Removal method and method for manufacturing recycled film

Abstract

The present invention provides a removal method that can remove a functional layer from a film containing a functional layer with high precision, and a method for manufacturing recycled film using the said removal method. [Solution] The removal method involves removing the functional layer from a film containing the functional layer. This removal method includes the steps of processing the film by irradiating the functional layer with high-energy rays, and removing the functional layer from the processed film.

Description

Technical Field

[0001] The present invention relates to a removal method and a method for manufacturing a recycled film.

Background Art

[0002] Japanese Patent No. 6849141 (Patent Document 1) discloses a method for manufacturing a heat-shrinkable film. In the manufacture of this heat-shrinkable film, a resin composition containing at least one of fluff and rep pellets obtained from packaging materials as starting materials is used. The packaging materials, which are the starting materials for fluff and rep pellets, have a printed layer (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003] [[ID=,22]]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Many film products are provided with functional layers such as printed layers. Therefore, many film waste materials also contain foreign substances such as colorants. When manufacturing a recycled film using film waste materials, the foreign substances contained in the film waste materials affect the quality of the recycled film. In order to suppress the influence of the foreign substances contained in the film waste materials on the quality of the recycled film, it is conceivable to remove the functional layer from the film waste materials in advance. However, it is not always easy to remove the functional layer with high precision. The above Patent Document 1 does not disclose a solution to such a problem. <0,000026>

[0005] The present invention has been made to solve such problems, and an object thereof is to provide a removal method capable of removing a functional layer from a film containing the functional layer with relatively high precision, and a method for manufacturing a recycled film using the removal method. [Means for solving the problem]

[0006] A removal method according to a certain aspect of the present invention removes a functional layer from a film containing a functional layer. This removal method includes the steps of processing the film by irradiating the functional layer with high-energy rays, and removing the functional layer from the processed film.

[0007] This removal method allows for easier removal of the functional layer by irradiating it with high-energy rays, thus enabling more precise removal of the functional layer from the film.

[0008] In this removal method, the step of removing the functional layer may include the step of removing the functional layer using a desorption solution.

[0009] According to this removal method, the functional layer is irradiated with high-energy rays, which facilitates the penetration of the desorption solution into the interface between the functional layer and the film body, allowing the functional layer to be removed from the film with greater precision.

[0010] In this removal method, the eluent may be an alkaline solution, and the pH of the alkaline solution may be 8 or higher and 11 or lower.

[0011] According to this removal method, the functional layer is irradiated with high-energy rays, which makes it easier for the alkaline solution to penetrate the interface between the functional layer and the film body. Therefore, even if the alkaline solution is weakly alkaline, the functional layer can be removed from the film with greater precision.

[0012] In this removal method, the step of removing the functional layer may include the step of removing the functional layer by applying a physical process to it.

[0013] This removal method allows for more precise removal of the functional layer from the film because the functional layer is irradiated with high-energy rays, making it easier to perform physical treatment at the interface between the functional layer and the film body.

[0014] In this removal method, the step of removing the functional layer may include the step of washing the film.

[0015] This removal method involves cleaning the film, which allows for the washing away of any debris remaining on the film, such as that caused by the functional layer.

[0016] In this removal method, the film may include a first region on which a functional layer is laminated and a second region on which no functional layer is laminated, and in the processing step, high-energy rays may be irradiated to the first region but not to the second region.

[0017] This removal method prevents high-energy rays from irradiating the second region, thus shortening the time required for film processing compared to cases where high-energy rays are irradiated to both the first and second regions.

[0018] A method for manufacturing a recycled film according to another aspect of the present invention includes the steps of: manufacturing a film from which the functional layer has been removed by using the above-described removal method; and manufacturing a recycled film by using the film from which the functional layer has been removed.

[0019] According to this method for manufacturing recycled film, since the recycled film is produced based on a film from which the functional layer has been removed with high precision, it is possible to produce a higher quality recycled film. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a removal method that can remove a functional layer from a film containing a functional layer with relatively high precision, and a method for manufacturing recycled film using the removal method.

Brief Description of the Drawings

[0021] [Figure 1] It is a diagram schematically showing the configuration of a resource recycling system. [Figure 2] It is a plan view schematically showing an example of a printed film. [Figure 3] It is a diagram schematically showing the III-III cross section of FIG. 2. [Figure 4] It is a diagram schematically showing a part of the front of a printing layer removing device. [Figure 5] It is a flowchart showing an example of the manufacturing procedure of a recycled film. [Figure 6] It is a flowchart showing an example of the processing procedure performed in step S100 of FIG. 5. [Figure 7] It is a diagram schematically showing a cross section of an example of the recycled film to be manufactured. [Figure 8] It is a plan view schematically showing another example of a printed film. [Figure 9] It is a flowchart showing an example of the irradiation procedure of high energy rays by an irradiation device.

Embodiments for Carrying Out the Invention

[0022] Hereinafter, embodiments according to one aspect of the present invention (hereinafter, also referred to as "the present embodiments") will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions will not be repeated. Also, for ease of understanding, each drawing is schematically drawn with appropriate omissions or exaggerations of the subject.

[0023] [1. Configuration of Resource Recycling System, etc.] In recent years, ocean pollution caused by plastic waste has become a global problem. As a means to address such problems, resource recycling has attracted attention.

[0024] Figure 1 is a schematic diagram showing the configuration of a resource recycling system S1 that uses a method for manufacturing recycled film according to this embodiment. Referring to Figure 1, in the resource recycling system S1, for example, a resin film with a pattern printed on it (hereinafter also referred to as "printed film") is recycled and a new film is manufactured. The pattern consists of, for example, a design, letters, symbols (e.g., a barcode), or a combination thereof. The printed film is a packaging material such as a heat-shrinkable film or label that can be used for food, beverages, pharmaceuticals / medical products, cosmetics, toiletries, or industrial / agricultural products. Below, we will describe the case of recycling waste heat-shrinkable film, which is a typical printed film.

[0025] Figure 2 is a schematic plan view showing an example of a printed film. In this example, the printed film 40 is a heat-shrinkable film having a printed layer in its pre-heat-shrink state. The printed film 40 is a long film having a width direction and a longitudinal direction. The printed film 40 is managed in a roll form for storage and handling purposes. The printed film 40 may be heat-shrinkable mainly in the transverse axis direction (width direction) for use as a tubular label, for example. The heat shrinkage rate (main shrinkage direction) of the resin layer 42 (see Figure 3) is appropriately selected considering ease of attachment to containers, etc., when used as a label, but for example, it is preferably 30% or more, and more preferably 50% or more, when immersed in 90°C hot water for 10 seconds. As shown in Figure 2, the printed film 40 includes a product portion 400 and edge portions 410A and 410B. The edge portions 410 are provided at positions adjacent to each of the ends of the product portion 400 in the width direction. The product section 400 and the ear section 410 are each printed with a design. Printing onto the film is done, for example, by using a gravure printing plate.

[0026] The product section 400 is used for packaging plastic containers, glass containers, and paper containers. Each of the tab sections 410A and 410B has information printed on it to confirm the printing status of the product section 400. The tab sections 410 are cut and wound up before the product section 400 is shipped. This forms a wound body of the product section 400 and the tab sections 410.

[0027] The printed film (product section 400) with the design printed on it is attached to the outer circumference of the container body as a label. Methods of attaching it to the container include, for example, wrapping the label around the container, and forming a cylindrical label (hereinafter also referred to as "cylindrical label") by bonding both ends of the printed film with the side where the design is formed facing inward, and then heat-shrinking the cylindrical label after placing it over the container to make the label adhere tightly to the outer circumference of the container body. A cylindrical label is manufactured, for example, by the following method: A long roll of printed film is slit to the width of each design, a solvent or the like is applied to one end in the width direction of the printed film, and the two ends are overlapped and bonded together (center-sealed) to obtain a long roll of cylindrical label. A long roll of cylindrical label is obtained by cutting the long roll of cylindrical label, and one cylindrical label is attached to the container.

[0028] Figure 3 is a schematic diagram showing the III-III cross-section of Figure 2. As shown in Figure 3, the printed film 40 includes a resin layer 42 and a printed layer 44. In this example, the resin layer 42 is a heat-shrinkable film. The printed layer 44 is composed of, for example, a coloring component (colorant) such as ink that forms a pattern. In this example, the object to be packaged is placed on the printed layer 44 side. That is, when packaging is performed with the printed film 40, the printed layer 44 is located on the inside. The printed layer 44 may be a single layer or a multi-layer layer. The thickness of the printed layer 44 is appropriately selected depending on the application, etc., but can be, for example, about 0.1 to 20 μm. An inner coat layer may be provided on the printed layer 44, and an overcoat layer may be provided on the resin layer 42 (on the opposite side from the printed layer 44). The inner coat layer is formed, for example, to improve the slipperiness of the inner surface of the tubular label between the object to be packaged and the mounting device. The overcoat layer is formed, for example, to reduce scratches on the outer surface of the label. Each of the inner coat layer and the overcoat layer is formed, for example, in the printing process of the design. Each of the printed layer 44, the inner coat layer and the overcoat layer is included in the "functional layer" of the present invention.

[0029] The resin layer 42 may consist of a single layer or multiple laminated layers. The resin layer 42 may include layers mixed with different types of resins, or it may include multiple layers, each containing a different type of resin. The overall thickness of the resin layer 42 can be appropriately selected depending on the application, but is preferably 10 μm to 60 μm, more preferably 12 μm to 50 μm, and even more preferably 15 μm to 35 μm. When the thickness of the resin layer 42 is within the above range, excellent heat shrinkability, excellent convertibility such as printing and center sealing, or excellent mounting properties can be obtained. In addition, each layer constituting the resin layer 42 may contain components other than resin. Each layer may contain metal components such as aluminum, antiblocking agents, additives, etc. Examples of additives include heat stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, flame retardants, antibacterial agents, and fluorescent whitening agents.

[0030] Examples of resin types contained in each layer include polyolefin resins, polystyrene resins, polyamide resins, and polyester resins. Examples of polyolefin resins include polypropylene, polyethylene, and cyclic polyolefin resins. Examples of polypropylene resins include binary or ternary random copolymers with propylene as the main component and ethylene, butene, and α-olefin as copolymer components. Specifically, α-olefins are preferably composed of ethylene, 1-butene, 1-hexene, 1-octene, etc., and may contain two or more types of α-olefins. Furthermore, polypropylene resins may be mixtures of different propylene-α-olefin random copolymers. Examples of polyethylene resins include branched low-density polyethylene resins, linear low-density polyethylene resins, high-density polyethylene resins, ethylene-vinyl acetate copolymers, ionomer resins, or mixtures thereof. Also, copolymers of ethylene and α-olefins are used. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene. The copolymer may be a random copolymer or a block copolymer. Examples of cyclic olefin resins include (a) copolymers of ethylene or propylene with cyclic olefins (e.g., norbornene and its derivatives, or tetracyclododecene and its derivatives), (b) ring-opened polymers of the cyclic olefin or copolymers with α-olefins, (c) hydrogenated polymers of (b), and (d) graft-modified products of (a) to (c) using unsaturated carboxylic acids and their derivatives. The above-mentioned cyclic olefins are not particularly limited, and specific examples include norbornene, 6-methylnorbornene, 6-ethylnorbornene, 5-propylnorbornene, 6-n-butylnorbornene, 1-methylnorbornene, 7-methylnorbornene, 5,6-dimethylnorbornene, 5-phenylnorbornene, and 5-benzylnorbornene.Examples of polystyrene resins include homopolymers of styrene monomers and copolymers consisting of styrene monomers and other monomers (conjugated dienes, aliphatic unsaturated carboxylic acid esters, etc.). Specifically, these include aromatic vinyl hydrocarbon-conjugated diene copolymers, mixed resins of aromatic vinyl hydrocarbon-conjugated diene copolymers and aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymers, and rubber-modified impact-resistant polystyrene. More specifically, these include styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-isoprene-butadiene copolymers, styrene-acrylic copolymers, acrylonitrile-butadiene-styrene copolymers, acrylonitrile-styrene copolymers, general-purpose polystyrene (GPPS), and highly branched polystyrene. Examples of polyamide resins include aliphatic polyamides, aromatic polyamides, amorphous polyamides, and polyamide elastomers. Examples of the above-mentioned aliphatic polyamides include aliphatic nylon and its copolymers, specifically polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecaneamide (nylon-11), polylauryl lactam (nylon-12), polyethylenediamine adipamide (nylon-2,6), polytetramethylene adipamide (nylon-4,6), polyhexamethylene adipamide (nylon-6,6), polyhexamethylene sevacamide (nylon-6,10), polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide (nylon-8,6), polydecamethylene adipamide (nylon-10,8), etc. Examples of polyester resins include those obtained by condensation polymerization of a dicarboxylic acid component and a diol component. The types of dicarboxylic acid components mentioned above are not particularly limited, and examples include terephthalic acid, o-phthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, decamethylenecarboxylic acid, their anhydrides, and lower alkyl esters.The types of diol components listed above are not particularly limited, and include ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5- Examples include aliphatic diols such as hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, and polytetramethylene ether glycol; 2,2-bis(4-hydroxycyclohexyl)propane; alkylene oxide adducts of 2,2-bis(4-hydroxycyclohexyl)propane; and alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol.

[0031] Referring again to Figure 1, the resource recycling system S1 includes a printing layer removal device 10, a resin raw material manufacturing device 20, and a film manufacturing device 30. The printing layer removal device 10 is configured to remove the printing layer from, for example, used printed film or labels, selvages cut from printed film and recovered in roll form, or waste printed film generated during the manufacturing process, such as test print films. When removing the printing layer from a tubular label, it is desirable to open the tubular label in advance by peeling off the center seal or the like to make it into a film in order to remove the printing layer efficiently. The history of the printed film from which the printing layer is removed by the printing layer removal device 10 is not particularly limited and may include, for example, unused products, intermediate processed products, leftover products, defective products, prototypes, discarded products, etc. The printing layer removal device 10 removes, for example, the printing layer 44, the inner coat layer, and the overcoat layer (hereinafter also referred to as "printing layer 44, etc.") from a printed film 40. The printing layer removal device 10 will be described in detail later.

[0032] The resin raw material manufacturing apparatus 20 is configured to manufacture resin raw materials using the printed film 40 from which the printed layer 44 and the like have been removed by the printed layer removal apparatus 10. The film manufacturing apparatus 30 is configured to manufacture films using the resin raw materials manufactured by the resin raw material manufacturing apparatus 20.

[0033] Figure 4 is a schematic diagram showing a portion of the front view of the print layer removal device 10. Referring to Figure 4, in the print layer removal device 10, for example, the printed film 40 is conveyed from a feed roll (not shown) to a winding roll. The print layer removal device 10 includes an irradiation device 100, a spraying device 110, a polishing device 120, a washing device 130, and a drying device 140. In the print layer removal device 10, the irradiation device 100, spraying device 110, polishing device 120, washing device 130, and drying device 140 are arranged in this order from upstream to downstream along the conveying path of the printed film 40.

[0034] The irradiation device 100 is configured to process the surface of the printed film 40 by irradiating at least one side (one or both sides) of the printed film 40 with high-energy rays (also referred to as "active energy rays"). The high-energy rays are irradiated, for example, to the surface on which the printed layers 44 are laminated. An example of a high-energy ray is ultraviolet light. Examples of ultraviolet light sources include high-pressure mercury lamps, medium-pressure mercury lamps, xenon lamps, deuterium lamps, argon lamps, metal vapor lasers, excimer lasers, argon lasers, and ultraviolet light-emitting LEDs (Light Emitting Diodes). Note that the high-energy ray does not necessarily have to be ultraviolet light; for example, it may be an electron beam or radiation.

[0035] The irradiation device 100 irradiates the printed film 40 with high-energy rays, for example, so that damage extending in the TD (Transversal Direction) is formed at predetermined intervals in the MD (Machine Direction). The irradiation device 100 may irradiate the printed film 40 with high-energy rays so that damage extending in the MD is formed at predetermined intervals in the TD, or it may irradiate the printed film 40 with high-energy rays so that damage extending in a direction inclined with respect to the TD is formed at predetermined intervals in the MD. Preferably, the damage to the printed film 40 reaches, for example, near the interface between the resin layer 42 and the printed layer 44 in the thickness direction of the printed film 40.

[0036] The spraying device 110 is configured to spray an alkaline solution onto at least one surface of the printed film 40 (for example, the surface irradiated with high-energy rays). The printed layer 44 is peeled off from the resin layer 42 by a reaction between the alkaline solution and the ink, etc. Specifically, the alkaline groups of the alkaline solution combine with the functional groups of the resin contained in the ink, which inhibits adhesion between the resin layer 42 and the ink, and as a result the ink detaches from the resin layer 42.

[0037] Before the alkaline solution is sprayed, the printing layer 44 is irradiated with high-energy rays, so that scratches that reach the resin layer 42 are formed in the printing layer 44 when the alkaline solution is sprayed. As a result, the alkaline solution sprayed onto the printing layer 44 can easily reach the interface between the resin layer 42 and the printing layer 44, and the printing layer 44 can be peeled off from the resin layer 42 relatively easily. As the alkaline solution sprayed by the spraying device 110, for example, a solution containing an inorganic base in water can be used. Specifically, examples of inorganic bases include sodium hydroxide and potassium hydroxide. These inorganic bases are preferably contained at a concentration of 0.1 to 10% by mass relative to the total amount of the alkaline solution. The pH of the alkaline solution should be greater than 7, but considering the ease of treating the waste liquid generated by the spraying of the alkaline solution, it is preferably 7 or more and 11 or less, and more preferably 8 or more and 11 or less.

[0038] The polishing device 120 is configured to physically polish at least one side of the printed film 40. Polishing by the polishing device 120 removes the printed layer 44 that could not be removed by the spraying device 110 from the printed film 40. The polishing device 120 includes, for example, a metal file or a polishing roll (physical processing part). The printed film 40 is transported with the physical processing part in contact with the printed layer 44 of the printed film 40, thereby removing the printed layer 44 from the printed film 40. The waste from the removal of the printed layer 44 generated in this process is collected and discarded, for example, by a suction mechanism (not shown).

[0039] The cleaning device 130 is configured, for example, to spray a cleaning solution such as water onto at least one side of the printed film 40. This washes away any remaining debris on the printed film 40. The drying device 140 is configured, for example, to blow hot air onto at least one side of the printed film 40. This dries the surface of the printed film 40.

[0040] When both sides of the printed film 40 are treated in the irradiation device 100, the spraying device 110, and the polishing device 120, for example, if an overcoat layer is formed on the printed film 40, both the printing layer 44 and the overcoat layer can be removed from the printed film 40. The overcoat layer may contain (meth)acrylic acid ester resins that can cause a decrease in haze in recycled film, but since this method makes it possible to remove the overcoat layer together with the printing layer 44, this effect can be reduced.

[0041] Thus, with the printing layer removal device 10, the printing layer 44 of the printed film 40 is irradiated with high-energy rays, making it easier to remove the printing layer 44, and thus the printing layer 44 can be removed from the printed film 40 with higher precision.

[0042] Furthermore, with the printing layer removal device 10, the alkaline solution penetrates more easily into the interface between the printing layer 44 and the resin layer 42 when the printing layer 44 is irradiated with high-energy rays. Therefore, even if the alkaline solution is a weakly alkaline solution, the printing layer 44 can be removed from the printed film 40 with higher precision.

[0043] Referring again to Figure 1, the recycled film produced by the film manufacturing apparatus 30 is printed on again. That is, printed film 40 is produced again. A portion of the produced printed film 40 is put back into the resource recycling system S1. Resource recycling is achieved by repeating this cycle.

[0044] [2. Manufacturing procedure for recycled film] Figure 5 is a flowchart illustrating an example of the manufacturing procedure for recycled film. Each step shown in this flowchart begins with the film waste material being collected. The film waste material may include various types of film with various types of printing. However, the film waste material does not necessarily have to include various types of film with various types of printing; for example, it may contain only one type of film. For example, only one predetermined type of film may be recycled as film waste material from the waste material collected from a factory, etc.

[0045] Referring to Figure 5, the collected film waste is subjected to a process to remove the printed layer (step S100). In step S100, for example, chemical removal using an alkaline solution and physical removal using mechanical actions such as rubbing, scraping, or peeling are performed.

[0046] Figure 6 is a flowchart showing an example of the processing procedure performed in step S100 of Figure 5. Referring to Figure 6, the irradiation device 100 irradiates the collected film waste with high-energy rays (step S200). The spraying device 110 sprays an alkaline solution onto the printed film 40 that has been irradiated with high-energy rays, thereby subjecting the printed film 40 to a chemical removal treatment (step S210). After the chemical removal treatment (chemical deinking treatment), the polishing device 120 performs a physical removal treatment (physical deinking treatment) on the printed film 40 (step S220). Subsequently, the washing device 130 washes the printed film 40 (step S230), and the drying device 140 dries the printed film 40 (step S240). This completes the printing of the printed film 40 from which the printing layer 44 has been removed.

[0047] Referring again to Figure 5, once the removal of the printing layer is completed in step S100, recycled raw materials are produced by granulating the film waste after the removal of the printing layer (step S110). Step S110 is carried out, for example, by a resin raw material manufacturing apparatus 20. The resin raw material manufacturing apparatus 20 can be implemented, for example, by various known apparatuses capable of granulating film waste. In step S110, the film waste after the removal of the printing layer is processed into granules. Examples of granulation methods include melt granulation and compression granulation. In melt granulation, the melt-kneaded film waste is extruded, and the extruded film waste is water-cooled and cut at the die outlet, thereby processing the film waste into granules. In compression granulation, the film waste is compressed and molded, thereby processing the film waste into granules. In step S110, additives (for example, heat stabilizers, antioxidants, UV absorbers, light stabilizers, lubricants, antistatic agents, flame retardants, antibacterial agents, fluorescent whitening agents, virgin raw materials, antiblocking agents) may be added to the film waste. Granulation in step S110 increases the bulk density of the film waste, reducing the space required for storage of the film waste.

[0048] In step S110, once the recycled raw materials are produced, the film manufacturing apparatus 30 performs a film formation process for the recycled film (step S120). In addition, the resin raw materials used in the production of the recycled film may also include biomass-derived raw materials or chemically recycled raw materials.

[0049] [3. An example of recycled film] Figure 7 is a schematic diagram showing a cross-section of an example of a recycled film to be manufactured. As shown in Figure 7, the recycled film 50 includes an intermediate layer 52 and adjacent layers 51 and 53. In the recycled film 50, the intermediate layer 52 is sandwiched between the adjacent layers 51 and 53. In the recycled film 50, the intermediate layer 52 is made of a resin material containing virgin material and recycled material. Each of the adjacent layers 51 and 53 is made of virgin material. Neither of the adjacent layers 51 and 53 contains recycled material. An adhesive layer may be provided between the intermediate layer 52 and the adjacent layers 51 and 53.

[0050] Examples of resin types that make up the virgin raw materials contained in each layer include polyolefin resins, polystyrene resins, polyamide resins, and polyester resins. Examples of polyolefin resins include polypropylene, polyethylene, and cyclic polyolefin resins. Examples of polypropylene resins include binary or ternary random copolymers with propylene as the main component and ethylene, butene, and α-olefin as copolymer components. Specifically, α-olefins are preferably composed of ethylene, 1-butene, 1-hexene, 1-octene, etc., and may contain two or more types of α-olefins. Furthermore, polypropylene resins may be mixtures of different propylene-α-olefin random copolymers. Examples of polyethylene resins include branched low-density polyethylene resins, linear low-density polyethylene resins, high-density polyethylene resins, ethylene-vinyl acetate copolymers, ionomer resins, or mixtures thereof. Also, copolymers of ethylene and α-olefins are used. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene. The copolymer may be a random copolymer or a block copolymer. Examples of cyclic olefin resins include (a) copolymers of ethylene or propylene with cyclic olefins (e.g., norbornene and its derivatives, or tetracyclododecene and its derivatives), (b) ring-opened polymers of the cyclic olefin or copolymers with α-olefins, (c) hydrogenated polymers of (b), and (d) graft-modified products of (a) to (c) using unsaturated carboxylic acids and their derivatives. The above-mentioned cyclic olefins are not particularly limited, and specific examples include norbornene, 6-methylnorbornene, 6-ethylnorbornene, 5-propylnorbornene, 6-n-butylnorbornene, 1-methylnorbornene, 7-methylnorbornene, 5,6-dimethylnorbornene, 5-phenylnorbornene, and 5-benzylnorbornene.Examples of polystyrene resins include homopolymers of styrene monomers and copolymers consisting of styrene monomers and other monomers (conjugated dienes, aliphatic unsaturated carboxylic acid esters, etc.). Specifically, these include aromatic vinyl hydrocarbon-conjugated diene copolymers, mixed resins of aromatic vinyl hydrocarbon-conjugated diene copolymers and aromatic vinyl hydrocarbon-aliphatic unsaturated carboxylic acid ester copolymers, and rubber-modified impact-resistant polystyrene. More specifically, these include styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-isoprene-butadiene copolymers, styrene-acrylic copolymers, acrylonitrile-butadiene-styrene copolymers, acrylonitrile-styrene copolymers, general-purpose polystyrene (GPPS), and highly branched polystyrene. Examples of polyamide resins include aliphatic polyamides, aromatic polyamides, amorphous polyamides, and polyamide elastomers. Examples of the above-mentioned aliphatic polyamides include aliphatic nylon and its copolymers, specifically polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecaneamide (nylon-11), polylauryl lactam (nylon-12), polyethylenediamine adipamide (nylon-2,6), polytetramethylene adipamide (nylon-4,6), polyhexamethylene adipamide (nylon-6,6), polyhexamethylene sevacamide (nylon-6,10), polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide (nylon-8,6), polydecamethylene adipamide (nylon-10,8), etc. Examples of polyester resins include those obtained by condensation polymerization of a dicarboxylic acid component and a diol component. The types of dicarboxylic acid components mentioned above are not particularly limited, and examples include terephthalic acid, o-phthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, decamethylenecarboxylic acid, their anhydrides, and lower alkyl esters.The types of diol components listed above are not particularly limited, and include ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5- Examples include aliphatic diols such as hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, and polytetramethylene ether glycol; 2,2-bis(4-hydroxycyclohexyl)propane; alkylene oxide adducts of 2,2-bis(4-hydroxycyclohexyl)propane; and alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol.

[0051] [4. Features] As described above, with the printed layer removal device 10 according to this embodiment, the printed layer 44 of the printed film 40 is irradiated with high-energy rays, making it easier to remove the printed layer 44, and thus the printed layer 44 can be removed from the printed film 40 with higher precision.

[0052] Furthermore, with the printing layer removal device 10, the alkaline solution penetrates more easily into the interface between the printing layer 44 and the resin layer 42 when the printing layer 44 is irradiated with high-energy rays. Therefore, even if the alkaline solution is a weakly alkaline solution, the printing layer 44 can be removed from the printed film 40 with higher precision.

[0053] Furthermore, with the printing layer removal device 10, the printing layer 44 is irradiated with high-energy rays, making it easier to perform physical treatment on the printing layer 44 and the interface between the printing layer 44 and the resin layer 42, thus enabling the printing layer 44 to be removed from the film with greater precision.

[0054] [5. Other Embodiments] The concept of the above embodiments is not limited to those described above. Examples of other embodiments to which the concept of the above embodiments can be applied will be described below.

[0055] <5-1> In the above embodiment, the irradiation position of the high-energy beams by the irradiation device 100 was not particularly considered in relation to whether or not the printed layer 44 is formed on the printed film 40. However, the irradiation position of the high-energy beams by the irradiation device 100 may be considered in relation to whether or not the printed layer 44 is formed on the printed film 40.

[0056] Figure 8 is a schematic plan view showing another example of a printed film. As shown in Figure 8, the printed film 40X includes a product section 400X and selvage sections 410AX and 410BX. The selvage sections 410X are located adjacent to each end of the product section 400X in the width direction. A design is printed on each of the product section 400X and the selvage sections 410X. The product section 400X includes a first region P1 and a second region P2. The first region P1 is a region where the printed layer is laminated, and the second region P2 is a region where the printed layer is not laminated. For example, the irradiation device 100 may irradiate the first region P1 with high-energy rays, but may not irradiate the second region P2 with high-energy rays. This makes it possible to shorten the time required for film processing compared to the case where high-energy rays are irradiated to both the first region P1 and the second region P2.

[0057] Figure 9 is a flowchart showing an example of the irradiation procedure using the irradiation device 100. Referring to Figure 9, the irradiation device 100 determines whether or not a printed layer is stacked at the location where the high-energy rays are to be irradiated (step S300). This determination is made, for example, by a controller included in the irradiation device 100 referring to the detection result from a sensor included in the irradiation device 100 (for example, a sensor that detects light transmittance). If it is determined that a printed layer is stacked at the location where the high-energy rays are to be irradiated (YES in step S300), the irradiation device 100 irradiates the printed film 40 with high-energy rays (step S310). On the other hand, if it is determined that a printed layer is not stacked at the location where the high-energy rays are to be irradiated (NO in step S300), the irradiation device 100 does not irradiate the printed film 40 with high-energy rays (step S320). This makes it possible to shorten the time required for film processing compared to the case where high-energy rays are irradiated in the first region P1 and the second region P2.

[0058] <5-2> Furthermore, in the above embodiment, the printing layer removal device 10 applied both chemical and physical removal treatments to the printed film 40. However, the printing layer removal device 10 does not necessarily have to apply both chemical and physical removal treatments to the printed film 40. For example, the printing layer removal device 10 may apply at least one of the chemical and physical removal treatments to the printed film 40. Also, the printing layer removal device 10 does not necessarily have to wash and dry the printed film 40.

[0059] <5-3> Furthermore, in the above embodiment, the polishing device 120 may be replaced with, for example, a blasting device, a metal rotating brush, a rotating blade, a scraper, a belt sander, etc., or may be used in combination with these. Also, in the above embodiment, the polishing device 120 and the cleaning device 130 may be replaced with, for example, a wet blasting device, a high-pressure cleaning device, etc.

[0060] <5-4> Furthermore, in the above embodiment, the printed film 40 was conveyed by roll to roll. However, the printed film 40 does not necessarily have to be conveyed by roll to roll. The printed film 40 may be in sheet form, for example, and each sheet of printed film 40 may be conveyed from upstream to downstream by a conveying device such as a belt conveyor. In addition, the printed film 40 may be crushed into fluff form. In this case, the fluff-shaped printed film 40 is irradiated with high-energy rays, and then, for example, an alkaline solution is sprayed onto the crushed printed film 40, or it is immersed in an alkaline solution.

[0061] <5-5> Furthermore, in the above embodiment, an alkaline solution was used to remove the printed layer 44 from the resin layer 42, but a surfactant or an alcohol-based solvent may be used as the desorbing liquid for the printed layer. When a surfactant is used as the desorbing liquid, the lipophilic group of the surfactant is adsorbed onto the oily component of the ink in the printed layer 44, and the hydrophilic group of the surfactant exerts a force that causes it to disperse in water, thereby removing the ink. The surfactant is not particularly limited, and known surfactants can be used, such as anionic surfactants, nonionic surfactants, amphoteric surfactants, cationic surfactants, etc. Furthermore, when an alkaline solution and a surfactant are used together, their interaction enables more precise removal.

[0062] Embodiments of the present invention have been described illustratively above. That is, a detailed description and accompanying drawings have been disclosed for illustrative purposes. Therefore, some of the components described in the detailed description and accompanying drawings may not be essential for solving the problem. Consequently, the mere fact that these non-essential components are described in the detailed description and accompanying drawings does not mean that they should be immediately assumed to be essential.

[0063] Furthermore, the above embodiments are merely illustrative in every respect of the present invention. The above embodiments can be improved or modified in various ways within the scope of the present invention. For example, at least a part of the configuration of one embodiment may be combined with at least a part of the configuration of any other embodiment. In other words, in carrying out the present invention, specific configurations can be appropriately adopted depending on the embodiment. [Explanation of Symbols]

[0064] 10 Printed layer removal device, 20 Resin raw material manufacturing device, 30 Film manufacturing device, 40 Printed film, 42 Resin layer, 44 Printed layer, 50 Recycled film, 51, 53 Adjacent layers, 52 Intermediate layer, 100 Irradiation device, 110 Spraying device, 120 Polishing device, 130 Washing device, 140 Drying device, 400 Product section, 410 Edge section, P1 First area, P2 Second area, S1 Resource recycling system.

Claims

1. A removal method for removing a functional layer from a film containing a functional layer, The steps include processing the film by irradiating the functional layer with high-energy rays, A removal method comprising the step of removing the functional layer from the processed film.

2. The removal method according to claim 1, wherein the step of removing the functional layer includes the step of removing the functional layer by using a desorption liquid.

3. The aforementioned detached liquid is an alkaline solution, The removal method according to claim 2, wherein the pH of the alkaline solution is 8 or higher and 11 or lower.

4. The removal method according to any one of claims 1 to 3, wherein the step of removing the functional layer includes the step of removing the functional layer by subjecting it to a physical process.

5. The removal method according to any one of claims 1 to 3, wherein the step of removing the functional layer includes the step of washing the film.

6. The film includes a first region on which the functional layer is laminated and a second region on which the functional layer is not laminated. The removal method according to any one of claims 1 to 3, wherein in the step of performing the processing, the high-energy ray is irradiated to the first region but not to the second region.

7. A step of producing a film from which the functional layer has been removed by using the removal method described in any one of claims 1 to 3, A method for manufacturing a recycled film, comprising the step of manufacturing a recycled film by using a film from which the functional layer has been removed.

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