# US 11,028,248 B2 · System and process for recycling contaminated polyolefins > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,028,248 B2 - Document ID: US11028248B2 - Status: Granted - Kind: B2 - Application number: 16/462,170 - Filed: 2017-11-09 - Published: 2019-10-31 - Granted: 2021-06-08 - Earliest claimed: 2016-11-17 - Assignees: Alpla Werke Alwin Lehner GmbH & Co. KG - Applicants: Alpla Werke Alwin Lehner GmbH & Co. KG - Inventors: Robert Siegl; Andreas Weber - Web page: https://patentgrep.com/patent/US11028248B2 ## CPC - A61C 5/007: {Dental splints; teeth or jaw immobilisation devices; stabilizing retainers bonded to teeth after orthodontic treatments} - C08J 11/08: using selective solvents for polymer components - A61C 7/002: {Orthodontic computer assisted systems} - B01D 11/0257: {using mixing mechanisms, e.g. stirrers, jets (B01D11/0242 takes precedence)} - B01D 11/028: {Flow sheets} - B29B 17/02: Separating plastics from other materials - A61C 13/0022: {Blanks or green, unfinished dental restoration parts} - A61L 2/00: Disinfection or sterilisation of materials or objects, in general; Accessories therefor - A61L 11/00: Methods specially adapted for refuse {(disintegrating medical waste B02C19/0075; disposal of medical waste B09B3/00)} - B01D 11/0288: {Applications, solvents} - B29B 2017/0293: {Dissolving the materials in gases or liquids} - B29C 48/762: {Vapour stripping} - B29K 2023/00: Use of polyalkenes {or derivatives thereof} as moulding material - B29K 2023/065: {HDPE, i.e. high density polyethylene} - B29K 2105/26: Scrap {or recycled material} - C08J 2323/06: Polyethene - C08J 2323/12: Polypropene - Y02W 30/62: Plastics recycling; Rubber recycling - A61C: DENTISTRY; APPARATUS OR METHODS FOR ORAL OR DENTAL HYGIENE (non-driven toothbrushes A46B; {tongue scrapers A61B17/24;} preparations for dentistry A61K6/00; preparations for cleaning the teeth or mouth A61K8/00, A61Q11/00) - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS - A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K) - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS - Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT ## 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 ### Claim 1 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, whereby 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. ### Claim 2 (depends on 1) The method of claim 1, wherein the polyolefin material consists essentially of polyethylene or polypropylene. ### Claim 3 (depends on 1) The method of claim 1, further comprising drying the polyolefin in a drier after pressing the swollen polyolefin to vaporize solvent remaining in the polyolefin material. ### Claim 4 (depends on 1) The method of one of claim 1, 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. ### Claim 5 (depends on 4) The method of claim 4, further comprising using an extruder having a degasification zone to extrude the polyolefin. ### Claim 6 (depends on 4) The method of claim 4, further comprising heating the polyolefin granulate in a solid-state condensation reactor or in a vacuum. ### Claim 7 (depends on 1) The method of one claim 1, 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. ### Claim 8 (depends on 1) The method of claim 1, 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. ### Claim 9 (depends on 1) The method of claim 1, 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. ### Claim 10 (depends on 1) The method of claim 1, wherein the solvent has a lower polarity than water. ### Claim 11 (depends on 1) The method of claim 1, wherein the solvent is an alkane comprising n-hexane or n-heptane. ### Claim 12 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 comprising a system to compress swollen polyolefin material placed downstream of the swelling reactor to remove the solvent and the contaminants dissolved in the solvent from the polyolefin material and to compress the swollen polyolefin material. ### Claim 13 (depends on 12) The recycling system of claim 12, wherein the recycling system comprises an upgraded or converted PET recycling system. ### Claim 14 (depends on 12) The recycling system of claim 12, 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. ### Claim 15 (depends on 12) The recycling system of claim 12, wherein the system component placed downstream of the swelling reactor to remove the solvent from the polyolefin material further comprises a drier. ### Claim 16 (depends on 12) The recycling system of claim 12, wherein the swelling reactor comprises a stirring vessel, a stirring vessel cascade or a tube reactor. ### Claim 17 (depends on 12) The recycling system of claim 12, further comprising a granulator downstream of the swelling reactor for melting, extruding and granulating the polyolefin material. ### Claim 18 (depends on 12) The recycling system of claim 12, further comprising a purification system downstream of the swelling reactor to purify the solvent. ### Claim 19 (depends on 18) The recycling system of claim 18, wherein the purification system comprises a means of distillation or rectification and a means to recycle the purified solvent back into the swelling reactor. ### Claim 20 (depends on 12) The recycling system of claim 12, 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. ### Claim 21 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, whereby removing the contaminants in the solvent from the polyolefin material includes compressing the swollen polyolefin material, through which a majority of the solvent is pressed out of the swollen polyolefin material. ### Claim 22 (depends on 21) The purified polyolefin material of claim 21, 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 comprising a system to compress swollen polyolefin material to compress the swollen polyolefin material 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.