Process for the production of hydrocarbon resins from polystyrene residues and tire residues

Abstract

The invention relates to a process for producing hydrocarbon resins from the microwave-assisted pyrolysis of a feedstock of styrene compounds and a feedstock comprising rubber chips, to the resin produced by said process, and to a rubber composition comprising a resin of said kind.

Description

[0001] Process for the production of hydrocarbon resins from polystyrene residues and tire residues

[0002] Technical field of the invention

[0003] The present invention relates to the field of processes for producing hydrocarbon resins from recycled residues, to the resins produced by such processes as well as to the compositions comprising these resins, in particular the compositions intended for rubber articles and in particular vehicle tires.

[0004] Prior art

[0005] Tires, and more generally rubber products such as conveyor belts and non-pneumatic tires, are complex objects made up of a multitude of components. For example, a tire is made up of more than 200 different raw materials, including different families of elastomers, reinforcing fillers, oils, and hydrocarbon resins.

[0006] Within hydrocarbon resins, hydrocarbon resins with a high glass transition temperature (Tg) comprising both aliphatic and aromatic functions are used to shift the performance compromises of the mixtures, such as rolling resistance or grip. These resins make it possible, in particular, to modify the Tg of the mixture. Such resins with a high Tg are known from the state of the art and described, for example, in documents WO2016 / 043851, US9139721 or FR2968006.

[0007] The compatibility of resins with the elastomeric matrix, and in particular their ability to disperse correctly in the mixture, is essential for them to play their role correctly. The compatibility of the resin with an elastomeric matrix depends, among other things, on properties such as the glass transition temperature and the softening point of the resin, these properties being dependent on the molar mass, the nature and the ratio of aromatic units to aliphatic units of the resin (see for example J. Appl Polym. Sci 2022 139(15) 51950). It is therefore important to be able to vary these parameters in order to address the variety of elastomers used in rubber compositions.Such resins comprising aliphatic and aromatic units are well known in the state of the art, for example in document EP 0 936 229 which teaches the manufacture of hydrocarbon resins from aliphatic and aromatic monomers in cationic polymerization, from petroleum-sourced streams. If the performance of tires such as rolling resistance and wear resistance are key to limiting the environmental impact of these tires, it is also important to seek to limit as much as possible the use of fossil resources during the manufacture of rubber articles.

[0008] Document US2013 / 0281611 describes a rubber composition for a tire that includes a plasticizer derived from the recycling of waste, the plasticizer being used here as a substitute for process oils. Documents WO2022 / 101562 and WO2022 / 101563 describe the production of hydrocarbon resins from residues from the pyrolysis of rubber chips. However, these documents do not address the issue of adjusting the microstructure of the resins, and in particular the adjustment of the level of aromatic and aliphatic monomers.

[0009] Thus, an object of the present invention is to provide a process for producing resins that can be incorporated into a wide variety of elastomeric compositions from bio-sourced and / or recycled resources.

[0010] Detailed description of the invention

[0011] The invention relates to at least one method for producing hydrocarbon resins from a feedstock of styrenic compounds and a feedstock comprising rubber chips, said method comprising at least ■ a. A step of preparing the feedstock of styrenic compounds so as to be able to feed this feedstock into the pyrolysis step; bl. A step of microwave pyrolysis of the feedstock of styrenic compounds making it possible to obtain at least one gaseous effluent and one pyrolysis oil, said gaseous effluent comprising at least 20% by weight of aromatic compounds cl. A step of separating the gaseous effluent from step bl) into at least one stream rich in light compounds, one stream rich in aromatics and one stream rich in heavy compounds b2.A step of microwave pyrolysis of the feedstock comprising rubber chips carried out at a temperature between 300 and 900°C, making it possible to obtain a gaseous effluent, a pyrolysis oil and a solid effluent, said pyrolysis oil comprising at least 1.5% by weight of C4-C12 olefinic monomers; c2. A step of separation of the pyrolysis oil resulting from step b2) into at least one raffinate, an intermediate fraction and an extract, the intermediate fraction having a boiling point at atmospheric pressure in the range from 140 to 280°C and comprising at most 10% by weight of heteroatoms d. A step of synthesis of resins comprising a polymerization section supplied at least by a flow resulting from step c1) and by the intermediate fraction resulting from step c2), followed by a finishing section and producing a polymerized effluent e.A treatment step comprising a section for separating the polymerized effluent from step d) into a solvent-rich effluent and a resin-rich effluent, and a drying section fed with the resin-rich effluent in order to produce a stream of hydrocarbon resins.

[0012] Preferably, the charge of styrenic compounds is a charge of styrenic compounds derived from plastic waste comprising at least 90% by weight of polystyrene.

[0013] Preferably, the rubber chips comprise at least 50 pce of diene elastomer, preferably at least 60 pce of diene elastomer.

[0014] Preferably, the charge of styrenic compounds is gradually heated during step a) to a temperature between 100°C and 300°C, preferably between 150°C and 300°C and preferably between 200°C and 300°C.

[0015] Preferably, the pyrolysis step b1) comprises a pyrolysis reactor operated at a temperature ranging from 300°C to 900°C and preferably from 300 to 800°C and a pressure ranging from 0.8 bar to 7.5 bar.

[0016] Preferably, separation step cl) is carried out by distillation.

[0017] Preferably, the mass ratio of flow from step cl) to the intermediate fraction from step c2) feeding step d) is adjusted so that the resin obtained has a molar ratio of aliphatic H to aromatic H ranging from 40 / 60 to 95 / 5, preferably ranging from 50 / 50 to 90 / 10, preferably ranging from 55 / 45 to 90 / 10.

[0018] Preferably, the polymerization section of resin synthesis step d) is also supplied with a solvent stream chosen from aliphatic, aromatic, halogenated solvents and their mixtures.

[0019] In a preferred arrangement, the process according to the invention is fed only by the feedstock of styrenic compounds and the feedstock comprising rubber chips, the solvent required in step d) being provided by at least one stream from step c2) and / or at least a fraction of the pyrolysis oil from step b1). Preferably, in this arrangement, at least a fraction of the pyrolysis oil from step b1) feeds step d) of resin synthesis.

[0020] Definitions

[0021] The carbon-containing compounds mentioned in the description may be of fossil or bio-sourced origin. In the latter case, they may be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass.

[0022] A Cn compound means a compound containing n carbon atoms. Similarly, a Cn'Cm compound means a set of compounds containing n to m carbon atoms.

[0023] A heteroatom is an atom other than carbon or hydrogen, for example nitrogen, sulfur, oxygen.

[0024] A hydrocarbon compound means a compound consisting of carbon and hydrogen.

[0025] Process load

[0026] The process according to the invention is a process for producing hydrocarbon resins from a charge of styrenic compounds and a charge comprising rubber chips. These two charges are derived from the recycling of materials, for example polystyrene objects and end-of-life vehicle tires, or from manufacturing residues that are not used or do not conform to the use for which they were intended.

[0027] Styrenic compound filler means a filler that includes styrene-based polymers, such as styrenic rubbers and polystyrene.

[0028] Preferably, the filler of styrenic compounds is a filler of styrenic compounds derived from plastic waste. Such a filler preferably comprises at least 90% by weight of polystyrene, preferably at least 93% by weight of polystyrene, and more preferably at least 95% by weight of polystyrene. The filler of styrenic compounds may comprise other compounds, in particular if it is derived from plastic waste. These other compounds may be, in a non-limiting manner, plastic compounds such as polyethylene, polypropylene, elastomers, organic materials such as paper, food, or inorganic materials such as glass, metal, sand. By chip is meant a small element obtained by cutting rubber articles, preferably rubber articles at the end of their life.The rubber articles are preferably stripped of their non-rubber constituent elements, such as for example textile fibers or metal wires. The rubber chips preferably have a greater length ranging from 1 to 100 mm, preferably from 1 to 50 mm and most preferably from 1 to 30 mm. The chips can have any shape, but chips of relatively uniform size and shape will be preferred in order to facilitate the conduct of the pyrolysis step. This control of size and shape is well known to those skilled in the art.

[0029] Preferably, the rubber chips comprise at least 50 pce of diene elastomer. By "diene" elastomer (or indistinctly rubber), whether natural or synthetic, is meant in a known manner an elastomer consisting at least in part (i.e., a homopolymer or a copolymer) of diene monomer units (monomers carrying two carbon-carbon double bonds, conjugated or not).

[0030] Preferably, the diene elastomer is chosen from the group consisting of polybutadienes (BR), natural rubber (NR), synthetic polyisoprenes (IR), butadiene copolymers, isoprene copolymers, and blends of these elastomers. Butadiene copolymers are particularly chosen from the group consisting of butadiene-styrene copolymers (SBR).

[0031] Preferably, the diene elastomer is an isoprene elastomer.

[0032] The term "isoprene elastomer" is understood to mean, in a known manner, a homopolymer or copolymer of isoprene, in other words a diene elastomer chosen from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), various isoprene copolymers and mixtures of these elastomers. Among the isoprene copolymers, mention may be made in particular of isobutene-isoprene (butyl rubber - IIR), isoprene-styrene (SIR), isoprene-butadiene (BIR) or isoprene-butadiene-styrene (SBIR) copolymers. This isoprene elastomer is preferably chosen from the group consisting of natural rubber, synthetic cis-1,4 polyisoprenes and their mixtures among these synthetic polyisoprenes, preferably polyisoprenes having a rate (mol%) of cis-1,4 bonds greater than 90%, more preferably still greater than 98%.Preferably and according to any of the arrangements herein, the diene elastomer is natural rubber. A high content of diene elastomer promotes the production of monomers of interest at the pyrolysis outlet, in particular limonene.

[0033] Preferably, the rubber chips come from tire treads, in particular from heavy goods vehicle tire treads, the latter having high contents of diene elastomers, preferably isoprene, typically 60 to 100 pce of isoprene elastomers.

[0034] Step a) preparation

[0035] The method according to the invention comprises a step of preparing the charge of styrenic compounds. During this step, the charge of styrenic compounds is conditioned to be able to feed the pyrolysis step b). This preparation step may comprise operations of grinding, degassing, heating in order to cause the melting of the plastic compounds, for example in an extrusion device during which the temperature is gradually increased, the vapor effluents (water, light compounds generated by the partial decomposition of the polystyrenic charge) and the solid effluents (non-fusible debris such as metal debris, glass) are separated.

[0036] Preferably, the charge of styrenic compounds is gradually heated to a temperature between 100°C and 300°C, preferably between 150°C and 300°C and more preferably between 200°C and 300°C, this temperature making it possible to obtain the melting of the polystyrene, when such a compound is present, by limiting its thermal decomposition.

[0037] Step bl) of pyrolysis of the charge of styrenic compounds

[0038] The charge of styrenic compounds feeds a pyrolysis step making it possible to obtain at least one gaseous effluent and one pyrolysis oil, said pyrolysis oil comprising at least 20% by weight of aromatic compounds.

[0039] Pyrolysis means the thermal decomposition of compounds in an inert or oxygen-deficient atmosphere, i.e. comprising less than 5% by volume, preferably less than 3% by volume and more preferably less than 2% by volume of oxygen, preferably in an inert atmosphere.

[0040] The feedstock is fed to a pyrolysis step, carried out at a temperature and pressure such that the depolymerization of the styrenic compounds into styrene oligomers and styrene monomer takes place. Preferably, the pyrolysis step is carried out at a temperature ranging from 300 to 900°C, preferably from 300°C to 800°C.

[0041] The pyrolysis step is preferably carried out at a pressure ranging from 0.8 bar to 7.5 bar, preferably ranging from 1 bar to 6 bar and more preferably ranging from 1 bar to 4.5 bar.

[0042] The pyrolysis step of the process according to the invention implements a microwave pyrolysis step. Such microwave pyrolysis usable for the pyrolysis of a charge of styrenic compounds is for example described in document WO 2020 / 202089.

[0043] Using a microwave-assisted pyrolysis step allows for higher heat transfer rates and reaction temperatures, which promote end-of-pipe scission reactions and minimize the formation of styrene oligomers. A microwave pyrolysis step is also characterized by a lower temperature in the reaction mass than a conventional pyrolysis section. The lower temperatures in the reaction mass result in lower styrene oligomer evaporation rates and help avoid over-cracking the styrene product. Using a microwave pyrolysis step will reduce the formation of styrene oligomers compared to a conventional pyrolysis step.

[0044] The pyrolysis step produces at least an off-gas and a pyrolysis oil. The off-gas may also contain entrained liquid droplets. In addition to styrene oligomers, the off-gas includes the majority of the styrene monomer produced in the pyrolysis step, as well as gaseous light aromatic compounds under operating conditions such as alpha-methyl-styrene, ethylbenzene, cumene, and toluene.

[0045] The gaseous effluent comprises at least 20% by weight of aromatic compounds, preferably at least 20% by weight of styrene.

[0046] Preferably, the gaseous effluent comprises at most 10% by weight of ethylbenzene, preferably at most 5% by weight of ethylbenzene and preferably at most 3% by weight of ethylbenzene.

[0047] Preferably, the gaseous effluent comprises at least 10% by weight of compounds whose boiling point is higher than that of styrene. The pyrolysis oil may also comprise solid elements, unfused polymers, produced during pyrolysis, or debris not separated in the feedstock preparation step. This flow preferably feeds a separation section in which the possible solid fraction is separated from the liquid fraction, the latter being able to be recycled in a mixture with the feed for the pyrolysis step or used in step d) of resin synthesis.

[0048] The pyrolysis step can be carried out in a pyrolysis reactor, and can be operated continuously, semi-continuously or in batch processing. Such reactors are well known to those skilled in the art.

[0049] Step cl) of separation of the gaseous effluent from step bl)

[0050] The process according to the invention comprises a separation step supplied at least with the gaseous effluent from step b1) and producing at least one stream rich in light compounds, one stream rich in aromatics and one stream rich in heavy compounds.

[0051] The stream rich in light compounds mainly comprises compounds lighter than benzene, in particular hydrogen, methane, ethane, ethylene, propane, propylene, butane, butene, isobutane.

[0052] The aromatic-rich stream comprises predominantly aromatic compounds comprising 6 to 9 carbon atoms. The separation step cl) is carried out in such a way that the aromatic-rich stream comprises at least 99% by mass of styrene.

[0053] The flow rich in heavy compounds mainly comprises non-depolymerized styrenic compounds, and in particular styrene oligomers when the feed comprises polystyrene.

[0054] Preferably, separation step cl) is carried out by distillation.

[0055] In a first variant of this preferred arrangement, a first column fed with the gaseous effluent from step b1) separates this effluent into a stream rich in light compounds and a raffinate, the latter being separated by means of a second column into a stream rich in aromatics and a stream rich in heavy compounds.

[0056] In a second variant of this preferred arrangement, the separation is carried out in a single distillation column. In this variant, at the top of the column, the vapor effluent is cooled to a temperature between 30°C and 50°C, preferably between 35°C and 45°C. The condensed liquid fraction is returned to the top of the column as reflux, while the vapor fraction is then subcooled to a temperature between -5°C and 10°C, preferably between -5°C and 5°C in order to condense any styrene entrained with the light compounds. The condensed stream after subcooling is returned to the top of the column as reflux. The residual vapor fraction constitutes the stream rich in light compounds. This stream can then be recovered, for example in the form of energy.A first cooling allows maximum use of cooling water at ambient temperature as cold utility and minimizes the use of specific cold utility to obtain sub-cooling, which has a favorable impact on the life cycle analysis of the process according to the invention.

[0057] In this variant, the distillation column is operated at a pressure of between 0.1 and 2.0 bara, preferably between 0.5 and 1.5 bara and more preferably between 0.5 and 1.1 bar, the operating pressure being understood as the pressure measured at the top of the column. By "bara" is meant absolute bar, as opposed to a pressure expressed in relative bar, commonly noted "barg" according to the English notation "bar gauge".

[0058] In this variant and preferably, the distillation column is fed at the bottom of the column with at least the gaseous effluent from step b1) and produces at the top of the column a flow rich in light compounds, at the bottom a flow rich in heavy compounds, and by a lateral withdrawal a flow rich in aromatics, said column having as its only heat input said gaseous effluent from step b1).

[0059] The gaseous effluent from step b1) is at high temperature, preferably at a temperature above 300°C. This temperature is sufficient so that the column does not require any further heat input.

[0060] By feeding the feedstock at the bottom of the column, the feedstock is rapidly cooled, thus limiting any potential styrene polymerization reactions. This feedstock also allows for better management of so-called heavy compounds. Indeed, the absence of a recirculation system at the bottom of the column, usually used to maintain the temperature of the distillation column, greatly limits the risks of fouling by so-called heavy compounds, which are particularly viscous. The distillation column used in this variant of step c1) of the process according to the invention comprises from 5 to 20 theoretical stages, preferably at most 15 theoretical stages, more preferably from 8 to 12 theoretical stages.

[0061] A stream rich in aromatics is withdrawn onto an intermediate tray. This withdrawal tray is located in the lower third of the distillation column, preferably 1 to 3 theoretical stages from the bottom tray. This withdrawal at a low position in the column, slightly removed from the bottom tray, limits the entrainment of heavy compounds in the stream rich in aromatics and thus limits the risk of fouling subsequent equipment.

[0062] Preferably, and in order to further limit the risk of polymerization, a styrene polymerization inhibitor to polystyrene, such as 2,2,6,6 _ tetramethyl-4-oxopiperidinooxy, may be fed into the distillation column of step c), or the distillation columns of step c) of the process, preferably at the column head.

[0063] Toluene and ethylbenzene type compounds, which do not react in step d) of resin synthesis, can be used as solvent in this synthesis step, which makes it possible to avoid the addition of a solvent of external origin to the process.

[0064] Step b2) of pyrolysis of the charge comprising rubber chips

[0065] The feedstock comprising rubber chips feeds a rubber chip pyrolysis step carried out at a temperature between 300 and 900°C, making it possible to obtain a gaseous effluent, a pyrolysis oil and a solid effluent, said pyrolysis oil comprising at least 1.5% by weight of C Cia olefinic monomers.

[0066] The pyrolysis step is preferably carried out at a temperature between 350 and 800°C, and preferably between 350 and 650°C, a pressure of less than 1 bar and a ratio of the residence time of the solid to the residence time of the gas ranging from 10 to 240, preferably from 10 to 120 and very preferably from 10 to 60.

[0067] A short residence time of the gas fraction compared to the residence time of the solid fraction improves the yield of monomers of interest. The residence time of the gas fraction can be reduced by feeding the pyrolysis step with an inert gas. This preferential feeding also improves the desorption of volatile matter bound to the solid fraction. The residence time of the solid fraction in the pyrolysis step preferably ranges from 3 to 180 min, preferably from 3 to 120 min. The residence time of the gas fraction is less than 3 min.

[0068] These particular conditions make it possible to maximize the production of compounds of interest, in particular monomers such as limonene, as well as gaseous fractions that can be used as fuels and heavy liquid fractions that can be used for the production of carbon black.

[0069] The pyrolysis step can be carried out in a pyrolysis reactor, and can be operated continuously, semi-continuously or in batch processing. Such reactors are well known to those skilled in the art.

[0070] The pyrolysis step implements a microwave pyrolysis step. Such microwave pyrolysis usable for the pyrolysis of a feedstock comprising rubber chips is for example described in the documents Journal of Analytical and Applied Pyrolysis 123 (2017) 152-159, Energy 127 (2017) 571-580 and Journal of Analytical and Applied Pyrolysis 155 (2021) 104979.

[0071] The use of a microwave-assisted pyrolysis step allows for higher heat transfer rates and reaction temperatures, thanks in particular to the good thermal conductivity of the carbon black and metal oxides present in the composition. This improved transfer promotes end-of-chain scission reactions, resulting in better selectivity for compounds of interest, such as limonene, and minimizes the formation of oligomers, particularly higher isoprene oligomers when natural rubber is used in the rubber chips composition. A microwave pyrolysis step is also characterized by a lower and more homogeneous temperature in the reaction mass than a conventional pyrolysis section. The lower temperatures in the reaction mass lead to lower evaporation rates of the oligomers and help avoid “over-cracking” the limonene produced.The use of a microwave pyrolysis step will reduce the formation of isoprene oligomers and very light compounds compared to a conventional pyrolysis step.

[0072] The pyrolysis effluent is cooled so as to condense the volatile fractions. At the end of the condensation, three effluents are obtained: ■ a gaseous effluent comprising the incondensable gases (i.e. gaseous under normal temperature and pressure conditions, namely 0°C and 1 atm), a liquid effluent referred to as "pyrolysis oil" and a solid effluent.

[0073] Pyrolysis oil consists primarily of a mixture of hydrocarbons with a wide boiling point range. Most of these compounds are members of the alkane, olefin, naphthenes (cycloalkanes), and aromatic families. Some species containing heteroatoms are also present.

[0074] The operating conditions of the pyrolysis step of the process according to the invention make it possible to obtain a pyrolysis oil comprising at least 1.5% by weight of C4'Ci2 olefinic monomers, preferably at least 2% by weight of C Cia olefinic monomers, preferably at least 4% by weight.

[0075] Olefinic monomers are hydrocarbon compounds comprising unsaturated carbon-carbon bonds and capable of polymerizing under suitable conditions. These olefinic monomers include limonene, terpenes, aromatic olefins such as styrene, alpha-methylstyrene, indene, coumarone, linear or cyclic olefins such as dicyclopentadiene.

[0076] The pyrolysis oil preferably comprises at least 70% by weight of carbon element, preferably at least 74% by weight and preferentially at least 78% by weight.

[0077] The pyrolysis oil preferably comprises at most 5% by weight of nitrogen element, preferably at most 3% by weight and preferentially at most 1.5% by weight.

[0078] The pyrolysis oil preferably comprises at most 2% by weight of sulfur element, preferably at most 1.5% by weight and preferentially at most 1% by weight.

[0079] Step c2) of separation of the oil from step b2)

[0080] The process according to the invention comprises a step of separating the pyrolysis oil from step b2) into at least one raffinate, an intermediate fraction and an extract, the intermediate fraction having a boiling point at atmospheric pressure in the range from 140 to 280°C and comprising at most 10% by weight of heteroatoms.

[0081] The boiling point at atmospheric pressure can be determined in a manner known to those skilled in the art, for example by following the requirements of standard ASTM D86-23. Extract means a lighter fraction, i.e. one whose final boiling point (or cut point according to the terminology used in distillation) is lower than the intermediate fraction. Raffinate means a heavier fraction, i.e. one whose final boiling point is higher than the intermediate fraction.

[0082] The separation step makes it possible to eliminate from the pyrolysis oil the constituents which could be detrimental to the proper functioning of the resin synthesis step, in particular with regard to the activity of the catalyst.

[0083] Preferably, the intermediate fraction from step b2) is a cut whose boiling point at atmospheric pressure is in the range from 150 to 280°C and preferably from 150 to 260°C. This cut concentrates most of the olefinic monomers of interest, while excluding most of the compounds which may have a negative impact on the resin synthesis step.

[0084] Said intermediate fraction comprises at most 10% by weight of heteroatoms. In particular, it comprises limonene and other compounds of the terpene family, such as crpinene, B-pinene, carene, myrcene, farnesene, other oxidized or non-oxidized terpenes, aromatic olefins such as styrene, alpha-methyl-styrene, indene, coumarone, linear and cyclic olefins such as dicyclopentadiene, but also compounds inert with respect to the resin synthesis step such as aliphatic and aromatic hydrocarbons.

[0085] Preferably, the intermediate fraction resulting from step b2) comprises at most 2% by weight of sulfur element, preferably at most 1.5% by weight, and preferably less than 1% by weight, very preferably less than 0.8% by weight, the latter being particularly detrimental to the subsequent step of resin synthesis.

[0086] The step of separating the pyrolysis oil into at least one raffinate, an intermediate fraction and an extract can be carried out by any means known to those skilled in the art making it possible to increase the concentration of C Cia olefinic monomers and to limit the heteroatom content.

[0087] In particular and preferably, separation step b2) is carried out by distillation, which can be carried out sequentially (batch) or continuously, in one or more intermediate steps. Thus, in a preferred arrangement, separation step b2) is carried out by distillation, the intermediate fraction being obtained by topping followed by tailing.

[0088] Topping means the removal of a light fraction, the cutting point of which is less than 140°C, preferably less than 150°C at atmospheric pressure. Tailing means the removal of a heavy fraction, the cutting point of which is greater than 280°C, preferably greater than 260°C.

[0089] In another preferred arrangement, the separation step b2) is carried out in a single distillation step, the intermediate fraction being obtained by side withdrawal from said distillation step. A particularly preferred example of implementation of this arrangement is an implementation in a so-called "internal wall" column.

[0090] In the preferred case where separation step b2) is carried out by distillation, this is preferably carried out at a pressure less than or equal to atmospheric pressure, preferably less than or equal to 0.5 bar, preferably less than or equal to 0.250 bar.

[0091] Preferably, the intermediate fraction from step c2) undergoes a purification treatment before feeding step d).

[0092] This purification treatment makes it possible, where appropriate, in particular to lower the content of compounds such as sulfur or carbonyl compounds before the intermediate fraction feeds a step d) of resin synthesis.

[0093] Preferably, the purification treatment is carried out by passing the intermediate fraction through a fixed bed of silica, alumina, activated carbon, ion exchange resins or a mixture of these constituents.

[0094] In the arrangement in which the purification treatment is carried out, the heteroatom content in the intermediate fraction at the end of the purification treatment is less than 2% by weight, preferably less than 1% by weight, preferably less than 0.9% by weight and preferably less than 0.8% by weight. Preferably, the intermediate fraction from step c2) undergoes a purification treatment by passing over a bed of alumina beads, this treatment making it possible in particular to eliminate polar impurities. The raffinate, rich in polyaromatics, can be used for the production of carbon black, for example via so-called “Blast Furnace” processes, the properties and specifications of which are comparable to those of carbon black produced from traditional raw materials.It can be used for manufacturing new rubber products, such as tires, conveyor belts or any rubber article.

[0095] The extract, low in compounds of interest for the resin synthesis step of the process according to the invention, can preferably be used as a solvent, fuel, plasticizer or be treated in refining processes in order to recover light aromatic hydrocarbons (benzene, toluene, xylenes).

[0096] Step d) of resin synthesis

[0097] The process according to the invention comprises a resin synthesis step comprising a polymerization section supplied at least by a flow from step cl) and by the intermediate fraction from step c2), followed by a finishing section and producing a polymerized effluent.

[0098] The resin synthesis step mainly consists of oligomerizing the monomers included in the stream from step c1), in particular styrene and alpha-methylstyrene, and the intermediate fraction from step c2), and thus preparing new oligomeric materials of the resin type, by controlling the macrostructure, in particular by limiting the content of low molecular weight compounds, such as monomers, dimers and trimers, and high molecular weight compounds, i.e. those with a molecular weight greater than 5000 g / mol, as well as the microstructure. A dimer is understood to mean a compound comprising two monomers linked by a covalent bond. A dimer may be a homodimer, i.e. the combination of two identical monomers, a heterodimer, i.e. the combination of two different monomers, or a mixture of homodimer and heterodimer. A trimer is a compound comprising three monomers linked by a covalent bond.A trimer can be a homotrimer, that is, the combination of three identical monomers, a heterotrimer, that is, the combination of at least two different monomers, or a mixture of homotrimer and heterotrimer.

[0099] By feeding the resin synthesis step with at least one stream from step cl) and the intermediate fraction from step c2), it is possible to control the ratio of aromatic and aliphatic units in the resin produced and thus adapt the resin to the polymer matrix in which this resin is intended to be incorporated. It is thus possible to obtain a resin with excellent compatibility from recycled resources.

[0100] Thus, the method according to the invention makes it possible to use the stream rich in light compounds, the stream rich in aromatic compounds, or the stream rich in heavy compounds depending on the parameters sought for the resin produced, which allows great versatility. Preferably, when the streams rich in light compounds, rich in heavy compounds or rich in aromatic compounds are produced by distillation in step c1), no other treatment is required before using one of these streams for the production of resin.

[0101] Preferably, the mass ratio of flow from step cl) to the intermediate fraction from step c2) feeding step d) is adjusted so that the resin obtained has a molar ratio of aliphatic H to aromatic H ranging from 40 / 60 to 95 / 5, preferably ranging from 50 / 50 to 90 / 10, preferably ranging from 55 / 45 to 90 / 10.

[0102] Preferably, the polymerization section is also supplied with a stream of solvent chosen from aliphatic, aromatic, halogenated solvents and their mixtures.

[0103] Preferably, the solvent chosen from aliphatic, aromatic, halogenated solvents and their mixtures is chosen from C7 aromatic solvents. _ C10, C6 aliphatic solvents _ C8 and C1 chlorinated solvents _ C2 and their mixtures, preferably among toluene, methylcyclohexane and dichloromethane.

[0104] Preferably, a fraction of the pyrolysis oil from step b1) is used as solvent stream. Preferably, the process according to the invention is fed only with the feedstock of styrenic compounds and the intermediate fraction from step c2), the solvent required in step d) being provided by at least one stream from step c1) and / or at least one fraction of the pyrolysis oil from step b), preferably only at least one fraction of the pyrolysis oil from step b) feeding step d).

[0105] Preferably, synthesis step d) is fed with a flow from step b), with an intermediate fraction from step c2) and with a solvent flow such that the monomer content is between 50 and 75% by weight. Thus, the solvent flow rate can be adapted so as to adjust the monomer content in step d). This content makes it possible to limit the exothermicity within step d), while making it possible to obtain a polymerized effluent whose viscosity allows conveyance to the downstream steps of the process of the invention. Preferably, the resin obtained by the process according to the invention comprises less than 1% by weight of compounds whose molecular mass is greater than 5000 g / mol. Preferably, the resin obtained comprises at most 50% by weight of dimeric and trimer compounds.

[0106] The polymerization section is operated in the absence of a catalyst, or in the presence of an acid catalyst, such as a Bronsted acid, Lewis acid or Friedel-Crafts acid, said catalyst being able to be homogeneous or heterogeneous. Preferably, said polymerization section is operated in the presence of an acid catalyst, such as a Bronsted acid or Lewis acid. Said polymerization section can also be operated in the presence of ligands, a cocatalyst, and / or a cationic polymerization initiator, for example of the proton or carbocation generator type.

[0107] Preferably, the catalyst is a Lewis acid comprising ligands from the aluminum halide family. Preferably, these ligands are chosen from aluminum chlorides, for example aluminum trichloride, alkylaluminum chlorides, such as diethylaluminum chloride and ethylaluminum dichloride, and arylaluminum chlorides, such as phenylaluminum chloride. Preferably, the catalyst also comprises a co-ligand with Lewis base character, making it possible to modulate the acid character of the Lewis acid ligand, of the aliphatic ether type (for example diethyl ether, dibutyl ether), aromatic ether (diphenyl ether), or ester (ethyl acetate) or alkyl amines (triethylamine) or arylamines (diphenylamine, triphenylamine). The polymerization section can also be operated with ligands containing phosphorus, sulfur or any other heteroatom.

[0108] The polymerization section is preferably operated at a temperature ranging from -60°C to +300°C, preferably ranging from -60°C to +120°C, very preferably ranging from -50°C to +100°C and preferably ranging from -40°C to +90°C and very preferably ranging from +20 to +90°C.

[0109] The average residence time in the polymerization section is preferably between 0.25 h and 7 h, preferably between 0.5 h and 4 h. When the polymerization section is operated continuously, the average residence time in said section is the ratio of the reaction volume of said section to the volume flow rate of the feeds of the section.

[0110] The quantity of catalyst, including possible ligands and co-ligands, is preferably in a range from 0.05% to 5% by weight relative to the weight of olefinic monomers entering the polymerization section, and preferably ranges from 0.1% to 2% by weight relative to the weight of olefinic monomers (styrene, alpha _ methylstyrene, limonene, indene) at the entrance to the polymerization section.

[0111] The stream from the polymerization section is then treated in a finishing section producing a polymerized effluent.

[0112] This finishing section makes it possible to stop the polymerization reaction by the addition of a compound which deactivates the catalyst and stops the chains still growing. The finishing section is preferably implemented by contacting with a flow comprising a stopper compound chosen from water, a CLC3 alcohol and their mixtures, preferably chosen from water, methanol, ethanol and their mixture, very preferably water at a temperature between 5 and 80°C, preferably at a temperature between 15 and 30°C (for example at room temperature), followed by separation by phase decantation of a polymerized effluent and an effluent mainly comprising the stopper compound.

[0113] The molar ratio of stopper compound to polymerization catalyst in the finishing section is at least 1.1, preferably at least 2.

[0114] When the stopper compound is water, the volume ratio of reaction medium to water in the finishing section is preferably between 20 : l and 10 : l, preferably between 10 : l and 5 : 1 and preferably between 5 : 1 and LL

[0115] The flow from the polymerization section and the flow comprising the stopper compound are brought into contact with stirring for a period preferably ranging from 5 min to 2 h, preferably ranging from 15 min to 45 min, in order to promote contact between the stopper compound and the reaction medium.

[0116] At the end of this agitation phase, a decantation phase is carried out in order to separate on the one hand an organic phase constituting the polymerized effluent containing mainly the resins, the solvent, the unconverted monomers, dimers, trimers and oligomers of low molecular weight and a phase containing mainly the stopper compound, the catalytic residues and organic residues soluble in the stopper compound.

[0117] The decantation phase is preferably carried out for a period ranging from 5 min to 4 h, preferably from 15 min to 2 h. The phase mainly containing the stopper compound can then be treated in order to recycle the stopper compound in the finishing section.

[0118] The polymerized effluent then feeds the treatment stage.

[0119] Step e) treatment of the polymerized effluent

[0120] The method according to the invention comprises a step of treating the polymerized effluent from step d) comprising a section for separating a solvent-rich effluent and a resin-rich effluent, and a drying section supplied with the resin-rich effluent in order to produce the resins.

[0121] The implementation of the polymerized effluent treatment step in the process according to the invention makes it possible to adjust the characteristics of the resins, in particular by eliminating low molecular mass oligomers (dimers, trimers, tetramers for example) and by reducing the dispersity, in order to control the properties of the resins obtained (glass transition temperature for example).

[0122] The separation section of a solvent-rich effluent and a resin-rich effluent makes it possible, on the one hand, to recover a majority of the solvent and unconverted monomers for subsequent use, preferably for recycling them in the resin synthesis stage of the process according to the invention, and on the other hand to concentrate the resins in the resin-rich effluent.

[0123] The separation section can be carried out by any method known to those skilled in the art, in particular and preferably by evaporation, distillation, coagulation of resins, liquid-liquid extraction or a combination of these methods.

[0124] In a preferred arrangement, the separation section is carried out by distillation in at least one distillation column so as to produce a solvent-rich effluent at the top and a resin-rich effluent at the bottom. This section makes it possible to eliminate the residual monomers and oligomers at the top as well as the majority of the solvent used in the resin synthesis step and thus to adjust the macrostructure of the resins as well as its properties, for example the glass transition temperature noted Tg, in particular by reducing the dispersity by eliminating the low molecular weight compounds. The resin-rich effluent comprises the majority of the resins feeding the separation section. The resin recovery rate, corresponding to the ratio of the resin flow rate in the resin-rich effluent to the resin flow rate in the feed of the separation section, is preferably greater than 80%, more preferably greater than 90%.This recovery rate can be adjusted by increasing the number of separation stages in the separation section, or by adjusting the operating parameters of said section, for example the reflux rate.

[0125] In another preferred arrangement, the separation section is carried out by coagulation of the resins. In this arrangement, the polymerized effluent from step d) is brought into contact with a coagulation solvent in which the resins are not soluble in order to precipitate them. The coagulation solvent solubilizes the residual monomers, the solvent used in the resin synthesis step and the low molecular weight oligomers.

[0126] The coagulation solvent is preferably chosen from polar protic or aprotic solvents with a low boiling point such as alcohols, for example methanol, ethanol and isopropanol, acetone, ethers, for example tetrahydrofuran (denoted THF) and dioxane.

[0127] The coagulation separation section is preferably operated with a coagulation solvent / medium to be coagulated volume ratio ranging from 14 to 104, preferably ranging from 24 to 54. The coagulation separation section is preferably operated at a temperature ranging from 5°C to 40°C.

[0128] The stream comprising the coagulation solvent, constituting the solvent-rich effluent, can then be recycled, for example to the resin synthesis stage, undergoing a purification treatment stage beforehand, if necessary.

[0129] In another preferred arrangement, the separation section is carried out by liquid-liquid extraction. In this arrangement, the polymerized effluent from step d) is washed with a stream comprising mainly water. This extraction can be carried out in one or more stages, preferably in one to three stages.

[0130] Liquid-liquid extraction can also be implemented upstream of a separation by distillation or by coagulation of the resins as described previously.

[0131] In another preferred arrangement, the separation section is carried out by evaporation, for example by evaporation in a wiped film evaporator. The viscosity of the resin-rich effluent depends on the resin content in this effluent and its temperature. These contents and temperatures are therefore adjusted so that this effluent can be transported to the drying section. One may seek to maintain a high temperature to have a high resin content while maintaining a viscosity of the effluent allowing its transport, taking care to remain below the temperatures at which the resins degrade thermally.

[0132] The resin-rich effluent then feeds a drying section in which it is filtered and then dried. At the end of the drying step, the dried resins have a residual solvent content (grouping together the solvent(s) used in the synthesis step as well as the solvent(s) possibly used in the separation section) of less than 3% by weight, preferably less than 1.5% by weight and preferably less than 0.8% by weight relative to the mass of resins. The dried resins have a residual free monomer content of less than 5% by weight, preferably less than 2% by weight and preferably less than 1% by weight relative to the mass of resins.

[0133] Measurement methods

[0134] Glass transition temperature

[0135] The glass transition temperature Tg is measured in a known manner by differential scanning calorimetry, or DSC (Differential Scanning Calorimetry), for example and unless otherwise specified, according to ISO 11357'2 of 2014.

[0136] Macrostructure (Mw, Mn, Mz and D)

[0137] The macrostructure (mass-average, number-average, centrifugation average molar mass and polydispersity index, respectively denoted Mw, Mn, Mz and D) is determined by size exclusion chromatography (SEC) as shown below. Mz reflects the thermodynamic equilibrium between sedimentation and diffusion and depends on its size. This higher-order average is used as an indication of the proportion of high molar masses present in the sample.

[0138] As a reminder, SEC analysis, for example, consists of separating macromolecules in solution according to their size through columns filled with a porous gel; the molecules are separated according to their hydrodynamic volume, the largest being eluted first.

[0139] The sample to be analyzed is simply previously solubilized in a suitable solvent, tetrahydrofuran at a concentration of 1.5 g / liter. Then the solution is filtered through a 0.45 μm porosity filter, before injection into the apparatus at a flow rate of 1 ml / min and a temperature of 35°C. The apparatus used is, for example, a "Waters Alliance" chromatographic chain.

[0140] A Moore calibration is carried out with a series of commercial standards of low-D polystyrene (less than 1.2), of known molar masses, covering the mass range to be analyzed. From the recorded data (molar mass distribution curve) Mw, Mn, as well as D = Mw / Mn, are deduced.

[0141] All molar mass values ​​indicated in this application are therefore relative to calibration curves produced with polystyrene standards.

[0142] The molar distribution of aliphatic, ethylenic and aromatic protons is measured using a spectrometer, here a Brucker AVANCE III 400 MHz spectrometer and is expressed as raw peak area ratios. The solvent used is CDC13 (deuterated chloroform) at 25°C and 120 scans.

[0143] Hydrocarbon resin NMR data are measured by dissolving 20 ± 1 mg of sample in 0.7 ml of solvents. Samples are dissolved in a 5 mm NMR tube at 25 °C until the sample is dissolved. CDCl3 appears as a peak at 7.20 ppm and is used as a reference peak for the samples. 1H NMR signals of aromatic protons are located between 8.5 ppm and 6.2 ppm. Ethylene protons lead to signals between 6.2 ppm and 4.5 ppm. Finally, signals corresponding to aliphatic protons are located between 4.5 ppm and Oppm. Signals corresponding to solvent, water and other possible impurities are subtracted when integrating the resin signals.

[0144] The areas of each category of protons are reported to the sum of these areas to give a distribution in % of area of ​​each category of protons.

[0145] Description of figures

[0146] [Fig 1] Figure 1 represents a schematic view of the method according to the invention.

[0147] A charge of styrenic compounds (1) feeds a step a) of preparing the charge of styrenic compounds so as to be able to feed (2) this charge in the step b1) of pyrolysis. The step b1) of pyrolysis of the charge of styrenic compounds makes it possible to obtain at least one gaseous effluent (3) and one pyrolysis oil (4), said gaseous effluent (3) comprising at least 20% by weight of aromatic compounds.

[0148] The gaseous effluent (3) is then treated in a separation step cl) in which it is separated into at least one stream rich in light compounds (7), one stream rich in aromatics (6) and one stream rich in heavy compounds (5).

[0149] A feedstock comprising rubber chips (8) feeds a pyrolysis step b2). Step b2) of pyrolysis of the feedstock comprising rubber chips makes it possible to obtain at least one gaseous effluent (11), one pyrolysis oil (9) and one solid effluent (10).

[0150] Said pyrolysis oil (9) is then treated in a separation step c2) in which it is separated into at least one extract (14), an intermediate fraction (13) and a raffinate (12).

[0151] At least one of the streams (5), (6) or (7) and the intermediate fraction (13) feed a step d) of resin synthesis comprising a polymerization section fed by these streams, and optionally by a solvent stream (15), the polymerization section being followed by a finishing section producing a polymerized effluent (16).

[0152] The polymerized effluent (16) feeds a treatment step e) comprising a section for separating the polymerized effluent (16) from step d) into a solvent-rich effluent (18) and a resin-rich effluent, and a drying section fed by the resin-rich effluent in order to produce a stream of hydrocarbon resins (17).

[0153] Example of a method according to the invention

[0154] This example illustrates the production of hydrocarbon resins from a styrenic feedstock and a feedstock comprising rubber chips.

[0155] A charge of styrenic compounds (1), here polystyrene, feeds a preparation step a), here an extruder, in which it is heated to a temperature of 250°C. The liquid part of the charge (2) feeds a pyrolysis step b1), here a microwave pyrolysis, carried out at a temperature of 340°C and at a pressure of 1.1 bar. The gaseous effluent (3) from the pyrolysis step is separated by distillation in a separation step c1) into a stream rich in light compounds (4), a stream rich in aromatics (5) comprising 99.2% by weight of styrene and a stream rich in heavy compounds (5). The stream rich in heavy compounds (5) has the following composition: ■ 77.6% by weight of alpha-methylstyrene, 17.6% by weight of Styrene, 1.7% by weight of cumene and 1.2% by weight of ethylbenzene.

[0156] A charge comprising rubber chips (8), here chips from tire treads having an average diameter of less than approximately 1 mm and having an isoprene elastomer content of 60% by weight, feeds a pyrolysis step b2). This step is carried out under an inert nitrogen atmosphere with a flow rate of 2 liters per minute, in a microwave batch reactor, subjected to a power of 300W for 160 min.

[0157] At the reactor outlet, a gaseous effluent (11), a liquid pyrolysis oil (9) and a solid effluent (10) are separated with the following respective yields (effluent flow rate / feed flow rate): ■ 18.2%, 37.8% and 43.9%. The pyrolysis oil (9) comprises approximately 5% by weight of several monomers of interest, including styrene, methylstyrene, indene and limonene.

[0158] The pyrolysis oil (9) feeds a separation step c2) by distillation carried out in two sections at atmospheric pressure. In a first section, a light fraction, whose initial boiling point is less than 160°C, constituting the extract (14), is separated. The heavier fraction feeds a second section making it possible to produce a raffinate (12) whose cutting point is 280°C, i.e. whose initial boiling point is 280°C at atmospheric pressure, and an intermediate fraction constituting the intermediate fraction (13). The olefinic monomer content in this fraction is approximately 48% by weight, including 42.7% by weight of limonene, 2.0% by weight of styrene and 3.8% by weight of indene.

[0159] The intermediate fraction (13) is passed over a bed of alumina balls in order to remove polar impurities.

[0160] The intermediate fraction (13) of composition 42.7% by weight of limonene, 2.0% by weight of styrene and 3.8% by weight of indene feeds, with the stream rich in heavy compounds (5) of composition 77.6% by weight of alpha-methylstyrene, 17.6% by weight of styrene, 1.7% by weight of cumene and 1.2% by weight of ethylbenzene, a resin synthesis step d). This step is also fed by a solvent stream (15), here toluene, the flow rate of which is adjusted so that the sum of the contents of limonene, styrene, indene, methylstyrene and beta-pinene monomers is 30% by weight in the mixture of the stream rich in heavy compounds (5), the intermediate fraction (13) and the solvent stream (15). The mass ratio of the intermediate fraction flow (13) to the flow rich in heavy compounds (5) is equal to 0.1, i.e. 10% by mass of intermediate flow (13) and 90% by mass of flow rich in heavy compounds (5).Aluminum chloride (2mol% relative to the content of limonene, styrene, indene, methylstyrene and beta monomers. _ pinene) is introduced into a reactor under an inert atmosphere. The reactor is then kept under an inert atmosphere throughout the reaction.

[0161] The medium is stirred and operated at a temperature of 50°C for 2 hours. The reaction is then stopped by adding water.

[0162] The reaction medium, constituting the polymerized effluent (16), is separated into a solvent-rich effluent (18) and a resin-rich effluent by washing with water and coagulation of the resins with methanol. The resin-rich effluent is then dried in an oven at 180°C for 16 h. A resin (17) is recovered in the form of an orange translucent solid.

[0163] This Cl resin has the following characteristics ■ [Table 1]

Claims

CLAIMS

1. A process for producing hydrocarbon resins from a feedstock of styrenic compounds and a feedstock comprising rubber chips, said process comprising at least ■ a. A step of preparing the feedstock of styrenic compounds so as to be able to feed this feedstock into the pyrolysis step; bl. A step of microwave pyrolysis of the feedstock of styrenic compounds making it possible to obtain at least one gaseous effluent and one pyrolysis oil, said gaseous effluent comprising at least 20% by weight of aromatic compounds; cl. A step of separating the gaseous effluent from step bl) into at least one stream rich in light compounds, one stream rich in aromatics and one stream rich in heavy compounds b2.A step of microwave pyrolysis of the feedstock comprising rubber chips carried out at a temperature between 300 and 900°C, making it possible to obtain a gaseous effluent, a pyrolysis oil and a solid effluent, said pyrolysis oil comprising at least 1.5% by weight of C Cia J c2 olefinic monomers. A step of separation of the pyrolysis oil resulting from step b2) into at least one raffinate, an intermediate fraction and an extract, the intermediate fraction having a boiling point at atmospheric pressure, measured according to standard ASTM D86-23, between 140 and 280°C and comprising at most 10% by weight of heteroatoms d. A step of synthesis of resins comprising a polymerization section supplied at least by a flow resulting from step c1) and by the intermediate fraction resulting from step c2), followed by a finishing section and producing a polymerized effluent e.A treatment step comprising a section for separating the polymerized effluent from step d) into a solvent-rich effluent and a resin-rich effluent, and a drying section fed with the resin-rich effluent in order to produce a stream of hydrocarbon resins.

2. Method according to the preceding claim in which the charge of styrenic compounds is a charge of styrenic compounds from plastic waste comprising at least 90% by weight of polystyrene.

3. Method according to the preceding claim in which the rubber chips comprise at least 50 pce of diene elastomer, preferably at least 60 pce of diene elastomer.

4. Process according to any one of the preceding claims in which the charge of styrenic compounds is gradually heated during step a) to a temperature between 100°C and 300°C, preferably between 150°C and 300°C and more preferably between 200°C and 300°C.

5. Process according to any one of the preceding claims in which the pyrolysis step b1) comprises a pyrolysis reactor operated at a temperature ranging from 300°C to 900°C and preferably ranging from 300 to 800°C and a pressure ranging from 0.8 bar to 7.5 bar.

6. A process according to any one of the preceding claims wherein the separation step cl) is carried out by distillation.

7. Process according to any one of the preceding claims in which the mass ratio of flow from step cl) to the intermediate fraction from step c2) feeding step d) is adjusted so that the resin obtained has a molar ratio of aliphatic H to aromatic H ranging from 40 / 60 to 95 / 5, preferably ranging from 50 / 50 to 90 / 10, more preferably ranging from 55 / 45 to 90 / 10.

8. Process according to any one of the preceding claims in which the polymerization section of step d) of resin synthesis is also supplied with a stream of solvent chosen from aliphatic, aromatic, halogenated solvents and their mixtures.

9. Process according to any one of claims 1 to 8 supplied solely by the feedstock of styrenic compounds and the feedstock comprising rubber chips, the solvent required in step d) being provided by at least one stream from step c2) and / or at least a fraction of the pyrolysis oil from step bl).

10. Process according to the preceding claim in which at least a fraction of the pyrolysis oil from step b1) feeds step d) of resin synthesis.

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