Process for the production of hydrocarbon resins from polystyrene residudes

Abstract

The invention relates to a process for producing hydrocarbon resins from a feedstock of styrene compounds and a stream of aliphatic compounds comprising at least 5% by weight of bio-based terpene compounds.

Description

[0001] Process for producing hydrocarbon resins from polystyrene residues

[0002] Technical field of the invention

[0003] The present invention relates to the field of processes for producing hydrocarbon resins, in particular for rubber articles and in particular vehicle tires, from recycled residues.

[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] A hydrocarbon resin is a resin consisting of carbon and hydrogen. 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 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 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-based streams. If the performance of tires such as rolling resistance and wear resistance are key to limiting their environmental impact, 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, 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; b. A step of 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 c. A step of separating the gaseous effluent into at least one stream rich in light compounds, one stream rich in aromatic compounds and one stream rich in heavy compounds d. A step of synthesizing resins comprising a polymerization section fed at least by a stream from step c) and by a stream of aliphatic compounds comprising at least 5% by weight of terpenic compounds of biosourced origin, followed by a finishing section and producing a polymerized effluent e.A treatment step comprising a section for separating the polymerized effluent from step c) 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. Preferably, the feedstock of styrenic compounds is a feedstock of styrenic compounds from plastic waste comprising at least 90% by weight of polystyrene.

[0012] Preferably, the terpene compounds are chosen from terpenes comprising at most 20 carbon atoms, preferably chosen from the compounds limonene, alpha-pinene, beta-pinene, myrcene, farnesene and their mixtures, preferably chosen from the compounds limonene, alpha-pinene, beta-pinene and their mixtures and preferably are limonene.

[0013] 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.

[0014] Preferably, the pyrolysis step 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.

[0015] Preferably, the pyrolysis step implements a microwave pyrolysis step.

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

[0017] Preferably, in step c), a first column fed with the gaseous effluent from step b) 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 aromatic compounds and a stream rich in heavy compounds.

[0018] Preferably, step c) is carried out in a single distillation column operated at a pressure of between 0.1 and 2.0 bar, preferably between 0.5 and 1.5 bar and preferably between 0.5 and 1.1 bar, the distillation column being fed at the bottom of the column with at least the gaseous effluent from step b) and producing 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 aromatic compounds, said column having as its sole heat supply said gaseous effluent from step b).

[0019] Preferably, the mass ratio of flow from step b) to the flow of aliphatic compounds 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.

[0020] 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.

[0021] In a preferred arrangement, the process according to the invention is fed solely by the feedstock of styrenic compounds and the stream of aliphatic compounds comprising at least 5% by weight of terpenic compounds of biosourced origin, the solvent required in step d) being provided by at least one stream from step c) and / or at least a fraction of the pyrolysis oil from step b).

[0022] Preferably, in this arrangement, at least a fraction of the pyrolysis oil from step b) feeds step d) of resin synthesis.

[0023] Preferably, the polymerization section is operated at a temperature ranging from +20 to +90°C, with a residence time of between 0.5 h and 4 h, in the presence of 0.1% to 2% by weight of catalyst relative to the weight of monomers at the inlet of the polymerization section and a mass ratio of flow from step b) to the flow of terpene compounds of biosourced origin such that the rate of aromatic protons, determined by 1H NMR, is between 0.5% mol and 99% mol, preferably between 1% mol and 50% mol, preferably between 2% mol and 40% mol, preferably between 2% mol and 30% mol and the rate of aliphatic protons, determined by 1H NMR, is between 99.5% mol and 1% mol, preferably between 99% mol and 50% mol, preferably between 98%mol and 70%mol.

[0024] The invention also relates to a hydrocarbon resin obtained from the process according to the invention according to any one of its preferred arrangements or variants, said resin having the following characteristics: ■ a glass transition temperature (denoted Tg) ranging from 20°C to 140°C; a number-average molar mass of less than 5000 g / mol, preferably less than 4000 g / mol and preferably less than 3000 g / mol; a dispersity D of less than 3, preferably less than 2.5 and preferably less than 2;

[0025] An aromatic proton level, determined by 1H NMR, of between 0.5 mol% and 99 mol%, preferably between 1 mol% and 50 mol%, preferably between 2 mol% and 40 mol%, preferably between 2 mol% and 30 mol% and preferably between 2 mol% and 20 mol%;

[0026] A rate of aliphatic protons, determined by 1H NMR, between 1% mol and 99.5% mol, preferably between 50% mol and 99% mol, preferably between 70% mol and 98% mol

[0027] A rate of ethylenic protons, determined by 1H NMR, less than or equal to 10% mol, preferably less than or equal to 5% mol, preferably less than or equal to 4% mol, the sum of the rates of aromatic, aliphatic and ethylenic protons being equal to 100%.

[0028] Definitions

[0029] 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.

[0030] 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.

[0031] A heteroatom is an atom other than carbon or hydrogen, for example nitrogen, sulfur, oxygen.

[0032] Process load

[0033] The process according to the invention is a process for producing hydrocarbon resins from a feedstock of styrenic compounds and an aliphatic stream of biosourced origin. By feedstock of styrenic compounds is meant a feedstock which comprises styrene-based polymers, such as styrenic rubbers and polystyrene.

[0034] Preferably, the feedstock of styrenic compounds is a feedstock of styrenic compounds derived from plastic waste. Such a feedstock 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 feedstock 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. The process according to the invention is also fed with a flow of aliphatic compounds, comprising at least 5% by weight of terpene compounds, of biosourced origin.

[0035] The stream of aliphatic compounds is of bio-sourced origin. That is, it comes from biomass or is derived from biomass products.

[0036] By derived from biomass, it is meant that the compounds are derived, after possible treatment, from plant, animal, fungal or microbe organisms. Preferably, the stream of aliphatic compounds is derived from plant organisms. By derived from products derived from biomass, it is meant that the biomass used to obtain the stream of aliphatic compounds may have undergone a treatment such as a biological treatment, based for example on the functioning of plants, animals, or microorganisms, a chemical treatment, such as for example a treatment in the presence of acid, an alkali treatment, in the presence or absence of a catalyst, and / or a physical treatment such as pressurization, a heat treatment, an electromagnetic treatment or a microwave treatment.

[0037] Step a) preparation

[0038] 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.

[0039] 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.

[0040] Step b) of pyrolysis

[0041] 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.

[0042] Pyrolysis means the thermal decomposition of compounds in an inert atmosphere. The feedstock is fed into a pyrolysis step, which is 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, more preferably from 300°C to 800°C.

[0043] 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.

[0044] Preferably, the pyrolysis step 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.

[0045] 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 reaction mass temperature than a conventional pyrolysis section. The lower reaction mass temperatures result in lower styrene oligomer evaporation rates and help prevent over-cracking of the styrene product. Using a microwave pyrolysis step will reduce the formation of styrene oligomers compared to a conventional pyrolysis step, as well as reactor fouling.

[0046] 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.

[0047] The gaseous effluent comprises at least 20% by weight of aromatic compounds, preferably at least 20% by weight of styrene.

[0048] 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. Preferably, the gaseous effluent comprises at least 10% by weight of compounds whose boiling point is higher than that of styrene.

[0049] 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 of the pyrolysis step or used in step d) of resin synthesis.

[0050] 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.

[0051] Step c) separation

[0052] The process according to the invention comprises a separation step supplied at least with the gaseous effluent from step b) and producing at least one stream rich in light compounds, one stream rich in aromatic compounds and one stream rich in heavy compounds.

[0053] The light-rich stream consists mainly of compounds lighter than styrene, particularly toluene and ethylbenzene compounds.

[0054] The stream rich in light compounds is a T100°C-140°C cut, preferably a T110°C-140°C cut. By "Ta°Cb°C Cut" is meant that the bubble point and the dew point of the cut, measured at atmospheric pressure, are included in the temperature range from a°C to b°C. The stream rich in light compounds therefore has a bubble point and a dew point measured at atmospheric pressure in the temperature range from 100 to 140°C, preferably from 110 to 140°C.

[0055] Preferably, the cumulative content of toluene and ethylbenzene in the stream rich in light compounds is at least equal to 60% by mass, preferably is at least equal to 70% by mass, and preferably is at least equal to 75% by mass.

[0056] The stream rich in aromatic compounds mainly comprises aromatic compounds comprising from 6 to 9 carbon atoms. The separation step c) is carried out so that the stream rich in aromatic compounds comprises at least 99% by mass of styrene and the styrene recovery rate, i.e. the ratio of the styrene flow rate in the stream rich in aromatic compounds to the styrene flow rate in the gaseous effluent from step b) is at least equal to 90%, preferably at least equal to 95% and more preferably at least equal to 97%.

[0057] Preferably, the stream rich in aromatic compounds is a T140°C-150°C cut, preferably a T144°C-146°C cut.

[0058] The stream rich in heavy compounds mainly comprises compounds heavier than styrene, as well as non-depolymerized styrenic compounds, and in particular styrene oligomers when the feed includes polystyrene.

[0059] The flow rich in heavy compounds is a T150°C-220°C cut, preferably a T160°C-210°C cut.

[0060] Preferably, the alpha-methylstyrene content in the stream rich in heavy compounds is at least equal to 60% by mass, preferably is at least equal to 70% by mass, preferably is at least equal to 80% by mass and very preferably is at least equal to 90% by mass.

[0061] Preferably, separation step c) is carried out by distillation.

[0062] In a first variant of this preferred arrangement, a first column fed with the gaseous effluent from step b) 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 aromatic compounds and a stream rich in heavy compounds.

[0063] 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.

[0064] 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".

[0065] In this variant and preferably, the distillation column is fed at the bottom of the column with at least the gaseous effluent from step b) 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 aromatic compounds, said column having as its only heat input said gaseous effluent from step b).

[0066] The gaseous effluent from step b) is at a high temperature, preferably at a temperature above 300°C. This temperature is sufficient so that the column does not require any further heat input.

[0067] 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 distillation column at the correct temperature, greatly limits the risk of fouling by so-called heavy compounds, which are particularly viscous.

[0068] The distillation column implemented in this variant of step c) of the process according to the invention comprises from 5 to 20 theoretical stages, preferably at most 15 theoretical stages, preferably from 8 to 12 theoretical stages.

[0069] A stream rich in aromatic compounds 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, makes it possible to limit the entrainment of heavy compounds in the stream rich in aromatic compounds and thus limits the risks of fouling subsequent equipment. 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.

[0070] 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.

[0071] Step d) of resin synthesis

[0072] The process according to the invention comprises a resin synthesis step comprising a polymerization section supplied at least by a flow from step c) and by a flow of aliphatic compounds comprising at least 5% by weight of terpene compounds of biosourced origin, followed by a finishing section and producing a polymerized effluent.

[0073] The resin synthesis step mainly consists of oligomerizing the monomers included in the stream from step b), in particular styrene and alpha-methylstyrene, and the stream of aliphatic compounds comprising at least 5% by weight of terpene compounds of biosourced origin, and thus of 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. whose molecular weight is greater than 5000 g / mol, as well as the microstructure. By dimer is meant a compound comprising two monomers linked by a covalent bond. A dimer can be a homodimer, that is, the combination of two identical monomers, a heterodimer, that is, 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, i.e., the combination of three identical monomers, a heterotrimer, i.e., the combination of at least two different monomers, or a mixture of homotrimer and heterotrimer.

[0074] By terpene compounds of biosourced origin, we mean compounds of the terpene family which are unsaturated hydrocarbons of plant origin. The terpene compounds useful for the purposes of the invention are preferably chosen from terpenes comprising at most 20 carbon atoms, preferably chosen from the compounds limonene, alpha-pinene, beta-pinene, myrcene, farnesene and their mixtures, preferably chosen from the compounds limonene, alpha-pinene, beta-pinene and their mixtures and preferably are limonene.

[0075] Limonene is a terpene hydrocarbon that can be obtained, in particular, from citrus peels or by microbial fermentation.

[0076] By feeding the resin synthesis step with at least one stream from step b) and one stream of aliphatic compounds, the ratio of aromatic and aliphatic units in the resin produced can be controlled and thus the resin can be adapted 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 renewable and / or recycled resources.

[0077] 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 c), no other treatment is required before using one of these streams for the production of resin.

[0078] Preferably, the mass ratio of flow from step b) to the flow of aliphatic compounds 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.

[0079] Preferably, the polymerization section is also supplied with a stream of solvent chosen from aliphatic, aromatic, halogenated solvents and their mixtures.

[0080] 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.

[0081] Preferably, a fraction of the pyrolysis oil from step b) is used as solvent stream. Preferably, the process according to the invention is fed only with the feedstock of styrenic compounds and the stream of aliphatic compounds comprising at least 5% by weight of terpene compounds of biosourced origin, the solvent required in step d) being provided by at least one stream from step c) and / or at least one fraction of the pyrolysis oil from step b), preferably at least one fraction of the pyrolysis oil from step b) feeding step d).

[0082] Preferably, synthesis step d) is fed with a flow from step b) and with a flow of aliphatic compounds comprising at least 5% by weight of terpene compounds and with a flow of solvent 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 it to be conveyed to the downstream steps of the process of the invention.

[0083] 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 trimeric compounds.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] The quantity of catalyst, including possible ligands and codigands, is preferably within a range from 0.05% to 5% by weight relative to the weight of olefinic monomers intended to react, in particular limonene, alpha _methylstyrene and styrene, at the inlet of the polymerization section, and preferably ranges from 0.1% to 2% by weight relative to the weight of olefinic monomers at the inlet of the polymerization section.

[0089] The stream from the polymerization section is then treated in a finishing section producing a polymerized effluent.

[0090] 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.

[0091] The molar ratio of stopper compound to polymerization catalyst in the finishing section is at least 1.1, preferably at least 2.

[0092] 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

[0093] 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.

[0094] 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.

[0095] The decantation phase is preferably carried out for a period ranging from 5 min to 4 h, preferably ranging from 15 min to 2 h.

[0096] The phase containing mainly the stopper compound can then be processed in order to recycle the stopper compound in the finishing section.

[0097] The polymerized effluent then feeds the treatment stage.

[0098] Step e) treatment of polymerized effluent

[0099] 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.

[0100] 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).

[0101] 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 step of the process according to the invention, and on the other hand to concentrate the resins in the resin-rich effluent. 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 the resins, liquid-liquid extraction or a combination of these methods.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] The stream comprising the coagulation solvent, constituting the solvent-rich effluent, can then be recycled, for example to the resin synthesis stage, by first undergoing, if necessary, a purification treatment stage. In another preferred arrangement, the separation section is carried out by liquid-liquid extraction. In this arrangement, the polymerized effluent from stage 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.

[0107] Liquid-liquid extraction can also be implemented upstream of a separation by distillation or by coagulation of the resins as described previously.

[0108] In another preferred arrangement, the separation section is carried out by evaporation, for example by evaporation in a wiped film evaporator.

[0109] The viscosity of the resin-rich effluent depends on the resin content in the effluent and its temperature. These contents and temperatures are therefore adjusted so that the effluent can be transported to the drying section. One can seek to maintain a high temperature to achieve a high resin content while maintaining an effluent viscosity that allows its transport, while ensuring that it remains below the temperatures at which the resins thermally degrade.

[0110] 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 more preferably less than 0.8% by weight relative to the mass of resins. The dried resins have a residual content of free monomers of less than 5% by weight, preferably less than 2% by weight and more preferably less than 1% by weight relative to the mass of resins.

[0111] In the process according to the invention, the polymerization section is preferably operated at a temperature ranging from +20 to +90°C, with a residence time of between 0.5 h and 4 h, in the presence of 0.1% to 2% by weight of catalyst relative to the weight of monomers at the inlet of the polymerization section and a mass ratio of flow from step b) to the flow of terpene compounds of biosourced origin such that the level of aromatic protons, determined by 1H NMR, is between 0.5% mol and 99% mol, preferably between 1% mol and 50% mol, preferably between 2% mol and 40% mol, preferably between 2% mol and 30% mol and the level of aliphatic protons, determined by 1H NMR, is between 99.5% mol and 1% mol, preferably between 99% mol and 50% mol, preferably between 98% mol and 70% mol

[0112] Resin

[0113] The present invention also relates to a hydrocarbon resin obtained from the process described herein, said resin having the following characteristics ■

[0114] • a glass transition temperature (noted Tg) ranging from 20°C to 140°C

[0115] • a number-average molar mass of less than 5000 g / mol, preferably less than 4000 g / mol and more preferably less than 3000 g / mol

[0116] • a dispersity D of less than 3, preferably less than 2.5 and more preferably less than 2;

[0117] • A rate of aromatic protons, determined by 1H NMR, between 0.5% mol and 99% mol, preferably between 1% mol and 50% mol, preferably between 2% mol and 40% mol, preferably between 2% mol and 30% mol and preferably between 2% mol and 20% mol

[0118] • A level of aliphatic protons, determined by 1H NMR, between 1% mol and 99.5% mol, preferably between 50% mol and 99% mol, preferably between 70% mol and 98% mol

[0119] • A level of ethylenic protons, determined by 1H NMR, less than or equal to 10% mol, preferably less than or equal to 5% mol, preferably less than or equal to 4% mol, the sum of the levels of aromatic, aliphatic and ethylenic protons being equal to 100%.

[0120] Measurement methods

[0121] Glass transition temperature

[0122] 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.

[0123] Macrostructure (Mw, Mn, Mz and D)

[0124] The macrostructure (mass-average molar mass, number-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. 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, with the largest being eluted first.

[0125] The sample to be analyzed is simply previously solubilized in a suitable solvent, tetrahydrofuran at a concentration of 1 g / liter. Then the solution is filtered through a 0.45 pm 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.

[0126] 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.

[0127] All molar mass values ​​indicated in this application are therefore relative to calibration curves produced with polystyrene standards.

[0128] 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.

[0129] 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 for 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 0 ppm. Signals corresponding to solvent, water, and other possible impurities are subtracted when integrating the resin signals.

[0130] 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.

[0131] Description of the figures [Fig 1] Figure 1 represents a schematic view of the method according to the invention.

[0132] 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 b) of pyrolysis. The step b) 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.

[0133] The gaseous effluent (3) is then treated in a separation step c) in which it is separated at least into a stream rich in light compounds (7), a stream rich in aromatic compounds (6) and a stream rich in heavy compounds (5).

[0134] At least one of these streams (5), (6) or (7) feeds a step d) of resin synthesis comprising a polymerization section also fed at least by one of these streams (5), (6) or (7) and by a stream (8) of aliphatic compounds comprising at least 5% by weight of terpene compounds of biosourced origin, and optionally by a stream of solvent (9), the polymerization section being followed by a finishing section producing a polymerized effluent (10).

[0135] The polymerized effluent (10) feeds a treatment step e) comprising a section for separating the polymerized effluent (10) from step d) into a solvent-rich effluent (12) and a resin-rich effluent, and a drying section fed by the resin-rich effluent in order to produce a stream of hydrocarbon resins (11).

[0136] Examples

[0137] 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 b), 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 c) into a stream rich in light compounds (4), a stream rich in aromatic compounds (5) comprising 99.2% by weight of styrene and a stream rich in heavy compounds (6).

[0138] The stream rich in heavy compounds (6) 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 feeds a resin synthesis step without further treatment. This step is also fed by a biosourced limonene stream comprising 99% by weight of limonene and a toluene stream, these two streams being from a source external to the process. The mass ratio of the limonene stream to the stream rich in heavy compounds is equal to 0.5. The toluene stream flow rate is such that the monomer concentration (alpha-methylstyrene + styrene + limonene) is 30% by weight at the reactor inlet.

[0139] Aluminum chloride (2 mol% relative to the content of limonene, alpha-methylstyrene and styrene monomers) is introduced into the reactor under an inert atmosphere. The reactor is then kept under an inert atmosphere throughout the reaction. The medium is stirred and operated at a temperature of 50°C for 1 h 30 min. The reaction is then stopped by adding water.

[0140] The reaction medium, constituting the polymerized effluent, is separated into a solvent-rich effluent 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 is recovered in the form of an orange translucent solid.

[0141] This resin has the following characteristics: [Table 1]

[0142] Examples lb to ld

[0143] The preparation, pyrolysis and separation steps are carried out in the same way as in Example 1.

[0144] The stream rich in heavy compounds (6) 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 feeds a resin synthesis stage without further treatment. This stage is also fed by a biosourced limonene stream comprising 99% by weight of limonene and a toluene stream. The toluene stream flow rate is such that the monomer concentration (alpha-methylstyrene + styrene + limonene) is 30% by weight at the reactor inlet.

[0145] Aluminum chloride (2 mol% relative to the content of limonene, alpha-methylstyrene and styrene monomers) is introduced into the reactor under an inert atmosphere. The reactor is then kept under an inert atmosphere throughout the reaction. The medium is stirred and operated at a temperature of 25°C for 1 h. The reaction is then stopped by adding water.

[0146] The reaction medium, constituting the polymerized effluent, is separated into a solvent-rich effluent and a resin-rich effluent by coagulation of the resins with water. The resin-rich effluent is then dried in an oven at 150°C for 48 h. A resin is recovered in the form of an orange translucent solid.

[0147] These steps are reproduced by varying the mass ratio of the limonene stream to the stream rich in heavy compounds at the inlet of the resin synthesis step, the other parameters remaining unchanged. The resins obtained have the characteristics presented below ■

[0148] [Table 2]

[0149] Example 2

[0150] The preparation, pyrolysis and separation steps are carried out in the same way as in Example 1.

[0151] The stream rich in light compounds (4) of composition 34% by weight of toluene, 45% by weight of ethylbenzene, 0.3% by weight of cumene, 19.9% ​​by weight of styrene, 0.8% by weight of alphamethylstyrene feeds a resin synthesis step. This step is also fed by a biosourced limonene stream comprising 99% by weight of limonene. No solvent stream is added, the compounds present in the stream of light compounds, and in particular ethylbenzene and toluene, being in sufficient quantity to ensure this role.

[0152] Aluminum chloride (1.5 mol% relative to the content of limonene, alpha-methylstyrene and styrene monomers) is introduced into the reactor under an inert atmosphere. The reactor is then kept under an inert atmosphere throughout the reaction. The medium is stirred and operated at a temperature of 30°C for 1 h. The reaction is then stopped by adding water.

[0153] The reaction medium, constituting the polymerized effluent, is separated into a solvent-rich effluent and a resin-rich effluent by coagulation of the resins with water. The resin-rich effluent is then dried in an oven at 150°C for 48 h. A resin is recovered in the form of an orange translucent solid.

[0154] These steps are reproduced by varying the mass ratio of the limonene stream to the stream rich in light compounds at the inlet of the resin synthesis step, the other parameters remaining unchanged. The resins obtained have the characteristics presented below ■

[0155] [Table 3]

[0156] The process according to the invention therefore allows the manufacture of hydrocarbon resins from recycled and / or bio-sourced resources, these resins being able to be adjusted to measure to ensure good compatibility with the matrix, in particular elastomeric, in which they are intended to be incorporated.

[0157] Examples 3a to 3c

[0158] The preparation, pyrolysis and separation steps are carried out in the same way as in Example 1.

[0159] The stream rich in aromatic compounds (5) of composition 99% by weight of styrene, feeds a resin synthesis step. This step is also fed by a biosourced limonene stream comprising 99% by weight of limonene and a toluene stream. The toluene stream flow rate is such that the monomer concentration (styrene + limonene) is 30% by weight at the reactor inlet. Aluminum chloride (1.5 mol% relative to the limonene and styrene monomer content) is introduced into the reactor under an inert atmosphere. The reactor is then kept under an inert atmosphere throughout the reaction. The medium is stirred and operated at a temperature of 25°C for 1 h. The reaction is then stopped by adding water.

[0160] The reaction medium, constituting the polymerized effluent, is separated into a solvent-rich effluent and a resin-rich effluent by coagulation of the resins with water. The resin-rich effluent is then dried in an oven at 150°C for 48 h. A resin is recovered in the form of an orange translucent solid.

[0161] These steps are reproduced by varying the mass ratio of the limonene stream to the stream rich in aromatic compounds at the inlet of the resin synthesis step, the other parameters remaining unchanged. The resins obtained have the characteristics presented below ■

[0162] [Table 4]

[0163] The process according to the invention therefore allows the manufacture of hydrocarbon resins from recycled and / or bio-sourced resources, these resins being able to be adjusted to measure to ensure good compatibility with the matrix, in particular elastomeric, in which they are intended to be incorporated.

Claims

CLAIMS

1. Process for producing hydrocarbon resins from a feedstock of styrenic compounds, 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; b. A step of pyrolyzing 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 c. A step of separating the gaseous effluent into at least one stream rich in light compounds, one stream rich in aromatic compounds and one stream rich in heavy compounds d. A step of synthesizing resins comprising a polymerization section fed at least by a stream from step c) and by a stream of aliphatic compounds comprising at least 5% by weight of terpenic compounds of biosourced origin, followed by a finishing section and producing a polymerized effluent e.A treatment step comprising a section for separating the polymerized effluent from step c) 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. Process according to any one of the preceding claims in which the terpene compounds are chosen from terpenes comprising at most 20 carbon atoms, preferably chosen from the compounds limonene, alpha-pinene, beta-pinene, myrcene, farnesene and their mixtures, preferably chosen from the compounds limonene, alpha-pinene, beta-pinene and their mixtures and preferably are limonene.

4. A method according to any preceding claim wherein the charge of styrenic compounds is gradually heated during step a) at 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. A method according to any one of the preceding claims wherein the pyrolysis step 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.

6. A method according to any preceding claim wherein the pyrolysis step involves a microwave pyrolysis step.

7. A process according to any preceding claim wherein separation step c) is carried out by distillation.

8. Method according to the preceding claim in which, in step c), a first column fed with the gaseous effluent from step b) separates this effluent into a flow rich in light compounds and a raffinate, the latter being separated by means of a second column into a flow rich in aromatic compounds and a flow rich in heavy compounds.

9. Process according to claim 7 in which step c) is carried out in a single distillation column operated at a pressure of between 0.1 and 2.0 bar, preferably between 0.5 and 1.5 bar and more preferably between 0.5 and 1.1 bar, the distillation column being fed at the bottom of the column with at least the gaseous effluent from step b) and producing 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 aromatic compounds, said column having as its only heat supply said gaseous effluent from step b).

10. Process according to any one of the preceding claims in which the mass ratio of flow from step b) to the flow of aliphatic compounds 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.

11. A method according to any preceding claim wherein the polymerization section of resin synthesis step d) is also supplied by a stream of solvent chosen from aliphatic, aromatic, halogenated solvents and their mixtures.

12. Process according to any one of claims 1 to 10 supplied solely by the feedstock of styrenic compounds and the stream of aliphatic compounds comprising at least 5% by weight of terpenic compounds of biosourced origin, the solvent necessary in step d) being provided by at least one stream from step c) and / or at least a fraction of the pyrolysis oil from step b).

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

14. Process according to any one of the preceding claims in which the polymerization section is operated at a temperature ranging from +20 to +90°C, with a residence time of between 0.5 h and 4 h, in the presence of 0.1% to 2% by weight of catalyst relative to the weight of monomers at the inlet of the polymerization section and a mass ratio of flow from step b) to the flow of terpene compounds of biosourced origin such that the level of aromatic protons, determined by 1H NMR, is between 0.5% mol and 99% mol, preferably between 1% mol and 50% mol, preferably between 2% mol and 40% mol, preferably between 2% mol and 30% mol and the level of aliphatic protons, determined by 1H NMR, is between 99.5% mol and 1% mol, preferably between 99% mol and 50% mol, preferably between 98% mol and 70% mol.

15. Hydrocarbon resin obtained from the process according to any one of the preceding claims, said resin having the following characteristics ■ - a glass transition temperature (noted Tg) ranging from 20°C to 140°C; - a number-average molar mass of less than 5000 g / mol, preferably less than 4000 g / mol and more preferably less than 3000 g / mol; - a dispersity D of less than 3, preferably less than 2.5 and more preferably less than 2; - A rate of aromatic protons, determined by 1H NMR, between 0.5% mol and 99% mol, preferably between 1% mol and 50% mol, preferably between 2% mol and 40% mol, preferably between 2% mol and 30% mol and preferably between 2% mol and 20% mol; - A rate of aliphatic protons, determined by 1H NMR, between 1% mol and 99.5% mol, preferably between 50% mol and 99% mol, preferably between 70% mol and 98% mol - A rate of ethylenic protons, determined by 1H NMR, less than or equal to 10% mol, preferably less than or equal to 5% mol, preferably less than or equal to 4% mol, the sum of the rates of aromatic, aliphatic and ethylenic protons being equal to 100%.

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