Recycling system and method for regenerating plastic laminates into recycled materials, and method for separating and recovering laminates

Abstract

The present invention provides a method for simultaneously removing the ink layer and separating the laminated film by crushing the laminated film in water or a detergent. [Solution] This is a recycling system for regenerating films having at least two layers, a plastic film layer and an ink layer applied to the plastic film layer, into recycled raw materials.The recycling system is characterized by having wet crushing equipment that crushes the film into pieces of 5 to 20 mm in water or a cleaning agent by crushing and pumping simultaneously, while peeling and removing the ink layer from the plastic film layer, and equipment that discharges and recovers the crushed mixture of plastic film layers from which the ink layer has been peeled and removed.

Description

[Technical Field]

[0001] The present invention relates to a recycling system and a recycling method for regenerating a plastic laminate into a recycled material, and a method for separating and recovering the laminate. [Background technology]

[0002] Currently, the recycling rate for plastic waste, which is the result of separate collection, is only 9% of all plastic produced worldwide. Of the 91% of plastic waste, 12% is incinerated, and 79% is disposed of in landfills or leaks into the environment (Non-Patent Document 1). One of the reasons for this persistently low recycling rate is the difficulty of implementing separate collection systems. To recycle plastics, waste plastics that contain multiple types of plastic materials, such as polyethylene (PE) and polypropylene (PP), must be separated and collected separately. However, many plastic products, including laminated films, are made up of multiple layers of plastic material bonded together, making it difficult to separate and collect each material. Therefore, there is a strong demand for the development of a recycling system that can easily separate and collect waste plastics.

[0003] Furthermore, it is difficult to recycle recycled plastic products into the same product due to cost considerations, and they generally deteriorate each time they are recycled, resulting in products of lower quality. One reason for the decline in quality of recycled plastic is the presence of inks and pigments as impurities in the plastic. However, many plastic products have printing on their surfaces, making it difficult to decolorize them during the recycling process, resulting in colored recycled plastic products. Recycled plastics containing such pigments and inks not only have significantly lower commercial value due to the coloring, but also tend to result in plastics that are physically degraded due to the impurities. Therefore, a recycling method that produces high-quality recycled plastic is needed.

[0004] To address these issues, Patent Document 1 proposes a recycling method in which the aluminum layer is dissolved from crushed multilayer film using alkali, the multilayer film is separated based on differences in specific gravity, and then the valuable components are separated by selectively melting the film in a solvent. Patent Document 2 proposes a process in which printed film is crushed, the ink is removed, the film is rinsed, and the film is dried, but both processes are long and complicated.

[0005] Furthermore, Patent Document 3 provides a method for removing ink from a printed rolled film using a solvent and a non-abrasive cloth, and Patent Document 4 provides a method for removing ink from a printed rolled film using a solvent, a brush, and a wiper blade, but these methods merely involve removing the ink from a rolled film to produce an unprinted film. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Science Advances 19 Jul 2017:Vol. 3, no. 7, e1700782 [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-205160 [Patent Document 2] Special Publication No. 2015-520684 [Patent Document 3] Special Publication No. 2016-509613 [Patent Document 4] Special Publication No. 2018-514384 Summary of the Invention [Problem to be solved by the invention]

[0008] In the prior art, separation of laminated films involves a dry crushing process followed by a deinking or separation process, which is a common, long and complicated process. Therefore, the problem to be solved by the present invention is to provide a recycling system that can simplify the process, improve productivity, and reduce costs. [Means for solving the problem]

[0009] As a result of extensive research to solve the above-mentioned problems, the inventors have discovered that the process of regenerating plastic laminates into recyclable raw materials can be simplified by incorporating wet crushing equipment into a recycling system, which crushes laminate films in a cleaning agent under wet conditions, and simultaneously separating the laminates into single layers during crushing.

[0010] That is, the present invention provides a film-forming material comprising: a plastic film layer; The ink layer has at least two layers provided on the plastic film layer. A recycling system for regenerating film into recycled materials. 、 By crushing and pumping simultaneously, the waste is Defu While crushing the film into 5-20mm pieces, Peel and remove the ink layer from the plastic film layer Wet crushing equipment and Plastic film with the ink layer peeled off A recycling system is provided that includes facilities for discharging and recovering the crushed mixture of the formation.

[0011] The present invention also provides a film comprising: a plastic film layer; The ink layer has at least two layers provided on the plastic film layer. A recycling method for regenerating film into recycled raw materials, using a wet crusher that can crush and pump simultaneously, Defu While shattering the film, Peel and remove the ink layer from the plastic film layer Step 1: Plastic film with the ink layer peeled off and 2. discharging and recovering the crushed mixture of layers.

[0012] The present invention also provides a film comprising: a plastic film layer; The ink layer has at least two layers provided on the plastic film layer. A method for separating and recovering films using a wet crusher that can crush and pump simultaneously, Defu While shattering the film, Peel and remove the ink layer from the plastic film layer Step 1 and Plastic film with the ink layer peeled off and (2) discharging and recovering the crushed mixture of layers.

[0013] The present invention also relates to a method for separating and recovering a substance, which is separated and recovered by the above separation and recovery method. Film The present invention provides a method for producing recycled plastic pellets, which comprises melting a crushed mixture and then molding it with a molding machine. [Effects of the Invention]

[0014] The present invention allows plastic laminates to be easily separated and shredded at the same time, and the shredded monolayer films can be collected, sorted, and reused. The present invention simplifies the recycling system process, improving productivity and reducing costs. DETAILED DESCRIPTION OF THE INVENTION

[0015] The recycling system, recycling method, and method for separating and recovering plastic laminates of the present invention are characterized by comprising step 1 of using a wet crusher that can crush and simultaneously pump in water or a detergent to separate the laminate into single layers while crushing the laminate in water, and step 2 of recovering a crushed mixture of each separated single layer.

[0016] First, the wet crushing equipment of the present invention will be described.

[0017] (wet crushing equipment) One example of the wet crushing equipment used in the recycling system of the present invention and the wet crusher used in step 1 for separating the laminate into single layers is a wet crusher that can simultaneously crush, disperse, mix, and pump solids in a liquid. Specifically, a crusher having a mechanism for crushing solids in a liquid using shear force and / or friction force is preferred, and a crusher having a mechanism for crushing and pumping plastic laminates is also preferred. Examples of such wet crushers include wet crushing pumps and colloid mills.

[0018] (Wet fracturing pump) The wet crushing pump used in the present invention preferably has a mechanism for crushing the solids using fixed blades and rotary blades while pumping the solids in the liquid, and a more preferred mechanism is one that crushes the solids in three stages using a combination of four parts: cutting blades, crushing impeller, shroud ring, and grid.

[0019] The wet-type crushing pump crushes plastic laminates in three stages. The plastic laminates are roughly cut by the fixed blade cutting edges and the inlet edge of the rotating blade crushing impeller, then stirred and pumped by the axial-flow crushing impeller, with some of the plastic laminates being cut by the blades of the fixed blade shroud ring. The laminated film that passes through the crushing impeller is further crushed and stirred between the grids, passes through the grid, is pressurized by the pressure impeller, and is pumped to the next process.

[0020] The pumping speed is not particularly limited, but considering the peeling and separation efficiency when peeling off the ink layer and separating the plastic laminate into each layer, it is recommended to use a pumping speed of 0.03 m 3 The upper limit of the pumping speed is not particularly limited, and is preferably the standard operating speed of the apparatus, for example, 1.4 m / min. 3 / min is sufficient to remove ink and separate plastic laminates into single layers.

[0021] The grid shape is not particularly limited. Since the grid diameter affects the size of the crushed laminate film, the grid diameter is preferably 0.1 to 50 mm, and in consideration of the crushing efficiency and the size of the crushed laminate film, it is more preferably 1 to 20 mm.

[0022] Specific examples of wet fracturing pumps include the KD series from Husqvarna Zenoah, the Suncuta series from Nikuni, the Disintegrator series from Furukawa Industrial Machinery Systems, the Incrusher series from Aikawa Iron Works, and the Scatter from Sanwa Hydrotech.

[0023] (Colloid Mill) The colloid mill used in this invention is a machine used to reduce the particle size in a dispersion system in which particles are suspended in a liquid. A colloid mill consists of a rotor and a stator combination, with the rotor rotating at high speed relative to the fixed stator. The high-speed rotation generates high levels of shear, which is used to reduce the particle size in the liquid.

[0024] The crushing section of the colloid mill consists of a toothed, truncated cone-shaped rotor and a stator, and the rotor and stator are tapered so that they narrow as they approach the discharge outlet. The laminated film is crushed in the ring-shaped gap that narrows as it approaches the discharge outlet, where it is subjected to repeated powerful shearing, compression, and impact.

[0025] Specific colloid mills are not particularly limited as long as they are dispersing machines generally called colloid mills, and examples include the Colloid Mill MK series from IKA, the WCM series from Iwaki, the PUC Colloid Mill series from Mountec, and the Cavitron from Eurotech.

[0026] By crushing a plastic laminate in water using the wet crusher, it is possible to separate the plastic laminate into single-layer films or plastic substrates. In addition to adhesives, most plastic laminates are provided with a printed ink layer for displaying product names and other information or for providing decorative features. The printed layer is often printed with an organic solvent-based printing ink, a water-based ink, or an active energy ray-curable ink using a gravure printer, flexographic printer, offset printer, inkjet printer, or the like. For plastic laminates provided with such an ink layer, the plastic laminate may be crushed in a detergent to more efficiently peel and remove the ink layer. Crushing the plastic laminate in a detergent allows for simultaneous peeling and removal of the ink layer provided on the plastic laminate and separation of the plastic laminate into single layers. For example, gravure ink and flexographic ink are the inks most commonly used for plastic laminate films, including those used for food packaging. The wet crushing process using a detergent can also peel off the printed ink layer. Furthermore, the laminated film may have a metal foil or vapor-deposited film such as aluminum laminated thereon, but in the present invention, the metal foil or vapor-deposited film can also be peeled off or dissolved.

[0027] (Water or cleaning agent) In the wet crushing equipment of the present invention and in step 1 for separating the laminate into single layers, the laminate is crushed in a liquid, i.e., in water or a detergent. As the detergent used in step 1, one of detergents 1 to 3 can be used alone, or two or more of them can be used in appropriate combination.

[0028] (Cleaning agent 1) Detergent 1 is an aqueous detergent containing water and an inorganic base. Aqueous sodium hydroxide solution or aqueous potassium hydroxide solution is more preferred. The aqueous sodium hydroxide solution or aqueous potassium hydroxide solution preferably has a concentration of 0.1 to 10% by mass, more preferably 0.1 to 5% by mass. The pH of the solution is preferably 10 or higher.

[0029] (Cleaning agent 2) Cleaning agent 2 is a cleaning agent containing 20 mass % or more of alkylene glycol alkyl ether represented by general formula (1). R 1 -O-[CH2-CH(X)-O]n 1 -R 2 (1) (In general formula (1), R 1 represents an alkyl group having one or more carbon atoms, and R 2 represents an alkyl group having one or more carbon atoms or hydrogen, 1 represents an integer of 1 to 3, and X represents hydrogen or a methyl group. Among the alkylene glycol alkyl ethers represented by the general formula (1), water-soluble alkylene glycol alkyl ethers are more preferred.

[0030] Examples of the water-soluble alkylene glycol alkyl ether represented by general formula (1) include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol methyl ethyl ether, ethylene glycol methyl propyl ether, ethylene glycol ethyl propyl ether, ethylene glycol monobutyl ether, ethylene glycol-tert-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl propyl ether, diethylene glycol ethyl propyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol dimethyl ether, and propylene glycol diethyl ether.

[0031] These alkylene glycol alkyl ethers can be used alone or in appropriate combinations of two or more, or can be mixed with water for use. There is no particular problem if the alkylene glycol alkyl ether content is 20% by mass or more, but when water is the medium, it is preferably 30% by mass or more, and most preferably 40% by mass or more. On the other hand, the upper limit may be 100% by mass, but it is preferable to use water as the medium from the viewpoint of environmental impact and safety.

[0032] Among the water-soluble alkylene glycol alkyl ethers represented by the general formula (1), alkylene glycol monoalkyl ethers represented by the general formula (2) are more preferred. R1 -O-[CH2-CH(X)-O]n 1 -R 2 (1) (In general formula (2), R 2 represents an alkyl group having one or more carbon atoms, and n 2 represents an integer of 1 to 3, and X represents hydrogen or a methyl group. The alkylene moiety of the alkylene glycol monoalkyl ether represented by general formula (2) is more preferably methylene, followed by ethylene, then propylene, and then butylene, in that the ink layer is more easily removed. That is, the order of preference is methylene glycol monoalkyl ether, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, and butylene glycol monoalkyl ether.

[0033] The repeating glycol moiety of the alkylene glycol monoalkyl ether represented by general formula (2) is more preferably n = 1, in that it makes the ink layer easier to remove, followed by n = 2 and then n = 3. That is, among the repeating ethylene moieties, the most preferred are ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether, and triethylene glycol monoalkyl ether, in that order.

[0034] The monoalkyl moiety of the alkylene glycol monoalkyl ether represented by general formula (2) is more preferably monomethyl, followed by monoethyl, then monopropyl, and then monobutyl, in that the ink layer is more easily removed. That is, the order of preference is alkylene glycol monomethyl ether, alkylene glycol monoethyl ether, alkylene glycol monopropyl ether, and alkylene glycol monobutyl ether.

[0035] Among these, diethylene glycol monomethyl ether and diethylene glycol monoethyl ether are particularly preferred in terms of cleaning properties, environmental characteristics, and flammability.

[0036] (Cleaning agent 3) The cleaning agent 3 is a cleaning agent containing 20 mass % or more of a primary or secondary monoalkanolamine having a boiling point of 150 to 200°C.

[0037] Examples of primary monoalkanolamines include monoethanolamine and 2-aminoisobutanol, and examples of secondary monoalkanolamines include N-methylethanolamine, 2-ethylaminoethanol, and isopropanolamine. However, primary and secondary monoalkanolamines other than those exemplified above can also be used as appropriate as long as they have a boiling point within the range of 150 to 200°C.

[0038] These primary or secondary monoalkanolamines can be used alone or in appropriate combinations of two or more, or they can be mixed with water for use. There is no particular problem if the content of primary or secondary monoalkanolamine is 20% by mass or more, but when water is the medium, it is preferably 30% by mass or more, and most preferably 40% by mass or more. On the other hand, the upper limit may be 100% by mass, but from the viewpoint of environmental impact and safety, it is preferable to use water as the medium.

[0039] (surfactant) The cleaning agents 1 to 3 may contain a surfactant. Examples of the surfactant include various anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, nonionic surfactants are preferred.

[0040] Examples of nonionic surfactants include 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 esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acid amides, fatty acid alkylolamides, alkylalkanolamides, acetylene glycol, oxyethylene adducts of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymers. Of these, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid alkylolamides, acetylene glycol, oxyethylene adducts of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymers are preferred.

[0041] These surfactants can be used alone or in combination of two or more. When a surfactant is added, the amount added is preferably in the range of 0.001 to 2 mass % of the total amount of the detergent, and more preferably 0.001 to 1.5 mass %.

[0042] (liquid temperature) The liquid temperature of the water or detergent used in step 1 of the separation and recovery method of the present invention is not particularly limited as long as it can maintain a liquid state, but it is usually preferable to carry out the process at a liquid temperature of 15 to 90°C. A higher liquid temperature provides a more effective cleaning effect. A liquid temperature of 40°C or higher is preferred, and a more effective liquid temperature is 65°C or higher, more preferably 85°C or higher.

[0043] (plastic laminate) The plastic laminate of the present invention, which is separated and recovered using the wet crushing equipment, is a plastic laminate having at least two or more layers, i.e., a laminate having multiple layers, such as an ink layer, an adhesive layer, and another plastic layer, on a plastic substrate. In other words, the plastic laminate of the present invention is a laminate having at least a plastic substrate (F1) made of a plastic film or the like, and a layer selected from an ink layer, an adhesive layer, and another plastic film layer (F2) different from F1. Examples of such laminates include, without limitation, laminate films laminated with reactive adhesives used for food packaging and household goods. However, laminate films laminated with non-reactive adhesives, such as thermoplastic resin adhesives, and laminate films obtained by heat fusion using an extrusion lamination method can also be separated and recovered into individual monolayer films using the separation and recovery method of the present invention. Furthermore, laminates in the form of sheets or containers may also be used. In other words, a feature of the present invention is that plastic laminates having various types of resin layers discarded through recycling can be processed together without the need for special re-sorting.

[0044] Furthermore, the laminate of the present invention is not limited to a structure in which multiple films are laminated together, but also includes, for example, a structure having only a plastic substrate (F1) and a printed layer. According to the present invention, the printed layer can be easily removed, thereby improving the quality of recycled plastics.

[0045] Furthermore, shrink labels, which are laminated films formed into a cylindrical shape, are used on containers such as PET bottles to display product names and add decorative features. When recycling, consumers often peel off the shrink label and discard the PET bottle body and shrink label separately. However, the separation and recovery method of the present invention makes it possible to separate the shrink label from the PET bottle body even when the PET bottle body and shrink label are integrated, and to separate the shrink label into each single-layer film.

[0046] The laminated film laminated with a reactive adhesive that is the target of this separation and recovery method often has an adhesive layer made of the reactive adhesive laminated between at least two resin film layers or metal foil or vapor-deposited film layers. Specifically, in the laminated film, if the resin film layer is represented as (F), the metal foil layer of the metal foil or vapor-deposited film layer is represented as (M), and the adhesive layer of the reactive adhesive or the like is represented as (AD), the following configurations are possible as specific embodiments of the laminated film, but of course, they are not limited to these. (F) / (AD) / (F), (F) / (AD) / (F) / (AD) / (F), (F) / (AD) / (M) / (AD) / (F), (F) / (AD) / (M), (F) / (AD) / (M) / (F), (F) / (AD) / (F) / (AD) / (M) / (AD) / (F), (F) / (AD) / (M) / (AD) / (F) / (AD) / (F), (M) / (AD) / (M), (M) / (AD) / (F) / (AD) / (M), (AD) / (F) / (AD) / (M), (AD) / (F) / (AD) / (F) / (AD), etc.

[0047] The laminated film that is the target of this separation and recovery method may further have a paper layer, an oxygen absorbing layer, an anchor coat layer, a printed layer, and the like.

[0048] When a printed layer (ink layer) is provided, the location of the ink layer is not particularly limited. For example, the ink layer may be provided on the outermost layer of the laminate film, or may be provided between the resin film layer (F) and the adhesive layer (AD). When the ink layer is provided between the resin film layer (F) and the adhesive layer (AD) (reverse printing), the ink layer and the adhesive layer are more strongly bonded, making peeling of the ink layer difficult. However, the method of the present invention allows for efficient separation of the laminate into single layers and removal of the ink layer simultaneously.

[0049] The resin film layer (F) can be classified according to the required role, and functions as a base film layer (F1) or a sealant layer (F2) that becomes a heat-sealed portion when forming a packaging material.

[0050] Examples of resin films that can be used as the base film layer (F1) include 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; polyacrylonitrile films; poly(meth)acrylic films; polystyrene films; polycarbonate films; saponified ethylene-vinyl acetate copolymer (EVOH) films; polyvinyl alcohol films; and films containing these pigments, such as K-coats of polyvinylidene chloride. Transparent vapor-deposited films obtained by vapor-depositing alumina, silica, or the like onto these films may also be used.

[0051] The surface of the film material may be subjected to various surface treatments such as flame treatment, corona discharge treatment, or chemical treatment using a primer or the like.

[0052] Preferred flexible polymer films for the sealant layer (F2) include polyethylene film, polypropylene film, polyolefin films such as ethylene-vinyl acetate copolymer, ionomer resin, EAA resin, EMAA resin, EMA resin, EMMA resin, and biodegradable resin films. Examples of generic names include CPP (non-oriented polypropylene) film, VMCPP (aluminum-deposited non-oriented polypropylene film), LLDPE (linear low-density polyethylene), LDPE (low-density polyethylene), HDPE (high-density polyethylene), VMLDPE (aluminum-deposited non-low-density polyethylene film), and films containing these pigments. The film surface may be subjected to various surface treatments, such as flame treatment, corona discharge treatment, or chemical treatment with a primer.

[0053] Examples of the metal foil layer (M) include foils of metals with excellent ductility, such as gold, silver, copper, zinc, iron, lead, tin and alloys thereof, steel, stainless steel, and aluminum.

[0054] The paper layer may be made of natural paper, synthetic paper, etc. The first and second sealant layers may be made of the same material as the sealant layer described above.

[0055] Other layers may contain known additives and stabilizers, such as antistatic agents, non-reactive adhesive layers, easy-adhesion coating agents, plasticizers, lubricants, antioxidants, and the like.

[0056] Next, a specific embodiment of a recycling system using the wet crushing equipment will be described. Note that the recycling system described below is an example, and the present invention is not limited to this.

[0057] (1) Sorting of waste plastic Waste plastics, including readily available plastic packaging, are collected at recycling facilities to be recycled into recycled materials. If the collected waste plastic contains contaminants such as soil, glass, ceramics, or metal, it is preferable to remove these contaminants. It is also preferable to separate the waste plastic into molded products and film or sheet-like plastic laminates. Removal of contaminants and sorting of plastics can be achieved, for example, by manual inspection and sorting, sieving to remove small contaminants, magnetic sorting to remove metals, wind-powered sorting to separate plastics and contaminants with different specific gravities, and sensor-based sorting. Depending on the level of contaminants in the waste plastic, sorting may not be necessary.

[0058] (2) Cutting The selected plastic laminate may be cut into plastic pieces, for example, about 30 cm square. By passing through this cutting process, crushing in a wet crusher in the next step can be carried out more efficiently. A known crusher can be used for the cutting, and examples include impact crushers such as hammer crushers and rotary crushers, shredders, cutters, etc. The size and shape of the cut plastic laminate pieces are not particularly limited, but the maximum length of the plastic pieces is, for example, preferably 50 cm or less, preferably 30 cm or less, preferably 20 cm or less, and preferably 10 cm or less. After the cutting process, the plastic sorting process performed in (1) above may be carried out again, or the cutting in (2) may be carried out before the waste plastic sorting in (1) above.Alternatively, the next process of using a wet crusher may be carried out without cutting.

[0059] (3) Separation process of plastic laminate (Process 1) The collected plastic laminate pieces are sequentially fed into a wet crusher filled with a cleaning liquid heated to about 85°C. The cleaning liquid may be water or a detergent. For example, a laminate film roll is cut into pieces of about 30 cm square, which are drawn into the crushing section by suction of the wet crusher and crushed into pieces of about 5 to 20 mm, and then sent to the next process in pieces of 0.03 m. 3 / min. At this time, the film fed in is subjected to high shear when it is crushed, causing the laminated film to separate into individual film layers. If the laminated film has an ink layer, the ink layer is also peeled off and removed from the film due to the high shear caused by crushing.

[0060] Even if the object to be wet-shredded is not a laminated film roll but individual film bags collected from the market, they can be fed into the wet-shredder in the same state as they are collected.

[0061] In step 1, the wet-crushing step may be performed once or several times. That is, after wet-crushing is performed once, step 2 may be performed in which the separated monolayer films of each layer are recovered, or wet-crushing may be performed several times before step 2 is performed. Furthermore, when multiple wet-crushing steps are performed in step 1, the cleaning agent for each step may be changed. Furthermore, known steps such as water washing, draining, dehydration, and drying may be appropriately added between the steps.

[0062] (4) Recovery process of the crushed mixture of each separated single layer (Step 2) When a laminated film having an adhesive layer is wet-shredded in step 1, the adhesive layer that separates from the laminated film often does not dissolve in water or detergent, and remains as a residue in the cleaning solution. That is, in the water or detergent in step 1, the separated monolayer film of each layer, along with residues of adhesive, printing ink, metal foil, etc., are floating or dissolved. After removing these from the water or detergent, they are separated and recovered.

[0063] One specific example of this method involves flotation separation, which separates plastics with low specific gravity, such as polyolefins like polypropylene and polyethylene, from heavier materials like condensation synthetic films like polyester and nylon, or metal foils, which have heavier specific gravities than polyolefins. The heavier materials are then removed, and the recovered plastics are washed and dehydrated in a washing and dehydration process, after which plastics with different specific gravities are separated by centrifugation. For example, plastics can be separated into plastics containing vinyl chloride resins and polyethylene terephthalate, which have a specific gravity of 1 or higher, and plastics containing olefin-based resins like polyethylene and polypropylene, which do not contain vinyl chloride resin. Further separation is possible by changing the specific gravity of the liquid used in flotation separation, such as the ratio of water to organic solvents or salts.

[0064] After rough separation and recovery by gravity separation, more advanced separation may be performed using electrostatic separation, which utilizes the inherent charging properties of plastics. One example of a specific method is to separate a pre-charged plastic mixture by dropping it between parallel plate electrodes to which a voltage is applied. This method can separate combinations of plastics with small differences in specific gravity, which are difficult to separate using gravity separation.

[0065] (5) Recovery and reuse of cleaning solution (Step 3) The water or detergent used in steps 1 and 2 is supplied to one or more detergent recycling machines selected from a filter, centrifuge, and ultrafilter to recover the detergent, and the solids are removed before being reused. While the wet crushing step and gravity separation step are performed in steps 1 and 2, the water or detergent recycling step can be continuously operated to separate the solids from the detergent.

[0066] (6) Drying of plastic separated material (Step 4) After the single-layer plastic separated product obtained by separating the laminate in step 2, specifically the various single-layer film pieces, is collected, the film pieces are dried using one or more methods selected from reduced-pressure heat drying, hot air drying, and pressurized compression drying to remove residual moisture. These methods can also be used in combination. As a pretreatment for producing recycled pellets in step 5, briquettes can be produced using a pressurized compressor such as a briquetting machine after or during the drying of the film pieces.

[0067] (7) Preparation of recycled pellets (Step 5) The film pieces or briquettes dried in step 4 are fed into a single-screw or twin-screw molding machine to produce recycled pellets. The kneader conditions are not particularly limited, but it is preferable to operate the kneader at 180 to 280°C to prevent significant deterioration of the resin performance before recycling.

[0068] In the present invention, the reason why "Step 1," i.e., separating the plastic laminate into individual layers while crushing the plastic laminate in water or a detergent, and further, peeling and removing the ink layer if the plastic laminate has one, can be achieved simultaneously is presumably because the high shear force exerted by the wet crushing pump when the plastic laminate is crushed is effective not only in crushing the film but also in peeling the laminate and removing the ink layer. Because the shear force is so high that it crushes the laminate, this cannot be easily achieved with a high-speed mixer, ultrasonic cleaner, etc. [Example]

[0069] The contents and effects of the present invention will be explained in more detail below with reference to Examples. The films, printing inks, reactive adhesives, and organic solvents used as raw materials in each Example and Comparative Example are also shown below.

[0070] (Film used for laminating film) OPP: Biaxially oriented polypropylene film 20um PET: Polyethylene terephthalate film 12um OPA: Polyamide film (nylon) film 15um CPP: Non-oriented polypropylene film 35um LLDPE: Unstretched linear low density polyethylene film 60um VMCPP: Aluminum-coated non-oriented polypropylene film 25um (printing ink) Solvent-based gravure ink for surface printing INK1: DIC Graphics surface printing ink Glossa BM709 white Solvent-based gravure ink for reverse printing INK2: DIC Graphics reverse printing ink Finart R794 White S Water-based reverse printing flexographic ink INK3: DIC Graphics Marine Flex LM R507 Primary Blue (reactive adhesive) AD1: Solvent-based adhesive, Dick Dry LX-401A and SP-60, two-component adhesive (ether-based adhesive) AD2: Solvent-free adhesive, Dick Dry 2K-SF-400A and HA-400B, two-component adhesive (ester adhesive) (Laminated film manufacturing method) The laminated film was created by printing on the target film using a printing method and then laminating the target film. The film layer structure, reactive adhesive, and printing ink types were combined as shown in Table 1.

[0071] (Printing method) The printing inks, gravure ink and flexographic ink, were applied to the film "Film 1" using a proofer.

[0072] (Lamination method) For LAM3 to LAM7, the reactive adhesive "AD" was applied to the surface of the film "Film1" on which the printing ink was applied or the surface opposite to the surface on which the printing ink was applied, at a solid content of 3 g / m2 using a laminator. 2The laminated film was then subjected to an aging reaction at 40°C for 72 hours. Laminated films "LAM1" to "LAM7" shown in Table 1 were obtained. Blank spaces indicate that no structure was present.

[0073] [Table 1]

[0074] The laminated films "LAM1" to "LAM7" were cut into 30cm x 30cm pieces to obtain test pieces.

[0075] (Cleaning process) PRO1: Nikuni Sancuta C125H is used, 0.1m 3 / min. PRO2: Immersed in an ultrasonic cleaner at 28 kHz for 30 minutes. PRO3: Stirred using a Homodisper at 2000 rpm for 30 minutes. PRO4: Iwaki Colloid Mill WCM, 0.03m 3 / min. PRO5: Using an EarthTechnica high-speed mixer, model FS2, the mixture was stirred at 2000 rpm for 30 minutes.

[0076] The results of the ink peeling and laminated film separation tests are shown in Tables 2 and 3. In Examples 1 to 5 and Comparative Examples 1 to 4, water was used in the washing step.

[0077] (Removability of laminated film) Result 1 in the table shows the state of ink peeling from the laminate film and the state of separation of the laminate film. After the laminate film was washed and dried in each washing process, the ink peelability of the printed area and the peelability of the laminate film were determined by calculating the area through image processing of photos taken with an optical microscope and calculating the removal rate using the following formula. Peeling rate (%) = (1 - ink-adhered or film-laminated area after cleaning / ink-adhered or film-laminated area before cleaning) x 100 ○: 75% or more of the printed or laminated area peeled off. △: 50 to 74% of the printed or laminated area peeled off. ×: 0 to 25% of the printed or laminated area peeled off. The symbol ○ indicates a range where there is no practical problem.

[0078] (Degree of crushing of laminated film) Result 2 in the table shows the state of fracture of the laminated film. After the laminated film was washed and dried in each washing step, the length of the laminated film was visually measured using a ruler to check the state of fracture of the laminated film. ○: The film is broken and the short side is 20 mm or less. ×: The film was not broken and retained its original shape.

[0079] [Table 2]

[0080] [Table 3]

[0081] PRO1, a wet crusher, was able to crush and peel off the laminate at the same time, but PRO2 and PRO3, which are not wet crushers, were unable to do so. In Result 1 of Examples 1 to 5, 100% peeling between Film 1 and Film 2 was confirmed, demonstrating that PRO1 is excellent at peeling off plastic layers and can fully separate different plastics.

[0082] Subsequently, laminated films "LAM8 to LAM15" shown in Table 4 were obtained. Note that blank spaces indicate that no structure was present.

[0083] [Table 4]

[0084] The laminated films "LAM8" to "LAM15" were cut to a size of 30 cm x 30 cm to obtain test pieces.

[0085] (Cleaning agent composition) The cleaning agents filled into the wet crusher were combined as shown in Table 5, and "CL1" to "CL8" were obtained. The numbers in the table indicate mass %. Blank spaces indicate that the agent was not blended.

[0086] [Table 5]

[0087] Noigen XL-41 in the table is a nonionic surfactant manufactured by Daiichi Kogyo Seiyaku. Tables 6 to 8 show the results of the ink peeling and laminated film separation tests.

[0088] (Removability with cleaning agents) Result 1 in the table shows the state of ink peeling from the laminate film and the state of separation of the laminate film. After the laminate film was washed and dried in each washing process, the ink peelability of the printed area and the peelability of the laminate film were determined by calculating the area through image processing of photos taken with an optical microscope and calculating the removal rate using the following formula. Peeling rate (%) = (1 - ink-adhered or film-laminated area after cleaning / ink-adhered or film-laminated area before cleaning) x 100 ○: 100% of the printed or laminated area peeled off. ○△: 75 to 99% of the printed or laminated area peeled off. △: 50 to 74% of the printed or laminated area peeled off. △×: 25 to 49% of the printed or laminated area peeled off. ×: 0 to 25% of the printed or laminated area peeled off. The marks ○, ○ and △ indicate ranges that pose no practical problems.

[0089] (Degree of crushing of laminated film) Result 2 in the table shows the state of fracture of the laminated film. After the laminated film was washed and dried in each washing step, the length of the laminated film was visually measured using a ruler to check the state of fracture of the laminated film. ○: The film is broken and the short side is 20 mm or less. △: The film was crushed to a size of 21 to 50 mm in the short side direction. ×: The film was not broken and retained its original shape. The marks ◯ and △ indicate a range in which there is no practical problem.

[0090] [Table 6]

[0091] [Table 7]

[0092] [Table 8]

[0093] The wet crushers PRO1 and 4 were able to crush all of the laminated film structures LAM8 to 15, but PRO2, 3 and 5, which were not wet crushers, were unable to crush them.

[0094] The cleaner containing an alkaline solution of 1% by weight of sodium hydroxide was able to remove the ink and separate the film from the laminated film in PRO1 and 4. In PRO2, 3, and 5, the ink was removed from LAM8 but it was not able to break it down.

Claims

1. A recycling system for regenerating a film having at least two layers, a plastic film layer and an ink layer provided on the plastic film layer, into a recycled material, comprising: wet crushing equipment that crushes the film into pieces of 5 to 20 mm in a cleaning agent by simultaneously crushing and pumping the film, while peeling and removing the ink layer from the plastic film layer; Equipment that discharges and collects the crushed mixture of plastic film layers from which the ink layer has been peeled off. and In the wet crushing equipment, a wet crusher is used that can crush and pump simultaneously, and crushes by shear force and / or friction force, A recycling system characterized in that the temperature of the cleaning agent in the process of peeling and removing the ink layer from the plastic film layer while crushing the film in the cleaning agent is 15 to 90°C.

2. 2. The recycling system according to claim 1, wherein the cleaning agent is an aqueous cleaning agent selected from the group consisting of (1) to (3). (1) An aqueous cleaning agent containing water and 0.1 to 10% by mass of an inorganic base. (2) An aqueous detergent containing 20% by mass or more of an alkylene glycol alkyl ether represented by general formula (1). R １ -O-[CH ２ -CH(X)-O]n １ -R ２ (1) (In the general formula, R １ represents an alkyl group having one or more carbon atoms, R ２ represents an alkyl group having one or more carbon atoms or hydrogen, １ represents an integer of 1 to 3, and X represents hydrogen or a methyl group. (3) An aqueous cleaning agent containing 20% by mass or more of a primary or secondary monoalkanolamine having a boiling point of 150 to 200°C.

3. The discharge speed in the process of discharging and recovering the crushed mixture of the plastic film layer is 0.03 m ３ 3. The recycling system according to claim 1, wherein the recycling rate is 1 / min or more.

4. 4. The recycling system according to claim 1, wherein the film is a laminated film further having another layer selected from a plastic film layer, a metal foil layer, and a vapor-deposited film layer.

5. 5. The recycling system according to claim 4, further comprising a facility for separating the laminated film into single layers by the wet crushing facility and then separating the single layers.

6. The recycling system according to any one of claims 1 to 5, wherein after the film is separated from the waste plastic, the film is wet-shredded.

7. The recycling system according to any one of claims 1 to 6, wherein the crushed mixture of films separated and recovered by the wet crushing equipment is melted and then molded by a molding machine.

8. A recycling method for regenerating a film having at least two layers, a plastic film layer and an ink layer provided on the plastic film layer, into a recyclable material, comprising: A process 1 in which the ink layer is peeled off and removed from the plastic film layer while crushing the film in a cleaning agent using a wet crusher capable of crushing and pressure-feeding at the same time; Step 2: Discharge and collect the crushed mixture of the plastic film layer from which the ink layer has been peeled off. and In the step 1, a wet crusher is used which can crush and pump simultaneously and crush by shear force and / or friction force, A recycling method characterized in that the liquid temperature of the cleaning agent in step 1 is 15 to 90°C.

9. A method for separating and recovering a film having at least two layers, namely, a plastic film layer and an ink layer provided on the plastic film layer, comprising: A process 1 in which the ink layer is peeled off and removed from the plastic film layer while crushing the film in a cleaning agent using a wet crusher capable of crushing and pressure-feeding at the same time; Step 2: Discharge and collect the crushed mixture of the plastic film layer from which the ink layer has been peeled off. and In the step 1, a wet crusher is used which can crush and pump simultaneously and crush by shear force and / or friction force, The method for separating and recovering plastic laminates, wherein the liquid temperature of the cleaning agent in step 1 is 15 to 90°C.

10. A method for producing recycled plastic pellets, comprising melting the crushed film mixture separated and recovered by the method of claim 9 and molding it in a molding machine.

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