Process for treating contaminated polyester recovery feedstock

Abstract

Disclosed is a method for recovering polyester from a contaminated polyester recovery feedstock that includes polyester and one or more contaminants. The method of the present disclosure includes the steps of (a) treating the contaminated polyester recovery feedstock in a treating zone with at least one solvent under conditions in which the polyester and at least one of the one or more contaminants are substantially solubilized in the solvent, forming treating zone product comprising solubilized polyester and, optionally, one or both of solubilized contaminant and insoluble contaminant; (b) separating insoluble contaminant from the treating zone product to form a solubilized polyester recovery intermediate comprising solubilized polyester and, optionally, solubilized contaminant; and (c) recovering said solubilized polyester in a polyester recovering zone to form a recovery product comprising (i) target polyester and optionally (ii) residual contaminants. The method may further include modifying the target polyester to form various target products.

Description

PROCESS FOR TREATING CONTAMINATED POLYESTER RECOVERY FEEDSTOCKFIELD OF THE INVENTION

[0001] The present invention generally relates to the field of polyester recycle and recovery processes and more particularly to polyester recycle or recovery processes that include recovery of polyester, e.g., using dissolution or depolymerization or a combination thereof, from feedstocks that may include polyester with a variety of contaminants.BACKGROUND OF THE INVENTION

[0002] Polyesters are often viewed as the world's most purchased and diversely utilized class of polymers, with published world production volumes (including recycling) recently reported to be well in excess of 75 million tons. This level of commercial success is likely attributable in part to polyesters’ attractive combination of relative cost, manufacturability and competitive performance attributes. Polyester’s physical, chemical and thermal properties make them useful and desirable for a wide variety of end-use applications. Polyethylene terephthalate (PET) is probably one of the most popular types of polyester for many end-uses. With the continuing commercial success of polyesters generally and PET specifically has come efforts to recover materials from post-consumer, post-industrial, scrap and other sources and re-use those materials as an alternative to basic disposal methods such as landfills.

[0003] In some known recycle methods, recycled PET is blended with virgin materials. This approach has been used, for example, to prepare blends of virgin poly(butylene terephthalate) (“PBT”) with recycled PET to yield a PBT- based product with recycle content (see, for example, U.S. Patent Application Publication No. 2009 / 0275698). Such blends, however, can be generally immiscible and produce a material that is relatively opaque. Blending, therefore, is not a uniformly satisfactory method to provide commercially acceptable end products with recycled content.

[0004] In some known recycle methods, polyesters may be selectively dissolved and recovered as a solution for further processing. For example, in U.S. Patent No. 4,003,880, polyester polymer is recovered from mixed collections of fibers in the form of fibers, filaments, or fabrics (including dyed or undyed fibers other than polyester fibers as well as dyed polyester fibers) and used in the production of new undyed fibers, films and other polymer products through the process of stripping the dye from the polyester fibers by contacting the fabrics with a dye stripping solvent for polyester polymer which is preferably not a solvent for fibers other than polyester fibers at a temperature below which the polyester fibers dissolve and above which the crystalline lattice of the polyester fibers swell so as to release the dye; then removing essentially all of the dye-containing dye-stripping solvent which is not absorbed by the fibers; then contacting the solvent-laden fibers (which may contain residual dye) with sufficient additional solvent under selective dissolution conditions for polyester fibers; then removing the undissolved fibers and any other undissolved impurities from the solution; thereafter separating the polyester from the solution.

[0005] In other recycle methods, polyesters are depolymerized to form the monomer units originally used in its manufacture. Glycolysis is one commercially utilized method of depolymerizing polyesters. A typical glycolysis process can be illustrated with particular reference to the glycolysis of PET, in which waste PET is dissolved in and reacted with a glycol, typically ethylene glycol, to form a mixture of dihydroxyethyl terephthalate and low molecular weight terephthalate oligomers. This mixture can be subjected to a transesterification reaction, usually in the presence of an ester exchange catalyst, with a lower alcohol such as methanol to form dimethyl terephthalate (DMT) and ethylene glycol(EG), and other monomers, again depending upon the composition of the waste or scrap polyester feedstock. Representative examples of glycolysis methods are disclosed in U.S. Pat. Nos. 3,257,335; 3,907,868; 6,706,843; and 7,462,649, the contents and disclosure of which are hereby incorporated herein by reference.

[0006] Methanolysis is another known and commercially practiced polyester depolymerization method. In methanolysis, the polyester is reacted with methanol as a depolymerization reagent to produce a depolymerized polyester mixture comprising polyester oligomers, dimethyl terephthalate (“DMT”), and ethylene glycol (“EG”). Other monomers such as, for example, 1 ,4- cyclohexanedimethanol (“CHDM”) and diethylene glycol may also be present depending on the composition of the polyester in the methanolysis feed stream and may be target products for certain polyester depolymerization processes. Some representative methods for the methanolysis of PET are described in U.S. Pat. Nos. 3,037,050; 3,321 ,510; 3,776,945; 5,051 ,528; 5,298,530; 5,414,022; 5,432,203; 5,576,456 and 6,262,294, the contents and disclosure of which are incorporated herein by reference. A representative methanolysis process is also illustrated in U.S. Pat. No. 5,298,530, the contents and disclosure of which is incorporated herein by reference. The ‘530 patent describes a process for the recovery of ethylene glycol and dimethyl terephthalate from scrap polyester. The process includes the steps of dissolving scrap polyester in oligomers of ethylene glycol and terephthalic acid or dimethyl terephthalate and passing super-heated methanol through this mixture. The oligomers can comprise any low molecular weight polyester polymer of the same composition as that of the scrap material being employed as the starting component such that the scrap polymer will dissolve in the low molecularweight oligomer. The dimethyl terephthalate and the ethylene glycol are recovered from the methanol vapor stream that flows from the depolymerization reactor.

[0007] One of the biggest challenges in cost-effective polyester recovery related recovery of useful polyester depolymerization target products such as EG and DMT is the presence of materials, generally referred to herein as “contaminants”, in the recovery process feedstock. Polyester recovery feedstocks may typically be sourced from plastics recycle collection facilities and similar services or organizations which receive, store and process with limited sorting large quantities of waste plastics for recycle. These collections often include a diverse assortment of many different types and classes ofpolymer materials, including polyesters, polyolefins such as polyethylene and polypropylene, polyamides such as Nylon 6, Nylon 6,6, and MDX Nylon, elastanes such as Spandex™ and Lycra™, polycarbonates, and polysilicones such as polydimethylsiloxane (PDMS). Further, the waste may include composite materials such as agglomerates, laminates, multilayer films, coated substrates and adhered components that may include multiple plastics materials; additives such as dyes and plasticizers; and catalysts and catalyst residues from the materials original manufacture. The waste may also include impurities such as dirt, glass, paper, minerals, and other non-polymer materials that may also pass through the depolymerization reactor or generate undesirable by-products.

[0008] Whether the contaminant is a polymer, an additive or an impurity, their presence in a waste collection that is a potential source of a polyester recovery feedstock may be problematic. Some contaminants may simply pass through a polyester recovery process unchanged and contaminate the recovery product stream if not removed. Some contaminants may generate (and / or catalyze the formation of) undesirable by-products in the course of polyester depolymerization that, in addition to contaminating the depolymerization product stream, may negatively impact the depolymerization reaction or related target product yield or quality. By way of non-limiting example, Bisphenol-A may be present in a polyester depolymerization product stream when polycarbonate materials are present in the depolymerization feedstock while diesters of adipic acid such dimethyl adipate may be present in a polyester depolymerization product stream when the feedstock includes polyamide materials.

[0009] Separation and subsequent disposal of side-species, by-products and contaminants from the various processing streams within, and / or the final target product stream of, a polyester recovery or depolymerization process can be expensive, capital-intensive, time-consuming and environmentally problematic. The commercial value or utility of at least some of the side species may be changed or improved by conversion to other more useful or valuablecompounds; however, this conversion almost certainly adds additional processing steps (and therefore cost) to the process and must be managed to avoid negative impacts on target product conversion, yield and purity.

[0010] The removal of as many contaminants as possible from the feedstock for a polyester recovery process may reduce the need for contaminant, byproduct etc. removal within or during subsequent processing such as depolymerization or transesterification. Further, removal of as many contaminants as possible from the feedstock for a polyester recovery process may facilitate or enable recovery of polyester per se or modified forms thereof. To that end, U.S. Published Patent Application No. 2022 / 0169822A1 describes pre-treating a waste polyester material with dichloromethane (DCM) produce purified polyesterthat can be recycled via any chemical or mechanical recycling process. The described method uses dichloromethane, which is insufficient to properly handle the wide palette of contaminants in recycle collection and which per public information has serious health risks. A continuing and unmet need therefore exists for a method to treat feedstocks for polyester recovery processes that meets environmental standard criteria, minimizes worker hazards, effectively removes contaminants therefrom and facilitates recovery of the polyester per se as well as target products from polyester modification methods such as depolymerization.SUMMARY OF THE INVENTION

[0011] In an aspect, the present invention relates to a method for recovering polyester from a contaminated polyester recovery feedstock that includes polyester and one or more contaminants. The method includes the steps of (a) treating the contaminated polyester recovery feedstock in a treating zone with at least one solvent under conditions in which the polyester and at least one of the one or more contaminants are substantially solubilized in the solvent, forming treating zone product comprising solubilized polyester and, optionally, one or both of solubilized contaminants and insoluble contaminant; optionally (b) separating the insoluble contaminant from the treating zone product to forma solubilized polyester recovery intermediate comprising solubilized polyester and, optionally, solubilized contaminant; and (c) recovering said solubilized polyester in a polyester recovering zone to form a recovery product comprising (i) target polyester and optionally (ii) residual contaminants.

[0012] Further aspects of the invention are as disclosed and claimed herein.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a diagrammatic depiction of at least one exemplary embodiment of the present invention relating to a method for recovering polyester from a contaminated polyester recovery feedstock that includes polyester and one or more contaminants;

[0014] Figure 2 is a diagrammatic depiction of another exemplary embodiment of the present invention relating to a method for recovering polyester from a contaminated polyester recovery feedstock that includes polyester and one or more contaminants;

[0015] Figure 3 is a diagrammatic depiction of yet another exemplary embodiment of the present invention relating to a method decontaminating a contaminated polyester recovery feedstock that includes polyester and one or more contaminants; and

[0016] Figure 4 is a diagrammatic depiction of still another exemplary embodiment of the present invention relating to a method for recovering polyester from a contaminated polyester recovery feedstock that includes polyester and one or more contaminants.DETAILED DESCRIPTION

[0017] The term “polyester” as used herein is meant to generally include without limitation homopolyesters as well as copolyesters, terpolyesters and the like and are typically prepared by reacting a difunctional carboxylic acid or its ester, often a dicarboxylic acid, or mixtures of such acids or esters, with a difunctional hydroxyl compound, often a diol or glycol, or mixtures of such diols or glycols. Alternatively, the difunctional carboxylic acid may be a hydroxycarboxylic acid and the difunctional hydroxyl compound may be an aromatic nucleus bearing 2 hydroxyl substituents such as, for example, hydroquinone. Examples include polyesters having repeating aromatic or cyclic units such as those containing a repeating terephthalate or naphthalate units such as PET and PEN, or those containing repeating furanate repeating units, and although within the definition of PET, it is worth mentioning also those polyesters having repeating terephthalate units and one or more residues or moieties of TMCD (2,2,4,4-tetramethyl-1 ,3-cyclobutanediol), CHDM (cyclohexanedimethanol), propylene glycol, or NPG (neopentylglycol), isosorbide, isophthalic acid, 1 ,4- butanediol, 1 ,3-propane diol, and / or diethylene glycol, or combinations thereof and aliphatic polyesters such as PLA, polyglycolic acid, polycaprolactones, and polyethylene adipates; Polyesters and polyester manufacture are generally well known and are exemplified in for example U.S. Patent Nos. 2,891 ,930 and 2,720,502, assigned to a legacy assignee of the present invention, the contents and disclosure of which are incorporated herein by reference.

[0018] A “polyester recovery process” as the phrase is used herein includes any method, process or system for treatment of polyester-containing feedstocks under conditions to produce or generate target products such as for example polyester, a modified polyester, a co-polyester and / or one or more oligomers or monomers from which polyester may be formed. Non-limiting examples include one or more of (i) dissolution of the polyester component of the feedstock to recover the polyester in solution or a precipitate derived from polyester in solution; polyester depolymerization methods including without limitation methanolysis depolymerization; alcoholysis depolymerization, e.g., using 2-ethylhexanol as the depolymerizing alcohol; glycolysis depolymerization; pyrolysis depolymerization; hydrolysis depolymerization; and catalyzed reaction of hydrogen with polyester at its ester bonds to reduce them to alcohols (which may be referred to as hydrogenolysis depolymerization); and transesterification of polyester to form modified polyesters or copolyesters.

[0019] The phrase “target product” is used herein to describe one or more of (i) polyester present in a decontaminated polyester recovery feedstock orrecovery product from a polyester recovering zone in any form and / or derivatives thereof, expressly including but not limited to modified polyesters or copolyesters formed by transesterification thereof; (ii) useful compound(s) or material(s) from depolymerized polyester (a) on which oligomeric or monomeric unit(s) of a polyester are based and / or (b) are generated in the course of a polyester depolymerization process or the depolymerization of a polyester. Specific non-limiting examples of (ii) above may include dimethyl terephthalate (DMT), dimethyl isophthalate (DMI), or mixtures of DMT and DMI; Bis(2- Hydroxyethyl) terephthalate (BHET); Mono(2-hydroxyethyl) terephthalate (MHET); glycols such as ethylene glycol (EG) as for example when the polyester subject to depolymerization is polyethylene terephthalate (PET); diols such as cis- or trans-cyclohexane-1 ,4-dimethanol (CHDM) or mixtures thereof, cis- or trans- cyclohexane-1 ,3-dimethanol (CHDM) or mixtures thereof; cis- or trans-cyclobutane-2,2,4,4-tetramethyl-1 ,3-dimethanol (TMCD) or mixtures thereof; diethylene glycol (DEG), neopentylglycol, 1 ,3-propanediol, 1 ,4- butanediol, triethylene glycol, and mixtures such as a mixture of DEG and EG; and 1 ,4-phenylenedimethanol or similar 1 ,3- or 1 ,2- phenylenedimethanol isomers.

[0020] The term “zone” is intended to describe a collection of one or more interconnected and potentially overlapping unit operations and related devices assembled to contribute to achievement of a related system or method purpose or purposes. In non-limiting examples relevant to the present invention, a “depolymerization zone” may include a reacting or depolymerizing operation employing suitable apparatus or systems such as a reactor or depolymerizer; a “separating zone” may include one or more unit operations to separate various components of a multicomponent material, such as separating, extracting, distilling, evaporating, condensing, decanting, crystallizing, precipitating, filtering and the like employing suitable apparatus such as a extractor, distillation column, evaporator, condenser, decanter, crystallizer, filter and the like. A “recovery zone” may include one or more unit operations to recover one or more components for re-use, recycle or further processing such asseparating, extracting, distilling, evaporating, condensing, decanting, crystallizing, precipitating, filtering and the like employing suitable apparatus such as a extractor, distillation column, evaporator, condenser, decanter, crystallizer, filter and the like. Zones may overlap though diagrammatically depicted as separate in the Figures for convenience.

[0021] The present invention is described herein with respect to various interrelated aspects and embodiments, including but not limited to a method for decontaminating a contaminated polyester recovery feedstock that includes polyester and at least one contaminant and a method for recovering or depolymerizing polyester. One of ordinary skill will understand and appreciate that elements or features used to describe one aspect or embodiment may be applicable and useful in describing other embodiments. Accordingly, descriptions and disclosure relating to elements or features of an aspect or embodiment of the present invention are hereby expressly relied on to describe and support those elements or features in other aspects or embodiments.

[0022] The present invention, in a first aspect and with reference to Figures 1 through 4, is directed to a method for decontaminating a contaminated polyester recovery feedstock 1 that includes polyester and one or more contaminants. As the contaminated polyester recovery feedstock may include dyed polyester or dyed contaminant, the contaminated polyester recovery feedstock may include contaminant dye, for example as a component of the dyed polyester or dyed contaminant. In one or more exemplary embodiments, the polyester may be in solid or solid particulate form. In one or more exemplary embodiments, the method may optionally include a step of procuring a contaminated polyester recovery feedstock including polyester and at least one contaminant. The procuring step may include one or more suitable procurement methods or systems or processes, including by way of non-limiting example collecting or assembling or having collected or assembled contaminated polyester recovery feedstock; receiving, purchasing or otherwise obtaining a contaminated polyester recovery feedstock from another party such as plastics recycler and the like.

[0023] The method of this aspect of the present invention may include the steps of (a) treating the contaminated polyester recovery feedstock in a treating zone with at least one solvent under conditions in which the polyester and at least one of the one or more contaminants are substantially solubilized in the solvent, forming treating zone product comprising solubilized polyester and, optionally, one or both of solubilized contaminant and insoluble contaminant; optionally (b) separating the insoluble contaminant from the treating zone product to form a solubilized polyester recovery intermediate comprising solubilized polyester and solubilized contaminant; and (c) recovering said solubilized polyester in a polyester recovering zone to form a recovery product comprising (i) target polyester and optionally (ii) residual contaminants. Terms and phrases such as “solubilized”, “unsolubilized” and “insoluble” are intended to reflect and describe the condition of polyester and / or contaminants under the conditions of the treating step, it being understood that solubility of individual species may be dependent on conditions such as identity and amount of polyester, contaminant identity and amount, temperature, pressure, solvent amount and concentration and the like.

[0024] As depicted in Figures 1 through 4, the treating step (a) may be performed in a treating zone 10 and optional separating step (b) may be performed in a separating zone 30. The contaminated polyester recovery feedstock 1 and solvent 2, as well as one or more additional solvents 3 for some embodiments, may be fed into treating zone 10. Though depicted as separate streams in the Figures, one will appreciate that the depicted streams may be combined prior to treating step or may be introduced into treating zone 10 sequentially or concurrently or simultaneously or in any order or combination. T reating zone 10 may include any suitable vessel or vessels such as one or more of a mixing tank, reactor, columnar vessel, or the like or combinations thereof. Product from treating zone 10, shown for example at 4 in the Figures, includes solubilized polyester. Treating zone product 4 may further include (in one or more streams) one or more of solubilized contaminant, insoluble contaminant and carrier liquid that may include one or more solvents.

[0025] The contaminated polyester recovery feedstock may include polyester, and one or more contaminants. The contaminated polyester recovery feedstock may include polyester and one or more contaminants wherein the contaminant includes at least one contaminant dye. A “contaminant” as the term is used herein generally includes any polymeric, oligomeric, organic or inorganic materials present in a polyester recovery feedstock other than polyesters. Specific non-limiting examples of contaminants may include polymers, including polyolefins such as polyethylene and polypropylene and copolymers thereof; polyamides such as Nylon 6, Nylon 6,6, and MDX Nylon; elastanes such as Spandex™ and Lycra™, polycarbonate, and silicones such as polydimethylsiloxane (PDMS) and PVC, including polyunsaturated backbones depleted in chlorine (as compared to virgin PVC) which may be generated via PVC decomposition during the treating step of the method of the present invention. Contaminants may also include composite materials such as agglomerates, laminates, multilayer films, fibers, woven fabrics, meshes, coated substrates and adhered components that may include one or more polymer, oligomer or organic materials that may be contaminants; additives such as dyes and plasticizers; adhesives such as ethylene-vinyl alcohol and polyurethane adhesives; catalysts and catalyst residues, e.g., from a material’s original manufacture; packaging materials such as paper, cardboard, wood, including said materials coated with clay, plastics, waxes, and the like; general waste or detritus, such as stones, pebbles, rocks, food residue, metal implements or artifacts such as screws, wire, pop tops, and the like.

[0026] The method of the present invention may include treating the contaminated polyester recovery feedstock with at least one solvent. The term “solvent” is intended to describe material that substantially solubilizes at least one of polyester and at least one of the one or more contaminants during the treating step at the conditions under which the treating step is performed. As discussed herein, the treating step may include treatment with one solvent or more than one solvent.

[0027] In at least one exemplary embodiment, at least one of said one or more contaminants is substantially solubilized in the treating step, forming treating zone product 4 that includes at least one solubilized contaminant, solubilized polyester and optionally at least one insoluble contaminant. “Insoluble” or “unsolubilized” as used herein is intended to describe contaminant which remain primarily in a generally solid form during and immediately exiting the treating step (or substep thereof) as a component of the treating zone product. By way of example, contaminant material that may be undissolved or may be partially or completely swelled during the treating step and under the treating step conditions may be described as “insoluble”. Nonlimiting examples of insoluble contaminants include cotton / cellulose, regenerated cellulose (rayon); carbon black; metals, exemplified by aluminum, steel, copper and other metallic artifacts, such as wires, pop tops, screws, nails, textile detritus, including zippers, snaps, buttons, rivets, and the like; inorganics exemplified by TiO2, silicon dioxide, clays, rocks, gravel, pebbles and the like. In one or more exemplary embodiments, the treating step (a) forms a treating zone product or effluent, shown at 4 as product in the Figures, includes solubilized polyester and may further include one or both of solubilized contaminant and optionally insoluble contaminants, in one or more streams. In one or more exemplary embodiments, the treating step (a) forms a treating zone product including solubilized polyester and solubilized contaminant. In one or more exemplary embodiments, the treating step (a) forms a treating zone product including solubilized polyester and insoluble contaminant. In one or more exemplary embodiments, the treating step (a) forms a treating zone product including solubilized polyester, solubilized contaminant and insoluble contaminant.

[0028] As depicted in the Figures, the treating step may include in some embodiments include at least partial separation functionality enabling separation of solubilized polyester from solubilized contaminant and / or insoluble contaminant, such that treating step (a) also forms a treated contaminant effluent, shown at 5, that includes one or both of insolublecontaminant and solubilized contaminant. Treated contaminant effluent 5 may be formed for example in embodiments where the treating step includes sequential substeps as described elsewhere herein. To the extent the contaminant in treated contaminant effluent 5 may be useful for recovery or reuse, the contaminant may be recovered in treated contaminant recovery zone 20 to form recovered treating step contaminant 8 as shown in Figures 3 and 4. Suitable recovery methods may include one or more of dewatering techniques such as centrifugation, pressing, augering; drying; evaporation; incineration; adding water as a contaminant recovery enhancement agent, combined with distilling via azeotropic distillation. Said recovery methods may be accomplished batchwise or continuously, with one or more of the methods occurring sequentially. In one or more embodiments, treated contaminant effluent 5 may include solvent which is separated from contaminant in treated contaminant recovery zone 20 and optionally recycled to treating zone as shown at 21 in Figures 3 and 4.

[0029] One of ordinary skill will appreciate that the materials present in treating zone product 4 and (where applicable) treating zone contaminant effluent 5, may vary based on a number of factors, including without limitation the materials present in the feedstock 1 . For example, in embodiments where feedstock 1 does not include insoluble contaminant, neither treating zone product 4 nor (where applicable) treating zone contaminant effluent 5 will include insoluble contaminant.

[0030] To reduce the amount of contaminated polyester recovery feedstock 1 that must be treated, in at least one exemplary embodiment, polyester may be partially removed from the contaminated polyester recovery feedstock, or polyester and contaminants may be separated from the contaminated polyester recovery feedstock, for example by density separation, prior to or concurrent with treating step a). Accordingly, in one or more exemplary embodiments, the method of the present invention may include, prior to treating step (a), a step of removing or segregating one or both of polyester and contaminant from the contaminated polyester recovery feedstock 1. In one or more exemplaryembodiments, this removing or segregating step may include the separating polyester from the polyester-containing contaminated polyester recovery feedstock by density separation. Examples of density separation are known in the art and include flotation separation, static media density separation, gravity separation, magnetic density separation and hydrocyclone separation such as separation with cylindroconical and cylindrical cyclone-type media separators. In one non-limiting example, the density of relatively pure polyethylene terephthalate (PET) may be from 1.3 to 1.4 g / cc and this PET will sink in aqueous salt solutions with densities less than 1 .3 g / cc. In contrast, composite polyethylene-PET materials may have densities less than 1 .2 g / cc, and thus can be separated from relatively pure PET. In one non-limiting example, known as “sink / float” or “flotation” density separation, a component that is less dense than a carrier floats to or near its surface while a second component that is more dense than that carrier does not float to the surface of the carrier or may sink to or near its bottom. “Flotation” density separation, as well as other density differential separation techniques, are described for example in U.S. Patent No. 4,617,111 , the contents and disclosure of which are hereby incorporated herein by reference.

[0031] In at least one exemplary embodiment, the at least one contaminant may include a polymer. In at least one exemplary embodiment, the at least one contaminant may be selected from the group consisting of polyolefins, polyurethanes, elastanes, PVC, polyamides, silicones, polycarbonates, cotton, cellulose, regenerated cellulose, dyes and combinations thereof.

[0032] In at least one exemplary embodiment, the at least one contaminant may be selected from the group consisting of polyolefins, polyurethanes, elastanes, PVC, polyamides, silicones, adhesives such as ethylene-vinyl alcohols and polycarbonates, plasticizers, dyes and combinations thereof. In one or more exemplary embodiments, the at least one solvent may be selected from a group consisting of one or more of C3 to C11 ketones, including in particular acetone and a mix of C11 ketones commercially available from Eastman Chemical; more preferably C3-C9 ketones such as acetone, methylpropyl ketone (MPK), methyl amyl ketone (MAK), methyl isoamyl ketone (MIAK), di-isobutyl ketone (DIBK), methyl iso-butyl ketone (MIBK), di-isopropyl ketone (DIPK), methyl isopropyl ketone (MIPK) and combinations such as mixes of C7 or C9 ketones sold by Eastman Chemical; C6 to C12 aromatics such as naphthalenes, toluene, xylenes and mixed xylenes, preferably C7 to C10 aromatics; aromatic fluids known in the art as Aromatic 150, Aromatic 200, Solvesso™ 150 and Solvesso™ 200 and sold commercially by Exxon Mobil™ and combinations; C6 to C14 alkanes, preferably C7 to C11 alkanes such as undecane, isoparaffin fluids such as Isopar™ L; C4 to C10, preferably C5 to C8, aliphatic esters, such as ethyl, propyl, butyl, acetates, propionates, and butyrates; C8 to C12, preferably C8 to C1 , aromatic esters; C3 to C6 aliphatic secondary and tertiary amides; C5-C8 secondary and tertiary lactams and similar cyclic amides, exemplified by N-methyl-2-pyrrolidone (NMP), N-ethyl-2- pyrrolidone, N-propyl-2-pyrrolidone, N-butyl-2-pyrrolidone, dimethylacetamide, diethylacetamide, dimethyl propanamide, dimethyl butanamide, dimethylformamide, diethylformamide and 1 ,3-Dimethyl-2-imidazolidinone, C1 to C10 alkanols and glycols, as exemplified by methanol, ethanol, propanol isomers, butanol isomers, cyclohexanol, ethylene glycol, diethylene glycol, triethylene glycol, CHDM, propanediol and butanediol isomers; C4 to C10 glycol ethers and glycol ether carboxylate esters, exemplified by EG, DEG, and 1 ,2- PDO mono ethers of ethanol, propanol, and butanol and corresponding esters, EG, 1 ,2-PDO, and DEG diethers of ethanol, propanol, and butanol; C7 to C10, preferably C7 to 08, aromatic alcohols; 02 to 06 carboxylic acids, preferably C2 to 04 carboxylic acids such as acetic propionic, and butyric acid isomers; C2 to 04 carboxylic acids with soluble salts of Group II A cations with anions selected from chloride, bromide, acetate, propionate, lactate, trifluoracetate, triflate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, chloroacetate wherein said salt is soluble in said solvent at least at a 0.25M concentration, preferably 02 to 03 carboxylic acids with Ca and Mg salts of chloride, acetate, propionate, lactate, trifluoroacetate, triflate and nitrate; C1 to C4 alkanols with soluble salts of Group II A cations with anionsselected from chloride, bromide, acetate, propionate, lactate, trifluoracetate, triflate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, chloroacetate wherein said salt is soluble in said solvent at least at a 0.25M concentration, preferably C1 to C2 alkanols with Ca and Mg salts of chloride, acetate, propionate, lactate, trifluoroacetate, triflate and nitrate and combinations thereof. In at least one exemplary embodiment, the calcium salt may be an organic calcium salt such as for example calcium acetate or calcium lactate, or a halo-organic calcium salt such as calcium trifluoroacetate or calcium triflate.

[0033] Mixtures of two or more solvents are also contemplated, including for example a mix of xylene and a C7 ketone; a mix of Aromatic 150 and a C7 to C9 ketone; and a mix of Aromatic 200 with a C9 ketone. In one or more embodiments, the solvent may be a mixture of aromatic or amide and C2 to C8 glycols, preferably ethylene glycol, diethylene glycol, CHDM, triethylene glycol, wherein the mixture includes 5-50 wt% glycol with the remainder aromatic or amide. A glycol / amide mixture may be particularly efficacious for contaminated polyester recovery feedstocks comprising crystalline or semi-crystalline polyester of large particle size (i.e., greater than 5 mm average diameter chunks), with the glycol believed to assist in large particle dissolution by swelling the polyester matrix and promotes transformation into a friable solid. Accordingly, in some embodiments, the treating step or a substep thereof may include swelling the polyester with a swelling agent such as glycol. In some embodiments, the treating step may further include solubilizing the polyester with a solvent, with suitable solvents including, without limitation C10-C14 aromatics, C1-C10 alkanols, C2-C6 glycols, C5-C8 secondary or tertiary cyclic amides, C3-C6 secondary or tertiary aliphatic amides, C8-C12 aromatic esters and C7-C10 aromatic alcohols. Accordingly, the at least on e solvent of the treating step may include one or more of C10-C14 aromatics, C1 -C10 alkanols, C2-C6 glycols, 05-08 secondary or tertiary cyclic amides, 03-06 secondary or tertiary aliphatic amides, C8-C12 aromatic esters and 07-010 aromatic alcohols.

[0034] In general, the treating step may be performed under conditions to achieve maximum solubilization of polyester, and of at least one contaminant without substantial solubilization of other contaminants that (as unsolubilized) may be described as “insoluble”. In one or more exemplary embodiments, the treating step may be performed under conditions sufficient to maintain the treating step in the liquid phase such that the treating step product includes a carrier liquid such as solvent. One of ordinary skill may appreciate that conditions for the treating step may vary and may be selected based on several factors including without limitation type, number and physical form (including particle size) of contaminant(s), and choice and amount and concentration of solvent. In one or more exemplary embodiments, the treating step may be performed under conditions of high shear, mixing or similar agitation. In one or more exemplary embodiments, the treating step may be performed at a temperature of from 20°C to 230°C. In one or more exemplary embodiments, the treating step may be performed at a pressure of from about 1 bara to 15 bara. In one or more exemplary embodiments, the time or period for the treating step may be from 30 seconds to 6 hours. In one or more exemplary embodiments, the treating step or a substep thereof may be performed at a modification mass ratio (MMR), defined as the mass ratio of solvent to polyester present in the contaminated polyester recovery feedstock, of 3 / 1 to 20 / 1 , preferably 4 / 1 to 10 / 1. As used herein, exemplary MMR levels relate primarily to and are described for the primary purpose of achieving polyester solubilization and (in applicable embodiments) contaminant solubilization. Excess solvent may nonetheless be included, for example, to create additional effects such as fluidity or flowability of the system or to function as a carrier liquid for the treating zone product while remaining within the spirit and scope of the invention.

[0035] In embodiments in particular wherein the contaminated polyester recovery feedstock includes dyed material, for example at least one of dyed polyester and dyed contaminant non-polyester, treating step conditions may be selected to facilitate leaching of the dye from the dyed material as well assolubilization of the dye. Accordingly, in one or more embodiments, the treating step may include leaching contaminant dye from dyed material or from one or more of dyed polyester and dyed contaminant non-polyester. As used herein, the term “leaching” is intended to generally describe removal of solute into a solvent from solid material. Depending on preferred nomenclature and definitional nuance, one of ordinary skill may similarly refer to the removal of solute into a solvent from solid material as extracting.

[0036] It may be understood by those skilled in the art that treating step time may be highly dependent on particle size, particle size distribution, morphology and physical form of the contaminated feedstock and / or contaminant components. Such understanding may be particularly but not exclusively applicable to embodiments wherein a dissolved contaminant is formed. Accordingly, in one or more exemplary embodiments, the contaminated polyester recovery feedstock includes polyester and contaminant with a particle size no more than 5000 microns in any dimension or no more than 2000 microns in any dimension or no more than 1000 microns in any direction or no more than 500 microns in any dimension. Accordingly, in one or more exemplary embodiments, the contaminated polyester recovery feedstock preferably includes at least one of contaminant and polyester in the form of flakes, shreds, fibers, powders or grindings. While less preferable, the contaminated polyester recovery feedstock may include at least one of contaminant and polyester in the form or densified (material that has been heated, at least partially melted and melded together) or extruded materials.

[0037] In one or more exemplary embodiments, the treating step may be performed at a temperature of from 20°C to 230°C, more preferably from 60°C to 175°C. In one or more exemplary embodiments wherein the contaminated polyester recovery feedstock does not include polyamides, the treating step may be performed at a temperature of 130°C to 220°C, preferably from 130°C to 190°C. In one or more exemplary embodiments, the treating step or a substep thereof may be performed at a temperature of from 155°C to 175°C. In one or more exemplary embodiments, the treating step or a substep thereofmay be performed at a pressure of from 1 bara to 15 bara or from about 1 bara to 8 bara. In one or more exemplary embodiments, the period or time for the treating step may be from 10 minutes to 6 hours or from 20 minutes to 4 hours. In one or more exemplary embodiments, particularly including but not limited to treating steps using a solvent and in which the treating step forms solubilized polyester, the treating step may be performed at a modification mass ratio (MMR) of from about defined as the mass ratio of solvent to polyester present in the contaminated polyester recovery feedstock, of 3 / 1 to 20 / 1 , preferably 4 / 1 to 10 / 1. As used herein, exemplary MMR levels relate primarily to and are described for the purpose of achieving maximum polyester solubilization, and maximum contaminant dye solubilization (in applicable embodiments). Excess solvent may nonetheless be included to for example create additional effects such as fluidity or flowability of the system or to function as a carrier liquid while remaining within the spirit and scope of the invention.

[0038] In an exemplary embodiment wherein the contaminant includes one or more dyes and the solvent includes NMP, the treating step may be performed at a temperature of 20°C to 175°C. In an exemplary embodiment wherein the contaminant includes one or more dyes and the solvent is NMP, the treating step may be performed at a pressure of 1 bara to 15 bara or from about 1 bara to 8 bara, In an exemplary embodiment wherein the contaminant includes one or more dyes and the solvent is NMP, the period or time for the treating step may be 10 minutes to 6 hours or from 20 minutes to 4 hours. In an exemplary embodiment wherein the contaminant includes one or more dyes and the solvent is NMP, the treating step may be performed at an MMR 3 / 1 to 20 / 1 , preferably 4 / 1 to 10 / 1. In an exemplary embodiment wherein the contaminant includes one or more dyes and the solvent includes DMAC (N,N-dimethyl acetamide), the treating step may be performed at a temperature of 20°C to 175°C. In an exemplary embodiment wherein the contaminant includes one or more dyes and the solvent is NMP, the treating step may be performed at a pressure of 1 bara to 15 bara or from about 1 bara to 8 bara, In an exemplary embodiment wherein the contaminant includes one or more dyes and thesolvent is DMAC, the period or time for the treating step may be 10 minutes to 6 hours or from 20 minutes to 4 hours. In an exemplary embodiment wherein the contaminant includes one or more dyes and the solvent is DMAC, the treating step may be performed at an MMR 3 / 1 to 20 / 1 , preferably 4 / 1 to 10 / 1.

[0039] One of ordinary skill may appreciate that, in some cases, the contaminated polyester recovery feedstock may include an unknown or unmeasured amount of contaminant(s). Accordingly, in one or more exemplary embodiments the treating step may be performed at a feedstock-based mass ratio (FMR), defined as the mass ratio of solvent to contaminated polyester recovery feedstock, of from 0.5 / 1 to 5 / 1 or from 1 / 1 to 3 / 1. Though these FMR ranges are preferable, lower FMRs ratios that may produce a very thick and difficult-to-mix material may be successfully processed in the presence of water or aqueous salt solution.

[0040] One will appreciate that identification and selection of variables such as choice and amount of solvent and treating step conditions may vary depending on a number of factors, including without limitation presence or absence of a specific contaminant, amount of contaminant, presence or absence of various contaminant combinations in the feedstock, and the like.

[0041] In at least one exemplary embodiment, the one or more contaminants may include PVC and the at least one solvent may be selected from the group consisting of C3 to C11 , preferably acetone or C5 to C9, ketones; C4 to C10, preferably C5 to C8, alkyl esters; C8 to C12, preferably C8 to C10, aromatic esters; C6 to C12, preferably C6 to C10, aromatics; C7 to 010, preferably C7 to C9, aromatic alkanols; C5 to C8, preferably C5 to C7 secondary and tertiary cyclic amides; 03 to 06, preferably 03 to 05 secondary and tertiary aliphatic amides. In one or more embodiments wherein the at least one contaminant non-polyester comprises PVC, the treating step may include solubilizing PVC. In general, it has been observed that PVC may decompose or partially decompose to produce HOI (which may be soluble in treating step solvent or solvent) and a polyunusaturated PVC backbone. Accordingly, in one or more embodiments wherein the at least one contaminant non-polyester comprisesPVC, the treating step may include decomposing PVC to form HCI and a polyunusaturated PVC backbone. The treating step may further include neutralizing the formed HCI with a neutralizing species to form a neutralized chlorine salt. Neutralizing species may include alkali and alkali earth salts of C1-C8 carboxylic and dicarboxylic acids, exemplified by acetic, propionic, butyric acid sodium, potassium, lithium, calcium, magnesium salts; alkali and alkali earth carbonate and bicarbonate salts, exemplified by sodium, potassium, lithium, calcium, magnesium carbonates and bicarbonates. The neutralizing species may be soluble or insoluble in the solvent. The neutralized chlorine salt may be present in the treating zone product and accordingly may be separated from the treating zone product. In one or more embodiments wherein the at least one contaminant non-polyester comprises PVC, the treating step may include solubilizing the formed polyunsaturated PVC backbone. Suitable solvents for solubilizing the polyunsaturated PVC backbone may include C6 to C12, preferably C6 to C10, aromatics; C6 to C14, preferably C7 to C12, alkanes. Suitable treating step temperatures for solubilizing the polyunsaturated PVC backbone may range from to 150°C to 190°C. In one or more embodiments wherein the at least one contaminant non-polyester comprises PVC, the treating step may include melting the formed polyunsaturated PVC backbone. In one or more embodiments wherein the at least one contaminant non-polyester comprises PVC, the treating step may include solubilizing and decomposing PVC. In one or more embodiments wherein the at least one contaminant non-polyester comprises PVC, the treating step may include solubilizing PVC.

[0042] In at least one exemplary embodiment, the one or more contaminants may include dyes and the at least one solvent may be selected from the group consisting of aliphatic C3-C6, preferably C3-C5 secondary and tertiary amides, for example Dimethylacetamide (DMAC) and dimethylpropionamide; C5-C8, preferably C5-C7 secondary and tertiary lactams and similar cyclic amides, for example N-Methyl-2-pyrrolidone (NMP) and N-Butyl-2-pyrrolidone; C3 to C11 ketones, preferably C3-C9 ketones; C1 to C10, preferably C1 to C6 alkanolsand glycols; C6 to C14, preferably C7-C12 alkanes; 08 to 012, preferably 08 to C10 aromatic esters; 04 to C10, preferably 04 to 06 Glycol ether / esters; 04 to 010 alkyl esters, preferably 05 to 08 esters; 06 to C12 aromatics, preferably 06 to C10 aromatics; 07 to C10, preferably, 07 to 09, aromatic alcohols; 02 to 06 carboxylic acids, preferably 02 to 04 carboxylic acids; 02 to 04 carboxylic acids or C1 to 04 alkanols with soluble salts of Group HA cations with anions selected from chloride, bromide, acetate, propionate, lactate, trifluoracetate, triflate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, chloroacetate wherein said salt is soluble in said solvent at least at a 0.25M concentration, preferably 02 to 03 carboxylic acids with Ca and Mg salts of chloride, acetate, propionate, lactate, trifluoroacetate, triflate, nitrate; C1 to 010 alkanols, preferably 04 to 08 alkanols; C1 to 03 alkanols with soluble salts of Group HA cations with anions selected from chloride, bromide, acetate, propionate, lactate, trifluoracetate, triflate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, chloroacetate wherein said salt is soluble in said solvent at least at a 0.25M concentration, preferably C1 to 02 alkanols with Ca and Mg salts of chloride, acetate, propionate, lactate, trifluoroacetate, triflate, nitrate; and combinations thereof.

[0043] In at least one exemplary embodiment, the one or more contaminants may include polyolefins and the at least one solvent may be selected from the group consisting of 05 to C11 ketones, preferably 05-09 ketones; 06 to 012 aromatics, preferably 06 to C10 aromatics; 06 to 014 alkanes, preferably 07 to C12 alkanes; 04 to C10, preferably 05 to 08, alkyl esters; 08 to C12, preferably 08 to C10, aromatic esters; and combinations thereof. It has been observed that polyolefins may be insoluble under some treating step conditions but may melt under some treating step conditions. Accordingly, in one or more embodiments, the at least one contaminant non-polyester may include polyolefin and the treating step may include melting the polyolefin to form a polyolefin melt in said treating zone product. In one or more embodiments, the treating zone product may include a polyolefin melt phase and a solvent phase and the method may further include separating the polyolefin melt phase fromthe solvent phase. In one or more embodiments, the polyolefin melt phase floats on the solvent phase, with the at least one solvent selected from a group consisting of one or more of aliphatic C3-C6, preferably C3-C5 secondary and tertiary amides; C5-C8, preferably C5-C7 secondary and tertiary lactams and similar cyclic amides; C1 to C10, preferably C1 to 06 alkanols and glycols; C4 to C10, preferably 04 to 06 Glycol ether / esters; 07 to C10, preferably, 07 to 09, aromatic alcohols; 02 to 06 carboxylic acids, preferably 02 to 04 carboxylic acids; 02 to 04 carboxylic acids or 01 to 04 alkanols with soluble salts of Group HA cations with anions selected from chloride, bromide, acetate, propionate, lactate, trifluoracetate, triflate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, chloroacetate wherein said salt is soluble in said solvent at least at a 0.25M concentration. The separating step may include cooling the treating zone product to solidify or precipitate the polyolefin melt. In one or more embodiments, the at least one contaminant non-polyester may include polyolefin and the treating step may include solubilizing the polyolefin. In one or more embodiments, the at least one contaminant non-polyester may include polyolefin and the treating step may include melting and solubilizing the polyolefin.

[0044] In at least one exemplary embodiment, the one or more contaminants may include polyamides and the at least one solvent may be selected from the group consisting of C8 to C12, preferably C8 to C10, aromatic esters; C2 to C4 carboxylic acids or C1 to C4, preferably C1 to C2 alcohols, with soluble salts of Group IIA cations with anions selected from chloride, bromide, acetate, propionate, lactate, trifluoracetate, triflate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, chloroacetate wherein said salt is soluble in said solvent at least at a 0.25M concentration, preferably C2 to C3 carboxylic acids with Ca and Mg salts of chloride, acetate, propionate, lactate, trifluoroacetate, triflate and nitrate; C1 to C2 alkanols with soluble salts of Group IIA cations with anions selected from chloride, bromide, acetate, propionate, lactate, trifluoracetate, triflate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, chloroacetate wherein said salt is soluble in saidsolvent at least at a 0.25M concentration, preferably C1 to C2 alkanols with Ca and Mg salts of chloride, acetate, propionate, lactate, trifluoroacetate, triflate and nitrate; alkanes, and combinations thereof.

[0045] In at least one exemplary embodiment, the one or more contaminants may include elastanes and the at least one solvent may be selected from the group consisting of C3 to C11 , preferably C3 to 09, ketones; C8 to C12, preferably 08 to 010, aromatic esters; 05 to C8, preferably 05 to 07 secondary and tertiary cyclic amides; 03 to 06, preferably 03 to 05 secondary and tertiary aliphatic amides; 02 to 04 carboxylic acids with soluble salts of Group HA cations with anions selected from chloride, bromide, acetate, propionate, lactate, trifluoracetate, triflate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, chloroacetate wherein said salt is soluble in said solvent at least at a 0.25M concentration, preferably 02 to 03 carboxylic acids with Ca and Mg salts of chloride, acetate, propionate, lactate, trifluoroacetate, triflate and nitrate; C1 to 02 alkanols with soluble salts of Group HA cations with anions selected from chloride, bromide, acetate, propionate, lactate, trifluoracetate, triflate, nitrate, phosphate, hydrogen phosphate, dihydrogen phosphate, sulfate, chloroacetate wherein said salt is soluble in said solvent at least at a 0.25M concentration, preferably 01 to 02 alkanols with Ca and Mg salts of chloride, acetate, propionate, lactate, trifluoroacetate, triflate and nitrate; alkanes, and combinations thereof.

[0046] In at least one exemplary embodiment, the one or more contaminants may include polycarbonates and the at least one solvent may be selected from the group consisting of 03 to 011 , preferably 03 to 09, ketones; 04 to C10, preferably 05 to 08, alkyl esters; 06 to 012, preferably 06 to 010, aromatics; 05 to 08, preferably 05 to 07 secondary and tertiary cyclic amides; 03 to 06, preferably 03 to 05 secondary and tertiary aliphatic amides; and combinations thereof.

[0047] In at least one exemplary embodiment, the one or more contaminants may include silicones and the at least one solvent may be selected from thegroup consisting of 08 to 012, preferably C8 to 010, aromatic esters, and combinations thereof.

[0048] In at least one exemplary embodiment, the one or more contaminants may include adhesives and the at least one solvent may be selected from the group consisting of C8 to C12, preferably C8 to 010, aromatic esters; C5 to C8, preferably C5 to C7 secondary and tertiary cyclic amides; C3 to C6, preferably 03 to 05 secondary and tertiary aliphatic amides, and combinations thereof. In one or more exemplary embodiments, the at least one solvent may include a solvent that dissolves an adhesive that facilitates separation of the PET and a contaminant. In one non-limiting example, adding a solvent may include a solvent that dissolves an ethylene vinyl alcohol adhesive coupling polyolefin to PET layers of a composite material.

[0049] In at least one exemplary embodiment, the contaminated polyester recovery feedstock may include as contaminants one or more of cotton, cellulose and regenerated cellulose (collectively referred to here as cellulosics). In such embodiments, the cellulosics are typically unsolubilized in the treating step and therefore may be described as insoluble contaminants in the context of the treating step. Data indicating such a result is exemplified in Table A-8 below. Nonetheless, cellulosics may be modified during the treating step so as to enhance their separation in a separating step of the present method. For example, cellulosics may be swelled during the treating step or may be reacted with a reactant such as a carboxylic acid anhydride during the treating step to form a cellulosic derivative such as a cellulose ester which may or may not be solubilized under treating step conditions. Accordingly, the treating step may include swelling cellulosic contaminant or reacting cellulosic contaminant to form a cellulosic derivative.

[0050] Tables A-1 through A-9 below present data generated on feedstocks that included various contaminants and solvents and employing various treating step conditions. The data represents testing for embodiments wherein the solvent solubilized the contaminant under the indicated treating step temperatures or temperature ranges. Accordingly, contaminant solubilizationmay be presumed to have occurred in the data in the Tables (and is occasionally but not exclusively indicated with an “S”) except as expressly indicated otherwise (such as the label N / A, indicating not applicable). Further, as contaminant solubilization without polyester solubilization was a primary criterion of the testing reflected in the Tables, testing time period and solvent concentration was varied in some experimental runs to determine whether solubilization could be achieved. For some experimental runs, preliminary experiments were performed using only contaminants in various physical forms such as fibers or fabrics (i.e. , without the presence of polyester) to generally define suitably effective solvents and treating step conditions for select contaminants prior to treating a polyester-containing feedstock including those contaminants. Similarly, experiments were performed using only polyester (i.e., without the presence of contaminants) to generally define suitably effective solvents and treating step conditions for polyester, with the data set forth in T able A-10, and then subsequently tested with PET / contaminant mixtures, both contrived and commercially available feedstocks, to validate specified treating step conditions. Treating step pressures were selected to maintain the carrier liquid / solvent in the liquid phase. As a non-limiting example of reading the Table data, one of ordinary skill will appreciate that dye contaminants were found to be solubilized by multiple C3-C11 ketone solvents using a treating step temperature range of 100°C -180°C, with a temperature range of 140°C to 170°C and a C3-C9 ketone solvent being preferred.

[0051] In one non-limiting example referencing the data presented in the Tables below, a treating step of the method of the present invention may include treating a feedstock of polyester and elastanes with a C5-C8 secondary / tertiary cyclic amide solvent at a temperature of 180°C, with the below data evidencing that both the elastane and the polyester are solubilized in the treating step. As another non-limiting example, a treating step of the method of the present invention may include treating feedstock of dye and polyester with a C8-C12 aromatic ester with a first substep at a temperature of 150°C (at which the dye solubilizes) and then a second substep with the same solvent at a temperatureof 200°C (at which the polyester solubilizes). In yet another non-limiting example, a treating step of the method of the present invention may include treating a feedstock including polyester and polycarbonate with a first substep using a C3-C11 ketone as solvent at a temperature of 130°C (in which the polycarbonate solubilizes) and a second substep using a C8-C12 aromatic ester as solvent at a temperature of 220°C (in which the polyester solubilizes).TABLE A-1 - DYESTABLE A-1 - DYESF = Float, D= solubilizes Cl-depleted backbone from PVC, Cl-depletion accelerated at higher T's above 150C# must contain naphthalene ringR = reacts, begins to depolymerize PET even without catalystTABLE A-2 - SILICONESTABLE A-2 - SILICONESTABLE A-3 - PVCTABLE A-3 - PVC* S= solubilizes F = Float, D= solubilizes Cl-depleted backbone, Cl- depletion accelerated at higher T's above 150C# must contain naphthalene ringR = reacts, begins to depolymerize PET even without catalystTABLE A-4 - POLYCARBONATETABLE A-5 - POLYOLEFINTABLE A-5 - POLYOLEFIN* S= solubilizes F = Float, D= solubilizes Cl-depleted backbone, Cl- depletion accelerated at higher T's above 150C# must contain naphthalene ringR = reacts, begins to depolymerize PET even without catalystTABLE A-6 - ADHESIVESTABLE A-7 - ELASTANESTABLE A-7 - ELASTANESTABLE A-8 - CELLULOSICSTABLE A-8 - CELLULOSICSTABLE A-9 - POLYAMIDETABLE A-9 - POLYAMIDETABLE A-10 - POLYESTER* S= solubilizes F = Float, D= solubilizes Cl-depleted backbone, Cl-depletion accelerated at higher T's above 150C# must contain naphthalene ringR = reacts, begins to depolymerize PET even without catalyst

[0052] An exception to solubilization was observed and is listed under the “polyolefins” category of Table A-5 and is identified with a letter “F” to indicate that the contaminant polyolefin melted and formed a floating melt phase component in a two-phase treating step product that included a separate solvent phase. Another exception to solubilization was observed and is listed under the “PVC” category of Table A-3 and is identified with a letter “D” to indicate that the contaminant PVC decomposed as evidenced by formation of a black residue and the detectable generation of HCI. Finally, reaction of the polyester, primarily in the form of depolymerization, was observed in certain relatively higher-temperature runs at about 190°C and is identified in Table A with an “R”.

[0053] In at least one exemplary embodiment, the method may further include a step of reducing the average particle size of the feedstock prior to the treating step. Suitable particle size reducing methods, and related systems and equipment, are known in the art and are exemplified without limitation by grinding, tearing, crushing, comminuting, shredding, pulverizing, cryogrinding, chopping, shearing, sonically grinding, and the like. Moreover, the step of reducing the average particle size of the feedstock reduction step may be preceded by contacting the treating the feedstock with particle size reduction facilitator such as a swelling agent in embodiments wherein such treatment may facilitate particle size reduction.

[0054] While treating step in general includes treating contaminant with solvent to form solubilized contaminant, the specific conditions of the treating step may be varied so as to create different or multiple modifications to a specified contaminant. Accordingly, a modified contaminant may include multiple modifications or first and second modifications in some embodiments. Further, a modified contaminant may include a first modification under a first set of treating step conditions and a second modification, or a first and second or multiple modifications, under a second set of treating step conditions. In one non-limiting example, contaminants (for example polyolefins) may be bothsolubilized and melted in a treating step to form solubilized, melted contaminant. In such embodiments, the solubilized contaminant may form a single phase with the carrier liquid present in the treating zone product. Depending on for example treating step temperature, a contaminant such as polyolefin may be melted but not solubilized and thereby form melted contaminant. In such embodiments, the modified contaminant may form a phase separate from the carrier liquid present in the treating zone product. In another non-limiting example, contaminants (for example PVC) may be both solubilized and decomposed in a treating step to form solubilized, decomposed contaminant. Depending on for example treating step temperature, a contaminant such as PVC may be decomposed but not solubilized to form decomposed contaminant.

[0055] In at least one exemplary embodiment, the polyester recovery feedstock includes a composite material comprising a polyester component and a contaminant component coupled together. In general, the phrase “composite material” may include any unitary material wherein a polyester and a contaminant are both present. Non-limiting examples of composite materials may include agglomerates; laminates; multilayer constructions such as films, flooring and the like; coated substrates; materials that may include multiple polymer components coupled for example by heat bonding or adhesive; multicomponent or blended fiber fabrics and textiles, and similar constructions. In one non-limiting example, a polyester recovery feedstock may have agglomerated and formed agglomerates over time, for example by exposure to increased temperature or other storage conditions such as humidity. Further, a polyester recovery feedstock may have been purposefully processed to improve handling or transport, with such processing causing formation of agglomerates. One of ordinary skill may appreciate that, for purposes of achieving the numerous benefits of the present invention, including effectiveness, productivity, processing speed and target product yields, presence orformation of agglomerates in the feedstock prior to the treating step should be avoided or limited. To the extent purposeful processing generatesagglomerates, the benefits of such processing should be weighed against any negative impact on the method of the present invention. In general, the presence of agglomerates may be reduced or eliminated by particle size reduction techniques described herein.

[0056] In at least one exemplary embodiment, the method of the present invention may include mechanically separating the polyester component and the contaminant component of a composite material. In at least one exemplary embodiment, the treating step of the method of the present invention may include mechanically separating the polyester component and the contaminant component of a composite material. In at least one exemplary embodiment, method of the present invention may include applying a friction force to mechanically separate any polyester component and contaminant component of a composite material that remains coupled together after the treating step. In at least one exemplary embodiment, method of the present invention may include applying a friction force to mechanically separate undissolved polyester and swelled contaminant of a composite material that remains coupled together after the treating step. Non-limiting examples of applying a friction force may include high shear mixing, abrading, scraping, grinding and the like. In at least one exemplary embodiment, the step of applying a friction force is preceded by a step of swelling one or more of the contaminant components and the polyester of a composite material. Swelling affects the dimensional stability of the contaminant / PET interface, facilitating frictional separation, which may create sub-particles of swelled contaminant and particles enriched in PET content from particles of the original composite material. Swelling of polyester may be achieved for example by hydrogenated terphenyls, alkyl naphthalenes, or phenyl ethers.

[0057] In at least one exemplary embodiment, the step of applying a friction includes creating swelled contaminant agglomerates or sub-particles, as such agglomerates or sub-particles which facilitate further processing of the modified contaminant, for example to recover solvent.

[0058] One will appreciate that, for contaminants that include composite materials, the treating step perse may in some embodiments facilitate or effect partial or total separation of the polyester component and the contaminant component of a composite material contaminant. Accordingly, in at least one exemplary embodiment, the method of the present invention may include a treating step that includes separating the polyester component and the contaminant component of a composite material.

[0059] The method of the present invention may include separating insoluble contaminant from the treating zone product, for example in a separating zone 30, to form a solubilized polyester recovery intermediate 32 that includes solubilized polyester. The solubilized polyester recovery intermediate 32 may further include at least one solubilized contaminant. In some embodiments, the separating step may include separating the insoluble contaminant from carrier liquid or solvent. In at least one exemplary embodiment, the method may include a separating step that may include filtering insoluble contaminant from a polyester recovery intermediate including solvent, solubilized contaminant dye, solubilized polyester and insoluble contaminant. The separating zone 30 for separating step may include one or more processes, devices or systems for solid / liquid separation, such as for example belt filters, rotary filters, candle filters, bag filters, plate and frame filters, screen / scroll, pusher centrifuges, peeler centrifuges, inverting filter centrifuges, sliding discharge centrifuges, pendulum centrifuges, sedimentation centrifuges, hydrocyclones, sedimentation vessels. Said solid / liquid separation devices may be operated under vacuum or pressurized conditions, in batch or continuous mode, as a single unit, or in one or more units in series or parallel format. For some exemplary embodiments, the separating step may be performed or the separating zone 30 may be operated at temperature and pressure conditions generally similar to the treating zone, i.e. , 130°C to 220°C, preferably 150°C to 190°C, at a pressure sufficient to maintain solubilized and solubilized components in their existing state, typically about 1 bara to 15 bara, more preferably about 1 bara to 8 bara. In embodiments wherein thecontaminated polyester recovery feedstock includes dyed materials such as one or more of dyed polyester and dyed contaminant, the dye contaminant may be leached from the dyed material and solubilized in the treating step (a). Accordingly, the treating step may in some embodiments include leaching contaminant dye from such dyed materials. In at least one or more embodiments, the separating step is performed or the separating zone is operated under conditions in which the solubilized polyester remains soluble.

[0060] In one or more exemplary embodiments, at least one contaminant and the polyester are substantially solubilized concurrently or as a single step in the treating step (a). In such embodiments, the treating step is performed at conditions at which at least one contaminant and polyester are solubilized in the treating step. As described above, the treating step product from the treating step may include insoluble contaminants which may be separated from the treating zone product in a separating step or in some embodiments during the treating step.

[0061] In one or more embodiments, contaminant and polyester are substantially solubilized sequentially or in multiple substeps or in sequential substeps in the treating step (a). In such embodiments, the treating step (a) may include substep (a1) treating the contaminated polyester recovery feedstock with a solvent under conditions in which at least one of said one or more contaminants is solubilized and said polyester is substantially insoluble, forming a treating zone product intermediate comprising said one or more solubilized contaminants and unsolubilized polyester; substep (a2) removing said one or more solubilized contaminants from said treating zone product intermediate; and substep (a3) treating said treating zone product intermediate with a solvent under conditions in which said unsolubilized polyester is solubilized, forming treating zone product comprising solubilized polyester. Insofar as the treating zone product intermediate may further include insoluble contaminants, the method may in some embodiments further include removing insoluble contaminants from the treating zone product intermediate. In one or more exemplary embodiments, the solvent of substep (a1) and said solvent ofsubstep (a3) may be the same solvent (from the standpoint of molecular structure). In one or more exemplary embodiments, substep (a3) may be performed at a temperature higher than the temperature of substep (a1 ). In one or more exemplary embodiments, the temperature of substep (a1 ) may be no more than 130°C and the temperature of substep (a3) may be at least 160°C. In embodiments wherein the contaminated polyester recovery feedstock includes dyed materials such as one or more of dyed polyester and dyed contaminant , the dye contaminant may be leached from the dyed material and solubilized in substep (a1 ). Accordingly, substep (a1 ) may in some embodiments include leaching contaminant dye from such dyed materials. In one or more exemplary embodiments, the solvent of substep (a1) and said solvent of substep (a3) may be different solvents (from the standpoint of molecular structure). In one or more exemplary embodiments, the solvent may include or consist of or consist essentially of N-Methyl-2-pyrrolidone. In one or more exemplary embodiments, the method may further include a step of adding an additional amount of solvent after substep (a2) and prior to or concurrent with substep (a3). In one or more exemplary embodiments, the at least one contaminant may include one or more of cotton, olefin, elastane and polyamide. In one or more exemplary embodiments, the contaminated polyester recovery feedstock may include a polyester blend textile product that may include polyester fibers and one or more of cotton, olefin, spandex and polyamide fibers. In one or more exemplary embodiments, the method may further include a step of removing solubilized contaminant dye from the treating zone product.

[0062] In some embodiments, the treating step (a) may include substep (a1 ) treating said contaminated polyester recovery feedstock with at least one solvent under conditions in which said polyester is solubilized, forming a treating zone product intermediate comprising solubilized polyester and one or more insoluble contaminants; and substep (a2) removing at least some of said one or more insoluble contaminants from said treating zone product intermediate. The method of the present invention may include a step of separating insoluble contaminant from said treating zone product (or inapplicable embodiments a treating zone product intermediate) in a separating zone to form a solubilized polyester recovery product that includes solubilized polyester and optionally one or more solubilized contaminant. In brief, the separating step and the separating zone involve separation of insoluble contaminant from the treating zone product. As discussed elsewhere, insoluble contaminants may include without limitation typically solid materials such as cotton, cellulose and regenerated cellulose (rayon), collectively cellulosics; carbon black; metals, exemplified by aluminum, steel, copper artifacts, such as wires, pop tops, screws, nails, textile detritus, including zippers, snaps, buttons, rivets, and the like; inorganics exemplified by TiO2, silicon dioxide, clays, rocks, gravel, pebbles and the like. Such insoluble contaminants may be separated in the separating step by known solid / liquid separation techniques such as filtering, sedimentation, centrifugation and the like. In one or more embodiments, such as embodiments that include polyolefins exemplified by polypropylene and polyethylenes such as LDPE and HDPE as a contaminant, the treating zone product may include polyolefin melt or may include a polyolefin melt phase and a solvent phase, and the separating step may include separating the polyolefin melt phase from said solvent phase. In embodiments wherein PVC is a contaminant and the treating step may include decomposing PVC to form HCI and a decomposed polyunsaturated PVC backbone and neutralizing the HCI with a neutralizing species to form a neutralized chloride salt in said treating zone product, the separating step may include separating one or both of the neutralized chloride salt and the decomposed polyunsaturated PVC backbone from the treating zone product. In one or more embodiments, the method of the present invention may include solubilizing the polyunsaturated PVC backbone, for example as a component of the separating step or the treating step. In one or more embodiments, the method of the present invention may include filtering out the neutralized chloride salt and polyunsaturated PVC backbone (if insoluble in the contaminant solvent), for example as a component of the separating step or the treating step. In another embodiment wherein one or both of the polyunsaturated PVC backbone orneutralized chloride salt is solubilized, said contaminants may be removed from the polyester in a polyester precipitation step or a polyester solids washing step.

[0063] In one or more exemplary embodiments, the separating step may include filtering insoluble contaminant from the treating zone product to produce a recovery product that includes solubilized polyester. The separated insoluble contaminant may be referred to as contaminant filtrate and may be further processed for recovery or re-use, including but not limited to washing with a wash solution.

[0064] As depicted in Figures 1 through 4, the separating step may be performed in a separating zone 30 which receives product 4 from treating zone 10 and in which one or more components of treating zone product 4 are separated from each other. The separating zone 30 for separating step may include one or more processes, devices or systems for solid / liquid separation, such as for example belt filters, rotary filters, candle filters, bag filters, plate and frame filters, screen / scroll, pusher centrifuges, peeler centrifuges, inverting filter centrifuges, sliding discharge centrifuges, pendulum centrifuges, sedimentation centrifuges, hydrocyclones, sedimentation vessels. Said solid / liquid separation devices may be operated under vacuum or pressurized conditions, in batch or continuous mode, as a single unit, or in one or more units in series or parallel format.

[0065] In at least one exemplary embodiment and as depicted in Figures 1- 4, the separating step may be performed in separating zone 30 and may form (i) a polyester recovery intermediate 32 that may include solubilized polyester, solubilized contaminant and one or more solvents and ((ii) insoluble contaminant stream 31 that includes insoluble contaminant and one or more solvents which may act as a carrier liquid. In embodiments wherein the separating step includes filtering, the stream 31 may be labeled insoluble contaminant filtrate 31. In at least one exemplary embodiment, one or both of the insoluble contaminant stream 31 and the solubilized polyester recovery product 32 may include carrier liquid that may include solvent. In embodiments with PVC contaminant, neutralizing species for PVC HCI decomposition productmay be added at stream 33. Stream 33 may alternatively be a stream for adding contaminant recovery enhancement agent or anti-solvent as described elsewhere herein.

[0066] One of ordinary skill will be appreciate that, in some embodiments, the treating zone product may include non-polymeric contaminants, such as for example inorganic contaminants, that may not be readily solubilized by the solvent(s) utilized in the present method under any treating step conditions. The separating step may in one or more exemplary embodiments therefore further include separating non-polymeric insoluble contaminant from the treating zone product. To the extent such non-polymeric insoluble contaminants may have a numeric difference in density between them and polyester, this separating step may include classifying non-polymeric insoluble contaminant by density differential separation.

[0067] Insoluble contaminant stream 31 may include, for example, one or more solvents and insoluble contaminant which may have value or use. Accordingly, in at least one exemplary embodiment, the method of the present invention may optionally include recovering at least one insoluble contaminant and optionally one or more solvents from the insoluble contaminant stream 31 . This insoluble contaminant recovering step may be carried out either batch- wise or continuously. With reference to Figures 3 and 4, the step of recovering insoluble contaminant may be performed in an insoluble contaminant recovering zone 50. Insoluble contaminant recovering zone 50 may include one or more processes, systems and devices to extract or otherwise separate solvent from insoluble contaminant. Exemplary unit operations that may be performed in an insoluble contaminant recovering zone 50 include known solidliquid separation methods listed elsewhere herein and include dewatering techniques such as centrifugation, pressing, augering, drying, evaporation, adding water as a contaminant recovery enhancement agent, combined with distilling via azeotropic distillation, distillation, decantation, adsorption, flocculation, flotation and absorption. Said recovery methods may be accomplished batchwise or continuously with one or more method occurringsequentially. The step of recovering insoluble contaminant may include adding an insoluble contaminant recovery enhancement agent or anti-solvent, depicted as stream 52. Exemplary agents include without limitation water, floating / collecting agents, filter aids, flocculating agents, adsorbents, drying gases and absorbents. In one non-limiting example, the insoluble contaminant recovering step may include drying stream 31 in a dryer to form solvent recovery stream 51 and a dry solids stream 55. In another non-limiting example, the insoluble contaminant recovering step may include washing stream 31 with an insoluble contaminant recovery enhancement agent that includes a low boiling solvent 52 drying insoluble contaminants to form a dry solids stream 55 that includes dry contaminants; separating (such as by distillation) the insoluble contaminant recovery enhancement agent from the at least one treating step solvent; recovering (and optionally recycling) the low boiling solvent; and recycling the at least one treating step solvent as shown in the Figures at 51. In yet another non-limiting example, the insoluble contaminant recovering step may include mixing insoluble contaminant stream 31 with water; azeotropically distilling out the at least one treating solvent; decanting and returning treating zone solvent as shown in the Figures at 51 ; adding flocculant to the insoluble contaminants / water mixture; and filtering out solids.

[0068] Recovering step in insoluble contaminant recovering zone 50 may form solvent recovery stream 51 that includes one or more solvents and insoluble contaminant recovery stream 55 which may include insoluble contaminant. At least one exemplary embodiment, solvent recovery stream 51 may be recycled to the treating step in treating zone 10. Accordingly, in at least one exemplary embodiment, the method of the present invention may include recovering one or more of the solvent and contaminant. Further, in one or more exemplary embodiments, the method of the present invention may include recycling solvent to the treating step.

[0069] Polyester recovery product intermediate 32 includes solubilized polyester and may include, for example, one or more solvents and solubilizedcontaminants which may have value or use. Accordingly, in at least one exemplary embodiment, the method of the present invention includes recovering the solubilized polyester and optionally one or more solvents or one or more contaminants from the polyester recovery intermediate 32. With reference to Figures 3 and 4, the step of recovering polyester contaminant may be performed in a solubilized polyester recovering zone 70. This solubilized polyester recovering step may be carried out either batch-wise or continuously. Solubilized polyester recovering zone 70 may include one or more processes, systems and devices to extract or otherwise separate one or more of the components of in polyester recovery intermediate 32. Recovering step in recovering zone 70 may in one or more embodiments form solvent recovery stream 71 that includes one or more solvents; solubilized contaminant recovery stream 75 which may include contaminant, and a polyester recovery product 72. At least one exemplary embodiment, solvent recovery stream 71 may be recycled to the treating step in treating zone 10. Accordingly, in at least one exemplary embodiment, the method of the present invention may include recovering one or more of solvent and contaminant. Further, in one or more exemplary embodiments, the method of the present invention may include recycling solvent to the treating step.

[0070] It should be understood that zone 70 is labeled a “solubilized” polyester recovering zone to represent that the feed to the zone, namely solubilized polyester recovery intermediate 32, includes solubilized polyester. Further, it should be understood that polyester recovery product 72, while including target polyester as general matter, may or may not include solubilized polyester, Accordingly, in one or more embodiments, polyester recovery product 72 may include solubilized polyester. In one or more embodiments, polyester recovering zone 70 may include functionality got changing the physical form of the polyester. Accordingly, in one or more embodiments, polyester recovery product 72 may include polyester solids (solidified polyester), for example a polyester precipitate, particulate or crystalline material, which may be formed when solubilized polyester is converted to asolid form in polyester recovering zone 70. In one or more embodiments, polyester recovery product 72 may include a polyester melt or slurried polyester solids. The recovering step may therefore include in some embodiments precipitating or crystalizing solubilized polyester, such as by at least one of lowering the temperature of or adding an anti-solvent. Generally, methods for the recovering step that include solidifying or precipitating or crystallizing solubilized polyester to form polyester solids may involve one of several methods known in the art to assist in, or result in, precipitation or crystallization of solubilized material. Non-limiting examples include temperature of the stream, for example by controlled indirect cooling via heat exchange, to reduce the solubility of the solubilized polyester; controlled direct cooling, i.e., evaporative cooling, of the solubilized polyester by boiling and removal of the solvent or another component added as an evaporative cooling agent; concentration of solubilized polyester via distillation, evaporation or other vaporliquid equilibrium-based separation method, removing at least a part of the solvent to increase the level of supersaturation of the solubilized polyester; addition of or treatment with a recovery enhancement agent such as an antisolvent component for the solubilized polyester; evaporative drying of the solubilized polyester such as by spray drying; or combinations thereof.

[0071] Selection of an appropriate polyester antisolvent is dependent on the identity of the solvent used for dissolution of the polyester, but said anti-solvent is preferably fully miscible with a polyester target dissolution solvent. In one or more embodiments wherein the dissolution solvent is a cyclic or aliphatic amine, an aromatic, or an aromatic ester exemplary antisolvents are C1 to C6 alkanols or glycols, C3 to C7 ketones, C4 to C6 aliphatic esters, C6 to C9 aromatics, and C4 to C6 glycol ethers or esters. Typical ratio of anti-solvent to dissolution solvent are 0.5 / 1 to 6 / 1 . Antisolvents include species miscible with a target polyester dissolution solvent such as C3-C6 ketones, exemplified by acetone, MEK, MPK, MIPK, MIBK; C1-C4 alkanols, exemplified by methanol, ethanol, propanols, butanols; C6-C9 aromatics, exemplified by benzene,toluene, xylenes and isomers, mesitylene and isomers; C2 to C8 glycols, exemplified by EG, DEG, TEG, CHDM; water; and mixtures thereof.

[0072] The recovering step may be performed at a temperature of from 0°C to 90°C, preferably from 20°C to 70°C. A polyester precipitation step to form polyester solids may be accomplished in a temperature range of 10°C to 110°C.

[0073] Temperature adjustment in recovering step may be achieved by direct contact cooling (mixing hot and cold streams to achieve desired T range by dilution), evaporative cooling (adjusting pressure to achieve boiling of solvent at desired temperature range), or indirect heat exchange via circulation through a heat exchanger). Turbulent flow at mixing points is typically desired, with turbulence induced by static mixing, impellers, homogenizers, impinging jets of liquids and the like. Precipitation rapid cooling for example by mixing the solubilized product with cold solvent (i. e. , the same solvent molecular identity used in the treating step.

[0074] In one or more embodiments, the step of recovering the solubilized polyester may include treating the solubilized polyester with a polyester recovery enhancement agent, such as an anti-solvent, shown in the Figures as added to polyester recovery zone 70 via recovery enhancement agent stream 73, The polyester recovery enhancement agent may include any materials that may enhance or increase the yield or purity of recovered contaminant and / or recovered solvent from the recovering step. In one or more exemplary embodiments, the polyester recovery enhancement agent has low or essentially no solubility for the contaminant at the recovering step conditions. In one or more exemplary embodiments, the polyester recovery enhancement agent may be miscible with the solvent and / or may modify the solubility characteristics of the solvent by reducing the solubility of the polyester therein. The effectiveness of the polyester recovery modifying agent may be enhanced at higher concentrations relative to the solvent. In at least one exemplary embodiment, the polyester recovery enhancement agent has a boiling point higher than the solvent or forms a minimum boiling azeotrope with the solvent.

[0075] In one or more embodiments, contaminant recovery stream 75 includes solubilized contaminant. In at least one exemplary embodiment, the method of the present invention may further include a step of recovering solubilized contaminant, such as for example by in some embodiments converting solubilized contaminant to a solid form (solidified contaminant) by for example solidifying by cooling, precipitating or crystallizing solubilized contaminant. It may be necessary to concentrate the solubilized contaminant prior to ultimate disposal. Said concentration step may be accomplished by methods know in the art such as distillation, azeotropic distillation with water, evaporation, extraction, or combinations therein. The contaminants may also be recovered as a concentrated liquid rather than a solid.

[0076] As depicted in Figures 3 and 4, the step of recovering solubilized contaminant may be performed in a solubilized contaminant recovering zone 80. In one or more exemplary embodiments, the solidified contaminant or recovered contaminant solids as shown in Figures at 85, may be removed from the contaminant recovery stream 75 via solid-liquid separation methods known in the art, such as filtration, centrifugation, hydrocyclonization, sedimentation, and the like. More generally, methods for the recovering step may involve one of several methods known in the art to assist in, or result in, precipitation or crystallization of the contaminant; controlled indirect cooling via heat exchange of the contaminant solution to reduce the solubility of the contaminant in the contaminant solution; controlled direct cooling, i.e., evaporative cooling, of the contaminant solution by boiling and removal from the contaminant solution of the solvent or another component added as an evaporative cooling agent; concentrating of contaminant via distillation, evaporation or other vapor-liquid equilibrium-based separation method, of at least a part of the solvent to increase the level of supersaturation of the contaminant; adding recovery enhancement agent such as an anti-solvent component for the contaminant; evaporative drying of the contaminant solution, such as by spray drying; or combinations thereof. In one or more exemplary embodiments, for example embodiments where the contaminant includes dye, the step of recoveringcontaminant is performed in the presence of a dye recovery enhancement agent, shown in the Figure as 83, may be added to the solubilized contaminant recovering zone 80, and which in general may include any materials that may enhance or increase the yield or purity of recovered contaminant and / or recovered solvent from the recovering step. In one or more exemplary embodiments, the recovery enhancement agent has low or essentially no solubility for the contaminant at the recovering step conditions. In one or more exemplary embodiments, the contaminant recovery enhancement agent may be miscible with the solvent and / or may modify the solubility characteristics of the solvent by reducing the solubility of the contaminant. The effectiveness of the contaminant recovery modifying agent may be enhanced at higher concentrations relative to the solvent. In at least one exemplary embodiment, the contaminant recovery enhancement agent has a boiling point higher than the solvent or forms a minimum boiling azeotrope with the solvent. In one nonlimiting example, the contaminant recovery enhancement agent may include or consist essentially of or consist of water. In another non-limiting example, the contaminant recovery enhancement agent may include or consist essentially of or consist of ethylene glycol and other glycols such as diethylene glycol.

[0077] In one or more exemplary embodiments, this solubilized contaminant recovering step may include cooling the solubilized contaminant stream 75 to an end contaminant solidifying temperature. In general, an end solidifying temperature is a temperature at which a solubilized contaminant that is in liquid or flowable form such as for example a solution or melt, transitions to a solid, for example by solidification of a melt, precipitation or crystallization. A cooling profile for direct or indirect heat removal may span a temperature range from the dissolution temperature used in the treating zone to an end solidifying temperature at which wherein a precipitating polymer contaminant is not sticky and forms free particles. In one or more exemplary embodiments the end solidifying temperature may be less than 100° or less than 80°C.

[0078] For polyolefin contaminants the end solidifying temperature is typically less than 100°C, preferably less than 80°C or even less than 60°C.When the solvent is an alkane, a preferred recovery method is direct or indirect cooling of the contaminant solution to induce precipitation of the polyolefins. When the solvent is an aromatic, ketone, or ester, a preferred recovery method is addition of water as a contaminant recovery enhancement agent and disti llative removal of the solvent via azeotrope formation with water.

[0079] For PVC contaminants, the end solidifying temperature is typically less than 60°C, more preferably less than 40°C or even less than 30°C and is highly dependent on the amount of solvent present. Preferred recovery methods include spray drying, concentration, with and without direct heat exchange, and adding water as a contaminant recovery enhancement agent, combined with distilling via azeotropic distillation.

[0080] For polyamide and elastane contaminants, the end solidifying temperature is typically less than 80°C, more typically less than 60°C or even less than 40°C. For polyamides and elastanes dissolved in alcoholic or carboxylic acid salt solvent, e.g., acetic acid and a calcium salt, a preferred method of recovery of the contaminant may be a combination of contaminant recovery enhancement agent addition and cooling. The preferred contaminant recovery enhancement agent is water, with a water addition rate of 0.5 / 1 water / solvent weight ratio to 0.05 / 1 weight ratio, more preferably 0.2 / 1 to 0.1 / 1 weight ratio, at an end solidifying temperature of 50°C to 20°C. For polycarbonate, the end solidifying temperature is typically less than 60°C, more preferably less than 40°C or even less than 30°C and is highly dependent on the amount of solvent present. Preferred recovery methods include spray drying, concentration, with and without direct heat exchange, and water as a contaminant recovery enhancement agent or contaminant recovery enhancement agent, combined with azeotropic distillation.

[0081] For cellulose or regenerated cellulose that has been converted to a cellulose ester via contaminant reacting agent in the treating step, the end solidifying temperature is typically less than 60°C, more preferably less than 40°C or even less than 30°C and is highly dependent on the amount of solvent and contaminant reactant present. A preferred recovering step includes addingcontaminant recovery enhancement agent or anti-solvent, wherein the contaminant recovery enhancement agent or anti-solvent is water or a C1 to C3 alkanol.

[0082] Dyes may be recovered from contaminant recovery stream 75 via concentration, spray drying, or dye recovery enhancement agent addition to stream 75 with azeotropic distillation of the solvent. A recovering step for dyes is typically carried out at temperatures lower than 150°C, with the corresponding pressure level to allow boiling of the solvent and contaminant recovery enhancement agent if present.

[0083] As discussed previously, the separating step may form a solubilized polyester recovery intermediate, shown at 32, that includes solubilized polyester. For embodiments that include recovering solubilized contaminant for example in in recovering zone 70, a polyester recovery product 72 that includes target polyester may be formed. For embodiments that do not include recovering solubilized contaminant for example in in recovering zone 70, polyester recovery intermediate 32 that may include target polyester is formed. In one or more exemplary embodiments or aspects, the polyester recovery intermediate 32 or the polyester recovery product 72, as depicted in Figures 2 and 4 respectively, may serve as a feed for a target polyester modifying step which for example may be performed in a target polyester modifying zone 100 - and therefore each of polyester recovery intermediate 32 and polyester recovery product 72 may be referred to as a feedstock depending on embodiment. Accordingly, in some embodiments, the method of the present invention may further include in some embodiments a step (d) of modifying the target polyester. Non-limiting examples of modifying, described in more detail below, may include one or more of solidifying (when the feed includes solubilized polyester); washing with a wash solution (when the target polyester is polyester solids); melting to form a polyester melt; depolymerizing; and transesterifying. As shown in Figures 2 and 4, target polyester modifying zone 100 may generate product stream 105 that includes one or more targetproducts and residuals 110 that may include any remaining solvents and contaminants.

[0084] In one or more exemplary embodiments or aspects where the target product is a polyester, the modifying step may include transesterifying target polyester to from a modified polyester or copolyester. In such embodiments, the polyester recovery intermediate 32 and / or the polyester recovery product 72 may serve as a feed for a polyester transesterification process wherein target polyester is transesterified with one or more glycols or polyols with a boiling point higher than ethylene glycol to form product stream 105 that includes as target product target polyester transesterified one or more modified polyester, polyester oligomer, copolyester and the like. Suitable glycols include but are not limited to, diethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, 1 ,2-propanediol, 1 ,3- propanediol, neopentyl glycol, 1 ,4- butanediol, 1 ,5-pentanediol, 1 ,6- hexanediol, p-xylene glycol, 1 ,4- cyclohexanedimethanol, 2,2,4,4-tetramethylcyclobutane-1 ,3-diol, polytetramethylene glycol, isosorbide or mixtures thereof. Suitable polyols include but are not limited to pentaerythritol, trimethylolpropane and trimethylolbutane. Accordingly, in embodiments that include a transesterifying step, streams 32 or 72 may be described as a polyester transesterification feedstock. In such steps the polyester includes one or more polyols or glycols that are substituted with or displaced by one or more substitute polylols or glycols as transesterification agent, with the substitute polyols or glycols substituting or displacing all or part of the initial polyol or glycol to form a modified polyester. In brief, the process of transesterifying is initiated by heating and mixing of the initial polyester, a transesterification catalyst, preferably Ti, Mn, Co, or Zn-based containing catalysts, and one or more substitute polyols or glycols, and is accompanied by simultaneous evaporation or distillation of said initial polyols or glycols to drive the reaction, maintain or increase polyester molecular weight, produce removed polyols and glycols, and to form a modified polyester that may be a polyester. To enable the simultaneous distillation and transesterification, it is necessary that thesubstitute polyols or glycols have either a higher boiling point (lower vapor pressure) than the initial polyols or glycols targeted for removal, or said initial polyols or glycols form a low-boiling azeotrope with an added glycol stripping agent. In one embodiment, the initial polyester comprises ethylene glycol as the initial glycol and is transesterified with the substitute glycol of cis / trans-1 ,4- CHDM, producing ethylene glycol as the removed glycol. In one or more embodiments the removed glycol is ethylene glycol. In one or more embodiments, the modified polyester is a copolyester. In one or more embodiments, the modified polyester is a copolyester comprising 1 ,4-CHDM or 1 ,3-CHDM or combinations therein. In one or more embodiments, the modified polyester is a copolyester comprising neopentyl glycol, 2- Methyl- 1 ,3- Propanediol (hereafter MP diol), 1 ,4-CHDM or 1 ,3-CHDM or combinations therein. In one or more embodiments the added glycol stripping agent forms a low-boiling heterogeneous azeotrope with the removed glycol, such as ethylene glycol. In one or more embodiments the added glycol stripping agent is a C7 to C12 aromatic, a C7 to C14 alkane, a C7 to C11 ketone, wherein said glycol stripping agent. In embodiments that include transesterifying as the target polyester modifying step or as a part thereof, transesterification agent may be added to recovery zone 100 via transestrerification agent stream 103.

[0085] In one or more exemplary embodiments, in particular embodiments where the polyester recovery intermediate includes solubilized polyester, the step of modifying the target polyester may include solidifying solubilized polyester to form polyester solids. In one or more exemplary embodiments, the step of modifying the target polyester may include melting polyester solids to form a target product melt. In one or more exemplary embodiments, the step of modifying the target product may include depolymerizing solubilized polyester, polyester melt or polyester solids.

[0086] In one or more exemplary embodiments wherein the polyester recovery product 72 includes solubilized polyester, the step of modifying the target polyester may include solidifying (for example, precipitating or crystallizing) solubilized polyester in a target product modifying zone 100 toform target product recovery stream 105 that includes as recovered target product(s) polyester solids or washed polyester solids. In such embodiments, the solidifying step may be performed using techniques, methods, anti-solvents and systems described herein for the solidifying step for recovery zone 70. Non-limiting examples of polyester depolymerization target products include polyester oligomers and monomers such as BHET, dimethyl terephthalate (“DMT”), ethylene glycol (“EG”), 1 ,4-cyclohexanedimethanol (“CHDM”) and diethylene glycol.

[0087] In embodiments that include polyester solids fed to or formed in the target polyester modifying zone, the modifying step may include in some embodiments a step of washing polyester solids with a wash solution (depicted as wash solution stream 104 in the Figures) to form a product stream 105 that includes as target product washed polyester solids. Exemplary suitable wash solvents include without limitation C3 to C7 ketones such as acetone, MIBK, MPK, or MAK, MIAK; C3-C6, preferably C3-C5 secondary and tertiary amides, for example Dimethylacetamide (DMAC) and dimethylpropionamide; C5-C8, preferably C5-C7 secondary and tertiary lactams and similar cyclic amides, C1 to C6, preferably C1 to C4 alkanols and glycols, such as methanol, ethanol, propanol isomers, butanol isomers, and ethylene glycol ; C4 to C10, preferably C4 to C6 Glycol ether / esters; C4 to C8 alkyl esters, preferably C5 to C6 esters; C7 to C10, preferably, 07 to 09, aromatic alcohols. In some embodiments, the wash solvent for the washing step is the same as one solvent of the least one solvent of the treating step. Wash solvent may be employed advantageously in the washing step at 0.5 / 1 to 4 / 1 mass ratio of wash solvent to polyester and at temperatures less than 130°C and more than about 20°C.

[0088] In one or more exemplary embodiments and as depicted in Figures, the step of recovering the solubilized polyester may include depolymerizing polyester in polyester recovering zone 100 to form product stream 105 that includes as target product(s) one or more polyester depolymerization products. In one or more embodiments, the step of recovering the undissolved polyester may include melting polyester solids to form a polyester melt and nay furtherinclude depolymerizing the polyester melt. As one of ordinary skill will appreciate, the identity and amount of the polyester depolymerization products in product stream 105 will vary depending on for example the amount and identity of polyesters in the feedstock, the type of depolymerization reaction and depolymerization reaction conditions. In non-limiting examples wherein the target polyester modifying step includes depolymerizing polyester, target products may include polyester oligomers and monomers such as dimethyl terephthalate (“DMT”), dimethyl isophthalate (“DMI”), ethylene glycol (“EG”), 1 ,4-cyclohexanedimethanol (“CHDM”), 2,2,4,4-tetramethylcyclobutane-1 ,3- dimethanol (“TMCD”), bis(2-Hydroxyethyl) terephthalate (BHET), diethylene glycol, 1 ,4-phenylenedimethanol or similar 1 ,3- or 1 ,2- phenylenedimethanol isomers. In one non-limiting example, the target product may be a hydrophilic target product such as hydrophilic short chain esters, including for example predominately hydroxyl-end capped, glycol or glycol end-capped target products such as produced for example by glycolysis depolymerization and the like. Exemplary target products of this general class include bis(2-Hydroxyethyl) terephthalate (BHET) and BHEI (ethylene-glycol end-capped hydrophilic esters and oligomers of chain length less than about 4 repeat units of ethylene glycol and tere- and iso-phthalates). In non-limiting examples such as wherein polyesters such as polyethylene terephthalate (PET) may be depolymerized via glycolysis in the recovering step (c) to produce a hydrophilic target product such as BHET, optional treating step (d) may include treating the product of the recovering step with a solvent that is hydrophobic or that includes a hydrophobic solvent or that includes a hydrophobic solvent for a contaminant. In general, “hydrophobic” is intended to describe and include materials that are immiscible in the recovering zone product under a given set of treating step conditions. Non-limiting examples of a hydrophobic solvents include generally aromatics ketones, for example one or more of C5 to C14 ketones, including a mix of C11 ketones commercially available from Eastman Chemical; more preferably C7-C12 ketones such as methyl propyl ketone (MPK), methyl amyl ketone (MAK), methyl isoamyl ketone (MIAK), di-isobutyl ketone (DIBK), methyliso-butyl ketone (MIBK), di-isopropyl ketone (DIPK), methyl isopropyl ketone (MIPK) and combinations such as mixes of C7 or C9 ketones sold by Eastman Chemical; 06 to 013 aromatics such as naphthalenes, xylenes and mixed xylenes; aromatic fluids known in the art as Aromatic 150, Aromatic 200, Solvesso™ 150 and Solvesso™ 200 and sold commercially by Exxon Mobil™ and combinations; C6 to C14 alkanes, preferably 07 to C11 alkanes such as undecane; and isoparaffin fluids such as Isopar™ L. Mixtures of two or more hydrophobic solvents are also contemplated, including for example a mix of xylene and a 07 ketone; a mix of Aromatic 150 and a C7 to C9 ketone; and a mix of Aromatic 200 with a C9 ketone.

[0089] In embodiments that may include depolymerizing polyester as the target polyester modifying step or as part of the target polyester modifying step, the depolymerizing step may be performed in the presence of one or more depolymerization catalysts (added to polyester recovering zone 100 as catalyst feed stream 101 in the Figures) and one or more depolymerization agent (added to polyester recovering zone 100 as depolymerization agent stream 102 in the Figures). Depolymerization agents may include methanol, 2- ethylhexanol, polyol such as glycol, or a combination thereof. Depolymerization catalysts may include Mn, Zn salts, potassium and sodium carbonates, carboxylates (e.g., acetate), or aromatic carboxylates, e.g., sodium monomethylterephthalate, potassium and sodium alkoxides, e.g., sodum methoxide or potassium 2-ethylhexoxide and combinations thereof. In embodiments that include a depolymerization step or which otherwise relate to recovery of polyester monomers through depolymerization, the method of the present invention may be described or labeled as a method for method for decontaminating a contaminated polyester depolymerization feedstock; the contaminated polyester recovery feedstock may be described or labeled as a contaminated polyester depolymerization feedstock; the polyester recovering zone may be described or labeled as a polyester depolymerization zone; and the decontaminated polyester recovery feedstock may be described or labeled as a decontaminated polyester depolymerization feedstock.

[0090] In embodiments that include depolymerizing as the target polyester modifying step or as a part thereof, the depolymerizing step may include known polyester depolymerization methods, processes, mechanisms and systems such as methanolysis depolymerization; alcoholysis depolymerization, e.g., using 2-ethylhexanol as the depolymerizing agent; glycolysis depolymerization, for example to form or recover target product bis(2-Hydroxyethyl) terephthalate (BHET); pyrolysis depolymerization; hydrolysis depolymerization; and catalyzed reaction of hydrogen with polyester at its ester bonds to reduce them to alcohols (which may be referred to as hydrogenolysis depolymerization). Suitable glycolysis methods are described for example in U.S. Pat. Nos. 3,257,335; 3,907,868; 6,706,843; and 7,462,649, the contents and disclosure of which have been incorporated herein by reference. Suitable methanolysis methods are described for example in U.S. Pat. Nos. 3,037,050; 3,321 ,510; 3,776,945; 5,051 ,528; 5,298,530; 5,414,022; 5,432,203; 5,576,456 and 6,262,294, the contents and disclosure of which have been incorporated herein by reference. The step forms a depolymerization product stream that may include target product and residual contaminant(s). Target product generally includes any monomer or oligomer generated by depolymerization of polyester may be exemplified by one or more of polyester oligomers, dimethyl terephthalate (“DMT”), ethylene glycol (“EG”), 1 ,4-cyclohexanedimethanol (“CHDM”) and diethylene glycol. In brief, hydrogenolysis depolymerization includes reacting hydrogen with polyester, typically in the presence of a catalyst such as a transition metal catalyst, to form target products that may include 1 ,4- phenylenedimethanol or similar 1 ,3- or 1 ,2- phenylenedimethanol isomers. In general, the catalyzed reaction of hydrogen occurs at the ester bonds of the polyester to reduce them to alcohols.

[0091] While this aspect of the method of present invention has been described in a method step sequence of treating, separating and recovering steps, one of ordinary skill will appreciate that the method of the present is not necessarily limited to a specified method step sequence and that other sequences are contemplated and are within the spirit and scope of theinvention. In one non-limiting example, the method may include a polyester recovering step subsequent to the treating step but preceding the separating step. Accordingly, in one or exemplary embodiments, the method may include for example treating in a treating zone a contaminated polyester recovery feedstock with a liquid solvent in which said polyester is substantially insoluble to form at least one modified contaminant and undissolved polyester in a carrier liquid; recovering the undissolved polyester in a polyester recovering zone to form a product stream comprising (i) polyester target product and optionally (ii) residual contaminants; and optionally separating modified contaminant in a separating zone. In another non-limiting example, the method may include a polyester recovering step preceding optional treating and separating steps. Accordingly, in one or more exemplary embodiments, the method may include dissolving polyester from a contaminated polyester recovery feedstock in a recovering zone to form a recovery product comprising (i) dissolved polyester and contaminants; separating dissolved polyester product from the recovery product; optionally precipitating dissolved polyester to form polyester precipitate; and optionally depolymerizing the polyester precipitate.

[0092] In one or more exemplary embodiments, the polyester recovering step may include cooling the polyester to an end solidifying temperature. A cooling profile for direct or indirect heat removal may span a temperature range from the dissolution temperature used for dissolution of the polyester in the polyester solvent to an end solidifying temperature at which a precipitating polyester is not sticky and forms free particles. In one or more exemplary embodiments, the end solidifying temperature may be less than 130° or less than 100°C. One preferred polyester recovering step may include direct or indirect cooling to induce precipitation of the polyester. Another preferred polyester recovering step may include adding an alkanol or alkane as a polyester recovery enhancement agent. Yet another preferred polyester recovering step may include adding water as a polyester recovery enhancement agent, wherein the polyester may be quench cooled, to precipitate and sink into a lower water layer, with the polyester solvent forminga second lighter organic phase. Any residual solvent remaining after precipitating the solubilized polyester may be removed vis distillation, for example via azeotropic distillation with water.

[0093] In one or more exemplary embodiments, the polyester recovering step may include washing polyester solids such as precipitate or crystallized material with a polyester wash solution. The polyester wash solution may at least partially remove residual materials such as one or more of residual contaminant, recovery enhancement agent and solvent. Washing may be performed using the same solvent as the treating step or different solvent than the treating step or any added antisolvent. Typical weight ratios of wash solution to polyester precipitate may range from 0.25:1 to 6:1 , more typically 0.5 / 1 to 2 / 1 or 0.75 / 1 to 3 / 1. The wash solution may include one or more of solvent, polyester recovery enhancement agent, and other materials suitable for washing such as solvents in which the contaminant(s) or solvent, or polyester recovery enhancement agent are soluble, or a combination of these. The polyester wash solution typically is fed at a polyester precipitate / wash solution ratio of 0.25 / 1 to 6 / 1. The washing may include displacement washing wherein the wash solution displaces interstitial liquid in a plug flow manner or may involve dilution washing wherein the wash solution combines with the polyester solids to form a slurry or other flowable form which may be transferrable to another vessel for further processing.

[0094] In embodiments including a step or substep of solidifying or precipitating or crystalizing solubilized polyester, such step / substep may include lowering the temperature of or adding an anti-solvent to the intermediate or a combination thereof, optionally followed by washing the crystallized or precipitated polyester to remove contaminants with a wash solution. The polyester precipitation step may be accomplished in a temperature range of 10°C to 110°C. Exemplary wash solvents are C3 to C7 ketones such as acetone, MIBK, MPK, or MAK, MIAK; C3-C6, preferably C3- C5 secondary and tertiary amides, for example Dimethylacetamide (DMAC) and dimethylpropionamide ; C5-C8, preferably C5-C7 secondary and tertiarylactams and similar cyclic amides, C1 to C6, preferably C1 to C4 alkanols and glycols, such as methanol, ethanol, propanol isomers, butanol isomers, and ethylene glycol ; C4 to C10, preferably C4 to C6 Glycol ether / esters; 04 to C8 alkyl esters, preferably C5 to C6 esters; 07 to 010, preferably, 07 to 09, aromatic alcohols. In other embodiments the wash solvent is the same solvent S2 used to dissolve or solubilize the polyester. Wash solvent may be employed advantageously at 0.5 / 1 to 4 / 1 mass ratio of wash solvent to polyester at temperatures less than 130°C and more than about 20°C.

[0095] Selection of an appropriate polyester antisolvent is dependent in part on the identity of the solvent used for treating the polyester in the treating step to from solubilized polyester, but the anti-solvent must be fully miscible with the treating step dissolution solvent. In one or more embodiments wherein the dissolution solvent is a cyclic or aliphatic amine, an aromatic, or an aromatic ester exemplary antisolvents are C1 to C6 alkanols or glycols, C3 to C7 ketones, C4 to C6 aliphatic esters, 06 to C9 aromatics, and C4 to 06 glycol ethers or esters. A typical ratio of anti-solvent to dissolution solvent may be from 0.5 / 1 to 6 / 1.

[0096] The present invention is described herein with respect to various interrelated aspects and embodiments and one of ordinary skill will understand and appreciate that elements or features used to describe one aspect or embodiment may be applicable and useful in describing other embodiments. Accordingly, descriptions and disclosure relating to elements or features of an aspect or embodiment of the present invention are hereby expressly relied on to describe and support those elements or features in other aspects or embodiments. More particularly, descriptions and disclosure relating to elements or features of the method for decontaminating a polyester recovery feedstock as described herein are hereby expressly relied on to describe and support those elements or features in the method for recovering a polyester from a contaminated polyester recovery feedstock as described herein, and vice versa.

[0097] While zones described herein such as the treating zone, separating zone, insoluble contaminant recovery zone, solubilized contaminant recovery zone and target polyester modifying zone are depicted as spatially separate in the Figures for convenience, one of ordinary skill will appreciate that treating, separating, recovering and modifying functions with the methods and systems of the present invention may overlap. In one non-limiting example, a treating zone may include some amounts or all of a separating function. In another nonlimiting example, a recovering zone may include some amounts or all of a modifying or separating function. Similarly, some amount of a contaminant treating function to form modified contaminant may occur in separating zone. Indeed, in one or more embodiments, separating zone may, as a spatial arrangement matter, overlap with or be partially or wholly contained within a treating zone. In some embodiments, therefore, the method may be described as batch, insofar as treating and separating steps are performed sequentially in a singular zone or sequentially in a singular vessel. In some embodiments, the method may be described as semi-continuous or continuous insofar as treating and separating steps may be performed at least partially in separate zones or vessels.

[0098] The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

Claims

THAT WHICH IS CLAIMED IS:

1. A method for recovering polyester from a contaminated polyester recovery feedstock comprising polyester and one or more contaminants, said method comprising (a) treating the contaminated polyester recovery feedstock in a treating zone with at least one solvent under conditions in which the polyester and at least one of the one or more contaminants are substantially solubilized in the solvent, forming treating zone product comprising solubilized polyester and, optionally, solubilized contaminant and insoluble contaminant; optionally (b) separating said insoluble contaminant from the treating zone product to form a solubilized polyester recovery intermediate comprising solubilized polyester and, optionally, solubilized contaminant; and (c) recovering said solubilized polyester in a polyester recovering zone to form a recovery product comprising (i) target polyester and optionally (ii) residual contaminants.

2. The method of claim 1 wherein said one or more contaminants and said polyester are substantially solubilized concurrently in said treating step (a).

3. The method of claim 1 wherein said one or more contaminants and said polyester are substantially solubilized in sequential substeps of said treating step (a).

4. The method of claim 3 wherein said treating step (a) comprises substep (a1 ) treating said contaminated polyester recovery feedstock with a solvent under conditions in which at least one of said one or more contaminants is solubilized and said polyester is substantially insoluble, forming a treating zone product intermediate comprising said one or more solubilized contaminants and unsolubilized polyester; substep (a2) removing said one or more solubilized contaminants from said treating zone product intermediate; and substep (a3) treating said treating zone product intermediate with a solvent under conditionsin which said unsolubilized polyester is solubilized, forming treating zone product comprising solubilized polyester.

5. The method of claim 4 wherein said solvent of substep (a1 ) and said solvent of treating substep (a3) are the same solvent from the standpoint of molecular structure.

6. The method of claim 5 wherein treating substep (a3) is performed at a temperature higher than the temperature of treating substep (a1 ).

7. The method of claim 4 wherein said solvent of substep (a1 ) and said solvent of substep (a3) are different types of solvent.

8. The method of claim 6 wherein the temperature of treating substep (a1 ) is no more than 130°C and the temperature of treating substep (a3) is at least 160°C.

9. The method of claim 6 further including a step of adding an additional amount of said solvent after substep (a2) and prior to or concurrent with substep (a3).

10. The method of claim 7 further including a step of adding an additional amount of said solvent after substep (a2) and prior to or concurrent with substep (a3).

11. The method of claim 1 wherein said one or more contaminants comprises one or more of cotton, olefin, spandex, PVC and polyamide.

12. The method of claim 1 wherein said contaminated polyester recovery feedstock comprises a polyester blend textile product comprising polyester fibers and one or more of cotton, olefin, spandex, PVC and polyamide fibers.

13. The method of claim 12 wherein said one or more contaminants comprises PVC and wherein the treating step comprises decomposing PVC to form HCI and a decomposed polyunsaturated PVC backbone and neutralizing said HCI with a neutralizing species to form a neutralized chlorine salt in said treating zone product.

14. The method of claim 13 wherein said neutralizing species is selected from the group consisting of alkali and alkali earth salts of C1 -C8 carboxylic and dicarboxylic acids, exemplified by acetic, propionic, butyric acid sodium, potassium, lithium, calcium, magnesium salts; alkali and alkali earth carbonate and bicarbonate salts, exemplified by sodium, potassium, lithium, calcium, magnesium carbonates and bicarbonates.

15. The method of claim 13 wherein said neutralizing species is soluble in said solvent.

16. The method of claim 13 wherein said neutralizing species is insoluble in said solvent.

17. The method of claim 13 further comprising a step of separating the neutralized chlorine salt from said treating zone product.

18. The method of claim 12 wherein said one or more contaminants comprises polyolefin and wherein the treating step includes melting said polyolefin to form a polyolefin melt in said treating zone product.

19. The method of claim 1 wherein said recovering step (c) comprises solidifying solubilized polyester to form polyester solids and optionally washing said polyester solids with a wash solution.

20. The method of claim 1 further comprising a step (d) of modifying said target polyester to form a target product recovery stream that comprises target product.21 . The method of claim 1 wherein said target polyester comprises polyester solids.

22. The method of claim 20 wherein said target product comprises solubilized polyester.

23. The method of claim 20 wherein said target product comprises polyester solids.

24. The method of claim 23 further comprising washing said polyester solids with a wash solution to form target product comprising washed polyester solids.

25. The method of claim 24 wherein said wash solution comprises a solvent that is the same solvent type as at least one solvent of said treating step.

26. The method of claim 20 wherein said modifying step comprises depolymerizing said target polyester to form target product that comprises depolymerized polyester monomer or oligomer.

27. The method of claim 20 wherein said modifying step comprises transesterifying target polyester with a glycol or polyol to form target product that comprises modified polyester or copolyester.

28. The method of claim 20 wherein said modifying step comprises melting polyester solids to form a polyester melt.

29. The method of claim 1 wherein said treating zone product comprises solubilized polyester and solubilized contaminant.

30. The method of claim 1 wherein said treating zone product comprises solubilized polyester and insoluble contaminant; or wherein said treating zone product comprises solubilized polyester, solubilized contaminant and insoluble contaminant.

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