Process for preparing a rubbery mixture in liquid phase

Abstract

The invention relates to a method for continuously obtaining a coagulum based on at least one elastomer and a reinforcing filler, said method comprising the following steps: continuously supplying a first stream of a fluid consisting of an elastomer latex, continuously supplying a second stream of a fluid consisting of an aqueous dispersion of a reinforcing filler comprising at least one pyrolysis carbon black, bringing said first stream into contact with said second stream in a mixing zone of a coagulation reactor, the continuous contact inducing the formation of a coagulum of the elastomer latex with the aqueous dispersion of the reinforcing filler, continuously recovering said coagulum obtained in the previous step.

Description

Title of the invention: Process for preparing a rubbery mixture in liquid phase. FIELD OF THE INVENTION

[0001] The present invention relates to the field of masterbatches and their method of obtaining them in the liquid phase. Masterbatches are used in particular for the manufacture of elastomeric compositions, especially those intended for the manufacture of rubber articles such as pneumatic and non-pneumatic tires. STATE OF THE ART

[0002] In recent years, limiting the environmental impact of the manufacture of rubber articles, in particular pneumatic or non-pneumatic tires, and their use has become a major issue for manufacturers in the sector.

[0003] Research and development initiatives to produce rubber articles such as pneumatic or non-pneumatic tires comprising elastomeric compositions based on recycled or bio-based materials have increased. For example, it has been proposed to use pyrolysis carbon blacks as a total or partial substitute for conventional carbon blacks (also called virgin carbon black) used as a reinforcing filler in the elastomeric compositions constituting pneumatic or non-pneumatic tires; conventional carbon blacks being obtained from non-renewable raw materials of petroleum or fossil origin such as tars, oils and / or gases.

[0004] However, this partial or total substitution of these conventional carbon blacks by pyrolysis carbon blacks is accompanied by a number of disadvantages, including in particular that of its poor dispersion in the elastomeric matrix.

[0005] However, it is known that poor dispersion of a reinforcing filler in the elastomeric matrix of a composition results in inferior mechanical properties of that composition. This decrease in mechanical properties is unacceptable for a manufacturer of rubber articles, particularly for a manufacturer of pneumatic or non-pneumatic tires.

[0006] Thus, there is still a need for elastomeric compositions, particularly for the manufacture of rubber articles, especially for pneumatic or non-pneumatic tires, making it possible to limit the environmental impact of the manufacture and use of these elastomeric compositions while reconciling both good dispersion of the reinforcing charge and maintenance of mechanical properties.

[0007] The present invention makes it possible to meet this need. Surprisingly, the applicant has discovered that it is possible to obtain elastomeric compositions comprising a reinforcing filler from a recycling process, in particular a pyrolysis carbon black, exhibiting good dispersion in the elastomeric matrix while maintaining the fatigue resistance properties of the elastomeric composition containing it.

[0008] Thus, an object of the present invention relates to a method for continuously obtaining a coagulum based on at least one elastomer and a reinforcing filler, said method comprising the following steps: a. to continuously supply a first flow of a fluid consisting of an elastomeric latex, b. continuously supply a second flow of a fluid consisting of an aqueous dispersion of a reinforcing filler comprising at least one pyrolysis carbon black, c. bringing said first stream into contact with said second stream in a mixing zone of a coagulation reactor, the continuous contact inducing the formation of a coagulum of the elastomer latex with the aqueous dispersion of the reinforcing filler, d. continuously recover the coagulum obtained in the previous step. DETAILED DESCRIPTION OF THE INVENTION

[0009] As explained previously, an object of the present invention relates to a method for continuously obtaining a coagulum based on at least one elastomer and a reinforcing filler, said method comprising the following steps: a. to continuously supply a first flow of a fluid consisting of an elastomeric latex, b. continuously supply a second flow of a fluid consisting of an aqueous dispersion of a reinforcing filler comprising at least one pyrolysis carbon black, c. bringing said first stream into contact with said second stream in a mixing zone of a coagulation reactor, the continuous contact inducing the formation of a coagulum of the elastomer latex with the aqueous dispersion of the reinforcing filler, d. continuously recover the coagulum obtained in the previous step.

[0010] The term "coagulum" means the product of the coagulation of one or more elastomers in the form of latex and one or more reinforcing fillers in the form of particulate matter in a liquid, preferably an aqueous liquid, the elastomer(s) and the reinforcing filler(s) coming together to form a single mass.

[0011] The process for obtaining the coagulum according to the invention is a continuous process. A "continuous process" is defined as a process in which the feeding of raw materials, their transformation, and the production of the final product (in this case, the coagulum) occur without interruption between the different stages. A continuous process differs from a discontinuous process (or batch process) in which the feeding of raw materials occurs at a specific time and for a defined period, then the feeding stops, and the transformation stage begins and is stopped once the raw materials have reached the desired stage of transformation. The product is then extracted, and a new cycle (new batch) starts in the same equipment.

[0012] The expression "composition based on" means a composition comprising the mixture and / or the in situ reaction product of the different constituents used, some of these constituents being able to react and / or being intended to react with each other, at least partially, during the different phases of manufacturing the composition; the composition can thus be in a totally or partially crosslinked state or in a non-crosslinked state.

[0013] By the expression "part by weight per hundred parts by weight of elastomer" (or pce), it is necessary to understand the part, by mass per hundred parts by mass of elastomer or rubber, the two terms being synonymous.

[0014] In this document, unless expressly stated otherwise, all percentages (%) indicated are percentages (%) by mass.

[0015] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than a to less than b (that is to say, bounds a and b excluded) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from a to b (that is to say, including the strict bounds a and b).

[0016] The compounds mentioned in the description may be of fossil origin, derived from biomass. Obviously, the compounds mentioned may also come from the recycling of materials already used; that is to say, they may be, partially or totally, derived from a recycling process, or even obtained from raw materials themselves derived from a recycling process. This includes, in particular, polymers, plasticizers, etc.

[0017] By "elastomeric matrix" or "elastomeric matrix", we mean the entire set of elastomer(s) present in the elastomeric composition.

[0018] For the purposes of this invention, "majority" or "majority" means that the compound is the majority compound among compounds of the same type in The composition is defined as the major component, meaning the one that represents the largest quantity by mass among the compounds of the same type. In other words, the mass of this compound represents more than 50% of the total mass of the compounds of the same type in the composition, for example, at least 51%. For example, in a system comprising a single elastomer, this elastomer is the major component within the meaning of the present invention; and in a system comprising two elastomers, the major elastomer represents more than half of the total mass of the elastomers, meaning the mass of this elastomer represents more than 50%, for example, at least 51%, of the total mass of the elastomers. Similarly, a major component is the one representing the largest mass among the components in the composition. In other words, the mass of this component represents more than 50%, for example, at least 51%, of the total mass of the components in the composition.

[0019] All glass transition temperature values ​​“Tg” are measured in a known manner by Differential Scanning Calorimetry (DSC) according to ASTM D3418 (2008).

[0020] The expression "consists essentially of" followed by one or more characteristics means that components or steps which do not significantly modify the properties and characteristics of the invention may be included in the process or material of the invention, in addition to the components or steps explicitly listed.

[0021] By "dry" is meant a product whose moisture content does not exceed 1% by weight of the total weight of the product. The moisture content is measured by any technique known to a person skilled in the art.

[0022] By "dry coagulum" is meant a coagulum whose moisture content does not exceed 1% by weight of the total weight of the coagulum. The moisture content is measured by any technique known to a person skilled in the art.

[0023] By "masterbatch" is meant an elastomer-based composite into which a filler, in particular a reinforcing filler, has been introduced. In other words, a masterbatch is a premix of a filler, in particular a reinforcing filler, and at least one elastomer.

[0024] Elastomer

[0025] The elastomer(s) usable within the framework of the process of the invention may preferably be one or more diene elastomers.

[0026] In the usual way, the terms "elastomer" and "rubber" are used interchangeably in the text.

[0027] By "diene" elastomer (or indistinctly rubber), whether natural or synthetic, is to be understood in a known manner as an elastomer consisting at least in part (i.e., a homopolymer or a copolymer) of diene monomer units (monomers bearing two carbon-carbon double bonds, conjugated or not). In this application, diene elastomers are by definition non-thermoplastic.

[0028] These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". Generally, "essentially unsaturated" means a diene elastomer derived at least in part from conjugated diene monomers, having a proportion of diene motifs or units (conjugated dienes) greater than 15% (mole percent); thus, diene elastomers such as butyl rubbers or EPDM-type diene and alpha-olefin copolymers do not fall under the preceding definition and can be described in particular as "essentially saturated" diene elastomers (low or very low proportion of diene motifs, always less than 15%).

[0029] The term diene elastomer, which can be used in compositions according to the invention, is particularly understood to mean: • any homopolymer of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms; • any copolymer of a diene, conjugated or not, having from 4 to 18 carbon atoms and at least one other monomer.

[0030] The other monomer may be ethylene, an olefin or a diene, conjugated or not.

[0031] Suitable conjugated dienes are those having from 4 to 12 atoms of carbon, in particular 1,3-dienes, such as 1,3-butadiene and isoprene.

[0032] Suitable as unconjugated dienes are unconjugated dienes having 6 to 12 carbon atoms, such as 1,4-hexadiene, ethylidene norbornene, dicyclopentadiene.

[0033] Suitable olefins are vinylaromatic compounds having 8 to 20 carbon atoms and aliphatic α-monoolefins having 3 to 12 carbon atoms.

[0034] Suitable examples of vinylaromatic compounds include styrene, ortho-, meta-, para-methylstyrene, the commercial mixture "vinyl-toluene", para-tert-butylstyrene.

[0035] As aliphatic α-monoolefins, acyclic aliphatic α-monoolefins having from 3 to 18 carbon atoms are particularly suitable.

[0036] More specifically, the diene elastomer can be: • any homopolymer of a conjugated diene monomer, in particular any homopolymer obtained by polymerization of a conjugated diene monomer having 4 to 12 carbon atoms; • any copolymer obtained by copolymerization of one or more dienes conjugated together or with one or more vinylaromatic compounds having 8 to 20 carbon atoms; • any copolymer obtained by copolymerization of one or more dienes, conjugated or not, with ethylene, an α-monoolefin or a mixture thereof, such as elastomers obtained from ethylene or propylene.

[0037] In summary, the diene elastomer(s) usable within the scope of the present invention may preferably be chosen from the group of diene elastomers consisting of natural rubber, polybutadienes (abbreviated as "BR"), synthetic polyisoprenes ("IR"), butadiene copolymers, isoprene copolymers and mixtures of these elastomers. Such copolymers are most preferentially chosen from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR) and isoprene-butadiene-styrene copolymers (SBIR).Preferably, the diene elastomer(s) usable within the framework of the present invention may be natural rubber.

[0038] For the production of a coagulum according to the invention, an elastomeric latex can be used, the elastomeric latex being a particular form of elastomer which is in the form of elastomeric particles dispersed in water. The invention preferably relates to diene elastomeric latexes, diene elastomers being those defined above, including preferred modes; in particular, a natural rubber latex may preferably be used.

[0039] More particularly, for natural rubber (NR) which can compose all or part of the elastomer according to the invention, this natural rubber exists in different forms as detailed in chapter 3 “Latex concentrates: properties and composition”, by KF Gaseley, ADT Gordon and TD Pendle in “Natural Rubber Science and Technology”, AD Roberts, Oxford University Press - 1988.

[0040] In particular, several forms of natural rubber latex are marketed: field latex, concentrated natural rubber latex, epoxy latex, deproteinized latex, or pre-laccanized latex.

[0041] Field natural rubber latex is a latex to which ammonia has been added to prevent early coagulation and concentrated natural rubber latex corresponds to a field latex which has undergone a treatment corresponding to a washing followed by a new concentration.

[0042] The different categories of concentrated natural rubber latex are listed in particular according to ASTM D 1076-06. Among the rubber latexes Natural rubber latex concentrates are distinguished, in particular, by their so-called "HA" ("high ammonia") and "LA" ("low ammonia") quality; for the purposes of this invention, HA quality concentrated natural rubber latex will be advantageously used. Natural rubber latex may be pre-modified physically or chemically (centrifugation, enzymatic treatment, chemical modification, etc.). The latex may be used directly or pre-diluted in water to facilitate its application. Preferably, elastomeric latex, particularly diene elastomeric latex, and especially natural rubber latex, may contain one or more antioxidants as described below.

[0043] It should be noted that it is possible to consider using one or more natural rubber latexes in a cutting process, or a cutting process of one or more natural rubber latexes with one or more synthetic rubber latexes.

[0044] As a synthetic elastomer latex, the latex may in particular consist of a synthetic diene elastomer already available in emulsion form (for example a butadiene and styrene copolymer, SBR, prepared in emulsion), or of a synthetic diene elastomer initially in solution (for example an SBR prepared in solution) which is emulsified in a mixture of organic solvent and water, generally by means of a surfactant.

[0045] A SBR latex, particularly an emulsion-prepared SBR (“ESBR”) or a solution-prepared SBR (“SSBR”), and more particularly an emulsion-prepared SBR, is particularly suitable for the invention. There are two main types of emulsion copolymerization processes for styrene and butadiene: one, the hot process (carried out at a temperature close to 50°C), is suitable for preparing highly branched SBRs, while the other, the cold process (carried out at a temperature ranging from 15°C to 40°C), produces more linear SBRs. For a detailed description of the effectiveness of several emulsifiers usable in the said hot process (depending on the rates of said emulsifiers), one may, for example, refer to the two articles by CW Carr, M. Kolthoff, EJ Meehan, University of Minnesota, Minneapolis, Minnesota, which appeared in the Journal of Polymer Science of 1950, Vol. V, No. 2, pp. 201-206, and of 1951, Vol. VI, No. 1, pp.73-81. Regarding comparative examples of implementation of said cold process, one may refer for example to article V2 Industrial and Engineering Chemistry, 1948, Vol. 5 40, No. 5, pp. 932-937, EJ Vandenberg, GE Hulse, Hercules Powder Company, Wilmington, Delaware + and to article V2 Industrial and Engineering Chemistry, 1954, Vol. 46, No. 5, pp. 1065-1073, JR Miller, HE Diem, BF Goodrich Chemical Co., Akron, Ohio. .

[0046] In the case of an SBR elastomer (ESBR or SSBR), an SBR with an average styrene content, for example between 20% and 35%, is used. weight relative to the total weight of the copolymer, or a high styrene content, for example 35 to 45% by weight relative to the total weight of the copolymer, a molar content of vinyl bonds in the butadiene portion between 15% and 70%, a content (molar %) of trans-1,4 bonds between 15% and 75% and a Tg between -10°C and -55°C; such an SBR can be advantageously used in blending with a BR preferably having more than 90% (molar %) of cis-1,4 bonds.

[0047] According to a preferred embodiment of the invention, a natural rubber latex, in particular a concentrated natural rubber latex, specifically a concentrated natural rubber latex of so-called "HA" quality and / or "LA" quality, will be used. More particularly, the concentrated natural rubber latex of so-called "HA" quality.

[0048] According to another preferred embodiment of the invention, a natural rubber latex from the field will be used.

[0049] Reinforcing charge

[0050] The reinforcing filler used in the context of the present invention comprises at least one pyrolysis carbon black.

[0051] The term “reinforcing filler” refers to any type of filler known for its ability to reinforce an elastomeric composition usable in particular for the manufacture of tires, such as virgin carbon blacks, pyrolysis carbon blacks, carbon nanotubes, siliceous or aluminous mineral fillers, etc.

[0052] Pyrolysis carbon black

[0053] For the purposes of this invention, "pyrolysis carbon black" means carbon black obtained by pyrolyzing a material comprising at least one carbon polymer and carbon black, hereinafter referred to as the material to be pyrolyzed, for example, in the context of recycling such a material. The physical state of the material to be pyrolyzed is irrelevant, whether it is in the form of a dry powder, granules, strip, or any other form, in a cross-linked or non-cross-linked state.

[0054] Preferably, the material to be pyrolyzed can be recovered from manufactured articles or products generated during their manufacture / production (such as by-products or scrap); these manufactured articles can be selected from the group consisting of pneumatic tires, non-pneumatic tires, industrial conveyor belts, transmission belts, rubber seals, rubber hoses, shoe soles, and windshield wipers. More preferably still, the pyrolysis carbon black usable within the scope of the present invention is a carbon black obtained from a process of pyrolysis where the material to be pyrolyzed comes from manufactured articles selected from the group consisting of pneumatic and non-pneumatic bandages.

[0055] Pyrolysis in the context of the present invention means any type of thermal decomposition in the absence of oxygen, the raw material of which is the material to be pyrolyzed as defined above. Pyrolysis carbon blacks are therefore distinguished from so-called industrial and / or ASTM grade virgin carbon blacks in that the carbonaceous raw material used for pyrolysis is a material comprising at least one carbon polymer and a carbon black, and not materials derived from petroleum fractions or coal, or from oils of natural origin or oils from recycling processes (such as pyrolysis oil).

[0056] The pyrolysis carbon blacks usable within the framework of the present invention are distinguished from known carbon blacks such as industrial carbon blacks, in particular so-called "fumace" carbon blacks, notably by a higher ash content.

[0057] Preferably, the pyrolysis carbon black usable within the framework of the present invention has an ash content in the range of 5% to 30% by weight, more preferably from 8% to 25% by weight, more preferably from 10% to 22% by weight, relative to the total weight of the pyrolysis carbon black.

[0058] Preferably, the pyrolysis carbon black usable within the framework of the present invention has a sulfur content greater than 2% by weight, preferably in the range of 2.5% to 5% by weight, relative to the total weight of the pyrolysis carbon black.

[0059] Preferably, the pyrolysis carbon black usable within the framework of the present invention has a zinc content greater than or equal to 2% by weight, preferably in a range of 2.5% to 8% by weight, relative to the total weight of the pyrolysis carbon black.

[0060] Preferably, the pyrolysis carbon black usable within the framework of the present invention has a specific surface area STSA measured according to ASTM D 6556-2021 in the range of 20 to 200 m2 / g, more preferably in the range of 30 to 90 m2 / g.

[0061] Preferably, the pyrolysis carbon black usable within the framework of the present invention has a void volume measured according to ASTM D7854-21 and at a pressure of 50 MPa within a range of 30 to 60 ml / 100g, more preferably within a range of 35 to 55 ml / 100g.

[0062] The ash content is determined by calcination in platinum capsules in a muffle furnace at 825°C according to the following protocol. One capsule is previously The capsule is identified before each series of measurements and is tared to the nearest 0.1 mg; the mass is noted as PO. Five grams of pyrolysis carbon black sample are introduced into the capsule and weighed precisely to the nearest 0.1 mg; this mass is noted as PI. The capsule and its contents are pre-calcined using a Bunsen burner until fumes appear and the product ignites. Once the product has completely burned, the capsule and its contents are placed in a muffle furnace heated to 825°C for 1 hour. After 1 hour, the capsule is removed from the furnace and immediately placed in a desiccator at room temperature. When the capsule and ash have returned to room temperature, the capsule is weighed again to obtain mass P2. Finally, the ash content (% ash) can be obtained using the formula below:

[0063] [Math.l] P2 - PO % ashes ~ ——— x 100 PI - PO

[0064] The zinc content in pyrolysis carbon black is determined after calcination of the sample, followed by resuspension of the ash in an acidic medium and quantification by ICP-AES (inductively coupled plasma atomic emission spectroscopy). The ash is obtained by following the above protocol. Approximately 100 mg of ash (test sample) is taken and placed in a PFA (perfluoroalkoxy) tube for use with a HotBlock hot plate. Then, 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, and 0.5 mL of 40% hydrofluoric acid are added. The tube is then sealed and heated at 130°C for 2 hours. After cooling, the contents are then transferred using ultrapure water into a 100 mL PTFE (polytetrafluoroethylene) volumetric flask already containing 2 g of boric acid (to neutralize the hydrofluoric acid). Ultrapure water is then added to the calibration mark.The resulting solution is diluted 100-fold by taking 1 mL from a 100 mL PTFE flask previously containing 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, 0.5 mL of 40% hydrofluoric acid, and 2 g of boric acid. This diluted solution is then filtered through a 0.45 µm GHP syringe filter before being analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Prior to the analysis of the diluted solution, at least five standards are analyzed by ICP-AES at zinc concentrations of 0, 0.5, 1, 2, and 5 mg / L. These standards were prepared in 100 mL volumetric flasks by diluting a commercially available solution certified to a zinc concentration of 1 g / L.

[0065] These volumetric flasks previously contain 8 mL of 37% concentrated hydrochloric acid, 3 mL of 65% concentrated nitric acid, 0.5 mL of 40% hydrofluoric acid, and 2 g of boric acid. The standard solutions are analyzed by ICP-AES at a wavelength of XZn = 202.613 nm. For each standard concentration (c), the intensity of the The zinc signal IZn is plotted on a graph IZn = f(c), which corresponds to the calibration curve (of the type y = ax + b). The sample solution (diluted solution) of unknown concentration is then measured under the same conditions as the standards. The measured intensity is related to the concentration using the calibration curve obtained previously. The ash concentration [c] in mass % is thus obtained directly from the software, since the sample size and volume were previously recorded. The zinc concentration in pyrolysis black [c] in mass % is obtained using the following equation:

[0066] [Math.2] klxM “ [cJcb^s » 100 « % cendres

[0067] The determination of the sulfur content in pyrolysis carbon black is carried out using a LECO furnace. LECO sulfur analyzers are designed to measure, in particular, the sulfur content in organic and / or inorganic materials by combustion and non-dispersive infrared detection. Before measuring the sulfur content of the sample, the pods are cleaned and the furnace is calibrated. The LECO furnace pods are cleaned beforehand: the empty pod is analyzed under the same conditions as the samples. The calibration curve is prepared using a commercial standard called "BBOT" with a purity greater than 99.99% and a guaranteed carbon (C), hydrogen (H), nitrogen (N), oxygen (O), and sulfur (S) content. This content is as follows: C%: 72.52; H%: 6.09; N%: 6.51; 0% 7.43 and S% 7.44. We weigh approximately exactly 10 ± 3, 20 ± 3 and 40 ± 3 mg of BBOT in a capsule.The standard / pod assembly is introduced into the combustion furnace, regulated at 1350 °C under pure oxygen. The combination of the furnace temperature and the analysis flow rate causes the sample to combust and release sulfur and / or carbon as SO2(g). After 20 seconds, oxygen begins to flow through the lance to accelerate the combustion of materials that are difficult to burn. The sulfur and / or carbon, as SO2(g), are carried by an oxygen flow through the infrared detection cells. The instrument software plots a line connecting the introduced standard mass and the observed response (area) on the detector. This yields a calibration curve. After thoroughly cleaning the sampling equipment, approximately 80 ± 5 mg of pyrolysis carbon black is weighed and introduced into a LECO furnace pod.The area of ​​the observed SO2 peak is related to the concentration using the calibration curve. The instrument's software then calculates the mass percentage of sulfur in the sample based on the mass of sample introduced into the capsule.

[0068] Pyrolysis carbon blacks are marketed for example by the company Scandinavian Enviro Systems under the reference "P550 HD" or by the company Bolder Industries under the reference BolderBlack.

[0069] Virgin carbon black

[0070] The reinforcing charge usable within the scope of the present invention may further comprise at least one carbon black other than pyrolysis carbon black, this carbon black being called "virgin carbon black" because it is not produced from materials already containing carbon black. Virgin carbon black is produced from materials derived from petroleum fractions or coal, or from oils of natural origin or oils obtained from recycling processes (such as pyrolysis oil).

[0071] As virgin carbon blacks, all carbon blacks are suitable, in particular carbon blacks conventionally used in tires or their treads, especially industrial carbon blacks, more specifically so-called “furnace” carbon blacks.

[0072] Among virgin carbon blacks, special mention will be made of reinforcing virgin carbon blacks of the 100, 200, 300 series, or blacks of the 500, 600 or 700 series (ASTM grades D-1765-23b published on December 15, 2023), such as for example NI 15, N134, N234, N326, N330, N339, N347, N375, N550, N683, N772 blacks.

[0073] Virgin carbon blacks can be used in their isolated state, as commercially available, or in any other form, for example as a carrier for certain rubberizing additives used. Virgin carbon blacks could, for example, already be incorporated into the diene elastomer, particularly isoprene, in the form of a masterbatch (see, for example, applications WO97 / 36724-A2 or WO99 / 16600-A1).

[0074] Siliceous or aluminous mineral fillers

[0075] The reinforcing filler usable within the framework of the present invention may also include at least one inorganic reinforcing filler. Suitable inorganic reinforcing fillers include mineral fillers of the siliceous type, preferably silica (SiO2), or of the aluminous type, in particular alumina (Al2O3).The silica used can be any reinforcing silica known to those skilled in the art, including any precipitated or fumed silica. Precipitated silica can be produced from non-renewable raw materials, including those derived from inorganic sand (silicon dioxide from inorganic sand), recycled materials such as foundry sands, end-of-life tires and in particular the treads of end-of-life tires consisting mainly of silica as a reinforcing filler, or from bio-based raw materials such as organic waste from plants, preferably inedible organic waste from plants.

[0076] By non-renewable raw material, we mean a raw material that does not regenerate on a human timescale. These are therefore exhaustible resources. Examples include minerals such as stones or sand, metals, gas, and oil.

[0077] Among the plants having silicon dioxide in their tissues, we can mention mustard, grasses, maize, sugar cane bagasse, rice, wheat and in particular mustard husks, bamboo leaves, ears of maize, rice husks, wheat husks.

[0078] Silica derived from non-renewable raw materials such as natural inorganic sand is usually obtained by heating sand in a glass furnace in the presence of sodium carbonate. The resulting sodium silicate is then dissolved in water, possibly in the presence of a base such as sodium hydroxide. Precipitated synthetic silica is formed from this aqueous solution by controlled treatment of the silicate with an acid (e.g., a mineral acid and / or an acidifying gas such as carbon dioxide). Sometimes, an electrolyte (e.g., sodium sulfate) may be present to promote the formation of precipitated silica particles. The recovered precipitated silica is amorphous precipitated silica.

[0079] Silica derived from bio-based raw materials such as those mentioned above can, for example, be obtained by burning the bio-based raw material in order to recover the ash of this bio-based material which contains mainly silicon dioxide.For example, in the case of rice husks, and in a process equivalent to that described above for silicas based on non-renewable or recycled mineral raw materials, rice husk ash is generally treated with a strong base such as sodium hydroxide to form an aqueous silicate solution (e.g., sodium silicate). Following this, precipitated synthetic silica is formed by the controlled addition of an acid (e.g., a mineral acid and / or an acidifying gas such as carbon dioxide) in which an electrolyte (e.g., sodium sulfate) may be present to promote the formation of precipitated silica particles derived from rice husks. The recovered precipitated silica is amorphous precipitated silica. Silica derived from rice husk ash is commonly referred to as RHA silica (Rice Husk Ash Silica).Bio-based silicas are available, for example, from suppliers such as Solvay, Evonik, Quechen, Wilmar International, Wuxi... .

[0080] In summary, the synthesis of a precipitated silica usable within the scope of the invention can be carried out from a sodium silicate entirely obtained from bio-based, recycled or non-renewable raw materials, but also from a mixture of bio-based and / or recycled and / or non-renewable raw materials.

[0081] Preferably, the precipitated silica, whether obtained from mineral, non-renewable, recycled or bio-based raw materials, has a specific surface area and a specific surface area CT AB both less than 450 m2 / g, preferably within a range of 30 to 400 m2 / g, in particular 60 to 300 m2 / g.

[0082] Any type of precipitated silica can be used, in particular highly dispersible precipitated silicas (known as "HDS" for "highly dispersible" or "highly dispersible silica"). These precipitated silicas, whether highly dispersible or not, are well known to those skilled in the art.

[0083] Examples include the silicas described in applications WO03 / 016215-A1 and WO03 / 016387-A1. Among the commercial HDS silicas, the following can be used in particular: “Ultrasil ® 5000GR”, “Ultrasil ® 7000GR” from Evonik, “Zeosil ® 1085GR”, “Zeosil® 1115 MP”, “Zeosil® 1165MP”, “Zeosil® Premium 200MP”, “Zeosil® HRS 1200 MP” from Solvay. As non-HDS silica, the following commercial silicas may be used: “Ultrasil® VN2GR”, “Ultrasil® VN3GR” silicas from Evonik, “Zeosil® 175GR” silica from Solvay, “Hi-Sil EZ120G(-D)”, “Hi-Sil EZ160G(-D)”, “Hi-Sil EZ200G(-D)”, “Hi-Sil 243LD”, “Hi-Sil 210”, “Hi-Sil HDP 320G” silicas from PPG, “K160”, “K185”, “K195” silicas from Wilmar International.

[0084] Other examples of inorganic fillers that may be used in compositions may also be cited mineral fillers of the aluminous type, in particular alumina (Al2O3), aluminum oxides, aluminum hydroxides, aluminosilicates, titanium oxides, silicon carbides or nitrides, all of the reinforcing type as described for example in applications WO 99 / 28376-A2, WO 00 / 73372-Al, WO 02 / 053634-A1, WO 2004 / 003067-A1, WO 2004 / 056915-A2, US 6 610 261-B1 and US 6 747 087-B2. Examples include the aluminas “Baikalox A125” or “CR125” (Baïkowski company), “APA-100RDX” (Condéa), “Aluminoxid C” (Evonik) or “AKP-G015” (Sumitomo Chemicals).

[0085] The physical state of the reinforcing inorganic filler is irrelevant, whether it is in the form of dry powder, microbeads, granules, or spheres, or any other suitable densified form. Of course, the term "reinforcing inorganic filler" also includes mixtures of different reinforcing inorganic fillers, in particular silicas as described above.

[0086] Those skilled in the art will understand that, in place of the reinforcing inorganic filler described above, a reinforcing filler of another nature, since this reinforcing charge of another nature would be covered with an inorganic layer such as silica, or would have functional sites on its surface, in particular hydroxyl sites, requiring the use of a coupling agent to establish the bond between this reinforcing charge and the diene elastomer.

[0087] Preferably, pyrolysis carbon black represents more than 50% by weight, more preferably more than 70% by weight, more preferably still more than 90% by weight of the total weight of the reinforcing charge.

[0088] According to one embodiment of the invention, the reinforcing filler consists essentially of pyrolysis carbon black. In this embodiment, pyrolysis carbon black or a mixture of pyrolysis carbon black constitutes the sole reinforcing filler; another reinforcing filler, different from pyrolysis carbon black, may optionally be present but with trace impurities.

[0089] In another embodiment of the invention, the reinforcing filler comprises at least one pyrolysis carbon black and at least one second reinforcing filler other than pyrolysis carbon black. This second reinforcing filler may be selected from the group consisting of virgin carbon blacks, silicas, in particular precipitated silicas, and mixtures of these reinforcing fillers. The virgin carbon blacks and silicas usable in this embodiment of the invention are those described above.Thus, according to one embodiment of the invention, the reinforcing filler may comprise a mixture of at least one pyrolysis carbon black and at least one virgin carbon black, or a mixture of at least one pyrolysis carbon black and at least one silica, in particular at least one precipitated silica, or even a mixture of at least one pyrolysis carbon black, at least one virgin carbon black, and at least one silica, in particular at least one precipitated silica. Preferably, in these embodiments of the invention, pyrolysis carbon black constitutes the major component of this type of mixture. Preferably, in this embodiment, pyrolysis carbon black represents more than 50% by weight, more preferably more than 70% by weight, and more preferably more than 90% by weight of the total weight of the reinforcing filler.

[0090] The total content of the reinforcing filler in the coagulum typically varies from 30 to 90 parts per annum, more preferably from 40 to 80 parts per annum, and even more preferably from 45 to 70 parts per annum. This content is measured by any technique known to those skilled in the art, such as thermogravimetric analysis (TGA).

[0091] Method

[0092] The process for continuously obtaining a coagulum based on at least one elastomer and a reinforcing filler comprising at least one pyrolysis carbon black, includes at least one step a) which is the continuous supply of a first flux of a fluid consisting of an elastomeric latex, in particular a diene elastomeric latex, and more specifically a natural rubber latex. This continuous supply of the first fluid can be achieved using one or more peristaltic pumps from a reservoir containing the elastomeric latex(s). This type of device is described in particular in US patent 6048923, column 10, lines 50 to column 11, line 14.

[0093] The reinforcing filler(s) comprising at least one pyrolysis carbon black are used in step b) of the process of the present invention in the form of a fluid consisting of an aqueous dispersion of said filler (also called "slurry" in English).

[0094] Pyrolysis carbon black and other reinforcing fillers, when present, usable within the scope of the invention are commercially generally in dry form, i.e. in the form of dry powder, microbeads, granules, pellets, beads or any other suitable densified form.

[0095] Pyrolysis carbon black in dry form is contacted with water, the mixture passing, for example, through a colloidal mill to form an aqueous dispersion of reinforcing filler. This aqueous dispersion of pyrolysis carbon black can then pass through a homogenizer which further disperses the pyrolysis carbon black in water to form the second fluid ("slurry") used in the context of the present invention. Devices for obtaining and continuously supplying the second stream of step b) of the process for continuously obtaining a coagulum according to the invention are described in particular in US 6048923, columns 14, lines 35 to 15, lines 40, and in WO2019 / 129999A1, paragraphs

[0013] to

[0019] .

[0096] In step c) of the process, the first stream is brought into contact with the second stream in a mixing zone of a coagulation reactor, the continuous contact of said streams inducing the formation of a coagulum of the elastomer latex with the aqueous dispersion of the reinforcing filler. Preferably, the contact in step c) can be carried out with the following steps: i. to supply the continuous flow of the first elastomeric latex fluid to a mixing zone of a coagulation reactor, defining an elongated coagulation zone extending between the mixing zone and an outlet, ii. to supply the continuous flow of the second fluid from the pressurized aqueous dispersion into the mixing zone of a coagulation reactor to form the coagulum.

[0097] More preferably, the continuous flow of the second fluid is supplied at a higher speed than the continuous flow of the first fluid. This speed differential can, in particular, allow for rapid coagulation. in particular without coagulation agent, elastomer latex with aqueous dispersion of reinforcing filler comprising at least one pyrolysis carbon black.

[0098] The coagulation reactor comprises an inlet for the various streams, a mixing zone, and an outlet. The coagulation zone in the coagulation reactor extends from the mixing zone, preferably increasing gradually in cross-section in the downstream direction from an inlet end to an outlet end. Examples of coagulation reactors and their operating conditions are described in US 6048923, US 6929783, and US 9156955, particularly US 6048923, columns 14 to 20. They may be used for implementing the present invention.The aqueous dispersion of the reinforcing filler, comprising at least one pyrolysis carbon black ("pyrolysis carbon black slurry"), is introduced into the mixing zone preferably as a continuous, high-velocity injected stream, while the elastomeric latex fluid stream, particularly diene elastomer, especially natural rubber latex, is introduced at a relatively low velocity. The high velocity, flow rate, and particle concentration of the fluid consisting of an aqueous dispersion of reinforcing filler comprising pyrolysis carbon black are sufficient to induce high mixing and shear of the latex fluid, flow turbulence of the mixture in at least a portion upstream of the coagulation zone, and substantially complete coagulation with said latex before the outlet end of the coagulation reactor.A substantially complete coagulation can thus be obtained, according to preferred embodiments, without the need to use an acidic or saline coagulation agent. The continuous and simultaneous feeding of the latex fluid stream and the reinforcing filler suspension fluid stream, comprising at least one pyrolysis carbon black, into the mixing zone of the coagulum reactor establishes a continuous flow of coagulum (in the form of a coil or "worm") of said latex and of said filler suspension into the coagulum zone.

[0099] The coagulum is continuously discharged from the outlet of the coagulation reactor in the form of a worm. This discharge is a substantially constant and continuous flow and occurs simultaneously with the continuous feeding of the latex fluid and the aqueous dispersion fluid, comprising at least one pyrolysis carbon black, into the mixing zone of the coagulum reactor. In particular, the worm-like flow and the atmospheric or near-atmospheric pressure conditions at the outlet of the coagulation reactor are highly advantageous for facilitating the control and collection of the coagulum, for example, for subsequent processing, use, and / or drying steps. The feed rates of the elastomeric latex fluid, in particular diene elastomeric latex, preferably natural rubber latex, and the aqueous dispersion of the filler Reinforcing energies, including at least one pyrolysis carbon black, towards the mixing zone of the coagulum reactor can be precisely measured to achieve high yields, with little free latex and little undispersed pyrolysis carbon black in the coagulum exiting the coagulation reactor. The velocity differential between the first and second fluids is important to obtain sufficient turbulence, i.e., sufficiently energetic shear of the elastomeric latex, preferably diene elastomeric latex, and more preferably natural rubber latex, thus promoting complete dispersion of the pyrolysis carbon black particles in the latex fluid and their coagulation. High mixing energies produce a new product (coagulum, in the form of a coil or "worm") with excellent dispersion of the pyrolysis carbon black particles.

[0100] The coagulum in the form of a sausage exiting from the outlet of the mixing zone of the coagulation reactor can be used as such for the manufacture of elastomeric compositions.

[0101] According to a preferred embodiment of the invention, the process further comprises at least one continuous drying step to obtain a dry coagulum, also called a masterbatch. In this step, the coagulum exiting the mixing zone of the coagulation reactor is continuously sent to one or more drying means such as a centrifuge, a drying extruder, an oven, a dryer, a roller tool, etc., and a combination thereof. After the drying step(s), the dry coagulum or masterbatch has a moisture content of 1% or less by weight relative to the total weight of the coagulum, preferably in the range of 0% to 1% by weight relative to the total weight of the coagulum.

[0102] Examples of implementation of one or more drying steps are shown in documents US6048923 column 16 and US6929783, in particular columns 16 to 20 of this document.

[0103] Another object of the present invention is a coagulum obtained by the process of the invention, preferably a coagulum obtained by the process of the invention which includes at least one drying step.

[0104] Preferably, the dry coagulum is used for the manufacture of elastomeric compositions in particular intended to produce a rubber article, preferably semi-finished products for pneumatic or non-pneumatic bandages and / or for producing pneumatic or non-pneumatic bandages.

[0105] Variant with antioxidant

[0106] The coagulum according to the invention may include at least one antioxidant, which may be any antioxidant known to those skilled in the art to prevent or limit the aging of the coagulum attributable to the action of oxygen.

[0107] The antioxidant is preferably chosen from the group consisting of substituted p-phenylenediamines, substituted diphenylamines, substituted triphenylamines, quinoline derivatives, antioxidant phenolic compounds and mixtures thereof. The antioxidant is even more preferably chosen from the group consisting of substituted p-phenylenediamines and mixtures thereof.

[0108] When the antioxidant is a substituted p-phenylenediamine (abbreviated "PPD" or "PPDA"), it is preferably chosen from the group consisting of N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine (better known by the abbreviation "6-PPD"), N-isopropyl-N'-phenyl-p-phenylenediamine (abbreviated "LPPD"), phenyl-cyclohexyl-p-phenylenediamine, N,N'-di(1,4-dimethylpentyl)-p-phenylenediamine, N,N'-diaryl-p-phenylenediamine ("DTPD"), diaryl-p-phenylenediamine ("DAPD"), 2,4,6-tris-(Nl,4-dimethylpentyl-p-phenylenediamino)-l,3,5-triazine ("TAPDT") and their mixtures.

[0109] When the antioxidant is a quinoline derivative (“TMQ”), it is preferably chosen from the group consisting of l,2-dihydro-2,2,4-trimethylquinoline, 6-ethoxy-l,2-dihydro-2,2,4-trimethylquinoline and mixtures thereof.

[0110] By way of example of substituted diphenylamines or triphenylamines, one may cite those described for example in applications WO 2007 / 121936, WO 2008 / 055683 and WO 2009 / 138460. In particular where the antioxidant is a substituted diphenylamine or triphenylamine, it is preferably chosen from the group consisting of 4,4'-bis(isopropylamino)-triphenylamine, 4,4'-bis(l,3-dimethylbutylamino)-triphenylamine, 4,4'-bis(l,4-dimethylpentylamino)-triphenylamine, 4,4',4"-tris(l,3-dimethylbutylamino)-triphenylamine, 4,4',4"-tris(l,4-dimethylpentylamino)-triphenylamine and mixtures thereof.

[0111] When the antioxidant is an antioxidant phenolic compound, it is preferably chosen from the group consisting of 2,2'-methylene bis-4-methyl-6-tert-butylphenol ("BPH"), butyl-hydroxy-toluene ("BHT") and mixtures thereof.

[0112] Of course, in the present description, the term antioxidant can refer to either a single antioxidant compound or a mixture of several antioxidant compounds.

[0113] The antioxidant can be added to the reservoir containing the latex, or to the reservoir containing the reinforcing filler, or injected as a third continuous flow into the mixing zone of the coagulation reactor, or can be added upstream of the centrifuge, or upstream of the drying means, or as described in documents WO2017103518A1 and WO2017103519A1.

[0114] Variant adding second charge

[0115] In one embodiment of the process, the aqueous dispersion of the reinforcing filler may comprise at least one second reinforcing filler other than pyrolysis carbon black; the second reinforcing filler being selected from the group consisting of virgin carbon black, silicas, and mixtures of these reinforcing fillers. When the second filler is virgin carbon black, this virgin carbon black may be brought into contact with water at the same time as the pyrolysis carbon black is brought into contact with water. In other words, the pyrolysis carbon black and the virgin carbon black may be brought into contact with water in a single reservoir, the whole then passing through the colloidal mill to form an aqueous dispersion of reinforcing filler, then to the homogenizer, and then to the coagulation reactor as described above.In another embodiment of the invention, virgin carbon black can be brought into contact with water in a separate tank from the one containing pyrolysis carbon black and water. In this embodiment, two separate streams can be sent to a single colloidal mill to form the aqueous dispersion of reinforcing filler, or each separate stream is sent continuously to a separate colloidal mill and a separate homogenizer, and then each stream feeds into the coagulation reactor as described above; that is, the two streams of aqueous dispersion of fillers are sent under pressure continuously into the mixing zone of the coagulation reactor at a significantly higher velocity (at least 10 times higher) than the velocity of the elastomeric latex fluid flow, in particular diene elastomeric latex, preferably natural rubber latex.

[0116] In the embodiment where the second filler can be a reinforcing inorganic filler, for example silica, particularly precipitated silica, a coupling agent for the silica to the diene elastomer can also be used. These coupling agents (or bonding agents) are well known and are at least bifunctional compounds designed to ensure sufficient chemical and / or physical connection between the reinforcing inorganic filler and the diene elastomer. In particular, at least bifunctional organosilanes or polyorganosiloxanes are used. By "bifunctional," we mean a compound having a first functional group capable of interacting with the reinforcing inorganic filler and a second functional group capable of interacting with the elastomer, particularly the diene.For example, such a bifunctional compound may comprise a first functional group including a silicon atom, said first functional group being capable of interacting with the hydroxyl groups of a reinforcing inorganic charge, and a second functional group including a sulfur atom, said second functional group being capable of interacting with the elastomer, in particular a diene elastomer.

[0117] Preferably, the organosilanes are chosen from the group consisting of polysulfide organosilanes (symmetric or asymmetric) such as bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT and marketed under the name "Si69" by Evonik, or bis-(3-triethoxysilylpropyl) disulfide, abbreviated TESPD and marketed under the name "Si75" by Evonik, polyorganosiloxanes, mercaptosilanes, blocked mercaptosilanes, such as octanethioate of S-(3-(triethoxysilyl)propyl) is marketed by Momentive under the name "NXT Silane." More preferably, the organosilane is a polysulfide organosilane. In this embodiment of the invention, the reinforcing inorganic filler is contacted with water in a stirred tank. According to a preferred embodiment of this variant, the coupling agent of the reinforcing inorganic filler and the reinforcing inorganic filler are added simultaneously to the water, and the mixture is continuously passed through a colloid mill and then a homogenizer. In another embodiment of this variant, the coupling agent is contacted with the aqueous dispersion of the reinforcing inorganic filler upstream of the colloid mill and upstream of the homogenizer.In another embodiment, the coupling agent is brought into contact with the reinforcing inorganic filler downstream of the homogenizer and upstream of the mixing zone of the coagulation reactor. Thus, the coupling agent reacts with the reinforcing inorganic filler before the coagulation phase, and the reinforcing inorganic filler can be described as pre-grafted or hydrophobicated by the coupling agent. In yet another variant, a commercially available hydrophobic reinforcing inorganic filler, such as Agilon silica, can be used.In these different embodiments, the hydrophobic inorganic reinforcing charge flow is sent under pressure and at high speed to the mixing zone of the coagulation reactor, either at the same time as the continuous pressurized flow of the reinforcing charge including pyrolysis black, or with a delay of a few seconds (2 to 10 seconds) relative to the flow of the reinforcing charge fluid including pyrolysis carbon black.

[0118] Variant adding a second elastomer

[0119] In a variant of the process of the invention, which can be combined with the various embodiments mentioned above, a second elastomer latex different from the first latex, in particular a second diene elastomer latex, or more preferably a synthetic elastomer latex. As previously indicated, the second latex can be mixed with the first latex in the same reservoir, and this mixture supplies the mixing zone of the coagulation reactor with a first fluid. In one embodiment of the process, the latex of the second elastomer is in a reservoir separate from the reservoir containing the first latex. Another peristaltic pump continuously supplies the mixing zone of the coagulation reactor from this second reservoir. Thus, the mixing zone of the coagulation reactor is continuously supplied with the latex fluid from the first elastomer and continuously with the latex fluid from the second elastomer, both fluids having the same velocity, which is lower than the supply velocity of the second flow, consisting of the aqueous reinforcing filler dispersion comprising pyrolysis carbon black. In another embodiment, the continuous flow of the second latex elastomer is injected upstream of the outlet of the mixing zone of the coagulation reactor; that is, the second latex is injected into the flow of the coagulum that forms. An example of this embodiment is described in document WO20211034589, more specifically in paragraphs

[0029] to

[0067] .

[0120] Elastomeric composition

[0121] Another object of the present invention is an elastomeric composition comprising at least one coagulum as defined above, in particular a dry coagulum also called a masterbatch and at least one crosslinking system.

[0122] Thus, preferably the elastomeric composition according to the invention may comprise at least one crosslinking system and at least one master blend based on an elastomer, in particular dienic and preferably natural rubber, and at least one reinforcing filler comprising at least one pyrolysis black, said master blend being obtained by liquid mixing as explained above.

[0123] The crosslinking system may be any type of crosslinking system known to those skilled in the art in the field of elastomeric compositions. In particular, it may be based on sulfur, and / or peroxide, and / or bismaleimides.

[0124] Preferably, the crosslinking system is sulfur-based; this is referred to as a vulcanization system. The sulfur can be supplied in any form, including molecular sulfur or a sulfur-donating agent. At least one vulcanization accelerator is also preferably present, and optionally, various known vulcanization activators such as zinc oxide, stearic acid, or equivalent compounds such as stearic acid salts and transition metal salts, guanidine derivatives (in particular diphenylguanidines), or known vulcanization retardants may be used.

[0125] Sulfur is used at a preferential rate in the range of 0.5 to 12 parts per liter, in particular from 1 to 10 parts per liter. The vulcanization accelerator is used at a preferential rate of 0.5 to 10 parts per liter, more preferably from 0.5 to 5.0 parts per liter.

[0126] Any compound capable of acting as a vulcanization accelerator for elastomers, particularly diene elastomers, in the presence of of sulfur, including thiazole-type accelerators and their derivatives, sulfenamide-type accelerators, thiuram-type accelerators, dithiocarbamate-type accelerators, dithiophosphate-type accelerators, thiourea-type accelerators, xanthate-type accelerators and mixtures of these accelerators. Examples of such accelerators include the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds.

[0127] Elastomeric compositions according to the invention may also include all or part of the usual additives and processing agents known to those skilled in the art and commonly used in elastomeric compositions for pneumatic or non-pneumatic tires, in particular treads, such as plasticizers (such as plasticizing oils and / or plasticizing resins), fillers (reinforcing or non-reinforcing / (the same as those mentioned above or others than those mentioned above)), pigments, protective agents such as anti-ozone waxes, chemical anti-ozonants, antioxidants, anti-fatigue agents, reinforcing resins (such as described for example in application WO 02 / 10269).

[0128] The rubber composition according to the invention can be manufactured in suitable mixers, using two successive preparation phases well known to those skilled in the art: - a first thermomechanical working or mixing phase (the so-called "non-productive" phase), which can be carried out in a single thermomechanical step during which all the necessary constituents are introduced into a suitable mixer such as a standard internal mixer (for example, of the 'Banbury' type), i.e. the master mixture obtained by the process of the invention, any other possible reinforcing or non-reinforcing fillers, any other miscellaneous additives, with the exception of the crosslinking system.

[0129] The non-productive phase can be carried out at high temperature, up to a maximum temperature within a range of 110°C to 200°C, preferably from 130°C to 185°C, for a duration generally within a range of 2 to 10 minutes. - a second phase of mechanical work (the so-called "productive" phase), which is carried out in an external mixer such as a roller mixer, after cooling of the mixture obtained during the first non- productive down to a lower temperature, typically below 120°C, for example from 40°C to 100°C. The crosslinking system, preferably the vulcanization system, is then incorporated, and the whole is then mixed for a few minutes, for example from 5 to 15 min.

[0130] The final composition thus obtained can then be calendered, for example in the form of a sheet or plate, in particular for characterization in the laboratory, or extruded in the form of a semi-finished (or profile) elastomeric product usable, for example, as a tread for a pneumatic or non-pneumatic tire.

[0131] The composition can be either in the raw state (before crosslinking or vulcanization), or in the cooked state (after crosslinking or vulcanization), can be a semi-finished product that can be used in a tire.

[0132] The crosslinking of the composition can be carried out in a manner known to those skilled in the art, for example at a temperature in the range of 130°C to 200°C, under pressure.

[0133] Rubber article

[0134] Another object of the present invention relates to a rubber article comprising at least a coagulum as described above, preferably a dried coagulum or at least an elastomeric composition as defined above.

[0135] The rubber article can be any type of article such as a hose, a pipe, a sealing gasket, an O-ring, a transmission belt, an engine mount, an anti-vibration system, a window profile, a car body and window sealing profile, an insulator for electrical cables, a shoe sole, a rubber mat, a conveyor belt, a semi-finished article for pneumatic bandages, a semi-finished article for non-pneumatic bandages, a pneumatic bandage, a non-pneumatic bandage.

[0136] Preferably, the rubber article is chosen from the group consisting of semi-finished articles for pneumatic bandages, semi-finished articles for non-pneumatic bandages, pneumatic bandages and non-pneumatic bandages.

[0137] More preferably, the coagulum as defined above, more preferably the dry coagulum, or the elastomeric composition as defined above useful within the scope of the invention constitutes all or part of said semi-finished article.

[0138] More preferably, the coagulum as defined above, more preferably the dry coagulum, or the elastomeric composition as defined above useful within the scope of the invention constitutes all or part of the pneumatic bandage or the non-pneumatic bandage.

[0139] Semi-finished products for pneumatic or non-pneumatic bandages are rubber products intended for the manufacture of pneumatic bandages or non-pneumatic bands. This can be any type of rubber band, such as treads, underlayers, etc...top reinforcement plies (for example, working plies, protective plies or bracing plies), carcass reinforcement plies, sidewall plies, bead plies, protector plies, underlayer plies, rubber block plies and other plies ensuring the interface between the aforementioned areas of the tires.

[0140] Preferably, the semi-finished article for pneumatic or non-pneumatic tires can be chosen from the group consisting of treads, underlayers, working layers, protective layers, reinforcing layers, carcass reinforcement layers, sidewall layers, bead layers, protector layers; preferably can be a tread.

[0141] As is known, the tread of a pneumatic or non-pneumatic tire comprises a rolling surface intended to be in contact with the ground when the pneumatic or non-pneumatic tire is in motion. The tread is provided with a tread pattern comprising, in particular, tread elements or elementary blocks delimited by various main grooves, longitudinal or circumferential, transverse or oblique, the elementary blocks possibly also comprising various finer incisions or slits.

[0142] Advantageously, the coagulum(s) as defined above, preferably the dry coagulum(s), or the elastomeric composition as defined above useful within the scope of the invention, may be present in the tread of the pneumatic or non-pneumatic tire, preferably in the radially outer portion of the tread intended to be in contact with the ground when the tire rolls. More preferably still, the coagulum(s) as defined above, preferably the dry coagulum(s), or the elastomeric composition as defined above useful within the scope of the invention, may constitute all or part of the tread, particularly for pneumatic or non-pneumatic tires.

[0143] The term "pneumatic tire" refers to a tire designed to form a cavity by cooperating with a support element, for example a rim, this cavity being capable of being pressurized to a pressure greater than atmospheric pressure. A pneumatic tire usually comprises two beads intended to come into contact with a rim, a crown consisting of at least one crown reinforcement and a tread, two sidewalls, the tire being reinforced by a carcass reinforcement anchored in the two beads.

[0144] In contrast, a "non-pneumatic tire" is a tire that supports the load of a vehicle by means other than pressurized inflation gas. Thus, a non-pneumatic tire is a toroidal body made of at least one polymeric material, designed to perform the function of a tire but without being subjected to inflation pressure. A non-pneumatic tire can be solid or hollow. A hollow non-pneumatic tire can contain air, but at atmospheric pressure; that is, it does not have the pneumatic rigidity provided by inflation gas at a pressure higher than atmospheric pressure. A non-pneumatic tire usually comprises a base, designed, for example, for mounting on a rigid rim, a crown reinforcement, ensuring the connection with a tread, and a deformable structure such as spokes, ribs, or dimples, this structure being arranged between the base and the crown.Such non-pneumatic bandages do not necessarily include a flank. Non-pneumatic bandages are described, for example, in documents WO 03 / 018332 and FR2898077.

[0145] The pneumatic tires according to the invention can be intended to equip in particular vehicles of all types such as passenger vehicles, two-wheeled vehicles, industrial vehicles chosen from vans, heavy goods vehicles, subways, buses, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering vehicles, and all other transport or handling vehicles or aircraft or, more generally, on any rolling device.

[0146] The non-pneumatic tires according to the invention are intended to be fitted preferentially to passenger vehicles or two-wheeled vehicles.

[0147] EXAMPLES OF IMPLEMENTATION OF THE INVENTION

[0148] 1-Measures

[0149] 1-1- Measurement of the fatigue resistance of an elastomeric composition

[0150] An elastomeric composition can be characterized with respect to its resistance to cracking by a fatigue test. The fatigue resistance, expressed in number of cycles or in relative unit (percentage of a number of cycles relative to a reference number of cycles), is measured on 12 specimens subjected to repeated tensile stresses at a frequency of 1.75 Hz until an elongation of 75%, at a temperature of 23°C, using a Monsanto apparatus (type "MFTR") until the specimen breaks, applying the protocol described in ASTM D4482-85 and ISO 6943-2017 to dumbbell-shaped specimens known as B15 (78.5 mm long, 1.5 mm thick, 15 mm wide).

[0151] With results expressed in relative units, a value greater than that of a reference control, arbitrarily set at 100, indicates an improved result, i.e., better fatigue resistance of the elastomeric mixture samples. Correspondingly, a value below 100 indicates a degraded result, i.e., lower fatigue resistance of the elastomeric mixture samples.

[0152] 1-2 Dispersion

[0153] In a known manner, the charge dispersion in an elastomeric matrix can be represented by the Z note, which is measured, after crosslinking, according to the method described by S. Otto et al. in Kautschuk Gummi Kunststoffe, 58 Jahrgang, NR 7-8 / 2005, in accordance with ISO 11345.

[0154] The calculation of the Z score is based on the percentage of surface area in which the charge is not dispersed ("% undispersed surface"), as measured by the "disperGRADER+" device supplied with its operating instructions and "disperDATA" operating software by Dynisco according to the equation:

[0155] Z = 100 - (% undispersed area) / 0.35

[0156] The percentage of undispersed surface is measured using a camera observing the surface of the sample under incident light at 30°. Light spots are associated with filler and agglomerates, while dark spots are associated with the rubber matrix; digital processing transforms the image into a black and white image, and allows the determination of the percentage of undispersed surface, as described by S. Otto in the aforementioned document.

[0157] The higher the Z score, the better the dispersion of the charge in the elastomeric matrix (a Z score of 100 corresponds to perfect dispersion and a Z score of 0 to poor dispersion).

[0158] 2 - Manufacture of elastomeric compositions

[0159] 2.1- Obtaining compositions by bulk mixing:

[0160] The control compositions T1 and T2 to be tested are prepared as follows: natural rubber in solid form is introduced into an internal mixer, filled to 70% by volume and with an initial tank temperature of approximately 60°C, followed by either solid virgin carbon black or solid pyrolysis carbon black, to obtain a masterbatch (method a). The various other ingredients, with the exception of sulfur and the vulcanization accelerator, are then added to this masterbatch. Thermomechanical work (non-productive phase) is then carried out in one or two stages (total mixing time of approximately 3 to 6 minutes, until a maximum "drop" temperature of approximately 160-165°C is reached). The mixture thus obtained is collected, cooled, then sulfur and vulcanization accelerator are added on an external mixer (homo-finisher) at 40°C, mixing everything (productive phase) for 4 to 10 minutes.

[0161] The compositions T1 and T2 are then shaped for measurements of their physical or mechanical properties (for example in the form of test specimens) and if necessary baked (or vulcanized) for measurements of baked properties.

[0162] 2.2- Obtaining compositions from a master mixture obtained by mixing in liquid form:

[0163] Compositions T3 and Cl are obtained from a master mixture obtained by liquid mixing according to the process described in US6,929,783.

[0164] The elastomer used to obtain compositions T3 and Cl is a natural rubber in the form of latex and more particularly a natural field rubber with a dry mass concentration of 34.2%.

[0165] Carbon blacks are used in the form of an aqueous dispersion prepared at a mass concentration of 15.5%, whether for virgin carbon black or for pyrolysis carbon black, by mixing solid virgin carbon black or solid pyrolysis carbon black (in dry powder form) in deionized water and under agitation.

[0166] The aqueous dispersion of virgin carbon black for composition T3 or pyrolysis carbon black for composition Cl is sent at a mass flow rate of 175 kg / h through a progressive gravity pump (Noy Mono single-series W range Widethroat pump) to the grinder (IKA DR2000 / 10 grinder) and then to the high-pressure homogenizer (GEA Niro Soavi Ariete NS 3015H) which operates at an inlet pressure of 200 bar.

[0167] The aqueous dispersion of carbon black exiting the homogenizer is injected into the mixing zone of the coagulation reactor at a mass flow rate of 175 kg / h and coagulates with the rubber latex also fed into this mixing zone at a mass flow rate of 125 kg / h. The coagulation reactor is that described in columns 14 to 16 of US patent 6,929,783 and columns 14 to 21 of US patent 6048923.

[0168] At the outlet of the coagulation reactor, a coagulum (also called "worms / crumb" in English) is obtained which is sent to a single screw extruder (also called a drying spinner or "dewatering extruder" in English).

[0169] At the outlet of the drying centrifuge, the drained coagulum, which has approximately 22% moisture content by weight relative to the total weight of the drained coagulum, is sent to a continuous reactor equipped with two axial rotors (Kobelco KTX-46 twin-screw extruder). The double jacket temperature of this continuous reactor is 140°C, it operates at a speed of 175 rpm, and the output flow rate is 836 g / min. The coagulum is then sent to the roller tool (ME 400 roller tool, Lescuyer) which has a 2.5 mm air gap, a coefficient of friction of 0.9, and operates at a speed of 20 m / min.

[0170] Upon exiting the roller tool, the coagulum is dry (moisture content less than 1% by weight of the total weight of the coagulum) and can be used as a masterbatch for the manufacture of T3 and CL elastomeric compositions

[0171] The masterbatch obtained previously is introduced into an internal mixer, filled to 70% by volume, with an initial tank temperature of approximately 60°C. The various other ingredients, with the exception of sulfur and the vulcanization accelerator, are then added to this masterbatch. A thermomechanical process (non-productive phase) is then carried out in one or two stages (total mixing time of approximately 3 to 6 minutes, until a maximum "drop" temperature of approximately 160-165°C is reached). The resulting mixture is collected, cooled, and then sulfur and the vulcanization accelerator are added to an external mixer (homo-finisher) at 40°C, with the mixture being blended (productive phase) for 4 to 10 minutes.

[0172] The T3 and Cl compositions are then shaped for measurements of their physical or mechanical properties (for example in the form of test specimens) and if necessary baked (or vulcanized) for measurements of baked properties.

[0173] 3 Example 1

[0174] This test aims to highlight an improvement in the fatigue resistance properties of an elastomeric composition (composition Cl according to the invention) based on a master mixture comprising at least one pyrolysis carbon black, said master mixture being obtained according to the process of the invention.

[0175] The formulations of the tested compositions are presented in Table 1. The quantities are expressed in wt. (parts by weight per hundred parts by weight of elastomer). [Table 1]

[0176] [Tables] Tl T2 T3 Cl Natural Rubber 100.0 (a) 100.0 (a) 100.0 (b) 100.0 (b) Virgin Carbon Black (1) 50.0 (a) 50.0 (b) Pyrolysis Carbon Black (2) 50.0 (a) 50.0 (b) Antioxidant (3) 2.0 2.0 2.0 2.0 Stearic Acid (4) 2.5 2.5 2.5 2.5 Zinc Oxide (5) 2.7 2.7 2.7 2.7 Vulcanization Accelerator (6) 0.7 0.7 0.7 0.7 Sulfur 1.7 1.7 1.7 1.7

[0177] (1) Virgin carbon black of grade N134 according to ASTM D1765-17, (rate Ash content measured according to the method described above: 0.44%; sulfur content measured according to the method described above: 0.57%; zinc content: 221 ppm (ppm: parts per million) (these percentages are weight percentages relative to the weight of virgin carbon black). This carbon black is produced from raw materials non-recycled petroleum-based liquids and is commercially available from Orion, Cabot, etc.

[0178] (2) “P550” pyrolysis carbon black from Scandinavian Enviro Systems (Ash content measured according to the method described above: 18.5%; sulfur content measured according to the method described above: 3%; zinc content: 4.5% (percentages are weight percentages relative to the weight of pyrolysis carbon black); STSA specific surface area: 56 m² / g (ASTM D6556-2021); void volume at 50 MPa: 44 ml / 100 g (ASTM D7854-21)). This pyrolysis carbon black is produced from end-of-life tires that are pyrolyzed.

[0179] (3) N-cyclohexyl-2-benzothiazyl-sulfenamide marketed by Flexys under the reference “Sancure CBS”

[0180] (4) Stearine marketed by the company Uniquema under the name " Pristerene 4931 »

[0181] (5) Industrial grade zinc oxide

[0182] (6) N-cyclohexyl-2-benzothiazyl-sulfenamide marketed by Flexys under the reference “Sancure CBS”

[0183] (a) natural rubber and virgin carbon black or carbon black of pyrolysis products are mixed by mass as explained in paragraph 2.1 below

[0184] (b) natural rubber and virgin carbon black or carbon black of pyrolysis products are mixed in liquid form as explained in paragraph 2.2 below.

[0185] The properties of the compositions T1, T2, T3 and Cl measured after heating at 150°C for 15 min are reported in Table 2. [table 2]

[0186] [Tables2] Tl T2 T3 Cl Note Z 51 38 92 68 Fatigue resistance, on a scale of 100 100 26 115 80

[0187] Replacing virgin carbon black with pyrolysis carbon black leads to a significant decrease in the fatigue strength of the control composition T2 compared to the control composition TL. A low dispersion of pyrolysis carbon black is also observed in composition T2.

[0188] The use of the liquid-based mixing technique (composition T3) instead of bulk-based mixing (composition Tl) leads to a significant improvement in the fatigue resistance of the control composition T3 compared to the control composition TL

[0189] Unexpectedly, the incorporation by liquid mixing of pyrolysis carbon black makes it possible to obtain an elastomeric composition (composition Cl according to the invention) exhibiting good dispersion of the pyrolysis carbon black and a significantly improved fatigue resistance property compared to an elastomeric composition in which pyrolysis carbon black is conventionally incorporated by bulk mixing (control composition T2). While the use of a masterbatch obtained by liquid mixing does improve the fatigue resistance of an elastomeric composition with virgin carbon black, as shown by the comparison of compositions T1 / T3, when using pyrolysis carbon black (composition Cl), this improvement is significantly greater than the sum of the effects obtained by replacing virgin carbon black with pyrolysis carbon black (comparison T1 / T2) and by replacing bulk mixing with liquid mixing (comparison T1 / T3).The elastomeric composition of invention C2 exhibits good dispersion of pyrolysis carbon black and maintenance of mechanical properties while limiting the environmental impact of manufacturing this composition.

[0190] 4 Example 2

[0191] This test aims to highlight an improvement in the fatigue resistance properties of an elastomeric composition based on 60 pce of carbon black in a master mix obtained by liquid mixing.

[0192] The formulations of the tested compositions are presented in Table 3. The quantities are expressed in parts per cent (parts by weight per hundred parts by weight of elastomers). [Table 3]

[0193] [Tables3] T4 T5 T6 C2 Natural Rubber 100.0 (a) 100.0 (a) 100.0 (b) 100.0 (b) Virgin Carbon Black (1) 60.0 (a) 60.0 (b) Pyrolysis Carbon Black (2) 60.0 (a) 60.0 (b) Antioxidant (3) 2.0 2.0 2.0 2.0 Stearic Acid (4) 2.5 2.5 2.5 2.5 Zinc Oxide (5) 2.7 2.7 2.7 2.7 Vulcanization Accelerator (6) 0.7 0.7 0.7 0.7 Sulfur 1.7 1.7 1.7 1.7

[0194] Ingredients (1) to (6) are identical to those in Table 1.

[0195] (a) natural rubber and ASTM grade virgin carbon black or black of pyrolysis carbons are mixed by mass as explained in paragraph 2.1 above.

[0196] (b) natural rubber and ASTM grade virgin carbon black or black of pyrolysis carbons are mixed in liquid form as explained in paragraph 2.2 above.

[0197] Compositions T4 and T5 are prepared in the same way as compositions T1 and T2 and according to the process described in 2.1.

[0198] Compositions T6 and C2 are prepared in the same way as compositions T3 and Cl and according to the process described in 2.2 by adjusting the values ​​of the slurry of pyrolysis carbon black to have the correct rate of pyrolysis carbon black in the coagulum.

[0199] The properties of compositions T4, T5, T6 and C2 measured after cooking at 150°C for 15 min are reported in Table 4. [table 4]

[0200] [Tables4] T4 T5 T6 C2 Note Z 57 38 92 69 Fatigue resistance, on a scale of 100 100 23 120 99

[0201] As with example 1, it is unexpectedly observed that, with a rate of 60 pc of pyrolysis carbon black, a composition C2 (according to the invention) is obtained which exhibits good dispersion of pyrolysis carbon black and improved fatigue resistance which is greater than the sum of the effects obtained by replacing virgin carbon black with pyrolysis carbon black (comparison T4 / T5) and by replacing bulk mixing with liquid mixing (comparison T4 / T6).

Claims

Demands

1. A method for continuously obtaining a coagulum based on at least one elastomer and a reinforcing filler, said method comprising the following steps: a. continuously supplying a first stream of a fluid consisting of an elastomer latex, b. continuously supplying a second stream of a fluid consisting of an aqueous dispersion of a reinforcing filler comprising at least one pyrolysis carbon black, c. bringing said first stream into contact with said second stream in a mixing zone of a coagulation reactor, the continuous contact inducing the formation of a coagulum of the elastomer latex with the aqueous dispersion of the reinforcing filler, d. continuously recovering said coagulum obtained in the preceding step.

2. A method for continuously obtaining a coagulum according to the preceding claim, wherein the pyrolysis carbon black has an ash content in the range of 5% to 30% by weight, more preferably from 8% to 25% by weight, more preferably from 10% to 22% by weight, relative to the total weight of the pyrolysis carbon black.

3. A method for continuously obtaining a coagulum according to any one of the preceding claims, wherein the pyrolysis carbon black has a sulfur content greater than 2% by weight, preferably in the range of 2.5% to 5% by weight, relative to the total weight of the pyrolysis carbon black.

4. A method for continuously obtaining a coagulum according to any one of the preceding claims, wherein the pyrolysis carbon black has a zinc content greater than or equal to 2% by weight, preferably in the range of 2.5% to 8% by weight, relative to the total weight of the pyrolysis carbon black.

5. A method for continuously obtaining a coagulum according to any one of the preceding claims, wherein the elastomer is a diene elastomer.

6. A method for continuously obtaining a coagulum according to any one of the preceding claims, wherein the elastomer is chosen from the group consisting of natural rubber, polybutadienes, synthetic polyisoprenes, butadiene copolymers, isoprene copolymers and mixtures of these elastomers, preferably the elastomer is natural rubber.

7. A method for continuously obtaining a coagulum according to any one of the preceding claims, wherein the aqueous reinforcing filler dispersion comprises at least one second reinforcing filler other than pyrolysis carbon black; the second reinforcing filler being selected from the group consisting of virgin carbon blacks, silicas and mixtures of these reinforcing fillers.

8. A method for continuously obtaining a coagulum according to any one of the preceding claims, wherein the pyrolysis carbon black represents more than 50% by weight, more preferably more than 70% by weight, more preferably more than 90% by weight of the total weight of the reinforcing filler.

9. A method for continuously obtaining a coagulum according to any one of the preceding claims, wherein the contacting of step c) is carried out with the following steps: i. supplying the continuous flow of the first elastomer latex fluid to a mixing zone of a coagulation reactor defining an elongated coagulation zone extending between the mixing zone and an outlet, ii. supplying the continuous flow of the second fluid of the pressurized aqueous dispersion to the mixing zone of a coagulation reactor to form the coagulum.

10. A method for continuously obtaining a coagulum according to any one of the preceding claims, further comprising at least one continuous drying step to obtain a coagulum

11. □CC. Coagulum obtained according to the process as defined in any one of claims 1 to 10, preferably obtained according to the process of claim 10.

12. Elastomeric composition comprising at least one coagulum as defined in claim 11 and at least one crosslinking system.

13. Rubber article comprising at least one coagulum as defined in claim 11 or at least one elastomeric composition as defined in claim 12, preferably the rubber article is a semi-finished product for pneumatic or non-pneumatic bandage or a pneumatic or non-pneumatic bandage.

14. Semi-finished product for pneumatic or non-pneumatic tire according to claim 13, the semi-finished product being selected from the group consisting of treads, underlayers, working plies, protective plies, reinforcing plies, carcass reinforcement plies, sidewall plies, bead plies, protector plies; preferably being a tread.