[go: up one dir, main page]

WO2025120155A1 - Procédé de production d'un polymère de polychlorure de vinyle (pvc) - Google Patents

Procédé de production d'un polymère de polychlorure de vinyle (pvc) Download PDF

Info

Publication number
WO2025120155A1
WO2025120155A1 PCT/EP2024/085072 EP2024085072W WO2025120155A1 WO 2025120155 A1 WO2025120155 A1 WO 2025120155A1 EP 2024085072 W EP2024085072 W EP 2024085072W WO 2025120155 A1 WO2025120155 A1 WO 2025120155A1
Authority
WO
WIPO (PCT)
Prior art keywords
pvc
solvent
process according
chelating agent
dissolution
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2024/085072
Other languages
English (en)
Inventor
Eric Romers
Corentin Dubois
Loris PANARISI
Florent MINETTE
Jean-Christophe Lepers
Jean-Philippe Dumont
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Inovyn Europe Ltd
Original Assignee
Inovyn Europe Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Inovyn Europe Ltd filed Critical Inovyn Europe Ltd
Publication of WO2025120155A1 publication Critical patent/WO2025120155A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/06—Recovery or working-up of waste materials of polymers without chemical reactions
    • C08J11/08—Recovery or working-up of waste materials of polymers without chemical reactions using selective solvents for polymer components
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2327/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers
    • C08J2327/02—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment
    • C08J2327/04—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers not modified by chemical after-treatment containing chlorine atoms
    • C08J2327/06—Homopolymers or copolymers of vinyl chloride

Definitions

  • the present invention relates to a process for purification of polyvinyl chloride (PVC) polymer, and in particular with efficient removal of metals present.
  • PVC polyvinyl chloride
  • PVC polyvinyl chloride
  • additives including mineral fillers, thermal stabilisers and plasticisers.
  • thermal stabilisers based on lead and cadmium, and plasticisers such as di (2- ethylhexyl) phthalate (DEHP), dibutyl phthalate (DBP) and benzyl butyl phthalate (BBP), which were historically used are now subject to restrictions on their use in "new" PVC but also their presence in recycled PVC.
  • DEHP 2, 2- ethylhexyl
  • DBP dibutyl phthalate
  • BBP benzyl butyl phthalate
  • WO 2006/069856 describes the use of a base or dispersing agent to remove heavy metals, and in particular lead and cadmium.
  • WO 2006/053907 describes use of an additive capable of absorbing or forming complexes with the compound of the heavy metal, and in particular describes use of magnetite or EDTA to remove lead and cadmium.
  • a process for removing metals from a PVC composition comprising a PVC resin and one or more stabilisers comprising metal compounds, which process comprises dissolution of the PVC in a solvent or mixture of solvents and contacting of the solution of PVC with a chelating agent, wherein the chelating agent is an organic acid selected from:
  • the present invention relates to removal of metals from a PVC composition. Removal of metals from a PVC composition is generally desired when seeking to recycle a PVC composition.
  • avy metals refers to metals which have, in the metallic form, a density of at least 5 g/cm 3 .
  • the metals, including heavy metals, to be removed are usually added to the PVC composition in the form of metal compounds added as additives.
  • the metals removed in the present invention are removed in the form of ions, and in particular as a complex of the chelating agent and the metal ion.
  • the chelating agents are effective in removing the metals from the PVC composition, and the requirement of the present invention that metals are removed is not intended to denote that they are removed in any specific form.
  • PVC resin a pure PVC is generally referred to as "PVC resin".
  • PVC resins are not used in their pure form, however, but mixed with a variety of additives.
  • additives as well as the (base) PVC resin, are generally selected based on the application for which the PVC is to be used, but common additives include plasticisers, mineral fillers and thermal stabilisers.
  • the formulated mixture of PVC resin and additives is typically referred to as a "PVC compound" or "PVC composition”.
  • PVC composition we use the term "PVC composition” to refer to such a mixture of PVC resin and additives, and in particular where the additives include one or more stabilisers comprising metal compounds.
  • the PVC composition may also comprise significant quantities of other additives.
  • a typical PVC composition for a flexible application such as artificial leather, cable or flooring applications
  • plasticisers all or some of which may be phthalates
  • other additives such as fillers, in addition to the PVC resin component and the stabilisers.
  • PVC polymer refers to the product obtained after removal of metals from the PVC composition.
  • this may in theory be a PVC resin, but more usually the "PVC polymer” obtained will be a mixture comprising PVC resin and some residual additives, such as plasticisers.
  • the PVC composition used in the present invention may comprise PVC recycled from any suitable source. It may, for example, comprise PVC which has been physically separated from household or industrial waste. Preferably the PVC composition is obtained by recycling of PVC previously used for a particular application. For example, PVC is commonly used for window frames and profiles, and the PVC composition may therefore be or be derived from waste PVC window profiles. Another common use of PVC is in wire and cable applications. Thus, the PVC composition may be waste wire and cable or derived from waste wire and cable, for example by separating the PVC composition from the metal wire. Other sources of the PVC composition include membranes, tarpaulins, textiles and other coated fabrics, PVC flooring, vinyl wallpaper, flexible hoses and numerous automotive applications.
  • the PVC resin and the additives in the composition will be of a consistent and similar type. Most usefully, however, this means that the resulting purified PVC polymer will also then be generally suitable for reuse in the same application or in other specific applications which require similar PVC properties.
  • the PVC composition prior to the dissolution is in the form of lumps, strips, flakes or chips, for example obtained by grinding, shredding, cutting or chopping of larger forms of product.
  • An example would be, for example, cut window profiles or PVC cable.
  • the PVC composition in this mixture and typically the mixture as a whole, more usually has an average particle size in the range of several millimetres to tens of millimetres, for example 5 to 80mm, with particle sizes of 5 to 25mm most usual.
  • Non-PVC components which as defined herein refers to components which are other than those typically found in a PVC composition, may be present.
  • Non-PVC components may, for example, comprise polyolefins and polymers other than PVC or polyolefins. These may be present, for example, because the PVC composition was used in an application with another polymer or as "contaminants" from the PVC collection and sorting process.
  • the PVC composition is relatively “pure" of components other than those typically found in a PVC composition i.e. other than PVC resin, the stabilisers/metal compounds and other PVC additives which were originally added to the PVC composition for its intended use.
  • the PVC composition may have been, and preferably has been, obtained after treatment of an initial mixture comprising the PVC composition and other components, for example a mixed polymer stream or a stream comprising PVC and metals, such as copper, obtained from wire and cable scrap, to remove such components or any other foreign contaminant.
  • the PVC composition constitutes at least 90wt% of the total solids which are contacted with and dissolved in the solvent, such as at least 95wt%, and more preferably at least 98wt% i.e. if there are components which are other than those typically found in a PVC composition, they are present in a maximum amount of no more than 10wt%, preferably no more than 5wt% and more preferably no more than 2wt%. In preferred embodiments, there is less than 1 wt% polymers other than PVC present.
  • compositions may be obtained by treating, such as physical separation, of an initial mixture comprising the PVC composition to remove other components, such as other polymers.
  • the PVC composition prior to the dissolution and contacting steps, comprises at least lwt% of metal compounds, and more generally, comprises at least lwt% of heavy metal compounds.
  • the PVC composition prior to the dissolution and contacting steps, comprises at least lwt% fillers.
  • the metal/heavy metal compounds and fillers present would largely or exclusively be due to components which are considered part of the PVC composition as such a composition is defined herein, and not "components which are other than those typically found in a PVC composition" discussed above.
  • the heavy metal compounds present may, in particular, be largely or exclusively due to thermal stabilisers added to form the PVC composition.
  • the present invention comprises dissolution of the PVC in a solvent or mixture of solvents.
  • a solvent or mixture of solvents capable of dissolving at least the PVC resin component of the PVC composition may be used for this step.
  • suitable solvents include hydrocarbons, such as ketones, and in particular methyl ethyl ketone.
  • a preferred solvent for the present invention is a mixture of solvents, and in particular a mixture of a ketone, an alcohol and an alkane, for example a mixture of methyl ethyl ketone (MEK) with hexane, isopropanol and water.
  • a particularly preferred solution comprises between 2% and 8% by weight of alcohol, preferably iso-propanol, between 13% and 17% of alkane, preferably isohexane, between 4% and 6% of water, and the remainder (namely between 69% and 79% by weight) being a ketone, preferably methyl ethyl ketone.
  • the dissolution forms a solution of PVC in the solvent or mixture of solvents.
  • the solution of PVC is contacted with a chelating agent.
  • the chelating agent may be added at any suitable time.
  • PVC composition may dissolve in the solvent or mixture of solvents.
  • some solids may, and usually will, be present in the solution of PVC obtained.
  • a particular advantage of the present invention is that it is not necessary to filter the solution of PVC obtained after dissolution of the PVC in the solvent to remove such solids prior to the step of contact of the solution of PVC with the chelating agent.
  • the chelating agent may be present in the solvent or mixture of solvents prior to the dissolution of the PVC in the solvent or mixture of solvents.
  • the dissolution of the PVC in the solvent or mixture of solvents is performed first, and the chelating agent is added to the solution of PVC after this.
  • the addition of the chelating agent may be performed after the dissolution and before any other treatment or process steps (such as filtering as noted). In some embodiments, however, chelating agent may be added during subsequent process steps, such as the precipitation of dissolved PVC. This is described further below.
  • the dissolution of the PVC may be performed at any suitable temperature and pressure.
  • an elevated temperature such as a temperature in the range 90 to 120°C is preferred.
  • ambient pressure can be used, elevated pressure is generally used at temperatures above the boiling point of the solvent or solvent mixture used.
  • the dissolution can be performed in any suitable manner. Typically stirring is applied to assist in the dissolution step.
  • the contacting of the solution of PVC and the chelating agent may also be performed at any suitable temperature. This step is preferably performed at a temperature in the range 90 to 120°C. Whilst ambient pressure can be used, elevated pressure is preferred. Most preferably the contacting of the solution of PVC and the chelating agent is performed at or close to the temperature and pressure used for dissolution. (And hence if the chelating agent is added after dissolution, the temperature and pressure can be largely maintained between the steps.)
  • the contacting time of the solution of PVC and the chelating agent may generally be from 5 to 120 minutes.
  • the amount of chelating agent used is selected to be in excess of the amount of metals to be removed.
  • an amount of 1 to 5wt% based on the mass of the PVC composition is suitable.
  • purified PVC polymer (PVC polymer without metal compounds or with reduced amounts of metal compounds) can be obtained by precipitation of the dissolved PVC polymer from the solution in the solvent or mixture of solvents.
  • the process of the present invention comprises steps of: i. dissolution of the PVC in the solvent or mixture of solvents; ii. contacting of the solution of PVC with the chelating agent: and ill. precipitation of PVC polymer from the solution.
  • the chelating agent (a) may be present in the solvent or mixture of solvents used for the dissolution or added during the dissolution, (b) may be contacted with the solution of PVC after dissolution but prior to precipitation, or (c) may be added to the solution during the precipitation step.
  • a combination of two or more of these may also be used i.e. chelating agent may be present/added in more than one of these steps.
  • one advantage of the process of the present invention is that it is not necessary to filter the solution of PVC obtained after dissolution of the PVC in the solvent to remove solids which are insoluble prior to the step of contact of the solution of PVC with the chelating agent.
  • the process of the present invention comprises dissolution of the PVC in a solvent and contacting of the solution of PVC with the chelating agent without filtration of the solution of PVC in the solvent to remove solids compounds prior to the contact of the solution of PVC with the chelating agent.
  • a filtration or other solids separation step may be applied after the dissolution of the PVC in the solvent to remove insoluble solids before contact of the solution with the chelating agent.
  • the process of the present invention comprises steps of: i. dissolution of the PVC in the solvent or mixture of solvents; ii. contacting of the solution of PVC with the chelating agent: iii. removal of solids compounds from the product mixture obtained after contacting of the solution of PVC with the chelating agent; and iv. precipitation of PVC polymer from the solution.
  • the removal of solids compounds from the product mixture obtained after contacting of the solution of PVC with the chelating agent in this embodiment may be performed by any suitable technique. Most preferably this step is performed using a centrifuge.
  • Precipitation of PVC polymer can be obtained by injection of steam, and optionally liquid water, into the solution of the PVC to precipitate the PVC and remove the solvent.
  • the liquid water when used, may be in the form of an aqueous phase containing solvent, such as a ketone, recovered from an earlier precipitation step). The removal of the solvent gives rise to the precipitation of the PVC polymer.
  • the solvent comprises a polar aprotic organic solvent (PAOS) that has an azeotrope with water, a polar organic compound that is miscible with the PAOS and immiscible with water and that acts as a phase separation agent (PSA), and an alcohol.
  • PAOS polar aprotic organic solvent
  • PSA phase separation agent
  • precipitation is performed from a mixture of solvents comprising a mixture of a ketone, an alcohol and an alkane, for example a mixture of methyl ethyl ketone (MEK) with hexane, isopropanol and water.
  • a particularly preferred mixture of solvents for the precipitation step comprises 2% and 8% by weight of alcohol, preferably iso-propanol, between 13% and 17% of alkane, preferably isohexane, between 4% and 6% of water, and the remainder (namely between 69% and 79% by weight) being a ketone, preferably methyl ethyl ketone.
  • One or more dispersing agents may be added during the precipitation.
  • one or more dispersing agents may be used during the precipitation, and preferably to use both a primary dispersing agent and a secondary dispersing agent.
  • the addition of dispersing agents can provide particles which are particularly suitable for further treatment where required, such as to remove plasticisers as discussed further below.
  • dispersing agents are known in the art. It is generally preferred that as at least one dispersing agent is present when the precipitation starts.
  • Typical dispersing agents include surfactants, such as bentonite, polyvinyl alcohol, gelatin, cellulose esters or ethers and water-soluble (co) polymers.
  • the one or more dispersing agents, when used, are typically used in an amount generally greater than or equal to 0.01%, preferably greater than or equal to 0.1% by weight relative to the weight of PVC.
  • the amount of dispersing agent is generally less than or equal to 5%, or less than or equal to 2%, or less than 1% by weight relative to the weight of PVC. It is preferred that at least one partially hydrolysed polyvinyl alcohol is used as a dispersing agent.
  • the dispersing agents are advantageously chosen from cellulose ethers and polyvinyl alcohols. Most preferably both the primary and second dispersing agents are polyvinyl alcohols but having differing levels of hydrolysis.
  • the primary dispersing agent may be a partially hydrolysed polyvinyl alcohol which is at least 65% hydrolysed, such as at least 70% hydrolysed.
  • the primary dispersing agent may be less than or equal to 90%, such as less than or equal to 80% hydrolysed. It is preferably from 65% to 90% hydrolysed, and more preferably from 70 to 80% hydrolysed.
  • the second dispersing agent may be a partially hydrolysed polyvinyl alcohol with of hydrolysis than the primary dispersing agent, such as being less than or equal to 60% hydrolysed, such as less than or equal to 55% hydrolysed.
  • the secondary dispersing agent is preferably from 25 to 55%, such as from 30 to 50% hydrolysed.
  • the chelating agent added for the precipitation step may be the same or different to that used in the earlier contacting step. It is generally preferred however that it is the same.
  • the chelating agent, when present in the precipitation step is typically added after a step of removal of solids compounds formed from the earlier contacting step, such as described above, and either before or during the precipitation step itself.
  • the precipitation step generally removes' all organic solvents present and results in precipitated PVC polymer solids in an aqueous phase.
  • the PVC polymer solids can be separated from the aqueous phase, for example by filtration or using a centrifuge, and dried, to provide a PVC polymer.
  • a chelating agent is present during the precipitation step then the chelating agent, and complexes of the chelating agent with metals removed from the PVC, are generally soluble in the aqueous phase.
  • the polymer solids can, and typically would, be further treated, not least to remove plasticisers if present. It is also within the scope of the invention to treat the precipitated PVC polymer solids before or without separation from the aqueous phase.
  • the chelating agent is an organic acid selected from:
  • acids having 1 to 3 carboxylic acid groups optionally with at least one separate hydroxyl group, a separate hydroxyl group being a hydroxyl group which is not part of a carboxylic acid group.
  • the chelating agent is ascorbic acid.
  • the chelating agent is an organic acid having 1 to 3 carboxylic acid groups, optionally with at least one separate hydroxyl group, a separate hydroxyl group being a hydroxyl group which is not part of a carboxylic acid group. It is preferred in this embodiment that there is at least one, preferably 1 or 2, separate hydroxyl groups, i.e. it is preferred that the organic acid has 1 to 3 carboxylic acid groups and at least one, preferably 1 or 2, separate hydroxyl groups.
  • the organic acids in this second embodiment are generally "weak acids". It is preferred that the organic acids in this second embodiment have a pKa (or first pKa where more than one acid groups are present) which is at least 1, more preferably at least 2, such as at least 2.5. Most preferably the pKa (/first pKa) is at least 3. The pKa is typically, and preferably, less than 10, such as in the range 3 to 7.
  • ascorbic acid has a pKa of 4.17, so also falls within these preferred ranges.
  • the total number of carboxylic acid and separate hydroxyl groups in the organic acid is no more than 4.
  • the organic acid has 2 to 6 carbon atoms.
  • Particularly preferred organic acids in this embodiment are citric acid, tartaric acid and lactic acid. It has been found that the selected chelating agents are effective at removing lead and cadmium.
  • the PVC polymer obtained after the dissolution and contacting steps comprises less than 200ppm, preferably less than lOOppm, of each of Pb and Cd. Yet more preferably, the PVC polymer obtained after the dissolution and contacting steps comprises less than 20ppm, preferably less than lOppm, of each of Pb and Cd.
  • the selected chelating agents are effective at removing metals other than lead and cadmium.
  • the selected chelating agents have been found to be effective at removing metals associated with some of the additives which are typically present, and in particular, titanium and barium.
  • the selected chelating agents are also effective at removing metalloids, such as boron, silicon, arsenic and antimony.
  • the PVC polymer obtained after the dissolution and contacting steps comprises less than 200ppm, preferably less than lOOppm, of each of Pb, Cd, Ti, Ba, Si, Sb, As, B, Sr and Zn.
  • the PVC polymer obtained after the dissolution and contacting steps comprises less than lOOOppm, preferably less than 500ppm, of heavy metals in total. Most preferably, the PVC polymer obtained after the dissolution and contacting steps comprises less than lOOOppm, preferably less than 500ppm, of heavy metals and metalloids in total.
  • the organic acids selected can not only efficiently remove lead and cadmium, but also other metals, including other heavy metals, and also metalloids present.
  • compounds of titanium are often present due to the presence of pigments in the PVC composition.
  • barium this can be present from additives added as flame retardants.
  • the selected organic acids can remove not only the stabiliser metals but also these others.
  • the process of the present invention can also remove some non-metallic compounds from a PVC composition.
  • bromine compounds such as polybrominated phenyl ethers, are removed during the process of the present invention.
  • Polybrominated diphenyl ethers are another compound known to be used as flame retardants, for example.
  • the obtained precipitated PVC polymer may be treated to remove the plasticisers.
  • the PVC polymer contacted with a solvent in which the one or more plasticisers are soluble but in which the PVC resin is insoluble to form a slurry, said slurry comprising PVC polymer solids and dissolved plasticisers, followed by a step of separating the PVC polymer solids to obtain purified PVC polymer solids.
  • the solvent for this step may be any suitable solvent in which the one or more plasticisers are soluble but the PVC resin is insoluble.
  • suitable solvents suitable for this step include, generically, CO2, alkanes, alcohols, esters and ethers.
  • the precipitated PVC polymer is obtained in the form of particles with a D50 of less than 600 microns and a sphericity of at least 0.7.
  • the particles are, thus, both relatively small and also of uniform shape.
  • a relatively small particle size and uniform shape is advantageous for subsequent treatment to remove plasticisers and other additives present, and in particular, enables the solvent to extract plasticisers efficiently from throughout the particles of the PVC composition, allowing PVC polymer solids with low levels of residual plasticisers to be efficiently obtained.
  • the precipitated PVC polymer is in the form of particles having a D50 of at least 50 microns, such as at least 100 microns.
  • the D50 is preferably less than 500 microns, with a D50 in the range of from 250 to 450 microns being most preferred.
  • the D90 is less than 800 microns and/or the D95 is less than 1000 microns.
  • D50, D90 and D95 refer to the points on the particle size distribution curve below which 50%, 90% and 95% respectively by number of the particles are found.
  • Particle size distribution may be determined by a suitable measuring device or sieves, for example according to ASTM D1921- 18 "Standard Test Methods for Particle Size (Sieve Analysis) of Plastic Materials".
  • the sphericity of a particle is a measure of how closely the shape of the particle resembles that of a perfect sphere.
  • the sphericity is defined as the median aspect ratio ("S50 aspect ratio"), where the aspect ratio of a particle is the ratio of the minimum FERET diameter (d Fmin ) to the maximum FERET diameter (d Fmax ).
  • S50 aspect ratio the median aspect ratio
  • a FERET diameter is a measure of the distance between two parallel tangents located on opposite sides of a cross-section of a particle. For a sphere the value is 1 since the diameter is the same in all orientations.
  • the FERET diameter varies with the orientation of the tangents.
  • the maximum FERET diameter is the largest possible measurement and the minimum FERET diameter is the smallest possible measurement. This is illustrated for an example particle shape in Figure 1.
  • the sphericity in the present invention is defined as the median or S50 aspect ratio, and is the value obtained by plotting a cumulative curve of number of particles versus aspect ratio, and determining the aspect ratio of the median particle.
  • the sphericity may be determined from particle cross-sections by analysis of an image, such as a photo, of a representative selection of the particles, for example 200 to 1000 particles, using commercially available software.
  • the measurement of the particle shape and calculation of the sphericity are performed by commercially available analysers designed for such purposes. These may include taking images and using suitable software or using techniques such as laser diffraction for the analysis.
  • An example of a suitable system would include the Sympatec QICPIC analyser and its associated software.
  • the precipitated PVC polymer is preferably in the form of particles having a sphericity of at least 0.72, such as at least 0.75 or at least 0.80.
  • the sphericity is generally less than 1 (rather than 1), for example in the range 0.75 to 0.95.
  • the contacting with a solvent in which the one or more plasticisers are soluble but in which the PVC resin is insoluble may be performed under any suitable conditions.
  • the solvent should be in a liquid state during the contacting (such that the extraction of plasticisers is a solid-liquid extraction method).
  • the temperature and pressure in the contacting step should therefore generally be selected such that the solvent is in liquid state and the PVC is in the solid state.
  • an elevated pressure is required for solvents which would be gaseous at room temperature and atmospheric pressure then an elevated pressure is required.
  • the contacting with the solvent in a liquid state may be performed at ambient temperature, although use of an elevated temperature can improve the rate of plasticisers removal, and allow a lower contacting time.
  • the temperature should be selected to make the extraction as efficient as possible.
  • the temperature is preferably in the range 20°C to 120°C.
  • contacting times with solvents where contacting is performed in a liquid state are less than 2 hours in practise, and preferably less than 1 hour. Preferred contacting times are 1 minute to 2 hours, such as 5 minutes to 1 hour.
  • the contacting is preferably performed using supercritical CO2.
  • the temperature and pressure in the contacting step are therefore generally selected such that the CO2 is in the supercritical state and the PVC is in the solid state.
  • Supercritical CO2 generally requires a temperature of at least about 31°C, and a pressure of at least about 7380 kPa (73.8 bar).
  • the temperature for the contacting step when using supercritical CO2 is preferably at least 35°C.
  • the temperature is preferably less than 120°C, preferably less than 80°C, and most preferably in the range 40°C to 80°C.
  • the pressure may be any pressure suitable to maintain the CO2 in a supercritical state. It is preferably at least 7500 kPa, and more preferably at least 10 MPa. There is no particular restriction on the maximum pressure, but generally providing equipment to handle very high pressures is expensive and unnecessary. Hence the pressure is preferably less than 60 MPa, such as less than 40 MPa or less than 30 MPa. Pressures in the range 10 MPa to 20 MPa are most preferred, and more preferably less than but preferably takes place at an elevated temperature as this can improve the rate of plasticisers removal, and allow a lower contacting time. The temperature should be selected to make the extraction as efficient as possible. The temperature is preferably in the range 30°C to 120°C.
  • Contacting time when CO2 is used as the solvent may typically be at least 2 minutes.
  • contacting times where contacting is performed with CO2 in a supercritical state are less than 4 hours in practise, and preferably 3 hours or less. Preferred contacting times are 30 minutes to 2 hours.
  • Contacting of the PVC composition with the solvent may take place in any suitable vessel.
  • This could include a tank, such as a stirred tank, or a column, such as a trayed or staged column.
  • Contacting of the PVC composition with the solvent may be performed as batch reaction/process, but is preferably performed as a continuous reaction/process.
  • PVC polymer solids are separated (from the slurry/dissolved plasticisers) to obtain purified PVC polymer solids.
  • the separation may be by any suitable method for separating solids from a liquid, such as decanting, settling, centrifugation or filtration.
  • the purified PVC polymer solids may be washed if required, for example with water and optionally stripped (at atmospheric pressure or under vacuum) to remove any residual solvent.
  • the purified PVC polymer solids may be dried, for example after a washing step as noted. In other embodiments however, with a solvent which is a gas at room temperature and pressure, such as CO2, the purified PVC polymer solids may be separated from residual solvent simply by allowing vaporisation of the solvent.
  • the solvent comprising dissolved plasticisers after separation of the purified PVC polymer solids, may be treated to precipitate and separate the plasticisers so that the solvent can be recycled and reused in the present invention.
  • the separated plasticisers may comprise phthalate plasticisers but also other non-phthalate plasticisers.
  • the separated plasticisers may be purified, e.g. by hydrogenation, so that they can be reused as plasticisers under EU REACH or similar regulations in other jurisdictions and/or other applications.
  • the PVC composition comprised with 46% PVC resin, 30% plasticizers and 23% fillers.
  • the PVC composition is dissolved in approximately 300 g of methyl ethyl ketone solvent, with stirring and heating at 60°C and at ambient pressure. Except in Comparative Example 1, where no chelating agent was used, approximately 2wt% (based on the weight of PVC composition) of a chelating agent was present in the methyl ethyl ketone solvent. The mixture was heated and stirred at 60°C for approximately 90 minutes to dissolve all of the PVC.
  • the mixture was then centrifuged to separate insoluble compounds from the original PVC composition.
  • the insoluble compounds were dried and recovered.
  • the PVC polymer solids were separated by filtration to leave a residual aqueous phase.
  • the PVC polymer solids are dried at 80°C for 4 hours.
  • Example 6 The procedure of Example 5 was repeated (lactic acid as the chelating agent), except that an additional amount of lactic acid was added with the mixture of iso-hexane, iso-propanol, water and dispersing agent added prior to precipitation.
  • Thermal stability analysis was performed on the obtained PVC polymer solids according to the method of ISO 182-3. It has been found that thermal stability values are correlated with the levels of residual metals, with lower values of thermal stability being indicative of reduced level of metals.
  • Table 2 shows that the use of citric acid results in removal of the heavy metals Pb and Cd, as well as a number of others, to low levels in the obtained PVC polymer solids. The results also show that the metals are found almost exclusively in the insolubles recovered, which is a significant advantage in terms of their disposal, and also allows the aqueous phase to be recycled and reused.
  • Removal of metals is performed on a small scale pilot plant using a PVC composition derived from window frames which had been shredded to particles of about 1cm in dimension.
  • the PVC composition comprised, by weight, 90% PVC resin, 7% fillers and stabilisers and 3% non-PVC impurities.
  • Example 7 300 g of the PVC composition is placed in a dissolving tank.
  • Example 7 there is also added to the dissolving tank 6g of citric acid. This is omitted in the Comparative Example 4.
  • 2500g of a solvent mixture comprising methylethylketone (MEK), iso-hexane, iso-propanol and water which had been pre-heated to 100°C, whilst the solution was stirred at 600rpm to dissolve the PVC composition.
  • the solution was then cooled to 55°C, and then centrifuged for 225 seconds at 2500 rpm to separate solids present.
  • MEK methylethylketone
  • the recovered supernatant (solvent comprising dissolved PVC which has been separated from the solids) was passed to a precipitation tank.
  • the pressure was reduced to 600 mbara and steam was introduced to effect removal of the organic solvents and precipitation of PVC polymer, to leave an aqueous phase comprising precipitated PVC polymer solids.
  • the PVC polymer solids were separated by filtration and dried.
  • the initial PVC composition i.e. before treatment
  • Table 3 shows the results for a number of the metals present.
  • ND not determined (It should be noted that a number of other metals were found to be less than the detection limit in the obtained PVC solids, including the heavy metals Sb, As, Hg, Ni, Fe, Cu, Cr, Mn, Sn. However, these were not analysed for in the initial PVC composition.)

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Macromolecular Compounds (AREA)

Abstract

La présente invention se rapporte à un procédé de production d'un polymère de polychlorure de vinyle (PVC) purifié, et présentant en particulier une élimination efficace de métaux. En particulier, l'invention concerne un procédé d'élimination de métaux d'une composition de PVC comprenant une résine de PVC et un ou plusieurs stabilisants contenant des composés métalliques, ledit procédé consistant en la dissolution du PVC dans un solvant ou un mélange de solvants et la mise en contact de la solution de PVC avec un agent chélateur, l'agent chélateur étant un acide organique choisi parmi : (a) l'acide ascorbique, et (b) des acides comportant de 1 à 3 groupes acide carboxylique, facultativement avec au moins un groupe hydroxyle séparé, un groupe hydroxyle séparé étant un groupe hydroxyle qui ne fait pas partie d'un groupe acide carboxylique.
PCT/EP2024/085072 2023-12-07 2024-12-06 Procédé de production d'un polymère de polychlorure de vinyle (pvc) Pending WO2025120155A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP23214996.3 2023-12-07
EP23214996 2023-12-07

Publications (1)

Publication Number Publication Date
WO2025120155A1 true WO2025120155A1 (fr) 2025-06-12

Family

ID=89121554

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2024/085072 Pending WO2025120155A1 (fr) 2023-12-07 2024-12-06 Procédé de production d'un polymère de polychlorure de vinyle (pvc)

Country Status (1)

Country Link
WO (1) WO2025120155A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5738834A (en) * 1980-08-18 1982-03-03 Shimada Kankyo Kagaku Kenkyusho:Kk Treatment for reclaiming waste polyvinyl chloride
WO2006053907A1 (fr) 2004-11-22 2006-05-26 Solvay (Société Anonyme) Procede de purification de polymeres du chlorure de vinyle (pvc) par elimination des metaux lourds
WO2006069856A1 (fr) 2004-11-22 2006-07-06 Solvay (Société Anonyme) Procede de purification de polychlorures de vinyle (pvc) pour enlever les metaux lourds
WO2009037316A1 (fr) 2007-09-21 2009-03-26 Solvay (Societe Anonyme) Processus pour extraire un polymère à partir d'une solution
WO2022240253A1 (fr) * 2021-05-14 2022-11-17 (주)엘엑스하우시스 Matériau en poly(chlorure de vinyle) recyclé

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5738834A (en) * 1980-08-18 1982-03-03 Shimada Kankyo Kagaku Kenkyusho:Kk Treatment for reclaiming waste polyvinyl chloride
WO2006053907A1 (fr) 2004-11-22 2006-05-26 Solvay (Société Anonyme) Procede de purification de polymeres du chlorure de vinyle (pvc) par elimination des metaux lourds
WO2006069856A1 (fr) 2004-11-22 2006-07-06 Solvay (Société Anonyme) Procede de purification de polychlorures de vinyle (pvc) pour enlever les metaux lourds
WO2009037316A1 (fr) 2007-09-21 2009-03-26 Solvay (Societe Anonyme) Processus pour extraire un polymère à partir d'une solution
WO2022240253A1 (fr) * 2021-05-14 2022-11-17 (주)엘엑스하우시스 Matériau en poly(chlorure de vinyle) recyclé

Similar Documents

Publication Publication Date Title
JP5231703B2 (ja) プラスチックのリサイクル方法
CA2895486C (fr) Procede d'extraction d'elements d'impurete du magnesium d'une solution renfermant du nickel
KR101596529B1 (ko) 폴리페닐렌술피드 수지 미립자의 제조 방법, 폴리페닐렌술피드 수지 미립자 및 그의 분산액
AU2016344326B2 (en) Composite extractant-enhanced polymer resin, method of making the same, and its usage for extraction of valuable metal(s)
US7759458B2 (en) Process for the purification of vinyl chloride polymers (PVC) from heavy metals
CA2295066C (fr) Precipitation selective de nickel et de cobalt
AU2024201376B2 (en) Method for producing aqueous solution containing nickel or cobalt
JP5425785B2 (ja) 溶液からポリマーを回収する方法
EP4182050A1 (fr) Procédé d'élimination des contaminants d'un thermoplastique contaminé
CN101061164B (zh) 用于净化氯乙烯聚合物（pvc）中的重金属的方法
WO2025120155A1 (fr) Procédé de production d'un polymère de polychlorure de vinyle (pvc)
RU2650147C2 (ru) Способ обработки отработанного твердого ракетного топлива
JP5828920B2 (ja) ジルコニウム塩化物水溶液の製造方法
WO2025120154A1 (fr) Procédé de purification de pvc
KR101966063B1 (ko) 제강분진, 망간폐기물 및 구리폐기물로부터 황산아연, 황산철, 황산구리 및 황산망간을 포함하는 복합 미네랄을 제조하는 방법
JPH11192469A (ja) プラスチックの処理方法および該処理方法で得られる固体燃料、鉱石用還元剤
JP2021161449A (ja) Ｓｃの抽出方法
EP4378554A1 (fr) Procédé de recyclage de matières plastiques post-consommation
JP2024522596A (ja) ポリカーボネートに基づく複合廃棄物のリサイクル及びアップサイクル方法
WO2025186410A1 (fr) Procédé
JP2010144131A (ja) プラスチックの分解方法
RU2084550C1 (ru) Способ получения тантала и ниобия из их соединений
JP2002179833A (ja) 回収難燃剤成分の分離方法
JP2003261709A (ja) ジクロロメタンを用いた塩化ビニル重合体の回収方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24820744

Country of ref document: EP

Kind code of ref document: A1