Method for recycling contaminated polymers

Abstract

The present invention relates to an improved method for depolymerization of contaminated polymers, such as PMMA, which involves separation of the contaminants from the resulting monomer by using an appropriate agent to trap the contaminants.

Claims

1. 1. A method for recycling plastics comprising one or more polymers contaminated with contaminants, wherein at least one contaminant is other than PET, PVC, or decomposition products thereof, the method comprising: contacting at least one solid trapping agent with the contaminated polymer to be depolymerized; depolymerizing the polymer to yield the corresponding monomers, whereby the non-PET and non-PVC contaminants interact with the solid trapping agent; at least partially continuously extracting the non-PET and non-PVC contaminants bound to the solid trapping agent from the reaction mixture; A method comprising:

2. 2. The method of claim 1, wherein the PET decomposition products and PVC decomposition products include terephthalic acid, dimethyl terephthalate, hydrochloric acid, and benzoic acid.

3. 3. The method of claim 1 or 2, wherein the polymer is selected from the group consisting of polyhydroxyalkanoates (PHAs) including poly(methyl methacrylate) (PMMA), polystyrene (PS), poly-3-hydroxybutyrate, poly-3-hydroxy-butyrate-4-hydroxy-butyrate, poly-3-hydroxypropionate, polyhydroxybutyrate-valerate, and polyhydroxyisobutyrate.

4. 4. The process according to any one of claims 1 to 3, wherein the resulting monomer is selected from the group consisting of methyl methacrylate (MMA), styrene and crotonic acid, butyrolactone, acrylic acid, and 2-pentenoic acid.

5. 5. The method of claim 1, wherein the contaminated polymer is PMMA.

6. 6. The method according to claim 1, wherein the monomer is methyl methacrylate (MMA).

7. 7. The method of any one of claims 1 to 6, wherein the non-PET and non-PVC contaminants are selected from the group consisting of metals, metal oxides, metal chlorides, metal hydroxides, hydrocarbons, halogenated hydrocarbons, alkalis; polymers (e.g., EVA, polyethylene, rubber, polyurethane, polysiloxane), adhesives; pigments and colorants, e.g., cadmium-based pigments, chromium-based pigments, lead-based pigments, selenium-based pigments; crosslinking agents, e.g., comonomers; methacrylic acid and acetic acid; plasticizers, fillers, lubricants, biocides, catalysts and radical initiators, light stabilizers, heat stabilizers, chain transfer agents, antioxidants, flame retardants, odorants, antistatic agents, impact modifiers, blowing agents, odorants.

8. Non-PET contaminants and non-PVC contaminants are listed below with CAS numbers: 12769-96-9; 1317-65-3; 1345-16-0; 51274-00-1; 65997-17-3; 68186-85-6; 68186-88-9; 68186-90-3; 68186-91-4; 68186-94-7; 68187-11-1; 68187-51-9; 68412-38-4; 71631-15-7; 8007-18-9; 58339-34-7; 68187-49-5; 8048-07-5; 68186-97-0; 61951-89-1; 12236 -03-2;164251-88-1;68186-87-8;68187-15-5;68187-54-2;80748-21-6;68186-92-5;54824-37-2;7664-93-9;7440-43-9;1306-19-0;7778-50-9; 10588-01-9;1308-38-9;7789-12-0;1314-41-6;1317-36-8;7439-92-1;13424-46-9;7758-97-6;7439-97-6;1309-64-4;12737-27-8;12767-90-7;1 309-37-1;1314-13-2;1317-61-9;13463-67-7;14059-33-7;12062-81-6;1317-80-2;18282-10-5;1306-24-7;1314-35-8;3251-23-8;7779-88-6;1 0108-64-2;7790-79-6;7790-80-9;7758-95-4;7487-94-7;7546-30-7;10112-91-1;7786-30-3;7646-78-8;7646-85-7;7550-45-0;7772-99-8;1692 3-95-8;16919-27-0;13826-88-5;1306-23-6;7446-14-2;12656-85-8;1344-37-2;1344-48-5;7783-35-9;1314-98-3;7727-21-1;7727-43-7;7631- 90-5;10124-36-4;7446-27-7;12141-20-7;13453-65-1;16038-76-9;24824-71-3;53807-64-0;10101-66-3;265647-11-8;12167-74-7;7631-86-9;7440-21-3;102184-95-2;17010-21-8;25808-74-6;1333-86-4;81-77-6;89-65-6;143-29-3;198-55-0;2475-46-9;16294-75-0;545-55-1;542-83-6;1319-46-6;628-86-4;1335-31-5;471-34-1;546-93-0;14455-29-9;25869-00-5;1328-53-6;14302-13-7;50-00-0;2832-40-8;842-07-9;3846-71-7;25973-55-1;36437-37-3;149-57-5;85-68-7;117-81-7;84-74-2;53306-54-0;84-66-2;605-50-5;84-75-3;77-90-7;120-55-8;33703-08-1;27138-31-4;68-12-2;50-32-8;56-55-3;120-12-7;192-97-2;193-39-5;205-82-3;205-99-2;207-08-9;218-01-9;84-61-7;26761-40-0;10081-67-1;103-23-1;109-31-9;128-37-0;131-56-6;131-57-7;1709-70-2;1843-05-6;2082-79-3;23128-74-7;2440-22-4;28553-12-0;3147-75-9;32687-78-8;36443-68-2;52829-07-9;57-11-4;57-13-6;65-85-0;6683-19-8;70321-86-7;77-89-4;77-93-0;77-94-1;82469-79-2;88-24-4;41556-26-7;82919-37-7;103597-45-1;1047-16-1;106990-43-6;107-22-2;108-78-1;108-88-3;110-27-0;110-33-8;111-46-6;115-77-5;1189-08-8;127-19-5;141-17-3;142-90-5;3290-92-4;4118-16-5;4702-90-3;4948-15-6;5521-31-3;614-45-9;67-64-1;68516-73-4;6925-69-5;71-43-2;74-85-1;79-10-7;80-43-3;80-62-6;81-33-4;81-48-1;868-77-9;94-28-0;97-90-5;980-26-7;102-71-6;105-64-6;109-16-0;111-42-2;111-96-6;115-11-7;124172-53-8;128-80-3;140-88-5;147315-50-2;150-76-5;1533-45-5;23949-66-8;2725-22-6;3049-71-6;32724-62-2;5232-99-5;6197-30-4;6829-22-7;72102-84-2;732-26-3;7397-62-8;78-67-1;82-38-2;88-12-0;924-42-5;97-88-1;99-97-8;124-07-2;334-48-5;2475-45-8;119-90-4;84-65-1;3333-62-8;719-22-2;2764-13-8;4051-63-2;106-10-5;88-26-6;514-10-3;32360-05-7;109-17-1;3077-12-1;85-69-8;141-18-4;10373-78-1;3333-52-6;22041-23-2;22759-34-8;1565-94-2;106-74-1;24817-92-3;1113-92-4;10024-58-5;136-84-5;63843-89-0;23328-53-2;6505-29-9;28198-05-2;81-39-0;91-44-1;5089-22-5;40470-68-6;2512-29-0;574-93-6;5395-50-6;7576-65-0;1017-56-7;6300-37-4;6250-23-3;140-95-4;3370-35-2;3068-00-6;85136-74-9;3179-90-6、56524-77-7;116-85-8;4991-32-6;3179-89-3;2872-52-8;7327-69-7;6358-83-4;3720-97-6;119-15-3;730-40-5;2581-69-3;3883-23-6;12236-29-2;4913-31-9;1854-26-8;134-97-4;3270-74-4;6373-73-5;6531-31-3;13747-12-1;3380-34-5;32534-81-9;1163-19-5;25637-99-4;101-14-4;3864-99-1;3896-11-5;12236-62-3;15793-73-4;20749-68-2;3089-17-6;5280-68-2;5280-78-4;6358-85-6;84632-65-5;30125-47-4;3905-19-9;5280-80-8;5580-57-4;56-37-1;61847-48-1;79953-85-8;591-50-4;6041-94-7;32432-45-4;23739-66-4;68399-99-5;632-58-6;569-61-9;5421-66-9;68391-30-0;4261-72-7;6359-50-8;6359-45-1;6320-14-5;3207-12-3;13301-61-6;2787-91-9;2465-27-2;6364-35-8;65907-69-9;13810-83-8;123-28-4;29598-76-3;41484-35-9;693-36-7;7128-64-5;3622-84-2;35325-02-1;1212-08-4;22796-14-1;13676-91-0;72968-71-9;12671-74-8;522-75-8;68516-81-4;15141-18-1;1241-94-7;26741-53-7;29761-21-5;31570-04-4;78-51-3;38613-77-3;5945-33-5;78-33-1;115-88-8;7580-37-2;52221-67-7;512-82-3;22031-17-0;115-96-8;13674-87-8;126-72-7;124-64-1;26248-87-3;55566-30-8;56-35-9;4464-23-7;75-74-1;78-00-2;301-04-2;1072-35-1;1335-32-6;6838-85-3;7428-48-0;15245-44-0;16183-12-3;55-68-5;100-57-2;593-74-8;627-44-1;62-38-4;103-27-5;13302-00-6;13864-38-5;26545-49-3;147-14-8;603-36-1;142-71-2;28654-73-1;139-12-8;7360-53-4;123-88-6;17570-76-2;5281-04-9;24887-06-7;6035-47-8;65212-77-3;2530-83-8;1760-24-3;2530-85-0;65996-93-2;90640-86-1;67701-03-5;63148-62-9;70131-50-9;91052-47-0;68909-79-5;4464-46-1;1373399-58-6;101357-30-6; 8002-74-2;71888-89-6;90640-80-5;90640-81-6;90640-82-7;91995-15-2;91995-17-4;68515-50-4;68515-49-1;65447-77-0;68411-46-1;125643-61-0;104810-48-2;125304-04-3;129757-67-1;25852-37-3;71878-19-8;9003-08-1;9003-20-7;9011-05-6;9011-14-7;2600 7-43-2;70198-29-7;68515-51-5;736150-63-3;72245-46-6;9011-13-6;9003-63-8;9003-42-3;9011-15-8;25087-17-6;25609-74-9;26655-94-7;29356-88-5;25768-50-7;25087-18-7;25719-51-1;29320-53-4;25719-52-2;25986-80-5;25639-21-8;64114-51-8;25189-01-9 8. The method of claim 1, wherein the compound is selected from the group consisting of compounds represented by the formula: CAS 79-41-4; CAS 64-19-7 and CAS 81457-65-0.

9. The trapping agent is Dolomite, Diatomaceous earth, Magnesium oxide, aluminum oxide, strontium oxide, barium oxide, lanthanum oxide, magnesium hydroxide, aluminum hydroxide, strontium hydroxide, barium hydroxide, lanthanum hydroxide, magnesium sulfate, aluminum sulfate, strontium sulfate, barium sulfate, lanthanum sulfate, and magnesium carbonate, aluminum carbonate, strontium carbonate, barium carbonate, lanthanum carbonate, in particular, magnesium oxide, aluminum oxide, strontium oxide, barium oxide, lanthanum oxide, and magnesium carbonate, aluminum carbonate, strontium carbonate, barium carbonate, lanthanum carbonate, Metal oxides, such as zinc oxide and iron oxide; Supported organic peroxides and supported inorganic peroxides; Glass fiber, Aluminum trihydroxide (used in solid surface materials in combination with PMMA), as well as aluminum oxide and hydrated aluminum oxide; Silica-alumina, titanium dioxide and combinations of these materials 9. The method according to claim 1 , wherein the compound is selected from the group consisting of

10. 10. The method according to any one of claims 1 to 9, wherein the trapping agent is selected from dolomite, diatomeaceous earth, magnesium oxide, hydroxide or carbonate, aluminium oxide or trihydrate, calcium oxide, hydroxide or carbonate, titanium dioxide and silica-alumina.

11. 11. The method according to any one of claims 1 to 10, wherein the combination of the trapping agent and the non-PET and non-PVC contaminants is selected from Table 1 of the present application.

12. The trapping agent is 12. The method according to any one of claims 1 to 11, wherein the plastic to be recycled is added as a separate component or as an additive to a secondary plastic which is added to the plastic to be recycled.

13. Supported organic peroxides include supported, Luperox 120XL45, Luperox 101XL45, Luperox HP101XLP, Luperox 101PP20 (less preferred), Luperox F40KE, F40KEP, Luperox DC40P, DC40KE, DC40KEP, Luperox 231XL40, 230XL 40, NOROX® DCP-40CC, NOROX® DCP-40BKC, ​​DHBP-45-IC2, Trigonox 101-50D-PD, Trigonox 101-45B-GR, Trigonox 101-45D-PD, Perkadox 14-40B-PD / GR-S, Perkadox 14-40MB-GR-S, Perkadox 8. The method of claim 7, wherein the active ingredient is selected from the group consisting of Perkadox BC-40B-PD / GR, Perkadox BC-40K-PD, Perkadox BC-40MB-GR, Perkadox BC-EP40, Triganox 17-40B-PD / GR, Triganox 17-40MB-GR, Triganox 29-40B-PD / GR-E, Triganox 29-40MB-GR-E.

14. 10. The method of claim 7 or 9, wherein the supported organic peroxide is in the form of granules or pellets.

15. 10. The method according to claim 7 or 9, wherein the supported organic peroxide comprises at least 15% by weight of solid support, preferably between 20% and 70% by weight.

16. 10. The method of claim 7 or 9, wherein the solid support comprises an inorganic compound or a polymer.

17. 17. The method of any one of claims 1 to 16, wherein the non-PET and non-PVC contaminants that bind to the solid trapping agent are collected in the form of dust, char, wax, mist, or oligomers.

18. 18. The method according to any one of claims 1 to 17, wherein the depolymerization step is carried out by pyrolyzing the plastic in a pyrolysis reactor to produce a stream containing monomers and contaminants.

19. The extracting step comprises: removing said contaminants from the stream in a separator downstream of the reactor; directing the monomer gas stream from the separator to a condenser to condense the monomer contained in the stream; Including, In the separator, the temperature of the stream is strictly maintained above the boiling point of the monomer; 19. The method according to any one of claims 1 to 18.

20. 20. The process of claim 18, wherein the pyrolysis reactor is a twin screw extruder or an auger screw reactor.

21. 21. The method of claim 19 or 20, wherein the separator comprises a separation chamber and an inlet duct for receiving and directing the stream produced by the pyrolysis reactor to the separation chamber, the stream being collected in the separation chamber.

22. 22. The method according to any one of claims 19 to 21, wherein the flow gradually slows down inside the separator along the inlet duct.

Images