FR3150465A1 - Process for the production of hydrocarbon resins from polystyrene residues and tire residues - Google Patents

Abstract

The invention relates to a process for producing hydrocarbon resins from a feedstock of styrenic compounds and a feedstock comprising rubber chips, the resin produced by this process and a rubber composition comprising such a resin. Fig. 1

Description

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

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.

Prior art

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

Within hydrocarbon resins, hydrocarbon resins having a high glass transition temperature (Tg) comprising both aliphatic functions 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 having a high Tg are known from the state of the art and described, for example, in documents WO2016/043851, US9139721 or FR2968006.

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.

While 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.

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 problem of adjusting the microstructure of the resins, and in particular of adjusting the rate of aromatic and aliphatic monomers.

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.

Detailed description of the invention

The invention relates to at least one process for producing hydrocarbon resins from a charge of styrenic compounds and a charge comprising rubber chips, said process comprising at least:

a. A step of preparing the charge of styrenic compounds so as to be able to feed this charge into the pyrolysis step;

b1. A step of pyrolysis of the charge 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;

c1. A step of separating the gaseous effluent from step b1) 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 pyrolysis of the charge comprising rubber chips carried out at a temperature between 300 and 900°C with an increasing temperature ramp, 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 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;

d. A resin synthesis step comprising a polymerization section supplied at least by a flow from step c1) and by the intermediate fraction 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.

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

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

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.

Preferably, 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.

Preferably, pyrolysis step b1) implements a microwave pyrolysis step.

Preferably, separation step c1) is carried out by distillation.

Preferably, the mass ratio of flow from step c1) 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.

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

In a preferred arrangement, the process according to the invention is fed only with 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.

The invention also relates to a resin prepared by the process according to any one of the preceding claims 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 5000g/mol, preferably less than 4000g/mol and more preferably less than 3000g/mol;

• a dispersity Đ of less than 3, preferably less than 2.5 and more preferably less than 2;

• A level of aromatic protons, determined by 1H NMR, between 0.5 mol% and 50 mol%, preferably between 2 mol% and 30 mol% and more preferably between 2 mol% and 20 mol%;

• A level of aliphatic protons, determined by 1H NMR, between 50 mol% and 99.5 mol%, preferably between 70 mol% and 98 mol%, preferably between 80 mol% and 98 mol%;

• 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 aromatic, aliphatic and ethylenic proton levels being equal to 100%. Preferably, the ethylenic proton level, determined by 1H NMR, is greater than or equal to 0.5 mol%, preferably greater than or equal to 1 mol%.

The invention also relates to a rubber composition based on at least one elastomeric matrix comprising at least 50 pce of a butadiene copolymer, a reinforcing filler, a crosslinking system and a hydrocarbon resin according to the invention, or prepared by the process according to the invention.

Preferably, the butadiene copolymer of the rubber composition according to the invention has a glass transition temperature Tg of less than 20°C, preferably between 20°C and 110°C.

The invention also relates to a vehicle tire, the tread of which comprises a rubber composition according to the invention.

Definitions

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.

By C _n compound is meant a compound comprising n carbon atoms. Similarly, by C _n -C _m compounds is meant a set of compounds comprising from n to m carbon atoms.

A heteroatom means an atom other than carbon or hydrogen, for example nitrogen, sulfur, oxygen.

A hydrocarbon compound means a compound consisting of carbon and hydrogen.

Process load

The method according to the invention is a method for producing hydrocarbon resins from a charge of styrene 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.

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

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 end-of-life rubber articles. The rubber articles are preferably freed from 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 ranging from 1 to 50 mm and more preferably ranging 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.

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).

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).

Preferably, the diene elastomer is an isoprene elastomer.

By "isoprene elastomer" is meant, in a known manner, a homopolymer or a copolymer of isoprene, in other words a diene elastomer chosen from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), the various isoprene copolymers and the mixtures of these elastomers. Among the isoprene copolymers, mention will be made in particular of isobutene-isoprene copolymers (butyl rubber - IIR), isoprene-styrene (SIR), isoprene-butadiene (BIR) or isoprene-butadiene-styrene (SBIR). 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, polyisoprenes having a rate (mol%) of cis-1,4 bonds greater than 90%, more preferably still greater than 98%, are preferably used. 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.

Preferably, the rubber chips come from tire treads, in particular from heavy-duty tire treads, the latter having high contents of diene elastomers, preferably isoprene, typically 60 to 100 pce of isoprene elastomers.

Step a) Preparation

The method according to the invention comprises a step of preparing the charge of styrene compounds. During this step, the charge of styrene compounds is conditioned to be able to supply the pyrolysis step b). This preparation step may comprise grinding, degassing, and temperature-setting operations in order to cause the plastic compounds to melt, 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 polystyrene charge) and the solid effluents (non-fusible debris such as metal debris, glass) are separated.

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.

Step b1) of pyrolysis of the charge of styrenic compounds

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

Pyrolysis means the thermal decomposition of compounds in an inert or oxygen-poor 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.

The feedstock is fed to a pyrolysis step, operated 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 operated at a temperature ranging from 300 to 900°C, preferably ranging from 300°C to 800°C.

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.

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.

The use of 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 avoid “over-cracking” the styrene product. The use of a microwave pyrolysis step will reduce the formation of styrene oligomers compared to a conventional pyrolysis step.

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

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

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.

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 feedstock of the pyrolysis step or used in step d) of resin synthesis.

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

Step c1) of separation of the gaseous effluent from step b1)

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 flow rich in light compounds, one flow rich in aromatics and one flow rich in heavy compounds.

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

The aromatic-rich stream mainly comprises aromatic compounds comprising 6 to 9 carbon atoms. The separation step c1) is carried out in such a way that the aromatic-rich stream comprises at least 99% by mass of styrene.

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

Preferably, separation step c1) is carried out by distillation.

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

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 of 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 of between -5°C and 10°C, preferably between -5°C and 5°C in order to condense the styrene possibly entrained with the light compounds. The condensed flow after subcooling is returned to the top of the column as reflux. The residual vapor fraction constitutes the flow rich in light compounds. This flow can then be recovered, for example in the form of energy. A first cooling allows to use as much of the cooling water at ambient temperature as cold utility and minimizes the use of specific cold utility to obtain subcooling, which favorably impacts the life cycle analysis of the process according to the invention.

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”.

In this variant and preferably, the distillation column is supplied 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 draw-off a flow rich in aromatics, said column having as its only heat input said gaseous effluent from step b1).

The gaseous effluent from step b1) 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.

By feeding the charge at the bottom of the column, the charge is rapidly cooled, thus limiting any possible styrene polymerization reactions. This feed 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 implemented 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.

A flow rich in aromatics is drawn off on an intermediate tray. This draw-off tray is located in the lower third of the distillation column, preferably 1 to 3 theoretical stages from the bottom tray. This draw-off at a low position in the column, slightly away from the bottom tray, limits the entrainment of heavy compounds in the flow rich in aromatics and limits the risk of fouling of subsequent equipment.

Preferably, and in order to further limit the risk of polymerization, a polymerization inhibitor of styrene into 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.

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.

Step b2) of pyrolysis of the charge comprising rubber chips

The feed comprising rubber chips feeds a rubber chip pyrolysis step carried out at a temperature between 300 and 900°C with an increasing temperature ramp, 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 ₄ -C ₁₂ olefinic monomers.

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.

A low residence time of the gas fraction compared to the residence time of the solid fraction makes it possible to improve 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 makes it possible to improve the desorption of volatile materials linked 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.

These specific 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.

In particular, the use of an increasing temperature ramp makes it possible to optimize the yield and selectivity of the pyrolysis reactions towards the monomers of interest. Preferably, the pyrolysis step is carried out with a temperature ramp of between 1 and 10°C/min.

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. The pyrolysis reactor can be any device in which the reaction can take place via the supply of heat, the supply of heat being able to be carried out in any manner known to those skilled in the art, for example by combustion, by electrical means or by radiation.

When the pyrolysis step is operated continuously or semi-continuously, it can be implemented in several zones operated at increasing temperatures so that the flow passing through these zones undergoes a temperature increase of between 1 and 10°C/min.

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 non-condensable 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.

Pyrolysis oil consists mainly of a mixture of hydrocarbons with a wide range of boiling points. The majority of these compounds are members of the family of alkane, olefin, naphthenes (cycloalkanes) and aromatics. Some species containing heteroatoms are also present.

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 - _C12 olefinic monomers, preferably at least 2% by weight of _C4 - _C12 olefinic monomers, more preferably at least 4% by weight.

Olefinic monomers are hydrocarbon compounds comprising unsaturated carbon-carbon bonds and capable of polymerizing under suitable conditions. Among these olefinic monomers, mention may be made of limonene, terpenes, aromatic olefins such as styrene, alpha-methylstyrene, indene, coumarone, linear or cyclic olefins such as dicyclopentadiene.

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

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

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

Step c2) separation of the oil from step b2)

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.

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 with a lower final boiling point (or cut point according to the terminology used in distillation) than the intermediate fraction. Raffinate means a heavier fraction, i.e. one with a higher final boiling point than the intermediate fraction.

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.

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 that may have a negative impact on the resin synthesis step.

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 α-pinene, β-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.

Preferably, the intermediate fraction resulting from step b2) comprises at most 2% by weight of element sulfur, 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.

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 _C4 - _C12 olefinic monomers and to limit the heteroatom content.

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 trimming.

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.

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

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.

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

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

Preferably, the purification treatment is carried out by passing the intermediate fraction over a fixed bed of silica, alumina, activated carbon, ion exchange resins or a mixture of these constituents. Very preferably, the purification treatment is carried out by passing the intermediate fraction over a fixed bed of alumina beads in order, in particular, to remove polar impurities therefrom.

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 more preferably less than 0.8% by weight.

The raffinate, rich in polyaromatics, can be valorized for the production of carbon black, for example through so-called “Blast Furnace” processes, whose properties and specifications are comparable to those of carbon black produced from traditional raw materials. It can be used for the manufacture of new rubber products, such as tires, conveyor belts or any rubber article.

The extract, low in compounds of interest for the resin synthesis stage 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).

Step d) resin synthesis

The process according to the invention comprises a resin synthesis step comprising a polymerization section supplied at least by a flow from step c1) and by the intermediate fraction from step c2), followed by a finishing section and producing a polymerized effluent.

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 whose molecular weight is greater than 5000 g/mol, as well as the microstructure. A dimer means 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 means a compound comprising three monomers linked by a covalent bond. A trimer may 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.

By feeding the resin synthesis step with at least one stream from step c1) 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.

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.

Preferably, the mass ratio of flow from step c1) 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.

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

Preferably, the solvent chosen from aliphatic, aromatic, halogenated solvents and their mixtures is chosen from C7-C10 aromatic solvents, C6-C8 aliphatic solvents and C1-C2 chlorinated solvents and their mixtures, preferentially from toluene, methylcyclohexane and dichloromethane.

Preferably, a fraction of the pyrolysis oil from step b1) is used as a solvent stream. Preferably, the process according to the invention is supplied only by the feedstock of styrene compounds and the intermediate fraction from step c2), the solvent required in step d) being supplied 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) supplying step d).

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 trimeric compounds.

The polymerization section is carried out 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 carried out in the presence of an acid catalyst, such as a Bronsted acid or Lewis acid. Said polymerization section can also be carried out in the presence of ligands, a co-catalyst, and/or a cationic polymerization initiator, for example of the proton or carbocation generator type.

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.

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

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.

The amount of catalyst, including possible ligands and co-ligands, is preferably within 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) entering the polymerization section.

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

This finishing section makes it possible to stop the polymerization reaction by adding a compound that 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 C1-C3 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.

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

When the stopper compound is water, the volume ratio of reaction medium to water in the finishing section is preferably between 20:1 and 10:1, preferably between 10:1 and 5:1 and more preferably between 5:1 and 1:1.

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.

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.

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.

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

The polymerized effluent then feeds the treatment stage.

Step e) treatment of polymerized effluent

The process 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.

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).

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.

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.

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 flow rate of resins in the resin-rich effluent to the flow rate of resins in the feed of the separation section, is preferably greater than 80%, 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.

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.

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.

The coagulation separation section is preferably operated with a coagulation solvent/medium to be coagulated volume ratio ranging from 1:1 to 10:1, preferably ranging from 2:1 to 5:1. The coagulation separation section is preferably operated at a temperature ranging from 5°C to 40°C.

The flow 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.

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 flow comprising mainly water. This extraction can be carried out in one or more stages, preferably in one to three stages.

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

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 can 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.

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) optionally 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.

Resins

• une température de transition vitreuse (notée Tg) allant de 20°C à 140°C ;
• une masse molaire en nombre inférieure à 5000 g/mol, de préférence inférieure à 4000 g/mol et de manière préférée inférieure à 3000 g/mol ;
• une dispersité Đ inférieure à 3, de préférence inférieure à 2,5 et de manière préférée inférieure à 2 ;

• Un taux de protons aromatiques, déterminé par RMN 1H, compris entre 0.5%mol et 50%mol, de préférence compris entre 2% mol et 30%mol et de manière préférée compris entre 2% mol et 20%mol ;
• Un taux de protons aliphatiques, déterminé par RMN 1H, compris entre 50%mol et 99.5%mol, de préférence compris entre 70%mol et 98%mol, de préférence compris entre 80%mol et 98%mol ;
• Un taux de protons éthyléniques, déterminé par RMN 1H, inférieur ou égal à 10%mol, de préférence inférieur ou égal à 5%mol, de préférence inférieur ou égal à 4%mol,

The present invention also relates to a hydrocarbon resin obtained from the process according to the invention, 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 more preferably less than 3000 g/mol;
• a dispersity Đ of less than 3, preferably less than 2.5 and more preferably less than 2;

• An aromatic proton rate, determined by 1H NMR, of between 0.5 mol% and 50 mol%, preferably of between 2 mol% and 30 mol% and more preferably of between 2 mol% and 20 mol%;
• A rate of aliphatic protons, determined by 1H NMR, between 50 mol% and 99.5 mol%, preferably between 70 mol% and 98 mol%, preferably between 80 mol% and 98 mol%;
• An ethylenic proton rate, 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 aromatic, aliphatic and ethylenic proton rates being equal to 100%. Preferably, the level of ethylenic protons, determined by 1H NMR, is greater than or equal to 0.5 mol%, preferably greater than or equal to 1 mol%.

The dried resins can then be shaped according to any method known to those skilled in the art, depending on the subsequent use of said resins. This shaping can be carried out for example by granulation. The method of obtaining the resin gives it rubber composition properties different from similar resins in terms of structure.

Rubber composition

The present invention also relates to a rubber composition based on at least one elastomeric matrix comprising at least 50 pce of a butadiene copolymer, a reinforcing filler, a crosslinking system and a hydrocarbon resin according to the invention.

Elastomer

The rubber composition according to the invention comprises at least 50 pce of a butadiene copolymer.

The butadiene copolymer is preferably a copolymer of butadiene and a vinylaromatic monomer. Suitable vinylaromatic compounds are, for example, styrene, ortho-, meta-, para-methylstyrene, the commercial mixture "vinyl-toluene", para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene. Preferably, the vinylaromatic monomer of the copolymer of butadiene and vinylaromatic monomer is styrene.

Preferably, the rubber composition according to the invention comprises at least 70 pce, preferably at least 90 pce of at least one butadiene copolymer, preferably a butadiene-styrene copolymer.

According to a particularly preferred embodiment of the invention, the butadiene copolymer has a glass transition temperature Tg of less than -20°C, preferably between -20°C and -110°C, more preferably between -60°C and -110°C, more preferably between -60°C and -90°C. Such elastomers are known to those skilled in the art and described for example in documents WO2015/185394 and WO2017/168099.

The rubber composition of the bandage according to the invention may also comprise at least one other elastomer, preferably at least one other diene elastomer.

By diene type elastomer, we recall that it must be understood that an elastomer is derived at least in part (i.e. a homopolymer or a copolymer) from diene monomers (monomers carrying two carbon-carbon double bonds, conjugated or not).

These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". "Essentially unsaturated" is generally understood to mean a diene elastomer derived at least in part from conjugated diene monomers, having a content of units or patterns of diene origin (conjugated dienes) which is greater than 15% (mol %); thus diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins such as EPDM do not fall within the preceding definition and can in particular be described as "essentially saturated" diene elastomers (low or very low content of patterns of diene origin, always less than 15% (mol %)). The diene elastomers included in the rubber composition according to the invention are preferably essentially unsaturated.

The diene elastomer is preferably a diene elastomer of the essentially unsaturated type, in particular a diene elastomer selected from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), polybutadienes (BR), isoprene copolymers and blends of these elastomers. Such copolymers are more preferably selected from the group consisting of isoprene-styrene copolymers (SIR) and blends of such copolymers.

The above diene elastomers can be, for example, block, random, sequenced, microsequenced, and can be prepared in dispersion or in solution; they can be coupled and/or star-shaped or even functionalized with a coupling and/or star-shaping or functionalizing agent, for example epoxidized.

Reinforcing charge

The rubber composition according to the invention preferably comprises a reinforcing filler. Any type of reinforcing filler known for its ability to reinforce an elastomeric composition usable for the manufacture of pneumatic tires may be used, for example an organic filler such as carbon black, a reinforcing inorganic filler such as silica, or a blend of these two types of filler, in particular a blend of carbon black and silica.

Suitable carbon blacks are all carbon blacks, in particular HAF, ISAF, SAF type blacks conventionally used in tires (so-called tire grade blacks). Among the latter, mention will be made more particularly of the reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades), such as for example blacks N115, N134, N234, N326, N330, N339, N347, N375, or even, depending on the intended applications, blacks of higher series (for example N660, N683, N772). The carbon blacks could for example already be incorporated into an isoprene elastomer in the form of a masterbatch (see for example applications WO 97/36724 or WO 99/16600). The BET specific surface area of carbon blacks is measured according to standard D6556-10 [multipoint method (minimum 5 points) – gas: nitrogen – relative pressure range P/P0: 0.1 to 0.3].

By "reinforcing inorganic filler" is meant in the present application, by definition, any inorganic or mineral filler (whatever its color and its natural or synthetic origin), also called "white" filler, "light" filler or even "non-black filler" as opposed to carbon black, capable of reinforcing on its own, without any other means than an intermediate coupling agent, a rubber composition intended for the manufacture of pneumatic tires, in other words capable of replacing, in its reinforcing function, a conventional tire-grade carbon black; such a filler is generally characterized, in a known manner, by the presence of hydroxyl groups (-OH) on its surface.

Suitable inorganic reinforcing fillers are, in particular, mineral fillers of the siliceous type, in particular silica (SiO ₂ ), or of the aluminous type, in particular alumina (Al ₂ O ₃ ). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET surface area and a CTAB specific surface area both of less than 450 m ² /g, preferably from 30 to 400 m ² /g. Examples of highly dispersible precipitated silicas (known as "HDS") include the silicas "Ultrasil 7000" and "Ultrasil 7005" from Degussa, the silicas "Zeosil 1165MP", "1135MP" and "1115MP" from Rhodia, the silica "Hi-Sil EZ150G" from PPG, the silicas "Zeopol 8715", "8745" and "8755" from Huber, and the silicas with a high specific surface area as described in application WO 03/16837.

The physical state in which the reinforcing inorganic filler is present is immaterial, whether in the form of powder, microbeads, granules, beads or any other suitable densified form. Of course, the term reinforcing inorganic filler also means mixtures of different reinforcing inorganic fillers, in particular highly dispersible siliceous and/or aluminous fillers.

The reinforcing inorganic filler used, in particular if it is silica, preferably has a BET surface area of between 45 and 400 m ² /g, more preferably between 60 and 300 m ² /g.

Preferably, the rubber composition according to the invention comprises from 1 to 100 phr, more preferably from 1 to 80 phr and more preferably from 1 to 60 phr of carbon black, the optimum being, in a known manner, different depending on the particular applications targeted: the level of reinforcement expected on a bicycle tire, for example, is of course lower than that required on a tire capable of rolling at high speed in a sustained manner, for example a motorcycle tire, a tire for a passenger vehicle or for a utility vehicle such as a heavy goods vehicle. In a preferred arrangement, the reinforcing filler mainly comprises carbon black, and preferably consists of carbon black.

Preferably, the rubber composition according to the invention comprises from 10 to 150 phr, preferably from 50 to 130 phr of silica. In a preferred arrangement, the reinforcing filler mainly comprises silica and preferably consists of silica.

To couple the reinforcing inorganic filler to the elastomer, it is possible optionally to use in a known manner an at least bifunctional coupling agent (or bonding agent) intended to ensure a sufficient connection, of a chemical and/or physical nature, between the inorganic filler (surface of its particles) and the elastomer, in particular organosilanes, or bifunctional polyorganosiloxanes.

In particular, polysulfurized silanes, known as "symmetrical" or "asymmetrical" depending on their particular structure, may be used, as described for example in applications WO03/002648 (or US 2005/016651) and WO03/002649 (or US 2005/016650).

Examples of polysulfurized silanes include, in particular, bis-(C1-C4)-alkoxyl-(C1-C4)-alkylsilyl-(C1-C4)-alkyl polysulfides (in particular disulfides, trisulfides or tetrasulfides), such as, for example, bis(3-trimethoxysilylpropyl) or bis(3-triethoxysilylpropyl) polysulfides. Among these compounds, bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated to TESPT, of formula [(C2H5O)3Si(CH2)3S2]2 or bis-(triethoxysilylpropyl) disulfide, abbreviated to TESPD, of formula [(C2H5O)3Si(CH2)3S]2, are used in particular. Also to be mentioned as preferred examples are polysulfides (in particular disulfides, trisulfides or tetrasulfides) of bis-(monoalkoxyl(C1-C4)-dialkyl(C1-C4)silylpropyl), more particularly bis-monoethoxydimethylsilylpropyl tetrasulfide as described in patent application US 2004/132880.

As a coupling agent other than polysulfurized alkoxysilane, mention may in particular be made of bifunctional POS (polyorganosiloxanes) or hydroxysilane polysulfides as described in patent applications WO 02/30939 and WO 02/31041, or silanes or POS bearing azo-dicarbonyl functional groups, as described for example in patent applications WO 2006/125532, WO 2006/125533, WO 2006/125534.

In the rubber compositions in accordance with the invention, the content of coupling agent is preferably in a range from 5 to 18% by weight relative to the quantity of silica, preferably in a range from 8 to 12% by weight relative to the quantity of silica.

A person skilled in the art will understand that, as a filler equivalent to the reinforcing inorganic filler described in this paragraph, a reinforcing filler of another nature, in particular organic, could be used, provided that this reinforcing filler is covered with an inorganic layer such as silica, or else comprises functional sites on its surface, in particular hydroxyl sites, making it possible to establish the bond between the filler and the elastomer in the presence or absence of a covering or coupling agent.

Crosslinking system

The rubber composition according to the invention comprises a sulfur-based crosslinking system comprising a metal oxide, a stearic acid derivative and a vulcanization accelerator. This is then referred to as a vulcanization system. The sulfur can be provided in any form, in particular in the form of molecular sulfur, or a sulfur donor agent.

Sulfur is used at a rate ranging from 1 to 20 pce, preferably ranging from 1 to 10 pce.

The vulcanization accelerator is used at a preferential rate such that the sulfur/vulcanization accelerator mass ratio is less than or equal to 4.

Any compound capable of acting as an accelerator for the vulcanization of diene elastomers in the presence of sulfur may be used as an accelerator, in particular accelerators of the thiazole type and their derivatives, accelerators of the sulfenamide, thiuram, dithiocarbamate, dithiophosphate, thiourea and xanthate types. Examples of such accelerators include, but are not limited to, the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated as "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-tert-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-tert-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC"), and mixtures of these compounds.

The mass ratio of metal oxide to stearic acid derivative in the crosslinking system is less than 4, and preferably less than 3. The metal oxide is preferably zinc oxide.

The crosslinking system may also optionally include a vulcanization retarder.

The rubber compositions may preferably comprise additives commonly used in elastomeric compositions particularly intended for the manufacture of vehicle tires, such as, for example, pigments, protective agents, such as antiozonant waxes, chemical antiozonants or antioxidants, plasticizing agents other than those described above, antifatigue agents, reinforcing resins, or acceptors (for example, a phenolic novolac resin) or donors (for example HMT or H3M) of methylene.

The rubber compositions may further comprise a plasticizer system. This plasticizer system may be composed of a hydrocarbon-based resin having a Tg greater than 20°C, in addition to the specific hydrocarbon resin described above, and/or a plasticizer oil.

Preparation of rubber compositions

• une phase de travail ou malaxage thermomécanique, qui peut être conduite en une seule étape thermomécanique au cours de laquelle on introduit, dans un mélangeur approprié tel qu'un mélangeur interne usuel (par exemple de type 'Banbury'), tous les constituants nécessaires, notamment la matrice élastomérique, la résine hydrocarbure, les charges, les éventuels autres additifs divers. L’incorporation de la charge à l’élastomère peut être réalisée en une ou plusieurs fois en malaxant thermomécaniquement. Dans le cas où la charge, en particulier le noir de carbone ou la silice, est déjà incorporée en totalité ou en partie à l’élastomère sous la forme d’un mélange-maître (« masterbatch » en anglais) comme cela est décrit par exemple dans les demandes WO 97/36724 ou WO 99/16600, c’est le mélange-maître qui est directement malaxé et le cas échéant on incorpore les autres élastomères ou charges présents dans la composition qui ne sont pas sous la forme de mélange-maître, ainsi que les éventuels autres additifs divers.

The rubber composition according to the invention is manufactured in suitable mixers, using preparation phases well known to those skilled in the art:

• a thermomechanical working or mixing phase, which can be carried out in a single thermomechanical step during which all the necessary constituents, in particular the elastomeric matrix, the hydrocarbon resin, the fillers, and any other various additives, are introduced into a suitable mixer such as a conventional internal mixer (for example of the 'Banbury' type). The incorporation of the filler into the elastomer can be carried out in one or more stages by thermomechanical mixing. In the case where the filler, in particular carbon black or silica, is already incorporated in whole or in part into the elastomer in the form of a masterbatch as described for example in applications WO 97/36724 or WO 99/16600, it is the masterbatch which is directly mixed and where appropriate the other elastomers or fillers present in the composition which are not in the form of a masterbatch are incorporated, as well as any other miscellaneous additives.

• une seconde phase de travail mécanique est ensuite réalisée dans un mélangeur externe tel qu'un mélangeur à cylindres, après refroidissement du mélange obtenu au cours de la première phase jusqu'à une plus basse température, typiquement inférieure à 120°C, par exemple entre 40°C et 100°C.

Thermomechanical mixing is carried out at high temperature, up to a maximum temperature of between 110°C and 200°C, preferably between 130°C and 185°C, for a duration generally of between 2 and 10 minutes.

• a second phase of mechanical working is then carried out in an external mixer such as a roller mixer, after cooling the mixture obtained during the first phase to a lower temperature, typically below 120°C, for example between 40°C and 100°C.

The possible crosslinking system will be added during the second phase. For example, a crosslinking system based on polyacids or polydienophiles will typically be added during the first phase. A crosslinking system based on peroxides or sulfur will typically be added during the second phase.

The final composition thus obtained can then be calendered, for example in the form of a sheet or a plate, in particular for characterization in the laboratory, or even extruded in the form of a semi-finished (or profile) rubber.

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

The cooking can be carried out, in a manner known to those skilled in the art, at a temperature generally between 130°C and 200°C, under pressure, for a sufficient time which can vary for example between 5 and 90 min depending in particular on the cooking temperature, the crosslinking system adopted, the crosslinking kinetics of the composition considered or even the size of the vehicle tire.

Vehicle bandage

The present invention also relates to a vehicle tire, the tread of which comprises a rubber composition according to the invention.

The vehicle tire may be a pneumatic or non-pneumatic tire. Non-pneumatic means that the tire is capable of supporting the load of the vehicle by means other than a pressurized inflation gas, for example by means of guy wires.

The vehicle tire according to the invention will be chosen from, without limitation, tires intended to equip a two-wheeled vehicle, a passenger vehicle, a “heavy load” vehicle (i.e., a subway, a bus, off-road vehicles, heavy load transport vehicles, such as trucks, tractors or trailers), an aircraft, construction equipment, a heavy agricultural vehicle or a handling vehicle.

As known to those skilled in the art, the tread is the part of the vehicle tire which circumferentially surrounds this tire and ensures contact of the tire with the rolling surface, for example the road.

Measurement methods Glass transition temperature

The glass transition temperature Tg is measured in a known manner by differential scanning calorimetry, or DSC, for example and unless otherwise specified, according to the ISO 11357-2 standard of 2014.

Macrostructure (Mw, Mn, Mz and Đ)

The macrostructure (mass-average molar mass, number-average molar mass, and polydispersity index, respectively denoted Mw, Mn, Mz, and Đ) is determined by size exclusion chromatography (SEC) as shown below. The 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 share 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, the largest being eluted first. The sample to be analyzed is simply previously solubilized in an appropriate solvent, tetrahydrofuran at a concentration of 1.5 g/liter. Then the solution is filtered on 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.

A Moore calibration is conducted with a series of commercial standards of low Đ 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 Đ = Mw/Mn, are deduced.

All molar mass values indicated in this application therefore relate to calibration curves produced with polystyrene standards.

Molar distribution 1H _aliphatic /1H _ethylenic /1H _aromatic

The molar distribution of aliphatic, ethylenic and aromatic protons is measured using a spectrometer, here a Brucker AVANCE III 400Mhz spectrometer and is expressed in raw peak area ratios. The solvent used is a CDCl3 solvent (deuterated chloroform) at 25°C and 120 scans.

The NMR data of the hydrocarbon resin are measured by dissolving 20±1mg of sample in 0.7ml of solvents. The samples are dissolved in a 5mm NMR tube at 25°C until the sample is dissolved. CDCl3 is present as a peak at 7.20ppm and is used as a reference peak for the samples. The 1H NMR signals of the aromatic protons are located between 8.5ppm and 6.2ppm. The ethylenic protons lead to signals between 6.2ppm and 4.5ppm. Finally, the signals corresponding to aliphatic protons are located between 4.5ppm and 0ppm. The signals corresponding to the solvent, water and other possible impurities are subtracted when integrating the resin signals.

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.

Dynamic Properties

The dynamic properties of tan(δ) at 23°C and 100°C are measured on a viscoanalyzer (Metravib VA4000), according to the ASTM D 5992-96 standard. The response of a sample of crosslinked composition (cylindrical specimen 4 mm thick and 400 mm² in section) is recorded, subjected to a sinusoidal stress in alternating simple shear, at a frequency of 10 Hz, under the defined temperature conditions, at 23°C and 100°C, according to the ASTM D 1349-99 standard. A strain amplitude sweep is carried out from 0.1 to 50% (forward cycle), then from 50% to 1% (return cycle). The results used are the loss factor tan(δ) and the complex modulus G*. For the return cycle, the maximum value of tan(δ) observed and the value of G* are indicated. The tan(δ) value measured at 100°C is an indicator of dry grip. A high value indicates improved grip. The tan(δ) value measured at 23°C is an indicator of rolling resistance. A low value indicates lower rolling resistance.

Description of figures

There represents a schematic view of the method according to the invention.

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.

The gaseous effluent (3) is then treated in a separation step c1) in which it is separated into at least one stream rich in light compounds (7), a stream rich in aromatics (6) and a stream rich in heavy compounds (5).

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

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).

At least one of the streams (5), (6) or (7) and the intermediate fraction (13) feed a resin synthesis step d) 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).

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).

Example

Example of a process according to the invention and resin produced by this process

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

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 flow 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.

A charge comprising rubber chips (8), here chips from tire treads having an average diameter of approximately 1 mm and having an isoprene elastomer content of 65% by weight, feeds a pyrolysis step b2). This step is carried out under an inert nitrogen atmosphere, in a reactor composed of 3 sections heated independently to temperatures of 425°C, 550°C and 775°C respectively.

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): 13.5%, 44.5% and 42%. The pyrolysis oil (9) comprises approximately 4% by weight of several monomers of interest, including styrene, methylstyrene, indene, beta-pinene and limonene.

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 cut is separated, the initial boiling point of which is less than 160°C, constituting the extract (14). The heavier fraction feeds a second section for producing a raffinate (12) the cutting point of which is 280°C, i.e. the initial boiling point of which is 280°C at atmospheric pressure, and an intermediate cut constituting the intermediate fraction (13). The content of olefinic monomers in this fraction is approximately 33% by weight, including 24.3% by weight of limonene, 2.8% by weight of styrene and 3% by weight of indene.

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

The intermediate fraction (13) feeds, with the flow rich in heavy compounds (5), a resin synthesis step d). This step is also fed by a solvent flow (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 flow rich in heavy compounds (5), the intermediate fraction (13) and the solvent flow (15).

Aluminum chloride (2mol% relative to the content of limonene, styrene, indene, methylstyrene and beta-pinene monomers) is introduced into a 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 2 h. The reaction is then stopped by adding water.

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.

This C1 resin has the following characteristics:

Features C1 Glass transition temperature (Tg, °C) 35 Number average molar mass (Mn, g/mol) 590 Polydispersity index (Đ) 1.8 Molar distribution 1H _aliphatic / 1H _ethylenic / 1H _aromatic 91 / 3 / 7

Table 2 presents a commercial hydrocarbon resin derived from bio-sourced materials. Resin T1 is a bio-sourced resin derived from the polymerization of limonene, whose commercial reference is “Dercolyte L120” from the company DRT.

Features T1 Glass transition temperature (Tg, °C) 72-76°C Molar mass in number (Mn, g/mol) 690 Weight average molar mass (Mz, g/mol) 1186 Polydispersity index (Đ) 1.7 Molar distribution 1H _aliphatic / 1H _ethylenic / 1H _aromatic 97 / 2 / 1

Examples of rubber compositions

Rubber compositions are manufactured with the introduction of all the constituents on an internal mixer, with the exception of the vulcanization system. The vulcanization agents (sulfur and accelerator) are introduced on an external mixer at low temperature (the rollers constituting the mixer being at 30 °C). The compositions are cured under pressure at 150 °C for 40 minutes.

Table 3 shows different rubber compositions using the resins presented in Tables 1 and 2 as well as some of their properties.

Table 3 References

(1a) SBR of Tg = -88°C as described in the examples of WO2017/168099

(1b) SBR of Tg = -48°C as described in the examples of WO2015/185394(2) Carbon black, grade ASTM N234

(3) Silica, “Zeosil 1165 MP” from Solvay, type HDS

(4)N-(1,3-Dimethylbutyl)-N’-phenyl-p-phenylenediamine (“Santoflex 6-PPD”) from Flexsys and 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ)

(5) Coupling agent: “Si69” from Evonik – Degussa

(6) Diphenylguanidine, “Perkacit DPG” from Flexsys

(7) Stearin, “Pristerene 4931” from Uniqema

(8) Zinc oxide, industrial grade – Umicore

(9) N-Cyclohexyl-2-benzothiazolesulfenamide (“Santocure CBS” from Flexsys)

The results are expressed in base 100, with the value of 100 being assigned to the controls CT1 and CT2. A value greater than 100 indicates that the value of the corresponding property is greater than that of the control. A value less than 100 indicates that the value of the corresponding property is less than that of the control.

Compared to compositions based on a bio-sourced poly-limonene resin, it is observed that the compositions in accordance with the invention exhibit improved performance in terms of grip on dry ground, rolling resistance and G* rigidity. These performance differences are particularly interesting for a tread of a vehicle bandage.

Claims (15)

Process for producing hydrocarbon resins from a charge of styrenic compounds and a charge comprising rubber chips, said process comprising at least:
a. A step of preparing the charge of styrenic compounds so as to be able to feed this charge into the pyrolysis step;
b1. A step of pyrolysis of the charge 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;
c1. A step of separating the gaseous effluent from step b1) 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 pyrolysis of the charge comprising rubber chips carried out at a temperature between 300 and 900°C with an increasing temperature ramp, 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 ₄ -C ₁₂ olefinic monomers;
c2. 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;
d. A resin synthesis step comprising a polymerization section supplied at least by a flow from step c1) and by the intermediate fraction 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. Process 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. Method according to any one of the preceding claims in which the rubber chips comprise at least 50 phr of diene elastomer, preferably at least 60 phr of diene elastomer. 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. Process according to any one of the preceding claims, in which 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. Method according to any one of the preceding claims in which the pyrolysis step b1) implements a microwave pyrolysis step. Process according to any one of the preceding claims, in which separation step c1) is carried out by distillation. Process according to any one of the preceding claims, in which the mass ratio of flow from step c1) 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. Process according to any one of the preceding claims, in which the polymerization section of resin synthesis step d) is also supplied with a solvent stream chosen from aliphatic, aromatic, halogenated solvents and their mixtures. Process according to any one of claims 1 to 8 supplied only with the charge of styrenic compounds and the charge comprising rubber chips, the solvent necessary 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). 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. Resin prepared by the process according to any one of the preceding claims 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 more preferably less than 3000 g/mol;
• a dispersity Đ of less than 3, preferably less than 2.5 and more preferably less than 2;

• An aromatic proton rate, determined by 1H NMR, of between 0.5 mol% and 50 mol%, preferably of between 2 mol% and 30 mol% and more preferably of between 2 mol% and 20 mol%;
• A rate of aliphatic protons, determined by 1H NMR, between 50 mol% and 99.5 mol%, preferably between 70 mol% and 98 mol%, preferably between 80 mol% and 98 mol%;
• An ethylenic proton rate, 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 aromatic, aliphatic and ethylenic proton rates being equal to 100%. Preferably, the level of ethylenic protons, determined by 1H NMR, is greater than or equal to 0.5 mol%, preferably greater than or equal to 1 mol%. Rubber composition based on at least one elastomeric matrix comprising at least 50 pce of a butadiene copolymer, a reinforcing filler, a crosslinking system and a hydrocarbon resin according to the preceding claim, or prepared by the process according to any one of claims 1 to 11. Rubber composition according to the preceding claim in which the butadiene copolymer has a glass transition temperature Tg of less than -20°C, preferably between -20°C and -110°C. Vehicle tire, the tread of which comprises a rubber composition according to one of claims 13 or 14.