FR3150466A1 - HYDROCARBON RESIN FROM BIOSOURCED AND/OR RECYCLED MATERIALS AND RUBBER COMPOSITION COMPRISING THIS HYDROCARBON RESIN - Google Patents

Abstract

The invention relates to a hydrocarbon resin based on an aromatic distillation cut originating from the pyrolysis of a styrenic feedstock and then its separation into a styrene-rich stream comprising at least 99% by mass of styrene and an aliphatic stream of biosourced origin. Fig. 1

Description

HYDROCARBON RESIN DERIVED FROM BIO-BASED AND/OR RECYCLED MATERIALS AND RUBBER COMPOSITION COMPRISING THIS HYDROCARBON RESIN Technical field of the invention

The present invention relates to the field of hydrocarbon resins, rubber compositions comprising such resins, and vehicle tires comprising such rubber compositions.

Previous art

It is known from the prior art that elastomers with low glass transition temperature (“Tg”) allow for an improvement in terms of abrasion performance (WO 2015/043902) and are therefore very useful when seeking to obtain the best compromise between performance properties that are difficult to reconcile simultaneously, such as wear resistance and adhesion, which must be high, and rolling resistance, which must be low in order to minimize fuel consumption.

These low Tg elastomers exhibit poor compatibility with hydrocarbon-based plasticizing resins typically used in vehicle tires.

However, the compatibility of the resins with the elastomeric matrix, and in particular their ability to disperse properly in the mixture, is essential for them to perform their function 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 to aliphatic motifs of the resin (see, for example, J. Appl Polym. Sci 2022 139(15) 51950). Resins containing aliphatic and aromatic motifs and exhibiting high glass transition temperatures (Tg) allow, in particular, for the modification of the glass transition temperature of the mixture.

Such resins are well known in the prior art. For example, EP 0 936 229 describes the manufacture of hydrocarbon resins from aliphatic and aromatic monomers by cationic polymerization, using petroleum-based streams. WO2016/043851, US9139721, and FR2968006 describe hydrocarbon resins with high Tg values. FR 3 099 166 describes a tire comprising a rubber compound including a specific hydrocarbon resin derived from petroleum fractions, exhibiting improved road performance at various temperatures.

While the performance of pneumatic tires such as rolling resistance and wear resistance are key to limiting their environmental impact, it is also important to minimize the use of fossil resources in the manufacture of rubber products.

Documents WO2022/101562 and WO2022/101563 describe the production of hydrocarbon resins from residues of rubber chip pyrolysis. These documents do not address the impact of these resins on the performance of rubber compositions.

Continuing its research, the applicant discovered that a resin derived from bio-based and/or recycled resources made it possible to maintain, or even improve, key performance characteristics of rubber compositions usable in vehicle tires, thus being able to advantageously replace petroleum-based hydrocarbon resins.

Detailed description of the invention

The invention relates to a hydrocarbon resin based on an aromatic distillation cut obtained from the pyrolysis of a styrenic feedstock and its separation into a styrene-rich stream comprising at least 99% by mass of styrene and an aliphatic stream of bio-based origin, said resin having the following characteristics:

• a glass transition temperature (denoted Tg) ranging from 20°C to 140°C;

• a number molar mass less than 5000 g/mol;

• a dispersity Đ less than 3;

• An aromatic proton level, determined by 1H NMR, between 0.5%mol and 50%mol;

• An aliphatic proton level, determined by 1H NMR, between 50%mol and 99.5%mol;

• A level of ethylenic protons, determined by 1H NMR, less than or equal to 10%mol;

The sum of the levels of aromatic, aliphatic and ethylenic protons being equal to 100%.

Preferably, the aromatic proton level, determined by 1H NMR, is between 2% mol and 30% mol and preferably is between 2% mol and 20% mol.

Preferably, the styrenic compound charge comprises at least 90% by weight of polystyrene, preferably at least 93% by weight of polystyrene, and preferably at least 95% by weight of polystyrene.

Preferably, the hydrocarbon resin according to the invention is obtained by a process comprising at least:

a. A step of preparing the styrenic compound feedstock so that this feedstock can be supplied in the pyrolysis step;

b. A pyrolysis step of the styrenic compound feedstock enabling the production of 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 styrene-rich stream comprising at least 99% by mass of styrene;

d. A resin synthesis step comprising a polymerization section fed by the styrene-rich stream from step c) and by an aliphatic compound stream comprising at least 5% by weight of bio-based terpene compounds, 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 by the resin-rich effluent to produce a hydrocarbon resin stream.

The invention also relates to a rubber composition based on at least one elastomer and a hydrocarbon resin according to the invention.

The rubber composition according to the invention preferably comprises a reinforcing filler and a crosslinking system.

The rubber composition according to the invention preferably comprises 10 to 150 parts per annum, preferably 50 to 130 parts per annum of silica.

The elastomer of the rubber composition according to the invention is preferably a diene elastomer.

The rubber composition according to the invention preferably comprises predominantly a diene elastomer having a glass transition temperature Tg below -20°C, preferably between -20°C and -110°C.

The rubber composition according to the invention comprises at least 60 parts, preferably at least 70 parts, preferably at least 80 parts of at least one diene elastomer selected from the group consisting of polybutadiene, butadiene copolymers and mixtures of these elastomers.

Preferably, the butadiene copolymer is a butadiene-styrene copolymer.

The invention also relates to a vehicle tire comprising a rubber composition according to the invention or a resin according to the invention.

The vehicle tire according to the invention preferably comprises a tread comprising a hydrocarbon resin according to the invention or a rubber composition according to the invention.

Definitions

The carbon-containing compounds mentioned in the description can be of fossil origin or bio-based. In the latter case, they may be partially or entirely derived from biomass or obtained from renewable raw materials derived from biomass. This includes, in particular, polymers, plasticizers, fillers, etc.

The term "composition based on" refers to a composition comprising a mixture and/or the product of the in situ reaction of the various basic constituents used. Some of these constituents may react and/or are intended to react with each other, at least partially, during the various stages of manufacturing the composition or during the subsequent curing process, which may alter the composition as initially prepared. Consequently, the compositions described below may differ in the uncrosslinked and crosslinked states.

Unless expressly stated otherwise, all percentages (%) shown are percentages by weight (“% by weight”). In addition, any range of values designated by the expression “between a and b” represents the range of values extending from more than a to less than b (i.e., the limits a and b are excluded), while any range of values designated by the expression “from a to b” represents the range of values extending from a to b (i.e., including the strict limits a and b).

A _Cn compound is defined as a compound containing n carbon atoms. Similarly, _Cn - _Cm compounds are defined as a set of compounds containing from n to m carbon atoms.

By heteroatom, we mean an atom other than carbon or hydrogen, for example nitrogen, sulfur, oxygen.

A compound is said to be predominant when it represents more than 50% by weight of the compounds of the same type. Thus, a major elastomer is an elastomer that represents more than 50% by weight relative to the total weight of the elastomers present.

Hydrocarbon resin

• 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 relates to a hydrocarbon resin obtained from a feedstock of styrenic compounds and a stream of aliphatic compounds of bio-based origin, said resin having the following characteristics:

• a glass transition temperature (denoted Tg) ranging from 20°C to 140°C;
• a number molar mass less than 5000 g/mol, preferably less than 4000 g/mol and preferably less than 3000 g/mol;
• a dispersion Đ less than 3, preferably less than 2.5 and preferably less than 2;
• An aromatic proton level, determined by 1H NMR, between 0.5%mol and 50%mol, preferably between 2%mol and 30%mol and preferably between 2%mol and 20%mol;
• An aliphatic proton level, 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 content, 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%. 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 hydrocarbon resin according to the invention is based on an aromatic distillation cut from the pyrolysis of a styrenic feedstock and its separation into a styrene-rich stream comprising at least 99% by mass of styrene and an aliphatic stream of bio-based origin.

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

Preferably, the styrene compound filler is 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 preferably at least 95% by weight of polystyrene. The styrene compound filler may include other compounds, particularly if it is derived from plastic waste. These other compounds may be, but are not limited to, plastic compounds such as polyethylene, polypropylene, and elastomers; organic materials such as paper and food; or inorganic materials such as glass, metal, and sand.

The aliphatic compound stream includes at least 5% by weight of terpene compounds, of bio-based origin.

The aliphatic compound stream is bio-based. That is to say, it comes from biomass or is derived from biomass products.

By "derived from biomass," we mean that the compounds are obtained, after possible processing, from plant, animal, fungal, or microbial organisms. Preferably, the aliphatic compound stream is derived from plant organisms. By "derived from biomass products," we mean that the biomass used to obtain the aliphatic compound stream may have undergone processing such as biological processing, based, for example, on the functioning of plants, animals, or microorganisms; chemical processing, such as treatment with acid or alkali, with or without a catalyst; and/or physical processing such as pressurization, thermal processing, electromagnetic processing, or microwave processing.

Obtaining the resin

The hydrocarbon resin according to the invention can be obtained by the process described below.

Step a) of preparation

The styrenic compound feedstock is conditioned in a preparation step (a) to feed the pyrolysis step (b). This preparation step may include grinding, degassing, and heating operations to induce the melting of the plastic compounds, for example in an extrusion device during which the temperature is gradually increased, and the vapor effluents (water, light compounds generated by the partial decomposition of the polystyrene charge) and solid effluents (non-fusible debris such as metal fragments, glass) are separated.

Preferably, the styrenic compound charge is gradually heated to a temperature between 100°C and 300°C, preferably between 150°C and 300°C and preferably between 200°C and 300°C, this temperature allowing the polystyrene to melt, when such a compound is present, while limiting its thermal decomposition.

Step b) of pyrolysis

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

Pyrolysis refers to the thermal decomposition of compounds in an inert atmosphere.

The feedstock powers a pyrolysis step, operated at a temperature and pressure such that the depolymerization of styrenic compounds into styrene oligomers and styrene monomers 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 stage 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 preferably ranging from 1 bar to 4.5 bar.

Preferably, the pyrolysis step incorporates a microwave pyrolysis step. Such a microwave pyrolysis suitable for the pyrolysis of a styrenic compound feedstock is described, for example, in document WO 2020/202089.

The use of a microwave-assisted pyrolysis step allows for higher heat transfer rates and reaction temperatures, which promote chain-end cleavage reactions and minimize the formation of styrene oligomers. A microwave pyrolysis step is also characterized by a lower temperature in the reaction mass compared to a conventional pyrolysis section. Lower temperatures in the reaction mass lead to reduced evaporation rates of styrene oligomers and prevent over-cracking of the styrene produced. Therefore, using a microwave pyrolysis step will reduce styrene oligomer formation compared to a conventional pyrolysis step.

The pyrolysis step produces at least one gaseous effluent and one 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 light aromatic compounds gaseous under operating conditions, such as alpha-methylstyrene, 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 include solid elements, unfused polymers produced during pyrolysis, or debris not separated in the feed preparation step. This stream preferably feeds a separation section where any remaining solid fraction is separated from the liquid fraction, the latter being either recycled by mixing with the pyrolysis step feed or used in resin synthesis step d).

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

Step c) of separation

A separation step c) is fed at least by the gaseous effluent from step b) and produces at least one stream rich in light compounds, one stream rich in styrene and one stream rich in heavy compounds.

The stream rich in light compounds consists mainly of compounds lighter than styrene, particularly toluene and ethylbenzene.

The light compound-rich stream is a T100°C-140°C cut, preferably a T110°C-140°C cut. By "Ta°C-b°C cut," we mean that the bubble point and dew point of the cut, measured at atmospheric pressure, are within the temperature range of a°C to b°C. The light compound-rich stream therefore has a bubble point and dew point, measured at atmospheric pressure, within the temperature range of 100 to 140°C, preferably from 110 to 140°C.

Preferably, the cumulative content of toluene and ethylbenzene in the light compound-rich stream is at least 60% by mass, preferably at least 70% by mass, and preferably at least 75% by mass.

The styrene-rich stream consists mainly of aromatic compounds comprising 6 to 9 carbon atoms. Separation step c) is carried out in such a way that the styrene-rich stream comprises at least 99% by mass of styrene and that the styrene recovery rate, i.e. the ratio of the styrene flow rate in the aromatic-rich stream 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 preferably at least equal to 97%.

Preferably, the aromatic compound-rich stream is a T140°C-150°C cut, preferably a T144°C-146°C cut.

The heavy compound-rich stream mainly comprises compounds heavier than styrene, as well as undepolymerized styrenic compounds, and in particular styrene oligomers when the filler includes polystyrene.

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

Preferably, the alpha-methylstyrene content in the heavy compound-rich stream is at least 60% by mass, preferably at least 70% by mass, preferably at least 80% by mass, and most preferably at least 90% by mass.

Preferably, step c) of separation is carried out by distillation.

In a first variant of this preferred arrangement, a first column fed by 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 styrene and a stream 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 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 that may have been carried along with the lighter 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 lighter compounds. This stream can then be utilized, for example, as an energy source. An initial cooling allows maximum use of ambient temperature cooling water as a cold utility and minimizes the use of specific cold utility to achieve subcooling, which favorably impacts the life cycle analysis of the process.

In this variant, the distillation column is operated at a pressure between 0.1 and 2.0 bara, preferably between 0.5 and 1.5 bara, and most preferably between 0.5 and 1.1 bar, the operating pressure being understood as the pressure measured at the top of the column. "Bara" is understood to mean absolute bar, as opposed to pressure expressed in relative bar, commonly denoted "barg" according to the English notation "bar gauge".

In this variant and preferably, the distillation column is fed at the bottom of the column by 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 styrene, the said column having as its sole heat input the said gaseous effluent from step b).

The gaseous effluent from step b) is at a high temperature, preferably 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, it is rapidly cooled, thus limiting potential styrene polymerization reactions. This feeding method also allows for better management of 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 reduces the risk of fouling by heavy, particularly viscous compounds.

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

A styrene-rich stream is drawn off onto an intermediate tray. This drawing-off tray is located in the lower third of the distillation column, preferably one to three theoretical stages below the bottom tray. Drawing off at a low position in the column, slightly away from the bottom tray, limits the entrainment of heavy compounds in the styrene-rich stream and thus reduces the risk of fouling of subsequent equipment.

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

Compounds such as toluene and ethylbenzene, which do not react in step d) of resin synthesis, can be used as a solvent in this synthesis step, thus avoiding the addition of a solvent of external origin to the process.

Step d) of resin synthesis

A resin synthesis step d) comprising a polymerization section is fed by the styrene-rich stream from step c) and by an aliphatic compound stream comprising at least 5% by weight of bio-based terpene compounds, followed by a finishing section and producing a polymerized effluent.

The resin synthesis step mainly consists of oligomerizing the monomers in the styrene-rich stream from step c), particularly styrene and alpha-methylstyrene, and the aliphatic compound stream containing at least 5% by weight of bio-based terpene compounds. This process prepares new oligomeric resin-type materials by controlling the macrostructure, specifically by limiting the content of low molecular weight compounds such as monomers, dimers, and trimers, and high molecular weight compounds (i.e., those with a molecular weight greater than 5000 g/mol), as well as the microstructure. A dimer is defined as 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 homodimers and heterodimers. A trimer is a compound consisting of three monomers linked by a covalent bond. A trimer can be a homotrimer, that is, the combination of three identical monomers, a heterotrimer, that is, the combination of at least two different monomers, or a mixture of homotrimers and heterotrimers.

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

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

By feeding the resin synthesis step with the aromatic-rich stream from step c) and a stream of aliphatic compounds, the ratio of aromatic to aliphatic motifs in the produced resin can be controlled, thus tailoring the resin to the polymer matrix into which it is intended to be incorporated. This allows for the production of a highly compatible resin made from renewable and/or recycled resources.

Thus, the process allows the styrene-rich stream to be used according to the desired parameters for the resin produced, resulting in great versatility. Preferably, when the styrene-rich stream is produced by distillation in step c), no further treatment is required before using this stream for resin production.

Preferably, the mass ratio of the flux from step c) to the flux of aliphatic compounds feeding step d) is adjusted to regulate the proportion of aliphatic and aromatic protons in the resin.

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

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

Preferably, a fraction of the pyrolysis oil from step b) is used as a solvent stream. Preferably, the process is fed solely with the styrenic compound feed and the aliphatic compound stream comprising at least 5% by weight of bio-based terpenic compounds, the solvent required in step d) being supplied by at least one stream from step c) and/or at least a fraction of the pyrolysis oil from step b), preferably at least a fraction of the pyrolysis oil from step b) feeding step d).

Preferably, synthesis step d) is fed with the stream from step c) and a stream of aliphatic compounds comprising at least 5 wt% of terpene compounds, and a solvent stream such that the monomer content is between 50 and 75 wt%. This allows the solvent flow rate to be adjusted to control the monomer content in step d). This concentration limits exothermic reaction in step d) while still producing a polymerized effluent with a viscosity suitable for conveying to the downstream steps of the process.

Preferably, the resin obtained by the process comprises less than 1% by weight of compounds with a molecular mass greater than 5000 g/mol. Preferably, the resin obtained comprises at most 50% by weight of dimeric and trimer compounds.

The polymerization step is carried out in the absence of a catalyst, or in the presence of an acid catalyst, such as Brønsted acid, Lewis acid, or Friedel-Crafts acid, said catalyst being homogeneous or heterogeneous. Preferably, said polymerization step is carried out in the presence of an acid catalyst, such as Brønsted acid or Lewis acid. Said polymerization step may also be carried out in the presence of ligands, a co-catalyst, and/or a cationic polymerization initiator, for example, a proton generator or a carbocation initiator.

Preferably, the catalyst is a Lewis acid comprising ligands from the aluminum halide family. These ligands are preferably selected from aluminum chlorides, such as aluminum trichloride, alkylaluminum chlorides, such as diethylaluminum chloride and ethylaluminum dichloride, and arylaluminum chlorides, such as phenylaluminum chloride. Preferably, the catalyst also includes a Lewis base co-ligand, allowing for modulation of the acidic character of the Lewis acid ligand. This co-ligand may be an aliphatic ether (e.g., diethyl ether, dibutyl ether), an aromatic ether (diphenyl ether), an ester (ethyl acetate), an alkylamine (triethylamine), or an arylamine (diphenylamine, triphenylamine). The polymerization step can also be performed with ligands containing phosphorus, sulfur, or any other heteroatom.

The polymerization section is preferably carried out at a temperature ranging from -60°C to +300°C, preferably from -60°C to +120°C, very preferably from -50°C to +100°C and preferably from -40°C to +90°C and very preferably 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 volumetric flow rate of the feeds of the section.

The amount of catalyst, including any ligands and co-ligands, is preferably within a range of 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 entering the polymerization section.

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

This finishing section stops the polymerization reaction by adding a compound that deactivates the catalyst and halts any still-growing chains. The finishing section is preferably implemented by contacting the mixture with a stream containing a stopping compound chosen from water, a C1-C3 alcohol and mixtures thereof, preferably from water, methanol, ethanol and mixtures thereof, most preferably water, at a temperature between 5 and 80°C, preferably at a temperature between 15 and 30°C (for example, at ambient temperature), followed by phase separation by sedimentation of a polymerized effluent and an effluent consisting mainly of the stopping 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 stopping 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 preferably between 5:1 and 1:1.

The stream from the polymerization section and the stream including the stopper compound are brought into contact under agitation for a period preferably ranging from 5 min to 2 h, preferably ranging from 15 min to 45 min, in order to promote contact of the stopper compound with the reaction medium.

At the end of this agitation phase, a settling 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 low molecular weight oligomers and a phase containing mainly the stop compound, the catalytic residues and organic residues soluble in the stop compound.

The settling phase is preferably carried out for a period of 5 min to 4 h, preferably from 15 min to 2 h.

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

The polymerized effluent then feeds into the treatment stage.

Step e) of polymerized effluent treatment

The process includes a step of treating the polymerized effluent from step d) comprising a section for separating a solvent-rich effluent from a resin-rich effluent, and a drying section fed by the resin-rich effluent to produce the resins.

The implementation of the polymerized effluent treatment step in the process allows adjustment of the characteristics of the resins, in particular by eliminating low molecular weight oligomers (dimers, trimers, tetramers for example) and by reducing dispersity, in order to control the properties of the resins obtained (glass transition temperature for example).

The section separating a solvent-rich effluent from a resin-rich effluent allows, on the one hand, the recovery of a majority of the solvent and unconverted monomers for later use, preferably for recycling in the resin synthesis stage of the process, and on the other hand, the concentration of 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 to produce a solvent-rich effluent at the top and a resin-rich effluent at the bottom. This section removes residual monomers and oligomers at the top, as well as the majority of the solvent used in the resin synthesis step, thus adjusting the resin macrostructure and its properties, such as the glass transition temperature (Tg), notably by reducing dispersity through the removal of low molecular weight compounds. The resin-rich effluent contains the majority of the resins fed to 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 separation section feed, is preferably greater than 80%, and 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.

In another preferred arrangement, the separation section is carried out by resin coagulation. In this arrangement, the polymerized effluent from step d) is contacted with a coagulation solvent in which the resins are insoluble 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 among the low boiling point protic or aprotic polar solvents 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 volume ratio of coagulation solvent to medium to be coagulated 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 stream including the coagulation solvent, constituting the solvent-rich effluent, can then be recycled, for example to the resin synthesis stage, after 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 step d) is washed with a stream consisting mainly of water. This extraction can be carried out in one or more steps, preferably in one to three steps.

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

In another preferred arrangement, the separation section is achieved by evaporation, for example by evaporation in a scraped film evaporator.

The viscosity of the resin-rich effluent depends on its resin content and temperature. These contents and temperatures are therefore adjusted to allow the effluent to be transported to the drying section. One approach is to maintain a high temperature to ensure a high resin content while preserving a viscosity sufficient for transport, taking care to remain below the temperatures at which the resins begin to degrade thermally.

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

The hydrocarbon resin content in the rubber compound can range from 15% to 150%, 25% to 120%, 40% to 115%, 50% to 110%, and 65% to 110%. Below 15% of this hydrocarbon resin, its effect becomes insufficient, and the rubber compound may exhibit adhesion problems. Above 150%, the compound may present manufacturing difficulties due to the difficulty of incorporating this hydrocarbon resin into the compound.

Rubber composition

The present invention also relates to a rubber composition based on at least one elastomer and a hydrocarbon resin according to the invention. This rubber composition may further comprise various optional components, well known to those skilled in the art. Some of these are also described below.

Elastomer

The rubber composition according to the invention comprises at least one elastomer, preferably a diene elastomer. By diene elastomer, it is recalled that an elastomer which is derived at least in part (i.e. a homopolymer or a copolymer) from diene monomers (monomers bearing two carbon-carbon double bonds, conjugated or not).

These diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated." Generally, "essentially unsaturated" refers to a diene elastomer derived at least in part from conjugated diene monomers, having a proportion of diene-derived motifs or units (conjugated dienes) greater than 15% (mole percent). Thus, diene elastomers such as butyl rubbers or EPDM-type diene-alpha-olefin copolymers do not fall under the preceding definition and can be described, in particular, as "essentially saturated" diene elastomers (low or very low proportion of diene-derived motifs, always less than 15% (mole percent)). The diene elastomers included in the rubber composition according to the invention are preferably essentially unsaturated.

1. tout homopolymère d’un monomère diène, conjugué ou non, ayant de 4 à 18 atomes de carbone ;
2. tout copolymère d'un diène, conjugué ou non, ayant de 4 à 18 atomes de carbone et d’au moins un autre monomère.

The term diene elastomer, which can be used in rubber compositions according to the invention, is particularly understood to mean:

1. any homopolymer of a diene monomer, conjugated or not, having from 4 to 18 carbon atoms;
2. any copolymer of a diene, conjugated or not, having from 4 to 18 carbon atoms and at least one other monomer.

The other monomer can be ethylene, an olefin or a diene, conjugated or not.

Suitable conjugated dienes are those with 4 to 12 carbon atoms, in particular 1,3-dienes, such as 1,3-butadiene and isoprene.

Suitable olefins include vinylaromatic compounds with 8 to 20 carbon atoms and aliphatic α-monoolefins with 3 to 12 carbon atoms.

Examples of suitable vinylaromatic compounds include styrene, ortho-, meta-, para-methylstyrene, the commercial "vinyl-toluene" mixture, and para-tert-butylstyrene.

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

The diene elastomer is preferably a highly unsaturated diene elastomer, in particular a diene elastomer selected from the group consisting of natural rubber (NR), synthetic polyisoprenes (IR), polybutadienes (BR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers. Such copolymers are more preferably selected from the group consisting of butadiene-styrene copolymers (SBR), isoprene-butadiene copolymers (BIR), isoprene-styrene copolymers (SIR), isoprene-butadiene-styrene copolymers (SBIR), ethylene-butadiene copolymers (EBR), and mixtures of such copolymers.

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

By "isoprene elastomer" is meant a homopolymer or a copolymer of isoprene, in other words a diene elastomer chosen from the group consisting of natural rubber (NR) which can be plasticized or peptized, synthetic polyisoprenes (IR), the various isoprene copolymers, in particular isoprene-styrene copolymers (SIR), isoprene-butadiene copolymers (BIR) or isoprene-butadiene-styrene copolymers (SBIR), and mixtures of these elastomers.

According to a particularly preferred embodiment of the invention, the elastomer is a diene elastomer having a glass transition temperature (Tg) below -20 °C, preferably between -20 °C and -110 °C, more preferably between -60 °C and -110 °C, and more preferably between -60 °C and -90 °C. Such elastomers are known to those skilled in the art and are described, for example, in documents WO2015/185394 and WO2017/168099.

Preferably, the predominant diene elastomer is chosen from the group consisting of polybutadiene, butadiene copolymers and mixtures of these elastomers, and more preferably from the group consisting of polybutadiene, butadiene and styrene copolymers and mixtures of these elastomers.

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

According to this embodiment, the predominant elastomer, preferably diene, having a very low Tg, is present in the composition at a content preferably greater than or equal to 60 parts per cubic meter, more preferably greater than or equal to 70 parts per cubic meter, and even more preferably greater than or equal to 80 parts per cubic meter. More preferably, the composition comprises 100 parts per cubic meter of elastomer having a very low Tg as defined above.

Reinforcing load

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 can 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.

All carbon blacks are suitable, including those of the HAF, ISAF, and SAF types conventionally used in tires (so-called tire-grade blacks). Among these, carbon blacks of the 100, 200, or 300 series (ASTM grades) are particularly noteworthy, such as N115, N134, N234, N326, N330, N339, N347, and N375, or, depending on the intended application, blacks of higher series (e.g., N660, N683, N772). 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 specific surface area BET 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].

In this application, "reinforcing inorganic filler" should be understood by definition as any inorganic or mineral filler (regardless of its color and whether natural or synthetic), 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 carbon black of pneumatic grade; such a filler is generally characterized, in a known way, by the presence of hydroxyl groups (-OH) on its surface.

Suitable inorganic reinforcing fillers include mineral fillers of the siliceous type, particularly silica ( _SiO2 ), or of the aluminous type, particularly _alumina ( _Al2O3 ). The silica used may be any reinforcing silica known to those skilled in the art, including any precipitated or fumed silica having a BET surface area and a CTAB specific surface area both less than 450 ^m2 /g, preferably from 30 to 400 ^m2 /g. Examples of highly dispersible precipitated silicas (HDS) include, for instance, 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 silicas with a high specific surface area as described in application WO 03/16837.

The physical state of the reinforcing inorganic filler is irrelevant, whether it be in the form of powder, microbeads, granules, spheres, or any other suitable densified form. Of course, the term "reinforcing inorganic filler" also refers to mixtures of different reinforcing inorganic fillers, particularly highly dispersible siliceous and/or aluminous fillers.

The reinforcing inorganic filler used, especially if it is silica, preferably has a BET surface area of between 45 and 400 ^m² /g, more preferably between 60 and 300 ^m² /g.

Preferably, the rubber composition according to the invention comprises from 1 to 100 parts per annum, more preferably from 1 to 80 parts per annum, and preferably from 1 to 60 parts per annum of carbon black, the optimum being known to differ depending on the specific applications: the level of reinforcement expected on a bicycle tire, for example, is of course lower than that required on a tire suitable for sustained high-speed driving, for example, a motorcycle tire, a passenger car tire, or a commercial vehicle tire such as a truck. In a preferred arrangement, the reinforcing filler comprises predominantly carbon black, and preferably consists of carbon black.

Preferably, the rubber composition according to the invention comprises from 10 to 150 parts per cubic meter, preferably from 50 to 130 parts per cubic meter, of silica. In a preferred arrangement, the reinforcing filler comprises predominantly silica and preferably is made of silica.

To couple the reinforcing inorganic filler to the elastomer, one can optionally use in a known manner a coupling agent (or bonding agent) at least bifunctional 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, polysulfide silanes, described as "symmetric" or "asymmetric" depending on their particular structure, can 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 polysulfides (particularly disulfides, trisulfides, or tetrasulfides) of bis-(alkoxyl(C1-C4)-alkyl(C1-C4)silyl-alkyl(C1-C4)), such as bis(3-trimethoxysilylpropyl) or bis(3-triethoxysilylpropyl) polysulfides. Among these compounds, bis(3-triethoxysilylpropyl) tetrasulfide, abbreviated TESPT, with the formula [(C2H5O)3Si(CH2)3S2]2, and bis-(triethoxysilylpropyl) disulfide, abbreviated TESPD, with the formula [(C2H5O)3Si(CH2)3S]2, are particularly useful. We will also cite as preferential examples the polysulfides (in particular disulfides, trisulfides or tetrasulfides) of bis-(monoalkoxyl(C1-C4)-dialkyl(C1-C4)silylpropyl), more particularly the tetrasulfide of bis-monoethoxydimethylsilylpropyl as described in US patent application 2004/132880.

Examples of coupling agents other than polysulfurized alkoxysilane include 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 rubber compositions according to the invention, the coupling agent content is preferably in a range of 5 to 18% by weight relative to the amount of silica, preferably in a range of 8 to 12% by weight relative to the amount of silica.

Those skilled in the art will understand that, as an equivalent charge to the reinforcing inorganic charge described in this paragraph, a reinforcing charge of another nature, in particular organic, could be used, provided that this reinforcing charge is covered with an inorganic layer such as silica, or has functional sites on its surface, in particular hydroxyl sites, allowing the bond between the charge and the elastomer to be established in the presence or absence of a coating or coupling agent.

Crosslinking system

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

Sulfur is used at a rate of 1 to 20 parts per annum, preferably ranging from 1 to 10 parts per annum.

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 a vulcanization accelerator for diene elastomers in the presence of sulfur can be used as an accelerator, including thiazole-type accelerators and their derivatives, sulfenamide-type accelerators, thiurams, dithiocarbamates, dithiophosphates, thioureas and xanthates. Examples of such accelerators include the following compounds: 2-mercaptobenzothiazyl disulfide (abbreviated "MBTS"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-ter-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-ter-butyl-2-benzothiazyl sulfenimide ("TBSI"), tetrabenzylthiuram disulfide ("TBZTD"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds.

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.

Rubber compositions may preferably include additives commonly used in elastomeric compositions particularly intended for the manufacture of vehicle tires, such as, for example, pigments, protective agents, such as anti-ozone waxes, anti-ozonants or chemical antioxidants, plasticizers other than those described above, anti-fatigue agents, reinforcing resins, or acceptors (e.g., a novolac phenolic resin) or donors (e.g., HMT or H3M) of methylene.

Rubber compositions may also include a plasticizing system. This plasticizing system may consist of a hydrocarbon-based resin having a Tg greater than 20 °C, in addition to the specific hydrocarbon resin described above, and/or a plasticizing 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, including the elastomeric matrix, hydrocarbon resin, fillers, and any other miscellaneous additives, are introduced into a suitable mixer such as a standard internal mixer (e.g., of the Banbury type). The incorporation of the filler into the elastomer can be achieved 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, 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 between 110°C and 200°C, preferably between 130°C and 185°C, for a duration generally between 2 and 10 minutes.

• a second phase of mechanical work 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 crosslinking system, if desired, will be added during the second phase. For example, a polyacid- or polydienophile-based crosslinking system will typically be added during the first phase. A peroxide- or sulfur-based crosslinking system 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 plate, particularly for characterization in the laboratory, or extruded in the form of a semi-finished (or profile) of rubber.

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

The cooking process 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 minutes depending in particular on the cooking temperature, the crosslinking system adopted, the crosslinking kinetics of the composition considered, or the size of the tire.

Vehicle bandage

The present invention also relates to vehicle tires comprising a rubber composition based on at least one elastomer and a hydrocarbon resin according to the invention.

Vehicle tires can be pneumatic or non-pneumatic. Non-pneumatic means that the tire is capable of supporting the vehicle's load by means other than pressurized inflation gas, for example, by means of guy wires.

The vehicle tire according to the invention shall 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.

Preferably, the pneumatic tire according to the invention comprises a tread made of a rubber compound according to the invention or a hydrocarbon resin according to the invention. As is known to those skilled in the art, the tread is the portion of the pneumatic tire that circumferentially surrounds the tire and ensures contact with the rolling surface.

Description of the figures

FIG. 1 There FIG. 1 represents a schematic view of the process according to the invention.

A styrenic compound feedstock (1) is fed into a step a) for preparing the styrenic compound feedstock so that it can be fed (2) into the pyrolysis step b). The pyrolysis step b) of the styrenic compound feedstock yields 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 c) in which it is separated into at least one styrene-rich stream (5) comprising at least 99% by weight of styrene.

The stream (5) feeds a resin synthesis step d) comprising a polymerization section also fed at least by a stream (6) of aliphatic compounds comprising at least 5% by weight of terpenic compounds of bio-based origin, and possibly by a solvent stream (7), the polymerization section being followed by a finishing section producing a polymerized effluent (8).

The polymerized effluent (8) feeds a treatment step e) comprising a section for separating the polymerized effluent (8) from step d) into a solvent-rich effluent (9) and a resin-rich effluent, and a drying section fed by the resin-rich effluent to produce a hydrocarbon resin stream (10).

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 ISO 11357-2 of 2014.

Macrostructure (Mw, Mn, Mz and Đ)

The macrostructure (mass average molar mass, number average molar mass, centrifugation average molar mass, and polydispersity index, respectively denoted Mw, Mn, Mz, and Đ) is determined by size-exclusion chromatography (SEC) as described 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, involves separating macromolecules in solution according to their size using columns filled with a porous gel; the molecules are separated according to their hydrodynamic volume, with the largest being eluted first. The sample to be analyzed is simply pre-solubilized in a suitable solvent, tetrahydrofuran, at a concentration of 1.5 g/liter. The solution is then filtered through a 0.45 µm pore size filter before being injected into the instrument at a flow rate of 1 ml/min and a temperature of 35°C. The instrument used is, for example, a Waters Alliance chromatographic system.

A Moore calibration is performed using a series of commercial polystyrene standards with low ΔC (less than 1.2), of known molar masses, covering the range of masses to be analyzed. From the recorded data (mass distribution curve of molar masses), Mw, Mn, and ΔC = Mw/Mn are deduced.

All molar mass values indicated in this application are therefore relative to calibration curves made 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, in this case a Brucker AVANCE III 400 MHz spectrometer, and is expressed as ratios of crude peak areas. The solvent used is CDCl3 (deuterated chloroform) at 25°C and 120 scans.

The hydrocarbon resin NMR data are measured by dissolving 20 ± 1 mg of sample in 0.7 mL of solvent. The samples are dissolved in a 5 mm NMR tube at 25 °C until complete. CDCl3 is present as a peak at 7.20 ppm and is used as a reference peak for the samples. The 1H NMR signals of aromatic protons are located between 8.5 ppm and 6.2 ppm. Ethylene protons lead to signals between 6.2 ppm and 4.5 ppm. Finally, the 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 during the integration of the resin signals.

The areas of each category of protons are compared to the sum of these areas to give a percentage distribution of the area of each category of protons.

Dynamic properties

The dynamic properties of tan(δ) at 23°C and 100°C were measured on a viscoelastic analyzer (Metravib VA4000) according to ASTM D 5992-96. The response of a cross-linked composite sample (a 4 mm thick cylindrical specimen with a cross-sectional area of 400 mm²) was recorded under sinusoidal alternating shear at a frequency of 10 Hz, at the defined temperature conditions of 23°C and 100°C, according to ASTM D 1349-99. A strain amplitude sweep was performed from 0.1 to 50% (forward cycle), then from 50% to 1% (reverse cycle). The results used are the loss factor tan(δ). For the reverse cycle, the maximum observed value of tan(δ) is indicated. The tan(δ) value measured at 100°C indicates dry grip. A high value denotes improved grip. The tan(δ) value measured at 23°C indicates rolling resistance. A low value denotes lower rolling resistance.

The dynamic property tan(δ) at 0°C is measured on a viscoanalyzer (Metravib V A4000), according to ASTM D 5992-96. The response of a cross-linked composite sample (cylindrical specimen 4 mm thick and 10 mm in diameter) subjected to sinusoidal alternating simple shear loading at a frequency of 10 Hz is recorded during a temperature sweep from -80°C to +100°C with a ramp rate of +1.5°C/min.

A maximum stress of 0.7 MPa is applied. The tangent value of the loss angle (Tan delta) is then recorded at 0°C. The tan(δ) value measured at 0°C indicates wet grip. A high value denotes improved grip.

Traction tests

The tests were carried out in accordance with the French standard NF T 46-002 of September 1988. All tensile measurements were carried out under normal temperature (23±2°C) and humidity (50±5% relative humidity) conditions, according to the French standard NF T 40-101 (December 1979).

We measure the tensile strength (in MPa) and the elongation at break (AR in %), at 23°C ± 2°C, according to standard NF T 46-002, on samples baked for 40 minutes at 150°C. The energy at break is equal to the product of the elongation at break and the tensile strength.

Examples of resins

A styrenic compound feed (1), here polystyrene, feeds a preparation step a), here an extruder, in which it is heated to a temperature of 250°C. The liquid portion of the feed (2) feeds a pyrolysis step b), here microwave pyrolysis, operated at a temperature of 340°C and 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 light compound-rich stream (4), a styrene-rich stream (5) comprising 99.2% by weight of styrene, and a heavy compound-rich stream (6).

The styrene-rich stream (5), composed of 99% styrene by weight, feeds a resin synthesis step. This step is also fed by a bio-based limonene stream comprising 99% limonene by weight and a toluene stream. The toluene 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 maintained under an inert atmosphere throughout the reaction. The mixture is stirred and the reaction is carried out at a temperature of 25°C for 1 hour. The reaction is then stopped by the addition of water.

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 as a translucent orange solid.

These steps are reproduced by varying the mass ratio of the limonene flow to the styrene-rich flow at the inlet of the resin synthesis step, while the other parameters remain unchanged. The resulting resins exhibit the characteristics shown below:

Example 1a 1b 1c Mass ratio of limonene flux to styrene-rich flux 90/10 80/20 50/50 Glass transition temperature (Tg, °C) 60 62 64 Molar mass by number (Mn, g/mol) 650 730 930 Average molar mass in z (Mz, g/mol) 1900 2300 4100 Polydispersity index (Đ) 1.8 1.9 2.2 Molar distribution: 1H _aliphatic / 1H _ethylenic / 1H _aromatic 93 / 2 / 5 89 / 2 / 9 74 / 1 / 25

Table 2 presents commercial hydrocarbon resins. Resin T1 is a bio-based resin derived from the polymerization of limonene, "Dercolyte L120" from the company DRT. Resin T2 is a resin derived from the polymerization of dicyclopentadiene (DCPD), a petroleum-based resin, whose trade name is "Escorez 5600" from the company Exxon.

Example T1 T2 Glass transition temperature (Tg, °C) 72-76°C 51 Molar mass by number (Mn, g/mol) 690 488 Average molar mass by weight (Mz, g/mol) 1186 784 Polydispersity index (Đ) 1.7 1.6 Molar distribution: 1H _aliphatic / 1H _ethylenic / 1H _aromatic 97/2/1 90 / 0 / 10

Examples of rubber compositions

Rubber compounds are manufactured by introducing all the components onto an internal mixer, with the exception of the vulcanizing system. The vulcanizing agents (sulfur and accelerator) are introduced onto an external mixer at a low temperature (the mixer's rollers being at 30°C). The compounds are then 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.

CT1 CT2 C1 C2 C3 SBR (1) 100 100 100 100 100 Carbon black (2) 4 4 4 4 4 Silica (3) 130 130 130 130 130 T1 Resin 88 - - - - T2 Resin - 88 - - - Resin 1a - - 88 - - Resin 1b - - - 88 - Resin 1c - - - - 88 Antioxidant (4) 6 6 6 6 6 Coupling agent (5) 13 13 13 13 13 DPG (6) 2.5 2.5 2.5 2.5 2.5 Stearic acid (7) 3 3 3 3 3 ZnO (8) 0.9 0.9 0.9 0.9 0.9 Accelerator (9) 2.3 2.3 2.3 2.3 2.3 Soluble sulfur 0.7 0.7 0.7 0.7 0.7 Results (base 100) Tan(δ) at 0°C 100 91 101 99 95 Tan(δ) at 100°C 100 95 104 101 96 Tan(δ) at 23°C 100 86 95 95 109 Breaking energy at 23°C 100 117 106 115 140

References from Table 3(1) SBR of Tg = -88 °C as described in the examples of WO2017/168099(2) Carbon black, ASTM grade 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) Stearine, “Pristerene 4931” from Uniqema(8) Zinc oxide, industrial grade – Umicore(9) N-Cyclohexyl-2-benzothiazolesulfenamide (“Santocure CBS” from Flexsys)

The results are expressed on a scale of 100, with 100 assigned to the control CT1. 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 petroleum-based hydrocarbon resin or based on a bio-based poly-limonene resin, it is observed that the compositions according to the invention exhibit similar performance in terms of adhesion on dry and wet ground, similar rolling resistance and improved breaking energy.

Claims (13)

Hydrocarbon resin based on an aromatic distillation cut from the pyrolysis of a styrenic feedstock and its separation into a styrene-rich stream comprising at least 99% by mass of styrene and an aliphatic stream of bio-based origin, said resin having the following characteristics:

• a glass transition temperature (denoted Tg) ranging from 20°C to 140°C;
• a number molar mass less than 5000 g/mol;
• a dispersity Đ less than 3;
• An aromatic proton level, determined by 1H NMR, between 0.5%mol and 50%mol;
• An aliphatic proton level, determined by 1H NMR, between 50%mol and 99.5%mol;
• An ethylenic proton level, determined by 1H NMR, less than or equal to 10%mol;

The sum of the levels of aromatic, aliphatic and ethylenic protons being equal to 100%. Hydrocarbon resin according to the preceding claim in which the aromatic proton content, determined by 1H NMR, is between 2% mol and 30% mol and preferably is between 2% mol and 20% mol. Hydrocarbon resin according to any one of the preceding claims, wherein the styrenic compound charge comprises at least 90% by weight of polystyrene, preferably at least 93% by weight of polystyrene, and preferably at least 95% by weight of polystyrene. Hydrocarbon resin according to any one of the preceding claims obtained by a process comprising at least:

1. A step of preparing the styrenic compound feed so that this feed can be supplied in the pyrolysis step;
2. A pyrolysis step of the styrenic compound feedstock allowing the production of at least one gaseous effluent and one pyrolysis oil, said gaseous effluent comprising at least 20% by weight of aromatic compounds;
3. A step of separating the gaseous effluent into at least one styrene-rich stream comprising at least 99% by mass of styrene;
4. A resin synthesis step comprising a polymerization section fed by the styrene-rich stream from step c) and by an aliphatic compound stream comprising at least 5% by weight of bio-based terpene compounds, followed by a finishing section and producing a polymerized effluent;
5. 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 by the resin-rich effluent to produce a hydrocarbon resin stream.

Rubber composition based on at least one elastomer and a hydrocarbon resin according to any one of the preceding claims. Rubber composition according to the preceding claim comprising a reinforcing filler and a crosslinking system. Rubber composition according to any one of claims 5 to 6 comprising from 10 to 150 parts, preferably from 50 to 130 parts of silica. Rubber composition according to any one of claims 5 to 7 wherein the elastomer is a diene elastomer. Rubber composition according to any one of claims 5 to 8 wherein the elastomer predominantly comprises a diene elastomer having a glass transition temperature Tg below -20°C, preferably between -20°C and -110°C. Rubber composition according to any one of claims 5 to 9 comprising at least 60 parts, preferably at least 70 parts, preferably at least 80 parts of at least one diene elastomer selected from the group consisting of polybutadiene, butadiene copolymers and mixtures of these elastomers. Rubber composition according to the preceding claim wherein the butadiene copolymer is a butadiene-styrene copolymer. Vehicle bandage comprising a rubber composition according to any one of claims 5 to 11 or a resin according to any one of claims 1 to 4. Vehicle tire according to the preceding claim, wherein the tread comprises a hydrocarbon resin according to any one of claims 1 to 4 or a rubber composition according to any one of claims 5 to 11.