# US 11,305,309 B2 · Method and device for removing coating on coated plastic article > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,305,309 B2 - Document ID: US11305309B2 - Status: Granted - Kind: B2 - Application number: 16/849,522 - Filed: 2020-04-15 - Published: 2020-07-30 - Granted: 2022-04-19 - Earliest claimed: 2017-10-20 - Assignees: Yamaguchi Prefectural Industrial Technology Institute; ODA SANGYOU Co., Ltd. - Applicants: Yamaguchi Prefectural Industrial Technology Institute; ODA SANGYOU Co., Ltd. - Inventors: Fumiaki Tomonaga; Syougo Miyazaki; Shigemasa Oda - Web page: https://patentgrep.com/patent/US11305309B2 ## CPC - B05C 3/04: with special provision for agitating the work or the liquid or other fluent material - C09D 9/00: Chemical paint or ink removers (fluid media for correction of typographical errors by coating C09D10/00) - B05D 3/10: by other chemical means - B05D 2201/02: Polymeric substrate - B29B 2017/001: {Pretreating the materials before recovery} - B29B 2017/0015: {Washing, rinsing} - B05C: APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (spraying apparatus, atomising apparatus, nozzles B05B; plant for applying liquids or other fluent materials to objects by electrostatic spraying B05B5/08) - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) - B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02) - 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 ## Abstract A method and a device for removing a coating on a coated plastic article allow highly efficient removal of a coating from a coated plastic article and recovery of a base after coating removal and a remover. A method for removing a coating on a coated plastic article with a remover includes shredding the article into pieces, immersing the pieces in the remover heated to a second temperature, heating the remover to a first temperature, and stirring the pieces with the heated remover. The remover includes at least one monohydric lower alcohol selected from methanol, ethanol, propanol, and 1-butanol, and swells the base, the coating, or both. The first temperature is not lower than 25° C. and not higher than a temperature 10° C. lower than a boiling point of the remover. The second temperature is not higher than an upper limit of the first temperature. ## Claims ### Claim 1 A method for removing a coating on a coated plastic article with a remover, the coating containing a synthetic resin component and being on a surface of a plastic base included in the coated plastic article, the method comprising: shredding the coated plastic article into a plurality of pieces; heating the remover to a first temperature; and stirring the plurality of pieces with the heated remover, wherein the remover includes at least one monohydric lower alcohol selected from the group consisting of methanol, ethanol, propanol, and 1-butanol, and swells at least one of the base or the coating, the base is free from polycarbonate and contains polyolefin as a main component, the remover is 1-butanol, the first temperature is not lower than 70° C. and not higher than a temperature that is 10° C. lower than the boiling point of the remover, the method further comprises, before the stirring, immersing the plurality of pieces in the remover heated to a second temperature, and the second temperature is not higher than an upper limit temperature of the first temperature. ### Claim 2 (depends on 1) The method according to claim 1, wherein the base is free from polycarbonate, polyester, and polyurethane, and the remover contains a sodium hydroxide solution and a sodium hydroxide concentration in the remover is in a range of 0.01 to 0.5 wt %. ### Claim 3 (depends on 1) The method according to claim 1, wherein the plurality of pieces have a maximum size in a range of 10 to 100 mm. ### Claim 4 A method for removing a coating on a coated plastic article with a remover, the coating containing a synthetic resin component and being on a surface of a plastic base included in the coated plastic article, the method comprising: shredding the coated plastic article into a plurality of pieces; heating the remover to a first temperature; and stirring the plurality of pieces with the heated remover, wherein the remover includes at least one monohydric lower alcohol selected from the group consisting of methanol, ethanol, propanol, and 1-butanol, and swells at least one of the base or the coating, the base contains acrylonitrile butadiene styrene resin or acrylonitrile styrene acrylate resin, the remover includes one selected from the group consisting of methanol, ethanol, and a mixture of methanol and ethanol, the first temperature is not lower than 25° C. and not higher than 55° C., the method further comprises, before the stirring, immersing the plurality of pieces in the remover heated to a second temperature, and the second temperature is not higher than an upper limit temperature of the first temperature. ### Claim 5 (depends on 4) The method according to claim 4, wherein the base is free from polycarbonate, polyester, and polyurethane, and the remover contains a sodium hydroxide solution and a sodium hydroxide concentration in the remover is in a range of 0.01 to 0.5 wt %. ### Claim 6 (depends on 4) The method according to claim 4, wherein the plurality of pieces have a maximum size in a range of 10 to 100 mm.