waste tire pyrolysis, sold by Contact under the name Sold.

[0145] - Plasticizer: Paraffin mineral oil.

[0146] - Reagents used: a mixture of fatty acid derivatives.

[0147] Table 3 below shows the basic rheological properties of the resulting compositions C1 - C3 and I1 - I5, including each of them:

[0148] - Mooney ML(1 + 4) viscosity measured at 100 °C according to ISO 289 - 1 standard;

[0149] - Initial coking time t5 without premature crosslinking at 135 °C according to ISO 289 - 2 standard; and

[0150] - Rheological properties: time ts1 and t10, t50, t70, t90 (from the start to the end of crosslinking) measured by an oscillatory matrix rheometer (at 180 °C for 20 minutes) according to ISO 6502 standard.

[0151] [Table 3]

[0152]

[0153] Table 4 below shows the physical and mechanical properties of the resulting crosslinked compositions C1 - C3 and I1 - I5 measured on dumbbell - shaped test pieces as described above.

[0154] [Table 4]

[0155]

[0156]

[0157] Compared with control composition C1 (a mixture containing 50% of the same original carbon black and 50% of the same lignin as reinforcing filler) Compared with , A set of properties obtained for the compositions I1 - I5 according to the present invention in Tables 3 - 4 shows that:

[0158] - In the non - crosslinked state, for the overall retained applicability of the compositions I1 - I5, and even improvement for I1, I2, I4, and I5 (especially see the reduction of their viscosity ML(1 + 4) compared to the viscosity of composition C1); and

[0159] - In the crosslinked state: for the overall retained mechanical properties of the compositions I1, I4, and I5 (even after thermal - oxidative aging), and even partial improvement for composition I4 (especially see the breaking stress and M100 modulus of composition I4 before aging, which increase compared to those of composition C1, and also see the compression deformation of composition I4, which is of the same order of magnitude as those of composition C1); and

[0160] For the overall retained resistivity of the compositions I1 - I5, and even improvement for composition I1.

[0161] Compared with composition C2 not in accordance with the present invention (containing 100% of the same virgin carbon black as reinforcing filler) Compared with , the resulting properties of the compositions I1 - I5 according to the invention show that:

[0162] - In the non - crosslinked state, for the overall retention applicability of the compositions I1 - I5, and even an improvement for I1 (especially see its reduced viscosity ML(1 + 4) compared to composition C2); and

[0163] - In the crosslinked state:

[0164] The mechanical properties of compositions I1, I4 and I5 are not overly impaired at all (even after thermo - oxidative aging), and even a partial improvement for composition I4 (especially see the M100 modulus of composition I4, which is increased compared to the M100 modulus of composition C2, and also see the compression set of compositions I4 and I5, which is of the same order of magnitude as that of composition C2, and even the reduction of composition I4 at 72 h / 140 °C); and

[0165] The resistivity of the compositions I1 - I5 is very significantly improved.

[0166] Compared with composition C3 not in accordance with the present invention (containing 100% of the same lignin as reinforcing filler) Compared with , the resulting characteristics of the compositions I1 - I5 according to the invention show that:

[0167] - In the non - crosslinked state, the applicability of the compositions I1 - I5 is very significantly improved (especially see its ML(1 + 4) viscosity, which is much reduced compared to the ML(1 + 4) viscosity of composition C3, and its coking time t5 is generally longer than those of composition C3); and

[0168] - In the crosslinked state:

[0169] For the compositions I1 - I5, even after thermo - oxidative aging, generally improved mechanical characteristics (especially see the breaking stress and elongation at break, and compression set of compositions I4 and I5, which are of the same order of magnitude as those of composition C3); and

[0170] The improved resistivity of compositions I1, I2, I3 and I5.

[0171] Table 5 below shows the basic rheological properties of the resulting compositions C4 - C6 and I6 - I8, including each of them:

[0172] - Mooney ML(1 + 4) viscosity measured at 100 °C according to ISO 289 - 1 standard;

[0173] - The initial coking time t5 without premature crosslinking at 135 °C according to ISO 289-2 standard; and

[0174] - Rheological properties: The times ts1 and t1, t50, t70, t90 (from the start to the end of crosslinking) measured by an oscillating matrix rheometer (for 20 minutes at 180 °C) according to ISO 6502 standard.

[0175] [Table 5]

[0176]

[0177] The following Table 6 shows the physical and mechanical properties of the resulting crosslinked compositions C4 - C6 and I6 - I8 measured on dumbbell-shaped test specimens as shown above.

[0178] [Table 6]

[0179]

[0180]

[0181] Compared with the compositions C4 - C6 that do not conform to the present invention, the properties obtained for the compositions I6 - I8 of the present invention show that:

[0182] - In the non-crosslinked state, the overall retained applicability for the compositions I6 - I8; and

[0183] - In the crosslinked state:

[0184] The mechanical properties for the compositions I6 - I8 are not overly impaired at all (even after thermal oxidative aging) (in particular, see that the breaking stress is greater than 7 MPa and the elongation at break exceeds 100% after thermal oxidative aging at 150 °C for 168 hours); and

[0185] Compared with the composition C5 containing only virgin carbon black, the resistivity of the compositions I6 - I8 is very significantly improved. In summary, these examples show that:

[0186] - The compositions I1 - I8 according to the present invention, particularly characterized by the coupling of recycled carbon black and lignin, generally show performance of the same order of magnitude as the compositions C1 - C3 in both the non-crosslinked state and the crosslinked state, and in particular,

[0187] - The compositions I1, I2, I4, I5, I6, I7 and I8 are further characterized by the addition of virgin carbon black to the recycled carbon black and lignin, which further improves some of these properties compared to those of the compositions C1 - C6, and even more particularly

[0188] - Compositions I4 and I5, particularly characterized in that the mass fraction of lignin in the reinforcing filler is about 17%, allows for a further improvement of some of these properties compared to compositions C1 - C3 (compared to compositions I1 and I2, whose reinforcing fillers contain about 33% and 67% of lignin, respectively).

[0189] These examples also show that compositions I1, I2, I3, I5, I6, I7, and I8 according to the invention advantageously have a mass fraction of sustainable components (i.e., of biological origin and recycled) of more than 10% (composition I7), more than 20% (composition I6), more than 25% (composition I8), even more than 30% (compositions I2, I3, and I5), and even more than 40% (composition I3).

[0190] These examples also show that replacing at least a part of the virgin carbon black with recycled carbon black can increase the resistivity of the composition.

Claims

1. A rubber composition based on at least one elastomer, wherein the composition can be used to form at least one layer of a hose in the crosslinked state and comprises a reinforcing filler and a crosslinking system comprising sulphur and / or peroxide, The reinforcing filler comprises: At least one recycled carbon black derived from shredded or thermally decomposed waste rubber-based products; and Functionalized lignin in powder form.

2. The rubber composition according to claim 1, wherein the at least one recycled carbon black has reinforcing properties similar to those of a composition of reinforcing carbon blacks selected from the ASTM N300, N400, N500, N600 and N700 series, such as those of carbon blacks selected from the N500 or N600 series.

3. The rubber composition according to claim 1 or 2, wherein in addition to the at least one elastomer, the composition comprises a crosslinking system and a functionalized lignin: a recycled powdery mixture applied to the shredded waste rubber-based article, the recycled powdery mixture comprising products of a thermal decomposition reaction by thermal cracking, pyrolysis or devulcanization; The recycled powdery mixture comprises the at least one recycled carbon black and is, for example, micronized, in particular in the case where the reaction is thermal cracking or pyrolysis.

4. The rubber composition according to claim 1 or 2, wherein the recycled powdery mixture comprises 80 to 99% by mass of the at least one recycled carbon black and 1 to 20% by mass of an inorganic substance, the inorganic substance particularly comprising silicon dioxide and / or a zinc compound, wherein the recycled powdery mixture in micronized form comes, for example, from the pyrolysis of waste tires.

5. The rubber composition according to claim 1 or 2, wherein the functionalized lignin in powder form: - comprising particles without surface CO or COO groups; and / or - is kraft lignin, for example from the wood of gymnosperm trees such as conifers.

6. The rubber composition according to claim 1, wherein the reinforcing filler further comprises at least one virgin carbon black having a BET specific surface area, for example, measured according to ASTM D 6556 standard, of 10-50 m 2 / g.

7. The rubber composition according to claim 1, wherein the composition comprises 10-120 PCE of the at least one recycled carbon black and 2-90 PCE of the functionalized lignin (PCE: parts by weight relative to 100 parts of elastomer).

8. The rubber composition according to claim 1, wherein the at least one elastomer is selected from ethylene-propylene-diene terpolymers (EPDM), isobutylene-isoprene copolymers (IIR), halogenated isobutylene-isoprene copolymers (XIIR), silicone rubbers, fluorosilicone rubbers, acrylic rubbers such as polyacrylates (ACM) and ethylene polyacrylates (AEM), and brominated copolymers of isobutylene-p-methylstyrene.

9. The rubber composition according to claim 7 or 8, wherein: - said at least one elastomer is made of at least one EPDM; - the crosslinking system comprises peroxide or sulfur; and - said composition comprises 15-100 PCE of said at least one recycled carbon black and 5-80 PCE of said functionalized lignin.

10. The rubber composition according to claim 6, wherein the composition comprises: - 10-80 PCE of at least one raw carbon black having a BET specific surface area, for example, measured according to ASTM D6556 standard, of 10-50 m 2 / g; - 15-80 PCE of said at least one recycled carbon black; and -15-80 PCE of the functionalized lignin; wherein the sum of the amounts of the at least one virgin carbon black and the at least one recycled carbon black in the composition is 60-110 PCE.

11. The rubber composition according to claim 10, wherein the sum of the amounts of the at least one virgin carbon black and the at least one recycled carbon black in the composition is 70-100 PCE, and wherein the sum of the amounts of the at least one virgin carbon black, the at least one recycled carbon black and the functionalized lignin in the composition is 100-130 PCE.

12. The rubber composition according to claim 10 or 11, wherein the reinforcing filler comprises: - 15-30% by weight of functionalized lignin; and - said at least one virgin carbon black and said at least one recycled carbon black in a total mass fraction of carbon black of 70-85%.

13. The rubber composition according to claim 9, wherein the composition has a crosslinked state measured according to the IEC626313 standard of more than 10 6 Ohm·cm, preferably more than 10 8 Volume resistivity in Ohm·cm.

14. The rubber composition according to any one of the preceding claims, wherein the composition has a mass fraction of sustainable ingredients exceeding 25%, preferably exceeding 30%, for example equal to or greater than 40%, wherein the sustainable ingredients include the at least one recycled carbon black and the functionalized lignin.

15. A hose for conveying liquids, gases or supercritical fluids, the hose being used in heat engines or electric motors, or in fuel cells for automotive, railroad, water, aviation or aerospace vehicles, the hose comprising a radial inner tube, at least one reinforcing layer and a covering layer, wherein the hose is suitable for conveying liquids, gases or supercritical fluids at a speed of 2×10 or more. 5 The invention relates to a method for conveying a fluid under a pressure of Pa, wherein at least one of the inner tube and the cover layer is made of the rubber composition in a cross-linked state according to any one of claims 1 to 14.

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