Method for preparing at least one aromatic monomer from a product comprising a polyester

Abstract

The invention relates to a method of preparation of at least one monomer (MArx) from a product (P), wherein said monomer is selected in the group consisting of dihydroxybiphenyl (MAr1), 6-hydroxy 2-naphthoic acid (MAr2) and 4-hydroxybenzoic acid (MAr3) and / or a combination of (MAr2) with (MAr3) and wherein product (P) comprises at least one polyester (PE) and is based on a sequence of precipitations.

Description

1 SSPU 2024 / 044-WO-PCTMethod for preparing at least one aromatic monomer from a product comprising a polyesterThis application claims priority of US provisional application N°63 / 739,418 filed on 27 December 2024 and European patent application N°25152738.8 filed on 20 January 2025, the content of which being entirely incorporated herein by reference for all purposes. In case of any incoherency between this application and one of the priority applications that would affect the clarity of a term or expression, it should be made reference to this application only.

[0001] The present disclosure relates to a method for preparing at least one aromatic monomer or a Derivative thereof from a product comprising at least one polyester. The method is adapted to the recovery of at least one aromatic monomer from a waste, notably an electronic material, comprising said polyester.[Context of the invention]

[0002] Plastics are inexpensive and durable materials, which can be used to manufacture a variety of products that find use in a wide range of applications, so that the production of plastics has increased dramatically over the years since their discovery. It is estimated that about 40% of these plastics are used for single-use disposable applications, such as packaging, agricultural films, disposable consumer items or for short-lived products that are discarded within a year of manufacture. Because of the durability of the polymers involved, substantial quantities of plastics are piling up in landfill sites and in natural habitats worldwide, generating increasing environmental problems. Even degradable and biodegradable plastics may persist for decades depending on local environmental factors, like levels of ultraviolet light exposure, temperature, presence of suitable microorganisms, etc.

[0003] Liquid crystalline aromatic polyesters (LCPs) are a very important class of engineering polymer. Their low melt viscosities combined with their excellent mechanical properties make them extremely useful for the fabrication of intricate constructs for numerous optical and electronic devices.

[0004] One solution to reduce environmental and economic impacts correlated to the accumulation of plastic is closed-loop recycling wherein plastic material is mechanically reprocessed to manufacture new products. For example, one of the most common closed-loop recycling is the polyethylene terephthalate (PET) recycling. PET wastes are subjected to successive treatments leading to a food-2 SSPU 2024 / 044-WO-PCTcontact-approved recycled PET, which is collected, sorted, pressed into bales, crushed, washed, chopped into flakes, melted and extruded in pellets and offered for sale. Then, these recycled PET may be used to create fabrics for the clothing industry or new packaging such as bottles or blister packs, etc.

[0005] Mechanic recycling is not always possible to deliver the identical level of performances as the virgin materials. Sometimes it is thus necessary to depolymerize down the waste to recover the monomers and rebuild a fresh polymer from them. This is especially required for compound where all the additives and fillers added to reach the targeted level of performance are damaged due to the use and ageing of the material, and need to be removed.[Background art!

[0006] CN 103664513 (D1) discloses a method for hydrolyzing and recovering monomers of an aromatic polyester composite material characterized in that it comprises the following steps: mixing and reacting the aromatic polyester composite material with an aqueous caustic soda solution and a polar solvent to obtain a decomposition liquid of the aromatic polyester and then separating biphenol, terephthalic acid and p-hydroxybenzoic acid from the decomposition liquid. There is no disclosure of a product (P) containing at least two aromatic polyesters. Moreover, D1 does not disclose the preparation of Purified p-hydroxybenzoic acid (MAF3). Finally, the process of D1 is based on the use of a significant quantity of a polar solvent with proportion p > 70 wt%.

[0007] US 2023 / 192982 discloses a method of depolymerizing a polyester in a waste material.

[0008] WO 2024 / 053927 discloses a method for producing terephthalic acid in an eco- friendly manner using waste polyester.

[0009] US 4,542,239 discloses a method for recovering terephthalic acid from PET, which method comprises decomposing the waste PET under pressure in an ammonium hydroxide medium, and then acidifying the resulting aqueous solution of diammonium terephthalate to obtain a terephthalic acid precipitate.

[0010] US 6,723,873 discloses a method for recovering terephthalic acid from PET through aminolysis, wherein PET polyester is reacted with ammonium hydroxide to produce diammonium terephthalate, and diammonium terephthalate is converted into terephthalic acid at 225°C ~ 300°C. Other known methods for depolymerization of polyesters include high temperature thermal decomposition and acid decomposition. The thermal decomposition method produces a lot of tarry3 SSPU 2024 / 044-WO-PCTby-products with complex components. The acids used include hydrochloric acid and organic acids.

[0011] CN 1272103 describes a method for recovering 2,6-naphthalenedicarboxylic acid by decomposing polyester in the presence of an organic acid.

[0012] Sueoka, K. , et al. , “Compositional analysis of liquid crystalline aromatic polyesters” Anal. Sci., 1990, 6(3): p. 371-4 (DOI:10.2116 / ANALSCI.6.371) discloses the hydrolysis under basic conditions of four aromatic polyesters. See also: Polymers 2011, 3, 367-387; doi:10.3390 / polym3010367 “Structural Analysis of Aromatic Liquid Crystalline Polyesters”.

[0013] KR 2020 / 0129882 discloses a separation method for recycling a liquid crystal polymer through the separation of a liquid crystal polymer from other polymer resins via a multistage method.

[0014] WO 2004 / 016673 relates to Liquid Crystalline Polyesters (LCP) and discloses some specific LCPs.

[0015] US 2023 / 0257519 discloses LCPs and the various monomers usually used in their preparation.

[0016] US 2024 / 0067594 discloses the recovery of monomers from a waste material.

[0017] None of these documents discloses or suggests the method of the invention.[Technical problem to be solved!

[0018] The amount of waste electrical and electronic equipment generated every year is increasing rapidly. It is now one of the fastest growing waste streams. It includes a large range of devices such as mobile phones and computers. E-waste contains a complex mixture of materials, some of which are hazardous. These can cause major environmental and health problems if the discarded devices are not managed properly. Modern electronics also contain rare and expensive resources, including critical raw materials. These can be recycled and re-used if the waste is effectively managed.

[0019] Improving the collection, treatment and recycling of electrical and electronic equipment at the end of their life can increase resource efficiency and support the shift to a circular economy. It can also contribute to the security of supply for critical raw materials, ultimately enhancing the EU’s strategic autonomy.

[0020] There is a need for an efficient and easy method to recover the aromatic monomers from a product containing a polyester, such as a LCP (Liquid Crystalline Polymer), notably from electronic components containing said LCP, such as connectors widely used on integrated circuit contained in computers, mobile electronic devices and automobiles, lighting and sensors in automotive, 5G antennas, LCP films from4 SSPU 2024 / 044-WO-PCTLC Display and flexible printed circuit board (see https: / / www.samaterials.com / content / liquid-crystal-polymer-lcp-films-in-the- electronics-industry.html).

[0021] The method of the invention aims at solving this technical problem.[Brief disclosure of the invention!

[0022] The method of the invention is disclosed in any one of the claims 1-24.

[0023] More precisions and details about the method are now provided below.[General definitions!

[0024] wt.% is a percentage by weight. Mol.% is a percentage by mole.

[0025] When numerical ranges are given herein, unless otherwise expressly indicated, the end-points of the ranges (even in the open-ended ranges such as those comprising "at least", "at most", "lower than", "up to", etc or in ranges comprising “between") are included. The expression "at least" therefore corresponds to the mathematical symbol > in the context of the present invention. The expression "at most" or "up to"therefore corresponds to the mathematical symbol < in the context of the present invention. For clarity then, the ranges comprising the expressions “between X and Y” are thus equivalent to “from X to Y”.

[0026] An acid is a chemical compound that dissociates in water to produce positive hydrogen ions.

[0027] A base is a chemical compound that can accept hydrogen cations (H+) in water.

[0028] An aromatic monomer refers to a monomer comprising at least one aromatic ring in its structure.

[0029] Filtrate designates the liquid medium separated from a suspension of particles present in a liquid medium.

[0030] The proportions of recurring units in a polymer are expressed in mol% and given relative to the total amount of recurring units in said polymer.

[0031] In the present application, unless otherwise indicated, any specific embodiment or technical feature relating to the method of the invention is applicable to and interchangeable with another embodiment or technical feature also relating to the method of the invention and disclosed elsewhere in the application.

[0032] The expression "Purified " designates a molecule, in particular a monomer, with a purity (p) of at least 95.0%, preferably at least 98.0%, preferably at least 99.0%, preferably at least 99.5%, this purity being determined by a chromatographic technique such as gas chromatography or high-performance liquid chromatography (HPLC).5 SSPU 2024 / 044-WO-PCT

[0033] The term “Derivative" (with capital D) designates a monomer where at least one - OH group is replaced by an ester group of formula -O-C(=O)-R where R is an optionally substituted (Ci-Cis)-hydrocarbyl group, such as an optionally substituted (Ci-Cis)-alkyl group. Such a Derivative is prepared by well-known chemical reactions, e.g. involving an acylating agent.

[0034] The expression "consist essentially of recurring units (X) " in relation to the recurring units of a polyester (PE) means that the recurring units of the polyester (PE) consist of recurring units (X) and up to 6.0 mol. %, preferably up to 5.0 mol%, preferably up to 3.0 mol%, preferably up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of recurring units other than (X). Likewise, the expression "consist essentially of recurring units (X) and (Y)" in relation to the recurring units of a polyester (PE) means that the recurring units of the polyester (PE) consist of recurring units (X) and (Y) and up to 6.0 mol. %, preferably up to 5.0 mol%, preferably up to 3.0 mol%, preferably up to 1.5 mol%, preferably up to 1.0 mol%, preferably up to 0.5 mol%, of recurring units other than (X) and other than (Y).

[0035] As used herein, the terminology “(Cn-Cm)” in reference to an organic group or molecule, wherein n and m are integers indicates that the group or molecule contains from n carbon atoms to m carbon atoms per group, n and m being included.

[0036] An hydrocarbyl group is an univalent group formed by removing a hydrogen atom from a hydrocarbon. An example of hydrocarbyl group is an alkyl group or an aryl group.[Figure!

[0037] Fig. 1 illustrates the method of the invention for a given product comprising at least one polyester (PE) wherein a liquid medium (Lo) comprises the three aromatic monomers MAF1 , MAF2 and MAF3.

[0038] Fig. 2 and Fig. 3 illustrate the method of the invention for a liquid medium (Lo) comprising only two monomers (Mi), such as HNA (MAF2) and HBA (MAF3). in Fig.2, j=2 and in Fig. 3, j=1.

[0039] Fig. 4 illustrates the method of the invention applied in the specific conditions of the examples.[Disclosure of the invention]

[0040] The invention relates to a method of preparation of at least one monomer (MArx) or a Derivative thereof as defined in claim 1.6 SSPU 2024 / 044-WO-PCT

[0041] The method of the invention makes it possible to prepare at least one monomer (MAFX), the method comprising step (a) and optional step (b) as defined below: step (a): a basic aqueous solution is brought into contact with product (P) so as to obtain an aqueous liquid medium (Lo) exhibiting a pH > 7.0 and comprising the constituent monomers (Mi) of the polyester(s) (PE(s)) present in product (P);step (b): the insoluble material(s), notably the GFs (if any), the metallic component(s) (MG) or the plastic additive(s) (Add), that may be present in (Lo) are separated partially or totally;and the method also further comprises after step (a) or (b), one or more recovery steps (q), each step (q) comprising:• a precipitation substep (caj) to obtain a precipitate (PRj) enriched in a constituent monomer (Mj); and• optionally one or more purification substep (cbj) if monomer (Mj) is one of the aromatic monomers (MArx), x being 1, 2 or 3;where:o in step (caj): an acid (Ac) is brought into contact with an aqueous solution (Sj-i) comprising at least two constituent monomers (Mj) in order to decrease the pH of solution (Sj-i) to obtain:■ a precipitate (PRj) comprising one constituent monomer (Mi) in the solid form with a proportion higher than 50.0 wt% (> 50.0 wt%) of monomer (Mi), this proportion being based on the total weight of precipitated constituent monomers (Mi) present in precipitate (PRj); and■ an aqueous solution (Sj), separated from precipitate (PRj): o in step (cbj): the purity (p) of the precipitated monomer (Mj) present in the precipitate (PRj) with the proportion > 50.0 wt% is increased by at least one separation method selected in the group consisting of recrystallization, distillation, washing and extraction, the separation being either performed directly on the monomer (Mj) itself or to a derivative of said monomer, notably a Derivative of said monomer; where the aqueous solution (So) that is used in step (ci) is the basic liquid medium obtained after step (a) or a basic aqueous solution obtained after step (b).

[0042] The method of the invention is based on the use of controlled precipitation steps (caj), where in each precipitation step (caj), the precipitation of each step being induced by a control of the pH. Moreover, generally, in the sequence of7 SSPU 2024 / 044-WO-PCTprecipitation steps, it is observed that the pH of precipitation used in step (caj) noted pHj is such that pHj-i > pHj where pHj-i is the pH of precipitation used in (caj.1) and pH of (So) > pHi of step (cai).

[0043] The method of the invention also makes it possible to prepare at least one Derivative of monomer (MAFX). In this case, the Derivative of the monomer is prepared in a step (d) after step (c) wherein monomer (MArx) is converted into said Derivative after step (c) or is recovered in a step (cbj).

[0044] The monomer(s) or Derivative(s) recovered can be used again in a polymerization reaction, typically a polycondensation.

[0045] In the method of the invention, the following notations are used:i is an integer corresponding to the constituent monomers initially present in the aqueous basic liquid medium (Lo) following the hydrolysis step (a), i is therefore strictly higher than 1 since there are at least two constituent monomers in a polyester (PE). In example 1, i=5 since product (P) is based on the combination of PE1 containing in polymerized form 4 monomers and PE2 containing in polymerized form 2 monomers and PE3 containing in polymerized form 3 monomers, some of these monomers being common among the PEs. Each constituent monomer present is identified as (Mi);among the constituent monomers (Mj) that are present in product (P), one distinguishes the three specific aromatic monomers noted MAFX where x is an integer selected in group {1, 2, 3};- j is an integer higher than or equal to 1 corresponding to the jthstep ( ) used in the method of the invention, being understood that step (q+i) is performed after step (q).

[0046] According to a preferred embodiment, the method is used for a product (P) comprising a sufficient proportion of at least one aromatic monomer(s) (MAFX). This ensures a more economical and more environmental friendly method of recovery. Therefore, the total proportion in (Lo) of aromatic monomer(s) (MAFX) as defined herein is preferably at least 5.0 wt%, preferably at least 10.0 wt%, this proportion being expressed relative to the total amount of constituent monomers (Mi) present in (Lo).

[0047] Monomers prepared (or recovered) by the method of the invention

[0048] The method of the invention makes it possible to prepare at least one monomer (MArx) or a Derivative thereof selected in the group consisting of a dihydroxybiphenyl (MAr1), 6-hydroxy 2-naphthoic acid (MAr2) and hydroxybenzoic acid (MAr3) and isomers thereof.

[0049] A dihydroxybiphenyl (MAF1) is a chemical compound having the following formula:8 SSPU 2024 / 044-WO-PCTwhere each hydroxy group can occupy any one of the 5 positions present on each phenyl ring. (MAF1) is more particularly 4,4’-dihydroxybiphenyl of formula

[0050] 6-hydroxy 2-naphthoic acid is the compound of formula:

[0051] A hydroxy benzoic acid (MAF3) is a chemical compound having the followingformula:the hydroxy group can occupy any one of the 5 positions present on the phenyl ring. (MAF3) is more particularly or preferably 4- hydroxybenzoic acid. 4-hydroxybenzoic acid is the compound of formula:"

[0052] According to an embodiment, the method makes it possible to prepare the following monomer(s):(MAr1); or(MAr2); or(MAr3); or(MAF1) and (MAF2); or(MAF1) and (MAF3); or(MAF2) and (MAF3); or(MAF1) and (MAF2) and (MAF3);being understood that one or more of these monomers may be in the form of a Derivative.9 SSPU 2024 / 044-WO-PCT

[0053] According to an embodiment, the method provides a Purified monomer or Purified Derivative.

[0054] The method of the invention makes it possible to obtain Purified (MAF3) when liquid medium (Lo) comprises (MAF3) as one of the constituent monomers.

[0055] It is mentioned that some specific (MAF2) and (MAF3) are often used in combination for the preparation of certain polyesters having in polymerized form 6-hydroxy 2- naphthoic acid (MAF2) and 4-hydroxybenzoic acid (MAF3) such as Vectra® A950. Therefore, the method of the invention makes it possible also to prepare a composition containing 6-hydroxy 2-naphthoic acid (MAF2) in combination with 4- hydroxybenzoic acid (MAF3) after a step (cbj). As an alternative, the purification substep (cbj) may be avoided for obtaining the composition containing 6-hydroxy 2-naphthoic acid (MAF2) in combination with 4-hydroxybenzoic acid (MAF3) after a step (caj).

[0056] Product (P)

[0057] Product (P) comprises:® at least one polyester (PE) as defined herein;® optionally glass fibers (GF);® optionally at least one metallic component (MG);® optionally at least one plastic additive (Add).

[0058] According to an embodiment, product (P) comprises:® at least one polyester (PE) as defined herein;® glass fibers (GF);® optionally at least one metallic component (MC);® optionally at least one plastic additive (Add).

[0059] According to an embodiment, product (P) comprises:® at least one polyester (PE) as defined herein;® glass fibers (GF);® at least one metallic component (MC);® optionally at least one plastic additive (Add).

[0060] Product (P) may comprise glass fibers (GF) which are typically present blended in one of more polyesters (PEs) present in product (P).

[0061] Product (P) may comprise at least one metallic component (MC). A metallic component (MC) is based on or comprises a metal such as copper or aluminium or an alloy such as brass or steel. A metallic component (MC) is typically present in combination with a polyester in electronic components. Examples of electronic components are described in US 2024 / 0413548.10 SSPU 2024 / 044-WO-PCT

[0062] Product (P) may comprise at least one polymer additive (Add) typically present blended in one of more polyesters (PEs) present in product (P). The polymer additive (Add) is generally selected in the group consisting of fillers other than GFs, colorants, dyes, pigments, lubricants, plasticizers, flame retardants, nucleating agents, heat stabilizers, UV stabilizers, elastomers, core-shell particles, adhesives, antioxidants and processing aids. The polymer additive (Add) may more particularly be selected in the group consisting of fillers other than GFs, colorants, dyes, pigments, lubricants, elastomers and heat stabilizers. A filler other than GFs is typically talc.

[0063] At least one polyester (PE) present in product (P) comprises recurring units derived from at least one aromatic monomer (MAFX) selected in the group consisting of dihydroxybiphenyl (MAF1) and any isomer thereof, 6-hydroxy 2-naphthoic acid (MAF2) and 4-hydroxybenzoic acid (MAF3).

[0064] According to an embodiment (E1), product (P) comprises only one polyester (PE).

[0065] According to a preferred embodiment (E2), product (P) comprises at least two polyesters (PEs). This embodiment covers the possibilities of (i) at least two polyesters (PEs) being of a different chemical composition and also (ii) at least two polyesters (PEs) of the same chemical composition and differing by at least one physicochemical property.

[0066] The method of the invention is adapted to the recovery of at least one monomer (MAFX) from a waste material comprising at least one polyester (PE).

[0067] The proportion of polyester(s) (PE(s)) in product (P) is generally at least 10.0 wt.%, this proportion being based on the total weight of product (P). This proportion may more particularly be at least 15.0 wt, more particularly at least 20.0 wt, more particularly at least 50.0 wt%. This proportion may be 100 wt.% if product (P) consists of polyester(s) (PE(s)). Yet, this situation is rare as polyesters are generally present in combination with other materials, notably in electronic wastes. The proportion of polyester(s) (PE(s)) in product (P) is generally less than 99.9 wt.%, more particularly less than 99.5 wt.%.

[0068] About polyester (PE)

[0069] Product (P) comprises at least one polyester (PE).

[0070] Polyester (PE) comprises at least 80.0 mol% of recurring units (RPE) selected in the group consisting of recurring units (RAr) of formula [-(Xi)-Ar-(X2)-] and recurring units (RCy) of formula [-C(=O)-Cy-C(=O)-] where:- Xi and X2are independently selected in the group of -O- and -C(=O)-;- Ar is selected from the group of phenylene, biphenylene and naphtylene groups;11 SSPU 2024 / 044-WO-PCT- Cy designate a cyclohexylene group, notably 1,3- and / or 1 ,4-cyclohexylene group.

[0071] According to an embodiment, polyester (PE) is selected in the group of aromatic polyesters, semi-aromatic polyesters and polyesteramides.

[0072] The recurring units (RPE) of an aromatic polyester consist of or consist essentially of recurring units (RAF). These recurring units are typically bonded to one another by ester bonds.

[0073] The recurring units (RPE) of a semi-aromatic polyester consist of or consist essentially of recurring units (RAF) and (Rcy). These recurring units are typically bonded to one another by ester bonds.

[0074] The recurring units (RPE) of a polyesteramide consist of or consist essentially of recurring units (RAF), (Rcy) and (RAm) where (RAm) ar of formula:where the -NH- group is positionned in meta or para position relative to the -O- group. The proportion of (RAm) in the polyesteramide is typically at most 10.0 mol%. These recurring units are typically bonded to one another by ester or amide bonds.

[0075] Polyester (PE) is prepared by polycondensation. Polycondensation typically involves the formation of ester bonds and also amide bonds when monomer (Am) is also present in the reaction mixture. The condensation of said monomers typically occurs at a temperature of at least 200°C.

[0076] Recurring units (RPE) are obtained from monomers selected in the group of monomers (ArM) of formula HXi-Ar-X2H, monomer (CyM) of formula HOC(=O)-Cy-C(=O)OH, monomer of formula (Am) of formula: where the -NH2group is positionned in meta or para position relative to the -OH group.

[0077] The monomers typically encountered in polyester (PE) are the following ones: 1) hydroxyacids (Xi=OH, X2=COOH): 3-hydroxybenzoic acid (MAF3), 4- hydroxybenzoic acid (MAF3); 6-hydroxy-2-naphthoic acid (MAF2); 2) dicarboxylic acids (XI=X2=COOH): terephthalic acid, isophthalic acid, 2,6- naphthalenedicarboxylic acid; 3) diols (Xi=OH, X2=OH): 4,4’-biphenol (MAF1), 3,4’- biphenol (MAF1), 3,3’-biphenol (MAF1), hydroquinone (HQ), methyl-hydroquinone,12 SSPU 2024 / 044-WO-PCTtert-butylhydroquinone, 4,4’-isopropyilidenediphenol; 4) amino-ols: acetaminophen. For the preparation of a polyester, the monomers listed may also be in the form of a Derivative with R being a C2-Cs-alkyl group.

[0078] Examples of polyesters (PE) often also denoted LCP (Liquid Crystalline Polymers) are now provided in column 1 or column 2 of the table below:BP: dihydroxybiphenyl; HBA: 4-hydroxybenzoic acid; HNA: 6-hydroxy 2-naphthoate; T: terephthalic acid; I: isophthalic acid; BB: bibenzoic acid; HQ: hydroquinone

[0079] (ArM) is typically selected in the group consisting of 4,4-dihydroxybiphenyl (MAFI), 6-hydroxy 2-naphthoic acid (MAF2), 4-hydroxybenzoic acid (MAF3), hydroquinone, terephthalic acid and isophthalic acid.

[0080] Optional pretreatment of product (P) before step (a)

[0081] Product (P) may be pretreated prior to step (a). The pretreatment step may include a mechanical or physical modification of product (P), such as a reduction of its size by a suitable method such, but not limited to shredding, cutting, crushing or grinding.

[0082] Product (P) is conveniently in the form of particles with a size lower than 10.0 mm, preferably lower than 5.0 mm, even preferably lower than 3.0 mm.13 SSPU 2024 / 044-WO-PCT

[0083] Product (P) may also be pretreated prior to step (a) by a treatment to remove impurities and dirt

[0084] Step (a)

[0085] In step (a), the polyester(s) (PE(s)) are depolymerized into the constituent monomers (Mi) of said polyester(s). In the present disclosure, the term “constituent monomer” is used irrespective of the fact that the chemical groups of the constituent monomer are in the neutral form (-COOH, -OH or -NH2) or in the salt form (-COO-, -O', -NH3+). In other words, the chemical groups of the constituent monomers (Mi) that are present in the liquid medium (Lo), in a aqueous solution (Sj) or in a precipitate (PRj) are totally or partly in the neutral form (-COOH, -OH or -NH2) or in the salified form (-COO', -O', -NH3+).

[0086] In step (a), a basic aqueous solution is brought into contact with product (P) so as to obtain an aqueous liquid medium (Lo) exhibiting a pH > 7.0 and comprising the constituent monomers (Mj) of the polyester(s) (PE(s)) present in product (P).

[0087] Each constituent monomer (Mj) is either dissolved or present in the solid form in the aqueous liquid medium (Lo). Each monomer may also be partly dissolved and partly in the solid form. This depends inter alia on the chemical structure of the monomer, the proportion of said monomer in (Lo), the temperature of (Lo) and the pH of (Lo).

[0088] According to an embodiment, the aqueous liquid medium (Lo) comprises also insoluble material(s). The insoluble materials are notably the GFs (if any), the metallic component(s) (MG) (if any), some of the additive(s) (Add) (if any). The insoluble materials may also be the unreacted or partially hydrolyzed polyester(s) and / or the products of degradation of the components of product (P).

[0089] Step (a) is generally performed in a vessel. The order of addition of the components introduced into the vessel is not important. For instance, the order of addition of the components may be the following: water, product (P), then at least one base; or: product (P), water, then at least one base; or the following: product (P), at least one base, then water, being understood that the at least one base may be added in the form of an aqueous basic solution.

[0090] The base is selected in the group consisting of NaOH, KOH, Na2COs, K2CO3, tertiary amines (e.g. triethylamine), pyridine and combination thereof. The base of the aqueous basic solution is preferably NaOH or KOH.

[0091] At the end of step (a), the pH of the aqueous basic liquid medium (Lo) is preferably at least 11.0, preferably at least 12.0, preferably at least 13.0.

[0092] According to an embodiment, the pH of (So) is preferably at least 11.0, preferably at least 12.0, preferably at least 13.0.14 SSPU 2024 / 044-WO-PCT

[0093] Step (a) is typically performed at a temperature which is at least 50°C, preferably at least 80°C.

[0094] According to an embodiment, the reaction mixture (RM) of step (a) comprising water, product (P) and at least one base is free of polar solvent (S) selected in the group consisting of methanol, tetrahydrofuran, 1,4-dioxane, N,N- dimethylformamide and combination thereof.

[0095] According to an embodiment, the reaction mixture (RM) of step (a) comprising water, product (P) and at least one base is free of an organic solvent, more particularly free of an organic solvent selected in the group consisting of alcohols, cyclic ethers and solvents containing amide bonds. For the sake of clarity, the monomers of polyester(s) (PE(s)) are not considered as organic solvents.

[0096] For both of these two embodiments, the expression "free of" means in association with the solvent that the proportion p of a solvent in the reaction mixture (RM) is lower than or equal to 50.0 wt% (< 50.0 wt%), preferably lower than or equal to 25.0 wt% (< 25.0 wt%), preferably lower than or equal to 10.0 wt% (< 10.0 wt%), preferably lower than or equal to 5.0 wt% (< 5.0 wt%), preferably lower than or equal to 1.0 wt% (< 1.0 wt%), this proportion of solvent being calculated by the following equation:p (wt%) = proportion by weight of solvent in RM / [proportion by weight of solvent in RM + proportion by weight of water in RM] x 100.

[0097] A lower proportion of polar solvent ensures that the method of the invention is safer and may also eliminate the need of further step(s) of distilling off or eliminating the solvent initially added.

[0098] The proportion of the base(s) of the aqueous basic solution which is used in step (a) is such that the hydrolysis of the polyester(s) is substantially complete. This proportion is preferably such that molar ratio [base(s) / total amount of ester bonds from the polyester(s) (PE(s))] is from 1.1 to 10.0, preferably from 1.5 to 6.0, more preferably from 2.0 to 4.0, and even more preferably from 2.0 to 3.0.

[0099] The conditions used for step (a), notably the duration of step (a), are preferably such that the degree of conversion R of the PE(s) into the constitutive monomers (Mi) is high enough. The duration of step (a) depends on the temperature used in step (a), the size of the particles of product (P) and the pH of the reaction medium. The duration of step (a) is typically between 2.0 and 24.0 hours.

[0100] Degree of conversion R: the degree of conversion of polyester(s) (PE(s)) R achieved at the end of step (a) is preferably at least 90.0 wt %, preferably at least 93.0 wt % more preferably at least 95.0 wt %. The degree of conversion is calculated by mass balance. An example of calculation is given in example 2.15 SSPU 2024 / 044-WO-PCT

[0101] Optional step (b)

[0102] In step (b), the insoluble material(s), notably the GFs (if any), the metallic component(s) (MC) (if any) or the additive(s) (Add) (if any), that may be present in (Lo) are separated partly or totally.

[0103] The separation is typically performed by at least one filtration step.

[0104] As after step (a), some of the monomers may be partly in the solid form, it is preferable to dissolve them in the aqueous liquid medium before performing the separation to ensure that the yield of recovery is kept high. Dissolution may be performed by heating up the solution or by diluting the aqueous liquid medium with added water.

[0105] Step

[0106] The method of the invention comprises one or more steps (Cj), each step ( ) comprising a precipitation substep (caj) to obtain a precipitate (PRj) enriched in constituent monomer (Mi).

[0107] In each precipitation step (caj), an acid (Ac) is brought into contact with an aqueous solution (Sj-i) comprising the constituent monomers (Mj) in order to decrease the pH of the aqueous solution (Sj_i) and obtain:■ a precipitate (PRj) comprising a proportion (PROj) of a constituent monomer (Mj) in the solid form higher than 50.0 wt% (> 50.0 wt%), this proportion being based on the total weight of the precipitated constituent monomers (Mi) present in precipitate (PRj); and■ an aqueous solution (Sj), separated from precipitate (PRj).PROj is thus calculated by the following formula:

[0108] In the precipitation step, acid (Ac) is preferably added to the stirred aqueous solution (Sj-i) to decrease its pH. This makes it possible to better control the decrease of the pH of the aqueous solution.

[0109] The addition of the acid (Ac) to the stirred solution (Sj_-i) is also preferably added at a controlled rate to control the decrease of the pH of the aqueous solution. The addition of the acid (Ac) to the stirred aqueous solution (Sj_-i) can be performed continuously or portion-wise.

[0110] The acid (Ac) is typically in the form of an aqueous acidic solution.

[0111] Acid (Ac) is preferably selected from the group of HCI, H2SO4 and combination thereof.16 SSPU 2024 / 044-WO-PCT

[0112] The quantity of acid (Ac) added is such that the precipitate (PRj) comprises monomer (Mj) with a proportion (PROj) higher than 50.0 wt% (> 50.0 wt%), this proportion being based on the total weight of the precipitated constituent monomers present in the precipitate (PRj). For one or more step (caj), (PROj) is preferably greater than or equal to 60.0 wt% (> 60.0 wt%), preferably greater than or equal to 70.0 wt% (> 70.0 wt%), preferably greater than or equal to 80.0 wt% (> 80.0 wt%). The higher (PROj), the better the efficiency of each step ( ) and the easier the purification step (cbj).

[0113] The quantity of acid (Ac) needed to trigger the precipitation depends on the range of pH at which a monomer precipitates. This range depends, on the one hand, on the chemical structure of said monomer and, on the other hand, on other parameters such as the temperature of the solution, the other components of and their proportions in the aqueous solution (Sj-i).

[0114] Known ranges are given for some monomers:

[0115] The yield (Yj) of recovery of monomer (Mi) in precipitate (PRj) is preferably higher than 50.0 wt% (> 50.0 wt%), this yield being expressed in % and calculated by the following formula:For clarity, the weight of monomer (Mi) taken into account for this calculation is the weight of the precipitated monomer alone not taking into account other products that may be associated with the precipitated monomer (Mi) such as water or other residues.

[0116] The example below illustrates the influence of pH on PROj and Yj. Product (P) is based on Vectra® A950, which is a polyester (PE) having in polymerized form HNA17 SSPU 2024 / 044-WO-PCT(MAr2) and HBA (MAr3) [HNA (27 mol%) / HBA (73 mol%)]. After hydrolysis of the polyester with NaOH, the liquid medium (Lo) comprises said two monomers and i=2. Acid (HCI) is added gradually to stirred (Lo). The pH of equilibrium influences (PROj) and (Yj):As can be seen, at pH=5.5, the proportion of HNA and the yield of HNA are both high.

[0117] The optimization of parameters PROj and Yj can be performed in the following way:for each solution (Sj-i), the pH is decreased slowly (by slow stepwise addition of acid) until it reaches a given pH of equilibrium and parameters PROj and Yj are measured. It is therefore possible for each solution (Sj-i) to draw the curves PROj vs pH and Yj vs pH and to determine the range of pH where both parameters are high or optimized.

[0118] The number of steps ( ) generally depends on the number of constituent monomers (Mi) present in the liquid medium (Lo). In the simplest case, liquid medium (Lo) comprises only two monomers (Mi), such as HNA (MAr2) and HBA (MAr3). The recovery of both purified monomers could then be based on the method illustrated in Fig. 2 which comprises two steps (c1) with substeps (cal) and (cb1) and (c2) with substeps (ca2) and (cb2). If only purified (MAr2) is needed, the method can be based on the method illustrated in Fig. 3 which comprises two steps (c1) with substeps (cal) and (cb1) and (c2) with only one substep (ca2).

[0119] j designates the number of recovery steps (cj). j typically increases with the number of constituent monomers (Mj) present in the liquid medium (Lo). According to an embodiment, j < i. This embodiment is followed when not all constituent monomers are purified. According to another embodiment, j > i. This embodiment is followed when a constituent monomer (Mj) is recovered in multiple steps ( ) to increase the overall yield of recovery of said monomer. This is possible if a first recovery step ( ) leads to a first fraction enriched in (Mi) and a second fraction to recover an additional proportion of (Mj).

[0120] For j > 2, the method thus involves a sequence of steps ( ) (and precipitation steps (caj). For a liquid medium (Lo) comprising all three monomers (MArx), the18 SSPU 2024 / 044-WO-PCTprecipitation steps are sequenced in this order: precipitation of: precipitation of (MAF1) => precipitation of (MAF2) => precipitation of (MAF3).

[0121] Step (cbi)

[0122] Step (cbj) is performed if the constituent monomer (Mj) is one of monomers (MArx) to be purified.

[0123] In this step (cbj), the purity (p) of precipitated monomer (Mj) present in the precipitate (PRj) with the proportion > 50.0 wt% is increased by at least one separation method selected in the group consisting of recrystallization, distillation, washing and extraction.

[0124] The separation may be either performed directly on the monomer itself or to a derivative of said monomer, notably a Derivative of said monomer.

[0125] Separation performed on a derivative of a constituent monomer (Mi): the monomer is (i) first chemically converted into a derivative, notably a Derivative, by one or more chemical reactions, then (ii) the purity of the derivative is increased by at least one separation method selected in the group consisting of recrystallization, distillation, washing and extraction. After (ii), the derivative may be chemically converted back to the monomer by one or more chemical reactions or if the derivative is a Derivative, one can recover the Derivative.

[0126] For example, BP can be converted into diester (Derivative). This sequence is particularly well adapted to monomers (MArx) through the use of a diester with R= (Ci-Cs)-alkyl. As an example, (MAF1) can be purified by distillation of its diacetate. The sequence is then the following (i) 4,4'-dihydroxybiphenylconversion into diacetate (R=Me) with the use of the anhydride of acetic acid(ii) distillation of the diacetatepurified diacetate(iii) conversion into 4,4'-dihydroxybiphenyl form to ease up its purification by distillation. The purified diacetate may also be used directly as a monomer in a polycondensation if it can react in this chemical state.[Experimental section!

[0127] The overall scheme illustrating these examples is present on Fig. 4 [on Fig. 4, PTA:terephthalic acid; IPA: isophthalic acid],

[0128] Example 1 - preparation of a product (P) comprising three polyesters PEs and GFs

[0129] A product (P) is prepared by combining in the solid form the PEs disclosed in Table I.19 SSPU 2024 / 044-WO-PCTTable IIn this table, the proportions are given for the aromatic monomers (under the repeat unit form) present in the polyesters.

[0130] Composition of product (P) is thus equivalent to the following composition expressed in wt%:• 57 wt.% of 4-hydroxybenzoate (MAFS);• 13 wt.% of 6-hydroxy 2-naphthoate (MAF2);• 12 wt. % of terephthalate;• 2 wt.% of isophthalate;• 16 wt.% of 4,4'-dihydroxybiphenolate (MAF1);• 14 wt.% of glass fibres.As can be seen, product (P) comprises the three monomers (MArx) of interest.

[0131] Example 2 - hydrolysis of the LCPs of product (P)

[0132] This example illustrates steps (a) and (b).

[0133] Product (P) (171 g) is loaded in a 2 L glass reactor with 96.95 g (2.4 mol) of sodium hydroxide pellets and 303 g of deionized (DI) water (16.8 mol). The mixture is mechanically stirred and heated to reflux for 8 hours. The suspension is diluted with 1143 g of deionized water and filtered over a 5 pm hydrophilic PVDF filter. 32 g of dry insoluble residue is recovered on the filter.

[0134] The inorganic content of the insoluble residue is determined by thermogravimetric analysis (TGA) to be 73 wt%. Thus, the insoluble fraction contains 23.2 g of insoluble (GF) and 8.8 g of residual polymer, out of the 150 g of polymer initially loaded in the composition.

[0135] The ratio of insoluble inorganic weight to initial loaded compound yields a 13.5 wt% content, compatible with the expected 14 wt% of GF content in the mixture.

[0136] The hydrolysis conversion (R) is thus 94%, based on polymer weight balance.20 SSPU 2024 / 044-WO-PCT

[0137] As demonstrated in this example, the hydrolyzed monomers are all soluble in the conditions of operation. This demonstrates that the fillers (here GFs), insoluble additives, metallic parts from the E&E connectors (E&E= Electrical & Electronics) can easily be removed by a filtration step for further recycling.

[0138] Example3: recovery of 4,4’-biphenol (aka 4,4’- dihydroxybiphenyl) of formula

[0139] This example illustrates recovery step (ci) to obtain (MAFI).

[0140] Precipitation substep (cal): the filtrate (1620g) of example 2 is taken over and pH is gradually adjusted to 9.0, by slow addition of hydrochloric acid (37 wt% aqueous), to induce the precipitation of 4,4’-biphenol mainly. The solid is recovered by filtration and dried overnight in vacuum oven at 90°C (21.5g).

[0141] The filtrate of precipitation is saved to recover other monomers (see below).

[0142] Purification substep (cb1): the dry solid is then washed by dispersing it into three times its weight of ultrapure water (65g). The pH is adjusted to 9.0. After 60 min stirring at 50°C, the solid is recovered by filtration (= solid A). The filtrate is gathered with the filtrate of the precipitation.

[0143] Using the same procedure, one other wash is achieved using ultrapure water, without any further pH adjustment (= solid B).

[0144] The following Table gives the composition of the solid fractions recovered, as determined by1H NMR. The yield of all the 4,4’-biphenol recovered at each step is expressed in % and based on the initial weight of 4,4’-biphenol present initially in product (P).

[0145] The followed procedure thus delivers a recycled 4,4’-biphenol with high purity (see solid A or solid B). Even though at each step, the overall yield of recovery of the 4,4’-biphenol initially present in product (P) decreases, it remains high.

[0146] Example 4: recovery of 6-hydroxy 2-naphthoic acid of formula21 SSPU 2024 / 044-WO-PCT

[0147] This example illustrates recovery step (C2) to obtain (MAr2).

[0148] Precipitation substep (ca2): the filtrate of example 3 (1650g) is taken over and pH is adjusted to 5.5, by slow addition of hydrochloric acid (37% aqueous), to induce the precipitation of 6-hydroxy 2-naphthoic acid mainly. The solid is recovered by filtration and dried overnight under vacuum at 90°C (13.3g).

[0149] Purification substep (cb2): the solid is then redispersed in three times its weight of ultrapure water (40g), adjusted to pH 5.5 by addition of HCI. The suspension is stirred for 1h at 50°C then filtered and dried again (= solid C). The filtrate is gathered with the filtrate of the precipitation.

[0150] The following gives the composition of the solid fractions (determined by1H NMR).

[0151] The following Table gives the composition of the solid fractions recovered, as determined by1H NMR. The yield of all the 6-hydroxy 2-naphthoic acid recovered at each step is expressed in % and based on the initial weight of 6-hydroxy 2- naphthoic acid present initially in product (P).

[0152] The followed procedure thus delivers a recycled 6-hydroxy 2-naphthoic acid with high purity (see values in Table above). Even though at each step, the overall yield of recovery of the 6-hydroxy 2-naphthoic acid initially present in product (P) decreases, it remains high.

[0153] Example 5: recovery of 4-hydroxy benzoic acid of formula:

[0154] This example illustrates recovery step (C3) to obtain (MAF3).22 SSPU 2024 / 044-WO-PCT

[0155] Precipitation substep (ca3): the saved filtrate of example 4 (1650g) is taken over and adjusted at pH 4.5 by addition of HCI 37%. A fraction rich in 4-hydroxy benzoic acid precipitates, is recovered by filtration and dried overnight under vacuum at 90°C (81.2g). The filtrate is saved for later recovery of the remaining monomers.

[0156] Purification substep (cb3): the dried solid fraction rich in 4-hydroxy benzoic acid is taken over with its same weight of ultrapure water and pH is adjusted to 1.0 to complete the neutralization of the 4-hydroxy benzoic acid sodium salt into the acid form. The solid is recovered by filtration and dried again in a vacuum oven overnight at 90°C (= solid D).

[0157] The 4-hydroxy benzoic acid is then extracted from the dry solid using acetic acid to separate it from the residues of terephthalic and isophthalic acids that partly coprecipitated. To do so, the solid is taken over and dispersed in 10 times its weight of pure acetic acid, stirred in a round bottom flask at 50°C for 1 h, using a rotavapor. The mixture is then filtered and a fraction rich in terephthalic and isophthalic acid is recovered as solid (= solid G). The composition of this solid is reported in Table below:.

[0158] The acetic acid is then distilled from the filtrate to recover a dried solid fraction containing 4-hydroxy benzoic acid (= solid E). The solid is finally washed with three times its weight of ultrapure water, stirred at 50°C for 1 h, then filtered and dried (= solid F).

[0159] The following Table gives the composition of the solid fractions recovered, as determined by1H NMR. The yield of all the 4-hydroxy benzoic acid recovered at each step is expressed in % and based on the initial weight of 4-hydroxy benzoic acid present initially in product (P).23 SSPU 2024 / 044-WO-PCT

[0160] The followed procedure thus delivers a recycled 4-hydroxy benzoic acid with high purity (see values in Table above). Even though at each step, the overall yield of recovery of the 4-hydroxy benzoic acid initially present in product (P) decreases, it remains high.

[0161] Example 6: recovery of the remaining monomers

[0162] This example illustrates recovery step (C4).

[0163] Precipitation substep (ca4): the filtrate (1750g) from Example 5 after precipitation of 4-hydroxy benzoic acid is taken over and adjusted to pH 1.5 using HCI. All the remaining monomers precipitate and are recovered by filtration, dried and analyzed by1H N MR (21g).

[0164] The composition of this fraction is reported in the following table.

[0165] It would be possible to perform an additional purification step (cb4) to further recover one or more of these monomers, including terephtalic and / or isophthalic acid.

[0166] It is noted that in the sequence of precipitation steps, we have:pH0(pH of So) > pHi (9.0) > pH2(5.5) > pH3(4.5) > pH4(1.5).

Claims

24 SSPU 2024 / 044-WO-PCTClaimsClaim 1. Method of preparation:i) of at least one monomer (MArx) or a Derivative thereof from a product (P), wherein said monomer is selected in the group consisting of:dihydroxybiphenyl (MAr1) of formula where each hydroxy group can occupy any one of the 5 positions present on the phenyl rings;6-hydroxy 2-naphthoic acid (MAr2); andhydroxybenzoic acid (MAr3) of formula(MAr1) being preferably 4,4’-dihydroxybiphenyl and / or (MAr3) being preferably 4- hydroxybenzoic acid;and / orii) a composition containing 6-hydroxy 2-naphthoic acid (MAr2) in combination with 4-hydroxybenzoic acid (MAr3);wherein product (P) comprises:® at least one polyester (PE);® optionally glass fibers (GF), typically present blended in one of more of the polyesters (PEs) present in product (P);® optionally at least one metallic component (MC);® optionally at least one plastic additive (Add), typically present blended in one of more of the polyesters (PEs);wherein the method comprises step (a) and optional step (b) as defined below:step (a): a basic aqueous solution is brought into contact with product (P) so as to obtain an aqueous liquid medium (Lo) exhibiting a pH > 7.0 and comprising the constituent monomers (Mi) of the polyester(s) (PE(s)) present in product (P); step (b): the insoluble material(s), notably the GFs (if any), the metallic component(s) (MG) or the plastic additive(s) (Add), that may be present in (Lo) are separated partially or totally;25 SSPU 2024 / 044-WO-PCTand the method further comprises after step (a) or (b) one or more recovery steps ( ), each step (q) comprising:• a precipitation substep (caj) to obtain a precipitate (PRj) enriched in a constituent monomer (Mj); and• optionally one or more purification substep (cbj) if monomer (Mi) is one of the aromatic monomers (MAFX), X being 1 , 2 or 3;where:o in step (caj): an acid (Ac) is brought into contact with an aqueous solution (Sj-i) comprising at least two constituent monomers (Mj) in order to decrease the pH of the aqueous solution (Sj-i) to obtain:■ a precipitate (PRj) comprising one constituent monomer (Mi) in the solid form with a proportion higher than 50.0 wt% (> 50.0 wt%) of monomer (Mi), this proportion being based on the total weight of precipitated constituent monomers (Mi) present in precipitate (PRj); and■ an aqueous solution (Sj), separated from precipitate (PRj):o in step (cbj): the purity (p) of the precipitated monomer (Mj) present in the precipitate (PRj) with the proportion > 50.0 wt% is increased by at least one separation method selected in the group consisting of recrystallization, distillation, washing and extraction, the separation step being either performed directly on the monomer (Mj) itself or to a derivative of said monomer, notably a Derivative of said monomer; where:- j is an integer greater than or equal to 1 corresponding to the jthstep ( ) used in the method, being understood that step ( +i ) is performed after step ( ); the aqueous solution (So) that is brought into contact with acid (Ac) in the first recovery step (ci) is the basic liquid medium obtained after step (a) or the basic aqueous solution obtained after step (b);the term “Derivative” (with capital D) designates a monomer where at least one -OH group is replaced by an ester group of formula -O-C(=O)-R where R is an optionally substituted (Ci-Cis)-hydrocarbyl group, more particularly an optionally substituted (Ci-Cis)-alkyl group;the Derivative of the monomer is prepared in a step (d) after step (c) wherein monomer (MArx) is converted into said Derivative or is recovered in a step (cbj).Claim 2. Method according to claim 1 , wherein polyester (PE) comprises at least 80.0 mol% of recurring units (RPE) selected in the group consisting of recurring units (RAr) of formula [-(Xi)-Ar-(X2)-] and recurring units (RCy) of formula [-C(=O)-Cy-C(=O)-] where:- Xi and X2are independently selected in the group of -O- and -C(=O)-;26 SSPU 2024 / 044-WO-PCT- Ar is selected from the group of phenylene, biphenylene and naphtylene groups; - Cy designate a cyclohexylene group, notably 1,3- and / or 1 ,4-cyclohexylene group.Claim 3. Method according to claim 1 or 2, wherein at the end of step (a), the pH of the aqueous basic liquid medium (Lo) is at least 11.0, preferably at least 12.0, preferably at least 13.0.Claim 4. Method according to any one of the preceding claims, wherein step (a) is performed at a temperature which is at least 50°C, preferably at least 80°C.Claim 5. Method according to any one of the preceding claims, wherein the proportion of base(s) used in the aqueous basic solution is such that molar ratio [base(s) / total amount of ester bonds from the polyester(s) (PE(s))] is from 1.1 to 10.0, preferably from 1.5 to 6.0, more preferably form 2.0 to 4.0, and even more preferably from 2.0 to 3.0.Claim 6. Method according to any one of the preceding claims, wherein the degree of conversion of polyester(s) (PE(s)) R achieved at the end of step (a) is preferably at least 90.0 wt %, preferably at least 93.0 wt % more preferably at least 95.0 wt %.Claim 7. Method according to any one of the preceding claims, wherein the base used in step (a) is selected in the group consisting of tertiary amines (e.g. triethylamine), pyridine, NaOH, KOH, Na2COs, K2CO3 and combinations thereof, preferably is NaOH or KOH.Claim 8. Method according to any one of the preceding claims, wherein prior to step (b), the constituent monomers that may be in the solid form in (Lo) are dissolved.Claim 9. Method according to any one of the preceding claims, wherein in the precipitation step, acid (Ac) is added, preferably at a controlled rate, to the stirred aqueous solution (Sj.1) to decrease its pH.Claim 10. Method according to any one of the preceding claims, wherein for one or more step (Cj) , (PROj) is greater than or equal to 60.0 wt% (> 60.0 wt%), preferably greater than or equal to 70.0 wt% (> 70.0 wt%), preferably greater than or equal to 80.0 wt% (> 80.0 wt%) where (PROj) is calculated by the following formula:PROj = proportion of precipitated constituent monomer (Mi) / total weight of the precipitated constituent monomers (Mi) present in precipitate (PRj) x 1001 SSPU 2024 / 044-WO-PCTClaim 11. Method according to any one of the preceding claims, wherein for one or more recovery step (cj) , the yield (Yj) of recovery of monomer (Mj) is higher than 50.0 wt% (> 50.0 wt%), this yield being calculated by the following formula:Yj = weight of monomer (Mj) present in precipitate (PRj) / weight of monomer (Mj) present in aqueous solution (Sj-i) x 100.Claim 12. Method according to any one of the preceding claims, wherein one obtains:- (MAr1); or- (MAr2); or- (MAr3); or(MAr1) and (MAr2); or(MAr1) and (MAr3); or(MAr2) and (MAr3); or- (MAr1) and (MAr2) and (MAr3).being understood that one or more of these monomers may be in the form of a Derivative and that the molecule(s) (MArx or Derivative thereof) so prepared are preferably Purified.Claim 13. Method according to any one of the preceding claims, wherein j i.Claim 14. Method according to any one of the preceding claims, wherein product (P) comprises:® at least one polyester (PE);® glass fibers (GF);® optionally at least one metallic component (MC);® optionally at least one plastic additive (Add),or comprises:® at least one polyester (PE);® glass fibers (GF);® at least one metallic component (MC);® optionally at least one plastic additive (Add).Claim 15. Method according to any one of the preceding claims, wherein polyester (PE) is selected in the group consisting of:aromatic polyesters, semi-aromatic polyesters and polyesteramides; or28 SSPU 2024 / 044-WO-PCTaromatic polyesters, semi-aromatic polyesters, polyesteramides and combination thereof; oraromatic polyesters, semi-aromatic polyesters and combination thereof; or aromatic polyesters.Claim 16. Method according to any one of the preceding claims, wherein the total proportion in (Lo) of the aromatic monomer(s) (MAFX) is at least 5.0 wt%, preferably at least 10.0 wt%, this proportion being expressed relative to the total amount of constituent monomers (Mi) present in (Lo).Claim 17. Method according to any one of the preceding claims, wherein (MAF1) is 4,4’-dihydroxybiphenyl and / or (MAF3) is 4-hydroxybenzoic acid.Claim 18. Method according to any one of the preceding claims, wherein the metallic component (MC) is based on or comprises (i) a metal selected in the group consisting of copper, aluminium and combination thereof or (ii) an alloy selected in the group consising of brass, steel and combination thereof.Claim 19. Method according to any one of the preceding claims, wherein the reaction mixture (RM) of step (a) comprising water, product (P) and at least one base is free of polar solvent (S) selected in the group consisting of methanol, tetrahydrofuran, 1,4-dioxane, N,N- dimethylformamide and combination thereof, the expression "free of" meaning that the proportion p of polar solvent in the reaction mixture (RM) is lower than or equal to 50.0 wt% (< 50.0 wt%), preferably lower than or equal to 25.0 wt% (< 25.0 wt%), preferably lower than or equal to 10.0 wt% (< 10.0 wt%), preferably lower than or equal to 5.0 wt% (< 5.0 wt%), preferably lower than or equal to 1.0 wt% (< 1.0 wt%), this proportion being calculated by the following equation:p (wt%) = proportion by weight of polar solvent in RM / [proportion by weight of polar solvent in RM + proportion by weight of water in RM] x 100.Claim 20. Method according to any one of the preceding claims, wherein the reaction mixture (RM) of step (a) comprising water, product (P) and at least one base is:free of an organic solvent; orfree of an organic solvent selected in the group consisting of alcohols, cyclic ethers and solvents containing amide bonds;the expression "free of" meaning that the proportion p of organic solvent in the reaction mixture (RM) is lower than or equal to 50.0 wt% (< 50.0 wt%), preferably lower than or equal29 SSPU 2024 / 044-WO-PCTto 25.0 wt% (< 25.0 wt%), preferably lower than or equal to 10.0 wt% (< 10.0 wt%), preferably lower than or equal to 5.0 wt% (< 5.0 wt%), preferably lower than or equal to 1.0 wt% (< 1.0 wt%), this proportion being calculated by the following equation:p (wt%) = proportion by weight of organic solvent in RM / [proportion by weight of organic solvent in RM + proportion by weight of water in RM] x 100.Claim 21. Method according to any one of the preceding claims, wherein Purified (MAF3) is obtained when liquid medium (Lo) comprises (MAF3) as one of the constituent monomers.Claim 22. Method according to any one of the preceding claims, wherein terephthalic and / or isophthalic acid is / are also recovered, notably Purified terephthalic and / or isophthalic acid.Claim 23. Method according to any one of the preceding claims, wherein in the sequence of precipitation steps,the pH of precipitation used in step (ca,) noted pHj is such that pHj.i > pHj where pHj.i is the pH of precipitation used in step (caj.i); andpH of (So) > pHi of step (cai).Claim 24. Method according to any one of the preceding claims, wherein the pH of (So) is at least 11.0, preferably at least 12.0, preferably at least 13.0.

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