SYSTEM AND PROCESS FOR RECYCLING CONTAMINATED POLYOLEFINS

• US 20190330439A1
• Filed: 11/09/2017
• Published: 10/31/2019
• Est. Priority Date: 11/17/2016
• Status: Active Grant

• Current Assignee: Alpla Werke Alwin Lehner GmbH & Company KG (Alpla Privatstiftung)
• Original Assignee: Alpla Werke Alwin Lehner GmbH & Company KG (Alpla Privatstiftung)
• Inventors: Siegl, Robert, Weber, Andreas
• Granted Patent: US 11,028,248 B2
• Time in Patent Office: Days
• CPC Class Codes: A61C 13/0022 Blanks or green, unfinished dental restoration parts
• CPC Class Codes: A61C 5/007 Dental splints; teeth or jaw immobilisation devices; stabilizing retainers bonded to teeth after orthodontic treatments
• CPC Class Codes: A61C 7/002 Orthodontic computer assisted systems
• CPC Class Codes: A61L 11/00 Methods specially adapted for refuse disintegrating medical waste B02C19/0075; disposal of medical waste B09B3/00
• CPC Class Codes: A61L 2/00 Methods or apparatus for disinfecting or sterilising materials or objects other than foodstuffs or contact lenses; Accessories therefor for contact lenses A61L12/00; atomisers for disinfecting agents A61M; sterilisation of packages or package contents in association with packaging B65B55/00; treatment of water, waste water, sewage or sludge C02F; disinfecting paper D21H21/36; disinfecting devices for water closets E03D; articles having provision for disinfection, see the relevant subclasses for these articles, e.g. H04R1/12
• CPC Class Codes: B01D 11/0257 using mixing mechanisms, e.g. stirrers, jets B01D11/0242 takes precedence
• CPC Class Codes: B01D 11/028 Flow sheets
• CPC Class Codes: B01D 11/0288 Applications, solvents
• CPC Class Codes: B29B 17/02 Separating plastics from other materials
• CPC Class Codes: B29B 2017/0293 Dissolving the materials in gases or liquids
• CPC Class Codes: B29K 2023/00 Use of polyalkenes or derivatives thereof as moulding material
• CPC Class Codes: B29K 2023/065 HDPE, i.e. high density polyethylene
• CPC Class Codes: B29K 2105/26 Scrap or recycled material
• CPC Class Codes: C08J 11/08 using selective solvents for polymer components
• CPC Class Codes: C08J 2323/06 Polyethene
• CPC Class Codes: C08J 2323/12 Polypropene
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling

Abstract

The invention relates to a recycling process for contaminated polyolefins, in particular HDPE, wherein the contaminated polyolefin is swelled using a solvent such that contaminants in the polyolefin dissolve in the solvent, and the solvent as well as the contaminants dissolved from the solvent are removed from the polyolefin.

Claims

1-17. -17. (canceled)

18. A method of recycling contaminated polyolefins, including removal of contaminants from a contaminated polyolefin material, comprising:

swelling a contaminated polyolefin material with a solvent causing contaminants in the polyolefin material to dissolve in the solvent; and

removing the solvent and the contaminants in the solvent from the polyolefin material.

19. The method of claim 18, wherein the polyolefin material consists essentially of polyethylene or polypropylene.

20. The method of claim 18, wherein removing the contaminants dissolved in the solvent from the polyolefin material includes a compression of the swollen polyolefin material, through which a majority of the solvent is pressed out of the swollen polyolefin material.

21. The method of claim 20, further comprising drying the polyolefin in a drier after pressing the swollen polyolefin to vaporize solvent remaining in the polyolefin material.

22. The method of one of claim 18, further comprising melting and extruding the polyolefin material to remove residual solvent from the polyolefin material, the polyolefin material then being granulated to form a polyolefin granulate.

23. The method of claim 22, further comprising using an extruder having a degasification zone to extrude the polyolefin.

24. The method of claim 22, further comprising heating the polyolefin granulate in a solid-state condensation reactor or in a vacuum.

25. The method of one claim 18, further comprising comminuting the contaminated polyolefin material to flakes and foreign material and separating the foreign materials from the contaminated polyolefin material by one or more sorting methods comprising a dry sorting method or at least one washing step in water.

26. The method of claim 18, wherein the swelling the contaminated polyolefin material is at a temperature of about 10°

C. below a melting temperature of the polyolefin material, and at a pressure between 1 and 1000 bar, for at least 5 minutes, and moving the polyolefin in the solvent during the swelling.

27. The method of claim 18, wherein the swelling the contaminated polyolefin material causes a volume of the contaminated polyolefin material to increase through the swelling by at least 1 percent.

28. The method of claim 18, wherein the solvent has a lower polarity than water.

30. A recycling system for recycling contaminated polyolefins, comprising:

a swelling reactor containing a solvent, the solvent having a lower polarity than water, with the swelling reactor configured to swell a contaminated polyolefin material in the presence of the solvent and to dissolve contaminants present in the polyolefin material in the solvent; and

a system component placed downstream of the swelling reactor to remove the solvent and the contaminants dissolved in the solvent from the polyolefin material.

29. The method of claim 30, wherein the solvent is an alkane comprising n-hexane or n-heptane.

31. The recycling system of claim 30, wherein the recycling system comprises an upgraded or converted PET recycling system.

32. The recycling system of claim 30, further comprising separation and washing stages placed upstream of the swelling reactor for separating out foreign materials from the polyolefin material and a drier placed downstream of the swelling reactor.

33. The recycling system of claim 30, wherein the system component placed downstream of the swelling reactor to remove the solvent from the polyolefin material comprises a system to compress the swollen polyolefin material or a drier.

34. The recycling system of claim 30, wherein the swelling reactor comprises a stirring vessel, a stirring vessel cascade or a tube reactor.

35. The recycling system of claim 30, further comprising a granulator downstream of the swelling reactor for melting, extruding and granulating the polyolefin material.

36. The recycling system of claim 30, further comprising a purification system downstream of the swelling reactor to purify the solvent.

37. The recycling system of claim 36, wherein the purification system comprises a means of distillation or rectification and a means to recycle the purified solvent back into the swelling reactor.

38. The recycling system of claim 30, wherein the swelling reactor is configured to swell the contaminated polyolefin material with the solvent at at least one of a temperature of about 10°

C. below a melting temperature of particular polyolefin material or a pressure between 1 and 1000 bar.

39. A purified polyolefin material manufactured by a method of recycling contaminated polyolefins, including removal of contaminants from a contaminated polyolefin material, the method comprising:

swelling a contaminated polyolefin material with a solvent causing contaminants in the polyolefin material to dissolve in the solvent; and

removing the solvent and the contaminants in the solvent from the polyolefin material to produce the purified polyolefin material.

40. The purified polyolefin material of claim 39, wherein the purified polyolefin material is manufactured by a method of recycling contaminated polyolefin using a recycling system for recycling contaminated polyolefins, the recycling system comprising:

a swelling reactor containing a solvent, the solvent having a lower polarity than water, with the swelling reactor configured to swell a contaminated polyolefin material in the presence of the solvent and to dissolve contaminants present in the polyolefin material in the solvent; and

a system component placed downstream of the swelling reactor to remove the solvent and the contaminants dissolved in the solvent from the polyolefin material producing the purified polyolefin material.