Methods for recovering resins from post-consumer recycled thermoplastics

Abstract

The present technology generally relates to methods for recycling post-consumer resins comprising a rubber phase (ex: ABS or HIPS). The methods take advantage of the chemical degradation that occurred overtime in the resins via radical reactions with or without oxygen. These reactions are known to shorten polymeric chains by scission and / or to create oxygenated chemical moieties. The present technology either uses the chemical moieties to extract or react with the rubber phase in which these degradations occurred the most.

Description

[0001] METHODS FOR RECOVERING RESINS FROM POST-CONSUMER RECYCLED THERMOPLASTICS FIELD OF TECHNOLOGY

[0001] The present technology generally relates to methods for recovering resins from post-consumer recycled thermoplastics containing carbon-carbon double bonds. BACKGROUND INFORMATION

[0002] Since the discovery of Ziegler and Natta who evidenced the polymerization of alkenes by titanium and zirconium metallocenes in 1955,[1,2]the production of polymers has exponentially increase from the 50’s until today. The discovery and understanding of ionic polymerization by Szwarc et al.[3]and free radical polymerization[4]in the 50’s had a major role in the plastic production as well. In 2022, the amount of produced plastic has reached 400 billion tons globally.[5]

[0003] While these numbers testify to a healthy economy, it is important to know that when it comes to environmental concern, the situation is not exactly brilliant. Indeed, polymers does contain carbon-carbon or carbon-hydrogen bonds that remains stable over thousands of years, leading to a low decomposability and accumulation of these materials. Accumulation of polymers in oceans, rivers, landfill and forests are alarming and causes environmental issues. Plus, it is estimated that 20-50 million tons of Waste of Electrical and Electronic Equipment (WEEE) are discarded each year.[6]

[0004] The slow degradation of plastics over the years has meant that a large proportion of post- consumer recycled resins (pcr-resins) are no longer viable due to the loss of their mechanical properties.[7–12]This loss is largely explained by radical formation on the polymeric chains over a long period of time.[13–16]These radicals are slowly obtained under light / UV irradiation and / or upon heating of the polymers. The presence of radicals can lead to many undesired reactions such as scission of the polymeric chains, cross linking leading to deterioration of physical / mechanical properties.[7,12,16,17]Interaction between radicals and oxygen contained in the atmosphere generates peroxide radicals that creates, through several cascade reactions, oxygenated chemical moieties such as alcohols, ketones, aldehydes, ester, perester, anhydrides, ether and carboxylic acids.[16–18]These degradation reactions occurred in all styrenic and polyolefin resins but occurs more importantly in butadiene-based rubbers due to the presence of less stable C(sp2)=C(sp2) double bonds in the final material. The presence of these oxygenated chemical moieties and radicals leads to a large panel of possibilities to extract of recombine degraded chains. ABS (Acrylonitrile Butadiene Styrene terpolymer) and HIPS (High Impact PolyStyrene) are two examples or polymeric resins that are affected by these degradations due to their styrenic and rubbers phases.

[0005] Current resin solubilisation processes are applied to virgin resin and degrade the mechanical properties of the initial resin. In addition, current processes involving the solubilisation of plastic resin led to the same initial resin after the process.

[0006] As such, there remains a need in the art for methods that alleviates at least some of these drawbacks. To overcome these challenges, the methods described herein focus on pcr-resins. The properties of these pcr-resins, compared with those of virgin materials, make it possible to improve mechanical properties and access several types of material depending on the techniques used after solubilisation. SUMMARY OF TECHNOLOGY

[0007] In some aspects, the technology described herein relate to a method for recovering resins from rubber-based post-consumer recycled resins, the method including one or more of: a) removing a rubber phase from the rubber-based post-consumer recycled resins by liquid-liquid extraction; b) solubilizing and precipitating the rubber-based post-consumer recycled resins using polyreactive chemicals; c) performing sequential precipitation of the rubber-based post-consumer recycled resins to obtain high rubber-content resin and rubber-free resin; and d) performing selective solubilization of the rubber-based post-consumer recycled resins to allow separation of resins from the rubber-based post-consumer recycled resins.

[0008] In some aspects, the technology described herein relate to a method for recovering resins from rubber-based post-consumer recycled resins, the method including: a) solubilizing the rubber-based post- consumer recycled resins in an organic solvent to obtain solubilized rubber-based post-consumer recycled resins; b) filtration of the solubilized rubber-based post-consumer recycled resins of step a) to remove insoluble impurities; and c) performing liquid-liquid extraction of rubber content resin from the solubilized rubber-based post-consumer recycled resins with a polar solvent such that low rubber content resins are found in an organic phase and high rubber content resins are found in a polar phase. In some aspects, the method further comprises performing precipitation to obtain low rubber-content resin from organic phase and high rubber-content from aqueous phase.

[0009] In some aspects, the technology described herein relate to a method for recovering resins from rubber-based post-consumer recycled resins, the method including: a) solubilizing the rubber-based post- consumer recycled resins in a solvent including a reactive chemical; b) filtering the solubilized rubber- based post-consumer recycled resins to remove insoluble impurities; and c) precipitating the filtered solubilized rubber-based post-consumer recycled resins to obtain a rubber-based resin with improved mechanical properties.

[0010] In some aspects, the technology described herein relate to a method for recovering resins from rubber-based post-consumer recycled resins, the method including: a) solubilizing the rubber-based post- consumer recycled resins in a solvent; b) filtering the solubilized rubber-based post-consumer recycled resins to remove insoluble impurities; c) performing partial precipitation of the solubilized rubber-based post-consumer recycled resins to extract high rubber-content resins; and d) separating the high rubber- content resins from the solvent. In some instances, the method further comprises recovering by precipitation the rubber free solvent from the solvent.

[0011] In some aspects, the technology described herein relate to a method for recovering resins from blends containing rubber-based post-consumer recycled resins, the method including: a) solubilizing the rubber-based post-consumer recycled resins contained in blends in a solvent that solubilizes only the rubber-based resin; b) filtering the solubilized rubber-based post-consumer recycled resins to remove insoluble material; and c) performing precipitation to recover the solubilized rubber-based post-consumer recycled resin alone.

[0012] In one embodiment, the present technology relates to a method for recycling Post Consumer Resins (PCR) thermoplastics containing carbon-carbon double bonds (e.g., Acrylonitrile Butadiene Styrene terpolymer (ABS) and High Impact PolyStyrene (HIPS)). The method provides different grades of final recycled resins: high impact ABS, low and high rubber content ABS and SAN (Styrene AcryloNitrile) resins. In some instances, the method comprises a solubilization step, followed by a filtration step followed by a precipitation step followed by drying and extrusion of recycled resins. In some instances, the process comprises optional steps of liquid / liquid extraction and / or selective precipitation steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] All features of embodiments which are described in this disclosure are not mutually exclusive and can be combined with one another. For example, elements of one embodiment can be utilized in the other embodiments without further mention. A detailed description of specific embodiments is provided herein below with reference to the accompanying drawings in which:

[0014] Figure 1 is a schematic representation of a method for the treatment of rubber-based post- consumer recycled resins (pcr-resins) that uses a liquid-liquid extraction technique according to one embodiment of the present technology.

[0015] Figure 2 is a schematic representation of a method for the treatment of rubber-based post- consumer recycled resins (pcr-resins) that uses poly-reactive chemicals according to one embodiment of the present technology.

[0016] Figure 3 is a schematic representation of a method for the treatment of rubber-based post- consumer recycled resins (pcr-resins) that uses partial precipitation of solubilized pcr-resins according to one embodiment of the present technology.

[0017] Figure 4 is a schematic representation of all methods for the treatment of rubber-based post- consumer recycled resins (pcr-resins) that uses a dissolution process to separate two resins from one blend according to one embodiment of the present technology.

[0018] Figure 5 is a schematic representation of a method for the treatment of rubber-based post- consumer recycled resins (pcr-resins) according to one embodiment of the present technology.

[0019] Figure 6 is a graph showing concentration zone of pcr-ABS solution that allowed liquid-liquid extraction with distilled water.

[0020] Figure 7 are graphs showing FTIR spectra of recovered ABS from organic and aqueous phase after liquid / liquid extraction of pcr-ABS solutions at different concentrations. Zoom on the [880-1000] cm-1area. Spectra are calibrated on the CN stretch at 2237 cm-1. Left: ABS recovered from organic phase. Right: ABS recovered from aqueous phase.

[0021] Figure 8 is a graph showing qualitative phase content determination of ABS samples recovered from liquid / liquid extraction by TGA analyses.

[0022] Figure 9 are graphs showing qualitative phase content analysis by TGA of recovered ABS after liquid / liquid extraction of pcr-ABS solutions in different acetate solvent and extracted with different antisolvent.

[0023] Figure 10 is a graph showing FTIR spectra in the [1100-780]cm-1area of the different pcr-ABS material recovered from the organic phase after liquid / liquid extraction with distilled water. Spectra normalized on the CN stretch at 2237cm-1.

[0024] Figure 11 is a graph showing FTIR of HIPS materials recovered from aqueous and organic phase after liquid / liquid extraction process. Comparison is done with initial pcr-HIPS before processing. Spectra normalized on 1452 and 1493 cm-1stretches.

[0025] Figure 12 is a graph showing qualitative phase content determination of the different recovered ABS and SAN samples by TGA controlled degradation analyses.

[0026] Figure 13 is a graph showing FTIR of material recovered after the 2ndprecipitation step. Zoom on the [1800-800] cm-1area.

[0027] Figure 14 is a graph showing molecular weight of recovered SAN as a function of added methanolon ABS solution at 1stprecipitation step.

[0028] Figure 15 is a graph showing FTIR of extracted material from Magnum virgin ABS material. Poor signal at 966 cm-1.

[0029] Figure 16 is a graph showing FTIR analyses of soluble and insoluble materials recovered from pcr-PC / ABS blend solubilization in butyl acetate. No extra filtration of the liquid mixture was attempted.

[0030] Figure 17 is a graph showing DSC of different ABS material recovered after pcr-PC / ABS blend selective solubilization with butyl acetate.

[0031] Figure 18 is a graph showing FTIR spectra of different ABS material after pcr-PC / ABS blend after selective solubilization with butyl acetate.

[0032] Figure 19 is a graph showing DSC of initial pcr-PC / ABS beside PC and ABS recovered after separation by selective solubilization of each material from the initial pcr-PC / ABS blend.

[0033] Figure 20 is showing FTIR spectra of soluble and insoluble materials recovered from pcr-PC / ABS blend solubilization in butyl acetate with extra purification steps for recovered ABS.

[0034] Figure 21 is a general scheme of the process according to one embodiment of the present technology that can access to four different grades of resins starting from one pcr-resin.

[0035] Figure 22 is a general scheme of the of the steps to access high impact soluble resin from pcr resins containing a rubber phase.

[0036] Figure 23 is a schematic representation of the internal mixers that can be used or the precipitation steps.

[0037] Figure 24 is a general scheme of the of the steps to access low and high rubber content resins from pcr resins containing a rubber phase.

[0038] Figure 25 is a general scheme of the of the steps to access high rubber content resins and rubber free resin from pcr resins containing a rubber phase. DETAILED DISCLOSURE OF EMBODIMENTS

[0039] The present technology is explained in greater detail below. This description is not intended to be a detailed catalog of all the different ways in which the technology may be implemented, or all the features that may be added to the instant technology. For example, features illustrated with respect to one embodiment may be incorporated into other embodiments, and features illustrated with respect to a particular embodiment may be deleted from that embodiment. In addition, numerous variations and additions to the various embodiments suggested herein will be apparent to those skilled in the art in light of the instant disclosure which variations and additions do not depart from the present technology. Hence, the following description is intended to illustrate some particular embodiments of the technology, and not to exhaustively specify all permutations, combinations and variations thereof.

[0040] As used herein, the singular form “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise.

[0041] The recitation herein of numerical ranges by endpoints is intended to include all numbers subsumed within that range (e.g., a recitation of 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 4.32, and 5).

[0042] The term “about” is used herein explicitly or not, every quantity given herein is meant to refer to the actual given value, and it is also meant to refer to the approximation to such given value that would reasonably be inferred based on the ordinary skill in the art, including equivalents and approximations due to the experimental and / or measurement conditions for such given value. For example, the term “about” in the context of a given value or range refers to a value or range that is within 20%, preferably within 15%, more preferably within 10%, more preferably within 9%, more preferably within 8%, more preferably within 7%, more preferably within 6%, and more preferably within 5% of the given value or range.

[0043] The expression “and / or” where used herein is to be taken as specific disclosure of each of the two specified features or components with or without the other. For example, “A and / or B” is to be taken as specific disclosure of each of (i) A, (ii) B and (iii) A and B, just as if each is set out individually herein.

[0044] As used herein, the term “comprise” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded.

[0045] In some embodiments, the present technology stems from the discoverers’ elucidation of methods to recycle thermoplastics including styrenic and polyolefin resins in order to diminish both production of virgin material and accumulation of plastics in nature.

[0046] As used herein the expression "rubber-based post-consumer recycled resins" or "pcr-resins" refers to thermoplastics that comprise at least one rubber phase. Rubber here is defined as a material with rubbery properties and comprising carbon-carbon double bonds in their polymeric structure (e.g., polybutadiene, styrene-butadiene-styrene, ethylene propylene diene monomer terpolymer). Examples of such "rubber-based post-consumer recycled resins" are listed hereafter: Acrylonitrile Butadiene Styrene terpolymer (ABS), High Impact PolyStyrene (HIPS), blends of PolyButadiene (PB) or Styrene Butadiene Styrene terpolymer (SBS) or Ethylene Propylene Diene Monomer terpolymer (EPDM) or Nitrile Butadiene Rubber (NBR) or other rubber with thermoplastics such as Polypropylene (PP), Polycarbonate (PC), Polystryrene (PS), Styrene Acrylonitrile (SAN), PolyMethylMethAcrylate (PMMA), PolyVynilChlorine (PVC) or other.

[0047] In some embodiments, the present technology relates to methods to recycle post-consumer resins (pcr) comprising a rubber phase (e.g., ABS and HIPS). The methods take advantage of the chemical degradation that occurred overtime in the resins via radical reactions with or without oxygen. These reactions are known to shorten polymeric chains by scission and / or to create oxygenated chemical moieties.

[0048] In some embodiments, the methods of the present technology allow to recover resins from post- consumer resins (pcr-resins). In some implementations, the resins recovered from these methods have desirable chemical and / or physical properties.

[0049] In some embodiments, the methods of the present technology use chemical moieties to extract or react with the rubber phase in which these degradations occurred the most.

[0050] In some embodiments, the methods of the present technology use one or more of a liquid / liquid extraction, selective precipitation, selective solubilisation, and polyreactive chemicals to obtain high- and low-rubber resins, rubber-free resin, two separate materials (from a single blend) and mechanically improved materials, respectively.

[0051] In some embodiments, the present technology relates to a method for recovering resins from rubber-based post-consumer recycled resins (pcr-resins) that uses a liquid-liquid extraction technique (Figure 1). The method relies on solubilization of the pcr-resin in an organic solvent followed by extraction with a non-miscible protic polar solvent that attracts polymeric chains containing polar oxygenated moieties. Low rubber content resins is found in the organic phase while high rubber content resins remain in the polar protic solvent. This method allows to remove several pigments from pcr-resins to reachnatural color. As used herein, the expression "low rubber content resins" refers to resins that compriseless rubber than the initial resins onto which the method is applied, whereas the expression "high rubber content resins" refers to resins that comprise more rubber than the initial resins onto which the method is applied.

[0052] In one embodiment, the present technology relates to a method for recovering resins from rubber- based post-consumer recycled resins (pcr-resins) that uses poly-reactive chemicals. Poly-reactive chemicals interfere with oxygenated moieties or radicals or both to recombine degraded chains. The uses of poly-ol, polyamines, poly-ene, poly-acids, polyaldehyde and polythiols are convenient chemicals due to their ability for esterification reaction to generate esters, amides and thio-esters respectively, thus recombining two or more polymeric chains. Formation of acetal, hemi-acetal, thio-acetal, thio-hemiacetal or imide are also a possible way to recombine chains after reactions with ketones or aldehydes with alcohol or amine. Thiols are also known to form stable radical (toward water and oxygen) that can recombine polymeric chains by radical cross-linking. These recombinations allowed a recovery of impact resistance on tested recovered pcr-resins.

[0053] In one embodiment, the present technology relates to a method for recovering resins from rubber- based post-consumer recycled resins (pcr-resins) that uses precipitation of solubilized pcr-resins in order to remove shorter polymeric chains that were degraded overtime (Figure 3). The sequential precipitation of rubber containing resins showed that the first material to precipitate was high rubber content resins while extra precipitation step did crash out low molecular weight polymeric chains. In the case of ABS, it is shown that all rubber phase precipitated first with a part of SAN (Styrene AcryloNitrile copolymer). The extra precipitation step showed the precipitation of the remaining SAN phase (close to natural color).

[0054] In one embodiment, the present technology relates to a method for recovering resins from blends containing rubber-based post-consumer recycled resins (pcr-resins) that uses a dissolution process to separate two resins from one blend (Figure 4). The degradation of polymeric chains creates smaller chains which increases the solubility properties of pcr-resins. For example, in the case of pcr-PC / ABS blend, the pcr-ABS can be removed by solubilization from the blend to obtain two separated pcr-resins: PC and ABS respectively.

[0055] The partial extraction of the rubber phase of different rubber containing pcr-resins is shown using a liquid / liquid extraction process, supported by FTIR and TGA analyses. Then, the recovery of mechanical properties by chemical cross-linking using oxygenated moieties or radicals from pcr-resins and poly- reactive chemicals (alcohols, carboxylic acids, amines, or the like) is presented and highlighted by IZOD analyses. Furthermore, the removal of degraded shortened SAN polymeric chains from non-rubber phase is achieved by sequential precipitation and evidenced by FTIR, TGA and GPC analyses. Finally, the separation of one resin from pcr blends is shown with FTIR and DSC analyses.

[0056] In one embodiment, the present technology relates to a method for recovering resins from rubber- based post-consumer recycled resins, the method comprising removing a rubber phase from rubber- based post-consumer recycled resins by liquid-liquid extraction (Figure 1). In some implementations, themethod comprises: (1) solubilization of a rubber-based post-consumer recycled resin in a solvent; (2)filtration of the rubber-based post-consumer resin solution to remove insoluble impurities; (3) addition of a non-miscible solvent to the rubber-based post-consumer resin solution; (4) removal of rubber from rubber-base post-consumer resin by liquid / liquid extraction; (5) precipitation of materials from each liquid phase to obtain low rubber-content resin (solvent) high rubber content (non-miscible solvent). Liquid / liquid extraction is a process where components are separated from a liquid mixture by transferring them into an immiscible solvent. The solute selectively dissolves into the solvent, forming two distinct phases: the extract and the raffinate. This technique is commonly used for purification or isolation of specific compounds. In one embodiment, the present technology is describing the use of organic solvent as the solute. Acetates, Methyl Ethyl Ketone (MEK), TetraHydroFuran (THF), Toluene or other solvent that can solubilize rubber-based post-consumer recycled resins are suitable for liquid / liquid extraction as long as they are not fully miscible with the non-miscible solvent. The non-miscible solvent used for extraction are water, distilled water and ethylene glycol or a mixture of them with salts, acids, bases or other component that could help extraction.

[0057] In one embodiment, the present technology relates to a method for the treatment of rubber-based post-consumer recycled resins, the method comprising solubilizing and precipitating rubber-based post- consumer recycled resins using polyreactive chemicals to obtain mechanically improved recycled rubber-based post-consumer recycled resin (Figure 2). In some implementations, the method comprises: (1)solubilization of reactive chemical in a solvent; (2) solubilization of a rubber-based post-consumer recycled resin in the solvent comprising the reactive chemical; (3) filtration of the rubber-based post- consumer resin solution to remove insoluble impurities; (4) precipitation of the solubilized material to obtain a rubber-based resin with improved mechanical properties. In some implementations, polyreactive chemicals are molecules that comprises at least one chemically active moiety. A chemically active moiety can be referred as, but not restricted to carboxylic acid, alkene, aldehyde, alcohol, amine, imine, and thiol. Examples of polyreactive chemicals are, but are not limited to, 1,6-hexanedithiol, pentaerythritol, terephtalaldehyde, terephtalic acid, 1,5-hexadiene, tris(hydroxymethyl)aminomethane (referred as tris), and 1,6-hexamethylenediamine.

[0058] In one embodiment, the present technology relates to a method for the treatment of rubber-based post-consumer recycled resins, the method comprising performing sequential precipitation of the rubber- based post-consumer recycled resins to obtain high rubber-content resin and rubber-free resin (Figure 3). In some implementations, the method comprises: (1) solubilization of a rubber-based post-consumer recycled resin in a solvent; (2) filtration of the rubber-based post-consumer resin solution to remove insoluble impurities; (3) partial precipitation of the solubilized material to extract a high rubber-content resin; (4) separation of the high rubber-content resin from the remaining solvents; (5) precipitation of material remaining in the solvent to obtain a rubber-free material.

[0059] In one embodiment, the present technology relates to a method for the treatment of rubber-based post-consumer recycled resins, the method comprising performing selective solubilization of one pcr- resins from a polymer blend to allow separation of the two pcr-resins from one blend (Figure 4). In some implementations, the method comprises: (1) solubilization of a rubber-based post-consumer recycled resin blended with another resin in a solvent that solubilizes only the rubber-based resin; (2) filtration of the rubber-based post-consumer resin solution to remove the insoluble resin; (3) partial precipitation of the solubilized material to crash out the rubber-based post-consumer resin. Examples of solvents that may be used in this method include, but are not limited to: ethyl acetate, butyl acetate, toluene, and methyl ethyl ketone.

[0060] In one embodiment, the present technology relates to a method for the treatment of rubber-based post-consumer recycled resins, the method comprising: a) removal of a rubber phase from rubber-based post-consumer recycled resins by liquid-liquid extraction; b) solubilizing and precipitating of rubber-based post-consumer recycled resins using polyreactive chemicals to obtain mechanically improved recycled rubber-based post-consumer recycled resin; c) performing sequential precipitation of the rubber-based post-consumer recycled resins to obtain high rubber-content resin and rubber-free resin; and d) performing selective solubilization of one pcr-resins from a polymer blend to allow separation of the two pcr-resins from one blend (Figure 5). EXAMPLES Material and equipment

[0061] Chemicals and pcr-resins: Post consumer resin ABS (pcr-ABS), HIPS (pcr-HIPS) or pcr-PC / ABS parts (e.g. from WEEE) were collected and sorted in a mechanical recycling process at Lavergne Groupe. After the mechanical recycling process, pcr-ABS, pcr-HIPS and pcr-PC / ABS are separated and each polymer type can be further separated to three color categories: black, white and mixed colors. Variations of properties from lot to lot can be observed for the same pcr-resin.

[0062] Ethyl acetate (99%), butyl acetate (98%), amyl acetate (mixture of isomers, 98%), toluene (97%), methyl ethyl ketone (98%), cyclopentane methyl ether (98%), isopropanol (97%), ethyl benzene (97%), THF (97%), distilled water and methanol (99%) were ordered at VWR-Avantor. Ethylene glycol (99.5%), 1,6-hexanedithiol (98+%), Tris (99%), pentaerythritol tetrakis(3-mercaptopropionate) (90%), sulfuric acid (98%), hydroquinone (99%), pentaerythritol (98%), 1,6-hexamethyene diamine (95%), trimethylolpropane tris(3-mercaptopropionate) (85%), 1,6-hexanediol (95%), glycerol (99.5%), Tris.HCl (99%), Dodecanthiol (98%), ethanol (98%), propyleneglycol (99.5%), butane-2,3-diol (98%), 2,2’- thiodiethanethiol (95%), N,N,N’,N’-tetrakis(2-hydroxypropyl)ethylenediamine (98%), 1-hexene (98%), 1,5-hexadiene (98%), adipic acid (97%), trimethylolethane (97%), triethanolamine (97%), diethylene glycolamine (98%) were all ordered at VWR.

[0063] Equipment – reaction: Magnetic stirring hotplates from IKA and beakers from VWR were used to conduct the solubilizations and precipitations steps. Filtration were conducted with a 60-mesh metallic filter. The stirring for solubilization was done with magnetic bars. The stirring in the precipitation step was conducted with a mechanical stirrer from IKA. Liquid-liquid extraction was done manually in a closed Mason jar.

[0064] Equipment for sampling and analyses: Preparation of bars for IZOD notched impact measurement was done with a compression hot press from Carver Inc. Mold / plaques for hot press with ASTM D256 dimensions (63.5 x 12.7 x 3.18 mm) were designed internally. PTFE sheets were used in the compression molding under and above the ASTM D256 plaque to mold ABS testing bars.

[0065] Notcher from CEAST was used to notched ABS molded bars. The notch had an angle of 45°C and a diameter of 0.25mm. IMPACT INSTRON CEAST 9050 machine was used for IZOD notched analyses. ASTM D256 method with a 1J hammer were used for IZOD analyses.

[0066] FTIR were conducted on an iS10 SPECTROMETER KBr TGS MID-IR. Analyses were done on molded recovered pcr-resins after the different processes.

[0067] GPC analyses were performed at LCPM (Montreal University) with a WAT044228 – Styragel HR 5E column, a refractive index as a detector and THF as a mobile phase. The experiments were done with a 1.0mL / min flow at 30°C.

[0068] The TGA550 model from TA instrumental was used to run TGA analyses of our samples.

[0069] DSC analyses were conducted on the DSC 25 model from TA instrumental.

[0002]

[0070] Hot-press method for testing specimens. Set the temperature at 425°F (218°C) - 1.5min at 1 bar; Increase the pressure gradually within 30s to 2.5 bar. Release the pressure gradually within 30s to 0 bar. Immediately increase the pressure to 5 bar within 30s. Maintain the pressure for 30s. Release pressure in 30s to 0 bar. Increase the pressure to 1 bar and maintain it for 4min.

[0071] TGA and DSC analyses method: TGA analyses were conducted to qualitatively estimate the ratios of SAN, PB-g-SAN and PB phases in pcr-ABS (SAN stands for Styrene AcryloNitrile; PB for PolyButadiene and PB-g-SAN stands for PB grafted on SAN chains). The followed temperature procedure was taken from a previous literature report.

[0022] DSC analyses for Tg determination followed the ASTM D3418 method. Example 1 - Removal of rubber phase from rubber-based post-consumer recycled resins by liquid-liquid extraction.

[0072] Place a magnetic bar in a 250mL beaker and add ethyl acetate (EA) and additives. The final volume should be 160mL. Start heating the solution with stirring (400rpm). Cover the beaker tightly. Meanwhile, weigh out 14,6g (±0.05g) of pcr-ABS flakes. Add the flakes when the EA solution has risen above 58°C. Increase agitation during ABS addition to 800rpm. Allow the mixture to stir at 60°C for 1h30. Then switch off the heater but continue stirring as the opaque mixture cools down for 1h. Then filter the mixture into a 0,5L Masson jar with a 60-mesh filter. Wash insoluble pieces of plastic with ethyl acetate (2 x 15ml + 1 x 10mL). The 40mL of EA are passed through the same filter into the Masson jar. A 200mL opaque ABS solution is thus obtained in the Masson pot (the color of the solution depends on the initial color of pcr-ABS). Next, prepare 200mL of distilled water and add to the Masson jar. Shake the closed Masson jar vigorously for 30s. An emulsion is obtained. Leave to stand overnight (approx. 20h). Two phases are obtained: an opaque solution on top for the organic phase and a coarse emulsion at the bottom for the aqueous phase. Separate the two phases. Insoluble resins are dried 3h at 90°C.

[0073] Organic phase: Precipitate the organic phase by adding 7 volume equivalents of methanol (MeOH). Filter through a 60-mesh filter. Then wash the solid ABS with 2 x 100mL of MeOH which you will pass through the filter again. After washing, allow to evaporate for 15 min at RT. Place in oven at 90°C for 3h. A mass of 9 to 10g is generally obtained (69-76% of solubilized pcr-ABS).

[0074] Aqueous phase: Add 1 volume equivalent of isopropanol (iPrOH) to precipitate the extracted ABS in the aqueous phase. Filter the mixture through a 60-mesh filter. Wash the precipitated ABS with 2 x 100mLiPrOH, which you pass through the filter again. Allow the ABS to evaporate for 15 minutes, then place in a 90°C oven for 3 hours. A mass of 3-4.5g is generally obtained (23-34% of solubilized pcr-ABS).

[0075] The ABS powder recovered from the methods described herein may be molded as follows. The recovered ABS powder is then melted during 5min at 425°F. The pre-melted ABS is then manually molded into a ball which is then pressed in a disk mold (3mm wide, 12.5cm diameter) following the hot-press method for sampling. The disk is then allowed to cool down to RT over 15-30 mins. The disk is then manually cut into pieces of about 3 x 3 x 3 mm.

[0076] Disk for color analysis. 2,2g of previously cut ABS pieces are placed in a disk mold (25mm diameter, 3mm wide). The ABS is pre-melted at 425°F during 5 mins and then manually molded, while melted, in the mold disks. If necessary, two more minutes of pre-melting at 425°F can be added to pre- mold ABS in the disks. When this is done, the hot-press method for testing specimen preparation is applied. When finished, the disks are allowed to cool down for 15 to 30 mins and are unmolded manually.

[0077] The molded disks are allowed to be conditioned at least 2h in controlled atmospheric conditions (23°C and 50% RH) before testing.

[0078] The results show that a liquid-liquid extraction process applied to a post-consumer recycled rubber-based resin allows the extraction of the rubber phase from the pcr-resin.

[0079] If the solution of pcr-ABS is too concentrated, the liquid / liquid extraction does not occur. All tested concentration above 71.5 g / L leaded to absence of extraction by distilled water. On the opposite, all pcr- ABS solution at a concentration lower than 67.4 g / L did allow liquid / liquid extraction (Figure 6). It is as well important to note that a ratio of 1:1 between distilled water and the pcr-ABS solution volume needed to be respected. Otherwise, no extraction occurred. Finally, distilled water allowed liquid / liquid extraction while tap water did not.

[0080] With all these information in hand, all experiments will be conducted with a concentration around 67 g / L of dissolved ABS. Distilled water will be the extracting solvent and used with a 1:1 ratio compared with pcr-ABS solution.

[0081] After solubilizing the pcr-ABS and adding distilled water, the two-phases mixture was vigorously shaken for 30 seconds. A homogeneous emulsion was initially obtained. It took at least 4 hours for the mixture to stabilize. An opaque solution was obtained in the organic phase. The color depended on the pcr-ABS initially introduced. The volume of the organic phase decreased during the process as part of it remained in the aqueous phase in the form of a coarse emulsion. Degraded ABS chains are thought to act as surfactants, thanks to their polar oxygenated groups (created during degradation) and non-polar polymeric chains.

[0082] Both phases are separated and the ABS contained in each of them is precipitated by adding alcohol as anti-solvent (as described in the procedure part). FTIR shows that the stretch at 966cm-1is very low in intensity for the ABS recovered in the organic phase (ABSorg) while high for the ABS recovered in aqueous phase. Plus, ABSaqhad a rubbery texture and needed higher temperature (475°F instead of 425°F) to be molded.

[0083] To see if the concentration of the pcr-ABS solution had an impact on the Polybutadiene (PB) extraction, a 0.5L solution of 68.2 g / L was prepared and divided into seven solutions which were further diluted with ethyl acetate to reach a 100mL solution. After the liquid-liquid extraction with 100mL of distilled water, the recovered ABS from both phases were analyzed by FTIR. A zoom on the [900-1000] cm-1area is presented on Figure 7. The stretch at 966cm-1for C(sp2)=C(sp2)-H bounds in recovered ABS from organic phases increases when the concentration of the initial pcr-ABS solution decrease. These results showed that, the more the pcr-ABS solution is concentrated, the more PB is extracted from the initial pcr-ABS resin. It is however more complicated to make the same conclusion regarding the FTIR of ABS recovered from aqueous phase. Indeed, signals at 966 cm-1are all similar to each other.

[0084] TGA analyses were then conducted to qualitatively determine the ratio of SAN in each sample. SAN is reported to decompose under nitrogen at 365°C while PB degrades at 460°C and PB-g-SAN between 300 and 365°C.

[0022] While this method was internally demonstrated to be inadequate for quantitative determination of SAN and PB ratio in pcr-ABS, it is a great analysis to evaluate trends. Indeed, when tested on pure virgin SAN, some decomposition (around 15%) occurred at 460°C.

[0085] TGA analyses (Figure 8) showed that the rubber content in ABS recovered from aqueous phase (ABSaq) was higher than in ABS recovered from organic phase (ABSorg) while the SAN phase was predominant in the ABSorgand lower for ABSaq. This qualitative analysis confirmed what was observed with FTIR and further showed that rubber has been removed from pcr-ABS thanks to liquid / liquid extraction.

[0086] XRF analyses of the recovered resins showed that the brominated additives contained in the initial pcr-ABS were mostly removed by the process. Indeed, while received pcr-ABS generally contained around 2000ppm of Br, the extraction process showed that we could reach less that 500ppm of bromine (Table 1). The titanium and calcium containing additives (pigments, fillers or other) are mainly found in the ABS recovered from the aqueous phase. Other atoms such as Cl, Sb or Zn are removed as well. It is important to note that the extraction of these element can be increased using more appropriate stirring equipment. Table 1: XRF analyses of initial pcr-ABS (ABSi) and ABS recovered from both organic (ABSorg) and aqueous (ABSaq) phases after liquid / liquid extraction.

[0087] Colour measurements were conducted as well and showed that pigments were partially removed by the liquid / liquid extraction process (Table 2). Indeed, The ABS recovered from the organic phase is whiter (higher L value) than the initial pcr-ABS, meaning that carbon black was removed from the material. It was confirmed by the L value of the ABS recovered from the aqueous solution which had a lower L value, even with its high Ti content (generally from the white pigment TiO2). The extraction of carbon black was lower than on virgin resins.[19,20]It is thought that carbon black molecules react with polymeric chains overtime, creating C-C bond by radical reaction, leading to difficulties in extracting it.

[0023] Table 2: Color measurement of initial pcr-ABS (ABSi) and ABS recovered from both organic (ABSorg) and aqueous (ABSaq) phases after liquid / liquid extraction.

[0088] It is important to note that the same process applied on virgin ABS resins (Terluran GP 22 and Magnum 3522 MT natural color) was not effective at any concentration of ABS solution. No rubber nor SAN was extracted from the virgin resins during liquid / liquid extraction.

[0089] Influence of water miscibility: After designing the best parameters for rubber extraction from ABS pcr-resins through liquid / liquid extraction, the influence of water solubility in organic solvent was studied. The hypothesis is: the less the water interacts with the organic solvent, the better the polar moieties are extracted and so the degraded rubber phase.

[0090] For this matter, four solvents were chosen: methyl ethyl ketone, ethyl acetate, butyl acetate and amyl acetate. Their solubility in water at 20°C are 292, 85.3, 4.3 and 0.9 g / L respectively (from GESTSIS substance database).14.6g of a new batch of pcr-ABS were dissolved in 160mL of each selected solvent at different temperatures. After solubilization, filtration and washings, a one-time liquid / liquid extraction with antisolvent at a 1 / 1 ratio is done followed by overnight settlement. Results are presented in Table 3. Table 3: Sum-up of liquid / liquid extraction results with different organic solvent at different solubilization temperatures.

[0091] First, while MEK is a very good solvent for ABS, its high solubility in water avoids any reliable extraction. The results presented in Table 3 confirm the hypothesis that the less the solvent is miscible with water, the more the polar function are extracted from the ABS solution. Indeed, more material is extracted from the pcr-ABS solution with the most hydrophobic solvent (amyl acetate – 60% vs 39% for ethyl acetate). Extracting ABS with ethylene glycol from its amyl acetate solution even went up to 67% extraction.

[0092] On top of material extraction, the L value of each material is increasing while water miscibility decreases, leading to a L value as high as 41,9 for amyl acetate. It is known that carbon black particles contain polar functions on their surface,

[0024] which can be attracted by a polar protonated solvent such as water. Decreasing the miscibility of water in the organic solvent used to solubilize ABS did increase, as well, carbon black extraction, according to the L value reported. However, as mentioned previously,carbon black is known to increasingly interact with polymeric chains over time in the material.

[0023] Ascarbon black remained for years in the pcr-ABS, the extraction rate of the pigment can not lead to higher L value. Surprisingly, ethylene glycol does not seem to efficiently extract carbon black (L value of only 31.0).

[0093] Phase content ratio of the different recovered material was qualitatively determined by TGA analysis (Figure 9). The ABS recovered from the organic phase contains around 50 to 60% SAN (qualitative), compared with about 40% for the initial material. It shows as well than less rubber is decomposed from ABS recovered from amyl acetate compared with butyl acetate (15 vs 20% respectively). Surprisingly, the rubber phase of the material recovered in water from the ABS solution in butyl acetate contain highly more rubber phase (55%) than the one recovered after extraction with amyl acetate (30%). When using ethylene glycol instead of distilled water, the extraction of rubber is well highlighted by a 55% rubber content in the recovered material from aqueous phase.

[0094] When looking at the FTIR spectra (Figure 10) of the different material recovered from the organic phases, it is clearly shown that vinylic stretch at 966 cm-1is almost not present anymore when butyl and amyl acetate are used as organic solvent. The rubber phase is reported as the most reactive phase in ABS, which induces the presence of more polar functions after degradation over time. These latest can then be easily extracted by water, thanks to hydrogen bonding, especially when the solubility of water in the organic solvent is low. These FTIR analyses confirm TGA results presented previously: the less the acetate solvent is miscible with water, the more the rubber phase is extracted from the ABS.

[0095] Liquid / liquid extraction of HIPS material: High Impact PolyStyrene (HIPS) is a similar material in terms of phases compared to ABS. HIPS is composed of rubber particles surrounded by a polystyrene phase. pcr-HIPS being produced at Lavergne as well as pcr-ABS, the material was tested on the same process developed for pcr-ABS.

[0096] The same liquid / liquid extraction procedure (from the procedure section) was followed but pcr- HIPS was dissolved in ethyl acetate instead of pcr-ABS. After liquid / liquid extraction with distilled water, the aqueous phase, being a coarse emulsion, represented 75% of the overall volume. After precipitating both materials from organic and aqueous phase, it is shown that only 15% of solubilized HIPS remained in the organic phase (HIPSorg) and 85% were extracted by the aqueous phase (HIPSaq). Plus, when looking at the FTIR spectrum of all HIPS materials (Figure 11), these latter are all very similar. Rubber phase is not extracted prior to other phases. The hypothetic higher solubility and hydrophobicity of SAN phase, compared with PS phase may explain these results. Example 2 - Mechanical properties recovery of rubber-based post-consumer recycled resins by adding polyreactive chemicals during a solubilization / precipitation process.

[0097] In a 250mL beaker, 160mL of ethyl acetate were added with chemical additives (1.97.10-3mol). The mixture is heated to 60°C.22(±0.05)g of pcr-ABS flakes are then added to the solution. The mixture is allowed to stir for 1.5h at 60°C. The mixture is then allowed to cool down to room temperature (RT) within 1h. It is then filtered with a 60-mesh metal filter to give a 160mL opaque “solution” (the color will depend on the color of the pcr-ABS regrinds used). The insoluble impurities captured on the filter or left in the beaker are washed with ethyl acetate (2 x 15mL and 1 x 10mL) to collect as much of dissolved ABS as possible. All washing solutions are filtered through the same 60-mesh filter and added to the initial 160mL “solution”, leading to a 200mL opaque “solution”. This solution is added in a 2L beaker with an overhead mechanical stirrer. Under high stirring speed (>1000rpm), 1,4L of methanol are added in 5- 10s and the stirring was maintained for 5min after the methanol is added. The ABS precipitates and a blurry mixture of different colors (depends on initial pcr-ABS) is obtained. The mixture (precipitated ABS particles suspending in the solvents) is then filtered through a 60-mesh filter. The obtained ABS powder is washed two times with methanol (2 x 200mL). Methanol was removed by filtration through the same filter. The final grey powder is then allowed to evaporate at RT for 15min. The powder is then put in a 90°C oven for 3h. The final recovered ABS is a dry grey powder. Yields are always located between 78 and 85% representing 17.2 to 18.7g. Yields calculated after removing the mass of insoluble impurities are located between 90 and 95%.

[0098] The ABS powder recovered from the methods described herein may be molded as follows. The recovered ABS powder is then melted during 5min at 425°F. The pre-melted ABS is then manually molded into a ball which is then pressed in a disk mold (3mm wide, 12.5cm diameter) following the hot-press method for sampling. The disk is then allowed to cool down to RT over 15-30 mins. The disk is then manually cut into pieces of about 3 x 3 x 3 mm.

[0099] Bars for impact resistance tests. The previously cut ABS pieces are placed in the mold for ASTM D256 bars.2,50-2,53g are added in each mold cavity. The ABS is pre-melted at 425°F during 5min and then manually molded, while melted, in the mold bars. If necessary, two more minutes of pre-melting at 425°F can be added to pre-mold ABS in the ASTM bars. When this is done, the hot-press method for testing specimen preparation is applied. When finished, the bars are allowed to cool down for 15 to 30 mins and are unmolded manually.

[0100] The molded bars are allowed to be conditioned at least 2h in controlled atmospheric conditions (23°C and 50% RH) before testing.

[0101] In this context, several chemicals are tested with the same concentration (1.97x10-3mol). Beside few exceptions, chemicals with low or no toxicity were chosen. Without any added chemical, the obtained IZOD notched impact value is only of 48.3 J / m (Table 4, entry 1). The presence of radicals in the solid state creates slow degradation due to low Brownian motion. However, in liquid phase, Brownian motion is greatly increased, leading to fast radical degradation as described in introduction (chain scission, reaction with oxygen). This fast degradation leads to low impact resistance of material after solubilization, which is not the case for post-industrial or virgin resins.

[0102] As soon as a protonated chemical is part of the process, the impact resistance is getting higher. It is thought that the protons from alcohol, thiol or amine stopped undesired radical reaction. For example, when adding ethanol or dodecanethiol (Table 4, entry 2 and 14, respectively) in the mixture, the impact strength is increased by almost 20% compared with the reference material (entry 1).

[0103] Going from mono-reactive chemicals to polyreactive chemicals (ex: from ethanol to ethylene glycol or pentaerythritol) did increase even more the impact resistance of our ABS samples. The minimum increase was obtained for diethylene glycolamine and was of 18.6% (Table 4, entry 29) while the best results was obtained with 1,6-hexanedithiol (1,6-HDT) with a 80.3% increase compared with reference material (Table 4, entry 15). It shows the benefit of using poly-(ol / thiol / amine / ene / acid / aldehyde) instead of mono-(ol / thiol / amine / ene / acid / aldehyde). It is thought that these polyfunctional agents act as cross- linker between degraded polymer chains by reaction with end chain aldehyde, ketones, carboxylic acids or other oxygenated moieties. However, there is no trend regarding the number of chemically active functions on the impact resistance. A diol can give better results than a tetra-ol (Table 4, entry 3 vs 11). The opposite is also true (Table 4, entry 4 vs 13).

[0104] In order to improve the efficiency of the reactivity of our polyreactive chemical, the same reaction was conducted with dried pcr-ABS and dried ethyl acetate. It was thought that removing water would displace the reaction on the right as it works for classic esterification reactions. Using pentaerythritol as an example (Table 4, entries 11 & 12), an increase of 20.1% in impact resistance is observed in these conditions, showing the advantage of working in dry conditions. Table 4: IZOD values of recovered ABS after reaction in ethyl acetate with different alcohol, thiol, amine, carboxylic acids, aldehydes, alkene or mixed chemicals / binder. Each time, three samples were tested. Quadrol: N,N,N′,N′-Tetrakis(2-Hydroxypropyl)ethylenediamine ; THEED : 2,2′,2″,2″′- (Ethylenedinitrilo)tetraethanol ; TP3MP : Trimethylolpropane tris(3-mercaptopropionate) ; PT4MP : Pentaerythritol tetrakis(3-mercaptopropionate). Tris: tris(hydroxymethyl)aminomethane.aChemicals were only partially soluble in ethyl acetate.bEthyl acetate was previously dried over molecular sieve (4A) and ABS was dried 6h at 90°C.

[0003]

[0105] When looking at thiols, their reactivity looks enhanced compared with amines, carboxylic acids, and alcohols. It is thought that thiols can proceed to both thio-esterification and radical reaction. Indeed, thio radicals are very stable towards water and oxygen and can react with carbon-carbon double bonds,

[0025] leading to a better linking between degraded polymeric chains and a better impact resistance.

[0106] A different trend is observed for alkenes. Indeed, 1-hexene is found to be an ideal additive for impact strength recovery of pcr-resins while being a mono-reactive group (Table 4, entry 25). It is thought that radicals from pcr-resins does react with 1-hexene which added flexibility to the structure by adding flexible alkane branch. The same trend is observed when adding 1-hexene during ethylene polymerization.

[0026] However, 1-octene being less reactive towards radical,

[0027] the impact increase is less significant (Table 4, entry 26). For comparison, 1,5-hexadiene and 1,7-octadiene (Table 4, entry 27 & 28) seemed ineffective for impact strength improvement of pcr-ABS. In that particular case, adding more reactive groups (alkene) does not induce a higher increase of IZOD value.

[0107] It is important to note that this process did remove additives. XRF analyses did show decrease of bromine content from 2000ppm to 200ppm in average. Values of less than 50ppm of bromine were obtained as well. Sb and Cl content were greatly decreased as well from 93 and 157 ppm to 32 and 68 respectively in average.

[0108] Comparison between pcr-ABS with virgin ABS: To show that the method can be applicable only to pcr-ABS and not post-industrial or virgin ABS, the same tests carried out with two commercial ABS grades: Terluran GP22 from Ineos and Magnum 3522 MT natural from Trinseo. They are emulsion and bulk polymerized ABS, respectively. It is expected that degradation of the polymer matrix has not yet occurred, meaning that the presence of oxygenated groups and radicals is scarce. Impact resistance of recovered ABS material after solubilization process is presented in Table 5.

[0109] For the Terluran case, the addition of 1,6-hexanedithiol did not have an influence on the impact strength of the virgin material while the addition of Tris did cause a 11.5% decrease of impact strength. Similarly, Magnum ABS was tested as well. As for Terluran, the addition of Tris and 1,6-hexanedithiol did not bring any significant improvement of impact resistance compared to what it brings to pcr-ABS. The impact of added polyreactive chemicals is limited on this virgin ABS compared with pcr-ABS. Indeed, the absence of radical or oxygenated groups avoid polyreactive chemicals to crosslink polymeric chains. These results also highlight that the way of ABS had been synthesized (bulk vs emulsion polymerization) had no influence on the final trend. Table 5: Impact of poly-reactive chemicals on two virgin ABS resins: Terluran GP 22 and Magnum 3522MT (emulsion and bulk polymerized ABS respectively).

[0110] To further confirm the theory that poly functional chemicals react with degraded moieties or radicals that formed over time in ABS resins, the Terluran material was aged during 4872h (203 days) at 80°C. Following the aging, the ABS is processed by dilution the same way as previous experiments. Results are summed up in Table 6. First, compared with non-aged ABS, there is a drop of 30 J / m for impact strength of the material after solubilization / precipitation (122.5 to 93.0 J / m), showing the material was strongly degraded. When 1,6-HDT is added in the mixture during solubilization of aged ABS, it allows to recover initial impact resistance of Terluran ABS, proving one more time that the added polyfunctional chemical is reacting with either degraded moieties or radicals formed during aging. Table 6: Impact strength of aged Terluran ABS (4872h - 80°C) after dissolution / precipitation process in ethyl acetate.

[0111] Concentration of poly-functional additives: The influence of poly functional chemicals concentration on solubilized pcr-ABS was then investigated. For this study, of the two best candidates were chosen: 1,6-HDT and Tris. Results are presented on Table 7. Decreasing the amount of 1,6-HDT did decrease the impact resistance of recovered ABS while increasing the quantity of 1,6-HDT did not significantly increase the impact resistance of ABS. A plateau has been reached between 12 and 16 mmol / L. After the plateau, the impact decreases again, surely due to higher crosslinking reactions that rigidify the rubber phase. A similar trend is observed with Tris. Higher concentrations were not accessible due to low solubility of Tris in ethyl acetate. Table 7: Influence of polyreactive chemical concentration on IZOD values of recovered ABS resins.

[0004]

[0112] Influence of solvent on impact strength recovery: In this section was studied the influence of solvent on impact recovery of pcr-ABS. First solubilization attempts with Cyclopentyl Methyl Ether (CPME) and ethyl benzene were not conclusive due to low solubility of pcr-ABS at 60°C (23 and 44% respectively). Results with other tested solvent are reported in Table 8.1,6-HDT and terephtalaldehyde were used as reference polyreactive chemicals for this study. From all solvent tested, ethyl acetate performs the best (up to 80% impact resistance recovery). Butyl acetate, which is similar to ethyl acetate, performs correctly as well (up to 71,3 J / m). However, toluene and THF avoid significant impact resistance improvement for pcr-ABS, even in the presence of polyreactive chemicals.90°C were needed for toluene to correctly solubilize ABS which can explain the low impact resistance values. THF solubilizes both pcr- ABS and other unwanted impurities that may avoid impact resistance rise.

[0113] Interestingly, for toluene, THF and acetates without added chemicals, the IZOD value of final recovered ABS is located around 50 J / m. On the opposite, the impact resistance obtained for recovered ABS from Methyl Ethyl Ketone (MEK) is 72 J / m, without added chemicals. MEK being able to react with radicals and oxygen to form new reactive sites,

[0028] it can explain the high impact resistance of recovered ABS. Added polyreactive chemicals did improve slightly more the impact resistance up to 80 J / m.

[0114] In conclusion of this study, the best solvent for impact resistance recovery of pcr-ABS are acetates for their ability to dissolve only ABS and being inert. MEK is a very interesting candidate for its reactivity that is able to improve pcr-ABS properties. Table 8: Influence of solvent on mechanical properties recovery. MEK: Methyl Ethyl Ketone. THF: TetraHydroFuran. * Solubilization done at 90°C instead of 60°C.

[0005]

[0006]

[0115] Polyreactive chemicals influence on high impact polystyrene (HIPS) during solubilization / precipitation process: The same experiments were conducted with pcr-HIPS in ethyl acetate (60°C). Results are reported in Table 9. The impact resistance of pcr-HIPS was very low (26.5 J / m) after the solubilization / precipitation process. Polyreactive chemicals (12.3 mmol / L) added during solubilization were not able to allow the recovery of a decent impact resistance for pcr-HIPS material.Similarly, MEK is reported to be the best solvent for impact recovery of pcr-ABS. It has the opposite effectwhen applied with pcr-HIPS. Table 9: Impact resistance of recovered pcr-HIPS after solubilization / precipitation process with or without polyreactive chemicals. Example 3 - Sequentia (1.97.10-3mol). The mixture is heated to 60°C. 22(±0.05) g of mechanical recycling treated pcr-ABS regrinds are then added to the solution. The mixture is allowed to stir for 1.5h at 60°C. The mixture is then allowed to cool down to room temperature (RT) within 1h. It is then filtered with a 60-mesh metal filter to give a 160mL opaque “solution” (the color of the solution will depend on the color of the pcr-ABS regrinds used). The insoluble impurities captured on the filter or left on the beaker are washed with ethyl acetate (2 x 15mL and 1 x 10mL) to collect as much dissolved ABS as possible. All washing solutions are filtered through the same 60-mesh filter and added to the initial 160mL “solution”, leading to a 200mL opaque “solution”. The mixture is then added to a 500mL beaker. 100 to 120 mL of methanol is then added to the mixture under strong mechanical stirring, leading to the precipitation of a wax and a translucid solution. The liquid phase is then separated from the wax.

[0117] Wax phase. While wet, the wax is immediately solubilized again in 50mL of ethyl acetate. 350 mL of methanol is then added to the mixture under strong mechanical stirring. An ABS powder crashed out from the mixture which was stirred over 5min. The ABS was recovered thanks to filtration with a 60- mesh metallic filter. The ABS is washed two times with methanol (100mL). The ABS is allowed to evaporate over 15min at RT and is then dried over 3h at 90°C.11 to 15g of ABS are obtained (50 – 68%).

[0118] Liquid phase. One volume equivalent of MeOH is added to the previously recovered liquid phase under strong mechanical stirring. A white solid crashed out from the solution. The mixture was stirred during 5min. The solid was recovered thanks to filtration with a 60-mesh metallic filter. The solid is washed two times with methanol (50mL). The ABS is allowed to evaporate over 15min at RT and is then dried over 3h at 90°C.4 to 7g of white solid are obtained (18 – 32%).

[0119] The ABS powder recovered from the methods described herein may be molded as follows. The recovered ABS powder is then melted during 5min at 425°F. The pre-melted ABS is then manually molded into a ball which is then pressed in a disk mold (3mm wide, 12.5cm diameter) following the hot-press method for sampling. The disk is then allowed to cool down to RT over 15-30 mins. The disk is then manually cut into pieces of about 3 x 3 x 3 mm.

[0120] Bars for impact resistance tests. The previously cut ABS pieces are placed in the mold for ASTM D256 bars.2,50-2,53g are added in each mold cavity. The ABS is pre-melted at 425°F during 5min and then manually molded, while melted, in the mold bars. If necessary, two more minutes of pre-melting at 425°F can be added to pre-mold ABS in the ASTM bars. When this is done, the hot-press method for testing specimen preparation is applied. When finished, the bars are allowed to cool down for 15 to 30 mins and are unmolded manually.

[0121] The molded bars are allowed to be conditioned at least 2h in controlled atmospheric conditions (23°C and 50% RH) before testing.

[0122] In this part, we report that partial precipitation of rubber-based pcr-resins allows to obtain high rubber content material and material free of rubber. This third claim does use the same experimental process than described in claim 2 until precipitation.

[0123] Effect of partial precipitation of pcr-ABS solutions: At this point, the ratio of anti-solvent / solvent in volume was large (7 eq.). A ratio equal to 0.7 or more did crash out the entire pcr-resin as a wax or a solid powder. On the contrary, ratios under 0.7 and above 0.5 implied the formation of a slime at the bottom of the beaker which can easily be separated from the supernatant. After quick solubilization of this wax with the solvent (50mL in the case of ethyl acetate) and precipitation with 7 equivalents in volume of methanol, different grades of high rubber content resins are obtained. It is to be noted that the less anti-solvent is added, the more material was recovered in the supernatant (Table 10). Table 10: Influence of the precipitation ratio. For this example: pcr-ABS is used as the rubber-based pcr- resins. Ethyl acetate is the solvent. 1.97 mmol of ethylene glycol is added in the process before solubilization of pcr-ABS. Precipitations are done with methanol. ABSPB: high rubber content ABS.

[0124] TGA analyses were then conducted to qualitatively determine the ratio of SAN (Styrene AcryloNitrile) in each sample (Figure 12). SAN is reported to decompose under nitrogen at 365°C while PB degrades at 460°C and PB-g-SAN (PB chains grafted on SAN) between 300 and 365°C.

[0022] While this method was internally demonstrated to be inadequate for quantitative determination of SAN and PB ratio in ABS, it is a great analysis to see trends. Indeed, when tested on pure virgin SAN, some decomposition (around 15%) was observed at 460°C. Nevertheless, trends were observed on the samples obtained after the partial precipitation tests (Figure 12). It was highlighted that the more methanol is added to the pcr-ABS solution, the higher SAN content was observed in the first precipitated resin. Indeed, when 7 equivalents of MeOH are added to the ABS solution (102 g.L-1), a large SAN content is observed in the recovered ABS. On the opposite, a lower amount of SAN is detected by TGA when 0.5eq of MeOH are added to precipitate ABS. More importantly, the recovered material from the supernatant obtained after first precipitation did show a large majority of SAN content showing that SAN was extracted from pcr- ABS.

[0125] It is as well important to note that all sample recovered at the second precipitation did exhibit a negligeable polybutadiene stretch at 966 cm-1in FTIR analyses (Figure 13). It confirmed that mostly SAN material is extracted from initial pcr-ABS. FTIR of material recovered at both 1stand 2ndprecipitation.

[0126] It is as well shown that removing a part of SAN from pcr-ABS did increase the impact resistance of the material. Indeed, from 76.3 J / m for 7eq methanol, values of 82 to 86 J / m were obtained thanks to partial precipitation (Table 10). However, our sampling method was not adapted to the material precipitated with 0.5 eq of MeOH. Indeed, the high rubber content did not allow a proper molding of the IZOD bars which explain that the impact resistance was not further improved.

[0127] When adding less methanol on the ABS solution, the final quantity of recovered SAN was increased, meaning that more SAN was soluble in the ethyl acetate / methanol mixture. When speaking about polymer, solubility can be linked with molecular weight of the polymer. GPC analyses in THF of the recovered SAN after extraction did indeed show that, the less methanol is added at 1stprecipitation, the higher the molecular weight is (Figure 14).

[0128] The variation of molecular weight in the SAN phase of pcr-ABS allows selective precipitation. This variation can be explained by (1) degradation of the polymeric chains by scission reactions or (2) by the pcr-ABS blend we use that come from different sources.

[0129] For comparison, the same experiment was performed with both Magnum and Terluran ABS virgin material. After their solubilization in ethyl acetate at 60°C, 0.5 volume equivalent of methanol were added on the mixture. Most of ABS crashed out. The supernatant was then separated from the ABS wax and extra methanol was added to precipitate the remaining soluble material in the ethyl acetate / methanol mixture. Compared with pcr-ABS, the amount of material that can be extracted from virgin ABS is way lower; 9,1% for Magnum and only 1,8% for Terluran. The FTIR of extracted material from Magnum does show a very poor signal at 966 cm-1, showing that, as for pcr-ABS, mostly SAN is extracted (Figure 15). While in pcr-ABS, scissions reactions occurred over the years, leading to shorter SAN polymeric chains, it is not the case for virgin ABS. The expected low variation of molecular weight in these latter avoid a proper extraction of SAN from the initial resin. Example 4 - Selective solubilization of one pcr-resins from a polymer blend to allow separation of the two pcr-resins from the blend.

[0130] In a 250mL beaker, 160mL of ethyl acetate were added. The mixture is heated to 60°C.20(±0.05)g of mechanical recycling treated pcr-PC / ABS regrinds are then added to the solution. The mixture is allowed to stir for 2h at 60°C. The mixture is then allowed to cool down to room temperature (RT) within 1.5h. It is then filtered with a 60-mesh metal filter to give a 160mL opaque “solution” (the color will depend on the color of the pcr-PC / ABS regrinds used). The insoluble impurities captured on the filter or left on the beaker are washed with ethyl acetate (2 x 15mL and 1 x 10mL) to collect as much dissolved ABS as possible. All wash solutions are filtered through the same 60-mesh filter and added to the initial 160mL “solution”, leading to a 200mL opaque “solution”. This solution is added in a 2L beaker with the overhead mechanical stirrer. Under high stirring speed (>1000rpm), 1,4L of methanol are added in 20-40s and the stirring was maintained for 5min after the methanol is added. The ABS precipitates and a blurry mixture of different colors (depends on initial pc-PC / ABS) is obtained. The mixture is then filtered through a 60- mesh filter. The obtained powder is washed two times with methanol (2 x 100mL). Methanol was removed by filtration through the same filter. The final powder is then allowed to evaporate at RT for 15min. Both the powder and insoluble material are put in a 90°C oven for 3h. The yields depended on the initial pcr- PC / ABS used. The addition of two yields usually gave 98% of material recovery.

[0131] The ABS powder recovered from the methods described herein may be molded as follows. The recovered ABS powder is then melted during 5min at 425°F. The pre-melted ABS is then manually molded into a ball which is then pressed in a disk mold (3mm wide, 12.5cm diameter) following the hot-press method for sampling. The disk is then allowed to cool down to RT over 15-30 mins. The disk is then manually cut into pieces of about 3 x 3 x 3 mm.

[0132] The molded material are allowed to be conditioned at least 2h in controlled atmospheric conditions (23°C and 50% RH) before testing.

[0133] In this part, the separation of two pcr-resins from one pcr-blend by solubilization / filtration technique is discussed. One example is reported with pcr-PC / ABS blends (PC stands for PolyCarbonate). 20g of pcr-PC / ABS resins are solubilized in solvents during 2h (60 or 80°C) + 1.5h of cooling down to room temperature. Ethyl and butyl acetate are tested and showed that 38 or 27% of material are solubilized respectively. Toluene seems to be a suitable solvent for pcr-PC / ABS separation. However, ABS ratio in PC / ABS bends are generally located between 15 and 30%. As it is thought that both toluene and ethyl acetate may solubilize a part of PC, butyl acetate was selected for the following study. Table 11: Ratio of material extracted by solubilization from pcr-PC / ABS. * Only 2h mixing as there was no need of cooling down.

[0134] After precipitation, FTIR and DSC analyses showed that the solubilized material is ABS in majority while the non-solubilized material is PC. FTIR analyses (Figure 16) showed an increase of the CN stretch band at 2236 cm-1and of the vinyl stretches above 3000 cm-1(PB) for the recovered material from acetate solution. No such stretch is observed for insoluble materials. However, the major characteristic PC bands

[0029] are observed at 1770, 1222, 1189 and 1160 cm-1in the recovered material from the solution. Moreover, two Tg are observed for the soluble material: one major at 109°C and a minor at 120°C (Figure 17 – recovered ABS – no extra filtration), meaning that some PC is still contained in the recovered ABS. Indeed, when looking at the mixture after a 2h settlement, a fine powder is observed at the bottom of the reactor.

[0135] In order to remove most of the PC from the final recovered ABS, the ABS mixture in butyl acetate was filtrated with several filter in a raw, the finest having pores of 40µm. Looking at the DSC (Figure 17 – recovered ABS – filtration 40µm), only one well defined Tg at 106°C is observed. However, some PC stretches were still visible in the FTIR spectrum of the recovered material, although it was half as intense as in the previous recovered material (Figure 18, see at 1770 cm-1).

[0136] The reduction in pore size caused the filter to block, leading to settlement as another separation technique. PC particles being heavier (around 1,20 g / cm3) than the butyl acetate mixture, the settling time did not exceed 2h. The supernatant containing the ABS was collected and methanol (7 volume equivalent) was added to crash out the ABS. DSC analysis showed a unique and well defined Tg at 103°C (Figure 17) assessing a purer ABS. Moreover, only very little PC stretches are observed in the final material, supporting the recovery of a suitable ABS material (Figure 18).

[0137] Finally, the Tg of all material from the extraction of ABS from pcr-PC / ABS blend shows that two pure materials (PC and ABS) were obtained from the initial blend. Indeed, the initial PC / ABS had a Tg of 129°C while the insoluble material has a Tg of 144°C, in the range of polycarbonate materials (Figure 19). The Tg of recovered ABS were presented before. FTIR spectrum does support this observation as well (Figure 20).

[0138] All methods defined herein take advantage of the degradation of, mainly, C(sp2)=C(sp2) bonds over time that allowed scission of polymeric chains and / or the creation of reactive chemical moieties (radical, oxygenated moieties).

[0139] The results presented in the examples herein show that the polybutadiene phase of rubber containing pcr-resins (e.g., ABS) can be extracted by liquid / liquid extraction. Pigments are extracted as well with this technique. The influence of organic solvent of liquid / liquid extraction was highlighted with increasing extraction by decreasing water solubility. Experiments with virgin ABS showed that it was not possible to extract anything from the resin through a liquid / liquid extraction process. This process can be applied for pcr-HIPS resins with less success.

[0140] In another solubilization / precipitation process, it was highlighted that adding a polyreactive chemicals at different loadings can help pcr-resins to recover its mechanical properties due to the reaction with chemical moieties created from degradation. Polyreactive chemicals are reported to be inactive on virgin ABS while active again when applied on aged virgin ABS. Surprisingly, this method does not work accordingly for pcr-HIPS (with presented examples).

[0141] Then, after preparing a solution of pcr-resins containing rubber, it was shown that partial precipitation can remove a part of non-rubber resin (ex: SAN from ABS) leading to high rubber-content pcr-resins. The process is not as effective for virgin ABS.

[0142] Finally, selective solubilization of pcr-blends showed that it was possible to separate the two pcr- resins from the initial pcr-blend. An example with pcr-PC / ABS has been shown.

[0143] All methods presented herein yields of recovered pcr-resins around 95% at lab scale, after removing insoluble impurities. All methods allowed the removal of additives of all kinds (halogenated, phosphorated and other organic and mineral substances). All methods allowed the separation of soluble pcr-resins from insoluble pcr-resins that were present after mechanical recycling. Example 5 – Chem-Physical Process For Purification And Mechanical Properties Improvement Of Pcr Resins Comprising Carbon-Carbon Double Bonds

[0144] The present technology relates to a process for the purification of Post Consumer Resins (PCR) resins containing carbon-carbon double bonds. The process is intended to scale-up the laboratory experiments described previously in Examples 1, 2 and 3.

[0145] The process relates to a general industrial route to recycle Post Consumer Resins (PCR) thermoplastics containing carbon-carbon double bonds such as Acrylonitrile Butadiene Styrene terpolymer (ABS) and High Impact PolyStyrene (HIPS). The process allows access to four different grades of final recycled resins: high impact ABS, low and high rubber content ABS and SAN (Styrene AcryloNitrile) resins. In order to reach these four grades, the process comprises a solubilization step, followed by a filtration step followed by a precipitation step followed by drying and extrusion of recycled resins. The process comprises optional steps of liquid / liquid extraction and / or selective precipitation steps. Figure 21 is a general scheme of the process.

[0146] First, solvent and a reactive chemical are added in a double envelope reactor equipped with an adapted agitator for heating. When the liquid mixture is heated at the desired temperature, PCR resins are added in the flakes, pellet or powder form through a solid conveyer. After complete dissolution of the soluble resin, the mixture follows a continuous process (Figure 22). The mixture goes through a two-step liquid / solid separation process: the first step to remove large insoluble particles (mm to cm size) and the second step to remove thinner particles (about 0.01-0.1mm). While insoluble impurities are dried and recovered for other uses not described in this process, the liquid mixture is then going to a precipitation step with the use of anti-solvent. For this step, an in-line dynamic mixer is used.

[0147] A specific volumic ratio between the polymer solution and the anti-solvent is controlled by centrifugal pumps placed before the in-line dynamic mixer. This ratio is defined by previous experiments in laboratory. The anti solvent is added at the level of the mixer to allow the formation of a suspension of thin particles. If added before or after, large polymer particles (>0,5cm) is to be obtained that may clog the pipes (Figure 23). The ratio is 7 to 1 between anti-solvent (methanol) and solvent (ethyl acetate). In some instances, the ratio is 5 to 1 between methanol and ethyl acetate is used. After the precipitation step, liquid and solid phases are separated with an appropriate continuous separator. The liquid phase is treated in order to: 1- Separate soluble additives that were extracted from PCR-resins from solvent and anti-solvent; and 2- Separate solvent and anti-solvent through distillation process.

[0148] Extracted additives covers banned brominated flame retardant such as poly brominated diphenyl ether (PBDE), polybrominated biphenyl (PBB), tetrabromobisphenol A (TBBPA) or other halogenated additives such as polyfluoroalkyl substances (PFAS) or chlorinated additives. It also covers soluble phenolic or phosphinated antioxidant. The process also allows to extract volatile organic compounds (VOC) such as, but not only, aromatics molecules: benzene, toluene, styrene, ethyl benzene, and their oxidized counterparts.

[0149] The pcr-resin powder is washed several times with anti-solvent and then dried at room temperature (compressed air or vacuum dried). The temperature should remain low to avoid degradation of pcr-resin that are almost additive free after the process. The maximum allowed temperature is 60°C. Working at 25°C is the optimal choice.

[0150] When the pcr-powder is dry enough (below 200ppm of for both solvent and water), it can be processed by extrusion where extra additives can be added. The parameters and additive are chosen depending on the recycled resin and its quality. Recycled resins are finally obtained as pellets and can be further dried and stored.

[0151] Example of equipment’s that may be used for a 100kg batch process, include but are not limited to: - 3m3storage vessel for ethyl acetate; - 21m3storage vessel for methanol; - 0.5m3storage vessel for the reactive chemical; - 1m3double envelop reactor; -Solid / liquid separator: continuous centrifugal separator;- Centrifugal spray dryer for insoluble impurities;- In-line dynamic mixer for precipitation; -Solid / liquid separator: continuous centrifugal separator;- Centrifugal spray dryer for recovered resins;- Double screw extruder with side feeder for additives additions. Equipped with pelletizer;- Storage for pelletized recycled PCR resins;- A boiler to separate solvent from extracted additives; and - Distillation column equipped with condenser and reboiler to recover ethyl acetate from methanol.

[0152] In order to access several pcr-resin quality, optional steps can be added to the process of the present technology. The addition of a liquid / liquid extraction step after the first liquid / solid separation allows the rough separation of SAN and rubber from pcr-ABS. After the addition of, for example, one equivalent of a non-miscible aqueous phase (e.g. water) to the organic phase containing the solubilized resin followed by a strong mixing, a two phases mixture is obtained. After settling down, the two phases need to be separated by liquid / liquid separation. Then, both liquid phases (organic and aqueous) can be re-introduced into the process at the precipitation step. The other steps of the process are then followed. Low and high rubber content are obtained from an initial feedstock of pcr-ABS (Figure 24).

[0153] List of equipment for this optional step: - An extraction column for the liquid / liquid extraction and decantation

[0154] Selective precipitation is used to access new grades of recycled resins with ABS. Addition of low amount of anti-solvent allows the precipitation of only one part of the ABS: high rubber content ABS. In one embodiment, the ratio between anti-solvent and solvent can be of 0.6. For other properties, the ratio can be adjusted to 0.5. In this way. Part of the free SAN phase of ABS remains in solution and can be further precipitated afterwards. That is why an optional precipitation step can be added after the 2nd liquid / solid separation step with usual anti-solvent / solvent ratio described previously (5 or 7). Another liquid / solid separation step needs to be added as well. The liquid phase from this later is going through treatment process while the solid phase is going back to the main process at the washing step (Figure 25).

[0155] List of extra equipment: - In-line dynamic mixer for 2ndprecipitation; and - Solid / liquid separator: continuous centrifugal separator.

[0156] The process of the present technology allows to extract banned additives from the initial resin. Banned additives covers brominated flame retardant such as poly brominated diphenyl ether (PBDE), polybrominated biphenyl (PBB), tetrabromobisphenol A (TBBPA) or other halogenated additives such as polyfluoroalkyl substances (PFAS) or chlorinated additives. The process also allows to extract volatile organic compounds (VOC) such as harmful aromatics molecules such as, but not limited to, benzene, toluene, styrene, and ethyl benzene.

[0157] While most of them are extracted by the one solubilization / precipitation step, further extraction may be needed in order to respect most restrictive standards (RoHS, customers). In classic general chemistry, when it comes to purifying a solid from soluble impurities, the most commonly used method involves solubilising the solid and precipitating the desired material several times with an anti-solvent to extract most of the unwanted impurities. The same principle is used in this process. After the second liquid / solid extraction, the ‘wet’ solid resin can be re-injected for further solubilisation / precipitation steps until the required standards are achieved.

[0158] All references cited in this specification, and their references, are incorporated by reference herein in their entirety where appropriate for teachings of additional or alternative details, features, and / or technical background.

[0159] While the disclosure has been particularly shown and described with reference to particular embodiments, it will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also, that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.

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Claims

CLAIMS:

1. A method for recovering resins from rubber-based post-consumer recycled resins, the method comprising one or more of: a) removing a rubber phase from the rubber-based post-consumer recycled resins by liquid-liquid extraction; b) solubilizing and precipitating the rubber-based post-consumer recycled resins using polyreactive chemicals; c) performing sequential precipitation of the rubber-based post-consumer recycled resins to obtain high rubber-content resin and rubber-free resin; and d) performing selective solubilization of the rubber-based post-consumer recycled resins to allow separation of resins from the rubber-based post-consumer recycled resins.

2. A method for recovering resins from rubber-based post-consumer recycled resins, the method comprising: a) solubilizing the rubber-based post-consumer recycled resins in an organic solvent to obtain solubilized rubber-based post-consumer recycled resins; b) filtering the solubilized rubber-based post-consumer recycled resins of step a) to remove insoluble impurities; and c) performing liquid-liquid extraction of rubber content resin from the solubilized rubber - based post-consumer recycled resins with a polar solvent such that low rubber content resins are found in an organic phase and high rubber content resins are found in a polar phase.

3. The method of claim 2, wherein the polar solvent is a non-miscible protic polar solvent.

4. The method of claim 3, wherein the polar solvent is water or ethylene glycol.

5. The method of any one of claims 2 to 4, further precipitating the low rubber content resins from the organic phase and the high rubber content resins from the polar phase.

6. A method for recovering resins with improved mechanical properties from rubber-based post- consumer recycled resins, the method comprising: a) solubilizing the rubber-based post-consumer recycled resins in a solvent comprising a reactive chemical;b) filtering the solubilized rubber-based post-consumer recycled resins to remove insoluble impurities; and c) precipitating the filtered solubilized rubber-based post-consumer recycled resins to obtain a rubber-based resins with improved mechanical properties.

7. The method of claim 6, wherein the reactive chemical is a molecule comprising at least one chemically active moiety.

8. The method of claim 7, wherein the chemically active moiety is an alcohol, a thiol, an amine, a carboxylic acid, an aldehyde, an alkene or a mixture thereof.

9. The method of claim 6, wherein the reactive chemical is Ethanol, Ethylene glycol, Propylene glycol, 2,3-butanediol, 1 ,6-hexanediol, Hydroquinone, Glycerol, Trimethylolethane, Triethanolamine, Pentaerythritol, Quadrol, Dodecanethiol, 1 ,6-hexanedithiol (1,6-HDT), 2,2'-Thiodiethanethiol, TP3MP, PT4MP, 1,6-hexamethylene diamine, Acetic acid, Adipic acid, Terephtalic acid, p-toluenealdehyde, Terephtalaldehyde, 1 -hexene, 1-octene, 1 ,5-hexadiene, 1,7-octadiene, Diethylene glycolamine, Tris, or a mixture thereof.

10. A method for recovering resins from rubber-based post-consumer recycled resins, the method comprising: a) solubilizing the rubber-based post-consumer recycled resins in a solvent; b) filtering the solubilized rubber-based post-consumer recycled resins to remove insoluble impurities; c) performing partial precipitation of the solubilized rubber-based post-consumer recycled resins to extract high rubber-content resins; and d) separating the high rubber-content resins from the solvent.

11. The method of claim 10, further comprising precipitating rubber free resin from the solvent.

12. A method for recovering resins from blends containing rubber-based post-consumer recycled resins, the method comprising: a) solubilizing the rubber-based post-consumer recycled resins from a pcr-blend in a solvent that solubilizes only the rubber-based resin;b) filtering the solubilized rubber-based post-consumer recycled resins to remove insoluble material; and c) performing precipitation to recover the solubilized rubber-based post-consumer recycled resin.

13. The method of claim 12, wherein the solvent that solubilizes only a rubber-based resin is acetates , methyl ethyl ketone, or toluene.

14. The method of any one of claims 1 to 13, wherein the rubber-based post-consumer recycled resins are Acrylonitrile Butadiene Styrene terpolymer (ABS), High Impact Polystyrene (HIPS), blends of PolyButadiene (PB) or Styrene Butadiene Styrene terpolymer (SBS) or Ethylene Propylene Diene Monomer terpolymer (EPDM) or Nitrile Butadiene Rubber (NBR) or other rubber with thermoplastics such as Polypropylene (PP), Polycarbonate (PC), Polystryrene (PS), Styrene Acrylonitrile (SAN), PolyMethylMethAcrylate (PMMA), PolyVynilChlorine (PVC) or a mixture thereof.

15. A method for purification of Post Consumer Resins (PCR) resins containing carbon-carbon double bonds to obtain a recycled PCR resin, the method comprising: a) solubilising a PCR resin to obtain a solubilized PCR resin; b) removing solid impurities from the solubilized PCR resin; c) precipitating the solubilized resin of step b) to obtain solid PCR resin in a liquid phase; d) removing precipitated solid from the liquid phase of step c) to obtain a solid recycled PCR resin; and e) drying the recycled PCR resin of step d).

16. The process of claim 15, further comprising performing after step b) a step of liquid / liquid extraction of the filtrated solubilized resin.

17. The process of claim 15 or 16, further comprising performing after step d) a precipitation of a liquid phase obtained in step d).

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