Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • 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
  • C09D9/00—Chemical paint or ink removers
  • C09D9/04—Chemical paint or ink removers with surface-active agents
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • 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
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/02—Separating plastics from other materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • 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
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/04—Disintegrating plastics, e.g. by milling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • 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
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/02—Separating plastics from other materials
  • B29B2017/0203—Separating plastics from plastics
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • 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
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/02—Separating plastics from other materials
  • B29B2017/0213—Specific separating techniques
  • B29B2017/0293—Dissolving the materials in gases or liquids
  • B29B2017/0296—Dissolving the materials in aqueous alkaline solutions, e.g. NaOH or KOH
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • 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
  • B29B17/00—Recovery of plastics or other constituents of waste material containing plastics
  • B29B17/04—Disintegrating plastics, e.g. by milling
  • B29B2017/0424—Specific disintegrating techniques; devices therefor
  • B29B2017/0468—Crushing, i.e. disintegrating into small particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2009/00—Layered products
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

• the present invention relates to an ink stripping method for stripping an ink layer from a plastic substrate provided with an ink layer, an ink stripping agent used in the stripping method, and a plastic recovery method using these.
• Non-Patent Document 1 Recycled plastic products are difficult to return to the same product from the viewpoint of cost, and basically deteriorate each time they are recycled, so they have no choice but to be reborn as products of lower quality.
• One of the reasons why the quality of recycled plastics deteriorates is that inks and pigments are mixed in with the plastics as impurities.
• many plastic products are printed on their surfaces, making it difficult to decolorize them during the recycling process, resulting in colored recycled plastic products.
• Recycled plastics that contain such pigments and inks not only have a significantly low commercial value due to their coloring, but also become plastics with physical properties degraded due to impurities. There is a strong demand for recycling methods that produce recycled plastics.
• Patent Document 1 provides an ink mainly composed of a high acid value resin in order to remove the ink printed on plastic products in an alkaline solution. No significant printability degradation is noted.
• Patent Document 2 provides a method of stirring in a heated alkaline solution as a method for peeling a printed layer from a plastic product. A release layer is required.
• high acid value resins such as fumaric acid, phthalic acid, and maleic acid are used for the ink and/or the release layer.
• a large amount of alkaline solution is required because the alkaline solution is neutralized.
• Patent Document 3 uses a 5% sodium hydroxide aqueous solution as an alkaline detergent capable of washing steel plates, and polyoxyethylene alkyl ether as an additive. Further, Patent Documents 4 to 7 use a cleaning liquid composed of an amine compound, water, and glycol ether for each purpose. However, even with these exemplified cleaning agents, the ink layer printed on the film, which is the object of the present application, could not be peeled off.
• ink can be broadly divided into thermoplastic type ink and thermosetting type ink according to the type of resin used.
• Thermosetting type ink has a strong bond with the ink film and adheres to the plastic substrate. Therefore, it becomes more difficult to remove the ink film.
• laminated films in which the printed layer is provided between multiple films (reverse printing) it is necessary to separate the multiple films to remove the printed layer, so it is more difficult to peel off the ink film. becomes.
• the problem to be solved by the present invention is an ink stripping method that can easily strip an ink layer printed on a plastic substrate, an ink stripping agent that can be used in the stripping method, and these It relates to a method for recovering plastic substrates using
• the present invention uses an ink remover containing (a) 20% by mass or more of a water-soluble solvent and (b) 0.1% by mass to 10% by mass of an inorganic base, and a plastic substrate having an ink layer.
• an ink stripping method characterized by having a step of stripping and removing an ink layer from a substrate.
• the present invention also provides an ink remover for use in the ink removing method described above, comprising (a) 20% by mass or more of a water-soluble solvent and (b) 0.1% to 10% by mass of an inorganic base. provides an ink remover containing
• the present invention also provides a method for recovering a plastic substrate, which comprises recovering a plastic substrate from which the ink layer has been removed by the ink removing method described above.
• the ink layer can be easily peeled off from the plastic substrate provided with the ink layer. Therefore, it is possible to easily recover the plastic base material to which ink is not attached, and to improve the quality of the recycled plastic.
• the ink layer can be easily peeled off.
• the ink layer can be easily peeled off regardless of the type of plastic substrate, and the film can be separated into single layers, so that the ink layer recovery process can be facilitated.
• the ink remover used in the present invention can easily remove an ink layer from a plastic substrate having an ink layer, and contains (a) 20% by mass or more of a water-soluble solvent and (b) an inorganic base. 0.1% by mass to 10% by mass of water and, if necessary, a surfactant or the like.
• the plastic substrate from which the ink layer has been peeled off can be used for recovery, separation, and reuse, and since the ink has been removed, high-quality recycled plastic can be obtained.
• the water-soluble solvent preferably contains one or more water-soluble alcohols or water-soluble solvents having a flash point of 21°C or higher.
• the water-soluble solvent with a flash point of 21°C or higher is preferably a water-soluble solvent among the organic solvents that fall under the category of second petroleum and third category of petroleum under the Fire Defense Law.
• water-soluble alcohols alcohols specified in the Fire Defense Law can be mentioned. Specific examples of these include 3-methoxy-3-methyl-1-butanol, diethylene glycol monobutyl ether, ethanol and the like, and these may be used alone or in combination.
• the water-soluble solvent is preferably contained in the ink remover in the range of 20% by mass or more. If the content of the water-soluble solvent is less than 20% by mass, it becomes difficult to obtain a sufficient effect in removing the ink layer. From the viewpoint of the releasability of the ink layer, it is preferable that the release agent contains a large amount of water-soluble solvent. preferably 50% by mass or more, preferably 60% by mass or more, preferably 70% by mass or more, preferably 80% by mass or more, preferably 90% by mass or more, It is preferably at least 95% by mass.
• the release agent of the present invention contains (b) an inorganic base.
• the inorganic base include sodium hydroxide and potassium hydroxide, and potassium hydroxide is preferably used. These inorganic bases are contained at a concentration of 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on the total amount of the ink remover.
• the pH is preferably 10 or higher, preferably 11 or higher, and more preferably 12 or higher.
• the ink remover of the present invention may contain (c) water.
• water By containing water in the ink stripping agent, the working stability and environmental stability of the ink stripping method can be improved.
• the content of water is preferably 80% by mass or less with respect to the total amount of the ink remover. If the water content exceeds 80% by mass, it becomes difficult to obtain a sufficient effect in removing the ink layer.
• the ratio of the water-soluble solvent and water can be appropriately adjusted from the viewpoint of the ink layer peeling effect and safety, but the weight ratio of the water-soluble solvent: water should be in the range of 20:80 to 100:0. is preferred.
• the lower limit of the ratio of the water-soluble solvent in the total amount of the water-soluble solvent and water is preferably 20% by mass, preferably 30% by mass, preferably 40% by mass, and 50% by mass. is preferred, and 60% by mass is preferred.
• the ink remover of the present invention may contain (d) a surfactant.
• Surfactants are not particularly limited, and known surfactants can be used. Examples include anionic surfactants, nonionic surfactants, amphoteric surfactants, and cationic surfactants. .
• Nonionic surfactants generally include, for example, polyoxyalkylene alkyl ethers, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, Polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polyoxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, fatty acid alkylolamide, alkylalkanolamide, acetylene glycols, oxyethylene adducts of acetylene glycol, polyethylene glycol polypropylene glycol block copolymers, among others, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphen
• the ink remover contains 0.01% to 5% by weight of a polyoxyalkylene alkyl ether surfactant containing at least one compound represented by the general formula (1). preferable.
• R 1 represents a linear or branched alkyl group, alkenyl group or octylphenol group, n 1 represents the average number of added moles, and X 1 represents hydrogen or a short-chain alkyl group.
• a linear or branched alkyl group or alkenyl group having 10 or more carbon atoms represented by R 1 in general formula (1) is preferred.
• the specific number of carbon atoms is a decyl group with 10 carbon atoms, a lauryl group with 12 carbon atoms, a tridecyl group with 13 carbon atoms, a myristyl group with 14 carbon atoms, a cetyl group with 16 carbon atoms, and a carbon atom.
• Oleyl group and stearyl group of number 18 can be mentioned.
• Specific products include Noigen series, DSK NL-Dash series, and DKS-NL series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Nonion series manufactured by NOF Corporation, Emulgen series manufactured by Kao Corporation, and Leox manufactured by Lion Corporation.
• nonionic surfactants represented by the general formula (1) among the series, the Leocol series, the Lionol series, etc. if the number of carbon atoms represented by R 1 is 10 or more, it is applicable, but is limited to these. not a thing
• the HLB value of the polyoxyalkylene alkyl ether-based surfactant represented by the general formula (1) is not particularly limited.
• a specific surfactant having 10 or more carbon atoms represented by R 1 and an HLB value of less than 12.5 is Daiichi Kogyo
• R represents a linear or branched alkyl group or alkenyl group having 10 or more carbon atoms and an HLB value of 12.5 or more.
• R1 in general formula ( 1 ) is an octylphenol group
• octylphenol ethoxylate is preferred.
• Specific products include, but are not limited to, Dow Chemical Company's TRITON (registered trademark) series, Rhodia's Igepal CA series, Shell Chemicals' Nonidet P series, and Nikko Chemicals' Nikkol OP series. is not.
• amphoteric surfactant is preferably a betaine-type double-sided active agent, for example, an amphoteric interface of an alkylcarboxybetaine skeleton or an alkylamidocarboxybetaine skeleton containing at least one compound represented by the general formula (2a). It is more preferred to contain an active agent.
• R1 preferably represents a hydrogen atom.
• the compound represented by general formula (2a) is preferably an amphoteric surfactant having an alkylcarboxybetaine skeleton represented by general formula (2a-1).
• n represents the average number of added moles.
• n is preferably 8 or more, preferably 10 or more, and preferably 11 or more.
• Specific products corresponding to general formula (2a) include Nissan Anon BDF (registered trademark)-R, Nissan Anon BDF (registered trademark)-SF, Nissan Anon BDC-SF, and Nissan Anon BDL manufactured by NOF Corporation.
• -SF Amogen CB-H and Amogen HB-C manufactured by Daiichi Kogyo Seiyaku Co., Ltd.; Obazolin ISAB and the like.
• Amogen S, Amogen SH, and Amogen K manufactured by Daiichi Kogyo Seiyaku Co., Ltd. and Amphitol 20BS, Ambitol 24B, and Ambitol manufactured by Kao Corporation.
• Examples include, but are not limited to, ovazoline LB, ovazoline LB-SF, and the like.
• the betaine-type amphoteric surfactant may also have an imidazolinium betaine skeleton.
• Specific examples of such products include NISSAN ANON GLM-R and NISSAN ANON GLM-R-LV manufactured by NOF Corporation. , Amphithol 20Y-B manufactured by Kao Corporation, but not limited to these.
• amphoteric surfactant may be a surfactant represented by the following general formula (2b).
• R4-( NHC2H4 ) nb -N(R5)2 2b
• R4 represents a linear or branched alkyl group or alkenyl group
• nb represents an integer of 0 to 5
• R5 represents hydrogen, —CH 2 COONa, or —CH 2 COOH.
• two R5s present may be the same or different, and at least one R5 represents —CH 2 COONa.
• R4 preferably represents a linear alkyl group, and the number of carbon atoms in R4 is preferably 8 or more, preferably 10 or more, and preferably 12 or more.
• Specific products that fall under the general formula (2b) include Nissan Anon LG-R and Nissan Anon LA manufactured by NOF Corporation, but are not limited to these.
• amphoteric surfactant may also be an amine oxide type surfactant represented by the following general formula (2c).
• R6-N + (CH 3 ) 2 O - (2c) (In general formula (2c), R6 represents a linear or branched alkyl group or alkenyl group.) In general formula (2c), R6 preferably represents a linear alkyl group in general formula (2b), and the number of carbon atoms in R4 is preferably 8 or more, preferably 10 or more. , 12 or more.
• Specific products corresponding to general formula (2c) include Amogen AOL manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and Amphitol 20N manufactured by Kao Corporation, but are not limited to these.
• the cationic surfactant is preferably a cationic surfactant having a quaternary ammonium skeleton, for example, a cationic surfactant having a quaternary ammonium skeleton containing at least one compound represented by the general formula (3a). It is more preferred to contain an active agent.
• R1 is preferably a long-chain alkyl group or alkenyl group, specifically an al
• alkyl group having 10 to 25 carbon atoms is preferably an alkyl group having 10 to 25 carbon atoms, more preferably an alkyl group or alkenyl group having 12 to 22 carbon atoms.
• the alkyl group or alkenyl group may be linear or branched, preferably linear, more preferably linear alkyl.
• R2 and R3 preferably represent a straight-chain or branched-chain alkyl group or a straight-chain or branched-chain alkenyl group, and preferably represent a straight-chain or branched-chain alkyl group. Among them, it preferably represents a linear alkyl group having 1 to 3 carbon atoms, and more preferably represents a methyl group.
• R4 preferably represents a linear or branched alkyl group, a linear or branched alkenyl group or a phenyl group, more preferably a linear or branched alkyl group. Also, the terminal —CH 3 in the alkyl group or alkenyl group is preferably substituted with a carboxy group or a phenyl group.
• the number of carbon atoms in R4 is preferably 1 to 8, preferably 1 to 5, preferably 1 to 3, more preferably 1 or 2.
• R4 represents a methyl group
• R2 and R3 also preferably represent a methyl group
• general formula (3a) preferably represents an alkyltrimethylammonium skeleton.
• R4 represents an ethyl group
• the compound represented by general formula (3a) is preferably a cationic surfactant having a quaternary ammonium skeleton represented by general formula (3a-1).
• n represents the average number of added moles, and R4 has the same meaning as R4 in general formula (3a) according to claim 3.
• the number of carbon atoms represented by n is preferably 8 or more. The more the number of carbon atoms exceeds 8, the better the ink releasability.
• the specific number of carbon atoms is 8 octyl group with 9 carbon atoms, nonyl group with 10 carbon atoms, undecyl group with 11 carbon atoms, lauryl group with 12 carbon atoms, tridecyl group with 13 carbon atoms, myristyl with 14 carbon atoms C15 pentadecyl group, C16 cetyl group, C18 oleyl group, and stearyl group.
• Preferred groups for R4 are the same as in general formula (3a).
• These cationic surfactants having a quaternary ammonium skeleton are preferably of the quaternary ammonium skeleton salt type in which a salt is formed with a halogen, preferably form a salt with Cl- , more preferably with Br-. It is preferred to form a salt, more preferably with I ⁇ .
• a quaternary ammonium skeletal salt formed by forming a salt with a halogen accelerates the hydrolysis of the ink film by the nucleophilic action of the halogen, and is therefore considered to improve the releasability of the ink.
• alkyltrimethylammonium chloride-type dialkyldimethylammonium chloride-type, and alkylbenzalkonium chloride-type compounds are preferred.
• Specific products corresponding to general formula (3a) or (3a-1) include Nissan Cation MA, Nissan Cation SA, Nissan Cation BB, Nissan Cation FB, Nissan Cation PB-300, Nissan Cation ABT2-500, Nissan Cation AB, Nissan Cation AB-600, Nissan Cation VB-M Flake, Nissan Cation VB-F, Nissan Cation 2-DB-500E, Nissan Cation 2-DB-800E, Nissan Cation 2ABT, Nissan Cation 2-OLR, Nissan cation F 2 -50R, Nissan cation M 2 -100R, and Daiichi Kogyo Co., Ltd.
• cation TML manufactures cation TML, cation TMP, cation TMS, cation DDM-PG, cation BC-50, and cation TBB.
• Kotamine 24P, Kotamine 86P Conc, Kotamine 60W, Kotamine 86W, Sanizol C, and Sanizol B-50 are available from Kao Corporation, and Lipoguard C-50, Lipoguard T-28, and Lipoguard T-30 from Lion Corporation.
• the cationic surfactant preferably contains at least one compound represented by a primary to secondary alkanolamine skeleton, and contains at least one compound represented by a monoalkanolamine skeleton.
• the primary monoalkanolamine is preferably a lower alkanol having 1 to 4 carbon atoms, and specific examples thereof include monoethanolamine, 2-aminoisobutanol, and the like. Examples include N-methylethanolamine, 2-ethylaminoethanol, isopropanolamine and the like, but substances other than those exemplified can also be used as appropriate.
• these monoalkanolamine compounds can be used singly or in combination of two or more, and can also be used by mixing with water.
• These cationic surfactants having a monoalkanolamine skeleton are preferably in the form of monoalkanolamine salts forming salts with halogens, and preferably forming salts with Cl.sub.2.sup.-.
• the amount added is preferably 5% by weight or less, preferably 2% by weight or less, relative to the total amount of the ink remover.
• the lower limit of the surfactant is not particularly limited, and may be 0% by mass, but when a surfactant is contained, it is preferably 0.1% by mass or more.
• the temperature of the ink remover that is, the liquid temperature is not particularly limited. Since the cleaning effect of the release agent is higher when the liquid temperature is high, the temperature is preferably 30° C. or higher, preferably 40° C. or higher, and more preferably 50° C. or higher.
• the upper limit of the liquid temperature is not particularly limited as long as the liquid state can be maintained, but usually 90° C. or less is preferable.
• the liquid temperature is not too high in order to crush the plastic substrate more finely. , preferably 20° C. or less. The higher the friability, the better the ink releasability.
• the liquid temperature should be adjusted in consideration of the releasability effect of the ink remover and the crushability of the plastic substrate. Specifically, it is preferably used within the range of 10°C to 70°C.
• the equipment and method in the step of removing the ink layer using the ink remover are not particularly limited.
• a wet crusher, a colloid mill, a pulverizing mill, etc. can be exemplified when the plastic substrate is crushed at the same time as the ink is peeled off.
• wet crusher One example of a wet crusher used in the ink stripping method of the present invention is a wet crusher capable of simultaneously crushing, dispersing, mixing and pumping solids in a liquid. Specifically, a crusher having a mechanism for crushing solid matter in a liquid by shearing force and/or frictional force is preferred, and a crusher having a mechanism for crushing and pumping a plastic substrate is preferred. Examples of such wet crushers include wet crushing pumps, colloid mills, and pulverizing mills.
• the wet crushing pump used in the present invention preferably has a mechanism for crushing the solids with a fixed blade and a rotary blade while pumping the solids in the liquid. It is a mechanism that crushes in three stages by combining four parts, a shroud ring and a grid.
• the wet crushing pump crushes the plastic base material in three stages.
• the plastic substrate is roughly cut by the fixed blade cutting edge and the entrance edge of the rotary blade crushing impeller, and then stirred and pumped by the axial crushing impeller, and some plastic substrate is passed through the fixed blade shroud. It hits the cutting edge of the ring and is cut.
• the laminated film that has passed through the crushing impeller is further finely crushed and stirred between the grids, passed through the grid and pressurized by the pressure impeller, and then pumped to the next step.
• the pumping speed is not particularly limited, but considering the peeling of the ink layer and the peeling and separation efficiency when separating the plastic laminate in which the plastic substrate is laminated into each layer, it is 0.03 m 3 /min or more. preferable.
• the upper limit of the pumping speed is not particularly limited, and the standard operating speed of the apparatus, for example, 1.4 m 3 /min, is sufficient to separate the ink layer and separate the plastic laminate into single layers.
• the grid shape is not particularly limited. Since the grid diameter is related to the size of the laminated film after crushing, the grid diameter is preferably 0.1 to 50 mm, and more preferably 1 to 20 mm considering the crushing efficiency and the size of the laminated film after crushing. .
• wet crushing pumps include Husqvarna Zenoah's KD series, Nikuni's Sancutter series, Furukawa Sanki Systems' Disintegrator series, Aikawa Iron Works Inc.'s Incrusher series, and Sanwa Hydrotech's Scatter. can be exemplified.
• a colloid mill as used in the present invention is a machine used to reduce particle size in dispersed systems where the particles are suspended in a liquid.
• a colloid mill consists of a rotor-stator combination, where the rotor rotates at high speed relative to the fixed stator. High speed rotation is used to reduce particle size in liquids due to the high levels of shear produced.
• the crushing part of the colloid mill consists of a combination of a truncated cone-shaped rotor with teeth and a stator, and the rotor and stator have a tapered shape that narrows as it approaches the discharge port.
• the plastic base material is repeatedly subjected to strong shearing, compression, and impact in a ring-shaped gap that narrows as it approaches the discharge port, and is crushed.
• a specific colloid mill is not particularly limited as long as it is a dispersing machine generally called a colloid mill.
• An example can be Cavitron of the company.
• a grinding mill for use in the present invention is a machine used to grind solids in a system in which the solids are suspended in a liquid, and functions and looks like a food processor. Grinding mills, as used herein, are used to reduce the size of solids in a liquid due to the high level of shear produced by the high speed rotation of the rotating blades.
• the specific grinding mill is a batch type, and is not particularly limited as long as it is a machine that can put solids in a liquid and grind it with a rotary blade, but IKA's MultiDrive series and Osaka Chemical's Mighty Blender series , Waring series, Blender series can be exemplified.
• a plastic laminate in which dissimilar plastics are laminated can be separated into single-layer films and plastic substrates.
• most plastic laminates are provided with a printed ink film for displaying the product name or providing decorativeness, so in plastic laminates provided with an ink layer, can remove the ink layer more efficiently by crushing the plastic laminate in the release agent. In this way, by crushing the plastic laminate during peeling, the peeling and removal of the ink layer provided on the plastic laminate and the single-layer separation of the plastic laminate can be performed at the same time.
• the ink layer can be peeled off and removed by a simple process.
• gravure inks and flexographic inks are most commonly used for plastic laminated films, including those for food packaging.
• the printed ink layer can also be peeled off. can.
• the laminated film is laminated with a metal foil or vapor deposition film such as aluminum. In the present invention, the metal foil or vapor deposition film can also be peeled off or dissolved.
• Equipment and methods for recovering the ink layer and the plastic substrate after peeling of the ink layer are not particularly limited.
• a rotating drum screen or the like can be used.
• the plastic substrate having an ink layer used in the ink stripping method of the present invention is not particularly limited as long as the ink film is adhered to the plastic substrate.
• the ink layer is, for example, a printing ink printed with an organic solvent-based printing ink, water-based or active energy ray-curable ink using a gravure printing machine, a flexographic printing machine, an offset printing machine, an inkjet printing machine, or the like. It may be an ink layer for multi-color printing using a plurality of ink types.
• the type of ink is not particularly limited, and the ink layer can be removed regardless of the type of ink by using the ink remover of the present invention.
• the ink remover of the present invention contains an inorganic base such as sodium hydroxide or potassium hydroxide, the ink containing a resin that is weak against alkali, for example, the resin used in the ink containing nitrocellulose, or the resin used in the ink does not oxidize. It is preferable to contain a resin that has a strong adhesive because it becomes easier to peel off.
• the material and shape of the plastic base material are not particularly limited, and may be a single-layer structure or a plastic laminate in which different types of plastic are laminated.
• the plastic laminate used in the ink stripping method of the present invention is a plastic laminate having at least two layers, in which an ink layer, an adhesive layer, another plastic layer, a deposited film layer, and a metal foil are formed on a plastic substrate. It is a laminate in which a plurality of layers such as layers are laminated. Such laminates are not particularly limited, and include laminated films laminated and bonded with reactive adhesives used in food packaging and household goods.
• thermoplastic resins A laminated film laminated with an adhesive or a laminated film obtained by heat-sealing by an extrusion lamination method can also be separated and collected into single-layer films by peeling the ink layer by the ink peeling method of the present invention. can be done.
• a sheet-shaped or container-shaped laminate may be used.
• containers such as PET bottles, for example, use shrink labels, which are laminated films formed in a cylindrical shape, in order to display product names and provide decorativeness, and the shrink labels are consumed during recycling.
• the PET bottle main body and the shrink label are removed and discarded separately, but in the ink removing method of the present invention, the ink layer can be removed and removed even when the PET bottle main body and the shrink label are integrated. can be recovered.
• the ink can be removed, the shrink label can be separated from the PET bottle body, and the shrink label can be separated into individual single-layer films.
• a laminated film laminated and bonded with a reactive adhesive has an adhesive layer made of the reactive adhesive between at least two resin film layers, or between a plastic substrate and a metal foil or a deposited film layer. are often laminated.
• the resin film layer is expressed as (F)
• the metal foil layer of the metal foil or vapor deposition film layer is expressed as (M)
• the adhesive layer such as the reactive adhesive is expressed as (M).
• AD the following configuration can be considered as a specific mode of the laminated film, but of course it is not limited to this.
• the plastic laminate used in the ink peeling method of the present invention has a structure in which an ink layer is provided on a resin film layer, but the location where the ink layer is provided is not particularly limited.
• the ink layer may be provided on the outermost layer of the laminated film, or may be provided between the resin film layer (F) and the adhesive layer (AD).
• AD adhesive layer
• the ink layer and the adhesive layer are bonded more firmly, making it more difficult to separate the ink layer.
• the ink layer can be effectively peeled off even in the configuration of reverse printing. In particular, by crushing the plastic laminate in the ink remover, the ink layer can be peeled off and the layers constituting the plastic laminate can be separated at the same time.
• the laminated film may further have a paper layer, an oxygen absorbing layer, an anchor coat layer, a detachable primer layer for facilitating the removal of the ink, and the like.
• the resin film layer (F) functions as a base film layer (F1) or as a sealant layer (F2) that becomes a heat-sealed portion when forming a packaging material, when classified according to the required role.
• the resin film that serves as the base film layer (F1) includes polyolefin films such as low-density polyethylene, high-density polyethylene, linear low-density polyethylene, OPP (biaxially oriented polypropylene), and CPP (non-oriented polypropylene).
• polyolefin films such as low-density polyethylene, high-density polyethylene, linear low-density polyethylene, OPP (biaxially oriented polypropylene), and CPP (non-oriented polypropylene).
• polyester films such as polyethylene terephthalate (PET) and polybutylene terephthalate; polyamide films such as nylon 6, nylon 6,6 and metaxylene adipamide (N-MXD6); biodegradable films such as polylactic acid; Acrylonitrile-based film; Poly(meth)acrylic-based film; Polystyrene-based film; Polycarbonate-based film; Ethylene-vinyl acetate copolymer saponified product (EVOH)-based film; Films containing these pigments are included.
• a transparent vapor-deposited film obtained by vapor-depositing alumina, silica, or the like on these films may also be used.
• the surface of the film material may be subjected to various surface treatments such as flame treatment, corona discharge treatment, or chemical treatment such as primer.
• polyester films such as PET are easily soluble in the release agent of the present invention. It is an effective configuration for monolayer separation and recovery of
• plastic laminates such as PET/INK/AD/CPP are configured for reverse printing and use different types of plastic films, so it is difficult to separate and collect the ink and the single layer separation of the plastic film. Nevertheless, dissolution of the PET facilitates ink stripping and recovery of the CPP.
• Flexible polymer films that serve as the sealant layer (F2) include polyethylene films, polypropylene films, polyolefin films such as ethylene-vinyl acetate copolymers, ionomer resins, EAA resins, EMAA resins, EMA resins, EMMA resins, raw A film of decomposed resin is preferred.
• CPP unstretched polypropylene
• VMCPP aluminum-deposited unstretched polypropylene film
• LLDPE linear low-density polyethylene
• LDPE low-density polyethylene
• HDPE high-density polyethylene
• VMLDPE aluminum-deposited Non-low-density polyethylene film
• the metal foil layer (M) examples include foils of metals with excellent ductility such as gold, silver, copper, zinc, iron, lead, tin and alloys thereof, steel, stainless steel and aluminum. Since the metal foil layer (M) is easily dissolved in the release agent of the present invention, the structure having the metal foil layer (M) in the plastic laminate is effective for ink peeling, single-layer separation of the plastic film, and This configuration is effective for collection.
• the paper layer includes natural paper and synthetic paper.
• the first and second sealant layers may be formed of materials similar to the sealant layers described above.
• Other layers may contain known additives and stabilizers such as antistatic agents, non-reactive adhesive layers, easy-adhesion coating agents, plasticizers, lubricants and antioxidants.
• additives and stabilizers such as antistatic agents, non-reactive adhesive layers, easy-adhesion coating agents, plasticizers, lubricants and antioxidants.
• Step 1 Ink layer peeling step
• a plastic film provided with an ink layer is immersed in an ink remover.
• the immersion time is often within the range of 60 minutes.
• step 1 the number of times of immersion in the ink remover may be one or several times. After performing the immersion once, the step 2 of recovering the separated film may be performed, or after performing the immersion several times, the step 2 may be performed. Moreover, when performing multiple immersion in the process 1, you may change the kind and density
• step 1 it is preferable to crush the plastic film in the release agent using the wet crusher described above.
• the crushing facilitates the peeling of the plastic film, thereby improving the peelability of the ink layer.
• crushing of the film facilitates separation of each laminated layer into single layers, which promotes peeling of the ink layer.
• Step 2 Recovery step of the separated film
• Most of the ink layer separated from the film is not dissolved in the ink remover and remains as a residue in the ink remover. That is, in the ink remover in step 1, the peeled film and residues such as printing ink are floating. After these are removed from the washing liquid, the plastic films are separated and collected.
• plastics with a light specific gravity such as polyolefins such as polypropylene and polyethylene (floating matter), polyesters with a higher specific gravity than polyolefins, condensation synthetic films such as nylon, or metal Heavy objects such as foils are sorted out, and the heavy objects are removed.
• plastics with a light specific gravity such as polyolefins such as polypropylene and polyethylene (floating matter), polyesters with a higher specific gravity than polyolefins, condensation synthetic films such as nylon, or metal Heavy objects such as foils are sorted out, and the heavy objects are removed.
• the plastic collected in the washing and dehydrating process is washed and dehydrated, and the plastics with different specific gravities are separated by centrifugal separation.
• separated plastics containing vinyl chloride resin, polyethylene terephthalate, etc., having a specific gravity of 1 or more that sink in water, and separated plastics containing olefinic resins such as polyethylene and polypropylene, which do not contain vinyl chloride resin, can be separated.
• Step 3 Recovery and reuse of washing solution
• the ink stripping agent used in steps 1 and 2 is supplied to one or more cleaning agent recycling machines selected from a filter, a centrifuge, and an ultrafilter to recover the ink stripping agent, and the solid matter is It is reused after removal of condensate and residue.
• the cleaning agent recycling step may be operated continuously to separate the solids and residue concentrate from the ink stripping agent. can.
• Step 4 Drying the film
• the films are dried by one or more selected from reduced pressure heat drying, hot air drying, and pressurized compression drying in order to remove residual moisture. These can be used in combination.
• briquettes may be made using a pressurized press such as a briquette machine after or during drying of the film.
• Step 5 Production of recycled pellets
• the film pieces or briquettes dried in step 4 are put into single-screw and twin-screw kneaders to produce recycled pellets.
• the kneading conditions are not particularly limited, but it is preferable to operate at 180 to 280° C. in order not to greatly deteriorate the resin performance before recycling.
• the ink remover used in the present invention uses an inorganic base and a water-soluble solvent capable of dissolving the inorganic base.
• a water-soluble solvent the hydroxide ions generated from the inorganic base are not hydrated, so the nucleophilicity becomes high and the ink film is effectively peeled off.
• the water-soluble solvent since the water-soluble solvent has low polarity, it is considered that the ink layer peeling reaction progressed further in the hydrophobic environment.
• OPP Biaxially oriented polypropylene film 20um
• CPP unstretched polypropylene film 35um
• VMCPP aluminum deposition unstretched polypropylene film 25um
• PET polyethylene terephthalate film 12um (printing ink)
• INK1 Finart R507 primary color indigo (manufactured by DIC Graphics Co., Ltd.)
• INK2 Two-liquid curable ink (reactive adhesive) consisting of Finart R794 White G3 (manufactured by DIC Graphics Co., Ltd.) and curing agent CVL Hardener #10 (manufactured by DIC Co., Ltd.)
• AD1 solvent-based adhesive Dick Dry LX-470EL and SP-60 two-component adhesive (ether-based adhesive) (manufactured by DIC Corporation)
• AD2 Solvent-free adhesive Dick Dry 2K-SF-400A and HA-400B two-component adhesive (ester adhesive) (manufactured by
• Gravure inks which are printing inks, were each printed on a film "Film 1" using a proofer.
• Laminated films "LAM1" to "LAM4" were cut into a size of 2 cm x 6 cm to obtain test pieces.
• PRO1 Gently immersed in detergent for 30 minutes.
• PRO2 Stirred at 200 rpm for 10 minutes using Homodisper.
• PRO3 Sancutter C125H manufactured by Nikuni was used and pumped at 0.1 m3/min.
• the ink layer was easily removed in the example using the ink remover containing 20% by mass or more of the water-soluble solvent and the inorganic base.
• peelability could be confirmed by simply immersing PRO1.

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• 2022
  • 2022-02-24 EP EP22766831.6A patent/EP4306286A4/en active Pending
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