Process for the preparation of resins from rubber crumbs

Abstract

The invention relates to a process for the preparation of a hydrocarbon resin from a feed comprising rubber crumbs, said process comprising at least: a pyrolysis step and a resin synthesis step.

Description

Technical Field

[0001] This invention relates to the field of methods for recycling rubber products. Background Technology

[0002] Pneumatic tires, and more commonly rubber products (such as conveyor belts and non-pneumatic tires), are complex objects composed of a variety of components. For example, pneumatic tires are made up of more than 200 different raw materials.

[0003] Challenges related to renewable and fossil resources necessitate the full utilization of resources, exemplified by waste rubber products. To date, the recycling of materials from waste rubber products (e.g., used tires) into new tires remains limited, particularly due to the significant impact of their components on tire performance. In fact, the recycling of these materials can have a negative overall environmental impact due to the performance degradation of tires using them. Therefore, there is a strong need for a method to recycle rubber products at the end of their lifespan to prepare raw materials whose use does not degrade tire performance, thereby reducing the overall environmental impact.

[0004] Extensive research has been conducted in this field, particularly on the recycling of oil produced from the pyrolysis of waste tires. Therefore, documents EP 0928817, WO 2013 / 170358, and JP2017 / 008214 teach the preparation of tire-grade carbon black starting from the pyrolysis of tire scrap.

[0005] Other studies have examined the recycling of intermediates. Document WO 90 / 14409 relates to the separation of pyrolysis oil from waste tires by distillation to recover marketable chemicals (particularly limonene), with distillation to concentrate commercially beneficial compounds. The article "Production of dl-limonene by vacuum pyrolysis of used tires" itself teaches that the amount of limonene in the pyrolysis oil of tire scraps can be increased by adjusting the temperature of the pyrolysis step and minimizing the residence time of the gas phase in the reactor.

[0006] The literature “Areview of dipentene (dl-limonene) production from waste tire pyrolysis” (Danon et al., Journal of Analytical and Applied Pyrolysis 112(2015)1-13) also involves the preparation of dipentene from waste tires. None of these literatures address the subsequent use of these products. The literature “Thermal depolymerization and pyrolysis of cis-1,4-polyisoprene: preparation of liquid polyisoprene and terpene resin” (Cataldo, Journal of Analytical and Applied Pyrolysis 44(1998)121-130) involves the preparation of resins from the depolymerization products of pure isoprene, either natural or synthetic. However, the depolymerization of tire waste leads to many byproducts that are not present in the depolymerization of pure polyisoprene, and their effects may be detrimental to the preparation of the resin.

[0007] The purpose of this invention is to recycle the rubber scraps obtained from the product at the end of its lifespan to prepare raw materials, particularly resins, that can be used to manufacture new tires without affecting their performance. Summary of the Invention

[0008] The present invention relates to at least one of the following embodiments:

[0009] 1. A method for preparing a hydrocarbon-containing resin from a feed containing rubber scraps, the method comprising at least:

[0010] a. A step of pyrolyzing rubber scraps at a temperature between 300°C and 900°C at a certain heating rate, producing gaseous effluent, pyrolysis oil, and solid effluent, wherein the pyrolysis oil contains at least 1.5% by weight of C4-C. 12 Olefin monomers;

[0011] b. The step of separating the pyrolysis oil into at least one residue, a middle fraction, and an extract, said middle fraction comprising 10 to 90% by weight of C4-C. 12 Olefin monomers and up to 10% by weight of heteroatoms;

[0012] c. A resin synthesis step comprising: a polymerization stage supplied at least with an intermediate fraction obtained from step b), followed by a completion stage that produces a polymer effluent;

[0013] d. A step of processing the polymer effluent obtained from step c), comprising: a stage for separating the effluent rich in inert compounds and the effluent rich in resin, and a drying stage for producing a hydrocarbon-containing resin effluent from the supply of the resin-rich effluent.

[0014] No externally supplied inert compounds are supplied to the method for preparing hydrocarbon-containing resins, meaning that the inert compounds are not introduced into the resin in resin synthesis step c) and do not interact with the catalytic system.

[0015] 2. The method according to the preceding embodiment, wherein the rubber fragments have a maximum length in the range of 1 to 100 mm, preferably 1 to 50 mm, and more preferably 1 to 30 mm.

[0016] 3. The method according to any one of the foregoing embodiments, wherein the rubber scrap comprises at least 50 phr of diene elastomer.

[0017] 4. The method according to the preceding embodiment, wherein the diene elastomer is selected from natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymer, isoprene copolymer, and mixtures of these elastomers.

[0018] 5. The method according to any one of the foregoing embodiments, wherein the rubber fragments are derived from the tire tread.

[0019] 6. The method according to any one of the foregoing embodiments, wherein the pyrolysis step includes a pyrolysis reactor operated at a temperature between 350 and 800°C, a pressure less than 1 bar, and a solid-to-gas residence time ratio of 10 to 240, wherein the temperature is preferably between 350 and 650°C, and the solid-to-gas residence time ratio is preferably 10 to 120, and very preferably 10 to 60.

[0020] 7. The method according to any one of the foregoing embodiments, wherein an inert gas stream is supplied to the pyrolysis step.

[0021] 8. The method according to any one of the foregoing embodiments, wherein the residence time of the solid fraction in the pyrolysis step is 3 to 180 min, preferably 3 to 120 min.

[0022] 9. The method according to any one of the foregoing embodiments, wherein the pyrolysis step is carried out at a heating rate between 1 and 10 °C / min.

[0023] 10. The method according to any one of the foregoing embodiments, wherein the intermediate fraction obtained from step b) is a fraction with a boiling point of 140 to 280°C, preferably 150 to 280°C, and more preferably 150 to 260°C at atmospheric pressure.

[0024] 11. The method according to any one of the foregoing embodiments, wherein the intermediate fraction obtained from step b) contains at most 2% by weight, preferably at most 1.5% by weight, preferably less than 1% by weight, and very preferably less than 0.8% by weight of sulfur.

[0025] 12. The method according to any one of the foregoing embodiments, wherein separation step b is performed by distillation.

[0026] 13. The method according to the preceding embodiment, wherein the middle fraction is obtained by topping and then tailing.

[0027] 14. The method according to embodiment 12, wherein separation step b) is carried out in a column having an inner wall, and an intermediate fraction is obtained by extracting a side stream from the column.

[0028] 15. The method according to any one of embodiments 12 to 14, wherein step b is performed 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.

[0029] 16. The method according to any one of the foregoing embodiments, wherein the intermediate fraction obtained from step b) is purified before being supplied to step c).

[0030] 17. The method according to the preceding embodiment, wherein purification is performed by passing the intermediate fraction through a fixed bed containing silica, alumina, activated carbon, ion exchange resin, or a mixture of these components.

[0031] 18. The method according to one of the two preceding embodiments, wherein the content of heteroatoms in the middle fraction at the end of the purification process is less than 2% by weight, preferably less than 1% by weight, preferably less than 0.9% by weight, and preferably less than 0.8% by weight.

[0032] 19. The method according to any one of the foregoing embodiments, wherein the polymerization stage is carried out in the presence of an acid catalyst, preferably selected from Bronstein acid or Lewis acid type catalysts, and more preferably Lewis acids containing aluminum halide ligands.

[0033] 20. The method according to any one of the foregoing embodiments, wherein the polymerization stage is operated at a temperature of -60°C to 120°C, preferably -50°C to 100°C, and more preferably -40°C to 90°C.

[0034] 21. The method according to any one of the foregoing embodiments, wherein the average residence time in the polymerization stage is between 0.25 h and 6 h.

[0035] 22. The method according to any one of the foregoing embodiments, wherein the completion stage of step c) is carried out by contacting the stream containing the terminator compound at a temperature between 5°C and 80°C, and then separating the polymer effluent and the effluent mainly containing the terminator compound by phase decantation, wherein the terminator compound is selected from water, C1-C3 alcohols and mixtures thereof, preferably selected from water, methanol, ethanol and mixtures thereof, and very preferably water.

[0036] 23. The method according to the preceding embodiment when it is subordinate to embodiment 19, or according to the preceding embodiment when it is subordinate to both embodiment 19 and any one of embodiments 20 to 21, wherein the molar ratio of the terminator compound to the polymerization catalyst is at least equal to 2 in the completion phase.

[0037] 24. The method according to one of the two aforementioned embodiments, wherein the stirring contact between the stream from the polymerization stage and the stream containing the terminator compound is preferably for 5 min to 2 h, preferably 15 min to 45 min.

[0038] 25. The method according to one of the three aforementioned embodiments, wherein the separation by phase plethysmosis takes 5 minutes to 4 hours.

[0039] 26. The method according to any one of the foregoing embodiments, wherein the separation stage of the step of treating the polymer effluent is carried out by distillation, resin coagulation, liquid-liquid extraction or a combination of these methods.

[0040] 27. A finished or semi-finished rubber product comprising a resin obtained by the method according to any one of the foregoing embodiments.

[0041] 28. A pneumatic or non-pneumatic tire comprising a resin obtained by any one of embodiments 1 to 26.

[0042] definition

[0043] The carbon-containing compounds mentioned in this specification may be of fossil or biological origin. In the case of biological origin, they may be derived in whole or in part from biomass, or may be obtained from renewable raw materials derived from biomass.

[0044] C n A compound is defined as a compound containing n carbon atoms. Similarly, C n -C mA compound is defined as a group of compounds containing n to m carbon atoms.

[0045] Heteroatoms refer to atoms other than carbon or hydrogen, such as nitrogen, sulfur, and oxygen.

[0046] Feeding for the method

[0047] A feed comprising rubber fragments is supplied to the preparation method according to the present invention.

[0048] "Scrap material" refers to small components obtained by shredding rubber products (preferably waste rubber products). Non-rubber components, such as fabric fibers or metal wires, are preferably removed from the rubber products. The rubber scrap material preferably has a maximum length of 1 to 100 mm, more preferably 1 to 50 mm, and even more preferably 1 to 30 mm. The scrap material can be of any shape, but preferably has a relatively uniform size and shape to facilitate the pyrolysis step. This control over size and shape is well known to those skilled in the art.

[0049] Preferably, the rubber pellet contains at least 50 phr of diene elastomer. The term "diene" elastomer (or rubber in general) (whether natural or synthetic) itself means an elastomer that is at least partially (i.e., a homopolymer or copolymer) composed of diene monomer units (monomers with two conjugated or non-conjugated carbon-carbon double bonds).

[0050] Preferably, the diene elastomer is selected from polybutadiene (BR), natural rubber (NR), synthetic polyisoprene (IR), butadiene copolymers, isoprene copolymers, and mixtures of these elastomers. The butadiene copolymer is particularly selected from butadiene-styrene copolymer (SBR).

[0051] Preferably, the diene elastomer is an isoprene elastomer.

[0052] "Isoprene elastomer" refers, in a known manner, to homopolymers or copolymers of isoprene; in other words, it refers to diene elastomers selected from natural rubber (NR), synthetic polyisoprene (IR), various isoprene copolymers, and mixtures of these elastomers. Among isoprene copolymers, isobutylene-isoprene copolymers (butyl rubber-IIR), isoprene-styrene (SIR), isoprene-butadiene (BIR), or isoprene-butadiene-styrene (SBIR) may be specifically mentioned. The isoprene elastomer is preferably selected from natural rubber, synthetic cis-1,4 polyisoprene, and mixtures thereof; among these synthetic polyisoprene, polyisoprene with a cis-1,4 bond content (mol%) greater than 90%, and even more preferably greater than 98%, is preferred. Preferably, according to any of the arrangements herein, the diene elastomer is natural rubber.

[0053] High diene elastomer content is beneficial for producing monomers of interest, especially limonene, after pyrolysis.

[0054] Preferably, the rubber fragments are obtained from tire treads, particularly from the treads of heavy-duty truck tires, which have a high content of diene elastomer, preferably isoprene elastomer, typically 60 to 100 phr isoprene elastomer.

[0055] pyrolysis step a)

[0056] The process involves feeding a feed comprising rubber scraps into the following steps: pyrolyzing the rubber scraps at a temperature between 300°C and 900°C at a controlled heating rate to produce a gaseous effluent, pyrolysis oil, and a solid effluent, wherein the pyrolysis oil contains at least 1.5% by weight of C4-C. 12 Olefin monomers.

[0057] The pyrolysis step is preferably carried out at a temperature between 350 and 800°C, a pressure below 1 bar, and a solid-to-gas residence time ratio of 10 to 240. The temperature is preferably between 350 and 650°C, and the solid-to-gas residence time ratio is preferably between 10 and 120, and very preferably between 10 and 60.

[0058] The shorter residence time of the gaseous fraction compared to the solid fraction allows for improved yields of the monomers of interest. The residence time of the gaseous fraction can be reduced by supplying an inert gas to the pyrolysis step. This preferred supply also allows for improved desorption of volatile substances bound to the solid fraction.

[0059] In the pyrolysis step, the residence time of the solid fraction is preferably 3 to 180 min, more preferably 3 to 120 min. The residence time of the gas fraction is less than 3 min.

[0060] These specific conditions allow for the maximization of the production of compounds of interest, particularly monomers such as limonene, as well as gaseous fractions that can be sold as fuel and heavy liquid fractions that can be used to manufacture carbon black.

[0061] In particular, the use of heating rates allows for optimization of the yield and selectivity of the pyrolysis reaction for the monomer of interest. Preferably, the pyrolysis step is carried out at a heating rate between 1 and 10 °C / min.

[0062] The pyrolysis step can be carried out in a pyrolysis reactor and can be operated continuously, semi-continuously, or in batches. Such reactors are well known to those skilled in the art.

[0063] When the pyrolysis step is carried out continuously or semi-continuously, the pyrolysis step can be carried out in multiple heating operation zones, so that the flow passing through these zones experiences a temperature rise between 1 and 10 °C / min.

[0064] The effluent obtained from pyrolysis is cooled to condense the volatile fractions. At the end of condensation, three effluents are obtained: a gaseous effluent containing non-condensable gases (i.e., gaseous under normal temperature and pressure conditions (i.e., 0 °C and 1 atm)), a liquid effluent referred to by the term "pyrolysis oil", and a solid effluent.

[0065] Pyrolysis oil is mainly composed of a mixture of hydrocarbons with a wide boiling point range. Most of these compounds form part of the alkanes, alkenes, cycloalkanes, and aromatics groups. Some compounds containing heteroatoms also exist.

[0066] The operating conditions of the pyrolysis step according to the method of the present invention produce pyrolysis oil containing at least 1.5% by weight of C4-C. 12 Olefin monomers, preferably at least 2% by weight of C4-C 12 Olefin monomers, preferably at least 4% by weight of C4-C 12 Olefin monomers.

[0067] "Olefin monomer" refers to hydrocarbon compounds containing unsaturated carbon-carbon bonds that can polymerize under appropriate conditions. Among these olefin monomers, limonene, terpenes, aromatic olefins (e.g., styrene, α-methylstyrene, indene, coumarone), and linear or cyclic olefins (e.g., dicyclopentadiene) may be mentioned.

[0068] The pyrolysis oil preferably contains at least 70% by weight, preferably at least 74% by weight, and preferably at least 78% by weight of carbon.

[0069] The pyrolysis oil preferably contains up to 5% by weight, more preferably up to 3% by weight, and more preferably up to 1.5% by weight of nitrogen.

[0070] The pyrolysis oil preferably contains up to 2% by weight, more preferably up to 1.5% by weight, and more preferably up to 1% by weight of sulfur.

[0071] Step b) of separating pyrolysis oil

[0072] The method according to the invention comprises the following steps: separating pyrolysis oil into at least one residue, an intermediate fraction, and an extract, said intermediate fraction containing 10% to 90% by weight of C4-C. 12 Olefin monomers and up to 10% by weight of heteroatoms.

[0073] "Extract" refers to the lighter fraction, meaning its final boiling point (or fractionation point in the terminology of distillation) is lower than the initial boiling point of the middle fraction. "Residue" refers to the heavier fraction, meaning its initial boiling point is higher than the final boiling point of the middle fraction.

[0074] The olefin monomers contained in the pyrolysis oil obtained from the pyrolysis step cannot be directly polymerized. In fact, on the one hand, their concentration is too low, and on the other hand, many components contained in the oil may be detrimental to the proper operation of the resin synthesis steps, especially those related to catalyst activity.

[0075] Preferably, the intermediate fraction obtained from step b) is a fraction with a boiling point of 140 to 280°C, more preferably 150 to 280°C, and even more preferably 150 to 260°C at atmospheric pressure. This fraction concentrates most of the olefin monomers of interest while excluding most compounds that might negatively affect the resin synthesis steps.

[0076] The middle fraction contains 10% to 90% by weight of C4-C. 12 The olefin monomer and up to 10% by weight heteroatoms. Specifically, it contains limonene, other compounds of the terpene family (e.g., α-pinene, β-pinene, carene, myrcene, farnesene, other terpenes (whether oxidized or not)), aromatic olefins (e.g., styrene, α-methylstyrene, indene, coumarone), linear olefins, and cyclic olefins (e.g., dicyclopentadiene), and also contains compounds that are inert relative to the resin synthesis step, such as aliphatic and aromatic hydrocarbons. Preferably, separation step b) is performed such that the middle fraction contains 20% to 80% by weight of C4-C4 hydrocarbons. 12 Olefin monomers. The middle fraction is separated by removing extracts and residues, such that the content of inert compounds obtained in the middle fraction is 10% to 90% by weight, preferably 20% to 80% by weight. In this document, "inert compound" refers to a compound that does not react in the resin synthesis step, i.e., a compound that is not introduced into the resin and does not interact with the catalytic system. In this case, the compounds are primarily aliphatic and aromatic compounds, preferably aromatic hydrocarbon compounds and aliphatic hydrocarbon compounds, preferably linear or cyclic aliphatic hydrocarbon compounds, unsubstituted or monoaromatic compounds substituted with one or more alkyl groups, and polyaromatic compounds containing 2 to 5 aromatic rings. These inert compounds relative to the synthesis step preferably mainly comprise organic compounds containing 8 to 10 carbon atoms, preferably organic compounds containing 8 to 10 carbon atoms and an aromatic ring (having 6 carbon atoms). Among these inert compounds relative to the synthesis step, diethylbenzene, ethylmethylbenzene, and o-isopropylbenzane may be mentioned.

[0077] These inert compounds include only those compounds that are not gaseous under normal temperature and pressure conditions, and therefore do not include inert gases such as argon or nitrogen.

[0078] Preferably, the intermediate fraction obtained from step b) contains at most 2% by weight, preferably at most 1.5% by weight, preferably less than 1% by weight, and very preferably less than 0.8% by weight of sulfur, which is particularly unfavorable to the subsequent resin synthesis steps.

[0079] The step of separating pyrolysis oil into at least one residue, middle fraction, and extract can be performed by methods known to those skilled in the art that can increase C4-C content. 12 Any method that limits the concentration of olefin monomers and restricts the content of heteroatoms.

[0080] In particular and preferably, the separation step b) is carried out by distillation, which can be performed sequentially (in batches) or continuously in one or more intermediate steps.

[0081] Therefore, in the preferred arrangement, separation step b) is carried out by distillation, and the middle fraction is obtained by topping and then tailing.

[0082] "Removing the top" means removing the light distillate, which preferably has a fractionation point below 140°C, more preferably below 150°C at atmospheric pressure. "Removing the tail" means removing the heavy distillate, which preferably has a fractionation point above 280°C, more preferably above 260°C.

[0083] In another preferred arrangement, separation step b) is carried out by distillation, and the middle fraction is obtained by tailing and then topping.

[0084] In another preferred arrangement, separation step b) is performed in a single distillation step, with the middle fraction obtained by side-distillation from said distillation step. A particularly preferred example of implementing this arrangement is with a so-called "inner wall" column.

[0085] Residues rich in polyaromatic compounds can be used to produce carbon black (e.g., via the so-called "blast furnace" process), with properties and specifications comparable to carbon black obtained from conventional raw materials. It can be used to manufacture new rubber products such as tires, conveyor belts, or any rubber-based products.

[0086] For the resin synthesis step of the method of the present invention, extracts of compounds of interest in low concentrations can preferably be used as solvents, engine fuels, plasticizers, or can be processed during refining to utilize light aromatic hydrocarbons (benzene, toluene, xylene).

[0087] In a preferred embodiment of separation step b) by distillation, distillation is preferably carried out at a pressure less than or equal to atmospheric pressure, preferably less than or equal to 0.5 bar, and preferably less than or equal to 0.250 bar.

[0088] Preferably, the intermediate fraction obtained from step b) is purified before being supplied to step c).

[0089] Where applicable, this purification process particularly enables the reduction of the content of compounds such as sulfur or carbonyl compounds before the middle distillate is supplied to the resin synthesis step c).

[0090] Preferably, purification is performed by passing the middle fraction through a fixed bed containing silica, alumina, activated carbon, ion exchange resin, or a mixture of these components.

[0091] In the arrangement using purification treatment, the content of heteroatoms in the middle fraction at the end of the purification treatment is less than 2 wt%, preferably less than 1 wt%, preferably less than 0.9 wt%, and preferably less than 0.8 wt%.

[0092] Resin synthesis step c)

[0093] The method according to the invention includes a resin synthesis step comprising: a polymerization stage at least supplied with an intermediate fraction obtained from step b), followed by a completion stage that produces a polymer effluent.

[0094] The resin synthesis step mainly consists of the following: by controlling the macroscopic structure (especially by limiting the content of low molecular weight compounds (e.g., monomers, dimers, and trimers) and high molecular weight compounds (with molecular weights higher than 5000 g / mol)) and the microstructure, the olefin monomers contained in the intermediate fraction supplied to the synthesis step are oligomerized, thereby preparing novel resin-type oligomer materials. A dimer refers to a compound containing two monomers linked together by covalent bonds. A dimer can be a homodimer (i.e., a combination of two identical monomers), a heterodimer (i.e., a combination of two different monomers), or a mixture of homodimers and heterodimers. A trimer refers to a compound containing three monomers linked together by covalent bonds. A trimer can be a homotrimer (i.e., a combination of three identical monomers), a heterotrimer (i.e., a combination of at least two different monomers), or a mixture of homotrimers and heterotrimers.

[0095] No inert compounds, supplied from outside the method, are supplied to resin synthesis step c). These inert compounds, as understood herein, are compounds that do not react in the resin synthesis step, i.e., compounds that are not introduced into the resin and do not interact with the catalytic system. Therefore, the intermediate fraction obtained from step b) is supplied to step c), optionally by recycling the inert compound-rich effluent from step d), without requiring any additional supply of inert compounds as understood herein from outside the method.

[0096] Preferably, the resin obtained by the method according to the invention contains less than 1% by weight of a compound with a molecular weight greater than 5000 g / mol. Preferably, the obtained resin contains up to 50% by weight of dimer and trimer compounds.

[0097] The polymerization stage is carried out in the absence of a catalyst or in the presence of an acid catalyst of the type of Bronstein acid or Lewis acid, which may be homogeneous or heterogeneous. Preferably, the polymerization stage is carried out in the presence of an acid catalyst of the type of Bronstein acid or Lewis acid. The polymerization stage may also be carried out in the presence of a ligand, a co-catalyst, and / or a cationic polymerization initiator (e.g., a cationic polymerization initiator of the type that generates protons or carbocations).

[0098] Preferably, the catalyst is a Lewis acid containing aluminum halide ligands. Preferably, these ligands are selected from aluminum chlorides (e.g., aluminum trichloride), alkyl aluminum chlorides (e.g., diethylaluminum chloride and diethylaluminum dichloride), and aryl aluminum chlorides (e.g., phenylaluminum chloride). Preferably, the catalyst also includes co-ligands of the following types that have Lewis base properties (so that the acidity of the Lewis acid ligands can be tuned): aliphatic ether types, such as diethyl ether, dibutyl ether; aromatic ethers, such as diphenyl ether; or esters, such as ethyl acetate; or alkylamines, such as triethylamine, or arylamines, such as diphenylamine, triphenylamine. The polymerization stage can also be carried out using ligands containing phosphorus, sulfur, or any other heteroatoms.

[0099] The specific operation of separation step b) according to the method of the present invention enables the retention of sufficient amounts of inert compounds (especially aliphatic and aromatic compounds, preferably aromatic hydrocarbon compounds and aliphatic hydrocarbon compounds, preferably linear or cyclic aliphatic hydrocarbon compounds, unsubstituted or monoaromatic compounds substituted with one or more alkyl groups, and polyaromatic compounds containing 2 to 5 aromatic rings) in the middle fraction to carry out the resin synthesis step without the addition of exogenous inert compounds, while maintaining good conversion and good selectivity, particularly by well controlling the exothermic effect.

[0100] The polymerization stage is preferably carried out at temperatures ranging from -60°C to +300°C, more preferably from -60°C to +120°C, very preferably from -50°C to +100°C, more preferably from -40°C to +90°C, and very preferably from +20°C to +90°C.

[0101] The average residence time in the polymerization stage is preferably between 0.25 h and 7 h, more preferably between 0.5 h and 4 h. When the polymerization stage is operated continuously, the average residence time in the stage is the ratio of the reaction volume of the stage to the total volumetric flow rate of the feed material to the stage.

[0102] The amount of catalyst containing ligands and optional co-ligands relative to the C4-C atoms entering the polymerization stage. 12 The olefin monomer is preferably in the range of 0.05% to 5% by weight, and preferably relative to the C4-C atoms entering the polymerization stage. 12 The olefin monomers range from 0.1% to 2% by weight.

[0103] The flow from the aggregation stage is then processed in the completion stage to produce the aggregated effluent.

[0104] This completion stage allows the polymerization reaction to be stopped by adding a compound that deactivates the catalyst and terminates any remaining chains. The completion stage is preferably carried out by contacting the stream containing the terminator compound at a temperature between 5°C and 80°C, preferably between 15°C and 30°C (e.g., at room temperature), followed by phase decantation to separate the polymerization effluent from the effluent primarily containing the terminator compound, wherein the terminator compound is selected from water, C1-C3 alcohols, and mixtures thereof, preferably from water, methanol, ethanol, and mixtures thereof, with water being highly preferred.

[0105] In the completion stage, the molar ratio of the terminator compound to the polymerization catalyst is at least 1.1, preferably at least 2.

[0106] When the terminating compound is water, the volume ratio of the reaction mixture to water in the completion stage is preferably between 20:1 and 1:10, more preferably between 10:1 and 1:5, and more preferably between 5:1 and 1:1.

[0107] The flow from the polymerization stage and the flow containing the terminator compound are stirred and contacted for a period of 5 min to 2 h, preferably 15 min to 45 min, to promote contact between the terminator compound and the reaction mixture.

[0108] At the end of the stirring step, a decantation step is performed to separate the organic phase constituting the polymerization effluent, which mainly contains resin, inert compounds, unconverted monomers, dimers, trimers and low molecular weight oligomers, and the phase mainly containing terminator compounds, catalyst residues and organic residues soluble in terminator compounds (which constitutes an effluent mainly containing terminator compounds).

[0109] The decantation step is preferably performed for 5 minutes to 4 hours, and more preferably for 15 minutes to 2 hours.

[0110] The effluent, which mainly contains the terminator compound, can then be processed to recycle the terminator compound to the completion stage.

[0111] The polymer effluent is then supplied to the processing steps.

[0112] Step d) in the treatment of polymer effluent

[0113] The method according to the invention includes a step of treating the polymer effluent obtained from step c), the step comprising: a stage for separating the effluent rich in inert compounds and the effluent rich in resin, and a drying stage for producing resin from the resin-rich effluent supply.

[0114] By performing the step of treating the polymer effluent in the method according to the invention, the properties of the resin can be adjusted, particularly by removing low molecular weight oligomers (e.g., dimers, trimers, tetramers) and by reducing dispersibility, so as to control the properties of the obtained resin.

[0115] The stage for separating the effluent rich in inert compounds and the effluent rich in resin allows, on the one hand, the recovery of most of the inert compounds and unconverted monomers for subsequent use (preferably for recycling to the resin synthesis step according to the method of the invention), and on the other hand, the concentration of resin in the resin-rich effluent.

[0116] The separation stage can be carried out by any method known to those skilled in the art, particularly preferably by evaporation, distillation, resin coagulation, liquid-liquid extraction, or a combination of these methods.

[0117] In a preferred arrangement, the separation stage is implemented by distillation in at least one distillation column to produce an effluent rich in inert compounds at the top and a resin-rich effluent at the bottom. This stage allows for the removal of monomers and residual oligomers at the top, as well as most of the inert compounds that act as solvents in the polymerization steps used in the resin synthesis step. Therefore, dispersibility can be reduced, particularly by removing low molecular weight compounds, thereby adjusting the macrostructure and properties of the resin, such as its glass transition temperature (Tg). The resin-rich effluent contains the majority of the resin supplied to the separation stage. The resin recovery rate corresponds to the ratio of the resin flow rate in the resin-rich effluent to the resin flow rate in the feed to the separation stage, which is preferably greater than 80%, more preferably greater than 90%. This recovery rate can be adjusted by increasing the number of separation stages in the separation stage or by adjusting the operating parameters of said stage, such as the reflux ratio.

[0118] In another preferred arrangement, the separation stage is carried out by resin coagulation. In this arrangement, the polymer effluent from step c) is contacted with a coagulation solvent that does not dissolve the resin, so as to cause the resin to precipitate. The coagulation solvent dissolves residual monomers, inert compounds that act as solvents in the resin synthesis steps, and low molecular weight oligomers.

[0119] The solidification solvent is preferably selected from low-boiling protic or aprotic polar solvents, such as alcohols (e.g., methanol, ethanol and isopropanol), acetone, ethers (e.g., tetrahydrofuran (denoted as THF) and dioxane).

[0120] The separation stage via solidification is preferably carried out at a volume ratio of solidification solvent to solidification medium of 1:1 to 10:1, more preferably 2:1 to 5:1. The separation stage via solidification is preferably carried out at a temperature of 5°C to 40°C.

[0121] The stream containing the coagulating solvent (which constitutes an effluent rich in inert compounds) can be recycled, for example, to the resin synthesis step, if a purification step is required beforehand.

[0122] In another preferred arrangement, the separation stage is carried out by liquid-liquid extraction. In this arrangement, the polymer effluent obtained from step c) is washed with a stream mainly containing water. This extraction can be carried out in one or more steps, preferably in one to three steps.

[0123] Liquid-liquid extraction can also be performed upstream of the resin separation process described above, which is carried out by distillation or coagulation.

[0124] In another preferred arrangement, the separation stage is carried out by evaporation, for example by evaporation in a scraped film evaporator.

[0125] The viscosity of a resin-rich effluent depends on its resin content and temperature. Therefore, these contents and temperatures are adjusted to allow the effluent to be conveyed to the drying stage. It is possible to maintain a high temperature to achieve a higher resin content while keeping the effluent at a permissible viscosity, ensuring that the temperature remains below the point of resin thermal degradation.

[0126] The resin-rich effluent is then fed to a drying stage, where it is filtered and then dried. At the end of the drying step, the residual content of inert compounds in the dried resin is less than 3% by weight, preferably less than 1.5% by weight, and more preferably less than 0.8% by weight, relative to the weight of the resin. The residual content of monomers in the dried resin is less than 5% by weight, preferably less than 2% by weight, and more preferably less than 1% by weight, relative to the weight of the resin.

[0127] The glass transition temperature (Tg) of the dried resins is in the range of -50°C to 180°C, preferably 0 to 160°C, and more preferably 20°C to 140°C. Their number-average molecular weight (Mn) is less than or equal to 5000 g / mol, preferably less than or equal to 3000 g / mol, and more preferably less than 1500 g / mol. Their centrifugally average molecular weight (Mz) is less than or equal to 10000 g / mol, preferably less than or equal to 8000 g / mol, and more preferably less than 6000 g / mol.

[0128] The glass transition temperature Tg is measured in a known manner by differential calorimetry or DSC (differential scanning calorimetry), for example, according to the 2014 standard ISO 11357-2 unless otherwise specified.

[0129] The dispersion index (PDI) of the dried resin is less than 3, preferably less than 2.5, and more preferably less than 2.

[0130] Macroscopic structures (weight-average molecular weight, number-average molecular weight, centrifugally average molecular weight, and polydispersity index, denoted as Mw, Mn, Mz, and PDI, respectively) are determined by size exclusion chromatography (SEC) as described below. Mz reflects the thermodynamic equilibrium between deposition and diffusion and depends on the molecular size. This higher order of magnitude average is used as an indicator of the presence of a high molecular weight fraction in the sample.

[0131] It should be noted that SEC analysis, for example, involves separating macromolecules in solution based on their size using a column filled with a porous gel; molecules are separated according to their hydrodynamic volume, with larger molecules eluting first. The sample to be analyzed is pre-dissolved simply in a suitable solvent (tetrahydrofuran) at a concentration of 1 g / L. The solution is then filtered through a filter with a porosity of 0.45 μm and injected into the apparatus at a flow rate of 1 ml / min at 35°C. The equipment used is, for example, the "Waters Alliance" chromatography series.

[0132] Molar calibration was performed using a series of commercially available polystyrene standards with low PDI (below 1.2) and known molecular weights covering the range of molecular weights to be analyzed. Mw, Mn, and PDI = Mw / Mn were obtained from the recorded data (molecular weight distribution curves).

[0133] Therefore, all molecular weight values ​​given in this application are related to calibration curves obtained using polystyrene standards.

[0134] Then, depending on the subsequent use of the resin, the dried resin can be shaped using any method known to those skilled in the art. This shaping can be performed, for example, by granulation.

[0135] The method according to the invention enables the controlled synthesis of hydrocarbon-containing resins using specific conditions of the pyrolysis and separation of the pyrolysis oil, thereby optimizing the recovery of compounds of interest from rubber scraps while limiting substances that may be harmful to the synthesis steps. In this way, resins with excellent properties can be obtained from the recovered products, thus reducing the environmental impact of products using these resins. Attached Figure Description

[0136] [ Figure 1 ] Figure 1 A schematic diagram of the method according to the present invention is shown.

[0137] The feed comprising rubber scrap (1) is fed to the step (A) of pyrolyzing rubber scrap, thereby producing a gas effluent (3), pyrolysis oil (2), and a solid effluent (4). The pyrolysis oil (2) is fed to the step of separating the pyrolysis oil (2) into at least one residue (7), an intermediate fraction (5), and an extract (6), said intermediate fraction (5) containing at least 20% by weight of C4-C. 12Olefin monomers and up to 10% by weight of heteroatoms. The middle fraction (5) is then fed to a resin synthesis step (C), which includes a polymerization stage (preferably operated in the presence of an acid catalyst) with at least the middle fraction (5) supplied, followed by a completion stage to produce a polymer effluent (9). The polymer effluent (9) is treated in a processing step (D), which includes a stage for separating an effluent (11) rich in inert compounds and a resin-rich effluent (15), and a drying stage with the resin-rich effluent (15) supplied to produce a hydrocarbon-containing resin stream (10).

[0138] [ Figure 2 ] Figure 2 A schematic diagram of the method according to the present invention is shown. Figure 1 Common elements have the same tag.

[0139] The feed comprising rubber scrap (1) is fed to the step (A) of pyrolyzing rubber scrap, thereby producing a gas effluent (3), pyrolysis oil (2), and a solid effluent (4). The pyrolysis oil (2) is fed to the step (B) of separating the pyrolysis oil (2) into at least one residue (7), an intermediate fraction (5), and an extract (6), said intermediate fraction (5) containing at least 20% by weight of C4-C. 12 Olefin monomers and up to 10% by weight of heteroatoms. The middle fraction (5) is purified in an optional purification step (P1) and then fed to a resin synthesis step (C), which includes a polymerization stage (C1) operated in the presence of an acid catalyst to produce a stream (12) from the polymerization stage, which is then fed to a completion stage (C2) to produce a polymer effluent (9). A stream (13) containing a terminator compound is also supplied to the completion stage (C2), producing an effluent (14) mainly containing the terminator compound. The polymer effluent (9) is treated in a processing step (D), in which the polymer effluent (9) is fed to a stage (D1) for separating a solvent-rich effluent (11) and a resin-rich effluent (15), and the resin-rich effluent (15) is fed to a drying stage (D2) to produce a hydrocarbon-containing resin stream (10). The solvent-rich effluent (11) can be supplied to an optional purification process (P2) for reuse in the method according to the invention. Detailed Implementation

[0140] Example

[0141] An embodiment of the method according to the present invention is described below.

[0142] pyrolysis steps

[0143] The pyrolysis rubber scrap is supplied with an average diameter of approximately 1 mm and a density of 504 kg / m³. 3 The scrap material is produced by grinding various sizes of heavy-duty truck tires from many brands. This scrap material contains 65% by weight of isoprene elastomer.

[0144] The pyrolysis step is carried out in a reactor under an inert nitrogen atmosphere, which includes three stages operating at temperatures of 425°C, 550°C and 775°C respectively, and thus has a temperature rise profile.

[0145] At the reactor outlet, gaseous effluent, pyrolysis oil, and liquid effluent were separated with the following yields (effluent flow rate / feed flow rate): 13.5%, 44.5%, and 42%, respectively. The pyrolysis oil contained approximately 4% by weight of various monomers of interest, including styrene, methylstyrene, indene, β-pinene, and limonene.

[0146] Steps for separating pyrolysis oil

[0147] The pyrolysis oil is fed to a two-stage distillation separation step at atmospheric pressure. In the first stage, a light fraction with an initial boiling point below 160°C is separated, which constitutes the extract. The heavier fraction is fed to a second stage to produce a residue and an intermediate fraction, the residue having a fractionation point of 280°C, i.e., an initial boiling point of 280°C at atmospheric pressure, which constitutes the intermediate fraction. This fraction contains approximately 33% by weight of olefin monomers, comprising 24.3% by weight of limonene, 2.8% by weight of styrene, and 3% by weight of indene. The intermediate fraction contains 65% by weight of inert compounds. These inert compounds include linear aliphatic and cyclic aliphatic compounds (e.g., 1,2-dimethylcyclopropane, trimethylpentane), monoaromatic compounds (e.g., benzene, toluene, ethylbenzene, xylene), and polyaromatic compounds (e.g., naphthalene and substituted derivatives, anthracene and substituted derivatives and isomers (phenanthrene), phenylnaphthalene and substituted derivatives, pyrene). In inert compounds, the ratio of aliphatic compounds to aromatic compounds is approximately 1:2.

[0148] Resin synthesis steps

[0149] The middle fraction is fed to the resin synthesis step. Aluminum chloride (2 mol% relative to the monomer content) is introduced into the reactor under an inert atmosphere. The reactor is then maintained under an inert atmosphere throughout the reaction.

[0150] The middle fraction was then injected into the reactor. The mixture was stirred at 25°C for 2 hours. The reaction was then stopped by adding water.

[0151] The reaction mixture constituting the polymerization effluent was separated into an inert compound-rich effluent and a resin-rich effluent by washing with water and coagulating the resin with methanol. The resin-rich effluent was then dried in an oven at 175°C for 24 h. The resin was recovered as a yellow / orange translucent solid with a number-average molecular weight Mn = 720 g / mol, a polydispersity index (PDI) of 1.4, and a glass transition temperature (Tg) of 50°C.

Claims

1. Process for the preparation of a hydrocarbon-containing resin starting from a feed comprising rubber crumbs, said process comprising at least: a. a step of pyrolyzing the rubber crumb at a temperature between 300 °C and 900 °C at a temperature ramp, which produces a gaseous effluent, a pyrolysis oil and a solid effluent, the pyrolysis oil comprising at least 1.5 wt% of C4-C 12 olefin monomers; b. a step of separating the pyrolysis oil into at least one raffinate, a middle distillate and an extract, the middle distillate comprising 10 to 90 wt% of C4-C 12 olefin monomers and up to 10 wt% of heteroatoms; c. a resin synthesis step comprising: at least a polymerization phase supplied with the intermediate fraction coming from step b), followed by a finishing phase which produces a polymerization effluent; d. a step of treating the polymerization effluent coming from step c) comprising: a phase for separating an effluent rich in inert compounds and an effluent rich in resin, and a drying phase supplied with the effluent rich in resin which produces a hydrocarbon-containing resin stream; no inert compounds are supplied to the process for the preparation of a hydrocarbon-containing resin, by inert compounds it is understood which are not introduced into the resin in the resin synthesis step c) and which do not interact with the catalytic system.

2. The method of claim 1, wherein, said rubber crumbs have a maximum length in the range of 1 to 100 mm.

3. The method according to any of the preceding claims, wherein, said rubber crumbs comprise at least 50 phr of diene elastomer.

4. The method of claim 1, wherein, the diene elastomer is selected from natural rubber, synthetic polyisoprene, polybutadiene, butadiene copolymers, isoprene copolymers and mixtures of these elastomers.

5. The method of claim 1, wherein, the pyrolysis step comprises a pyrolysis reactor operating at a temperature between 350 and 800 °C, at a pressure lower than 1 bar and with a ratio between the residence time of the solids and the residence time of the gases comprised between 10 and 240.

6. The method of claim 1, wherein, the pyrolysis step is carried out at a temperature increase rate between 1 and 10 °C / min.

7. The method of claim 1, wherein, the intermediate fraction coming from step b) comprises at most 2% by weight of sulfur content.

8. The method of claim 1, wherein, the separation step b) is carried out by distillation.

9. The method of claim 8, wherein, the separation step b) is carried out in a column having internal walls, the intermediate fraction being obtained by withdrawing a side stream from said column.

10. The method of claim 1, wherein, the intermediate fraction coming from step b) is subjected to a purification treatment before being supplied to step c).

11. The method of claim 10, wherein, the content of heteroatoms in the intermediate fraction at the end of the purification treatment is lower than 2% by weight.

12. The method of claim 1, wherein, the polymerization phase is operated in the presence of an acid catalyst.

13. The method of claim 1, wherein, the finishing phase of step c) is carried out by contacting at a temperature between 5 and 80 °C with a stream comprising a terminator compound selected from water, C1-C3 alcohols and mixtures thereof, then separating the polymerization effluent and an effluent mainly comprising the terminator compound by phase decantation.

14. Rubber finished or semi-finished product comprising a resin obtained by the process according to any one of the preceding claims.

15. Pneumatic or non-pneumatic tire comprising a resin obtained by the process according to any one of claims 1 to 13.

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